[Muspi Merol (CNSeniorious000)]

Since vscode-python injects PYTHONSTARTUP into pythonrc.py to show the "Ctrl click to launch VS Code Native REPL" message, traceback always shows lines inside pythonrc.py in the interactive console.

Example:

That's because python sets __main__ to the pythonrc.py module, which has a __loader__ attribute. The __loader__ object is then exposed in the global namespace of the interactive console. However, linecache uses __loader__ to get the source code, causing the mismatch.

After this PR, the traceback points to the right source now:

In the _pyrepl.__main__ module, there was some comment mentioning this behavior and they set __loader__ = None to avoid this. See python/cpython#129098 for more information

[Copilot]

Pull request overview

This PR fixes a traceback mismatch issue in the Python interactive console caused by VS Code's pythonrc.py injection. When PYTHONSTARTUP points to pythonrc.py, Python exposes the module's __loader__ in the global namespace, which causes linecache to incorrectly display tracebacks pointing to pythonrc.py instead of the actual source files.

Key Changes:

• Sets __spec__ and __loader__ to None in pythonrc.py to prevent linecache from caching this file
• Adds an explanatory comment documenting why these attributes are set to None

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

The new behavior of setting __spec__ and __loader__ to None should have test coverage to ensure that these attributes are properly set and that they prevent linecache from incorrectly caching this file. Consider adding a test that verifies these attributes are None after module import.

[Eleanor Boyd (eleanorjboyd)]

Hi Muspi Merol (@CNSeniorious000)! Sorry for the delay on getting around to this, two items:

1. can you create an issue and tag it in this PR, that way we can better track the fix through our release process
2. the failing smoke tests should no longer appear after this new run as that was a flaky test we skipped for now

[Eleanor Boyd (eleanorjboyd)]

closing as stale

[Muspi Merol (CNSeniorious000)]

I've added #26234 with an end-to-end repro in VS Code 1.141.2, Python extension 2026.10.0, and Python 3.14.8. The dynamic compile() case still reproduces in the integrated terminal; applying this PR's fix and starting a fresh REPL resolves it. Could you reopen this PR?

[Eduardo Villalpando Mello (edvilme)]

Hello, yes. This should be reopened. Taking a look :)

[Eduardo Villalpando Mello (edvilme)]

Changes look good, and reflect the fix from upstream cpython. Added references to the cpython link and pr that are related to this.
Thanks for the fix :)

[Eduardo Villalpando Mello (edvilme)]

Related python/cpython#137576