REGRESSION(264990@main) some occlusion regions are incorrect

https://bugs.webkit.org/show_bug.cgi?id=259402 <rdar://112668310> Reviewed by Tim Horton. We already only looked at ancestors with the same absolute content box during the `position: fixed` search. But we also need to make sure we won't occlude siblings. * Source/WebCore/page/InteractionRegion.cpp: (WebCore::isOverlay): Update the overlay detection logic. * LayoutTests/interaction-region/overlay-expected.txt: * LayoutTests/interaction-region/overlay.html: Add a test covering the change. Canonical link: https://commits.webkit.org/266227@main
WebKit · Jul 22, 2023 · c73297d · c73297d
1 parent cb0fa67
commit c73297d
Show file tree

Hide file tree

Showing 3 changed files with 37 additions and 3 deletions.
diff --git a/LayoutTests/interaction-region/overlay-expected.txt b/LayoutTests/interaction-region/overlay-expected.txt
@@ -16,13 +16,14 @@
         (occlusion (0,200) width=200 height=100)
         (borderRadius 0.00)])
       )
-      (children 2
+      (children 3
         (GraphicsLayer
           (position 0.00 400.00)
           (preserves3D 1)
           (children 1
             (GraphicsLayer
               (bounds 200.00 200.00)
+              (contentsOpaque 1)
               (drawsContent 1)
               (event region
                 (rect (0,0) width=200 height=200)
@@ -34,6 +35,20 @@
             )
           )
         )
+        (GraphicsLayer
+          (position 600.00 400.00)
+          (preserves3D 1)
+          (children 1
+            (GraphicsLayer
+              (bounds 200.00 200.00)
+              (contentsOpaque 1)
+              (drawsContent 1)
+              (event region
+                (rect (0,0) width=200 height=200)
+              )
+            )
+          )
+        )
         (GraphicsLayer
           (position 600.00 0.00)
           (preserves3D 1)

diff --git a/LayoutTests/interaction-region/overlay.html b/LayoutTests/interaction-region/overlay.html
@@ -13,18 +13,26 @@
         pointer-events: none;
         background-color: red;
     }
-    #fixed-container {
+    .fixed-container {
         position: fixed;
+        width: 200px;
+        height: 200px;
         left: 0;
         bottom: 0;
         pointer-events: none;
     }
+    .fixed-container.no-occlusion {
+        left: unset;
+        right: 0;
+    }
     #fixed {
         position: fixed;
         right: 0;
         top: 0;
     }
     .paints {
+        position: absolute;
+        top: 0;
         width: 200px;
         height: 200px;
         background: blue;
@@ -40,12 +48,18 @@
 <div class="overlay"></div>
 <div class="overlay" id="not-occlusion"></div>
 <div class="overlay" onclick="click()"></div>
-<div id="fixed-container">
+<div class="fixed-container">
     <div class="paints">
         <div class="child"></div>
         <div class="child"></div>
     </div>
 </div>
+<div class="fixed-container no-occlusion">
+    <div class="child"></div>
+    <div class="paints">
+        <div class="child"></div>
+    </div>
+</div>
 <div id="fixed" class="paints"></div>
 
 <pre id="results"></pre>

diff --git a/Source/WebCore/page/InteractionRegion.cpp b/Source/WebCore/page/InteractionRegion.cpp
@@ -173,7 +173,12 @@ static bool isOverlay(const RenderElement& renderer)
 
     if (auto* renderBox = dynamicDowncast<RenderBox>(renderer)) {
         auto refContentBox = renderBox->absoluteContentBox();
+        auto lastRenderer = renderBox;
         for (auto& ancestor : ancestorsOfType<RenderBox>(renderer)) {
+            // We don't want to occlude any previous siblings.
+            if (ancestor.firstChildBox() != lastRenderer)
+                return false;
+            lastRenderer = &ancestor;
             if (ancestor.absoluteContentBox() != refContentBox)
                 return false;
             if (ancestor.isFixedPositioned())