[9445] Possible fix often crashes in waypoint movegen.

Thanks to DrKLO for research source of problem!

src/game/ConfusedMovementGenerator.cpp

@@ -119,6 +119,9 @@ bool ConfusedMovementGenerator<T>::Update(T &unit, const uint32 &diff)
         Traveller<T> traveller(unit);
         if (i_destinationHolder.UpdateTraveller(traveller, diff, false))
         {
+            if (!IsActive(unit))                            // force stop processing (movement can move out active zone with cleanup movegens list)
+                return true;                                // not expire now, but already lost
+
             if (i_destinationHolder.HasArrived())
             {
                 // arrived, stop and wait a bit

src/game/HomeMovementGenerator.cpp

@@ -59,7 +59,11 @@ bool
 HomeMovementGenerator<Creature>::Update(Creature &owner, const uint32& time_diff)
 {
     CreatureTraveller traveller( owner);
-    i_destinationHolder.UpdateTraveller(traveller, time_diff, false);
+    if (i_destinationHolder.UpdateTraveller(traveller, time_diff, false))
+    {
+        if (!IsActive(owner))                               // force stop processing (movement can move out active zone with cleanup movegens list)
+            return true;                                    // not expire now, but already lost
+    }
 
     if (time_diff > i_travel_timer)
     {

src/game/MovementGenerator.cpp

@@ -21,3 +21,10 @@
 MovementGenerator::~MovementGenerator()
 {
 }
+
+bool MovementGenerator::IsActive( Unit& u )
+{
+    // When movement generator list modified from Update movegen object erase delayed,
+    // so pointer still valid and be used for check
+    return !u.GetMotionMaster()->empty() && u.GetMotionMaster()->top() == this;
+}

src/game/MovementGenerator.h

@@ -55,6 +55,10 @@ class MANGOS_DLL_SPEC MovementGenerator
 
         // used by Evade code for select point to evade with expected restart default movement
         virtual bool GetResetPosition(Unit &, float& /*x*/, float& /*y*/, float& /*z*/) { return false; }
+
+        // used for check from Update call is movegen still be active (top movement generator)
+        // after some not safe for this calls
+        bool IsActive(Unit& u);
 };
 
 template<class T, class D>

src/game/RandomMovementGenerator.cpp

@@ -164,6 +164,9 @@ bool RandomMovementGenerator<Creature>::Update(Creature &creature, const uint32
 
     if (i_destinationHolder.UpdateTraveller(traveller, diff, false, true))
     {
+        if (!IsActive(creature))                        // force stop processing (movement can move out active zone with cleanup movegens list)
+            return true;                                // not expire now, but already lost
+
         if (i_nextMoveTime.Passed())
         {
             if (creature.canFly())

src/game/TargetedMovementGenerator.cpp

@@ -149,6 +149,9 @@ bool TargetedMovementGeneratorMedium<T,D>::Update(T &owner, const uint32 & time_
 
     if (i_destinationHolder.UpdateTraveller(traveller, time_diff, false))
     {
+        if (!IsActive(owner))                               // force stop processing (movement can move out active zone with cleanup movegens list)
+            return true;                                    // not expire now, but already lost
+
         // put targeted movement generators on a higher priority
         if (owner.GetObjectSize())
             i_destinationHolder.ResetUpdate(50);

src/game/WaypointMovementGenerator.cpp

@@ -129,7 +129,11 @@ bool WaypointMovementGenerator<Creature>::Update(Creature &creature, const uint3
     CreatureTraveller traveller(creature);
 
     i_nextMoveTime.Update(diff);
-    i_destinationHolder.UpdateTraveller(traveller, diff, false, true);
+    if (i_destinationHolder.UpdateTraveller(traveller, diff, false, true))
+    {
+        if (!IsActive(creature))                            // force stop processing (movement can move out active zone with cleanup movegens list)
+            return true;                                    // not expire now, but already lost
+    }
 
     // creature has been stopped in middle of the waypoint segment
     if (!i_destinationHolder.HasArrived() && creature.IsStopped())
@@ -206,12 +210,11 @@ bool WaypointMovementGenerator<Creature>::Update(Creature &creature, const uint3
             i_hasDone[idx] = true;
             MovementInform(creature);
 
-            // force stop processing (script change movegen list)
-            if (creature.GetMotionMaster()->empty() || creature.GetMotionMaster()->top() != this)
+            if (!IsActive(creature))                        // force stop processing (movement can move out active zone with cleanup movegens list)
                 return true;                                // not expire now, but already lost
 
             // prevent a crash at empty waypoint path.
-            if (!i_path || i_path->empty())
+            if (!i_path || i_path->empty() || i_currentNode >= i_path->size())
             {
                 creature.clearUnitState(UNIT_STAT_ROAMING_MOVE);
                 return true;

src/shared/revision_nr.h

@@ -1,4 +1,4 @@
 #ifndef __REVISION_NR_H__
 #define __REVISION_NR_H__
- #define REVISION_NR "9444"
+ #define REVISION_NR "9445"
 #endif // __REVISION_NR_H__