oci transport will remove existing images

[cyphar]

If you try to have a multi-tag image with skopeo (by copying to different tags), then it will delete old tags. I also have a feeling that manifests without tags will be really broken. You can verify this fairly trivially by doing:

% skopeo copy docker://opensuse/amd64:42.2 oci:opensuse:latest
% skopeo copy docker://opensuse/amd64:42.1 oci:opensuse:42.1
% jq . opensuse/index.json
{
  "schemaVersion": 2,
  "manifests": [
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "digest": "sha256:6842a022e2395f4d03350f5917908b4efc1aa80c302990dc74a577ebd7df0bff",
      "size": 349,
      "annotations": {
        "org.opencontainers.image.ref.name": "42.1"
      },
      "platform": {
        "architecture": "amd64",
        "os": "linux"
      }
    }
  ]
}

I'll investigate this later. I found this while trying to increase umoci's testing.

[cyphar]

For reference, IMO this should be handled in a similar way to umoci's oci/casext.UpdateReference implementation.

[cyphar]

I believe this is related to containers/skopeo#369.

[mtrmac]

I don’t think this is containers/skopeo#369 ; it’s just that ociDestination.Commit ignores any pre-existing index and overwrites it with a single-manifest index for the just written manifest. That’s not intentional, contributions to fix this would be welcome.

(Also discussed in #155 .)

[rhatdan]

@mtrmac @cyphar Is this still an issue, Just going through old issues and trying to clean them up.

[mtrmac]

This was fixed in #326 ; when a tag is specified, only that image in the index is added/replaced without affecting other tags. (When no tag is specified, it seems that the first untagged image or image with an empty tag is added/replaced.)

(Note that this does not allow multi-arch images, with the various architectures sharing a tag, yet; see #400 for some work in that direction.)