gh-123961: convert curses.window static type into a heap type

[picnixz]

I think this should do the job. I observed that there are more reference leaks but I think it's normal since I don't know of any way to actually clear the heap type in a single-phase initialization module.

The only way I can think of clearing it is to add some finalization callback at interpreter's shutdown but I think this is not a good idea because we'll likely transform the module into a multi-phase initialization module in the next PR.

However, I'd like to have some additional eyes (cc @encukou@Eclips4) to indeed check that the reference leaks that I introduced are inevitable and not due to how I defined the heap type.

• Issue: Refactorization of _cursesmodule.c to fix reference leaks #123961

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📚 Documentation preview 📚: https://cpython-previews--124934.org.readthedocs.build/

[vstinner]

LGTM

[picnixz]

Since I'm waiting for Kirill's review, I'll also run the build bots!

[bedevere-bot]

🤖 New build scheduled with the buildbot fleet by @picnixz for commit 9c787bc 🤖

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

[vstinner]

There is no ref leak:

$ ./python -m test test_curses -u all -R 3:3
(...)
Result: SUCCESS

[Eclips4]

LGTM. 🚀

[vstinner]

Merged, thanks.