ahmetb/kubectx · error

write error: %w

Error message

write error: %w

What it means

Wraps the error from writing the kubens usage/help text to the output writer inside printUsage. It fires when the io.Writer provided by Run fails while emitting the help template (broken pipe, closed/unwritable stdout), and is unrelated to the content or validity of the usage text.

Source

Thrown at cmd/kubens/help.go:50

func printUsage(out io.Writer) error {
	help := `Switch between Kubernetes namespaces.

USAGE:
  %PROG%                    : list the namespaces in the current context
  %PROG% <NAME>             : change the active namespace of current context
  %PROG% <NAME> --force/-f  : force change the active namespace of current context (even if it doesn't exist)
  %PROG% -                  : switch to the previous namespace in this context
  %PROG% -c, --current      : show the current namespace
  %PROG% -h,--help          : show this message
  %PROG% -u,--unset         : unset the namespace choice (set to 'default')
  %PROG% -V,--version       : show version`

	// TODO this replace logic is duplicated between this and kubectx
	help = strings.ReplaceAll(help, "%PROG%", selfName())

	_, err := fmt.Fprintf(out, "%s\n", help)
	if err != nil {
		return fmt.Errorf("write error: %w", err)
	}
	return nil
}

// selfName guesses how the user invoked the program.
func selfName() string {
	// TODO this method is duplicated between this and kubectx
	me := filepath.Base(os.Args[0])
	pluginPrefix := "kubectl-"
	if strings.HasPrefix(me, pluginPrefix) {
		return "kubectl " + strings.TrimPrefix(me, pluginPrefix)
	}
	return "kubens"
}

View on GitHub (pinned to 12ad6fb22e)

Solutions

1. Ensure stdout/stderr is not closed when invoking kubens --help
2. If piping help output (e.g. kubens -h | head), the pipe may close early; this is usually harmless

When it happens

Trigger: Thrown at cmd/kubens/help.go:50 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of ahmetb/kubectx@12ad6fb22e (2026-09-02). Data as JSON: /api/errors/ebf63514ddf3d2a1. Report an issue: GitHub.