Sveltekit Sentry handler clobbers error messages in dev

[divmgl]

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/svelte

SDK Version

"@sentry/sveltekit": "^8",

Framework Version

Svelte 5

Link to Sentry event

No response

Reproduction Example/SDK Setup

Instrumenting Sveltekit results in error messages being clobbered in local dev. This means that I have to deploy different versions of my codebase to production than what's in development, which is not ideal. This happens even if Sentry is not enabled:

Sentry.init({
  dsn: /** DSN omitted */
  tracesSampleRate: 1,
  enabled: import.meta.env.PROD,
  environment: import.meta.env.PROD ? "prod" : "dev",
})


export const handle: Handle = sequence(Sentry.sentryHandle(), sequence(supabase, authGuard))
export const handleError = Sentry.handleErrorWithSentry()

Any error occurs on a +page.server.ts module, undefined gets printed to console rather than the actual error. It's happening with every error.

Steps to Reproduce

export const handle: Handle = sequence(Sentry.sentryHandle(), sequence(supabase, authGuard))
export const handleError = Sentry.handleErrorWithSentry()

Expected Result

Actual Result

[divmgl]

I've narrowed it down to this:

export const handleError = Sentry.handleErrorWithSentry()

[divmgl]

I was able to solve it like this:

const sentryHandleError = Sentry.handleErrorWithSentry()

export const handleError: HandleServerError = (props) => {
  if (import.meta.env.PROD) {
    return sentryHandleError(props)
  }

  console.error(props.error)
}

Still, not ideal.

[Lms24]

Hi @divmgl thanks for writing in! Before I try to reproduce this, did you follow our setup guide? It tells you to pass your error handler (where you print to the console) as a callback to Sentry.handleErrorWithSentry(). Let me know if this changes anything, thanks :)