Inconsistent module resolution when running Python file directly vs. importing it (ModuleNotFoundError differences)

[SahilKumarSingh01]

Bug report

Bug description:

Bug Report: Inconsistent Import Error Between Direct Execution and Module Import

Description

A Python script containing the line:

from six.moves import configparser

produces two different ModuleNotFoundError messages depending on how it is executed.

• When run directly:
  ModuleNotFoundError: No module named 'six'

• When imported via another script:
  ModuleNotFoundError: No module named 'six.moves'

Both scenarios use the exact same code, so this suggests inconsistent behavior in how Python handles imports in __main__ versus module import mode.

Steps to Reproduce

1. Create a file named test_import.py:

from six.moves import configparser

2. Run it directly:

python test_import.py

3. Create another file named runner.py:

import test_import

4. Run:

python runner.py

5. Compare the error messages from both executions.

Expected Behavior

Python should produce consistent import error messages regardless of whether a module is run directly or imported.

Actual Behavior

Running directly reports:

ModuleNotFoundError: No module named 'six'

Importing through another script reports:

ModuleNotFoundError: No module named 'six.moves'

Environment

• Python version: (fill in)
• OS: Windows 10/11
• Installation method: (official installer / store / embeddable zip / etc.)
• No virtual environment active

Additional Notes

This issue appeared while debugging the gsutil tool bundled with another project.
Even after reinstalling all libraries, the inconsistent import error persists.

CPython versions tested on:

3.14

Operating systems tested on:

Windows

[serhiy-storchaka]

I cannot reproduce. But I get No module named 'six.moves' if there is a directory named six. Perhaps there is a directory named six in the import path in your latter example?

Please don't use screenshots. They are hard to read and text cannot be copied from them.

[SahilKumarSingh01]

actually i was trying to build cef for windows x64 using cmake of latest version and python 3.14 it was producing that error but when i downgrade my python to 3.9 it worked fine i am wondering why a latestest version shows module import error i tried to uninstall six package then in first code i try to load it directly from script in second run cmake . I notice difference in module not found error in both case. I thought it would be helpful to figure out what is causing this error

[johnslavik]

@SahilKumarSingh01, thanks for the report!
There isn’t enough information right now to reproduce the issue.
If more details come up that confirm the bug, the issue can definitely be revisited :)
(CC @ZeroIntensity (mentorship), label: invalid)

[picnixz]

I think there were directory leftovers, likely a six package in one of your two examples. I don't know how you tried to "downgrade" your Python and which exact commands you executed, but we need a clear reproducer. I suggest that you:

• always use the same Python version for comparing the error tracebacks
• use a clean directory and ensure that the python library being used is correctly setup (either through a virtual environment or via a container). As Serhiy said, one reason could simply because six existed in one of your examples (and the error message is then expected because in one case it was possible to find six but not six/moves.py or six/moves while in the other case six did not even exist.

I'm going to close this one until a proper reproducer is given.