Loading a parent scene then a child scene with ResourceLoader.load_interactive(...) causes "'res://Parent.tscn' is already being loaded. Cyclic reference?"

[31]

Godot version

3.3.2.stable

System information

Windows 10

Issue description

I set up three scenes:

• Parent.tscn
• Child.tscn inherits from Parent.tscn
• Spatial.tscn has a script that loads Parent, then loads Child:

	print(ResourceLoader.has_cached("res://Parent.tscn")) # False
	loaderP = ResourceLoader.load_interactive("res://Parent.tscn")
	loaderP.wait()
	print(ResourceLoader.has_cached("res://Parent.tscn")) # True
	loaderC = ResourceLoader.load_interactive("res://Child.tscn")
	loaderC.wait()

Obviously this isn't how you'd usually use this API, but it reproduces the error just fine. 😄 This was originally spotted in the wild with a typical use of .poll().

When I run with Spatial.tscn as the main scene, I get this output:

False
True
ERROR: Resource: 'res://Parent.tscn' is already being loaded. Cyclic reference?
   At: core/io/resource_loader.cpp:353
ERROR: poll: res://Child.tscn:3 - Parse Error: [ext_resource] referenced nonexistent resource at: res://Parent.tscn
   At: scene/resources/resource_format_text.cpp:440

It seems to me that when you use ResourceLoader.load_interactive, it doesn't end up calling ResourceLoader::_remove_from_loading_map, so it thinks that res://Parent.tscn is always being loaded from that point on.

It's the first ResourceLoader.load_interactive that seems to be the issue here--using load for the child still causes errors:

	loaderP = ResourceLoader.load_interactive("res://Parent.tscn")
	loaderP.wait()
	loaderC = ResourceLoader.load("res://Child.tscn")

Steps to reproduce

Run the main scene in the repro project or follow the steps in the description.

Minimal reproduction project

GodotLoadInteractiveInherit.zip