Python 3.14 Debugging : PYTHONPATH causing hang

[frbelotto]

Hi guys!
Last days I was playing around the new python 3.14 bug I simply can´t run any script in debug mode!

Take a look!
Just a simple code!

from pydantic import BaseModel
class a(BaseModel):
    test: str
print("test")

But a simple execution using vs code debbuging

Tools:

[rchiodo]

Sorry but I can't seem to reproduce your problem.

Works fine for me with 3.14:

What does your launch.json look like? Did you disable 'justMyCode'? That might be an internal exception that's being caught by Pydantic.

[frbelotto]

I´ve noticed that the error does not happen on local machine but happens when I am using WSL.
There isn´t a launch.json file. it's not created (at least at the project folder)

[frbelotto]

Is there any advance log I can try to get?

[rchiodo]

If you create a launch.json, you can tell it to log to file:

{
  // 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",
      "subProcess": true,
      "logToFile": true
    }
]
}

That should generate a bunch of log files in the same folder that the ms-python.vsdebug extension is located on the WSL machine. For me that's under ~/.vscode-server/extensions/<name of debugpy extension>

[frbelotto]

Hi!
Using just my code as false, those are the log output! The code is "stuck" and does not finish (or raise error). I had to stop the debugger to generate the files.

debugger.vscode_6c922ceb-2b76-40a7-974a-293be0217635.log
debugpy.adapter-6115.log
debugpy.launcher-6124.log
debugpy.pydevd.6129.log
debugpy.server-6129.log

This is the file where it gets stuck

[frbelotto]

And if I use just my code as true, those are the outputs. Now, the code crashes with the earlier reported error.

debugger.vscode_ff5a7fbb-b9be-4533-a2ad-41eb4ef9d481.log
debugpy.adapter-7673.log
debugpy.launcher-7682.log
debugpy.pydevd.7687.log
debugpy.server-7687.log

[rchiodo]

The NotImplementedException with justMyCode false is expected.

This is the callstack of the hang without justMyCode=true:

0.00s -   Stack: /home/frbelotto/.local/share/uv/python/cpython-3.14.0-linux-x86_64-gnu/lib/python3.14/posixpath.py, basename, 171
0.00s -   Stack: /home/frbelotto/.vscode-server/extensions/ms-python.debugpy-2025.14.1-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/../../debugpy/../debugpy/common/log.py, get_environment_description, 335
0.00s -   Stack: /home/frbelotto/.vscode-server/extensions/ms-python.debugpy-2025.14.1-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/../../debugpy/../debugpy/common/log.py, describe_environment, 372
0.00s -   Stack: /home/frbelotto/.vscode-server/extensions/ms-python.debugpy-2025.14.1-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/../../debugpy/../debugpy/server/cli.py, run_file, 355
0.00s -   Stack: /home/frbelotto/.vscode-server/extensions/ms-python.debugpy-2025.14.1-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/../../debugpy/../debugpy/server/cli.py, main, 508
0.00s -   Stack: /home/frbelotto/.vscode-server/extensions/ms-python.debugpy-2025.14.1-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/../../debugpy/__main__.py, <module>, 71
0.00s -   Stack: /home/frbelotto/.local/share/uv/python/cpython-3.14.0-linux-x86_64-gnu/lib/python3.14/runpy.py, _run_code, 88
0.00s -   Stack: /home/frbelotto/.local/share/uv/python/cpython-3.14.0-linux-x86_64-gnu/lib/python3.14/runpy.py, _run_module_as_main, 198

The spot where it's hanging is here:

I would hazard a guess something in your PYTHONPATH is not readable and that's what the problem is.