Invalid filter list URLs give "Out of date" message

[Stevoisiak]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality in the uAssets issue tracker.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO in the browser.
• I checked the documentation to understand that the issue I am reporting is not normal behavior.

I tried to reproduce the issue when...

• uBO is the only extension.
• uBO uses default lists and settings.
• using a new, unmodified browser profile.

Description

In AdGuard, if a user tries to add a webpage as a custom filter URL, (ex: https://github.com/Stevoisiak/Stevos-AI-Blocklist/blob/main/GenAI-Blocklist.txt), they are shown a descriptive error message explaining they need a direct link to the filter.

By contrast, in uBlock Origin these filter lists get added to the custom list without a visible message. There is are warning and broken chain icons, which when hovered over show tooltips for "Out of date" and "A network error prevented the resource from being updated". This may lead users to believe there is an internet issue, rather than informing them that the URL is incorrect.

A specific URL where the issue occurs.

extension://odfafepnkmbhccpbejgmiehpchacaeak/dashboard.html#3p-filters.html
https://github.com/Stevoisiak/Stevos-AI-Blocklist/blob/main/GenAI-Blocklist.txt

Steps to Reproduce

1. Open uBO filter lists menu
2. Scroll down and click Import
3. Enter URL https://github.com/Stevoisiak/Stevos-AI-Blocklist/blob/main/GenAI-Blocklist.txt and click Apply Changes

Expected behavior

uBlock Origin shows an error message that URL does not lead to a valid filter list file.

Troubleshooting information

uBlock Origin: 1.75.0
Chromium: 153
filterset (summary):
 network: 187611
 cosmetic: 120391
 scriptlet: 48922
 html: 0
listset (total-discarded, last-updated):
 removed:
  plowe-0: null
 added:
  https://github.com/Stevoisiak/Stevos-AI-Blocklist/blob/main/GenAI-Blocklist.txt: 0-0, never
  fanboy-cookiemonster: 47919-122, 6d.17h.46m
  ublock-cookies-easylist: 5846-107, 6d.17h.46m
  fanboy-social: 17953-27, 20h.34m
  fanboy-thirdparty_social: 69-0, 2d.17h.43m
  adguard-mobile-app-banners: 7991-19, 17h.34m
  easylist-newsletters: 9603-22, 6d.17h.46m
  easylist-notifications: 2551-447, 6d.17h.46m
 default:
  user-filters: 6-0, never
  ublock-filters: 53554-88, 2m Δ
  ublock-badware: 10255-17, 2m Δ
  ublock-privacy: 4160-3, 2m Δ
  ublock-unbreak: 2834-1, 2m Δ
  ublock-quick-fixes: 535-0, 2m Δ
  easylist: 91007-146, 2m Δ
  easyprivacy: 56695-49, 2m Δ
  urlhaus-1: 47055-6, 2h.34m
filterset (user): [array of 6 redacted]
trustedset:
 added: [array of 10 redacted]
 removed:
  chrome-extension-scheme
userSettings:
 advancedUserEnabled: true
 userFiltersTrusted: true
hiddenSettings:
 trustedListPrefixes: ublock- https://raw.githubusercontent.com/Stevoisiak/Stevos-GenAI-Blocklist/refs/heads/main/
supportStats:
 allReadyAfter: 819 ms (selfie)
 maxAssetCacheWait: 611 ms
 cacheBackend: indexedDB

[gorhill]

My view is that people who import lists need to take responsibility. This would require more time than I want to spend to surface such error to the user interface.