accounts/abi: embed Go template instead of string literal (#30098)

refactor(accounts/abi): use embed pkg to split default template to file

.github/CODEOWNERS

@@ -4,13 +4,18 @@
 accounts/usbwallet              @karalabe
 accounts/scwallet               @gballet
 accounts/abi                    @gballet @MariusVanDerWijden
+beacon/engine                   @lightclient
 cmd/clef                        @holiman
+cmd/evm                         @holiman @MariusVanDerWijden @lightclient
 consensus                       @karalabe
 core/                           @karalabe @holiman @rjl493456442
 eth/                            @karalabe @holiman @rjl493456442
-eth/catalyst/                   @gballet
+eth/catalyst/                   @gballet @lightclient
 eth/tracers/                    @s1na
-graphql/                        @gballet @s1na
+core/tracing/                   @s1na
+graphql/                        @s1na
+internal/ethapi                 @lightclient
+internal/era                    @lightclient
 les/                            @zsfelfoldi @rjl493456442
 light/                          @zsfelfoldi @rjl493456442
 node/                           @fjl

.github/CONTRIBUTING.md

@@ -35,6 +35,6 @@ and help.
 
 ## Configuration, dependencies, and tests
 
-Please see the [Developers' Guide](https://geth.ethereum.org/docs/developers/devguide)
+Please see the [Developers' Guide](https://geth.ethereum.org/docs/developers/geth-developer/dev-guide)
 for more details on configuring your environment, managing project dependencies
 and testing procedures.

.github/workflows/go.yml

@@ -0,0 +1,24 @@
+name: i386 linux tests
+
+on:
+  push:
+    branches: [ master ]
+  pull_request:
+    branches: [ master ]
+  workflow_dispatch:
+
+jobs:
+  build:
+    runs-on: self-hosted
+    steps:
+      - uses: actions/checkout@v4
+      - name: Set up Go
+        uses: actions/setup-go@v5
+        with:
+          go-version: 1.21.4
+          cache: false
+      - name: Run tests
+        run: go test -short ./...
+        env:
+          GOOS: linux
+          GOARCH: 386

.gitignore

@@ -47,3 +47,6 @@ profile.cov
 /dashboard/assets/package-lock.json
 
 **/yarn-error.log
+logs/
+
+tests/spec-tests/

.golangci.yml

@@ -6,13 +6,10 @@ run:
   # default is true. Enables skipping of directories:
   #   vendor$, third_party$, testdata$, examples$, Godeps$, builtin$
   skip-dirs-use-default: true
-  skip-files:
-    - core/genesis_alloc.go
 
 linters:
   disable-all: true
   enable:
-    - goconst
     - goimports
     - gosimple
     - govet
@@ -26,7 +23,10 @@ linters:
     - durationcheck
     - exportloopref
     - whitespace
+    - revive # only certain checks enabled
 
+    ### linters we tried and will not be using:
+    ###
     # - structcheck # lots of false positives
     # - errcheck #lot of false positives
     # - contextcheck
@@ -39,16 +39,27 @@ linters:
 linters-settings:
   gofmt:
     simplify: true
-  goconst:
-    min-len: 3 # minimum length of string constant
-    min-occurrences: 6 # minimum number of occurrences
+  revive:
+    enable-all-rules: false
+    # here we enable specific useful rules
+    # see https://golangci-lint.run/usage/linters/#revive for supported rules
+    rules:
+      - name: receiver-naming
+        severity: warning
+        disabled: false
+        exclude: [""]
 
 issues:
+  exclude-files:
+    - core/genesis_alloc.go
   exclude-rules:
     - path: crypto/bn256/cloudflare/optate.go
       linters:
         - deadcode
         - staticcheck
+    - path: crypto/bn256/
+      linters:
+        - revive
     - path: internal/build/pgp.go
       text: 'SA1019: "golang.org/x/crypto/openpgp" is deprecated: this package is unmaintained except for security fixes.'
     - path: core/vm/contracts.go

.mailmap

@@ -56,7 +56,6 @@ Diederik Loerakker <proto@protolambda.com>
 Dimitry Khokhlov <winsvega@mail.ru>
 
 Domino Valdano <dominoplural@gmail.com>
-Domino Valdano <dominoplural@gmail.com> <jeff@okcupid.com>
 
 Edgar Aroutiounian <edgar.factorial@gmail.com>
 

.travis.yml

@@ -9,26 +9,14 @@ jobs:
         - azure-osx
 
   include:
-    # This builder only tests code linters on latest version of Go
-    - stage: lint
-      os: linux
-      dist: bionic
-      go: 1.20.x
-      env:
-        - lint
-      git:
-        submodules: false # avoid cloning ethereum/tests
-      script:
-        - go run build/ci.go lint
-
     # These builders create the Docker sub-images for multi-arch push and each
     # will attempt to push the multi-arch image if they are the last builder
     - stage: build
       if: type = push
       os: linux
       arch: amd64
-      dist: bionic
-      go: 1.20.x
+      dist: noble
+      go: 1.22.x
       env:
         - docker
       services:
@@ -44,8 +32,8 @@ jobs:
       if: type = push
       os: linux
       arch: arm64
-      dist: bionic
-      go: 1.20.x
+      dist: noble
+      go: 1.22.x
       env:
         - docker
       services:
@@ -57,50 +45,24 @@ jobs:
       script:
         - go run build/ci.go docker -image -manifest amd64,arm64 -upload ethereum/client-go
 
-    # This builder does the Ubuntu PPA upload
-    - stage: build
-      if: type = push
-      os: linux
-      dist: bionic
-      go: 1.20.x
-      env:
-        - ubuntu-ppa
-        - GO111MODULE=on
-      git:
-        submodules: false # avoid cloning ethereum/tests
-      addons:
-        apt:
-          packages:
-            - devscripts
-            - debhelper
-            - dput
-            - fakeroot
-            - python-bzrlib
-            - python-paramiko
-      script:
-        - echo '|1|7SiYPr9xl3uctzovOTj4gMwAC1M=|t6ReES75Bo/PxlOPJ6/GsGbTrM0= ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0aKz5UTUndYgIGG7dQBV+HaeuEZJ2xPHo2DS2iSKvUL4xNMSAY4UguNW+pX56nAQmZKIZZ8MaEvSj6zMEDiq6HFfn5JcTlM80UwlnyKe8B8p7Nk06PPQLrnmQt5fh0HmEcZx+JU9TZsfCHPnX7MNz4ELfZE6cFsclClrKim3BHUIGq//t93DllB+h4O9LHjEUsQ1Sr63irDLSutkLJD6RXchjROXkNirlcNVHH/jwLWR5RcYilNX7S5bIkK8NlWPjsn/8Ua5O7I9/YoE97PpO6i73DTGLh5H9JN/SITwCKBkgSDWUt61uPK3Y11Gty7o2lWsBjhBUm2Y38CBsoGmBw==' >> ~/.ssh/known_hosts
-        - go run build/ci.go debsrc -upload ethereum/ethereum -sftp-user geth-ci -signer "Go Ethereum Linux Builder <geth-ci@ethereum.org>"
-
     # This builder does the Linux Azure uploads
     - stage: build
       if: type = push
       os: linux
-      dist: bionic
+      dist: noble
       sudo: required
-      go: 1.20.x
+      go: 1.22.x
       env:
         - azure-linux
-        - GO111MODULE=on
       git:
         submodules: false # avoid cloning ethereum/tests
-      addons:
-        apt:
-          packages:
-            - gcc-multilib
       script:
-        # Build for the primary platforms that Trusty can manage
+        # build amd64
         - go run build/ci.go install -dlgo
         - go run build/ci.go archive -type tar -signer LINUX_SIGNING_KEY -signify SIGNIFY_KEY -upload gethstore/builds
+
+        # build 386
+        - sudo -E apt-get -yq --no-install-suggests --no-install-recommends install gcc-multilib
         - go run build/ci.go install -dlgo -arch 386
         - go run build/ci.go archive -arch 386 -type tar -signer LINUX_SIGNING_KEY -signify SIGNIFY_KEY -upload gethstore/builds
 
@@ -121,56 +83,60 @@ jobs:
     - stage: build
       if: type = push
       os: osx
-      go: 1.20.x
+      osx_image: xcode14.2
+      go: 1.22.x
       env:
         - azure-osx
-        - GO111MODULE=on
       git:
         submodules: false # avoid cloning ethereum/tests
       script:
         - go run build/ci.go install -dlgo
         - go run build/ci.go archive -type tar -signer OSX_SIGNING_KEY -signify SIGNIFY_KEY -upload gethstore/builds
+        - go run build/ci.go install -dlgo -arch arm64
+        - go run build/ci.go archive -arch arm64 -type tar -signer OSX_SIGNING_KEY -signify SIGNIFY_KEY -upload gethstore/builds
 
     # These builders run the tests
     - stage: build
+      if: type = push
       os: linux
       arch: amd64
-      dist: bionic
-      go: 1.20.x
-      env:
-        - GO111MODULE=on
+      dist: noble
+      go: 1.22.x
       script:
-        - go run build/ci.go test $TEST_PACKAGES
+        - travis_wait 45 go run build/ci.go test $TEST_PACKAGES
 
     - stage: build
-      if: type = pull_request
+      if: type = push
       os: linux
-      arch: arm64
-      dist: bionic
-      go: 1.19.x
-      env:
-        - GO111MODULE=on
+      dist: noble
+      go: 1.21.x
       script:
-        - go run build/ci.go test $TEST_PACKAGES
+        - travis_wait 45 go run build/ci.go test $TEST_PACKAGES
 
+    # This builder does the Ubuntu PPA nightly uploads
     - stage: build
+      if: type = cron || (type = push && tag ~= /^v[0-9]/)
       os: linux
-      dist: bionic
-      go: 1.19.x
+      dist: noble
+      go: 1.22.x
       env:
-        - GO111MODULE=on
+        - ubuntu-ppa
+      git:
+        submodules: false # avoid cloning ethereum/tests
+      before_install:
+        - sudo -E apt-get -yq --no-install-suggests --no-install-recommends install devscripts debhelper dput fakeroot
       script:
-        - go run build/ci.go test $TEST_PACKAGES
+        - echo '|1|7SiYPr9xl3uctzovOTj4gMwAC1M=|t6ReES75Bo/PxlOPJ6/GsGbTrM0= ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0aKz5UTUndYgIGG7dQBV+HaeuEZJ2xPHo2DS2iSKvUL4xNMSAY4UguNW+pX56nAQmZKIZZ8MaEvSj6zMEDiq6HFfn5JcTlM80UwlnyKe8B8p7Nk06PPQLrnmQt5fh0HmEcZx+JU9TZsfCHPnX7MNz4ELfZE6cFsclClrKim3BHUIGq//t93DllB+h4O9LHjEUsQ1Sr63irDLSutkLJD6RXchjROXkNirlcNVHH/jwLWR5RcYilNX7S5bIkK8NlWPjsn/8Ua5O7I9/YoE97PpO6i73DTGLh5H9JN/SITwCKBkgSDWUt61uPK3Y11Gty7o2lWsBjhBUm2Y38CBsoGmBw==' >> ~/.ssh/known_hosts
+        - go run build/ci.go debsrc -upload ethereum/ethereum -sftp-user geth-ci -signer "Go Ethereum Linux Builder <geth-ci@ethereum.org>"
 
     # This builder does the Azure archive purges to avoid accumulating junk
     - stage: build
       if: type = cron
       os: linux
-      dist: bionic
-      go: 1.20.x
+      dist: noble
+      go: 1.22.x
       env:
         - azure-purge
-        - GO111MODULE=on
       git:
         submodules: false # avoid cloning ethereum/tests
       script:
@@ -180,10 +146,9 @@ jobs:
     - stage: build
       if: type = cron
       os: linux
-      dist: bionic
-      go: 1.20.x
+      dist: noble
+      go: 1.22.x
       env:
-        - GO111MODULE=on
+        - racetests
       script:
-        - go run build/ci.go test  -race $TEST_PACKAGES
-
+        - travis_wait 60 go run build/ci.go test -race $TEST_PACKAGES

Dockerfile

@@ -4,7 +4,7 @@ ARG VERSION=""
 ARG BUILDNUM=""
 
 # Build Geth in a stock Go builder container
-FROM golang:1.20-alpine as builder
+FROM golang:1.22-alpine as builder
 
 RUN apk add --no-cache gcc musl-dev linux-headers git
 
@@ -25,7 +25,7 @@ COPY --from=builder /go-ethereum/build/bin/geth /usr/local/bin/
 EXPOSE 8545 8546 30303 30303/udp
 ENTRYPOINT ["geth"]
 
-# Add some metadata labels to help programatic image consumption
+# Add some metadata labels to help programmatic image consumption
 ARG COMMIT=""
 ARG VERSION=""
 ARG BUILDNUM=""

Dockerfile.alltools

@@ -4,7 +4,7 @@ ARG VERSION=""
 ARG BUILDNUM=""
 
 # Build Geth in a stock Go builder container
-FROM golang:1.20-alpine as builder
+FROM golang:1.22-alpine as builder
 
 RUN apk add --no-cache gcc musl-dev linux-headers git
 
@@ -24,7 +24,7 @@ COPY --from=builder /go-ethereum/build/bin/* /usr/local/bin/
 
 EXPOSE 8545 8546 30303 30303/udp
 
-# Add some metadata labels to help programatic image consumption
+# Add some metadata labels to help programmatic image consumption
 ARG COMMIT=""
 ARG VERSION=""
 ARG BUILDNUM=""

Makefile

@@ -2,33 +2,43 @@
 # with Go source code. If you know what GOPATH is then you probably
 # don't need to bother with make.
 
-.PHONY: geth android ios evm all test clean
+.PHONY: geth all test lint fmt clean devtools help
 
 GOBIN = ./build/bin
 GO ?= latest
-GORUN = env GO111MODULE=on go run
+GORUN = go run
 
+#? geth: Build geth.
 geth:
 	$(GORUN) build/ci.go install ./cmd/geth
 	@echo "Done building."
 	@echo "Run \"$(GOBIN)/geth\" to launch geth."
 
+#? all: Build all packages and executables.
 all:
 	$(GORUN) build/ci.go install
 
+#? test: Run the tests.
 test: all
 	$(GORUN) build/ci.go test
 
+#? lint: Run certain pre-selected linters.
 lint: ## Run linters.
 	$(GORUN) build/ci.go lint
 
+#? fmt: Ensure consistent code formatting.
+fmt:
+	gofmt -s -w $(shell find . -name "*.go")
+
+#? clean: Clean go cache, built executables, and the auto generated folder.
 clean:
-	env GO111MODULE=on go clean -cache
+	go clean -cache
 	rm -fr build/_workspace/pkg/ $(GOBIN)/*
 
 # The devtools target installs tools required for 'go generate'.
 # You need to put $GOBIN (or $GOPATH/bin) in your PATH to use 'go generate'.
 
+#? devtools: Install recommended developer tools.
 devtools:
 	env GOBIN= go install golang.org/x/tools/cmd/stringer@latest
 	env GOBIN= go install github.com/fjl/gencodec@latest
@@ -36,3 +46,12 @@ devtools:
 	env GOBIN= go install ./cmd/abigen
 	@type "solc" 2> /dev/null || echo 'Please install solc'
 	@type "protoc" 2> /dev/null || echo 'Please install protoc'
+
+#? help: Get more info on make commands.
+help: Makefile
+	@echo ''
+	@echo 'Usage:'
+	@echo '  make [target]'
+	@echo ''
+	@echo 'Targets:'
+	@sed -n 's/^#?//p' $< | column -t -s ':' |  sort | sed -e 's/^/ /'

README.md

@@ -1,12 +1,12 @@
 ## Go Ethereum
 
-Official Golang execution layer implementation of the Ethereum protocol.
+Golang execution layer implementation of the Ethereum protocol.
 
 [![API Reference](
-https://camo.githubusercontent.com/915b7be44ada53c290eb157634330494ebe3e30a/68747470733a2f2f676f646f632e6f72672f6769746875622e636f6d2f676f6c616e672f6764646f3f7374617475732e737667
+https://pkg.go.dev/badge/github.com/ethereum/go-ethereum
 )](https://pkg.go.dev/github.com/ethereum/go-ethereum?tab=doc)
 [![Go Report Card](https://goreportcard.com/badge/github.com/ethereum/go-ethereum)](https://goreportcard.com/report/github.com/ethereum/go-ethereum)
-[![Travis](https://travis-ci.com/ethereum/go-ethereum.svg?branch=master)](https://travis-ci.com/ethereum/go-ethereum)
+[![Travis](https://app.travis-ci.com/ethereum/go-ethereum.svg?branch=master)](https://app.travis-ci.com/github/ethereum/go-ethereum)
 [![Discord](https://img.shields.io/badge/discord-join%20chat-blue.svg)](https://discord.gg/nthXNEv)
 
 Automated builds are available for stable releases and the unstable master branch. Binary
@@ -16,7 +16,7 @@ archives are published at https://geth.ethereum.org/downloads/.
 
 For prerequisites and detailed build instructions please read the [Installation Instructions](https://geth.ethereum.org/docs/getting-started/installing-geth).
 
