Unexpected ABIError from benign code change

[alexghr]

Aim

I've encountered this issue doing two different things:

1. I've added an if statement in aztec-packages in order to update a field on a struct
2. I ran an "empty" transaction in aztec (a new BatchCall([])). Internally this uses if statements to only execute non-empty function calls

Expected Behavior

It should work (field should be updated in the first case/the tx should be valid in the second case)

Bug

In both instances aztec's private_kernel_init fails with an ABIError.

The first code change is here and leads to this error in CI

In the second case here's a minimal example and here's the CI run for it

In the first case we were able to find a workaround where we replaced the if statement with a "max" function and that has fixed the problem. I haven't looked for a workaround for the empty BatchCall example.

To Reproduce

Run the test in AztecProtocol/aztec-packages#5666

Project Impact

Blocker

Impact Context

A workaround was found for the first case. The second case, with the BatchCall, is contrived but realistically it should work since there's nothing wrong with it.

It's unclear what triggers the bug and what other (valid) use cases could lead to it.

Workaround

None

Workaround Description

We found this workaround for the first use case.

Additional Context

No response

Installation Method

Compiled from source

Nargo Version

No response

NoirJS Version

No response

Would you like to submit a PR for this Issue?

Maybe

Support Needs

No response

[TomAFrench]

My understanding was that Aztec was using their own abi encoder though? Is that not correct?

[TomAFrench]

@alexghr I've pushed a change which will highlight exactly which input is breaking type checks during abi encoding. Looks like your counter for note hash read requests is not a valid u32.

2024-04-12 16:42:37 end-to-end_1  |     Received promise rejected instead of resolved
2024-04-12 16:42:37 end-to-end_1  |     Rejected to value: [Error: (JSON-RPC PROPAGATED) The value passed for parameter `input.private_call.call_stack_item.public_inputs.note_hash_read_requests[0].counter` does not match the specified type:
2024-04-12 16:42:37 end-to-end_1  |     Value Field(11425886363827509554056097664977951424140858054424059518964806857959181738141) does not fall within range of allowable values for a Integer { sign: Unsigned, width: 32 }]

[alexghr]

Thanks @TomAFrench, I think this could this be related to #4600 where we were seeing corruption of the note_hash_read_requests. I'll retest the flow now that #4600 has been fixed (and there's extra debug info)

[alexghr]

Can confirm the latest changes in Noir have fixed this issue https://github.com/AztecProtocol/aztec-packages/actions/runs/8701866086/job/23865456943