Core/AI: Finally move the "is creature engaged" flag to be a property of the creature AI, where it honestly always belonged. Fixes #17981 and #23602 for real this time.

(cherry picked from commit 0e7c66cb4c7ff7d44e232d0b50703a48605ffd24)

4 files changed, 14 insertions, 6 deletions

diff --git a/src/server/game/Entities/Creature/Creature.cpp b/src/server/game/Entities/Creature/Creature.cpp
index d966adbdd66..007664ec134 100644
--- a/src/server/game/Entities/Creature/Creature.cpp
+++ b/src/server/game/Entities/Creature/Creature.cpp
@@ -3397,6 +3397,13 @@ bool Creature::CanGiveExperience() const
         && !(GetCreatureTemplate()->flags_extra & CREATURE_FLAG_EXTRA_NO_XP_AT_KILL);
 }
 
+bool Creature::IsEngaged() const
+{
+    if (CreatureAI const* ai = AI())
+        return ai->IsEngaged();
+    return false;
+}
+
 void Creature::AtEngage(Unit* target)
 {
     Unit::AtEngage(target);
diff --git a/src/server/game/Entities/Creature/Creature.h b/src/server/game/Entities/Creature/Creature.h
index 119408a2f2e..a13dff72238 100644
--- a/src/server/game/Entities/Creature/Creature.h
+++ b/src/server/game/Entities/Creature/Creature.h
@@ -367,6 +367,7 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
 
         bool CanGiveExperience() const;
 
+        bool IsEngaged() const override;
         void AtEngage(Unit* target) override;
         void AtDisengage() override;
 
diff --git a/src/server/game/Entities/Unit/Unit.cpp b/src/server/game/Entities/Unit/Unit.cpp
index cb059be8d7a..2b1dbfdf74e 100644
--- a/src/server/game/Entities/Unit/Unit.cpp
+++ b/src/server/game/Entities/Unit/Unit.cpp
@@ -304,7 +304,7 @@ Unit::Unit(bool isWorldObject) :
     m_removedAurasCount(0), m_interruptMask(SpellAuraInterruptFlags::None), m_interruptMask2(SpellAuraInterruptFlags2::None),
     m_unitMovedByMe(nullptr), m_playerMovingMe(nullptr), m_charmer(nullptr), m_charmed(nullptr),
     i_motionMaster(new MotionMaster(this)), m_regenTimer(0), m_vehicle(nullptr),
-    m_vehicleKit(nullptr), m_unitTypeMask(UNIT_MASK_NONE), m_Diminishing(), m_isEngaged(false), m_combatManager(this),
+    m_vehicleKit(nullptr), m_unitTypeMask(UNIT_MASK_NONE), m_Diminishing(), m_combatManager(this),
     m_threatManager(this), m_aiLocked(false), _playHoverAnim(false), _aiAnimKitId(0), _movementAnimKitId(0), _meleeAnimKitId(0),
     _spellHistory(new SpellHistory(this))
 {
diff --git a/src/server/game/Entities/Unit/Unit.h b/src/server/game/Entities/Unit/Unit.h
index e42cce1e913..e88bcf953eb 100644
--- a/src/server/game/Entities/Unit/Unit.h
+++ b/src/server/game/Entities/Unit/Unit.h
@@ -1099,10 +1099,10 @@ class TC_GAME_API Unit : public WorldObject
 
         /// ====================== THREAT & COMBAT ====================
         bool CanHaveThreatList() const { return m_threatManager.CanHaveThreatList(); }
-        // This value can be different from IsInCombat:
+        // This value can be different from IsInCombat, for example:
         // - when a projectile spell is midair against a creature (combat on launch - threat+aggro on impact)
         // - when the creature has no targets left, but the AI has not yet ceased engaged logic
-        bool IsEngaged() const { return m_isEngaged; }
+        virtual bool IsEngaged() const { return IsInCombat(); }
         bool IsEngagedBy(Unit const* who) const { return CanHaveThreatList() ? IsThreatenedBy(who) : IsInCombatWith(who); }
         void EngageWithTarget(Unit* who); // Adds target to threat list if applicable, otherwise just sets combat state
         // Combat handling
@@ -1938,11 +1938,12 @@ class TC_GAME_API Unit : public WorldObject
         virtual void ProcessTerrainStatusUpdate(ZLiquidStatus status, Optional<LiquidData> const& liquidData);
         virtual void SetInWater(bool inWater);
 
+        // notifiers
         virtual void AtEnterCombat();
         virtual void AtExitCombat();
 
-        virtual void AtEngage(Unit* /*target*/) { m_isEngaged = true; }
-        virtual void AtDisengage() { m_isEngaged = false; }
+        virtual void AtEngage(Unit* /*target*/) {}
+        virtual void AtDisengage() {}
 
     private:
 
@@ -1971,7 +1972,6 @@ class TC_GAME_API Unit : public WorldObject
         Diminishing m_Diminishing;
 
         // Threat+combat management
-        bool m_isEngaged;
         friend class CombatManager;
         CombatManager m_combatManager;
         friend class ThreatManager;