Crashing during hot reload when --track-widget-creation is enabled

vscode extension Dart was upgraded to 2.17.0. Running with “Start Debugging F5”. Using iOS simulator, iPhone X, iOS 11.1. Any minor change, even adding in whitespace, and Saving (cmd-s), causing a hot reload, results in the following

../../third_party/dart/runtime/vm/object.h: 8847: error: Handle check failed: saw Instance of 'HomePage' expected Closure
Dumping native stack trace for thread 5c03
[0x00000001008ac0d4] dart::Profiler::DumpStackTrace(void*)
[0x00000001008ac0d4] dart::Profiler::DumpStackTrace(void*)
[0x0000000100b20142] dart::Assert::Fail(char const*, ...)
[0x0000000100903f3b] dart::DRT_InvokeClosureNoSuchMethod(dart::NativeArguments)
[0x000000011678085b] [Stub] CallToRuntime
[0x0000000116782dc4] [Stub] CallClosureNoSuchMethod
[0x000000011f3be9cb] new HomePage
[0x000000011f3be69a] MyApp.build
[0x000000011c179714] StatelessElement.build
[0x000000011c178a5e] ComponentElement.performRebuild
[0x000000011c177bc1] Element.rebuild
[0x000000011c16b1d0] BuildOwner.buildScope
[0x00000001169c1370] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding&WidgetsBinding.drawFrame
[0x00000001169c0f68] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding._handlePersistentFrameCallback
[0x00000001169c0d7f] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding&PaintingBinding&RendererBinding._handlePersistentFrameCallback
[0x00000001188e68b5] _Closure.call
[0x00000001169c0796] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding._invokeFrameCallback
[0x000000011c480b28] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.handleDrawFrame
[0x000000011ca2680b] _WidgetsFlutterBinding&BindingBase&GestureBinding&ServicesBinding&SchedulerBinding.scheduleWarmUpFrame.<anonymous closure>
[0x00000001188c0512] _Closure.call
[0x000000011cf7f96d] Timer._createTimer.<anonymous closure>
[0x00000001188e68b5] _Closure.call
[0x000000011cf7ea75] _Timer._runTimers
[0x00000001169bdc32] _Timer._handleMessage
[0x00000001169bd73b] _Timer._handleMessage
[0x00000001188e68b5] _Closure.call
[0x00000001188e67bc] _RawReceivePortImpl._handleMessage
[0x0000000116780ce3] [Stub] InvokeDartCode
[0x00000001007637c9] dart::DartEntry::InvokeFunction(dart::Function const&, dart::Array const&, dart::Array const&, unsigned long)
[0x0000000100766f0e] dart::DartLibraryCalls::HandleMessage(dart::Object const&, dart::Instance const&)
[0x0000000100792ed6] dart::IsolateMessageHandler::HandleMessage(dart::Message*)
[0x00000001007bdfee] dart::MessageHandler::HandleMessages(dart::MonitorLocker*, bool, bool)
[0x00000001007be0f0] dart::MessageHandler::HandleNextMessage()
[0x0000000100aa0175] Dart_HandleMessage
[0x00000001005ef285] tonic::DartMessageHandler::OnHandleMessage(tonic::DartState*)
[0x000000010027c222] fml::MessageLoopImpl::RunExpiredTasks()
[0x000000010027ef1a] fml::MessageLoopDarwin::OnTimerFire(__CFRunLoopTimer*, fml::MessageLoopDarwin*)
[0x00000001028832a4] __CFRUNLOOP_IS_CALLING_OUT_TO_A_TIMER_CALLBACK_FUNCTION__
[0x0000000102882f62] __CFRunLoopDoTimer
[0x0000000102882b1a] __CFRunLoopDoTimers
[0x000000010287a534] __CFRunLoopRun
[0x00000001028799b9] CFRunLoopRunSpecific
[0x000000010027f06b] fml::MessageLoopDarwin::Run()
[0x000000010027c359] fml::MessageLoopImpl::DoRun()
[0x000000010027ea70] std::__1::__thread_proxy<std::__1::tuple<std::__1::unique_ptr<std::__1::__thread_struct, std::__1::default_delete<std::__1::__thread_struct> >, fml::Thread::Thread(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&)::$_0> >(void*, void*)
[0x0000000107ec8661] _pthread_body
[0x0000000107ec850d] _pthread_body
[0x0000000107ec7bf9] thread_start
Lost connection to device.
-- End of DumpStackTrace
Exited (sigterm)

Also logged here https://github.com/flutter/flutter/issues/20191. Could this be related to the “Inspect Flutter Widget” feature added?

[DanTup]

That’s the only thing I could think could have caused this to appear in this version, since there’s not really anything else that’d affect how flutter run behaves.

Can you try setting "dart.flutterTrackWidgetCreation": false in your VS Code settings and see if that fixes things?

[DanTup]

@LJame the crash that this is case referred to was actually fixed prior to Flutter 1.0 (so we re-enabled it by default in #1277) though I forgot to resolve this. If you’re on Flutter >= 1.0 and seeing crashes only when track-widget-creation is enabled, would you mind opening at https://github.com/flutter/flutter?

If you do need to disable it, the instructions Devon gave above apply to both IntelliJ and Android Studio:

Hope this helps!