Core/Scripts: Fixed ENSURE_AI assertion failures when used in Reset()/InitializeAI() hooks with hotswap

Updates #20727

3 files changed, 16 insertions, 2 deletions

diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index c7b25d610a2..4036a8743e0 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/src/server/game/Entities/Creature/Creature.cpp
@@ -981,7 +981,7 @@ bool Creature::AIM_Destroy()
     return true;
 }
 
-bool Creature::AIM_Initialize(CreatureAI* ai)
+bool Creature::AIM_Create(CreatureAI* ai /*= nullptr*/)
 {
     // make sure nothing can change the AI during AI update
     if (m_AI_locked)
@@ -995,12 +995,23 @@ bool Creature::AIM_Initialize(CreatureAI* ai)
     Motion_Initialize();
 
     i_AI = ai ? ai : FactorySelector::SelectAI(this);
+}
 
+void Creature::AI_InitializeAndEnable()
+{
     IsAIEnabled = true;
     i_AI->InitializeAI();
     // Initialize vehicle
     if (GetVehicleKit())
         GetVehicleKit()->Reset();
+}
+
+bool Creature::AIM_Initialize(CreatureAI* ai)
+{
+    if (!AIM_Create(ai))
+        return false;
+
+    AI_InitializeAndEnable();
     return true;
 }
 
diff --git a/src/server/game/Entities/Creature/Creature.h b/src/server/game/Entities/Creature/Creature.h
index 84d00777e9b..0aa74aabf58 100644
--- a/src/server/game/Entities/Creature/Creature.h
+++ b/src/server/game/Entities/Creature/Creature.h
@@ -130,6 +130,8 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
         bool IsEvadingAttacks() const { return IsInEvadeMode() || CanNotReachTarget(); }
 
         bool AIM_Destroy();
+        bool AIM_Create(CreatureAI* ai = nullptr);
+        void AI_InitializeAndEnable();
         bool AIM_Initialize(CreatureAI* ai = nullptr);
         void Motion_Initialize();
 
diff --git a/src/server/game/Scripting/ScriptMgr.cpp b/src/server/game/Scripting/ScriptMgr.cpp
index 2b8acfa67d1..cbee458c9a0 100644
--- a/src/server/game/Scripting/ScriptMgr.cpp
+++ b/src/server/game/Scripting/ScriptMgr.cpp
@@ -421,7 +421,7 @@ class CreatureGameObjectScriptRegistrySwapHooks
         if (creature->IsAlive())
             creature->ClearUnitState(UNIT_STATE_EVADE);
 
-        bool const created = creature->AIM_Initialize();
+        bool const created = creature->AIM_Create();
         ASSERT(created,
                "Creating the AI should never fail here!");
         (void)created;
@@ -432,6 +432,7 @@ class CreatureGameObjectScriptRegistrySwapHooks
         if (!creature->IsAlive())
             return;
 
+        creature->AI_InitializeAndEnable();
         creature->AI()->EnterEvadeMode();
 
         // Cast a dummy visual spell asynchronously here to signal