313145 2026-04-23 10:07:55 -0700 REGRESSION(311815@main): [macOS Debug]: ASSERTION FAILED: !m_screenPropertiesChangedObservers.contains(observer) 2026-04-23 10:09:59 -0700 1 1 1 Unclassified WebKit New Bugs WebKit Nightly Build Unspecified Unspecified RESOLVED DUPLICATE 313144 InRadar P2 Normal --- 1 darbinyan webkit-unassigned webkit-bot-watchers-bugzilla webkit-bug-importer oldest_to_newest 2203740 0 darbinyan 2026-04-23 10:07:55 -0700 Multiple media tests are crashing in Debug after 311815@main. fast/dom/crash-moving-subtree-between-documents.html fast/events/event-handler-detached-document-dispatchEvent.html fast/media/template-hidden.html http/tests/lockdown-mode/media-element-is-suspended-crash.html http/tests/webrtc/video-mediastream-invisible-autoplay-detached.html imported/blink/fullscreen/full-screen-detached-document.html imported/blink/media/track/media-element-move-to-new-document-assert.html imported/w3c/web-platform-tests/html/semantics/embedded-content/media-elements/loading-the-media-resource/resource-selection-invoke-insert-into-iframe.html imported/w3c/web-platform-tests/html/semantics/embedded-content/media-elements/playing-the-media-resource/pause-move-to-other-document.html imported/w3c/web-platform-tests/html/semantics/embedded-content/the-audio-element/audio-appendChild-to-inactive-document-crash.html imported/w3c/web-platform-tests/html/semantics/embedded-content/the-audio-element/audio-play-in-inactive-document-crash.html imported/w3c/web-platform-tests/html/semantics/forms/the-label-element/clicking-interactive-content.html imported/w3c/web-platform-tests/html/semantics/forms/the-label-element/clicking-noninteractive-unlabelable-content.html imported/w3c/web-platform-tests/html/semantics/scripting-1/the-template-element/template-element/template-content.html imported/w3c/web-platform-tests/shadow-dom/crashtests/move-to-new-tree-1343016.html imported/w3c/web-platform-tests/shadow-dom/declarative/declarative-shadow-dom-basic.html media/adopt-node-after-showing-picker-crash.html media/adopt-node-crash.html media/audio-controls-adoptNode.html media/media-reparent.html media/track/track-remove-crash.html media/video-controls-adoptNode.html ASSERTION FAILED: !m_screenPropertiesChangedObservers.contains(observer) /Volumes/Data/worker/macOS-Tahoe-Debug-Build-EWS/build/Source/WebCore/dom/Document.cpp(8884) : void WebCore::Document::addScreenPropertiesChangedObserver(const ScreenPropertiesChangedObserver &) 1 0x305975940 WebCore::Document::addScreenPropertiesChangedObserver(WTF::Observer<void (unsigned int)> const&) 2 0x306090778 WebCore::HTMLMediaElement::registerWithDocument(WebCore::Document&) 3 0x3060938a0 WebCore::HTMLMediaElement::didMoveToNewDocument(WebCore::Document&, WebCore::Document&) 4 0x3061ac278 WebCore::HTMLVideoElement::didMoveToNewDocument(WebCore::Document&, WebCore::Document&) https://ews-build.webkit.org/#/builders/161/builds/26266 Test history: https://results.webkit.org/?suite=layout-tests&suite=layout-tests&suite=layout-tests&suite=layout-tests&suite=layout-tests&suite=layout-tests&suite=layout-tests&test=imported%2Fw3c%2Fweb-platform-tests%2Fshadow-dom%2Fdeclarative%2Fdeclarative-shadow-dom-basic.html&test=media%2Fadopt-node-after-showing-picker-crash.html&test=media%2Fadopt-node-crash.html&test=media%2Faudio-controls-adoptNode.html&test=media%2Fmedia-reparent.html&test=media%2Ftrack%2Ftrack-remove-crash.html&test=media%2Fvideo-controls-adoptNode.html&style=debug 2203742 1 webkit-bug-importer 2026-04-23 10:09:27 -0700 <rdar://problem/175436778> 2203744 2 darbinyan 2026-04-23 10:09:59 -0700 *** This bug has been marked as a duplicate of bug 313144 ***