Notify when all editors associated with a NotebookDocument have been closed

[DonJayamanne]

• VSCode Version: Master
• OS Version: Mac

Provide a way to determine when all editors associated with a NotebookDocument have been closed.

• Open file A.ipynb
• Open file A.ipynb again on the side.
• User saves A.ipynb as B.ipynb
• Now VSC Closes NotebookBookDocument A.ipyn (event fired notebook.onDidCloseNotebookDocument)
• This isn't correct, we still have NotebookDocument A.ipyn open, as we have another editor for this file remaining.

Suggestions

• Add a dispose method NotebookData.dispose, that will be invoked by VSC when all editors associated with that Notebook are closed.
  • Inline with Custom editors API.
  • This way we (extension authors) know when all editors associated with a document have been closed.
  • No need to rely on onDidCloseNotebookDocument (though this might still be useful for extension authors who do not provide NotebookContentProviders)

Why do we need this

• We need this to ensure the kernel state (in extension) is transitioned across to the new editor when possible.
• Scenario: Disposing kernel (when all editors are closed)
  • User opens A.ipynb file
  • User opens this notebook again (side by side)
  • User runs a cell
  • User closes one of the A.ipynb editors & VSC fires onDidCloseNotebookDocument
  • We assume all Notebook Editors associated with A.ipynb have been closed and we dispose the kernel.
  • However user still has another A.ipynb file
  • The kernel associate with an active notebook Editor A.ipynb is now in a bad state (running cells is now broken)
• Scenario: Similar to previous scenario (but with SaveAs)
  • User opens existing A.ipynb file
  • User has the same notebook opened twice (side by side)
  • User runs a cell
  • Users saves one of the editors as New.ipynb
  • At this point VSC closes one of A.ipyb editor and opens New.ipynb
  • VSC fires onDidCloseNotebookDocument for A.ipynb
  • We assume A.ipynb has been closed and dispose the kernel.
  • But we still have an editor for A.ipynb
• Scenario (user renames an nb file)
  • Again same as previous scenarios
  • We need to move kernel to new resource if user renames a file
  • This can be done only when we know for a fact that all editors associated with an nb have been closed.

Does this issue occur when all extensions are disabled?: Yes/No

@rebornix /cc

[rebornix]

This isn't correct, we still have NotebookDocument A.ipyn open, as we have another editor for this file remaining.

In latest Insiders, when a notebook file renamed, all editors attached in the editor pane will replace the old notebook document with the new one, in your particular case, there is no A.ipynb file open in the workspace anymore.