Entities/Unit: Cleanup all the direct accesses to m_unitMovedByMe. Refactor the field to be protected. Add assertions to catch dangling pointers.

Port From (https://github.com/TrinityCore/TrinityCore/commit/edc75831194bc2419e3abada47121fadf4b2aa8d)

Source/Game/Entities/Player/Player.Fields.cs

@@ -209,8 +209,6 @@ namespace Game.Entities
         public List<ObjectGuid> m_clientGUIDs = new();
         public List<ObjectGuid> m_visibleTransports = new();
         public WorldObject seerView;
-        // only changed for direct client control (possess, vehicle etc.), not stuff you control using pet commands
-        public Unit m_unitMovedByMe;
         Team m_team;
         ReputationMgr reputationMgr;
         QuestObjectiveCriteriaManager m_questObjectiveCriteriaMgr;

Source/Game/Entities/Player/Player.cs

@@ -4013,7 +4013,7 @@ namespace Game.Entities
         public override bool CanAlwaysSee(WorldObject obj)
         {
             // Always can see self
-            if (m_unitMovedByMe == obj)
+            if (GetUnitBeingMoved() == obj)
                 return true;
 
             ObjectGuid guid = m_activePlayerData.FarsightObject;
@@ -5544,7 +5544,7 @@ namespace Game.Entities
             initialSetup.ServerExpansionLevel = (byte)WorldConfig.GetIntValue(WorldCfg.Expansion);
             SendPacket(initialSetup);
 
-            SetMover(this);
+            SetMovedUnit(this);
         }
 
         public void SendInitialPacketsAfterAddToMap()
@@ -7228,18 +7228,7 @@ namespace Game.Entities
                 SetViewpoint(target, allowMove);
 
             if (allowMove)
-                SetMover(target);
+                SetMovedUnit(target);
-        }
-
-        public void SetMover(Unit target)
-        {
-            m_unitMovedByMe.m_playerMovingMe = null;
-            m_unitMovedByMe = target;
-            m_unitMovedByMe.m_playerMovingMe = this;
-
-            MoveSetActiveMover packet = new();
-            packet.MoverGUID = target.GetGUID();
-            SendPacket(packet);
         }
 
         public Item GetWeaponForAttack(WeaponAttackType attackType, bool useable = false)

Source/Game/Entities/Unit/Unit.Fields.cs

@@ -42,8 +42,9 @@ namespace Game.Entities
         MotionMaster i_motionMaster;
         public uint m_movementCounter;       //< Incrementing counter used in movement packets
         TimeTrackerSmall movesplineTimer;
-        public Player m_playerMovingMe;
         MovementForces _movementForces;
+        protected Unit m_unitMovedByMe;    // only ever set for players, and only for direct client control
+        protected Player m_playerMovingMe; // only set for direct client control (possess effects, vehicles and similar)
 
         //Combat
         protected List<Unit> attackerList = new();

Source/Game/Entities/Unit/Unit.Movement.cs

@@ -123,7 +123,7 @@ namespace Game.Entities
                 }
             }
 
-            Player playerMover = GetPlayerBeingMoved(); // unit controlled by a player.
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer(); // unit controlled by a player.
             if (playerMover)
             {
                 // Send notification to self
@@ -244,7 +244,7 @@ namespace Game.Entities
                 if (charmer)
                 {
                     player = charmer.ToPlayer();
-                    if (player && player.m_unitMovedByMe != this)
+                    if (player && player.GetUnitBeingMoved() != this)
                         player = null;
                 }
             }
@@ -287,7 +287,7 @@ namespace Game.Entities
             else
                 RemoveUnitMovementFlag(MovementFlag.DisableCollision);
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(disable ? ServerOpcodes.MoveSplineEnableCollision : ServerOpcodes.MoveEnableCollision);
@@ -322,7 +322,7 @@ namespace Game.Entities
             else
                 RemoveUnitMovementFlag2(MovementFlag2.CanSwimToFlyTrans);
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveEnableTransitionBetweenSwimAndFly : ServerOpcodes.MoveDisableTransitionBetweenSwimAndFly);
@@ -349,7 +349,7 @@ namespace Game.Entities
             else
                 RemoveUnitMovementFlag2(MovementFlag2.CanTurnWhileFalling);
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveSetCanTurnWhileFalling : ServerOpcodes.MoveUnsetCanTurnWhileFalling);
@@ -375,7 +375,7 @@ namespace Game.Entities
             else
                 RemoveUnitMovementFlag2(MovementFlag2.CanDoubleJump);
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveEnableDoubleJump : ServerOpcodes.MoveDisableDoubleJump);
@@ -672,7 +672,7 @@ namespace Game.Entities
                 RemoveUnitMovementFlag(MovementFlag.DisableGravity);
 
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(disable ? ServerOpcodes.MoveDisableGravity : ServerOpcodes.MoveEnableGravity);
@@ -816,8 +816,8 @@ namespace Game.Entities
                 }
         }
     }
-
+        
-    public override void ProcessPositionDataChanged(PositionFullTerrainStatus data)
+        public override void ProcessPositionDataChanged(PositionFullTerrainStatus data)
         {
             base.ProcessPositionDataChanged(data);
             ProcessTerrainStatusUpdate(data.LiquidStatus, data.LiquidInfo);
@@ -922,7 +922,7 @@ namespace Game.Entities
             if (!enable && IsTypeId(TypeId.Player))
                 ToPlayer().SetFallInformation(0, GetPositionZ());
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveSetCanFly : ServerOpcodes.MoveUnsetCanFly);
@@ -955,7 +955,7 @@ namespace Game.Entities
                 RemoveUnitMovementFlag(MovementFlag.WaterWalk);
 
