Core/Spawning: Actually check spawn group state before processing a respawn. It feels like that is something that should've been noticed at some point.

Port From (https://github.com/TrinityCore/TrinityCore/commit/5c80f5073493a3d31fd4b463891727beb6fe7eb1)

Source/Game/Entities/Creature/Creature.cs

@@ -443,15 +443,20 @@ namespace Game.Entities
             {
                 case DeathState.JustRespawned:
                 case DeathState.JustDied:
-                    Log.outError(LogFilter.Unit, "Creature ({0}) in wrong state: {1}", GetGUID().ToString(), m_deathState);
+                    Log.outError(LogFilter.Unit, $"Creature ({GetGUID()}) in wrong state: {m_deathState}");
                     break;
                 case DeathState.Dead:
                 {
+                    if (!m_respawnCompatibilityMode)
+                    {
+                        Log.outError(LogFilter.Unit, $"Creature (GUID: {GetGUID().GetCounter()} Entry: {GetEntry()}) in wrong state: DEAD (3)");
+                        break;
+                    }
                     long now = GameTime.GetGameTime();
                     if (m_respawnTime <= now)
                     {
-                            // First check if there are any scripts that object to us respawning
+                        // Delay respawn if spawn group is not active
-                            if (!Global.ScriptMgr.CanSpawn(GetSpawnId(), GetEntry(), GetCreatureData(), GetMap()))
+                        if (m_creatureData != null && !GetMap().IsSpawnGroupActive(m_creatureData.spawnGroupData.groupId))
                         {
                             m_respawnTime = now + RandomHelper.URand(4, 7);
                             break; // Will be rechecked on next Update call after delay expires
@@ -3119,7 +3124,7 @@ namespace Game.Entities
             CreatureData data = Global.ObjectMgr.GetCreatureData(spawnId);
             if (data == null)
             {
-                Log.outError(LogFilter.Sql, "Creature (GUID: {0}) not found in table `creature`, can't load. ", spawnId);
+                Log.outError(LogFilter.Sql, $"Creature (SpawnID: {spawnId}) not found in table `creature`, can't load.");
                 return false;
             }
 
@@ -3128,12 +3133,6 @@ namespace Game.Entities
             m_creatureData = data;
             m_respawnradius = data.spawndist;
             m_respawnDelay = (uint)data.spawntimesecs;
-            // Is the creature script objecting to us spawning? If yes, delay by a little bit (then re-check in ::Update)
-            if (!m_respawnCompatibilityMode && m_respawnTime == 0 && !Global.ScriptMgr.CanSpawn(spawnId, data.Id, data, map))
-            {
-                SaveRespawnTime(RandomHelper.URand(4, 7));
-                return false;
-            }
 
             if (!Create(map.GenerateLowGuid(HighGuid.Creature), map, data.Id, data.spawnPoint, data, 0, !m_respawnCompatibilityMode))
                 return false;
@@ -3146,8 +3145,11 @@ namespace Game.Entities
             m_respawnTime = GetMap().GetCreatureRespawnTime(m_spawnId);
 
             // Is the creature script objecting to us spawning? If yes, delay by a little bit (then re-check in ::Update)
-            if (m_respawnCompatibilityMode && m_respawnTime == 0 && !Global.ScriptMgr.CanSpawn(spawnId, GetEntry(), GetCreatureData(), map))
+            if (m_respawnTime == 0 && !map.IsSpawnGroupActive(data.spawnGroupData.groupId))
+            {
+                Cypher.Assert(m_respawnCompatibilityMode, $"Creature (SpawnID {spawnId}) trying to load in inactive spawn group {data.spawnGroupData.name}.");
                 m_respawnTime = GameTime.GetGameTime() + RandomHelper.URand(4, 7);
+            }
 
             if (m_respawnTime != 0)                          // respawn on UpdateLoadCreatureFromDB
             {

Source/Game/Maps/Instances/InstanceScript.cs

@@ -249,7 +249,7 @@ namespace Game.Maps
                 if (doSpawn)
                     instance.SpawnGroupSpawn(groupId, instance);
                 else // otherwise, set it as inactive so it no longer respawns (but don't despawn it)
-                    instance.SetSpawnGroupActive(groupId, false);
+                    instance.SetSpawnGroupInactive(groupId);
             }
         }
 

Source/Game/Maps/Map.cs

@@ -2329,8 +2329,18 @@ namespace Game.Maps
 
         bool CheckRespawn(RespawnInfo info)
         {
+            SpawnData data = Global.ObjectMgr.GetSpawnData(info.type, info.spawnId);
+            Cypher.Assert(data != null, $"Invalid respawn info with type {info.type}, spawnID {info.spawnId} in respawn queue.");
+
+            // First, check if this creature's spawn group is inactive
+            if (!IsSpawnGroupActive(data.spawnGroupData.groupId))
+            {
+                info.respawnTime = 0;
+                return false;
+            }
+
             uint poolId = info.spawnId != 0 ? Global.PoolMgr.IsPartOfAPool(info.type, info.spawnId) : 0;
-            // First, check if there's already an instance of this object that would block the respawn
+            // Next, check if there's already an instance of this object that would block the respawn
             // Only do this for unpooled spawns
             if (poolId == 0)
             {
@@ -2340,14 +2350,7 @@ namespace Game.Maps
                     case SpawnObjectType.Creature:
                     {
                         // escort check for creatures only (if the world config boolean is set)
-                            bool isEscort = false;
+                        bool isEscort = WorldConfig.GetBoolValue(WorldCfg.RespawnDynamicEscortNpc) && data.spawnGroupData.flags.HasFlag(SpawnGroupFlags.EscortQuestNpc);
-                            if (WorldConfig.GetBoolValue(WorldCfg.RespawnDynamicEscortNpc) && info.type == SpawnObjectType.Creature)
-                            {
-                                CreatureData cdata = Global.ObjectMgr.GetCreatureData(info.spawnId);
-                                if (cdata != null)
-                                    if (cdata.spawnGroupData.flags.HasAnyFlag(SpawnGroupFlags.EscortQuestNpc))
-                                        isEscort = true;
-                            }
 
