Include revert data in the contract execution error types

[PaulRBerg]

Problem

There are situations where it is useful to investigate the revert data in a frontend environment, e.g., when performing a call to simulateAndRevert to check the gas consumption of a Safe tx without actually submitting that tx.

The problem is that Viem doesn't include the revert data in BaseError or any other contract interaction-related error, e.g., CallExecutionError. None of the following fields contain the revert data: cause, docsPath, metaMessages.

It is actually possible to revert the data, but that has to be done through walking the error:

const lowLevelError = callError.walk();
const revertData = lowLevelError.data;

This is really not intuitive and there's no documentation about this walk method that is available for the error types.

Our team has spent days debugging an issue that would have taken much less time if we had known about walk. And it looks like others have encountered the same issue, too.

Suggested Solution

Make the revert data available in the BaseError type.

Alternatively, create a new type called ExecutionError with a field revertData (or just data), and make the CallExecutionError, ContractFunctionExecutionError, etc., types inherit from ExecutionError.

[jxom]

We can make data available on the roots of these error DAGs.