[3.14] gh-144601: Avoid sharing exception objects raised in a PyInit function across multiple interpreters (GH-144602)

[miss-islington]

(cherry picked from commit fd6b639)

Co-authored-by: Peter Bierma zintensitydev@gmail.com

• Issue: Extensions that raise exceptions in their PyInit* cause a crash in subinterpreters #144601

[ZeroIntensity]

Hm, I'm very confused as to why the test is failing here, especially since this worked fine on main. I'll investigate tomorrow.

[ZeroIntensity]

Ah, found the problem. The issue is that in <3.15, there's an unused import to _testsinglephase in test_importlib.util, so import_extension_from_file can't even be imported from the subinterpreter:

cpython/Lib/test/test_importlib/util.py

Line 18 in bbd682d

_testsinglephase=import_helper.import_module("_testsinglephase")

This was removed on main by #141785, but that wasn't backported. @encukou -- I'm not familiar with _testmultiphase. Is there any reason we can't switch to also importing _testmultiphase on 3.14?

[encukou]

None that I can think of.
Sorry that I embedded that in a bigger change. I'd be happy to review a partial backport.

[miss-islington-app]

Thanks @miss-islington for the PR, and @ZeroIntensity for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @miss-islington and @ZeroIntensity, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker 907958c4ba3f310d18810f7132f1ecd6798dd5c5 3.13