Now it should be be possible to:
* upload the same image as a preview or featured image on different extensions;
* upload the same image as an icon on different extensions;
* select the same video/image multiple times while adding previews on Draft or Edit page: first one will be saved, the rest of the duplicates will be ignored.
If all extensions referencing the file in any way are deleted, the file remains in the database: no thumbnail generating or scanning will happen if/when the file gets re-uploaded as a preview or featured image.
In all cases of re-upload `File.user` will not change: this shouldn't be a problem because currently there's no code relying on image ownership.
Version files will remain the only exception from this changed behaviour: it will only be possible to re-upload a version file once the version itself is deleted (which also deletes its file).
As a consequence of this change `File.extension_id` is dropped, because it is no longer possible to choose which extension should be saved there.
Should take care of #157
Reviewed-on: #161
Reviewed-by: Oleg-Komarov <oleg-komarov@noreply.localhost>
Anna Sirota
b0bb4905b2