Slug generation crashing with slow network speeds

[dm-lars]

Bug description

When typing into the title field of a collection entry, statamic will make calls to /cp/slug to generate the slug for the slug field. However, when the request is taking too long and you continue typing, the slug request gets cancelled and a new request is fired. This logic seems to crash something and the slug field stops updating.

How to reproduce

1. Set Throttling in Chrome to something slow like 3G
2. Visit https://demo.statamic.com/cp/collections/pages/entries/create
3. Start typing a long title, make some weird pauses while typing
4. Observe the network tab in Chrome and the slug field on the right to see the error

Logs

Environment

Environment
Application Name: Ruebe Statamic
Laravel Version: 12.54.1
PHP Version: 8.4.18
Composer Version: 2.9.5
Environment: local
Debug Mode: ENABLED
URL: ruebe-statamic.ddev.site
Maintenance Mode: OFF
Timezone: UTC
Locale: de

Cache
Config: NOT CACHED
Events: NOT CACHED
Routes: NOT CACHED
Views: CACHED

Drivers
Broadcasting: log
Cache: file
Database: mariadb
Logs: stack / daily
Mail: smtp
Queue: sync
Session: file

Storage
public/storage: NOT LINKED

Livewire
Livewire: v4.2.1

Sentry
Enabled: YES
Environment: local
Laravel SDK Version: 4.21.1
PHP SDK Version: 4.21.0
Release: NOT SET
Sample Rate Errors: 100%
Sample Rate Performance Monitoring: 100%
Sample Rate Profiling: NOT SET
Send Default PII: ENABLED

Statamic
Addons: 6
Sites: 1
Stache Watcher: Enabled (auto)
Static Caching: Disabled
Version: 6.5.0 PRO

Statamic Addons
aryehraber/statamic-captcha: 1.16.0
marcorieser/statamic-livewire: 5.2.1
studio1902/statamic-peak-seo: 10.0.0
thoughtco/statamic-cache-tracker: 2.2.1

Installation

Other (please explain)

Additional details

Can be reproduced in the Statamic 6 Demo as well

[dm-lars]

Here's what Claude had to say about it:

The fix is two changes in Slug.js:

1. #performRequest() line 121: Changed return; to throw e; — Cancelled requests now reject instead of resolving with undefined. Previously, swallowing the cancellation error caused the promise to resolve with undefined, which propagated up and set this.slug = undefined in Slugify.vue.

2. #debounced callback line 43-44: Changed .catch((e) => reject(e)) to only reject for non-cancellation errors. Cancellation rejections are silently ignored, so the old promise simply stays pending and gets garbage collected. This prevents unhandled promise rejections.

The root cause: When typing during an in-flight request, AbortController.abort() cancelled the HTTP request, but the .catch in #performRequest returned undefined instead of re-throwing. This undefined resolved through the promise chain into Slugify.vue where this.slug = undefined was set, breaking the slug field's auto-generation.