1 files changed, 27 insertions, 1 deletions

diff --git a/src/server/game/Maps/Map.cpp b/src/server/game/Maps/Map.cpp
index 476d98afc66..5c908ba445f 100644
--- a/src/server/game/Maps/Map.cpp
+++ b/src/server/game/Maps/Map.cpp
@@ -2369,7 +2369,7 @@ bool InstanceMap::CanEnter(Player *player)
     if (player->GetMapRef().getTarget() == this)
     {
         sLog.outError("InstanceMap::CanEnter - player %s(%u) already in map %d,%d,%d!", player->GetName(), player->GetGUIDLow(), GetId(), GetInstanceId(), GetSpawnMode());
-        assert(false);
+        //assert(false);
         return false;
     }
 
@@ -2395,6 +2395,32 @@ bool InstanceMap::CanEnter(Player *player)
         return false;
     }
 
+    // cannot enter if instance is in use by another party/soloer that have a
+    // permanent save in the same instance id
+
+    PlayerList const &playerList = GetPlayers();
+    Player *firstInsidePlayer = NULL;
+
+    if (!playerList.isEmpty())
+        for (PlayerList::const_iterator i = playerList.begin(); i != playerList.end(); ++i)
+            if (Player *iPlayer = i->getSource())
+            {
+                if (iPlayer->isGameMaster()) // bypass GMs
+                    continue;
+                if (!player->GetGroup()) // player has not group and there is someone inside, deny entry
+                {
+                    player->SendTransferAborted(GetId(), TRANSFER_ABORT_MAX_PLAYERS);
+                    return false;
+                }
+                // player inside instance has no group or his groups is different to entering player's one, deny entry
+                if (!iPlayer->GetGroup() || iPlayer->GetGroup() != player->GetGroup() )
+                {
+                    player->SendTransferAborted(GetId(), TRANSFER_ABORT_MAX_PLAYERS);
+                    return false;
+                }
+                break;
+            }
+
     return Map::CanEnter(player);
 }