IP Sanity check on Paper

Author: kyngs

Plugin/src/main/java/xyz/kyngs/librelogin/paper/PaperListeners.java

@@ -136,7 +136,12 @@ public void onPreLogin(AsyncPlayerPreLoginEvent event) {
 
     @EventHandler(priority = EventPriority.HIGHEST)
     public void chooseWorld(PlayerSpawnLocationEvent event) {
-        var world = chooseServer(event.getPlayer(), ipCache.getIfPresent(event.getPlayer()), readOnlyUserCache.getIfPresent(event.getPlayer().getUniqueId()));
+        var ip = ipCache.getIfPresent(event.getPlayer());
+        if (ip == null) {
+            event.getPlayer().kick(Component.text("Internal error, please try again later."));
+            return;
+        }
+        var world = chooseServer(event.getPlayer(), ip, readOnlyUserCache.getIfPresent(event.getPlayer().getUniqueId()));
         ipCache.invalidate(event.getPlayer());
         spawnLocationCache.invalidate(event.getPlayer());
         if (world.value() == null) {