fix(position fee computation): incorrect sub underflow

* initial impl

* fix async logic

src/components/PositionCard/index.tsx

@@ -213,12 +213,12 @@ export default function FullPositionCard({ pair, border, stakedBalance }: Positi
             >
               {showMore ? (
                 <>
-                  Migrate
+                  Manage
                   <ChevronUp size="20" style={{ marginLeft: '10px' }} />
                 </>
               ) : (
                 <>
-                  Migrate
+                  Manage
                   <ChevronDown size="20" style={{ marginLeft: '10px' }} />
                 </>
               )}
@@ -296,7 +296,7 @@ export default function FullPositionCard({ pair, border, stakedBalance }: Positi
             <ButtonSecondary padding="8px" borderRadius="8px">
               <ExternalLink
                 style={{ width: '100%', textAlign: 'center' }}
-                href={`https://info.uniswap.org/account/${account}`}
+                href={`https://v2.info.uniswap.org/account/${account}`}
               >
                 View accrued fees and analytics<span style={{ fontSize: '11px' }}>↗</span>
               </ExternalLink>

src/components/WalletModal/index.tsx

@@ -338,9 +338,10 @@ export default function WalletModal({
           <LightCard style={{ marginBottom: '16px' }}>
             <AutoRow style={{ flexWrap: 'nowrap' }}>
               <TYPE.main fontSize={14}>
-                By connecting a wallet, you agree to Uniswap Labs’ <ExternalLink href="">Terms of Service</ExternalLink>{' '}
-                and acknowledge that you have read and understand the{' '}
-                <ExternalLink href="">Uniswap protocol disclaimer</ExternalLink>.
+                By connecting a wallet, you agree to Uniswap Labs’{' '}
+                <ExternalLink href="https://uniswap.org/terms-of-service/">Terms of Service</ExternalLink> and
+                acknowledge that you have read and understand the{' '}
+                <ExternalLink href="https://uniswap.org/disclaimer/">Uniswap protocol disclaimer</ExternalLink>.
               </TYPE.main>
             </AutoRow>
           </LightCard>

src/components/earn/StakingModal.tsx

@@ -128,7 +128,18 @@ export default function StakingModal({ isOpen, onDismiss, stakingInfo, userLiqui
     if (!pairContract || !library || !deadline) throw new Error('missing dependencies')
     if (!parsedAmount) throw new Error('missing liquidity amount')
 
-    return gatherPermitSignature ? gatherPermitSignature() : approveCallback()
+    if (gatherPermitSignature) {
+      try {
+        await gatherPermitSignature()
+      } catch (error) {
+        // try to approve if gatherPermitSignature failed for any reason other than the user rejecting it
+        if (error?.code !== 4001) {
+          await approveCallback()
+        }
+      }
+    } else {
+      await approveCallback()
+    }
   }
 
   return (

src/hooks/useERC20Permit.ts

@@ -219,7 +219,7 @@ export function useERC20Permit(
           message,
         })
 
-        library
+        return library
           .send('eth_signTypedData_v4', [account, data])
           .then(splitSignature)
           .then((signature) => {

src/hooks/useV3PositionFees.ts

@@ -12,7 +12,7 @@ import { TokenAmount } from '@uniswap/sdk-core'
 
 function subIn256(x: BigNumber, y: BigNumber): BigNumber {
   const difference = x.sub(y)
-  return difference.lt(0) ? BigNumber.from(2).pow(256).sub(difference) : difference
+  return difference.lt(0) ? BigNumber.from(2).pow(256).add(difference) : difference
 }
 
 function getCounterfactualFees(

src/pages/MigrateV2/MigrateV2Pair.tsx

@@ -239,7 +239,21 @@ function V2PairMigration({
   const { signatureData, gatherPermitSignature } = useV2LiquidityTokenPermit(pairBalance, migratorAddress)
 
   const approve = useCallback(async () => {
-    isNotUniswap ? approveManually() : gatherPermitSignature ? gatherPermitSignature() : approveManually()
+    if (isNotUniswap) {
+      // sushi has to be manually approved
+      await approveManually()
+    } else if (gatherPermitSignature) {
+      try {
+        await gatherPermitSignature()
+      } catch (error) {
+        // try to approve if gatherPermitSignature failed for any reason other than the user rejecting it
+        if (error?.code !== 4001) {
+          await approveManually()
+        }
+      }
+    } else {
+      await approveManually()
+    }
   }, [isNotUniswap, gatherPermitSignature, approveManually])
 
   const addTransaction = useTransactionAdder()

src/pages/Pool/v2.tsx

@@ -192,7 +192,7 @@ export default function Pool() {
               <>
                 <ButtonSecondary>
                   <RowBetween>
-                    <ExternalLink href={'https://uniswap.info/account/' + account}>
+                    <ExternalLink href={'https://v2.info.uniswap.org/account/' + account}>
                       Account analytics and accrued fees
                     </ExternalLink>
                     <span> ↗</span>

src/pages/RemoveLiquidity/index.tsx

@@ -109,7 +109,18 @@ export default function RemoveLiquidity({
     const liquidityAmount = parsedAmounts[Field.LIQUIDITY]
     if (!liquidityAmount) throw new Error('missing liquidity amount')
 
-    return gatherPermitSignature ? gatherPermitSignature() : approveCallback()
+    if (gatherPermitSignature) {
+      try {
+        await gatherPermitSignature()
+      } catch (error) {
+        // try to approve if gatherPermitSignature failed for any reason other than the user rejecting it
+        if (error?.code !== 4001) {
+          await approveCallback()
+        }
+      }
+    } else {
+      await approveCallback()
+    }
   }
 
   // wrapped onUserInput to clear signatures

src/pages/Swap/index.tsx

@@ -205,9 +205,19 @@ export default function Swap({ history }: RouteComponentProps) {
     allowedSlippage
   )
 
-  const handleApprove = useCallback(() => {
-    if (signatureState === UseERC20PermitState.NOT_SIGNED && gatherPermitSignature) gatherPermitSignature()
-    else approveCallback()
+  const handleApprove = useCallback(async () => {
+    if (signatureState === UseERC20PermitState.NOT_SIGNED && gatherPermitSignature) {
+      try {
+        await gatherPermitSignature()
+      } catch (error) {
+        // try to approve if gatherPermitSignature failed for any reason other than the user rejecting it
+        if (error?.code !== 4001) {
+          await approveCallback()
+        }
+      }
+    } else {
+      await approveCallback()
+    }
   }, [approveCallback, gatherPermitSignature, signatureState])
 
   // check if user has gone through approval process, used to show two step buttons, reset on token change