gh-140729: Fix the cProfile module when the executed script contains calls to multiprocessing.Process

[YvesDup]

When profilng the ttt.py script via cProfile module ,

import multiprocessing

def worker_proc(x):
    return x ** 99

def main_proc():
    p = multiprocessing.Process(target=worker_proc, args=(10,))
    p.start()
    p.join()

if __name__ == "__main__":
    main_proc()

./python.exe -m cProfile ttt.py 

an error occurs:

AttributeError: module '__main__' has no attribute 'worker_proc'

This fix does not apply to the profile module, which is deprecated and will be removed in python 3.17.

• Issue: 3.15 profiling, can't use ProcessPoolExecutor.map() in a simple script #140729

[github-actions]

This PR is stale because it has been open for 30 days with no activity.

[YvesDup]

@aisk Could you help me about the failing test please ?

[aisk]

Thank you for the PR, LGTM!

[pablogsal]

I pushed a small fix for this. Can you take a look?

[YvesDup]

I pushed a small fix for this. Can you take a look?

I agree with the comment in _init__.py file, really more explicit.

The fix also works with the forkserverstart method. I suggest to add a dedicated test with this start method, and update the news file. Do you agree ?

EDIT: I pushed a new commit including all the forkserver start method modifications

[pablogsal]

LGTm thanks for the fix!

[miss-islington-app]

Thanks @YvesDup for the PR, and @pablogsal for merging it 🌮🎉.. I'm working now to backport this PR to: 3.13, 3.14, 3.15.
🐍🍒⛏🤖

[miss-islington-app]

Sorry, @YvesDup and @pablogsal, I could not cleanly backport this to 3.14 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker d7275d356916f839dc96aaa43a75e0bbde25732e 3.14

[bedevere-app]

GH-153243 is a backport of this pull request to the 3.15 branch.

[miss-islington-app]

Sorry, @YvesDup and @pablogsal, I could not cleanly backport this to 3.13 due to a conflict.
Please backport using cherry_picker on command line.

cherry_picker d7275d356916f839dc96aaa43a75e0bbde25732e 3.13

[YvesDup]

Because the cProfile migration, I think the backport should only affect version 3.15.

[bedevere-app]

GH-153265 is a backport of this pull request to the 3.14 branch.

[aisk]

The cProfile migration just moves the file to another location, so I found that we can backport it to 3.14 easily. The result is above.

But while trying to backport this to 3.13, I found that because #132738 was not backported to 3.13 and it changed the surrounding code, we can't simply backport the current PR.

Since 3.13 will reach end of life in around two months, I think we can just leave it as it is.