-Building `geth` requires both a Go (version 1.19 or later) and a C compiler. You can install
+Building `geth` requires both a Go (version 1.21 or later) and a C compiler. You can install
 them using your favourite package manager. Once the dependencies are installed, run
 
 ```shell
@@ -36,10 +36,10 @@ directory.
 
 |  Command   | Description                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
 | :--------: | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-| **`geth`** | Our main Ethereum CLI client. It is the entry point into the Ethereum network (main-, test- or private net), capable of running as a full node (default), archive node (retaining all historical state) or a light node (retrieving data live). It can be used by other processes as a gateway into the Ethereum network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. `geth --help` and the [CLI page](https://geth.ethereum.org/docs/interface/command-line-options) for command line options. |
+| **`geth`** | Our main Ethereum CLI client. It is the entry point into the Ethereum network (main-, test- or private net), capable of running as a full node (default), archive node (retaining all historical state) or a light node (retrieving data live). It can be used by other processes as a gateway into the Ethereum network via JSON RPC endpoints exposed on top of HTTP, WebSocket and/or IPC transports. `geth --help` and the [CLI page](https://geth.ethereum.org/docs/fundamentals/command-line-options) for command line options. |
 |   `clef`   | Stand-alone signing tool, which can be used as a backend signer for `geth`.                                                                                                                                                                                                                                                                                                                                                                                                                                                        |
 |  `devp2p`  | Utilities to interact with nodes on the networking layer, without running a full blockchain.                                                                                                                                                                                                                                                                                                                                                                                                                                       |
-|  `abigen`  | Source code generator to convert Ethereum contract definitions into easy-to-use, compile-time type-safe Go packages. It operates on plain [Ethereum contract ABIs](https://docs.soliditylang.org/en/develop/abi-spec.html) with expanded functionality if the contract bytecode is also available. However, it also accepts Solidity source files, making development much more streamlined. Please see our [Native DApps](https://geth.ethereum.org/docs/dapp/native-bindings) page for details.                                  |
+|  `abigen`  | Source code generator to convert Ethereum contract definitions into easy-to-use, compile-time type-safe Go packages. It operates on plain [Ethereum contract ABIs](https://docs.soliditylang.org/en/develop/abi-spec.html) with expanded functionality if the contract bytecode is also available. However, it also accepts Solidity source files, making development much more streamlined. Please see our [Native DApps](https://geth.ethereum.org/docs/developers/dapp-developer/native-bindings) page for details.                                  |
 | `bootnode` | Stripped down version of our Ethereum client implementation that only takes part in the network node discovery protocol, but does not run any of the higher level application protocols. It can be used as a lightweight bootstrap node to aid in finding peers in private networks.                                                                                                                                                                                                                                               |
 |   `evm`    | Developer utility version of the EVM (Ethereum Virtual Machine) that is capable of running bytecode snippets within a configurable environment and execution mode. Its purpose is to allow isolated, fine-grained debugging of EVM opcodes (e.g. `evm --code 60ff60ff --debug run`).                                                                                                                                                                                                                                               |
 | `rlpdump`  | Developer utility tool to convert binary RLP ([Recursive Length Prefix](https://ethereum.org/en/developers/docs/data-structures-and-encoding/rlp)) dumps (data encoding used by the Ethereum protocol both network as well as consensus wise) to user-friendlier hierarchical representation (e.g. `rlpdump --hex CE0183FFFFFFC4C304050583616263`).                                                                                                                                                                                |
@@ -47,7 +47,7 @@ directory.
 ## Running `geth`
 
 Going through all the possible command line flags is out of scope here (please consult our
-[CLI Wiki page](https://geth.ethereum.org/docs/interface/command-line-options)),
+[CLI Wiki page](https://geth.ethereum.org/docs/fundamentals/command-line-options)),
 but we've enumerated a few common parameter combos to get you up to speed quickly
 on how you can run your own `geth` instance.
 
@@ -82,10 +82,10 @@ This command will:
  * Start `geth` in snap sync mode (default, can be changed with the `--syncmode` flag),
    causing it to download more data in exchange for avoiding processing the entire history
    of the Ethereum network, which is very CPU intensive.
- * Start the built-in interactive [JavaScript console](https://geth.ethereum.org/docs/interface/javascript-console),
+ * Start the built-in interactive [JavaScript console](https://geth.ethereum.org/docs/interacting-with-geth/javascript-console),
    (via the trailing `console` subcommand) through which you can interact using [`web3` methods](https://github.com/ChainSafe/web3.js/blob/0.20.7/DOCUMENTATION.md) 
    (note: the `web3` version bundled within `geth` is very old, and not up to date with official docs),
-   as well as `geth`'s own [management APIs](https://geth.ethereum.org/docs/rpc/server).
+   as well as `geth`'s own [management APIs](https://geth.ethereum.org/docs/interacting-with-geth/rpc).
    This tool is optional and if you leave it out you can always attach it to an already running
    `geth` instance with `geth attach`.
 
@@ -123,15 +123,6 @@ use separate accounts for play and real money. Unless you manually move
 accounts, `geth` will by default correctly separate the two networks and will not make any
 accounts available between them.*
 
-### Full node on the Rinkeby test network
-
-Go Ethereum also supports connecting to the older proof-of-authority based test network
-called [*Rinkeby*](https://www.rinkeby.io) which is operated by members of the community.
-
-```shell
-$ geth --rinkeby console
-```
-
 ### Configuration
 
 As an alternative to passing the numerous flags to the `geth` binary, you can also pass a
@@ -175,7 +166,7 @@ accessible from the outside.
 As a developer, sooner rather than later you'll want to start interacting with `geth` and the
 Ethereum network via your own programs and not manually through the console. To aid
 this, `geth` has built-in support for a JSON-RPC based APIs ([standard APIs](https://ethereum.github.io/execution-apis/api-documentation/)
-and [`geth` specific APIs](https://geth.ethereum.org/docs/rpc/server)).
+and [`geth` specific APIs](https://geth.ethereum.org/docs/interacting-with-geth/rpc)).
 These can be exposed via HTTP, WebSockets and IPC (UNIX sockets on UNIX based
 platforms, and named pipes on Windows).
 

accounts/abi/abi.go

@@ -22,13 +22,14 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"math/big"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
 // The ABI holds information about a contract's context and available
-// invokable methods. It will allow you to type check function calls and
+// invocable methods. It will allow you to type check function calls and
 // packs data accordingly.
 type ABI struct {
 	Constructor Method
@@ -222,6 +223,17 @@ func (abi *ABI) EventByID(topic common.Hash) (*Event, error) {
 	return nil, fmt.Errorf("no event with id: %#x", topic.Hex())
 }
 
+// ErrorByID looks up an error by the 4-byte id,
+// returns nil if none found.
+func (abi *ABI) ErrorByID(sigdata [4]byte) (*Error, error) {
+	for _, errABI := range abi.Errors {
+		if bytes.Equal(errABI.ID[:4], sigdata[:]) {
+			return &errABI, nil
+		}
+	}
+	return nil, fmt.Errorf("no error with id: %#x", sigdata[:])
+}
+
 // HasFallback returns an indicator whether a fallback function is included.
 func (abi *ABI) HasFallback() bool {
 	return abi.Fallback.Type == Fallback
@@ -235,21 +247,65 @@ func (abi *ABI) HasReceive() bool {
 // revertSelector is a special function selector for revert reason unpacking.
 var revertSelector = crypto.Keccak256([]byte("Error(string)"))[:4]
 
+// panicSelector is a special function selector for panic reason unpacking.
+var panicSelector = crypto.Keccak256([]byte("Panic(uint256)"))[:4]
+
+// panicReasons map is for readable panic codes
+// see this linkage for the details
+// https://docs.soliditylang.org/en/v0.8.21/control-structures.html#panic-via-assert-and-error-via-require
+// the reason string list is copied from ether.js
+// https://github.com/ethers-io/ethers.js/blob/fa3a883ff7c88611ce766f58bdd4b8ac90814470/src.ts/abi/interface.ts#L207-L218
+var panicReasons = map[uint64]string{
+	0x00: "generic panic",
+	0x01: "assert(false)",
+	0x11: "arithmetic underflow or overflow",
+	0x12: "division or modulo by zero",
+	0x21: "enum overflow",
+	0x22: "invalid encoded storage byte array accessed",
+	0x31: "out-of-bounds array access; popping on an empty array",
+	0x32: "out-of-bounds access of an array or bytesN",
+	0x41: "out of memory",
+	0x51: "uninitialized function",
+}
+
 // UnpackRevert resolves the abi-encoded revert reason. According to the solidity
 // spec https://solidity.readthedocs.io/en/latest/control-structures.html#revert,
-// the provided revert reason is abi-encoded as if it were a call to a function
-// `Error(string)`. So it's a special tool for it.
+// the provided revert reason is abi-encoded as if it were a call to function
+// `Error(string)` or `Panic(uint256)`. So it's a special tool for it.
 func UnpackRevert(data []byte) (string, error) {
 	if len(data) < 4 {
 		return "", errors.New("invalid data for unpacking")
 	}
-	if !bytes.Equal(data[:4], revertSelector) {
+	switch {
+	case bytes.Equal(data[:4], revertSelector):
+		typ, err := NewType("string", "", nil)
+		if err != nil {
+			return "", err
+		}
+		unpacked, err := (Arguments{{Type: typ}}).Unpack(data[4:])
+		if err != nil {
+			return "", err
+		}
+		return unpacked[0].(string), nil
+	case bytes.Equal(data[:4], panicSelector):
+		typ, err := NewType("uint256", "", nil)
+		if err != nil {
+			return "", err
+		}
+		unpacked, err := (Arguments{{Type: typ}}).Unpack(data[4:])
+		if err != nil {
+			return "", err
+		}
+		pCode := unpacked[0].(*big.Int)
+		// uint64 safety check for future
+		// but the code is not bigger than MAX(uint64) now
+		if pCode.IsUint64() {
+			if reason, ok := panicReasons[pCode.Uint64()]; ok {
+				return reason, nil
+			}
+		}
+		return fmt.Sprintf("unknown panic code: %#x", pCode), nil
+	default:
 		return "", errors.New("invalid data for unpacking")
 	}
-	typ, _ := NewType("string", "", nil)
-	unpacked, err := (Arguments{{Type: typ}}).Unpack(data[4:])
-	if err != nil {
-		return "", err
-	}
-	return unpacked[0].(string), nil
 }

accounts/abi/abi_test.go

@@ -120,6 +120,7 @@ var methods = map[string]Method{
 }
 
 func TestReader(t *testing.T) {
+	t.Parallel()
 	abi := ABI{
 		Methods: methods,
 	}
@@ -151,6 +152,7 @@ func TestReader(t *testing.T) {
 }
 
 func TestInvalidABI(t *testing.T) {
+	t.Parallel()
 	json := `[{ "type" : "function", "name" : "", "constant" : fals }]`
 	_, err := JSON(strings.NewReader(json))
 	if err == nil {
@@ -170,6 +172,7 @@ func TestInvalidABI(t *testing.T) {
 //		constructor(uint256 a, uint256 b) public{}
 //	}
 func TestConstructor(t *testing.T) {
+	t.Parallel()
 	json := `[{	"inputs": [{"internalType": "uint256","name": "a","type": "uint256"	},{	"internalType": "uint256","name": "b","type": "uint256"}],"stateMutability": "nonpayable","type": "constructor"}]`
 	method := NewMethod("", "", Constructor, "nonpayable", false, false, []Argument{{"a", Uint256, false}, {"b", Uint256, false}}, nil)
 	// Test from JSON
@@ -199,6 +202,7 @@ func TestConstructor(t *testing.T) {
 }
 
 func TestTestNumbers(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(jsondata))
 	if err != nil {
 		t.Fatal(err)
@@ -236,6 +240,7 @@ func TestTestNumbers(t *testing.T) {
 }
 
 func TestMethodSignature(t *testing.T) {
+	t.Parallel()
 	m := NewMethod("foo", "foo", Function, "", false, false, []Argument{{"bar", String, false}, {"baz", String, false}}, nil)
 	exp := "foo(string,string)"
 	if m.Sig != exp {
@@ -274,6 +279,7 @@ func TestMethodSignature(t *testing.T) {
 }
 
 func TestOverloadedMethodSignature(t *testing.T) {
+	t.Parallel()
 	json := `[{"constant":true,"inputs":[{"name":"i","type":"uint256"},{"name":"j","type":"uint256"}],"name":"foo","outputs":[],"payable":false,"stateMutability":"pure","type":"function"},{"constant":true,"inputs":[{"name":"i","type":"uint256"}],"name":"foo","outputs":[],"payable":false,"stateMutability":"pure","type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"i","type":"uint256"}],"name":"bar","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"i","type":"uint256"},{"indexed":false,"name":"j","type":"uint256"}],"name":"bar","type":"event"}]`
 	abi, err := JSON(strings.NewReader(json))
 	if err != nil {
@@ -297,6 +303,7 @@ func TestOverloadedMethodSignature(t *testing.T) {
 }
 
 func TestCustomErrors(t *testing.T) {
+	t.Parallel()
 	json := `[{ "inputs": [	{ "internalType": "uint256", "name": "", "type": "uint256" } ],"name": "MyError", "type": "error"} ]`
 	abi, err := JSON(strings.NewReader(json))
 	if err != nil {
@@ -311,6 +318,7 @@ func TestCustomErrors(t *testing.T) {
 }
 
 func TestMultiPack(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(jsondata))
 	if err != nil {
 		t.Fatal(err)
@@ -348,6 +356,7 @@ func ExampleJSON() {
 }
 
 func TestInputVariableInputLength(t *testing.T) {
+	t.Parallel()
 	const definition = `[
 	{ "type" : "function", "name" : "strOne", "constant" : true, "inputs" : [ { "name" : "str", "type" : "string" } ] },
 	{ "type" : "function", "name" : "bytesOne", "constant" : true, "inputs" : [ { "name" : "str", "type" : "bytes" } ] },
@@ -476,6 +485,7 @@ func TestInputVariableInputLength(t *testing.T) {
 }
 
 func TestInputFixedArrayAndVariableInputLength(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(jsondata))
 	if err != nil {
 		t.Error(err)
@@ -650,6 +660,7 @@ func TestInputFixedArrayAndVariableInputLength(t *testing.T) {
 }
 
 func TestDefaultFunctionParsing(t *testing.T) {
+	t.Parallel()
 	const definition = `[{ "name" : "balance", "type" : "function" }]`
 
 	abi, err := JSON(strings.NewReader(definition))
@@ -663,6 +674,7 @@ func TestDefaultFunctionParsing(t *testing.T) {
 }
 
 func TestBareEvents(t *testing.T) {
+	t.Parallel()
 	const definition = `[
 	{ "type" : "event", "name" : "balance" },
 	{ "type" : "event", "name" : "anon", "anonymous" : true},
@@ -739,6 +751,7 @@ func TestBareEvents(t *testing.T) {
 //
 //	receipt{status=1 cgas=23949 bloom=00000000004000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000800000000000000000000000000000000000040200000000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000080000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 logs=[log: b6818c8064f645cd82d99b59a1a267d6d61117ef [75fd880d39c1daf53b6547ab6cb59451fc6452d27caa90e5b6649dd8293b9eed] 000000000000000000000000376c47978271565f56deb45495afa69e59c16ab200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000158 9ae378b6d4409eada347a5dc0c180f186cb62dc68fcc0f043425eb917335aa28 0 95d429d309bb9d753954195fe2d69bd140b4ae731b9b5b605c34323de162cf00 0]}
 func TestUnpackEvent(t *testing.T) {
+	t.Parallel()
 	const abiJSON = `[{"constant":false,"inputs":[{"name":"memo","type":"bytes"}],"name":"receive","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"sender","type":"address"},{"indexed":false,"name":"amount","type":"uint256"},{"indexed":false,"name":"memo","type":"bytes"}],"name":"received","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"sender","type":"address"}],"name":"receivedAddr","type":"event"}]`
 	abi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -777,6 +790,7 @@ func TestUnpackEvent(t *testing.T) {
 }
 
 func TestUnpackEventIntoMap(t *testing.T) {
+	t.Parallel()
 	const abiJSON = `[{"constant":false,"inputs":[{"name":"memo","type":"bytes"}],"name":"receive","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"anonymous":false,"inputs":[{"indexed":false,"name":"sender","type":"address"},{"indexed":false,"name":"amount","type":"uint256"},{"indexed":false,"name":"memo","type":"bytes"}],"name":"received","type":"event"},{"anonymous":false,"inputs":[{"indexed":false,"name":"sender","type":"address"}],"name":"receivedAddr","type":"event"}]`
 	abi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -827,6 +841,7 @@ func TestUnpackEventIntoMap(t *testing.T) {
 }
 
 func TestUnpackMethodIntoMap(t *testing.T) {
+	t.Parallel()
 	const abiJSON = `[{"constant":false,"inputs":[{"name":"memo","type":"bytes"}],"name":"receive","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[],"name":"send","outputs":[{"name":"amount","type":"uint256"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"name":"addr","type":"address"}],"name":"get","outputs":[{"name":"hash","type":"bytes"}],"payable":true,"stateMutability":"payable","type":"function"}]`
 	abi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -877,6 +892,7 @@ func TestUnpackMethodIntoMap(t *testing.T) {
 }
 
 func TestUnpackIntoMapNamingConflict(t *testing.T) {
+	t.Parallel()
 	// Two methods have the same name
 	var abiJSON = `[{"constant":false,"inputs":[{"name":"memo","type":"bytes"}],"name":"get","outputs":[],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[],"name":"send","outputs":[{"name":"amount","type":"uint256"}],"payable":true,"stateMutability":"payable","type":"function"},{"constant":false,"inputs":[{"name":"addr","type":"address"}],"name":"get","outputs":[{"name":"hash","type":"bytes"}],"payable":true,"stateMutability":"payable","type":"function"}]`
 	abi, err := JSON(strings.NewReader(abiJSON))
@@ -960,6 +976,7 @@ func TestUnpackIntoMapNamingConflict(t *testing.T) {
 }
 
 func TestABI_MethodById(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(jsondata))
 	if err != nil {
 		t.Fatal(err)
@@ -992,6 +1009,7 @@ func TestABI_MethodById(t *testing.T) {
 }
 
 func TestABI_EventById(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		name  string
 		json  string
@@ -1057,9 +1075,39 @@ func TestABI_EventById(t *testing.T) {
 	}
 }
 
+func TestABI_ErrorByID(t *testing.T) {
+	t.Parallel()
+	abi, err := JSON(strings.NewReader(`[
+		{"inputs":[{"internalType":"uint256","name":"x","type":"uint256"}],"name":"MyError1","type":"error"},
+		{"inputs":[{"components":[{"internalType":"uint256","name":"a","type":"uint256"},{"internalType":"string","name":"b","type":"string"},{"internalType":"address","name":"c","type":"address"}],"internalType":"struct MyError.MyStruct","name":"x","type":"tuple"},{"internalType":"address","name":"y","type":"address"},{"components":[{"internalType":"uint256","name":"a","type":"uint256"},{"internalType":"string","name":"b","type":"string"},{"internalType":"address","name":"c","type":"address"}],"internalType":"struct MyError.MyStruct","name":"z","type":"tuple"}],"name":"MyError2","type":"error"},
+		{"inputs":[{"internalType":"uint256[]","name":"x","type":"uint256[]"}],"name":"MyError3","type":"error"}
+	]`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for name, m := range abi.Errors {
+		a := fmt.Sprintf("%v", &m)
+		var id [4]byte
+		copy(id[:], m.ID[:4])
+		m2, err := abi.ErrorByID(id)
+		if err != nil {
+			t.Fatalf("Failed to look up ABI error: %v", err)
+		}
+		b := fmt.Sprintf("%v", m2)
+		if a != b {
+			t.Errorf("Error %v (id %x) not 'findable' by id in ABI", name, id)
+		}
+	}
+	// test unsuccessful lookups
+	if _, err = abi.ErrorByID([4]byte{}); err == nil {
+		t.Error("Expected error: no error with this id")
+	}
+}
+
 // TestDoubleDuplicateMethodNames checks that if transfer0 already exists, there won't be a name
 // conflict and that the second transfer method will be renamed transfer1.
 func TestDoubleDuplicateMethodNames(t *testing.T) {
+	t.Parallel()
 	abiJSON := `[{"constant":false,"inputs":[{"name":"to","type":"address"},{"name":"value","type":"uint256"}],"name":"transfer","outputs":[{"name":"ok","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"to","type":"address"},{"name":"value","type":"uint256"},{"name":"data","type":"bytes"}],"name":"transfer0","outputs":[{"name":"ok","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"},{"constant":false,"inputs":[{"name":"to","type":"address"},{"name":"value","type":"uint256"},{"name":"data","type":"bytes"},{"name":"customFallback","type":"string"}],"name":"transfer","outputs":[{"name":"ok","type":"bool"}],"payable":false,"stateMutability":"nonpayable","type":"function"}]`
 	contractAbi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -1089,6 +1137,7 @@ func TestDoubleDuplicateMethodNames(t *testing.T) {
 //		event send();
 //	}
 func TestDoubleDuplicateEventNames(t *testing.T) {
+	t.Parallel()
 	abiJSON := `[{"anonymous": false,"inputs": [{"indexed": false,"internalType": "uint256","name": "a","type": "uint256"}],"name": "send","type": "event"},{"anonymous": false,"inputs": [],"name": "send0","type": "event"},{	"anonymous": false,	"inputs": [],"name": "send","type": "event"}]`
 	contractAbi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -1116,6 +1165,7 @@ func TestDoubleDuplicateEventNames(t *testing.T) {
 //		event send(uint256, uint256);
 //	}
 func TestUnnamedEventParam(t *testing.T) {
+	t.Parallel()
 	abiJSON := `[{ "anonymous": false, "inputs": [{	"indexed": false,"internalType": "uint256",	"name": "","type": "uint256"},{"indexed": false,"internalType": "uint256","name": "","type": "uint256"}],"name": "send","type": "event"}]`
 	contractAbi, err := JSON(strings.NewReader(abiJSON))
 	if err != nil {
@@ -1145,9 +1195,13 @@ func TestUnpackRevert(t *testing.T) {
 		{"", "", errors.New("invalid data for unpacking")},
 		{"08c379a1", "", errors.New("invalid data for unpacking")},
 		{"08c379a00000000000000000000000000000000000000000000000000000000000000020000000000000000000000000000000000000000000000000000000000000000d72657665727420726561736f6e00000000000000000000000000000000000000", "revert reason", nil},
+		{"4e487b710000000000000000000000000000000000000000000000000000000000000000", "generic panic", nil},
+		{"4e487b7100000000000000000000000000000000000000000000000000000000000000ff", "unknown panic code: 0xff", nil},
 	}
 	for index, c := range cases {
+		index, c := index, c
 		t.Run(fmt.Sprintf("case %d", index), func(t *testing.T) {
+			t.Parallel()
 			got, err := UnpackRevert(common.Hex2Bytes(c.input))
 			if c.expectErr != nil {
 				if err == nil {

accounts/abi/abifuzzer_test.go

@@ -20,20 +20,34 @@ import (
 	"fmt"
 	"reflect"
 	"strings"
+	"testing"
 
-	"github.com/ethereum/go-ethereum/accounts/abi"
 	fuzz "github.com/google/gofuzz"
 )
 
+// TestReplicate can be used to replicate crashers from the fuzzing tests.
+// Just replace testString with the data in .quoted
+func TestReplicate(t *testing.T) {
+	t.Parallel()
+	//t.Skip("Test only useful for reproducing issues")
+	fuzzAbi([]byte("\x20\x20\x20\x20\x20\x20\x20\x20\x80\x00\x00\x00\x20\x20\x20\x20\x00"))
+	//fuzzAbi([]byte("asdfasdfkadsf;lasdf;lasd;lfk"))
+}
+
+// FuzzABI is the main entrypoint for fuzzing
+func FuzzABI(f *testing.F) {
+	f.Fuzz(func(t *testing.T, data []byte) {
+		fuzzAbi(data)
+	})
+}
+
 var (
-	names            = []string{"_name", "name", "NAME", "name_", "__", "_name_", "n"}
-	stateMut         = []string{"", "pure", "view", "payable"}
-	stateMutabilites = []*string{&stateMut[0], &stateMut[1], &stateMut[2], &stateMut[3]}
-	pays             = []string{"", "true", "false"}
-	payables         = []*string{&pays[0], &pays[1]}
-	vNames           = []string{"a", "b", "c", "d", "e", "f", "g"}
-	varNames         = append(vNames, names...)
-	varTypes         = []string{"bool", "address", "bytes", "string",
+	names    = []string{"_name", "name", "NAME", "name_", "__", "_name_", "n"}
+	stateMut = []string{"pure", "view", "payable"}
+	pays     = []string{"true", "false"}
+	vNames   = []string{"a", "b", "c", "d", "e", "f", "g"}
+	varNames = append(vNames, names...)
+	varTypes = []string{"bool", "address", "bytes", "string",
 		"uint8", "int8", "uint8", "int8", "uint16", "int16",
 		"uint24", "int24", "uint32", "int32", "uint40", "int40", "uint48", "int48", "uint56", "int56",
 		"uint64", "int64", "uint72", "int72", "uint80", "int80", "uint88", "int88", "uint96", "int96",
@@ -47,7 +61,7 @@ var (
 		"bytes32", "bytes"}
 )
 
-func unpackPack(abi abi.ABI, method string, input []byte) ([]interface{}, bool) {
+func unpackPack(abi ABI, method string, input []byte) ([]interface{}, bool) {
 	if out, err := abi.Unpack(method, input); err == nil {
 		_, err := abi.Pack(method, out...)
 		if err != nil {
@@ -63,7 +77,7 @@ func unpackPack(abi abi.ABI, method string, input []byte) ([]interface{}, bool)
 	return nil, false
 }
 
-func packUnpack(abi abi.ABI, method string, input *[]interface{}) bool {
+func packUnpack(abi ABI, method string, input *[]interface{}) bool {
 	if packed, err := abi.Pack(method, input); err == nil {
 		outptr := reflect.New(reflect.TypeOf(input))
 		err := abi.UnpackIntoInterface(outptr.Interface(), method, packed)
@@ -79,12 +93,12 @@ func packUnpack(abi abi.ABI, method string, input *[]interface{}) bool {
 	return false
 }
 
-type args struct {
+type arg struct {
 	name string
 	typ  string
 }
 
-func createABI(name string, stateMutability, payable *string, inputs []args) (abi.ABI, error) {
+func createABI(name string, stateMutability, payable *string, inputs []arg) (ABI, error) {
 	sig := fmt.Sprintf(`[{ "type" : "function", "name" : "%v" `, name)
 	if stateMutability != nil {
 		sig += fmt.Sprintf(`, "stateMutability": "%v" `, *stateMutability)
@@ -111,60 +125,55 @@ func createABI(name string, stateMutability, payable *string, inputs []args) (ab
 		sig += "} ]"
 	}
 	sig += `}]`
-
-	return abi.JSON(strings.NewReader(sig))
+	//fmt.Printf("sig: %s\n", sig)
+	return JSON(strings.NewReader(sig))
 }
 
-func runFuzzer(input []byte) int {
-	good := false
-	fuzzer := fuzz.NewFromGoFuzz(input)
-
-	name := names[getUInt(fuzzer)%len(names)]
-	stateM := stateMutabilites[getUInt(fuzzer)%len(stateMutabilites)]
-	payable := payables[getUInt(fuzzer)%len(payables)]
-	maxLen := 5
-	for k := 1; k < maxLen; k++ {
-		var arg []args
-		for i := k; i > 0; i-- {
-			argName := varNames[i]
-			argTyp := varTypes[getUInt(fuzzer)%len(varTypes)]
-			if getUInt(fuzzer)%10 == 0 {
-				argTyp += "[]"
-			} else if getUInt(fuzzer)%10 == 0 {
-				arrayArgs := getUInt(fuzzer)%30 + 1
-				argTyp += fmt.Sprintf("[%d]", arrayArgs)
-			}
-			arg = append(arg, args{
-				name: argName,
-				typ:  argTyp,
-			})
+func fuzzAbi(input []byte) {
+	var (
+		fuzzer    = fuzz.NewFromGoFuzz(input)
+		name      = oneOf(fuzzer, names)
+		stateM    = oneOfOrNil(fuzzer, stateMut)
+		payable   = oneOfOrNil(fuzzer, pays)
+		arguments []arg
+	)
+	for i := 0; i < upTo(fuzzer, 10); i++ {
+		argName := oneOf(fuzzer, varNames)
+		argTyp := oneOf(fuzzer, varTypes)
+		switch upTo(fuzzer, 10) {
+		case 0: // 10% chance to make it a slice
+			argTyp += "[]"
+		case 1: // 10% chance to make it an array
+			argTyp += fmt.Sprintf("[%d]", 1+upTo(fuzzer, 30))
+		default:
 		}
-		abi, err := createABI(name, stateM, payable, arg)
-		if err != nil {
-			continue
-		}
-		structs, b := unpackPack(abi, name, input)
-		c := packUnpack(abi, name, &structs)
-		good = good || b || c
+		arguments = append(arguments, arg{name: argName, typ: argTyp})
 	}
-	if good {
-		return 1
+	abi, err := createABI(name, stateM, payable, arguments)
+	if err != nil {
+		//fmt.Printf("err: %v\n", err)
+		panic(err)
 	}
-	return 0
+	structs, _ := unpackPack(abi, name, input)
+	_ = packUnpack(abi, name, &structs)
 }
 
-func Fuzz(input []byte) int {
-	return runFuzzer(input)
-}
-
-func getUInt(fuzzer *fuzz.Fuzzer) int {
+func upTo(fuzzer *fuzz.Fuzzer, max int) int {
 	var i int
 	fuzzer.Fuzz(&i)
 	if i < 0 {
-		i = -i
-		if i < 0 {
-			return 0
-		}
+		return (-1 - i) % max
 	}
-	return i
+	return i % max
+}
+
+func oneOf(fuzzer *fuzz.Fuzzer, options []string) string {
+	return options[upTo(fuzzer, len(options))]
+}
+
+func oneOfOrNil(fuzzer *fuzz.Fuzzer, options []string) *string {
+	if i := upTo(fuzzer, len(options)+1); i < len(options) {
+		return &options[i]
+	}
+	return nil
 }

accounts/abi/argument.go

@@ -80,7 +80,7 @@ func (arguments Arguments) isTuple() bool {
 func (arguments Arguments) Unpack(data []byte) ([]interface{}, error) {
 	if len(data) == 0 {
 		if len(arguments.NonIndexed()) != 0 {
-			return nil, errors.New("abi: attempting to unmarshall an empty string while arguments are expected")
+			return nil, errors.New("abi: attempting to unmarshal an empty string while arguments are expected")
 		}
 		return make([]interface{}, 0), nil
 	}
@@ -95,7 +95,7 @@ func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte)
 	}
 	if len(data) == 0 {
 		if len(arguments.NonIndexed()) != 0 {
-			return errors.New("abi: attempting to unmarshall an empty string while arguments are expected")
+			return errors.New("abi: attempting to unmarshal an empty string while arguments are expected")
 		}
 		return nil // Nothing to unmarshal, return
 	}
@@ -127,7 +127,7 @@ func (arguments Arguments) Copy(v interface{}, values []interface{}) error {
 	return arguments.copyAtomic(v, values[0])
 }
 
-// unpackAtomic unpacks ( hexdata -> go ) a single value
+// copyAtomic copies ( hexdata -> go ) a single value
 func (arguments Arguments) copyAtomic(v interface{}, marshalledValues interface{}) error {
 	dst := reflect.ValueOf(v).Elem()
 	src := reflect.ValueOf(marshalledValues)

accounts/abi/bind/auth.go

@@ -56,7 +56,7 @@ func NewTransactor(keyin io.Reader, passphrase string) (*TransactOpts, error) {
 }
 
 // NewKeyStoreTransactor is a utility method to easily create a transaction signer from
-// an decrypted key from a keystore.
+// a decrypted key from a keystore.
 //
 // Deprecated: Use NewKeyStoreTransactorWithChainID instead.
 func NewKeyStoreTransactor(keystore *keystore.KeyStore, account accounts.Account) (*TransactOpts, error) {
@@ -117,7 +117,7 @@ func NewTransactorWithChainID(keyin io.Reader, passphrase string, chainID *big.I
 }
 
 // NewKeyStoreTransactorWithChainID is a utility method to easily create a transaction signer from
-// an decrypted key from a keystore.
+// a decrypted key from a keystore.
 func NewKeyStoreTransactorWithChainID(keystore *keystore.KeyStore, account accounts.Account, chainID *big.Int) (*TransactOpts, error) {
 	if chainID == nil {
 		return nil, ErrNoChainID
@@ -142,10 +142,10 @@ func NewKeyStoreTransactorWithChainID(keystore *keystore.KeyStore, account accou
 // NewKeyedTransactorWithChainID is a utility method to easily create a transaction signer
 // from a single private key.
 func NewKeyedTransactorWithChainID(key *ecdsa.PrivateKey, chainID *big.Int) (*TransactOpts, error) {
-	keyAddr := crypto.PubkeyToAddress(key.PublicKey)
 	if chainID == nil {
 		return nil, ErrNoChainID
 	}
+	keyAddr := crypto.PubkeyToAddress(key.PublicKey)
 	signer := types.LatestSignerForChainID(chainID)
 	return &TransactOpts{
 		From: keyAddr,

accounts/abi/bind/backend.go

@@ -29,13 +29,17 @@ import (
 var (
 	// ErrNoCode is returned by call and transact operations for which the requested
 	// recipient contract to operate on does not exist in the state db or does not
-	// have any code associated with it (i.e. suicided).
+	// have any code associated with it (i.e. self-destructed).
 	ErrNoCode = errors.New("no contract code at given address")
 
 	// ErrNoPendingState is raised when attempting to perform a pending state action
 	// on a backend that doesn't implement PendingContractCaller.
 	ErrNoPendingState = errors.New("backend does not support pending state")
 
+	// ErrNoBlockHashState is raised when attempting to perform a block hash action
+	// on a backend that doesn't implement BlockHashContractCaller.
+	ErrNoBlockHashState = errors.New("backend does not support block hash state")
+
 	// ErrNoCodeAfterDeploy is returned by WaitDeployed if contract creation leaves
 	// an empty contract behind.
 	ErrNoCodeAfterDeploy = errors.New("no contract code after deployment")
@@ -64,11 +68,27 @@ type PendingContractCaller interface {
 	PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error)
 }
 
+// BlockHashContractCaller defines methods to perform contract calls on a specific block hash.
+// Call will try to discover this interface when access to a block by hash is requested.
+// If the backend does not support the block hash state, Call returns ErrNoBlockHashState.
+type BlockHashContractCaller interface {
+	// CodeAtHash returns the code of the given account in the state at the specified block hash.
+	CodeAtHash(ctx context.Context, contract common.Address, blockHash common.Hash) ([]byte, error)
+
+	// CallContractAtHash executes an Ethereum contract call against the state at the specified block hash.
+	CallContractAtHash(ctx context.Context, call ethereum.CallMsg, blockHash common.Hash) ([]byte, error)
+}
+
 // ContractTransactor defines the methods needed to allow operating with a contract
 // on a write only basis. Besides the transacting method, the remainder are helpers
 // used when the user does not provide some needed values, but rather leaves it up
 // to the transactor to decide.
 type ContractTransactor interface {
+	ethereum.GasEstimator
+	ethereum.GasPricer
+	ethereum.GasPricer1559
+	ethereum.TransactionSender
+
 	// HeaderByNumber returns a block header from the current canonical chain. If
 	// number is nil, the latest known header is returned.
 	HeaderByNumber(ctx context.Context, number *big.Int) (*types.Header, error)
@@ -78,38 +98,6 @@ type ContractTransactor interface {
 
 	// PendingNonceAt retrieves the current pending nonce associated with an account.
 	PendingNonceAt(ctx context.Context, account common.Address) (uint64, error)
-
-	// SuggestGasPrice retrieves the currently suggested gas price to allow a timely
-	// execution of a transaction.
-	SuggestGasPrice(ctx context.Context) (*big.Int, error)
-
-	// SuggestGasTipCap retrieves the currently suggested 1559 priority fee to allow
-	// a timely execution of a transaction.
-	SuggestGasTipCap(ctx context.Context) (*big.Int, error)
-
-	// EstimateGas tries to estimate the gas needed to execute a specific
-	// transaction based on the current pending state of the backend blockchain.
-	// There is no guarantee that this is the true gas limit requirement as other
-	// transactions may be added or removed by miners, but it should provide a basis
-	// for setting a reasonable default.
-	EstimateGas(ctx context.Context, call ethereum.CallMsg) (gas uint64, err error)
-
-	// SendTransaction injects the transaction into the pending pool for execution.
-	SendTransaction(ctx context.Context, tx *types.Transaction) error
-}
-
-// ContractFilterer defines the methods needed to access log events using one-off
-// queries or continuous event subscriptions.
-type ContractFilterer interface {
-	// FilterLogs executes a log filter operation, blocking during execution and
-	// returning all the results in one batch.
-	//
-	// TODO(karalabe): Deprecate when the subscription one can return past data too.
-	FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error)
-
-	// SubscribeFilterLogs creates a background log filtering operation, returning
-	// a subscription immediately, which can be used to stream the found events.
-	SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error)
 }
 
 // DeployBackend wraps the operations needed by WaitMined and WaitDeployed.
@@ -118,6 +106,12 @@ type DeployBackend interface {
 	CodeAt(ctx context.Context, account common.Address, blockNumber *big.Int) ([]byte, error)
 }
 
+// ContractFilterer defines the methods needed to access log events using one-off
+// queries or continuous event subscriptions.
+type ContractFilterer interface {
+	ethereum.LogFilterer
+}
+
 // ContractBackend defines the methods needed to work with contracts on a read-write basis.
 type ContractBackend interface {
 	ContractCaller

accounts/abi/bind/backends/simulated.go

@@ -18,921 +18,35 @@ package backends
 
 import (
 	"context"
-	"errors"
-	"fmt"
-	"math/big"
-	"sync"
-	"time"
 
-	"github.com/ethereum/go-ethereum"
-	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/accounts/abi/bind"
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/common/hexutil"
-	"github.com/ethereum/go-ethereum/common/math"
-	"github.com/ethereum/go-ethereum/consensus/ethash"
-	"github.com/ethereum/go-ethereum/core"
-	"github.com/ethereum/go-ethereum/core/bloombits"
-	"github.com/ethereum/go-ethereum/core/rawdb"
-	"github.com/ethereum/go-ethereum/core/state"
 	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/core/vm"
-	"github.com/ethereum/go-ethereum/eth/filters"
-	"github.com/ethereum/go-ethereum/ethdb"
-	"github.com/ethereum/go-ethereum/event"
-	"github.com/ethereum/go-ethereum/log"
-	"github.com/ethereum/go-ethereum/params"
-	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/ethereum/go-ethereum/ethclient/simulated"
 )
 
-// This nil assignment ensures at compile time that SimulatedBackend implements bind.ContractBackend.
-var _ bind.ContractBackend = (*SimulatedBackend)(nil)
-
-var (
-	errBlockNumberUnsupported  = errors.New("simulatedBackend cannot access blocks other than the latest block")
-	errBlockDoesNotExist       = errors.New("block does not exist in blockchain")
-	errTransactionDoesNotExist = errors.New("transaction does not exist")
-)
-
-// SimulatedBackend implements bind.ContractBackend, simulating a blockchain in
-// the background. Its main purpose is to allow for easy testing of contract bindings.
-// Simulated backend implements the following interfaces:
-// ChainReader, ChainStateReader, ContractBackend, ContractCaller, ContractFilterer, ContractTransactor,
-// DeployBackend, GasEstimator, GasPricer, LogFilterer, PendingContractCaller, TransactionReader, and TransactionSender
+// SimulatedBackend is a simulated blockchain.
+// Deprecated: use package github.com/ethereum/go-ethereum/ethclient/simulated instead.
 type SimulatedBackend struct {
-	database   ethdb.Database   // In memory database to store our testing data
-	blockchain *core.BlockChain // Ethereum blockchain to handle the consensus
-
-	mu              sync.Mutex
-	pendingBlock    *types.Block   // Currently pending block that will be imported on request
-	pendingState    *state.StateDB // Currently pending state that will be the active on request
-	pendingReceipts types.Receipts // Currently receipts for the pending block
-
-	events       *filters.EventSystem  // for filtering log events live
-	filterSystem *filters.FilterSystem // for filtering database logs
-
-	config *params.ChainConfig
+	*simulated.Backend
+	simulated.Client
 }
 
-// NewSimulatedBackendWithDatabase creates a new binding backend based on the given database
-// and uses a simulated blockchain for testing purposes.
-// A simulated backend always uses chainID 1337.
-func NewSimulatedBackendWithDatabase(database ethdb.Database, alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
-	genesis := core.Genesis{
-		Config:   params.AllEthashProtocolChanges,
-		GasLimit: gasLimit,
-		Alloc:    alloc,
-	}
-	blockchain, _ := core.NewBlockChain(database, nil, &genesis, nil, ethash.NewFaker(), vm.Config{}, nil, nil)
-
-	backend := &SimulatedBackend{
-		database:   database,
-		blockchain: blockchain,
-		config:     genesis.Config,
-	}
-
-	filterBackend := &filterBackend{database, blockchain, backend}
-	backend.filterSystem = filters.NewFilterSystem(filterBackend, filters.Config{})
-	backend.events = filters.NewEventSystem(backend.filterSystem, false)
-
-	header := backend.blockchain.CurrentBlock()
-	block := backend.blockchain.GetBlock(header.Hash(), header.Number.Uint64())
-
-	backend.rollback(block)
-	return backend
+// Fork sets the head to a new block, which is based on the provided parentHash.
+func (b *SimulatedBackend) Fork(ctx context.Context, parentHash common.Hash) error {
+	return b.Backend.Fork(parentHash)
 }
 
 // NewSimulatedBackend creates a new binding backend using a simulated blockchain
 // for testing purposes.
+//
 // A simulated backend always uses chainID 1337.
-func NewSimulatedBackend(alloc core.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
-	return NewSimulatedBackendWithDatabase(rawdb.NewMemoryDatabase(), alloc, gasLimit)
-}
-
-// Close terminates the underlying blockchain's update loop.
-func (b *SimulatedBackend) Close() error {
-	b.blockchain.Stop()
-	return nil
-}
-
-// Commit imports all the pending transactions as a single block and starts a
-// fresh new state.
-func (b *SimulatedBackend) Commit() common.Hash {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if _, err := b.blockchain.InsertChain([]*types.Block{b.pendingBlock}); err != nil {
-		panic(err) // This cannot happen unless the simulator is wrong, fail in that case
-	}
-	blockHash := b.pendingBlock.Hash()
-
-	// Using the last inserted block here makes it possible to build on a side
-	// chain after a fork.
-	b.rollback(b.pendingBlock)
-
-	return blockHash
-}
-
-// Rollback aborts all pending transactions, reverting to the last committed state.
-func (b *SimulatedBackend) Rollback() {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	header := b.blockchain.CurrentBlock()
-	block := b.blockchain.GetBlock(header.Hash(), header.Number.Uint64())
-
-	b.rollback(block)
-}
-
-func (b *SimulatedBackend) rollback(parent *types.Block) {
-	blocks, _ := core.GenerateChain(b.config, parent, ethash.NewFaker(), b.database, 1, func(int, *core.BlockGen) {})
-
-	b.pendingBlock = blocks[0]
-	b.pendingState, _ = state.New(b.pendingBlock.Root(), b.blockchain.StateCache(), nil)
-}
-
-// Fork creates a side-chain that can be used to simulate reorgs.
 //
-// This function should be called with the ancestor block where the new side
-// chain should be started. Transactions (old and new) can then be applied on
-// top and Commit-ed.
-//
-// Note, the side-chain will only become canonical (and trigger the events) when
-// it becomes longer. Until then CallContract will still operate on the current
-// canonical chain.
-//
-// There is a % chance that the side chain becomes canonical at the same length
-// to simulate live network behavior.
-func (b *SimulatedBackend) Fork(ctx context.Context, parent common.Hash) error {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if len(b.pendingBlock.Transactions()) != 0 {
-		return errors.New("pending block dirty")
-	}
-	block, err := b.blockByHash(ctx, parent)
-	if err != nil {
-		return err
-	}
-	b.rollback(block)
-	return nil
-}
-
-// stateByBlockNumber retrieves a state by a given blocknumber.
-func (b *SimulatedBackend) stateByBlockNumber(ctx context.Context, blockNumber *big.Int) (*state.StateDB, error) {
-	if blockNumber == nil || blockNumber.Cmp(b.blockchain.CurrentBlock().Number) == 0 {
-		return b.blockchain.State()
-	}
-	block, err := b.blockByNumber(ctx, blockNumber)
-	if err != nil {
-		return nil, err
-	}
-	return b.blockchain.StateAt(block.Root())
-}
-
-// CodeAt returns the code associated with a certain account in the blockchain.
-func (b *SimulatedBackend) CodeAt(ctx context.Context, contract common.Address, blockNumber *big.Int) ([]byte, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
-	if err != nil {
-		return nil, err
-	}
-
-	return stateDB.GetCode(contract), nil
-}
-
-// BalanceAt returns the wei balance of a certain account in the blockchain.
-func (b *SimulatedBackend) BalanceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (*big.Int, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
-	if err != nil {
-		return nil, err
-	}
-
-	return stateDB.GetBalance(contract), nil
-}
-
-// NonceAt returns the nonce of a certain account in the blockchain.
-func (b *SimulatedBackend) NonceAt(ctx context.Context, contract common.Address, blockNumber *big.Int) (uint64, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
-	if err != nil {
-		return 0, err
-	}
-
-	return stateDB.GetNonce(contract), nil
-}
-
-// StorageAt returns the value of key in the storage of an account in the blockchain.
-func (b *SimulatedBackend) StorageAt(ctx context.Context, contract common.Address, key common.Hash, blockNumber *big.Int) ([]byte, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	stateDB, err := b.stateByBlockNumber(ctx, blockNumber)
-	if err != nil {
-		return nil, err
-	}
-
-	val := stateDB.GetState(contract, key)
-	return val[:], nil
-}
-
-// TransactionReceipt returns the receipt of a transaction.
-func (b *SimulatedBackend) TransactionReceipt(ctx context.Context, txHash common.Hash) (*types.Receipt, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	receipt, _, _, _ := rawdb.ReadReceipt(b.database, txHash, b.config)
-	if receipt == nil {
-		return nil, ethereum.NotFound
-	}
-	return receipt, nil
-}
-
-// TransactionByHash checks the pool of pending transactions in addition to the
-// blockchain. The isPending return value indicates whether the transaction has been
-// mined yet. Note that the transaction may not be part of the canonical chain even if
-// it's not pending.
-func (b *SimulatedBackend) TransactionByHash(ctx context.Context, txHash common.Hash) (*types.Transaction, bool, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	tx := b.pendingBlock.Transaction(txHash)
-	if tx != nil {
-		return tx, true, nil
-	}
-	tx, _, _, _ = rawdb.ReadTransaction(b.database, txHash)
-	if tx != nil {
-		return tx, false, nil
-	}
-	return nil, false, ethereum.NotFound
-}
-
-// BlockByHash retrieves a block based on the block hash.
-func (b *SimulatedBackend) BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	return b.blockByHash(ctx, hash)
-}
-
-// blockByHash retrieves a block based on the block hash without Locking.
-func (b *SimulatedBackend) blockByHash(ctx context.Context, hash common.Hash) (*types.Block, error) {
-	if hash == b.pendingBlock.Hash() {
-		return b.pendingBlock, nil
-	}
-
-	block := b.blockchain.GetBlockByHash(hash)
-	if block != nil {
-		return block, nil
-	}
-
-	return nil, errBlockDoesNotExist
-}
-
-// BlockByNumber retrieves a block from the database by number, caching it
-// (associated with its hash) if found.
-func (b *SimulatedBackend) BlockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	return b.blockByNumber(ctx, number)
-}
-
-// blockByNumber retrieves a block from the database by number, caching it
-// (associated with its hash) if found without Lock.
-func (b *SimulatedBackend) blockByNumber(ctx context.Context, number *big.Int) (*types.Block, error) {
-	if number == nil || number.Cmp(b.pendingBlock.Number()) == 0 {
-		return b.blockByHash(ctx, b.blockchain.CurrentBlock().Hash())
-	}
-
-	block := b.blockchain.GetBlockByNumber(uint64(number.Int64()))
-	if block == nil {
-		return nil, errBlockDoesNotExist
-	}
-
-	return block, nil
-}
-
-// HeaderByHash returns a block header from the current canonical chain.
-func (b *SimulatedBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if hash == b.pendingBlock.Hash() {
-		return b.pendingBlock.Header(), nil
-	}
-
-	header := b.blockchain.GetHeaderByHash(hash)
-	if header == nil {
-		return nil, errBlockDoesNotExist
-	}
-
-	return header, nil
-}
-
-// HeaderByNumber returns a block header from the current canonical chain. If number is
-// nil, the latest known header is returned.
-func (b *SimulatedBackend) HeaderByNumber(ctx context.Context, block *big.Int) (*types.Header, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if block == nil || block.Cmp(b.pendingBlock.Number()) == 0 {
-		return b.blockchain.CurrentHeader(), nil
-	}
-
-	return b.blockchain.GetHeaderByNumber(uint64(block.Int64())), nil
-}
-
-// TransactionCount returns the number of transactions in a given block.
-func (b *SimulatedBackend) TransactionCount(ctx context.Context, blockHash common.Hash) (uint, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if blockHash == b.pendingBlock.Hash() {
-		return uint(b.pendingBlock.Transactions().Len()), nil
-	}
-
-	block := b.blockchain.GetBlockByHash(blockHash)
-	if block == nil {
-		return uint(0), errBlockDoesNotExist
-	}
-
-	return uint(block.Transactions().Len()), nil
-}
-
-// TransactionInBlock returns the transaction for a specific block at a specific index.
-func (b *SimulatedBackend) TransactionInBlock(ctx context.Context, blockHash common.Hash, index uint) (*types.Transaction, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if blockHash == b.pendingBlock.Hash() {
-		transactions := b.pendingBlock.Transactions()
-		if uint(len(transactions)) < index+1 {
-			return nil, errTransactionDoesNotExist
-		}
-
-		return transactions[index], nil
-	}
-
-	block := b.blockchain.GetBlockByHash(blockHash)
-	if block == nil {
-		return nil, errBlockDoesNotExist
-	}
-
-	transactions := block.Transactions()
-	if uint(len(transactions)) < index+1 {
-		return nil, errTransactionDoesNotExist
-	}
-
-	return transactions[index], nil
-}
-
-// PendingCodeAt returns the code associated with an account in the pending state.
-func (b *SimulatedBackend) PendingCodeAt(ctx context.Context, contract common.Address) ([]byte, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	return b.pendingState.GetCode(contract), nil
-}
-
-func newRevertError(result *core.ExecutionResult) *revertError {
-	reason, errUnpack := abi.UnpackRevert(result.Revert())
-	err := errors.New("execution reverted")
-	if errUnpack == nil {
-		err = fmt.Errorf("execution reverted: %v", reason)
-	}
-	return &revertError{
-		error:  err,
-		reason: hexutil.Encode(result.Revert()),
+// Deprecated: please use simulated.Backend from package
+// github.com/ethereum/go-ethereum/ethclient/simulated instead.
+func NewSimulatedBackend(alloc types.GenesisAlloc, gasLimit uint64) *SimulatedBackend {
+	b := simulated.NewBackend(alloc, simulated.WithBlockGasLimit(gasLimit))
+	return &SimulatedBackend{
+		Backend: b,
+		Client:  b.Client(),
 	}
 }
-
-// revertError is an API error that encompasses an EVM revert with JSON error
-// code and a binary data blob.
-type revertError struct {
-	error
-	reason string // revert reason hex encoded
-}
-
-// ErrorCode returns the JSON error code for a revert.
-// See: https://github.com/ethereum/wiki/wiki/JSON-RPC-Error-Codes-Improvement-Proposal
-func (e *revertError) ErrorCode() int {
-	return 3
-}
-
-// ErrorData returns the hex encoded revert reason.
-func (e *revertError) ErrorData() interface{} {
-	return e.reason
-}
-
-// CallContract executes a contract call.
-func (b *SimulatedBackend) CallContract(ctx context.Context, call ethereum.CallMsg, blockNumber *big.Int) ([]byte, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if blockNumber != nil && blockNumber.Cmp(b.blockchain.CurrentBlock().Number) != 0 {
-		return nil, errBlockNumberUnsupported
-	}
-	stateDB, err := b.blockchain.State()
-	if err != nil {
-		return nil, err
-	}
-	res, err := b.callContract(ctx, call, b.blockchain.CurrentBlock(), stateDB)
-	if err != nil {
-		return nil, err
-	}
-	// If the result contains a revert reason, try to unpack and return it.
-	if len(res.Revert()) > 0 {
-		return nil, newRevertError(res)
-	}
-	return res.Return(), res.Err
-}
-
-// PendingCallContract executes a contract call on the pending state.
-func (b *SimulatedBackend) PendingCallContract(ctx context.Context, call ethereum.CallMsg) ([]byte, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-	defer b.pendingState.RevertToSnapshot(b.pendingState.Snapshot())
-
-	res, err := b.callContract(ctx, call, b.pendingBlock.Header(), b.pendingState)
-	if err != nil {
-		return nil, err
-	}
-	// If the result contains a revert reason, try to unpack and return it.
-	if len(res.Revert()) > 0 {
-		return nil, newRevertError(res)
-	}
-	return res.Return(), res.Err
-}
-
-// PendingNonceAt implements PendingStateReader.PendingNonceAt, retrieving
-// the nonce currently pending for the account.
-func (b *SimulatedBackend) PendingNonceAt(ctx context.Context, account common.Address) (uint64, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	return b.pendingState.GetOrNewStateObject(account).Nonce(), nil
-}
-
-// SuggestGasPrice implements ContractTransactor.SuggestGasPrice. Since the simulated
-// chain doesn't have miners, we just return a gas price of 1 for any call.
-func (b *SimulatedBackend) SuggestGasPrice(ctx context.Context) (*big.Int, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if b.pendingBlock.Header().BaseFee != nil {
-		return b.pendingBlock.Header().BaseFee, nil
-	}
-	return big.NewInt(1), nil
-}
-
-// SuggestGasTipCap implements ContractTransactor.SuggestGasTipCap. Since the simulated
-// chain doesn't have miners, we just return a gas tip of 1 for any call.
-func (b *SimulatedBackend) SuggestGasTipCap(ctx context.Context) (*big.Int, error) {
-	return big.NewInt(1), nil
-}
-
-// EstimateGas executes the requested code against the currently pending block/state and
-// returns the used amount of gas.
-func (b *SimulatedBackend) EstimateGas(ctx context.Context, call ethereum.CallMsg) (uint64, error) {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	// Determine the lowest and highest possible gas limits to binary search in between
-	var (
-		lo  uint64 = params.TxGas - 1
-		hi  uint64
-		cap uint64
-	)
-	if call.Gas >= params.TxGas {
-		hi = call.Gas
-	} else {
-		hi = b.pendingBlock.GasLimit()
-	}
-	// Normalize the max fee per gas the call is willing to spend.
-	var feeCap *big.Int
-	if call.GasPrice != nil && (call.GasFeeCap != nil || call.GasTipCap != nil) {
-		return 0, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
-	} else if call.GasPrice != nil {
