[Bug Probability] UE4 Assertion Falied: index >= 0

Scalibur · March 1, 2018, 3:52am

Hi, I’m working on an unreal project which is mostly done in c ++ but when I give it play at some random part of time within it, the editor and the game shows an error which is not in my code. It seems that this is in the engine code which makes me doubt that it is my mistake or if the engine really has the problem.
I leave the “Log” of the error:

Assertion failed: Index >= 0 [File:D:\Build\++UE4+Release-4.18+Compile\Sync\Engine\Source\Runtime\CoreUObject\Public\UObject/UObjectArray.h] [Line: 445]

UE4Editor_Core!FDebug::AssertFailed() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\misc\assertionmacros.cpp:414]
UE4Editor_CoreUObject!UObject::ProcessContextOpcode() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:2158]
UE4Editor_CoreUObject!UObject::execLet() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1953]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UObject::CallFunction() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:856]
UE4Editor_CoreUObject!UObject::ProcessInternal() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:954]
UE4Editor_CoreUObject!UFunction::Invoke() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\class.cpp:4542]
UE4Editor_CoreUObject!UObject::ProcessEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\coreuobject\private\uobject\scriptcore.cpp:1314]
UE4Editor_Engine!AActor::ProcessEvent() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:693]
UE4Editor_Engine!AActor::ReceiveTick()
UE4Editor_Engine!AActor::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:896]
UE4Editor_Engine!AActor::TickActor() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:878]
UE4Editor_Engine!FActorTickFunction::ExecuteTick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\actor.cpp:132]
UE4Editor_Engine!FTickFunctionTask::DoTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:273]
UE4Editor_Engine!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\public\async\taskgraphinterfaces.h:784]
UE4Editor_Core!FNamedTaskThread::ProcessTasksNamedThread() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:651]
UE4Editor_Core!FNamedTaskThread::ProcessTasksUntilQuit() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:560]
UE4Editor_Core!FTaskGraphImplementation::WaitUntilTasksComplete() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\core\private\async\taskgraph.cpp:1330]
UE4Editor_Engine!FTickTaskSequencer::ReleaseTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:542]
UE4Editor_Engine!FTickTaskManager::RunTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\ticktaskmanager.cpp:1454]
UE4Editor_Engine!UWorld::RunTickGroup() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:760]
UE4Editor_Engine!UWorld::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\engine\private\leveltick.cpp:1408]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\editorengine.cpp:1659]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\editor\unrealed\private\unrealedengine.cpp:396]
UE4Editor!FEngineLoop::Tick() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launchengineloop.cpp:3296]
UE4Editor!GuardedMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\launch.cpp:166]
UE4Editor!GuardedMainWrapper() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:134]
UE4Editor!WinMain() [d:\build\++ue4+release-4.18+compile\sync\engine\source\runtime\launch\private\windows\launchwindows.cpp:210]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:253]
kernel32
ntdll

Here Screen of the Crash Reporter:

Thanks in advance.

AmphDev · March 1, 2018, 10:06am

Hello!

Thats definitly not bug, you tried to get element from an Array, but that element and index isnt exist so it is invalid…
Check your array operations and always use “IndexIsValid(index)” before you do array operation, so you can avoid crashes…

Tip: because of callstack does not show any special c++ code from your game i guess some blueprint class / script try to get invalid index from an array…

If your source is c++ try to use windows debugger (f5 in vs) to get better callstack and with that you can identify which event was called before the assert…

cheers

Scalibur · March 1, 2018, 11:00pm

thanks “AmphDev”. I followed your advice in executing it with the visual studio debugger and there were errors that were not shown in the editor of unreal. the problem was a puter that was null and indirectly changed an array which threw that assertion falied.