Core/Players: Fix possible (exploitable) data desynchronisation that would lead to repeating the same quest while already having received the rewards.

src/server/game/Entities/Player/Player.cpp

@@ -14960,17 +14960,24 @@ void Player::RewardQuest(Quest const *pQuest, uint32 reward, Object* questGiver,
             GetAchievementMgr().UpdateAchievementCriteria(ACHIEVEMENT_CRITERIA_TYPE_COMPLETE_DAILY_QUEST, quest_id);
             GetAchievementMgr().UpdateAchievementCriteria(ACHIEVEMENT_CRITERIA_TYPE_COMPLETE_DAILY_QUEST_DAILY, quest_id);
         }
-    } else if (pQuest->IsWeekly())
+    }
+    else if (pQuest->IsWeekly())
         SetWeeklyQuestStatus(quest_id);
 
     RemoveActiveQuest(quest_id);
     m_RewardedQuests.insert(quest_id);
     m_RewardedQuestsSave[quest_id] = true;
 
+    // StoreNewItem, mail reward, etc. save data directly to the database
+    // to prevent exploitable data desynchronisation we save the quest status to the database too
+    // (to prevent rewarding this quest another time while rewards were already given out)
+    SQLTransaction trans = SQLTransaction(NULL);
+    _SaveQuestStatus(trans);
+
     if (announce)
         SendQuestReward(pQuest, XP, questGiver);
 
-    // cast spells after mark quest complete (some spells have quest completed state reqyurements in spell_area data)
+    // cast spells after mark quest complete (some spells have quest completed state requirements in spell_area data)
     if (pQuest->GetRewSpellCast() > 0)
         CastSpell(this, pQuest->GetRewSpellCast(), true);
     else if (pQuest->GetRewSpell() > 0)
@@ -18629,6 +18636,10 @@ void Player::_SaveMail(SQLTransaction& trans)
 
 void Player::_SaveQuestStatus(SQLTransaction& trans)
 {
+    bool isTransaction = !trans.null();
+    if (!isTransaction)
+        trans = CharacterDatabase.BeginTransaction();
+
     QuestStatusSaveMap::iterator saveItr;
     QuestStatusMap::iterator statusItr;
 
@@ -18661,6 +18672,9 @@ void Player::_SaveQuestStatus(SQLTransaction& trans)
     }
 
     m_RewardedQuestsSave.clear();
+
+    if (!isTransaction)
+        CharacterDatabase.CommitTransaction(trans);
 }
 
 void Player::_SaveDailyQuestStatus(SQLTransaction& trans)