Support python 3.14

[mraspaud]

With new handling of multiprocessing and forking, python 3.14 broke a few things in trollflow2.

This PR fixes it.

• Tests passed

[codecov]

Codecov Report

❌ Patch coverage is 91.89189% with 3 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.70%. Comparing base (bec2e28) to head (fd65f83).
⚠️ Report is 5 commits behind head on main.

Files with missing lines	Patch %	Lines
trollflow2/tests/test_launcher.py	88.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #244      +/-   ##
==========================================
+ Coverage   94.52%   94.70%   +0.18%     
==========================================
  Files          15       15              
  Lines        3379     3383       +4     
==========================================
+ Hits         3194     3204      +10     
+ Misses        185      179       -6     

Flag	Coverage Δ
unittests	94.70% <91.89%> (+0.18%)	⬆️

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[pnuu]

LGTM.

So the Manager didn't work when it was a global varible, and the cache usage fixes it?

[mraspaud]

LGTM.

So the Manager didn't work when it was a global varible, and the cache usage fixes it?

Yes, that's correct, in python >= 3.14, the process spawning method changed, so the memory context isn't shared at all between processes anymore. I older version we could provoke the error too if we change the default spawning method to "forkserver" (which is now the default).