Error when assigning unnamed GDScript with exported variables

[anvilfolk]

Godot version

master

System information

W11

Issue description

This issue only happens in master, it does not occur in 4.0.2 so it is a recent regression.

When assigning a script without a class_name and with at least one @export variable to a node in the scene tree (and every time you save the script after), you will get an error: Class name cannot be empty.

The error appears to originate from the first line of Ref<Texture2D> EditorNode::get_class_icon(const String &p_class, const String &p_fallback):

ERR_FAIL_COND_V_MSG(p_class.is_empty(), nullptr, "Class name cannot be empty.");

Steps to reproduce

Create a script with

extends Node

@export var x : int

Then assign it to a node in your scene. The error will occur. Remove the @export and it will no longer occur. Add it again, and it will, every time you save the file.

Minimal reproduction project

N/A

[YuriSizov]

I guess it's a regression from #75472.

[anvilfolk]

I guess it's a regression from #75472.

That sounds right, from the stack trace I was looking at it seemed to specifically be related to _extension being null, so hopefully a simple check ought to fix it?

[anvilfolk]

So the error is in line 2779:

https://github.com/godotengine/godot/blob/master/editor/editor_inspector.cpp#L2761-L2782

script_name is empty because script_name = EditorNode::get_editor_data().script_class_get_name(scr->get_path()); returns empty since the path doesn't lead to a name. I guess here we want to default to something like GDScript or something?

I don't know enough about this part to be helpful :)

[anvilfolk]

I'm working on a fix for one :)

[capnm]

Here you get the same error even if you assign a value:

extends Node
@export var y := 1 :
	set(v):
		pass

Deselect / select the Node with the attached script:

ERROR: Class name cannot be empty.
at: get_class_icon (editor/editor_node.cpp:4471)
...

Note: Seems to be undocumented, no idea if it is still supported ...
how-to-use-godot-4-setget