"Bug" UMG Crash "Button Visibility Function"

In-game testing crashes when widget “Button” is called to appear with a boolean branch.

MachineId:B305E71A40F9C6AE70063AA108B06C57
EpicAccountId:ba8348aab43d45c5bea8211e4b49afc6

Unknown exception - code 00000001 (first/second chance not available)

Assertion failed: false [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\UMG\Private\Components\Widget.cpp] [Line: 551]

KERNELBASE + 24684 bytes
UE4Editor_Core!FOutputDeviceWindowsError::Serialize() + 292 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\windows\windowsplatformoutputdevices.cpp:95]
UE4Editor_Core!FOutputDevice::Logf__VA() + 248 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:144]
UE4Editor_Core!FDebug::AssertFailed() + 1079 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\core\private\misc\outputdevice.cpp:224]
UE4Editor_UMG!UWidget::ConvertSerializedVisibilityToRuntime() + 85 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\umg\private\components\widget.cpp:541]
UE4Editor_UMG!UWidget::ConvertVisibility() + 72 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\umg\public\components\widget.h:368]
UE4Editor_UMG!TMemberFunctionCaller)const ptr64>::operator() const & ptr64>() + 79 bytes [d:\buildfarm\buildmachine++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegateinstanceinterface_variadics.h:162]
UE4Editor_UMG!TBaseUObjectMethodDelegateInstance<1,UWidget,EVisibility cdecl(void),TAttribute >::Execute() + 271 bytes [d:\buildfarm\buildmachine++depot+ue4-releases+4.7\engine\source\runtime\core\public\delegates\delegateinstancesimpl_variadics.inl:682]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 129 bytes [d:\buildfarm\buildmachine
++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:377]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine
++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine
++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine
++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_SlateCore!SWidget::SlatePrepass() + 163 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slatecore\private\widgets\swidget.cpp:380]
UE4Editor_Slate!PrepassWindowAndChildren() + 548 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:984]
UE4Editor_Slate!FSlateApplication::DrawPrepass() + 551 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1029]
UE4Editor_Slate!FSlateApplication::PrivateDrawWindows() + 523 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1068]
UE4Editor_Slate!FSlateApplication::Tick() + 2879 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\slate\private\framework\application\slateapplication.cpp:1323]
UE4Editor!FEngineLoop::Tick() + 4447 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launchengineloop.cpp:2284]
UE4Editor!GuardedMain() + 1404 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() + 26 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() + 249 bytes [d:\buildfarm\buildmachine_++depot+ue4-releases+4.7\engine\source\runtime\launch\private\windows\launchwindows.cpp:202]
UE4Editor!__tmainCRTStartup() + 329 bytes [f:\dd\vctools\crt\crtw32\dllstuff\crtexe.c:618]

Hello Fruity,

After looking over your issue, I found that the editor is crashing because your binding is not always getting a return value. If you connect the execution pin from the print string to the return node, this will prevent the crash that you are experiencing. I hope this this helps.

Make it a great day