'Redirect' captured as exception with keys: location, status

[RaniSputnik]

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/sveltekit

SDK Version

9.35.0

Framework Version

Sveltekit 2.17.1

Link to Sentry event

No response

Reproduction Example/SDK Setup

RaniSputnik/sentry-issues@redirect-captured-as-exception

Steps to Reproduce

Redirect using the Sveltekit server handle hook. Eg.

import { sequence } from '@sveltejs/kit/hooks';
import { handleErrorWithSentry, sentryHandle, initCloudflareSentryHandle } from '@sentry/sveltekit';
import { redirect, type Handle } from '@sveltejs/kit';

const redirectToSentryPage: Handle = async ({ event, resolve }): Promise<Response> => {
	if (!event.request.url.includes("sentry")) {
		return redirect(303, "sentry-example-page");
	}
	return resolve(event)
}


// If you have custom handlers, make sure to place them after `sentryHandle()` in the `sequence` function.
export const handle = sequence(
	initCloudflareSentryHandle({ /* dsn etc */ }),
	sentryHandle(),
	redirectToSentryPage,
);

// If you have a custom error handler, pass it to `handleErrorWithSentry`
export const handleError = handleErrorWithSentry();

Deploy to Cloudflare workers. (I haven’t tested whether this impacts other adaptors eg. Vercel)

Visit a page that triggers a redirect (eg. /foo in my example repo).

Expected Result

No error is captured by Sentry.

Actual Result

An error is captured by Sentry with the message 'Redirect' captured as exception with keys: location, status.

It also seems like the issue fingerprint is changed by the path of the user and exactly when the redirect was raised, so this ends up having quite a large impact on our production instance. Multiple issues are opened for the same root cause:

[Lms24]

Hey again @RaniSputnik, thanks for reporting! Taking a look at your reproduction (much appreciated, thank you!) and will report back.

[Lms24]

The issue here is indeed Cloudflare specific because the initCloudflareSentryHandle function internally adds a wrapper around the cloudflare worker request handler. This wrapper was originally designed to be used in pure Cloudflare worker functions, so it also captures errors and sends them to Sentry. However, because it isn't tailored to SvelteKit, it doesn't filter out thrown redirect(...)s.

I also noticed that this sometimes caused errors being caught twice, once by the CF handler, once by sentryHandle.

I'll open a PR to fix this. Probably gonna add an option to the wrapper to opt out of capturing errors, meaning, we'll let the SvelteKit SDK handle this.

[Lms24]

I opened #16852 and #16853 to fix this. Thanks a lot for reporting!