Debugger hangs and then silently exits

[thomaspheiffer]

Environment data

VS Code version: 1.19.0
Python Extension version: 0.9.1
Python Version: 3.6.3
OS and version: macOS High Sierra 10.13.2

Actual behavior

Debugger hangs when trying to step over a line of code instantiating an ITK vector object (seems to be a simple wrapper around a std::vector<>). Eventually the debugger silently stops with no other output.

Expected behavior

Debugger should step over this code and the ITK vector should be inspectable as an initialized vector of zeros. I believe this is a problem with the VSCode python extension because this code can be debugged in the same environment using Pycharm.

Steps to reproduce:

pip install itk==4.12.0.post1

Start debugger, run to break point on line 4. Attempt to step over to line 5. The debugger will then hang and eventually exit.

Logs

Output from Python output panel

Hello

Output from Console window (Help->Developer Tools menu)

The console in Developer Tools remains blank.

[DonJayamanne]

PTVSD library is crashing silently.

[DonJayamanne]

@thomaspheiffer
We've been working on a new debugger in the Python extension. Please could you try this out.

• Open launch.json
• Update the setting "type":"python" to "type":"pythonExperimental"

Let me know how that goes. Thanks.

[thomaspheiffer]

Hi @DonJayamanne,

I just gave it a shot, with this as my current setup:

VS Code version: 1.22.2
Python Extension version: 2018.4.0
Python Version: 3.6.3
OS and version: macOS High Sierra 10.13.4

Unfortunately, I still get a crash when I reproduce the steps above (set the breakpoint at the ITK vector and try to step over it).

However! This may actually not be a specific problem with the debugger(?). There is some additional output that gets printed to terminal compared to when I last tried this. Whether I use the old debugger or the experimental debugger, I get:

Hello
libc++abi.dylib: terminating with uncaught exception of type swig::stop_iteration
Abort trap: 6

I also just noticed that if I delete the breakpoint and still launch the script with Start Debugging using the same launch.json it runs to completion (for both old and new debugger):

Hello
Goodbye

This is all local debugging in a virtual environment using Python 3.6.3.

[DonJayamanne]

I've filed an issue upstream microsoft/ptvsd#414
The problem is with the debugger, i believe when attempting to evaluate the local variables (in this case itk_vector).

[DonJayamanne]

This has been resolved upstream.