Debugging

When a script doesn’t do what you expect, don’t guess: make it tell you.

Print a value

let me: Entity = $entity.get()
$debug.print_line("created on {}", [$entity.get_name(me)], false)

Each {} is filled with the next value in the list. Anything can go in: numbers, text, vectors, handles.

Tag your messages

The log is busy. Start every message with your script’s name in brackets, so you can find yours:

$debug.print_line("[welcome_mat] greeted {} so far", [3], false)

Warnings and errors

Use the level that matches: print_line for tracing, print_warning when something’s off but the script can carry on, print_error when it can’t.

let name: string = "partner_pad"
let target: Entity = $entity.get_child_named(name, true, $entity.get())
if !target {
  $debug.print_warning("[teleport_pad] no entity named {}", [name], false)
  return
}

Printing a warning where a lookup fails, and then returning, turns a silent “nothing happens” into a message that says exactly what’s missing.

Which machine said it?

Your script runs on the server and on every client, so each message may appear several times. Say which copy it came from:

let side: string = if $net.is_server() { "server" } else { "client" }
$debug.print_line("[press_counter] {} sees count {}", [side, 4], false)

Is the event even running?

Put a print as the first line of the event. No message means the engine never called it. Check the spelling of the event’s name, that it’s event export fn, and that the component is on an entity the game loads.

event export fn trigger_overlapped(other, unused) {
  $debug.print_line("[my_script] overlap from {}", [other], false)
}

Printing every frame

A print in tick runs every frame and floods the log. Print on changes, or behind a condition, and remove tracing when you’re done.

When the compiler complains

Every compiler message has an id like V0302. Look it up in Compiler messages for what it means and how to fix it.