web3 get_transaction get_transaction_receipt how to see the error-Message for a failed transaction

Question

I am using the web3-implementation from python (web3.py) and use the both methods get_transaction and get_transaction_receipt to lookup failed transactions. If the status-field from get_transaction_receipt is 0, i know the transaction has failed.

But if i lookup the transaction with etherscan (or bscscan) i see an error-message (for example: "Fail with error 'Return amount is not enough'".

How can i lookup the transaction with web3 to get access to the content of the error message?

Answer 1

As per the current scenario, web3.py doesn't handle this very well, this due to differnt clients handle RPC response in differnt ways (see this issue). However, this is being worked upon very actively (see this issue).

There are few workarounds to accomplish this:

• use eth-brownie, TransactionReceipt.revert_msg will give the verbose message for revert and TransactionReceipt.dev_revert_msg allows customization for developer specified revert comment

• use raw RPC call and parse the json

Answer 2

You can also use Tenderly API to do it, here is a sample:

GET https://api.tenderly.co/api/v1/public-contract/{chainId}/tx/{txHash}

Set the chain id and transaction hash in the request path.

By calling this API, you could check the failure reason in the error_message field or in the stack_trace[i].error

Here is a sample failed transaction:

https://polygonscan.com/tx/0x7473494c4d6ac6976193f67e624dbd0963a321dc883ea8d90e115f5246a3b6d2

As it is polygon and polygon chain id is 137, you could call this API like this:

curl 'https://api.tenderly.co/api/v1/public-contract/137/tx/0x7473494c4d6ac6976193f67e624dbd0963a321dc883ea8d90e115f5246a3b6d2' \
      -H 'authority: api.tenderly.co' \
      -H 'accept: application/json, text/plain, */*' \
      -H 'accept-language: fa,en-US;q=0.9,en;q=0.8,es;q=0.7' \
      -H 'origin: https://dashboard.tenderly.co' \
      -H 'referer: https://dashboard.tenderly.co/' \
       --compressed

This is the API response:

{
  "hash": "0x7473494c4d6ac6976193f67e624dbd0963a321dc883ea8d90e115f5246a3b6d2",
  "error_message": "ERC20: transfer amount exceeds balance",
  ...
}