catch custom error

[novaknole]

I am using 5.5.2v.

my contract:

contract Storage {
    uint public x = 10;

    error seriouserror();

    function mint2() public {
        if(5 < 10) revert seriouserror();
        x = 20;
    }
}

ABI in javascript:

[
`function mint2() public`,
`error seriouserror()`,
]

Now, when I call mint2, what I get is execution reverted and it doesn't include seriouserror..

try {
        await sponsorContract.mint2()
    }catch(err){
        console.log(err)
    }

err prints the following:

Error: cannot estimate gas; transaction may fail or may require manual gas limit (error={"code":-32603,"message":"execution reverted","data":{"originalError":{"code":3,"data":"0xbd3bb1d9","message":"execution reverted"}}}, method="estimateGas", transaction={"from":"0x94C34FB5025e054B24398220CBDaBE901bd8eE5e","to":"0x1d3d2b2e4FD22252C42Ab8c9ed33cbF7E8F1EBC5","data":"0x85d1ef63","accessList":null}, code=UNPREDICTABLE_GAS_LIMIT, version=providers/5.5.2)
at Logger.makeError (index.ts:225:1)

Seems like i can't get seriouserror thing... Any idea ?

[zemse]

I am able to reproduce this on 'ethers/5.6.8'. Will get back to you on this soon.

[steven2308]

This is the only thing that worked for me on ethers 5.6.8. No idea why the error data is in such a different location.

try {
  await myContract.someMethod()
} catch (error) {
  // @ts-ignore
  const revertData = error.data.data
  const decodedError = myContract.interface.parseError(revertData)
  console.log(`Transaction failed: ${decodedError.name}`)
}

[kabaluyot]

Thanks! Looks good tho the error might look different on other rpcs

[superical]

Thanks! Looks good tho the error might look different on other rpcs

@kabaluyot I'm curious which other RPCs might have a different error?

[kabaluyot]

Avalanche RPCs return different error format vs Eth RPCs when I did error catching.
Even the error that @steven2308 wrote is different to original answer.

[superical]

I have created a utility https://github.com/superical/ethers-decode-error to simplify the process of getting custom errors. If anyone happens to use the library with Avalanche or other RPCs, please let me know if it works or not, and I can update the library to handle those RPCs too.

[3commascapital]

i have started to write a hardhat plugin to help with this issue, and the class is standalone, though i have never used it as such yet. feel free to contribute
https://github.com/3commascapital/hardhat-vizor

[superical]

I found myself going back to this problem repeatedly for some reason. I have decided to solve this custom error issue for good with a utility. Anyone interested can find the utility here as well: ethers-decode-error

This utility library helps with extracting the actual revert error messages, and catching custom errors and their arguments from the smart contracts. Just pass in the error and you will get the custom error and its arguments (if any). Hopefully this helps anyone who is also having the same problem.

[gsteenkamp89]

Absolute legend 👏

[6be709c0]

In ethers V6:

} catch (e) {
    if (e.data && contract) {
      const decodedError = contract.interface.parseError(e.data);
      console.log(`Transaction failed: ${decodedError?.name}`);
    } else {
      console.log(`Error:`, e);
    }
  }

[lxiiiixi]

There are also a parse function in ethers v5 to parse custom error.
https://docs.ethers.org/v5/api/utils/abi/interface/#Interface--parsing