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benmoran56 / esper

An ECS (Entity Component System) for Python
MIT License
537 stars 67 forks source link

`py.typed` file is missing. #64

Closed HexDecimal closed 2 years ago

HexDecimal commented 2 years ago

This file is needed for PEP 561 to mark the package as type-hinted. Without it the package isn't considered typed when installed as a package or from PyPI.

benmoran56 commented 2 years ago

Thanks for opening the ticket. Unfortunately it doesn't seem like it's currently possible for module-only libraries:

This PEP does not support distributing typing information as part of module-only distributions. The code should be refactored into a package-based distribution and indicate that the package supports typing as described above.

That's unfortunate, but I would prefer not to make esper into a package. Being a single-file library is something I really like about it. One of my goals was to allow users to just copy it into their project without necessarily needing to install it. Any ideas?

HexDecimal commented 2 years ago

A single package without dependencies isn't much more complex than a single module. You would copy an esper directory instead of a esper.py file and you'd import it the exact same way.

benmoran56 commented 2 years ago

esper actually was a package in the past, but was consolidated back to a single module due to some user demand.

If you wouldn't mind, could you explain what you mean by it "isn't considered typed" when installing from PyPi? Running mypy against the module seems to work fine without it. I had a look through the PEP, but couldn't really grasp it all. I guess my question is: what is this breaking by not existing?

Thanks in advance!

HexDecimal commented 2 years ago

When it's vendored then its fine, but when it's installed to site-packages then Mypy won't follow the import of it to look at its types, and you have to tell Mypy to ignore the import to continue.

Mypy will assume that local files are typed, but it needs stub-files or py.typed for an external package.

benmoran56 commented 2 years ago

Thanks for the explaination. And also, thanks for the pull request. I can't say I'm happy about having to change it just for mypy, but I guess it can't be helped at the moment.