Does this issue occur when all extensions are disabled?: No, this issue is related to extension development

Version: 1.57.0-insider
Commit: b4c1bd0
Date: 2021-06-09T10:41:06.148Z
Electron: 12.0.9
Chrome: 89.0.4389.128
Node.js: 14.16.0
V8: 8.9.255.25-electron.0
OS: Darwin x64 19.6.0

CommentController can have commentingRangeProvider assigned. This provider is responsible for indicating where commenting ranges should be shown.

If the assignment happens after a delay (e.g. after API call), the commenting ranges are not shown in the active editor.

In the following video, I demonstrate the issue. I used the yeoman generated example extension and replaced the extension.ts with:

import * as vscode from 'vscode';

const createCommentingRangeProvider = (): vscode.CommentingRangeProvider => ({
  provideCommentingRanges: (document) => [
    new vscode.Range(
      new vscode.Position(0, 0),
      new vscode.Position(document.lineCount - 1, 0)
    ),
  ],
});

export async function activate(context: vscode.ExtensionContext) {
  const disposable = vscode.commands.registerCommand(
    'commenting-range-bug-demonstration.helloWorld',
    async () => {
      const commentController = vscode.comments.createCommentController(
        'id',
        'label'
      );
      // interruption here causes the bug
      await new Promise((res) => setTimeout(res, 100));
      commentController.commentingRangeProvider =
        createCommentingRangeProvider();
    }
  );

  context.subscriptions.push(disposable);
}

The video shows how having a delay between vscode.comments.createCommentController and commentController.commentingRangeProvider causes the active editor not to have commenting ranges.

I pushed the example extension to a public repository: https://gitlab.com/viktomas/demonstrate-commenting-ranges-bug/-/blob/master/src/extension.ts

This issue is an edge case and the fix could probably be just mentioning this bug in the JS Doc: https://github.com/microsoft/vscode/blob/main/src/vs/vscode.d.ts#L13448 I'm happy to create a PR.

The best fix would be either to make VS Code react to commentingRangeProvider being set on the CommentController or add commentingRangeProvider as an argument to the vscode.comments.createCommentController function call to signal that the commenting range provider must be ready at the time of creation