-		feeCap = call.GasPrice
-	} else if call.GasFeeCap != nil {
-		feeCap = call.GasFeeCap
-	} else {
-		feeCap = common.Big0
-	}
-	// Recap the highest gas allowance with account's balance.
-	if feeCap.BitLen() != 0 {
-		balance := b.pendingState.GetBalance(call.From) // from can't be nil
-		available := new(big.Int).Set(balance)
-		if call.Value != nil {
-			if call.Value.Cmp(available) >= 0 {
-				return 0, core.ErrInsufficientFundsForTransfer
-			}
-			available.Sub(available, call.Value)
-		}
-		allowance := new(big.Int).Div(available, feeCap)
-		if allowance.IsUint64() && hi > allowance.Uint64() {
-			transfer := call.Value
-			if transfer == nil {
-				transfer = new(big.Int)
-			}
-			log.Warn("Gas estimation capped by limited funds", "original", hi, "balance", balance,
-				"sent", transfer, "feecap", feeCap, "fundable", allowance)
-			hi = allowance.Uint64()
-		}
-	}
-	cap = hi
-
-	// Create a helper to check if a gas allowance results in an executable transaction
-	executable := func(gas uint64) (bool, *core.ExecutionResult, error) {
-		call.Gas = gas
-
-		snapshot := b.pendingState.Snapshot()
-		res, err := b.callContract(ctx, call, b.pendingBlock.Header(), b.pendingState)
-		b.pendingState.RevertToSnapshot(snapshot)
-
-		if err != nil {
-			if errors.Is(err, core.ErrIntrinsicGas) {
-				return true, nil, nil // Special case, raise gas limit
-			}
-			return true, nil, err // Bail out
-		}
-		return res.Failed(), res, nil
-	}
-	// Execute the binary search and hone in on an executable gas limit
-	for lo+1 < hi {
-		mid := (hi + lo) / 2
-		failed, _, err := executable(mid)
-
-		// If the error is not nil(consensus error), it means the provided message
-		// call or transaction will never be accepted no matter how much gas it is
-		// assigned. Return the error directly, don't struggle any more
-		if err != nil {
-			return 0, err
-		}
-		if failed {
-			lo = mid
-		} else {
-			hi = mid
-		}
-	}
-	// Reject the transaction as invalid if it still fails at the highest allowance
-	if hi == cap {
-		failed, result, err := executable(hi)
-		if err != nil {
-			return 0, err
-		}
-		if failed {
-			if result != nil && result.Err != vm.ErrOutOfGas {
-				if len(result.Revert()) > 0 {
-					return 0, newRevertError(result)
-				}
-				return 0, result.Err
-			}
-			// Otherwise, the specified gas cap is too low
-			return 0, fmt.Errorf("gas required exceeds allowance (%d)", cap)
-		}
-	}
-	return hi, nil
-}
-
-// callContract implements common code between normal and pending contract calls.
-// state is modified during execution, make sure to copy it if necessary.
-func (b *SimulatedBackend) callContract(ctx context.Context, call ethereum.CallMsg, header *types.Header, stateDB *state.StateDB) (*core.ExecutionResult, error) {
-	// Gas prices post 1559 need to be initialized
-	if call.GasPrice != nil && (call.GasFeeCap != nil || call.GasTipCap != nil) {
-		return nil, errors.New("both gasPrice and (maxFeePerGas or maxPriorityFeePerGas) specified")
-	}
-	head := b.blockchain.CurrentHeader()
-	if !b.blockchain.Config().IsLondon(head.Number) {
-		// If there's no basefee, then it must be a non-1559 execution
-		if call.GasPrice == nil {
-			call.GasPrice = new(big.Int)
-		}
-		call.GasFeeCap, call.GasTipCap = call.GasPrice, call.GasPrice
-	} else {
-		// A basefee is provided, necessitating 1559-type execution
-		if call.GasPrice != nil {
-			// User specified the legacy gas field, convert to 1559 gas typing
-			call.GasFeeCap, call.GasTipCap = call.GasPrice, call.GasPrice
-		} else {
-			// User specified 1559 gas fields (or none), use those
-			if call.GasFeeCap == nil {
-				call.GasFeeCap = new(big.Int)
-			}
-			if call.GasTipCap == nil {
-				call.GasTipCap = new(big.Int)
-			}
-			// Backfill the legacy gasPrice for EVM execution, unless we're all zeroes
-			call.GasPrice = new(big.Int)
-			if call.GasFeeCap.BitLen() > 0 || call.GasTipCap.BitLen() > 0 {
-				call.GasPrice = math.BigMin(new(big.Int).Add(call.GasTipCap, head.BaseFee), call.GasFeeCap)
-			}
-		}
-	}
-	// Ensure message is initialized properly.
-	if call.Gas == 0 {
-		call.Gas = 50000000
-	}
-	if call.Value == nil {
-		call.Value = new(big.Int)
-	}
-	// Set infinite balance to the fake caller account.
-	from := stateDB.GetOrNewStateObject(call.From)
-	from.SetBalance(math.MaxBig256)
-	// Execute the call.
-	msg := callMsg{call}
-
-	txContext := core.NewEVMTxContext(msg)
-	evmContext := core.NewEVMBlockContext(header, b.blockchain, nil)
-	// Create a new environment which holds all relevant information
-	// about the transaction and calling mechanisms.
-	vmEnv := vm.NewEVM(evmContext, txContext, stateDB, b.config, vm.Config{NoBaseFee: true})
-	gasPool := new(core.GasPool).AddGas(math.MaxUint64)
-
-	return core.NewStateTransition(vmEnv, msg, gasPool).TransitionDb()
-}
-
-// SendTransaction updates the pending block to include the given transaction.
-func (b *SimulatedBackend) SendTransaction(ctx context.Context, tx *types.Transaction) error {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	// Get the last block
-	block, err := b.blockByHash(ctx, b.pendingBlock.ParentHash())
-	if err != nil {
-		return fmt.Errorf("could not fetch parent")
-	}
-	// Check transaction validity
-	signer := types.MakeSigner(b.blockchain.Config(), block.Number())
-	sender, err := types.Sender(signer, tx)
-	if err != nil {
-		return fmt.Errorf("invalid transaction: %v", err)
-	}
-	nonce := b.pendingState.GetNonce(sender)
-	if tx.Nonce() != nonce {
-		return fmt.Errorf("invalid transaction nonce: got %d, want %d", tx.Nonce(), nonce)
-	}
-	// Include tx in chain
-	blocks, receipts := core.GenerateChain(b.config, block, ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
-		for _, tx := range b.pendingBlock.Transactions() {
-			block.AddTxWithChain(b.blockchain, tx)
-		}
-		block.AddTxWithChain(b.blockchain, tx)
-	})
-	stateDB, _ := b.blockchain.State()
-
-	b.pendingBlock = blocks[0]
-	b.pendingState, _ = state.New(b.pendingBlock.Root(), stateDB.Database(), nil)
-	b.pendingReceipts = receipts[0]
-	return nil
-}
-
-// FilterLogs executes a log filter operation, blocking during execution and
-// returning all the results in one batch.
-//
-// TODO(karalabe): Deprecate when the subscription one can return past data too.
-func (b *SimulatedBackend) FilterLogs(ctx context.Context, query ethereum.FilterQuery) ([]types.Log, error) {
-	var filter *filters.Filter
-	if query.BlockHash != nil {
-		// Block filter requested, construct a single-shot filter
-		filter = b.filterSystem.NewBlockFilter(*query.BlockHash, query.Addresses, query.Topics)
-	} else {
-		// Initialize unset filter boundaries to run from genesis to chain head
-		from := int64(0)
-		if query.FromBlock != nil {
-			from = query.FromBlock.Int64()
-		}
-		to := int64(-1)
-		if query.ToBlock != nil {
-			to = query.ToBlock.Int64()
-		}
-		// Construct the range filter
-		filter = b.filterSystem.NewRangeFilter(from, to, query.Addresses, query.Topics)
-	}
-	// Run the filter and return all the logs
-	logs, err := filter.Logs(ctx)
-	if err != nil {
-		return nil, err
-	}
-	res := make([]types.Log, len(logs))
-	for i, nLog := range logs {
-		res[i] = *nLog
-	}
-	return res, nil
-}
-
-// SubscribeFilterLogs creates a background log filtering operation, returning a
-// subscription immediately, which can be used to stream the found events.
-func (b *SimulatedBackend) SubscribeFilterLogs(ctx context.Context, query ethereum.FilterQuery, ch chan<- types.Log) (ethereum.Subscription, error) {
-	// Subscribe to contract events
-	sink := make(chan []*types.Log)
-
-	sub, err := b.events.SubscribeLogs(query, sink)
-	if err != nil {
-		return nil, err
-	}
-	// Since we're getting logs in batches, we need to flatten them into a plain stream
-	return event.NewSubscription(func(quit <-chan struct{}) error {
-		defer sub.Unsubscribe()
-		for {
-			select {
-			case logs := <-sink:
-				for _, nlog := range logs {
-					select {
-					case ch <- *nlog:
-					case err := <-sub.Err():
-						return err
-					case <-quit:
-						return nil
-					}
-				}
-			case err := <-sub.Err():
-				return err
-			case <-quit:
-				return nil
-			}
-		}
-	}), nil
-}
-
-// SubscribeNewHead returns an event subscription for a new header.
-func (b *SimulatedBackend) SubscribeNewHead(ctx context.Context, ch chan<- *types.Header) (ethereum.Subscription, error) {
-	// subscribe to a new head
-	sink := make(chan *types.Header)
-	sub := b.events.SubscribeNewHeads(sink)
-
-	return event.NewSubscription(func(quit <-chan struct{}) error {
-		defer sub.Unsubscribe()
-		for {
-			select {
-			case head := <-sink:
-				select {
-				case ch <- head:
-				case err := <-sub.Err():
-					return err
-				case <-quit:
-					return nil
-				}
-			case err := <-sub.Err():
-				return err
-			case <-quit:
-				return nil
-			}
-		}
-	}), nil
-}
-
-// AdjustTime adds a time shift to the simulated clock.
-// It can only be called on empty blocks.
-func (b *SimulatedBackend) AdjustTime(adjustment time.Duration) error {
-	b.mu.Lock()
-	defer b.mu.Unlock()
-
-	if len(b.pendingBlock.Transactions()) != 0 {
-		return errors.New("Could not adjust time on non-empty block")
-	}
-	// Get the last block
-	block := b.blockchain.GetBlockByHash(b.pendingBlock.ParentHash())
-	if block == nil {
-		return fmt.Errorf("could not find parent")
-	}
-
-	blocks, _ := core.GenerateChain(b.config, block, ethash.NewFaker(), b.database, 1, func(number int, block *core.BlockGen) {
-		block.OffsetTime(int64(adjustment.Seconds()))
-	})
-	stateDB, _ := b.blockchain.State()
-
-	b.pendingBlock = blocks[0]
-	b.pendingState, _ = state.New(b.pendingBlock.Root(), stateDB.Database(), nil)
-
-	return nil
-}
-
-// Blockchain returns the underlying blockchain.
-func (b *SimulatedBackend) Blockchain() *core.BlockChain {
-	return b.blockchain
-}
-
-// callMsg implements core.Message to allow passing it as a transaction simulator.
-type callMsg struct {
-	ethereum.CallMsg
-}
-
-func (m callMsg) From() common.Address         { return m.CallMsg.From }
-func (m callMsg) Nonce() uint64                { return 0 }
-func (m callMsg) IsFake() bool                 { return true }
-func (m callMsg) To() *common.Address          { return m.CallMsg.To }
-func (m callMsg) GasPrice() *big.Int           { return m.CallMsg.GasPrice }
-func (m callMsg) GasFeeCap() *big.Int          { return m.CallMsg.GasFeeCap }
-func (m callMsg) GasTipCap() *big.Int          { return m.CallMsg.GasTipCap }
-func (m callMsg) Gas() uint64                  { return m.CallMsg.Gas }
-func (m callMsg) Value() *big.Int              { return m.CallMsg.Value }
-func (m callMsg) Data() []byte                 { return m.CallMsg.Data }
-func (m callMsg) AccessList() types.AccessList { return m.CallMsg.AccessList }
-
-// filterBackend implements filters.Backend to support filtering for logs without
-// taking bloom-bits acceleration structures into account.
-type filterBackend struct {
-	db      ethdb.Database
-	bc      *core.BlockChain
-	backend *SimulatedBackend
-}
-
-func (fb *filterBackend) ChainDb() ethdb.Database { return fb.db }
-
-func (fb *filterBackend) EventMux() *event.TypeMux { panic("not supported") }
-
-func (fb *filterBackend) HeaderByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Header, error) {
-	switch number {
-	case rpc.PendingBlockNumber:
-		if block := fb.backend.pendingBlock; block != nil {
-			return block.Header(), nil
-		}
-		return nil, nil
-	case rpc.LatestBlockNumber:
-		return fb.bc.CurrentHeader(), nil
-	case rpc.FinalizedBlockNumber:
-		return fb.bc.CurrentFinalBlock(), nil
-	case rpc.SafeBlockNumber:
-		return fb.bc.CurrentSafeBlock(), nil
-	default:
-		return fb.bc.GetHeaderByNumber(uint64(number.Int64())), nil
-	}
-}
-
-func (fb *filterBackend) HeaderByHash(ctx context.Context, hash common.Hash) (*types.Header, error) {
-	return fb.bc.GetHeaderByHash(hash), nil
-}
-
-func (fb *filterBackend) GetBody(ctx context.Context, hash common.Hash, number rpc.BlockNumber) (*types.Body, error) {
-	if body := fb.bc.GetBody(hash); body != nil {
-		return body, nil
-	}
-	return nil, errors.New("block body not found")
-}
-
-func (fb *filterBackend) PendingBlockAndReceipts() (*types.Block, types.Receipts) {
-	return fb.backend.pendingBlock, fb.backend.pendingReceipts
-}
-
-func (fb *filterBackend) GetReceipts(ctx context.Context, hash common.Hash) (types.Receipts, error) {
-	number := rawdb.ReadHeaderNumber(fb.db, hash)
-	if number == nil {
-		return nil, nil
-	}
-	return rawdb.ReadReceipts(fb.db, hash, *number, fb.bc.Config()), nil
-}
-
-func (fb *filterBackend) GetLogs(ctx context.Context, hash common.Hash, number uint64) ([][]*types.Log, error) {
-	logs := rawdb.ReadLogs(fb.db, hash, number, fb.bc.Config())
-	return logs, nil
-}
-
-func (fb *filterBackend) SubscribeNewTxsEvent(ch chan<- core.NewTxsEvent) event.Subscription {
-	return nullSubscription()
-}
-
-func (fb *filterBackend) SubscribeChainEvent(ch chan<- core.ChainEvent) event.Subscription {
-	return fb.bc.SubscribeChainEvent(ch)
-}
-
-func (fb *filterBackend) SubscribeRemovedLogsEvent(ch chan<- core.RemovedLogsEvent) event.Subscription {
-	return fb.bc.SubscribeRemovedLogsEvent(ch)
-}
-
-func (fb *filterBackend) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscription {
-	return fb.bc.SubscribeLogsEvent(ch)
-}
-
-func (fb *filterBackend) SubscribePendingLogsEvent(ch chan<- []*types.Log) event.Subscription {
-	return nullSubscription()
-}
-
-func (fb *filterBackend) BloomStatus() (uint64, uint64) { return 4096, 0 }
-
-func (fb *filterBackend) ServiceFilter(ctx context.Context, ms *bloombits.MatcherSession) {
-	panic("not supported")
-}
-
-func (fb *filterBackend) ChainConfig() *params.ChainConfig {
-	panic("not supported")
-}
-
-func (fb *filterBackend) CurrentHeader() *types.Header {
-	panic("not supported")
-}
-
-func nullSubscription() event.Subscription {
-	return event.NewSubscription(func(quit <-chan struct{}) error {
-		<-quit
-		return nil
-	})
-}

accounts/abi/bind/base.go

@@ -34,6 +34,11 @@ import (
 
 const basefeeWiggleMultiplier = 2
 
+var (
+	errNoEventSignature       = errors.New("no event signature")
+	errEventSignatureMismatch = errors.New("event signature mismatch")
+)
+
 // SignerFn is a signer function callback when a contract requires a method to
 // sign the transaction before submission.
 type SignerFn func(common.Address, *types.Transaction) (*types.Transaction, error)
@@ -43,6 +48,7 @@ type CallOpts struct {
 	Pending     bool            // Whether to operate on the pending state or the last known one
 	From        common.Address  // Optional the sender address, otherwise the first account is used
 	BlockNumber *big.Int        // Optional the block number on which the call should be performed
+	BlockHash   common.Hash     // Optional the block hash on which the call should be performed
 	Context     context.Context // Network context to support cancellation and timeouts (nil = no timeout)
 }
 
@@ -184,6 +190,23 @@ func (c *BoundContract) Call(opts *CallOpts, results *[]interface{}, method stri
 				return ErrNoCode
 			}
 		}
+	} else if opts.BlockHash != (common.Hash{}) {
+		bh, ok := c.caller.(BlockHashContractCaller)
+		if !ok {
+			return ErrNoBlockHashState
+		}
+		output, err = bh.CallContractAtHash(ctx, msg, opts.BlockHash)
+		if err != nil {
+			return err
+		}
+		if len(output) == 0 {
+			// Make sure we have a contract to operate on, and bail out otherwise.
+			if code, err = bh.CodeAtHash(ctx, c.address, opts.BlockHash); err != nil {
+				return err
+			} else if len(code) == 0 {
+				return ErrNoCode
+			}
+		}
 	} else {
 		output, err = c.caller.CallContract(ctx, msg, opts.BlockNumber)
 		if err != nil {
@@ -215,7 +238,7 @@ func (c *BoundContract) Transact(opts *TransactOpts, method string, params ...in
 	if err != nil {
 		return nil, err
 	}
-	// todo(rjl493456442) check the method is payable or not,
+	// todo(rjl493456442) check whether the method is payable or not,
 	// reject invalid transaction at the first place
 	return c.transact(opts, &c.address, input)
 }
@@ -223,7 +246,7 @@ func (c *BoundContract) Transact(opts *TransactOpts, method string, params ...in
 // RawTransact initiates a transaction with the given raw calldata as the input.
 // It's usually used to initiate transactions for invoking **Fallback** function.
 func (c *BoundContract) RawTransact(opts *TransactOpts, calldata []byte) (*types.Transaction, error) {
-	// todo(rjl493456442) check the method is payable or not,
+	// todo(rjl493456442) check whether the method is payable or not,
 	// reject invalid transaction at the first place
 	return c.transact(opts, &c.address, calldata)
 }
@@ -438,7 +461,7 @@ func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]int
 	if err != nil {
 		return nil, nil, err
 	}
-	sub, err := event.NewSubscription(func(quit <-chan struct{}) error {
+	sub := event.NewSubscription(func(quit <-chan struct{}) error {
 		for _, log := range buff {
 			select {
 			case logs <- log:
@@ -447,11 +470,8 @@ func (c *BoundContract) FilterLogs(opts *FilterOpts, name string, query ...[]int
 			}
 		}
 		return nil
-	}), nil
+	})
 
-	if err != nil {
-		return nil, nil, err
-	}
 	return logs, sub, nil
 }
 
@@ -488,8 +508,12 @@ func (c *BoundContract) WatchLogs(opts *WatchOpts, name string, query ...[]inter
 
 // UnpackLog unpacks a retrieved log into the provided output structure.
 func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log) error {
+	// Anonymous events are not supported.
+	if len(log.Topics) == 0 {
+		return errNoEventSignature
+	}
 	if log.Topics[0] != c.abi.Events[event].ID {
-		return fmt.Errorf("event signature mismatch")
+		return errEventSignatureMismatch
 	}
 	if len(log.Data) > 0 {
 		if err := c.abi.UnpackIntoInterface(out, event, log.Data); err != nil {
@@ -507,8 +531,12 @@ func (c *BoundContract) UnpackLog(out interface{}, event string, log types.Log)
 
 // UnpackLogIntoMap unpacks a retrieved log into the provided map.
 func (c *BoundContract) UnpackLogIntoMap(out map[string]interface{}, event string, log types.Log) error {
+	// Anonymous events are not supported.
+	if len(log.Topics) == 0 {
+		return errNoEventSignature
+	}
 	if log.Topics[0] != c.abi.Events[event].ID {
-		return fmt.Errorf("event signature mismatch")
+		return errEventSignatureMismatch
 	}
 	if len(log.Data) > 0 {
 		if err := c.abi.UnpackIntoMap(out, event, log.Data); err != nil {

accounts/abi/bind/base_test.go

@@ -114,7 +114,28 @@ func (mc *mockPendingCaller) PendingCallContract(ctx context.Context, call ether
 	return mc.pendingCallContractBytes, mc.pendingCallContractErr
 }
 
+type mockBlockHashCaller struct {
+	*mockCaller
+	codeAtHashBytes          []byte
+	codeAtHashErr            error
+	codeAtHashCalled         bool
+	callContractAtHashCalled bool
+	callContractAtHashBytes  []byte
+	callContractAtHashErr    error
+}
+
+func (mc *mockBlockHashCaller) CodeAtHash(ctx context.Context, contract common.Address, hash common.Hash) ([]byte, error) {
+	mc.codeAtHashCalled = true
+	return mc.codeAtHashBytes, mc.codeAtHashErr
+}
+
+func (mc *mockBlockHashCaller) CallContractAtHash(ctx context.Context, call ethereum.CallMsg, hash common.Hash) ([]byte, error) {
+	mc.callContractAtHashCalled = true
+	return mc.callContractAtHashBytes, mc.callContractAtHashErr
+}
+
 func TestPassingBlockNumber(t *testing.T) {
+	t.Parallel()
 	mc := &mockPendingCaller{
 		mockCaller: &mockCaller{
 			codeAtBytes: []byte{1, 2, 3},
@@ -166,6 +187,7 @@ func TestPassingBlockNumber(t *testing.T) {
 const hexData = "0x000000000000000000000000376c47978271565f56deb45495afa69e59c16ab200000000000000000000000000000000000000000000000000000000000000010000000000000000000000000000000000000000000000000000000000000060000000000000000000000000000000000000000000000000000000000000000158"
 
 func TestUnpackIndexedStringTyLogIntoMap(t *testing.T) {
+	t.Parallel()
 	hash := crypto.Keccak256Hash([]byte("testName"))
 	topics := []common.Hash{
 		crypto.Keccak256Hash([]byte("received(string,address,uint256,bytes)")),
@@ -186,7 +208,26 @@ func TestUnpackIndexedStringTyLogIntoMap(t *testing.T) {
 	unpackAndCheck(t, bc, expectedReceivedMap, mockLog)
 }
 
+func TestUnpackAnonymousLogIntoMap(t *testing.T) {
+	t.Parallel()
+	mockLog := newMockLog(nil, common.HexToHash("0x0"))
+
+	abiString := `[{"anonymous":false,"inputs":[{"indexed":false,"name":"amount","type":"uint256"}],"name":"received","type":"event"}]`
+	parsedAbi, _ := abi.JSON(strings.NewReader(abiString))
+	bc := bind.NewBoundContract(common.HexToAddress("0x0"), parsedAbi, nil, nil, nil)
+
+	var received map[string]interface{}
+	err := bc.UnpackLogIntoMap(received, "received", mockLog)
+	if err == nil {
+		t.Error("unpacking anonymous event is not supported")
+	}
+	if err.Error() != "no event signature" {
+		t.Errorf("expected error 'no event signature', got '%s'", err)
+	}
+}
+
 func TestUnpackIndexedSliceTyLogIntoMap(t *testing.T) {
+	t.Parallel()
 	sliceBytes, err := rlp.EncodeToBytes([]string{"name1", "name2", "name3", "name4"})
 	if err != nil {
 		t.Fatal(err)
@@ -212,6 +253,7 @@ func TestUnpackIndexedSliceTyLogIntoMap(t *testing.T) {
 }
 
 func TestUnpackIndexedArrayTyLogIntoMap(t *testing.T) {
+	t.Parallel()
 	arrBytes, err := rlp.EncodeToBytes([2]common.Address{common.HexToAddress("0x0"), common.HexToAddress("0x376c47978271565f56DEB45495afa69E59c16Ab2")})
 	if err != nil {
 		t.Fatal(err)
@@ -237,6 +279,7 @@ func TestUnpackIndexedArrayTyLogIntoMap(t *testing.T) {
 }
 
 func TestUnpackIndexedFuncTyLogIntoMap(t *testing.T) {
+	t.Parallel()
 	mockAddress := common.HexToAddress("0x376c47978271565f56DEB45495afa69E59c16Ab2")
 	addrBytes := mockAddress.Bytes()
 	hash := crypto.Keccak256Hash([]byte("mockFunction(address,uint)"))
@@ -263,6 +306,7 @@ func TestUnpackIndexedFuncTyLogIntoMap(t *testing.T) {
 }
 
 func TestUnpackIndexedBytesTyLogIntoMap(t *testing.T) {
+	t.Parallel()
 	bytes := []byte{1, 2, 3, 4, 5}
 	hash := crypto.Keccak256Hash(bytes)
 	topics := []common.Hash{
@@ -285,6 +329,7 @@ func TestUnpackIndexedBytesTyLogIntoMap(t *testing.T) {
 }
 
 func TestTransactGasFee(t *testing.T) {
+	t.Parallel()
 	assert := assert.New(t)
 
 	// GasTipCap and GasFeeCap
@@ -360,6 +405,7 @@ func newMockLog(topics []common.Hash, txHash common.Hash) types.Log {
 }
 
 func TestCall(t *testing.T) {
+	t.Parallel()
 	var method, methodWithArg = "something", "somethingArrrrg"
 	tests := []struct {
 		name, method string
@@ -383,6 +429,15 @@ func TestCall(t *testing.T) {
 			Pending: true,
 		},
 		method: method,
+	}, {
+		name: "ok hash",
+		mc: &mockBlockHashCaller{
+			codeAtHashBytes: []byte{0},
+		},
+		opts: &bind.CallOpts{
+			BlockHash: common.Hash{0xaa},
+		},
+		method: method,
 	}, {
 		name:    "pack error, no method",
 		mc:      new(mockCaller),
@@ -396,6 +451,14 @@ func TestCall(t *testing.T) {
 		},
 		method:       method,
 		wantErrExact: bind.ErrNoPendingState,
+	}, {
+		name: "interface error, blockHash but not a BlockHashContractCaller",
+		mc:   new(mockCaller),
+		opts: &bind.CallOpts{
+			BlockHash: common.Hash{0xaa},
+		},
+		method:       method,
+		wantErrExact: bind.ErrNoBlockHashState,
 	}, {
 		name: "pending call canceled",
 		mc: &mockPendingCaller{
@@ -443,6 +506,34 @@ func TestCall(t *testing.T) {
 		mc:           new(mockCaller),
 		method:       method,
 		wantErrExact: bind.ErrNoCode,
+	}, {
+		name: "call contract at hash error",
+		mc: &mockBlockHashCaller{
+			callContractAtHashErr: context.DeadlineExceeded,
+		},
+		opts: &bind.CallOpts{
+			BlockHash: common.Hash{0xaa},
+		},
+		method:       method,
+		wantErrExact: context.DeadlineExceeded,
+	}, {
+		name: "code at error",
+		mc: &mockBlockHashCaller{
+			codeAtHashErr: errors.New(""),
+		},
+		opts: &bind.CallOpts{
+			BlockHash: common.Hash{0xaa},
+		},
+		method:  method,
+		wantErr: true,
+	}, {
+		name: "no code at hash",
+		mc:   new(mockBlockHashCaller),
+		opts: &bind.CallOpts{
+			BlockHash: common.Hash{0xaa},
+		},
+		method:       method,
+		wantErrExact: bind.ErrNoCode,
 	}, {
 		name: "unpack error missing arg",
 		mc: &mockCaller{
@@ -490,6 +581,7 @@ func TestCall(t *testing.T) {
 
 // TestCrashers contains some strings which previously caused the abi codec to crash.
 func TestCrashers(t *testing.T) {
+	t.Parallel()
 	abi.JSON(strings.NewReader(`[{"inputs":[{"type":"tuple[]","components":[{"type":"bool","name":"_1"}]}]}]`))
 	abi.JSON(strings.NewReader(`[{"inputs":[{"type":"tuple[]","components":[{"type":"bool","name":"&"}]}]}]`))
 	abi.JSON(strings.NewReader(`[{"inputs":[{"type":"tuple[]","components":[{"type":"bool","name":"----"}]}]}]`))

accounts/abi/bind/bind.go

@@ -79,7 +79,7 @@ func isKeyWord(arg string) bool {
 
 // Bind generates a Go wrapper around a contract ABI. This wrapper isn't meant
 // to be used as is in client code, but rather as an intermediate struct which
-// enforces compile time type safety and naming convention opposed to having to
+// enforces compile time type safety and naming convention as opposed to having to
 // manually maintain hard coded strings that break on runtime.
 func Bind(types []string, abis []string, bytecodes []string, fsigs []map[string]string, pkg string, lang Lang, libs map[string]string, aliases map[string]string) (string, error) {
 	var (
@@ -133,12 +133,19 @@ func Bind(types []string, abis []string, bytecodes []string, fsigs []map[string]
 			// Normalize the method for capital cases and non-anonymous inputs/outputs
 			normalized := original
 			normalizedName := methodNormalizer[lang](alias(aliases, original.Name))
-
 			// Ensure there is no duplicated identifier
 			var identifiers = callIdentifiers
 			if !original.IsConstant() {
 				identifiers = transactIdentifiers
 			}
+			// Name shouldn't start with a digit. It will make the generated code invalid.
+			if len(normalizedName) > 0 && unicode.IsDigit(rune(normalizedName[0])) {
+				normalizedName = fmt.Sprintf("M%s", normalizedName)
+				normalizedName = abi.ResolveNameConflict(normalizedName, func(name string) bool {
+					_, ok := identifiers[name]
+					return ok
+				})
+			}
 			if identifiers[normalizedName] {
 				return "", fmt.Errorf("duplicated identifier \"%s\"(normalized \"%s\"), use --alias for renaming", original.Name, normalizedName)
 			}
@@ -182,6 +189,14 @@ func Bind(types []string, abis []string, bytecodes []string, fsigs []map[string]
 
 			// Ensure there is no duplicated identifier
 			normalizedName := methodNormalizer[lang](alias(aliases, original.Name))
+			// Name shouldn't start with a digit. It will make the generated code invalid.
+			if len(normalizedName) > 0 && unicode.IsDigit(rune(normalizedName[0])) {
+				normalizedName = fmt.Sprintf("E%s", normalizedName)
+				normalizedName = abi.ResolveNameConflict(normalizedName, func(name string) bool {
+					_, ok := eventIdentifiers[name]
+					return ok
+				})
+			}
 			if eventIdentifiers[normalizedName] {
 				return "", fmt.Errorf("duplicated identifier \"%s\"(normalized \"%s\"), use --alias for renaming", original.Name, normalizedName)
 			}
@@ -348,7 +363,7 @@ func bindTopicTypeGo(kind abi.Type, structs map[string]*tmplStruct) string {
 	// parameters that are not value types i.e. arrays and structs are not
 	// stored directly but instead a keccak256-hash of an encoding is stored.
 	//
-	// We only convert stringS and bytes to hash, still need to deal with
+	// We only convert strings and bytes to hash, still need to deal with
 	// array(both fixed-size and dynamic-size) and struct.
 	if bound == "string" || bound == "[]byte" {
 		bound = "common.Hash"

accounts/abi/bind/bind_test.go

@@ -289,7 +289,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -297,7 +297,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy an interaction tester contract and call a transaction on it
@@ -305,6 +305,7 @@ var bindTests = []struct {
 			if err != nil {
 				t.Fatalf("Failed to deploy interactor contract: %v", err)
 			}
+			sim.Commit()
 			if _, err := interactor.Transact(auth, "Transact string"); err != nil {
 				t.Fatalf("Failed to transact with interactor contract: %v", err)
 			}
@@ -344,7 +345,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -352,7 +353,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a tuple tester contract and execute a structured call on it
@@ -390,7 +391,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -398,7 +399,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a tuple tester contract and execute a structured call on it
@@ -448,7 +449,7 @@ var bindTests = []struct {
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 			"github.com/ethereum/go-ethereum/common"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -456,7 +457,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a slice tester contract and execute a n array call on it
@@ -496,7 +497,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -504,7 +505,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a default method invoker contract and execute its default method
@@ -512,6 +513,7 @@ var bindTests = []struct {
 			if err != nil {
 				t.Fatalf("Failed to deploy defaulter contract: %v", err)
 			}
+			sim.Commit()
 			if _, err := (&DefaulterRaw{defaulter}).Transfer(auth); err != nil {
 				t.Fatalf("Failed to invoke default method: %v", err)
 			}
@@ -562,7 +564,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -570,7 +572,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 		
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 		
 			// Deploy a structs method invoker contract and execute its default method
@@ -608,12 +610,12 @@ var bindTests = []struct {
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 			"github.com/ethereum/go-ethereum/common"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 		`,
 		`
 			// Create a simulator and wrap a non-deployed contract
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{}, uint64(10000000000))
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{}, uint64(10000000000))
 			defer sim.Close()
 
 			nonexistent, err := NewNonExistent(common.Address{}, sim)
@@ -647,12 +649,12 @@ var bindTests = []struct {
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 			"github.com/ethereum/go-ethereum/common"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 		`,
 		`
 			// Create a simulator and wrap a non-deployed contract
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{}, uint64(10000000000))
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{}, uint64(10000000000))
 			defer sim.Close()
 
 			nonexistent, err := NewNonExistentStruct(common.Address{}, sim)
@@ -694,7 +696,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -702,7 +704,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a funky gas pattern contract
@@ -744,7 +746,7 @@ var bindTests = []struct {
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 			"github.com/ethereum/go-ethereum/common"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -752,7 +754,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a sender tester contract and execute a structured call on it
@@ -819,7 +821,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -827,7 +829,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a underscorer tester contract and execute a structured call on it
@@ -913,7 +915,7 @@ var bindTests = []struct {
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 			"github.com/ethereum/go-ethereum/common"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -921,7 +923,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy an eventer contract
@@ -1103,7 +1105,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -1111,7 +1113,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			//deploy the test contract
@@ -1238,7 +1240,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 
@@ -1246,7 +1248,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			_, _, contract, err := DeployTuple(auth, sim)
@@ -1380,7 +1382,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -1388,7 +1390,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			//deploy the test contract
@@ -1446,14 +1448,14 @@ var bindTests = []struct {
 
 		"github.com/ethereum/go-ethereum/accounts/abi/bind"
 		"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-		"github.com/ethereum/go-ethereum/core"
+		"github.com/ethereum/go-ethereum/core/types"
 		"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
 		// Initialize test accounts
 		key, _ := crypto.GenerateKey()
 		auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-		sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+		sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 		defer sim.Close()
 
 		// deploy the test contract
@@ -1535,7 +1537,7 @@ var bindTests = []struct {
 		"github.com/ethereum/go-ethereum/accounts/abi/bind"
 		"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 		"github.com/ethereum/go-ethereum/crypto"
-		"github.com/ethereum/go-ethereum/core"
+		"github.com/ethereum/go-ethereum/core/types"
 		`,
 		`
 		// Initialize test accounts
@@ -1543,7 +1545,7 @@ var bindTests = []struct {
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 
 		// Deploy registrar contract
-		sim := backends.NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+		sim := backends.NewSimulatedBackend(types.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 		defer sim.Close()
 
 		transactOpts, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
@@ -1598,14 +1600,14 @@ var bindTests = []struct {
 		"github.com/ethereum/go-ethereum/accounts/abi/bind"
 		"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 		"github.com/ethereum/go-ethereum/crypto"
-		"github.com/ethereum/go-ethereum/core"
+		"github.com/ethereum/go-ethereum/core/types"
         `,
 		`
 		key, _ := crypto.GenerateKey()
 		addr := crypto.PubkeyToAddress(key.PublicKey)
 
 		// Deploy registrar contract
-		sim := backends.NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+		sim := backends.NewSimulatedBackend(types.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 		defer sim.Close()
 
 		transactOpts, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
@@ -1659,7 +1661,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 		`,
 		`
@@ -1667,7 +1669,7 @@ var bindTests = []struct {
 			key, _ := crypto.GenerateKey()
 			auth, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
 
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{auth.From: {Balance: big.NewInt(10000000000000000)}}, 10000000)
 			defer sim.Close()
 
 			// Deploy a tester contract and execute a structured call on it
@@ -1677,7 +1679,7 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 
-			// This test the existence of the free retreiver call for view and pure functions
+			// This test the existence of the free retriever call for view and pure functions
 			if num, err := pav.PureFunc(nil); err != nil {
 				t.Fatalf("Failed to call anonymous field retriever: %v", err)
 			} else if num.Cmp(big.NewInt(42)) != 0 {
@@ -1720,14 +1722,14 @@ var bindTests = []struct {
 	
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 	   `,
 		`
 			key, _ := crypto.GenerateKey()
 			addr := crypto.PubkeyToAddress(key.PublicKey)
 	
-			sim := backends.NewSimulatedBackend(core.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 1000000)
+			sim := backends.NewSimulatedBackend(types.GenesisAlloc{addr: {Balance: big.NewInt(10000000000000000)}}, 1000000)
 			defer sim.Close()
 	
 			opts, _ := bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
@@ -1808,7 +1810,7 @@ var bindTests = []struct {
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 			"github.com/ethereum/go-ethereum/eth/ethconfig"
 	   `,
@@ -1816,7 +1818,7 @@ var bindTests = []struct {
 			var (
 				key, _  = crypto.GenerateKey()
 				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+				sim     = backends.NewSimulatedBackend(types.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
 			)
 			defer sim.Close()
 
@@ -1874,11 +1876,12 @@ var bindTests = []struct {
 		[]string{"0x6080604052348015600f57600080fd5b5060998061001e6000396000f3fe6080604052348015600f57600080fd5b506004361060285760003560e01c8063726c638214602d575b600080fd5b60336035565b005b60405163024876cd60e61b815260016004820152600260248201526003604482015260640160405180910390fdfea264697066735822122093f786a1bc60216540cd999fbb4a6109e0fef20abcff6e9107fb2817ca968f3c64736f6c63430008070033"},
 		[]string{`[{"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError","type":"error"},{"inputs":[{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError1","type":"error"},{"inputs":[{"internalType":"uint256","name":"","type":"uint256"},{"internalType":"uint256","name":"","type":"uint256"}],"name":"MyError2","type":"error"},{"inputs":[{"internalType":"uint256","name":"a","type":"uint256"},{"internalType":"uint256","name":"b","type":"uint256"},{"internalType":"uint256","name":"c","type":"uint256"}],"name":"MyError3","type":"error"},{"inputs":[],"name":"Error","outputs":[],"stateMutability":"pure","type":"function"}]`},
 		`
+			"context"
 			"math/big"
 	
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 			"github.com/ethereum/go-ethereum/eth/ethconfig"
 	   `,
@@ -1886,7 +1889,7 @@ var bindTests = []struct {
 			var (
 				key, _  = crypto.GenerateKey()
 				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+				sim     = backends.NewSimulatedBackend(types.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
 			)
 			defer sim.Close()
 	
@@ -1895,7 +1898,7 @@ var bindTests = []struct {
 				t.Fatal(err)
 			}
 			sim.Commit()
-			_, err = bind.WaitDeployed(nil, sim, tx)
+			_, err = bind.WaitDeployed(context.Background(), sim, tx)
 			if err != nil {
 				t.Error(err)
 			}
@@ -1926,11 +1929,12 @@ var bindTests = []struct {
 		bytecode: []string{`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`},
 		abi:      []string{`[{"inputs":[{"components":[{"internalType":"uint256","name":"field","type":"uint256"}],"internalType":"struct ConstructorWithStructParam.StructType","name":"st","type":"tuple"}],"stateMutability":"nonpayable","type":"constructor"}]`},
 		imports: `
+			"context"
 			"math/big"
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 			"github.com/ethereum/go-ethereum/eth/ethconfig"
 		`,
@@ -1938,7 +1942,7 @@ var bindTests = []struct {
 			var (
 				key, _  = crypto.GenerateKey()
 				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+				sim     = backends.NewSimulatedBackend(types.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
 			)
 			defer sim.Close()
 
@@ -1948,7 +1952,7 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 			
-			if _, err = bind.WaitDeployed(nil, sim, tx); err != nil {
+			if _, err = bind.WaitDeployed(context.Background(), sim, tx); err != nil {
 				t.Logf("Deployment tx: %+v", tx)
 				t.Errorf("bind.WaitDeployed(nil, %T, <deployment tx>) got err %v; want nil err", sim, err)
 			}
@@ -1974,11 +1978,12 @@ var bindTests = []struct {
 		bytecode: []string{"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"},
 		abi:      []string{`[ { "anonymous": false, "inputs": [ { "indexed": false, "internalType": "int256", "name": "msg", "type": "int256" }, { "indexed": false, "internalType": "int256", "name": "_msg", "type": "int256" } ], "name": "log", "type": "event" }, { "inputs": [ { "components": [ { "internalType": "bytes", "name": "data", "type": "bytes" }, { "internalType": "bytes", "name": "_data", "type": "bytes" } ], "internalType": "struct oracle.request", "name": "req", "type": "tuple" } ], "name": "addRequest", "outputs": [], "stateMutability": "pure", "type": "function" }, { "inputs": [], "name": "getRequest", "outputs": [ { "components": [ { "internalType": "bytes", "name": "data", "type": "bytes" }, { "internalType": "bytes", "name": "_data", "type": "bytes" } ], "internalType": "struct oracle.request", "name": "", "type": "tuple" } ], "stateMutability": "pure", "type": "function" } ]`},
 		imports: `
+			"context"
 			"math/big"
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 			"github.com/ethereum/go-ethereum/eth/ethconfig"
 		`,
@@ -1986,7 +1991,7 @@ var bindTests = []struct {
 			var (
 				key, _  = crypto.GenerateKey()
 				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+				sim     = backends.NewSimulatedBackend(types.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
 			)
 			defer sim.Close()
 
@@ -1996,7 +2001,7 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 			
-			if _, err = bind.WaitDeployed(nil, sim, tx); err != nil {
+			if _, err = bind.WaitDeployed(context.Background(), sim, tx); err != nil {
 				t.Logf("Deployment tx: %+v", tx)
 				t.Errorf("bind.WaitDeployed(nil, %T, <deployment tx>) got err %v; want nil err", sim, err)
 			}
@@ -2014,11 +2019,12 @@ var bindTests = []struct {
 		bytecode: []string{"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"},
 		abi:      []string{`[{"inputs":[{"internalType":"uint256","name":"range","type":"uint256"}],"name":"functionWithKeywordParameter","outputs":[],"stateMutability":"pure","type":"function"}]`},
 		imports: `
+			"context"
 			"math/big"
 
 			"github.com/ethereum/go-ethereum/accounts/abi/bind"
 			"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
-			"github.com/ethereum/go-ethereum/core"
+			"github.com/ethereum/go-ethereum/core/types"
 			"github.com/ethereum/go-ethereum/crypto"
 			"github.com/ethereum/go-ethereum/eth/ethconfig"
 		`,
@@ -2026,7 +2032,7 @@ var bindTests = []struct {
 			var (
 				key, _  = crypto.GenerateKey()
 				user, _ = bind.NewKeyedTransactorWithChainID(key, big.NewInt(1337))
-				sim     = backends.NewSimulatedBackend(core.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
+				sim     = backends.NewSimulatedBackend(types.GenesisAlloc{user.From: {Balance: big.NewInt(1000000000000000000)}}, ethconfig.Defaults.Miner.GasCeil)
 			)
 			_, tx, _, err := DeployRangeKeyword(user, sim)
 			if err != nil {
@@ -2034,16 +2040,40 @@ var bindTests = []struct {
 			}
 			sim.Commit()
 
-			if _, err = bind.WaitDeployed(nil, sim, tx); err != nil {
+			if _, err = bind.WaitDeployed(context.Background(), sim, tx); err != nil {
 				t.Errorf("error deploying the contract: %v", err)
 			}
 		`,
+	}, {
+		name: "NumericMethodName",
+		contract: `
+		// SPDX-License-Identifier: GPL-3.0
+		pragma solidity >=0.4.22 <0.9.0;
+
+		contract NumericMethodName {
+			event _1TestEvent(address _param);
+			function _1test() public pure {}
+			function __1test() public pure {}
+			function __2test() public pure {}
+		}
+		`,
+		bytecode: []string{"0x6080604052348015600f57600080fd5b5060958061001e6000396000f3fe6080604052348015600f57600080fd5b5060043610603c5760003560e01c80639d993132146041578063d02767c7146049578063ffa02795146051575b600080fd5b60476059565b005b604f605b565b005b6057605d565b005b565b565b56fea26469706673582212200382ca602dff96a7e2ba54657985e2b4ac423a56abe4a1f0667bc635c4d4371f64736f6c63430008110033"},
+		abi:      []string{`[{"anonymous":false,"inputs":[{"indexed":false,"internalType":"address","name":"_param","type":"address"}],"name":"_1TestEvent","type":"event"},{"inputs":[],"name":"_1test","outputs":[],"stateMutability":"pure","type":"function"},{"inputs":[],"name":"__1test","outputs":[],"stateMutability":"pure","type":"function"},{"inputs":[],"name":"__2test","outputs":[],"stateMutability":"pure","type":"function"}]`},
+		imports: `
+			"github.com/ethereum/go-ethereum/common"
+		`,
+		tester: `
+			if b, err := NewNumericMethodName(common.Address{}, nil); b == nil || err != nil {
+				t.Fatalf("combined binding (%v) nil or error (%v) not nil", b, nil)
+			}
+`,
 	},
 }
 
 // Tests that packages generated by the binder can be successfully compiled and
 // the requested tester run against it.
 func TestGolangBindings(t *testing.T) {
+	t.Parallel()
 	// Skip the test if no Go command can be found
 	gocmd := runtime.GOROOT() + "/bin/go"
 	if !common.FileExist(gocmd) {

accounts/abi/bind/source.go.tpl

@@ -0,0 +1,487 @@
+// Code generated - DO NOT EDIT.
+// This file is a generated binding and any manual changes will be lost.
+
+package {{.Package}}
+
+import (
+	"math/big"
+	"strings"
+	"errors"
+
+	ethereum "github.com/ethereum/go-ethereum"
+	"github.com/ethereum/go-ethereum/accounts/abi"
+	"github.com/ethereum/go-ethereum/accounts/abi/bind"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/event"
+)
+
+// Reference imports to suppress errors if they are not otherwise used.
+var (
+	_ = errors.New
+	_ = big.NewInt
+	_ = strings.NewReader
+	_ = ethereum.NotFound
+	_ = bind.Bind
+	_ = common.Big1
+	_ = types.BloomLookup
+	_ = event.NewSubscription
+	_ = abi.ConvertType
+)
+
+{{$structs := .Structs}}
+{{range $structs}}
+	// {{.Name}} is an auto generated low-level Go binding around an user-defined struct.
+	type {{.Name}} struct {
+	{{range $field := .Fields}}
+	{{$field.Name}} {{$field.Type}}{{end}}
+	}
+{{end}}
+
+{{range $contract := .Contracts}}
+	// {{.Type}}MetaData contains all meta data concerning the {{.Type}} contract.
+	var {{.Type}}MetaData = &bind.MetaData{
+		ABI: "{{.InputABI}}",
+		{{if $contract.FuncSigs -}}
+		Sigs: map[string]string{
+			{{range $strsig, $binsig := .FuncSigs}}"{{$binsig}}": "{{$strsig}}",
+			{{end}}
+		},
+		{{end -}}
+		{{if .InputBin -}}
+		Bin: "0x{{.InputBin}}",
+		{{end}}
+	}
+	// {{.Type}}ABI is the input ABI used to generate the binding from.
+	// Deprecated: Use {{.Type}}MetaData.ABI instead.
+	var {{.Type}}ABI = {{.Type}}MetaData.ABI
+
+	{{if $contract.FuncSigs}}
+		// Deprecated: Use {{.Type}}MetaData.Sigs instead.
+		// {{.Type}}FuncSigs maps the 4-byte function signature to its string representation.
+		var {{.Type}}FuncSigs = {{.Type}}MetaData.Sigs
+	{{end}}
+
+	{{if .InputBin}}
+		// {{.Type}}Bin is the compiled bytecode used for deploying new contracts.
+		// Deprecated: Use {{.Type}}MetaData.Bin instead.
+		var {{.Type}}Bin = {{.Type}}MetaData.Bin
+
+		// Deploy{{.Type}} deploys a new Ethereum contract, binding an instance of {{.Type}} to it.
+		func Deploy{{.Type}}(auth *bind.TransactOpts, backend bind.ContractBackend {{range .Constructor.Inputs}}, {{.Name}} {{bindtype .Type $structs}}{{end}}) (common.Address, *types.Transaction, *{{.Type}}, error) {
+		  parsed, err := {{.Type}}MetaData.GetAbi()
+		  if err != nil {
+		    return common.Address{}, nil, nil, err
+		  }
+		  if parsed == nil {
+			return common.Address{}, nil, nil, errors.New("GetABI returned nil")
+		  }
+		  {{range $pattern, $name := .Libraries}}
+			{{decapitalise $name}}Addr, _, _, _ := Deploy{{capitalise $name}}(auth, backend)
+			{{$contract.Type}}Bin = strings.ReplaceAll({{$contract.Type}}Bin, "__${{$pattern}}$__", {{decapitalise $name}}Addr.String()[2:])
+		  {{end}}
+		  address, tx, contract, err := bind.DeployContract(auth, *parsed, common.FromHex({{.Type}}Bin), backend {{range .Constructor.Inputs}}, {{.Name}}{{end}})
+		  if err != nil {
+		    return common.Address{}, nil, nil, err
+		  }
+		  return address, tx, &{{.Type}}{ {{.Type}}Caller: {{.Type}}Caller{contract: contract}, {{.Type}}Transactor: {{.Type}}Transactor{contract: contract}, {{.Type}}Filterer: {{.Type}}Filterer{contract: contract} }, nil
+		}
+	{{end}}
+
+	// {{.Type}} is an auto generated Go binding around an Ethereum contract.
+	type {{.Type}} struct {
+	  {{.Type}}Caller     // Read-only binding to the contract
+	  {{.Type}}Transactor // Write-only binding to the contract
+	  {{.Type}}Filterer   // Log filterer for contract events
+	}
+
+	// {{.Type}}Caller is an auto generated read-only Go binding around an Ethereum contract.
+	type {{.Type}}Caller struct {
+	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
+	}
+
+	// {{.Type}}Transactor is an auto generated write-only Go binding around an Ethereum contract.
+	type {{.Type}}Transactor struct {
+	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
+	}
+
+	// {{.Type}}Filterer is an auto generated log filtering Go binding around an Ethereum contract events.
+	type {{.Type}}Filterer struct {
+	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
+	}
+
+	// {{.Type}}Session is an auto generated Go binding around an Ethereum contract,
+	// with pre-set call and transact options.
+	type {{.Type}}Session struct {
+	  Contract     *{{.Type}}        // Generic contract binding to set the session for
+	  CallOpts     bind.CallOpts     // Call options to use throughout this session
+	  TransactOpts bind.TransactOpts // Transaction auth options to use throughout this session
+	}
+
+	// {{.Type}}CallerSession is an auto generated read-only Go binding around an Ethereum contract,
+	// with pre-set call options.
+	type {{.Type}}CallerSession struct {
+	  Contract *{{.Type}}Caller // Generic contract caller binding to set the session for
+	  CallOpts bind.CallOpts    // Call options to use throughout this session
+	}
+
+	// {{.Type}}TransactorSession is an auto generated write-only Go binding around an Ethereum contract,
+	// with pre-set transact options.
+	type {{.Type}}TransactorSession struct {
+	  Contract     *{{.Type}}Transactor // Generic contract transactor binding to set the session for
+	  TransactOpts bind.TransactOpts    // Transaction auth options to use throughout this session
+	}
+
+	// {{.Type}}Raw is an auto generated low-level Go binding around an Ethereum contract.
+	type {{.Type}}Raw struct {
+	  Contract *{{.Type}} // Generic contract binding to access the raw methods on
+	}
+
+	// {{.Type}}CallerRaw is an auto generated low-level read-only Go binding around an Ethereum contract.
+	type {{.Type}}CallerRaw struct {
+		Contract *{{.Type}}Caller // Generic read-only contract binding to access the raw methods on
+	}
+
+	// {{.Type}}TransactorRaw is an auto generated low-level write-only Go binding around an Ethereum contract.
+	type {{.Type}}TransactorRaw struct {
+		Contract *{{.Type}}Transactor // Generic write-only contract binding to access the raw methods on
+	}
+
+	// New{{.Type}} creates a new instance of {{.Type}}, bound to a specific deployed contract.
+	func New{{.Type}}(address common.Address, backend bind.ContractBackend) (*{{.Type}}, error) {
+	  contract, err := bind{{.Type}}(address, backend, backend, backend)
+	  if err != nil {
+	    return nil, err
+	  }
+	  return &{{.Type}}{ {{.Type}}Caller: {{.Type}}Caller{contract: contract}, {{.Type}}Transactor: {{.Type}}Transactor{contract: contract}, {{.Type}}Filterer: {{.Type}}Filterer{contract: contract} }, nil
+	}
+
+	// New{{.Type}}Caller creates a new read-only instance of {{.Type}}, bound to a specific deployed contract.
+	func New{{.Type}}Caller(address common.Address, caller bind.ContractCaller) (*{{.Type}}Caller, error) {
+	  contract, err := bind{{.Type}}(address, caller, nil, nil)
+	  if err != nil {
+	    return nil, err
+	  }
+	  return &{{.Type}}Caller{contract: contract}, nil
+	}
+
+	// New{{.Type}}Transactor creates a new write-only instance of {{.Type}}, bound to a specific deployed contract.
+	func New{{.Type}}Transactor(address common.Address, transactor bind.ContractTransactor) (*{{.Type}}Transactor, error) {
+	  contract, err := bind{{.Type}}(address, nil, transactor, nil)
+	  if err != nil {
+	    return nil, err
+	  }
+	  return &{{.Type}}Transactor{contract: contract}, nil
+	}
+
+	// New{{.Type}}Filterer creates a new log filterer instance of {{.Type}}, bound to a specific deployed contract.
+ 	func New{{.Type}}Filterer(address common.Address, filterer bind.ContractFilterer) (*{{.Type}}Filterer, error) {
+ 	  contract, err := bind{{.Type}}(address, nil, nil, filterer)
+ 	  if err != nil {
+ 	    return nil, err
+ 	  }
+ 	  return &{{.Type}}Filterer{contract: contract}, nil
+ 	}
+
+	// bind{{.Type}} binds a generic wrapper to an already deployed contract.
+	func bind{{.Type}}(address common.Address, caller bind.ContractCaller, transactor bind.ContractTransactor, filterer bind.ContractFilterer) (*bind.BoundContract, error) {
+	  parsed, err := {{.Type}}MetaData.GetAbi()
+	  if err != nil {
+	    return nil, err
+	  }
+	  return bind.NewBoundContract(address, *parsed, caller, transactor, filterer), nil
+	}
+
+	// Call invokes the (constant) contract method with params as input values and
+	// sets the output to result. The result type might be a single field for simple
+	// returns, a slice of interfaces for anonymous returns and a struct for named
+	// returns.
+	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Call(opts *bind.CallOpts, result *[]interface{}, method string, params ...interface{}) error {
+		return _{{$contract.Type}}.Contract.{{$contract.Type}}Caller.contract.Call(opts, result, method, params...)
+	}
+
+	// Transfer initiates a plain transaction to move funds to the contract, calling
+	// its default method if one is available.
+	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Transfer(opts *bind.TransactOpts) (*types.Transaction, error) {
+		return _{{$contract.Type}}.Contract.{{$contract.Type}}Transactor.contract.Transfer(opts)
+	}
+
+	// Transact invokes the (paid) contract method with params as input values.
+	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Transact(opts *bind.TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
+		return _{{$contract.Type}}.Contract.{{$contract.Type}}Transactor.contract.Transact(opts, method, params...)
+	}
+
+	// Call invokes the (constant) contract method with params as input values and
+	// sets the output to result. The result type might be a single field for simple
+	// returns, a slice of interfaces for anonymous returns and a struct for named
+	// returns.
+	func (_{{$contract.Type}} *{{$contract.Type}}CallerRaw) Call(opts *bind.CallOpts, result *[]interface{}, method string, params ...interface{}) error {
+		return _{{$contract.Type}}.Contract.contract.Call(opts, result, method, params...)
+	}
+
+	// Transfer initiates a plain transaction to move funds to the contract, calling
+	// its default method if one is available.
+	func (_{{$contract.Type}} *{{$contract.Type}}TransactorRaw) Transfer(opts *bind.TransactOpts) (*types.Transaction, error) {
+		return _{{$contract.Type}}.Contract.contract.Transfer(opts)
+	}
+
+	// Transact invokes the (paid) contract method with params as input values.
+	func (_{{$contract.Type}} *{{$contract.Type}}TransactorRaw) Transact(opts *bind.TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
+		return _{{$contract.Type}}.Contract.contract.Transact(opts, method, params...)
+	}
+
+	{{range .Calls}}
+		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Caller) {{.Normalized.Name}}(opts *bind.CallOpts {{range .Normalized.Inputs}}, {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} },{{else}}{{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}}{{end}} error) {
+			var out []interface{}
+			err := _{{$contract.Type}}.contract.Call(opts, &out, "{{.Original.Name}}" {{range .Normalized.Inputs}}, {{.Name}}{{end}})
+			{{if .Structured}}
+			outstruct := new(struct{ {{range .Normalized.Outputs}} {{.Name}} {{bindtype .Type $structs}}; {{end}} })
+			if err != nil {
+				return *outstruct, err
+			}
+			{{range $i, $t := .Normalized.Outputs}}
+			outstruct.{{.Name}} = *abi.ConvertType(out[{{$i}}], new({{bindtype .Type $structs}})).(*{{bindtype .Type $structs}}){{end}}
+
+			return *outstruct, err
+			{{else}}
+			if err != nil {
+				return {{range $i, $_ := .Normalized.Outputs}}*new({{bindtype .Type $structs}}), {{end}} err
+			}
+			{{range $i, $t := .Normalized.Outputs}}
+			out{{$i}} := *abi.ConvertType(out[{{$i}}], new({{bindtype .Type $structs}})).(*{{bindtype .Type $structs}}){{end}}
+
+			return {{range $i, $t := .Normalized.Outputs}}out{{$i}}, {{end}} err
+			{{end}}
+		}
+
+		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Session) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} }, {{else}} {{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}} {{end}} error) {
+		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.CallOpts {{range .Normalized.Inputs}}, {{.Name}}{{end}})
+		}
+
+		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}CallerSession) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} }, {{else}} {{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}} {{end}} error) {
+		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.CallOpts {{range .Normalized.Inputs}}, {{.Name}}{{end}})
+		}
+	{{end}}
+
+	{{range .Transacts}}
+		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) {{.Normalized.Name}}(opts *bind.TransactOpts {{range .Normalized.Inputs}}, {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
+			return _{{$contract.Type}}.contract.Transact(opts, "{{.Original.Name}}" {{range .Normalized.Inputs}}, {{.Name}}{{end}})
+		}
+
+		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Session) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.TransactOpts {{range $i, $_ := .Normalized.Inputs}}, {{.Name}}{{end}})
+		}
+
+		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.TransactOpts {{range $i, $_ := .Normalized.Inputs}}, {{.Name}}{{end}})
+		}
+	{{end}}
+
+	{{if .Fallback}}
+		// Fallback is a paid mutator transaction binding the contract fallback function.
+		//
+		// Solidity: {{.Fallback.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) Fallback(opts *bind.TransactOpts, calldata []byte) (*types.Transaction, error) {
+			return _{{$contract.Type}}.contract.RawTransact(opts, calldata)
+		}
+
+		// Fallback is a paid mutator transaction binding the contract fallback function.
+		//
+		// Solidity: {{.Fallback.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Session) Fallback(calldata []byte) (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.Fallback(&_{{$contract.Type}}.TransactOpts, calldata)
+		}
+
+		// Fallback is a paid mutator transaction binding the contract fallback function.
+		//
+		// Solidity: {{.Fallback.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) Fallback(calldata []byte) (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.Fallback(&_{{$contract.Type}}.TransactOpts, calldata)
+		}
+	{{end}}
+
+	{{if .Receive}}
+		// Receive is a paid mutator transaction binding the contract receive function.
+		//
+		// Solidity: {{.Receive.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) Receive(opts *bind.TransactOpts) (*types.Transaction, error) {
+			return _{{$contract.Type}}.contract.RawTransact(opts, nil) // calldata is disallowed for receive function
+		}
+
+		// Receive is a paid mutator transaction binding the contract receive function.
+		//
+		// Solidity: {{.Receive.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Session) Receive() (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.Receive(&_{{$contract.Type}}.TransactOpts)
+		}
+
+		// Receive is a paid mutator transaction binding the contract receive function.
+		//
+		// Solidity: {{.Receive.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) Receive() (*types.Transaction, error) {
+		  return _{{$contract.Type}}.Contract.Receive(&_{{$contract.Type}}.TransactOpts)
+		}
+	{{end}}
+
+	{{range .Events}}
+		// {{$contract.Type}}{{.Normalized.Name}}Iterator is returned from Filter{{.Normalized.Name}} and is used to iterate over the raw logs and unpacked data for {{.Normalized.Name}} events raised by the {{$contract.Type}} contract.
+		type {{$contract.Type}}{{.Normalized.Name}}Iterator struct {
+			Event *{{$contract.Type}}{{.Normalized.Name}} // Event containing the contract specifics and raw log
+
+			contract *bind.BoundContract // Generic contract to use for unpacking event data
+			event    string              // Event name to use for unpacking event data
+
+			logs chan types.Log        // Log channel receiving the found contract events
+			sub  ethereum.Subscription // Subscription for errors, completion and termination
+			done bool                  // Whether the subscription completed delivering logs
+			fail error                 // Occurred error to stop iteration
+		}
+		// Next advances the iterator to the subsequent event, returning whether there
+		// are any more events found. In case of a retrieval or parsing error, false is
+		// returned and Error() can be queried for the exact failure.
+		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Next() bool {
+			// If the iterator failed, stop iterating
+			if (it.fail != nil) {
+				return false
+			}
+			// If the iterator completed, deliver directly whatever's available
+			if (it.done) {
+				select {
+				case log := <-it.logs:
+					it.Event = new({{$contract.Type}}{{.Normalized.Name}})
+					if err := it.contract.UnpackLog(it.Event, it.event, log); err != nil {
+						it.fail = err
+						return false
+					}
+					it.Event.Raw = log
+					return true
+
+				default:
+					return false
+				}
+			}
+			// Iterator still in progress, wait for either a data or an error event
+			select {
+			case log := <-it.logs:
+				it.Event = new({{$contract.Type}}{{.Normalized.Name}})
+				if err := it.contract.UnpackLog(it.Event, it.event, log); err != nil {
+					it.fail = err
+					return false
+				}
+				it.Event.Raw = log
+				return true
+
+			case err := <-it.sub.Err():
+				it.done = true
+				it.fail = err
+				return it.Next()
+			}
+		}
+		// Error returns any retrieval or parsing error occurred during filtering.
+		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Error() error {
+			return it.fail
+		}
+		// Close terminates the iteration process, releasing any pending underlying
+		// resources.
+		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Close() error {
+			it.sub.Unsubscribe()
+			return nil
+		}
+
+		// {{$contract.Type}}{{.Normalized.Name}} represents a {{.Normalized.Name}} event raised by the {{$contract.Type}} contract.
+		type {{$contract.Type}}{{.Normalized.Name}} struct { {{range .Normalized.Inputs}}
+			{{capitalise .Name}} {{if .Indexed}}{{bindtopictype .Type $structs}}{{else}}{{bindtype .Type $structs}}{{end}}; {{end}}
+			Raw types.Log // Blockchain specific contextual infos
+		}
+
+		// Filter{{.Normalized.Name}} is a free log retrieval operation binding the contract event 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+ 		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Filter{{.Normalized.Name}}(opts *bind.FilterOpts{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}} []{{bindtype .Type $structs}}{{end}}{{end}}) (*{{$contract.Type}}{{.Normalized.Name}}Iterator, error) {
+			{{range .Normalized.Inputs}}
+			{{if .Indexed}}var {{.Name}}Rule []interface{}
+			for _, {{.Name}}Item := range {{.Name}} {
+				{{.Name}}Rule = append({{.Name}}Rule, {{.Name}}Item)
+			}{{end}}{{end}}
+
+			logs, sub, err := _{{$contract.Type}}.contract.FilterLogs(opts, "{{.Original.Name}}"{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}}Rule{{end}}{{end}})
+			if err != nil {
+				return nil, err
+			}
+			return &{{$contract.Type}}{{.Normalized.Name}}Iterator{contract: _{{$contract.Type}}.contract, event: "{{.Original.Name}}", logs: logs, sub: sub}, nil
+ 		}
+
+		// Watch{{.Normalized.Name}} is a free log subscription operation binding the contract event 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Watch{{.Normalized.Name}}(opts *bind.WatchOpts, sink chan<- *{{$contract.Type}}{{.Normalized.Name}}{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}} []{{bindtype .Type $structs}}{{end}}{{end}}) (event.Subscription, error) {
+			{{range .Normalized.Inputs}}
+			{{if .Indexed}}var {{.Name}}Rule []interface{}
+			for _, {{.Name}}Item := range {{.Name}} {
+				{{.Name}}Rule = append({{.Name}}Rule, {{.Name}}Item)
+			}{{end}}{{end}}
+
+			logs, sub, err := _{{$contract.Type}}.contract.WatchLogs(opts, "{{.Original.Name}}"{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}}Rule{{end}}{{end}})
+			if err != nil {
+				return nil, err
+			}
+			return event.NewSubscription(func(quit <-chan struct{}) error {
+				defer sub.Unsubscribe()
+				for {
+					select {
+					case log := <-logs:
+						// New log arrived, parse the event and forward to the user
+						event := new({{$contract.Type}}{{.Normalized.Name}})
+						if err := _{{$contract.Type}}.contract.UnpackLog(event, "{{.Original.Name}}", log); err != nil {
+							return err
+						}
+						event.Raw = log
+
+						select {
+						case sink <- event:
+						case err := <-sub.Err():
+							return err
+						case <-quit:
+							return nil
+						}
+					case err := <-sub.Err():
+						return err
+					case <-quit:
+						return nil
+					}
+				}
+			}), nil
+		}
+
+		// Parse{{.Normalized.Name}} is a log parse operation binding the contract event 0x{{printf "%x" .Original.ID}}.
+		//
+		// Solidity: {{.Original.String}}
+		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Parse{{.Normalized.Name}}(log types.Log) (*{{$contract.Type}}{{.Normalized.Name}}, error) {
+			event := new({{$contract.Type}}{{.Normalized.Name}})
+			if err := _{{$contract.Type}}.contract.UnpackLog(event, "{{.Original.Name}}", log); err != nil {
+				return nil, err
+			}
+			event.Raw = log
+			return event, nil
+		}
+
+ 	{{end}}
+{{end}}

accounts/abi/bind/template.go

@@ -16,7 +16,11 @@
 
 package bind
 
-import "github.com/ethereum/go-ethereum/accounts/abi"
+import (
+	_ "embed"
+
+	"github.com/ethereum/go-ethereum/accounts/abi"
+)
 
 // tmplData is the data structure required to fill the binding template.
 type tmplData struct {
@@ -80,492 +84,6 @@ var tmplSource = map[Lang]string{
 
 // tmplSourceGo is the Go source template that the generated Go contract binding
 // is based on.
-const tmplSourceGo = `
-// Code generated - DO NOT EDIT.
-// This file is a generated binding and any manual changes will be lost.
-
-package {{.Package}}
-
-import (
-	"math/big"
-	"strings"
-	"errors"
-
-	ethereum "github.com/ethereum/go-ethereum"
-	"github.com/ethereum/go-ethereum/accounts/abi"
-	"github.com/ethereum/go-ethereum/accounts/abi/bind"
-	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core/types"
-	"github.com/ethereum/go-ethereum/event"
-)
-
-// Reference imports to suppress errors if they are not otherwise used.
-var (
-	_ = errors.New
-	_ = big.NewInt
-	_ = strings.NewReader
-	_ = ethereum.NotFound
-	_ = bind.Bind
-	_ = common.Big1
-	_ = types.BloomLookup
-	_ = event.NewSubscription
-	_ = abi.ConvertType
-)
-
-{{$structs := .Structs}}
-{{range $structs}}
-	// {{.Name}} is an auto generated low-level Go binding around an user-defined struct.
-	type {{.Name}} struct {
-	{{range $field := .Fields}}
-	{{$field.Name}} {{$field.Type}}{{end}}
-	}
-{{end}}
-
-{{range $contract := .Contracts}}
-	// {{.Type}}MetaData contains all meta data concerning the {{.Type}} contract.
-	var {{.Type}}MetaData = &bind.MetaData{
-		ABI: "{{.InputABI}}",
-		{{if $contract.FuncSigs -}}
-		Sigs: map[string]string{
-			{{range $strsig, $binsig := .FuncSigs}}"{{$binsig}}": "{{$strsig}}",
-			{{end}}
-		},
-		{{end -}}
-		{{if .InputBin -}}
-		Bin: "0x{{.InputBin}}",
-		{{end}}
-	}
-	// {{.Type}}ABI is the input ABI used to generate the binding from.
-	// Deprecated: Use {{.Type}}MetaData.ABI instead.
-	var {{.Type}}ABI = {{.Type}}MetaData.ABI
-
-	{{if $contract.FuncSigs}}
-		// Deprecated: Use {{.Type}}MetaData.Sigs instead.
-		// {{.Type}}FuncSigs maps the 4-byte function signature to its string representation.
-		var {{.Type}}FuncSigs = {{.Type}}MetaData.Sigs
-	{{end}}
-
-	{{if .InputBin}}
-		// {{.Type}}Bin is the compiled bytecode used for deploying new contracts.
-		// Deprecated: Use {{.Type}}MetaData.Bin instead.
-		var {{.Type}}Bin = {{.Type}}MetaData.Bin
-
-		// Deploy{{.Type}} deploys a new Ethereum contract, binding an instance of {{.Type}} to it.
-		func Deploy{{.Type}}(auth *bind.TransactOpts, backend bind.ContractBackend {{range .Constructor.Inputs}}, {{.Name}} {{bindtype .Type $structs}}{{end}}) (common.Address, *types.Transaction, *{{.Type}}, error) {
-		  parsed, err := {{.Type}}MetaData.GetAbi()
-		  if err != nil {
-		    return common.Address{}, nil, nil, err
-		  }
-		  if parsed == nil {
-			return common.Address{}, nil, nil, errors.New("GetABI returned nil")
-		  }
-		  {{range $pattern, $name := .Libraries}}
-			{{decapitalise $name}}Addr, _, _, _ := Deploy{{capitalise $name}}(auth, backend)
-			{{$contract.Type}}Bin = strings.ReplaceAll({{$contract.Type}}Bin, "__${{$pattern}}$__", {{decapitalise $name}}Addr.String()[2:])
-		  {{end}}
-		  address, tx, contract, err := bind.DeployContract(auth, *parsed, common.FromHex({{.Type}}Bin), backend {{range .Constructor.Inputs}}, {{.Name}}{{end}})
-		  if err != nil {
-		    return common.Address{}, nil, nil, err
-		  }
-		  return address, tx, &{{.Type}}{ {{.Type}}Caller: {{.Type}}Caller{contract: contract}, {{.Type}}Transactor: {{.Type}}Transactor{contract: contract}, {{.Type}}Filterer: {{.Type}}Filterer{contract: contract} }, nil
-		}
-	{{end}}
-
-	// {{.Type}} is an auto generated Go binding around an Ethereum contract.
-	type {{.Type}} struct {
-	  {{.Type}}Caller     // Read-only binding to the contract
-	  {{.Type}}Transactor // Write-only binding to the contract
-	  {{.Type}}Filterer   // Log filterer for contract events
-	}
-
-	// {{.Type}}Caller is an auto generated read-only Go binding around an Ethereum contract.
-	type {{.Type}}Caller struct {
-	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
-	}
-
-	// {{.Type}}Transactor is an auto generated write-only Go binding around an Ethereum contract.
-	type {{.Type}}Transactor struct {
-	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
-	}
-
-	// {{.Type}}Filterer is an auto generated log filtering Go binding around an Ethereum contract events.
-	type {{.Type}}Filterer struct {
-	  contract *bind.BoundContract // Generic contract wrapper for the low level calls
-	}
-
-	// {{.Type}}Session is an auto generated Go binding around an Ethereum contract,
-	// with pre-set call and transact options.
-	type {{.Type}}Session struct {
-	  Contract     *{{.Type}}        // Generic contract binding to set the session for
-	  CallOpts     bind.CallOpts     // Call options to use throughout this session
-	  TransactOpts bind.TransactOpts // Transaction auth options to use throughout this session
-	}
-
-	// {{.Type}}CallerSession is an auto generated read-only Go binding around an Ethereum contract,
-	// with pre-set call options.
-	type {{.Type}}CallerSession struct {
-	  Contract *{{.Type}}Caller // Generic contract caller binding to set the session for
-	  CallOpts bind.CallOpts    // Call options to use throughout this session
-	}
-
-	// {{.Type}}TransactorSession is an auto generated write-only Go binding around an Ethereum contract,
-	// with pre-set transact options.
-	type {{.Type}}TransactorSession struct {
-	  Contract     *{{.Type}}Transactor // Generic contract transactor binding to set the session for
-	  TransactOpts bind.TransactOpts    // Transaction auth options to use throughout this session
-	}
-
-	// {{.Type}}Raw is an auto generated low-level Go binding around an Ethereum contract.
-	type {{.Type}}Raw struct {
-	  Contract *{{.Type}} // Generic contract binding to access the raw methods on
-	}
-
-	// {{.Type}}CallerRaw is an auto generated low-level read-only Go binding around an Ethereum contract.
-	type {{.Type}}CallerRaw struct {
-		Contract *{{.Type}}Caller // Generic read-only contract binding to access the raw methods on
-	}
-
-	// {{.Type}}TransactorRaw is an auto generated low-level write-only Go binding around an Ethereum contract.
-	type {{.Type}}TransactorRaw struct {
-		Contract *{{.Type}}Transactor // Generic write-only contract binding to access the raw methods on
-	}
-
-	// New{{.Type}} creates a new instance of {{.Type}}, bound to a specific deployed contract.
-	func New{{.Type}}(address common.Address, backend bind.ContractBackend) (*{{.Type}}, error) {
-	  contract, err := bind{{.Type}}(address, backend, backend, backend)
-	  if err != nil {
-	    return nil, err
-	  }
-	  return &{{.Type}}{ {{.Type}}Caller: {{.Type}}Caller{contract: contract}, {{.Type}}Transactor: {{.Type}}Transactor{contract: contract}, {{.Type}}Filterer: {{.Type}}Filterer{contract: contract} }, nil
-	}
-
-	// New{{.Type}}Caller creates a new read-only instance of {{.Type}}, bound to a specific deployed contract.
-	func New{{.Type}}Caller(address common.Address, caller bind.ContractCaller) (*{{.Type}}Caller, error) {
-	  contract, err := bind{{.Type}}(address, caller, nil, nil)
-	  if err != nil {
-	    return nil, err
-	  }
-	  return &{{.Type}}Caller{contract: contract}, nil
-	}
-
-	// New{{.Type}}Transactor creates a new write-only instance of {{.Type}}, bound to a specific deployed contract.
-	func New{{.Type}}Transactor(address common.Address, transactor bind.ContractTransactor) (*{{.Type}}Transactor, error) {
-	  contract, err := bind{{.Type}}(address, nil, transactor, nil)
-	  if err != nil {
-	    return nil, err
-	  }
-	  return &{{.Type}}Transactor{contract: contract}, nil
-	}
-
-	// New{{.Type}}Filterer creates a new log filterer instance of {{.Type}}, bound to a specific deployed contract.
- 	func New{{.Type}}Filterer(address common.Address, filterer bind.ContractFilterer) (*{{.Type}}Filterer, error) {
- 	  contract, err := bind{{.Type}}(address, nil, nil, filterer)
- 	  if err != nil {
- 	    return nil, err
- 	  }
- 	  return &{{.Type}}Filterer{contract: contract}, nil
- 	}
-
-	// bind{{.Type}} binds a generic wrapper to an already deployed contract.
-	func bind{{.Type}}(address common.Address, caller bind.ContractCaller, transactor bind.ContractTransactor, filterer bind.ContractFilterer) (*bind.BoundContract, error) {
-	  parsed, err := {{.Type}}MetaData.GetAbi()
-	  if err != nil {
-	    return nil, err
-	  }
-	  return bind.NewBoundContract(address, *parsed, caller, transactor, filterer), nil
-	}
-
-	// Call invokes the (constant) contract method with params as input values and
-	// sets the output to result. The result type might be a single field for simple
-	// returns, a slice of interfaces for anonymous returns and a struct for named
-	// returns.
-	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Call(opts *bind.CallOpts, result *[]interface{}, method string, params ...interface{}) error {
-		return _{{$contract.Type}}.Contract.{{$contract.Type}}Caller.contract.Call(opts, result, method, params...)
-	}
-
-	// Transfer initiates a plain transaction to move funds to the contract, calling
-	// its default method if one is available.
-	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Transfer(opts *bind.TransactOpts) (*types.Transaction, error) {
-		return _{{$contract.Type}}.Contract.{{$contract.Type}}Transactor.contract.Transfer(opts)
-	}
-
-	// Transact invokes the (paid) contract method with params as input values.
-	func (_{{$contract.Type}} *{{$contract.Type}}Raw) Transact(opts *bind.TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
-		return _{{$contract.Type}}.Contract.{{$contract.Type}}Transactor.contract.Transact(opts, method, params...)
-	}
-
-	// Call invokes the (constant) contract method with params as input values and
-	// sets the output to result. The result type might be a single field for simple
-	// returns, a slice of interfaces for anonymous returns and a struct for named
-	// returns.
-	func (_{{$contract.Type}} *{{$contract.Type}}CallerRaw) Call(opts *bind.CallOpts, result *[]interface{}, method string, params ...interface{}) error {
-		return _{{$contract.Type}}.Contract.contract.Call(opts, result, method, params...)
-	}
-
-	// Transfer initiates a plain transaction to move funds to the contract, calling
-	// its default method if one is available.
-	func (_{{$contract.Type}} *{{$contract.Type}}TransactorRaw) Transfer(opts *bind.TransactOpts) (*types.Transaction, error) {
-		return _{{$contract.Type}}.Contract.contract.Transfer(opts)
-	}
-
-	// Transact invokes the (paid) contract method with params as input values.
-	func (_{{$contract.Type}} *{{$contract.Type}}TransactorRaw) Transact(opts *bind.TransactOpts, method string, params ...interface{}) (*types.Transaction, error) {
-		return _{{$contract.Type}}.Contract.contract.Transact(opts, method, params...)
-	}
-
-	{{range .Calls}}
-		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Caller) {{.Normalized.Name}}(opts *bind.CallOpts {{range .Normalized.Inputs}}, {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} },{{else}}{{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}}{{end}} error) {
-			var out []interface{}
-			err := _{{$contract.Type}}.contract.Call(opts, &out, "{{.Original.Name}}" {{range .Normalized.Inputs}}, {{.Name}}{{end}})
-			{{if .Structured}}
-			outstruct := new(struct{ {{range .Normalized.Outputs}} {{.Name}} {{bindtype .Type $structs}}; {{end}} })
-			if err != nil {
-				return *outstruct, err
-			}
-			{{range $i, $t := .Normalized.Outputs}} 
-			outstruct.{{.Name}} = *abi.ConvertType(out[{{$i}}], new({{bindtype .Type $structs}})).(*{{bindtype .Type $structs}}){{end}}
-
-			return *outstruct, err
-			{{else}}
-			if err != nil {
-				return {{range $i, $_ := .Normalized.Outputs}}*new({{bindtype .Type $structs}}), {{end}} err
-			}
-			{{range $i, $t := .Normalized.Outputs}}
-			out{{$i}} := *abi.ConvertType(out[{{$i}}], new({{bindtype .Type $structs}})).(*{{bindtype .Type $structs}}){{end}}
-			
-			return {{range $i, $t := .Normalized.Outputs}}out{{$i}}, {{end}} err
-			{{end}}
-		}
-
-		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Session) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} }, {{else}} {{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}} {{end}} error) {
-		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.CallOpts {{range .Normalized.Inputs}}, {{.Name}}{{end}})
-		}
-
-		// {{.Normalized.Name}} is a free data retrieval call binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}CallerSession) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) ({{if .Structured}}struct{ {{range .Normalized.Outputs}}{{.Name}} {{bindtype .Type $structs}};{{end}} }, {{else}} {{range .Normalized.Outputs}}{{bindtype .Type $structs}},{{end}} {{end}} error) {
-		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.CallOpts {{range .Normalized.Inputs}}, {{.Name}}{{end}})
-		}
-	{{end}}
-
-	{{range .Transacts}}
-		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) {{.Normalized.Name}}(opts *bind.TransactOpts {{range .Normalized.Inputs}}, {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
-			return _{{$contract.Type}}.contract.Transact(opts, "{{.Original.Name}}" {{range .Normalized.Inputs}}, {{.Name}}{{end}})
-		}
-
-		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Session) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.TransactOpts {{range $i, $_ := .Normalized.Inputs}}, {{.Name}}{{end}})
-		}
-
-		// {{.Normalized.Name}} is a paid mutator transaction binding the contract method 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) {{.Normalized.Name}}({{range $i, $_ := .Normalized.Inputs}}{{if ne $i 0}},{{end}} {{.Name}} {{bindtype .Type $structs}} {{end}}) (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.{{.Normalized.Name}}(&_{{$contract.Type}}.TransactOpts {{range $i, $_ := .Normalized.Inputs}}, {{.Name}}{{end}})
-		}
-	{{end}}
-
-	{{if .Fallback}} 
-		// Fallback is a paid mutator transaction binding the contract fallback function.
-		//
-		// Solidity: {{.Fallback.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) Fallback(opts *bind.TransactOpts, calldata []byte) (*types.Transaction, error) {
-			return _{{$contract.Type}}.contract.RawTransact(opts, calldata)
-		}
-
-		// Fallback is a paid mutator transaction binding the contract fallback function.
-		//
-		// Solidity: {{.Fallback.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Session) Fallback(calldata []byte) (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.Fallback(&_{{$contract.Type}}.TransactOpts, calldata)
-		}
-	
-		// Fallback is a paid mutator transaction binding the contract fallback function.
-		// 
-		// Solidity: {{.Fallback.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) Fallback(calldata []byte) (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.Fallback(&_{{$contract.Type}}.TransactOpts, calldata)
-		}
-	{{end}}
-
-	{{if .Receive}} 
-		// Receive is a paid mutator transaction binding the contract receive function.
-		//
-		// Solidity: {{.Receive.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Transactor) Receive(opts *bind.TransactOpts) (*types.Transaction, error) {
-			return _{{$contract.Type}}.contract.RawTransact(opts, nil) // calldata is disallowed for receive function
-		}
-
-		// Receive is a paid mutator transaction binding the contract receive function.
-		//
-		// Solidity: {{.Receive.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Session) Receive() (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.Receive(&_{{$contract.Type}}.TransactOpts)
-		}
-	
-		// Receive is a paid mutator transaction binding the contract receive function.
-		// 
-		// Solidity: {{.Receive.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}TransactorSession) Receive() (*types.Transaction, error) {
-		  return _{{$contract.Type}}.Contract.Receive(&_{{$contract.Type}}.TransactOpts)
-		}
-	{{end}}
-
-	{{range .Events}}
-		// {{$contract.Type}}{{.Normalized.Name}}Iterator is returned from Filter{{.Normalized.Name}} and is used to iterate over the raw logs and unpacked data for {{.Normalized.Name}} events raised by the {{$contract.Type}} contract.
-		type {{$contract.Type}}{{.Normalized.Name}}Iterator struct {
-			Event *{{$contract.Type}}{{.Normalized.Name}} // Event containing the contract specifics and raw log
-
-			contract *bind.BoundContract // Generic contract to use for unpacking event data
-			event    string              // Event name to use for unpacking event data
-
-			logs chan types.Log        // Log channel receiving the found contract events
-			sub  ethereum.Subscription // Subscription for errors, completion and termination
-			done bool                  // Whether the subscription completed delivering logs
-			fail error                 // Occurred error to stop iteration
-		}
-		// Next advances the iterator to the subsequent event, returning whether there
-		// are any more events found. In case of a retrieval or parsing error, false is
-		// returned and Error() can be queried for the exact failure.
-		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Next() bool {
-			// If the iterator failed, stop iterating
-			if (it.fail != nil) {
-				return false
-			}
-			// If the iterator completed, deliver directly whatever's available
-			if (it.done) {
-				select {
-				case log := <-it.logs:
-					it.Event = new({{$contract.Type}}{{.Normalized.Name}})
-					if err := it.contract.UnpackLog(it.Event, it.event, log); err != nil {
-						it.fail = err
-						return false
-					}
-					it.Event.Raw = log
-					return true
-
-				default:
-					return false
-				}
-			}
-			// Iterator still in progress, wait for either a data or an error event
-			select {
-			case log := <-it.logs:
-				it.Event = new({{$contract.Type}}{{.Normalized.Name}})
-				if err := it.contract.UnpackLog(it.Event, it.event, log); err != nil {
-					it.fail = err
-					return false
-				}
-				it.Event.Raw = log
-				return true
-
-			case err := <-it.sub.Err():
-				it.done = true
-				it.fail = err
-				return it.Next()
-			}
-		}
-		// Error returns any retrieval or parsing error occurred during filtering.
-		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Error() error {
-			return it.fail
-		}
-		// Close terminates the iteration process, releasing any pending underlying
-		// resources.
-		func (it *{{$contract.Type}}{{.Normalized.Name}}Iterator) Close() error {
-			it.sub.Unsubscribe()
-			return nil
-		}
-
-		// {{$contract.Type}}{{.Normalized.Name}} represents a {{.Normalized.Name}} event raised by the {{$contract.Type}} contract.
-		type {{$contract.Type}}{{.Normalized.Name}} struct { {{range .Normalized.Inputs}}
-			{{capitalise .Name}} {{if .Indexed}}{{bindtopictype .Type $structs}}{{else}}{{bindtype .Type $structs}}{{end}}; {{end}}
-			Raw types.Log // Blockchain specific contextual infos
-		}
-
-		// Filter{{.Normalized.Name}} is a free log retrieval operation binding the contract event 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
- 		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Filter{{.Normalized.Name}}(opts *bind.FilterOpts{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}} []{{bindtype .Type $structs}}{{end}}{{end}}) (*{{$contract.Type}}{{.Normalized.Name}}Iterator, error) {
-			{{range .Normalized.Inputs}}
-			{{if .Indexed}}var {{.Name}}Rule []interface{}
-			for _, {{.Name}}Item := range {{.Name}} {
-				{{.Name}}Rule = append({{.Name}}Rule, {{.Name}}Item)
-			}{{end}}{{end}}
-
-			logs, sub, err := _{{$contract.Type}}.contract.FilterLogs(opts, "{{.Original.Name}}"{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}}Rule{{end}}{{end}})
-			if err != nil {
-				return nil, err
-			}
-			return &{{$contract.Type}}{{.Normalized.Name}}Iterator{contract: _{{$contract.Type}}.contract, event: "{{.Original.Name}}", logs: logs, sub: sub}, nil
- 		}
-
-		// Watch{{.Normalized.Name}} is a free log subscription operation binding the contract event 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Watch{{.Normalized.Name}}(opts *bind.WatchOpts, sink chan<- *{{$contract.Type}}{{.Normalized.Name}}{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}} []{{bindtype .Type $structs}}{{end}}{{end}}) (event.Subscription, error) {
-			{{range .Normalized.Inputs}}
-			{{if .Indexed}}var {{.Name}}Rule []interface{}
-			for _, {{.Name}}Item := range {{.Name}} {
-				{{.Name}}Rule = append({{.Name}}Rule, {{.Name}}Item)
-			}{{end}}{{end}}
-
-			logs, sub, err := _{{$contract.Type}}.contract.WatchLogs(opts, "{{.Original.Name}}"{{range .Normalized.Inputs}}{{if .Indexed}}, {{.Name}}Rule{{end}}{{end}})
-			if err != nil {
-				return nil, err
-			}
-			return event.NewSubscription(func(quit <-chan struct{}) error {
-				defer sub.Unsubscribe()
-				for {
-					select {
-					case log := <-logs:
-						// New log arrived, parse the event and forward to the user
-						event := new({{$contract.Type}}{{.Normalized.Name}})
-						if err := _{{$contract.Type}}.contract.UnpackLog(event, "{{.Original.Name}}", log); err != nil {
-							return err
-						}
-						event.Raw = log
-
-						select {
-						case sink <- event:
-						case err := <-sub.Err():
-							return err
-						case <-quit:
-							return nil
-						}
-					case err := <-sub.Err():
-						return err
-					case <-quit:
-						return nil
-					}
-				}
-			}), nil
-		}
-
-		// Parse{{.Normalized.Name}} is a log parse operation binding the contract event 0x{{printf "%x" .Original.ID}}.
-		//
-		// Solidity: {{.Original.String}}
-		func (_{{$contract.Type}} *{{$contract.Type}}Filterer) Parse{{.Normalized.Name}}(log types.Log) (*{{$contract.Type}}{{.Normalized.Name}}, error) {
-			event := new({{$contract.Type}}{{.Normalized.Name}})
-			if err := _{{$contract.Type}}.contract.UnpackLog(event, "{{.Original.Name}}", log); err != nil {
-				return nil, err
-			}
-			event.Raw = log
-			return event, nil
-		}
-
- 	{{end}}
-{{end}}
-`
+//
+//go:embed source.go.tpl
+var tmplSourceGo string

accounts/abi/bind/util_test.go

@@ -24,11 +24,11 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/accounts/abi/bind"
-	"github.com/ethereum/go-ethereum/accounts/abi/bind/backends"
 	"github.com/ethereum/go-ethereum/common"
-	"github.com/ethereum/go-ethereum/core"
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/ethclient/simulated"
+	"github.com/ethereum/go-ethereum/params"
 )
 
 var testKey, _ = crypto.HexToECDSA("b71c71a67e1177ad4e901695e1b4b9ee17ae16c6668d313eac2f96dbcda3f291")
@@ -53,21 +53,21 @@ var waitDeployedTests = map[string]struct {
 }
 
 func TestWaitDeployed(t *testing.T) {
+	t.Parallel()
 	for name, test := range waitDeployedTests {
-		backend := backends.NewSimulatedBackend(
-			core.GenesisAlloc{
+		backend := simulated.NewBackend(
+			types.GenesisAlloc{
 				crypto.PubkeyToAddress(testKey.PublicKey): {Balance: big.NewInt(10000000000000000)},
 			},
-			10000000,
 		)
 		defer backend.Close()
 
 		// Create the transaction
-		head, _ := backend.HeaderByNumber(context.Background(), nil) // Should be child's, good enough
-		gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(1))
+		head, _ := backend.Client().HeaderByNumber(context.Background(), nil) // Should be child's, good enough
+		gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(params.GWei))
 
 		tx := types.NewContractCreation(0, big.NewInt(0), test.gas, gasPrice, common.FromHex(test.code))
-		tx, _ = types.SignTx(tx, types.HomesteadSigner{}, testKey)
+		tx, _ = types.SignTx(tx, types.LatestSignerForChainID(big.NewInt(1337)), testKey)
 
 		// Wait for it to get mined in the background.
 		var (
@@ -77,12 +77,12 @@ func TestWaitDeployed(t *testing.T) {
 			ctx     = context.Background()
 		)
 		go func() {
-			address, err = bind.WaitDeployed(ctx, backend, tx)
+			address, err = bind.WaitDeployed(ctx, backend.Client(), tx)
 			close(mined)
 		}()
 
 		// Send and mine the transaction.
-		backend.SendTransaction(ctx, tx)
+		backend.Client().SendTransaction(ctx, tx)
 		backend.Commit()
 
 		select {
@@ -100,41 +100,40 @@ func TestWaitDeployed(t *testing.T) {
 }
 
 func TestWaitDeployedCornerCases(t *testing.T) {
-	backend := backends.NewSimulatedBackend(
-		core.GenesisAlloc{
+	backend := simulated.NewBackend(
+		types.GenesisAlloc{
 			crypto.PubkeyToAddress(testKey.PublicKey): {Balance: big.NewInt(10000000000000000)},
 		},
-		10000000,
 	)
 	defer backend.Close()
 
-	head, _ := backend.HeaderByNumber(context.Background(), nil) // Should be child's, good enough
+	head, _ := backend.Client().HeaderByNumber(context.Background(), nil) // Should be child's, good enough
 	gasPrice := new(big.Int).Add(head.BaseFee, big.NewInt(1))
 
 	// Create a transaction to an account.
 	code := "6060604052600a8060106000396000f360606040526008565b00"
 	tx := types.NewTransaction(0, common.HexToAddress("0x01"), big.NewInt(0), 3000000, gasPrice, common.FromHex(code))
-	tx, _ = types.SignTx(tx, types.HomesteadSigner{}, testKey)
+	tx, _ = types.SignTx(tx, types.LatestSigner(params.AllDevChainProtocolChanges), testKey)
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	backend.SendTransaction(ctx, tx)
+	backend.Client().SendTransaction(ctx, tx)
 	backend.Commit()
-	notContentCreation := errors.New("tx is not contract creation")
-	if _, err := bind.WaitDeployed(ctx, backend, tx); err.Error() != notContentCreation.Error() {
-		t.Errorf("error missmatch: want %q, got %q, ", notContentCreation, err)
+	notContractCreation := errors.New("tx is not contract creation")
+	if _, err := bind.WaitDeployed(ctx, backend.Client(), tx); err.Error() != notContractCreation.Error() {
+		t.Errorf("error mismatch: want %q, got %q, ", notContractCreation, err)
 	}
 
 	// Create a transaction that is not mined.
 	tx = types.NewContractCreation(1, big.NewInt(0), 3000000, gasPrice, common.FromHex(code))
-	tx, _ = types.SignTx(tx, types.HomesteadSigner{}, testKey)
+	tx, _ = types.SignTx(tx, types.LatestSigner(params.AllDevChainProtocolChanges), testKey)
 
 	go func() {
 		contextCanceled := errors.New("context canceled")
-		if _, err := bind.WaitDeployed(ctx, backend, tx); err.Error() != contextCanceled.Error() {
-			t.Errorf("error missmatch: want %q, got %q, ", contextCanceled, err)
+		if _, err := bind.WaitDeployed(ctx, backend.Client(), tx); err.Error() != contextCanceled.Error() {
+			t.Errorf("error mismatch: want %q, got %q, ", contextCanceled, err)
 		}
 	}()
 
-	backend.SendTransaction(ctx, tx)
+	backend.Client().SendTransaction(ctx, tx)
 	cancel()
 }

accounts/abi/error.go

@@ -18,7 +18,6 @@ package abi
 
 import (
 	"bytes"
-	"errors"
 	"fmt"
 	"strings"
 
@@ -32,7 +31,7 @@ type Error struct {
 	str    string
 
 	// Sig contains the string signature according to the ABI spec.
-	// e.g.	 error foo(uint32 a, int b) = "foo(uint32,int256)"
+	// e.g. error foo(uint32 a, int b) = "foo(uint32,int256)"
 	// Please note that "int" is substitute for its canonical representation "int256"
 	Sig string
 
@@ -78,16 +77,16 @@ func NewError(name string, inputs Arguments) Error {
 	}
 }
 
-func (e *Error) String() string {
+func (e Error) String() string {
 	return e.str
 }
 
 func (e *Error) Unpack(data []byte) (interface{}, error) {
 	if len(data) < 4 {
-		return "", errors.New("invalid data for unpacking")
+		return "", fmt.Errorf("insufficient data for unpacking: have %d, want at least 4", len(data))
 	}
 	if !bytes.Equal(data[:4], e.ID[:4]) {
-		return "", errors.New("invalid data for unpacking")
+		return "", fmt.Errorf("invalid identifier, have %#x want %#x", data[:4], e.ID[:4])
 	}
 	return e.Inputs.Unpack(data[4:])
 }

accounts/abi/event_test.go

@@ -81,6 +81,7 @@ var pledgeData1 = "00000000000000000000000000ce0d46d924cc8437c806721496599fc3ffa
 var mixedCaseData1 = "00000000000000000000000000000000000000000000000000000000000f42400000000000000000000000000000000000000000000000000000020489e8000000000000000000000000000000000000000000000000000000000000000f4241"
 
 func TestEventId(t *testing.T) {
+	t.Parallel()
 	var table = []struct {
 		definition   string
 		expectations map[string]common.Hash
@@ -112,6 +113,7 @@ func TestEventId(t *testing.T) {
 }
 
 func TestEventString(t *testing.T) {
+	t.Parallel()
 	var table = []struct {
 		definition   string
 		expectations map[string]string
@@ -146,6 +148,7 @@ func TestEventString(t *testing.T) {
 
 // TestEventMultiValueWithArrayUnpack verifies that array fields will be counted after parsing array.
 func TestEventMultiValueWithArrayUnpack(t *testing.T) {
+	t.Parallel()
 	definition := `[{"name": "test", "type": "event", "inputs": [{"indexed": false, "name":"value1", "type":"uint8[2]"},{"indexed": false, "name":"value2", "type":"uint8"}]}]`
 	abi, err := JSON(strings.NewReader(definition))
 	require.NoError(t, err)
@@ -161,6 +164,7 @@ func TestEventMultiValueWithArrayUnpack(t *testing.T) {
 }
 
 func TestEventTupleUnpack(t *testing.T) {
+	t.Parallel()
 	type EventTransfer struct {
 		Value *big.Int
 	}
@@ -351,6 +355,7 @@ func unpackTestEventData(dest interface{}, hexData string, jsonEvent []byte, ass
 
 // TestEventUnpackIndexed verifies that indexed field will be skipped by event decoder.
 func TestEventUnpackIndexed(t *testing.T) {
+	t.Parallel()
 	definition := `[{"name": "test", "type": "event", "inputs": [{"indexed": true, "name":"value1", "type":"uint8"},{"indexed": false, "name":"value2", "type":"uint8"}]}]`
 	type testStruct struct {
 		Value1 uint8 // indexed
@@ -368,6 +373,7 @@ func TestEventUnpackIndexed(t *testing.T) {
 
 // TestEventIndexedWithArrayUnpack verifies that decoder will not overflow when static array is indexed input.
 func TestEventIndexedWithArrayUnpack(t *testing.T) {
+	t.Parallel()
 	definition := `[{"name": "test", "type": "event", "inputs": [{"indexed": true, "name":"value1", "type":"uint8[2]"},{"indexed": false, "name":"value2", "type":"string"}]}]`
 	type testStruct struct {
 		Value1 [2]uint8 // indexed

accounts/abi/method.go

@@ -117,24 +117,23 @@ func NewMethod(name string, rawName string, funType FunctionType, mutability str
 		sig = fmt.Sprintf("%v(%v)", rawName, strings.Join(types, ","))
 		id = crypto.Keccak256([]byte(sig))[:4]
 	}
-	// Extract meaningful state mutability of solidity method.
-	// If it's default value, never print it.
-	state := mutability
-	if state == "nonpayable" {
-		state = ""
-	}
-	if state != "" {
-		state = state + " "
-	}
 	identity := fmt.Sprintf("function %v", rawName)
-	if funType == Fallback {
+	switch funType {
+	case Fallback:
 		identity = "fallback"
-	} else if funType == Receive {
+	case Receive:
 		identity = "receive"
-	} else if funType == Constructor {
+	case Constructor:
 		identity = "constructor"
 	}
-	str := fmt.Sprintf("%v(%v) %sreturns(%v)", identity, strings.Join(inputNames, ", "), state, strings.Join(outputNames, ", "))
+	var str string
+	// Extract meaningful state mutability of solidity method.
+	// If it's empty string or default value "nonpayable", never print it.
+	if mutability == "" || mutability == "nonpayable" {
+		str = fmt.Sprintf("%v(%v) returns(%v)", identity, strings.Join(inputNames, ", "), strings.Join(outputNames, ", "))
+	} else {
+		str = fmt.Sprintf("%v(%v) %s returns(%v)", identity, strings.Join(inputNames, ", "), mutability, strings.Join(outputNames, ", "))
+	}
 
 	return Method{
 		Name:            name,

accounts/abi/method_test.go

@@ -35,6 +35,7 @@ const methoddata = `
 ]`
 
 func TestMethodString(t *testing.T) {
+	t.Parallel()
 	var table = []struct {
 		method      string
 		expectation string
@@ -84,11 +85,12 @@ func TestMethodString(t *testing.T) {
 
 	for _, test := range table {
 		var got string
-		if test.method == "fallback" {
+		switch test.method {
+		case "fallback":
 			got = abi.Fallback.String()
-		} else if test.method == "receive" {
+		case "receive":
 			got = abi.Receive.String()
-		} else {
+		default:
 			got = abi.Methods[test.method].String()
 		}
 		if got != test.expectation {
@@ -98,6 +100,7 @@ func TestMethodString(t *testing.T) {
 }
 
 func TestMethodSig(t *testing.T) {
+	t.Parallel()
 	var cases = []struct {
 		method string
 		expect string

accounts/abi/pack.go

@@ -57,7 +57,7 @@ func packElement(t Type, reflectValue reflect.Value) ([]byte, error) {
 			reflectValue = mustArrayToByteSlice(reflectValue)
 		}
 		if reflectValue.Type() != reflect.TypeOf([]byte{}) {
-			return []byte{}, errors.New("Bytes type is neither slice nor array")
+			return []byte{}, errors.New("bytes type is neither slice nor array")
 		}
 		return packBytesSlice(reflectValue.Bytes(), reflectValue.Len()), nil
 	case FixedBytesTy, FunctionTy:
@@ -66,7 +66,7 @@ func packElement(t Type, reflectValue reflect.Value) ([]byte, error) {
 		}
 		return common.RightPadBytes(reflectValue.Bytes(), 32), nil
 	default:
-		return []byte{}, fmt.Errorf("Could not pack element, unknown type: %v", t.T)
+		return []byte{}, fmt.Errorf("could not pack element, unknown type: %v", t.T)
 	}
 }
 

accounts/abi/pack_test.go

@@ -32,8 +32,11 @@ import (
 
 // TestPack tests the general pack/unpack tests in packing_test.go
 func TestPack(t *testing.T) {
+	t.Parallel()
 	for i, test := range packUnpackTests {
+		i, test := i, test
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
+			t.Parallel()
 			encb, err := hex.DecodeString(test.packed)
 			if err != nil {
 				t.Fatalf("invalid hex %s: %v", test.packed, err)
@@ -57,6 +60,7 @@ func TestPack(t *testing.T) {
 }
 
 func TestMethodPack(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(jsondata))
 	if err != nil {
 		t.Fatal(err)
@@ -177,6 +181,7 @@ func TestMethodPack(t *testing.T) {
 }
 
 func TestPackNumber(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		value  reflect.Value
 		packed []byte

accounts/abi/reflect.go

@@ -24,7 +24,7 @@ import (
 	"strings"
 )
 
-// ConvertType converts an interface of a runtime type into a interface of the
+// ConvertType converts an interface of a runtime type into an interface of the
 // given type, e.g. turn this code:
 //
 //	var fields []reflect.StructField
@@ -33,7 +33,7 @@ import (
 //			Name: "X",
 //			Type: reflect.TypeOf(new(big.Int)),
 //			Tag:  reflect.StructTag("json:\"" + "x" + "\""),
-//	}
+//	})
 //
 // into:
 //
@@ -134,7 +134,7 @@ func setSlice(dst, src reflect.Value) error {
 		dst.Set(slice)
 		return nil
 	}
-	return errors.New("Cannot set slice, destination not settable")
+	return errors.New("cannot set slice, destination not settable")
 }
 
 func setArray(dst, src reflect.Value) error {
@@ -155,7 +155,7 @@ func setArray(dst, src reflect.Value) error {
 		dst.Set(array)
 		return nil
 	}
-	return errors.New("Cannot set array, destination not settable")
+	return errors.New("cannot set array, destination not settable")
 }
 
 func setStruct(dst, src reflect.Value) error {
@@ -163,7 +163,7 @@ func setStruct(dst, src reflect.Value) error {
 		srcField := src.Field(i)
 		dstField := dst.Field(i)
 		if !dstField.IsValid() || !srcField.IsValid() {
-			return fmt.Errorf("Could not find src field: %v value: %v in destination", srcField.Type().Name(), srcField)
+			return fmt.Errorf("could not find src field: %v value: %v in destination", srcField.Type().Name(), srcField)
 		}
 		if err := set(dstField, srcField); err != nil {
 			return err
@@ -228,7 +228,7 @@ func mapArgNamesToStructFields(argNames []string, value reflect.Value) (map[stri
 		structFieldName := ToCamelCase(argName)
 
 		if structFieldName == "" {
-			return nil, fmt.Errorf("abi: purely underscored output cannot unpack to struct")
+			return nil, errors.New("abi: purely underscored output cannot unpack to struct")
 		}
 
 		// this abi has already been paired, skip it... unless there exists another, yet unassigned

accounts/abi/reflect_test.go

@@ -170,8 +170,11 @@ var reflectTests = []reflectTest{
 }
 
 func TestReflectNameToStruct(t *testing.T) {
+	t.Parallel()
 	for _, test := range reflectTests {
+		test := test
 		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
 			m, err := mapArgNamesToStructFields(test.args, reflect.ValueOf(test.struc))
 			if len(test.err) > 0 {
 				if err == nil || err.Error() != test.err {
@@ -192,6 +195,7 @@ func TestReflectNameToStruct(t *testing.T) {
 }
 
 func TestConvertType(t *testing.T) {
+	t.Parallel()
 	// Test Basic Struct
 	type T struct {
 		X *big.Int

accounts/abi/selector_parser.go

@@ -17,6 +17,7 @@
 package abi
 
 import (
+	"errors"
 	"fmt"
 )
 
@@ -40,7 +41,7 @@ func isIdentifierSymbol(c byte) bool {
 
 func parseToken(unescapedSelector string, isIdent bool) (string, string, error) {
 	if len(unescapedSelector) == 0 {
-		return "", "", fmt.Errorf("empty token")
+		return "", "", errors.New("empty token")
 	}
 	firstChar := unescapedSelector[0]
 	position := 1
@@ -110,7 +111,7 @@ func parseCompositeType(unescapedSelector string) ([]interface{}, string, error)
 
 func parseType(unescapedSelector string) (interface{}, string, error) {
 	if len(unescapedSelector) == 0 {
-		return nil, "", fmt.Errorf("empty type")
+		return nil, "", errors.New("empty type")
 	}
 	if unescapedSelector[0] == '(' {
 		return parseCompositeType(unescapedSelector)

accounts/abi/selector_parser_test.go

@@ -24,6 +24,7 @@ import (
 )
 
 func TestParseSelector(t *testing.T) {
+	t.Parallel()
 	mkType := func(types ...interface{}) []ArgumentMarshaling {
 		var result []ArgumentMarshaling
 		for i, typeOrComponents := range types {

accounts/abi/topics.go

@@ -24,6 +24,7 @@ import (
 	"reflect"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/math"
 	"github.com/ethereum/go-ethereum/crypto"
 )
 
@@ -41,8 +42,7 @@ func MakeTopics(query ...[]interface{}) ([][]common.Hash, error) {
 			case common.Address:
 				copy(topic[common.HashLength-common.AddressLength:], rule[:])
 			case *big.Int:
-				blob := rule.Bytes()
-				copy(topic[common.HashLength-len(blob):], blob)
+				copy(topic[:], math.U256Bytes(rule))
 			case bool:
 				if rule {
 					topic[common.HashLength-1] = 1
@@ -75,7 +75,7 @@ func MakeTopics(query ...[]interface{}) ([][]common.Hash, error) {
 				copy(topic[:], hash[:])
 
 			default:
-				// todo(rjl493456442) according solidity documentation, indexed event
+				// todo(rjl493456442) according to solidity documentation, indexed event
 				// parameters that are not value types i.e. arrays and structs are not
 				// stored directly but instead a keccak256-hash of an encoding is stored.
 				//

accounts/abi/topics_test.go

@@ -17,6 +17,7 @@
 package abi
 
 import (
+	"math"
 	"math/big"
 	"reflect"
 	"testing"
@@ -26,6 +27,7 @@ import (
 )
 
 func TestMakeTopics(t *testing.T) {
+	t.Parallel()
 	type args struct {
 		query [][]interface{}
 	}
@@ -54,9 +56,27 @@ func TestMakeTopics(t *testing.T) {
 			false,
 		},
 		{
-			"support *big.Int types in topics",
-			args{[][]interface{}{{big.NewInt(1).Lsh(big.NewInt(2), 254)}}},
-			[][]common.Hash{{common.Hash{128}}},
+			"support positive *big.Int types in topics",
+			args{[][]interface{}{
+				{big.NewInt(1)},
+				{big.NewInt(1).Lsh(big.NewInt(2), 254)},
+			}},
+			[][]common.Hash{
+				{common.HexToHash("0000000000000000000000000000000000000000000000000000000000000001")},
+				{common.Hash{128}},
+			},
+			false,
+		},
+		{
+			"support negative *big.Int types in topics",
+			args{[][]interface{}{
+				{big.NewInt(-1)},
+				{big.NewInt(math.MinInt64)},
+			}},
+			[][]common.Hash{
+				{common.MaxHash},
+				{common.HexToHash("ffffffffffffffffffffffffffffffffffffffffffffffff8000000000000000")},
+			},
 			false,
 		},
 		{
@@ -117,7 +137,9 @@ func TestMakeTopics(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
+		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
 			got, err := MakeTopics(tt.args.query...)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("makeTopics() error = %v, wantErr %v", err, tt.wantErr)
@@ -347,10 +369,13 @@ func setupTopicsTests() []topicTest {
 }
 
 func TestParseTopics(t *testing.T) {
+	t.Parallel()
 	tests := setupTopicsTests()
 
 	for _, tt := range tests {
+		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
 			createObj := tt.args.createObj()
 			if err := ParseTopics(createObj, tt.args.fields, tt.args.topics); (err != nil) != tt.wantErr {
 				t.Errorf("parseTopics() error = %v, wantErr %v", err, tt.wantErr)
@@ -364,10 +389,13 @@ func TestParseTopics(t *testing.T) {
 }
 
 func TestParseTopicsIntoMap(t *testing.T) {
+	t.Parallel()
 	tests := setupTopicsTests()
 
 	for _, tt := range tests {
+		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
+			t.Parallel()
 			outMap := make(map[string]interface{})
 			if err := ParseTopicsIntoMap(outMap, tt.args.fields, tt.args.topics); (err != nil) != tt.wantErr {
 				t.Errorf("parseTopicsIntoMap() error = %v, wantErr %v", err, tt.wantErr)

accounts/abi/type.go

@@ -64,13 +64,16 @@ type Type struct {
 var (
 	// typeRegex parses the abi sub types
 	typeRegex = regexp.MustCompile("([a-zA-Z]+)(([0-9]+)(x([0-9]+))?)?")
+
+	// sliceSizeRegex grab the slice size
+	sliceSizeRegex = regexp.MustCompile("[0-9]+")
 )
 
 // NewType creates a new reflection type of abi type given in t.
 func NewType(t string, internalType string, components []ArgumentMarshaling) (typ Type, err error) {
 	// check that array brackets are equal if they exist
 	if strings.Count(t, "[") != strings.Count(t, "]") {
-		return Type{}, fmt.Errorf("invalid arg type in abi")
+		return Type{}, errors.New("invalid arg type in abi")
 	}
 	typ.stringKind = t
 
@@ -91,8 +94,7 @@ func NewType(t string, internalType string, components []ArgumentMarshaling) (ty
 		// grab the last cell and create a type from there
 		sliced := t[i:]
 		// grab the slice size with regexp
-		re := regexp.MustCompile("[0-9]+")
-		intz := re.FindAllString(sliced, -1)
+		intz := sliceSizeRegex.FindAllString(sliced, -1)
 
 		if len(intz) == 0 {
 			// is a slice
@@ -109,7 +111,7 @@ func NewType(t string, internalType string, components []ArgumentMarshaling) (ty
 			}
 			typ.stringKind = embeddedType.stringKind + sliced
 		} else {
-			return Type{}, fmt.Errorf("invalid formatting of array type")
+			return Type{}, errors.New("invalid formatting of array type")
 		}
 		return typ, err
 	}
@@ -179,9 +181,6 @@ func NewType(t string, internalType string, components []ArgumentMarshaling) (ty
 				return Type{}, errors.New("abi: purely anonymous or underscored field is not supported")
 			}
 			fieldName := ResolveNameConflict(name, func(s string) bool { return used[s] })
-			if err != nil {
-				return Type{}, err
-			}
 			used[fieldName] = true
 			if !isValidFieldName(fieldName) {
 				return Type{}, fmt.Errorf("field %d has invalid name", idx)
@@ -348,7 +347,7 @@ func (t Type) pack(v reflect.Value) ([]byte, error) {
 	}
 }
 
-// requireLengthPrefix returns whether the type requires any sort of length
+// requiresLengthPrefix returns whether the type requires any sort of length
 // prefixing.
 func (t Type) requiresLengthPrefix() bool {
 	return t.T == StringTy || t.T == BytesTy || t.T == SliceTy

accounts/abi/type_test.go

@@ -25,12 +25,13 @@ import (
 	"github.com/ethereum/go-ethereum/common"
 )
 
-// typeWithoutStringer is a alias for the Type type which simply doesn't implement
+// typeWithoutStringer is an alias for the Type type which simply doesn't implement
 // the stringer interface to allow printing type details in the tests below.
 type typeWithoutStringer Type
 
 // Tests that all allowed types get recognized by the type parser.
 func TestTypeRegexp(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		blob       string
 		components []ArgumentMarshaling
@@ -117,6 +118,7 @@ func TestTypeRegexp(t *testing.T) {
 }
 
 func TestTypeCheck(t *testing.T) {
+	t.Parallel()
 	for i, test := range []struct {
 		typ        string
 		components []ArgumentMarshaling
@@ -308,6 +310,7 @@ func TestTypeCheck(t *testing.T) {
 }
 
 func TestInternalType(t *testing.T) {
+	t.Parallel()
 	components := []ArgumentMarshaling{{Name: "a", Type: "int64"}}
 	internalType := "struct a.b[]"
 	kind := Type{
@@ -332,6 +335,7 @@ func TestInternalType(t *testing.T) {
 }
 
 func TestGetTypeSize(t *testing.T) {
+	t.Parallel()
 	var testCases = []struct {
 		typ        string
 		components []ArgumentMarshaling
@@ -368,6 +372,7 @@ func TestGetTypeSize(t *testing.T) {
 }
 
 func TestNewFixedBytesOver32(t *testing.T) {
+	t.Parallel()
 	_, err := NewType("bytes4096", "", nil)
 	if err == nil {
 		t.Errorf("fixed bytes with size over 32 is not spec'd")

accounts/abi/unpack.go

@@ -18,6 +18,7 @@ package abi
 
 import (
 	"encoding/binary"
+	"errors"
 	"fmt"
 	"math"
 	"math/big"
@@ -125,7 +126,7 @@ func readBool(word []byte) (bool, error) {
 // readFunctionType enforces that standard by always presenting it as a 24-array (address + sig = 24 bytes)
