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Question: assigning the same type to all entries in a module #18813
Description
Is it possible to let mypy infer programmatically that all members of a given module have the same type? We run into this problem in astropy for definitions of units; in our code, prefixed versions are generated automatically, so it is less obvious how to infer the type, and the fall-back we are considering is automatically generated stub files. But I wonder if one cannot be smarter. E.g., I think if the units were in a dict[str, Unit], it would work, but is there a way to let mypy know that everything in a given module has type Unit by default?
Context: astropy/astropy#17902 - I'd prefer to avoid to add ~100KiB of stub files!
Activity
A5rocks commentedon Mar 18, 2025
Does module-level
__getattr__work for you?mhvk commentedon Mar 19, 2025
Interesting, I hadn't really thought about how not defining the units but creating them on demand with
__getattr__which is clearly annotated to produce only units might do the trick. It might actually be handy overall in our implementation (see astropy/astropy#17902 (comment)). But I partially wrote this issue because I'm not super familiar with typing yet am reviewing a PR that would add ~100KiB worth of stubs, and am trying to think of ways to avoid that -- so I'm asking our more typing-versed people over at that issue.hauntsaninja commentedon Mar 19, 2025
You can lie in the stub and have a
__getattr__in the.pyifile even if that's not the strategy you take to creating attributes at runtime in the.pyfile