"Buy Coffee" throws revert in anvil, but the transaction does go through

[rjdat]

I am in the Sending txn part of the course ( Buy Coffee project).

When I click the Buy Coffee button, anvil throws a bunch of these errors:

RPC request failed:
    Request: EthCall(WithOtherFields { inner: TransactionRequest { from: None, to: Some(Call(0xe7f1725e7734ce288f8367e1bb143e90bb3f0512)), gas_price: None, max_fee_per_gas: None, max_priority_fee_per_gas: None, max_fee_per_blob_gas: None, gas: None, value: None, input: TransactionInput { input: None, data: Some(0x313ce567) }, nonce: None, chain_id: None, access_list: None, transaction_type: None, blob_versioned_hashes: None, sidecar: None, authorization_list: None }, other: OtherFields {} }, Some(0x3), None, None)
    Error: Execution error: execution reverted

But the interesting part is: In spite of saying execution reverted , the txn still goes through ! (as confirmed by the correct output of console.log(balance) when I click "Get Balance")

My code:

import {
  createWalletClient,
  custom,
  formatEther,
  parseEther,
  defineChain,
  createPublicClient,
} from "https://esm.sh/viem"
import { abi, contractAddress } from "./constants-js.js"

const connectButton = document.getElementById("connectButton")
const fundButton = document.getElementById("fundButton")
const balanceButton = document.getElementById("balanceButton")
const withdrawButton = document.getElementById("withdrawButton")
const ethAmountInput = document.getElementById("ethAmount")

let walletClient
let publicClient

async function connect() {
  if (typeof window.ethereum !== "undefined") {
    walletClient = createWalletClient({
      transport: custom(window.ethereum),
    })
    await walletClient.requestAddresses()
    connectButton.innerHTML = "Connected"
  } else {
    connectButton.innerHTML = "Please install MetaMask"
  }
}

async function fund() {
  const ethAmount = ethAmountInput.value
  console.log(`Funding with ${ethAmount}...`)

  if (typeof window.ethereum !== "undefined") {
    try {
      walletClient = createWalletClient({
        transport: custom(window.ethereum),
      })
      const [account] = await walletClient.requestAddresses()
      const currentChain = await getCurrentChain(walletClient)

      console.log("Processing transaction...")
      publicClient = createPublicClient({
        transport: custom(window.ethereum),
      })
      const { request } = await publicClient.simulateContract({
        address: contractAddress,
        abi,
        functionName: "fund",
        account,
        chain: currentChain,
        value: parseEther(ethAmount),
      })
      const hash = await walletClient.writeContract(request)
      console.log("Transaction processed: ", hash)
    } catch (error) {
      console.log(error)
    }
  } else {
    fundButton.innerHTML = "Please install MetaMask"
  }
}

async function getBalance() {
  if (typeof window.ethereum !== "undefined") {
    try {
      publicClient = createPublicClient({
        transport: custom(window.ethereum),
      })
      const balance = await publicClient.getBalance({
        address: contractAddress,
      })
      console.log(formatEther(balance))
    } catch (error) {
      console.log(error)
    }
  } else {
    balanceButton.innerHTML = "Please install MetaMask"
  }
}
async function getCurrentChain(client) {
  const chainId = await client.getChainId()
  const currentChain = defineChain({
    id: chainId,
    name: "Custom Chain",
    nativeCurrency: {
      name: "Ether",
      symbol: "ETH",
      decimals: 18,
    },
    rpcUrls: {
      default: {
        http: ["http://localhost:8545"],
      },
    },
  })
  return currentChain
}

// Event listeners
connectButton.onclick = connect
fundButton.onclick = fund
balanceButton.onclick = getBalance
withdrawButton.onclick = withdraw

Some Personal Findings

Having completed the foundry-fund-me course, I deployed the contract to anvil, and spun up my anvil node (as opposed to doing anvil --load-state fundme-anvil.json), and used my own abi for the FundMe contract in constants-js.js.

With the above personal setup, I still do get the same error but it shows a didn't send enough ETH in the ending revert message. Lack of funds shouldn't be a problem since the minimum amount was $5 in the tutorial, which is certainly lesser than 1 ETH. When I did a

cast call 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512 "getAmtFunded(address)" 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 --rpc-url $RPC_URL --account anvil

, I got the response that the input amount had indeed been funded and so the transaction did went through.

Deepseek says this is a quirk of the frontend. I found a similar issue in the discussions: #32

[EngrPips]

If you run forge --version, what do you get?

