GeezerVison

🤖 New build scheduled with the buildbot fleet by @gpshead for commit b02aefc 🤖

Results will be shown at:

https://buildbot.python.org/all/#/grid?branch=refs%2Fpull%2F140191%2Fmerge

If you want to schedule another build, you need to add the 🔨 test-with-buildbots label again.

Should we backport this?

Warnings changes in patch releases make it harder to update, and from comments like #135427 (comment) it sounds like it's important to fix this now.

But, if you think it should get a backport, let's do it :)

I don't think this one is actually urgent to backport. I'll close this, the PR is ready and can be resurrected if deemed important.

So -Werror doesn't turn it into an error in 3.14 but we've fixed that in 3.15? good enough. This is an odd warning - it'll probably never become an error because our detection can only ever be best effort (it cannot be guaranteed to detect if other threads exist), it's more of the best way to surface an application design flaw to users.

^^; one reference point is that I ran into this new error on a test suite on 3.15, and the issue was that the test suite had -Werror and so didn't see the fork + threads thing earlier. I got very confused, since I knew the DeprecationError wasn't added in 3.15! But now I've figured it out, so no harm done.