lots of swig warnings running pytest

[schaubh]

Describe the issue
When compiling with Python 3.11-3.13 and swig 4.2.1 to 4.3.1 we get lots of swig warnings when running

To reproduce
Steps to reproduce the behavior:

1. Do clean build with Python 3.13
2. run pytest -n auto src/tests/test_scenarioTest.py
3. See lots of warnings about DeprecationWarning: builtin type swigvarlink has no __module__ attribute

Expected behavior
We should not be seeing these warnings.

Desktop (please complete the following information):

• OS: macOS Tahoe
• Version 26.2
• Python version 3.11 to 3.13

[sassy-asjp]

It seems related to this swig/swig#2881 and maybe the only thing possible beyond contributing a fix to swig, would be to add a pytest filterwarnings for it

[schaubh]

When we can move to swig 4.4.x these warnings should go away. Rather irritating now now. We did recently push a branch that suppressed most of these warnings in pytest for the moment. Once we have the wheel builds working the way we need (reducing size to work better with PyPi, allowing for a plug-in wheel architecture), we will then revisit this.

@ReeceHumphreys , can we add code to a a python init file to suppress these warnings for run-time as well? I think right now we just suppress them when running pytest?

[nabelekt]

swig 4.4.1 is now in PyPI https://pypi.org/project/swig/
Edit: but I guess that's not the blocking item here

[schaubh]

Thanks, we'll check it out. The issue we were having is keeping compatibility with Python 3.8 onwards, to the best of my knowledge. This prevented us to moving to newer swig. Right now we are wrapping up large build improvements and will return to this issue after that

[nabelekt]

Thanks, we'll check it out. The issue we were having is keeping compatibility with Python 3.8 onwards, to the best of my knowledge. This prevented us to moving to newer swig. Right now we are wrapping up large build improvements and will return to this issue after that

Got it. We're on Python 3.12.3. It looks like the oldest version still receiving security updates is 3.10, so probably good to move on anyway. FWIW, with tests written for our external modules, updating swig from 4.3.1 to 4.4.1 resolved several deprecation warnings.

[schaubh]

Thanks for sharing! I agree that 3.8 is too old. We deprecated this in April 2025 and plan to remove it in April 2026. We have been giving users 1 year for all deprecations. At that time I plan to deprecate python 3.9 for the reasons you state.