Pylance not starting, Pylance: report issue...` doesn't work

[hrl20]

SincePylance: report issue... doesn't work, i've created an issue under vscode-python through Python: report issue...
microsoft/vscode-python#24839
Here's a copy of the report

---

Type: Bug

Behaviour

Pylance intellisense is completely not working (go to reference/definition even for the standard python library).

Running the Python: Restart Language server command results in command 'python.analysis.restartLanguageServer' not found

After selecting an interpreter (./.venv/bin/python), opening a terminal shows
Python virtual environment was successfully activated, even though "(.venv)" indicator may not be present in the terminal prompt. Learn more. However, if I try to call python it would still fail zsh: command not found: python

I've tried uninstall and reinstalling the extensions at least 10 times. Including deleting the python-related folders from the ~/.vscode/extensions folder.

Now i'm trying the disable/reenable/unintsall/reinstall loop again, and this time, when i click enable in the Python extension, i get this error about Pylance:

notificationsAlerts.ts:40 Error: Cannot enable 'Pylance' extension because it depends on 'Python' extension that cannot be enabled
    at R3e.L (extensionEnablementService.ts:181:12)
    at R3e.J (extensionEnablementService.ts:157:8)
    at R3e.setEnablement (extensionEnablementService.ts:207:10)
    at async Lit.nc (extensionsWorkbenchService.ts:2925:10)

Developer tools sometimes has some error message: notificationsAlerts.ts:42 Sorry, something went wrong activating IntelliCode support for Python. Please check the "Python" and "VS IntelliCode" output windows for details. c @ notificationsAlerts.ts:42

Steps to reproduce:

Just install the regular Python + Python debugger + Pylance. Try selecting interpreter. Observe everything fail miserably.

Extension version: 2025.0.0
VS Code version: Code 1.97.2 (Universal) (e54c774e0add60467559eb0d1e229c6452cf8447, 2025-02-12T23:20:35.343Z)
OS version: Darwin arm64 22.6.0
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.11.11
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Venv
• Value of the python.languageServer setting: Default

User Settings

languageServer: "Jedi"

Installed Extensions

Extension Name	Extension Id	Version
cmake	twx	0.0.17
cmake-tools	ms-	1.20.52
copilot	Git	1.272.0
copilot-chat	Git	0.24.1
cpptools	ms-	1.23.6
cpptools-extension-pack	ms-	1.3.0
cpptools-themes	ms-	2.0.0
gitlens	eam	16.3.2
go	gol	0.44.0
intellicode-api-usage-examples	Vis	0.2.9
java	red	1.39.0
js-debug	ms-	1.97.1
js-debug-companion	ms-	1.1.3
jupyter	ms-	2025.1.0
jupyter-keymap	ms-	1.1.2
jupyter-renderers	ms-	1.1.0
python	ms-	2025.0.0
rust-analyzer	rus	0.3.2308
vscode-gradle	vsc	3.16.4
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-maven	vsc	0.44.0
vscode-mojo	mod	25.1.1
vscode-tailwindcss	bra	0.14.6
vscodeintellicode	Vis	1.3.2

System Info

Item	Value
CPUs	Apple M2 Max (12 x 2400)
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 webgl: enabled webgl2: enabled webgpu: enabled webnn: disabled_off
Load (avg)	2, 2, 3
Memory (System)	32.00GB (0.10GB free)
Process Argv	--crash-reporter-id ce3d937f-6e61-4cb4-ad2a-b73c62e87442
Screen Reader	no
VM	0%

A/B Experiments

vsliv368:30146709
vspor879:30202332
vspor708:30202333
vspor363:30204092
vscod805:30301674
binariesv615:30325510
py29gd2263:31024239
c4g48928:30535728
azure-dev_surveyonecf:30548226
962ge761:30959799
f8hc8238:30694864
2e7ec940:31000449
pythontbext0:30879054
cppperfnew:31000557
dwnewjupytercf:31046870
nativerepl1:31139838
pythonrstrctxt:31112756
nativeloc1:31192215
iacca1:31171482
5fd0e150:31155592
dwcopilot:31170013
stablechunks:31184530
6074i472:31201624
dwoutputs:31242946
customenabled:31241370
hdaa2157:31222309
copilot_t_ci:31222730
jda6j935:31233686

---

Environment data

• Pylance version: 2025.2.1
• OS version: Darwin arm64 22.6.0
• Python version (& distribution if applicable, e.g. Anaconda): 3.11.11 (/opt/homebrew/bin/python3.11)

