Ethers.js throws other errors then expected by write function and read function works as expected (Solidity custom errors)

[fabioeletto]

I am building a smart contract which is deployed to the telos evm test-network. I am using custom errors in my contract for read and write functions.

Read

function getMyNumber() public view returns (uint256) {
   if(myNumber == 0) {
      revert NumberNotSet(myNumber);
   }
   return myNumber
}

Write

function setMyNumber(uint256 number) public {
   if(number > 10) {
      revert NumberToHigh(number);
   }
   myNumber = number;
}

If i call the read function from ethers with the following code everything works as expected (i'll receive my custom error with the args)

async readContractAction(
    contractAddress: string,
    functionName: string,
    ...args
  ) {
    const contract = await this.getContract(contractAddress);
    if (contract === undefined) {
      throw new NotFoundException(
        'No contract with the given address could be found!',
      );
    }
    try {
      return await contract[functionName](...args);
    } catch (err) {
      console.log('ERROR', err);
      throw new BadRequestException(
        `Function responded with an error: ${err.args} - ${err.errorName}`,
      );
    }
  }

If I want to call the write method with e.g. 11 as parameter I would expect that I'll receive my created custom error because the given number is to high.
But I get some weird errors invalid length for gasLimit, estimateGas: invalid BigNumber string, cannot estimate gas; transaction may fail or may require manual gas limit. But If I add the gas limit manually as the error pointed out, I'll get an other error message Transaction reverted: function selector was not recognized

Ethers.js write action code:

async writeContractAction(
    contractAddress: string,
    functionName: string,
    ...args
  ) {
    const contract = await this.getContract(contractAddress);
    if (contract === undefined) {
      throw new NotFoundException(
        'No contract with the given address could be found!',
      );
    }
    try {
      const tx = await contract[functionName](...args);
      await tx.wait();
      console.log('SUCCESS', tx);
    } catch (err) {
      console.log('ERROR', err);
    }
  }

If I change the revert statement in the setMyNumber function to a require statement like this, I'll get the expected error and the error reason.

function setMyNumber(uint256 number) public {
   require(number <= 10, "number to high")
   if(number > 10) {
      revert NumberToHigh(number);
   }
   myNumber = number;
}

I don't understand what I'm missing and I was wondering if there is an known pattern to handle such custom errors in ethers.js

[ricmoo]

The invalid length error is weird and maybe specific to your telos chain; I’m not sure what that means.

The unpredictable gas limit means the transaction will fail and my guess is the unrecognized selector is why it is failing; are you sure you are waiting until the contract is deployed and contacting the correct contract? You can try decompiling yourself contract and make sure the selector exists in the jump table.

This is almost certainly caused by an artifact file not being updated, the wrong contract address being used or the contract not being deployed yet (although in this last case, I’d expect a different error, unless telos is selector-aware, but I’m not aware of any chain with such a specific error detection).

[fabioeletto]

In the example above I used the following rpc url for telos evm test net: https://testnet.telos.net/evm
So my write setMyNumber function works absolutely fine until i trigger a revert, so for example try to store a number that is greater then 10. For the numbers 0 - 9 everything works as expected. My read getMyNumber function works fine in any case. It doesn't matter if I trigger an revert I always get either the number if it is not "0" or my created custom error. So my contract is deployed and I am enter the correct contract address otherwise no function would work but as I said only the write functions throws such errors but only if I trigger a revert.
I also copied my contract in remix and deployed it to different test nets:

• Injected Web3 (Telos evm testnet ) -> write function with revert error throws the mentioned weird errors
• Rinkeby -> reverted correct error as expected

That was the reason why I was asking the question the other discussion.

[poplexity]

Hey @Fabio-GitHub25 I just came across this issue debugging something on Telos EVM and tracked down the fact that "Transaction reverted: function selector was not recognized" is incorrect and could be any number of revert causes, this error comes from the RPC trying to generate meaningful error responses.

My comment in the code (I wrote most of the EVM & RPC) was that I borrowed the logic from hardhat error responses, but in my case the cause was not function selector related so I've removed that incorrect error message and updated the testnet RPC if you want to try again.

This error feels familiar so I may have already spoken with you and helped sort it out, but if not feel free to DM me on telegram foflexity and we'll figure it out :).

Hopefully this issue can be closed for the ethers folks, I <3 ethers and use it all the time, thank you!