Fix crash with malformed TypedDicts and disllow-any-expr#13963
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JukkaL merged 1 commit intopython:masterfrom Oct 31, 2022
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Fix crash with malformed TypedDicts and disllow-any-expr#13963JukkaL merged 1 commit intopython:masterfrom
JukkaL merged 1 commit intopython:masterfrom
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Fixes python#13066 During the semanal phase, mypy opts to ignore and skip processing any malformed or illegal statements inside of a TypedDict class definition, such as method definitions. Skipping semanal analysis on these statements can cause any number of odd downstream problems: the type-checking phase assumes that all semanal-only semantic constructs (e.g. FakeInfo) have been purged by this point, and so can crash at any point once this precondition has been violated. This diff opts to solve this problem by filtering down the list of statements so we keep only the ones we know are legal within a TypedDict definition. The other possible solution to this problem is to modify mypy so we skip checking TypedDict class bodies entirely during type checking and fine-grained deps analysis. Doing this would also let address python#10007 and supersede my other diff python#13732. I decided against doing this for now because: 1. I wasn't sure if this was actually safe, especially in the fine-grained deps phase and for mypyc. 2. I think no matter what, the semanal phase should not leak semanal-only types: relaxing this postcondition would make it harder to reason about mypy. So, we'd probably want to make this change regardless of what we do in the later phases.
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According to mypy_primer, this change has no effect on the checked open source code. 🤖🎉 |
JukkaL
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Oct 31, 2022
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Great, I agree that this makes it much easier to reason about what will happen in later phases of type checking.
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Fixes #13066
During the semanal phase, mypy opts to ignore and skip processing any malformed or illegal statements inside of a TypedDict class definition, such as method definitions.
Skipping semanal analysis on these statements can cause any number of odd downstream problems: the type-checking phase assumes that all semanal-only semantic constructs (e.g. FakeInfo) have been purged by this point, and so can crash at any point once this precondition has been violated.
This diff opts to solve this problem by filtering down the list of statements so we keep only the ones we know are legal within a TypedDict definition.
The other possible solution to this problem is to modify mypy so we skip checking TypedDict class bodies entirely during type checking and fine-grained deps analysis. Doing this would also let address #10007 and supersede my other diff #13732.
I decided against doing this for now because: