<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<!DOCTYPE bugzilla SYSTEM "https://bugs.webkit.org/page.cgi?id=bugzilla.dtd">

<bugzilla version="5.0.4.1"
          urlbase="https://bugs.webkit.org/"
          
          maintainer="admin@webkit.org"
>

    <bug>
          <bug_id>243867</bug_id>
          
          <creation_ts>2022-08-11 19:58:25 -0700</creation_ts>
          <short_desc>REGRESSION: Occasional assertion failure in JSEventListener::ensureJSFunction via HTMLSlotElement::dispatchSlotChangeEvent()</short_desc>
          <delta_ts>2022-08-11 22:14:16 -0700</delta_ts>
          <reporter_accessible>1</reporter_accessible>
          <cclist_accessible>1</cclist_accessible>
          <classification_id>1</classification_id>
          <classification>Unclassified</classification>
          <product>WebKit</product>
          <component>DOM</component>
          <version>WebKit Nightly Build</version>
          <rep_platform>Unspecified</rep_platform>
          <op_sys>Unspecified</op_sys>
          <bug_status>RESOLVED</bug_status>
          <resolution>FIXED</resolution>
          
          
          <bug_file_loc></bug_file_loc>
          <status_whiteboard></status_whiteboard>
          <keywords>InRadar</keywords>
          <priority>P2</priority>
          <bug_severity>Normal</bug_severity>
          <target_milestone>---</target_milestone>
          
          <blocked>218692</blocked>
          <everconfirmed>1</everconfirmed>
          <reporter name="Ryosuke Niwa">rniwa</reporter>
          <assigned_to name="Ryosuke Niwa">rniwa</assigned_to>
          <cc>webkit-bug-importer</cc>
          

      

      

      

          <comment_sort_order>oldest_to_newest</comment_sort_order>  
          <long_desc isprivate="0" >
    <commentid>1890797</commentid>
    <comment_count>0</comment_count>
    <who name="Ryosuke Niwa">rniwa</who>
    <bug_when>2022-08-11 19:58:25 -0700</bug_when>
    <thetext>e.g.
Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   JavaScriptCore                	       0x5e2d672ce WTFCrash + 14
1   WebCore                       	       0x6002f555b WTFCrashWithInfo(int, char const*, char const*, int) + 27
2   WebCore                       	       0x60302ffea WebCore::JSEventListener::ensureJSFunction(WebCore::ScriptExecutionContext&amp;) const + 602 (JSEventListener.h:157)
3   WebCore                       	       0x60302f3ae WebCore::JSEventListener::handleEvent(WebCore::ScriptExecutionContext&amp;, WebCore::Event&amp;) + 206 (JSEventListener.cpp:141)
4   WebCore                       	       0x60387f18e WebCore::EventTarget::innerInvokeEventListeners(WebCore::Event&amp;, WTF::Vector&lt;WTF::RefPtr&lt;WebCore::RegisteredEventListener, WTF::RawPtrTraits&lt;WebCore::RegisteredEventListener&gt;, WTF::DefaultRefDerefTraits&lt;WebCore::RegisteredEventListener&gt; &gt;, 1ul, WTF::CrashOnOverflow, 2ul, WTF::FastMalloc&gt;, WebCore::EventTarget::EventInvokePhase) + 1022 (EventTarget.cpp:362)
5   WebCore                       	       0x60387ec3e WebCore::EventTarget::fireEventListeners(WebCore::Event&amp;, WebCore::EventTarget::EventInvokePhase) + 302 (EventTarget.cpp:294)
6   WebCore                       	       0x60384aad9 WebCore::EventContext::handleLocalEvents(WebCore::Event&amp;, WebCore::EventTarget::EventInvokePhase) const + 889 (EventContext.cpp:96)
7   WebCore                       	       0x603873606 WebCore::dispatchEventInDOM(WebCore::Event&amp;, WebCore::EventPath const&amp;) + 374 (EventDispatcher.cpp:109)
8   WebCore                       	       0x603872dde WebCore::EventDispatcher::dispatchEvent(WebCore::Node&amp;, WebCore::Event&amp;) + 1038 (EventDispatcher.cpp:190)
9   WebCore                       	       0x6039076bd WebCore::Node::dispatchEvent(WebCore::Event&amp;) + 29 (Node.cpp:2429)
10  WebCore                       	       0x603ce4d6b WebCore::HTMLSlotElement::dispatchSlotChangeEvent() + 139 (HTMLSlotElement.cpp:220)
11  WebCore                       	       0x6038e8007 WebCore::MutationObserver::notifyMutationObservers(WebCore::WindowEventLoop&amp;) + 919 (MutationObserver.cpp:266)
12  WebCore                       	       0x6039e46a4 WebCore::WindowEventLoop::queueMutationObserverCompoundMicrotask()::$_2::operator()() const + 84 (WindowEventLoop.cpp:138)
13  WebCore                       	       0x6039e4609 WTF::Detail::CallableWrapper&lt;WebCore::WindowEventLoop::queueMutationObserverCompoundMicrotask()::$_2, void&gt;::call() + 25 (Function.h:53)
14  WebCore                       	       0x600314902 WTF::Function&lt;void ()&gt;::operator()() const + 130
15  WebCore                       	       0x603883079 WebCore::EventLoopFunctionDispatchTask::execute() + 25 (EventLoop.cpp:159)
16  WebCore                       	       0x6038cfa71 WebCore::MicrotaskQueue::performMicrotaskCheckpoint() + 337 (Microtasks.cpp:64)
17  WebCore                       	       0x60387501e WebCore::EventLoop::performMicrotaskCheckpoint() + 30 (EventLoop.cpp:51)
18  WebCore                       	       0x60387635f WebCore::EventLoopTaskGroup::performMicrotaskCheckpoint() + 63 (EventLoop.cpp:180)
19  WebCore                       	       0x60308becb WebCore::JSExecState::didLeaveScriptContext(JSC::JSGlobalObject*) + 59 (JSExecState.cpp:41)
20  WebCore                       	       0x60303ac37 WebCore::JSExecState::~JSExecState() + 231 (JSExecState.h:175)
21  WebCore                       	       0x60303aa75 WebCore::JSExecState::~JSExecState() + 21 (JSExecState.h:164)</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1890798</commentid>
    <comment_count>1</comment_count>
    <who name="Ryosuke Niwa">rniwa</who>
    <bug_when>2022-08-11 20:04:46 -0700</bug_when>
    <thetext>Pull request: https://github.com/WebKit/WebKit/pull/3256</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1890809</commentid>
    <comment_count>2</comment_count>
    <who name="EWS">ews-feeder</who>
    <bug_when>2022-08-11 22:13:04 -0700</bug_when>
    <thetext>Committed 253365@main (0069c1e3e527): &lt;https://commits.webkit.org/253365@main&gt;

Reviewed commits have been landed. Closing PR #3256 and removing active labels.</thetext>
  </long_desc><long_desc isprivate="0" >
    <commentid>1890810</commentid>
    <comment_count>3</comment_count>
    <who name="Radar WebKit Bug Importer">webkit-bug-importer</who>
    <bug_when>2022-08-11 22:14:16 -0700</bug_when>
    <thetext>&lt;rdar://problem/98549385&gt;</thetext>
  </long_desc>
      
      

    </bug>

</bugzilla>