Update loky to 3.5.1.

[trivialfis]

macos hang https://github.com/dmlc/xgboost/actions/runs/13872185297/job/38820191876 .
mgpu test error: https://github.com/dmlc/xgboost/actions/runs/13898762098/job/38886026698?pr=11339

Ref dmlc/xgboost-devops#15 .

[hcho3]

Still getting the same error in mgpu?

[trivialfis]

Need to freeze CPU env as well.

[trivialfis]

It seems I couldn't freeze loky on CPU CI:

2025-03-18T07:41:51.2845518Z 
2025-03-18T07:41:51.2845721Z =================================== FAILURES ===================================
2025-03-18T07:41:51.2846380Z ___________________________ test_rabit_communicator ____________________________
2025-03-18T07:41:51.2846861Z 
2025-03-18T07:41:51.2847019Z     @pytest.mark.skipif(**tm.no_loky())
2025-03-18T07:41:51.2847538Z     def test_rabit_communicator() -> None:
2025-03-18T07:41:51.2848015Z         import loky
2025-03-18T07:41:51.2848395Z         from loky import get_reusable_executor
2025-03-18T07:41:51.2848853Z     
2025-03-18T07:41:51.2849167Z >       assert loky.__version__ == "3.4.1"
2025-03-18T07:41:51.2849892Z E       AssertionError: assert '3.5.0' == '3.4.1'
2025-03-18T07:41:51.2850319Z E         
2025-03-18T07:41:51.2850582Z E         - 3.4.1
2025-03-18T07:41:51.2850860Z E         + 3.5.0
2025-03-18T07:41:51.2851043Z 
2025-03-18T07:41:51.2851564Z tests/python/test_collective.py:30: AssertionError

[trivialfis]

Found the definition in the devop repo. Will freeze loky there. We need a way to unify the dependencies between the main repo and the devop repo.

[trivialfis]

cc @hcho3 All tests pass.

[jakirkham]

JFYI loky just released 3.5.1

Maybe worth testing if that fixed the issue

[trivialfis]

Thank you for sharing! We still need a conda update before we can use it on CI.

[trivialfis]

conda-forge/loky-feedstock#28

[jakirkham]

Should be available now

xref: conda-forge/loky-feedstock#31

[trivialfis]

Updated to loky 3.5.1. All tests pass. Thank you, @jakirkham, for sharing and the help!

[jakirkham]

Glad this is working Jiaming! 😀

Had a minor suggestion below

[jakirkham]

Instead of requiring latest, we could simply disallow the problematic version

This could also be done in setup.py and other environment files

Suggested change

	- loky>=3.5.1
	- loky!=3.5.0

[trivialfis]

Thank you for the suggestion! I think I would like to keep it as the latest for the CI, it's only used by the tests and we don't want to deal with more than one version in the CI.