Prevent loading faraway chunks (#4370)

* Prevent loading faraway chunks

* docs

Core/src/main/java/com/plotsquared/core/command/MainCommand.java

@@ -268,6 +268,7 @@ public class MainCommand extends Command {
                     tp = true;
                 } else {
                     player.sendMessage(TranslatableCaption.of("border.denied"));
+                    return CompletableFuture.completedFuture(false);
                 }
                 // Trim command
                 args = Arrays.copyOfRange(args, 1, args.length);

Core/src/main/java/com/plotsquared/core/plot/Plot.java

@@ -2574,6 +2574,12 @@ public class Plot {
      */
     public void teleportPlayer(final PlotPlayer<?> player, TeleportCause cause, Consumer<Boolean> resultConsumer) {
         Plot plot = this.getBasePlot(false);
+        if (!WorldUtil.isValidLocation(plot.getBottomAbs())) {
+            // prevent from teleporting into unsafe regions
+            player.sendMessage(TranslatableCaption.of("border.denied"));
+            resultConsumer.accept(false);
+            return;
+        }
 
         PlayerTeleportToPlotEvent event = this.eventDispatcher.callTeleport(player, player.getLocation(), plot, cause);
         if (event.getEventResult() == Result.DENY) {

Core/src/main/java/com/plotsquared/core/util/WorldUtil.java

@@ -62,6 +62,15 @@ import java.util.zip.ZipOutputStream;
 
 public abstract class WorldUtil {
 
+    /**
+     * {@return whether the given location is valid in the world}
+     * @param location the location to check
+     * @since TODO
+     */
+    public static boolean isValidLocation(Location location) {
+        return Math.abs(location.getX()) < 30000000 && Math.abs(location.getZ()) < 30000000;
+    }
+
     /**
      * Set the biome in a region
      *