BUG: segfault on exit

[tylerjereddy]

This is clearly visible in recent CI logs like the Linux pytest run here: https://github.com/yuxuanzhuang/ggmolvis/actions/runs/12759069444/job/35562217197

Also reproducible on latest main branch on ARM Mac locally with:

• python -m pip install -v .
• pytest -n 2

<snip>
============================================================================ 25 passed, 3 xfailed, 2 warnings in 4.07s ============================================================================
/Users/treddy/python_venvs/py_311_mda_dev/lib/python3.11/site-packages
2025-02-22 20:30:20.799 | DEBUG    | ggmolvis:<module>:50 - Blend file stored at /var/folders/5_/hm0ft57n6dn2ksgg2p0bx5h0000w2g/T/ggmolvis.blend
2025-02-22 20:30:22.019 | DEBUG    | ggmolvis.ggmolvis:__new__:85 - Creating new GGMolVis
Read blend: "/var/folders/5_/hm0ft57n6dn2ksgg2p0bx5h0000w2g/T/ggmolvis.blend"
zsh: segmentation fault  pytest -n 2

Can also be reproduced with a simple import Python script:

import ggmolvis

2025-02-22 20:35:50.010 | DEBUG    | ggmolvis:<module>:50 - Blend file stored at /var/folders/5_/hm0ft57n6dn2ksgg2p0bx5h0000w2g/T/ggmolvis.blend
2025-02-22 20:35:50.336 | DEBUG    | ggmolvis.ggmolvis:__new__:85 - Creating new GGMolVis
Read blend: "/var/folders/5_/hm0ft57n6dn2ksgg2p0bx5h0000w2g/T/ggmolvis.blend"
zsh: segmentation fault  python probe.py

Importing molecularnodes and bpy in isolation does not segfault of course.

I suspect others have noticed this since it consistently happens at control flow exit, but it may not be a priority since it seems you can otherwise do the work you need just fine beforehand.

[BradyAJohnston]

This is unfortunately a known issue to do with bpy compiled as a python module: https://projects.blender.org/blender/blender/issues/131922

It only happens on exit. It's mostly only problematic for pytest runs that leads to a failed run even if all tests pass.

In Molecular Nodes I run pytest internally inside Blender itself using a script instead of using bpy installed from pip as it avoids the error message on cleanup: https://github.com/BradyAJohnston/MolecularNodes/blob/main/.github/workflows/tests.yml

[BradyAJohnston]

I just ran some tests and it seems to be fixed in the Blender 4.4 (built my own 4.4 bpy and pytest doesn't crash on exit. Blender 4.4 is planned for mid-March release (https://projects.blender.org/blender/blender/milestone/24) so after that it should be resolved.

[tylerjereddy]

Thanks Brady, good to know. I guess we can leave this open until mid-March or so for visibility.

I'll poke around at something else for now then.

[tylerjereddy]

bpy 4.4.0 was released 3 days ago and indeed no longer causes the crash as noted at #39 (comment), so I'm happy to close this.