Is there a way to stop Node.Any Instance types from being created automatically as children when added as a field to a Go extension class?

[ring-c]

When i change type to go-defined one, godot will add nodes from type to scene tree. Same if i create a new scene from go-type with exported nodes.

Is it possible to disable this behavior? Is it on go side or in godot?

[Splizard]

This behavior is on the Go side, can you share your use case? Previously, others have disabled this by making the field unexported but it sounds like you need the field to be exported, are you using this as a node reference?

[ring-c]

Yes i do use exported fields as a node reference. If i use a go-type as a root node of a scene (player, for example) and change type in godot to other type (better_player), than godot will add nodes from better_player to the scene.

If i change go-type to godot-type and back to same go-type - now i have to sets of nodes in the scene. Its making a mess and stops experiments.

Here is my GoBullet with is extends CharacterBody3D. I change its type to CharacterBody3D and back to GoBullet. The real collision is renamed with @, and new one is created in place with name Collision.
In code of GoBullet I have a Collision exported, but not Mesh

	Collision CollisionShape3D.Instance

[Splizard]

I'm thinking about introducing ID types to solve this, which would be typed Object Instance IDs for each class, which have a boolean on them when you retrieve them to signal whether they are still alive or not, this may also help with #130.

So for example, if I implement this, you would change the field to be this:

	Collision CollisionShape3D.ID

You can set it from the editor, or within the code:

	MyObject.Collision = SomeOtherObject.CollisionShape3D.ID()

Then when you want to borrow the Instance for a single frame:

	shape, stillAlive := MyObject.Collision.Instance()
	if stillAlive {
		// do something with collision shape
	} 

They would be more suitable to use as references, as the Instance family of types generally denotes Go ownership. The issue with Nodes, is they can generally be freed at any time and as you've previously discovered, this leads to memory issues.

[ring-c]

Sounds good. Maybe return a pointer, so stillAlive check will be more go way?

if shape != nil

[Splizard]

@ring-c I've pushed this, it's using the v, ok := ... pattern to avoid an allocation.

[ring-c]

Tested on UI buttons - works for me.

[ring-c]

@Splizard
Hi. Testing a little bit more, seems i use it wrong?
Example, scene root:

type Test struct {
	Node3D.Extension[Test]

	Waypoints Node3D.ID
}

func (n *Test) Ready() {
	wp, ok := n.Waypoints.Instance()
	if !ok {
		println("Waypoints not OK")
		return
	}
}

In godot i create a scene with root of Test and Waypoints does not auto-created, good!
In godot i create node3D child with name Waypoints.
Running the code, Ready is always return Waypoints not OK. And n.Waypoints is seems equal 0.
I am doing something wrong?

[Splizard]

Right, IDs don't refer to children automatically, you would need to assign them on Ready, or in the editor.

type Test struct {
	Node3D.Extension[Test]

	Waypoints Node3D.ID
}

func (n *Test) Ready() {
	n.Waypoints = n.AsNode().GetNode("Waypoints").ID()
}

[ring-c]

Can we do it automatically? Would be cool.

[Splizard]

Hmm, why not use an Instance?

[ring-c]

Well, this discussion started with problem, why not :)
If in this example i create scene with Instance - scene will be created with Waypoints. It not as bad as change type scenario, where Waypoints will be duplicated.