[4.0] Materials, duplicated in File Browser, affecting each copy (should get unique IDs instead)

[ArseniyMirniy]

Godot version

[4.0] alpha (any)

System information

Windows 10, but it's irrelevant

Issue description

• If you make a material and save it as a file, you can then make a duplicate in the file browser of Godot editor.
• Unfortunately, if you do so, you will be stuck in the broken scene loop:
• Editing each copy will affect their look in runtime (but not in the editor) – all of them will look the same in runtime
• Deleting any copy will break the game (and the scene), unless you'll re-create the same name copy (or clean the scene file manually)

So, you should not be allowed to copy material files, or they have to receive a unique ID if being copied. Otherwise, it will cause issues at runtime and the deletion of such broken materials.

Steps to reproduce

1. Make a material
2. Save it as a file with .material format
3. Assign to something (like cube mesh)
4. Make another cube mesh
5. Duplicate the material in the file browser (with right click - duplicate)
6. Change new material
7. Assign to the second mesh
8. Run the game (all copies look the same)

Optionally:

1. Delete any copy
2. Run the game
3. It crashed, due to missed material (that isn't even used)

Minimal reproduction project

No response

[ArseniyMirniy]

PS. It is possible, that many other file formats (like scenes) are also affected, I just haven't faced this as my daily use case. This one is just the most obvious one – make a copy of the material and just plug in some other maps.

[Calinou]

Duplicate of #54774.