Enable flake8-pyi's Y037

[AlexWaygood]

Always use PEP 604 syntax instead of Union and Optional.

Closes#4819

[github-actions]

According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉

[JelleZijlstra]

beautiful

[Avasam]

I was looking forward to this one. There's still a mention to using Optional and Union as a workaround in CONTRIBUTING.md though: https://github.com/python/typeshed/blob/main/CONTRIBUTING.md?plain=1#L438

use X | Y instead of Union[X, Y] and X | None, instead of
Optional[X], except when it is not possible due to mypy bugs (type aliases and base classes);

[intgr]

types-requests version 2.28.11.11 somehow causes issues with lots of djangotestframework-stubs CI tests. (https://github.com/typeddjango/djangorestframework-stubs/actions/runs/4114959794/jobs/7103023727)

According to changelog this PR was the only change in that version.

Errors like this appear in every tests:

requests-stubs/sessions.pyi:80: error: Type application has too many types (1 expected) (diff)
requests-stubs/sessions.pyi:81: error: Type application has too many types (1 expected) (diff)
requests-stubs/sessions.pyi:99: error: Type application has too many types (1 expected) (diff)
requests-stubs/sessions.pyi:106: error: Type application has too many types (1 expected) (diff)
urllib3-stubs/fields.pyi:6: error: Type application has too many types (1 expected) (diff)

[AlexWaygood]

@intgr do your tests run with mypy 1.0? If not, you may need to upgrade to mypy 1.0.

[AlexWaygood]

That error message comes from python/mypy#11098, but that bug should have been fixed in mypy 1.0.

[intgr]

Created issue #9690. Sorry, should have done that in the first place.