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveSetWaterWalk : ServerOpcodes.MoveSetLandWalk);
@@ -988,7 +988,7 @@ namespace Game.Entities
                 RemoveUnitMovementFlag(MovementFlag.FallingSlow);
 
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveSetFeatherFall : ServerOpcodes.MoveSetNormalFall);
@@ -1036,7 +1036,7 @@ namespace Game.Entities
                 }
             }
 
-            Player playerMover = GetPlayerBeingMoved();
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 MoveSetFlag packet = new(enable ? ServerOpcodes.MoveSetHovering : ServerOpcodes.MoveUnsetHovering);
@@ -1107,6 +1107,17 @@ namespace Game.Entities
             }
         }
 
+        public void SetMovedUnit(Unit target)
+        {
+            m_unitMovedByMe.m_playerMovingMe = null;
+            m_unitMovedByMe = target;
+            m_unitMovedByMe.m_playerMovingMe = ToPlayer();
+
+            MoveSetActiveMover packet = new();
+            packet.MoverGUID = target.GetGUID();
+            ToPlayer().SendPacket(packet);
+        }
+
         public void SetControlled(bool apply, UnitState state)
         {
             if (apply)
@@ -1254,7 +1265,7 @@ namespace Game.Entities
                     RemoveUnitMovementFlag(MovementFlag.Root);
             }
 
-            Player playerMover = GetPlayerBeingMoved();// unit controlled by a player.
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();// unit controlled by a player.
             if (playerMover)
             {
                 MoveSetFlag packet = new(apply ? ServerOpcodes.MoveRoot : ServerOpcodes.MoveUnroot);
@@ -1624,14 +1635,7 @@ namespace Game.Entities
             SendMessageToSet(data, true);
         }
 
-        public Unit GetUnitBeingMoved()
+        public Unit GetUnitBeingMoved() { return m_unitMovedByMe; }
-        {
-            Player player = ToPlayer();
-            if (player)
-                return player.m_unitMovedByMe;
-
-            return null;
-        }
 
         Player GetPlayerBeingMoved()
         {
@@ -1759,7 +1763,8 @@ namespace Game.Entities
                 moveUpdateTeleport.MovementForces = _movementForces.GetForces();
             Unit broadcastSource = this;
 
-            Player playerMover = GetPlayerBeingMoved();
+            // should this really be the unit _being_ moved? not the unit doing the moving?
+            Player playerMover = GetUnitBeingMoved()?.ToPlayer();
             if (playerMover)
             {
                 float x, y, z, o;

Source/Game/Handlers/SpellHandler.cs

@@ -37,7 +37,7 @@ namespace Game
             Player user = GetPlayer();
 
             // ignore for remote control state
-            if (user.m_unitMovedByMe != user)
+            if (user.GetUnitBeingMoved() != user)
                 return;
 
             Item item = user.GetUseableItemByPos(packet.PackSlot, packet.Slot);
@@ -133,7 +133,7 @@ namespace Game
             Player player = GetPlayer();
 
             // ignore for remote control state
-            if (player.m_unitMovedByMe != player)
+            if (player.GetUnitBeingMoved() != player)
                 return;
 
             // additional check, client outputs message on its own
@@ -243,8 +243,8 @@ namespace Game
             if (obj)
             {
                 // ignore for remote control state
-                if (GetPlayer().m_unitMovedByMe != GetPlayer())
+                if (GetPlayer().GetUnitBeingMoved() != GetPlayer())
-                    if (!(GetPlayer().IsOnVehicle(GetPlayer().m_unitMovedByMe) || GetPlayer().IsMounted()) && !obj.GetGoInfo().IsUsableMounted())
+                    if (!(GetPlayer().IsOnVehicle(GetPlayer().GetUnitBeingMoved()) || GetPlayer().IsMounted()) && !obj.GetGoInfo().IsUsableMounted())
                         return;
 
                 obj.Use(GetPlayer());
@@ -255,7 +255,7 @@ namespace Game
         void HandleGameobjectReportUse(GameObjReportUse packet)
         {
             // ignore for remote control state
-            if (GetPlayer().m_unitMovedByMe != GetPlayer())
+            if (GetPlayer().GetUnitBeingMoved() != GetPlayer())
                 return;
 
             GameObject go = GetPlayer().GetGameObjectIfCanInteractWith(packet.Guid);
@@ -272,7 +272,7 @@ namespace Game
         void HandleCastSpell(CastSpell cast)
         {
             // ignore for remote control state (for player case)
-            Unit mover = GetPlayer().m_unitMovedByMe;
+            Unit mover = GetPlayer().GetUnitBeingMoved();
             if (mover != GetPlayer() && mover.IsTypeId(TypeId.Player))
                 return;
 
@@ -472,7 +472,7 @@ namespace Game
         void HandleCancelChanneling(CancelChannelling cancelChanneling)
         {
             // ignore for remote control state (for player case)
-            Unit mover = _player.m_unitMovedByMe;
+            Unit mover = _player.GetUnitBeingMoved();
             if (mover != _player && mover.IsTypeId(TypeId.Player))
                 return;
 
@@ -483,7 +483,7 @@ namespace Game
         void HandleTotemDestroyed(TotemDestroyed totemDestroyed)
         {
             // ignore for remote control state
-            if (GetPlayer().m_unitMovedByMe != GetPlayer())
+            if (GetPlayer().GetUnitBeingMoved() != GetPlayer())
                 return;
 
             byte slotId = totemDestroyed.Slot;