Set python_version and fix uppercase builtins

[christianbundy]

Problem

When upgrading to Mypy 1.4 (#1572) I added a setting to force uppercase builtins to ensure that tests would pass. In a comment I highlighted that we may not be able to remove this setting without changing python_version otherwise tests would only pass on some versions of Python.

I tried setting python_version = 3.8, but that caused test failures. Candidly, I didn't take very much time to investigate these.

Solution

Configure python_version = 3.11 to match our highest supported Python version, and fix uppercase builtins. I can fix the union types in a future PR, but I want to keep this one as minimal as possible. If this is the direction we want to go, we can merge this PR, but I'm open to other options.

[christianbundy]

Hmm. This is failing locally too -- I'm not sure why.

=================================== FAILURES ===================================
_______________________ models_triple_circular_reference _______________________
/home/runner/work/django-stubs/django-stubs/tests/typecheck/fields/test_related.yml:252: 
E   pytest_mypy_plugins.utils.TypecheckAssertionError: Invalid output: 
E   Actual:
E     ...
E     main:3: error: "User" has no attribute "profile" (diff)
E     main:3: note: Revealed type is "Any"          (diff)
E   Expected:
E     ...
E     main:3: note: Revealed type is "myapp.models.profile.Profile" (diff)
E   Alignment of first line difference:
E     E: main:3: note: Revealed type is "myapp.models.profile.Profile"
E     A: main:3: error: "User" has no attribute "profile"
E                ^

[intgr]

Note that show_error_codes = false also exists here as legacy, and should be fixed eventually.

You can move it below the # TODO comment you have added.

[intgr]

Thanks for the effort and sorry that this PR has languished without review for so long. Clearly there is room for improvement in how we handle PRs.

[intgr]

python_version also determines the value of sys.version_info used when interpreting typeshed stubs (for conditionals such as https://github.com/python/typeshed/blob/main/stdlib/typing.pyi#L93-L113)

So if we override this setting, we lose test coverage with different variations of typeshed definitions, and would no longer catch subtle compatibility issues in CI.

I very much prefer the modern formatting of types in error messages, but still I would err on the side of caution and prioritize test coverage here.

I wish mypy had a way to override force_uppercase_builtins in the opposite direction, e.g. force_lowercase_builtins = true. Maybe they would be willing to entertain such a PR if someone is interested doing the work. And same for force_union_syntax.

[sobolevn]

Yes, I agree - we cannot touch python_version :(