@export var n: Node3D breaks when changing the type of the set value in the scene editor

[mieldepoche]

Godot version

4.1.1

System information

linux

Issue description

As seen in this clip, if you change the type of the node, it invalidates the export. (printing its value in that state shows <Object#null>.

If the new node type is compatible, it should keep the value clean.
If the new node type is incompatible, it should display a warning somehow (maybe a node configuration warning?).

simplescreenrecorder-2023-10-07_08.20.47.mp4

Steps to reproduce

extends Node3D

@export var n: Node3D

func _ready() -> void:
    print(n)

fill out that variable in a scene and change the node type.

Minimal reproduction project

any

[jackwilsdon]

It looks like this is a duplicate of #78299, which should be fixed in 4.2 (#78300).

[Calinou]

Thanks for the report! Consolidating in #78299, which is fixed in 4.2.dev6.