MaxListenersExceededWarning due to Sentry.init calls on window refresh

[Rafatcb]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Electron SDK Version

4.20.0

Electron Version

22.3.27

What platform are you using?

Windows

Link to Sentry event

No response

Steps to Reproduce

1. Add a call to Sentry.init on renderer. (I'm using React, so this is called outside the App component)
2. Refresh the page a few times (probably 10~15 times).

Expected Result

No warning.

Actual Result

Warning:

(node:19700) MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 message listeners added to [Worker]. Use emitter.setMaxListeners() to increase limit

If you add process.on('warning', e => console.warn(e.stack)) on your main process you can see the stack trace:

MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 destroyed listeners added to [EventEmitter]. Use emitter.setMaxListeners() to increase limit
    at _addListener (node:events:587:17)
    at EventEmitter.addListener (node:events:605:10)
    at EventEmitter.once (node:events:649:8)
    at IpcMainImpl.<anonymous> (D:\repo\node_modules\@sentry\electron\src\src\main\ipc.ts:268:14)
    at IpcMainImpl.emit (node:events:513:28)
    at IpcMainImpl.emit (node:domain:489:12)
    at EventEmitter.<anonymous> (node:electron/js2c/browser_init:2:81099)
    at EventEmitter.emit (node:events:513:28)
    at EventEmitter.emit (node:domain:489:12)

Which points to this part of Sentry's code:

sentry-electron/src/main/ipc.ts

Lines 259 to 272 in 02322af

	ipcMain.on(IPCChannel.RENDERER_START, ({ sender }) => {
	const id = sender.id;
	// In older Electron, sender can be destroyed before this callback is called
	if (!sender.isDestroyed()) {
	// Keep track of renderers that are using IPC
	KNOWN_RENDERERS = KNOWN_RENDERERS || new Set();
	KNOWN_RENDERERS.add(id);
	sender.once('destroyed', () => {
	KNOWN_RENDERERS?.delete(id);
	});
	}
	});

I think it could be updated to:

if (!sender.isDestroyed()) { 
 // Keep track of renderers that are using IPC 
 KNOWN_RENDERERS = KNOWN_RENDERERS || new Set(); 

+ if (KNOWN_RENDERERS.has(id)) {
+   return;
+ }

 KNOWN_RENDERERS.add(id); 

 sender.once('destroyed', () => { 
   KNOWN_RENDERERS?.delete(id); 
 }); 
} 

[timfish]

Hi @Rafatcb, thanks for reporting this!

[Rafatcb]

@timfish thanks for the fix 😃