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Lucas Chess R freezes when adding ShashChess 39.1 engine (works fine in other GUIs) #221

@kosklod

Description

@kosklod

After compiling ShashChess 39.1 on Debian 13 (using make -j build ARCH=x86-64-ssse3 COMP=clang), the engine works correctly in terminal and in other GUIs such as Scid vs PC and PyChess.
However, when I try to install it as a new engine in Lucas Chess R, the GUI freezes immediately with the message:

lucaschessgui.pyc not responding

I waited several minutes but nothing happens.
The same setup with ShashChess 39.0 works perfectly — only version 39.1 causes the freeze.

⚙️ Steps to reproduce:

Debian 13 (64-bit)

Lucas Chess R (latest version, clean install)

Add engine: /path/to/shashchess-39.1

Wait → GUI freezes

🧠 Additional info:

The engine runs perfectly standalone:

./shashchess-39.1 uci
...
uciok

Other GUIs (Scid vs PC, PyChess) recognize the engine normally.

Possibly related to larger UCI output in version 39.1 compared to 39.0.

No crash logs appear unless Lucas is run from terminal (then the message "Not responding" shows).

✅ Workaround:

Using version ShashChess 39.0 instead of 39.1 allows normal operation in Lucas Chess R.

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