Closed
Description
Bug report
Bug description:
Currently, running the Python interpreter with -S (disabling the site module initialization) causes several inconsistencies sysconfig.get_paths() depends on whether sysconfig was imported before or after the site initialization
Currently, sysconfig calculates the paths at import time and caches them. This results in it resulting incorrect paths if the site initialization happens after sysconfig was imported.
$ python -S
Python 3.14.0a1+ experimental free-threading build (heads/main:de0d5c6e2e1, Oct 23 2024, 15:37:46) [GCC 14.2.1 20240910] on linux
>>> import sysconfig
>>> sysconfig.get_paths()
{'stdlib': '/usr/local/lib/python3.14t', 'platstdlib': '/usr/local/lib/python3.14t', 'purelib': '/usr/local/lib/python3.14t/site-packages', 'platlib': '/usr/local/lib/python3.14t/site-packages', 'include': '/usr/local/include/python3.14td', 'platinclude': '/usr/local/include/python3.14td', 'scripts': '/usr/local/bin', 'data': '/usr/local'}
>>> import site
>>> site.main()
>>> sysconfig.get_paths()
{'stdlib': '/usr/local/lib/python3.14t', 'platstdlib': '/usr/local/lib/python3.14t', 'purelib': '/usr/local/lib/python3.14t/site-packages', 'platlib': '/usr/local/lib/python3.14t/site-packages', 'include': '/usr/local/include/python3.14td', 'platinclude': '/usr/local/include/python3.14td', 'scripts': '/usr/local/bin', 'data': '/usr/local'}Expected output when the site module has been initialized:
$ python
Python 3.14.0a1+ experimental free-threading build (heads/main:de0d5c6e2e1, Oct 23 2024, 15:37:46) [GCC 14.2.1 20240910] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sysconfig
>>> sysconfig.get_paths()
{'stdlib': '/usr/local/lib/python3.14t', 'platstdlib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t', 'purelib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t/site-packages', 'platlib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t/site-packages', 'include': '/usr/local/include/python3.14td', 'platinclude': '/usr/local/include/python3.14td', 'scripts': '/home/anubis/.virtualenvs/test-sysconfig-paths/bin', 'data': '/home/anubis/.virtualenvs/test-sysconfig-paths'}And just to make sure this is not dependent on the interpreter being run with -S, and rather on the sysconfig import time.
$ python -S
Python 3.14.0a1+ experimental free-threading build (heads/main:de0d5c6e2e1, Oct 23 2024, 15:37:46) [GCC 14.2.1 20240910] on linux
>>> import site
>>> site.main()
>>> import sysconfig
>>> sysconfig.get_paths()
{'stdlib': '/usr/local/lib/python3.14t', 'platstdlib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t', 'purelib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t/site-packages', 'platlib': '/home/anubis/.virtualenvs/test-sysconfig-paths/lib/python3.14t/site-packages', 'include': '/usr/local/include/python3.14td', 'platinclude': '/usr/local/include/python3.14td', 'scripts': '/home/anubis/.virtualenvs/test-sysconfig-paths/bin', 'data': '/home/anubis/.virtualenvs/test-sysconfig-paths'}CPython versions tested on:
3.9, 3.10, 3.11, 3.12, 3.13, 3.14
Operating systems tested on:
Linux
Linked PRs
- GH-126789: fix some sysconfig data on late site initializations #126812
- [3.13] GH-126789: fix some sysconfig data on late site initializations #126918
- [3.12] GH-126789: fix some sysconfig data on late site initializations #126919
- gh-126789: Correct sysconfig test exclusions for iOS and Android. #126941
- [3.13] gh-126789: Correct sysconfig test exclusions for iOS and Android. (GH-126941) #126950
- [3.12] gh-126789: Correct sysconfig test exclusions for iOS and Android. (GH-126941) #126959
- GH-126789: fix some sysconfig data on late site initializations #127729