debugpy.listen fails in VS Code terminal

[samjijina]

After the latest release of VSCode, my debugging workflow has broken down due to the new feature "No‐Config Debugging". I would like to disable this feature as I use the pip installed and managed debugpy.

(My workflow is on a cluster managed by Slurm and VSCode's debugpy does not work well. Further, I use Anaconda to manage my python env)

[karthiknadig]

@samjijina How are you running the debugger? the no-config debugger should only impact you if you run debugpy <script> but if you run python -m debugpy <script> it should still use the one that is installed in your environment.

[samjijina]

@karthiknadig
I am running it using the following command:
python -m debugpy --listen 0.0.0.0:1239 --wait-for-client <file_name.py>

Further, I get the same error even in an interactive python interpreter (such as IPython):

$ which debugpy
~/.conda/envs/<env_name>/bin/debugpy
$ which python
~/.conda/envs/<env_name>/bin/python

[karthiknadig]

When importing the debugpy will come from the sys.path. Can you try this?

> import debugpy
> debugpy.__file__

Here is what I see from the terminal, where the no-config debug is enabled:

The first command shows that debugpy as a command works. Then I do a import debugpy from the same environment, and it does not work. Then I install debugpy and try import debugpy again. I was checking here to ensure that we were not accidentally adding the build-in debugpy to PYTHONPATH in terminal. If you try the above and it says site-packages then the issue is that debugpy itself might be failing for you.

[samjijina]

debugpy works fine when I use it in a non-VSCode terminal. For example, in the image below I am using Ubuntu's terminal with a SSH connection to a node in my cluster:

However, the error is occurring when using VSCode's terminal as shown in the image below:

Here are the environment contributors in VSCode:

[karthiknadig]

As far as I can tell, none of those contributors interfere. As you can see the debugpy here is coming from the site-packages, the one that is loaded is the one that is being used. I can think of two things that could cause issues when running from VS Code terminal, 1) port forwarding, 2) shell integration.

Try disabling these settings, and see if that helps:

[samjijina]

I disabled both those settings but the error still persists.

[karthiknadig]

Transferring this to debugpy to investigate while it is failing with File not found when doing debugpy.listen in VS Code Terminal.

[rchiodo]

I get a similar error in a VS code terminal (only in the stable version):

>>> import debugpy
>>> debugpy.listen(5678)
0.01s - Debugger warning: It seems that frozen modules are being used, which may
0.00s - make the debugger miss breakpoints. Please pass -Xfrozen_modules=off
0.00s - to python to disable frozen modules.
0.00s - Note: Debugging will proceed. Set PYDEVD_DISABLE_FILE_VALIDATION=1 to disable this validation.
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\Users\rchiodo\source\repos\pyrx-3\.venv\Lib\site-packages\debugpy\public_api.py", line 31, in wrapper
    return wrapped(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\rchiodo\source\repos\pyrx-3\.venv\Lib\site-packages\debugpy\server\api.py", line 132, in debug
    log.reraise_exception("{0}() failed:", func.__name__, level="info")
  File "C:\Users\rchiodo\source\repos\pyrx-3\.venv\Lib\site-packages\debugpy\server\api.py", line 130, in debug
    return func(address, settrace_kwargs, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\rchiodo\source\repos\pyrx-3\.venv\Lib\site-packages\debugpy\server\api.py", line 258, in listen
    raise RuntimeError(str(endpoints["error"]))
RuntimeError: Can't listen for client connections: [WinError 10013] An attempt was made to access a socket in a way forbidden by its access permissions

I just switch to a different port and it works.

>>> debugpy.listen(5679)
('127.0.0.1', 5679)

[rchiodo]

We'd need a callstack for the FileNotFoundError. I can't reproduce that exact problem myself.

[rchiodo]

I don't think this is a debugpy problem though. VS code must be doing something to interfere with opening ports in those terminals.

[samjijina]

could you share how to obtain the callstack for debugpy's listen()?

[rchiodo]

I believe the log should show error. If you turn on logging, the pydevd.log file may have the callstack for the real exception it.

That should be the log_to api.

import debugpy
debugpy.log_to('/file/path/to/write/logs')

[samjijina]

@rchiodo Thanks! Attaching three log files that were generated

debugpy.adapter-2346338.log

debugpy.pydevd.2346305.log

debugpy.server-2346305.log

[rchiodo]

That's pointing to here:
https://github.com/microsoft/debugpy/blob/fb0b06cab161478db95420c5bfb485c39d508f62/src/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py#L422

Which I believe is the first spot we write a response to VS code. My guess is that the port is only allowing reading and not writing for some reason.

