Refs: microsoft/vscode-jupyter#5607

• macOS @isidorn
• linux @gregvanl
• windows @bamurtaugh

Complexity: 3

Authors: @roblourens, @DavidKutu

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Setup

• Use VS Code Insiders and the latest jupyter and python extensions
• Make sure that you have python 3.7 or greater installed and on your path as python3 or python
• Set up a python virtualenv:

mkdir jupyter-dbg
cd jupyter-dbg
python3 -m venv ipykernel-env

• Activate the virtual environment

Mac/Linux:

source ipykernel-env/bin/activate

Windows:

ipykernel-env\Scripts\activate.bat

• Install the latest version of ipykernel in the virtual environment, which has debugging support

pip install ipykernel
python3 -m ipykernel install --user

• Open a .ipynb notebook file (You can use this one if you need one)
• Pick the kernel from your virtual env
• Set "jupyter.logging.level": "verbose"

Testing

• Click the RBL button
  
• It should stop execution on the first code line, the RBL button should change to Run Next Line, and another button called Continue Execution should appear next to it
  
• Clicking Run Next Line should step into the next line, stepping into functions defined in the same cell, but not stepping into anything else (functions in other cells, other python files, other python packages, etc.)
• Clicking Continue Execution should stop RBL, and continue executing the cell where it left off
• Interrupting or Restarting the kernel should also stop RBL

More Testing

• Use the cell toolbar on both positions, check that the Run by Line button doesn't move when you press it
• Check on the panel, that Jupyter: Variables comes up and that your variables get updated after each step
• Try using it only with the key bindings (each button shows how to do it)

Filing issues

File issues on the jupyter repo using the link above. Include the log from the Jupyter output channel

Known Issues

• Pop up appears after clicking RBL immediately after Run All (Stuck VS Code window when starting RBL when other cells are already running vscode-jupyter#7638). If you repro, please add logs, environment and repro steps (if they are different)
• Can't check for ipykernel 6 on remote (Can't check for ipykernel 6 on remote kernel  vscode-jupyter#7576)
• If you delete a cell (and then bring it back with ctrl + z) while its running, it thinks its still running