Description

sausix

opened on Jun 29, 2025

Issue body actions

Bug report

Bug description:

I can't trigger the classic "partially initialized module" ImportError anymore.
Circular imports are a different issue and not related to shadowing one of sys.stdlib_module_names for example.

# mainmod.py
from secondmod import secondaryitem

mainitem = 1

# secondmod.py
from mainmod import mainitem

secondaryitem = 2

I made sure there is no package installed providing mainmod or secondmod.

In Python 3.13.5:

# python3 mainmod.py

Traceback (most recent call last):
  File "/home/as/mainmod.py", line 1, in <module>
    from secondmod import secondaryitem
  File "/home/as/secondmod.py", line 1, in <module>
    from mainmod import mainitem
  File "/home/as/mainmod.py", line 1, in <module>
    from secondmod import secondaryitem
ImportError: cannot import name 'secondaryitem' from 'secondmod' (consider renaming '/home/as/secondmod.py' if it has the same name as a library you intended to import)

Before in Python 3.12.6:

python3 mainmod.py

Traceback (most recent call last):
  File "/home/as/mainmod.py", line 1, in <module>
    from secondmod import secondaryitem
  File "/home/as/secondmod.py", line 1, in <module>
    from mainmod import mainitem
  File "/home/as/mainmod.py", line 1, in <module>
    from secondmod import secondaryitem
ImportError: cannot import name 'secondaryitem' from partially initialized module 'secondmod' (most likely due to a circular import) (/home/as/secondmod.py)

Because it's an improvement mostly for beginners, the warning should appear only when colliding with sys.stdlib_module_names or maybe other installed third party packages. It should not trigger for modules of the same project.

I've read the threads about this new Python 3.13 feature and could not find any report on this false positive warning.

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Activity

1. sausix

   added

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Jun 29, 2025
2. hugovk commented on Jun 29, 2025

   

   hugovk

   on Jun 29, 2025

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   Hello, this is the issue tracker for the Python language itself.

   Please open a topic in the help forum to ask about your own code:

   https://discuss.python.org/c/help/7
3. hugovk

   closed this as not plannedon Jun 29, 2025
4. sausix commented on Jun 29, 2025

   

   sausix

   on Jun 29, 2025

   Author

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   I know the difference between Python and CPython.

   And it's an issue/change in CPython. It's not about my own code.

   Reacted by BrenBarn
5. hugovk commented on Jun 29, 2025

   

   hugovk

   on Jun 29, 2025

   Member

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   One of these changes was from #112577, cc @hauntsaninja.
6. hugovk

   reopened this on Jun 29, 2025
7. StanFromIreland

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   on Jun 29, 2025
8. brianschubert commented on Jun 29, 2025

   

   brianschubert

   on Jun 29, 2025

   Contributor

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   For reference, the "consider renaming" error was introduced by #113769
9. hauntsaninja commented on Jun 29, 2025

   

   hauntsaninja

   on Jun 29, 2025

   Contributor

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   Thanks for the issue!

   There are actually two separate warnings we issue, one for the standard library case and one for the potential third party case:

   • The standard library one checks against sys.stdlib_module_names as you suggest, and the error message is something like: AttributeError: module 'random' has no attribute 'randint' (consider renaming '/home/me/random.py' since it has the same name as the standard library module named 'random' and prevents importing that standard library module)

   • The potential third party case message is something like: AttributeError: module 'numpy' has no attribute 'array' (consider renaming '/home/me/numpy.py' if it has the same name as a library you intended to import)

   Two notes:

   • There are plenty of cases where we preserve the error message for circular imports as they were on Python 3.12 , see here
   • The message used to say "if it has the same name as a third-party module" instead of "library", but Pablo asked for the change in: gh-123930: Better error for "from imports" when script shadows module #123929 (comment)

   Here are the things I'm solving for:

   • I would like to issue some "consider renaming" message in the third party shadowing case
     • In my experience / from forums, it is basically as common for beginners to have numpy.py or requests.py or openai.py as it is for them to have random.py, and PyPI is only becoming more and more useful
   • I don't think it is tenable to scan site.getsitepackages (or try to use importlib.metadata.distributions or similar). This can be really slow. Also recursive imports while handling import errors can lead to some really cursed situations that can cause the interpreter to crash

   Are there tweaks that would have made you less confused? For instance:

   • We can restore the error message to lead with "partially initialized module" instead of "module"
   • We can lead with the "if" clause, i.e. "If ... has the same name as a library you intended to import, consider renaming ..." instead of "Consider renaming ... if ...."
10. hauntsaninja commented on Apr 10, 2026

    

    hauntsaninja

    on Apr 10, 2026

    Contributor

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    Closing, since OP never reacted to my suggestions, and we haven't seen additional cases of confusion
11. hauntsaninja

    closed this as not plannedon Apr 10, 2026
12. sausix commented on Apr 10, 2026

    

    sausix

    on Apr 10, 2026

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    I reported a bug. Clearly a regression.
    Then this issue has been automatically closed for reason "Everybody is unaware between the difference of Python and CPython".
    I had to register on another site to open a discussion for reopening this issue.

    Now this issue is on me? I've done enough so far. It's not my job to find a solution for you on a simple issue.

    Yeah just close it if you prefer better statistics than solving issues.

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