transport: Don't pass default service if unset (#1360)

pkg/v1/remote/transport/bearer.go

@@ -233,7 +233,9 @@ func (bt *bearerTransport) refreshOauth(ctx context.Context) ([]byte, error) {
 
 	v := url.Values{}
 	v.Set("scope", strings.Join(bt.scopes, " "))
-	v.Set("service", bt.service)
+	if bt.service != "" {
+		v.Set("service", bt.service)
+	}
 	v.Set("client_id", defaultUserAgent)
 	if auth.IdentityToken != "" {
 		v.Set("grant_type", "refresh_token")

pkg/v1/remote/transport/transport.go

@@ -76,12 +76,7 @@ func NewWithContext(ctx context.Context, reg name.Registry, auth authn.Authentic
 		if !ok {
 			return nil, fmt.Errorf("malformed www-authenticate, missing realm: %v", pr.parameters)
 		}
-		service, ok := pr.parameters["service"]
-		if !ok {
-			// If the service parameter is not specified, then default it to the registry
-			// with which we are talking.
-			service = reg.String()
-		}
+		service := pr.parameters["service"]
 		bt := &bearerTransport{
 			inner:    t,
 			basic:    auth,

pkg/v1/remote/transport/transport_test.go

@@ -136,9 +136,10 @@ func TestTransportSelectionBearer(t *testing.T) {
 				if got, want := r.FormValue("scope"), testReference.Scope(PullScope); got != want {
 					t.Errorf("FormValue(scope); got %v, want %v", got, want)
 				}
-				// Check that we get the default value (we didn't specify it above)
-				if got, want := r.FormValue("service"), testReference.RegistryStr(); got != want {
-					t.Errorf("FormValue(service); got %v, want %v", got, want)
+				// Check that the service isn't set (we didn't specify it above)
+				// https://github.com/google/go-containerregistry/issues/1359
+				if got, want := r.FormValue("service"), ""; got != want {
+					t.Errorf("FormValue(service); got %q, want %q", got, want)
 				}
 				w.Write([]byte(`{"token": "dfskdjhfkhsjdhfkjhsdf"}`))
 			}