cli/command/manifest: allow unsetting variant and os-version in annotate

cli/command/manifest/annotate.go

@@ -28,6 +28,11 @@ type annotateOptions struct {
 	arch       string
 	osFeatures []string
 	osVersion  string
+
+	// variantChanged and osVersionChanged are set if the flags were passed,
+	// so that an empty value can be used to unset them.
+	variantChanged   bool
+	osVersionChanged bool
 }
 
 // manifestStoreProvider is used in tests to provide a dummy store.
@@ -84,6 +89,8 @@ func newAnnotateCommand(dockerCLI command.Cli) *cobra.Command {
 		RunE: func(cmd *cobra.Command, args []string) error {
 			opts.target = args[0]
 			opts.image = args[1]
+			opts.variantChanged = cmd.Flags().Changed("variant")
+			opts.osVersionChanged = cmd.Flags().Changed("os-version")
 			return runManifestAnnotate(dockerCLI, opts)
 		},
 		DisableFlagsInUseLine: true,
@@ -132,10 +139,10 @@ func runManifestAnnotate(dockerCLI command.Cli, opts annotateOptions) error {
 	for _, osFeature := range opts.osFeatures {
 		imageManifest.Descriptor.Platform.OSFeatures = appendIfUnique(imageManifest.Descriptor.Platform.OSFeatures, osFeature)
 	}
-	if opts.variant != "" {
+	if opts.variantChanged {
 		imageManifest.Descriptor.Platform.Variant = opts.variant
 	}
-	if opts.osVersion != "" {
+	if opts.osVersionChanged {
 		imageManifest.Descriptor.Platform.OSVersion = opts.osVersion
 	}
 

cli/command/manifest/annotate_test.go

@@ -79,3 +79,43 @@ func TestManifestAnnotate(t *testing.T) {
 	expected := golden.Get(t, "inspect-annotate.golden")
 	assert.Check(t, is.Equal(string(expected), actual.String()))
 }
+
+func TestManifestAnnotateUnsetFields(t *testing.T) {
+	manifestStore := store.NewStore(t.TempDir())
+
+	cli := test.NewFakeCli(nil)
+	cli.SetManifestStore(manifestStore)
+	listRef := ref(t, "list:v1")
+	namedRef := ref(t, "alpine:3.0")
+	err := manifestStore.Save(listRef, namedRef, fullImageManifest(t, namedRef))
+	assert.NilError(t, err)
+
+	annotate := func(args ...string) {
+		t.Helper()
+		cmd := newAnnotateCommand(cli)
+		cmd.SetArgs(append([]string{"example.com/list:v1", "example.com/alpine:3.0"}, args...))
+		cmd.SetOut(io.Discard)
+		cmd.SetErr(io.Discard)
+		assert.NilError(t, cmd.Execute())
+	}
+
+	annotate("--os", "linux", "--arch", "arm", "--variant", "v7", "--os-version", "1")
+	imageManifest, err := manifestStore.Get(listRef, namedRef)
+	assert.NilError(t, err)
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.Variant, "v7"))
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.OSVersion, "1"))
+
+	// Not passing the flags should preserve the existing values.
+	annotate()
+	imageManifest, err = manifestStore.Get(listRef, namedRef)
+	assert.NilError(t, err)
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.Variant, "v7"))
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.OSVersion, "1"))
+
+	// Passing an empty value should unset them.
+	annotate("--variant", "", "--os-version", "")
+	imageManifest, err = manifestStore.Get(listRef, namedRef)
+	assert.NilError(t, err)
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.Variant, ""))
+	assert.Check(t, is.Equal(imageManifest.Descriptor.Platform.OSVersion, ""))
+}