Debugger 'hangs' when working with `pixi` environments

[irm-codebase]

Type: Bug

Behaviour

Attempting to run the debugger in pixi based projects (i.e., the environment is within the .pixi/default folder results in failures.

The debugger will 'hang' without showing any error or warning. This is new behaviour, as pixi projects did not have this problem before.

Steps to reproduce:

1. Use linux (I use Fedora 41)
2. Create a small projext via pixi init --format pyproject
3. In vscode, select default as the python environment for that project.
4. Write a dummy hello world script, put a breakpoint.

When debugging that file, you'll see the launcher 'hang'.

After a while you'll get the following:

Oddly enough, debugging works well for .ipydb files.

Diagnostic data

launch.json configuration

{
    // Use IntelliSense to learn about possible attributes.
    // Hover to view descriptions of existing attributes.
    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
    "version": "0.2.0",
    "configurations": [

        {
            "name": "Python Debugger: Current File",
            "type": "debugpy",
            "request": "launch",
            "program": "${file}",
            "console": "integratedTerminal"
        }
    ]
}

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

**2025-06-26 15:59:34.035 [info] Send text to terminal: /home/ivanruizmanuel/.pixi/bin/pixi shell --manifest-path /home/ivanruizmanuel/Documents/git/module_powerplants/pixi.toml
2025-06-26 16:00:28.133 [info] Send text to terminal: /home/ivanruizmanuel/.pixi/bin/pixi shell --manifest-path /home/ivanruizmanuel/Documents/git/module_powerplants/pixi.toml
2025-06-26 16:01:43.096 [info] Send text to terminal: /home/ivanruizmanuel/.pixi/bin/pixi shell --manifest-path /home/ivanruizmanuel/Documents/git/module_powerplants/pixi.toml
**

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

2025-06-26 16:00:27.865 [info] Debugging using the editor button 'Debug in terminal'
2025-06-26 16:00:27.867 [info] Getting configurations for workspace
2025-06-26 16:00:27.868 [info] Using configuration in launch.json
2025-06-26 16:00:27.956 [info] Using the only workspaceFolder found:  /home/ivanruizmanuel/Documents/git/module_powerplants
2025-06-26 16:00:27.993 [info] Resolving launch configuration with substituted variables
2025-06-26 16:00:27.993 [info] Using the only workspaceFolder found:  /home/ivanruizmanuel/Documents/git/module_powerplants
2025-06-26 16:00:28.002 [info] DAP Server launched with command: /home/ivanruizmanuel/Documents/git/module_powerplants/.pixi/envs/default/bin/python /home/ivanruizmanuel/.vscode/extensions/ms-python.debugpy-2025.8.0-linux-x64/bundled/libs/debugpy/adapter
2025-06-26 16:00:28.125 [info] Received 'debugpySockets' event from debugpy.
2025-06-26 16:00:28.127 [info] Received 'debugpySockets' event from debugpy.
2025-06-26 16:00:28.127 [info] Received 'debugpySockets' event from debugpy.

Extension version: 2025.8.0
VS Code version: Code 1.101.0 (dfaf44141ea9deb3b4096f7cd6d24e00c147a4b1, 2025-06-11T15:00:50.123Z)
OS version: Linux x64 6.14.9-200.fc41.x86_64
Modes:

• Python version (& distribution if applicable, e.g. Anaconda): 3.13.3
• Type of virtual environment used (e.g. conda, venv, virtualenv, etc.): Unknown
  Details

System Info

Item	Value
CPUs	13th Gen Intel(R) Core(TM) i7-13700H (20 x 3273)
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: disabled_software vulkan: disabled_off webgl: enabled webgl2: enabled webgpu: disabled_off webnn: disabled_off
Load (avg)	1, 1, 1
Memory (System)	15.24GB (9.02GB free)
Process Argv
Screen Reader	no
VM	0%
DESKTOP_SESSION	gnome
XDG_CURRENT_DESKTOP	GNOME
XDG_SESSION_DESKTOP	gnome
XDG_SESSION_TYPE	wayland

[eleanorjboyd]

Will give this a try, in the meantime have you determined if rolling back to a previous version helps resolve the issue since you said it is a regression?

[irm-codebase]

@eleanorjboyd I'm a tad lost here. Which component is a regression in my first comment?

[irm-codebase]

@eleanorjboyd is there any other information I can provide on this?

It's a tad difficult to debug my code without a proper debugger in place... If need be, I can move this issue to the appropriate repo. Just let me know.

[eleanorjboyd]

Hi sorry about my lack of response. I was wondering if you think this is a regression. Like if you have seen this change with a recent version or if you have never gotten this working in the past

[irm-codebase]

Ahhhh, ok. Apologies, I thought that my VSCode settings where out of sync.

Definitely a regression. I've worked with pixi for several projects and VSCode never showed this behaviour.
There is nothing in my settings (that I am aware of) that changed either. This just appeared with a recent update.

If you'd like detailed logs, or a repo where this problem can be reproduced, let me know!

[eleanorjboyd]

one other item to check is if you have the "python environments extension" installed and enabled. You can tell by looking for this python icon in your sidebar

[irm-codebase]

I did not!
Unfortunately, installing it does not really seem to solve anything... it does not even show on the side panel for some reason.

Screencast.From.2025-07-10.09-57-10.mp4

[irm-codebase]

@eleanorjboyd sorry for bothering, but is there any info on this?
This is turning to a big blocker on our side, unfortunately...

I see other issues with debug launches failing, so I think I'm not alone on this one.

• Running Python code directly is fine, but debugging reports an error debugpy#1925
• Debugger is making up its own virtualenv location and unable to run #746
• Python environment terminal activation breaks debugger launch vscode-python#25192 (comment)

If I can provide any other info or logs that could help you, let me know!

[irm-codebase]

In case it helps, I managed to get the debugger to work... in jupyter notebooks???

Basically, it only fails for regular python files... which is quite wacky. We're not going to convert all our code to notebooks, so this is still a blocker, unfortunately.

[renan-r-santos]

I have the same issue. I tried a few things and posted my findings here in case it helps getting this fixed.

[ignition5]

i find if you use starship and pixi, this problem will arise, but there is no problem with p10k.So i think maybe starship PS1 or other environment variable settings conflict with vscode-python-debugger