Allow @final on TypedDict
#13557
Allow @final on TypedDict
#13557
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| @@ -1469,8 +1469,8 @@ def analyze_typeddict_classdef(self, defn: ClassDef) -> bool: | |||
| for decorator in defn.decorators: | |||
| decorator.accept(self) | |||
| if isinstance(decorator, RefExpr): | |||
| if decorator.fullname in FINAL_DECORATOR_NAMES: | |||
| self.fail("@final cannot be used with TypedDict", decorator) | |||
| if decorator.fullname in FINAL_DECORATOR_NAMES and info is not None: | |||
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What if the info is None? Does that happen if there's a circular reference? It would be good to get a test covering that code path.
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It could be FakeInfo for some reason.
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What if the info is None? Does that happen if there's a circular reference?
When there's a forward declaration in the TypedDict body, analyze_typeddict_classdef gets called multiple times. info is initially None in that case, but eventually it's a TypeInfo.
It would be good to get a test covering that code path.
Done.
It could be
FakeInfofor some reason.
When would that happen?
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Also the CI failures look like there are some duplicate error messages. |
Allow a `TypedDict` to be decorated with `@final`. Like a regular class, mypy will emit an error if a final `TypedDict` is subclassed. Relates-to: python#7981
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That's what I get for only running the |
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Huh. This seems to be causing a mypyc segfault, judging by The mypyc tests ( |
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The segfaults may be unrelated, we're seeing them on a bunch of PRs. Not sure what's causing them :( |
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According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
Allow a
TypedDictto be decorated with@final. Like a regular class, mypy will emit an error if a finalTypedDictis subclassed.Relates-to: #7981
Description
Allow
@finalto be applied to aTypedDict, and have mypy emit an error if class is derived from a finalTypedDict. This goes some way towards closing #7981 and closing a feature gap with pyright, though not the whole way, as #7981 also asks for additional type narrowing for a finalTypedDict.Test Plan
testCannotUseFinalDecoratorWithTypedDictwas removed, andtestCannotSubclassFinalTypedDictadded.