[BUG] from foo import * imports should be ignored in stub files

[AlexWaygood]

Hi!

I see pycln recently added support for .pyi files. That's awesome!

I'm interested in possibly using pycln in typeshed's CI. However, it seems like there's one part of PEP 484 that pycln isn't quite compliant with when it comes to stub files, namely this:

[...] all objects imported into a stub using from ... import * are considered exported. (This makes it easier to re-export all objects from a given module that may vary by Python version.)

If I run pycln on typeshed at the moment, it erroneously deletes a large number of "unused" from foo import * imports. These imports are all deliberate -- if a type checker sees a from foo import * import in a stub file bar.pyi, it understands all symbols from module foo to be re-exported in module bar.

Playing around with pycln, it looks like this one-line patch solves the problem:

diff --git a/pycln/utils/refactor.py b/pycln/utils/refactor.py
index 4739e72..a241fc8 100644
--- a/pycln/utils/refactor.py
+++ b/pycln/utils/refactor.py
@@ -279,7 +279,7 @@ class Refactor:

                 # Expand any import '*' before checking.
                 node, is_star = self._expand_import_star(node)
-                if is_star is None:
+                if is_star is None or (is_star and self._path.is_stub):
                     continue

                 # Get set of used names.

I'd file a PR, but I'm struggling a little bit with the test suite 😅 (I'm not too familiar with the advanced features of pytest, I'm afraid.)

[hadialqattan]

Hi @AlexWaygood, this is a good catch.. actually, I planned to implement this within PR #150 but forgot to do so.

[hadialqattan]

@AlexWaygood after doing some investigation, your patch looks good to me, so please open a PR, and I'll help you finalize it even if you are unsure where/how to write the unit tests.

[hadialqattan]

+ @AlexWaygood I'm really happy to see you supporting the project. Thanks a lot bro!

[AlexWaygood]

• @AlexWaygood I'm delighted to see you supporting the project. Thanks a lot bro!

Thank you for the very cool tool!

[hadialqattan]

@AlexWaygood I've just published a new release including the fix for this bug: v2.0.2.

[AlexWaygood]

@AlexWaygood I've just published a new release including the fix for this bug: v2.0.2.

Awesome, thanks so much for your help!