Add onWillSaveNotebookDocument

[mjbvz]

This would match onWillSaveTextDocument but for notebook docs instead

As parts of this, we should allow extensions to perform notebook edits before the save happens

[jrieken]

Is anyone asking for this specifically?

[mjbvz]

@Yoyokrazy and I discussed as a way to clean up unused attachments in notebooks. For this we need to loop through all attachments in the notebook and remove them from the metadata if they are not referenced in the cell's markdown

We also talked about cleaning up these attachments when the notebook is closed. However that means we would need an api to modify notebooks when they are closed, which raises many more questions

[worksofliam]

@jrieken I am asking for it! It'd be very useful, thanks!

Related PR/issue: codefori/vscode-ibmi#818 (comment)

[jrieken]

@bpasero do we have a generic save participants for any working copy? onWillSaveTextDocument is done via ITextFileService.files.addSaveParticipant but for notebook we need something same, same but different

[bpasero]

@jrieken yeah I think I had added that even though no client yet, can you try via IWorkingCopyFileService.addSaveParticipant and IWorkingCopyFileService.runSaveParticipants.

[mjbvz]

Note from API discussion: when looking into this, we should also look into format on save for notebooks

[seeM]

We would use this in nbdev (tracking here: AnswerDotAI/nbdev#952). We remove unneeded metadata from notebooks on-save, for cleaner diffs and less chance of merge conflicts. It's very easy to implement with Jupyter Notebook/Lab via ContentsManager.pre_save_hook. We add this to the relevant config file:

def nbdev_clean_jupyter(**kwargs):
    try: from nbdev.clean import clean_jupyter
    except ModuleNotFoundError: return
    clean_jupyter(**kwargs)

c.ContentsManager.pre_save_hook = nbdev_clean_jupyter

How could we get similar behaviour for our VSCode users? Is there any workaround while onWillSaveNotebookDocument doesn't exist?

[rebornix]

We introduced a proposed api onWillSaveNotebookDocument this month and plan to finalize the API in April. It would be great if you can give that a try and provide feedbacks. To test proposed api, you can follow https://code.visualstudio.com/api/advanced-topics/using-proposed-api . The shape of onWillSaveNotebookDocument is as below

	export interface NotebookDocumentWillSaveEvent {
		/**
		 * A cancellation token.
		 */
		readonly token: CancellationToken;

		/**
		 * The document that will be saved.
		 */
		readonly document: NotebookDocument;

		/**
		 * The reason why save was triggered.
		 */
		readonly reason: NotebookDocumentSaveReason;

		waitUntil(thenable: Thenable<readonly WorkspaceEdit[]>): void;

		waitUntil(thenable: Thenable<any>): void;
	}

Additional edits before save can be returned through waitUntil.

[rebornix]

Latest API https://insiders.vscode.dev/github/microsoft/vscode/blob/d3c2dcacf39c2a25c06547945ae13da4c8cf9f82/src/vscode-dts/vscode.proposed.notebookDocumentWillSave.d.ts

[rebornix]

Based on the comment from @mjbvz , we can simply the API to

	export interface NotebookDocumentWillSaveEvent {
		/**
		 * A cancellation token.
		 */
		readonly token: CancellationToken;

		/**
		 * The document that will be saved.
		 */
		readonly document: NotebookDocument;

		/**
		 * The reason why save was triggered.
		 */
		readonly reason: TextDocumentSaveReason;

		waitUntil(thenable: Thenable<readonly WorkspaceEdit>): void;

		waitUntil(thenable: Thenable<any>): void;
	}

Two changes:

• Reuse TextDocumentSaveReason despite the name is talking about TextDocument, it's generic and applied to all documents
• Use single WorkspaceEdit as it can contain multiple edits already, also we can validate if the workspace edit is only applied in the target notebook document or its cells

[rebornix]

The API is finalized and merged into vscode.d.ts.