[Bug] Empty Anonymous Events Can Decode Any Event

[cre-mer]

Component

sol-types

What version of Alloy are you on?

v1.0.38

Operating System

macOS (Apple Silicon)

Describe the bug

An empty anonymous event can decode any other event. For example:

sol! {
    event NonAnonymousLog(addres, uint256, bool);
    event AnonymousLog() anonymous;
}

// Execute a transaction that emits `NonAnonymousLog(addres, uint256, bool)` and try decoding the log with `AnonymousLog`
let anonymous_log = tx.decoded_log::<AnonymousLog>(); // This will return `Some`
assert!(anonymous.is_some()); // This will not fail

This does not work if the event has fields. For instance, event AnonymousLog(address) anonymous cannot decode other events. I assume this happens because the empty anonymous event has no topics and no data, so the checks are skipped, which is not the case for a non-empty event.

Not sure whether this behavior is expected or not, but it is not very clear and can cause confusion or bugs in tests.

[mattsse]

@cre-mer can you try decode_log_validate

@DaniPopes can't really remember the context here but we might want to add some additional docs for all of this