Godot 4 Migration Guide

Overview

Tween

export

When to Use This Skill

• Use when porting a Godot 3 project to Godot 4.
• Use when encountering syntax errors after upgrading.
• Use when replacing deprecated nodes (like

  Tween

  node vs

  create_tween

  ).
• Use when updating

  export

  variables to

  @export

  annotations.

Key Changes

1. Annotations (

@

)

@

• export var x

  ->

  @export var x

• onready var y

  ->

  @onready var y

• tool

  ->

  @tool

  (at top of file)

2. Setters and Getters

var health setget set_health, get_health

func set_health(value):
    health = value

var health: int:
    set(value):
        health = value
        emit_signal("health_changed", health)
    get:
        return health

3. Tween System

Tween

create_tween()

$Tween.interpolate_property(...)
$Tween.start()

var tween = create_tween()
tween.tween_property($Sprite, "position", Vector2(100, 100), 1.0)
tween.parallel().tween_property($Sprite, "modulate:a", 0.0, 1.0)

4. Signal Connections

connect("pressed", self, "_on_pressed")

pressed.connect(_on_pressed)

Examples

Example 1: Typed Arrays

# Godot 3
var enemies = []

# Godot 4
var enemies: Array[Node] = []

func _ready():
    for child in get_children():
        if child is Enemy:
            enemies.append(child)

Example 2: Awaiting Signals (Coroutines)

yield

await

yield(get_tree().create_timer(1.0), "timeout")

await get_tree().create_timer(1.0).timeout

Best Practices

• ✅ Do: Use

  @export_range

  ,

  @export_file

  , etc., for better inspector UI.
• ✅ Do: Type all variables (

  var x: int

  ) for performance gains in GDScript 2.0.
• ✅ Do: Use

  super()

  to call parent methods instead of

  .function_name()

  .
• ❌ Don't: Use string names for signals (

  emit_signal("name")

  ) if you can use the signal object (

  name.emit()

  ).

Troubleshooting

Tween

SceneTreeTween

create_tween()

var tween = create_tween()