fix: swap errors (Uniswap#431)

src/hooks/useUniversalRouter.ts

@@ -1,5 +1,6 @@
 import { BigNumber } from '@ethersproject/bignumber'
-import { TransactionResponse } from '@ethersproject/providers'
+import { TransactionRequest, TransactionResponse } from '@ethersproject/providers'
+import { t } from '@lingui/macro'
 import { Percent } from '@uniswap/sdk-core'
 import { SwapRouter, UNIVERSAL_ROUTER_ADDRESS } from '@uniswap/universal-router-sdk'
 import { FeeOptions, toHex } from '@uniswap/v3-sdk'
@@ -23,6 +24,8 @@ export function useUniversalRouterSwapCallback(trade: InterfaceTrade | undefined
   const { account, chainId, provider } = useWeb3React()
 
   return useCallback(async (): Promise<TransactionResponse> => {
+    let tx: TransactionRequest
+    let response: TransactionResponse
     try {
       if (!account) throw new Error('missing account')
       if (!chainId) throw new Error('missing chainId')
@@ -35,7 +38,7 @@ export function useUniversalRouterSwapCallback(trade: InterfaceTrade | undefined
         inputTokenPermit: options.permit,
         fee: options.feeOptions,
       })
-      const tx = {
+      tx = {
         from: account,
         to: UNIVERSAL_ROUTER_ADDRESS(chainId),
         data,
@@ -47,16 +50,21 @@ export function useUniversalRouterSwapCallback(trade: InterfaceTrade | undefined
       try {
         gasEstimate = await provider.estimateGas(tx)
       } catch (gasError) {
-        await provider.call(tx) // this should throw the actual error
-        throw new Error('unexpected issue with gas estimation; please try again')
+        console.warn(gasError)
+        throw new Error('Your swap is expected to fail')
       }
       const gasLimit = calculateGasMargin(gasEstimate)
-      const response = await provider.getSigner().sendTransaction({ ...tx, gasLimit })
-      return response
+      response = await provider.getSigner().sendTransaction({ ...tx, gasLimit })
     } catch (swapError: unknown) {
       const message = swapErrorToUserReadableMessage(swapError)
-      throw new Error(`Trade failed: ${message}`)
+      throw new Error(message)
     }
+    if (tx.data !== response.data) {
+      throw new Error(
+        t`Your swap was modified through your wallet. If this was a mistake, please cancel immediately or risk losing your funds.`
+      )
+    }
+    return response
   }, [
     account,
     chainId,

src/utils/swapErrorToUserReadableMessage.tsx

@@ -22,7 +22,7 @@ export function swapErrorToUserReadableMessage(error: any): string {
 
   switch (reason) {
     case 'UniswapV2Router: EXPIRED':
-      return t`The transaction could not be sent because the deadline has passed. Please check that your transaction deadline is not too low.`
+      return t`This transaction could not be sent because the deadline has passed. Please check that your transaction deadline is not too low.`
     case 'UniswapV2Router: INSUFFICIENT_OUTPUT_AMOUNT':
     case 'UniswapV2Router: EXCESSIVE_INPUT_AMOUNT':
       return t`This transaction will not succeed either due to price movement or fee on transfer. Try increasing your slippage tolerance.`
@@ -43,8 +43,7 @@ export function swapErrorToUserReadableMessage(error: any): string {
         console.error(error, reason)
         return t`An error occurred when trying to execute this swap. You may need to increase your slippage tolerance. If that does not work, there may be an incompatibility with the token you are trading. Note: fee on transfer and rebase tokens are incompatible with Uniswap V3.`
       }
-      return t`Unknown error${
-        reason ? `: "${reason}"` : ''
-      }. Try increasing your slippage tolerance. Note: fee on transfer and rebase tokens are incompatible with Uniswap V3.`
+      return t`${reason ? reason : 'Unknown error'}. Try increasing your slippage tolerance.
+Note: fee-on-transfer and rebase tokens are incompatible with Uniswap V3.`
   }
 }