I can't trigger the classic "partially initialized module" ImportError anymore in 3.13

sausix · June 29, 2025, 9:15am

So I’m supposed to discuss CPython issues/changes here for some reason.

Here’s my bugreport which was closed without reading:

github.com/python/cpython

Getting ImportError and suggestion to rename module for no valid reason

opened 09:03AM - 29 Jun 25 UTC

closed 09:04AM - 29 Jun 25 UTC

sausix

type-bug

# Bug report ### Bug description: I can't trigger the classic "partially initi…alized module" ImportError anymore. Circular imports are a different issue and not related to shadowing one of `sys.stdlib_module_names` for example. ```python # mainmod.py from secondmod import secondaryitem mainitem = 1 ``` ```python # 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: ```pytb # 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: ```pytb 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

tjreedy · June 30, 2025, 3:02am

The issue was thought to be about user code. With this cleared up, the issue has been reopened, so comment there.