Core/Vehicles:

- Grab correct npc entry from npc_spellclick_spells in case of player vehicle. Fixes DB errors added in my previous changeset
- Allow aura's with SPELL_AURA_CONTROL_VEHICLE to stack if there are enough free seats, even if spellIds are identical.
- Fix a possible infinite loop. Thanks to manuel for spotting

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

@@ -1251,7 +1251,7 @@ bool Creature::CreateFromProto(uint32 guidlow, uint32 Entry, uint32 vehId, uint3
     if (!vehId)
         vehId = cinfo->VehicleId;
 
-    if (vehId && !CreateVehicleKit(vehId))
+    if (vehId && !CreateVehicleKit(vehId, Entry))
         vehId = 0;
 
     Object::_Create(guidlow, Entry, vehId ? HIGHGUID_VEHICLE : HIGHGUID_UNIT);

src/server/game/Entities/Unit/Unit.cpp

@@ -11694,7 +11694,7 @@ void Unit::Mount(uint32 mount, uint32 VehicleId, uint32 creatureEntry)
 
         if (VehicleId)
         {
-            if (CreateVehicleKit(VehicleId))
+            if (CreateVehicleKit(VehicleId, creatureEntry))
             {
                 GetVehicleKit()->Reset();
 
@@ -11708,7 +11708,7 @@ void Unit::Mount(uint32 mount, uint32 VehicleId, uint32 creatureEntry)
                 plr->GetSession()->SendPacket(&data);
 
                 // mounts can also have accessories
-                GetVehicleKit()->InstallAllAccessories(creatureEntry);
+                GetVehicleKit()->InstallAllAccessories();
             }
         }
     }
@@ -15683,13 +15683,13 @@ void Unit::RestoreFaction()
     }
 }
 
-bool Unit::CreateVehicleKit(uint32 id)
+bool Unit::CreateVehicleKit(uint32 id, uint32 creatureEntry)
 {
     VehicleEntry const *vehInfo = sVehicleStore.LookupEntry(id);
     if (!vehInfo)
         return false;
 
-    m_vehicleKit = new Vehicle(this, vehInfo);
+    m_vehicleKit = new Vehicle(this, vehInfo, creatureEntry);
     m_updateFlag |= UPDATEFLAG_VEHICLE;
     m_unitTypeMask |= UNIT_MASK_VEHICLE;
     return true;
@@ -16459,7 +16459,7 @@ bool Unit::CheckPlayerCondition(Player* pPlayer)
 bool Unit::HandleSpellClick(Unit* clicker, int8 seatId)
 {
     bool success = false;
-    uint32 spellClickEntry = GetTypeId() == TYPEID_UNIT ? GetEntry() : GetUInt32Value(UNIT_FIELD_MOUNTDISPLAYID);
+    uint32 spellClickEntry = GetVehicleKit() ? GetVehicleKit()->m_creatureEntry : GetEntry();
     SpellClickInfoMapBounds clickPair = sObjectMgr->GetSpellClickInfoMapBounds(spellClickEntry);
     for (SpellClickInfoMap::const_iterator itr = clickPair.first; itr != clickPair.second; ++itr)
     {
@@ -16477,7 +16477,7 @@ bool Unit::HandleSpellClick(Unit* clicker, int8 seatId)
                 uint8 i = 0;
                 bool valid = false;
                 while (i < MAX_SPELL_EFFECTS && !valid)
-                    if (spellEntry->EffectApplyAuraName[i] == SPELL_AURA_CONTROL_VEHICLE)
+                    if (spellEntry->EffectApplyAuraName[i++] == SPELL_AURA_CONTROL_VEHICLE)
                         valid = true;
 
                 if (!valid)
@@ -16486,10 +16486,21 @@ bool Unit::HandleSpellClick(Unit* clicker, int8 seatId)
                     return false;
                 }
 
-                caster->CastCustomSpell(itr->second.spellId, SpellValueMod(SPELLVALUE_BASE_POINT0+i), seatId+1, target, true, NULL, NULL, origCasterGUID);
+                if (IsInMap(caster))
+                    caster->CastCustomSpell(itr->second.spellId, SpellValueMod(SPELLVALUE_BASE_POINT0+i), seatId+1, target, true, NULL, NULL, origCasterGUID);
+                else    // This can happen during Player::_LoadAuras
+                {
+                    int32 bp0 = seatId;
+                    Aura::TryCreate(spellEntry, this, clicker, &bp0, NULL, origCasterGUID);
+                }
             }
             else
-                caster->CastSpell(target, spellEntry, true, NULL, NULL, origCasterGUID);
+            {
+                if (IsInMap(caster))
+                    caster->CastSpell(target, spellEntry, true, NULL, NULL, origCasterGUID);
+                else
+                    Aura::TryCreate(spellEntry, this, clicker, NULL, NULL, origCasterGUID);
+            }
 
