Seeing the flaky assert below on iOS simulator debug bots with the following layout tests fast/events/tabindex-focus-blur-all.html media/media-blocked-by-willsendrequest.html media/modern-media-controls/mute-button/mute-button.html ASSERTION FAILED: !m_messageReceiverMapCount /Volumes/Data/worker/ios-simulator-14-debug/build/Source/WebKit/Platform/IPC/MessageReceiver.h(41) : virtual IPC::MessageReceiver::~MessageReceiver() 1 0x173a7ed99 WTFCrash 2 0x1580b131b WTFCrashWithInfo(int, char const*, char const*, int) 3 0x1580f5818 IPC::MessageReceiver::~MessageReceiver() 4 0x159d4deff WebKit::RemoteRemoteCommandListener::~RemoteRemoteCommandListener() 5 0x159d4e015 WebKit::RemoteRemoteCommandListener::~RemoteRemoteCommandListener() 6 0x159d4e07c WebKit::RemoteRemoteCommandListener::~RemoteRemoteCommandListener() 7 0x18019dc4f std::__1::default_delete<WebCore::RemoteCommandListener>::operator()(WebCore::RemoteCommandListener*) const 8 0x18019dbcf std::__1::unique_ptr<WebCore::RemoteCommandListener, std::__1::default_delete<WebCore::RemoteCommandListener> >::reset(WebCore::RemoteCommandListener*) 9 0x1801926a7 std::__1::unique_ptr<WebCore::RemoteCommandListener, std::__1::default_delete<WebCore::RemoteCommandListener> >::operator=(std::nullptr_t) 10 0x180192519 WebCore::NowPlayingManager::removeClient(WebCore::NowPlayingManager::Client&) 11 0x17db86ba8 WebCore::MediaSessionManagerCocoa::removeSession(WebCore::PlatformMediaSession&) 12 0x180220ecc WebCore::PlatformMediaSession::stopSession() 13 0x17f5a877c WebCore::HTMLMediaElement::stop() 14 0x17f212ebd auto WebCore::ScriptExecutionContext::stopActiveDOMObjects()::$_3::operator()<WebCore::ActiveDOMObject>(WebCore::ActiveDOMObject&) const 15 0x17f212e53 WTF::Detail::CallableWrapper<WebCore::ScriptExecutionContext::stopActiveDOMObjects()::$_3, WebCore::ScriptExecutionContext::ShouldContinue, WebCore::ActiveDOMObject&>::call(WebCore::ActiveDOMObject&) 16 0x17f1fb93a WTF::Function<WebCore::ScriptExecutionContext::ShouldContinue (WebCore::ActiveDOMObject&)>::operator()(WebCore::ActiveDOMObject&) const 17 0x17f1fb790 WebCore::ScriptExecutionContext::forEachActiveDOMObject(WTF::Function<WebCore::ScriptExecutionContext::ShouldContinue (WebCore::ActiveDOMObject&)> const&) const 18 0x17f1fbca7 WebCore::ScriptExecutionContext::stopActiveDOMObjects() 19 0x17efba2ef WebCore::Document::stopActiveDOMObjects() 20 0x17efba08c WebCore::Document::commonTeardown() 21 0x17efc732b WebCore::Document::willBeRemovedFromFrame() 22 0x17ff289b3 WebCore::Frame::setView(WTF::RefPtr<WebCore::FrameView, WTF::RawPtrTraits<WebCore::FrameView>, WTF::DefaultRefDerefTraits<WebCore::FrameView> >&&) 23 0x17fcf409e WebCore::FrameLoader::closeAndRemoveChild(WebCore::Frame&) 24 0x17fcf3fa3 WebCore::FrameLoader::detachFromParent() 25 0x17fce6f4a WebCore::FrameLoader::detachChildren() 26 0x17fcf3f0c WebCore::FrameLoader::detachFromParent() 27 0x17fcf473d WebCore::FrameLoader::frameDetached() 28 0x17f546099 WebCore::HTMLFrameOwnerElement::disconnectContentFrame() 29 0x17ef725f1 WebCore::disconnectSubframes(WebCore::ContainerNode&, WebCore::SubframeDisconnectPolicy) 30 0x17ef50ba5 WebCore::disconnectSubframesIfNeeded(WebCore::ContainerNode&, WebCore::SubframeDisconnectPolicy) 31 0x17ef4d64d WebCore::ContainerNode::removeAllChildrenWithScriptAssertion(WebCore::ContainerNode::ChildChange::Source, WebCore::ContainerNode::DeferChildrenChanged) com.apple.WebKit.WebContent.Development terminated (pid 34892) because the process crashed https://results.webkit.org/?suite=layout-tests&suite=layout-tests&suite=layout-tests&test=fast%2Fevents%2Ftabindex-focus-blur-all.html&test=media%2Fmedia-blocked-by-willsendrequest.html&test=media%2Fmodern-media-controls%2Fmute-button%2Fmute-button.html
<rdar://problem/78481758>
Maybe related to "[Cocoa] Enable MediaSession and MediaSessionCoordinator experimental features " https://trac.webkit.org/changeset/276338/webkit?
(In reply to Ryan Haddad from comment #2) > Maybe related to "[Cocoa] Enable MediaSession and MediaSessionCoordinator > experimental features > " https://trac.webkit.org/changeset/276338/webkit? No, RemoteRemoteCommandListener is used to hook up to NowPlaying.
Created attachment 432915 [details] Patch
Committed r279584 (239415@main): <https://commits.webkit.org/239415@main> All reviewed patches have been landed. Closing bug and clearing flags on attachment 432915 [details].