Godot 4.2 is unable to preload resources that DO exist.

[Bloxxel64]

Tested versions

This issue did not occur before i upgraded to 4.2.

System information

Linux Mint on GD 4.2 stable

Issue description

When attempting to instantiate a scene through code, you first have to preload it, but for some reason godot is saying that it does not exist:

extends Node2D


# Called when the node enters the scene tree for the first time.
func _ready():
	var roomnum = randi() % 3
	
	var rooms = [preload("res://scenes/rooms/emptyrooms/Empty1.tscn"), preload("res://scenes/rooms/emptyrooms/Empty1.tscn"), preload("res://scenes/rooms/emptyrooms/Empty3.tscn")]
	
	var dospawn = rooms[roomnum].instantiate()
	add_child(dospawn)
	print(roomnum)

Steps to reproduce

Download the project, open it, and debug run it.

Minimal reproduction project (MRP)

project.zip

[rsubtil]

The error message is really cryptic and unhelpful. It seems the issue is due to a loading cycle. On base.tscn you load the inst.gd script with loads that same scene:

extends Node2D


# Called when the node enters the scene tree for the first time.
func _ready():
	var baller = preload("res://base.tscn")
	add_child(baller)

If you comment/remove that _ready function, the scene loads normally again.

This issue did not occur before i upgraded to 4.2.

Did you upgrade from any 4.x version, or earlier from 3.x?

[Bloxxel64]

The error message is really cryptic and unhelpful. It seems the issue is due to a loading cycle. On base.tscn you load the inst.gd script with loads that same scene:

im sorry im not really sure what details i need to provide.

extends Node2D


# Called when the node enters the scene tree for the first time.
func _ready():
	var baller = preload("res://base.tscn")
	add_child(baller)

well im a dumbass, the code is incorrect.

If you comment/remove that _ready function, the scene loads normally again.

ill... try that...

[rsubtil]

im sorry im not really sure what details i need to provide.

I meant that the error Godot gives is not clear; it wasn't about your report 🙂

I don't know if your scenario is supposed to work or not, but since you mentioned that it has happened since you ported this code to 4.2, this might be a regression. What was the previous Godot version you were using?

[Bloxxel64]

im sorry im not really sure what details i need to provide.

I meant that the error Godot gives is not clear; it wasn't about your report 🙂

I don't know if your scenario is supposed to work or not, but since you mentioned that it has happened since you ported this code to 4.2, this might be a regression. What was the previous Godot version you were using?

the project is only from 4.1, but i only got errors when i upgraded to 4.2, incidentally. sometimes godot will say the scenes are corrupted when i try to open them for some reason

[francescarpi]

Hi.

I've got the same issue on v4.2.stable.official [46dc277]

With the "preload" line, an error raises when Godot starting. Line 140 of "bug.tscn" references the "bug.gd" script.

If I comment the line, error message disappear.

[francescarpi]

Changing preload for load works well. Seen in this other reported issue

#85081 (comment)

[WhalesState]

Using the MRP, I have found that you are preloading base.tscn inside base.tscn and adding it as a child without instantiating it.

from the variable name i think you just wants to add the other scene ball.tscn to the base.tscn as a child, so this code should work fine without raising any issues.

Update the inst.gd script and reload the project from Project menu.

func _ready():
	var baller = preload("res://ball.tscn").instantiate()
	add_child(baller)

If I'm wrong and you want to preload the same scene inside itself, then you can try other methods like self.duplicate() for example, since the packed scene is already loaded.

Edit: Using var baller = self.duplicate() and adding it as child will raise this error inst.gd:7 @ _ready(): Can't add child 'Node2D' to itself.

I'm thinking if this should be considered as an issue, peloading Scene(A) which is using Script(A) inside Script(A) and adding it as a child to Scene(A), it will be an infinity loop. Maybe the compiler should raise an error when preloading a scene which is using the same script or preloading the same script inside itself, to prevent crashing the editor when using tool scripts.