Core/Spells: Use Unit::IsValidAttack/AssistTarget functions to validate spell explicit targets.

src/server/game/Spells/Spell.cpp

@@ -4781,7 +4781,7 @@ SpellCastResult Spell::CheckCast(bool strict)
     // those spells may have incorrect target entries or not filled at all (for example 15332)
     // such spells when learned are not targeting anyone using targeting system, they should apply directly to caster instead
     // also, such casts shouldn't be sent to client
-    if (!(((m_spellInfo->Attributes & SPELL_ATTR0_PASSIVE) && !m_targets.GetUnitTarget()) || m_targets.GetUnitTarget() == m_caster))
+    if (!((m_spellInfo->Attributes & SPELL_ATTR0_PASSIVE) && (!m_targets.GetUnitTarget() || m_targets.GetUnitTarget() == m_caster)))
     {
         // Check explicit target for m_originalCaster - todo: get rid of such workarounds
         SpellCastResult castResult = m_spellInfo->CheckExplicitTarget(m_originalCaster ? m_originalCaster : m_caster, m_targets.GetObjectTarget(), m_targets.GetItemTarget());
@@ -4818,14 +4818,14 @@ SpellCastResult Spell::CheckCast(bool strict)
                         return SPELL_FAILED_TARGET_AURASTATE;
             }
         }
+    }
 
     // check pet presence
     for (int j = 0; j < MAX_SPELL_EFFECTS; ++j)
     {
         if (m_spellInfo->Effects[j].TargetA.GetTarget() == TARGET_UNIT_PET)
         {
-                target = m_caster->GetGuardianPet();
+            if (!m_caster->GetGuardianPet())
-                if (!target)
             {
                 if (m_triggeredByAuraSpell)              // not report pet not existence for triggered spells
                     return SPELL_FAILED_DONT_REPORT;
@@ -4835,7 +4835,6 @@ SpellCastResult Spell::CheckCast(bool strict)
             break;
         }
     }
-    }
 
     // Spell casted only on battleground
     if ((m_spellInfo->AttributesEx3 & SPELL_ATTR3_BATTLEGROUND) &&  m_caster->GetTypeId() == TYPEID_PLAYER)

src/server/game/Spells/SpellInfo.cpp

@@ -1634,7 +1634,7 @@ SpellCastResult SpellInfo::CheckTarget(Unit const* caster, Unit const* target, b
     if (!(AttributesEx6 & SPELL_ATTR6_CAN_TARGET_INVISIBLE) && !caster->canSeeOrDetect(target, implicit))
         return SPELL_FAILED_BAD_TARGETS;
 
-    // TODO: more research
+    // checked in Unit::IsValidAttack/AssistTarget, shouldn't be checked for ENTRY targets
     //if (!(AttributesEx6 & SPELL_ATTR6_CAN_TARGET_UNTARGETABLE) && target->HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_NOT_SELECTABLE))
     //    return SPELL_FAILED_BAD_TARGETS;
 
@@ -1648,14 +1648,6 @@ SpellCastResult SpellInfo::CheckTarget(Unit const* caster, Unit const* target, b
             return SPELL_FAILED_BAD_TARGETS;
     }
 
-    // check UNIT_FLAG_NON_ATTACKABLE flag - a player can cast spells on his pet (or other controlled unit) though in any state
-    if (!IsPositive() && target != caster && target->GetCharmerOrOwnerGUID() != caster->GetGUID())
-    {
-        // any unattackable target skipped
-        if (target->HasFlag(UNIT_FIELD_FLAGS, UNIT_FLAG_NON_ATTACKABLE))
-            return SPELL_FAILED_BAD_TARGETS;
-    }
-
     // check GM mode and GM invisibility - only for player casts (npc casts are controlled by AI) and negative spells
     if (target != caster && (caster->IsControlledByPlayer() || !IsPositive()) && target->GetTypeId() == TYPEID_PLAYER)
     {
@@ -1738,16 +1730,12 @@ SpellCastResult SpellInfo::CheckExplicitTarget(Unit const* caster, WorldObject c
         if (neededTargets & (TARGET_FLAG_UNIT_ENEMY | TARGET_FLAG_UNIT_ALLY | TARGET_FLAG_UNIT_RAID | TARGET_FLAG_UNIT_PARTY | TARGET_FLAG_UNIT_MINIPET | TARGET_FLAG_UNIT_PASSENGER))
         {
             if (neededTargets & TARGET_FLAG_UNIT_ENEMY)
-                if (!caster->IsFriendlyTo(unitTarget))
+                if (caster->_IsValidAttackTarget(unitTarget, this))
                     return SPELL_CAST_OK;
-            if (neededTargets & TARGET_FLAG_UNIT_ALLY)
+            if (neededTargets & TARGET_FLAG_UNIT_ALLY
-                if (caster->IsFriendlyTo(unitTarget))
+                || (neededTargets & TARGET_FLAG_UNIT_PARTY && caster->IsInPartyWith(unitTarget))
-                    return SPELL_CAST_OK;
+                || (neededTargets & TARGET_FLAG_UNIT_RAID && caster->IsInRaidWith(unitTarget)))
-            if (neededTargets & TARGET_FLAG_UNIT_PARTY)
+                    if (caster->_IsValidAssistTarget(unitTarget, this))
-                if (caster->IsInPartyWith(unitTarget))
-                    return SPELL_CAST_OK;
-            if (neededTargets & TARGET_FLAG_UNIT_RAID)
-                if (caster->IsInRaidWith(unitTarget))
                         return SPELL_CAST_OK;
             if (neededTargets & TARGET_FLAG_UNIT_MINIPET)
                 if (unitTarget->GetGUID() == caster->GetCritterGUID())