 func readFunctionType(t Type, word []byte) (funcTy [24]byte, err error) {
 	if t.T != FunctionTy {
-		return [24]byte{}, fmt.Errorf("abi: invalid type in call to make function type byte array")
+		return [24]byte{}, errors.New("abi: invalid type in call to make function type byte array")
 	}
 	if garbage := binary.BigEndian.Uint64(word[24:32]); garbage != 0 {
 		err = fmt.Errorf("abi: got improperly encoded function type, got %v", word)
@@ -138,7 +139,7 @@ func readFunctionType(t Type, word []byte) (funcTy [24]byte, err error) {
 // ReadFixedBytes uses reflection to create a fixed array to be read from.
 func ReadFixedBytes(t Type, word []byte) (interface{}, error) {
 	if t.T != FixedBytesTy {
-		return nil, fmt.Errorf("abi: invalid type in call to make fixed byte array")
+		return nil, errors.New("abi: invalid type in call to make fixed byte array")
 	}
 	// convert
 	array := reflect.New(t.GetType()).Elem()
@@ -159,14 +160,15 @@ func forEachUnpack(t Type, output []byte, start, size int) (interface{}, error)
 	// this value will become our slice or our array, depending on the type
 	var refSlice reflect.Value
 
-	if t.T == SliceTy {
+	switch t.T {
+	case SliceTy:
 		// declare our slice
 		refSlice = reflect.MakeSlice(t.GetType(), size, size)
-	} else if t.T == ArrayTy {
+	case ArrayTy:
 		// declare our array
 		refSlice = reflect.New(t.GetType()).Elem()
-	} else {
-		return nil, fmt.Errorf("abi: invalid type in array/slice unpacking stage")
+	default:
+		return nil, errors.New("abi: invalid type in array/slice unpacking stage")
 	}
 
 	// Arrays have packed elements, resulting in longer unpack steps.

accounts/abi/unpack_test.go

@@ -33,6 +33,7 @@ import (
 
 // TestUnpack tests the general pack/unpack tests in packing_test.go
 func TestUnpack(t *testing.T) {
+	t.Parallel()
 	for i, test := range packUnpackTests {
 		t.Run(strconv.Itoa(i)+" "+test.def, func(t *testing.T) {
 			//Unpack
@@ -206,13 +207,13 @@ var unpackTests = []unpackTest{
 		def:  `[{"type":"bool"}]`,
 		enc:  "",
 		want: false,
-		err:  "abi: attempting to unmarshall an empty string while arguments are expected",
+		err:  "abi: attempting to unmarshal an empty string while arguments are expected",
 	},
 	{
 		def:  `[{"type":"bytes32","indexed":true},{"type":"uint256","indexed":false}]`,
 		enc:  "",
 		want: false,
-		err:  "abi: attempting to unmarshall an empty string while arguments are expected",
+		err:  "abi: attempting to unmarshal an empty string while arguments are expected",
 	},
 	{
 		def:  `[{"type":"bool","indexed":true},{"type":"uint64","indexed":true}]`,
@@ -224,6 +225,7 @@ var unpackTests = []unpackTest{
 // TestLocalUnpackTests runs test specially designed only for unpacking.
 // All test cases that can be used to test packing and unpacking should move to packing_test.go
 func TestLocalUnpackTests(t *testing.T) {
+	t.Parallel()
 	for i, test := range unpackTests {
 		t.Run(strconv.Itoa(i), func(t *testing.T) {
 			//Unpack
@@ -251,6 +253,7 @@ func TestLocalUnpackTests(t *testing.T) {
 }
 
 func TestUnpackIntoInterfaceSetDynamicArrayOutput(t *testing.T) {
+	t.Parallel()
 	abi, err := JSON(strings.NewReader(`[{"constant":true,"inputs":[],"name":"testDynamicFixedBytes15","outputs":[{"name":"","type":"bytes15[]"}],"payable":false,"stateMutability":"view","type":"function"},{"constant":true,"inputs":[],"name":"testDynamicFixedBytes32","outputs":[{"name":"","type":"bytes32[]"}],"payable":false,"stateMutability":"view","type":"function"}]`))
 	if err != nil {
 		t.Fatal(err)
@@ -321,6 +324,7 @@ func methodMultiReturn(require *require.Assertions) (ABI, []byte, methodMultiOut
 }
 
 func TestMethodMultiReturn(t *testing.T) {
+	t.Parallel()
 	type reversed struct {
 		String string
 		Int    *big.Int
@@ -400,6 +404,7 @@ func TestMethodMultiReturn(t *testing.T) {
 }
 
 func TestMultiReturnWithArray(t *testing.T) {
+	t.Parallel()
 	const definition = `[{"name" : "multi", "type": "function", "outputs": [{"type": "uint64[3]"}, {"type": "uint64"}]}]`
 	abi, err := JSON(strings.NewReader(definition))
 	if err != nil {
@@ -423,6 +428,7 @@ func TestMultiReturnWithArray(t *testing.T) {
 }
 
 func TestMultiReturnWithStringArray(t *testing.T) {
+	t.Parallel()
 	const definition = `[{"name" : "multi", "type": "function", "outputs": [{"name": "","type": "uint256[3]"},{"name": "","type": "address"},{"name": "","type": "string[2]"},{"name": "","type": "bool"}]}]`
 	abi, err := JSON(strings.NewReader(definition))
 	if err != nil {
@@ -453,6 +459,7 @@ func TestMultiReturnWithStringArray(t *testing.T) {
 }
 
 func TestMultiReturnWithStringSlice(t *testing.T) {
+	t.Parallel()
 	const definition = `[{"name" : "multi", "type": "function", "outputs": [{"name": "","type": "string[]"},{"name": "","type": "uint256[]"}]}]`
 	abi, err := JSON(strings.NewReader(definition))
 	if err != nil {
@@ -485,6 +492,7 @@ func TestMultiReturnWithStringSlice(t *testing.T) {
 }
 
 func TestMultiReturnWithDeeplyNestedArray(t *testing.T) {
+	t.Parallel()
 	// Similar to TestMultiReturnWithArray, but with a special case in mind:
 	//  values of nested static arrays count towards the size as well, and any element following
 	//  after such nested array argument should be read with the correct offset,
@@ -525,6 +533,7 @@ func TestMultiReturnWithDeeplyNestedArray(t *testing.T) {
 }
 
 func TestUnmarshal(t *testing.T) {
+	t.Parallel()
 	const definition = `[
 	{ "name" : "int", "type": "function", "outputs": [ { "type": "uint256" } ] },
 	{ "name" : "bool", "type": "function", "outputs": [ { "type": "bool" } ] },
@@ -774,6 +783,7 @@ func TestUnmarshal(t *testing.T) {
 }
 
 func TestUnpackTuple(t *testing.T) {
+	t.Parallel()
 	const simpleTuple = `[{"name":"tuple","type":"function","outputs":[{"type":"tuple","name":"ret","components":[{"type":"int256","name":"a"},{"type":"int256","name":"b"}]}]}]`
 	abi, err := JSON(strings.NewReader(simpleTuple))
 	if err != nil {
@@ -876,6 +886,7 @@ func TestUnpackTuple(t *testing.T) {
 }
 
 func TestOOMMaliciousInput(t *testing.T) {
+	t.Parallel()
 	oomTests := []unpackTest{
 		{
 			def: `[{"type": "uint8[]"}]`,
@@ -946,6 +957,7 @@ func TestOOMMaliciousInput(t *testing.T) {
 }
 
 func TestPackAndUnpackIncompatibleNumber(t *testing.T) {
+	t.Parallel()
 	var encodeABI Arguments
 	uint256Ty, err := NewType("uint256", "", nil)
 	if err != nil {

accounts/accounts.go

@@ -195,7 +195,7 @@ func TextHash(data []byte) []byte {
 //
 // This gives context to the signed message and prevents signing of transactions.
 func TextAndHash(data []byte) ([]byte, string) {
-	msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), string(data))
+	msg := fmt.Sprintf("\x19Ethereum Signed Message:\n%d%s", len(data), data)
 	hasher := sha3.NewLegacyKeccak256()
 	hasher.Write([]byte(msg))
 	return hasher.Sum(nil), msg

accounts/accounts_test.go

@@ -24,6 +24,7 @@ import (
 )
 
 func TestTextHash(t *testing.T) {
+	t.Parallel()
 	hash := TextHash([]byte("Hello Joe"))
 	want := hexutil.MustDecode("0xa080337ae51c4e064c189e113edd0ba391df9206e2f49db658bb32cf2911730b")
 	if !bytes.Equal(hash, want) {

accounts/external/backend.go

@@ -17,6 +17,7 @@
 package external
 
 import (
+	"errors"
 	"fmt"
 	"math/big"
 	"sync"
@@ -98,11 +99,11 @@ func (api *ExternalSigner) Status() (string, error) {
 }
 
 func (api *ExternalSigner) Open(passphrase string) error {
-	return fmt.Errorf("operation not supported on external signers")
+	return errors.New("operation not supported on external signers")
 }
 
 func (api *ExternalSigner) Close() error {
-	return fmt.Errorf("operation not supported on external signers")
+	return errors.New("operation not supported on external signers")
 }
 
 func (api *ExternalSigner) Accounts() []accounts.Account {
@@ -145,7 +146,7 @@ func (api *ExternalSigner) Contains(account accounts.Account) bool {
 }
 
 func (api *ExternalSigner) Derive(path accounts.DerivationPath, pin bool) (accounts.Account, error) {
-	return accounts.Account{}, fmt.Errorf("operation not supported on external signers")
+	return accounts.Account{}, errors.New("operation not supported on external signers")
 }
 
 func (api *ExternalSigner) SelfDerive(bases []accounts.DerivationPath, chain ethereum.ChainStateReader) {
@@ -204,7 +205,7 @@ func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transactio
 		to = &t
 	}
 	args := &apitypes.SendTxArgs{
-		Data:  &data,
+		Input: &data,
 		Nonce: hexutil.Uint64(tx.Nonce()),
 		Value: hexutil.Big(*tx.Value()),
 		Gas:   hexutil.Uint64(tx.Gas()),
@@ -214,7 +215,7 @@ func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transactio
 	switch tx.Type() {
 	case types.LegacyTxType, types.AccessListTxType:
 		args.GasPrice = (*hexutil.Big)(tx.GasPrice())
-	case types.DynamicFeeTxType:
+	case types.DynamicFeeTxType, types.BlobTxType:
 		args.MaxFeePerGas = (*hexutil.Big)(tx.GasFeeCap())
 		args.MaxPriorityFeePerGas = (*hexutil.Big)(tx.GasTipCap())
 	default:
@@ -234,6 +235,17 @@ func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transactio
 		accessList := tx.AccessList()
 		args.AccessList = &accessList
 	}
+	if tx.Type() == types.BlobTxType {
+		args.BlobHashes = tx.BlobHashes()
+		sidecar := tx.BlobTxSidecar()
+		if sidecar == nil {
+			return nil, errors.New("blobs must be present for signing")
+		}
+		args.Blobs = sidecar.Blobs
+		args.Commitments = sidecar.Commitments
+		args.Proofs = sidecar.Proofs
+	}
+
 	var res signTransactionResult
 	if err := api.client.Call(&res, "account_signTransaction", args); err != nil {
 		return nil, err
@@ -242,14 +254,14 @@ func (api *ExternalSigner) SignTx(account accounts.Account, tx *types.Transactio
 }
 
 func (api *ExternalSigner) SignTextWithPassphrase(account accounts.Account, passphrase string, text []byte) ([]byte, error) {
-	return []byte{}, fmt.Errorf("password-operations not supported on external signers")
+	return []byte{}, errors.New("password-operations not supported on external signers")
 }
 
 func (api *ExternalSigner) SignTxWithPassphrase(account accounts.Account, passphrase string, tx *types.Transaction, chainID *big.Int) (*types.Transaction, error) {
-	return nil, fmt.Errorf("password-operations not supported on external signers")
+	return nil, errors.New("password-operations not supported on external signers")
 }
 func (api *ExternalSigner) SignDataWithPassphrase(account accounts.Account, passphrase, mimeType string, data []byte) ([]byte, error) {
-	return nil, fmt.Errorf("password-operations not supported on external signers")
+	return nil, errors.New("password-operations not supported on external signers")
 }
 
 func (api *ExternalSigner) listAccounts() ([]common.Address, error) {

accounts/hd_test.go

@@ -25,6 +25,7 @@ import (
 // Tests that HD derivation paths can be correctly parsed into our internal binary
 // representation.
 func TestHDPathParsing(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		input  string
 		output DerivationPath
@@ -89,6 +90,7 @@ func testDerive(t *testing.T, next func() DerivationPath, expected []string) {
 }
 
 func TestHdPathIteration(t *testing.T) {
+	t.Parallel()
 	testDerive(t, DefaultIterator(DefaultBaseDerivationPath),
 		[]string{
 			"m/44'/60'/0'/0/0", "m/44'/60'/0'/0/1",

accounts/keystore/account_cache.go

@@ -22,6 +22,7 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strings"
 	"sync"
@@ -38,11 +39,10 @@ import (
 // exist yet, the code will attempt to create a watcher at most this often.
 const minReloadInterval = 2 * time.Second
 
-type accountsByURL []accounts.Account
-
-func (s accountsByURL) Len() int           { return len(s) }
-func (s accountsByURL) Less(i, j int) bool { return s[i].URL.Cmp(s[j].URL) < 0 }
-func (s accountsByURL) Swap(i, j int)      { s[i], s[j] = s[j], s[i] }
+// byURL defines the sorting order for accounts.
+func byURL(a, b accounts.Account) int {
+	return a.URL.Cmp(b.URL)
+}
 
 // AmbiguousAddrError is returned when attempting to unlock
 // an address for which more than one file exists.
@@ -67,7 +67,7 @@ type accountCache struct {
 	keydir   string
 	watcher  *watcher
 	mu       sync.Mutex
-	all      accountsByURL
+	all      []accounts.Account
 	byAddr   map[common.Address][]accounts.Account
 	throttle *time.Timer
 	notify   chan struct{}
@@ -194,7 +194,7 @@ func (ac *accountCache) find(a accounts.Account) (accounts.Account, error) {
 	default:
 		err := &AmbiguousAddrError{Addr: a.Address, Matches: make([]accounts.Account, len(matches))}
 		copy(err.Matches, matches)
-		sort.Sort(accountsByURL(err.Matches))
+		slices.SortFunc(err.Matches, byURL)
 		return accounts.Account{}, err
 	}
 }

accounts/keystore/account_cache_test.go

@@ -17,12 +17,13 @@
 package keystore
 
 import (
+	"errors"
 	"fmt"
 	"math/rand"
 	"os"
 	"path/filepath"
 	"reflect"
-	"sort"
+	"slices"
 	"testing"
 	"time"
 
@@ -50,7 +51,7 @@ var (
 	}
 )
 
-// waitWatcherStarts waits up to 1s for the keystore watcher to start.
+// waitWatcherStart waits up to 1s for the keystore watcher to start.
 func waitWatcherStart(ks *KeyStore) bool {
 	// On systems where file watch is not supported, just return "ok".
 	if !ks.cache.watcher.enabled() {
@@ -67,14 +68,14 @@ func waitWatcherStart(ks *KeyStore) bool {
 
 func waitForAccounts(wantAccounts []accounts.Account, ks *KeyStore) error {
 	var list []accounts.Account
-	for t0 := time.Now(); time.Since(t0) < 5*time.Second; time.Sleep(200 * time.Millisecond) {
+	for t0 := time.Now(); time.Since(t0) < 5*time.Second; time.Sleep(100 * time.Millisecond) {
 		list = ks.Accounts()
 		if reflect.DeepEqual(list, wantAccounts) {
 			// ks should have also received change notifications
 			select {
 			case <-ks.changes:
 			default:
-				return fmt.Errorf("wasn't notified of new accounts")
+				return errors.New("wasn't notified of new accounts")
 			}
 			return nil
 		}
@@ -85,7 +86,7 @@ func waitForAccounts(wantAccounts []accounts.Account, ks *KeyStore) error {
 func TestWatchNewFile(t *testing.T) {
 	t.Parallel()
 
-	dir, ks := tmpKeyStore(t, false)
+	dir, ks := tmpKeyStore(t)
 
 	// Ensure the watcher is started before adding any files.
 	ks.Accounts()
@@ -151,6 +152,7 @@ func TestWatchNoDir(t *testing.T) {
 }
 
 func TestCacheInitialReload(t *testing.T) {
+	t.Parallel()
 	cache, _ := newAccountCache(cachetestDir)
 	accounts := cache.accounts()
 	if !reflect.DeepEqual(accounts, cachetestAccounts) {
@@ -159,6 +161,7 @@ func TestCacheInitialReload(t *testing.T) {
 }
 
 func TestCacheAddDeleteOrder(t *testing.T) {
+	t.Parallel()
 	cache, _ := newAccountCache("testdata/no-such-dir")
 	cache.watcher.running = true // prevent unexpected reloads
 
@@ -202,7 +205,7 @@ func TestCacheAddDeleteOrder(t *testing.T) {
 	// Check that the account list is sorted by filename.
 	wantAccounts := make([]accounts.Account, len(accs))
 	copy(wantAccounts, accs)
-	sort.Sort(accountsByURL(wantAccounts))
+	slices.SortFunc(wantAccounts, byURL)
 	list := cache.accounts()
 	if !reflect.DeepEqual(list, wantAccounts) {
 		t.Fatalf("got accounts: %s\nwant %s", spew.Sdump(accs), spew.Sdump(wantAccounts))
@@ -243,6 +246,7 @@ func TestCacheAddDeleteOrder(t *testing.T) {
 }
 
 func TestCacheFind(t *testing.T) {
+	t.Parallel()
 	dir := filepath.Join("testdata", "dir")
 	cache, _ := newAccountCache(dir)
 	cache.watcher.running = true // prevent unexpected reloads
@@ -321,7 +325,8 @@ func TestUpdatedKeyfileContents(t *testing.T) {
 	t.Parallel()
 
 	// Create a temporary keystore to test with
-	dir := filepath.Join(os.TempDir(), fmt.Sprintf("eth-keystore-updatedkeyfilecontents-test-%d-%d", os.Getpid(), rand.Int()))
+	dir := t.TempDir()
+
 	ks := NewKeyStore(dir, LightScryptN, LightScryptP)
 
 	list := ks.Accounts()
@@ -331,9 +336,7 @@ func TestUpdatedKeyfileContents(t *testing.T) {
 	if !waitWatcherStart(ks) {
 		t.Fatal("keystore watcher didn't start in time")
 	}
-	// Create the directory and copy a key file into it.
-	os.MkdirAll(dir, 0700)
-	defer os.RemoveAll(dir)
+	// Copy a key file into it
 	file := filepath.Join(dir, "aaa")
 
 	// Place one of our testfiles in there
@@ -349,7 +352,7 @@ func TestUpdatedKeyfileContents(t *testing.T) {
 		return
 	}
 	// needed so that modTime of `file` is different to its current value after forceCopyFile
-	time.Sleep(time.Second)
+	os.Chtimes(file, time.Now().Add(-time.Second), time.Now().Add(-time.Second))
 
 	// Now replace file contents
 	if err := forceCopyFile(file, cachetestAccounts[1].URL.Path); err != nil {
@@ -365,7 +368,7 @@ func TestUpdatedKeyfileContents(t *testing.T) {
 	}
 
 	// needed so that modTime of `file` is different to its current value after forceCopyFile
-	time.Sleep(time.Second)
+	os.Chtimes(file, time.Now().Add(-time.Second), time.Now().Add(-time.Second))
 
 	// Now replace file contents again
 	if err := forceCopyFile(file, cachetestAccounts[2].URL.Path); err != nil {
@@ -381,7 +384,7 @@ func TestUpdatedKeyfileContents(t *testing.T) {
 	}
 
 	// needed so that modTime of `file` is different to its current value after os.WriteFile
-	time.Sleep(time.Second)
+	os.Chtimes(file, time.Now().Add(-time.Second), time.Now().Add(-time.Second))
 
 	// Now replace file contents with crap
 	if err := os.WriteFile(file, []byte("foo"), 0600); err != nil {

accounts/keystore/keystore.go

@@ -87,15 +87,6 @@ func NewKeyStore(keydir string, scryptN, scryptP int) *KeyStore {
 	return ks
 }
 
-// NewPlaintextKeyStore creates a keystore for the given directory.
-// Deprecated: Use NewKeyStore.
-func NewPlaintextKeyStore(keydir string) *KeyStore {
-	keydir, _ = filepath.Abs(keydir)
-	ks := &KeyStore{storage: &keyStorePlain{keydir}}
-	ks.init(keydir)
-	return ks
-}
-
 func (ks *KeyStore) init(keydir string) {
 	// Lock the mutex since the account cache might call back with events
 	ks.mu.Lock()
@@ -321,11 +312,10 @@ func (ks *KeyStore) Unlock(a accounts.Account, passphrase string) error {
 // Lock removes the private key with the given address from memory.
 func (ks *KeyStore) Lock(addr common.Address) error {
 	ks.mu.Lock()
-	if unl, found := ks.unlocked[addr]; found {
-		ks.mu.Unlock()
+	unl, found := ks.unlocked[addr]
+	ks.mu.Unlock()
+	if found {
 		ks.expire(addr, unl, time.Duration(0)*time.Nanosecond)
-	} else {
-		ks.mu.Unlock()
 	}
 	return nil
 }
@@ -509,7 +499,5 @@ func (ks *KeyStore) isUpdating() bool {
 // zeroKey zeroes a private key in memory.
 func zeroKey(k *ecdsa.PrivateKey) {
 	b := k.D.Bits()
-	for i := range b {
-		b[i] = 0
-	}
+	clear(b)
 }

accounts/keystore/keystore_fuzzing_test.go

@@ -1,4 +1,4 @@
-// Copyright 2016 The go-ethereum Authors
+// Copyright 2023 The go-ethereum Authors
 // This file is part of the go-ethereum library.
 //
 // The go-ethereum library is free software: you can redistribute it and/or modify
@@ -14,19 +14,21 @@
 // You should have received a copy of the GNU Lesser General Public License
 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
 
-//go:build !go1.5
-// +build !go1.5
+package keystore
 
-// no-op implementation of tracing methods for Go < 1.5.
+import (
+	"testing"
+)
 
-package debug
-
-import "errors"
-
-func (*HandlerT) StartGoTrace(string) error {
-	return errors.New("tracing is not supported on Go < 1.5")
-}
-
-func (*HandlerT) StopGoTrace() error {
-	return errors.New("tracing is not supported on Go < 1.5")
+func FuzzPassword(f *testing.F) {
+	f.Fuzz(func(t *testing.T, password string) {
+		ks := NewKeyStore(t.TempDir(), LightScryptN, LightScryptP)
+		a, err := ks.NewAccount(password)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if err := ks.Unlock(a, password); err != nil {
+			t.Fatal(err)
+		}
+	})
 }

accounts/keystore/keystore_test.go

@@ -20,7 +20,7 @@ import (
 	"math/rand"
 	"os"
 	"runtime"
-	"sort"
+	"slices"
 	"strings"
 	"sync"
 	"sync/atomic"
@@ -36,7 +36,8 @@ import (
 var testSigData = make([]byte, 32)
 
 func TestKeyStore(t *testing.T) {
-	dir, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	dir, ks := tmpKeyStore(t)
 
 	a, err := ks.NewAccount("foo")
 	if err != nil {
@@ -70,7 +71,8 @@ func TestKeyStore(t *testing.T) {
 }
 
 func TestSign(t *testing.T) {
-	_, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 
 	pass := "" // not used but required by API
 	a1, err := ks.NewAccount(pass)
@@ -86,7 +88,8 @@ func TestSign(t *testing.T) {
 }
 
 func TestSignWithPassphrase(t *testing.T) {
-	_, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 
 	pass := "passwd"
 	acc, err := ks.NewAccount(pass)
@@ -114,7 +117,7 @@ func TestSignWithPassphrase(t *testing.T) {
 
 func TestTimedUnlock(t *testing.T) {
 	t.Parallel()
-	_, ks := tmpKeyStore(t, true)
+	_, ks := tmpKeyStore(t)
 
 	pass := "foo"
 	a1, err := ks.NewAccount(pass)
@@ -149,7 +152,7 @@ func TestTimedUnlock(t *testing.T) {
 
 func TestOverrideUnlock(t *testing.T) {
 	t.Parallel()
-	_, ks := tmpKeyStore(t, false)
+	_, ks := tmpKeyStore(t)
 
 	pass := "foo"
 	a1, err := ks.NewAccount(pass)
@@ -190,7 +193,7 @@ func TestOverrideUnlock(t *testing.T) {
 // This test should fail under -race if signing races the expiration goroutine.
 func TestSignRace(t *testing.T) {
 	t.Parallel()
-	_, ks := tmpKeyStore(t, false)
+	_, ks := tmpKeyStore(t)
 
 	// Create a test account.
 	a1, err := ks.NewAccount("")
@@ -235,7 +238,7 @@ func waitForKsUpdating(t *testing.T, ks *KeyStore, wantStatus bool, maxTime time
 func TestWalletNotifierLifecycle(t *testing.T) {
 	t.Parallel()
 	// Create a temporary keystore to test with
-	_, ks := tmpKeyStore(t, false)
+	_, ks := tmpKeyStore(t)
 
 	// Ensure that the notification updater is not running yet
 	time.Sleep(250 * time.Millisecond)
@@ -280,7 +283,8 @@ type walletEvent struct {
 // Tests that wallet notifications and correctly fired when accounts are added
 // or deleted from the keystore.
 func TestWalletNotifications(t *testing.T) {
-	_, ks := tmpKeyStore(t, false)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 
 	// Subscribe to the wallet feed and collect events.
 	var (
@@ -339,9 +343,10 @@ func TestWalletNotifications(t *testing.T) {
 	checkEvents(t, wantEvents, events)
 }
 
-// TestImportExport tests the import functionality of a keystore.
+// TestImportECDSA tests the import functionality of a keystore.
 func TestImportECDSA(t *testing.T) {
-	_, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 	key, err := crypto.GenerateKey()
 	if err != nil {
 		t.Fatalf("failed to generate key: %v", key)
@@ -357,9 +362,10 @@ func TestImportECDSA(t *testing.T) {
 	}
 }
 
-// TestImportECDSA tests the import and export functionality of a keystore.
+// TestImportExport tests the import and export functionality of a keystore.
 func TestImportExport(t *testing.T) {
-	_, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 	acc, err := ks.NewAccount("old")
 	if err != nil {
 		t.Fatalf("failed to create account: %v", acc)
@@ -368,7 +374,7 @@ func TestImportExport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed to export account: %v", acc)
 	}
-	_, ks2 := tmpKeyStore(t, true)
+	_, ks2 := tmpKeyStore(t)
 	if _, err = ks2.Import(json, "old", "old"); err == nil {
 		t.Errorf("importing with invalid password succeeded")
 	}
@@ -387,7 +393,8 @@ func TestImportExport(t *testing.T) {
 // TestImportRace tests the keystore on races.
 // This test should fail under -race if importing races.
 func TestImportRace(t *testing.T) {
-	_, ks := tmpKeyStore(t, true)
+	t.Parallel()
+	_, ks := tmpKeyStore(t)
 	acc, err := ks.NewAccount("old")
 	if err != nil {
 		t.Fatalf("failed to create account: %v", acc)
@@ -396,20 +403,20 @@ func TestImportRace(t *testing.T) {
 	if err != nil {
 		t.Fatalf("failed to export account: %v", acc)
 	}
-	_, ks2 := tmpKeyStore(t, true)
-	var atom uint32
+	_, ks2 := tmpKeyStore(t)
+	var atom atomic.Uint32
 	var wg sync.WaitGroup
 	wg.Add(2)
 	for i := 0; i < 2; i++ {
 		go func() {
 			defer wg.Done()
 			if _, err := ks2.Import(json, "new", "new"); err != nil {
-				atomic.AddUint32(&atom, 1)
+				atom.Add(1)
 			}
 		}()
 	}
 	wg.Wait()
-	if atom != 1 {
+	if atom.Load() != 1 {
 		t.Errorf("Import is racy")
 	}
 }
@@ -424,7 +431,7 @@ func checkAccounts(t *testing.T, live map[common.Address]accounts.Account, walle
 	for _, account := range live {
 		liveList = append(liveList, account)
 	}
-	sort.Sort(accountsByURL(liveList))
+	slices.SortFunc(liveList, byURL)
 	for j, wallet := range wallets {
 		if accs := wallet.Accounts(); len(accs) != 1 {
 			t.Errorf("wallet %d: contains invalid number of accounts: have %d, want 1", j, len(accs))
@@ -450,11 +457,7 @@ func checkEvents(t *testing.T, want []walletEvent, have []walletEvent) {
 	}
 }
 
-func tmpKeyStore(t *testing.T, encrypted bool) (string, *KeyStore) {
+func tmpKeyStore(t *testing.T) (string, *KeyStore) {
 	d := t.TempDir()
-	newKs := NewPlaintextKeyStore
-	if encrypted {
-		newKs = func(kd string) *KeyStore { return NewKeyStore(kd, veryLightScryptN, veryLightScryptP) }
-	}
-	return d, newKs(d)
+	return d, NewKeyStore(d, veryLightScryptN, veryLightScryptP)
 }

accounts/keystore/passphrase.go

@@ -136,7 +136,7 @@ func (ks keyStorePassphrase) JoinPath(filename string) string {
 	return filepath.Join(ks.keysDirPath, filename)
 }
 
-// Encryptdata encrypts the data given as 'data' with the password 'auth'.
+// EncryptDataV3 encrypts the data given as 'data' with the password 'auth'.
 func EncryptDataV3(data, auth []byte, scryptN, scryptP int) (CryptoJSON, error) {
 	salt := make([]byte, 32)
 	if _, err := io.ReadFull(rand.Reader, salt); err != nil {
@@ -225,10 +225,13 @@ func DecryptKey(keyjson []byte, auth string) (*Key, error) {
 	if err != nil {
 		return nil, err
 	}
-	key := crypto.ToECDSAUnsafe(keyBytes)
+	key, err := crypto.ToECDSA(keyBytes)
+	if err != nil {
+		return nil, fmt.Errorf("invalid key: %w", err)
+	}
 	id, err := uuid.FromBytes(keyId)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("invalid UUID: %w", err)
 	}
 	return &Key{
 		Id:         id,

accounts/keystore/passphrase_test.go

@@ -30,6 +30,7 @@ const (
 
 // Tests that a json key file can be decrypted and encrypted in multiple rounds.
 func TestKeyEncryptDecrypt(t *testing.T) {
+	t.Parallel()
 	keyjson, err := os.ReadFile("testdata/very-light-scrypt.json")
 	if err != nil {
 		t.Fatal(err)
@@ -54,7 +55,7 @@ func TestKeyEncryptDecrypt(t *testing.T) {
 		// Recrypt with a new password and start over
 		password += "new data appended" // nolint: gosec
 		if keyjson, err = EncryptKey(key, password, veryLightScryptN, veryLightScryptP); err != nil {
-			t.Errorf("test %d: failed to recrypt key %v", i, err)
+			t.Errorf("test %d: failed to re-encrypt key %v", i, err)
 		}
 	}
 }

accounts/keystore/plain_test.go

@@ -40,6 +40,7 @@ func tmpKeyStoreIface(t *testing.T, encrypted bool) (dir string, ks keyStore) {
 }
 
 func TestKeyStorePlain(t *testing.T) {
+	t.Parallel()
 	_, ks := tmpKeyStoreIface(t, false)
 
 	pass := "" // not used but required by API
@@ -60,6 +61,7 @@ func TestKeyStorePlain(t *testing.T) {
 }
 
 func TestKeyStorePassphrase(t *testing.T) {
+	t.Parallel()
 	_, ks := tmpKeyStoreIface(t, true)
 
 	pass := "foo"
@@ -80,6 +82,7 @@ func TestKeyStorePassphrase(t *testing.T) {
 }
 
 func TestKeyStorePassphraseDecryptionFail(t *testing.T) {
+	t.Parallel()
 	_, ks := tmpKeyStoreIface(t, true)
 
 	pass := "foo"
@@ -93,6 +96,7 @@ func TestKeyStorePassphraseDecryptionFail(t *testing.T) {
 }
 
 func TestImportPreSaleKey(t *testing.T) {
+	t.Parallel()
 	dir, ks := tmpKeyStoreIface(t, true)
 
 	// file content of a presale key file generated with:

accounts/keystore/watch.go

@@ -20,6 +20,7 @@
 package keystore
 
 import (
+	"os"
 	"time"
 
 	"github.com/ethereum/go-ethereum/log"
@@ -77,7 +78,9 @@ func (w *watcher) loop() {
 	}
 	defer watcher.Close()
 	if err := watcher.Add(w.ac.keydir); err != nil {
-		logger.Warn("Failed to watch keystore folder", "err", err)
+		if !os.IsNotExist(err) {
+			logger.Warn("Failed to watch keystore folder", "err", err)
+		}
 		return
 	}
 
@@ -122,7 +125,7 @@ func (w *watcher) loop() {
 			if !ok {
 				return
 			}
-			log.Info("Filsystem watcher error", "err", err)
+			log.Info("Filesystem watcher error", "err", err)
 		case <-debounce.C:
 			w.ac.scanAccounts()
 			rescanTriggered = false

accounts/manager.go

@@ -98,6 +98,9 @@ func NewManager(config *Config, backends ...Backend) *Manager {
 
 // Close terminates the account manager's internal notification processes.
 func (am *Manager) Close() error {
+	for _, w := range am.wallets {
+		w.Close()
+	}
 	errc := make(chan error)
 	am.quit <- errc
 	return <-errc

accounts/scwallet/README.md

@@ -8,7 +8,7 @@
 
 ## Preparing the smartcard
 
-  **WARNING: FOILLOWING THESE INSTRUCTIONS WILL DESTROY THE MASTER KEY ON YOUR CARD. ONLY PROCEED IF NO FUNDS ARE ASSOCIATED WITH THESE ACCOUNTS**
+  **WARNING: FOLLOWING THESE INSTRUCTIONS WILL DESTROY THE MASTER KEY ON YOUR CARD. ONLY PROCEED IF NO FUNDS ARE ASSOCIATED WITH THESE ACCOUNTS**
 
   You can use status' [keycard-cli](https://github.com/status-im/keycard-cli) and you should get _at least_ version 2.1.1 of their [smartcard application](https://github.com/status-im/status-keycard/releases/download/2.2.1/keycard_v2.2.1.cap)
 

accounts/scwallet/hub.go

@@ -95,6 +95,7 @@ func (hub *Hub) readPairings() error {
 		}
 		return err
 	}
+	defer pairingFile.Close()
 
 	pairingData, err := io.ReadAll(pairingFile)
 	if err != nil {
@@ -241,7 +242,7 @@ func (hub *Hub) refreshWallets() {
 			card.Disconnect(pcsc.LeaveCard)
 			continue
 		}
-		// Card connected, start tracking in amongs the wallets
+		// Card connected, start tracking among the wallets
 		hub.wallets[reader] = wallet
 		events = append(events, accounts.WalletEvent{Wallet: wallet, Kind: accounts.WalletArrived})
 	}

accounts/scwallet/securechannel.go

@@ -20,10 +20,10 @@ import (
 	"bytes"
 	"crypto/aes"
 	"crypto/cipher"
-	"crypto/elliptic"
 	"crypto/rand"
 	"crypto/sha256"
 	"crypto/sha512"
+	"errors"
 	"fmt"
 
 	"github.com/ethereum/go-ethereum/crypto"
@@ -71,11 +71,11 @@ func NewSecureChannelSession(card *pcsc.Card, keyData []byte) (*SecureChannelSes
 	if err != nil {
 		return nil, fmt.Errorf("could not unmarshal public key from card: %v", err)
 	}
-	secret, _ := key.Curve.ScalarMult(cardPublic.X, cardPublic.Y, key.D.Bytes())
+	secret, _ := crypto.S256().ScalarMult(cardPublic.X, cardPublic.Y, key.D.Bytes())
 	return &SecureChannelSession{
 		card:      card,
 		secret:    secret.Bytes(),
-		publicKey: elliptic.Marshal(crypto.S256(), key.PublicKey.X, key.PublicKey.Y),
+		publicKey: crypto.FromECDSAPub(&key.PublicKey),
 	}, nil
 }
 
@@ -125,7 +125,7 @@ func (s *SecureChannelSession) Pair(pairingPassword []byte) error {
 // Unpair disestablishes an existing pairing.
 func (s *SecureChannelSession) Unpair() error {
 	if s.PairingKey == nil {
-		return fmt.Errorf("cannot unpair: not paired")
+		return errors.New("cannot unpair: not paired")
 	}
 
 	_, err := s.transmitEncrypted(claSCWallet, insUnpair, s.PairingIndex, 0, []byte{})
@@ -141,7 +141,7 @@ func (s *SecureChannelSession) Unpair() error {
 // Open initializes the secure channel.
 func (s *SecureChannelSession) Open() error {
 	if s.iv != nil {
-		return fmt.Errorf("session already opened")
+		return errors.New("session already opened")
 	}
 
 	response, err := s.open()
@@ -215,7 +215,7 @@ func (s *SecureChannelSession) pair(p1 uint8, data []byte) (*responseAPDU, error
 // transmitEncrypted sends an encrypted message, and decrypts and returns the response.
 func (s *SecureChannelSession) transmitEncrypted(cla, ins, p1, p2 byte, data []byte) (*responseAPDU, error) {
 	if s.iv == nil {
-		return nil, fmt.Errorf("channel not open")
+		return nil, errors.New("channel not open")
 	}
 
 	data, err := s.encryptAPDU(data)
@@ -254,7 +254,7 @@ func (s *SecureChannelSession) transmitEncrypted(cla, ins, p1, p2 byte, data []b
 		return nil, err
 	}
 	if !bytes.Equal(s.iv, rmac) {
-		return nil, fmt.Errorf("invalid MAC in response")
+		return nil, errors.New("invalid MAC in response")
 	}
 
 	rapdu := &responseAPDU{}
@@ -319,7 +319,7 @@ func unpad(data []byte, terminator byte) ([]byte, error) {
 			return nil, fmt.Errorf("expected end of padding, got %d", data[len(data)-i])
 		}
 	}
-	return nil, fmt.Errorf("expected end of padding, got 0")
+	return nil, errors.New("expected end of padding, got 0")
 }
 
 // updateIV is an internal method that updates the initialization vector after

accounts/scwallet/wallet.go

@@ -73,6 +73,14 @@ var (
 	DerivationSignatureHash = sha256.Sum256(common.Hash{}.Bytes())
 )
 
+var (
+	// PinRegexp is the regular expression used to validate PIN codes.
+	pinRegexp = regexp.MustCompile(`^[0-9]{6,}$`)
+
+	// PukRegexp is the regular expression used to validate PUK codes.
+	pukRegexp = regexp.MustCompile(`^[0-9]{12,}$`)
+)
+
 // List of APDU command-related constants
 const (
 	claISO7816  = 0
@@ -252,7 +260,7 @@ func (w *Wallet) release() error {
 // with the wallet.
 func (w *Wallet) pair(puk []byte) error {
 	if w.session.paired() {
-		return fmt.Errorf("wallet already paired")
+		return errors.New("wallet already paired")
 	}
 	pairing, err := w.session.pair(puk)
 	if err != nil {
@@ -380,7 +388,7 @@ func (w *Wallet) Open(passphrase string) error {
 	case passphrase == "":
 		return ErrPINUnblockNeeded
 	case status.PinRetryCount > 0:
-		if !regexp.MustCompile(`^[0-9]{6,}$`).MatchString(passphrase) {
+		if !pinRegexp.MatchString(passphrase) {
 			w.log.Error("PIN needs to be at least 6 digits")
 			return ErrPINNeeded
 		}
@@ -388,7 +396,7 @@ func (w *Wallet) Open(passphrase string) error {
 			return err
 		}
 	default:
-		if !regexp.MustCompile(`^[0-9]{12,}$`).MatchString(passphrase) {
+		if !pukRegexp.MatchString(passphrase) {
 			w.log.Error("PUK needs to be at least 12 digits")
 			return ErrPINUnblockNeeded
 		}
@@ -776,16 +784,16 @@ func (w *Wallet) findAccountPath(account accounts.Account) (accounts.DerivationP
 		return nil, fmt.Errorf("scheme %s does not match wallet scheme %s", account.URL.Scheme, w.Hub.scheme)
 	}
 
-	parts := strings.SplitN(account.URL.Path, "/", 2)
-	if len(parts) != 2 {
+	url, path, found := strings.Cut(account.URL.Path, "/")
+	if !found {
 		return nil, fmt.Errorf("invalid URL format: %s", account.URL)
 	}
 
-	if parts[0] != fmt.Sprintf("%x", w.PublicKey[1:3]) {
+	if url != fmt.Sprintf("%x", w.PublicKey[1:3]) {
 		return nil, fmt.Errorf("URL %s is not for this wallet", account.URL)
 	}
 
-	return accounts.ParseDerivationPath(parts[1])
+	return accounts.ParseDerivationPath(path)
 }
 
 // Session represents a secured communication session with the wallet.
@@ -813,7 +821,7 @@ func (s *Session) pair(secret []byte) (smartcardPairing, error) {
 // unpair deletes an existing pairing.
 func (s *Session) unpair() error {
 	if !s.verified {
-		return fmt.Errorf("unpair requires that the PIN be verified")
+		return errors.New("unpair requires that the PIN be verified")
 	}
 	return s.Channel.Unpair()
 }
@@ -907,7 +915,7 @@ func (s *Session) initialize(seed []byte) error {
 		return err
 	}
 	if status == "Online" {
-		return fmt.Errorf("card is already initialized, cowardly refusing to proceed")
+		return errors.New("card is already initialized, cowardly refusing to proceed")
 	}
 
 	s.Wallet.lock.Lock()

accounts/url_test.go

@@ -21,6 +21,7 @@ import (
 )
 
 func TestURLParsing(t *testing.T) {
+	t.Parallel()
 	url, err := parseURL("https://ethereum.org")
 	if err != nil {
 		t.Errorf("unexpected error: %v", err)
@@ -40,6 +41,7 @@ func TestURLParsing(t *testing.T) {
 }
 
 func TestURLString(t *testing.T) {
+	t.Parallel()
 	url := URL{Scheme: "https", Path: "ethereum.org"}
 	if url.String() != "https://ethereum.org" {
 		t.Errorf("expected: %v, got: %v", "https://ethereum.org", url.String())
@@ -52,10 +54,11 @@ func TestURLString(t *testing.T) {
 }
 
 func TestURLMarshalJSON(t *testing.T) {
+	t.Parallel()
 	url := URL{Scheme: "https", Path: "ethereum.org"}
 	json, err := url.MarshalJSON()
 	if err != nil {
-		t.Errorf("unexpcted error: %v", err)
+		t.Errorf("unexpected error: %v", err)
 	}
 	if string(json) != "\"https://ethereum.org\"" {
 		t.Errorf("expected: %v, got: %v", "\"https://ethereum.org\"", string(json))
@@ -63,10 +66,11 @@ func TestURLMarshalJSON(t *testing.T) {
 }
 
 func TestURLUnmarshalJSON(t *testing.T) {
+	t.Parallel()
 	url := &URL{}
 	err := url.UnmarshalJSON([]byte("\"https://ethereum.org\""))
 	if err != nil {
-		t.Errorf("unexpcted error: %v", err)
+		t.Errorf("unexpected error: %v", err)
 	}
 	if url.Scheme != "https" {
 		t.Errorf("expected: %v, got: %v", "https", url.Scheme)
@@ -77,6 +81,7 @@ func TestURLUnmarshalJSON(t *testing.T) {
 }
 
 func TestURLComparison(t *testing.T) {
+	t.Parallel()
 	tests := []struct {
 		urlA   URL
 		urlB   URL

accounts/usbwallet/hub.go

@@ -26,7 +26,7 @@ import (
 	"github.com/ethereum/go-ethereum/accounts"
 	"github.com/ethereum/go-ethereum/event"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/karalabe/usb"
+	"github.com/karalabe/hid"
 )
 
 // LedgerScheme is the protocol scheme prefixing account and wallet URLs.
@@ -63,9 +63,9 @@ type Hub struct {
 	stateLock sync.RWMutex // Protects the internals of the hub from racey access
 
 	// TODO(karalabe): remove if hotplug lands on Windows
-	commsPend int        // Number of operations blocking enumeration
-	commsLock sync.Mutex // Lock protecting the pending counter and enumeration
-	enumFails uint32     // Number of times enumeration has failed
+	commsPend int           // Number of operations blocking enumeration
+	commsLock sync.Mutex    // Lock protecting the pending counter and enumeration
+	enumFails atomic.Uint32 // Number of times enumeration has failed
 }
 
 // NewLedgerHub creates a new hardware wallet manager for Ledger devices.
@@ -109,7 +109,7 @@ func NewTrezorHubWithWebUSB() (*Hub, error) {
 
 // newHub creates a new hardware wallet manager for generic USB devices.
 func newHub(scheme string, vendorID uint16, productIDs []uint16, usageID uint16, endpointID int, makeDriver func(log.Logger) driver) (*Hub, error) {
-	if !usb.Supported() {
+	if !hid.Supported() {
 		return nil, errors.New("unsupported platform")
 	}
 	hub := &Hub{
@@ -151,11 +151,11 @@ func (hub *Hub) refreshWallets() {
 		return
 	}
 	// If USB enumeration is continually failing, don't keep trying indefinitely
-	if atomic.LoadUint32(&hub.enumFails) > 2 {
+	if hub.enumFails.Load() > 2 {
 		return
 	}
 	// Retrieve the current list of USB wallet devices
-	var devices []usb.DeviceInfo
+	var devices []hid.DeviceInfo
 
 	if runtime.GOOS == "linux" {
 		// hidapi on Linux opens the device during enumeration to retrieve some infos,
@@ -170,9 +170,9 @@ func (hub *Hub) refreshWallets() {
 			return
 		}
 	}
-	infos, err := usb.Enumerate(hub.vendorID, 0)
+	infos, err := hid.Enumerate(hub.vendorID, 0)
 	if err != nil {
-		failcount := atomic.AddUint32(&hub.enumFails, 1)
+		failcount := hub.enumFails.Add(1)
 		if runtime.GOOS == "linux" {
 			// See rationale before the enumeration why this is needed and only on Linux.
 			hub.commsLock.Unlock()
@@ -181,7 +181,7 @@ func (hub *Hub) refreshWallets() {
 			"vendor", hub.vendorID, "failcount", failcount, "err", err)
 		return
 	}
-	atomic.StoreUint32(&hub.enumFails, 0)
+	hub.enumFails.Store(0)
 
 	for _, info := range infos {
 		for _, id := range hub.productIDs {

accounts/usbwallet/ledger.go

@@ -16,7 +16,7 @@
 
 // This file contains the implementation for interacting with the Ledger hardware
 // wallets. The wire protocol spec can be found in the Ledger Blue GitHub repo:
-// https://raw.githubusercontent.com/LedgerHQ/blue-app-eth/master/doc/ethapp.asc
+// https://github.com/LedgerHQ/app-ethereum/blob/develop/doc/ethapp.adoc
 
 package usbwallet
 
@@ -279,7 +279,7 @@ func (w *ledgerDriver) ledgerDerive(derivationPath []uint32) (common.Address, er
 	}
 	hexstr := reply[1 : 1+int(reply[0])]
 
-	// Decode the hex sting into an Ethereum address and return
+	// Decode the hex string into an Ethereum address and return
 	var address common.Address
 	if _, err = hex.Decode(address[:], hexstr); err != nil {
 		return common.Address{}, err

accounts/usbwallet/trezor/messages-common.proto

@@ -5,6 +5,8 @@
 syntax = "proto2";
 package hw.trezor.messages.common;
 
+option go_package  = "github.com/ethereum/go-ethereum/accounts/usbwallet/trezor";
+
 /**
  * Response: Success of the previous request
  * @end

accounts/usbwallet/trezor/messages-ethereum.proto

@@ -5,6 +5,8 @@
 syntax = "proto2";
 package hw.trezor.messages.ethereum;
 
+option go_package  = "github.com/ethereum/go-ethereum/accounts/usbwallet/trezor";
+
 // Sugar for easier handling in Java
 option java_package = "com.satoshilabs.trezor.lib.protobuf";
 option java_outer_classname = "TrezorMessageEthereum";

accounts/usbwallet/trezor/messages-management.proto

@@ -5,6 +5,8 @@
 syntax = "proto2";
 package hw.trezor.messages.management;
 
+option go_package  = "github.com/ethereum/go-ethereum/accounts/usbwallet/trezor";
+
 // Sugar for easier handling in Java
 option java_package = "com.satoshilabs.trezor.lib.protobuf";
 option java_outer_classname = "TrezorMessageManagement";

accounts/usbwallet/trezor/messages.proto

@@ -9,10 +9,13 @@ package hw.trezor.messages;
  * Messages for TREZOR communication
  */
 
+option go_package  = "github.com/ethereum/go-ethereum/accounts/usbwallet/trezor";
+
 // Sugar for easier handling in Java
 option java_package = "com.satoshilabs.trezor.lib.protobuf";
 option java_outer_classname = "TrezorMessage";
 
+
 import "google/protobuf/descriptor.proto";
 
 /**

accounts/usbwallet/trezor/trezor.go

@@ -16,7 +16,7 @@
 
 // This file contains the implementation for interacting with the Trezor hardware
 // wallets. The wire protocol spec can be found on the SatoshiLabs website:
-// https://wiki.trezor.io/Developers_guide-Message_Workflows
+// https://docs.trezor.io/trezor-firmware/common/message-workflows.html
 
 // !!! STAHP !!!
 //
@@ -42,7 +42,7 @@
 //   - Grab the latest Go plugin `go get -u github.com/golang/protobuf/protoc-gen-go`
 //   - Vendor in the latest Go plugin `govendor fetch github.com/golang/protobuf/...`
 
-//go:generate protoc -I/usr/local/include:. --go_out=import_path=trezor:. messages.proto messages-common.proto messages-management.proto messages-ethereum.proto
+//go:generate protoc -I/usr/local/include:. --go_out=paths=source_relative:. messages.proto messages-common.proto messages-management.proto messages-ethereum.proto
 
 // Package trezor contains the wire protocol.
 package trezor

accounts/usbwallet/wallet.go

@@ -31,7 +31,7 @@ import (
 	"github.com/ethereum/go-ethereum/core/types"
 	"github.com/ethereum/go-ethereum/crypto"
 	"github.com/ethereum/go-ethereum/log"
-	"github.com/karalabe/usb"
+	"github.com/karalabe/hid"
 )
 
 // Maximum time between wallet health checks to detect USB unplugs.
@@ -79,8 +79,8 @@ type wallet struct {
 	driver driver        // Hardware implementation of the low level device operations
 	url    *accounts.URL // Textual URL uniquely identifying this wallet
 
-	info   usb.DeviceInfo // Known USB device infos about the wallet
-	device usb.Device     // USB device advertising itself as a hardware wallet
+	info   hid.DeviceInfo // Known USB device infos about the wallet
+	device hid.Device     // USB device advertising itself as a hardware wallet
 
 	accounts []accounts.Account                         // List of derive accounts pinned on the hardware wallet
 	paths    map[common.Address]accounts.DerivationPath // Known derivation paths for signing operations
@@ -483,6 +483,10 @@ func (w *wallet) Derive(path accounts.DerivationPath, pin bool) (accounts.Accoun
 	w.stateLock.Lock()
 	defer w.stateLock.Unlock()
 
+	if w.device == nil {
+		return accounts.Account{}, accounts.ErrWalletClosed
+	}
+
 	if _, ok := w.paths[address]; !ok {
 		w.accounts = append(w.accounts, account)
 		w.paths[address] = make(accounts.DerivationPath, len(path))
@@ -624,7 +628,7 @@ func (w *wallet) SignTx(account accounts.Account, tx *types.Transaction, chainID
 	return signed, nil
 }
 
-// SignHashWithPassphrase implements accounts.Wallet, however signing arbitrary
+// SignTextWithPassphrase implements accounts.Wallet, however signing arbitrary
 // data is not supported for Ledger wallets, so this method will always return
 // an error.
 func (w *wallet) SignTextWithPassphrase(account accounts.Account, passphrase string, text []byte) ([]byte, error) {

appveyor.yml

@@ -24,9 +24,10 @@ for:
         - image: Ubuntu
     build_script:
       - go run build/ci.go lint
+      - go run build/ci.go generate -verify
       - go run build/ci.go install -dlgo
     test_script:
-      - go run build/ci.go test -dlgo
+      - go run build/ci.go test -dlgo -short
 
   # linux/386 is disabled.
   - matrix:
@@ -54,4 +55,4 @@ for:
       - go run build/ci.go archive -arch %GETH_ARCH% -type zip -signer WINDOWS_SIGNING_KEY -upload gethstore/builds
       - go run build/ci.go nsis -arch %GETH_ARCH% -signer WINDOWS_SIGNING_KEY -upload gethstore/builds
     test_script:
-      - go run build/ci.go test -dlgo -arch %GETH_ARCH% -cc %GETH_CC%
+      - go run build/ci.go test -dlgo -arch %GETH_ARCH% -cc %GETH_CC% -short

beacon/blsync/block_sync.go

@@ -0,0 +1,163 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package blsync
+
+import (
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/light/sync"
+	"github.com/ethereum/go-ethereum/beacon/params"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/lru"
+	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// beaconBlockSync implements request.Module; it fetches the beacon blocks belonging
+// to the validated and prefetch heads.
+type beaconBlockSync struct {
+	recentBlocks *lru.Cache[common.Hash, *types.BeaconBlock]
+	locked       map[common.Hash]request.ServerAndID
+	serverHeads  map[request.Server]common.Hash
+	headTracker  headTracker
+
+	lastHeadInfo  types.HeadInfo
+	chainHeadFeed event.FeedOf[types.ChainHeadEvent]
+}
+
+type headTracker interface {
+	PrefetchHead() types.HeadInfo
+	ValidatedOptimistic() (types.OptimisticUpdate, bool)
+	ValidatedFinality() (types.FinalityUpdate, bool)
+}
+
+// newBeaconBlockSync returns a new beaconBlockSync.
+func newBeaconBlockSync(headTracker headTracker) *beaconBlockSync {
+	return &beaconBlockSync{
+		headTracker:  headTracker,
+		recentBlocks: lru.NewCache[common.Hash, *types.BeaconBlock](10),
+		locked:       make(map[common.Hash]request.ServerAndID),
+		serverHeads:  make(map[request.Server]common.Hash),
+	}
+}
+
+func (s *beaconBlockSync) SubscribeChainHead(ch chan<- types.ChainHeadEvent) event.Subscription {
+	return s.chainHeadFeed.Subscribe(ch)
+}
+
+// Process implements request.Module.
+func (s *beaconBlockSync) Process(requester request.Requester, events []request.Event) {
+	for _, event := range events {
+		switch event.Type {
+		case request.EvResponse, request.EvFail, request.EvTimeout:
+			sid, req, resp := event.RequestInfo()
+			blockRoot := common.Hash(req.(sync.ReqBeaconBlock))
+			log.Debug("Beacon block event", "type", event.Type.Name, "hash", blockRoot)
+			if resp != nil {
+				s.recentBlocks.Add(blockRoot, resp.(*types.BeaconBlock))
+			}
+			if s.locked[blockRoot] == sid {
+				delete(s.locked, blockRoot)
+			}
+		case sync.EvNewHead:
+			s.serverHeads[event.Server] = event.Data.(types.HeadInfo).BlockRoot
+		case request.EvUnregistered:
+			delete(s.serverHeads, event.Server)
+		}
+	}
+	s.updateEventFeed()
+	// request validated head block if unavailable and not yet requested
+	if vh, ok := s.headTracker.ValidatedOptimistic(); ok {
+		s.tryRequestBlock(requester, vh.Attested.Hash(), false)
+	}
+	// request prefetch head if the given server has announced it
+	if prefetchHead := s.headTracker.PrefetchHead().BlockRoot; prefetchHead != (common.Hash{}) {
+		s.tryRequestBlock(requester, prefetchHead, true)
+	}
+}
+
+func (s *beaconBlockSync) tryRequestBlock(requester request.Requester, blockRoot common.Hash, needSameHead bool) {
+	if _, ok := s.recentBlocks.Get(blockRoot); ok {
+		return
+	}
+	if _, ok := s.locked[blockRoot]; ok {
+		return
+	}
+	for _, server := range requester.CanSendTo() {
+		if needSameHead && (s.serverHeads[server] != blockRoot) {
+			continue
+		}
+		id := requester.Send(server, sync.ReqBeaconBlock(blockRoot))
+		s.locked[blockRoot] = request.ServerAndID{Server: server, ID: id}
+		return
+	}
+}
+
+func blockHeadInfo(block *types.BeaconBlock) types.HeadInfo {
+	if block == nil {
+		return types.HeadInfo{}
+	}
+	return types.HeadInfo{Slot: block.Slot(), BlockRoot: block.Root()}
+}
+
+func (s *beaconBlockSync) updateEventFeed() {
+	optimistic, ok := s.headTracker.ValidatedOptimistic()
+	if !ok {
+		return
+	}
+
+	validatedHead := optimistic.Attested.Hash()
+	headBlock, ok := s.recentBlocks.Get(validatedHead)
+	if !ok {
+		return
+	}
+
+	var finalizedHash common.Hash
+	if finality, ok := s.headTracker.ValidatedFinality(); ok {
+		he := optimistic.Attested.Epoch()
+		fe := finality.Attested.Header.Epoch()
+		switch {
+		case he == fe:
+			finalizedHash = finality.Finalized.PayloadHeader.BlockHash()
+		case he < fe:
+			return
+		case he == fe+1:
+			parent, ok := s.recentBlocks.Get(optimistic.Attested.ParentRoot)
+			if !ok || parent.Slot()/params.EpochLength == fe {
+				return // head is at first slot of next epoch, wait for finality update
+			}
+		}
+	}
+
+	headInfo := blockHeadInfo(headBlock)
+	if headInfo == s.lastHeadInfo {
+		return
+	}
+	s.lastHeadInfo = headInfo
+
+	// new head block and finality info available; extract executable data and send event to feed
+	execBlock, err := headBlock.ExecutionPayload()
+	if err != nil {
+		log.Error("Error extracting execution block from validated beacon block", "error", err)
+		return
+	}
+	s.chainHeadFeed.Send(types.ChainHeadEvent{
+		BeaconHead: optimistic.Attested.Header,
+		Block:      execBlock,
+		Finalized:  finalizedHash,
+	})
+}

beacon/blsync/block_sync_test.go

@@ -0,0 +1,160 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package blsync
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/light/sync"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	zrntcommon "github.com/protolambda/zrnt/eth2/beacon/common"
+	"github.com/protolambda/zrnt/eth2/beacon/deneb"
+)
+
+var (
+	testServer1 = testServer("testServer1")
+	testServer2 = testServer("testServer2")
+
+	testBlock1 = types.NewBeaconBlock(&deneb.BeaconBlock{
+		Slot: 123,
+		Body: deneb.BeaconBlockBody{
+			ExecutionPayload: deneb.ExecutionPayload{
+				BlockNumber: 456,
+				BlockHash:   zrntcommon.Hash32(common.HexToHash("905ac721c4058d9ed40b27b6b9c1bdd10d4333e4f3d9769100bf9dfb80e5d1f6")),
+			},
+		},
+	})
+	testBlock2 = types.NewBeaconBlock(&deneb.BeaconBlock{
+		Slot: 124,
+		Body: deneb.BeaconBlockBody{
+			ExecutionPayload: deneb.ExecutionPayload{
+				BlockNumber: 457,
+				BlockHash:   zrntcommon.Hash32(common.HexToHash("011703f39c664efc1c6cf5f49ca09b595581eec572d4dfddd3d6179a9e63e655")),
+			},
+		},
+	})
+)
+
+type testServer string
+
+func (t testServer) Name() string {
+	return string(t)
+}
+
+func TestBlockSync(t *testing.T) {
+	ht := &testHeadTracker{}
+	blockSync := newBeaconBlockSync(ht)
+	headCh := make(chan types.ChainHeadEvent, 16)
+	blockSync.SubscribeChainHead(headCh)
+	ts := sync.NewTestScheduler(t, blockSync)
+	ts.AddServer(testServer1, 1)
+	ts.AddServer(testServer2, 1)
+
+	expHeadBlock := func(expHead *types.BeaconBlock) {
+		t.Helper()
+		var expNumber, headNumber uint64
+		if expHead != nil {
+			p, _ := expHead.ExecutionPayload()
+			expNumber = p.NumberU64()
+		}
+		select {
+		case event := <-headCh:
+			headNumber = event.Block.NumberU64()
+		default:
+		}
+		if headNumber != expNumber {
+			t.Errorf("Wrong head block, expected block number %d, got %d)", expNumber, headNumber)
+		}
+	}
+
+	// no block requests expected until head tracker knows about a head
+	ts.Run(1)
+	expHeadBlock(nil)
+
+	// set block 1 as prefetch head, announced by server 2
+	head1 := blockHeadInfo(testBlock1)
+	ht.prefetch = head1
+	ts.ServerEvent(sync.EvNewHead, testServer2, head1)
+
+	// expect request to server 2 which has announced the head
+	ts.Run(2, testServer2, sync.ReqBeaconBlock(head1.BlockRoot))
+
+	// valid response
+	ts.RequestEvent(request.EvResponse, ts.Request(2, 1), testBlock1)
+	ts.AddAllowance(testServer2, 1)
+	ts.Run(3)
+	// head block still not expected as the fetched block is not the validated head yet
+	expHeadBlock(nil)
+
+	// set as validated head, expect no further requests but block 1 set as head block
+	ht.validated.Header = testBlock1.Header()
+	ts.Run(4)
+	expHeadBlock(testBlock1)
+
+	// set block 2 as prefetch head, announced by server 1
+	head2 := blockHeadInfo(testBlock2)
+	ht.prefetch = head2
+	ts.ServerEvent(sync.EvNewHead, testServer1, head2)
+	// expect request to server 1
+	ts.Run(5, testServer1, sync.ReqBeaconBlock(head2.BlockRoot))
+
+	// req2 fails, no further requests expected because server 2 has not announced it
+	ts.RequestEvent(request.EvFail, ts.Request(5, 1), nil)
+	ts.Run(6)
+
+	// set as validated head before retrieving block; now it's assumed to be available from server 2 too
+	ht.validated.Header = testBlock2.Header()
+	// expect req2 retry to server 2
+	ts.Run(7, testServer2, sync.ReqBeaconBlock(head2.BlockRoot))
+	// now head block should be unavailable again
+	expHeadBlock(nil)
+
+	// valid response, now head block should be block 2 immediately as it is already validated
+	ts.RequestEvent(request.EvResponse, ts.Request(7, 1), testBlock2)
+	ts.Run(8)
+	expHeadBlock(testBlock2)
+}
+
+type testHeadTracker struct {
+	prefetch  types.HeadInfo
+	validated types.SignedHeader
+}
+
+func (h *testHeadTracker) PrefetchHead() types.HeadInfo {
+	return h.prefetch
+}
+
+func (h *testHeadTracker) ValidatedOptimistic() (types.OptimisticUpdate, bool) {
+	return types.OptimisticUpdate{
+		Attested:      types.HeaderWithExecProof{Header: h.validated.Header},
+		Signature:     h.validated.Signature,
+		SignatureSlot: h.validated.SignatureSlot,
+	}, h.validated.Header != (types.Header{})
+}
+
+// TODO add test case for finality
+func (h *testHeadTracker) ValidatedFinality() (types.FinalityUpdate, bool) {
+	finalized := types.NewExecutionHeader(new(deneb.ExecutionPayloadHeader))
+	return types.FinalityUpdate{
+		Attested:      types.HeaderWithExecProof{Header: h.validated.Header},
+		Finalized:     types.HeaderWithExecProof{PayloadHeader: finalized},
+		Signature:     h.validated.Signature,
+		SignatureSlot: h.validated.SignatureSlot,
+	}, h.validated.Header != (types.Header{})
+}

beacon/blsync/client.go

@@ -0,0 +1,115 @@
+// Copyright 2024 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package blsync
+
+import (
+	"strings"
+
+	"github.com/ethereum/go-ethereum/beacon/light"
+	"github.com/ethereum/go-ethereum/beacon/light/api"
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/light/sync"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/common/mclock"
+	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+	"github.com/ethereum/go-ethereum/event"
+	"github.com/ethereum/go-ethereum/rpc"
+	"github.com/urfave/cli/v2"
+)
+
+type Client struct {
+	urls         []string
+	customHeader map[string]string
