Support untagging OCI images (release-engineering#261)

* Support untagging OCI images

* Adjusted checks for manifest media types

pubtools/_quay/tag_docker.py

@@ -42,6 +42,8 @@ class TagDocker:
     ImageDetails = namedtuple("ImageDetails", ["reference", "manifest", "manifest_type", "digest"])
     MANIFEST_LIST_TYPE = "application/vnd.docker.distribution.manifest.list.v2+json"
     MANIFEST_V2S2_TYPE = "application/vnd.docker.distribution.manifest.v2+json"
+    MANIFEST_OCI_LIST_TYPE = "application/vnd.oci.image.index.v1+json"
+    MANIFEST_OCI_V2S2_TYPE = "application/vnd.oci.image.manifest.v1+json"
 
     def __init__(
         self,
@@ -220,13 +222,21 @@ def get_image_details(self, reference: str, executor: Executor) -> Optional[Imag
                 raise
 
         manifest_type = manifest["mediaType"]
-        if manifest_type not in [TagDocker.MANIFEST_V2S2_TYPE, TagDocker.MANIFEST_LIST_TYPE]:
+        if manifest_type not in [
+            TagDocker.MANIFEST_V2S2_TYPE,
+            TagDocker.MANIFEST_LIST_TYPE,
+            TagDocker.MANIFEST_OCI_V2S2_TYPE,
+            TagDocker.MANIFEST_OCI_LIST_TYPE,
+        ]:
             raise BadPushItem(
                 "Image {0} has manifest type different than V2S2 or manifest list".format(reference)
             )
 
         # Check arch if the image is V2S2 manifest
-        if manifest["mediaType"] == TagDocker.MANIFEST_V2S2_TYPE:
+        if manifest["mediaType"] in (
+            TagDocker.MANIFEST_V2S2_TYPE,
+            TagDocker.MANIFEST_OCI_V2S2_TYPE,
+        ):
             arch = executor.skopeo_inspect(reference)["Architecture"]
             # Arch check is not a great way to verify that this is a source image, but there are
             # no better options without having build details
@@ -308,13 +318,19 @@ def tag_remove_calculate_archs(
             )
 
         # Scenario 1: source image
-        if dest_details.manifest_type == TagDocker.MANIFEST_V2S2_TYPE:
+        if dest_details.manifest_type in (
+            TagDocker.MANIFEST_V2S2_TYPE,
+            TagDocker.MANIFEST_OCI_V2S2_TYPE,
+        ):
             return self.tag_remove_calculate_archs_source_image(
                 push_item, source_details, dest_details
             )
 
         # Scenario 2: multiarch image
-        if dest_details.manifest_type == TagDocker.MANIFEST_LIST_TYPE:
+        if dest_details.manifest_type in (
+            TagDocker.MANIFEST_LIST_TYPE,
+            TagDocker.MANIFEST_OCI_LIST_TYPE,
+        ):
             return self.tag_remove_calculate_archs_multiarch_image(
                 push_item, source_details, dest_details
             )