VS Code Debugger Freezes When Using wrap_wsgi_app with debugpy
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Assessment
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Newbie friendliness
- 38/100
Research direction
Start with the sample project’s main.py, especially lines 5, 6, and 8, and launch its included “wsgiref” debug configuration under Python 3.13. Reproduce the breakpoint freeze with curl, then trace the interaction between wrap_wsgi_app(app) and debugpy. Done means breakpoints focus the source line, debugger controls respond, and the HTTP request completes after resuming.
Written by the indexing model from the issue text.
Description
Environment data
- debugpy version: XXX (run
import debugpy; print(debugpy.__version__)if uncertain)1.8.13 - OS and version:
- Python version (& distribution if applicable, e.g. Anaconda):
Virtualenv
Python: 3.13.4
Implementation: CPython
Platform: linux
OS: posix
Python: 3.13.4
Path: /home/tony/.pyenv/versions/3.13.4
Executable: /home/tony/.pyenv/versions/3.13.4/bin/python3.13
- Using VS Code
Actual behavior
- VS Code debugger gets stuck once breakpoint is hit.
- UI does not switch to source code line.
- Debugger controls (Resume, Step Out, etc.) are unresponsive.
- HTTP server hangs (no response).
- However, the VS Code CALL STACK shows status: "PAUSED".
Expected behavior
- Debugger pauses on the specified line and focuses editor on source code.
- Debugger controls should remain fully functional.
- Upon resuming, the HTTP server should respond correctly:
HTTP/1.0 200 OK
Content-Length: 13
Content-Type: text/plain
Date: Wed, 11 Jun 2025 20:54:32 GMT
Server: WSGIServer/0.2 CPython/3.13.4
Hello world!
Steps to reproduce:
- Clone the sample project: https://github.com/totobest/python-debug-test
- Setup Python interpreter and install venv (poetry configuration is included)
- Launch the included "wsgiref" debug configuration..
- Set a breakpoint on line 5 or 6 of main.py..
- In a terminal, run:
curl -i localhost:8000
Additional Context
- Issue occurs consistently across Python versions 3.9 to 3.13.
- Tested across multiple Python Debugger extension versions (2024.x to latest).
- Works as expected when no breakpoint is set.
- Removing the call to
wrap_wsgi_app(app)(line 8) resolves the issue entirely.
- Dominant language
- Python
- Stars
- 2.5k
- Forks
- 202
- Avg merge
- 5d 1h
- Merged PRs (30d)
- 1
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
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