Crash when loading state from history with changed MAT keys

[n1tr0-5urf3r]

Description

Adding key fields to an existing MAT in an existing P4 program crashes the frontend if a previous state with table entries is loaded from the history.

Steps to reproduce

1. Develop P4 program with a MAT of key field A
2. Compile P4 program and load onto switch in UniCorn-P4
3. Add table entries and save the configuration state
4. Modify P4 program: Extend MAT with key field B
5. Recompile P4 program
6. Re-initialize previously saved state
7. Switch initialization fails because existing table entries do not match to the modified MAT structure

Suggested solution

Do not write existing table entries to switch if the MAT structure changed. This should be indicated to the user in some way.

Traceback

There was an error during the initialization!Failed to initialize Switch. GRPC Connection is not available: <_InactiveRpcError of RPC that terminated with: status = StatusCode.UNKNOWN details = "" debug_error_string = "UNKNOWN:Error received from peer {created_time:"2024-11-02T11:42:58.360296778+00:00", grpc_status:2, grpc_message:""}" >

[n1tr0-5urf3r]

Maybe fixed in 7329e34