Bug 304116 – [threaded-animations] WPT test `scroll-animations/scroll-timelines/setting-timeline.tentative.html` crashes with "Threaded Time-based Animations" enabled

• Component: Animations
• Status: RESOLVED DUPLICATE

[Antoine Quint]

The following subtest yields a failed assertion:

promise_test(async t => {
  const animation = createAnimation(t);
  const scrollTimeline = createScrollTimeline(t);
  animation.timeline = scrollTimeline;
  await animation.ready;
  await updateScrollPosition(scrollTimeline, 100);

  animation.timeline = document.timeline;
  assert_times_equal(animation.currentTime, 100);
}, 'Transitioning from a scroll timeline to a document timeline on a running ' +
   'animation preserves currentTime');

Here's the last few frames in the stack trace:

#0	0x0000000304ce394c in WebCore::WebAnimationTime::operator- at /Source/WebCore/animation/WebAnimationTime.cpp:183
#1	0x0000000304ce38cc in WebCore::WebAnimation::currentTime at /Source/WebCore/animation/WebAnimation.cpp:512
#2	0x0000000304cd7240 in WebCore::WebAnimation::currentTime at /Source/WebCore/animation/WebAnimation.cpp:489
#3	0x0000000304cd56b0 in WebCore::WebAnimation::playState at /Source/WebCore/animation/WebAnimation.cpp:784
#4	0x0000000304c635c8 in WebCore::KeyframeEffect::isRunningAccelerated at /Source/WebCore/animation/KeyframeEffect.cpp:1666
#5	0x0000000304c6aaf4 in WebCore::KeyframeEffect::StackMembershipMutationScope::~StackMembershipMutationScope at /Source/WebCore/animation/KeyframeEffect.cpp:3073
#6	0x0000000304c625e0 in WebCore::KeyframeEffect::StackMembershipMutationScope::~StackMembershipMutationScope at /Source/WebCore/animation/KeyframeEffect.cpp:3065
#7	0x0000000304c62384 in WebCore::KeyframeEffect::updateEffectStackMembership at /Source/WebCore/animation/KeyframeEffect.cpp:1531
#8	0x0000000304c6226c in WebCore::KeyframeEffect::animationTimelineDidChange at /Source/WebCore/animation/KeyframeEffect.cpp:1506
#9	0x0000000304ce25d0 in WebCore::WebAnimation::setTimelineInternal at /Source/WebCore/animation/WebAnimation.cpp:384
#10	0x0000000304cd6b94 in WebCore::WebAnimation::setTimeline at /Source/WebCore/animation/WebAnimation.cpp:314
#11	0x0000000304ce2ae8 in WebCore::WebAnimation::setBindingsTimeline at /Source/WebCore/animation/WebAnimation.cpp:260

This is a common error when dealing with timeline changes with different types (progress-based v. monotonic). We need to clear cached time values at some point prior to querying the play state here.

[Radar WebKit Bug Importer]

<rdar://problem/166940957>

[Antoine Quint]

*** This bug has been marked as a duplicate of bug 306625 ***