Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: 7bdd6f4aabffd6a17c4c5663b6d4e26a90190c63
https://github.com/WebKit/WebKit/commit/7bdd6f4aabffd6a17c4c5663b6d4e26a90190c63
Author: Simon Fraser <[email protected]>
Date: 2026-02-28 (Sat, 28 Feb 2026)
Changed paths:
M
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/input/snap-area-overflow-boundary-expected.txt
A
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/resnap-on-layout-is-immediate-expected.txt
A
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/resnap-on-layout-is-immediate.html
M LayoutTests/platform/mac-wk2/TestExpectations
M Source/WebCore/platform/ScrollableArea.cpp
Log Message:
-----------
[Scroll snap] YouTube shorts scroll to the next video and back
https://bugs.webkit.org/show_bug.cgi?id=308913
rdar://166596210
Reviewed by Wenson Hsieh and Alan Baradlay.
The YouTube shorts page uses scroll snap. When the page first loads, there's a
`<div id='initial-player-container’>`
item above the first short with non-zero height, pushing the first video (which
has the first snap point) down. We
scroll down to snap to it, and then a layout changes the height of `<div
id='initial-player-container’>` to zero,
triggering a scroll back to 0. However, a message comes back from the UI
process for the first scroll, and resets
the scroll position closer to the second video, so we scroll back down (and
then the page calls `scrollIntoView()`
and the scroll position animates back up).
The bug here was that the scroll-snap related scrolls were not marked as
programmatic, so they did not cause
synchronous scroll position updates in the web process, and thus mis-handled
the messages coming back from
the UI process (logic fixed in 308215@main).
The fix uses a `ScrollTypeScope` to mark resnapping scrolls as programmatic.
Test:
imported/w3c/web-platform-tests/css/css-scroll-snap/resnap-on-layout-is-immediate.html
*
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/input/snap-area-overflow-boundary-expected.txt:
Fails
in a different way now.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/resnap-on-layout-is-immediate-expected.txt:
Added.
*
LayoutTests/imported/w3c/web-platform-tests/css/css-scroll-snap/resnap-on-layout-is-immediate.html:
Added.
* LayoutTests/platform/mac-wk2/TestExpectations: One new pass.
* Source/WebCore/platform/ScrollableArea.cpp:
(WebCore::ScrollableArea::resnapAfterLayout):
Canonical link: https://commits.webkit.org/308420@main
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