gh-96471: Add queue shutdown

[EpicWink]

• Issue: Queue shutdown #96471

[bedevere-bot]

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Please add it using the blurb_it web app or the blurb command-line tool.

[gvanrossum]

Note that once this is ready for review we may need three separate reviewers -- one for asyncio, another for multiprocessing, a third for threading.

[YvesDup]

an example:

Suggested change

	ifself.shutdown_state!=_queue_alive:
	ifself.shutdown_stateisnot_QueueState.ALIVE:

[YvesDup]

1. I have 6 more tests for file Lib/test/test_queue.py . How to proceed to send you all these lines ? Sorry for my question but I am not familiar with git commands :-(
2. @EpicWink I do not see any shutdown method in file Lib/multiprocessing/queues.py . Can you confirm please ? But There is a close method.
   UPDATE:
   self._shutdown_state attr must be add to tuples of __setstate__ and __getstate__ in order to be included in serialization. Refers to lines 67 & 71 of Lib/multiprocessing/queues.py

[merwok]

This should help: https://devguide.python.org/getting-started/git-boot-camp/

The basic commands you will need are git add Lib/test/some/file to register changes in a file, git commit to save the registered changes with a note, git push to send the commits to your repository. The pull request will then be updated automatically.

[YvesDup]

@merwok Thank for your feedback. I created my own branch from EpicWink:queue-shutdown, and I am wondering how to give access to my changes. So may be @EpicWink can merge from YvesDup:queue-shutdown ?

[merwok]

Oh I missed that you weren’t the author of the PR!

Yes, you can make a pull request from your fork to epicwink’s work, or use the suggestion system here (comment on a line, find suggestion in the toolbar) to paste your new tests.

[YvesDup]

I read again the original topic and found nothing about what to do about the 'joined' tasks, threads (or processes). I just complete the shutdown method (only in asyncio and threading) to release them. May be it is not a good option, or a sufficient option. Should we raise a ShutDownexception for each of them ? Thoughts ?

[gvanrossum]

@YvesDup What is your definition of a "'joined' task or thread"?

[YvesDup]

@gvanrossum: Task (or thread) that has called the .join() method of Queue. It is blocked until (_)unfinished_task attribute of Queue drops to 0. "blocked" task is more appropriate in that case.

[EpicWink]

I'm reviewing @YvesDup 's changes in EpicWink#2

[YvesDup]

I have just created a new PR gh-96471: Add queue shutdown, next step. to resume and continue working on this feature

[willingc]

@YvesDup Would you like to close this PR and split up #102499 into 3 PRs? Ideally breaking out asyncio into its own PR. Thanks!

[EpicWink]

This has been superseded by #102499, then by #104225, #104228 and #104230