cmd/cue: skip mkRunE in the commandGroup wrapper

mkRunE sets up a CUE *Command with a cue.Context, CUE_STATS_FILE,
and all the other machinery for runnable commands evaluating CUE.
These grouping commands themselves never do anything beyond
giving the user friendlier error messages than Cobra,
so we can skip that machinery entirely.

Signed-off-by: Daniel Martí <[email protected]>
Change-Id: I4e5446ba2b6ce69d56b866a6cd850f350fca95b5
Reviewed-on: https://review.gerrithub.io/c/cue-lang/cue/+/1211268
TryBot-Result: CUEcueckoo <[email protected]>
Reviewed-by: Roger Peppe <[email protected]>

Author: mvdan

cmd/cue/cmd/exp.go

@@ -22,7 +22,7 @@ import (
 )
 
 func newExpCmd(c *Command) *cobra.Command {
-	cmd := commandGroup(c, &cobra.Command{
+	cmd := commandGroup(&cobra.Command{
 		// Experimental commands are hidden by design.
 		Hidden: true,
 

cmd/cue/cmd/get.go

@@ -19,7 +19,7 @@ import (
 )
 
 func newGetCmd(c *Command) *cobra.Command {
-	cmd := commandGroup(c, &cobra.Command{
+	cmd := commandGroup(&cobra.Command{
 		Use:   "get <language> [packages]",
 		Short: "add non-CUE dependencies to the current module",
 		Long: `Get downloads packages or modules for non-CUE languages

cmd/cue/cmd/mod.go

@@ -19,7 +19,7 @@ import (
 )
 
 func newModCmd(c *Command) *cobra.Command {
-	cmd := commandGroup(c, &cobra.Command{
+	cmd := commandGroup(&cobra.Command{
 		Use:   "mod <cmd> [arguments]",
 		Short: "module maintenance",
 		Long: `Mod groups commands which operate on CUE modules.

cmd/cue/cmd/refactor.go

@@ -19,7 +19,7 @@ import (
 )
 
 func newRefactorCmd(c *Command) *cobra.Command {
-	cmd := commandGroup(c, &cobra.Command{
+	cmd := commandGroup(&cobra.Command{
 		// Experimental so far.
 		Hidden: true,
 

cmd/cue/cmd/root.go

@@ -89,7 +89,7 @@ type Stats struct {
 // such as `cue mod` or `cue refactor`. Note that the user can't actually run these commands to
 // do anything useful, but we need RunE for good error messages, as Cobra itself is lacking:
 // https://github.com/spf13/cobra/issues/706
-func commandGroup(c *Command, cmd *cobra.Command) *cobra.Command {
+func commandGroup(cmd *cobra.Command) *cobra.Command {
 	// If the user ran `cue mod nosuchcommand --nosuchflag`, we run the `cue mod` command
 	// because `nosuchcommand` was not a known subcommand.
 	// In such a case, do not fail with "unknown flag"; what matters to the user is that
@@ -98,16 +98,16 @@ func commandGroup(c *Command, cmd *cobra.Command) *cobra.Command {
 	cmd.FParseErrWhitelist.UnknownFlags = true
 
 	name := cmd.Name()
-	cmd.RunE = mkRunE(c, func(cmd *Command, args []string) error {
-		stderr := cmd.Stderr()
+	cmd.RunE = func(cmd *cobra.Command, args []string) error {
+		stderr := cmd.OutOrStderr()
 		if len(args) == 0 {
 			fmt.Fprintf(stderr, "%s must be run as one of its subcommands\n", name)
 		} else {
 			fmt.Fprintf(stderr, "%s must be run as one of its subcommands: unknown subcommand %q\n", name, args[0])
 		}
 		fmt.Fprintf(stderr, "Run 'cue help %s' for known subcommands.\n", name)
 		return ErrPrintedError
-	})
+	}
 	return cmd
 }