Branch: refs/heads/main
Home: https://github.com/WebKit/WebKit
Commit: d390890aae723e08d30bff8afbf72785e7cbaa87
https://github.com/WebKit/WebKit/commit/d390890aae723e08d30bff8afbf72785e7cbaa87
Author: Simon Fraser <[email protected]>
Date: 2026-03-28 (Sat, 28 Mar 2026)
Changed paths:
R
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt
R
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero.html
A
LayoutTests/fast/scrolling/ios/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt
A
LayoutTests/fast/scrolling/ios/cancel-animated-scroll-should-not-scroll-from-zero.html
A
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-main-frame-expected.txt
A
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-main-frame.html
A
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-overflow-expected.txt
A
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-overflow.html
A LayoutTests/fast/scrolling/ios/smooth-scroll-animates-expected.txt
A LayoutTests/fast/scrolling/ios/smooth-scroll-animates.html
A
LayoutTests/fast/scrolling/mac/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt
A
LayoutTests/fast/scrolling/mac/cancel-animated-scroll-should-not-scroll-from-zero.html
A
LayoutTests/fast/scrolling/programmatic-smooth-then-immediate-cancels-animation-expected.txt
A
LayoutTests/fast/scrolling/programmatic-smooth-then-immediate-cancels-animation.html
M Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.cpp
M Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.h
M Source/WebCore/page/scrolling/ScrollingTreeScrollingNodeDelegate.h
M
Source/WebCore/page/scrolling/ThreadedScrollingTreeScrollingNodeDelegate.cpp
M Source/WebCore/page/scrolling/ThreadedScrollingTreeScrollingNodeDelegate.h
M Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm
M
Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp
M
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h
M
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm
Log Message:
-----------
Cannot set scrollTop during momentum scroll phase
https://bugs.webkit.org/show_bug.cgi?id=187449
rdar://41949531
Reviewed by Abrar Rahman Protyasha.
Historically, `scrollTo` has interrupted momentum scrolling on iOS, but not
macOS. Interactions
between programmatic and user scrolling are not specified, but it's a better
user experience if
momentum scrolls continue when content calls `scrollTo` (some virtual scrollers
required it for
good behavior).
This change fixes that. For iOS main frame,
`RemoteScrollingCoordinatorProxy::adjustMainFrameDelegatedScrollPosition()`
now simply passes `InterruptScrollAnimation::No`. For subscrollers, the change
in
`ScrollingTreeScrollingNode::handleScrollPositionRequest()` ensures that only
programmatic
scrolls are interrupted, but we have to do some plumbing of
`AnimatedScrollType` so that
`ScrollingTreeScrollingNodeDelegateIOS::stopAnimatedScroll()` knows which
scroll types to
interrupt (it's unique to iOS that an "animated scroll" on the UIScrollView can
be either
started by the user, or by a programmatic scroll).
During this investigation, I discovered that smooth scrolls on the root were no
longer smooth on iOS;
the change in `_scrollToContentScrollPosition:` fixes this, and
`smooth-scroll-animates.html`
tests it.
The `cancel-animated-scroll-should-not-scroll-from-zero.html` test was forked
for iOS;
it used the wheel event monitor machinery, which only works on macOS.
Tests:
fast/scrolling/ios/cancel-animated-scroll-should-not-scroll-from-zero.html
fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-main-frame.html
fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-overflow.html
fast/scrolling/ios/smooth-scroll-animates.html
fast/scrolling/mac/cancel-animated-scroll-should-not-scroll-from-zero.html
fast/scrolling/programmatic-smooth-then-immediate-cancels-animation.html
*
LayoutTests/fast/scrolling/ios/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt:
Copied from
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt.
*
LayoutTests/fast/scrolling/ios/cancel-animated-scroll-should-not-scroll-from-zero.html:
Copied from
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero.html.
*
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-main-frame-expected.txt:
Added.
*
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-main-frame.html:
Added.
*
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-overflow-expected.txt:
Added.
*
LayoutTests/fast/scrolling/ios/scrollto-does-not-interrupt-momentum-scroll-overflow.html:
Added.
* LayoutTests/fast/scrolling/ios/smooth-scroll-animates-expected.txt: Added.
* LayoutTests/fast/scrolling/ios/smooth-scroll-animates.html: Added.
*
LayoutTests/fast/scrolling/mac/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt:
Renamed from
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero-expected.txt.
*
LayoutTests/fast/scrolling/mac/cancel-animated-scroll-should-not-scroll-from-zero.html:
Renamed from
LayoutTests/fast/scrolling/cancel-animated-scroll-should-not-scroll-from-zero.html.
*
LayoutTests/fast/scrolling/programmatic-smooth-then-immediate-cancels-animation-expected.txt:
Added.
*
LayoutTests/fast/scrolling/programmatic-smooth-then-immediate-cancels-animation.html:
Added.
* Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.cpp:
(WebCore::ScrollingTreeScrollingNode::stopAnimatedScroll):
(WebCore::ScrollingTreeScrollingNode::handleScrollPositionRequest):
* Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.h:
* Source/WebCore/page/scrolling/ScrollingTreeScrollingNodeDelegate.h:
* Source/WebCore/page/scrolling/ThreadedScrollingTreeScrollingNodeDelegate.cpp:
(WebCore::ThreadedScrollingTreeScrollingNodeDelegate::stopAnimatedScroll):
* Source/WebCore/page/scrolling/ThreadedScrollingTreeScrollingNodeDelegate.h:
* Source/WebKit/UIProcess/API/ios/WKWebViewIOS.mm:
(-[WKWebView
_scrollToContentScrollPosition:scrollOrigin:animated:interruptAnimation:]):
* Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp:
(WebKit::RemoteScrollingCoordinatorProxy::adjustMainFrameDelegatedScrollPosition):
*
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.h:
*
Source/WebKit/UIProcess/RemoteLayerTree/ios/ScrollingTreeScrollingNodeDelegateIOS.mm:
(WebKit::ScrollingTreeScrollingNodeDelegateIOS::stopAnimatedScroll):
Canonical link: https://commits.webkit.org/310169@main
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