Created attachment 401466 [details] crash log media/video-autoplay.html is frequently failing the assertion below on iOS Debug testers: ASSERTION FAILED: m_clientCounts.contains(contextId) /Volumes/Data/slave/ios-simulator-13-debug/build/Source/WebKit/UIProcess/Cocoa/VideoFullscreenManagerProxy.mm(462) : void WebKit::VideoFullscreenManagerProxy::removeClientForContext(uint64_t) 1 0x10bfdf5a9 WTFCrash 2 0x11616a23b WTFCrashWithInfo(int, char const*, char const*, int) 3 0x116de171c WebKit::VideoFullscreenManagerProxy::removeClientForContext(unsigned long long) 4 0x116dde1d6 WebKit::VideoFullscreenManagerProxy::didCleanupFullscreen(unsigned long long) 5 0x116dde090 WebKit::VideoFullscreenModelContext::didCleanupFullscreen() 6 0x12ae25934 WebCore::VideoFullscreenInterfaceAVKit::cleanupFullscreen() 7 0x116de3ab1 WebKit::VideoFullscreenManagerProxy::cleanupFullscreen(unsigned long long) 8 0x117846890 void IPC::callMemberFunctionImpl<WebKit::VideoFullscreenManagerProxy, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long), std::__1::tuple<unsigned long long>, 0ul>(WebKit::VideoFullscreenManagerProxy*, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long), std::__1::tuple<unsigned long long>&&, std::__1::integer_sequence<unsigned long, 0ul>) 9 0x1178467d0 void IPC::callMemberFunction<WebKit::VideoFullscreenManagerProxy, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long), std::__1::tuple<unsigned long long>, std::__1::integer_sequence<unsigned long, 0ul> >(std::__1::tuple<unsigned long long>&&, WebKit::VideoFullscreenManagerProxy*, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long)) 10 0x117841be6 void IPC::handleMessage<Messages::VideoFullscreenManagerProxy::CleanupFullscreen, WebKit::VideoFullscreenManagerProxy, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long)>(IPC::Decoder&, WebKit::VideoFullscreenManagerProxy*, void (WebKit::VideoFullscreenManagerProxy::*)(unsigned long long)) 11 0x117841510 WebKit::VideoFullscreenManagerProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) 12 0x11627e361 IPC::MessageReceiverMap::dispatchMessage(IPC::Connection&, IPC::Decoder&) 13 0x116dc280e WebKit::AuxiliaryProcessProxy::dispatchMessage(IPC::Connection&, IPC::Decoder&) 14 0x116fbe4cf WebKit::WebProcessProxy::didReceiveMessage(IPC::Connection&, IPC::Decoder&) 15 0x1161dc99f IPC::Connection::dispatchMessage(IPC::Decoder&) 16 0x1161dd2d0 IPC::Connection::dispatchMessage(std::__1::unique_ptr<IPC::Decoder, std::__1::default_delete<IPC::Decoder> >) 17 0x1161dbbe1 IPC::Connection::dispatchIncomingMessages() 18 0x1161ff05f IPC::Connection::MessagesThrottler::scheduleMessagesDispatch()::$_10::operator()() 19 0x1161fef3e WTF::Detail::CallableWrapper<IPC::Connection::MessagesThrottler::scheduleMessagesDispatch()::$_10, void>::call() 20 0x10c00aca2 WTF::Function<void ()>::operator()() const 21 0x10c0841c8 WTF::RunLoop::performWork() 22 0x10c085971 WTF::RunLoop::performWork(void*) 23 0x112fb8c71 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ 24 0x112fb8b9c __CFRunLoopDoSource0 25 0x112fb8374 __CFRunLoopDoSources0 26 0x112fb2f6e __CFRunLoopRun 27 0x112fb2884 CFRunLoopRunSpecific 28 0x11262b831 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] 29 0x10b008c2e WTR::TestController::platformRunUntil(bool&, WTF::Seconds) 30 0x10afc525f WTR::TestController::runUntil(bool&, WTF::Seconds) 31 0x10b00ec5a WTR::TestInvocation::invoke() https://results.webkit.org/?suite=layout-tests&test=media%2Fvideo-autoplay.html https://build.webkit.org/results/Apple%20iOS%2013%20Simulator%20Debug%20WK2%20(Tests)/r262796%20(4090)/results.html
<rdar://problem/64176481>
This regressed on or around 5/1/2020. https://trac.webkit.org/changeset/261001/webkit seems to be the most likely candidate.
Created attachment 403620 [details] Patch
Committed r263991: <https://trac.webkit.org/changeset/263991> All reviewed patches have been landed. Closing bug and clearing flags on attachment 403620 [details].