Python Debugger not attaching in V2025.14.0/V2025.14.1 and Breaking Debugging Functionality

[tulis-deshaw]

Description

The recent updates to the Python Debugger extension (ms-python.debugpy) from V2025.10.0 to V2025.14.0 and subsequently to V2025.14.1 are causing debugging issues for Python applications. The issue appears to be related to changes in the debugger attaching logic.

Environment Information

• Python Debugger extension versions tested:
  • V2025.10.0 (working)
  • V2025.14.0 (broken)
  • V2025.14.1 (broken)
• VSCode:

Version: 1.103.2 (system setup)
Commit: 6f17636121051a53c88d3e605c491d22af2ba755
Date: 2025-08-20T16:45:34.255Z
Electron: 37.2.3
ElectronBuildId: 12035395
Chromium: 138.0.7204.100
Node.js: 22.17.0
V8: 13.8.500258-electron.0
OS: Windows_NT x64 10.0.22631

• I use VSCode on my Windows machine, and ssh into a Linux host for development.

Error Details

When attempting to debug Python code, the following error occurs:

Output Tab:

2025-10-15 17:48:30.694 [info] Debugging using the editor button 'Debug in terminal'
2025-10-15 17:48:30.704 [info] Getting configurations for workspace
2025-10-15 17:48:30.706 [warning] Missing field in launch.json: version
2025-10-15 17:48:30.706 [info] Using configuration in launch.json
2025-10-15 17:48:31.627 [info] Using the only workspaceFolder found:  /codemill/tulis/test_pycharm
2025-10-15 17:48:31.640 [info] Resolving launch configuration with substituted variables
2025-10-15 17:48:31.640 [info] Using the only workspaceFolder found:  /codemill/tulis/test_pycharm
2025-10-15 17:48:31.776 [info] DAP Server launched with command: /usr/local/bin/python3 /u/tulis/.vscode-server/extensions/ms-python.debugpy-2025.14.0-linux-x64/bundled/libs/debugpy/adapter
2025-10-15 17:48:34.223 [info] Received 'debugpySockets' event from debugpy.
2025-10-15 17:48:34.229 [info] Received 'debugpySockets' event from debugpy.
2025-10-15 17:48:34.234 [info] Received 'debugpySockets' event from debugpy.

Terminal Error:

%  /usr/bin/env /usr/local/bin/python3 /u/tulis/.vscode-server/extensions/ms-python.debugpy-2025.14.0-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher 35469 -- /codemill/tulis/test_pycharm/src/python/maths/test_add.py 
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/u/tulis/.vscode-server/extensions/ms-python.debugpy-2025.14.0-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/__main__.py", line 92, in <module>
    main()
  File "/u/tulis/.vscode-server/extensions/ms-python.debugpy-2025.14.0-linux-x64/bundled/libs/debugpy/adapter/../../debugpy/launcher/__main__.py", line 44, in main
    host = sockets.get_default_localhost()
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: module 'debugpy.common.sockets' has no attribute 'get_default_localhost'

launch.json:

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

After a few seconds we get this error popup:

Can someone help me here to fix this?

[eleanorjboyd]

I think this might help: #830

[tulis-deshaw]

For now we are using the older version V2025.10.0, which seems to work. I had 2 questions:

1. Why this issue got caused after V2025.14.x?
2. When is it going to get fixed?

[eleanorjboyd]

@rchiodo would be able to answer better

[rchiodo]

Do you have your own version of debugpy installed?

This commit added that function:
microsoft/debugpy@34d5de9

Your error could happen if you have an older debugpy installed in your environment.

[tulis-deshaw]

We have version 1.6.6 installed using pip but when I run which debugpy, it shows the path from the Python Debugger Extension.

[rchiodo]

If debugpy is imported into the code somewhere, this would cause that problem. I recommend removing your pip version or updating it to the latest.