Test Discovery hangs in WSL

[PaleNeutron]

Type: Bug

Behaviour

Testing panel is always empty and log shows

2025-02-05 14:02:42.284 [debug] Testing: Refreshing all test data
2025-02-05 14:02:42.287 [info] Discover tests for workspace name: sqlmodel - uri: /home/john/contribute/sqlmodel
2025-02-05 14:02:42.293 [debug] Starting Test Discovery named pipe

Steps to reproduce:

git clone https://github.com/dexplo/dataframe_image
cd dataframe_image
python -m venv .venv
source .venv/bin/activate
pip install pytest pytest-asyncio
pip install -e .
code .

Then open testing panel

Diagnostic data

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

2025-02-07 09:12:30.822 [info] Experiment 'pythonRecommendTensorboardExt' is active
2025-02-07 09:12:30.822 [info] Experiment 'pythonTerminalEnvVarActivation' is active
2025-02-07 09:12:30.822 [info] Experiment 'pythonTestAdapter' is active
2025-02-07 09:12:30.822 [info] Native locator: Refresh started
2025-02-07 09:12:30.822 [info] Native locator: Refresh started
2025-02-07 09:12:30.822 [info] Native locator: Refresh started
2025-02-07 09:12:31.924 [info] Pyenv environment manager found at: /home/john/.pyenv/bin/pyenv
2025-02-07 09:12:32.158 [info] Poetry environment manager found at: /home/john/.local/pipx/venvs/poetry/bin/poetry
2025-02-07 09:12:32.388 [info] Native locator: Refresh finished in 8887 ms
2025-02-07 09:12:32.391 [info] > D:\Program Files\Python312\python.exe -c "import sys;print(sys.executable)"
2025-02-07 09:12:32.393 [info] > ~/.pyenv/bin/pyenv which python
2025-02-07 09:12:32.393 [info] cwd: .
2025-02-07 09:12:32.470 [error] Error: Command failed: D:\Program Files\Python312\python.exe -c "import sys;print(sys.executable)"
/bin/sh: 1: D:Program: not found

    at genericNodeError (node:internal/errors:984:15)
    at wrappedFn (node:internal/errors:538:14)
    at ChildProcess.exithandler (node:child_process:422:12)
    at ChildProcess.emit (node:events:530:35)
    at maybeClose (node:internal/child_process:1104:16)
    at Socket.<anonymous> (node:internal/child_process:456:11)
    at Socket.emit (node:events:518:28)
    at Pipe.<anonymous> (node:net:343:12) {
  code: 127,
  killed: false,
  signal: null,
  cmd: 'D:\\Program Files\\Python312\\python.exe -c "import sys;print(sys.executable)"'
}
2025-02-07 09:12:35.355 [info] Starting Pylance language server.
2025-02-07 09:12:57.726 [info] > conda info --json
2025-02-07 09:12:57.850 [info] Native locator: Refresh started
2025-02-07 09:12:57.866 [info] Pyenv environment manager found at: /home/john/.pyenv/bin/pyenv
2025-02-07 09:12:57.867 [info] Poetry environment manager found at: /home/john/.local/pipx/venvs/poetry/bin/poetry
2025-02-07 09:13:00.037 [info] Native locator: Refresh finished in 2185 ms
2025-02-07 09:13:01.569 [info] Discover tests for workspace name: dataframe_image - uri: /home/john/projects/misc/dataframe_image
2025-02-07 09:13:01.569 [info] Python interpreter path: ./.venv/bin/python
2025-02-07 09:13:01.693 [info] > . ./.venv/bin/activate && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode-server/extensions/ms-python.python-2025.1.2025020602-linux-x64/python_files/printEnvVariables.py
2025-02-07 09:13:01.693 [info] shell: zsh
2025-02-07 09:13:01.799 [info] > ~/.pyenv/versions/3.8.19/bin/python ~/.vscode-server/extensions/ms-python.python-2025.1.2025020602-linux-x64/python_files/printEnvVariables.py
2025-02-07 09:13:01.800 [info] shell: zsh
2025-02-07 09:13:04.332 [info] Prepending environment variable PATH in collection with /home/john/.vscode-server/extensions/ms-python.python-2025.1.2025020602-linux-x64/python_files/deactivate/zsh:/home/john/projects/misc/dataframe_image/.venv/bin: {"applyAtShellIntegration":true,"applyAtProcessCreation":true}
2025-02-07 09:13:04.332 [info] Setting environment variable VIRTUAL_ENV in collection to /home/john/projects/misc/dataframe_image/.venv {"applyAtShellIntegration":true,"applyAtProcessCreation":true}
2025-02-07 09:13:04.332 [info] Prepending environment variable PS1 in collection with (.venv)  {"applyAtShellIntegration":true,"applyAtProcessCreation":false}
2025-02-07 09:13:04.332 [info] Setting environment variable VIRTUAL_ENV_PROMPT in collection to (.venv)  {"applyAtShellIntegration":true,"applyAtProcessCreation":true}
2025-02-07 09:13:04.333 [info] Send text to terminal: /usr/bin/python3.8 /home/john/.vscode-server/extensions/ms-python.python-2025.1.2025020602-linux-x64/python_files/printEnvVariablesToFile.py /home/john/.vscode-server/extensions/ms-python.python-2025.1.2025020602-linux-x64/python_files/deactivate/zsh/envVars.txt
2025-02-07 09:14:49.103 [info] Discover tests for workspace name: undefined - uri: c:/Users/049171/AppData/Roaming/Code/User/settings.json
2025-02-07 09:14:49.103 [error] Unable to find workspace for given file
2025-02-07 09:15:02.436 [info] Discover tests for workspace name: dataframe_image - uri: /home/john/projects/misc/dataframe_image
2025-02-07 09:15:02.436 [error] Test discovery already in progress, not starting a new one.

