Applying some of the regional lists produces error

[85czt]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality by using the chat icon in the popup panel.
• 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 Lite in the browser.

I tried to reproduce the issue when...

• uBO Lite is the only extension.
• using a new, unmodified browser profile.

Description

with an amount of lists already enabled, trying to enable one of the several large regional lists gives Error: Invalid call to declarativeNetRequest.updateEnabledRulesets(). Failed to apply rules.
just appeared in the latest version (2026.301.2014)
Safari 18.7.3
ipad mini 2024
ipados 18.7.3

A specific URL where the issue occurs.

(extension settings - Filter lists)

Steps to Reproduce

1. enable all lists except the regional lists, wait for the spinner to finish spinning
2. enable AdGuard Chinese or AdGuard Français or potentially some other larger lists
3. issue appears and list fails to get applied

Expected behavior

the regional filter gets applied after the spinner finish spinning

Actual behavior

gives Error: Invalid call to declarativeNetRequest.updateEnabledRulesets(). Failed to apply rules. and the change is not applied

Troubleshooting information

name: uBlock Origin Lite
version: 2026.301.2014
browser: Safari 18.7 (ios)
filtering:
 default: complete
permission: all
rulesets:
 +adguard-mobile
 +annoyances-ai
 +annoyances-cookies
 +annoyances-notifications
 +annoyances-others
 +annoyances-overlays
 +annoyances-social
 +annoyances-widgets
 +block-lan
 +ublock-experimental
 +ubol-tests
 easylist
 easyprivacy
 pgl
 ublock-badware
 ublock-filters
scripting:
 ublock-badware.main
 ubol-tests.main
 css-user
 ublock-experimental.main
 adguard-mobile.main
 adguard-mobile.isolated
 css-generic-some
 annoyances-social.isolated
 annoyances-cookies.main
 css-generic-all
 ublock-filters.isolated
 annoyances-notifications.main
 easyprivacy.main
 annoyances-cookies.isolated
 css-generichigh
 annoyances-overlays.main
 annoyances-others.main
 easyprivacy.isolated
 annoyances-others.isolated
 annoyances-overlays.isolated
 ublock-experimental.isolated
 css-specific
 annoyances-notifications.isolated
 ublock-filters.main
 css-procedural

[85czt]

By the way if you disable all lists and enable AdGuard Chinese only it works fine. this is why I think it’s not a filter list issue

[gorhill]

There are internal limitations in Safari when enabling too many lists, uBOL just relays the error triggered inside Safari when enabling too many lists. For now you will have to choose first the lists which matters the most to you. These issues do not exist with Chromium or Firefox-based browsers -- or at least the limitations do not trigger with only few lists.

[mycodedoesnotcompile2]

Hello there,

I encounter the same bug and I don't think it is related to "regional" lists.

I think there is a regression because on an iPhone 14 with the latest iOS version, the 2026.201.1924 UBOL works flawlessly:

Details

name: uBlock Origin Lite
version: 2026.201.1924
browser: Safari Mobile 26.3 (ios)
filtering:
 default: optimal
permission: all
rulesets:
 +annoyances-ai
 +annoyances-cookies
 +annoyances-notifications
 +annoyances-others
 +annoyances-overlays
 +annoyances-social
 +annoyances-widgets
 adguard-mobile
 easylist
 easyprivacy
 fra-0
 pgl
 ublock-badware
 ublock-filters
scripting:
 easyprivacy.main
 ublock-badware.main
 css-procedural
 annoyances-others.isolated
 annoyances-overlays.isolated
 adguard-mobile.main
 adguard-mobile.isolated
 css-specific
 annoyances-social.isolated
 ublock-filters.isolated
 annoyances-cookies.main
 ublock-filters.main
 fra-0.main
 annoyances-cookies.isolated
 annoyances-notifications.isolated
 fra-0.isolated
 annoyances-notifications.main
 annoyances-overlays.main
 annoyances-others.main
 easyprivacy.isolated

Whereas I encounter the same OP bug on another iPhone 14 with the exact same UBOL configuration than above, with the latest iOS version, but with a more recent UBOL version 2026.301.2014 giving the bug :

