Need an error when the command is not found in the subcommand

[timidsmile]

hi

Description

When I execute a job on our task center, I need to get the final result of the execution, for example:

myapp job1 args1

When job1 doesn't exist, I can get the error:

Error: unknown command "job1" for ""
Run ' --help' for usage.

Then the task center can be accessed by echo $? to get the final execution result.
However, when I use a subcommand, I can't get the error.

How to reproduce

For example :

package main

import (
	"github.com/spf13/cobra"
)

func main() {
	var rootCmd = &cobra.Command{}

	configCmd := cobra.Command{
		Use: "config",
	}

	getCmd := cobra.Command{
		Use: "set",
		Run: func(cmd *cobra.Command, args []string) {
			println("this is the config set")
		},
	}
	setCmd := cobra.Command{
		Use: "get",
		Run: func(cmd *cobra.Command, args []string) {
			println("this is the config get")
		},
	}
	configCmd.AddCommand(&getCmd)
	configCmd.AddCommand(&setCmd)
	rootCmd.AddCommand(&configCmd)

	if err := rootCmd.Execute(); err != nil {
		panic(err.Error())
	}
}

When I execute:

myapp config xxx

I can get the following prompt without an error.

Usage:
   config [command]

Available Commands:
  get         
  set         

Flags:
  -h, --help   help for config

Use " config [command] --help" for more information about a command.

Expectations

Need to return error

---

Is there some special consideration here?
https://github.com/spf13/cobra/blob/main/command.go#L1123

[marckhouzam]

You can play around with adding the Args field.

If you search issues you’ll find there have been multiple discussions about this.

[andremueller]

I think the main problem is here:

cobra/command.go

Lines 925 to 927 in e94f6d0

	if !c.Runnable() {
	return flag.ErrHelp
	}

If we could just return another error code instead of flag.ErrHelp lets say ErrUnknownSubcommand then the outer error would be forwarded in the lines @timidsmile mentioned, and the user at the outside call of e.g. rootCmd.Execute() could handle that error and print e.g. help or call os.exit(1) - that would solve many problems here. When automating things with scripts we have otherwise no idea when a sub-command is not even implemented! Would this really break the API for the others? Should I pose a merge request with that patch?

In my opinion it must be possible to differentiate between calling help and an unknown subcommand! So a few lines above the help command uses the same error code!

cobra/command.go

Lines 905 to 907 in e94f6d0

	if helpVal {
	return flag.ErrHelp
	}

[marckhouzam]

and the user at the outside call of e.g. rootCmd.Execute() could handle that error and print e.g. help or call os.exit(1)

This requires the caller to change their code to keep the current behavior, which breaks backwards compatibility. If this is important enough, then we could add this as an optional opt-in behavior.

[andremueller]

Ok. What about a further flag in the Command struct such like

type Command struct {
   // everything else ...
   ErrorOnUnknownSubcommand bool
}

Default is false - and we would then change the lines in Execute like this

	if !c.Runnable() {
               if c.ErrorOnUnknownSubcommand {
                  return ErrUnknownSubcommand
               } else {
		   return flag.ErrHelp
              }
	}

would that be fine? All users who really want this feature can just activate it - and all others will not care.

[marckhouzam]

That seems reasonable