Reuse cached scene resource if already opened in editor when creating autoloads.

[leandro-benedet-garcia]

What problem(s) does this PR solve?

• Closes [4.8 dev 5] Output window shows errors related to autoloads when opening project settings menu #123524

Additional information

With this PR, the editor checks if a cache already exists and if it does, it instantiates the autoload node from it instead of trying to open the file again.

[KoBeWi]

tbh this code can be replaced simply by Ref<PackedScene> scn = ResourceLoader::load(p_path), which automatically reuses the resource from cache, without all that manual boilerplate. I wonder why it isn't done this way? 🤔

[leandro-benedet-garcia]

tbh this code can be replaced simply by Ref<PackedScene> scn = ResourceLoader::load(p_path), which automatically reuses the resource from cache, without all that manual boilerplate. I wonder why it isn't done this way? 🤔

I was wondering the same, probably legacy code, I will just change to it and then push if I don't see anything wrong with it.

[AThousandShips]

Not sure how it would be legacy code, the loader cache is very old and the UID system is far younger, so I think there might be some potential reason it wasn't used, so good to look into

[KoBeWi]

If you mean the ensure_path(), it was added when autoloads were changed to UID, on top of the original code.

[AThousandShips]

I mean the UID system as such, but that would also be code that's younger than the cache system

[leandro-benedet-garcia]

If you mean the ensure_path(), it was added when autoloads were changed to UID, on top of the original code.

I actually meant the autoload system itself and the people that implemented UID to work around a issue in the autoload system, but I am already investigating and trying just to load stuff.

[leandro-benedet-garcia]

Tested with my own project, tested with the MRP of #69073 and tried to reproduce with the reproduction steps of #123524 All of them are fine with just a load.