This tracking issue aims to collect all the issues and PRs related for the upcoming free-threaded CPython 3.13 (a.k.a. "no-GIL") builds. Until now, as of #7463 all the test suite is passing.

Right now, as per #7463 (comment), there are no concurrency tests for scikit-image. Mainly, such tests should target functions or classes that declare shared state constructs that may mutate under concurrent access.

We invite the community and maintainers with extensive knowledge of the project to highlight the existence of any potential thread-safety issues that currently exist.

Here are some resources that might be useful in the context of free-threaded Python

• PEP 703
• Corresponding tracker in NumPy: ENH: Support free-threaded python build (tracking issue) numpy/numpy#26157
• Corresponding tracker in SciPy: Tracker: Support free-threaded CPython builds scipy/scipy#20669
• Corresponding tracker in Pillow: Python 3.13 free-threading compatibility python-pillow/Pillow#8199
• Corresponding tracker in Pandas: ENH: Python 3.13 free-threading support pandas-dev/pandas#59057
• Free-threaded Python community Wiki: https://py-free-threading.github.io/

Pull Requests

• Add CI to test scikit-image against free-threaded Python 3.13 #7463
• Add CI to release nightly free-threaded wheels #7481
• Build cp313t linux wheels #7575