Bug 241433 - Make CSS custom properties that are invalid at computed value time guaranteed-invalid
Summary: Make CSS custom properties that are invalid at computed value time guaranteed...
Status: RESOLVED CONFIGURATION CHANGED
Alias: None
Product: WebKit
Classification: Unclassified
Component: CSS (show other bugs)
Version: Safari 15
Hardware: All All
: P2 Normal
Assignee: Nobody
URL:
Keywords: BrowserCompat, InRadar
Depends on:
Blocks:
 
Reported: 2022-06-08 13:30 PDT by Shaw Jia
Modified: 2023-02-15 09:05 PST (History)
9 users (show)

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Description Shaw Jia 2022-06-08 13:30:19 PDT 
Same as this Firefox bug: https://phabricator.services.mozilla.com/D116460

Also codepen demo: https://codepen.io/Miragecraft/pen/XWaLxNb

In short, when assigning an invalid CSS custom property to another custom property, it makes the final value unset (which means "inherit" for custom properties) instead of initial.
Comment 1 Bruno Stasse 2022-06-09 05:35:08 PDT 
WebKit's behaviour now differs from both Gecko's and Blink's, causing an interoperability issue.
Comment 2 Radar WebKit Bug Importer 2022-06-15 13:31:13 PDT 
<rdar://problem/95234259>
Comment 3 Philip Jägenstedt 2022-11-10 03:08:51 PST 
Here's the relevant spec change:
https://github.com/w3c/csswg-drafts/issues/5370
https://github.com/w3c/csswg-drafts/pull/6006

And Safari-only failures in WPT:
https://wpt.fyi/results/css/css-variables/variables-substitute-guaranteed-invalid.html?run_id=6317090990981120&run_id=5097315145089024&run_id=5104235344035840&run_id=5084375415259136

The reason I noticed is because this issue was specifically called out in a freeform text comment from State of CSS 2022.
Comment 4 Antti Koivisto 2023-02-15 09:02:11 PST 
Is now working.
Comment 5 Antti Koivisto 2023-02-15 09:05:05 PST 
That is css/css-variables/variables-substitute-guaranteed-invalid.html WPT is passing.