Typed Array constructor has no clear documentation about how it should be used

[Gnumaru]

Godot version

v4.0.3.stable.official [5222a99]

System information

Windows 10

Issue description

There is one (and only one, at least that is exposed to gdscript) array constructor meant to creating typed arrays. This constructor takes as first parameter a base array for copying it's elements from. But the way the constructor should be used could be better documented with examples for creating typed arrays from native types and custom types, and these could have examples for scripts with and without class_name and also for inner classes.

Steps to reproduce

Create a script with the code bellow and run it. It will yield the same error in any of the attempts to use the typed array. constructor. The correct usage has been clarified in the comments bellow but my struggle to find how to do it is at least an example of the poor experience other users could avoid if there where a couple of examples in the docs.

extends Node
class MyClass: pass # inner class to create a type array of it
func _ready()->void:
	var a:Array = [MyClass.new()] # untyped array to copy into the typed one
	var b:Array[MyClass] # array typed with a class name

	# NONE of the methods bellow work. all of them will yield the runtime error "trying to assign an array of type "Array[MyClass]" to a variable of type "Array[MyClass]".
	# the stack trace is
#	E 0:00:03:0344   DELETEME.gd:12 @ _ready(): Attempted to assign an object of type 'RefCounted' into a TypedArray, which does not inherit from 'MyClass'.
#  <C++ Error>    Condition "!ClassDB::is_parent_class(object->get_class_name(), class_name)" is true. Returning: false
#  <C++ Source>   core/variant/container_type_validate.h:129 @ validate_object()
#  <Stack Trace>  DELETEME.gd:12 @ _ready()
	b = Array(a, TYPE_OBJECT, &'MyClass', null)
	b = Array(a, TYPE_OBJECT, &'RefCounted', null)
	b = Array(a, TYPE_OBJECT, &'Object', null)
	b = Array([]+a, TYPE_OBJECT, &'MyClass', null)
	b = Array(a.duplicate(), TYPE_OBJECT, &'MyClass', null)
	b = Array([]+a.duplicate(), TYPE_OBJECT, &'MyClass', null)
	b = Array(a.slice(0), TYPE_OBJECT, &'MyClass', null)
	b = Array(a.map(func(p):return p), TYPE_OBJECT, &'MyClass', null)
	b = Array(a.filter(func(p):return true), TYPE_OBJECT, &'MyClass', null)

	# this is the only method that works
	b = []
	for i in a: b.push_back(i)

Minimal reproduction project

N/A

[AThousandShips]

You need to put the script as the fourth argument I think, see documentation

[Gnumaru]

It doesn't work either. Regardless of using "self" or "self.MyClass"

[AThousandShips]

That's not the script though, it's a class, try get_script

[Gnumaru]

I'm sorry, I was too hasty. but it doesn't work either

[AThousandShips]

Try with RefCounted as the third argument

[Gnumaru]

nope

[Gnumaru]

but it does work with MyClass which is the expected

[AThousandShips]

Then no bug, though ambiguous as MyClass isn't a script

[Gnumaru]

The docs are still not much clear about this. Should I close this and open a bug in godot-docs? or just leave this here?

[AThousandShips]

Leave here, the class reference is handled here

[dalexeev]

Use

Array(a, TYPE_OBJECT, &"RefCounted", MyClass)

[AThousandShips]

Already resolved above :)

[dalexeev]

If/when #71336 is merged, this should become less verbose and confusing:

Array[MyClass](a)