             success = true;
         }

src/server/game/Entities/Unit/Unit.h

@@ -2039,7 +2039,7 @@ class Unit : public WorldObject
         Unit *GetMisdirectionTarget() { return m_misdirectionTargetGUID ? GetUnit(*this, m_misdirectionTargetGUID) : NULL; }
 
         bool IsAIEnabled, NeedChangeAI;
-        bool CreateVehicleKit(uint32 id);
+        bool CreateVehicleKit(uint32 id, uint32 creatureEntry);
         void RemoveVehicleKit();
         Vehicle *GetVehicleKit()const { return m_vehicleKit; }
         Vehicle *GetVehicle()   const { return m_vehicle; }

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

@@ -27,7 +27,8 @@
 #include "CreatureAI.h"
 #include "ZoneScript.h"
 
-Vehicle::Vehicle(Unit *unit, VehicleEntry const *vehInfo) : me(unit), m_vehicleInfo(vehInfo), m_usableSeatNum(0), m_bonusHP(0)
+Vehicle::Vehicle(Unit *unit, VehicleEntry const *vehInfo, uint32 creatureEntry) 
+: me(unit), m_vehicleInfo(vehInfo), m_usableSeatNum(0), m_bonusHP(0), m_creatureEntry(creatureEntry)
 {
     for (uint32 i = 0; i < MAX_VEHICLE_SEATS; ++i)
     {
@@ -119,9 +120,11 @@ void Vehicle::Install()
         sScriptMgr->OnInstall(this);
 }
 
-void Vehicle::InstallAllAccessories(uint32 entry)
+void Vehicle::InstallAllAccessories()
 {
-    VehicleAccessoryList const* mVehicleList = sObjectMgr->GetVehicleAccessoryList(entry);
+    me->RemoveAurasByType(SPELL_AURA_CONTROL_VEHICLE);  // We might have aura's saved in the DB with now invalid casters - remove
+
+    VehicleAccessoryList const* mVehicleList = sObjectMgr->GetVehicleAccessoryList(m_creatureEntry);
     if (!mVehicleList)
         return;
 
@@ -167,7 +170,7 @@ void Vehicle::Reset()
     }
     else
     {
-        InstallAllAccessories(me->GetEntry());
+        InstallAllAccessories();
         if (m_usableSeatNum)
             me->SetFlag(UNIT_NPC_FLAGS, UNIT_NPC_FLAG_SPELLCLICK);
     }
@@ -528,3 +531,14 @@ SeatMap::iterator Vehicle::GetSeatIteratorForPassenger(Unit* passenger)
 
     return m_Seats.end();
 }
+
+uint8 Vehicle::GetAvailableSeatCount() const
+{
+    uint8 ret = 0;
+    SeatMap::const_iterator itr;
+    for (itr = m_Seats.begin(); itr != m_Seats.end(); ++itr)
+        if (!itr->second.passenger && (itr->second.seatInfo->CanEnterOrExit() || itr->second.seatInfo->IsUsableByOverride()))
+            ++ret;
+
+    return ret;
+}

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

@@ -113,14 +113,14 @@ class Vehicle
     friend class WorldSession;
 
     public:
-        explicit Vehicle(Unit *unit, VehicleEntry const *vehInfo);
+        explicit Vehicle(Unit *unit, VehicleEntry const *vehInfo, uint32 creatureEntry);
         virtual ~Vehicle();
 
         void Install();
         void Uninstall();
         void Reset();
         void Die();
-        void InstallAllAccessories(uint32 entry);
+        void InstallAllAccessories();
 
         Unit *GetBase() const { return me; }
         VehicleEntry const *GetVehicleInfo() const { return m_vehicleInfo; }
@@ -128,6 +128,7 @@ class Vehicle
         bool HasEmptySeat(int8 seatId) const;
         Unit *GetPassenger(int8 seatId) const;
         int8 GetNextEmptySeat(int8 seatId, bool next) const;
+        uint8 GetAvailableSeatCount() const;
 
         bool AddPassenger(Unit *passenger, int8 seatId = -1);
         void EjectPassenger(Unit* passenger, Unit* controller);
@@ -152,6 +153,7 @@ class Vehicle
         VehicleEntry const *m_vehicleInfo;
         uint32 m_usableSeatNum;         // Number of seats that match VehicleSeatEntry::UsableByPlayer, used for proper display flags
         uint32 m_bonusHP;
+        uint32 m_creatureEntry;         // Can be different than me->GetBase()->GetEntry() in case of players
 
         void InstallAccessory(uint32 entry, int8 seatId, bool minion, uint8 type, uint32 summonTime);
 };

src/server/game/Globals/ObjectMgr.cpp

@@ -790,12 +790,6 @@ void ObjectMgr::CheckCreatureTemplate(CreatureInfo const* cInfo)
     if (cInfo->rangeattacktime == 0)
         const_cast<CreatureInfo*>(cInfo)->rangeattacktime = BASE_ATTACK_TIME;
 
