Use imageParts.normalizedReference in normalizeTag

This is another step to using reference values instead of strings here.

CHANGES BEHAVIOR: docker.io/busybox is now normalized to docker.io/library/busybox.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

libpod/image/image.go

@@ -459,13 +459,19 @@ func normalizeTag(tag string) (string, error) {
 		return "", err
 	}
 	// If the input doesn't specify a registry, set the registry to localhost
+	var ref reference.Named
 	if !decomposedTag.hasRegistry {
-		ref, err := decomposedTag.referenceWithRegistry(DefaultLocalRegistry)
+		ref, err = decomposedTag.referenceWithRegistry(DefaultLocalRegistry)
+		if err != nil {
+			return "", err
+		}
+	} else {
+		ref, err = decomposedTag.normalizedReference()
 		if err != nil {
 			return "", err
 		}
-		tag = ref.String()
 	}
+	tag = ref.String()
 	// If the input does not have a tag, we need to add one (latest)
 	if !decomposedTag.isTagged {
 		tag = fmt.Sprintf("%s:%s", tag, decomposedTag.tag)

libpod/image/image_test.go

@@ -268,6 +268,7 @@ func TestNormalizeTag(t *testing.T) {
 		{"example.com/busybox:notlatest" + digestSuffix, "example.com/busybox:notlatest" + digestSuffix}, // Qualified name:tag@digest
 		{"busybox:latest", "localhost/busybox:latest"},                                                   // Unqualified name-only
 		{"ns/busybox:latest", "localhost/ns/busybox:latest"},                                             // Unqualified with a dot-less namespace
+		{"docker.io/busybox:latest", "docker.io/library/busybox:latest"},                                 // docker.io without /library/
 	} {
 		res, err := normalizeTag(c.input)
 		if c.expected == "" {