Extension version: 2025.0.0
VS Code version: Code 1.96.4 (cd4ee3b1c348a13bafd8f9ad8060705f6d4b9cba, 2025-01-16T00:16:19.038Z)
OS version: Windows_NT x64 10.0.19043
Modes:
Remote OS version: Linux x64 5.15.153.1-microsoft-standard-WSL2
Remote OS version: Linux x64 5.15.153.1-microsoft-standard-WSL2
Remote OS version: Linux x64 5.15.153.1-microsoft-standard-WSL2

• Python version (& distribution if applicable, e.g. Anaconda): 3.12.3
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Pylance

User Settings

languageServer: "Pylance"

testing
• pytestArgs: "<placeholder>"
• pytestEnabled: true

Installed Extensions

Extension Name	Extension Id	Version
cmake	twx	0.0.17
cmake-tools	ms-	1.19.52
color-highlight	nau	2.8.0
copilot	Git	1.265.0
copilot-chat	Git	0.23.2
copy-json-path	Mal	1.4.0
cpptools	ms-	1.23.5
csharp	ms-	2.63.32
datawrangler	ms-	1.18.0
debugpy	ms-	2025.0.0
docs-yaml	doc	1.0.5
even-better-toml	tam	0.21.2
gc-excelviewer	Gra	4.2.62
gitignore	cod	0.9.0
gitlens	eam	16.2.2
go	gol	0.44.0
hexeditor	ms-	1.11.1
intellicode-api-usage-examples	Vis	0.2.9
java	red	1.39.0
js-debug	ms-	1.96.0
jupyter	ms-	2024.11.0
jupyter-renderers	ms-	1.1.0
latex-workshop	Jam	10.7.5
linter-gfortran	for	3.2.0
markdown-all-in-one	yzh	3.6.2
mdmath	goe	2.7.4
myst-highlight	Exe	0.11.0
native-ascii-converter	cwa	1.0.9
plantuml	jeb	2.18.1
prettier-vscode	esb	11.0.0
psi-header	psi	1.25.0
python	ms-	2025.1.2025020602
rainbow-csv	mec	3.16.0
react-component-generator	And	1.1.1
rest-client	hum	0.25.1
ruff	cha	2025.6.0
shell-format	fox	7.2.5
simple-react-snippets	bur	1.2.8
volar	Vue	2.2.0
vscode-django	bat	1.15.0
vscode-docker	ms-	1.29.4
vscode-dotnet-runtime	ms-	2.2.6
vscode-eslint	dba	3.0.10
vscode-fileheader	mik	0.0.2
vscode-gradle	vsc	3.16.4
vscode-graphql	Gra	0.13.0
vscode-java-debug	vsc	0.58.1
vscode-java-dependency	vsc	0.24.1
vscode-java-pack	vsc	0.29.0
vscode-js-profile-table	ms-	1.0.10
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
vscode-kubernetes-tools	ms-	1.3.20
vscode-markdownlint	Dav	0.58.2
vscode-maven	vsc	0.44.0
vscode-pull-request-github	Git	0.102.0
vscode-pylance	ms-	2025.2.1
vscode-sql-beautify	cla	0.3.23
vscode-sql-formatter	adp	1.4.4
vscode-xml	red	0.27.2
vscode-yaml	red	1.15.0
vscodeintellicode	Vis	1.3.2
xml	Dot	2.5.1

System Info

Item	Value
CPUs	11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz (16 x 2496)
GPU Status	2d_canvas: enabled canvas_oop_rasterization: enabled_on direct_rendering_display_compositor: disabled_off_ok gpu_compositing: enabled multiple_raster_threads: enabled_on opengl: enabled_on rasterization: enabled raw_draw: disabled_off_ok skia_graphite: disabled_off video_decode: enabled video_encode: enabled vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	undefined
Memory (System)	31.69GB (6.24GB free)
Process Argv	--folder-uri=vscode-remote://wsl+Ubuntu/home/john/projects/cell-strategy-backend --remote=wsl+Ubuntu --crash-reporter-id e0824f99-80f6-4908-9ff9-e2859bce8a44
Screen Reader	no
VM	0%

