Deserializing a nested object fails with a nil dereference in object_serializer.gd

[caprica]

I think I have missed something too obvious for me to see, or that I'm misunderstanding the capabilities of this library.

I have an object with a nested object. This should be able to serialise/deserialise, right?

class Outer:
	var first: String
	var inner: Inner

	func _init(first: String, inner: Inner):
		self.first = first
		self.inner = inner

	func _get_constructor_args():
		return [first, inner]

class Inner:
	var apples: int
	var oranges: int

	func _init(apples: int, oranges: int):
		self.apples = apples
		self.oranges = oranges

	func _get_constructor_args():
		return [apples, oranges]

func test_outer_inner():
	ObjectSerializer.register_script("Outer", Outer)
	ObjectSerializer.register_script("Inner", Inner)

	var test = Outer.new("hello", Inner.new(123, 456))

	var ser = BinarySerializer.serialize_var(test)
	var bytes = var_to_bytes(ser)

	var des = bytes_to_var(bytes)
	var result = BinarySerializer.deserialize_var(des)
	
	print("Result", result)

Yields this error:

Report:
line 132: Godot Runtime Error !
	'at: _ScriptRegistryEntry.deserialize (res://addons/godot_object_serializer/object_serializer.gd:132)'
Error: 'Invalid call. Nonexistent function 'has_method' in base 'Nil'.'

object_serializer.gd:

		var instance: Variant
		if value.has(ObjectSerializer.args_field):
			instance = script_type.new.callv(value[ObjectSerializer.args_field])         <---- this returns null
		else:
			instance = script_type.new()

		var excluded_properties: Array[String] = []
		if instance.has_method("_get_excluded_properties"):             <------ error at this line, instance is null
			excluded_properties = instance._get_excluded_properties()

What am I doing wrong?

[caprica]

In the debugger, when the Outer instance is being deserialised, I looked at the args being passed to the script new instance call.

The first arg is the string "hello" as expected.

The second arg is shown in the debugger/inspector as an EncodedObjectAsID instance, not the Inner instance I was expecting.

Is this the problem?

[caprica]

If I change it all to not use constructors, it works.

It's not ideal, but I can live with not using constructors in these objects.