[webkit-changes] [WebKit/WebKit] e0fa0f: REGRESSION (258514 at main): Transition of !important...

[Antti Koivisto]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: e0fa0f2073f1886a7272a69040adaaafde9754fd
      https://github.com/WebKit/WebKit/commit/e0fa0f2073f1886a7272a69040adaaafde9754fd
  Author: Antti Koivisto <antti at apple.com>
  Date:   2023-02-27 (Mon, 27 Feb 2023)

  Changed paths:
    A LayoutTests/imported/w3c/web-platform-tests/css/css-transitions/transition-important-expected.txt
    A LayoutTests/imported/w3c/web-platform-tests/css/css-transitions/transition-important.html
    M Source/WebCore/style/PropertyCascade.cpp
    M Source/WebCore/style/PropertyCascade.h
    M Source/WebCore/style/StyleTreeResolver.cpp
    M Source/WebCore/style/StyleTreeResolver.h

  Log Message:
  -----------
  REGRESSION (258514 at main): Transition of !important property fails to animate
https://bugs.webkit.org/show_bug.cgi?id=111329
rdar://105929421

Reviewed by Antoine Quint.

The cascade precedence is (https://drafts.csswg.org/css-cascade-5/#cascade-sort)

1) Transition declarations [css-transitions-1]
2) Important user agent declarations
3) Important user declarations
4) Important author declarations
5) Animation declarations [css-animations-1]
6) Normal author declarations
7) Normal user declarations
8) Normal user agent declarations

but we were treating transitions and animations similarly.

* LayoutTests/imported/w3c/web-platform-tests/css/css-transitions/transition-important-expected.txt: Added.
* LayoutTests/imported/w3c/web-platform-tests/css/css-transitions/transition-important.html: Added.
* Source/WebCore/style/PropertyCascade.cpp:
(WebCore::Style::PropertyCascade::addMatch):
(WebCore::Style::PropertyCascade::shouldApplyAfterAnimation):

Don't let !important properties override transitions.

* Source/WebCore/style/PropertyCascade.h:
* Source/WebCore/style/StyleTreeResolver.cpp:
(WebCore::Style::TreeResolver::createAnimatedElementUpdate):

Tell the cascade if this is a transition or animation.
Note that this is still incorrect in the (rare) case where you would have both running on an element at the same time.

(WebCore::Style::TreeResolver::applyCascadeAfterAnimation):
* Source/WebCore/style/StyleTreeResolver.h:

Canonical link: https://commits.webkit.org/260880@main