Multi versions of Unreal Crash when I try to open my project

[michaelswallace]

Hello,

I am on Section 3 Lesson 71. After I add the new AActor Component OpenDoor the engine crashes. I am using Unreal 4.19.2 and Microsoft Visual C++ 2017. I have started the project over from scratch twice now with the same results. I included the log file from BuildingEscape/Saved/Logs and these 4 files Opendoor.h, .cpp, PositionReport.cpp, .h in BuildingEscape.zip.

I felt like I was making good progress but this issue has kicked my butt the last 2 evenings and Sunday. Any help is greatly appreciated.

Thank you, MikeW

BuildingEscape.zip (2.6 KB)

BuildingEscape-backup-2019.02.12-18.35.54.log.zip (6.6 KB)

[DanM]

Because you’re calling code in the constructor that would return nullptr

UOpenDoor::UOpenDoor()
{
	// Set this component to be initialized when the game starts, and to be ticked every frame.  You can turn these features
	// off to improve performance if you don't need them.
	PrimaryComponentTick.bCanEverTick = true;

	// Find the owning actor
    //////////////////////////////////////////
	FString ObjectName = GetOwner()->GetName();
	FString ObjectPos = GetOwner()->GetTransform().GetLocation().ToString();
    ///////////////////////////////////////////
	UE_LOG(LogTemp, Warning, TEXT("%s is at %s"), *ObjectName, *ObjectPos);
}

The code within the //'s is problematic. GetOwner() would return nullptr in the constructor as the component doesn’t have an owner at that stage and you are then dereferencing the by using ->. Dereferencing a nullptr is undefined behaviour and causes Unreal to crash.

Only the first line should be in the constructor.