Assigning undefined to commentThread.contextValue doesn't reset the backing context key

[hunterknepshield]

• VS Code Version: 1.54.3 (commit 2b9aebd)
• OS Version: macOS 11.3 Beta

Steps to Reproduce:

1. From package.json, have a menu contribution registered for comments/commentThread/context to show some command with "when": "commentThread != sentinelForPackageJson"
2. From extension, call commentController.createCommentThread
3. Leave the thread's contextValue unassigned for now
4. Observe that the command from package.json is currently visible in a comment thread; type a reply and click the button for that command
5. Within the handling code for that command, assign the thread's contextValue to "sentinelForPackageJson" (similar to the example extension in microsoft/vscode-extension-samples/blob/main/comment-sample/src/extension.ts when handling mywiki.startDraft). My extension also sets the thread's canReply value to false at the same time.
6. Have another command to effectively discard the comment created with the prior command. It will set the thread's canReply value to true and set its contextValue to undefined. Observe that in this case, the command from 1 is not rendered, but the textbox to type a reply has reappeared.

I've been playing around with it, and if instead of setting the contextValue to undefined in step 6, I set some other random arbitrary value, then the context key is updated correctly and the command does reappear. I believe it has something to do with the slight difference in commentThreadWidget.ts, specifically around _commentThreadContextValue:

		if (this._commentThread.contextValue) {
			this._commentThreadContextValue.set(this._commentThread.contextValue);
		} else {
			this._commentThreadContextValue.reset();
		}

Using the inspect context keys tool, the commentThread context key is still set to "sentinelForPackageJson", even though the object's property is definitely undefined after the command in 6 runs. For some reason, it seems the lifecycle of the comment thread is latching on to "sentinelForPackageJson" as the default value, even though it wasn't assigned anywhere near the thread's creation time, and was only done so later after user action had taken place + the thread was updated to append a new comment.

Does this issue occur when all extensions are disabled?: No

This is an extension I've been writing.

[vscodebot]

(Experimental duplicate detection)
Thanks for submitting this issue. Please also check if it is already covered by an existing one, like:

• Only show current thread in Run Panel (#113506)

[roblourens]

Seems like I can still repro this. If I set contextValue to undefined in the second command, the button doesn't show up again, but if I set it to some value, it does show up again.

[rebornix]

@roblourens can you check the context keys for the buttons and share the value of commentThread? Also can you share your code snippet?

[roblourens]

I added a second button so I can get the context of the menu, and it seems like sentinelForPackageJson is not set after running through the steps. Code looks roughly like this

	let thread: vscode.CommentThread;
	context.subscriptions.push(vscode.commands.registerCommand('extension.helloWorld', async (arg1) => {
		const commentController = vscode.comments.createCommentController(
			'id',
			'label'
		);
		const comment: vscode.Comment = {
			body: 'body',
			author: {
				name: 'name',
			},
			mode: vscode.CommentMode.Preview
		};
		thread = commentController.createCommentThread(vscode.window.activeTextEditor.document.uri, new vscode.Range(new vscode.Position(0, 0), new vscode.Position(0, 0)), [comment]);
		thread.contextValue = 'sentinelForPackageJson';
		thread.canReply = false;
});

	context.subscriptions.push(vscode.commands.registerCommand('extension.helloWorld2', async (arg1) => {
		thread.canReply = true;
		thread.contextValue = undefined;
	}));

[rebornix]

@roblourens I didn't quite follow the issues you ran into. Did you mean that after running "hello World", the context key for the comment thread is not set to sentinelForPackageJson?

[roblourens]

I run the first command helloWorld, everything is correct, then I run the second command helloWorld2, and the button should show up now that the contextValue has cleared but the button does not show up.