Fix for issue 1750-prevent re-execution of already running cell

[SsaiSanjanna03]

Fixes https://github.com/jupyter/notebook/issues/1750:Prevent concurrent cell executions in Jupyter Notebook.

Changes:

• Updated packages/notebook/src/actions.tsx to use metadata['running'] to block execution if a cell is running, logging "Cell is already running".
• Added UI test in ui-tests/tests/runcell.spec.ts to verify:
• • Single output for rapid cell executions.
• • Correct variable state (i == 1).
• • Console log for ignored requests.

Testing:

• Manually verified by rapid Shift+Enter on a long-running cell.

Related:

• Closes https://github.com/jupyter/notebook/issues/1750

Ready for review.

[github-actions]

👈 Launch a Binder on branch SsaiSanjanna03/notebook/prevent_cell__re_execute_issue1750

[krassowski]

I wonder if this should be behind an option as concurrent re-runing of a cell is sometimes intended, especially with async kernels.

[jtpio]

Closing as stale, and also because the proper place to implement such feature would be https://github.com/jupyterlab/jupyterlab, which Notebook depends on.

Please continue to the discussion in https://github.com/jupyterlab/jupyterlab or the related issue if still needed, thanks!