[samjijina]

Also just wanted to mention, this issue is only showing up recently (within the last few days). I believe either the latest VSCode update or Python extension(s) updates are causing an issue since my debugging workflow and debugging commands have not changed.

[rchiodo]

@karthiknadig I had not looked at the adapter log, but this might just be a symptom of the other error. It has this though:

             Traceback (most recent call last):
               File "/storage/home/hcoda1/5/sjijina3/.conda/envs/cross_sim/lib/python3.11/site-packages/debugpy/adapter/__main__.py", line 115, in main
                 with open(listener_file, "w") as f:
                      ^^^^^^^^^^^^^^^^^^^^^^^^
             FileNotFoundError: [Errno 2] No such file or directory: '/tmp/noConfigDebugAdapterEndpoints-31c0910148b7927444e5/debuggerAdapterEndpoint.txt'

[rchiodo]

@karthiknadig This would only be true if DEBUGPY_ADAPTER_ENDPOINTS is set? Are you guys setting that in the terminal?

[rchiodo]

Actually, that might be causing the other error. If the adapter exits, we'd also get the error in the pydevd log. So mabye this isn't a socket problem, but a debugger extension issue.

[karthiknadig]

@rchiodo shouldn’t Debugpy have a try except around this? If the file does not exist then it should not crash. From the extension side we add this env variable since we can only do this once. The variable is maintained across restart, otherwise user has to reload terminal each time.

We do need to add a way to turn this off. @eleanorjboyd can you look into adding a setting to turnoff no-config debugging.

[rchiodo]

@rchiodo shouldn’t Debugpy have a try except around this? If the file does not exist then it should not crash.

Not sure I agree. If you're setting this environment variable, then you must want to use it. What should it do instead? Just act like it wasn't set? Output a warning?

Outputting a warning seems okay.

[samjijina]

@karthiknadig @rchiodo Python Debugger extension version 2025.0.1 (released 2025-02-12, 17:04:48) solved the issue. Not sure what changed but the error is gone.

[karthiknadig]

debugpy deletes the DEBUGPY_ADAPTER_ENDPOINTS file via atexit handler, successive sessions in the same terminal can fail. With the no config debugging we restore the file after it is deleted. But when users run this is not restored.

See here:
https://github.com/microsoft/debugpy/blob/ed9f2949f65a78036da6241c31615c001e943041/src/debugpy/adapter/__main__.py#L116

[karthiknadig]

@samjijina We had to solve a different but related problem. Looks like it might have mitigated the issue. If this issue is not occurring for you, you can close this.

@rchiodo We can discuss deletion/try except here #613 . The issue stems from simultaneous connection with different terminals on the same project.

[tekumara]

This is still happening to me using

Name: Python Debugger
Id: ms-python.debugpy
Description: Python Debugger extension using debugpy.
Version: 2025.4.0
Publisher: Microsoft
VS Marketplace Link: https://marketplace.visualstudio.com/items?itemName=ms-python.debugpy

eg: inside a vscode terminal:

❯ .venv/bin/debugpy --help
debugpy 1.8.13
See https://aka.ms/debugpy for documentation.

Usage: debugpy --listen | --connect
               [<host>:]<port>
               [--wait-for-client]
               [--configure-<name> <value>]...
               [--log-to <path>] [--log-to-stderr]
               <filename> | -m <module> | -c <code> | --pid <pid>
               [<arg>]...

❯ .venv/bin/debugpy --listen 62888 --wait-for-client -m app
object address  : 0x104fc9f40
object refcount : 2
object type     : 0x1049e8f90
object type name: FileNotFoundError
object repr     : FileNotFoundError(2, 'No such file or directory')
lost sys.stderr

If I run from a non-vscode terminal its fine.

[tekumara]

Running this in the vscode terminal seems to fix it:

unset DEBUGPY_ADAPTER_ENDPOINTS

But I have to run that everytime I start a vscode terminal.

[samjijina]

This issue has reappeared for me on version 2025.4.0 of the Python Debugger extension

[samjijina]

Running this in the vscode terminal seems to fix it:

unset DEBUGPY_ADAPTER_ENDPOINTS

But I have to run that everytime I start a vscode terminal.

This works for me too

[tibordecamargo]

I also started getting this issue when updating to 1.98.0 on a Mac M3 Pro, also with debugpy 1.8.13.

Unfortunately unset DEBUGPY_ADAPTER_ENDPOINTS did not solve the issue for me.

Debugpy also works fine outside the vscode terminal.

[eleanorjboyd]

Hi- investigating issue where unset DEBUGPY_ADAPTER_ENDPOINTS fixes the problem.

@tibordecamargo can you elaborate since your issue is different? (repro steps, versions, expected / actual behavior)