Referencing parent components

I’d like to make it so that, if a UPrimitiveComponent that simulates physics has an AttachParent that also simulates physics, the constraint configured for the child is tied to the parent, rather than tied to world space.
I believe that the change can be made locally in BodyInstance.cpp:

		DOFConstraint->PriAxis2 = Normal;
		DOFConstraint->SecAxis2 = Sec;
		DOFConstraint->Pos2 = TM.GetLocation();

		FBodyInstance *parentBody = nullptr;
		UPrimitiveComponent *parentComponent = OwnerComponent.Get();
		if (parentComponent != nullptr) {
			parentComponent = Cast<UPrimitiveComponent>(parentComponent->GetAttachParent());
		if (parentComponent != nullptr) {
			//	TODO: parentComponent is gotten from a weak pointer; how long will
			//	this body pointer live?
			parentBody = parentComponent->GetBodyInstance();


		// Create constraint instance based on DOF
		DOFConstraint->InitConstraint(this, parentBody, 1.f, OwnerComponent.Get());

However, I’m concerned that getting a pointer to a bodystate in the parent is dangerous, because the component pointer is a weak pointer!
Also, the BodyState is an inline struct in the parent component.

What do I need to do to make sure that dangling references to the parent aren’t kept around?
My initial idea is to recreate the physics state inside UPrimitiveComponent::OnAttachmentChanged(), but I don’t know if that will be enough, and I also don’t know if that will be unnecessarily heavy-handed:

void UPrimitiveComponent::OnAttachmentChanged()
	UWorld* World = GetWorld();
	if (World && World->Scene)
	/* We only need to recreate physics state if we had a physical parent component 
	   that was used for the constraint. Moving physically simulated component attachment 
	   should be rare enough that optimizing for that shouldn't be necessary. */

So, advice and pointers appreciated!

Oddly, adding the parent component’s body to the joint doesn’t seem to be enough to cause the physics bodies to link together.
When I create a small chain that is parented, I can see the bodies of each object get linked through the call to InitConstraint(), but the bodies still stay pinned in world space.
I traced through all the way down to the PhysX library calls, and it seems like it’s doing the right thing, but obviously I’m missing something or getting something wrong.

Progress! Further questions in this thread: Allowing hierarchical armatures of primitive components in a single actor (patch) - C++ Gameplay Programming - Unreal Engine Forums