After latest update: Testing tree of python tests reloads completely rather than just update

[tepedersen]

Does this issue occur when all extensions are disabled?: Yes/No

• VS Code Version:
• Version: 1.109.5
  Commit: 072586267e68ece9a47aa43f8c108e0dcbf44622
  Date: 2026-02-19T19:43:32.382Z
  Electron: 39.3.0
  ElectronBuildId: 13313481
  Chromium: 142.0.7444.265
  Node.js: 22.21.1
  V8: 14.2.231.22-electron.0
  OS: Linux x64 6.17.0-14-generic
• OS Version: Ubuntu 25.10

Prior to the latest update (I think, I've been coding in the typescript part of my codebase for a couple of weeks and just recently returned to the python part) changing code would discover new tests and update the test-tree in the Testing view in situ, ie adding a new test-method and saving would cause it to appear in the list of tests.

Now, any change (even just adding an empty line in a random, non-test feil, as in the video below) will cause the entire "Python Tests" tree to be removed and then rebuild from scratch, see video below. This causes flicker and delays from saving a file to being able to find the test and re-run it. The vitest part of the tests does not have this issue, leading me to think it an issue specific to python and python test discovery/updating of test list in Testing view

No changes in project setup or extensions prior to this issue appearing. Tried "Python: Clear cache and Reload window" and multiple restarts of VS Code.

Steps to Reproduce:

1. Make any change in any .py file
2. Save file

Output log from Python during a save attached

Python-after-save-file.log

[eleanorjboyd]

thanks will take a look!