Update cobra and pflag

Signed-off-by: Lantao Liu <lantaol@google.com>

vendor/github.com/spf13/cobra/args.go

@@ -0,0 +1,98 @@
+package cobra
+
+import (
+	"fmt"
+)
+
+type PositionalArgs func(cmd *Command, args []string) error
+
+// Legacy arg validation has the following behaviour:
+// - root commands with no subcommands can take arbitrary arguments
+// - root commands with subcommands will do subcommand validity checking
+// - subcommands will always accept arbitrary arguments
+func legacyArgs(cmd *Command, args []string) error {
+	// no subcommand, always take args
+	if !cmd.HasSubCommands() {
+		return nil
+	}
+
+	// root command with subcommands, do subcommand checking
+	if !cmd.HasParent() && len(args) > 0 {
+		return fmt.Errorf("unknown command %q for %q%s", args[0], cmd.CommandPath(), cmd.findSuggestions(args[0]))
+	}
+	return nil
+}
+
+// NoArgs returns an error if any args are included
+func NoArgs(cmd *Command, args []string) error {
+	if len(args) > 0 {
+		return fmt.Errorf("unknown command %q for %q", args[0], cmd.CommandPath())
+	}
+	return nil
+}
+
+// OnlyValidArgs returns an error if any args are not in the list of ValidArgs
+func OnlyValidArgs(cmd *Command, args []string) error {
+	if len(cmd.ValidArgs) > 0 {
+		for _, v := range args {
+			if !stringInSlice(v, cmd.ValidArgs) {
+				return fmt.Errorf("invalid argument %q for %q%s", v, cmd.CommandPath(), cmd.findSuggestions(args[0]))
+			}
+		}
+	}
+	return nil
+}
+
+func stringInSlice(a string, list []string) bool {
+	for _, b := range list {
+		if b == a {
+			return true
+		}
+	}
+	return false
+}
+
+// ArbitraryArgs never returns an error
+func ArbitraryArgs(cmd *Command, args []string) error {
+	return nil
+}
+
+// MinimumNArgs returns an error if there is not at least N args
+func MinimumNArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) < n {
+			return fmt.Errorf("requires at least %d arg(s), only received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// MaximumNArgs returns an error if there are more than N args
+func MaximumNArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) > n {
+			return fmt.Errorf("accepts at most %d arg(s), received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// ExactArgs returns an error if there are not exactly n args
+func ExactArgs(n int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) != n {
+			return fmt.Errorf("accepts %d arg(s), received %d", n, len(args))
+		}
+		return nil
+	}
+}
+
+// RangeArgs returns an error if the number of args is not within the expected range
+func RangeArgs(min int, max int) PositionalArgs {
+	return func(cmd *Command, args []string) error {
+		if len(args) < min || len(args) > max {
+			return fmt.Errorf("accepts between %d and %d arg(s), received %d", min, max, len(args))
+		}
+		return nil
+	}
+}

vendor/github.com/spf13/cobra/bash_completions.go

@@ -1,6 +1,7 @@
 package cobra
 
 import (
+	"bytes"
 	"fmt"
 	"io"
 	"os"
@@ -10,19 +11,17 @@ import (
 	"github.com/spf13/pflag"
 )
 
+// Annotations for Bash completion.
 const (
-	BashCompFilenameExt     = "cobra_annotation_bash_completion_filename_extentions"
+	BashCompFilenameExt     = "cobra_annotation_bash_completion_filename_extensions"
 	BashCompCustom          = "cobra_annotation_bash_completion_custom"
 	BashCompOneRequiredFlag = "cobra_annotation_bash_completion_one_required_flag"
 	BashCompSubdirsInDir    = "cobra_annotation_bash_completion_subdirs_in_dir"
 )
 