+	chainConfig  *lightClientConfig
+	scheduler    *request.Scheduler
+	blockSync    *beaconBlockSync
+	engineRPC    *rpc.Client
+
+	chainHeadSub event.Subscription
+	engineClient *engineClient
+}
+
+func NewClient(ctx *cli.Context) *Client {
+	if !ctx.IsSet(utils.BeaconApiFlag.Name) {
+		utils.Fatalf("Beacon node light client API URL not specified")
+	}
+	var (
+		chainConfig  = makeChainConfig(ctx)
+		customHeader = make(map[string]string)
+	)
+	for _, s := range ctx.StringSlice(utils.BeaconApiHeaderFlag.Name) {
+		kv := strings.Split(s, ":")
+		if len(kv) != 2 {
+			utils.Fatalf("Invalid custom API header entry: %s", s)
+		}
+		customHeader[strings.TrimSpace(kv[0])] = strings.TrimSpace(kv[1])
+	}
+
+	// create data structures
+	var (
+		db             = memorydb.New()
+		threshold      = ctx.Int(utils.BeaconThresholdFlag.Name)
+		committeeChain = light.NewCommitteeChain(db, chainConfig.ChainConfig, threshold, !ctx.Bool(utils.BeaconNoFilterFlag.Name))
+		headTracker    = light.NewHeadTracker(committeeChain, threshold)
+	)
+	headSync := sync.NewHeadSync(headTracker, committeeChain)
+
+	// set up scheduler and sync modules
+	scheduler := request.NewScheduler()
+	checkpointInit := sync.NewCheckpointInit(committeeChain, chainConfig.Checkpoint)
+	forwardSync := sync.NewForwardUpdateSync(committeeChain)
+	beaconBlockSync := newBeaconBlockSync(headTracker)
+	scheduler.RegisterTarget(headTracker)
+	scheduler.RegisterTarget(committeeChain)
+	scheduler.RegisterModule(checkpointInit, "checkpointInit")
+	scheduler.RegisterModule(forwardSync, "forwardSync")
+	scheduler.RegisterModule(headSync, "headSync")
+	scheduler.RegisterModule(beaconBlockSync, "beaconBlockSync")
+
+	return &Client{
+		scheduler:    scheduler,
+		urls:         ctx.StringSlice(utils.BeaconApiFlag.Name),
+		customHeader: customHeader,
+		chainConfig:  &chainConfig,
+		blockSync:    beaconBlockSync,
+	}
+}
+
+func (c *Client) SetEngineRPC(engine *rpc.Client) {
+	c.engineRPC = engine
+}
+
+func (c *Client) Start() error {
+	headCh := make(chan types.ChainHeadEvent, 16)
+	c.chainHeadSub = c.blockSync.SubscribeChainHead(headCh)
+	c.engineClient = startEngineClient(c.chainConfig, c.engineRPC, headCh)
+
+	c.scheduler.Start()
+	for _, url := range c.urls {
+		beaconApi := api.NewBeaconLightApi(url, c.customHeader)
+		c.scheduler.RegisterServer(request.NewServer(api.NewApiServer(beaconApi), &mclock.System{}))
+	}
+	return nil
+}
+
+func (c *Client) Stop() error {
+	c.engineClient.stop()
+	c.chainHeadSub.Unsubscribe()
+	c.scheduler.Stop()
+	return nil
+}

beacon/blsync/config.go

@@ -0,0 +1,129 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package blsync
+
+import (
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/cmd/utils"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/urfave/cli/v2"
+)
+
+// lightClientConfig contains beacon light client configuration
+type lightClientConfig struct {
+	*types.ChainConfig
+	Checkpoint common.Hash
+}
+
+var (
+	MainnetConfig = lightClientConfig{
+		ChainConfig: (&types.ChainConfig{
+			GenesisValidatorsRoot: common.HexToHash("0x4b363db94e286120d76eb905340fdd4e54bfe9f06bf33ff6cf5ad27f511bfe95"),
+			GenesisTime:           1606824023,
+		}).
+			AddFork("GENESIS", 0, []byte{0, 0, 0, 0}).
+			AddFork("ALTAIR", 74240, []byte{1, 0, 0, 0}).
+			AddFork("BELLATRIX", 144896, []byte{2, 0, 0, 0}).
+			AddFork("CAPELLA", 194048, []byte{3, 0, 0, 0}).
+			AddFork("DENEB", 269568, []byte{4, 0, 0, 0}),
+		Checkpoint: common.HexToHash("0x388be41594ec7d6a6894f18c73f3469f07e2c19a803de4755d335817ed8e2e5a"),
+	}
+
+	SepoliaConfig = lightClientConfig{
+		ChainConfig: (&types.ChainConfig{
+			GenesisValidatorsRoot: common.HexToHash("0xd8ea171f3c94aea21ebc42a1ed61052acf3f9209c00e4efbaaddac09ed9b8078"),
+			GenesisTime:           1655733600,
+		}).
+			AddFork("GENESIS", 0, []byte{144, 0, 0, 105}).
+			AddFork("ALTAIR", 50, []byte{144, 0, 0, 112}).
+			AddFork("BELLATRIX", 100, []byte{144, 0, 0, 113}).
+			AddFork("CAPELLA", 56832, []byte{144, 0, 0, 114}).
+			AddFork("DENEB", 132608, []byte{144, 0, 0, 115}),
+		Checkpoint: common.HexToHash("0x1005a6d9175e96bfbce4d35b80f468e9bff0b674e1e861d16e09e10005a58e81"),
+	}
+
+	GoerliConfig = lightClientConfig{
+		ChainConfig: (&types.ChainConfig{
+			GenesisValidatorsRoot: common.HexToHash("0x043db0d9a83813551ee2f33450d23797757d430911a9320530ad8a0eabc43efb"),
+			GenesisTime:           1614588812,
+		}).
+			AddFork("GENESIS", 0, []byte{0, 0, 16, 32}).
+			AddFork("ALTAIR", 36660, []byte{1, 0, 16, 32}).
+			AddFork("BELLATRIX", 112260, []byte{2, 0, 16, 32}).
+			AddFork("CAPELLA", 162304, []byte{3, 0, 16, 32}).
+			AddFork("DENEB", 231680, []byte{4, 0, 16, 32}),
+		Checkpoint: common.HexToHash("0x53a0f4f0a378e2c4ae0a9ee97407eb69d0d737d8d8cd0a5fb1093f42f7b81c49"),
+	}
+)
+
+func makeChainConfig(ctx *cli.Context) lightClientConfig {
+	var config lightClientConfig
+	customConfig := ctx.IsSet(utils.BeaconConfigFlag.Name)
+	utils.CheckExclusive(ctx, utils.MainnetFlag, utils.GoerliFlag, utils.SepoliaFlag, utils.BeaconConfigFlag)
+	switch {
+	case ctx.Bool(utils.MainnetFlag.Name):
+		config = MainnetConfig
+	case ctx.Bool(utils.SepoliaFlag.Name):
+		config = SepoliaConfig
+	case ctx.Bool(utils.GoerliFlag.Name):
+		config = GoerliConfig
+	default:
+		if !customConfig {
+			config = MainnetConfig
+		}
+	}
+	// Genesis root and time should always be specified together with custom chain config
+	if customConfig {
+		if !ctx.IsSet(utils.BeaconGenesisRootFlag.Name) {
+			utils.Fatalf("Custom beacon chain config is specified but genesis root is missing")
+		}
+		if !ctx.IsSet(utils.BeaconGenesisTimeFlag.Name) {
+			utils.Fatalf("Custom beacon chain config is specified but genesis time is missing")
+		}
+		if !ctx.IsSet(utils.BeaconCheckpointFlag.Name) {
+			utils.Fatalf("Custom beacon chain config is specified but checkpoint is missing")
+		}
+		config.ChainConfig = &types.ChainConfig{
+			GenesisTime: ctx.Uint64(utils.BeaconGenesisTimeFlag.Name),
+		}
+		if c, err := hexutil.Decode(ctx.String(utils.BeaconGenesisRootFlag.Name)); err == nil && len(c) <= 32 {
+			copy(config.GenesisValidatorsRoot[:len(c)], c)
+		} else {
+			utils.Fatalf("Invalid hex string", "beacon.genesis.gvroot", ctx.String(utils.BeaconGenesisRootFlag.Name), "error", err)
+		}
+		if err := config.ChainConfig.LoadForks(ctx.String(utils.BeaconConfigFlag.Name)); err != nil {
+			utils.Fatalf("Could not load beacon chain config file", "file name", ctx.String(utils.BeaconConfigFlag.Name), "error", err)
+		}
+	} else {
+		if ctx.IsSet(utils.BeaconGenesisRootFlag.Name) {
+			utils.Fatalf("Genesis root is specified but custom beacon chain config is missing")
+		}
+		if ctx.IsSet(utils.BeaconGenesisTimeFlag.Name) {
+			utils.Fatalf("Genesis time is specified but custom beacon chain config is missing")
+		}
+	}
+	// Checkpoint is required with custom chain config and is optional with pre-defined config
+	if ctx.IsSet(utils.BeaconCheckpointFlag.Name) {
+		if c, err := hexutil.Decode(ctx.String(utils.BeaconCheckpointFlag.Name)); err == nil && len(c) <= 32 {
+			copy(config.Checkpoint[:len(c)], c)
+		} else {
+			utils.Fatalf("Invalid hex string", "beacon.checkpoint", ctx.String(utils.BeaconCheckpointFlag.Name), "error", err)
+		}
+	}
+	return config
+}

beacon/blsync/engineclient.go

@@ -0,0 +1,150 @@
+// Copyright 2024 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package blsync
+
+import (
+	"context"
+	"strings"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/beacon/engine"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	ctypes "github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+type engineClient struct {
+	config     *lightClientConfig
+	rpc        *rpc.Client
+	rootCtx    context.Context
+	cancelRoot context.CancelFunc
+	wg         sync.WaitGroup
+}
+
+func startEngineClient(config *lightClientConfig, rpc *rpc.Client, headCh <-chan types.ChainHeadEvent) *engineClient {
+	ctx, cancel := context.WithCancel(context.Background())
+	ec := &engineClient{
+		config:     config,
+		rpc:        rpc,
+		rootCtx:    ctx,
+		cancelRoot: cancel,
+	}
+	ec.wg.Add(1)
+	go ec.updateLoop(headCh)
+	return ec
+}
+
+func (ec *engineClient) stop() {
+	ec.cancelRoot()
+	ec.wg.Wait()
+}
+
+func (ec *engineClient) updateLoop(headCh <-chan types.ChainHeadEvent) {
+	defer ec.wg.Done()
+
+	for {
+		select {
+		case <-ec.rootCtx.Done():
+			log.Debug("Stopping engine API update loop")
+			return
+
+		case event := <-headCh:
+			if ec.rpc == nil { // dry run, no engine API specified
+				log.Info("New execution block retrieved", "number", event.Block.NumberU64(), "hash", event.Block.Hash(), "finalized", event.Finalized)
+				continue
+			}
+
+			fork := ec.config.ForkAtEpoch(event.BeaconHead.Epoch())
+			forkName := strings.ToLower(fork.Name)
+
+			log.Debug("Calling NewPayload", "number", event.Block.NumberU64(), "hash", event.Block.Hash())
+			if status, err := ec.callNewPayload(forkName, event); err == nil {
+				log.Info("Successful NewPayload", "number", event.Block.NumberU64(), "hash", event.Block.Hash(), "status", status)
+			} else {
+				log.Error("Failed NewPayload", "number", event.Block.NumberU64(), "hash", event.Block.Hash(), "error", err)
+			}
+
+			log.Debug("Calling ForkchoiceUpdated", "head", event.Block.Hash())
+			if status, err := ec.callForkchoiceUpdated(forkName, event); err == nil {
+				log.Info("Successful ForkchoiceUpdated", "head", event.Block.Hash(), "status", status)
+			} else {
+				log.Error("Failed ForkchoiceUpdated", "head", event.Block.Hash(), "error", err)
+			}
+		}
+	}
+}
+
+func (ec *engineClient) callNewPayload(fork string, event types.ChainHeadEvent) (string, error) {
+	execData := engine.BlockToExecutableData(event.Block, nil, nil).ExecutionPayload
+
+	var (
+		method string
+		params = []any{execData}
+	)
+	switch fork {
+	case "deneb":
+		method = "engine_newPayloadV3"
+		parentBeaconRoot := event.BeaconHead.ParentRoot
+		blobHashes := collectBlobHashes(event.Block)
+		params = append(params, blobHashes, parentBeaconRoot)
+	case "capella":
+		method = "engine_newPayloadV2"
+	default:
+		method = "engine_newPayloadV1"
+	}
+
+	ctx, cancel := context.WithTimeout(ec.rootCtx, time.Second*5)
+	defer cancel()
+	var resp engine.PayloadStatusV1
+	err := ec.rpc.CallContext(ctx, &resp, method, params...)
+	return resp.Status, err
+}
+
+func collectBlobHashes(b *ctypes.Block) []common.Hash {
+	list := make([]common.Hash, 0)
+	for _, tx := range b.Transactions() {
+		list = append(list, tx.BlobHashes()...)
+	}
+	return list
+}
+
+func (ec *engineClient) callForkchoiceUpdated(fork string, event types.ChainHeadEvent) (string, error) {
+	update := engine.ForkchoiceStateV1{
+		HeadBlockHash:      event.Block.Hash(),
+		SafeBlockHash:      event.Finalized,
+		FinalizedBlockHash: event.Finalized,
+	}
+
+	var method string
+	switch fork {
+	case "deneb":
+		method = "engine_forkchoiceUpdatedV3"
+	case "capella":
+		method = "engine_forkchoiceUpdatedV2"
+	default:
+		method = "engine_forkchoiceUpdatedV1"
+	}
+
+	ctx, cancel := context.WithTimeout(ec.rootCtx, time.Second*5)
+	defer cancel()
+	var resp engine.ForkChoiceResponse
+	err := ec.rpc.CallContext(ctx, &resp, method, update, nil)
+	return resp.PayloadStatus.Status, err
+}

beacon/engine/errors.go

@@ -80,6 +80,7 @@ var (
 	InvalidPayloadAttributes = &EngineAPIError{code: -38003, msg: "Invalid payload attributes"}
 	TooLargeRequest          = &EngineAPIError{code: -38004, msg: "Too large request"}
 	InvalidParams            = &EngineAPIError{code: -32602, msg: "Invalid parameters"}
+	UnsupportedFork          = &EngineAPIError{code: -38005, msg: "Unsupported fork"}
 
 	STATUS_INVALID         = ForkChoiceResponse{PayloadStatus: PayloadStatusV1{Status: INVALID}, PayloadID: nil}
 	STATUS_SYNCING         = ForkChoiceResponse{PayloadStatus: PayloadStatusV1{Status: SYNCING}, PayloadID: nil}

beacon/engine/gen_blockparams.go

@@ -20,12 +20,14 @@ func (p PayloadAttributes) MarshalJSON() ([]byte, error) {
 		Random                common.Hash         `json:"prevRandao"            gencodec:"required"`
 		SuggestedFeeRecipient common.Address      `json:"suggestedFeeRecipient" gencodec:"required"`
 		Withdrawals           []*types.Withdrawal `json:"withdrawals"`
+		BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 	}
 	var enc PayloadAttributes
 	enc.Timestamp = hexutil.Uint64(p.Timestamp)
 	enc.Random = p.Random
 	enc.SuggestedFeeRecipient = p.SuggestedFeeRecipient
 	enc.Withdrawals = p.Withdrawals
+	enc.BeaconRoot = p.BeaconRoot
 	return json.Marshal(&enc)
 }
 
@@ -36,6 +38,7 @@ func (p *PayloadAttributes) UnmarshalJSON(input []byte) error {
 		Random                *common.Hash        `json:"prevRandao"            gencodec:"required"`
 		SuggestedFeeRecipient *common.Address     `json:"suggestedFeeRecipient" gencodec:"required"`
 		Withdrawals           []*types.Withdrawal `json:"withdrawals"`
+		BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 	}
 	var dec PayloadAttributes
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -56,5 +59,8 @@ func (p *PayloadAttributes) UnmarshalJSON(input []byte) error {
 	if dec.Withdrawals != nil {
 		p.Withdrawals = dec.Withdrawals
 	}
+	if dec.BeaconRoot != nil {
+		p.BeaconRoot = dec.BeaconRoot
+	}
 	return nil
 }

beacon/engine/gen_ed.go

@@ -32,6 +32,8 @@ func (e ExecutableData) MarshalJSON() ([]byte, error) {
 		BlockHash     common.Hash         `json:"blockHash"     gencodec:"required"`
 		Transactions  []hexutil.Bytes     `json:"transactions"  gencodec:"required"`
 		Withdrawals   []*types.Withdrawal `json:"withdrawals"`
+		BlobGasUsed   *hexutil.Uint64     `json:"blobGasUsed"`
+		ExcessBlobGas *hexutil.Uint64     `json:"excessBlobGas"`
 	}
 	var enc ExecutableData
 	enc.ParentHash = e.ParentHash
@@ -54,6 +56,8 @@ func (e ExecutableData) MarshalJSON() ([]byte, error) {
 		}
 	}
 	enc.Withdrawals = e.Withdrawals
+	enc.BlobGasUsed = (*hexutil.Uint64)(e.BlobGasUsed)
+	enc.ExcessBlobGas = (*hexutil.Uint64)(e.ExcessBlobGas)
 	return json.Marshal(&enc)
 }
 
@@ -75,6 +79,8 @@ func (e *ExecutableData) UnmarshalJSON(input []byte) error {
 		BlockHash     *common.Hash        `json:"blockHash"     gencodec:"required"`
 		Transactions  []hexutil.Bytes     `json:"transactions"  gencodec:"required"`
 		Withdrawals   []*types.Withdrawal `json:"withdrawals"`
+		BlobGasUsed   *hexutil.Uint64     `json:"blobGasUsed"`
+		ExcessBlobGas *hexutil.Uint64     `json:"excessBlobGas"`
 	}
 	var dec ExecutableData
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -142,5 +148,11 @@ func (e *ExecutableData) UnmarshalJSON(input []byte) error {
 	if dec.Withdrawals != nil {
 		e.Withdrawals = dec.Withdrawals
 	}
+	if dec.BlobGasUsed != nil {
+		e.BlobGasUsed = (*uint64)(dec.BlobGasUsed)
+	}
+	if dec.ExcessBlobGas != nil {
+		e.ExcessBlobGas = (*uint64)(dec.ExcessBlobGas)
+	}
 	return nil
 }

beacon/engine/gen_epe.go

@@ -17,10 +17,14 @@ func (e ExecutionPayloadEnvelope) MarshalJSON() ([]byte, error) {
 	type ExecutionPayloadEnvelope struct {
 		ExecutionPayload *ExecutableData `json:"executionPayload"  gencodec:"required"`
 		BlockValue       *hexutil.Big    `json:"blockValue"  gencodec:"required"`
+		BlobsBundle      *BlobsBundleV1  `json:"blobsBundle"`
+		Override         bool            `json:"shouldOverrideBuilder"`
 	}
 	var enc ExecutionPayloadEnvelope
 	enc.ExecutionPayload = e.ExecutionPayload
 	enc.BlockValue = (*hexutil.Big)(e.BlockValue)
+	enc.BlobsBundle = e.BlobsBundle
+	enc.Override = e.Override
 	return json.Marshal(&enc)
 }
 
@@ -29,6 +33,8 @@ func (e *ExecutionPayloadEnvelope) UnmarshalJSON(input []byte) error {
 	type ExecutionPayloadEnvelope struct {
 		ExecutionPayload *ExecutableData `json:"executionPayload"  gencodec:"required"`
 		BlockValue       *hexutil.Big    `json:"blockValue"  gencodec:"required"`
+		BlobsBundle      *BlobsBundleV1  `json:"blobsBundle"`
+		Override         *bool           `json:"shouldOverrideBuilder"`
 	}
 	var dec ExecutionPayloadEnvelope
 	if err := json.Unmarshal(input, &dec); err != nil {
@@ -42,5 +48,11 @@ func (e *ExecutionPayloadEnvelope) UnmarshalJSON(input []byte) error {
 		return errors.New("missing required field 'blockValue' for ExecutionPayloadEnvelope")
 	}
 	e.BlockValue = (*big.Int)(dec.BlockValue)
+	if dec.BlobsBundle != nil {
+		e.BlobsBundle = dec.BlobsBundle
+	}
+	if dec.Override != nil {
+		e.Override = *dec.Override
+	}
 	return nil
 }

beacon/engine/types.go

@@ -19,6 +19,7 @@ package engine
 import (
 	"fmt"
 	"math/big"
+	"slices"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/common/hexutil"
@@ -26,6 +27,16 @@ import (
 	"github.com/ethereum/go-ethereum/trie"
 )
 
+// PayloadVersion denotes the version of PayloadAttributes used to request the
+// building of the payload to commence.
+type PayloadVersion byte
+
+var (
+	PayloadV1 PayloadVersion = 0x1
+	PayloadV2 PayloadVersion = 0x2
+	PayloadV3 PayloadVersion = 0x3
+)
+
 //go:generate go run github.com/fjl/gencodec -type PayloadAttributes -field-override payloadAttributesMarshaling -out gen_blockparams.go
 
 // PayloadAttributes describes the environment context in which a block should
@@ -35,6 +46,7 @@ type PayloadAttributes struct {
 	Random                common.Hash         `json:"prevRandao"            gencodec:"required"`
 	SuggestedFeeRecipient common.Address      `json:"suggestedFeeRecipient" gencodec:"required"`
 	Withdrawals           []*types.Withdrawal `json:"withdrawals"`
+	BeaconRoot            *common.Hash        `json:"parentBeaconBlockRoot"`
 }
 
 // JSON type overrides for PayloadAttributes.
@@ -61,6 +73,8 @@ type ExecutableData struct {
 	BlockHash     common.Hash         `json:"blockHash"     gencodec:"required"`
 	Transactions  [][]byte            `json:"transactions"  gencodec:"required"`
 	Withdrawals   []*types.Withdrawal `json:"withdrawals"`
+	BlobGasUsed   *uint64             `json:"blobGasUsed"`
+	ExcessBlobGas *uint64             `json:"excessBlobGas"`
 }
 
 // JSON type overrides for executableData.
@@ -73,6 +87,8 @@ type executableDataMarshaling struct {
 	ExtraData     hexutil.Bytes
 	LogsBloom     hexutil.Bytes
 	Transactions  []hexutil.Bytes
+	BlobGasUsed   *hexutil.Uint64
+	ExcessBlobGas *hexutil.Uint64
 }
 
 //go:generate go run github.com/fjl/gencodec -type ExecutionPayloadEnvelope -field-override executionPayloadEnvelopeMarshaling -out gen_epe.go
@@ -80,6 +96,14 @@ type executableDataMarshaling struct {
 type ExecutionPayloadEnvelope struct {
 	ExecutionPayload *ExecutableData `json:"executionPayload"  gencodec:"required"`
 	BlockValue       *big.Int        `json:"blockValue"  gencodec:"required"`
+	BlobsBundle      *BlobsBundleV1  `json:"blobsBundle"`
+	Override         bool            `json:"shouldOverrideBuilder"`
+}
+
+type BlobsBundleV1 struct {
+	Commitments []hexutil.Bytes `json:"commitments"`
+	Proofs      []hexutil.Bytes `json:"proofs"`
+	Blobs       []hexutil.Bytes `json:"blobs"`
 }
 
 // JSON type overrides for ExecutionPayloadEnvelope.
@@ -102,6 +126,16 @@ type TransitionConfigurationV1 struct {
 // PayloadID is an identifier of the payload build process
 type PayloadID [8]byte
 
+// Version returns the payload version associated with the identifier.
+func (b PayloadID) Version() PayloadVersion {
+	return PayloadVersion(b[0])
+}
+
+// Is returns whether the identifier matches any of provided payload versions.
+func (b PayloadID) Is(versions ...PayloadVersion) bool {
+	return slices.Contains(versions, b.Version())
+}
+
 func (b PayloadID) String() string {
 	return hexutil.Encode(b[:])
 }
@@ -152,14 +186,15 @@ func decodeTransactions(enc [][]byte) ([]*types.Transaction, error) {
 // ExecutableDataToBlock constructs a block from executable data.
 // It verifies that the following fields:
 //
-//	len(extraData) <= 32
-//	uncleHash = emptyUncleHash
-//	difficulty = 0
+//		len(extraData) <= 32
+//		uncleHash = emptyUncleHash
+//		difficulty = 0
+//	 	if versionedHashes != nil, versionedHashes match to blob transactions
 //
 // and that the blockhash of the constructed block matches the parameters. Nil
 // Withdrawals value will propagate through the returned block. Empty
 // Withdrawals value must be passed via non-nil, length 0 value in params.
-func ExecutableDataToBlock(params ExecutableData) (*types.Block, error) {
+func ExecutableDataToBlock(params ExecutableData, versionedHashes []common.Hash, beaconRoot *common.Hash) (*types.Block, error) {
 	txs, err := decodeTransactions(params.Transactions)
 	if err != nil {
 		return nil, err
@@ -174,6 +209,18 @@ func ExecutableDataToBlock(params ExecutableData) (*types.Block, error) {
 	if params.BaseFeePerGas != nil && (params.BaseFeePerGas.Sign() == -1 || params.BaseFeePerGas.BitLen() > 256) {
 		return nil, fmt.Errorf("invalid baseFeePerGas: %v", params.BaseFeePerGas)
 	}
+	var blobHashes = make([]common.Hash, 0, len(txs))
+	for _, tx := range txs {
+		blobHashes = append(blobHashes, tx.BlobHashes()...)
+	}
+	if len(blobHashes) != len(versionedHashes) {
+		return nil, fmt.Errorf("invalid number of versionedHashes: %v blobHashes: %v", versionedHashes, blobHashes)
+	}
+	for i := 0; i < len(blobHashes); i++ {
+		if blobHashes[i] != versionedHashes[i] {
+			return nil, fmt.Errorf("invalid versionedHash at %v: %v blobHashes: %v", i, versionedHashes, blobHashes)
+		}
+	}
 	// Only set withdrawalsRoot if it is non-nil. This allows CLs to use
 	// ExecutableData before withdrawals are enabled by marshaling
 	// Withdrawals as the json null value.
@@ -183,24 +230,27 @@ func ExecutableDataToBlock(params ExecutableData) (*types.Block, error) {
 		withdrawalsRoot = &h
 	}
 	header := &types.Header{
-		ParentHash:      params.ParentHash,
-		UncleHash:       types.EmptyUncleHash,
-		Coinbase:        params.FeeRecipient,
-		Root:            params.StateRoot,
-		TxHash:          types.DeriveSha(types.Transactions(txs), trie.NewStackTrie(nil)),
-		ReceiptHash:     params.ReceiptsRoot,
-		Bloom:           types.BytesToBloom(params.LogsBloom),
-		Difficulty:      common.Big0,
-		Number:          new(big.Int).SetUint64(params.Number),
-		GasLimit:        params.GasLimit,
-		GasUsed:         params.GasUsed,
-		Time:            params.Timestamp,
-		BaseFee:         params.BaseFeePerGas,
-		Extra:           params.ExtraData,
-		MixDigest:       params.Random,
-		WithdrawalsHash: withdrawalsRoot,
+		ParentHash:       params.ParentHash,
+		UncleHash:        types.EmptyUncleHash,
+		Coinbase:         params.FeeRecipient,
+		Root:             params.StateRoot,
+		TxHash:           types.DeriveSha(types.Transactions(txs), trie.NewStackTrie(nil)),
+		ReceiptHash:      params.ReceiptsRoot,
+		Bloom:            types.BytesToBloom(params.LogsBloom),
+		Difficulty:       common.Big0,
+		Number:           new(big.Int).SetUint64(params.Number),
+		GasLimit:         params.GasLimit,
+		GasUsed:          params.GasUsed,
+		Time:             params.Timestamp,
+		BaseFee:          params.BaseFeePerGas,
+		Extra:            params.ExtraData,
+		MixDigest:        params.Random,
+		WithdrawalsHash:  withdrawalsRoot,
+		ExcessBlobGas:    params.ExcessBlobGas,
+		BlobGasUsed:      params.BlobGasUsed,
+		ParentBeaconRoot: beaconRoot,
 	}
-	block := types.NewBlockWithHeader(header).WithBody(txs, nil /* uncles */).WithWithdrawals(params.Withdrawals)
+	block := types.NewBlockWithHeader(header).WithBody(types.Body{Transactions: txs, Uncles: nil, Withdrawals: params.Withdrawals})
 	if block.Hash() != params.BlockHash {
 		return nil, fmt.Errorf("blockhash mismatch, want %x, got %x", params.BlockHash, block.Hash())
 	}
@@ -209,7 +259,7 @@ func ExecutableDataToBlock(params ExecutableData) (*types.Block, error) {
 
 // BlockToExecutableData constructs the ExecutableData structure by filling the
 // fields from the given block. It assumes the given block is post-merge block.
-func BlockToExecutableData(block *types.Block, fees *big.Int) *ExecutionPayloadEnvelope {
+func BlockToExecutableData(block *types.Block, fees *big.Int, sidecars []*types.BlobTxSidecar) *ExecutionPayloadEnvelope {
 	data := &ExecutableData{
 		BlockHash:     block.Hash(),
 		ParentHash:    block.ParentHash(),
@@ -226,8 +276,22 @@ func BlockToExecutableData(block *types.Block, fees *big.Int) *ExecutionPayloadE
 		Random:        block.MixDigest(),
 		ExtraData:     block.Extra(),
 		Withdrawals:   block.Withdrawals(),
+		BlobGasUsed:   block.BlobGasUsed(),
+		ExcessBlobGas: block.ExcessBlobGas(),
 	}
-	return &ExecutionPayloadEnvelope{ExecutionPayload: data, BlockValue: fees}
+	bundle := BlobsBundleV1{
+		Commitments: make([]hexutil.Bytes, 0),
+		Blobs:       make([]hexutil.Bytes, 0),
+		Proofs:      make([]hexutil.Bytes, 0),
+	}
+	for _, sidecar := range sidecars {
+		for j := range sidecar.Blobs {
+			bundle.Blobs = append(bundle.Blobs, hexutil.Bytes(sidecar.Blobs[j][:]))
+			bundle.Commitments = append(bundle.Commitments, hexutil.Bytes(sidecar.Commitments[j][:]))
+			bundle.Proofs = append(bundle.Proofs, hexutil.Bytes(sidecar.Proofs[j][:]))
+		}
+	}
+	return &ExecutionPayloadEnvelope{ExecutionPayload: data, BlockValue: fees, BlobsBundle: &bundle, Override: false}
 }
 
 // ExecutionPayloadBodyV1 is used in the response to GetPayloadBodiesByHashV1 and GetPayloadBodiesByRangeV1
@@ -235,3 +299,21 @@ type ExecutionPayloadBodyV1 struct {
 	TransactionData []hexutil.Bytes     `json:"transactions"`
 	Withdrawals     []*types.Withdrawal `json:"withdrawals"`
 }
+
+// Client identifiers to support ClientVersionV1.
+const (
+	ClientCode = "GE"
+	ClientName = "go-ethereum"
+)
+
+// ClientVersionV1 contains information which identifies a client implementation.
+type ClientVersionV1 struct {
+	Code    string `json:"code"`
+	Name    string `json:"name"`
+	Version string `json:"version"`
+	Commit  string `json:"commit"`
+}
+
+func (v *ClientVersionV1) String() string {
+	return fmt.Sprintf("%s-%s-%s-%s", v.Code, v.Name, v.Version, v.Commit)
+}

beacon/light/api/api_server.go

@@ -0,0 +1,114 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"reflect"
+
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/light/sync"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// ApiServer is a wrapper around BeaconLightApi that implements request.requestServer.
+type ApiServer struct {
+	api           *BeaconLightApi
+	eventCallback func(event request.Event)
+	unsubscribe   func()
+}
+
+// NewApiServer creates a new ApiServer.
+func NewApiServer(api *BeaconLightApi) *ApiServer {
+	return &ApiServer{api: api}
+}
+
+// Subscribe implements request.requestServer.
+func (s *ApiServer) Subscribe(eventCallback func(event request.Event)) {
+	s.eventCallback = eventCallback
+	listener := HeadEventListener{
+		OnNewHead: func(slot uint64, blockRoot common.Hash) {
+			log.Debug("New head received", "slot", slot, "blockRoot", blockRoot)
+			eventCallback(request.Event{Type: sync.EvNewHead, Data: types.HeadInfo{Slot: slot, BlockRoot: blockRoot}})
+		},
+		OnOptimistic: func(update types.OptimisticUpdate) {
+			log.Debug("New optimistic update received", "slot", update.Attested.Slot, "blockRoot", update.Attested.Hash(), "signerCount", update.Signature.SignerCount())
+			eventCallback(request.Event{Type: sync.EvNewOptimisticUpdate, Data: update})
+		},
+		OnFinality: func(update types.FinalityUpdate) {
+			log.Debug("New finality update received", "slot", update.Attested.Slot, "blockRoot", update.Attested.Hash(), "signerCount", update.Signature.SignerCount())
+			eventCallback(request.Event{Type: sync.EvNewFinalityUpdate, Data: update})
+		},
+		OnError: func(err error) {
+			log.Warn("Head event stream error", "err", err)
+		},
+	}
+	s.unsubscribe = s.api.StartHeadListener(listener)
+}
+
+// SendRequest implements request.requestServer.
+func (s *ApiServer) SendRequest(id request.ID, req request.Request) {
+	go func() {
+		var resp request.Response
+		var err error
+		switch data := req.(type) {
+		case sync.ReqUpdates:
+			log.Debug("Beacon API: requesting light client update", "reqid", id, "period", data.FirstPeriod, "count", data.Count)
+			var r sync.RespUpdates
+			r.Updates, r.Committees, err = s.api.GetBestUpdatesAndCommittees(data.FirstPeriod, data.Count)
+			resp = r
+		case sync.ReqHeader:
+			var r sync.RespHeader
+			log.Debug("Beacon API: requesting header", "reqid", id, "hash", common.Hash(data))
+			r.Header, r.Canonical, r.Finalized, err = s.api.GetHeader(common.Hash(data))
+			resp = r
+		case sync.ReqCheckpointData:
+			log.Debug("Beacon API: requesting checkpoint data", "reqid", id, "hash", common.Hash(data))
+			resp, err = s.api.GetCheckpointData(common.Hash(data))
+		case sync.ReqBeaconBlock:
+			log.Debug("Beacon API: requesting block", "reqid", id, "hash", common.Hash(data))
+			resp, err = s.api.GetBeaconBlock(common.Hash(data))
+		case sync.ReqFinality:
+			log.Debug("Beacon API: requesting finality update")
+			resp, err = s.api.GetFinalityUpdate()
+		default:
+		}
+
+		if err != nil {
+			log.Warn("Beacon API request failed", "type", reflect.TypeOf(req), "reqid", id, "err", err)
+			s.eventCallback(request.Event{Type: request.EvFail, Data: request.RequestResponse{ID: id, Request: req}})
+		} else {
+			log.Debug("Beacon API request answered", "type", reflect.TypeOf(req), "reqid", id)
+			s.eventCallback(request.Event{Type: request.EvResponse, Data: request.RequestResponse{ID: id, Request: req, Response: resp}})
+		}
+	}()
+}
+
+// Unsubscribe implements request.requestServer.
+// Note: Unsubscribe should not be called concurrently with Subscribe.
+func (s *ApiServer) Unsubscribe() {
+	if s.unsubscribe != nil {
+		s.unsubscribe()
+		s.unsubscribe = nil
+	}
+}
+
+// Name implements request.Server
+func (s *ApiServer) Name() string {
+	return s.api.url
+}

beacon/light/api/light_api.go

@@ -0,0 +1,578 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more detaiapi.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package api
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"sync"
+	"time"
+
+	"github.com/donovanhide/eventsource"
+	"github.com/ethereum/go-ethereum/beacon/merkle"
+	"github.com/ethereum/go-ethereum/beacon/params"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+var (
+	ErrNotFound = errors.New("404 Not Found")
+	ErrInternal = errors.New("500 Internal Server Error")
+)
+
+type CommitteeUpdate struct {
+	Version           string
+	Update            types.LightClientUpdate
+	NextSyncCommittee types.SerializedSyncCommittee
+}
+
+// See data structure definition here:
+// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/sync-protocol.md#lightclientupdate
+type committeeUpdateJson struct {
+	Version string              `json:"version"`
+	Data    committeeUpdateData `json:"data"`
+}
+
+type committeeUpdateData struct {
+	Header                  jsonBeaconHeader              `json:"attested_header"`
+	NextSyncCommittee       types.SerializedSyncCommittee `json:"next_sync_committee"`
+	NextSyncCommitteeBranch merkle.Values                 `json:"next_sync_committee_branch"`
+	FinalizedHeader         *jsonBeaconHeader             `json:"finalized_header,omitempty"`
+	FinalityBranch          merkle.Values                 `json:"finality_branch,omitempty"`
+	SyncAggregate           types.SyncAggregate           `json:"sync_aggregate"`
+	SignatureSlot           common.Decimal                `json:"signature_slot"`
+}
+
+type jsonBeaconHeader struct {
+	Beacon types.Header `json:"beacon"`
+}
+
+type jsonHeaderWithExecProof struct {
+	Beacon          types.Header    `json:"beacon"`
+	Execution       json.RawMessage `json:"execution"`
+	ExecutionBranch merkle.Values   `json:"execution_branch"`
+}
+
+// UnmarshalJSON unmarshals from JSON.
+func (u *CommitteeUpdate) UnmarshalJSON(input []byte) error {
+	var dec committeeUpdateJson
+	if err := json.Unmarshal(input, &dec); err != nil {
+		return err
+	}
+	u.Version = dec.Version
+	u.NextSyncCommittee = dec.Data.NextSyncCommittee
+	u.Update = types.LightClientUpdate{
+		AttestedHeader: types.SignedHeader{
+			Header:        dec.Data.Header.Beacon,
+			Signature:     dec.Data.SyncAggregate,
+			SignatureSlot: uint64(dec.Data.SignatureSlot),
+		},
+		NextSyncCommitteeRoot:   u.NextSyncCommittee.Root(),
+		NextSyncCommitteeBranch: dec.Data.NextSyncCommitteeBranch,
+		FinalityBranch:          dec.Data.FinalityBranch,
+	}
+	if dec.Data.FinalizedHeader != nil {
+		u.Update.FinalizedHeader = &dec.Data.FinalizedHeader.Beacon
+	}
+	return nil
+}
+
+// fetcher is an interface useful for debug-harnessing the http api.
+type fetcher interface {
+	Do(req *http.Request) (*http.Response, error)
+}
+
+// BeaconLightApi requests light client information from a beacon node REST API.
+// Note: all required API endpoints are currently only implemented by Lodestar.
+type BeaconLightApi struct {
+	url           string
+	client        fetcher
+	customHeaders map[string]string
+}
+
+func NewBeaconLightApi(url string, customHeaders map[string]string) *BeaconLightApi {
+	return &BeaconLightApi{
+		url: url,
+		client: &http.Client{
+			Timeout: time.Second * 10,
+		},
+		customHeaders: customHeaders,
+	}
+}
+
+func (api *BeaconLightApi) httpGet(path string) ([]byte, error) {
+	req, err := http.NewRequest("GET", api.url+path, nil)
+	if err != nil {
+		return nil, err
+	}
+	for k, v := range api.customHeaders {
+		req.Header.Set(k, v)
+	}
+	resp, err := api.client.Do(req)
+	if err != nil {
+		return nil, err
+	}
+	defer resp.Body.Close()
+	switch resp.StatusCode {
+	case 200:
+		return io.ReadAll(resp.Body)
+	case 404:
+		return nil, ErrNotFound
+	case 500:
+		return nil, ErrInternal
+	default:
+		return nil, fmt.Errorf("unexpected error from API endpoint \"%s\": status code %d", path, resp.StatusCode)
+	}
+}
+
+func (api *BeaconLightApi) httpGetf(format string, params ...any) ([]byte, error) {
+	return api.httpGet(fmt.Sprintf(format, params...))
+}
+
+// GetBestUpdatesAndCommittees fetches and validates LightClientUpdate for given
+// period and full serialized committee for the next period (committee root hash
+// equals update.NextSyncCommitteeRoot).
+// Note that the results are validated but the update signature should be verified
+// by the caller as its validity depends on the update chain.
+func (api *BeaconLightApi) GetBestUpdatesAndCommittees(firstPeriod, count uint64) ([]*types.LightClientUpdate, []*types.SerializedSyncCommittee, error) {
+	resp, err := api.httpGetf("/eth/v1/beacon/light_client/updates?start_period=%d&count=%d", firstPeriod, count)
+	if err != nil {
+		return nil, nil, err
+	}
+
+	var data []CommitteeUpdate
+	if err := json.Unmarshal(resp, &data); err != nil {
+		return nil, nil, err
+	}
+	if len(data) != int(count) {
+		return nil, nil, errors.New("invalid number of committee updates")
+	}
+	updates := make([]*types.LightClientUpdate, int(count))
+	committees := make([]*types.SerializedSyncCommittee, int(count))
+	for i, d := range data {
+		if d.Update.AttestedHeader.Header.SyncPeriod() != firstPeriod+uint64(i) {
+			return nil, nil, errors.New("wrong committee update header period")
+		}
+		if err := d.Update.Validate(); err != nil {
+			return nil, nil, err
+		}
+		if d.NextSyncCommittee.Root() != d.Update.NextSyncCommitteeRoot {
+			return nil, nil, errors.New("wrong sync committee root")
+		}
+		updates[i], committees[i] = new(types.LightClientUpdate), new(types.SerializedSyncCommittee)
+		*updates[i], *committees[i] = d.Update, d.NextSyncCommittee
+	}
+	return updates, committees, nil
+}
+
+// GetOptimisticUpdate fetches the latest available optimistic update.
+// Note that the signature should be verified by the caller as its validity
+// depends on the update chain.
+//
+// See data structure definition here:
+// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/sync-protocol.md#lightclientoptimisticupdate
+func (api *BeaconLightApi) GetOptimisticUpdate() (types.OptimisticUpdate, error) {
+	resp, err := api.httpGet("/eth/v1/beacon/light_client/optimistic_update")
+	if err != nil {
+		return types.OptimisticUpdate{}, err
+	}
+	return decodeOptimisticUpdate(resp)
+}
+
+func decodeOptimisticUpdate(enc []byte) (types.OptimisticUpdate, error) {
+	var data struct {
+		Version string
+		Data    struct {
+			Attested      jsonHeaderWithExecProof `json:"attested_header"`
+			Aggregate     types.SyncAggregate     `json:"sync_aggregate"`
+			SignatureSlot common.Decimal          `json:"signature_slot"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(enc, &data); err != nil {
+		return types.OptimisticUpdate{}, err
+	}
+	// Decode the execution payload headers.
+	attestedExecHeader, err := types.ExecutionHeaderFromJSON(data.Version, data.Data.Attested.Execution)
+	if err != nil {
+		return types.OptimisticUpdate{}, fmt.Errorf("invalid attested header: %v", err)
+	}
+	if data.Data.Attested.Beacon.StateRoot == (common.Hash{}) {
+		// workaround for different event encoding format in Lodestar
+		if err := json.Unmarshal(enc, &data.Data); err != nil {
+			return types.OptimisticUpdate{}, err
+		}
+	}
+
+	if len(data.Data.Aggregate.Signers) != params.SyncCommitteeBitmaskSize {
+		return types.OptimisticUpdate{}, errors.New("invalid sync_committee_bits length")
+	}
+	if len(data.Data.Aggregate.Signature) != params.BLSSignatureSize {
+		return types.OptimisticUpdate{}, errors.New("invalid sync_committee_signature length")
+	}
+	return types.OptimisticUpdate{
+		Attested: types.HeaderWithExecProof{
+			Header:        data.Data.Attested.Beacon,
+			PayloadHeader: attestedExecHeader,
+			PayloadBranch: data.Data.Attested.ExecutionBranch,
+		},
+		Signature:     data.Data.Aggregate,
+		SignatureSlot: uint64(data.Data.SignatureSlot),
+	}, nil
+}
+
+// GetFinalityUpdate fetches the latest available finality update.
+//
+// See data structure definition here:
+// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/sync-protocol.md#lightclientfinalityupdate
+func (api *BeaconLightApi) GetFinalityUpdate() (types.FinalityUpdate, error) {
+	resp, err := api.httpGet("/eth/v1/beacon/light_client/finality_update")
+	if err != nil {
+		return types.FinalityUpdate{}, err
+	}
+	return decodeFinalityUpdate(resp)
+}
+
+func decodeFinalityUpdate(enc []byte) (types.FinalityUpdate, error) {
+	var data struct {
+		Version string
+		Data    struct {
+			Attested       jsonHeaderWithExecProof `json:"attested_header"`
+			Finalized      jsonHeaderWithExecProof `json:"finalized_header"`
+			FinalityBranch merkle.Values           `json:"finality_branch"`
+			Aggregate      types.SyncAggregate     `json:"sync_aggregate"`
+			SignatureSlot  common.Decimal          `json:"signature_slot"`
+		}
+	}
+	if err := json.Unmarshal(enc, &data); err != nil {
+		return types.FinalityUpdate{}, err
+	}
+	// Decode the execution payload headers.
+	attestedExecHeader, err := types.ExecutionHeaderFromJSON(data.Version, data.Data.Attested.Execution)
+	if err != nil {
+		return types.FinalityUpdate{}, fmt.Errorf("invalid attested header: %v", err)
+	}
+	finalizedExecHeader, err := types.ExecutionHeaderFromJSON(data.Version, data.Data.Finalized.Execution)
+	if err != nil {
+		return types.FinalityUpdate{}, fmt.Errorf("invalid finalized header: %v", err)
+	}
+	// Perform sanity checks.
+	if len(data.Data.Aggregate.Signers) != params.SyncCommitteeBitmaskSize {
+		return types.FinalityUpdate{}, errors.New("invalid sync_committee_bits length")
+	}
+	if len(data.Data.Aggregate.Signature) != params.BLSSignatureSize {
+		return types.FinalityUpdate{}, errors.New("invalid sync_committee_signature length")
+	}
+
+	return types.FinalityUpdate{
+		Attested: types.HeaderWithExecProof{
+			Header:        data.Data.Attested.Beacon,
+			PayloadHeader: attestedExecHeader,
+			PayloadBranch: data.Data.Attested.ExecutionBranch,
+		},
+		Finalized: types.HeaderWithExecProof{
+			Header:        data.Data.Finalized.Beacon,
+			PayloadHeader: finalizedExecHeader,
+			PayloadBranch: data.Data.Finalized.ExecutionBranch,
+		},
+		FinalityBranch: data.Data.FinalityBranch,
+		Signature:      data.Data.Aggregate,
+		SignatureSlot:  uint64(data.Data.SignatureSlot),
+	}, nil
+}
+
+// GetHeader fetches and validates the beacon header with the given blockRoot.
+// If blockRoot is null hash then the latest head header is fetched.
+// The values of the canonical and finalized flags are also returned. Note that
+// these flags are not validated.
+func (api *BeaconLightApi) GetHeader(blockRoot common.Hash) (types.Header, bool, bool, error) {
+	var blockId string
+	if blockRoot == (common.Hash{}) {
+		blockId = "head"
+	} else {
+		blockId = blockRoot.Hex()
+	}
+	resp, err := api.httpGetf("/eth/v1/beacon/headers/%s", blockId)
+	if err != nil {
+		return types.Header{}, false, false, err
+	}
+
+	var data struct {
+		Finalized bool `json:"finalized"`
+		Data      struct {
+			Root      common.Hash `json:"root"`
+			Canonical bool        `json:"canonical"`
+			Header    struct {
+				Message   types.Header  `json:"message"`
+				Signature hexutil.Bytes `json:"signature"`
+			} `json:"header"`
+		} `json:"data"`
+	}
+	if err := json.Unmarshal(resp, &data); err != nil {
+		return types.Header{}, false, false, err
+	}
+	header := data.Data.Header.Message
+	if blockRoot == (common.Hash{}) {
+		blockRoot = data.Data.Root
+	}
+	if header.Hash() != blockRoot {
+		return types.Header{}, false, false, errors.New("retrieved beacon header root does not match")
+	}
+	return header, data.Data.Canonical, data.Finalized, nil
+}
+
+// GetCheckpointData fetches and validates bootstrap data belonging to the given checkpoint.
+func (api *BeaconLightApi) GetCheckpointData(checkpointHash common.Hash) (*types.BootstrapData, error) {
+	resp, err := api.httpGetf("/eth/v1/beacon/light_client/bootstrap/0x%x", checkpointHash[:])
+	if err != nil {
+		return nil, err
+	}
+
+	// See data structure definition here:
+	// https://github.com/ethereum/consensus-specs/blob/dev/specs/altair/light-client/sync-protocol.md#lightclientbootstrap
+	type bootstrapData struct {
+		Data struct {
+			Header          jsonBeaconHeader               `json:"header"`
+			Committee       *types.SerializedSyncCommittee `json:"current_sync_committee"`
+			CommitteeBranch merkle.Values                  `json:"current_sync_committee_branch"`
+		} `json:"data"`
+	}
+
+	var data bootstrapData
+	if err := json.Unmarshal(resp, &data); err != nil {
+		return nil, err
+	}
+	if data.Data.Committee == nil {
+		return nil, errors.New("sync committee is missing")
+	}
+	header := data.Data.Header.Beacon
+	if header.Hash() != checkpointHash {
+		return nil, fmt.Errorf("invalid checkpoint block header, have %v want %v", header.Hash(), checkpointHash)
+	}
+	checkpoint := &types.BootstrapData{
+		Header:          header,
+		CommitteeBranch: data.Data.CommitteeBranch,
+		CommitteeRoot:   data.Data.Committee.Root(),
+		Committee:       data.Data.Committee,
+	}
+	if err := checkpoint.Validate(); err != nil {
+		return nil, fmt.Errorf("invalid checkpoint: %w", err)
+	}
+	if checkpoint.Header.Hash() != checkpointHash {
+		return nil, errors.New("wrong checkpoint hash")
+	}
+	return checkpoint, nil
+}
+
+func (api *BeaconLightApi) GetBeaconBlock(blockRoot common.Hash) (*types.BeaconBlock, error) {
+	resp, err := api.httpGetf("/eth/v2/beacon/blocks/0x%x", blockRoot)
+	if err != nil {
+		return nil, err
+	}
+
+	var beaconBlockMessage struct {
+		Version string
+		Data    struct {
+			Message json.RawMessage `json:"message"`
+		}
+	}
+	if err := json.Unmarshal(resp, &beaconBlockMessage); err != nil {
+		return nil, fmt.Errorf("invalid block json data: %v", err)
+	}
+	block, err := types.BlockFromJSON(beaconBlockMessage.Version, beaconBlockMessage.Data.Message)
+	if err != nil {
+		return nil, err
+	}
+	computedRoot := block.Root()
+	if computedRoot != blockRoot {
+		return nil, fmt.Errorf("Beacon block root hash mismatch (expected: %x, got: %x)", blockRoot, computedRoot)
+	}
+	return block, nil
+}
+
+func decodeHeadEvent(enc []byte) (uint64, common.Hash, error) {
+	var data struct {
+		Slot  common.Decimal `json:"slot"`
+		Block common.Hash    `json:"block"`
+	}
+	if err := json.Unmarshal(enc, &data); err != nil {
+		return 0, common.Hash{}, err
+	}
+	return uint64(data.Slot), data.Block, nil
+}
+
+type HeadEventListener struct {
+	OnNewHead    func(slot uint64, blockRoot common.Hash)
+	OnOptimistic func(head types.OptimisticUpdate)
+	OnFinality   func(head types.FinalityUpdate)
+	OnError      func(err error)
+}
+
+// StartHeadListener creates an event subscription for heads and signed (optimistic)
+// head updates and calls the specified callback functions when they are received.
+// The callbacks are also called for the current head and optimistic head at startup.
+// They are never called concurrently.
+func (api *BeaconLightApi) StartHeadListener(listener HeadEventListener) func() {
+	var (
+		ctx, closeCtx = context.WithCancel(context.Background())
+		streamCh      = make(chan *eventsource.Stream, 1)
+		wg            sync.WaitGroup
+	)
+
+	// When connected to a Lodestar node the subscription blocks until the first actual
+	// event arrives; therefore we create the subscription in a separate goroutine while
+	// letting the main goroutine sync up to the current head.
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+		stream := api.startEventStream(ctx, &listener)
+		if stream == nil {
+			// This case happens when the context was closed.
+			return
+		}
+		// Stream was opened, wait for close signal.
+		streamCh <- stream
+		<-ctx.Done()
+		stream.Close()
+	}()
+
+	wg.Add(1)
+	go func() {
+		defer wg.Done()
+
+		// Request initial data.
+		log.Trace("Requesting initial head header")
+		if head, _, _, err := api.GetHeader(common.Hash{}); err == nil {
+			log.Trace("Retrieved initial head header", "slot", head.Slot, "hash", head.Hash())
+			listener.OnNewHead(head.Slot, head.Hash())
+		} else {
+			log.Debug("Failed to retrieve initial head header", "error", err)
+		}
+		log.Trace("Requesting initial optimistic update")
+		if optimisticUpdate, err := api.GetOptimisticUpdate(); err == nil {
+			log.Trace("Retrieved initial optimistic update", "slot", optimisticUpdate.Attested.Slot, "hash", optimisticUpdate.Attested.Hash())
+			listener.OnOptimistic(optimisticUpdate)
+		} else {
+			log.Debug("Failed to retrieve initial optimistic update", "error", err)
+		}
+		log.Trace("Requesting initial finality update")
+		if finalityUpdate, err := api.GetFinalityUpdate(); err == nil {
+			log.Trace("Retrieved initial finality update", "slot", finalityUpdate.Finalized.Slot, "hash", finalityUpdate.Finalized.Hash())
+			listener.OnFinality(finalityUpdate)
+		} else {
+			log.Debug("Failed to retrieve initial finality update", "error", err)
+		}
+
+		log.Trace("Starting event stream processing loop")
+		// Receive the stream.
+		var stream *eventsource.Stream
+		select {
+		case stream = <-streamCh:
+		case <-ctx.Done():
+			log.Trace("Stopping event stream processing loop")
+			return
+		}
+
+		for {
+			select {
+			case event, ok := <-stream.Events:
+				if !ok {
+					log.Trace("Event stream closed")
+					return
+				}
+				log.Trace("New event received from event stream", "type", event.Event())
+				switch event.Event() {
+				case "head":
+					slot, blockRoot, err := decodeHeadEvent([]byte(event.Data()))
+					if err == nil {
+						listener.OnNewHead(slot, blockRoot)
+					} else {
+						listener.OnError(fmt.Errorf("error decoding head event: %v", err))
+					}
+				case "light_client_optimistic_update":
+					optimisticUpdate, err := decodeOptimisticUpdate([]byte(event.Data()))
+					if err == nil {
+						listener.OnOptimistic(optimisticUpdate)
+					} else {
+						listener.OnError(fmt.Errorf("error decoding optimistic update event: %v", err))
+					}
+				case "light_client_finality_update":
+					finalityUpdate, err := decodeFinalityUpdate([]byte(event.Data()))
+					if err == nil {
+						listener.OnFinality(finalityUpdate)
+					} else {
+						listener.OnError(fmt.Errorf("error decoding finality update event: %v", err))
+					}
+				default:
+					listener.OnError(fmt.Errorf("unexpected event: %s", event.Event()))
+				}
+
+			case err, ok := <-stream.Errors:
+				if !ok {
+					return
+				}
+				listener.OnError(err)
+			}
+		}
+	}()
+
+	return func() {
+		closeCtx()
+		wg.Wait()
+	}
+}
+
+// startEventStream establishes an event stream. This will keep retrying until the stream has been
+// established. It can only return nil when the context is canceled.
+func (api *BeaconLightApi) startEventStream(ctx context.Context, listener *HeadEventListener) *eventsource.Stream {
+	for retry := true; retry; retry = ctxSleep(ctx, 5*time.Second) {
+		path := "/eth/v1/events?topics=head&topics=light_client_finality_update&topics=light_client_optimistic_update"
+		log.Trace("Sending event subscription request")
+		req, err := http.NewRequestWithContext(ctx, "GET", api.url+path, nil)
+		if err != nil {
+			listener.OnError(fmt.Errorf("error creating event subscription request: %v", err))
+			continue
+		}
+		for k, v := range api.customHeaders {
+			req.Header.Set(k, v)
+		}
+		stream, err := eventsource.SubscribeWithRequest("", req)
+		if err != nil {
+			listener.OnError(fmt.Errorf("error creating event subscription: %v", err))
+			continue
+		}
+		log.Trace("Successfully created event stream")
+		return stream
+	}
+	return nil
+}
+
+func ctxSleep(ctx context.Context, timeout time.Duration) (ok bool) {
+	timer := time.NewTimer(timeout)
+	defer timer.Stop()
+	select {
+	case <-timer.C:
+		return true
+	case <-ctx.Done():
+		return false
+	}
+}

beacon/light/canonical.go

@@ -0,0 +1,125 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package light
+
+import (
+	"encoding/binary"
+	"fmt"
+
+	"github.com/ethereum/go-ethereum/common/lru"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
+)
+
+// canonicalStore stores instances of the given type in a database and caches
+// them in memory, associated with a continuous range of period numbers.
+// Note: canonicalStore is not thread safe and it is the caller's responsibility
+// to avoid concurrent access.
+type canonicalStore[T any] struct {
+	keyPrefix []byte
+	periods   periodRange
+	cache     *lru.Cache[uint64, T]
+}
+
+// newCanonicalStore creates a new canonicalStore and loads all keys associated
+// with the keyPrefix in order to determine the ranges available in the database.
+func newCanonicalStore[T any](db ethdb.Iteratee, keyPrefix []byte) (*canonicalStore[T], error) {
+	cs := &canonicalStore[T]{
+		keyPrefix: keyPrefix,
+		cache:     lru.NewCache[uint64, T](100),
+	}
+	var (
+		iter  = db.NewIterator(keyPrefix, nil)
+		kl    = len(keyPrefix)
+		first = true
+	)
+	defer iter.Release()
+
+	for iter.Next() {
+		if len(iter.Key()) != kl+8 {
+			log.Warn("Invalid key length in the canonical chain database", "key", fmt.Sprintf("%#x", iter.Key()))
+			continue
+		}
+		period := binary.BigEndian.Uint64(iter.Key()[kl : kl+8])
+		if first {
+			cs.periods.Start = period
+		} else if cs.periods.End != period {
+			return nil, fmt.Errorf("gap in the canonical chain database between periods %d and %d", cs.periods.End, period-1)
+		}
+		first = false
+		cs.periods.End = period + 1
+	}
+	return cs, nil
+}
+
+// databaseKey returns the database key belonging to the given period.
+func (cs *canonicalStore[T]) databaseKey(period uint64) []byte {
+	return binary.BigEndian.AppendUint64(append([]byte{}, cs.keyPrefix...), period)
+}
+
+// add adds the given item to the database. It also ensures that the range remains
+// continuous. Can be used either with a batch or database backend.
+func (cs *canonicalStore[T]) add(backend ethdb.KeyValueWriter, period uint64, value T) error {
+	if !cs.periods.canExpand(period) {
+		return fmt.Errorf("period expansion is not allowed, first: %d, next: %d, period: %d", cs.periods.Start, cs.periods.End, period)
+	}
+	enc, err := rlp.EncodeToBytes(value)
+	if err != nil {
+		return err
+	}
+	if err := backend.Put(cs.databaseKey(period), enc); err != nil {
+		return err
+	}
+	cs.cache.Add(period, value)
+	cs.periods.expand(period)
+	return nil
+}
+
+// deleteFrom removes items starting from the given period.
+func (cs *canonicalStore[T]) deleteFrom(db ethdb.KeyValueWriter, fromPeriod uint64) (deleted periodRange) {
+	keepRange, deleteRange := cs.periods.split(fromPeriod)
+	deleteRange.each(func(period uint64) {
+		db.Delete(cs.databaseKey(period))
+		cs.cache.Remove(period)
+	})
+	cs.periods = keepRange
+	return deleteRange
+}
+
+// get returns the item at the given period or the null value of the given type
+// if no item is present.
+func (cs *canonicalStore[T]) get(backend ethdb.KeyValueReader, period uint64) (T, bool) {
+	var null, value T
+	if !cs.periods.contains(period) {
+		return null, false
+	}
+	if value, ok := cs.cache.Get(period); ok {
+		return value, true
+	}
+	enc, err := backend.Get(cs.databaseKey(period))
+	if err != nil {
+		log.Error("Canonical store value not found", "period", period, "start", cs.periods.Start, "end", cs.periods.End)
+		return null, false
+	}
+	if err := rlp.DecodeBytes(enc, &value); err != nil {
+		log.Error("Error decoding canonical store value", "error", err)
+		return null, false
+	}
+	cs.cache.Add(period, value)
+	return value, true
+}

beacon/light/committee_chain.go

@@ -0,0 +1,529 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package light
+
+import (
+	"errors"
+	"fmt"
+	"math"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/beacon/params"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/lru"
+	"github.com/ethereum/go-ethereum/common/mclock"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+var (
+	ErrNeedCommittee      = errors.New("sync committee required")
+	ErrInvalidUpdate      = errors.New("invalid committee update")
+	ErrInvalidPeriod      = errors.New("invalid update period")
+	ErrWrongCommitteeRoot = errors.New("wrong committee root")
+	ErrCannotReorg        = errors.New("can not reorg committee chain")
+)
+
+// CommitteeChain is a passive data structure that can validate, hold and update
+// a chain of beacon light sync committees and updates. It requires at least one
+// externally set fixed committee root at the beginning of the chain which can
+// be set either based on a BootstrapData or a trusted source (a local beacon
+// full node). This makes the structure useful for both light client and light
+// server setups.
+//
+// It always maintains the following consistency constraints:
+//   - a committee can only be present if its root hash matches an existing fixed
+//     root or if it is proven by an update at the previous period
+//   - an update can only be present if a committee is present at the same period
+//     and the update signature is valid and has enough participants.
+//     The committee at the next period (proven by the update) should also be
+//     present (note that this means they can only be added together if neither
+//     is present yet). If a fixed root is present at the next period then the
