Fix image replication for images with remote layers

data/registry_model/registry_pre_oci_model.py

@@ -584,5 +584,15 @@ class PreOCIModel(SharedModel, RegistryDataInterface):
     """
     return self._list_manifest_layers(repository_ref._db_id, parsed_manifest, include_placements)
 
+  def get_manifest_local_blobs(self, manifest, include_placements=False):
+    """ Returns the set of local blobs for the given manifest or None if none. """
+    try:
+      tag_manifest = database.TagManifest.get(id=manifest._db_id)
+    except database.TagManifest.DoesNotExist:
+      return None
+
+    return self._get_manifest_local_blobs(manifest, tag_manifest.tag.repository_id,
+                                          include_placements)
+
 
 pre_oci_model = PreOCIModel()