SIGSEGV in app.publish() / app.numSubscribers() without calling App.ws to define a WebSocketContext

[jed]

I'm getting segfaults when I try to publish to a topic to which no subscription has been issued.

It's a pretty simple repro, basically boils down to (more descriptive repro attached).

import { App } from 'uWebSockets.js';
App().listen(8451, () => App().publish('never', 'hi'));  // exit 139

repro-uws-segfault.js

[uNetworkingAB]

Ah, I see the issue.

If you call App.ws to define a WebSocket context, the TopicTree is created. If you have not called App.ws to define a WebSocket context, the library basically disables all WebSocket based calls.