API gaps to support Liveshare in Notebook

[rebornix]

Currently the editing API for Notebook is slim and may not support all features of Live Share.

[rebornix]

Below is a draft list of missing API/features to support co-editing in notebook after analyzing how LiveShare uses text editor APIs.

• Editor
  • 🏃 Visible notebook editors & change event(together with visible text editors) (vscode.window.visibleTextEditors, vscode.window.onDidChangeVisibleTextEditors)
  • Notebook editor selection & text editor selection in cell editor (vscode.window.onDidChangeTextEditorSelection). Track the selection changes in a document (E.g. highlights, cursor position)
  • Active notebook editor change (vscode.window.onDidChangeActiveTextEditor). Handle changes in currently active editor and sync with other participants.
  • Editor visible range change (vscode.window.onDidChangeTextEditorVisibleRanges). Update layout info if other participants are following current user.
    • visible range of viewport
    • reveal range
• Document
  • 🏃 Notebook document changes event (vscode.workspace.onDidChangeTextDocument). Collect & process actual edits to a document
    • Need to figure out what's the best practice for listening to both notebook changes and cell document changes
  • Notebook document, open, close event (vscode.workspace.onDidCloseTextDocument, vscode.workspace.onDidOpenTextDocument). Clean up states.
  • Notebook document save event (vscode.workspace.onDidSaveTextDocument)
    • Saves need to be propagated through the session, so other clients can also save when indicated (guests aren't really saving, for example)
• Navigation
  • Open/jump to an editor (vscode.window.showTextDocument).
  • Open/jump to a diff editor (vscode.diff)
  • Unfold recursively to top level on a position
• Decorations
  • Show user card/info around the editor/cell selection
• Undo/Redo
  • Notebook document change events + cell document change events
  • 🏃 Hook up with editor undo/redo command (undo, redo)
• MISC
  • Untitled notebook document (TextDocument.isUntitled)

cc @lostintangent

[lostintangent]

@rebornix Would there be work left for Live Share to do after you make the above changes? Or would notebooks magically "look" like a series of documents to Live Share? 😄 This might be a silly question, I just wanted to check, so we could plan ahead 👍

[rebornix]

@lostintangent Since the notebook editor/documents are new concepts, it won't work out of the box after we make above changes. Live Share at least needs to

• Co-editing. It may need to leverage fluid to handle the conflict resolution of notebooks as the notebook documents are structured objects other than plain text.
• Navigation. It needs to understand the difference between TextEditor/TextDocument & NotebookEditor/Document.