Description

krfricke

opened on Jan 21, 2023

Issue body actions

Bug report

Global packages (e.g. enum) try to import from local packages in the current working dir, even if a same-named stdlib package exists.

For instance, if a types.py exists in the local directory, import enum will fail:

> touch types.py
> python
Python 3.10.9 (main, Jan 20 2023, 17:02:49) [Clang 13.0.0 (clang-1300.0.27.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import enum
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/kai/.pyenv/versions/3.10.9/lib/python3.10/enum.py", line 2, in <module>
    from types import MappingProxyType, DynamicClassAttribute
ImportError: cannot import name 'MappingProxyType' from 'types' (/home/kai/sandbox/types.py)

The correct package to import should be the stdlib types.py package, not the local types.py.

Your environment

• CPython versions tested on: Python 3.10.4, 3.10.9, 3.8.6
• Bug does not come up in 3.8.7
• Operating system and architecture: Mac x86_64

Activity

1. krfricke

   added

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

   on Jan 21, 2023
2. hauntsaninja commented on Jan 21, 2023

   

   hauntsaninja

   on Jan 21, 2023

   Contributor

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   Duplicate of #95893, #90482, #42852, #73790, #66368, #65577, #65401, etc

   See https://ncoghlan-devs-python-notes.readthedocs.io/en/latest/python_concepts/import_traps.html#the-name-shadowing-trap
3. hauntsaninja

   closed this as not plannedon Jan 21, 2023
4. eryksun commented on Jan 21, 2023

   

   eryksun

   on Jan 21, 2023

   Contributor

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   When running interactively, an empty string is prepended to sys.path. This gets evaluated to whatever the current working directory is at the time of each import. When running a script, the directory of the script gets prepended to sys.path. Usually the script directory is not the same as the current working directory.

   You can run in isolated mode (i.e. -I command-line option) to avoid prepending either the working directory or the script directory. However, this is an extreme measure that also disables reading PYTHON* environment variables and the user site packages. Starting with Python 3.11, there's a -P command-line option to get a safe sys.path that doesn't prepend these directories.
5. krfricke commented on Jan 21, 2023

   

   krfricke

   on Jan 21, 2023

   Author

   More actions

   Thanks for the explanation and sorry for the duplicate (I tried searching but didn't find the other issues).

   Looking forward to the -P option - for our case we found another workaround.

   Thanks!
6. krfricke

   added a commit that references this issue on Jan 24, 2023

   Fix setup-dev.py stdlib import shadowing (#31829)

   3e1cdeb
7. picnixz

   marked shadowing error with traceback module leads to unexpected code execution #138170 as a duplicate of this issue on Aug 28, 2025

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