OSX: JupyterLab debugger doesn’t work with xeus-python #679
Description
Summary
When using xeus-python as the kernel, the JupyterLab debugger freezes as soon as a breakpoint is hit. The code pauses, but the debugger never updates — no variables, no stack, nothing. The UI becomes stuck until the kernel is interrupted.
Screen.Recording.2025-12-06.at.23.32.26.mp4
Steps to Reproduce
- Open JupyterLab.
- Create a new notebook.
- Select xeus-python as the kernel.
- Open the Debugger panel.
- Click Enable Debugger.
- Add the following code in a cell
- Set a breakpoint on any line
- Execute the code cells
Code snippet for testing convenience
def inner(n):
if n <= 0:
return 0
return n + inner(n - 1)def outer(n):
x = inner(n)
return x * 2result = outer(3)
result