fix: test setter on df.columns with pyright, not mypy

[Dr-Irv]

pyright 1.1.286 fixed an issue that didn't allow users to write df.columns = ["abc", "def"].

Our testing code was not picking this up because we had #type: ignore comments on the testing code, which are needed because of a mypy bug.

So I've instrumented the test to be checked with pyright, but not mypy. Unfortunately, mypy doesn't support a mypy: ignore comment.

• Issue reported to pyright was here: Using a setter on a property with list[TypeVar[Hashable]] reports error microsoft/pyright#4293
• Discussion on how to see which type checker is being used is here: Testing which type checker is type checking the code microsoft/pyright#4292

[twoertwein]

Does this new way of ignoring mypy-only errors allow enabling mypy's and pyright's check for unneeded ignores?

[Dr-Irv]

Does this new way of ignoring mypy-only errors allow enabling mypy's and pyright's check for unneeded ignores?

For mypy, the answer is no. See python/mypy#14365

I wanted to add a test like this:

if TYPE_CHECKING_INVALID_USAGE and not IS_TYPE_CHECKER_MYPY:
     df.columns = "abc"  # type: ignore[assignment]

but mypy still checks it. Although I guess I could use a pyright: ignore here and do that. I will try that out.

[twoertwein]

Could do something like at typeshed python/typeshed@23ac9bf Use type: ignore for only mypy and the pyright-specific codes only for pyright. I think this could be cleaner than the constant approach.

[Dr-Irv]

Could do something like at typeshed python/typeshed@23ac9bf Use type: ignore for only mypy and the pyright-specific codes only for pyright. I think this could be cleaner than the constant approach.

We currently are reporting wrong ignores with mypy. But for pyright, if we use the option reportUnnecessaryTypeIgnoreComment, we get a lot of reports. The reason is that in the PYI files, we have # type: ignore comments that are needed for mypy, but not for pyright. So the typeshed solution won't help here - we can't put something that says "ignore for mypy, but pyright should type check"

If we have a line of valid code, then I think this table summarizes things

mypy reports	pyright reports	mypy fix	pyright fix
Valid	Valid	Not needed	Not needed
Valid	Invalid	Not needed	Use #pyright: ignore
Invalid	Valid	#type: ignore	Not needed, but won't work with reportUnnecessaryTypeIgnoreComment
Invalid	Invalid	#type: ignore	#type: ignore

It's the third case that is causing issues for us to be able to use reportUnnecessaryTypeIgnoreComment with pyright

[gandhis1]

So there isn't a Mypy-only equivalent of #pyright: ignore (or a way to have Pyright disregard type: ignore)? I feel like the optimal solution would be to require separate ignores for Mypy and Pyright individually, but from the table it doesn't seem like that's even possible.

[Dr-Irv]

So there isn't a Mypy-only equivalent of #pyright: ignore (or a way to have Pyright disregard type: ignore)? I feel like the optimal solution would be to require separate ignores for Mypy and Pyright individually, but from the table it doesn't seem like that's even possible.

Unforunately, there is not a #mypy: ignore and there is a feature request here for that: python/mypy#12358