Allow projects to reference classes from other projects, even if not present on the filesystem

[antonWetzel]

Describe the project you are working on

Rougelike with planned mod support by loading resource packs

• language: CSharp
• base game not open source
• rooms as packed scenes
• enemies as inherited packed scenes from core class
• items as scripts placed on child nodes
• mods/content packs as complementary projects

At boot time the game loads all resource packs in a folder and has a collection of enemies, rooms, ... to create the game content

Describe the problem or limitation you are having in your project

I can't reference Scripts and Scenes from the core game in the editor in the complementary project.

• can't reuse enemies in a new room
• can't reuse items for a new enemy

Describe the feature / enhancement and how it helps to overcome the problem or limitation

A godot Project can be marked as complementary

• Scripts and PackedScenes can be 'unknown'
  • manual path selection
  • exported Variables can be edited like Metadata without validation
• run is replaced with export and run
  • export pck to export path (games extra content folder)
  • run game (no clue how much debugging is possible with exported game)
• optional / future
  • base game can be exported as placeholder
  • placeholder contains all selected scripts and scenes with only exported variables
  • placeholder can't be edited in the editor
  • placeholder is excluded from the exported pck

Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

The Resource file format can mark a external resource as 'unknown' and the editor allows to edit properties without validation

[ext_resource type="Script" path="res://Core/Script.cs" id="1_h1no0" unknown]
[ext_resource type="PackedScene" path="res://Core/Scene.tscn" id="7_qa0ue" unknown]

The 'unknown' tag is removed at export

If this enhancement will not be used often, can it be worked around with a few lines of script?

not possible

Is there a reason why this should be core and not an add-on in the asset library?

not possible

[Calinou]

Related to #1205.

[antonWetzel]

I think is it possible to replace this with an addon, which contains

• script_placeholder.gd with @export var path: String and @export var data: Dictionary
• scene_placeholder.tscn with a single Node and script_placeholder.gd attached
• An EditorExportPlugin to replace the placeholders on export

My problem is, that I would like to use SceneState but the build API is not public to GDScript.