[ISSUE] bb verify --zk fails on proofs generated with --zk when using Poseidon2 oracle hash

[qin068]

What are you trying to do?

When I using bb with the --zk flag and --oracle_hash poseidon2 (or do not add any -- oracle_hash tag, as it is the default), I observed an inconsistent behavior between bb verify with and without --zk:

• bb prove ... --zk
  • `bb verify ... : verification succeeds
• bb prove ... --zk
  • `bb verify ... --zk: verification fails

This is not a big bug, but I feel a bit confused because it seems counterintuitive, because It is possible to run two commands with -- zk at the same time when using the --oracle_mash keccak command. I think when two tags are added at the same time under oracle_hash poseidon2 (or default), it should be able to pass validation. This looks like a small CLI / configuration inconsistency, but it is quite surprising in practice.

Code Reference

bb verify --scheme ultra_honk -p target/proof -k target/vk -i target/public_inputs --zk

Aztec Version

0.87.0

OS

Linux

Browser (if relevant)

No response

Node Version

No response

Additional Context

There is another related small issue:
When I try to use --oracle_hash starknet in bb prove, I get: Invalid proving options specified in _prove. Even though starknet is mentioned as a valid option in bb prove --help. This suggests that starknet might be only partially supported or gated behind some compile-time option. If starknet is not intended to be used here yet, it might be helpful to:
hide it from the public CLI help, or
provide a clearer error message (e.g., “starknet oracle is not supported for this scheme/configuration yet”).

It may because this version has not yet arrived and implemented this feature, but as others have said, when I automatically install the new version nargo 0.15, the installer cannot find a matching bb and will report an error. Therefore, I had to downgrade nargo to the stable version 0.9 and install the corresponding 0.87.0 version bb. I hope you can consider solving these small problems when implementing the new version. Thank you!