                         var range = _creatureBySpawnIdStore.LookupByKey(info.spawnId);
                         foreach (var creature in range)
@@ -2411,15 +2414,7 @@ namespace Game.Maps
                 return false;
             }
 
-            // if we're a creature, see if the script objects to us spawning
+            // everything ok, let's spawn
-            if (info.type == SpawnObjectType.Creature)
-            {
-                if (!Global.ScriptMgr.CanSpawn(info.spawnId, info.entry, Global.ObjectMgr.GetCreatureData(info.spawnId), this))
-                { // if a script blocks our respawn, schedule next check in a little bit
-                    info.respawnTime = GameTime.GetGameTime() + RandomHelper.URand(4, 7);
-                    return false;
-                }
-            }
             return true;
         }
 
@@ -2822,6 +2817,10 @@ namespace Game.Maps
                 _toggledSpawnGroupIds.Remove(groupId);
         }
 
+        // Disable the spawn group, which prevents any creatures in the group from respawning until re-enabled
+        // This will not affect any already-present creatures in the group
+        public void SetSpawnGroupInactive(uint groupId) { SetSpawnGroupActive(groupId, false); }
+
         public bool IsSpawnGroupActive(uint groupId)
         {
             SpawnGroupTemplateData data = GetSpawnGroupData(groupId);
@@ -5050,7 +5049,7 @@ namespace Game.Maps
             // @todo Not sure about checking player level: already done in HandleAreaTriggerOpcode
             // GMs still can teleport player in instance.
             // Is it needed?
-            lock(_mapLock)
+            lock (_mapLock)
             {
                 // Dungeon only code
                 if (IsDungeon())

Source/Game/Maps/ObjectGridLoader.cs

@@ -110,14 +110,6 @@ namespace Game.Maps
                                 continue;
                             }
                         }
-
-                        // If script is blocking spawn, don't spawn but queue for a re-check in a little bit
-                        if (!group.flags.HasFlag(SpawnGroupFlags.CompatibilityMode) && !Global.ScriptMgr.CanSpawn(guid, cdata.Id, cdata, map))
-                        {
-                            map.SaveRespawnTime(SpawnObjectType.Creature, guid, cdata.Id, GameTime.GetGameTime() + RandomHelper.URand(4, 7), map.GetZoneId(PhasingHandler.EmptyPhaseShift, cdata.spawnPoint), GridDefines.ComputeGridCoord(cdata.spawnPoint.GetPositionX(), cdata.spawnPoint.GetPositionY()).GetId(), false);
-                            obj.Dispose();
-                            continue;
-                        }
                     }
                     else if (obj.IsTypeId(TypeId.GameObject))
                     {

Source/Game/Scripting/CoreScripts.cs

@@ -333,9 +333,6 @@ namespace Game.Scripting
 
         public override bool IsDatabaseBound() { return true; }
 
-        // Called when the creature tries to spawn. Return false to block spawn and re-evaluate on next tick.
-        public virtual bool CanSpawn(ulong spawnId, uint entry, CreatureTemplate baseTemplate, CreatureTemplate actTemplate, CreatureData cData, Map map) { return true; }
-
         // Called when a CreatureAI object is needed for the creature.
         public virtual CreatureAI GetAI(Creature creature) { return null; }
     }

Source/Game/Scripting/ScriptManager.cs

@@ -681,44 +681,6 @@ namespace Game.Scripting
             return RunScriptRet<ItemScript>(tmpscript => tmpscript.OnCastItemCombatSpell(player, victim, spellInfo, item), item.GetScriptId());
         }
 
-        //CreatureScript
-        public bool CanSpawn(ulong spawnId, uint entry, CreatureData cData, Map map)
-        {
-            Cypher.Assert(map != null);
-
-            CreatureTemplate baseTemplate = Global.ObjectMgr.GetCreatureTemplate(entry);
-            Cypher.Assert(baseTemplate != null);
-
-            // find out which template we'd be using
-            CreatureTemplate actTemplate = null;
-            DifficultyRecord difficultyEntry = CliDB.DifficultyStorage.LookupByKey(map.GetDifficultyID());
-            while (actTemplate == null && difficultyEntry != null)
-            {
-                int idx = CreatureTemplate.DifficultyIDToDifficultyEntryIndex(difficultyEntry.Id);
-                if (idx == -1)
-                    break;
-
-                if (baseTemplate.DifficultyEntry[idx] != 0)
-                {
-                    actTemplate = Global.ObjectMgr.GetCreatureTemplate(baseTemplate.DifficultyEntry[idx]);
-                    break;
-                }
-
-                if (difficultyEntry.FallbackDifficultyID == 0)
-                    break;
-
-                difficultyEntry = CliDB.DifficultyStorage.LookupByKey(difficultyEntry.FallbackDifficultyID);
-            }
-
-            if (actTemplate == null)
-                actTemplate = baseTemplate;
-
-            uint scriptId = baseTemplate.ScriptID;
-            if (cData != null && cData.ScriptId != 0)
-                scriptId = cData.ScriptId;
-
-            return RunScriptRet<CreatureScript, bool>(p => p.CanSpawn(spawnId, entry, baseTemplate, actTemplate, cData, map), scriptId, true);
-        }
         public CreatureAI GetCreatureAI(Creature creature)
         {
             Cypher.Assert(creature != null);