Core/Spells: Prevent deterrance from parrying spells that require the attacker to be behind the hunter, like Shred or Ambush.

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

@@ -2402,14 +2402,22 @@ SpellMissInfo Unit::MeleeSpellHitResult(Unit* victim, SpellInfo const* spell)
     }
 
     // Check for attack from behind
-    if (!victim->HasInArc(M_PI, this) && !victim->HasAuraType(SPELL_AURA_IGNORE_HIT_DIRECTION))
+    if (!victim->HasInArc(M_PI, this))
     {
-        // Can`t dodge from behind in PvP (but its possible in PvE)
-        if (victim->GetTypeId() == TYPEID_PLAYER)
-            canDodge = false;
-        // Can`t parry or block
-        canParry = false;
-        canBlock = false;
+        if (!victim->HasAuraType(SPELL_AURA_IGNORE_HIT_DIRECTION))
+        {
+            // Can`t dodge from behind in PvP (but its possible in PvE)
+            if (victim->GetTypeId() == TYPEID_PLAYER)
+                canDodge = false;
+            // Can`t parry or block
+            canParry = false;
+            canBlock = false;
+        }
+        else // Only deterrence as of 3.3.5
+        {
+            if (spell->AttributesCu & SPELL_ATTR0_CU_REQ_CASTER_BEHIND_TARGET)
+                canParry = false;
+        }
     }
     // Check creatures flags_extra for disable parry
     if (victim->GetTypeId() == TYPEID_UNIT)