Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 5d1f5f0b510e37294aad30942d5513c106c452fc
https://github.com/WebKit/WebKit/commit/5d1f5f0b510e37294aad30942d5513c106c452fc
Author: Alan Baradlay <[email protected]>
Date: 2026-05-05 (Tue, 05 May 2026)
Changed paths:
A LayoutTests/fast/block/block-in-inline-max-height-change-expected.html
A LayoutTests/fast/block/block-in-inline-max-height-change.html
M Source/WebCore/rendering/RenderBlockFlow.cpp
Log Message:
-----------
[block-in-inline] Container does not expand when max-height is removed
https://bugs.webkit.org/show_bug.cgi?id=314036
<rdar://175799547>
Reviewed by Antti Koivisto.
When a container with block-in-inline content (e.g. a <div> inside a <span>)
has its max-height removed via a style change, the container should re-layout
and grow to fit its content. Instead, it stayed at the old height.
The block-in-inline fast path (layoutSimpleBlockContentInInline) is designed
to skip full inline layout when only the block children need re-layout and the
inline content is unchanged. But it was incorrectly triggered here because of
how preferred-width invalidation interacted with the eligibility check.
When max-height changes, all children get their preferred widths invalidated
(needsPreferredLogicalWidthsUpdate = true) even though none need actual layout
(needsLayout = false). The walker in markInlineContentDirtyForLayout let these
renderers through its guard (which checks both needsLayout and needsPrefWidths),
and then the contentNeedsNormalChildLayoutOnly flag was set to true via
value_or(true) because !needsLayout() was trivially true. This made the fast
path think "only block content needs layout" when in reality nothing needed
layout -only the container itself did (for the max-height change).
The fix: only update contentNeedsNormalChildLayoutOnly when the renderer
actually needs layout, not when it only needs preferred width recomputation.
Note: This is a block-direction-only change on the container with no dirty
children.
It currently needs full inline layout (wasteful and unneeded) just to update
the block size -which is what the fast path skips.
Tests: fast/block/block-in-inline-max-height-change.html
* Source/WebCore/rendering/RenderBlockFlow.cpp:
(WebCore::RenderBlockFlow::markInlineContentDirtyForLayout):
Canonical link: https://commits.webkit.org/312608@main
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