Saving any python file clears user-generated files in the pytest cache

[vberlier]

Type: Bug

Behaviour

Expected vs. Actual

I'm using a pytest fixture to download and cache some file with the pytest.Cache api. In the minimal reproduction below the file is saved in .pytest_cache/d/demo/the_file.txt. However I noticed that the file gets re-downloaded way more often than expected. It turns out vscode is deleting the .pytest_cache/d/demo directory any time a python file is saved in the workspace.

Steps to reproduce:

Install pytest in a new virtualenv and create test_demo.py:

from pathlib import Path

import pytest

@pytest.fixture
def the_file(cache: pytest.Cache) -> Path:
    directory = cache.mkdir("demo")
    the_file = directory / "the_file.txt"

    if not the_file.is_file():
        print("create the file!")
        the_file.write_text("hello\n")

    return the_file

def test_foo(the_file: Path):
    assert the_file.read_text() == "not hello\n"

Run pytest once. Notice that the output shows create the file!.

Open the explorer you should see that .pytest_cache/d/demo/the_file.txt was created.

Run pytest again. Notice that as expected the test no longer outputs create the file!.

Now make a dummy modification to save the file test_demo.py.

Immediately after saving the .pytest_cache/d/demo directory disappears.

The log also shows that vscode is running a command to discover tests, with a suspicious --cache-clear argument:

[info] > ./.venv/bin/python ~/.vscode-server/extensions/ms-python.python-2023.8.0/pythonFiles/testing_tools/run_adapter.py discover pytest -- --rootdir . -s --cache-clear
[info] cwd: .

If you try running pytest again you'll notice that the output shows create the file!.

Diagnostic data

• Python version (& distribution if applicable, e.g. Anaconda): 3.10.6
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Pylance

User Settings

languageServer: "Pylance"

linting
• enabled: false

formatting
• provider: "black"

testing
• pytestEnabled: true

Extension version: 2023.8.0
VS Code version: Code 1.78.0 (252e5463d60e63238250799aef7375787f68b4ee, 2023-05-03T20:09:00.748Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Sandboxed: No
Connection to 'wsl+Ubuntu' could not be established
Remote OS version: Linux x64 5.15.90.1-microsoft-standard-WSL2

[eleanorjboyd]

Sorry I haven't said much more on this issue but I do realize this is a bug and will be fixing it. Thanks

[eleanorjboyd]

We have gotten rid of all the arg editing with the rewrite so this should be fixed! Please comment if you are not seeing the fix on the rewrite and I can investigate. Thanks!