[Python] Add support and wheels for Python 3.15

[AlenkaF]

Describe the enhancement requested

It is still early but we could try adding support for Python 3.15 with the Python 3.15.0 alpha 1. See 3.15.0 schedule

Related issue: #47823 and comment.

Component(s)

Python

[paultiq]

Is there a way to setup the build so that a 3.15 failure doesn't fail the entire nightly?

[AlenkaF]

Good question.
Looking at python_wheel_xlinux_build.sh, for example, the wheels seem to be built on PyArrow main and that should have the PyWeakref_GET_OBJECT fix (if that is what you had in mind with 3.15 failure). @raulcd please correct me if I am wrong.

[raulcd]

Is there a way to setup the build so that a 3.15 failure doesn't fail the entire nightly?

I am not sure I understand the question. The different jobs for the nightlies are isolated. One job failing does not affect the others. If a Python 3.15 job would fail the rest of our Python CI nightly jobs won't be impacted. If the question wasn't about other jobs but for the specific Python 3.15 job if a test fails to continue this will depend on the failure, if the failure is a segfault when running a test or a build we won't be able to continue if it's a normal test failure we still keep running the rest of the tests.

[raulcd]

By the way, I think is a good idea and we could try to have a job with this, probably start with a minimal one as we might have issues with building other Python dependencies (pandas? numpy?)

[paultiq]

I was really asking whether a 3.15 failure would 'fail' the entire nightly. If not, great.

[paultiq]

If I'm looking at this right, the changes needed are fairly modest.

* I assumed more work would be needed on the test cases, but it looks like the appropriate logic is in place to tolerate (skipif) missing CFFI and/or Pandas.

• dev/tasks/tasks.yml: add cp315/315t
• python/requirements-wheel-build.txt: numpy 2.3.5 doesn't have a 3.15 wheel, but built from source fine (nothing special needed, just pip installed it), so no changes are needed.
• python/requirements-wheel-test.txt and python/requirements-test.txt: add markers for cffi & pandas ; python_version < "3.15"

I didn't build all the extensions, but the ninja-release-python preset built and tested fine: no pytest failures.

[raulcd]

Thanks @paultiq !
If you want to submit a PR I am happy to help reviewing and/or guiding if there's something missing.