Fixes layer MediaTypes in manifests created from a cross-repository push

Signed-off-by: Brian Bland <brian.bland@docker.com>

distribution/push_v2.go

@@ -311,6 +311,8 @@ func (pd *v2PushDescriptor) Upload(ctx context.Context, progressOutput progress.
 	case distribution.ErrBlobMounted:
 		progress.Updatef(progressOutput, pd.ID(), "Mounted from %s", err.From.Name())
 
+		err.Descriptor.MediaType = schema2.MediaTypeLayer
+
 		pd.pushState.Lock()
 		pd.pushState.confirmedV2 = true
 		pd.pushState.remoteLayers[diffID] = err.Descriptor

integration-cli/docker_cli_push_test.go

@@ -10,6 +10,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/docker/distribution/digest"
 	"github.com/docker/docker/cliconfig"
 	"github.com/docker/docker/pkg/integration/checker"
 	"github.com/go-check/check"
@@ -158,6 +159,9 @@ func (s *DockerRegistrySuite) TestCrossRepositoryLayerPush(c *check.C) {
 	// ensure that none of the layers were mounted from another repository during push
 	c.Assert(strings.Contains(out1, "Mounted from"), check.Equals, false)
 
+	digest1 := digest.DigestRegexp.FindString(out1)
+	c.Assert(len(digest1), checker.GreaterThan, 0, check.Commentf("no digest found for pushed manifest"))
+
 	destRepoName := fmt.Sprintf("%v/dockercli/crossrepopush", privateRegistryURL)
 	// retag the image to upload the same layers to another repo in the same registry
 	dockerCmd(c, "tag", "busybox", destRepoName)
@@ -167,6 +171,10 @@ func (s *DockerRegistrySuite) TestCrossRepositoryLayerPush(c *check.C) {
 	// ensure that layers were mounted from the first repo during push
 	c.Assert(strings.Contains(out2, "Mounted from dockercli/busybox"), check.Equals, true)
 
+	digest2 := digest.DigestRegexp.FindString(out2)
+	c.Assert(len(digest2), checker.GreaterThan, 0, check.Commentf("no digest found for pushed manifest"))
+	c.Assert(digest1, check.Equals, digest2)
+
 	// ensure that we can pull and run the cross-repo-pushed repository
 	dockerCmd(c, "rmi", destRepoName)
 	dockerCmd(c, "pull", destRepoName)
@@ -184,6 +192,9 @@ func (s *DockerSchema1RegistrySuite) TestCrossRepositoryLayerPushNotSupported(c
 	// ensure that none of the layers were mounted from another repository during push
 	c.Assert(strings.Contains(out1, "Mounted from"), check.Equals, false)
 
+	digest1 := digest.DigestRegexp.FindString(out1)
+	c.Assert(len(digest1), checker.GreaterThan, 0, check.Commentf("no digest found for pushed manifest"))
+
 	destRepoName := fmt.Sprintf("%v/dockercli/crossrepopush", privateRegistryURL)
 	// retag the image to upload the same layers to another repo in the same registry
 	dockerCmd(c, "tag", "busybox", destRepoName)
@@ -193,6 +204,10 @@ func (s *DockerSchema1RegistrySuite) TestCrossRepositoryLayerPushNotSupported(c
 	// schema1 registry should not support cross-repo layer mounts, so ensure that this does not happen
 	c.Assert(strings.Contains(out2, "Mounted from dockercli/busybox"), check.Equals, false)
 
+	digest2 := digest.DigestRegexp.FindString(out2)
+	c.Assert(len(digest2), checker.GreaterThan, 0, check.Commentf("no digest found for pushed manifest"))
+	c.Assert(digest1, check.Equals, digest2)
+
 	// ensure that we can pull and run the second pushed repository
 	dockerCmd(c, "rmi", destRepoName)
 	dockerCmd(c, "pull", destRepoName)