All ExtResource ids change after saving (4.1 regression)

[rakkarage]

Godot version

v4.1.dev.custom_build [a8453cb]

System information

Windows 11, Core i5-12400F, RX 6600

Issue description

in recent custom 4.1 builds it is regening every ext id on every save even if just one simple file

[gd_scene load_steps=2 format=3 uid="uid://bj3w1run711x7"]

[ext_resource type="Texture2D" uid="uid://c082xolc76p8n" path="res://icon.svg" id="1_ftki2"]

[node name="Node2D" type="Node2D"]

[node name="Sprite2D" type="Sprite2D" parent="."]
position = Vector2(351, 294)
texture = ExtResource("1_ftki2")

can use a script like this save all files and regen all ext ids in project

@tool
extends EditorScript

func listFiles(path: String, extensions: Array = []) -> Array:
	var list := []
	for dir in DirAccess.get_directories_at(path):
		if not dir.begins_with("."):
			list.append_array(listFiles(path + dir + "/", extensions))
	for file in DirAccess.get_files_at(path):
		var ext := file.split(".")[-1]
		if not file.begins_with(".") and ext != "import":
			if extensions.is_empty() or ext in extensions:
				list.append(path + file)
	return list

func _run() -> void:
	for file in listFiles("res://", ["tscn", "tres"]):
		ResourceSaver.save(load(file))

in 4.0.2 this script does not regen every ext id in the project each time it is run (just when needed) but in latest 4.1 it does
but just ctrl+s works'nt too

thanks

thought it was related to this but maybe not
#76693

Steps to reproduce

• make new scene with ext resource (new control, new sprite, set texture to icon)
  1 - save, stage changes
  2 - goto 1

or can use script on any project to see that it applies to everything, everywhere, all at once

Minimal reproduction project

n/a

[DevanOBoyle]

I'm interested in tackling this issue.

[AThousandShips]

Note that these are ExtResource IDs not SubResource IDs which are non-external, this seems to be handled here:

godot/scene/resources/resource_format_text.cpp

Line 1971 in da21cb7

external_resources[instance] = itos(index) + "_" + Resource::generate_scene_unique_id(); // Keep the order for improved thread loading performance.

And here:

godot/scene/resources/resource_format_text.cpp

Line 1859 in da21cb7

String id = itos(external_resources.size() + 1) + "_" + Resource::generate_scene_unique_id();

[vmedea]

i've noticed this running recent builds of master as well, it makes git history hard to read due to the noise on every save. If it's useful i could bisect it to find what commit introduced this behavior.

[akien-mga]

I've seen this too. Bisecting the regression would be very helpful yes :)

[vmedea]

I narrowed it down to: 8983b20 " Avoid interaction issues between resource loading threads " (#74405)

[KoBeWi]

This issue makes the current version unusable for people using VCS.