Catching custom errors with nested calls

[gagiuntoli]

Related to this question, is it possible with ethersjs to catch custom errors in a situation like this:

error InvalidNumber();

contract A {
    function callB(address _address) public {
        B(_address).customError();
    }
}

contract B {
    uint256 number;
    function customError() public {
        number = 1;
        revert InvalidNumber();
    }
}

where I call callB on contract A?

The problem with callStatic is that when I do await a.callStatic.callB(), the A's ABI has no idea about the B and its custom errors, so it cannot identify the error code returned and translate into something readable.

[ricmoo]

You can add ABIs together, so as long as you include the "error InvalidNumber()" fragment in the ABI, it will be able to parse it out. :)

[gagiuntoli]

Thank you, it sounds like a good solution. Do you think it is also a good solution if I create an interface with ALL the errors of ALL the contracts and inherit the interface on every one of them? In the end, the compiler would include every custom error on every ABI. E.g.:

interface Errors {
   error customErrorA();
   error customErrorB();
}

contract A is Errors {
    function foo() {
         revert customErrorA();
    }

    function callB(address _addressB) {
         B(_addressB).bar()
    }
}

contract B is Errors {
    function bar() {
         revert customErrorB();
    }
}

[zemse]

Do you think it is also a good solution if I create an interface with ALL the errors of ALL the contracts and inherit the interface on every one of them? In the end, the compiler would include every custom error on every ABI.

There just might be a lot of non-relevant errors being included in all the contracts ABI. I think a neat solution would be to keep only relevant errors & events on the solidity level (despite the fact that the compiler would not add bytecode for unused errors or events). On the interfacing level, while constructing the ethers.Contract object you may copy the events and errors of all the contracts that the parent contract interacts with (makes a call to). It involves some work. I wish there was a tool that would do that easily. I came across some projects that do this (e.g. this). But if you are short on time, feel free to do it on the solidity level.