Don't issue no-redef with conditional imports #13914

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1. bersbersbers

   added

   bugmypy got something wrongmypy got something wrong

   on Oct 17, 2022
2. bersbersbers commented on Oct 17, 2022

   

   bersbersbers

   on Oct 17, 2022 · Hidden as outdated

   Last edited by bersbersbers

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3. bersbersbers commented on Oct 17, 2022

   

   bersbersbers

   on Oct 17, 2022

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   A workaround can be found in mkorpela/overrides#109 (comment).
4. hauntsaninja

   closed this as completedin #13969on Nov 3, 2022
5. hauntsaninja

   added a commit that references this issue on Nov 3, 2022

   Better story for import redefinitions (#13969)

   ...

   This issue will close once commit a4da89e is merged into the 'master' branch.

   a4da89e
6. bersbersbers commented on Nov 3, 2022

   

   bersbersbers

   on Nov 3, 2022

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   @hauntsaninja I may be missing something, but the code example I posted in #13914 (comment) still issues the same mypy error:

   C:\Code\project>mypy --version
   mypy 1.0.0+dev.a4da89e0543ee0d213b30216c9e15a5d00fcd578 (compiled: no)
   
   C:\Code\project>mypy --no-incremental project\project.py
   project\project.py:6: error: Name "overrides" already defined (possibly by an import)  [no-redef]
   Found 1 error in 1 file (checked 1 source file)
   

   Using overrides==7.3.1
7. hauntsaninja

   reopened this on Nov 3, 2022
8. bersbersbers commented on Feb 7, 2023

   

   bersbersbers

   on Feb 7, 2023

   Last edited by bersbersbers

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   Just for the record (because I had been hoping it might have been fixed), this is still an issue on 1.0.0.
9. bersbersbers commented on Feb 12, 2023

   

   bersbersbers

   on Feb 12, 2023

   Last edited by bersbersbers

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   Some more details:

   """With `overrides==7.3.1` installed, mypy issues `no-redef` in `except`."""
   from typing import Callable, TypeVar
   
   F = TypeVar("F", bound=Callable)
   try:
       from overrides import override
   except ModuleNotFoundError:
       def override(method: F) -> F:
           return method
   
   print(override)

   The workaround works , but stops working when removing overrides:

   """The workaround silences `mypy`, but now mypy issues `no-redef` in *`try`* if `overrides` is *not* installed."""
   from typing import Callable, TypeVar
   
   F = TypeVar("F", bound=Callable)
   
   # Workaround
   override: Callable[[F], F]
   try:
       from overrides import override
   except ModuleNotFoundError:
       def override(method: F) -> F:
           return method
   
   print(override)

   This is a problem if one uses a construct such as this to import typing.override (from Python 3.12 on):

   """Prepare for Python 3.12."""
   from typing import Callable, TypeVar
   
   F = TypeVar("F", bound=Callable)
   
   # Workaround
   override: Callable[[F], F]
   try:
       from typing import override
   except ModuleNotFoundError:
       def override(method: F) -> F:
           return method
   
   print(override)

   For the record, this works:

   """Prepare for Python 3.12."""
   import sys
   from typing import Callable, TypeVar
   
   F = TypeVar("F", bound=Callable)
   
   if sys.version_info >= (3, 12):
       from typing import override
   else:
       def override(method: F) -> F:
           return method
   
   print(override)
10. marmarek

    added a commit that references this issue on Jan 1, 2025

    Workaround mypy false no-redef message

    ...

    a50dd7f