Bug 296191 – REGRESSION (iOS 26): Chromium ContentRuleList compilation frequently fails

• Status: RESOLVED
• Resolution: DUPLICATE
• Component: WebKit Misc.

[Ron Sailer]

Hi,

We're seeing increased rule list compilation failures reported from Chrome browsers running on iOS 26 for hardcoded content rule lists that previously didn't fail.

They're failing with the following error, which doesn't provide us a lot of info:

Error Domain=WKErrorDomain Code=6 "(null)" UserInfo={NSHelpAnchor=Rule list compilation failed: Unspecified error during compile.}

The list in question is: https://source.chromium.org/chromium/chromium/src/+/main:ios/web/web_state/ui/wk_content_rule_list_util.mm;l=62-85

I don't know the prevalence of the operating systems, so I don't know the failure *rate*, however speaking in absolute numbers, 94% of our failures are from devices reporting iOS 26, leading us to believe this is a recent change.

We were unable to reproduce the issue.

[Radar WebKit Bug Importer]

<rdar://problem/156150166>

[Chris Dumez]

*** This bug has been marked as a duplicate of bug 296313 ***

[Ron Sailer]

Thanks Chris for the quick response. Hopefully this fixes it.

Could you tell us when the fix will roll out?

We're still seeing elevated failures in beta 4 compared to stable OS versions, however lower than in previous betas.
At the moment I would attribute the decrease in beta 4 to a smaller user base compared to the other betas.

Thanks