RegEx stack parsing 1s+ main thread block

[FabianKoder]

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)

Which SDK are you using?

@sentry/nextjs

SDK Version

10.43.0

Framework Version

No response

Link to Sentry event

No response

Reproduction Example/SDK Setup

No response

Steps to Reproduce

I have overwritten the global error handler and this seems to be the error that is thrown that produces massive main thread work:

[
 "ResizeObserver loop completed with undelivered notifications.",
 "https://example.com/example/url",
 0,
 0,
 null
]

The root cause according to the performance tab analysis seems to be the RegEx \S*Error: trying to parse the stack frame. Maybe the problem is that the thrown error is not in an expected format?

Expected Result

Unexpected / unparseable errors should not stall the browser to a halt.

Actual Result

Additional Context

If any more info is needed, I am happy to assist.

Priority

_{React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.}

[linear-code]

JS-2028

[chargome]

Hey @FabianKoder

I have overwritten the global error handler

Are you calling Sentry.captureException manually from there? Also can you share your client side init code?

[FabianKoder]

Hi @chargome, sorry for being unclear. I just overrode the global error handler to see the actual error that is causing this because it wasn't logged anywhere - even though we log every error in beforeSend. When it is not overridden, the error is caught by the global error handler, which causes that behavior.

This is the minimal reproduction init:

Sentry.init({
	dsn: process.env.NEXT_PUBLIC_SENTRY_DSN,
	environment: getEnvironment(), // not relevant
	integrations: [
		Sentry.thirdPartyErrorFilterIntegration({
			behaviour: 'apply-tag-if-contains-third-party-frames',
			filterKeys: ['...'],
		}),
	],
	beforeSend: (event, hint) => {
		console.error((hint.originalException || hint.syntheticException) ?? event); // <-- No log for this error somehow?
		return event;
	},
});

After crafting the minimum reproduction, I came to the conclusion that it is the result of the thirdPartyErrorFilterIntegration. Commenting that out resolves the issue. First idea is that it maybe only happens in the experimental Turbopack version?

I apologize for the originally sparse report, I am a little time constrained at the moment - hopefully you have more relevant data points now :)

[chargome]

I came to the conclusion that it is the result of the thirdPartyErrorFilterIntegration

Thanks for the hint! I'll take a look, but if you could provide some minimal reproduction for the setup that would be amazing!