Tick Causes Crash

Development Programming & Scripting
1

As far as I understand, my tick causes crash and I cannot figure out why. Anyone can lead me to the solution?

It ticks about 1 min and crashes. The Tick is in a GameMode.

The Tick Method:

void ASingleBattleMode::Tick(float DeltaSeconds)
{
	Super::Tick(DeltaSeconds);
	CurrentState->Tick(DeltaSeconds); // line number 31
	if (CurrentState->IsCompleted()) {
		if (CurrentState->NextState != NULL) {
			CurrentState = CurrentState->NextState;
			CurrentState->GameMode = this;
			CurrentState->Setup();
		}
	}
}

This is the error I get:

Access violation - code c0000005 (first/second chance not available)

""

UE4Editor_HeroMasters_7416!ASingleBattleMode::Tick() [c:\users\erayt\documents\unreal projects\heromasters\source\heromasters\singlebattlemode.cpp:31]
UE4Editor_Engine!AActor::TickActor() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\actor.cpp:730]
UE4Editor_Engine!FActorTickFunction::ExecuteTick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\actor.cpp:107]
UE4Editor_Engine!FTickFunctionTask::DoTask() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\ticktaskmanager.cpp:141]
UE4Editor_Engine!TGraphTask<FTickFunctionTask>::ExecuteTask() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\public\async\taskgraphinterfaces.h:779]
UE4Editor_Core!FTaskThread::ProcessTasks() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:539]
UE4Editor_Core!FTaskThread::ProcessTasksUntilQuit() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:340]
UE4Editor_Core!FTaskGraphImplementation::WaitUntilTasksComplete() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\private\async\taskgraph.cpp:1140]
UE4Editor_Engine!FTaskGraphInterface::WaitUntilTaskCompletes() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\core\public\async\taskgraphinterfaces.h:212]
UE4Editor_Engine!FTickTaskSequencer::ReleaseTickGroup() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\ticktaskmanager.cpp:285]
UE4Editor_Engine!FTickTaskManager::RunTickGroup() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\ticktaskmanager.cpp:1206]
UE4Editor_Engine!UWorld::RunTickGroup() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\leveltick.cpp:701]
UE4Editor_Engine!UWorld::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\engine\private\leveltick.cpp:1150]
UE4Editor_UnrealEd!UEditorEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\unrealed\private\editorengine.cpp:1347]
UE4Editor_UnrealEd!UUnrealEdEngine::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\editor\unrealed\private\unrealedengine.cpp:361]
UE4Editor!FEngineLoop::Tick() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\launchengineloop.cpp:2427]
UE4Editor!GuardedMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\launch.cpp:142]
UE4Editor!GuardedMainWrapper() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\windows\launchwindows.cpp:126]
UE4Editor!WinMain() [d:\buildfarm\buildmachine_++depot+ue4-releases+4.10\engine\source\runtime\launch\private\windows\launchwindows.cpp:200]
UE4Editor!__scrt_common_main_seh() [f:\dd\vctools\crt\vcstartup\src\startup\exe_common.inl:264]
kernel32
ntdll
2

Show us code of your tick function and mark 31 line of this code.

3

Updated my question. Is it something that at some point my state is removed by garbage collector or sth?

4

Yep it seems the CurrentState is gced, you should wrap it with UPROPERTY() macro or use TWeakPtr and check if it is valid before use it.

5

I have added UPROPERTY macro inside my GameMode holding CurrentState so that it is not removed by Garbage Collector of UE.

	UPROPERTY()
	class UBattleState* CurrentState;

More Information:
Garbage Collection

In the article it says:

you must have at least 1 reference to the UObject that is UPROPERTY()

Additionally, I would like to thank the user @Pierdek for leading the solution.