Core/Spells: Protect against stack overflows in spell override handling

Port From (https://github.com/TrinityCore/TrinityCore/commit/723e638a84d2aebe8a41fc39ba94f1a04138797e)

Source/Game/Entities/Player/Player.Spells.cs

@@ -274,20 +274,23 @@ namespace Game.Entities
             return false;
         }
 
-        public override SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag)
+        public override SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
         {
             var overrides = m_overrideSpells.LookupByKey(spellInfo.Id);
             if (!overrides.Empty())
             {
                 foreach (uint spellId in overrides)
                 {
-                    SpellInfo newInfo = Global.SpellMgr.GetSpellInfo(spellId, GetMap().GetDifficultyID());
-                    if (newInfo != null)
-                        return GetCastSpellInfo(newInfo, triggerFlag);
+                    if (context.AddSpell(spellId))
+                    {
+                        SpellInfo newInfo = Global.SpellMgr.GetSpellInfo(spellId, GetMap().GetDifficultyID());
+                        if (newInfo != null)
+                            return GetCastSpellInfo(newInfo, triggerFlag, context);
+                    }
                 }
             }
 
-            return base.GetCastSpellInfo(spellInfo, triggerFlag);
+            return base.GetCastSpellInfo(spellInfo, triggerFlag, context);
         }
 
         public void SetOverrideSpellsId(uint overrideSpellsId) { SetUpdateFieldValue(m_values.ModifyValue(m_activePlayerData).ModifyValue(m_activePlayerData.OverrideSpellsID), overrideSpellsId); }
@@ -3879,7 +3882,8 @@ namespace Game.Entities
             }
 
             // Check possible spell cast overrides
-            spellInfo = castingUnit.GetCastSpellInfo(spellInfo, triggerFlag);
+            GetCastSpellInfoContext overrideContext = new();
+            spellInfo = castingUnit.GetCastSpellInfo(spellInfo, triggerFlag, overrideContext);
             if (spellInfo.IsPassive())
             {
                 CancelPendingCastRequest();

Source/Game/Entities/Unit/Unit.Spells.cs

@@ -944,14 +944,14 @@ namespace Game.Entities
             spell.Finish(result);
         }
 
-        public virtual SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag)
+        public virtual SpellInfo GetCastSpellInfo(SpellInfo spellInfo, TriggerCastFlags triggerFlag, GetCastSpellInfoContext context)
         {
             SpellInfo findMatchingAuraEffectIn(AuraType type)
             {
                 foreach (AuraEffect auraEffect in GetAuraEffectsByType(type))
                 {
                     bool matches = auraEffect.GetMiscValue() != 0 ? auraEffect.GetMiscValue() == spellInfo.Id : auraEffect.IsAffectingSpell(spellInfo);
-                    if (matches)
+                    if (matches && context.AddSpell((uint)auraEffect.GetAmount()))
                     {
                         SpellInfo info = Global.SpellMgr.GetSpellInfo((uint)auraEffect.GetAmount(), GetMap().GetDifficultyID());
                         if (info != null)
@@ -979,14 +979,14 @@ namespace Game.Entities
             if (newInfo != null)
             {
                 triggerFlag &= ~TriggerCastFlags.IgnoreCastTime;
-                return GetCastSpellInfo(newInfo, triggerFlag);
+                return GetCastSpellInfo(newInfo, triggerFlag, context);
             }
 
             newInfo = findMatchingAuraEffectIn(AuraType.OverrideActionbarSpellsTriggered);
             if (newInfo != null)
             {
                 triggerFlag |= TriggerCastFlags.IgnoreCastTime;
-                return GetCastSpellInfo(newInfo, triggerFlag);
+                return GetCastSpellInfo(newInfo, triggerFlag, context);
             }
 
             return spellInfo;
@@ -4602,4 +4602,26 @@ namespace Game.Entities
         public void SetVisibleAuraUpdate(AuraApplication aurApp) { m_visibleAurasToUpdate.Add(aurApp); }
         public void RemoveVisibleAuraUpdate(AuraApplication aurApp) { m_visibleAurasToUpdate.Remove(aurApp); }
     }
+
+    public class GetCastSpellInfoContext
+    {
+        uint[] VisitedSpells = new uint[5];
+
+        public bool AddSpell(uint spellId)
+        {
+            if (VisitedSpells.Contains(spellId))
+                return false; // already exists
+
+            for (int i = 0; i < VisitedSpells.Length; ++i)
+            {
+                if (VisitedSpells[i] != 0u)
+                    continue;
+
+                VisitedSpells[i] = spellId;
+                return true;
+            }
+
+            return false;
+        }
+    }
 }