_typeshed.structseq: Use Final instead of ClassVar#6825
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As discussed in python#6816, for some `structseq` classes these attributes are writeable `ClassVar`s, but for other classes, they're read-only `ClassVar`s. Either way, however, it's probably a bad idea to be modifying these attributes, so it makes sense to simply annotate them with `Final` rather than `ClassVar`. Note that [PEP 591](https://www.python.org/dev/peps/pep-0591/) specifically states: > Type checkers should infer a final attribute that is initialized in a class body as being a class variable. Variables should not be annotated with both ClassVar and Final. As such, annotating these attributes as `Final[ClassVar[int]]` would be neither necessary nor possible.
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Cc. @Akuli |
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According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
Akuli
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Jan 5, 2022
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I'm a bit surprised that Final in a class makes the member implicitly ClassVar, but it seems to work.
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There's probably a lot of other things where we aren't using |
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As discussed in #6816, for some
structseqclasses these attributes are writeableClassVars, but for other classes, they're read-onlyClassVars. Either way, however, it's probably a bad idea to be modifying these attributes, so it makes sense to simply annotate them withFinalrather thanClassVar.Note that PEP 591 specifically states:
As such, annotating these attributes as
Final[ClassVar[int]]would be neither necessary nor possible.