SaveAs functionality in Notebook API

[DonJayamanne]

Assume we have the following scenario:

• NotebookA has been opened twice (side by side)
  • It is my understanding that extension authors need not worry about how many editors are opened for the same document.
  • Thats great
• User starts executing all cells in NotebookA
• Now user saves one of them as NotebookB.
• At this point one of the Notebook is NotebookA and other is NotebookB & both are opened.

Questions

• When invoking saveNotebookAs, will VS Code provide a completely new instance of NotebookDocument with Uri pointing to the new target resource?
  • I think it should.
  • Else updates to this NotebookDocument could impact both NotebookA and NotebookB
• However creating a copy of NotebookDocument & passing this into saveNotebookAs might not always work
  • If user has just one notebook opened, then creating a copy will not work as output will not go into this same document (with different file name) while cells are being executed.
  • Feels like we should create copies only when there's one copy of the editor opened for a notebook document.
• Other approaches,
  • Extension can disable stop execution when user performs a saveas.
    • However, we end up with similar situation as earlier.
    • We shouldn't stop execution if there is only one editor for NotebookA opened.
  • VS Code can disable save as while execution is in progress (don't think this is a good idea - not allowing user to save a file is just wrong)

@rebornix /cc

& thanks for the awesome work done by the VS Code team for adding this API.

[DonJayamanne]

@rebornix
I'm closing this issue. Considering the fact that this will line up with Custom Editor and looking at existing behavior in Notebooks, I think we can handle this at our end (I'll file a separate issue for some other stuff).
From what I can tell the following happens:

• User hits Save as
• VS Code will close previous editor and open a new editor for the new target

This works for us, except we need to know whether editors associated with old file are still opened. Separate issue