Details

name: uBlock Origin Lite
version: 2026.301.2014
browser: Safari Mobile 26.3 (ios)
filtering:
 default: optimal
permission: all
rulesets:
 +annoyances-ai
 +annoyances-cookies
 +annoyances-notifications
 +annoyances-others
 +annoyances-overlays
 adguard-mobile
 easylist
 easyprivacy
 fra-0
 pgl
 ublock-badware
 ublock-filters
scripting:
 easyprivacy.main
 ublock-badware.main
 css-procedural
 annoyances-others.isolated
 annoyances-overlays.isolated
 adguard-mobile.main
 adguard-mobile.isolated
 css-specific
 ublock-filters.isolated
 annoyances-cookies.main
 ublock-filters.main
 fra-0.main
 annoyances-cookies.isolated
 annoyances-notifications.isolated
 fra-0.isolated
 annoyances-notifications.main
 annoyances-overlays.main
 annoyances-others.main
 easyprivacy.isolated

Any ETA for fixing this bug ?
Thanks!

[gorhill]

Any ETA for fixing this bug ?

It's a Safari-specific issue, read the comment above yours.

[mycodedoesnotcompile2]

Any ETA for fixing this bug ?

It's a Safari-specific issue, read the comment above yours.

If I understand correctly, this is a rule number limit in Safari ? If so:

• 1. How can you explain that this bug is not present in the UBoL version 2026.201.1924, but present in the version 2026.301.2014 ?
• 2. Do you have even a rough estimation of the value of the limit ? FYI I managed to successfully reached 26 741 rules in the 2026.301.2014 version

Thank you

[gorhill]

I don't know if it's a rule number or whatever else -- Safari just refuses to register the rules and returns a generic error message.

How can you explain

I cannot explain it. Safari can make changes to its internal code used to convert DNR rules to its content blocking rule format, it's out of control of uBO. Ultimately the proper fix for Safari is to ensure its internal content blocking rule syntax is a straightforward match to the DNR rule syntax, which is not currently the case and causes many Safari-specific issues. At best we try to mitigate by fine-tuning filters but there is a limit to what we can do.

Bottom line is that there is nothing wrong with the DNR rules, they all work just fine in other browsers, this is a Safari-specific issue, not a uBOL issue.

If you encounter the issue, the current workaround is to reset to default lists, than enable lists you want to enable one by one, waiting for conversion completion between each activation, and pick the ones you really want to have first -- users will have to live with the limitations until Safari's DNR implementation gets better.

[mycodedoesnotcompile2]

Thanks @gorhill

FYI I managed to reach 27102 rules on another device with a previous version of uBOL.

[stephenhawk8054]

The number of rules counted by uBOL doesn't matter on Safari, because Safari converts to their own content blocker API rules at the end. The limitation depends totally on their final rules after converting, and uBOL can't know how that process ends up at each version.

The number of rules only matter on chromium and Firefox because they don't convert to anything weird else.

[mikhail-kirillov]

I was able to "solve" the problem: first I turned off uBlock filters — Ads, trackers, and more, and then turned on all the other filters, including the language ones. The only thing is that uBlock filters — Ads, trackers, and more cannot be turned on again. I assume the problem is duplicate ID rules in that list, which Safari cannot correctly convert to its declarativeNetRequest ruleset format

[gorhill]

I assume

Please don't assume, this just adds noise to the thread. The scope of rule ids apply only to their containing ruleset, it's perfectly fine to reuse rule ids in different rulesets. I can't keep repeating over and over that all works fine in other browsers.

[gorhill]

The only source code location I can match to this unspecific error message is at https://github.com/WebKit/WebKit/blob/6ca49cba9e21da459dd774ed4ec17603f1f56eba/Source/WebKit/UIProcess/Extensions/Cocoa/API/WebExtensionContextAPIDeclarativeNetRequestCocoa.mm#L149.

There it appears the error comes from calling loadDeclarativeNetRequestRules method, which is defined at https://github.com/WebKit/WebKit/blob/10f46a26ae45070f312c1a1e38019e131448e048/Source/WebKit/UIProcess/Extensions/Cocoa/WebExtensionContextCocoa.mm#L3209. From there, I can't tell where is the failure.

I see calls to RELEASE_LOG_ERROR() in that method, but I do not know where to look for to find the output for RELEASE_LOG_ERROR().