Core/Transports: Delayed adding transport model to next tick after teleporting to fix race conditions happening when teleporting transport happens at the same time as destination map balances its dynamic LoS tree

3 files changed, 20 insertions, 3 deletions

diff --git a/src/server/game/Entities/GameObject/GameObject.cpp b/src/server/game/Entities/GameObject/GameObject.cpp
index ee39ed48ad6..c8c0eaefb27 100644
--- a/src/server/game/Entities/GameObject/GameObject.cpp
+++ b/src/server/game/Entities/GameObject/GameObject.cpp
@@ -143,7 +143,12 @@ void GameObject::AddToWorld()
         // The state can be changed after GameObject::Create but before GameObject::AddToWorld
         bool toggledState = GetGoType() == GAMEOBJECT_TYPE_CHEST ? getLootState() == GO_READY : (GetGoState() == GO_STATE_READY || IsTransport());
         if (m_model)
-            GetMap()->InsertGameObjectModel(*m_model);
+        {
+            if (Transport* trans = ToTransport())
+                trans->SetDelayedAddModelToMap();
+            else
+                GetMap()->InsertGameObjectModel(*m_model);
+        }
 
         EnableCollision(toggledState);
         WorldObject::AddToWorld();
diff --git a/src/server/game/Entities/Transport/Transport.cpp b/src/server/game/Entities/Transport/Transport.cpp
index d907274f8d1..367ccd34cdb 100644
--- a/src/server/game/Entities/Transport/Transport.cpp
+++ b/src/server/game/Entities/Transport/Transport.cpp
@@ -35,7 +35,8 @@
 
 Transport::Transport() : GameObject(),
     _transportInfo(NULL), _isMoving(true), _pendingStop(false),
-    _triggeredArrivalEvent(false), _triggeredDepartureEvent(false), _passengerTeleportItr(_passengers.begin())
+    _triggeredArrivalEvent(false), _triggeredDepartureEvent(false),
+    _passengerTeleportItr(_passengers.begin()), _delayedAddModel(false)
 {
     m_updateFlag = UPDATEFLAG_TRANSPORT | UPDATEFLAG_LOWGUID | UPDATEFLAG_STATIONARY_POSITION | UPDATEFLAG_ROTATION;
 }
@@ -186,6 +187,14 @@ void Transport::Update(uint32 diff)
                 return; // Update more in new map thread
     }
 
+    // Add model to map after we are fully done with moving maps
+    if (_delayedAddModel)
+    {
+        _delayedAddModel = false;
+        if (m_model)
+            GetMap()->InsertGameObjectModel(*m_model);
+    }
+
     // Set position
     _positionChangeTimer.Update(diff);
     if (_positionChangeTimer.Passed())
@@ -625,7 +634,6 @@ bool Transport::TeleportTransport(uint32 newMapid, float x, float y, float z, fl
         }
 
         Relocate(x, y, z, o);
-        UpdateModelPosition();
         GetMap()->AddToMap<Transport>(this);
         return true;
     }
diff --git a/src/server/game/Entities/Transport/Transport.h b/src/server/game/Entities/Transport/Transport.h
index e644417f1ac..2c924eb33ed 100644
--- a/src/server/game/Entities/Transport/Transport.h
+++ b/src/server/game/Entities/Transport/Transport.h
@@ -95,6 +95,8 @@ class Transport : public GameObject, public TransportBase
 
         void EnableMovement(bool enabled);
 
+        void SetDelayedAddModelToMap() { _delayedAddModel = true; }
+
         TransportTemplate const* GetTransportTemplate() const { return _transportInfo; }
 
     private:
@@ -123,6 +125,8 @@ class Transport : public GameObject, public TransportBase
         PassengerSet _passengers;
         PassengerSet::iterator _passengerTeleportItr;
         PassengerSet _staticPassengers;
+
+        bool _delayedAddModel;
 };
 
 #endif