UE4 Plugin Crashes when swapping levels. (Fix Included)

Question

Since upgradiing to 2017.1.xxxx we started seeing a number of crashes in the editor (could happen in game too!) on level swap. It wasn't terribly common but I root caused it to the fact that "GetWorld" for a component in UE4 can return null when swapping levels. (I.E. the world can be in-accessible during level swap).

Apologies in advance for the formatting. I don't see support for code blocks here.

The crash would occur in this function, but that's not the best place to fix it:

template<class COMPONENT_TYPE>
void FAkAudioDevice::RemovePrioritizedComponentFromList(COMPONENT_TYPE* in_ComponentToRemove, TMap<UWorld*, COMPONENT_TYPE*>& HighestPriorityComponentMap)

 

The fix is pretty simple. Add this to FAkAudioDevice::Init

// OnWorldCleanupDelegateHandle is a new member variable I declared in FAkAudioDevice

OnWorldCleanupDelegateHandle = FWorldDelegates::OnWorldCleanup.AddLambda(
[&](UWorld* WorldBeingCleanedup, bool, bool)
{
   HighestPriorityLateReverbComponentMap.Remove(WorldBeingCleanedup);
   HighestPriorityRoomComponentMap.Remove(WorldBeingCleanedup);
}
);

and add this line to tear down

FWorldDelegates::OnWorldCleanup.Remove(OnWorldCleanupDelegateHandle);