Environment

- Operating System: Linux 7.0.0
- Node.js: v24.15.0
- Nuxt: 4.6.1
- Nitro: 2.13.4
- Builder: vite@8.3.4
- Config: experimental.viewTransition: true
- Browsers: Chrome, Firefox

Reproduction

Minimal app with experimental.viewTransition: true:

<!-- app/pages/index.vue -->
<template>
  <NuxtLink to="/broken">Go to a page whose setup throws</NuxtLink>
</template>

<!-- app/pages/broken.vue -->
<script setup lang="ts">
await new Promise(resolve => setTimeout(resolve, 50))
throw createError({ status: 404, statusText: 'Not found', fatal: true })
</script>

<template>
  <div>never rendered</div>
</template>

Open /, click the link. The error page renders, and the console shows an unhandled promise rejection.

Describe the bug

When a client-side navigation that runs a view transition fails (router.onError, app:error or vue:error), view-transitions.client.ts aborts it with abortTransition(), which rejects the promise returned from the update callback with no reason. Per the View Transitions spec, a rejected update callback rejects updateCallbackDone as well as ready and finished. The plugin already catches finished (#34515) and ready (#35537), but updateCallbackDone stays unhandled, so the browser reports Uncaught (in promise) undefined.

This code path is not dev-only. Any navigation that fails during page setup triggers it.

Adding currentTransition.updateCallbackDone.catch(() => {}) next to the existing handlers fixes it. I verified this through a page:view-transition:start hook in the reproduction.

Additional context

No response

Logs

Uncaught (in promise) undefined