Sync login state on channel change (#323)

src/net/server/channel/handlers/PlayerLoggedinHandler.java

@@ -122,7 +122,6 @@ public final class PlayerLoggedinHandler extends AbstractMaplePacketHandler {
         c.setPlayer(player);
         c.setAccID(player.getAccountID());
         
-        int state = c.getLoginState();
         boolean allowLogin = true;
         
         World world = server.getWorld(c.getWorld());
@@ -158,12 +157,18 @@ public final class PlayerLoggedinHandler extends AbstractMaplePacketHandler {
         }
         */
 
+        c.lockClient(); // Sync this to prevent wrong login state for double channel changes
+        try {
+            int state = c.getLoginState();
             if (state != MapleClient.LOGIN_SERVER_TRANSITION || !allowLogin) {
                 c.setPlayer(null);
                 c.announce(MaplePacketCreator.getAfterLoginError(7));
                 return;
             }
             c.updateLoginState(MapleClient.LOGIN_LOGGEDIN);
+        } finally {
+            c.unlockClient();
+        }
         
         cserv.addPlayer(player);
         world.addPlayer(player);