fix(Core/Vehicles): Prevent accessory double-install and respawn orphans (#25499)

Co-authored-by: blinkysc <blinkysc@users.noreply.github.com>

src/server/game/Entities/Creature/Creature.cpp

@@ -1113,9 +1113,6 @@ bool Creature::AIM_Initialize(CreatureAI* ai)
     IsAIEnabled = true;
     i_AI->InitializeAI();
 
-    // Xinef: Initialize vehicle if it is not summoned!
-    if (GetVehicleKit() && m_spawnId)
-        GetVehicleKit()->Reset();
     return true;
 }
 
@@ -2052,6 +2049,10 @@ void Creature::Respawn(bool force)
 
             if (getDeathState() == DeathState::Dead)
             {
+                // TempSummons (no m_spawnId) shouldn't be resurrected here; TempSummon::Update UnSummons them on the next tick once deathState is Dead.
+                if (!m_spawnId && !force)
+                    return;
+
                 if (m_spawnId)
                 {
                     GetMap()->RemoveCreatureRespawnTime(m_spawnId);

src/server/game/Entities/Vehicle/Vehicle.cpp

@@ -29,7 +29,8 @@
 #include <algorithm>
 
 Vehicle::Vehicle(Unit* unit, VehicleEntry const* vehInfo, uint32 creatureEntry) :
-    _me(unit), _vehicleInfo(vehInfo), _usableSeatNum(0), _creatureEntry(creatureEntry), _status(STATUS_NONE)
+    _me(unit), _vehicleInfo(vehInfo), _usableSeatNum(0), _creatureEntry(creatureEntry), _status(STATUS_NONE),
+    _accessoriesInstalled(false)
 {
     for (uint32 i = 0; i < MAX_VEHICLE_SEATS; ++i)
     {
@@ -87,8 +88,16 @@ void Vehicle::Install()
 
 void Vehicle::InstallAllAccessories(bool evading)
 {
-    if (GetBase()->IsPlayer() || !evading)
-        RemoveAllPassengers();   // We might have aura's saved in the DB with now invalid casters - remove
+    // Clear stale control-vehicle auras only on the first non-evade reset;
+    // a re-Reset would otherwise eject a just-seated passenger and, for
+    // accessories, fire a spurious SMART_EVENT_PASSENGER_REMOVED.
+    if (GetBase()->IsPlayer() || (!evading && !_accessoriesInstalled))
+        RemoveAllPassengers();
+
+    // Mark the initial reset as done even if this vehicle has no accessory
+    // list, so subsequent Resets don't eject passengers on vehicles without
+    // accessories (e.g. WG demolisher/catapult).
+    _accessoriesInstalled = true;
 
     VehicleAccessoryList const* accessories = sObjectMgr->GetVehicleAccessoryList(this);
     if (!accessories)
@@ -111,6 +120,7 @@ void Vehicle::Uninstall()
     _status = STATUS_UNINSTALLING;
     LOG_DEBUG("vehicles", "Vehicle::Uninstall {}", _me->GetGUID().ToString());
     RemoveAllPassengers();
+    _accessoriesInstalled = false;
 
     if (_me && _me->IsCreature())
     {

src/server/game/Entities/Vehicle/Vehicle.h

@@ -96,6 +96,7 @@ private:
     uint32 _usableSeatNum;         // Number of seats that match VehicleSeatEntry::UsableByPlayer, used for proper display flags
     uint32 _creatureEntry;         // Can be different than me->GetBase()->GetEntry() in case of players
     Status _status;
+    bool _accessoriesInstalled;
 };
 
 class VehicleDespawnEvent : public BasicEvent

src/server/game/Grids/GridObjectLoader.cpp

@@ -24,6 +24,7 @@
 #include "GridNotifiers.h"
 #include "ObjectMgr.h"
 #include "Transport.h"
+#include "Vehicle.h"
 
 template <class T>
 void GridObjectLoader::AddObjectHelper(Map* map, T* obj)
@@ -53,6 +54,10 @@ void GridObjectLoader::LoadCreatures(CellGuidSet const& guid_set, Map* map)
 
         AddObjectHelper<Creature>(map, obj);
 
+        // Grid load bypasses Map::AddToMap, so seat accessories here.
+        if (Vehicle* vehicle = obj->GetVehicleKit())
+            vehicle->Reset();
+
         if (!obj->IsMoveInLineOfSightDisabled() && obj->GetDefaultMovementType() == IDLE_MOTION_TYPE && !obj->isNeedNotify(NOTIFY_VISIBILITY_CHANGED | NOTIFY_AI_RELOCATION))
         {
             if (obj->IsAlive() && !obj->HasUnitState(UNIT_STATE_SIGHTLESS) && obj->HasReactState(REACT_AGGRESSIVE) && !obj->IsImmuneToNPC())

src/server/game/Maps/Map.cpp

@@ -346,8 +346,7 @@ bool Map::AddToMap(T* obj, bool checkTransport)
     //also, trigger needs to cast spell, if not update, cannot see visual
     obj->UpdateObjectVisibility(true);
 
-    // Xinef: little hack for vehicles, accessories have to be added after visibility update so they wont fall off the vehicle, moved from Creature::AIM_Initialize
-    // Initialize vehicle, this is done only for summoned npcs, DB creatures are handled by grid loaders
+    // Post-visibility so accessories seat after the vehicle's create packet reaches clients.
     if (obj->IsCreature())
         if (Vehicle* vehicle = obj->ToCreature()->GetVehicleKit())
             vehicle->Reset();