Recalculate intrinsic widths in the old containing block chain when g…

…oing out of flow Recalculate intrinsic widths in the old containing block chain when going out of flow https://bugs.webkit.org/show_bug.cgi?id=249259 Reviewed by Alan Baradlay. This patch is to align Webkit with Blink / Chromium and Gecko / Firefox. Merge - https://src.chromium.org/viewvc/blink?revision=200836&view=revision When an object goes out of flow, it no longer contributes to the intrinisic widths of its parents. We need to mark them for recalculation while we can still walk that ancestry chain, i.e. before applying the style change. * Source/WebCore/rendering/RenderBox.cpp: (RenderBox::styleWillChange): Add logic for recalculation * LayoutTests/fast/block/positioning/static-to-abpos-parent-is-stf.html: Add Test Case * LayoutTests/fast/block/positioning/static-to-abpos-parent-is-stf-expected.html: Add Test Case Expectation Canonical link: https://commits.webkit.org/257980@main
WebKit · Dec 16, 2022 · ca04468e9d7160d8fbc0d50879d984d2052abd02 · ca04468
1 parent 2a8263e
commit ca04468e9d7160d8fbc0d50879d984d2052abd02
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diff --git a/LayoutTests/fast/block/positioning/static-to-abspos-parent-is-stf-expected.txt b/LayoutTests/fast/block/positioning/static-to-abspos-parent-is-stf-expected.txt
@@ -0,0 +1,5 @@
+Change from position:static to position:absolute when the parent is a shrink-to-fit container. The parent needs to recalculate its intrinsic size when this happens.
+
+There should be a black square below.
+
+PASS
diff --git a/LayoutTests/fast/block/positioning/static-to-abspos-parent-is-stf.html b/LayoutTests/fast/block/positioning/static-to-abspos-parent-is-stf.html
@@ -0,0 +1,15 @@
+<!DOCTYPE html>
+<script src="../../../resources/check-layout.js"></script>
+<p>Change from position:static to position:absolute when the parent is a shrink-to-fit container.
+    The parent needs to recalculate its intrinsic size when this happens.</p>
+<p>There should be a black <em>square</em> below.</p>
+<div id="container" style="float:left; border:20px solid black;" data-expected-width="40" data-expected-height="40">
+    <div id="test" style="width:100px; height:100px;"></div>
+</div>
+<p id="result" style="clear:both;"></p>
+<script>
+    var test = document.getElementById("test");
+    test.offsetTop;
+    test.style.position = "absolute";
+    checkLayout("#container", document.getElementById("result"));
+</script>
diff --git a/Source/WebCore/rendering/RenderBox.cpp b/Source/WebCore/rendering/RenderBox.cpp
@@ -284,7 +284,13 @@ void RenderBox::styleWillChange(StyleDifference diff, const RenderStyle& newStyl
         // When a layout hint happens and an object's position style changes, we have to do a layout
         // to dirty the render tree using the old position value now.
         if (diff == StyleDifference::Layout && parent() && oldStyle->position() != newStyle.position()) {
-            markContainingBlocksForLayout();
+            if (!oldStyle->hasOutOfFlowPosition() && newStyle.hasOutOfFlowPosition()) {
+                // We are about to go out of flow. Before that takes place, we need to mark the
+                // current containing block chain for preferred widths recalculation.
+                setNeedsLayoutAndPrefWidthsRecalc();
+            } else
+                markContainingBlocksForLayout();
+
             if (oldStyle->position() != PositionType::Static && newStyle.hasOutOfFlowPosition())
                 parent()->setChildNeedsLayout();
             if (isFloating() && !isOutOfFlowPositioned() && newStyle.hasOutOfFlowPosition())