Item	Value
Remote	WSL: Ubuntu
OS	Linux x64 5.15.153.1-microsoft-standard-WSL2
CPUs	11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz (16 x 0)
Memory (System)	11.68GB (3.87GB free)
VM	0%

Item	Value
Remote	WSL: Ubuntu
OS	Linux x64 5.15.153.1-microsoft-standard-WSL2
CPUs	11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz (16 x 0)
Memory (System)	11.68GB (3.87GB free)
VM	0%

Item	Value
Remote	WSL: Ubuntu
OS	Linux x64 5.15.153.1-microsoft-standard-WSL2
CPUs	11th Gen Intel(R) Core(TM) i7-11700 @ 2.50GHz (16 x 0)
Memory (System)	11.68GB (3.87GB free)
VM	0%

A/B Experiments

vsliv368cf:30146710
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscod805:30301674
binariesv615:30325510
vsaa593cf:30376535
py29gd2263:31024239
c4g48928:30535728
azure-dev_surveyone:30548225
a9j8j154:30646983
962ge761:30959799
pythonmypyd1:30879173
h48ei257:31000450
pythontbext0:30879054
cppperfnew:31000557
dwnewjupyter:31046869
nativerepl2:31139839
pythonrstrctxt:31112756
nativeloc1:31192215
iacca1:31171482
5fd0e150:31155592
dwcopilot:31170013
stablechunks:31184530
6074i472:31201624
dwoutputscf:31232845
9064b325:31222308
copilot_t_ci:31222730

[eleanorjboyd]

thanks for the repro steps will take a look

[qodfathr]

Seeing the same

2025-02-08 19:03:23.969 [info] ============================= test session starts ==============================
platform linux -- Python 3.11.10, pytest-8.3.4, pluggy-1.5.0
rootdir: /home/myname/repos/myrepo
configfile: pyproject.toml
plugins: jaxtyping-0.2.37, cov-6.0.0, typeguard-4.4.1, anyio-4.2.0, hydra-core-1.3.2, mock-3.14.0

(Hung at this point.)

If I copy the pytest --collect-only command being executed and run it in my shell, it does not hang and completes successfully.

[CagriYonca]

I was facing the same issue, I executed pytest --collect-only and the result was also identical. Stash your changes and try again. I guess some broken code causes Pytest to get into the infinite loop.

[PaleNeutron]

I was facing the same issue, I executed pytest --collect-only and the result was also identical. Stash your changes and try again. I guess some broken code causes Pytest to get into the infinite loop.

No, I clone exactly same repo to both WSL and Windows, without not modifying any code, workspace in WSL hangs but in Windows works.

[danbartl]

Same for me, this is a blocking issue on WSL2 that is definitely not releated to any failed tests.

[eleanorjboyd]

Hi! If you downgrade the python extension does this then work? Also what if you try it without any pytest plugins? I do not have a good way to repro on a WSL setup so sorry for having to ask yall to try things out. Thanks!

[danbartl]

Yes downgrading works

[eleanorjboyd]

can you send me your logs when downgraded? I am curious if the issue might be that you weren't on the rewrite experiment which we just made default in 2025.0. When downgrading you can add this to your logs to opt in and see if that breaks it since that helps narrow down where I should look. "python.experiments.optInto": ["pythonTestAdapter"]

[AdrianB-sovo]

I have the same problem (also on WSL2).
When I run pytest --collect-only, everything is collected quickly, but in VSCode, it hangs indefinitely.
I tried both "python.experiments.optInto": ["pythonTestAdapter"] and "python.experiments.optOutFrom": ["pythonTestAdapter"], without success.

My .vscode/settings.json currently contains:

{
    "python.testing.pytestEnabled": true,
    "python.testing.unittestEnabled": false,
    "python.testing.pytestArgs": [
        "--no-cov",
        "./test"
    ],
    // ...
}

P.S. - I also tried the pre-release version of the Python extension and still no success.

[AdrianB-sovo]

I found the problem: in Server output, there was an error like EACCES: permission denied /run/user/1000/<something>.
After executing the following, it works:

1. sudo mkdir /run/user/1000
2. sudo chown -R <user> /run/user/1000
3. Reloading the window and going on the Testing tab.

If it helps, I'm using Ubuntu 22.04.5 LTS on WSL2.

[PaleNeutron]

2. /run/user/1000

Thanks, I found the origin bug and a permanent solution at microsoft/WSL#10496 (comment)