macOS debug bots are frequently seeing the assertion below with plugins/quicktime-plugin-replacement.html: ASSERTION FAILED: willBeComposited == needsToBeComposited(layer, queryData) ./rendering/RenderLayerCompositor.cpp(1125) : void WebCore::RenderLayerCompositor::computeCompositingRequirements(WebCore::RenderLayer *, WebCore::RenderLayer &, WebCore::LayerOverlapMap &, WebCore::RenderLayerCompositor::CompositingState &, WebCore::RenderLayerCompositor::BackingSharingState &, bool &) 1 0x2387b5f29 WTFCrash 2 0x2180032eb WTFCrashWithInfo(int, char const*, char const*, int) 3 0x21c8627dc WebCore::RenderLayerCompositor::computeCompositingRequirements(WebCore::RenderLayer*, WebCore::RenderLayer&, WebCore::LayerOverlapMap&, WebCore::RenderLayerCompositor::CompositingState&, WebCore::RenderLayerCompositor::BackingSharingState&, bool&) 4 0x21c8623e7 WebCore::RenderLayerCompositor::computeCompositingRequirements(WebCore::RenderLayer*, WebCore::RenderLayer&, WebCore::LayerOverlapMap&, WebCore::RenderLayerCompositor::CompositingState&, WebCore::RenderLayerCompositor::BackingSharingState&, bool&) 5 0x21c86249a WebCore::RenderLayerCompositor::computeCompositingRequirements(WebCore::RenderLayer*, WebCore::RenderLayer&, WebCore::LayerOverlapMap&, WebCore::RenderLayerCompositor::CompositingState&, WebCore::RenderLayerCompositor::BackingSharingState&, bool&) 6 0x21c82cb8e WebCore::RenderLayerCompositor::updateCompositingLayers(WebCore::CompositingUpdateType, WebCore::RenderLayer*) 7 0x21c85ef9e WebCore::RenderLayerCompositor::updateCompositingLayersTimerFired() 8 0x21c89bb57 decltype(*(std::__1::forward<WebCore::RenderLayerCompositor*&>(fp0)).*fp()) std::__1::__invoke<void (WebCore::RenderLayerCompositor::*&)(), WebCore::RenderLayerCompositor*&, void>(void (WebCore::RenderLayerCompositor::*&)(), WebCore::RenderLayerCompositor*&) 9 0x21c89bad0 std::__1::__bind_return<void (WebCore::RenderLayerCompositor::*)(), std::__1::tuple<WebCore::RenderLayerCompositor*>, std::__1::tuple<>, __is_valid_bind_return<void (WebCore::RenderLayerCompositor::*)(), std::__1::tuple<WebCore::RenderLayerCompositor*>, std::__1::tuple<> >::value>::type std::__1::__apply_functor<void (WebCore::RenderLayerCompositor::*)(), std::__1::tuple<WebCore::RenderLayerCompositor*>, 0ul, std::__1::tuple<> >(void (WebCore::RenderLayerCompositor::*&)(), std::__1::tuple<WebCore::RenderLayerCompositor*>&, std::__1::__tuple_indices<0ul>, std::__1::tuple<>&&) 10 0x21c89ba89 std::__1::__bind_return<void (WebCore::RenderLayerCompositor::*)(), std::__1::tuple<WebCore::RenderLayerCompositor*>, std::__1::tuple<>, __is_valid_bind_return<void (WebCore::RenderLayerCompositor::*)(), std::__1::tuple<WebCore::RenderLayerCompositor*>, std::__1::tuple<> >::value>::type std::__1::__bind<void (WebCore::RenderLayerCompositor::*&)(), WebCore::RenderLayerCompositor*>::operator()<>() 11 0x21c89ba2e WTF::Detail::CallableWrapper<std::__1::__bind<void (WebCore::RenderLayerCompositor::*&)(), WebCore::RenderLayerCompositor*>, void>::call() 12 0x218017642 WTF::Function<void ()>::operator()() const 13 0x21804eb1e WebCore::Timer::fired() 14 0x21c089dd4 WebCore::ThreadTimers::sharedTimerFiredInternal() 15 0x21c0930b1 WebCore::ThreadTimers::setSharedTimer(WebCore::SharedTimer*)::$_0::operator()() const 16 0x21c09305e WTF::Detail::CallableWrapper<WebCore::ThreadTimers::setSharedTimer(WebCore::SharedTimer*)::$_0, void>::call() 17 0x218017642 WTF::Function<void ()>::operator()() const 18 0x21c0463db WebCore::MainThreadSharedTimer::fired() 19 0x21c101ee6 WebCore::timerFired(__CFRunLoopTimer*, void*) 20 0x7fff350507f9 __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__ 21 0x7fff3505035f __CFRunLoopDoTimer 22 0x7fff3504fe47 __CFRunLoopDoTimers 23 0x7fff35034bea __CFRunLoopRun 24 0x7fff35033e3e CFRunLoopRunSpecific 25 0x7fff376cf1c8 -[NSRunLoop(NSRunLoop) runMode:beforeDate:] 26 0x7fff37781c6f -[NSRunLoop(NSRunLoop) run] 27 0x7fff6f2ee4ea _xpc_objc_main.cold.4 28 0x7fff6f2ee430 _xpc_objc_main 29 0x7fff6f2edf63 _xpc_copy_xpcservice_dictionary 30 0x1032fcafc WebKit::XPCServiceMain(int, char const**) 31 0x1046c2b8b WKXPCServiceMain LEAK: 2 WebPageProxy https://results.webkit.org/?suite=layout-tests&test=plugins%2Fquicktime-plugin-replacement.html
<rdar://problem/71208603>
Created attachment 413628 [details] crash log
This appears to have started with https://trac.webkit.org/changeset/269407/webkit I can reproduce the crash with a local debug build by simply running plugins/quicktime-plugin-replacement.html. It does not reproduce with r269405.
Created attachment 413716 [details] Patch
Committed r269637: <https://trac.webkit.org/changeset/269637> All reviewed patches have been landed. Closing bug and clearing flags on attachment 413716 [details].