CODEWITHSUNDEEP
pythonpython-typing
Dan Halbert
Dan Halbert

Reputation: 2925

Cannot import .pyi file in stubs package

I am trying to build a package of .pyi stub files, for use with type annotations. I have this structure:

m/
  __init__.pyi
  sub.pyi

This works:

>>> import m

This does not (including in Python 3.10):

>>> import m.sub
ModuleNotFoundError: No module named 'm.sub'

If I rename sub.pyi to sub.py, then I can import m.sub. What am I misunderstanding about where I can use .pyi files, or whether I can make multi-file stubs package?

Upvotes: 6

Views: 7288

Answers (1)

Lenormju
Lenormju

Reputation: 4378

cf PEP 484 -- Type Hints :

While stub files are syntactically valid Python modules, they use the .pyi extension to make it possible to maintain stub files in the same directory as the corresponding real module. This also reinforces the notion that no runtime behavior should be expected of stub files.

The .pyi files are not meant to be used by the Python interpreter itself but by type-checking tools.
By default, a Python loader will not look for .pyi files, so you can't import them. But you can import a package (a directory whose name matches what you are importing). That's the reason of your error.

Looking at the stubs files that PyCharm includes, the only imports it does is to actual .py files, never to .pyi files.

Upvotes: 5

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