Behavior Tree "Gotchas"

[nakedeyes]

@Bino

Bit of a long shot as this is an old thread but thought I’d see… I just upgraded to 4.25 preview 7 and I’m having issues with AISystem.cpp. In particular the registering and unregistering of components.

The *check *at the bottom always fires now and the ensure sometimes fires. It’s hard to make out what’s going on as values are optimized away. This wasn’t occurring in 4.24.

For the *check * I think it’s reference to an the AI actor controller hanging around. Or maybe it’s not being removed by RemoveSingle??

Feedback: I quite like the AI system but I’m ready to ditch it. It’s by far the biggest time sink in debugging issues and just getting it to work for this project. I can a lot of love and thought was put into it but when using it in anger… it’s hell.

void UAISystem::UnregisterBlackboardComponent(UBlackboardData& BlackboardData, UBlackboardComponent& BlackboardComp)
{
// this is actually possible, we can end up unregistering before UBlackboardComponent cached its BrainComponent
// which currently is tied to the whole process.
// @todo remove this dependency
**ensure(BlackboardDataToComponentsMap.FindPair(&BlackboardData, &BlackboardComp) != nullptr);**

if (BlackboardData.Parent)
{
UnregisterBlackboardComponent(*BlackboardData.Parent, BlackboardComp);
}
BlackboardDataToComponentsMap.RemoveSingle(&BlackboardData, &BlackboardComp);

// mismatch of Register/Unregister.
** check(BlackboardDataToComponentsMap.FindPair(&BlackboardData, &BlackboardComp) == nullptr);**
}

I am experiencing this exact issue. I have been fine thus far, by kicking off my AI in my controllers via:

GameLevelAIController::OnPosses()

I would call in C++ :

 
         // Set up Blackboard and Behavior Tree         UBlackboardComponent* BBCompPointer;         UseBlackboard(BlackboardAsset, BBCompPointer); 

I am doing this instead of manually managing A Blackboard component on the controller class / BP ( maybe that is bad )… but just by calling that in my game code, I get the ensure you pointed out due to the Blackboard Component getting initialized twice and not handling it correctly, which totally crashes a packaged build and although its fine in editor for me, it does endlessly hit the ensure in UnregisterBlackboardComponent().

I think this is a legit new bug in 4.25. Hope for fix or work around soon!