Cannot change texture property of a Sprite2D Node using animation tracks in GDScript

[codyroberts]

Tested versions

Reproducible in v4.2.1.stable.official.b09f793f5

Attempted to reproduce in v3.5.3.stable.mono.official but not confident I could create an equivalent example, however in what I did attempt the feature still did not work.

System information

Windows 10

Issue description

When attempting to create an animation entirely in GDScript using an existing image, the texture cannot be animated. Attempting to animate the texture appears to cause the Sprite2D to have no texture, being invisible upon debugging.

Steps to reproduce

1. Create a Node2D node
2. Add a Sprite2D child node, and assign it a texture using the Inspector GUI
3. Set up an animation on the Node2D node to change the texture of the Sprite2D node similar to the provided sample script below

extends Node2D

# Create the animation player and library
@onready var animation_player := AnimationPlayer.new()
@onready var animation_library := AnimationLibrary.new()

# Called when the node enters the scene tree for the first time.
func _ready():
	
	# Add the animation player as a child of the node
	add_child(animation_player)
	
	# Load the new icon texture
	var texture: Texture2D = load("res://new_icon.svg")
	
	# Declare a new animation
	var new_animation = Animation.new()
	
	# Declare the animation track
	var texture_track = new_animation.add_track(Animation.TYPE_VALUE)
	
	# Set the track path to target the Sprite2D's texture property
	new_animation.track_set_path(texture_track, "Sprite2D:texture")
	
	# Insert a key to change the texture to the new icon
	new_animation.track_insert_key(texture_track, 0, texture)
	
	# Add the animation to the library
	animation_library.add_animation("change_texture", new_animation)
	
	# Add the library to the animation player
	animation_player.add_animation_library("", animation_library)
	


# Called every frame. 'delta' is the elapsed time since the previous frame.
func _process(_delta):
	
	# Play the animation
	animation_player.play("change_texture")

Minimal reproduction project (MRP)

GDScriptTextureAnimation.zip

[kleonc]

Happens since v4.2.dev6.official [57a6813].
Probably a regression from #80813? cc @TokageItLab

[TokageItLab]

I guess it could be that for some reason the type determination fails and the value key type is determined to be Nil, causing the interpolation to fail, but I'd have to look into the details.