Correct handling of Chai to Dai swaps in oracle and monitor components (#302)

contracts

@@ -1 +1 @@
-Subproject commit 026dbfdac8eb067af078a69483f474051a8a6379
+Subproject commit c073e830679fdab0807d7c5a004bd8bd25f9fdca

monitor/utils/events.js

@@ -112,7 +112,26 @@ async function main(mode) {
       const bridgeTokensSwappedEvents = tokensSwappedEvents.filter(e => e.address === COMMON_FOREIGN_BRIDGE_ADDRESS)
 
       // Get transfer events for each previous erc20
-      const uniqueTokenAddresses = [...new Set(bridgeTokensSwappedEvents.map(e => e.returnValues.from))]
+      const uniqueTokenAddressesSet = new Set(bridgeTokensSwappedEvents.map(e => e.returnValues.from))
+
+      // Exclude chai token from previous erc20
+      try {
+        logger.debug('calling foreignBridge.chaiToken()')
+        const chaiToken = await foreignBridge.methods.chaiToken().call()
+        uniqueTokenAddressesSet.delete(chaiToken)
+      } catch (e) {
+        logger.debug('call to foreignBridge.chaiToken() failed')
+      }
+      // Exclude dai token from previous erc20
+      try {
+        logger.debug('calling foreignBridge.erc20token()')
+        const daiToken = await foreignBridge.methods.erc20token().call()
+        uniqueTokenAddressesSet.delete(daiToken)
+      } catch (e) {
+        logger.debug('call to foreignBridge.erc20token() failed')
+      }
+
+      const uniqueTokenAddresses = [...uniqueTokenAddressesSet]
       await Promise.all(
         uniqueTokenAddresses.map(async tokenAddress => {
           const halfDuplexTokenContract = new web3Foreign.eth.Contract(ERC20_ABI, tokenAddress)

oracle-e2e/test/ercToNative.js

@@ -552,4 +552,122 @@ describe('erc to native', () => {
       }
     })
   })
+
+  describe('handling of chai swaps', async () => {
+    before(async () => {
+      // Next tests check validator nonces, this will force every validator to submit signature/affirmation
+      // Set 3 required signatures for home bridge
+      await setRequiredSignatures({
+        bridgeContract: homeBridge,
+        web3: homeWeb3,
+        requiredSignatures: 3,
+        options: {
+          from: validator.address,
+          gas: '4000000'
+        }
+      })
+
+      // Set 3 required signatures for foreign bridge
+      await setRequiredSignatures({
+        bridgeContract: foreignBridge,
+        web3: foreignWeb3,
+        requiredSignatures: 3,
+        options: {
+          from: validator.address,
+          gas: '4000000'
+        }
+      })
+    })
+
+    it('should not handle transfer event in paying interest', async () => {
+      await foreignBridge.methods.setInterestReceiver(user.address).send({
+        from: validator.address,
+        gas: '1000000'
+      })
+      const initialNonce = await homeWeb3.eth.getTransactionCount(validator.address)
+      await foreignBridge.methods.payInterest().send({
+        from: user.address,
+        gas: '1000000'
+      })
+
+      await promiseRetry(async (retry, number) => {
+        if (number < 6) {
+          retry()
+        } else {
+          const nonce = await homeWeb3.eth.getTransactionCount(validator.address)
+          assert(
+            nonce === initialNonce,
+            'Validator should not process transfer event originated during converting Chai => Dai'
+          )
+        }
+      })
+    })
+
+    it('should not handle chai withdrawal transfer event in executeSignatures as a regular transfer', async () => {
+      await foreignBridge.methods.setMinDaiTokenBalance('0').send({
+        from: validator.address,
+        gas: '1000000'
+      }) // set investing limit to 0
+      await foreignBridge.methods.convertDaiToChai().send({
+        from: validator.address,
+        gas: '1000000'
+      }) // convert all existing dai tokens on bridge account to chai, in order to start from zero balance
+
+      const initialNonce = await homeWeb3.eth.getTransactionCount(validator.address)
+
+      const originalBalance = await erc20Token.methods.balanceOf(user.address).call()
+      // send transaction to home bridge
+      await homeWeb3.eth.sendTransaction({
+        from: user.address,
+        to: COMMON_HOME_BRIDGE_ADDRESS,
+        gasPrice: '1',
+        gas: '1000000',
+        value: homeWeb3.utils.toWei('0.01')
+      })
+
+      // check that balance increases
+      await uniformRetry(async retry => {
+        const balance = await erc20Token.methods.balanceOf(user.address).call()
+        if (toBN(balance).lte(toBN(originalBalance))) {
+          retry()
+        }
+      })
+
+      await promiseRetry(async (retry, number) => {
+        if (number < 6) {
+          retry()
+        } else {
+          const nonce = await homeWeb3.eth.getTransactionCount(validator.address)
+          assert(
+            nonce === initialNonce + 1,
+            'Validator should not process transfer event originated during converting Chai => Dai'
+          )
+        }
+      })
+    })
+
+    after(async () => {
+      // Set 2 required signatures for home bridge
+      await setRequiredSignatures({
+        bridgeContract: homeBridge,
+        web3: homeWeb3,
+        requiredSignatures: 2,
+        options: {
+          from: validator.address,
+          gas: '4000000'
+        }
+      })
+
+      // Set 2 required signatures for foreign bridge
+      await setRequiredSignatures({
+        bridgeContract: foreignBridge,
+        web3: foreignWeb3,
+        requiredSignatures: 2,
+        options: {
+          from: validator.address,
+          gas: '4000000'
+        }
+      })
+    })
+  })
 })