fix: memory leak in QuickDiffModel

[SimonSiefke]

Before (Typing in editor 197 times):

When typing into the editor 197 times, it seems that the number of QuickDiffModel functions increases by one each time.

The json lists src/vs/workbench/contrib/scm/browser/quickDiffModel.ts:232:10 as source:

this._diffDelayer
	.trigger(async () => {
		const result: { allChanges: QuickDiffChange[]; changes: QuickDiffChange[]; mapChanges: Map<string, number[]> } | null = await this.diff();

		const editorModels = Array.from(this._originalEditorModels.values());
		if (!result || this._disposed || this._model.isDisposed() || editorModels.some(editorModel => editorModel.isDisposed())) {
			return; // disposed
		}

		this.setChanges(result.allChanges, result.changes, result.mapChanges);
	})
	.catch(err => onUnexpectedError(err)); // here

After registering the _diffDelayer disposable, the issue seems to be resolved.

JSON Data Details

{
  "namedFunctionCount3": [
    {
      "count": 203,
      "delta": 203,
      "name": "anonymous",
      "sourceLocation": "vscode-file://vscode-app/workspace/vscode-memory-leak-finder/.vscode-test/vscode-linux-x64-1.103.2/resources/app/out/vs/workbench/workbench.desktop.main.js:569:18762",
      "originalLocation": "src/vs/workbench/contrib/comments/browser/commentsController.ts:710:11",
      "originalName": "CommentController.beginComputeCommentingRanges"
    },
    {
      "count": 203,
      "delta": 203,
      "name": "anonymous",
      "sourceLocation": "vscode-file://vscode-app/workspace/vscode-memory-leak-finder/.vscode-test/vscode-linux-x64-1.103.2/resources/app/out/vs/workbench/workbench.desktop.main.js:569:18902",
      "originalLocation": "src/vs/workbench/contrib/comments/browser/commentsController.ts:715:7",
      "originalName": "CommentController.beginComputeCommentingRanges"
    },
    {
      "count": 203,
      "delta": 203,
      "name": "anonymous",
      "sourceLocation": "vscode-file://vscode-app/workspace/vscode-memory-leak-finder/.vscode-test/vscode-linux-x64-1.103.2/resources/app/out/vs/workbench/workbench.desktop.main.js:430:48674",
      "originalLocation": "src/vs/editor/contrib/folding/browser/folding.ts:344:23",
      "originalName": "unknown"
    },
    {
      "count": 203,
      "delta": 203,
      "name": "anonymous",
      "sourceLocation": "vscode-file://vscode-app/workspace/vscode-memory-leak-finder/.vscode-test/vscode-linux-x64-1.103.2/resources/app/out/vs/workbench/workbench.desktop.main.js:527:23529",
      "originalLocation": "src/vs/workbench/contrib/scm/browser/quickDiffModel.ts:232:10",
      "originalName": "QuickDiffModel"
    }
  ],
  "isLeak": true
}

[DonJayamanne]

Wait, I think i may have been too quick
Let me have another look

[DonJayamanne]

Yes its fine, i had to have another look as we already do some disposing work in the dispose method (line 500).
However we will first cancel this ThrottleDelayer and then dispose of it, hence its fine.