🐛 BUG: execution freezes on `debugger` statements when no inspector is open

[dario-piotrowicz]

Which Cloudflare product(s) does this pertain to?

Wrangler, Miniflare

What versions are you using?

wrangler@3.106.0

What operating system and version are you using?

macOS Sequoia 15.2

Please provide a link to a minimal reproduction

https://github.com/dario-piotrowicz/my-create-cloudflare-worker-29-01-2025

Describe the Bug

Just adding a single debugger statement to a worker causes the whole process to freeze and not serve responses anymore, the only way to unblock execution is to open a devtools inspector

The way I reproduced this was by simply creating a worker using C3 (dario-piotrowicz/my-create-cloudflare-worker-29-01-2025@3996954), adding a debugger statement to my worker (dario-piotrowicz/my-create-cloudflare-worker-29-01-2025@95c7bb7) and running npm start, in such case requests don't get processed until I open an inspector that lets me hit the debugger.

Please provide any relevant error logs

No response

[dario-piotrowicz]

I think I know what's causing this

Wrangler sends a Debugger.enable message as soon as it connects with the Runtime websocket:

workers-sdk/packages/wrangler/templates/startDevWorker/InspectorProxyWorker.ts

Lines 385 to 388 in 19a19e9

	this.sendRuntimeMessage(
	{ method: "Debugger.enable", id: this.nextCounter() },
	runtime
	);

So workerd believes that it does have an inspector client attached (by logging the inspector messages I can indeed see a 'Debugger.paused' message sent from the runtime websocket even when no inspector client is attached).

To address this I think we should be more precise at to when we send the 'Debugger.enable' message and should only send it when an inspector client actually connects to the websocket (Note: I think I saw that both chrome://inspect actually and vscode already send a 'Debugger.enable' message upon connection, so I am not sure if we actually need to do it manually)