+//     update can only be present if it proves the same committee root.
+//
+// Once synced to the current sync period, CommitteeChain can also validate
+// signed beacon headers.
+type CommitteeChain struct {
+	// chainmu guards against concurrent access to the canonicalStore structures
+	// (updates, committees, fixedCommitteeRoots) and ensures that they stay consistent
+	// with each other and with committeeCache.
+	chainmu             sync.RWMutex
+	db                  ethdb.KeyValueStore
+	updates             *canonicalStore[*types.LightClientUpdate]
+	committees          *canonicalStore[*types.SerializedSyncCommittee]
+	fixedCommitteeRoots *canonicalStore[common.Hash]
+	committeeCache      *lru.Cache[uint64, syncCommittee] // cache deserialized committees
+	changeCounter       uint64
+
+	clock       mclock.Clock         // monotonic clock (simulated clock in tests)
+	unixNano    func() int64         // system clock (simulated clock in tests)
+	sigVerifier committeeSigVerifier // BLS sig verifier (dummy verifier in tests)
+
+	config             *types.ChainConfig
+	signerThreshold    int
+	minimumUpdateScore types.UpdateScore
+	enforceTime        bool // enforceTime specifies whether the age of a signed header should be checked
+}
+
+// NewCommitteeChain creates a new CommitteeChain.
+func NewCommitteeChain(db ethdb.KeyValueStore, config *types.ChainConfig, signerThreshold int, enforceTime bool) *CommitteeChain {
+	return newCommitteeChain(db, config, signerThreshold, enforceTime, blsVerifier{}, &mclock.System{}, func() int64 { return time.Now().UnixNano() })
+}
+
+// NewTestCommitteeChain creates a new CommitteeChain for testing.
+func NewTestCommitteeChain(db ethdb.KeyValueStore, config *types.ChainConfig, signerThreshold int, enforceTime bool, clock *mclock.Simulated) *CommitteeChain {
+	return newCommitteeChain(db, config, signerThreshold, enforceTime, dummyVerifier{}, clock, func() int64 { return int64(clock.Now()) })
+}
+
+// newCommitteeChain creates a new CommitteeChain with the option of replacing the
+// clock source and signature verification for testing purposes.
+func newCommitteeChain(db ethdb.KeyValueStore, config *types.ChainConfig, signerThreshold int, enforceTime bool, sigVerifier committeeSigVerifier, clock mclock.Clock, unixNano func() int64) *CommitteeChain {
+	s := &CommitteeChain{
+		committeeCache:  lru.NewCache[uint64, syncCommittee](10),
+		db:              db,
+		sigVerifier:     sigVerifier,
+		clock:           clock,
+		unixNano:        unixNano,
+		config:          config,
+		signerThreshold: signerThreshold,
+		enforceTime:     enforceTime,
+		minimumUpdateScore: types.UpdateScore{
+			SignerCount:    uint32(signerThreshold),
+			SubPeriodIndex: params.SyncPeriodLength / 16,
+		},
+	}
+
+	var err1, err2, err3 error
+	if s.fixedCommitteeRoots, err1 = newCanonicalStore[common.Hash](db, rawdb.FixedCommitteeRootKey); err1 != nil {
+		log.Error("Error creating fixed committee root store", "error", err1)
+	}
+	if s.committees, err2 = newCanonicalStore[*types.SerializedSyncCommittee](db, rawdb.SyncCommitteeKey); err2 != nil {
+		log.Error("Error creating committee store", "error", err2)
+	}
+	if s.updates, err3 = newCanonicalStore[*types.LightClientUpdate](db, rawdb.BestUpdateKey); err3 != nil {
+		log.Error("Error creating update store", "error", err3)
+	}
+	if err1 != nil || err2 != nil || err3 != nil || !s.checkConstraints() {
+		log.Info("Resetting invalid committee chain")
+		s.Reset()
+	}
+	// roll back invalid updates (might be necessary if forks have been changed since last time)
+	for !s.updates.periods.isEmpty() {
+		update, ok := s.updates.get(s.db, s.updates.periods.End-1)
+		if !ok {
+			log.Error("Sync committee update missing", "period", s.updates.periods.End-1)
+			s.Reset()
+			break
+		}
+		if valid, err := s.verifyUpdate(update); err != nil {
+			log.Error("Error validating update", "period", s.updates.periods.End-1, "error", err)
+		} else if valid {
+			break
+		}
+		if err := s.rollback(s.updates.periods.End); err != nil {
+			log.Error("Error writing batch into chain database", "error", err)
+		}
+	}
+	if !s.committees.periods.isEmpty() {
+		log.Trace("Sync committee chain loaded", "first period", s.committees.periods.Start, "last period", s.committees.periods.End-1)
+	}
+	return s
+}
+
+// checkConstraints checks committee chain validity constraints
+func (s *CommitteeChain) checkConstraints() bool {
+	isNotInFixedCommitteeRootRange := func(r periodRange) bool {
+		return s.fixedCommitteeRoots.periods.isEmpty() ||
+			r.Start < s.fixedCommitteeRoots.periods.Start ||
+			r.Start >= s.fixedCommitteeRoots.periods.End
+	}
+
+	valid := true
+	if !s.updates.periods.isEmpty() {
+		if isNotInFixedCommitteeRootRange(s.updates.periods) {
+			log.Error("Start update is not in the fixed roots range")
+			valid = false
+		}
+		if s.committees.periods.Start > s.updates.periods.Start || s.committees.periods.End <= s.updates.periods.End {
+			log.Error("Missing committees in update range")
+			valid = false
+		}
+	}
+	if !s.committees.periods.isEmpty() {
+		if isNotInFixedCommitteeRootRange(s.committees.periods) {
+			log.Error("Start committee is not in the fixed roots range")
+			valid = false
+		}
+		if s.committees.periods.End > s.fixedCommitteeRoots.periods.End && s.committees.periods.End > s.updates.periods.End+1 {
+			log.Error("Last committee is neither in the fixed roots range nor proven by updates")
+			valid = false
+		}
+	}
+	return valid
+}
+
+// Reset resets the committee chain.
+func (s *CommitteeChain) Reset() {
+	s.chainmu.Lock()
+	defer s.chainmu.Unlock()
+
+	if err := s.rollback(0); err != nil {
+		log.Error("Error writing batch into chain database", "error", err)
+	}
+	s.changeCounter++
+}
+
+// CheckpointInit initializes a CommitteeChain based on a checkpoint.
+// Note: if the chain is already initialized and the committees proven by the
+// checkpoint do match the existing chain then the chain is retained and the
+// new checkpoint becomes fixed.
+func (s *CommitteeChain) CheckpointInit(bootstrap types.BootstrapData) error {
+	s.chainmu.Lock()
+	defer s.chainmu.Unlock()
+
+	if err := bootstrap.Validate(); err != nil {
+		return err
+	}
+	period := bootstrap.Header.SyncPeriod()
+	if err := s.deleteFixedCommitteeRootsFrom(period + 2); err != nil {
+		s.Reset()
+		return err
+	}
+	if s.addFixedCommitteeRoot(period, bootstrap.CommitteeRoot) != nil {
+		s.Reset()
+		if err := s.addFixedCommitteeRoot(period, bootstrap.CommitteeRoot); err != nil {
+			s.Reset()
+			return err
+		}
+	}
+	if err := s.addFixedCommitteeRoot(period+1, common.Hash(bootstrap.CommitteeBranch[0])); err != nil {
+		s.Reset()
+		return err
+	}
+	if err := s.addCommittee(period, bootstrap.Committee); err != nil {
+		s.Reset()
+		return err
+	}
+	s.changeCounter++
+	return nil
+}
+
+// addFixedCommitteeRoot sets a fixed committee root at the given period.
+// Note that the period where the first committee is added has to have a fixed
+// root which can either come from a BootstrapData or a trusted source.
+func (s *CommitteeChain) addFixedCommitteeRoot(period uint64, root common.Hash) error {
+	if root == (common.Hash{}) {
+		return ErrWrongCommitteeRoot
+	}
+
+	batch := s.db.NewBatch()
+	oldRoot := s.getCommitteeRoot(period)
+	if !s.fixedCommitteeRoots.periods.canExpand(period) {
+		// Note: the fixed committee root range should always be continuous and
+		// therefore the expected syncing method is to forward sync and optionally
+		// backward sync periods one by one, starting from a checkpoint. The only
+		// case when a root that is not adjacent to the already fixed ones can be
+		// fixed is when the same root has already been proven by an update chain.
+		// In this case the all roots in between can and should be fixed.
+		// This scenario makes sense when a new trusted checkpoint is added to an
+		// existing chain, ensuring that it will not be rolled back (might be
+		// important in case of low signer participation rate).
+		if root != oldRoot {
+			return ErrInvalidPeriod
+		}
+		// if the old root exists and matches the new one then it is guaranteed
+		// that the given period is after the existing fixed range and the roots
+		// in between can also be fixed.
+		for p := s.fixedCommitteeRoots.periods.End; p < period; p++ {
+			if err := s.fixedCommitteeRoots.add(batch, p, s.getCommitteeRoot(p)); err != nil {
+				return err
+			}
+		}
+	}
+	if oldRoot != (common.Hash{}) && (oldRoot != root) {
+		// existing old root was different, we have to reorg the chain
+		if err := s.rollback(period); err != nil {
+			return err
+		}
+	}
+	if err := s.fixedCommitteeRoots.add(batch, period, root); err != nil {
+		return err
+	}
+	if err := batch.Write(); err != nil {
+		log.Error("Error writing batch into chain database", "error", err)
+		return err
+	}
+	return nil
+}
+
+// deleteFixedCommitteeRootsFrom deletes fixed roots starting from the given period.
+// It also maintains chain consistency, meaning that it also deletes updates and
+// committees if they are no longer supported by a valid update chain.
+func (s *CommitteeChain) deleteFixedCommitteeRootsFrom(period uint64) error {
+	if period >= s.fixedCommitteeRoots.periods.End {
+		return nil
+	}
+	batch := s.db.NewBatch()
+	s.fixedCommitteeRoots.deleteFrom(batch, period)
+	if s.updates.periods.isEmpty() || period <= s.updates.periods.Start {
+		// Note: the first period of the update chain should always be fixed so if
+		// the fixed root at the first update is removed then the entire update chain
+		// and the proven committees have to be removed. Earlier committees in the
+		// remaining fixed root range can stay.
+		s.updates.deleteFrom(batch, period)
+		s.deleteCommitteesFrom(batch, period)
+	} else {
+		// The update chain stays intact, some previously fixed committee roots might
+		// get unfixed but are still proven by the update chain. If there were
+		// committees present after the range proven by updates, those should be
+		// removed if the belonging fixed roots are also removed.
+		fromPeriod := s.updates.periods.End + 1 // not proven by updates
+		if period > fromPeriod {
+			fromPeriod = period // also not justified by fixed roots
+		}
+		s.deleteCommitteesFrom(batch, fromPeriod)
+	}
+	if err := batch.Write(); err != nil {
+		log.Error("Error writing batch into chain database", "error", err)
+		return err
+	}
+	return nil
+}
+
+// deleteCommitteesFrom deletes committees starting from the given period.
+func (s *CommitteeChain) deleteCommitteesFrom(batch ethdb.Batch, period uint64) {
+	deleted := s.committees.deleteFrom(batch, period)
+	for period := deleted.Start; period < deleted.End; period++ {
+		s.committeeCache.Remove(period)
+	}
+}
+
+// addCommittee adds a committee at the given period if possible.
+func (s *CommitteeChain) addCommittee(period uint64, committee *types.SerializedSyncCommittee) error {
+	if !s.committees.periods.canExpand(period) {
+		return ErrInvalidPeriod
+	}
+	root := s.getCommitteeRoot(period)
+	if root == (common.Hash{}) {
+		return ErrInvalidPeriod
+	}
+	if root != committee.Root() {
+		return ErrWrongCommitteeRoot
+	}
+	if !s.committees.periods.contains(period) {
+		if err := s.committees.add(s.db, period, committee); err != nil {
+			return err
+		}
+		s.committeeCache.Remove(period)
+	}
+	return nil
+}
+
+// InsertUpdate adds a new update if possible.
+func (s *CommitteeChain) InsertUpdate(update *types.LightClientUpdate, nextCommittee *types.SerializedSyncCommittee) error {
+	s.chainmu.Lock()
+	defer s.chainmu.Unlock()
+
+	period := update.AttestedHeader.Header.SyncPeriod()
+	if !s.updates.periods.canExpand(period) || !s.committees.periods.contains(period) {
+		return ErrInvalidPeriod
+	}
+	if s.minimumUpdateScore.BetterThan(update.Score()) {
+		return ErrInvalidUpdate
+	}
+	oldRoot := s.getCommitteeRoot(period + 1)
+	reorg := oldRoot != (common.Hash{}) && oldRoot != update.NextSyncCommitteeRoot
+	if oldUpdate, ok := s.updates.get(s.db, period); ok && !update.Score().BetterThan(oldUpdate.Score()) {
+		// a better or equal update already exists; no changes, only fail if new one tried to reorg
+		if reorg {
+			return ErrCannotReorg
+		}
+		return nil
+	}
+	if s.fixedCommitteeRoots.periods.contains(period+1) && reorg {
+		return ErrCannotReorg
+	}
+	if ok, err := s.verifyUpdate(update); err != nil {
+		return err
+	} else if !ok {
+		return ErrInvalidUpdate
+	}
+	addCommittee := !s.committees.periods.contains(period+1) || reorg
+	if addCommittee {
+		if nextCommittee == nil {
+			return ErrNeedCommittee
+		}
+		if nextCommittee.Root() != update.NextSyncCommitteeRoot {
+			return ErrWrongCommitteeRoot
+		}
+	}
+	s.changeCounter++
+	if reorg {
+		if err := s.rollback(period + 1); err != nil {
+			return err
+		}
+	}
+	batch := s.db.NewBatch()
+	if addCommittee {
+		if err := s.committees.add(batch, period+1, nextCommittee); err != nil {
+			return err
+		}
+		s.committeeCache.Remove(period + 1)
+	}
+	if err := s.updates.add(batch, period, update); err != nil {
+		return err
+	}
+	if err := batch.Write(); err != nil {
+		log.Error("Error writing batch into chain database", "error", err)
+		return err
+	}
+	log.Info("Inserted new committee update", "period", period, "next committee root", update.NextSyncCommitteeRoot)
+	return nil
+}
+
+// NextSyncPeriod returns the next period where an update can be added and also
+// whether the chain is initialized at all.
+func (s *CommitteeChain) NextSyncPeriod() (uint64, bool) {
+	s.chainmu.RLock()
+	defer s.chainmu.RUnlock()
+
+	if s.committees.periods.isEmpty() {
+		return 0, false
+	}
+	if !s.updates.periods.isEmpty() {
+		return s.updates.periods.End, true
+	}
+	return s.committees.periods.End - 1, true
+}
+
+func (s *CommitteeChain) ChangeCounter() uint64 {
+	s.chainmu.RLock()
+	defer s.chainmu.RUnlock()
+
+	return s.changeCounter
+}
+
+// rollback removes all committees and fixed roots from the given period and updates
+// starting from the previous period.
+func (s *CommitteeChain) rollback(period uint64) error {
+	max := s.updates.periods.End + 1
+	if s.committees.periods.End > max {
+		max = s.committees.periods.End
+	}
+	if s.fixedCommitteeRoots.periods.End > max {
+		max = s.fixedCommitteeRoots.periods.End
+	}
+	for max > period {
+		max--
+		batch := s.db.NewBatch()
+		s.deleteCommitteesFrom(batch, max)
+		s.fixedCommitteeRoots.deleteFrom(batch, max)
+		if max > 0 {
+			s.updates.deleteFrom(batch, max-1)
+		}
+		if err := batch.Write(); err != nil {
+			log.Error("Error writing batch into chain database", "error", err)
+			return err
+		}
+	}
+	return nil
+}
+
+// getCommitteeRoot returns the committee root at the given period, either fixed,
+// proven by a previous update or both. It returns an empty hash if the committee
+// root is unknown.
+func (s *CommitteeChain) getCommitteeRoot(period uint64) common.Hash {
+	if root, ok := s.fixedCommitteeRoots.get(s.db, period); ok || period == 0 {
+		return root
+	}
+	if update, ok := s.updates.get(s.db, period-1); ok {
+		return update.NextSyncCommitteeRoot
+	}
+	return common.Hash{}
+}
+
+// getSyncCommittee returns the deserialized sync committee at the given period.
+func (s *CommitteeChain) getSyncCommittee(period uint64) (syncCommittee, error) {
+	if c, ok := s.committeeCache.Get(period); ok {
+		return c, nil
+	}
+	if sc, ok := s.committees.get(s.db, period); ok {
+		c, err := s.sigVerifier.deserializeSyncCommittee(sc)
+		if err != nil {
+			return nil, fmt.Errorf("sync committee #%d deserialization error: %v", period, err)
+		}
+		s.committeeCache.Add(period, c)
+		return c, nil
+	}
+	return nil, fmt.Errorf("missing serialized sync committee #%d", period)
+}
+
+// VerifySignedHeader returns true if the given signed header has a valid signature
+// according to the local committee chain. The caller should ensure that the
+// committees advertised by the same source where the signed header came from are
+// synced before verifying the signature.
+// The age of the header is also returned (the time elapsed since the beginning
+// of the given slot, according to the local system clock). If enforceTime is
+// true then negative age (future) headers are rejected.
+func (s *CommitteeChain) VerifySignedHeader(head types.SignedHeader) (bool, time.Duration, error) {
+	s.chainmu.RLock()
+	defer s.chainmu.RUnlock()
+
+	return s.verifySignedHeader(head)
+}
+
+func (s *CommitteeChain) verifySignedHeader(head types.SignedHeader) (bool, time.Duration, error) {
+	var age time.Duration
+	now := s.unixNano()
+	if head.Header.Slot < (uint64(now-math.MinInt64)/uint64(time.Second)-s.config.GenesisTime)/12 {
+		age = time.Duration(now - int64(time.Second)*int64(s.config.GenesisTime+head.Header.Slot*12))
+	} else {
+		age = time.Duration(math.MinInt64)
+	}
+	if s.enforceTime && age < 0 {
+		return false, age, nil
+	}
+	committee, err := s.getSyncCommittee(types.SyncPeriod(head.SignatureSlot))
+	if err != nil {
+		return false, 0, err
+	}
+	if committee == nil {
+		return false, age, nil
+	}
+	if signingRoot, err := s.config.Forks.SigningRoot(head.Header); err == nil {
+		return s.sigVerifier.verifySignature(committee, signingRoot, &head.Signature), age, nil
+	}
+	return false, age, nil
+}
+
+// verifyUpdate checks whether the header signature is correct and the update
+// fits into the specified constraints (assumes that the update has been
+// successfully validated previously)
+func (s *CommitteeChain) verifyUpdate(update *types.LightClientUpdate) (bool, error) {
+	// Note: SignatureSlot determines the sync period of the committee used for signature
+	// verification. Though in reality SignatureSlot is always bigger than update.Header.Slot,
+	// setting them as equal here enforces the rule that they have to be in the same sync
+	// period in order for the light client update proof to be meaningful.
+	ok, age, err := s.verifySignedHeader(update.AttestedHeader)
+	if age < 0 {
+		log.Warn("Future committee update received", "age", age)
+	}
+	return ok, err
+}

beacon/light/committee_chain_test.go

@@ -0,0 +1,356 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package light
+
+import (
+	"crypto/rand"
+	"testing"
+	"time"
+
+	"github.com/ethereum/go-ethereum/beacon/params"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common/mclock"
+	"github.com/ethereum/go-ethereum/ethdb/memorydb"
+)
+
+var (
+	testGenesis  = newTestGenesis()
+	testGenesis2 = newTestGenesis()
+
+	tfBase = newTestForks(testGenesis, types.Forks{
+		&types.Fork{Epoch: 0, Version: []byte{0}},
+	})
+	tfAlternative = newTestForks(testGenesis, types.Forks{
+		&types.Fork{Epoch: 0, Version: []byte{0}},
+		&types.Fork{Epoch: 0x700, Version: []byte{1}},
+	})
+	tfAnotherGenesis = newTestForks(testGenesis2, types.Forks{
+		&types.Fork{Epoch: 0, Version: []byte{0}},
+	})
+
+	tcBase                      = newTestCommitteeChain(nil, tfBase, true, 0, 10, 400, false)
+	tcBaseWithInvalidUpdates    = newTestCommitteeChain(tcBase, tfBase, false, 5, 10, 200, false) // signer count too low
+	tcBaseWithBetterUpdates     = newTestCommitteeChain(tcBase, tfBase, false, 5, 10, 440, false)
+	tcReorgWithWorseUpdates     = newTestCommitteeChain(tcBase, tfBase, true, 5, 10, 400, false)
+	tcReorgWithWorseUpdates2    = newTestCommitteeChain(tcBase, tfBase, true, 5, 10, 380, false)
+	tcReorgWithBetterUpdates    = newTestCommitteeChain(tcBase, tfBase, true, 5, 10, 420, false)
+	tcReorgWithFinalizedUpdates = newTestCommitteeChain(tcBase, tfBase, true, 5, 10, 400, true)
+	tcFork                      = newTestCommitteeChain(tcBase, tfAlternative, true, 7, 10, 400, false)
+	tcAnotherGenesis            = newTestCommitteeChain(nil, tfAnotherGenesis, true, 0, 10, 400, false)
+)
+
+func TestCommitteeChainFixedCommitteeRoots(t *testing.T) {
+	for _, reload := range []bool{false, true} {
+		c := newCommitteeChainTest(t, tfBase, 300, true)
+		c.setClockPeriod(7)
+		c.addFixedCommitteeRoot(tcBase, 4, nil)
+		c.addFixedCommitteeRoot(tcBase, 5, nil)
+		c.addFixedCommitteeRoot(tcBase, 6, nil)
+		c.addFixedCommitteeRoot(tcBase, 8, ErrInvalidPeriod) // range has to be continuous
+		c.addFixedCommitteeRoot(tcBase, 3, nil)
+		c.addFixedCommitteeRoot(tcBase, 2, nil)
+		if reload {
+			c.reloadChain()
+		}
+		c.addCommittee(tcBase, 4, nil)
+		c.addCommittee(tcBase, 6, ErrInvalidPeriod) // range has to be continuous
+		c.addCommittee(tcBase, 5, nil)
+		c.addCommittee(tcBase, 6, nil)
+		c.addCommittee(tcAnotherGenesis, 3, ErrWrongCommitteeRoot)
+		c.addCommittee(tcBase, 3, nil)
+		if reload {
+			c.reloadChain()
+		}
+		c.verifyRange(tcBase, 3, 6)
+	}
+}
+
+func TestCommitteeChainCheckpointSync(t *testing.T) {
+	for _, enforceTime := range []bool{false, true} {
+		for _, reload := range []bool{false, true} {
+			c := newCommitteeChainTest(t, tfBase, 300, enforceTime)
+			if enforceTime {
+				c.setClockPeriod(6)
+			}
+			c.insertUpdate(tcBase, 3, true, ErrInvalidPeriod)
+			c.addFixedCommitteeRoot(tcBase, 3, nil)
+			c.addFixedCommitteeRoot(tcBase, 4, nil)
+			c.insertUpdate(tcBase, 4, true, ErrInvalidPeriod) // still no committee
+			c.addCommittee(tcBase, 3, nil)
+			c.addCommittee(tcBase, 4, nil)
+			if reload {
+				c.reloadChain()
+			}
+			c.verifyRange(tcBase, 3, 4)
+			c.insertUpdate(tcBase, 3, false, nil)              // update can be added without committee here
+			c.insertUpdate(tcBase, 4, false, ErrNeedCommittee) // but not here as committee 5 is not there yet
+			c.insertUpdate(tcBase, 4, true, nil)
+			c.verifyRange(tcBase, 3, 5)
+			c.insertUpdate(tcBaseWithInvalidUpdates, 5, true, ErrInvalidUpdate) // signer count too low
+			c.insertUpdate(tcBase, 5, true, nil)
+			if reload {
+				c.reloadChain()
+			}
+			if enforceTime {
+				c.insertUpdate(tcBase, 6, true, ErrInvalidUpdate) // future update rejected
+				c.setClockPeriod(7)
+			}
+			c.insertUpdate(tcBase, 6, true, nil) // when the time comes it's accepted
+			if reload {
+				c.reloadChain()
+			}
+			if enforceTime {
+				c.verifyRange(tcBase, 3, 6) // committee 7 is there but still in the future
+				c.setClockPeriod(8)
+			}
+			c.verifyRange(tcBase, 3, 7) // now period 7 can also be verified
+			// try reverse syncing an update
+			c.insertUpdate(tcBase, 2, false, ErrInvalidPeriod) // fixed committee is needed first
+			c.addFixedCommitteeRoot(tcBase, 2, nil)
+			c.addCommittee(tcBase, 2, nil)
+			c.insertUpdate(tcBase, 2, false, nil)
+			c.verifyRange(tcBase, 2, 7)
+		}
+	}
+}
+
+func TestCommitteeChainReorg(t *testing.T) {
+	for _, reload := range []bool{false, true} {
+		for _, addBetterUpdates := range []bool{false, true} {
+			c := newCommitteeChainTest(t, tfBase, 300, true)
+			c.setClockPeriod(11)
+			c.addFixedCommitteeRoot(tcBase, 3, nil)
+			c.addFixedCommitteeRoot(tcBase, 4, nil)
+			c.addCommittee(tcBase, 3, nil)
+			for period := uint64(3); period < 10; period++ {
+				c.insertUpdate(tcBase, period, true, nil)
+			}
+			if reload {
+				c.reloadChain()
+			}
+			c.verifyRange(tcBase, 3, 10)
+			c.insertUpdate(tcReorgWithWorseUpdates, 5, true, ErrCannotReorg)
+			c.insertUpdate(tcReorgWithWorseUpdates2, 5, true, ErrCannotReorg)
+			if addBetterUpdates {
+				// add better updates for the base chain and expect first reorg to fail
+				// (only add updates as committees should be the same)
+				for period := uint64(5); period < 10; period++ {
+					c.insertUpdate(tcBaseWithBetterUpdates, period, false, nil)
+				}
+				if reload {
+					c.reloadChain()
+				}
+				c.verifyRange(tcBase, 3, 10) // still on the same chain
+				c.insertUpdate(tcReorgWithBetterUpdates, 5, true, ErrCannotReorg)
+			} else {
+				// reorg with better updates
+				c.insertUpdate(tcReorgWithBetterUpdates, 5, false, ErrNeedCommittee)
+				c.verifyRange(tcBase, 3, 10) // no success yet, still on the base chain
+				c.verifyRange(tcReorgWithBetterUpdates, 3, 5)
+				c.insertUpdate(tcReorgWithBetterUpdates, 5, true, nil)
+				// successful reorg, base chain should only match before the reorg period
+				if reload {
+					c.reloadChain()
+				}
+				c.verifyRange(tcBase, 3, 5)
+				c.verifyRange(tcReorgWithBetterUpdates, 3, 6)
+				for period := uint64(6); period < 10; period++ {
+					c.insertUpdate(tcReorgWithBetterUpdates, period, true, nil)
+				}
+				c.verifyRange(tcReorgWithBetterUpdates, 3, 10)
+			}
+			// reorg with finalized updates; should succeed even if base chain updates
+			// have been improved because a finalized update beats everything else
+			c.insertUpdate(tcReorgWithFinalizedUpdates, 5, false, ErrNeedCommittee)
+			c.insertUpdate(tcReorgWithFinalizedUpdates, 5, true, nil)
+			if reload {
+				c.reloadChain()
+			}
+			c.verifyRange(tcReorgWithFinalizedUpdates, 3, 6)
+			for period := uint64(6); period < 10; period++ {
+				c.insertUpdate(tcReorgWithFinalizedUpdates, period, true, nil)
+			}
+			c.verifyRange(tcReorgWithFinalizedUpdates, 3, 10)
+		}
+	}
+}
+
+func TestCommitteeChainFork(t *testing.T) {
+	c := newCommitteeChainTest(t, tfAlternative, 300, true)
+	c.setClockPeriod(11)
+	// trying to sync a chain on an alternative fork with the base chain data
+	c.addFixedCommitteeRoot(tcBase, 0, nil)
+	c.addFixedCommitteeRoot(tcBase, 1, nil)
+	c.addCommittee(tcBase, 0, nil)
+	// shared section should sync without errors
+	for period := uint64(0); period < 7; period++ {
+		c.insertUpdate(tcBase, period, true, nil)
+	}
+	c.insertUpdate(tcBase, 7, true, ErrInvalidUpdate) // wrong fork
+	// committee root #7 is still the same but signatures are already signed with
+	// a different fork id so period 7 should only verify on the alternative fork
+	c.verifyRange(tcBase, 0, 6)
+	c.verifyRange(tcFork, 0, 7)
+	for period := uint64(7); period < 10; period++ {
+		c.insertUpdate(tcFork, period, true, nil)
+	}
+	c.verifyRange(tcFork, 0, 10)
+	// reload the chain while switching to the base fork
+	c.config = tfBase
+	c.reloadChain()
+	// updates 7..9 should be rolled back now
+	c.verifyRange(tcFork, 0, 6) // again, period 7 only verifies on the right fork
+	c.verifyRange(tcBase, 0, 7)
+	c.insertUpdate(tcFork, 7, true, ErrInvalidUpdate) // wrong fork
+	for period := uint64(7); period < 10; period++ {
+		c.insertUpdate(tcBase, period, true, nil)
+	}
+	c.verifyRange(tcBase, 0, 10)
+}
+
+type committeeChainTest struct {
+	t               *testing.T
+	db              *memorydb.Database
+	clock           *mclock.Simulated
+	config          types.ChainConfig
+	signerThreshold int
+	enforceTime     bool
+	chain           *CommitteeChain
+}
+
+func newCommitteeChainTest(t *testing.T, config types.ChainConfig, signerThreshold int, enforceTime bool) *committeeChainTest {
+	c := &committeeChainTest{
+		t:               t,
+		db:              memorydb.New(),
+		clock:           &mclock.Simulated{},
+		config:          config,
+		signerThreshold: signerThreshold,
+		enforceTime:     enforceTime,
+	}
+	c.chain = NewTestCommitteeChain(c.db, &config, signerThreshold, enforceTime, c.clock)
+	return c
+}
+
+func (c *committeeChainTest) reloadChain() {
+	c.chain = NewTestCommitteeChain(c.db, &c.config, c.signerThreshold, c.enforceTime, c.clock)
+}
+
+func (c *committeeChainTest) setClockPeriod(period float64) {
+	target := mclock.AbsTime(period * float64(time.Second*12*params.SyncPeriodLength))
+	wait := time.Duration(target - c.clock.Now())
+	if wait < 0 {
+		c.t.Fatalf("Invalid setClockPeriod")
+	}
+	c.clock.Run(wait)
+}
+
+func (c *committeeChainTest) addFixedCommitteeRoot(tc *testCommitteeChain, period uint64, expErr error) {
+	if err := c.chain.addFixedCommitteeRoot(period, tc.periods[period].committee.Root()); err != expErr {
+		c.t.Errorf("Incorrect error output from addFixedCommitteeRoot at period %d (expected %v, got %v)", period, expErr, err)
+	}
+}
+
+func (c *committeeChainTest) addCommittee(tc *testCommitteeChain, period uint64, expErr error) {
+	if err := c.chain.addCommittee(period, tc.periods[period].committee); err != expErr {
+		c.t.Errorf("Incorrect error output from addCommittee at period %d (expected %v, got %v)", period, expErr, err)
+	}
+}
+
+func (c *committeeChainTest) insertUpdate(tc *testCommitteeChain, period uint64, addCommittee bool, expErr error) {
+	var committee *types.SerializedSyncCommittee
+	if addCommittee {
+		committee = tc.periods[period+1].committee
+	}
+	if err := c.chain.InsertUpdate(tc.periods[period].update, committee); err != expErr {
+		c.t.Errorf("Incorrect error output from InsertUpdate at period %d (expected %v, got %v)", period, expErr, err)
+	}
+}
+
+func (c *committeeChainTest) verifySignedHeader(tc *testCommitteeChain, period float64, expOk bool) {
+	slot := uint64(period * float64(params.SyncPeriodLength))
+	signedHead := GenerateTestSignedHeader(types.Header{Slot: slot}, &tc.config, tc.periods[types.SyncPeriod(slot)].committee, slot+1, 400)
+	if ok, _, _ := c.chain.VerifySignedHeader(signedHead); ok != expOk {
+		c.t.Errorf("Incorrect output from VerifySignedHeader at period %f (expected %v, got %v)", period, expOk, ok)
+	}
+}
+
+func (c *committeeChainTest) verifyRange(tc *testCommitteeChain, begin, end uint64) {
+	if begin > 0 {
+		c.verifySignedHeader(tc, float64(begin)-0.5, false)
+	}
+	for period := begin; period <= end; period++ {
+		c.verifySignedHeader(tc, float64(period)+0.5, true)
+	}
+	c.verifySignedHeader(tc, float64(end)+1.5, false)
+}
+
+func newTestGenesis() types.ChainConfig {
+	var config types.ChainConfig
+	rand.Read(config.GenesisValidatorsRoot[:])
+	return config
+}
+
+func newTestForks(config types.ChainConfig, forks types.Forks) types.ChainConfig {
+	for _, fork := range forks {
+		config.AddFork(fork.Name, fork.Epoch, fork.Version)
+	}
+	return config
+}
+
+func newTestCommitteeChain(parent *testCommitteeChain, config types.ChainConfig, newCommittees bool, begin, end int, signerCount int, finalizedHeader bool) *testCommitteeChain {
+	tc := &testCommitteeChain{
+		config: config,
+	}
+	if parent != nil {
+		tc.periods = make([]testPeriod, len(parent.periods))
+		copy(tc.periods, parent.periods)
+	}
+	if newCommittees {
+		if begin == 0 {
+			tc.fillCommittees(begin, end+1)
+		} else {
+			tc.fillCommittees(begin+1, end+1)
+		}
+	}
+	tc.fillUpdates(begin, end, signerCount, finalizedHeader)
+	return tc
+}
+
+type testPeriod struct {
+	committee *types.SerializedSyncCommittee
+	update    *types.LightClientUpdate
+}
+
+type testCommitteeChain struct {
+	periods []testPeriod
+	config  types.ChainConfig
+}
+
+func (tc *testCommitteeChain) fillCommittees(begin, end int) {
+	if len(tc.periods) <= end {
+		tc.periods = append(tc.periods, make([]testPeriod, end+1-len(tc.periods))...)
+	}
+	for i := begin; i <= end; i++ {
+		tc.periods[i].committee = GenerateTestCommittee()
+	}
+}
+
+func (tc *testCommitteeChain) fillUpdates(begin, end int, signerCount int, finalizedHeader bool) {
+	for i := begin; i <= end; i++ {
+		tc.periods[i].update = GenerateTestUpdate(&tc.config, uint64(i), tc.periods[i].committee, tc.periods[i+1].committee, signerCount, finalizedHeader)
+	}
+}

beacon/light/head_tracker.go

@@ -0,0 +1,161 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package light
+
+import (
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// HeadTracker keeps track of the latest validated head and the "prefetch" head
+// which is the (not necessarily validated) head announced by the majority of
+// servers.
+type HeadTracker struct {
+	lock                sync.RWMutex
+	committeeChain      *CommitteeChain
+	minSignerCount      int
+	optimisticUpdate    types.OptimisticUpdate
+	hasOptimisticUpdate bool
+	finalityUpdate      types.FinalityUpdate
+	hasFinalityUpdate   bool
+	prefetchHead        types.HeadInfo
+	changeCounter       uint64
+}
+
+// NewHeadTracker creates a new HeadTracker.
+func NewHeadTracker(committeeChain *CommitteeChain, minSignerCount int) *HeadTracker {
+	return &HeadTracker{
+		committeeChain: committeeChain,
+		minSignerCount: minSignerCount,
+	}
+}
+
+// ValidatedOptimistic returns the latest validated optimistic update.
+func (h *HeadTracker) ValidatedOptimistic() (types.OptimisticUpdate, bool) {
+	h.lock.RLock()
+	defer h.lock.RUnlock()
+
+	return h.optimisticUpdate, h.hasOptimisticUpdate
+}
+
+// ValidatedFinality returns the latest validated finality update.
+func (h *HeadTracker) ValidatedFinality() (types.FinalityUpdate, bool) {
+	h.lock.RLock()
+	defer h.lock.RUnlock()
+
+	return h.finalityUpdate, h.hasFinalityUpdate
+}
+
+// ValidateOptimistic validates the given optimistic update. If the update is
+// successfully validated and it is better than the old validated update (higher
+// slot or same slot and more signers) then ValidatedOptimistic is updated.
+// The boolean return flag signals if ValidatedOptimistic has been changed.
+func (h *HeadTracker) ValidateOptimistic(update types.OptimisticUpdate) (bool, error) {
+	h.lock.Lock()
+	defer h.lock.Unlock()
+
+	if err := update.Validate(); err != nil {
+		return false, err
+	}
+	replace, err := h.validate(update.SignedHeader(), h.optimisticUpdate.SignedHeader())
+	if replace {
+		h.optimisticUpdate, h.hasOptimisticUpdate = update, true
+		h.changeCounter++
+	}
+	return replace, err
+}
+
+// ValidateFinality validates the given finality update. If the update is
+// successfully validated and it is better than the old validated update (higher
+// slot or same slot and more signers) then ValidatedFinality is updated.
+// The boolean return flag signals if ValidatedFinality has been changed.
+func (h *HeadTracker) ValidateFinality(update types.FinalityUpdate) (bool, error) {
+	h.lock.Lock()
+	defer h.lock.Unlock()
+
+	if err := update.Validate(); err != nil {
+		return false, err
+	}
+	replace, err := h.validate(update.SignedHeader(), h.finalityUpdate.SignedHeader())
+	if replace {
+		h.finalityUpdate, h.hasFinalityUpdate = update, true
+		h.changeCounter++
+	}
+	return replace, err
+}
+
+func (h *HeadTracker) validate(head, oldHead types.SignedHeader) (bool, error) {
+	signerCount := head.Signature.SignerCount()
+	if signerCount < h.minSignerCount {
+		return false, errors.New("low signer count")
+	}
+	if head.Header.Slot < oldHead.Header.Slot || (head.Header.Slot == oldHead.Header.Slot && signerCount <= oldHead.Signature.SignerCount()) {
+		return false, nil
+	}
+	sigOk, age, err := h.committeeChain.VerifySignedHeader(head)
+	if err != nil {
+		return false, err
+	}
+	if age < 0 {
+		log.Warn("Future signed head received", "age", age)
+	}
+	if age > time.Minute*2 {
+		log.Warn("Old signed head received", "age", age)
+	}
+	if !sigOk {
+		return false, errors.New("invalid header signature")
+	}
+	return true, nil
+}
+
+// PrefetchHead returns the latest known prefetch head's head info.
+// This head can be used to start fetching related data hoping that it will be
+// validated soon.
+// Note that the prefetch head cannot be validated cryptographically so it should
+// only be used as a performance optimization hint.
+func (h *HeadTracker) PrefetchHead() types.HeadInfo {
+	h.lock.RLock()
+	defer h.lock.RUnlock()
+
+	return h.prefetchHead
+}
+
+// SetPrefetchHead sets the prefetch head info.
+// Note that HeadTracker does not verify the prefetch head, just acts as a thread
+// safe bulletin board.
+func (h *HeadTracker) SetPrefetchHead(head types.HeadInfo) {
+	h.lock.Lock()
+	defer h.lock.Unlock()
+
+	if head == h.prefetchHead {
+		return
+	}
+	h.prefetchHead = head
+	h.changeCounter++
+}
+
+// ChangeCounter implements request.targetData
+func (h *HeadTracker) ChangeCounter() uint64 {
+	h.lock.RLock()
+	defer h.lock.RUnlock()
+
+	return h.changeCounter
+}

beacon/light/range.go

@@ -0,0 +1,78 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package light
+
+// periodRange represents a (possibly zero-length) range of integers (sync periods).
+type periodRange struct {
+	Start, End uint64
+}
+
+// isEmpty returns true if the length of the range is zero.
+func (a periodRange) isEmpty() bool {
+	return a.End == a.Start
+}
+
+// contains returns true if the range includes the given period.
+func (a periodRange) contains(period uint64) bool {
+	return period >= a.Start && period < a.End
+}
+
+// canExpand returns true if the range includes or can be expanded with the given
+// period (either the range is empty or the given period is inside, right before or
+// right after the range).
+func (a periodRange) canExpand(period uint64) bool {
+	return a.isEmpty() || (period+1 >= a.Start && period <= a.End)
+}
+
+// expand expands the range with the given period.
+// This method assumes that canExpand returned true: otherwise this is a no-op.
+func (a *periodRange) expand(period uint64) {
+	if a.isEmpty() {
+		a.Start, a.End = period, period+1
+		return
+	}
+	if a.Start == period+1 {
+		a.Start--
+	}
+	if a.End == period {
+		a.End++
+	}
+}
+
+// split splits the range into two ranges. The 'fromPeriod' will be the first
+// element in the second range (if present).
+// The original range is unchanged by this operation
+func (a *periodRange) split(fromPeriod uint64) (periodRange, periodRange) {
+	if fromPeriod <= a.Start {
+		// First range empty, everything in second range,
+		return periodRange{}, *a
+	}
+	if fromPeriod >= a.End {
+		// Second range empty, everything in first range,
+		return *a, periodRange{}
+	}
+	x := periodRange{a.Start, fromPeriod}
+	y := periodRange{fromPeriod, a.End}
+	return x, y
+}
+
+// each invokes the supplied function fn once per period in range
+func (a *periodRange) each(fn func(uint64)) {
+	for p := a.Start; p < a.End; p++ {
+		fn(p)
+	}
+}

beacon/light/request/scheduler.go

@@ -0,0 +1,403 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package request
+
+import (
+	"sync"
+
+	"github.com/ethereum/go-ethereum/log"
+)
+
+// Module represents a mechanism which is typically responsible for downloading
+// and updating a passive data structure. It does not directly interact with the
+// servers. It can start requests using the Requester interface, maintain its
+// internal state by receiving and processing Events and update its target data
+// structure based on the obtained data.
+// It is the Scheduler's responsibility to feed events to the modules, call
+// Process as long as there might be something to process and then generate request
+// candidates using MakeRequest and start the best possible requests.
+// Modules are called by Scheduler whenever a global trigger is fired. All events
+// fire the trigger. Changing a target data structure also triggers a next
+// processing round as it could make further actions possible either by the same
+// or another Module.
+type Module interface {
+	// Process is a non-blocking function responsible for starting requests,
+	// processing events and updating the target data structures(s) and the
+	// internal state of the module. Module state typically consists of information
+	// about pending requests and registered servers.
+	// Process is always called after an event is received or after a target data
+	// structure has been changed.
+	//
+	// Note: Process functions of different modules are never called concurrently;
+	// they are called by Scheduler in the same order of priority as they were
+	// registered in.
+	Process(Requester, []Event)
+}
+
+// Requester allows Modules to obtain the list of momentarily available servers,
+// start new requests and report server failure when a response has been proven
+// to be invalid in the processing phase.
+// Note that all Requester functions should be safe to call from Module.Process.
+type Requester interface {
+	CanSendTo() []Server
+	Send(Server, Request) ID
+	Fail(Server, string)
+}
+
+// Scheduler is a modular network data retrieval framework that coordinates multiple
+// servers and retrieval mechanisms (modules). It implements a trigger mechanism
+// that calls the Process function of registered modules whenever either the state
+// of existing data structures or events coming from registered servers could
+// allow new operations.
+type Scheduler struct {
+	lock    sync.Mutex
+	modules []Module // first has the highest priority
+	names   map[Module]string
+	servers map[server]struct{}
+	targets map[targetData]uint64
+
+	requesterLock sync.RWMutex
+	serverOrder   []server
+	pending       map[ServerAndID]pendingRequest
+
+	// eventLock guards access to the events list. Note that eventLock can be
+	// locked either while lock is locked or unlocked but lock cannot be locked
+	// while eventLock is locked.
+	eventLock sync.Mutex
+	events    []Event
+	stopCh    chan chan struct{}
+
+	triggerCh chan struct{} // restarts waiting sync loop
+	// if trigger has already been fired then send to testWaitCh blocks until
+	// the triggered processing round is finished
+	testWaitCh chan struct{}
+}
+
+type (
+	// Server identifies a server without allowing any direct interaction.
+	// Note: server interface is used by Scheduler and Tracker but not used by
+	// the modules that do not interact with them directly.
+	// In order to make module testing easier, Server interface is used in
+	// events and modules.
+	Server interface {
+		Name() string
+	}
+	Request     any
+	Response    any
+	ID          uint64
+	ServerAndID struct {
+		Server Server
+		ID     ID
+	}
+)
+
+// targetData represents a registered target data structure that increases its
+// ChangeCounter whenever it has been changed.
+type targetData interface {
+	ChangeCounter() uint64
+}
+
+// pendingRequest keeps track of sent and not yet finalized requests and their
+// sender modules.
+type pendingRequest struct {
+	request Request
+	module  Module
+}
+
+// NewScheduler creates a new Scheduler.
+func NewScheduler() *Scheduler {
+	s := &Scheduler{
+		servers: make(map[server]struct{}),
+		names:   make(map[Module]string),
+		pending: make(map[ServerAndID]pendingRequest),
+		targets: make(map[targetData]uint64),
+		stopCh:  make(chan chan struct{}),
+		// Note: testWaitCh should not have capacity in order to ensure
+		// that after a trigger happens testWaitCh will block until the resulting
+		// processing round has been finished
+		triggerCh:  make(chan struct{}, 1),
+		testWaitCh: make(chan struct{}),
+	}
+	return s
+}
+
+// RegisterTarget registers a target data structure, ensuring that any changes
+// made to it trigger a new round of Module.Process calls, giving a chance to
+// modules to react to the changes.
+func (s *Scheduler) RegisterTarget(t targetData) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.targets[t] = 0
+}
+
+// RegisterModule registers a module. Should be called before starting the scheduler.
+// In each processing round the order of module processing depends on the order of
+// registration.
+func (s *Scheduler) RegisterModule(m Module, name string) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.modules = append(s.modules, m)
+	s.names[m] = name
+}
+
+// RegisterServer registers a new server.
+func (s *Scheduler) RegisterServer(server server) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.addEvent(Event{Type: EvRegistered, Server: server})
+	server.subscribe(func(event Event) {
+		event.Server = server
+		s.addEvent(event)
+	})
+}
+
+// UnregisterServer removes a registered server.
+func (s *Scheduler) UnregisterServer(server server) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	server.unsubscribe()
+	s.addEvent(Event{Type: EvUnregistered, Server: server})
+}
+
+// Start starts the scheduler. It should be called after registering all modules
+// and before registering any servers.
+func (s *Scheduler) Start() {
+	go s.syncLoop()
+}
+
+// Stop stops the scheduler.
+func (s *Scheduler) Stop() {
+	stop := make(chan struct{})
+	s.stopCh <- stop
+	<-stop
+	s.lock.Lock()
+	for server := range s.servers {
+		server.unsubscribe()
+	}
+	s.servers = nil
+	s.lock.Unlock()
+}
+
+// syncLoop is the main event loop responsible for event/data processing and
+// sending new requests.
+// A round of processing starts whenever the global trigger is fired. Triggers
+// fired during a processing round ensure that there is going to be a next round.
+func (s *Scheduler) syncLoop() {
+	for {
+		s.lock.Lock()
+		s.processRound()
+		s.lock.Unlock()
+	loop:
+		for {
+			select {
+			case stop := <-s.stopCh:
+				close(stop)
+				return
+			case <-s.triggerCh:
+				break loop
+			case <-s.testWaitCh:
+			}
+		}
+	}
+}
+
+// targetChanged returns true if a registered target data structure has been
+// changed since the last call to this function.
+func (s *Scheduler) targetChanged() (changed bool) {
+	for target, counter := range s.targets {
+		if newCounter := target.ChangeCounter(); newCounter != counter {
+			s.targets[target] = newCounter
+			changed = true
+		}
+	}
+	return
+}
+
+// processRound runs an entire processing round. It calls the Process functions
+// of all modules, passing all relevant events and repeating Process calls as
+// long as any changes have been made to the registered target data structures.
+// Once all events have been processed and a stable state has been achieved,
+// requests are generated and sent if necessary and possible.
+func (s *Scheduler) processRound() {
+	for {
+		log.Trace("Processing modules")
+		filteredEvents := s.filterEvents()
+		for _, module := range s.modules {
+			log.Trace("Processing module", "name", s.names[module], "events", len(filteredEvents[module]))
+			module.Process(requester{s, module}, filteredEvents[module])
+		}
+		if !s.targetChanged() {
+			break
+		}
+	}
+}
+
+// Trigger starts a new processing round. If fired during processing, it ensures
+// another full round of processing all modules.
+func (s *Scheduler) Trigger() {
+	select {
+	case s.triggerCh <- struct{}{}:
+	default:
+	}
+}
+
+// addEvent adds an event to be processed in the next round. Note that it can be
+// called regardless of the state of the lock mutex, making it safe for use in
+// the server event callback.
+func (s *Scheduler) addEvent(event Event) {
+	s.eventLock.Lock()
+	s.events = append(s.events, event)
+	s.eventLock.Unlock()
+	s.Trigger()
+}
+
+// filterEvent sorts each Event either as a request event or a server event,
+// depending on its type. Request events are also sorted in a map based on the
+// module that originally initiated the request. It also ensures that no events
+// related to a server are returned before EvRegistered or after EvUnregistered.
+// In case of an EvUnregistered server event it also closes all pending requests
+// to the given server by adding a failed request event (EvFail), ensuring that
+// all requests get finalized and thereby allowing the module logic to be safe
+// and simple.
+func (s *Scheduler) filterEvents() map[Module][]Event {
+	s.eventLock.Lock()
+	events := s.events
+	s.events = nil
+	s.eventLock.Unlock()
+
+	s.requesterLock.Lock()
+	defer s.requesterLock.Unlock()
+
+	filteredEvents := make(map[Module][]Event)
+	for _, event := range events {
+		server := event.Server.(server)
+		if _, ok := s.servers[server]; !ok && event.Type != EvRegistered {
+			continue // before EvRegister or after EvUnregister, discard
+		}
+
+		if event.IsRequestEvent() {
+			sid, _, _ := event.RequestInfo()
+			pending, ok := s.pending[sid]
+			if !ok {
+				continue // request already closed, ignore further events
+			}
+			if event.Type == EvResponse || event.Type == EvFail {
+				delete(s.pending, sid) // final event, close pending request
+			}
+			filteredEvents[pending.module] = append(filteredEvents[pending.module], event)
+		} else {
+			switch event.Type {
+			case EvRegistered:
+				s.servers[server] = struct{}{}
+				s.serverOrder = append(s.serverOrder, nil)
+				copy(s.serverOrder[1:], s.serverOrder[:len(s.serverOrder)-1])
+				s.serverOrder[0] = server
+			case EvUnregistered:
+				s.closePending(event.Server, filteredEvents)
+				delete(s.servers, server)
+				for i, srv := range s.serverOrder {
+					if srv == server {
+						copy(s.serverOrder[i:len(s.serverOrder)-1], s.serverOrder[i+1:])
+						s.serverOrder = s.serverOrder[:len(s.serverOrder)-1]
+						break
+					}
+				}
+			}
+			for _, module := range s.modules {
+				filteredEvents[module] = append(filteredEvents[module], event)
+			}
+		}
+	}
+	return filteredEvents
+}
+
+// closePending closes all pending requests to the given server and adds an EvFail
+// event to properly finalize them
+func (s *Scheduler) closePending(server Server, filteredEvents map[Module][]Event) {
+	for sid, pending := range s.pending {
+		if sid.Server == server {
+			filteredEvents[pending.module] = append(filteredEvents[pending.module], Event{
+				Type:   EvFail,
+				Server: server,
+				Data: RequestResponse{
+					ID:      sid.ID,
+					Request: pending.request,
+				},
+			})
+			delete(s.pending, sid)
+		}
+	}
+}
+
+// requester implements Requester. Note that while requester basically wraps
+// Scheduler (with the added information of the currently processed Module), all
+// functions are safe to call from Module.Process which is running while
+// the Scheduler.lock mutex is held.
+type requester struct {
+	*Scheduler
+	module Module
+}
+
+// CanSendTo returns the list of currently available servers. It also returns
+// them in an order of least to most recently used, ensuring a round-robin usage
+// of suitable servers if the module always chooses the first suitable one.
+func (s requester) CanSendTo() []Server {
+	s.requesterLock.RLock()
+	defer s.requesterLock.RUnlock()
+
+	list := make([]Server, 0, len(s.serverOrder))
+	for _, server := range s.serverOrder {
+		if server.canRequestNow() {
+			list = append(list, server)
+		}
+	}
+	return list
+}
+
+// Send sends a request and adds an entry to Scheduler.pending map, ensuring that
+// related request events will be delivered to the sender Module.
+func (s requester) Send(srv Server, req Request) ID {
+	s.requesterLock.Lock()
+	defer s.requesterLock.Unlock()
+
+	server := srv.(server)
+	id := server.sendRequest(req)
+	sid := ServerAndID{Server: srv, ID: id}
+	s.pending[sid] = pendingRequest{request: req, module: s.module}
+	for i, ss := range s.serverOrder {
+		if ss == server {
+			copy(s.serverOrder[i:len(s.serverOrder)-1], s.serverOrder[i+1:])
+			s.serverOrder[len(s.serverOrder)-1] = server
+			return id
+		}
+	}
+	log.Error("Target server not found in ordered list of registered servers")
+	return id
+}
+
+// Fail should be called when a server delivers invalid or useless information.
+// Calling Fail disables the given server for a period that is initially short
+// but is exponentially growing if it happens frequently. This results in a
+// somewhat fault tolerant operation that avoids hammering servers with requests
+// that they cannot serve but still gives them a chance periodically.
+func (s requester) Fail(srv Server, desc string) {
+	srv.(server).fail(desc)
+}

beacon/light/request/scheduler_test.go

@@ -0,0 +1,126 @@
+package request
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestEventFilter(t *testing.T) {
+	s := NewScheduler()
+	module1 := &testModule{name: "module1"}
+	module2 := &testModule{name: "module2"}
+	s.RegisterModule(module1, "module1")
+	s.RegisterModule(module2, "module2")
+	s.Start()
+	// startup process round without events
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, nil)
+	module2.expProcess(t, nil)
+	srv := &testServer{}
+	// register server; both modules should receive server event
+	s.RegisterServer(srv)
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, []Event{
+		{Type: EvRegistered, Server: srv},
+	})
+	module2.expProcess(t, []Event{
+		{Type: EvRegistered, Server: srv},
+	})
+	// let module1 send a request
+	srv.canRequest = 1
+	module1.sendReq = testRequest
+	s.Trigger()
+	// in first triggered round module1 sends the request, no events yet
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, nil)
+	module2.expProcess(t, nil)
+	// server emits EvTimeout; only module1 should receive it
+	srv.eventCb(Event{Type: EvTimeout, Data: RequestResponse{ID: 1, Request: testRequest}})
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, []Event{
+		{Type: EvTimeout, Server: srv, Data: RequestResponse{ID: 1, Request: testRequest}},
+	})
+	module2.expProcess(t, nil)
+	// unregister server; both modules should receive server event
+	s.UnregisterServer(srv)
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, []Event{
+		// module1 should also receive EvFail on its pending request
+		{Type: EvFail, Server: srv, Data: RequestResponse{ID: 1, Request: testRequest}},
+		{Type: EvUnregistered, Server: srv},
+	})
+	module2.expProcess(t, []Event{
+		{Type: EvUnregistered, Server: srv},
+	})
+	// response after server unregistered; should be discarded
+	srv.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 1, Request: testRequest, Response: testResponse}})
+	s.testWaitCh <- struct{}{}
+	module1.expProcess(t, nil)
+	module2.expProcess(t, nil)
+	// no more process rounds expected; shut down
+	s.testWaitCh <- struct{}{}
+	module1.expNoMoreProcess(t)
+	module2.expNoMoreProcess(t)
+	s.Stop()
+}
+
+type testServer struct {
+	eventCb    func(Event)
+	lastID     ID
+	canRequest int
+}
+
+func (s *testServer) Name() string {
+	return ""
+}
+
+func (s *testServer) subscribe(eventCb func(Event)) {
+	s.eventCb = eventCb
+}
+
+func (s *testServer) canRequestNow() bool {
+	return s.canRequest > 0
+}
+
+func (s *testServer) sendRequest(req Request) ID {
+	s.canRequest--
+	s.lastID++
+	return s.lastID
+}
+
+func (s *testServer) fail(string)  {}
+func (s *testServer) unsubscribe() {}
+
+type testModule struct {
+	name      string
+	processed [][]Event
+	sendReq   Request
+}
+
+func (m *testModule) Process(requester Requester, events []Event) {
+	m.processed = append(m.processed, events)
+	if m.sendReq != nil {
+		if cs := requester.CanSendTo(); len(cs) > 0 {
+			requester.Send(cs[0], m.sendReq)
+		}
+	}
+}
+
+func (m *testModule) expProcess(t *testing.T, expEvents []Event) {
+	if len(m.processed) == 0 {
+		t.Errorf("Missing call to %s.Process", m.name)
+		return
+	}
+	events := m.processed[0]
+	m.processed = m.processed[1:]
+	if !reflect.DeepEqual(events, expEvents) {
+		t.Errorf("Call to %s.Process with wrong events (expected %v, got %v)", m.name, expEvents, events)
+	}
+}
+
+func (m *testModule) expNoMoreProcess(t *testing.T) {
+	for len(m.processed) > 0 {
+		t.Errorf("Unexpected call to %s.Process with events %v", m.name, m.processed[0])
+		m.processed = m.processed[1:]
+	}
+}

beacon/light/request/server.go

@@ -0,0 +1,451 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package request
+
+import (
+	"math"
+	"sync"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common/mclock"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+var (
+	// request events
+	EvResponse = &EventType{Name: "response", requestEvent: true} // data: RequestResponse; sent by requestServer
+	EvFail     = &EventType{Name: "fail", requestEvent: true}     // data: RequestResponse; sent by requestServer
+	EvTimeout  = &EventType{Name: "timeout", requestEvent: true}  // data: RequestResponse; sent by serverWithTimeout
