Python virtual environment not correctly activated in terminal with uv and WSL

[diego-pm]

Type: Bug

I am developing with python in WSL2, and using uv to create the virtual environment. However, when opening the integrated terminal of vs code, the virtual environment does not get automatically activated correctly.

It seems that it is automatically activated because the name of the environment appears in the prompt, but I cannot access the executables (such as python). Also, the reported python version is the system python version, not the python version of the virtual environment.

on git develop via py v3.12.3 (.venv) 
> python
Command 'python' not found, did you mean:
  command 'python3' from deb python3
  command 'python' from deb python-is-python3

on git develop via py v3.12.3 (.venv) 
>

I need to manually activate the environment running source ./.venv/bin/activate. Then, I can correctly execute python use the libraries in the virtual environment from the terminal.

on git develop via py v3.12.3 (.venv) 
> source ./.venv/bin/activate

on git develop via py v3.10.16 (.venv) 
> python
Python 3.10.16 (main, Feb 12 2025, 14:50:02) [Clang 19.1.6 ] on linux
Type "help", "copyright", "credits" or "license" for more information.
Ctrl click to launch VS Code Native REPL
>>> 

VS Code version: Code 1.98.1 (2fc07b8, 2025-03-10T15:38:08.854Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2

System Info

Item	Value
CPUs	Intel(R) Core(TM) Ultra 7 165U (14 x 2688)
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)	15.46GB (1.75GB free)
Process Argv	--crash-reporter-id 74d13807-d8a0-4836-95d0-b6a8d2261209
Screen Reader	no
VM	0%

Item	Value
Remote	WSL: Ubuntu
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	Intel(R) Core(TM) Ultra 7 165U (14 x 0)
Memory (System)	7.49GB (4.88GB free)
VM	0%

Extensions (36)

Extension	Author (truncated)	Version
markdown-mermaid	bie	1.27.0
ruff	cha	2025.14.0
path-intellisense	chr	2.10.0
copilot	Git	1.282.0
copilot-chat	Git	0.25.0
vscode-pull-request-github	Git	0.106.0
rainbow-csv	mec	3.18.0
git-graph	mhu	1.30.0
debugpy	ms-	2025.4.1
python	ms-	2025.2.0
vscode-pylance	ms-	2025.3.1
datawrangler	ms-	1.20.1
jupyter	ms-	2025.2.0
jupyter-keymap	ms-	1.1.2
jupyter-renderers	ms-	1.1.0
vscode-jupyter-cell-tags	ms-	0.1.9
vscode-jupyter-slideshow	ms-	0.1.6
color-highlight	nau	2.8.0
vscode-conventional-commits	viv	1.26.0
better-comments	aar	3.0.2
vscode-kmonad	can	0.2.0
vscode-lark	dir	0.1.0
dotenv	mik	1.0.1
jupyter-keymap	ms-	1.1.2
remote-containers	ms-	0.401.0
remote-ssh	ms-	0.118.0
remote-ssh-edit	ms-	0.87.0
remote-wsl	ms-	0.88.5
vscode-remote-extensionpack	ms-	0.26.0
remote-explorer	ms-	0.4.3
remote-server	ms-	1.5.2
material-icon-theme	PKi	5.20.0
rewrap	stk	1.16.3
pdf	tom	1.2.2
errorlens	use	3.24.0
material-theme	zhu	3.19.0

(1 theme extensions excluded)

A/B Experiments

vsliv368cf:30146710
vspor879:30202332
vspor708:30202333
vspor363:30204092
vswsl492:30256859
pythonvspyt551cf:31249601
vscod805cf:30301675
binariesv615:30325510
py29gd2263:31024239
c4g48928:30535728
azure-dev_surveyone:30548225
962ge761:30959799
f8hc8238:30694864
2e7ec940:31000449
pythontbext0:30879054
cppperfnew:31000557
dwnewjupytercf:31046870
nativerepl2:31139839
pythonrstrctxt:31112756
nativeloc2:31192216
iacca1:31171482
5fd0e150:31155592
dwcopilot:31170013
6074i472:31201624
dwoutputs:31242946
customenabled:31248079
hdaa2157:31222309
copilot_t_ci:31222730
f5992895:31254866
jda6j935:31233686
fh1c7952:31256801
31787653:31256342

[karthiknadig]

Try the workarounds recommended here: microsoft/vscode-python#24699 (comment)

[diego-pm]

I tried the first option ("python.experiments.optOutFrom": ["pythonTerminalEnvVarActivation"]) and it worked. Then, I removed the setting again and tried the second option (executing the command Python: clear cache and reload window) and it also works. So clearing the cache seems to have permanently fixed the issue without having to opt out from the experiment. Thanks!

[karthiknadig]

@diego-pm Thanks for letting us know.

[Dynamith]

@karthiknadig I also found this bug and found the following phenomenon.
When applying multiple environment changes to the Integrated terminal, only the last Path change is retained.
The python extension package contains 2 environment path changes from ms-python.python and ms-python.debugpy.
By enabling the extensions in a different order, I found that the order of these two can also be changed in the Environment Changes page.
Then printing the terminal variable $env:Path, I found that only the path changed by the later extension is retained.
Could it be fixed?

[karthiknadig]

@Dynamith I am working on a fix for activations in the https://github.com/microsoft/vscode-python-environments extension. That extension supports uv for env creation, and package management. One thing we are looking into is to use activation mechanisms that doesn't involve us modifying the PATH from the extension. A issue that occurs with that approach is that the order of extension activation matters and can conflict as you have seen.

A work around for the above case is to add this to your user settings:

    "python.experiments.optOutFrom": ["pythonTerminalEnvVarActivation"]

That will cause the extension to send the command to the terminal for activation.