Core/Spells: add correct checking for dispeling errors. Fixes spammable cleanse.

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

@@ -4113,6 +4113,45 @@ Aura* Unit::GetAuraOfRankedSpell(uint32 spellId, uint64 casterGUID, uint64 itemC
     return aurApp ? aurApp->GetBase() : NULL;
 }
 
+void Unit::GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList)
+{
+    // we should not be able to dispel diseases if the target is affected by unholy blight
+    if (dispelMask & (1 << DISPEL_DISEASE) && HasAura(50536))
+        dispelMask &= ~(1 << DISPEL_DISEASE);
+
+    AuraMap const& auras = GetOwnedAuras();
+    for (AuraMap::const_iterator itr = auras.begin(); itr != auras.end(); ++itr)
+    {
+        Aura* aura = itr->second;
+        AuraApplication * aurApp = aura->GetApplicationOfTarget(GetGUID());
+        if (!aurApp)
+            continue;
+
+        // don't try to remove passive auras
+        if (aura->IsPassive())
+            continue;
+
+        if (aura->GetSpellInfo()->GetDispelMask() & dispelMask)
+        {
+            if (aura->GetSpellInfo()->Dispel == DISPEL_MAGIC)
+            {
+                // do not remove positive auras if friendly target
+                //               negative auras if non-friendly target
+                if (aurApp->IsPositive() == IsFriendlyTo(caster))
+                    continue;
+            }
+
+            // The charges / stack amounts don't count towards the total number of auras that can be dispelled.
+            // Ie: A dispel on a target with 5 stacks of Winters Chill and a Polymorph has 1 / (1 + 1) -> 50% chance to dispell
+            // Polymorph instead of 1 / (5 + 1) -> 16%.
+            bool dispel_charges = aura->GetSpellInfo()->AttributesEx7 & SPELL_ATTR7_DISPEL_CHARGES;
+            uint8 charges = dispel_charges ? aura->GetCharges() : aura->GetStackAmount();
+            if (charges > 0)
+                dispelList.push_back(std::make_pair(aura, charges));
+        }
+    }
+}
+
 bool Unit::HasAuraEffect(uint32 spellId, uint8 effIndex, uint64 caster) const
 {
     for (AuraApplicationMap::const_iterator itr = m_appliedAuras.lower_bound(spellId); itr != m_appliedAuras.upper_bound(spellId); ++itr)

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

@@ -341,6 +341,7 @@ class Transport;
 class Vehicle;
 
 typedef std::list<Unit*> UnitList;
+typedef std::list< std::pair<Aura*, uint8> > DispelChargesList;
 
 struct SpellImmune
 {
@@ -1814,6 +1815,8 @@ class Unit : public WorldObject
         AuraApplication * GetAuraApplicationOfRankedSpell(uint32 spellId, uint64 casterGUID = 0, uint64 itemCasterGUID = 0, uint8 reqEffMask = 0, AuraApplication * except = NULL) const;
         Aura* GetAuraOfRankedSpell(uint32 spellId, uint64 casterGUID = 0, uint64 itemCasterGUID = 0, uint8 reqEffMask = 0) const;
 
+        void GetDispellableAuraList(Unit* caster, uint32 dispelMask, DispelChargesList& dispelList);
+
         bool HasAuraEffect(uint32 spellId, uint8 effIndex, uint64 caster = 0) const;
         uint32 GetAuraCount(uint32 spellId) const;
         bool HasAura(uint32 spellId, uint64 casterGUID = 0, uint64 itemCasterGUID = 0, uint8 reqEffMask = 0) const;

src/server/game/Spells/Spell.cpp

@@ -4938,6 +4938,24 @@ SpellCastResult Spell::CheckCast(bool strict)
     if (castResult != SPELL_CAST_OK)
         return castResult;
 
+    bool hasDispellableAura = false;
+    for (int i = 0; i < MAX_SPELL_EFFECTS; i++)
+        if (m_spellInfo->Effects[i].Effect == SPELL_EFFECT_DISPEL)
+            if (Unit* target = m_targets.GetUnitTarget())
+            {
+                DispelChargesList dispelList;
+                uint32 dispelMask = SpellInfo::GetDispelMask(DispelType(m_spellInfo->Effects[i].MiscValue));
+                target->GetDispellableAuraList(m_caster, dispelMask, dispelList);
+                if (!dispelList.empty())
+                {
+                    hasDispellableAura = true;
+                    break;
+                }
+            }            
+
+    if (!hasDispellableAura)
+        return SPELL_FAILED_NOTHING_TO_DISPEL;
+
     for (int i = 0; i < MAX_SPELL_EFFECTS; i++)
     {
         // for effects of spells that have only one target

src/server/game/Spells/SpellEffects.cpp

@@ -2536,7 +2536,6 @@ void Spell::EffectLearnSpell(SpellEffIndex effIndex)
 }
 
 typedef std::list< std::pair<uint32, uint64> > DispelList;
-typedef std::list< std::pair<Aura*, uint8> > DispelChargesList;
 void Spell::EffectDispel(SpellEffIndex effIndex)
 {
     if (effectHandleMode != SPELL_EFFECT_HANDLE_HIT_TARGET)
@@ -2545,48 +2544,12 @@ void Spell::EffectDispel(SpellEffIndex effIndex)
     if (!unitTarget)
         return;
 
-    DispelChargesList dispel_list;
-
     // Create dispel mask by dispel type
     uint32 dispel_type = m_spellInfo->Effects[effIndex].MiscValue;
     uint32 dispelMask  = SpellInfo::GetDispelMask(DispelType(dispel_type));
 
-    // we should not be able to dispel diseases if the target is affected by unholy blight
+    DispelChargesList dispel_list;
-    if (dispelMask & (1 << DISPEL_DISEASE) && unitTarget->HasAura(50536))
+    unitTarget->GetDispellableAuraList(m_caster, dispelMask, dispel_list);
-        dispelMask &= ~(1 << DISPEL_DISEASE);
-
-    Unit::AuraMap const& auras = unitTarget->GetOwnedAuras();
-    for (Unit::AuraMap::const_iterator itr = auras.begin(); itr != auras.end(); ++itr)
-    {
-        Aura* aura = itr->second;
-        AuraApplication * aurApp = aura->GetApplicationOfTarget(unitTarget->GetGUID());
-        if (!aurApp)
-            continue;
-
-        // don't try to remove passive auras
-        if (aura->IsPassive())
-            continue;
-
-        if (aura->GetSpellInfo()->GetDispelMask() & dispelMask)
-        {
-            if (aura->GetSpellInfo()->Dispel == DISPEL_MAGIC)
-            {
-                // do not remove positive auras if friendly target
-                //               negative auras if non-friendly target
-                if (aurApp->IsPositive() == unitTarget->IsFriendlyTo(m_caster))
-                    continue;
-            }
-
-            // The charges / stack amounts don't count towards the total number of auras that can be dispelled.
-            // Ie: A dispel on a target with 5 stacks of Winters Chill and a Polymorph has 1 / (1 + 1) -> 50% chance to dispell
-            // Polymorph instead of 1 / (5 + 1) -> 16%.
-            bool dispel_charges = aura->GetSpellInfo()->AttributesEx7 & SPELL_ATTR7_DISPEL_CHARGES;
-            uint8 charges = dispel_charges ? aura->GetCharges() : aura->GetStackAmount();
-            if (charges > 0)
-                dispel_list.push_back(std::make_pair(aura, charges));
-        }
-    }
-
     if (dispel_list.empty())
         return;