cli: error out on unknown command

commands/imagetools/root.go

@@ -10,11 +10,12 @@ type RootOptions struct {
 	Builder *string
 }
 
-func RootCmd(dockerCli command.Cli, opts RootOptions) *cobra.Command {
+func RootCmd(rootcmd *cobra.Command, dockerCli command.Cli, opts RootOptions) *cobra.Command {
 	cmd := &cobra.Command{
 		Use:               "imagetools",
 		Short:             "Commands to work on images in registry",
 		ValidArgsFunction: completion.Disable,
+		RunE:              rootcmd.RunE,
 	}
 
 	cmd.AddCommand(

commands/root.go

@@ -1,6 +1,7 @@
 package commands
 
 import (
+	"fmt"
 	"os"
 
 	debugcmd "github.com/docker/buildx/commands/debug"
@@ -36,13 +37,22 @@ func NewRootCmd(name string, isPlugin bool, dockerCli command.Cli) *cobra.Comman
 			if opt.debug {
 				debug.Enable()
 			}
-
 			cmd.SetContext(appcontext.Context())
 			if !isPlugin {
 				return nil
 			}
 			return plugin.PersistentPreRunE(cmd, args)
 		},
+		RunE: func(cmd *cobra.Command, args []string) error {
+			if len(args) == 0 {
+				return cmd.Help()
+			}
+			_ = cmd.Help()
+			return cli.StatusError{
+				StatusCode: 1,
+				Status:     fmt.Sprintf("ERROR: unknown command: %q", args[0]),
+			}
+		},
 	}
 	if !isPlugin {
 		// match plugin behavior for standalone mode
@@ -95,7 +105,7 @@ func addCommands(cmd *cobra.Command, opts *rootOptions, dockerCli command.Cli) {
 		versionCmd(dockerCli),
 		pruneCmd(dockerCli, opts),
 		duCmd(dockerCli, opts),
-		imagetoolscmd.RootCmd(dockerCli, imagetoolscmd.RootOptions{Builder: &opts.builder}),
+		imagetoolscmd.RootCmd(cmd, dockerCli, imagetoolscmd.RootOptions{Builder: &opts.builder}),
 	)
 	if confutil.IsExperimental() {
 		cmd.AddCommand(debugcmd.RootCmd(dockerCli,

tests/common.go

@@ -0,0 +1,29 @@
+package tests
+
+import (
+	"testing"
+
+	"github.com/moby/buildkit/util/testutil/integration"
+	"github.com/stretchr/testify/require"
+)
+
+var commonTests = []func(t *testing.T, sb integration.Sandbox){
+	testUnknownCommand,
+	testUnknownFlag,
+}
+
+func testUnknownCommand(t *testing.T, sb integration.Sandbox) {
+	cmd := buildxCmd(sb, withArgs("foo"))
+	out, err := cmd.CombinedOutput()
+	require.Error(t, err, string(out))
+
+	cmd = buildxCmd(sb, withArgs("imagetools", "foo"))
+	out, err = cmd.CombinedOutput()
+	require.Error(t, err, string(out))
+}
+
+func testUnknownFlag(t *testing.T, sb integration.Sandbox) {
+	cmd := buildxCmd(sb, withArgs("build", "--foo=bar"))
+	out, err := cmd.CombinedOutput()
+	require.Error(t, err, string(out))
+}

tests/integration_test.go

@@ -21,6 +21,7 @@ func init() {
 
 func TestIntegration(t *testing.T) {
 	var tests []func(t *testing.T, sb integration.Sandbox)
+	tests = append(tests, commonTests...)
 	tests = append(tests, buildTests...)
 	tests = append(tests, bakeTests...)
 	tests = append(tests, inspectTests...)