+	// server events
+	EvRegistered      = &EventType{Name: "registered"}      // data: nil; sent by Scheduler
+	EvUnregistered    = &EventType{Name: "unregistered"}    // data: nil; sent by Scheduler
+	EvCanRequestAgain = &EventType{Name: "canRequestAgain"} // data: nil; sent by serverWithLimits
+)
+
+const (
+	softRequestTimeout = time.Second      // allow resending request to a different server but do not cancel yet
+	hardRequestTimeout = time.Second * 10 // cancel request
+)
+
+const (
+	// serverWithLimits parameters
+	parallelAdjustUp     = 0.1                    // adjust parallelLimit up in case of success under full load
+	parallelAdjustDown   = 1                      // adjust parallelLimit down in case of timeout/failure
+	minParallelLimit     = 1                      // parallelLimit lower bound
+	defaultParallelLimit = 3                      // parallelLimit initial value
+	minFailureDelay      = time.Millisecond * 100 // minimum disable time in case of request failure
+	maxFailureDelay      = time.Minute            // maximum disable time in case of request failure
+	maxServerEventBuffer = 5                      // server event allowance buffer limit
+	maxServerEventRate   = time.Second            // server event allowance buffer recharge rate
+)
+
+// requestServer can send requests in a non-blocking way and feed back events
+// through the event callback. After each request it should send back either
+// EvResponse or EvFail. Additionally, it may also send application-defined
+// events that the Modules can interpret.
+type requestServer interface {
+	Name() string
+	Subscribe(eventCallback func(Event))
+	SendRequest(ID, Request)
+	Unsubscribe()
+}
+
+// server is implemented by a requestServer wrapped into serverWithTimeout and
+// serverWithLimits and is used by Scheduler.
+// In addition to requestServer functionality, server can also handle timeouts,
+// limit the number of parallel in-flight requests and temporarily disable
+// new requests based on timeouts and response failures.
+type server interface {
+	Server
+	subscribe(eventCallback func(Event))
+	canRequestNow() bool
+	sendRequest(Request) ID
+	fail(string)
+	unsubscribe()
+}
+
+// NewServer wraps a requestServer and returns a server
+func NewServer(rs requestServer, clock mclock.Clock) server {
+	s := &serverWithLimits{}
+	s.parent = rs
+	s.serverWithTimeout.init(clock)
+	s.init()
+	return s
+}
+
+// EventType identifies an event type, either related to a request or the server
+// in general. Server events can also be externally defined.
+type EventType struct {
+	Name         string
+	requestEvent bool // all request events are pre-defined in request package
+}
+
+// Event describes an event where the type of Data depends on Type.
+// Server field is not required when sent through the event callback; it is filled
+// out when processed by the Scheduler. Note that the Scheduler can also create
+// and send events (EvRegistered, EvUnregistered) directly.
+type Event struct {
+	Type   *EventType
+	Server Server // filled by Scheduler
+	Data   any
+}
+
+// IsRequestEvent returns true if the event is a request event
+func (e *Event) IsRequestEvent() bool {
+	return e.Type.requestEvent
+}
+
+// RequestInfo assumes that the event is a request event and returns its contents
+// in a convenient form.
+func (e *Event) RequestInfo() (ServerAndID, Request, Response) {
+	data := e.Data.(RequestResponse)
+	return ServerAndID{Server: e.Server, ID: data.ID}, data.Request, data.Response
+}
+
+// RequestResponse is the Data type of request events.
+type RequestResponse struct {
+	ID       ID
+	Request  Request
+	Response Response
+}
+
+// serverWithTimeout wraps a requestServer and introduces timeouts.
+// The request's lifecycle is concluded if EvResponse or EvFail emitted by the
+// parent requestServer. If this does not happen until softRequestTimeout then
+// EvTimeout is emitted, after which the final EvResponse or EvFail is still
+// guaranteed to follow.
+// If the parent fails to send this final event for hardRequestTimeout then
+// serverWithTimeout emits EvFail and discards any further events from the
+// parent related to the given request.
+type serverWithTimeout struct {
+	parent       requestServer
+	lock         sync.Mutex
+	clock        mclock.Clock
+	childEventCb func(event Event)
+	timeouts     map[ID]mclock.Timer
+	lastID       ID
+}
+
+// Name implements request.Server
+func (s *serverWithTimeout) Name() string {
+	return s.parent.Name()
+}
+
+// init initializes serverWithTimeout
+func (s *serverWithTimeout) init(clock mclock.Clock) {
+	s.clock = clock
+	s.timeouts = make(map[ID]mclock.Timer)
+}
+
+// subscribe subscribes to events which include parent (requestServer) events
+// plus EvTimeout.
+func (s *serverWithTimeout) subscribe(eventCallback func(event Event)) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.childEventCb = eventCallback
+	s.parent.Subscribe(s.eventCallback)
+}
+
+// sendRequest generated a new request ID, emits EvRequest, sets up the timeout
+// timer, then sends the request through the parent (requestServer).
+func (s *serverWithTimeout) sendRequest(request Request) (reqId ID) {
+	s.lock.Lock()
+	s.lastID++
+	id := s.lastID
+	s.startTimeout(RequestResponse{ID: id, Request: request})
+	s.lock.Unlock()
+	s.parent.SendRequest(id, request)
+	return id
+}
+
+// eventCallback is called by parent (requestServer) event subscription.
+func (s *serverWithTimeout) eventCallback(event Event) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	switch event.Type {
+	case EvResponse, EvFail:
+		id := event.Data.(RequestResponse).ID
+		if timer, ok := s.timeouts[id]; ok {
+			// Note: if stopping the timer is unsuccessful then the resulting AfterFunc
+			// call will just do nothing
+			timer.Stop()
+			delete(s.timeouts, id)
+			if s.childEventCb != nil {
+				s.childEventCb(event)
+			}
+		}
+	default:
+		if s.childEventCb != nil {
+			s.childEventCb(event)
+		}
+	}
+}
+
+// startTimeout starts a timeout timer for the given request.
+func (s *serverWithTimeout) startTimeout(reqData RequestResponse) {
+	id := reqData.ID
+	s.timeouts[id] = s.clock.AfterFunc(softRequestTimeout, func() {
+		s.lock.Lock()
+		if _, ok := s.timeouts[id]; !ok {
+			s.lock.Unlock()
+			return
+		}
+		s.timeouts[id] = s.clock.AfterFunc(hardRequestTimeout-softRequestTimeout, func() {
+			s.lock.Lock()
+			if _, ok := s.timeouts[id]; !ok {
+				s.lock.Unlock()
+				return
+			}
+			delete(s.timeouts, id)
+			childEventCb := s.childEventCb
+			s.lock.Unlock()
+			if childEventCb != nil {
+				childEventCb(Event{Type: EvFail, Data: reqData})
+			}
+		})
+		childEventCb := s.childEventCb
+		s.lock.Unlock()
+		if childEventCb != nil {
+			childEventCb(Event{Type: EvTimeout, Data: reqData})
+		}
+	})
+}
+
+// unsubscribe stops all goroutines associated with the server.
+func (s *serverWithTimeout) unsubscribe() {
+	s.lock.Lock()
+	for _, timer := range s.timeouts {
+		if timer != nil {
+			timer.Stop()
+		}
+	}
+	s.lock.Unlock()
+	s.parent.Unsubscribe()
+}
+
+// serverWithLimits wraps serverWithTimeout and implements server. It limits the
+// number of parallel in-flight requests and prevents sending new requests when a
+// pending one has already timed out. Server events are also rate limited.
+// It also implements a failure delay mechanism that adds an exponentially growing
+// delay each time a request fails (wrong answer or hard timeout). This makes the
+// syncing mechanism less brittle as temporary failures of the server might happen
+// sometimes, but still avoids hammering a non-functional server with requests.
+type serverWithLimits struct {
+	serverWithTimeout
+	lock                       sync.Mutex
+	childEventCb               func(event Event)
+	softTimeouts               map[ID]struct{}
+	pendingCount, timeoutCount int
+	parallelLimit              float32
+	sendEvent                  bool
+	delayTimer                 mclock.Timer
+	delayCounter               int
+	failureDelayEnd            mclock.AbsTime
+	failureDelay               float64
+	serverEventBuffer          int
+	eventBufferUpdated         mclock.AbsTime
+}
+
+// init initializes serverWithLimits
+func (s *serverWithLimits) init() {
+	s.softTimeouts = make(map[ID]struct{})
+	s.parallelLimit = defaultParallelLimit
+	s.serverEventBuffer = maxServerEventBuffer
+}
+
+// subscribe subscribes to events which include parent (serverWithTimeout) events
+// plus EvCanRequestAgain.
+func (s *serverWithLimits) subscribe(eventCallback func(event Event)) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.childEventCb = eventCallback
+	s.serverWithTimeout.subscribe(s.eventCallback)
+}
+
+// eventCallback is called by parent (serverWithTimeout) event subscription.
+func (s *serverWithLimits) eventCallback(event Event) {
+	s.lock.Lock()
+	var sendCanRequestAgain bool
+	passEvent := true
+	switch event.Type {
+	case EvTimeout:
+		id := event.Data.(RequestResponse).ID
+		s.softTimeouts[id] = struct{}{}
+		s.timeoutCount++
+		s.parallelLimit -= parallelAdjustDown
+		if s.parallelLimit < minParallelLimit {
+			s.parallelLimit = minParallelLimit
+		}
+		log.Debug("Server timeout", "count", s.timeoutCount, "parallelLimit", s.parallelLimit)
+	case EvResponse, EvFail:
+		id := event.Data.(RequestResponse).ID
+		if _, ok := s.softTimeouts[id]; ok {
+			delete(s.softTimeouts, id)
+			s.timeoutCount--
+			log.Debug("Server timeout finalized", "count", s.timeoutCount, "parallelLimit", s.parallelLimit)
+		}
+		if event.Type == EvResponse && s.pendingCount >= int(s.parallelLimit) {
+			s.parallelLimit += parallelAdjustUp
+		}
+		s.pendingCount--
+		if s.canRequest() {
+			sendCanRequestAgain = s.sendEvent
+			s.sendEvent = false
+		}
+		if event.Type == EvFail {
+			s.failLocked("failed request")
+		}
+	default:
+		// server event; check rate limit
+		if s.serverEventBuffer < maxServerEventBuffer {
+			now := s.clock.Now()
+			sinceUpdate := time.Duration(now - s.eventBufferUpdated)
+			if sinceUpdate >= maxServerEventRate*time.Duration(maxServerEventBuffer-s.serverEventBuffer) {
+				s.serverEventBuffer = maxServerEventBuffer
+				s.eventBufferUpdated = now
+			} else {
+				addBuffer := int(sinceUpdate / maxServerEventRate)
+				s.serverEventBuffer += addBuffer
+				s.eventBufferUpdated += mclock.AbsTime(maxServerEventRate * time.Duration(addBuffer))
+			}
+		}
+		if s.serverEventBuffer > 0 {
+			s.serverEventBuffer--
+		} else {
+			passEvent = false
+		}
+	}
+	childEventCb := s.childEventCb
+	s.lock.Unlock()
+	if passEvent && childEventCb != nil {
+		childEventCb(event)
+	}
+	if sendCanRequestAgain && childEventCb != nil {
+		childEventCb(Event{Type: EvCanRequestAgain})
+	}
+}
+
+// sendRequest sends a request through the parent (serverWithTimeout).
+func (s *serverWithLimits) sendRequest(request Request) (reqId ID) {
+	s.lock.Lock()
+	s.pendingCount++
+	s.lock.Unlock()
+	return s.serverWithTimeout.sendRequest(request)
+}
+
+// unsubscribe stops all goroutines associated with the server.
+func (s *serverWithLimits) unsubscribe() {
+	s.lock.Lock()
+	if s.delayTimer != nil {
+		s.delayTimer.Stop()
+		s.delayTimer = nil
+	}
+	s.childEventCb = nil
+	s.lock.Unlock()
+	s.serverWithTimeout.unsubscribe()
+}
+
+// canRequest checks whether a new request can be started.
+func (s *serverWithLimits) canRequest() bool {
+	if s.delayTimer != nil || s.pendingCount >= int(s.parallelLimit) || s.timeoutCount > 0 {
+		return false
+	}
+	if s.parallelLimit < minParallelLimit {
+		s.parallelLimit = minParallelLimit
+	}
+	return true
+}
+
+// canRequestNow checks whether a new request can be started, according to the
+// current in-flight request count and parallelLimit, and also the failure delay
+// timer.
+// If it returns false then it is guaranteed that an EvCanRequestAgain will be
+// sent whenever the server becomes available for requesting again.
+func (s *serverWithLimits) canRequestNow() bool {
+	var sendCanRequestAgain bool
+	s.lock.Lock()
+	canRequest := s.canRequest()
+	if canRequest {
+		sendCanRequestAgain = s.sendEvent
+		s.sendEvent = false
+	}
+	childEventCb := s.childEventCb
+	s.lock.Unlock()
+	if sendCanRequestAgain && childEventCb != nil {
+		childEventCb(Event{Type: EvCanRequestAgain})
+	}
+	return canRequest
+}
+
+// delay sets the delay timer to the given duration, disabling new requests for
+// the given period.
+func (s *serverWithLimits) delay(delay time.Duration) {
+	if s.delayTimer != nil {
+		// Note: if stopping the timer is unsuccessful then the resulting AfterFunc
+		// call will just do nothing
+		s.delayTimer.Stop()
+		s.delayTimer = nil
+	}
+
+	s.delayCounter++
+	delayCounter := s.delayCounter
+	log.Debug("Server delay started", "length", delay)
+	s.delayTimer = s.clock.AfterFunc(delay, func() {
+		log.Debug("Server delay ended", "length", delay)
+		var sendCanRequestAgain bool
+		s.lock.Lock()
+		if s.delayTimer != nil && s.delayCounter == delayCounter { // do nothing if there is a new timer now
+			s.delayTimer = nil
+			if s.canRequest() {
+				sendCanRequestAgain = s.sendEvent
+				s.sendEvent = false
+			}
+		}
+		childEventCb := s.childEventCb
+		s.lock.Unlock()
+		if sendCanRequestAgain && childEventCb != nil {
+			childEventCb(Event{Type: EvCanRequestAgain})
+		}
+	})
+}
+
+// fail reports that a response from the server was found invalid by the processing
+// Module, disabling new requests for a dynamically adjusted time period.
+func (s *serverWithLimits) fail(desc string) {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+
+	s.failLocked(desc)
+}
+
+// failLocked calculates the dynamic failure delay and applies it.
+func (s *serverWithLimits) failLocked(desc string) {
+	log.Debug("Server error", "description", desc)
+	s.failureDelay *= 2
+	now := s.clock.Now()
+	if now > s.failureDelayEnd {
+		s.failureDelay *= math.Pow(2, -float64(now-s.failureDelayEnd)/float64(maxFailureDelay))
+	}
+	if s.failureDelay < float64(minFailureDelay) {
+		s.failureDelay = float64(minFailureDelay)
+	}
+	s.failureDelayEnd = now + mclock.AbsTime(s.failureDelay)
+	s.delay(time.Duration(s.failureDelay))
+}

beacon/light/request/server_test.go

@@ -0,0 +1,182 @@
+package request
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/common/mclock"
+)
+
+const (
+	testRequest  = "Life, the Universe, and Everything"
+	testResponse = 42
+)
+
+var testEventType = &EventType{Name: "testEvent"}
+
+func TestServerEvents(t *testing.T) {
+	rs := &testRequestServer{}
+	clock := &mclock.Simulated{}
+	srv := NewServer(rs, clock)
+	var lastEventType *EventType
+	srv.subscribe(func(event Event) { lastEventType = event.Type })
+	evTypeName := func(evType *EventType) string {
+		if evType == nil {
+			return "none"
+		}
+		return evType.Name
+	}
+	expEvent := func(expType *EventType) {
+		if lastEventType != expType {
+			t.Errorf("Wrong event type (expected %s, got %s)", evTypeName(expType), evTypeName(lastEventType))
+		}
+		lastEventType = nil
+	}
+	// user events should simply be passed through
+	rs.eventCb(Event{Type: testEventType})
+	expEvent(testEventType)
+	// send request, soft timeout, then valid response
+	srv.sendRequest(testRequest)
+	clock.WaitForTimers(1)
+	clock.Run(softRequestTimeout)
+	expEvent(EvTimeout)
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 1, Request: testRequest, Response: testResponse}})
+	expEvent(EvResponse)
+	// send request, hard timeout (response after hard timeout should be ignored)
+	srv.sendRequest(testRequest)
+	clock.WaitForTimers(1)
+	clock.Run(softRequestTimeout)
+	expEvent(EvTimeout)
+	clock.WaitForTimers(1)
+	clock.Run(hardRequestTimeout)
+	expEvent(EvFail)
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 1, Request: testRequest, Response: testResponse}})
+	expEvent(nil)
+	srv.unsubscribe()
+}
+
+func TestServerParallel(t *testing.T) {
+	rs := &testRequestServer{}
+	srv := NewServer(rs, &mclock.Simulated{})
+	srv.subscribe(func(event Event) {})
+
+	expSend := func(expSent int) {
+		var sent int
+		for sent <= expSent {
+			if !srv.canRequestNow() {
+				break
+			}
+			sent++
+			srv.sendRequest(testRequest)
+		}
+		if sent != expSent {
+			t.Errorf("Wrong number of parallel requests accepted (expected %d, got %d)", expSent, sent)
+		}
+	}
+	// max out parallel allowance
+	expSend(defaultParallelLimit)
+	// 1 answered, should accept 1 more
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 1, Request: testRequest, Response: testResponse}})
+	expSend(1)
+	// 2 answered, should accept 2 more
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 2, Request: testRequest, Response: testResponse}})
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 3, Request: testRequest, Response: testResponse}})
+	expSend(2)
+	// failed request, should decrease allowance and not accept more
+	rs.eventCb(Event{Type: EvFail, Data: RequestResponse{ID: 4, Request: testRequest}})
+	expSend(0)
+	srv.unsubscribe()
+}
+
+func TestServerFail(t *testing.T) {
+	rs := &testRequestServer{}
+	clock := &mclock.Simulated{}
+	srv := NewServer(rs, clock)
+	srv.subscribe(func(event Event) {})
+	expCanRequest := func(expCanRequest bool) {
+		if canRequest := srv.canRequestNow(); canRequest != expCanRequest {
+			t.Errorf("Wrong result for canRequestNow (expected %v, got %v)", expCanRequest, canRequest)
+		}
+	}
+	// timed out request
+	expCanRequest(true)
+	srv.sendRequest(testRequest)
+	clock.WaitForTimers(1)
+	expCanRequest(true)
+	clock.Run(softRequestTimeout)
+	expCanRequest(false) // cannot request when there is a timed out request
+	rs.eventCb(Event{Type: EvResponse, Data: RequestResponse{ID: 1, Request: testRequest, Response: testResponse}})
+	expCanRequest(true)
+	// explicit server.Fail
+	srv.fail("")
+	clock.WaitForTimers(1)
+	expCanRequest(false) // cannot request for a while after a failure
+	clock.Run(minFailureDelay)
+	expCanRequest(true)
+	// request returned with EvFail
+	srv.sendRequest(testRequest)
+	rs.eventCb(Event{Type: EvFail, Data: RequestResponse{ID: 2, Request: testRequest}})
+	clock.WaitForTimers(1)
+	expCanRequest(false) // EvFail should also start failure delay
+	clock.Run(minFailureDelay)
+	expCanRequest(false) // second failure delay is longer, should still be disabled
+	clock.Run(minFailureDelay)
+	expCanRequest(true)
+	srv.unsubscribe()
+}
+
+func TestServerEventRateLimit(t *testing.T) {
+	rs := &testRequestServer{}
+	clock := &mclock.Simulated{}
+	srv := NewServer(rs, clock)
+	var eventCount int
+	srv.subscribe(func(event Event) {
+		eventCount++
+	})
+	expEvents := func(send, expAllowed int) {
+		eventCount = 0
+		for sent := 0; sent < send; sent++ {
+			rs.eventCb(Event{Type: testEventType})
+		}
+		if eventCount != expAllowed {
+			t.Errorf("Wrong number of server events passing rate limitation (sent %d, expected %d, got %d)", send, expAllowed, eventCount)
+		}
+	}
+	expEvents(maxServerEventBuffer+5, maxServerEventBuffer)
+	clock.Run(maxServerEventRate)
+	expEvents(5, 1)
+	clock.Run(maxServerEventRate * maxServerEventBuffer * 2)
+	expEvents(maxServerEventBuffer+5, maxServerEventBuffer)
+	srv.unsubscribe()
+}
+
+func TestServerUnsubscribe(t *testing.T) {
+	rs := &testRequestServer{}
+	clock := &mclock.Simulated{}
+	srv := NewServer(rs, clock)
+	var eventCount int
+	srv.subscribe(func(event Event) {
+		eventCount++
+	})
+	eventCb := rs.eventCb
+	eventCb(Event{Type: testEventType})
+	if eventCount != 1 {
+		t.Errorf("Server event callback not called before unsubscribe")
+	}
+	srv.unsubscribe()
+	if rs.eventCb != nil {
+		t.Errorf("Server event callback not removed after unsubscribe")
+	}
+	eventCb(Event{Type: testEventType})
+	if eventCount != 1 {
+		t.Errorf("Server event callback called after unsubscribe")
+	}
+}
+
+type testRequestServer struct {
+	eventCb func(Event)
+}
+
+func (rs *testRequestServer) Name() string                  { return "" }
+func (rs *testRequestServer) Subscribe(eventCb func(Event)) { rs.eventCb = eventCb }
+func (rs *testRequestServer) SendRequest(ID, Request)       {}
+func (rs *testRequestServer) Unsubscribe()                  { rs.eventCb = nil }

beacon/light/sync/head_sync.go

@@ -0,0 +1,202 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package sync
+
+import (
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+type headTracker interface {
+	ValidateOptimistic(update types.OptimisticUpdate) (bool, error)
+	ValidateFinality(head types.FinalityUpdate) (bool, error)
+	ValidatedFinality() (types.FinalityUpdate, bool)
+	SetPrefetchHead(head types.HeadInfo)
+}
+
+// HeadSync implements request.Module; it updates the validated and prefetch
+// heads of HeadTracker based on the EvHead and EvSignedHead events coming from
+// registered servers.
+// It can also postpone the validation of the latest announced signed head
+// until the committee chain is synced up to at least the required period.
+type HeadSync struct {
+	headTracker           headTracker
+	chain                 committeeChain
+	nextSyncPeriod        uint64
+	chainInit             bool
+	unvalidatedOptimistic map[request.Server]types.OptimisticUpdate
+	unvalidatedFinality   map[request.Server]types.FinalityUpdate
+	serverHeads           map[request.Server]types.HeadInfo
+	reqFinalityEpoch      map[request.Server]uint64 // next epoch to request finality update
+	headServerCount       map[types.HeadInfo]headServerCount
+	headCounter           uint64
+	prefetchHead          types.HeadInfo
+}
+
+// headServerCount is associated with most recently seen head infos; it counts
+// the number of servers currently having the given head info as their announced
+// head and a counter signaling how recent that head is.
+// This data is used for selecting the prefetch head.
+type headServerCount struct {
+	serverCount int
+	headCounter uint64
+}
+
+// NewHeadSync creates a new HeadSync.
+func NewHeadSync(headTracker headTracker, chain committeeChain) *HeadSync {
+	s := &HeadSync{
+		headTracker:           headTracker,
+		chain:                 chain,
+		unvalidatedOptimistic: make(map[request.Server]types.OptimisticUpdate),
+		unvalidatedFinality:   make(map[request.Server]types.FinalityUpdate),
+		serverHeads:           make(map[request.Server]types.HeadInfo),
+		headServerCount:       make(map[types.HeadInfo]headServerCount),
+		reqFinalityEpoch:      make(map[request.Server]uint64),
+	}
+	return s
+}
+
+// Process implements request.Module.
+func (s *HeadSync) Process(requester request.Requester, events []request.Event) {
+	nextPeriod, chainInit := s.chain.NextSyncPeriod()
+	if nextPeriod != s.nextSyncPeriod || chainInit != s.chainInit {
+		s.nextSyncPeriod, s.chainInit = nextPeriod, chainInit
+		s.processUnvalidatedUpdates()
+	}
+
+	for _, event := range events {
+		switch event.Type {
+		case EvNewHead:
+			s.setServerHead(event.Server, event.Data.(types.HeadInfo))
+		case EvNewOptimisticUpdate:
+			update := event.Data.(types.OptimisticUpdate)
+			s.newOptimisticUpdate(event.Server, update)
+			epoch := update.Attested.Epoch()
+			if epoch < s.reqFinalityEpoch[event.Server] {
+				continue
+			}
+			if finality, ok := s.headTracker.ValidatedFinality(); ok && finality.Attested.Header.Epoch() >= epoch {
+				continue
+			}
+			requester.Send(event.Server, ReqFinality{})
+			s.reqFinalityEpoch[event.Server] = epoch + 1
+		case EvNewFinalityUpdate:
+			s.newFinalityUpdate(event.Server, event.Data.(types.FinalityUpdate))
+		case request.EvResponse:
+			_, _, resp := event.RequestInfo()
+			s.newFinalityUpdate(event.Server, resp.(types.FinalityUpdate))
+		case request.EvUnregistered:
+			s.setServerHead(event.Server, types.HeadInfo{})
+			delete(s.serverHeads, event.Server)
+			delete(s.unvalidatedOptimistic, event.Server)
+			delete(s.unvalidatedFinality, event.Server)
+		}
+	}
+}
+
+// newOptimisticUpdate handles received optimistic update; either validates it if
+// the chain is properly synced or stores it for further validation.
+func (s *HeadSync) newOptimisticUpdate(server request.Server, optimisticUpdate types.OptimisticUpdate) {
+	if !s.chainInit || types.SyncPeriod(optimisticUpdate.SignatureSlot) > s.nextSyncPeriod {
+		s.unvalidatedOptimistic[server] = optimisticUpdate
+		return
+	}
+	if _, err := s.headTracker.ValidateOptimistic(optimisticUpdate); err != nil {
+		log.Debug("Error validating optimistic update", "error", err)
+	}
+}
+
+// newFinalityUpdate handles received finality update; either validates it if
+// the chain is properly synced or stores it for further validation.
+func (s *HeadSync) newFinalityUpdate(server request.Server, finalityUpdate types.FinalityUpdate) {
+	if !s.chainInit || types.SyncPeriod(finalityUpdate.SignatureSlot) > s.nextSyncPeriod {
+		s.unvalidatedFinality[server] = finalityUpdate
+		return
+	}
+	if _, err := s.headTracker.ValidateFinality(finalityUpdate); err != nil {
+		log.Debug("Error validating finality update", "error", err)
+	}
+}
+
+// processUnvalidatedUpdates iterates the list of unvalidated updates and validates
+// those which can be validated.
+func (s *HeadSync) processUnvalidatedUpdates() {
+	if !s.chainInit {
+		return
+	}
+	for server, optimisticUpdate := range s.unvalidatedOptimistic {
+		if types.SyncPeriod(optimisticUpdate.SignatureSlot) <= s.nextSyncPeriod {
+			if _, err := s.headTracker.ValidateOptimistic(optimisticUpdate); err != nil {
+				log.Debug("Error validating deferred optimistic update", "error", err)
+			}
+			delete(s.unvalidatedOptimistic, server)
+		}
+	}
+	for server, finalityUpdate := range s.unvalidatedFinality {
+		if types.SyncPeriod(finalityUpdate.SignatureSlot) <= s.nextSyncPeriod {
+			if _, err := s.headTracker.ValidateFinality(finalityUpdate); err != nil {
+				log.Debug("Error validating deferred finality update", "error", err)
+			}
+			delete(s.unvalidatedFinality, server)
+		}
+	}
+}
+
+// setServerHead processes non-validated server head announcements and updates
+// the prefetch head if necessary.
+func (s *HeadSync) setServerHead(server request.Server, head types.HeadInfo) bool {
+	if oldHead, ok := s.serverHeads[server]; ok {
+		if head == oldHead {
+			return false
+		}
+		h := s.headServerCount[oldHead]
+		if h.serverCount--; h.serverCount > 0 {
+			s.headServerCount[oldHead] = h
+		} else {
+			delete(s.headServerCount, oldHead)
+		}
+	}
+	if head != (types.HeadInfo{}) {
+		h, ok := s.headServerCount[head]
+		if !ok {
+			s.headCounter++
+			h.headCounter = s.headCounter
+		}
+		h.serverCount++
+		s.headServerCount[head] = h
+		s.serverHeads[server] = head
+	} else {
+		delete(s.serverHeads, server)
+	}
+	var (
+		bestHead     types.HeadInfo
+		bestHeadInfo headServerCount
+	)
+	for head, headServerCount := range s.headServerCount {
+		if headServerCount.serverCount > bestHeadInfo.serverCount ||
+			(headServerCount.serverCount == bestHeadInfo.serverCount && headServerCount.headCounter > bestHeadInfo.headCounter) {
+			bestHead, bestHeadInfo = head, headServerCount
+		}
+	}
+	if bestHead == s.prefetchHead {
+		return false
+	}
+	s.prefetchHead = bestHead
+	s.headTracker.SetPrefetchHead(bestHead)
+	return true
+}

beacon/light/sync/head_sync_test.go

@@ -0,0 +1,183 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package sync
+
+import (
+	"testing"
+
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+var (
+	testServer1 = testServer("testServer1")
+	testServer2 = testServer("testServer2")
+	testServer3 = testServer("testServer3")
+	testServer4 = testServer("testServer4")
+	testServer5 = testServer("testServer5")
+
+	testHead0 = types.HeadInfo{}
+	testHead1 = types.HeadInfo{Slot: 123, BlockRoot: common.Hash{1}}
+	testHead2 = types.HeadInfo{Slot: 124, BlockRoot: common.Hash{2}}
+	testHead3 = types.HeadInfo{Slot: 124, BlockRoot: common.Hash{3}}
+	testHead4 = types.HeadInfo{Slot: 125, BlockRoot: common.Hash{4}}
+
+	testOptUpdate1 = types.OptimisticUpdate{SignatureSlot: 0x0124, Attested: types.HeaderWithExecProof{Header: types.Header{Slot: 0x0123, StateRoot: common.Hash{1}}}}
+	testOptUpdate2 = types.OptimisticUpdate{SignatureSlot: 0x2010, Attested: types.HeaderWithExecProof{Header: types.Header{Slot: 0x200e, StateRoot: common.Hash{2}}}}
+	// testOptUpdate3 is at the end of period 1 but signed in period 2
+	testOptUpdate3 = types.OptimisticUpdate{SignatureSlot: 0x4000, Attested: types.HeaderWithExecProof{Header: types.Header{Slot: 0x3fff, StateRoot: common.Hash{3}}}}
+	testOptUpdate4 = types.OptimisticUpdate{SignatureSlot: 0x6444, Attested: types.HeaderWithExecProof{Header: types.Header{Slot: 0x6443, StateRoot: common.Hash{4}}}}
+)
+
+func finality(opt types.OptimisticUpdate) types.FinalityUpdate {
+	return types.FinalityUpdate{
+		SignatureSlot: opt.SignatureSlot,
+		Attested:      opt.Attested,
+		Finalized:     types.HeaderWithExecProof{Header: types.Header{Slot: (opt.Attested.Header.Slot - 64) & uint64(0xffffffffffffffe0)}},
+	}
+}
+
+type testServer string
+
+func (t testServer) Name() string {
+	return string(t)
+}
+
+func TestValidatedHead(t *testing.T) {
+	chain := &TestCommitteeChain{}
+	ht := &TestHeadTracker{}
+	headSync := NewHeadSync(ht, chain)
+	ts := NewTestScheduler(t, headSync)
+
+	ht.ExpValidated(t, 0, nil)
+
+	ts.AddServer(testServer1, 1)
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer1, testOptUpdate1)
+	ts.Run(1, testServer1, ReqFinality{})
+	// announced head should be queued because of uninitialized chain
+	ht.ExpValidated(t, 1, nil)
+
+	chain.SetNextSyncPeriod(0) // initialize chain
+	ts.Run(2)
+	// expect previously queued head to be validated
+	ht.ExpValidated(t, 2, []types.OptimisticUpdate{testOptUpdate1})
+
+	chain.SetNextSyncPeriod(1)
+	ts.ServerEvent(EvNewFinalityUpdate, testServer1, finality(testOptUpdate2))
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer1, testOptUpdate2)
+	ts.AddServer(testServer2, 1)
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer2, testOptUpdate2)
+	ts.Run(3)
+	// expect both head announcements to be validated instantly
+	ht.ExpValidated(t, 3, []types.OptimisticUpdate{testOptUpdate2, testOptUpdate2})
+
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer1, testOptUpdate3)
+	ts.AddServer(testServer3, 1)
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer3, testOptUpdate4)
+	// finality should be requested from both servers
+	ts.Run(4, testServer1, ReqFinality{}, testServer3, ReqFinality{})
+	// future period announced heads should be queued
+	ht.ExpValidated(t, 4, nil)
+
+	chain.SetNextSyncPeriod(2)
+	ts.Run(5)
+	// testOptUpdate3 can be validated now but not testOptUpdate4
+	ht.ExpValidated(t, 5, []types.OptimisticUpdate{testOptUpdate3})
+
+	ts.AddServer(testServer4, 1)
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer4, testOptUpdate3)
+	// new server joined with recent optimistic update but still no finality; should be requested
+	ts.Run(6, testServer4, ReqFinality{})
+	ht.ExpValidated(t, 6, []types.OptimisticUpdate{testOptUpdate3})
+
+	ts.AddServer(testServer5, 1)
+	ts.RequestEvent(request.EvResponse, ts.Request(6, 1), finality(testOptUpdate3))
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer5, testOptUpdate3)
+	// finality update request answered; new server should not be requested
+	ts.Run(7)
+	ht.ExpValidated(t, 7, []types.OptimisticUpdate{testOptUpdate3})
+
+	// server 3 disconnected without proving period 3, its announced head should be dropped
+	ts.RemoveServer(testServer3)
+	ts.Run(8)
+	ht.ExpValidated(t, 8, nil)
+
+	chain.SetNextSyncPeriod(3)
+	ts.Run(9)
+	// testOptUpdate4 could be validated now but it's not queued by any registered server
+	ht.ExpValidated(t, 9, nil)
+
+	ts.ServerEvent(EvNewFinalityUpdate, testServer2, finality(testOptUpdate4))
+	ts.ServerEvent(EvNewOptimisticUpdate, testServer2, testOptUpdate4)
+	ts.Run(10)
+	// now testOptUpdate4 should be validated
+	ht.ExpValidated(t, 10, []types.OptimisticUpdate{testOptUpdate4})
+}
+
+func TestPrefetchHead(t *testing.T) {
+	chain := &TestCommitteeChain{}
+	ht := &TestHeadTracker{}
+	headSync := NewHeadSync(ht, chain)
+	ts := NewTestScheduler(t, headSync)
+
+	ht.ExpPrefetch(t, 0, testHead0) // no servers registered
+
+	ts.AddServer(testServer1, 1)
+	ts.ServerEvent(EvNewHead, testServer1, testHead1)
+	ts.Run(1)
+	ht.ExpPrefetch(t, 1, testHead1) // s1: h1
+
+	ts.AddServer(testServer2, 1)
+	ts.ServerEvent(EvNewHead, testServer2, testHead2)
+	ts.Run(2)
+	ht.ExpPrefetch(t, 2, testHead2) // s1: h1, s2: h2
+
+	ts.ServerEvent(EvNewHead, testServer1, testHead2)
+	ts.Run(3)
+	ht.ExpPrefetch(t, 3, testHead2) // s1: h2, s2: h2
+
+	ts.AddServer(testServer3, 1)
+	ts.ServerEvent(EvNewHead, testServer3, testHead3)
+	ts.Run(4)
+	ht.ExpPrefetch(t, 4, testHead2) // s1: h2, s2: h2, s3: h3
+
+	ts.AddServer(testServer4, 1)
+	ts.ServerEvent(EvNewHead, testServer4, testHead4)
+	ts.Run(5)
+	ht.ExpPrefetch(t, 5, testHead2) // s1: h2, s2: h2, s3: h3, s4: h4
+
+	ts.ServerEvent(EvNewHead, testServer2, testHead3)
+	ts.Run(6)
+	ht.ExpPrefetch(t, 6, testHead3) // s1: h2, s2: h3, s3: h3, s4: h4
+
+	ts.RemoveServer(testServer3)
+	ts.Run(7)
+	ht.ExpPrefetch(t, 7, testHead4) // s1: h2, s2: h3, s4: h4
+
+	ts.RemoveServer(testServer1)
+	ts.Run(8)
+	ht.ExpPrefetch(t, 8, testHead4) // s2: h3, s4: h4
+
+	ts.RemoveServer(testServer4)
+	ts.Run(9)
+	ht.ExpPrefetch(t, 9, testHead3) // s2: h3
+
+	ts.RemoveServer(testServer2)
+	ts.Run(10)
+	ht.ExpPrefetch(t, 10, testHead0) // no servers registered
+}

beacon/light/sync/test_helpers.go

@@ -0,0 +1,259 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package sync
+
+import (
+	"reflect"
+	"testing"
+
+	"github.com/ethereum/go-ethereum/beacon/light"
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/types"
+)
+
+type requestWithID struct {
+	sid     request.ServerAndID
+	request request.Request
+}
+
+type TestScheduler struct {
+	t         *testing.T
+	module    request.Module
+	events    []request.Event
+	servers   []request.Server
+	allowance map[request.Server]int
+	sent      map[int][]requestWithID
+	testIndex int
+	expFail   map[request.Server]int // expected Server.Fail calls during next Run
+	lastId    request.ID
+}
+
+func NewTestScheduler(t *testing.T, module request.Module) *TestScheduler {
+	return &TestScheduler{
+		t:         t,
+		module:    module,
+		allowance: make(map[request.Server]int),
+		expFail:   make(map[request.Server]int),
+		sent:      make(map[int][]requestWithID),
+	}
+}
+
+func (ts *TestScheduler) Run(testIndex int, exp ...any) {
+	expReqs := make([]requestWithID, len(exp)/2)
+	id := ts.lastId
+	for i := range expReqs {
+		id++
+		expReqs[i] = requestWithID{
+			sid:     request.ServerAndID{Server: exp[i*2].(request.Server), ID: id},
+			request: exp[i*2+1].(request.Request),
+		}
+	}
+	if len(expReqs) == 0 {
+		expReqs = nil
+	}
+
+	ts.testIndex = testIndex
+	ts.module.Process(ts, ts.events)
+	ts.events = nil
+
+	for server, count := range ts.expFail {
+		delete(ts.expFail, server)
+		if count == 0 {
+			continue
+		}
+		ts.t.Errorf("Missing %d Server.Fail(s) from server %s in test case #%d", count, server.Name(), testIndex)
+	}
+
+	if !reflect.DeepEqual(ts.sent[testIndex], expReqs) {
+		ts.t.Errorf("Wrong sent requests in test case #%d (expected %v, got %v)", testIndex, expReqs, ts.sent[testIndex])
+	}
+}
+
+func (ts *TestScheduler) CanSendTo() (cs []request.Server) {
+	for _, server := range ts.servers {
+		if ts.allowance[server] > 0 {
+			cs = append(cs, server)
+		}
+	}
+	return
+}
+
+func (ts *TestScheduler) Send(server request.Server, req request.Request) request.ID {
+	ts.lastId++
+	ts.sent[ts.testIndex] = append(ts.sent[ts.testIndex], requestWithID{
+		sid:     request.ServerAndID{Server: server, ID: ts.lastId},
+		request: req,
+	})
+	ts.allowance[server]--
+	return ts.lastId
+}
+
+func (ts *TestScheduler) Fail(server request.Server, desc string) {
+	if ts.expFail[server] == 0 {
+		ts.t.Errorf("Unexpected Fail from server %s in test case #%d: %s", server.Name(), ts.testIndex, desc)
+		return
+	}
+	ts.expFail[server]--
+}
+
+func (ts *TestScheduler) Request(testIndex, reqIndex int) requestWithID {
+	if len(ts.sent[testIndex]) < reqIndex {
+		ts.t.Errorf("Missing request from test case %d index %d", testIndex, reqIndex)
+		return requestWithID{}
+	}
+	return ts.sent[testIndex][reqIndex-1]
+}
+
+func (ts *TestScheduler) ServerEvent(evType *request.EventType, server request.Server, data any) {
+	ts.events = append(ts.events, request.Event{
+		Type:   evType,
+		Server: server,
+		Data:   data,
+	})
+}
+
+func (ts *TestScheduler) RequestEvent(evType *request.EventType, req requestWithID, resp request.Response) {
+	if req.request == nil {
+		return
+	}
+	ts.events = append(ts.events, request.Event{
+		Type:   evType,
+		Server: req.sid.Server,
+		Data: request.RequestResponse{
+			ID:       req.sid.ID,
+			Request:  req.request,
+			Response: resp,
+		},
+	})
+}
+
+func (ts *TestScheduler) AddServer(server request.Server, allowance int) {
+	ts.servers = append(ts.servers, server)
+	ts.allowance[server] = allowance
+	ts.ServerEvent(request.EvRegistered, server, nil)
+}
+
+func (ts *TestScheduler) RemoveServer(server request.Server) {
+	ts.servers = append(ts.servers, server)
+	for i, s := range ts.servers {
+		if s == server {
+			copy(ts.servers[i:len(ts.servers)-1], ts.servers[i+1:])
+			ts.servers = ts.servers[:len(ts.servers)-1]
+			break
+		}
+	}
+	delete(ts.allowance, server)
+	ts.ServerEvent(request.EvUnregistered, server, nil)
+}
+
+func (ts *TestScheduler) AddAllowance(server request.Server, allowance int) {
+	ts.allowance[server] += allowance
+}
+
+func (ts *TestScheduler) ExpFail(server request.Server) {
+	ts.expFail[server]++
+}
+
+type TestCommitteeChain struct {
+	fsp, nsp uint64
+	init     bool
+}
+
+func (tc *TestCommitteeChain) CheckpointInit(bootstrap types.BootstrapData) error {
+	tc.fsp, tc.nsp, tc.init = bootstrap.Header.SyncPeriod(), bootstrap.Header.SyncPeriod()+2, true
+	return nil
+}
+
+func (tc *TestCommitteeChain) InsertUpdate(update *types.LightClientUpdate, nextCommittee *types.SerializedSyncCommittee) error {
+	period := update.AttestedHeader.Header.SyncPeriod()
+	if period < tc.fsp || period > tc.nsp || !tc.init {
+		return light.ErrInvalidPeriod
+	}
+	if period == tc.nsp {
+		tc.nsp++
+	}
+	return nil
+}
+
+func (tc *TestCommitteeChain) NextSyncPeriod() (uint64, bool) {
+	return tc.nsp, tc.init
+}
+
+func (tc *TestCommitteeChain) ExpInit(t *testing.T, ExpInit bool) {
+	if tc.init != ExpInit {
+		t.Errorf("Incorrect init flag (expected %v, got %v)", ExpInit, tc.init)
+	}
+}
+
+func (tc *TestCommitteeChain) SetNextSyncPeriod(nsp uint64) {
+	tc.init, tc.nsp = true, nsp
+}
+
+func (tc *TestCommitteeChain) ExpNextSyncPeriod(t *testing.T, expNsp uint64) {
+	tc.ExpInit(t, true)
+	if tc.nsp != expNsp {
+		t.Errorf("Incorrect NextSyncPeriod (expected %d, got %d)", expNsp, tc.nsp)
+	}
+}
+
+type TestHeadTracker struct {
+	phead     types.HeadInfo
+	validated []types.OptimisticUpdate
+	finality  types.FinalityUpdate
+}
+
+func (ht *TestHeadTracker) ValidateOptimistic(update types.OptimisticUpdate) (bool, error) {
+	ht.validated = append(ht.validated, update)
+	return true, nil
+}
+
+func (ht *TestHeadTracker) ValidateFinality(update types.FinalityUpdate) (bool, error) {
+	ht.finality = update
+	return true, nil
+}
+
+func (ht *TestHeadTracker) ValidatedFinality() (types.FinalityUpdate, bool) {
+	return ht.finality, ht.finality.Attested.Header != (types.Header{})
+}
+
+func (ht *TestHeadTracker) ExpValidated(t *testing.T, tci int, expHeads []types.OptimisticUpdate) {
+	for i, expHead := range expHeads {
+		if i >= len(ht.validated) {
+			t.Errorf("Missing validated head in test case #%d index #%d (expected {slot %d blockRoot %x}, got none)", tci, i, expHead.Attested.Header.Slot, expHead.Attested.Header.Hash())
+			continue
+		}
+		if !reflect.DeepEqual(ht.validated[i], expHead) {
+			vhead := ht.validated[i].Attested.Header
+			t.Errorf("Wrong validated head in test case #%d index #%d (expected {slot %d blockRoot %x}, got {slot %d blockRoot %x})", tci, i, expHead.Attested.Header.Slot, expHead.Attested.Header.Hash(), vhead.Slot, vhead.Hash())
+		}
+	}
+	for i := len(expHeads); i < len(ht.validated); i++ {
+		vhead := ht.validated[i].Attested.Header
+		t.Errorf("Unexpected validated head in test case #%d index #%d (expected none, got {slot %d blockRoot %x})", tci, i, vhead.Slot, vhead.Hash())
+	}
+	ht.validated = nil
+}
+
+func (ht *TestHeadTracker) SetPrefetchHead(head types.HeadInfo) {
+	ht.phead = head
+}
+
+func (ht *TestHeadTracker) ExpPrefetch(t *testing.T, tci int, exp types.HeadInfo) {
+	if ht.phead != exp {
+		t.Errorf("Wrong prefetch head in test case #%d (expected {slot %d blockRoot %x}, got {slot %d blockRoot %x})", tci, exp.Slot, exp.BlockRoot, ht.phead.Slot, ht.phead.BlockRoot)
+	}
+}

beacon/light/sync/types.go

@@ -0,0 +1,47 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package sync
+
+import (
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+)
+
+var (
+	EvNewHead             = &request.EventType{Name: "newHead"}             // data: types.HeadInfo
+	EvNewOptimisticUpdate = &request.EventType{Name: "newOptimisticUpdate"} // data: types.OptimisticUpdate
+	EvNewFinalityUpdate   = &request.EventType{Name: "newFinalityUpdate"}   // data: types.FinalityUpdate
+)
+
+type (
+	ReqUpdates struct {
+		FirstPeriod, Count uint64
+	}
+	RespUpdates struct {
+		Updates    []*types.LightClientUpdate
+		Committees []*types.SerializedSyncCommittee
+	}
+	ReqHeader  common.Hash
+	RespHeader struct {
+		Header               types.Header
+		Canonical, Finalized bool
+	}
+	ReqCheckpointData common.Hash
+	ReqBeaconBlock    common.Hash
+	ReqFinality       struct{}
+)

beacon/light/sync/update_sync.go

@@ -0,0 +1,398 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package sync
+
+import (
+	"sort"
+
+	"github.com/ethereum/go-ethereum/beacon/light"
+	"github.com/ethereum/go-ethereum/beacon/light/request"
+	"github.com/ethereum/go-ethereum/beacon/params"
+	"github.com/ethereum/go-ethereum/beacon/types"
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+const maxUpdateRequest = 8 // maximum number of updates requested in a single request
+
+type committeeChain interface {
+	CheckpointInit(bootstrap types.BootstrapData) error
+	InsertUpdate(update *types.LightClientUpdate, nextCommittee *types.SerializedSyncCommittee) error
+	NextSyncPeriod() (uint64, bool)
+}
+
+// CheckpointInit implements request.Module; it fetches the light client bootstrap
+// data belonging to the given checkpoint hash and initializes the committee chain
+// if successful.
+type CheckpointInit struct {
+	chain          committeeChain
+	checkpointHash common.Hash
+	locked         request.ServerAndID
+	initialized    bool
+	// per-server state is used to track the state of requesting checkpoint header
+	// info. Part of this info (canonical and finalized state) is not validated
+	// and therefore it is requested from each server separately after it has
+	// reported a missing checkpoint (which is also not validated info).
+	serverState map[request.Server]serverState
+	// the following fields are used to determine whether the checkpoint is on
+	// epoch boundary. This information is validated and therefore stored globally.
+	parentHash                  common.Hash
+	hasEpochInfo, epochBoundary bool
+	cpSlot, parentSlot          uint64
+}
+
+const (
+	ssDefault         = iota // no action yet or checkpoint requested
+	ssNeedHeader             // checkpoint req failed, need cp header
+	ssHeaderRequested        // cp header requested
+	ssNeedParent             // cp header slot %32 != 0, need parent to check epoch boundary
+	ssParentRequested        // cp parent header requested
+	ssPrintStatus            // has all necessary info, print log message if init still not successful
+	ssDone                   // log message printed, no more action required
+)
+
+type serverState struct {
+	state                           int
+	hasHeader, canonical, finalized bool // stored per server because not validated
+}
+
+// NewCheckpointInit creates a new CheckpointInit.
+func NewCheckpointInit(chain committeeChain, checkpointHash common.Hash) *CheckpointInit {
+	return &CheckpointInit{
+		chain:          chain,
+		checkpointHash: checkpointHash,
+		serverState:    make(map[request.Server]serverState),
+	}
+}
+
+// Process implements request.Module.
+func (s *CheckpointInit) Process(requester request.Requester, events []request.Event) {
+	if s.initialized {
+		return
+	}
+
+	for _, event := range events {
+		switch event.Type {
+		case request.EvResponse, request.EvFail, request.EvTimeout:
+			sid, req, resp := event.RequestInfo()
+			if s.locked == sid {
+				s.locked = request.ServerAndID{}
+			}
+			if event.Type == request.EvTimeout {
+				continue
+			}
+			switch s.serverState[sid.Server].state {
+			case ssDefault:
+				if resp != nil {
+					if checkpoint := resp.(*types.BootstrapData); checkpoint.Header.Hash() == common.Hash(req.(ReqCheckpointData)) {
+						s.chain.CheckpointInit(*checkpoint)
+						s.initialized = true
+						return
+					}
+					requester.Fail(event.Server, "invalid checkpoint data")
+				}
+				s.serverState[sid.Server] = serverState{state: ssNeedHeader}
+			case ssHeaderRequested:
+				if resp == nil {
+					s.serverState[sid.Server] = serverState{state: ssPrintStatus}
+					continue
+				}
+				newState := serverState{
+					hasHeader: true,
+					canonical: resp.(RespHeader).Canonical,
+					finalized: resp.(RespHeader).Finalized,
+				}
+				s.cpSlot, s.parentHash = resp.(RespHeader).Header.Slot, resp.(RespHeader).Header.ParentRoot
+				if s.cpSlot%params.EpochLength == 0 {
+					s.hasEpochInfo, s.epochBoundary = true, true
+				}
+				if s.hasEpochInfo {
+					newState.state = ssPrintStatus
+				} else {
+					newState.state = ssNeedParent
+				}
+				s.serverState[sid.Server] = newState
+			case ssParentRequested:
+				s.parentSlot = resp.(RespHeader).Header.Slot
+				s.hasEpochInfo, s.epochBoundary = true, s.cpSlot/params.EpochLength > s.parentSlot/params.EpochLength
+				newState := s.serverState[sid.Server]
+				newState.state = ssPrintStatus
+				s.serverState[sid.Server] = newState
+			}
+
+		case request.EvUnregistered:
+			delete(s.serverState, event.Server)
+		}
+	}
+
+	// start a request if possible
+	for _, server := range requester.CanSendTo() {
+		switch s.serverState[server].state {
+		case ssDefault:
+			if s.locked == (request.ServerAndID{}) {
+				id := requester.Send(server, ReqCheckpointData(s.checkpointHash))
+				s.locked = request.ServerAndID{Server: server, ID: id}
+			}
+		case ssNeedHeader:
+			requester.Send(server, ReqHeader(s.checkpointHash))
+			newState := s.serverState[server]
+			newState.state = ssHeaderRequested
+			s.serverState[server] = newState
+		case ssNeedParent:
+			requester.Send(server, ReqHeader(s.parentHash))
+			newState := s.serverState[server]
+			newState.state = ssParentRequested
+			s.serverState[server] = newState
+		}
+	}
+
+	// print log message if necessary
+	for server, state := range s.serverState {
+		if state.state != ssPrintStatus {
+			continue
+		}
+		switch {
+		case !state.hasHeader:
+			log.Error("blsync: checkpoint block is not available, reported as unknown", "server", server.Name())
+		case !state.canonical:
+			log.Error("blsync: checkpoint block is not available, reported as non-canonical", "server", server.Name())
+		case !s.hasEpochInfo:
+			// should be available if hasHeader is true and state is ssPrintStatus
+			panic("checkpoint epoch info not available when printing retrieval status")
+		case !s.epochBoundary:
+			log.Error("blsync: checkpoint block is not first of epoch", "slot", s.cpSlot, "parent", s.parentSlot, "server", server.Name())
+		case !state.finalized:
+			log.Error("blsync: checkpoint block is reported as non-finalized", "server", server.Name())
+		default:
+			log.Error("blsync: checkpoint not available, but reported as finalized; specified checkpoint hash might be too old", "server", server.Name())
+		}
+		s.serverState[server] = serverState{state: ssDone}
+	}
+}
+
+// ForwardUpdateSync implements request.Module; it fetches updates between the
+// committee chain head and each server's announced head. Updates are fetched
+// in batches and multiple batches can also be requested in parallel.
+// Out of order responses are also handled; if a batch of updates cannot be added
+// to the chain immediately because of a gap then the future updates are
+// remembered until they can be processed.
+type ForwardUpdateSync struct {
+	chain          committeeChain
+	rangeLock      rangeLock
+	lockedIDs      map[request.ServerAndID]struct{}
+	processQueue   []updateResponse
+	nextSyncPeriod map[request.Server]uint64
+}
+
+// NewForwardUpdateSync creates a new ForwardUpdateSync.
+func NewForwardUpdateSync(chain committeeChain) *ForwardUpdateSync {
+	return &ForwardUpdateSync{
+		chain:          chain,
+		rangeLock:      make(rangeLock),
+		lockedIDs:      make(map[request.ServerAndID]struct{}),
+		nextSyncPeriod: make(map[request.Server]uint64),
+	}
+}
+
+// rangeLock allows locking sections of an integer space, preventing the syncing
+// mechanism from making requests again for sections where a not timed out request
+// is already pending or where already fetched and unprocessed data is available.
+type rangeLock map[uint64]int
+
+// lock locks or unlocks the given section, depending on the sign of the add parameter.
+func (r rangeLock) lock(first, count uint64, add int) {
+	for i := first; i < first+count; i++ {
+		if v := r[i] + add; v > 0 {
+			r[i] = v
+		} else {
+			delete(r, i)
+		}
+	}
+}
+
+// firstUnlocked returns the first unlocked section starting at or after start
+// and not longer than maxCount.
+func (r rangeLock) firstUnlocked(start, maxCount uint64) (first, count uint64) {
+	first = start
+	for {
+		if _, ok := r[first]; !ok {
+			break
+		}
+		first++
+	}
+	for {
+		count++
+		if count == maxCount {
+			break
+		}
+		if _, ok := r[first+count]; ok {
+			break
+		}
+	}
+	return
+}
+
+// lockRange locks the range belonging to the given update request, unless the
+// same request has already been locked
+func (s *ForwardUpdateSync) lockRange(sid request.ServerAndID, req ReqUpdates) {
+	if _, ok := s.lockedIDs[sid]; ok {
+		return
+	}
+	s.lockedIDs[sid] = struct{}{}
+	s.rangeLock.lock(req.FirstPeriod, req.Count, 1)
+}
+
+// unlockRange unlocks the range belonging to the given update request, unless
+// same request has already been unlocked
+func (s *ForwardUpdateSync) unlockRange(sid request.ServerAndID, req ReqUpdates) {
+	if _, ok := s.lockedIDs[sid]; !ok {
+		return
+	}
+	delete(s.lockedIDs, sid)
+	s.rangeLock.lock(req.FirstPeriod, req.Count, -1)
+}
+
+// verifyRange returns true if the number of updates and the individual update
+// periods in the response match the requested section.
+func (s *ForwardUpdateSync) verifyRange(request ReqUpdates, response RespUpdates) bool {
+	if uint64(len(response.Updates)) != request.Count || uint64(len(response.Committees)) != request.Count {
+		return false
+	}
+	for i, update := range response.Updates {
+		if update.AttestedHeader.Header.SyncPeriod() != request.FirstPeriod+uint64(i) {
+			return false
+		}
+	}
+	return true
+}
+
+// updateResponse is a response that has passed initial verification and has been
+// queued for processing. Note that an update response cannot be processed until
+// the previous updates have also been added to the chain.
+type updateResponse struct {
+	sid      request.ServerAndID
+	request  ReqUpdates
+	response RespUpdates
+}
+
+// updateResponseList implements sort.Sort and sorts update request/response events by FirstPeriod.
+type updateResponseList []updateResponse
+
+func (u updateResponseList) Len() int      { return len(u) }
+func (u updateResponseList) Swap(i, j int) { u[i], u[j] = u[j], u[i] }
+func (u updateResponseList) Less(i, j int) bool {
+	return u[i].request.FirstPeriod < u[j].request.FirstPeriod
+}
+
+// Process implements request.Module.
+func (s *ForwardUpdateSync) Process(requester request.Requester, events []request.Event) {
+	for _, event := range events {
+		switch event.Type {
+		case request.EvResponse, request.EvFail, request.EvTimeout:
+			sid, rq, rs := event.RequestInfo()
+			req := rq.(ReqUpdates)
+			var queued bool
+			if event.Type == request.EvResponse {
+				resp := rs.(RespUpdates)
+				if s.verifyRange(req, resp) {
+					// there is a response with a valid format; put it in the process queue
+					s.processQueue = append(s.processQueue, updateResponse{sid: sid, request: req, response: resp})
+					s.lockRange(sid, req)
+					queued = true
+				} else {
+					requester.Fail(event.Server, "invalid update range")
+				}
+			}
+			if !queued {
+				s.unlockRange(sid, req)
+			}
+		case EvNewOptimisticUpdate:
+			update := event.Data.(types.OptimisticUpdate)
+			s.nextSyncPeriod[event.Server] = types.SyncPeriod(update.SignatureSlot + 256)
+		case request.EvUnregistered:
+			delete(s.nextSyncPeriod, event.Server)
+		}
+	}
+
+	// try processing ordered list of available responses
+	sort.Sort(updateResponseList(s.processQueue))
+	for s.processQueue != nil {
+		u := s.processQueue[0]
+		if !s.processResponse(requester, u) {
+			break
+		}
+		s.unlockRange(u.sid, u.request)
+		s.processQueue = s.processQueue[1:]
+		if len(s.processQueue) == 0 {
+			s.processQueue = nil
+		}
+	}
+
+	// start new requests if possible
+	startPeriod, chainInit := s.chain.NextSyncPeriod()
+	if !chainInit {
+		return
+	}
+	for {
+		firstPeriod, maxCount := s.rangeLock.firstUnlocked(startPeriod, maxUpdateRequest)
+		var (
+			sendTo    request.Server
+			bestCount uint64
+		)
+		for _, server := range requester.CanSendTo() {
+			nextPeriod := s.nextSyncPeriod[server]
+			if nextPeriod <= firstPeriod {
+				continue
+			}
+			count := maxCount
+			if nextPeriod < firstPeriod+maxCount {
+				count = nextPeriod - firstPeriod
+			}
+			if count > bestCount {
+				sendTo, bestCount = server, count
+			}
+		}
+		if sendTo == nil {
+			return
+		}
+		req := ReqUpdates{FirstPeriod: firstPeriod, Count: bestCount}
+		id := requester.Send(sendTo, req)
+		s.lockRange(request.ServerAndID{Server: sendTo, ID: id}, req)
+	}
+}
+
+// processResponse adds the fetched updates and committees to the committee chain.
+// Returns true in case of full or partial success.
+func (s *ForwardUpdateSync) processResponse(requester request.Requester, u updateResponse) (success bool) {
+	for i, update := range u.response.Updates {
+		if err := s.chain.InsertUpdate(update, u.response.Committees[i]); err != nil {
+			if err == light.ErrInvalidPeriod {
+				// there is a gap in the update periods; stop processing without
+				// failing and try again next time
+				return
+			}
+			if err == light.ErrInvalidUpdate || err == light.ErrWrongCommitteeRoot || err == light.ErrCannotReorg {
+				requester.Fail(u.sid.Server, "invalid update received")
+			} else {
+				log.Error("Unexpected InsertUpdate error", "error", err)
+			}
+			return
+		}
+		success = true
+	}
+	return
+}