Ecosystem.decode_error() (inspired by custom Solidity error types)

Elevator pitch:

When using solidity error definitions, the revert message (the inputs to the custom error) are not decoded (they are just bytes).

e.g.

ape.exceptions.ContractLogicError: b'\x9b\x0f\x01\xda\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00;\x9a\xca\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x01'

Let's do what we do best and dynamically generate a custom Exception class with the inputs as the properties!

Value:

Solidity projects that use custom errors.

Dependencies:

https://github.com/ApeWorX/ethpm-types/pull/29#pullrequestreview-961074682

Design approach:

Like structs, events, etc, let's create custom ContractLogicError classes that have the inputs as the properties on the class

So in your solidity, if you do:

    error InsufficientFund(uint256 given, uint256 required);

    function fund() public payable isOn {
        if (msg.value > 0) {
            revert InsufficientFund(msg.value, 1);
        }
    }

, you can access the custom error classes on the ContractInstance and they will be the exceptions raised for reverts in that case.

So you can do this in your tests:

with ape.reverts(contract.InsufficientFund) as err:
    ...

assert err.value.foo == 5
assert err.value.bar == 6

Exactly like pytest.raises() works.

NOTE: The original still has to work to as not be breaking:

with ape.reverts(message="revert reason"):

Task list:

[ ] Tasks go here

Estimated completion date:

Design review:

Do not signoff unless:

1) agreed the tasks and design approach will achieve acceptance, and
2) the work can be completed by one person within the SLA. Design reviewers should consider simpler approaches to achieve goals.

(Please leave a comment to sign off)

ApeWorX / ape