Code Snippet

Try to run Pylance: report issue...
See this in devtools

workbench.desktop.main.js:sourcemap:711 [Extension Host] stack trace: Error: command 'python.viewLanguageServerOutput' not found
    at f3e.n (vscode-file://vscode-app/Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:1288:1341)
    at f3e.executeCommand (vscode-file://vscode-app/Applications/Visual%20Studio%20Code.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:1288:1273)
Ats @ workbench.desktop.main.js:sourcemap:711
$logExtensionHostMessage @ workbench.desktop.main.js:sourcemap:711
S @ workbench.desktop.main.js:sourcemap:3242
Q @ workbench.desktop.main.js:sourcemap:3242
M @ workbench.desktop.main.js:sourcemap:3242
L @ workbench.desktop.main.js:sourcemap:3242
(anonymous) @ workbench.desktop.main.js:sourcemap:3242
B @ workbench.desktop.main.js:sourcemap:29
fire @ workbench.desktop.main.js:sourcemap:29
fire @ workbench.desktop.main.js:sourcemap:732
l.onmessage @ workbench.desktop.main.js:sourcemap:3253
workbench.desktop.main.js:sourcemap:34   ERR command 'python.viewLanguageServerOutput' not found

[hrl20]

For posterity, I looked at the Python extension outputs, and found out that the extension picked up some really old, no longer functional python installation in my environment.

Send text to terminal: /usr/local/bin/python3.5 <home>/.vscode/extensions/ms-python.python-2025.0.0-darwin-arm64/python_files/printEnvVariablesToFile.py <home>/.vscode/extensions/ms-python.python-2025.0.0-darwin-arm64/python_files/deactivate/zsh/envVars.txt
2025-02-23 15:24:20.245 [info] Starting Pylance language server.
2025-02-23 15:24:49.497 [error] Failed to initialize deactivate script /opt/homebrew/bin/zsh Error: "<home>/.vscode/extensions/ms-python.python-2025.0.0-darwin-arm64/python_files/deactivate/zsh/envVars.txt" file not created
    at Timeout.<anonymous> (<home>/.vscode/extensions/ms-python.python-2025.0.0-darwin-arm64/out/client/extension.js:2:311758)
    at listOnTimeout (node:internal/timers:581:17)
    at processTimers (node:internal/timers:519:7)

Removing the bad python installation allowed the extension pick up an actually valid python to start the language server.

I have never had to look at extension outputs until this, and so it didn't occur to me that they actually existed in the output tabs. IMO, that was a clear error message that should have been surfaced to the user.

[bruecksen]

@hrl20 I have the same issue only with a new project. In my old projects the language server is working. I also tried to setup a clean project. It has the same issue. Python interpreter is selected but pylance is not starting. Anyone any idea what i can do to make this work?

[hrl20]

@bruecksen have you checked the Python extension output in the output tab?

[bruecksen]

@hrl20 i don't have Python extension as an option in the output tab. Only Extension Host. Do you mean that? If i compare my Python output to the project where it is working it is missing the activation of the environment.

Python output (pylance not working)

2025-02-27 08:21:12.451 [info] Experiment 'pythonRecommendTensorboardExt' is active
2025-02-27 08:21:12.451 [info] Experiment 'pythonTerminalEnvVarActivation' is active
2025-02-27 08:21:12.451 [info] Experiment 'pythonTestAdapter' is active
2025-02-27 08:21:12.451 [info] Native locator: Refresh started
2025-02-27 08:21:12.451 [info] Native locator: Refresh started
2025-02-27 08:21:12.508 [info] Python interpreter path: ~/.virtualenvs/ut/bin/python

Python output (pylance working)

2025-02-27 08:21:12.897 [info] Experiment 'pythonRecommendTensorboardExt' is active
2025-02-27 08:21:12.897 [info] Experiment 'pythonTerminalEnvVarActivation' is active
2025-02-27 08:21:12.897 [info] Experiment 'pythonTestAdapter' is active
2025-02-27 08:21:12.897 [info] Native locator: Refresh started
2025-02-27 08:21:12.908 [info] > pyenv which python
2025-02-27 08:21:12.908 [info] cwd: .
2025-02-27 08:21:14.527 [info] Python interpreter path: ~/.virtualenvs/lifelessons/bin/python
2025-02-27 08:21:14.885 [info] > . ~/.virtualenvs/lifelessons/bin/activate && echo 'e8b39361-0157-4923-80e1-22d70d46dee6' && python ~/.vscode/extensions/ms-python.python-2025.1.2025022501-darwin-arm64/python_files/printEnvVariables.py
2025-02-27 08:21:14.885 [info] shell: bash
2025-02-27 08:21:14.924 [info] > /usr/local/bin/python3 ~/.vscode/extensions/ms-python.python-2025.1.2025022501-darwin-arm64/python_files/printEnvVariables.py
2025-02-27 08:21:14.924 [info] shell: bash
...

[hrl20]

this is slightly different from my issue i think. i would try removing ~/.virtualenvs/ut/bin/python, if they were the same issue.

[bruecksen]

@hrl20 hmm ok. it sounded more or less the same. Is your language server starting do you see this in the python output? I tried all the different python environments. New ones, existing ones. nothing helped.

[debonte]

@hl20, can this issue be closed? The vscode-python team is looking at microsoft/vscode-python#24839 which seems like a duplicate of this issue to me.