Black formatter connection to server erroring on "No such option: --stdio"

[operryman-kxs]

Type: Bug

Install Vs code, install black extension, error occurs

Extension version: 2025.2.0
VS Code version: Code 1.98.0 (6609ac3d66f4eade5cf376d1cb76f13985724bcb, 2025-03-04T21:06:18.612Z)
OS version: Windows_NT x64 10.0.19045
Modes:
Connection to 'ssh-remote+csd2' could not be established
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2
Remote OS version: Linux x64 5.15.167.4-microsoft-standard-WSL2

System Info

Item	Value
CPUs	Intel(R) Xeon(R) W-2133 CPU @ 3.60GHz (12 x 3600)
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)	127.73GB (104.04GB free)
Process Argv	--crash-reporter-id df779254-9b71-47e1-8918-ce702ff4a4fd
Screen Reader	no
VM	0%

Connection to 'ssh-remote+csd2' could not be established

Item	Value
Remote	WSL: Ubuntu-20.04
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	Intel(R) Xeon(R) W-2133 CPU @ 3.60GHz (12 x 0)
Memory (System)	62.67GB (58.71GB free)
VM	0%

Item	Value
Remote	WSL: Ubuntu-20.04
OS	Linux x64 5.15.167.4-microsoft-standard-WSL2
CPUs	Intel(R) Xeon(R) W-2133 CPU @ 3.60GHz (12 x 0)
Memory (System)	62.67GB (58.71GB free)
VM	0%

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dwcopilot:31170013
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[operryman-kxs]

2025-03-10 10:31:18.734 [info] [Error - 10:31:18 AM] Server process exited with code 2.
2025-03-10 10:31:18.734 [info] [Error - 10:31:18 AM] Server initialization failed.
2025-03-10 10:31:18.734 [info] Message: Pending response rejected since connection got disposed
Code: -32097
2025-03-10 10:31:18.734 [info] [Info - 10:31:18 AM] Connection to server got closed. Server will restart.
2025-03-10 10:31:18.734 [info] true
2025-03-10 10:31:18.734 [info] [Error - 10:31:18 AM] Black Formatter client: couldn't create connection to server.
2025-03-10 10:31:18.734 [info] Message: Pending response rejected since connection got disposed
Code: -32097
2025-03-10 10:31:18.930 [info] Usage: black [OPTIONS] SRC ...
Try 'black -h' for help.

Error: No such option: --stdio (Possible options: --diff, --fast, --version)

2025-03-10 10:31:19.295 [info] [Error - 10:31:19 AM] Server process exited with code 2.
2025-03-10 10:31:19.296 [info] [Error - 10:31:19 AM] Server initialization failed.
2025-03-10 10:31:19.296 [info] Message: Pending response rejected since connection got disposed
Code: -32097
2025-03-10 10:31:19.296 [info] [Error - 10:31:19 AM] The Black Formatter server crashed 5 times in the last 3 minutes. The server will not be restarted. See the output for more information.
2025-03-10 10:31:19.296 [info] [Error - 10:31:19 AM] Black Formatter client: couldn't create connection to server.
2025-03-10 10:31:19.296 [info] Message: Pending response rejected since connection got disposed
Code: -32097
2025-03-10 10:31:19.296 [info] [Error - 10:31:19 AM] Restarting server failed
2025-03-10 10:31:19.296 [info] Message: Pending response rejected since connection got disposed
Code: -32097

[karthiknadig]

@operryman-kxs Can you share your settings? also, run pip list in your environment?

[operryman-kxs]

settings.json
{
"python.testing.pytestArgs": [
"<redacted>"
],
"python.testing.unittestEnabled": false,
"python.testing.pytestEnabled": true,
}

pip list - I included black and all it's dependencies, but I think the full list of dependencies contains privacy concerns. Let me know if you need the versions of specific packages.

Package Version

---

black 25.1.0
click 8.1.8
mypy-extensions 1.0.0
packaging 24.2
pathspec 0.12.1
platformdirs 4.3.6
tomli 2.2.1
typing_extensions 4.12.2
aiohttp 3.11.11

[karthiknadig]

@operryman-kxs Something is strange here. The argument --stdio that we pass to our internal server is being passed black. I suspect somewhere one of the following settings is set to the wrong thing. black-formatter.interpreter or black-formatter.path.

In the initial part of the logs I have something like this:

2025-03-10 10:55:28.012 [info] Server run command: c:\GIT\misc\vscode-python-environments\.venv\Scripts\python.exe c:\Users\kanadig\.vscode-insiders\extensions\ms-python.black-formatter-2025.2.0\bundled\tool\lsp_server.py --stdio
2025-03-10 10:55:28.012 [info] Server: Start requested.
2025-03-10 10:55:28.012 [debug] Server State: Starting

do you see something like that in the logs. The way i see this can go wrong is if black-formatter.interpreter is set to black instead of some python path. then you would get:
black.exe c:\Users\kanadig\.vscode-insiders\extensions\ms-python.black-formatter-2025.2.0\bundled\tool\lsp_server.py --stdio

That would certainly show the error that you are seeing.

[operryman-kxs]

Yes you are correct, the black-formatter.interpreter was set to black, thanks, that solved it!