Python Debug no longer works on container

[guilhermehartmann]

Describe the bug
VSCode is unable to debug python code when inside of a container, used to work until a few months ago. Now I get the error "Failed to spawn launcher: [Errno 13] Permission denied: '/workspace/project_a'

Steps/Code to reproduce bug
Build a DevContainer with a python project and try to debug from the unit test tab, it works from other places

Expected behavior
Debug should just work as usual

Environment overview (please complete the following information)

Environment location: Docker
using pytest and trying to debug a test case.
Environment details
Just using conda from the rapids container, nothing particular

Additional context

[zyassine]

I got the same issue today

[NeilAthe]

me too

[NeilAthe]

I think the MS extension 'Python Environments' had a bug and a fix was just released. Mine's working this morning.

[jamie-sgro]

On August 11th after the Python extension update to 2025.12.0 (though that might not be the root cause, just coincided), I noticed the IDE's built-in test-explorer fails in debug mode with the same error code. This error wasn't unique to docker on my machine and it's worth noting running a test without debug mode in the IDE works fine, and running the debugger on whole python files still works. It's just the 'Debug Test' option specifically.

I just updated the Python Environments extension to 1.3.12261011 (Aug 14th) but to no avail.

[eleanorjboyd]

Hello everyone, sorry to hear this! Does uninstalling the python environments extension or downgrading the version of the debugger extension fix the problem?

[guilhermehartmann]

Indeed, downgrading solved the problem.

[eleanorjboyd]

I think the MS extension 'Python Environments' had a bug and a fix was just released. Mine's working this morning.

which version are you on now which are working?

[guilhermehartmann]

I have tested with Python Plugin v2024.22.0

[chris-demattio-keysight]

I was running into this bug completely independent of containers. I am using pytest with Conda environments and I would hit this error every time I tried to use the "Debug Test at Cursor" functionality. One day it was working and the next day it did not. I lost so much time trying to figure out what I did to break it. It never occurred to me to suspect that one of the Python extensions broke it. :-(

Based on the comments in this thread, I updated all of my python extensions to the latest versions this morning and, like magic, everything worked again. Judging by the "Last Released" dates on my extensions, it looks like it was the Python Environments plugin that did the trick (I have v1.2.0 installed currently).

[eleanorjboyd]

There are a few things that could be happening here:

1. The python environment extension (which is under an experiment and set to 20% of users) messed up your interpreter selection and therefore doesn't work
2. Your path has a space in it which the python environment extension currently messes up (another bug I am in the process of fixing)
3. a change in the recent version of the python extension caused this

If people facing issues can try disabling the python environments extension, while keeping all other extension versions updated, and see if that fixes it and let me know that will help narrow down the issue. Thanks

[chris-demattio-keysight]

@eleanorjboyd : For the record, my Conda environment path did not have any spaces. It did have a dash, however, if that matters.

[eleanorjboyd]

I did a big fix around conda activation in general- a rewrite of the process so maybe it is that fix that you got which helped