It is desirable to remove Platform from distribution.Descriptor because it doesn't really belong there. However this would be a further breaking change because the References() call would no longer be returning plaform information when it reurns descriptors of manifests, which is started to for OCI Indices after c94f288 and this feature was added to Docker Manifest Lists in 1a059fe. I don't want to take away something people clearly want.
Signed-off-by: Bracken Dawson <abdawson@gmail.com>
Empty platform structs were already supported after splitting OCI Image
Index out from Docker Manifest List.
Signed-off-by: Bracken Dawson <abdawson@gmail.com>
Move implementation of the index from the manifestlist package to the ocischema package so that other modules making empty imports support the manifest types their authors would expect. This is a breaking change to distribution as a library but not the registry.
As OCI 1.0 released the manifest and index together, that is a good package from which to initialise both manifests. The docker manifest and manifest list remain in separate packages because one was released later.
The image index and manifest list still share common code in many functions not intended for import by other modules.
Signed-off-by: Bracken Dawson <abdawson@gmail.com>