-    if (cInfo->npcflag & UNIT_NPC_FLAG_SPELLCLICK)
-    {
-        sLog->outErrorDb("Creature (Entry: %u) has dynamic flag UNIT_NPC_FLAG_SPELLCLICK (%u) set, it is expected to be set by code handling `npc_spellclick_spells` content.", cInfo->Entry, UNIT_NPC_FLAG_SPELLCLICK);
-        const_cast<CreatureInfo*>(cInfo)->npcflag &= ~UNIT_NPC_FLAG_SPELLCLICK;
-    }
-
     if ((cInfo->npcflag & UNIT_NPC_FLAG_TRAINER) && cInfo->trainer_type >= MAX_TRAINER_TYPE)
         sLog->outErrorDb("Creature (Entry: %u) has wrong trainer type %u.", cInfo->Entry, cInfo->trainer_type);
 

src/server/game/Spells/Auras/SpellAuraEffects.cpp

@@ -6594,7 +6594,7 @@ void AuraEffect::HandleAuraSetVehicle(AuraApplication const * aurApp, uint8 mode
 
     if (apply)
     {
-        if (!target->CreateVehicleKit(vehicleId))
+        if (!target->CreateVehicleKit(vehicleId, 0))
             return;
     }
     else if (target->GetVehicleKit())

src/server/game/Spells/SpellMgr.cpp

@@ -3177,6 +3177,34 @@ bool SpellMgr::CanAurasStack(Aura const *aura1, Aura const *aura2, bool sameCast
         }
     }
 
+    bool isVehicleAura1 = false;
+    bool isVehicleAura2 = false;
+    uint8 i = 0;
+    while (i < MAX_SPELL_EFFECTS && !(isVehicleAura1 && isVehicleAura2))
+    {
+        if (spellInfo_1->EffectApplyAuraName[i] == SPELL_AURA_CONTROL_VEHICLE)
+            isVehicleAura1 = true;
+        if (spellInfo_2->EffectApplyAuraName[i] == SPELL_AURA_CONTROL_VEHICLE)
+            isVehicleAura2 = true;
+
+        ++i;
+    }
+
+    if (isVehicleAura1 && isVehicleAura2)
+    {
+        Vehicle* veh = NULL;
+        if (aura1->GetOwner()->ToUnit())
+            veh = aura1->GetOwner()->ToUnit()->GetVehicleKit();
+
+        if (!veh)           // We should probably just let it stack. Vehicle system will prevent undefined behaviour later
+            return true;
+
+        if (!veh->GetAvailableSeatCount())
+            return false;   // No empty seat available
+
+        return true;        // Empty seat available (skip rest)
+    }
+
     uint32 spellId_1 = GetLastSpellInChain(spellInfo_1->Id);
     uint32 spellId_2 = GetLastSpellInChain(spellInfo_2->Id);
 

src/server/scripts/Northrend/FrozenHalls/PitOfSaron/boss_krickandick.cpp

@@ -162,7 +162,7 @@ class boss_ick : public CreatureScript
 
             void EnterCombat(Unit * /*who*/)
             {
-                _vehicle->InstallAllAccessories(me->GetEntry());
+                _vehicle->InstallAllAccessories();
 
                 if (Creature* krick = GetKrick())
                     DoScriptText(SAY_KRICK_AGGRO, krick);

src/server/scripts/Northrend/FrozenHalls/PitOfSaron/boss_scourgelord_tyrannus.cpp

@@ -301,7 +301,7 @@ class boss_rimefang : public CreatureScript
 
             void JustReachedHome()
             {
-                _vehicle->InstallAllAccessories(me->GetEntry());
+                _vehicle->InstallAllAccessories();
             }
 
             void DoAction(const int32 actionId)

src/server/scripts/Northrend/Ulduar/ulduar/boss_flame_leviathan.cpp

@@ -366,7 +366,7 @@ public:
         void SpellHit(Unit* /*caster*/, const SpellEntry* pSpell)
         {
             if (pSpell->Id == SPELL_START_THE_ENGINE)
-                vehicle->InstallAllAccessories(me->GetEntry());
+                vehicle->InstallAllAccessories();
 
             if (pSpell->Id == SPELL_ELECTROSHOCK)
                 me->InterruptSpell(CURRENT_CHANNELED_SPELL);