gh-141489: Simplify closure/freevar iteration in annotationlib._build_closure()

[dr-carlos]

• Issue: annotationlib: Simplify __closure__ and __code__.co_freevars access in annotationlib._build_closure #141489

[dr-carlos]

I don't think this needs a news entry since it's an internal semantics change. Technically the function can now raise an error, but as previously explained, I can't find any way to actually cause that to occur.

[dr-carlos]

Unsure as to why test_import is failing - it succeeds locally with python -m test -v test_import test_import

[JelleZijlstra]

0:07:02 load avg: 3.91 [256/497/1] test_import failed (1 failure)
test test_import failed -- Traceback (most recent call last):
  File "/home/runner/work/cpython/cpython/Lib/test/support/__init__.py", line 1327, in wrapper
    func(self)
    ~~~~^^^^^^
  File "/home/runner/work/cpython/cpython/Lib/test/test_import/__init__.py", line 3319, in test_basic_multiple_interpreters_deleted_no_reset
    self.check_copied(loaded_interp1, base)
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/home/runner/work/cpython/cpython/Lib/test/test_import/__init__.py", line 2981, in check_copied
    self.assertNotEqual(snap.id, base.snapshot.id)
    ~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 139871758231760 == 139871758231760

Wonder if it's a latent failure unrelated to this change.

[johnslavik]

Wonder if it's a latent failure unrelated to this change.

See also #141545

[miss-islington-app]

Thanks @dr-carlos for the PR, and @JelleZijlstra for merging it 🌮🎉.. I'm working now to backport this PR to: 3.14.
🐍🍒⛏🤖

[bedevere-app]

GH-141776 is a backport of this pull request to the 3.14 branch.