Core/Spell: SpellAura Redux (#22794)

* typo and correction

* spell aura no longer shared between targets

_spellAura isolated

* SPELL_AURA_CONTROL_VEHICLE is not strictly single target spell

Steam Tank Control and Wyrmrest Commander

units can reseat themselves again

* Rename 9999_99_99_99_world.sql to 2019_03_08_00_world.sql

(cherry picked from commit ec3cb05d7fbc5cef60d000af910dc39dd3af92bf)

1 files changed, 15 insertions, 14 deletions

diff --git a/src/server/game/Spells/Spell.cpp b/src/server/game/Spells/Spell.cpp
index 2444044c29c..0c4b991ef23 100644
--- a/src/server/game/Spells/Spell.cpp
+++ b/src/server/game/Spells/Spell.cpp
@@ -2671,7 +2671,9 @@ void Spell::TargetInfo::DoDamageAndTriggers(Spell* spell)
             spell->m_caster->ToPlayer()->UpdatePvP(true);
     }
 
+    spell->_spellAura = HitAura;
     spell->CallScriptAfterHitHandlers();
+    spell->_spellAura = nullptr;
 }
 
 void Spell::GOTargetInfo::DoTargetSpellHit(Spell* spell, SpellEffectInfo const& spellEffectInfo)
@@ -2841,8 +2843,7 @@ void Spell::DoSpellEffectHit(Unit* unit, SpellEffectInfo const& spellEffectInfo,
         {
             bool refresh = false;
 
-            // delayed spells with multiple targets need to create a new aura object, otherwise we'll access a deleted aura
-            if (!_spellAura || (m_spellInfo->HasHitDelay() && !m_spellInfo->IsChanneled()))
+            if (!hitInfo.HitAura)
             {
                 bool const resetPeriodicTimer = !(_triggeredCastFlags & TRIGGERED_DONT_RESET_PERIODIC_TIMER);
                 uint32 const allAuraEffectMask = Aura::BuildEffectMaskForOwner(m_spellInfo, MAX_EFFECT_MASK, unit);
@@ -2858,22 +2859,22 @@ void Spell::DoSpellEffectHit(Unit* unit, SpellEffectInfo const& spellEffectInfo,
 
                 if (Aura* aura = Aura::TryRefreshStackOrCreate(createInfo))
                 {
-                    _spellAura = aura->ToUnitAura();
+                    hitInfo.HitAura = aura->ToUnitAura();
 
                     // Set aura stack amount to desired value
                     if (m_spellValue->AuraStackAmount > 1)
                     {
                         if (!refresh)
-                            _spellAura->SetStackAmount(m_spellValue->AuraStackAmount);
+                            hitInfo.HitAura->SetStackAmount(m_spellValue->AuraStackAmount);
                         else
-                            _spellAura->ModStackAmount(m_spellValue->AuraStackAmount);
+                            hitInfo.HitAura->ModStackAmount(m_spellValue->AuraStackAmount);
                     }
 
-                    _spellAura->SetDiminishGroup(hitInfo.DRGroup);
+                    hitInfo.HitAura->SetDiminishGroup(hitInfo.DRGroup);
 
                     if (!m_spellValue->Duration)
                     {
-                        hitInfo.AuraDuration = caster->ModSpellDuration(m_spellInfo, unit, hitInfo.AuraDuration, hitInfo.Positive, _spellAura->GetEffectMask());
+                        hitInfo.AuraDuration = caster->ModSpellDuration(m_spellInfo, unit, hitInfo.AuraDuration, hitInfo.Positive, hitInfo.HitAura->GetEffectMask());
 
                         if (hitInfo.AuraDuration > 0)
                         {
@@ -2886,7 +2887,7 @@ void Spell::DoSpellEffectHit(Unit* unit, SpellEffectInfo const& spellEffectInfo,
                             {
                                 int32 origDuration = hitInfo.AuraDuration;
                                 hitInfo.AuraDuration = 0;
-                                for (AuraEffect const* auraEff : _spellAura->GetAuraEffects())
+                                for (AuraEffect const* auraEff : hitInfo.HitAura->GetAuraEffects())
                                     if (auraEff)
                                         if (int32 period = auraEff->GetPeriod())  // period is hastened by UNIT_MOD_CAST_SPEED
                                             hitInfo.AuraDuration = std::max(std::max(origDuration / period, 1) * period, hitInfo.AuraDuration);
@@ -2900,21 +2901,21 @@ void Spell::DoSpellEffectHit(Unit* unit, SpellEffectInfo const& spellEffectInfo,
                     else
                         hitInfo.AuraDuration = m_spellValue->Duration.get();
 
-                    if (hitInfo.AuraDuration != _spellAura->GetMaxDuration())
+                    if (hitInfo.AuraDuration != hitInfo.HitAura->GetMaxDuration())
                     {
-                        _spellAura->SetMaxDuration(hitInfo.AuraDuration);
-                        _spellAura->SetDuration(hitInfo.AuraDuration);
+                        hitInfo.HitAura->SetMaxDuration(hitInfo.AuraDuration);
+                        hitInfo.HitAura->SetDuration(hitInfo.AuraDuration);
                     }
                 }
             }
             else
-                _spellAura->AddStaticApplication(unit, aura_effmask);
-
-            hitInfo.HitAura = _spellAura;
+                hitInfo.HitAura->AddStaticApplication(unit, aura_effmask);
         }
     }
 
+    _spellAura = hitInfo.HitAura;
     HandleEffects(unit, nullptr, nullptr, spellEffectInfo, SPELL_EFFECT_HANDLE_HIT_TARGET);
+    _spellAura = nullptr;
 }
 
 void Spell::DoTriggersOnSpellHit(Unit* unit, uint32 effMask)