fix(eventbus): Prevent dangling pointer crash during bot cleanup

During bot destruction, the Player object may be destroyed before
the BotAI destructor runs, causing _bot to become a dangling pointer.
When UnsubscribeFromEventBuses() tries to access _bot->GetGUID(),
it crashes with ACCESS_VIOLATION at GenericEventBus.h line 277.

Fix:
- Add _cachedBotGuid member to BotAI, initialized at construction
- Add UnsubscribeByGuid() method to GenericEventBus template
- Update UnsubscribeFromEventBuses() to use cached GUID directly
  via EventBus<T>::instance()->UnsubscribeByGuid(_cachedBotGuid)

This ensures safe cleanup even when Player is already destroyed.

Co-Authored-By: Claude Opus 4.5 <[email protected]>
Signed-off-by: luis <[email protected]>

src/modules/Playerbot/AI/BotAI.cpp

@@ -124,7 +124,10 @@ std::vector<uint32> BotAI::GetCompletableQuestIds() const
 // CONSTRUCTOR / DESTRUCTOR
 // ============================================================================
 
-BotAI::BotAI(Player* bot, bool instanceOnlyMode) : _bot(bot), _instanceOnlyMode(instanceOnlyMode)
+BotAI::BotAI(Player* bot, bool instanceOnlyMode)
+    : _bot(bot)
+    , _cachedBotGuid(bot ? bot->GetGUID() : ObjectGuid::Empty)  // Cache for safe destructor cleanup
+    , _instanceOnlyMode(instanceOnlyMode)
 {
     // Initialize performance tracking
     _performanceMetrics.lastUpdate = std::chrono::steady_clock::now();

src/modules/Playerbot/AI/BotAI.h

@@ -321,6 +321,7 @@ public:
 
     Player* GetBot() const { return _bot; }
     ObjectGuid GetBotGuid() const { return _bot ? _bot->GetGUID() : ObjectGuid::Empty; }
+    ObjectGuid GetCachedBotGuid() const { return _cachedBotGuid; }  // Safe during destructor
 
     // ========================================================================
     // LIFECYCLE MANAGEMENT - Two-Phase AddToWorld Pattern
@@ -957,6 +958,7 @@ protected:
 protected:
     // Core components
     Player* _bot;
+    ObjectGuid _cachedBotGuid;  // Cached at construction for safe destructor cleanup
     BotAIState _aiState = BotAIState::SOLO;
     ObjectGuid _currentTarget;
 

src/modules/Playerbot/AI/BotAI_EventHandlers.cpp

@@ -23,6 +23,7 @@
 
 #include "BotAI.h"
 #include "GameTime.h"
+#include "Core/Events/GenericEventBus.h"
 #include "Group/GroupEventBus.h"
 #include "Combat/CombatEventBus.h"
 #include "Cooldown/CooldownEventBus.h"
@@ -92,28 +93,29 @@ void BotAI::SubscribeToEventBuses()
 
 void BotAI::UnsubscribeFromEventBuses()
 {
-    if (!_bot)
+    // CRITICAL FIX: Use cached GUID instead of _bot pointer during destructor
+    // The Player object may already be destroyed when BotAI destructor runs,
+    // making _bot a dangling pointer. Using the cached GUID is safe.
+    if (_cachedBotGuid.IsEmpty())
         return;
 
-    // CRITICAL: Unsubscribe from all event buses to prevent dangling pointers
-    GroupEventBus::instance()->Unsubscribe(this);
-    CombatEventBus::instance()->Unsubscribe(this);
-    CooldownEventBus::instance()->Unsubscribe(this);
-    AuraEventBus::instance()->Unsubscribe(this);
-    LootEventBus::instance()->Unsubscribe(this);
-    QuestEventBus::instance()->Unsubscribe(this);
-    ResourceEventBus::instance()->Unsubscribe(this);
-    SocialEventBus::instance()->Unsubscribe(this);
-    AuctionEventBus::instance()->Unsubscribe(this);
-    NPCEventBus::instance()->Unsubscribe(this);
-    InstanceEventBus::instance()->Unsubscribe(this);
-    ProfessionEventBus::instance()->Unsubscribe(this);
+    // CRITICAL: Unsubscribe from all event buses using GUID (safe during destructor)
+    // Call the underlying template directly with the new UnsubscribeByGuid method
+    EventBus<GroupEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<CombatEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<CooldownEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<AuraEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<LootEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<QuestEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<ResourceEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<SocialEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<AuctionEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<NPCEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<InstanceEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
+    EventBus<ProfessionEvent>::instance()->UnsubscribeByGuid(_cachedBotGuid);
 
-    // CRITICAL: Use GetGUID().ToString() instead of GetName() during destructor
-    // GetName() may access invalid memory during bot destruction
-    // This prevents ACCESS_VIOLATION crash at BotAI_EventHandlers.cpp line 110
     TC_LOG_DEBUG("playerbot.events", "Bot unsubscribed from all event buses (GUID: {})",
-        _bot->GetGUID().ToString());
+        _cachedBotGuid.ToString());
 }
 
 // ============================================================================

src/modules/Playerbot/Core/Events/GenericEventBus.h

@@ -285,6 +285,31 @@ public:
             subscriberGuid.ToString());
     }
 
+    /**
+     * @brief Unsubscribe a bot by GUID (safe for use during destructor)
+     *
+     * This overload is specifically designed for use during BotAI destruction,
+     * when the Player object may already be destroyed but we have a cached GUID.
+     *
+     * @param botGuid The cached GUID of the bot to unsubscribe
+     *
+     * Thread Safety: Yes (mutex-protected)
+     * Performance: O(1) average case (hash map erase)
+     */
+    void UnsubscribeByGuid(ObjectGuid const& botGuid)
+    {
+        if (botGuid.IsEmpty())
+            return;
+
+        std::lock_guard lock(_subscriptionMutex);
+
+        _subscriptions.erase(botGuid);
+        _subscriberPointers.erase(botGuid);
+
+        TC_LOG_DEBUG("playerbot.events", "EventBus: Bot {} unsubscribed by GUID from all events",
+            botGuid.ToString());
+    }
+
     /**
      * @brief Unsubscribe a bot from specific event types
      *