avoid shared_from_this while constructing

libraries/avatars/src/AvatarData.cpp

@@ -60,6 +60,7 @@ AvatarData::AvatarData() :
     setBodyPitch(0.0f);
     setBodyYaw(-90.0f);
     setBodyRoll(0.0f);
+    _constructing = false;
 }
 
 AvatarData::~AvatarData() {

libraries/entities/src/EntityItem.cpp

@@ -85,6 +85,7 @@ EntityItem::EntityItem(const EntityItemID& entityItemID) :
     quint64 now = usecTimestampNow();
     _lastSimulated = now;
     _lastUpdated = now;
+    _constructing = false;
 }
 
 EntityItem::~EntityItem() {

libraries/shared/src/SpatiallyNestable.cpp

@@ -32,6 +32,11 @@ SpatiallyNestablePointer SpatiallyNestable::getParentPointer() const {
         return nullptr;
     }
 
+    if (_constructing) {
+        // we can't use shared_from_this yet, so stop here.
+        return nullptr;
+    }
+
     SpatiallyNestableConstPointer constThisPointer = shared_from_this();
     SpatiallyNestablePointer thisPointer = std::const_pointer_cast<SpatiallyNestable>(constThisPointer); // ermahgerd !!!
 

libraries/shared/src/SpatiallyNestable.h

@@ -82,6 +82,8 @@ public:
     NestableTypes::NestableType getNestableType() const { return _nestableType; }
 
 protected:
+    bool _constructing = true;
+
     NestableTypes::NestableType _nestableType; // EntityItem or an AvatarData
     QUuid _id;
     QUuid _parentID; // what is this thing's transform relative to?