Changeset 271367 in webkit

Timestamp:

Jan 11, 2021, 10:12:19 AM (6 years ago)

Author:

Antti Koivisto

Message:

REGRESSION (r258321): CSS rules using :first-of-type are applied to any/all siblings in a group under certain circumstances
​https://bugs.webkit.org/show_bug.cgi?id=218256
<rdar://problem/70749584>

Reviewed by Simon Fraser.

Source/WebCore:

More accurate invalidation for :hover resulted in smaller style updates that revealed a bug in the way we
mark style non-shareable. We reset style relation bits when resolving the parent but may fail to set them again if we
don't re-resolve all children.

Test case by Eben Packwood.

Test: fast/css/positional-selector-style-sharing.html

• style/StyleRelations.cpp:

(WebCore::Style::commitRelationsToRenderStyle):

Just mark all styles affected by relations non-shareable. This is achieved via various bit tests but there
is no reason not to set the simplest no-sharing bit. Since this forces real style resolution the parent
bits will also get properly reset.

LayoutTests:

• fast/css/positional-selector-style-sharing-expected.html: Added.
• fast/css/positional-selector-style-sharing.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/css/positional-selector-style-sharing-expected.html (added)
• LayoutTests/fast/css/positional-selector-style-sharing.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/style/StyleRelations.cpp (modified) (2 diffs)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2021-01-11  Antti Koivisto  <antti@apple.com>
+
+        REGRESSION (r258321): CSS rules using :first-of-type are applied to any/all siblings in a group under certain circumstances
+        https://bugs.webkit.org/show_bug.cgi?id=218256
+        <rdar://problem/70749584>
+
+        Reviewed by Simon Fraser.
+
+        * fast/css/positional-selector-style-sharing-expected.html: Added.
+        * fast/css/positional-selector-style-sharing.html: Added.
+
 2021-01-11  Sam Weinig  <weinig@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2021-01-11  Antti Koivisto  <antti@apple.com>
+
+        REGRESSION (r258321): CSS rules using :first-of-type are applied to any/all siblings in a group under certain circumstances
+        https://bugs.webkit.org/show_bug.cgi?id=218256
+        <rdar://problem/70749584>
+
+        Reviewed by Simon Fraser.
+
+        More accurate invalidation for :hover resulted in smaller style updates that revealed a bug in the way we
+        mark style non-shareable. We reset style relation bits when resolving the parent but may fail to set them again if we
+        don't re-resolve all children.
+
+        Test case by Eben Packwood.
+
+        Test: fast/css/positional-selector-style-sharing.html
+
+        * style/StyleRelations.cpp:
+        (WebCore::Style::commitRelationsToRenderStyle):
+
+        Just mark all styles affected by relations non-shareable. This is achieved via various bit tests but there
+        is no reason not to set the simplest no-sharing bit. Since this forces real style resolution the parent
+        bits will also get properly reset.
+
 2021-01-11  Antti Koivisto  <antti@apple.com>
 

trunk/Source/WebCore/style/StyleRelations.cpp

@@ -37 +37 @@
 std::unique_ptr<Relations> commitRelationsToRenderStyle(RenderStyle& style, const Element& element, const Relations& relations)
 {
+    if (!relations.isEmpty())
+        style.setUnique();
+
     std::unique_ptr<Relations> remainingRelations;
 
@@ -62 +65 @@
             break;
         case Relation::Unique:
-            style.setUnique();
             break;
         case Relation::AffectedByPreviousSibling: