recent regression with uci engine

[jdart1]

Describe the bug
after updating to the HEAD, lichess-bot fails on startup with an exception. This appears to be a recent behavior change: If I revert back to commit 616dd81, it works. Note I have filed a similar issue with python-chess (niklasf/python-chess#1049) but I believe this is a different problem, because it occurs without debug output enabled.

To Reproduce
Steps to reproduce the behavior:

1. python3 lichess-bot.py --logfile lichess.log -v with Arasan as the engine

Expected behavior
startup of engine, no exception

Logs

lichess.log

Desktop (please complete the following information):

• OS: Windows 11
• Python Version 3.10.11

[AttackingOrDefending]

lichess-bot processes debug output even if it isn't enabled, because it stores it in a file inside the lichess_bot_auto_logs folder. It just doesn't print it to the console. I couldn't reproduce this issue, probably because I didn't get the line info string out of do_all_pending, list size=0. What should I do for the engine to print this line?

What version of python-chess are you using while running HEAD and 616dd81?

[MarkZH]

The commit you revert to is before commit 26732d1. That commit causes lichess-bot to try to start the chess engine on startup as a quick check that the engine is configured correctly. When you revert to the older commit, can your engine actually play a game, or does it exit with an error?

[jdart1]

I spoke too soon: no, it doesn't actually play a game, despite not putting out any debug info (any in the log would be from an earlier run). python-chess version is 1.9.4: maybe that is the issue?

[MarkZH]

In your configuration file:

  uci_options:
    Threads: 8
    Hash: 32768
    SyzygyTbPath: /home/jdart/chess/syzygy:/home/jdart/chess/syzygy-6man/wdl:/home/jdart/chess/syzygy-6man/dtz
    debug: true

The option debug is not listed as a possible option in your engine.

 option name Hash type spin default 64 min 4 max 64000
 option name Ponder type check default true
 option name Contempt type spin default 0 min -200 max 200
 option name Use tablebases type check default true
 option name SyzygyTbPath type string default /home/jdart/chess/syzygy:/home/jdart/chess/syzygy-6man/wdl:/home/jdart/chess/syzygy-6man/dtz
 option name SyzygyUse50MoveRule type check default true
 option name SyzygyProbeDepth type spin default 4 min 0 max 64
 option name MultiPV type spin default 1 min 1 max 10
 option name OwnBook type check default true
 option name Favor frequent book moves type spin default 50 min 0 max 100
 option name Favor best book moves type spin default 50 min 0 max 100
 option name Favor high-weighted book moves type spin default 100 min 0 max 100
 option name Randomize book moves type spin default 50 min 0 max 100
 option name Threads type spin default 1 min 1 max 256
 option name UCI_LimitStrength type check default false
 option name UCI_Elo type spin default 3300 min 1000 max 3300
 option name Use NNUE type check default true
 option name NNUE file type string default arasan-d9-SFv4-20230728.nnue
 option name Move overhead type spin default 30 min 0 max 1000

The error happens because your engine does not know what to do with a debug option.

[MarkZH]

This error is from line 392 of the log you posted:

chess.engine.EngineError: engine does not support option debug (available options: Hash, Ponder, Contempt, Use tablebases, SyzygyTbPath, SyzygyUse50MoveRule, SyzygyProbeDepth, MultiPV, OwnBook, Favor frequent book moves, Favor best book moves, Favor high-weighted book moves, Randomize book moves, Threads, UCI_LimitStrength, UCI_Elo, Use NNUE, NNUE file, Move overhead)

[jdart1]

Ok, thanks.