fix: add null-check for brush in traceMask (#2160)

* fix: add null-check for brush in traceMask
 - Fixes #2149

* Switch to print from printError

Co-authored-by: Alexander Brandes <mc.cache@web.de>

---------

Co-authored-by: Alexander Brandes <mc.cache@web.de>

worldedit-core/src/main/java/com/sk89q/worldedit/command/ToolUtilCommands.java

@@ -169,9 +169,14 @@ public class ToolUtilCommands {
     public void traceMask(
             Player player, LocalSession session,
             @Arg(desc = "The trace mask to set", def = "")
-                    Mask maskOpt
+            Mask maskOpt
     ) throws WorldEditException {
-        session.getBrushTool(player, false).setTraceMask(maskOpt);
+        BrushTool brushTool = session.getBrushTool(player, false);
+        if (brushTool == null) {
+            player.print(Caption.of("worldedit.brush.none.equipped"));
+            return;
+        }
+        brushTool.setTraceMask(maskOpt);
         if (maskOpt == null) {
             player.print(Caption.of("worldedit.tool.tracemask.disabled"));
         } else {

worldedit-core/src/main/resources/lang/strings.json

@@ -283,6 +283,7 @@
   "worldedit.brush.butcher.equip": "Butcher brush equipped ({0}).",
   "worldedit.brush.operation.equip": "Set brush to {0}.",
   "worldedit.brush.none.equip": "Brush unbound from your current item.",
+  "worldedit.brush.none.equipped": "You have no brush bound to your current item. Try /brush sphere for a basic brush.",
   "worldedit.setbiome.changed": "Biomes were changed in {0} columns. You may have to rejoin your game (or close and reopen your world) to see a change.",
   "worldedit.setbiome.not-locatable": "Command sender must be present in the world to use the -p flag.",
   "worldedit.drawsel.disabled": "Server CUI disabled.",