Merge pull request #184 from github/args-constraint

Consistently institute constraints for position arguments and improve error message

cmd/ghcs/code.go

@@ -19,7 +19,7 @@ func newCodeCmd() *cobra.Command {
 	codeCmd := &cobra.Command{
 		Use:   "code",
 		Short: "Open a codespace in VS Code",
-		Args:  cobra.MaximumNArgs(1),
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return code(codespace, useInsiders)
 		},

cmd/ghcs/common.go

@@ -13,6 +13,7 @@ import (
 	"github.com/AlecAivazis/survey/v2"
 	"github.com/AlecAivazis/survey/v2/terminal"
 	"github.com/github/ghcs/internal/api"
+	"github.com/spf13/cobra"
 	"golang.org/x/term"
 )
 
@@ -144,3 +145,12 @@ func checkAuthorizedKeys(ctx context.Context, client *api.API, user string) erro
 	}
 	return nil // success
 }
+
+var ErrTooManyArgs = errors.New("the command accepts no arguments")
+
+func noArgsConstraint(cmd *cobra.Command, args []string) error {
+	if len(args) > 0 {
+		return ErrTooManyArgs
+	}
+	return nil
+}

cmd/ghcs/create.go

@@ -28,7 +28,7 @@ func newCreateCmd() *cobra.Command {
 	createCmd := &cobra.Command{
 		Use:   "create",
 		Short: "Create a codespace",
-		Args:  cobra.NoArgs,
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return create(opts)
 		},

cmd/ghcs/delete.go

@@ -53,7 +53,7 @@ func newDeleteCmd() *cobra.Command {
 	deleteCmd := &cobra.Command{
 		Use:   "delete",
 		Short: "Delete a codespace",
-		Args:  cobra.NoArgs,
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			if opts.deleteAll && opts.repoFilter != "" {
 				return errors.New("both --all and --repo is not supported")

cmd/ghcs/list.go

@@ -20,7 +20,7 @@ func newListCmd() *cobra.Command {
 	listCmd := &cobra.Command{
 		Use:   "list",
 		Short: "List your codespaces",
-		Args:  cobra.NoArgs,
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return list(opts)
 		},

cmd/ghcs/logs.go

@@ -24,7 +24,7 @@ func newLogsCmd() *cobra.Command {
 	logsCmd := &cobra.Command{
 		Use:   "logs",
 		Short: "Access codespace logs",
-		Args:  cobra.MaximumNArgs(1),
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return logs(context.Background(), log, codespace, follow)
 		},

cmd/ghcs/main/main.go

@@ -7,20 +7,25 @@ import (
 	"os"
 
 	"github.com/github/ghcs/cmd/ghcs"
+	"github.com/spf13/cobra"
 )
 
 func main() {
 	rootCmd := ghcs.NewRootCmd()
-	if err := rootCmd.Execute(); err != nil {
-		explainError(os.Stderr, err)
+	if cmd, err := rootCmd.ExecuteC(); err != nil {
+		explainError(os.Stderr, err, cmd)
 		os.Exit(1)
 	}
 }
 
-func explainError(w io.Writer, err error) {
+func explainError(w io.Writer, err error, cmd *cobra.Command) {
 	if errors.Is(err, ghcs.ErrTokenMissing) {
 		fmt.Fprintln(w, "The GITHUB_TOKEN environment variable is required. Create a Personal Access Token at https://github.com/settings/tokens/new?scopes=repo")
 		fmt.Fprintln(w, "Make sure to enable SSO for your organizations after creating the token.")
 		return
 	}
+	if errors.Is(err, ghcs.ErrTooManyArgs) {
+		_ = cmd.Usage()
+		return
+	}
 }

cmd/ghcs/ports.go

@@ -31,7 +31,7 @@ func newPortsCmd() *cobra.Command {
 	portsCmd := &cobra.Command{
 		Use:   "ports",
 		Short: "List ports in a codespace",
-		Args:  cobra.NoArgs,
+		Args:  noArgsConstraint,
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return ports(codespace, asJSON)
 		},
@@ -158,7 +158,7 @@ func newPortsPublicCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:   "public <port>",
 		Short: "Mark port as public",
-		Args:  cobra.MinimumNArgs(1),
+		Args:  cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			codespace, err := cmd.Flags().GetString("codespace")
 			if err != nil {
@@ -179,7 +179,7 @@ func newPortsPrivateCmd() *cobra.Command {
 	return &cobra.Command{
 		Use:   "private <port>",
 		Short: "Mark port as private",
-		Args:  cobra.MinimumNArgs(1),
+		Args:  cobra.ExactArgs(1),
 		RunE: func(cmd *cobra.Command, args []string) error {
 			codespace, err := cmd.Flags().GetString("codespace")
 			if err != nil {