Godot 4 Migration

2. Setters and Getters

Properties now define setters/getters inline.

Godot 3:

var health setget set_health, get_health

func set_health(value):
    health = value

Godot 4:

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

3. Tween System

The Tween node is deprecated. Use create_tween() in code.

Godot 3:

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

Godot 4:

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

String-based connections are discouraged. Use callables.

Godot 3:

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

Godot 4:

pressed.connect(_on_pressed)

Examples

Example 1: Typed Arrays

GDScript 2.0 supports typed arrays for better performance and type safety.

# 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 is replaced by await.

Godot 3:

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

Godot 4:

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

Problem: "Identifier 'Tween' is not a valid type." Solution: Tween is now SceneTreeTween or just an object returned by create_tween(). You rarely type it explicitly, just use var tween = create_tween().

Limitations

• Use this skill only when the task clearly matches the scope described above.
• Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
• Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.