tarsum: version the addition of xattrs

Now that TarSum can be versioned, move the addition of xattr headers in
to the next version of TarSum

Signed-off-by: Vincent Batts <vbatts@redhat.com>

pkg/tarsum/tarsum.go

@@ -81,7 +81,7 @@ func (ts tarSum) selectHeaders(h *tar.Header, v Version) (set [][2]string) {
 		{"devmajor", strconv.Itoa(int(h.Devmajor))},
 		{"devminor", strconv.Itoa(int(h.Devminor))},
 	} {
-		if v == VersionDev && elem[0] == "mtime" {
+		if v >= VersionDev && elem[0] == "mtime" {
 			continue
 		}
 		set = append(set, elem)
@@ -97,14 +97,16 @@ func (ts *tarSum) encodeHeader(h *tar.Header) error {
 	}
 
 	// include the additional pax headers, from an ordered list
-	var keys []string
-	for k := range h.Xattrs {
-		keys = append(keys, k)
-	}
-	sort.Strings(keys)
-	for _, k := range keys {
-		if _, err := ts.h.Write([]byte(k + h.Xattrs[k])); err != nil {
-			return err
+	if ts.Version() >= VersionDev {
+		var keys []string
+		for k := range h.Xattrs {
+			keys = append(keys, k)
+		}
+		sort.Strings(keys)
+		for _, k := range keys {
+			if _, err := ts.h.Write([]byte(k + h.Xattrs[k])); err != nil {
+				return err
+			}
 		}
 	}
 	return nil

pkg/tarsum/tarsum_test.go

@@ -38,10 +38,17 @@ var testLayers = []testLayer{
 		gzip:     true,
 		tarsum:   "tarsum+sha256:e58fcf7418d4390dec8e8fb69d88c06ec07039d651fedd3aa72af9972e7d046b"},
 	{
+		// Tests existing version of TarSum when xattrs are present
 		filename: "testdata/xattr/layer.tar",
 		jsonfile: "testdata/xattr/json",
-		// without xattr support, this layer produces "tarsum+sha256:e86f81a4d552f13039b1396ed03ca968ea9717581f9577ef1876ea6ff9b38c98"
-		tarsum: "tarsum+sha256:eadcd9c55164e2a942ea67f781abbf645ee55d36e173c34de8a36d4d69d3021c"},
+		version:  Version0,
+		tarsum:   "tarsum+sha256:e86f81a4d552f13039b1396ed03ca968ea9717581f9577ef1876ea6ff9b38c98"},
+	{
+		// Tests next version of TarSum when xattrs are present
+		filename: "testdata/xattr/layer.tar",
+		jsonfile: "testdata/xattr/json",
+		version:  VersionDev,
+		tarsum:   "tarsum.dev+sha256:6235cd3a2afb7501bac541772a3d61a3634e95bc90bb39a4676e2cb98d08390d"},
 	{
 		filename: "testdata/511136ea3c5a64f264b78b5433614aec563103b4d4702f3ba7d4d2698e22c158/layer.tar",
 		jsonfile: "testdata/511136ea3c5a64f264b78b5433614aec563103b4d4702f3ba7d4d2698e22c158/json",