[rjdat]

About the cast calls, yes, I have pasted the wrong command accidentally. I am sure the call didn't go through. I'll check once again though.

[rjdat]

Your cast call seems off for me, are you not supposed to pass in a uint256 such as 0, 1 or so as the argument why did you pass in 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266?

cast call 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512 "getFunder(uint256)" 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 --rpc-url $RPC_URL --account anvil

@EngrPips Thanks for pointing that out, actually. I took another look at it, and cast seems to be working fine at recording txns from the frontend, although that RPC request failed still exists.

Also, I noticed when I click Get Balance on the frontend after Buy Coffee, initially it shows me 0, but after couple of minutes it updates to the correct value. Doing a direct cast call shows the updated value immediately, however. Any idea why this lag exists on the frontend ?

[rjdat]

These request failed logs are not for the transactions you process on the front-end, but it is some internal calls that Foundry is making to get some information.

RPC request failed:
    Request: EthCall(WithOtherFields { inner: TransactionRequest { from: None, to: Some(Call(0xe7f1725e7734ce288f8367e1bb143e90bb3f0512)), gas_price: None, max_fee_per_gas: None, max_priority_fee_per_gas: None, max_fee_per_blob_gas: None, gas: None, value: None, input: TransactionInput { input: None, data: Some(0x01ffc9a780ac58cd00000000000000000000000000000000000000000000000000000000) }, nonce: None, chain_id: None, access_list: None, transaction_type: None, blob_versioned_hashes: None, sidecar: None, authorization_list: None }, other: OtherFields {} }, Some(0x2), None, None)
    Error: Execution error: execution reverted

So should we just consider this as a bug in foundry and move on then ? If you know of some other local blockchain tool, you might be able to test for such errors over there to get more clarity.

[EngrPips]

These request failed logs are not for the transactions you process on the front-end, but it is some internal calls that Foundry is making to get some information.

RPC request failed:
    Request: EthCall(WithOtherFields { inner: TransactionRequest { from: None, to: Some(Call(0xe7f1725e7734ce288f8367e1bb143e90bb3f0512)), gas_price: None, max_fee_per_gas: None, max_priority_fee_per_gas: None, max_fee_per_blob_gas: None, gas: None, value: None, input: TransactionInput { input: None, data: Some(0x01ffc9a780ac58cd00000000000000000000000000000000000000000000000000000000) }, nonce: None, chain_id: None, access_list: None, transaction_type: None, blob_versioned_hashes: None, sidecar: None, authorization_list: None }, other: OtherFields {} }, Some(0x2), None, None)
    Error: Execution error: execution reverted

So should we just consider this as a bug in foundry and move on then ? If you know of some other local blockchain tool, you might be able to test for such errors over there to get more clarity.

Yes, the error is not something to be overly concerned about.

[EngrPips]

Your cast call seems off for me, are you not supposed to pass in a uint256 such as 0, 1 or so as the argument why did you pass in 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266?

cast call 0xe7f1725E7734CE288F8367e1Bb143E90bb3F0512 "getFunder(uint256)" 0xf39Fd6e51aad88F6F4ce6aB8827279cffFb92266 --rpc-url $RPC_URL --account anvil

@EngrPips Thanks for pointing that out, actually. I took another look at it, and cast seems to be working fine at recording txns from the frontend, although that RPC request failed still exists.

Also, I noticed when I click Get Balance on the frontend after Buy Coffee, initially it shows me 0, but after couple of minutes it updates to the correct value. Doing a direct cast call shows the updated value immediately, however. Any idea why this lag exists on the frontend ?

Yeah, the front-end kind of lags. I think that is because the console is returning a cached value before a new state is fetched and cached, but maybe I am wrong. Patrick mentioned the lagging of the front-end in the course, and he didn't worry too much about it so I think you don't need to sweat over it, except if you really want to start research to find out what is causing the lag.

[rjdat]

That's true, but if I want to professionally push a frontend for a blockchain backend, i wouldn't want any lag to exist. Are there any strategies to get around this ?

Patrick mentioned something like "it takes some time to push a block forward". Can we do something similar to the cheatcodes in foundry like vm.roll(), to manually kill the lag ?

[EngrPips]

That's true, but if I want to professionally push a frontend for a blockchain backend, i wouldn't want any lag to exist. Are there any strategies to get around this ?

Patrick mentioned something like "it takes some time to push a block forward". Can we do something similar to the cheatcodes in foundry like vm.roll(), to manually kill the lag ?

I am sure there must be something that can be done to prevent that lag, but I don't know what it is. If you are willing to take on research on it then you will find interesting things.