cobratree · go-clikit

cobra is lenient where a script needs it strict. A command that only holds subcommands succeeds for a word that names none of them. help succeeds for a topic that names no command. And an argument check returns an error that names neither the arguments nor the command. cobratree.Strict fixes the three once the tree is built:

prog gte          unknown command "gte" for "prog" (did you mean "get"?)
prog status       unknown command "status" for "prog" (it is now "get cluster")
prog help crate   unknown help topic "crate": unknown command "crate" for "prog" (did you mean "create"?)
prog power on     requires at least 1 arg(s), only received 0 (usage: prog power on NODES)

root := &cobra.Command{Use: "prog", SilenceErrors: true, SilenceUsage: true}
get := &cobra.Command{Use: "get", Short: "Show things"}
get.AddCommand(&cobra.Command{
	Use:  "cluster [NAME]",
	Args: cobra.MaximumNArgs(1),
	RunE: func(*cobra.Command, []string) error { return nil },
})
root.AddCommand(get)
cobratree.Strict(root, cobratree.Moved(map[string]string{"status": "get cluster"}))

for _, args := range [][]string{
	{"gte"},
	{"status"},
	{"help", "get", "clustr"},
	{"get", "cluster", "a", "b"},
	{"get", "cluster", "--bogus"},
} {
	root.SetArgs(args)
	err := root.Execute()
	code := 1
	if cobratree.IsUsage(err) {
		code = 2
	}
	fmt.Printf("%d %v\n", code, err)
}

2 unknown command "gte" for "prog" (did you mean "get"?)
2 unknown command "status" for "prog" (it is now "get cluster")
2 unknown help topic "get clustr": unknown command "clustr" for "prog get" (did you mean "cluster"?)
2 accepts at most 1 arg(s), received 2 (usage: prog get cluster [NAME])
2 unknown flag: --bogus

ExampleStrict in cobratree/example_test.go. CI runs it and checks its output.

The main names#

Name	What it does
`cobratree.Strict`, `cobratree.Moved`, `cobratree.Topics`	the strict tree; renamed commands; help topics that are no command
`cobratree.Usage`, `cobratree.Usagef`, `cobratree.IsUsage`	mark and tell a usage error, for the exit code
`cobratree.InvalidValue`, `cobratree.FlagError`	one form for a value refused by pflag or by the program
`cobratree.Coded`, `cobratree.Status`	an exit status where the cause is known, read in `main`
`cobratree.ReadBuildInfo`, `cobratree.BuildInfo`	the version, the commit and its time, for a version command

NOTE

The package names no exit code. A program maps a usage error to its own, commonly 2.

Fixed interfaces#

The texts of the errors that the checks of Strict return (decision 24), and those of InvalidValue and FlagError (decision 29). cobra and pflag are imported here and in cobratreetest alone.