[pre-commit] Fix local pre-commit installation for python != 3.8

[Pierre-Sassoulas]

Refs #12868

[nicoddemus]

Thanks @Pierre-Sassoulas and @The-Compiler!

[patchback]

Backport to 8.3.x: 💚 backport PR created

✅ Backport PR branch: patchback/backports/8.3.x/2242cd43eb5601e3f282003c049e37e56ece932a/pr-12869

Backported as #12871

🤖 @patchback
I'm built with octomachinery and
my source is open — https://github.com/sanitizers/patchback-github-app.

[The-Compiler]

Might be better to set this in pyproject.toml rather than here? This should also be active when mypy is run via IDE or standalone, not just via pre-commit.

[webknjaz]

In my other projects, I started running MyPy against multiple Python versions, keeping all the shared configuration in the config and only setting the diverging options in pre-commit: https://github.com/ansible/awx-plugins/blob/0b3155e/.pre-commit-config.yaml#L188-L280 / https://github.com/ansible/awx-plugins/blob/0b3155e/.mypy.ini#L1-L58.

Listing every supported version is possible, but is probably too much, so I was doing it for every other version. To reduce the number of calls even more, it's also possible to just run against minimum and maximum supported versions…

In my example, I've also introduced per-version aliases that are useful for local development to run less things while actively fixing stuff.

I'm hoping to bring this approach to pytest one day.

[Pierre-Sassoulas]

Running against python 3.13 we have:

src/_pytest/pathlib.py:704: error: Argument 2 to "NamespaceLoader" has incompatible type "Path"; expected "MutableSequence[str]"  [arg-type]
src/_pytest/pathlib.py:704: error: Argument 3 to "NamespaceLoader" has incompatible type "PathFinder"; expected "Callable[[str, tuple[str, ...]], ModuleSpec]"  [arg-type]
src/_pytest/runner.py:170: error: Unused "type: ignore" comment  [unused-ignore]
src/_pytest/runner.py:180: error: Unused "type: ignore" comment  [unused-ignore]
testing/test_runner.py:1033: error: Unused "type: ignore" comment  [unused-ignore]

Found 5 errors in 3 files (checked 232 source files)

Some of those messages are going to be incompatible (the unused ignore is not unused in python 3.8)

[webknjaz]

Some of those messages are going to be incompatible (the unused ignore is not unused in python 3.8)

I think this is a good example of disabling the check on the CLI in just one of the invocations.

[webknjaz]

Alternatively, those could be ignored on the respective lines.

[Pierre-Sassoulas]

I'm wondering if the two errors Line 704 for python 3.13 are legit. The added complexity might be worth it if they are.

[webknjaz]

Might be better to set this in pyproject.toml rather than here? This should also be active when mypy is run via IDE or standalone, not just via pre-commit.

I usually set in two places — the minimum version goes to .mypy.ini while pre-commit adds additional versions on top. In general, I agree that the underlying tooling configs should be used whenever possible since it allows other software to pick up the same settings.

[Pierre-Sassoulas]

Might be better to set this in pyproject.toml rather than here?

Definitely, opened #12872