-func preamble(out io.Writer, name string) error {
-	_, err := fmt.Fprintf(out, "# bash completion for %-36s -*- shell-script -*-\n", name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprint(out, `
+func writePreamble(buf *bytes.Buffer, name string) {
+	buf.WriteString(fmt.Sprintf("# bash completion for %-36s -*- shell-script -*-\n", name))
+	buf.WriteString(`
 __debug()
 {
     if [[ -n ${BASH_COMP_DEBUG_FILE} ]]; then
@@ -87,13 +86,13 @@ __handle_reply()
                 local index flag
                 flag="${cur%%=*}"
                 __index_of_word "${flag}" "${flags_with_completion[@]}"
+                COMPREPLY=()
                 if [[ ${index} -ge 0 ]]; then
-                    COMPREPLY=()
                     PREFIX=""
                     cur="${cur#*=}"
                     ${flags_completion[${index}]}
                     if [ -n "${ZSH_VERSION}" ]; then
-                        # zfs completion needs --flag= prefix
+                        # zsh completion needs --flag= prefix
                         eval "COMPREPLY=( \"\${COMPREPLY[@]/#/${flag}=}\" )"
                     fi
                 fi
@@ -133,7 +132,10 @@ __handle_reply()
         declare -F __custom_func >/dev/null && __custom_func
     fi
 
-    __ltrim_colon_completions "$cur"
+    # available in bash-completion >= 2, not always present on macOS
+    if declare -F __ltrim_colon_completions >/dev/null; then
+        __ltrim_colon_completions "$cur"
+    fi
 }
 
 # The arguments should be in the form "ext1|ext2|extn"
@@ -224,7 +226,7 @@ __handle_command()
     fi
     c=$((c+1))
     __debug "${FUNCNAME[0]}: looking for ${next_command}"
-    declare -F $next_command >/dev/null && $next_command
+    declare -F "$next_command" >/dev/null && $next_command
 }
 
 __handle_word()
@@ -247,16 +249,12 @@ __handle_word()
 }
 
 `)
-	return err
 }
 
-func postscript(w io.Writer, name string) error {
+func writePostscript(buf *bytes.Buffer, name string) {
 	name = strings.Replace(name, ":", "__", -1)
-	_, err := fmt.Fprintf(w, "__start_%s()\n", name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, `{
+	buf.WriteString(fmt.Sprintf("__start_%s()\n", name))
+	buf.WriteString(fmt.Sprintf(`{
     local cur prev words cword
     declare -A flaghash 2>/dev/null || :
     if declare -F _init_completion >/dev/null 2>&1; then
@@ -280,318 +278,227 @@ func postscript(w io.Writer, name string) error {
     __handle_word
 }
 
-`, name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, `if [[ $(type -t compopt) = "builtin" ]]; then
+`, name))
+	buf.WriteString(fmt.Sprintf(`if [[ $(type -t compopt) = "builtin" ]]; then
     complete -o default -F __start_%s %s
 else
     complete -o default -o nospace -F __start_%s %s
 fi
 
-`, name, name, name, name)
-	if err != nil {
-		return err
-	}
-	_, err = fmt.Fprintf(w, "# ex: ts=4 sw=4 et filetype=sh\n")
-	return err
+`, name, name, name, name))
+	buf.WriteString("# ex: ts=4 sw=4 et filetype=sh\n")
 }
 
-func writeCommands(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    commands=()\n"); err != nil {
-		return err
-	}
+func writeCommands(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    commands=()\n")
 	for _, c := range cmd.Commands() {
 		if !c.IsAvailableCommand() || c == cmd.helpCommand {
 			continue
 		}
-		if _, err := fmt.Fprintf(w, "    commands+=(%q)\n", c.Name()); err != nil {
-			return err
-		}
+		buf.WriteString(fmt.Sprintf("    commands+=(%q)\n", c.Name()))
 	}
-	_, err := fmt.Fprintf(w, "\n")
-	return err
+	buf.WriteString("\n")
 }
 
-func writeFlagHandler(name string, annotations map[string][]string, w io.Writer) error {
+func writeFlagHandler(buf *bytes.Buffer, name string, annotations map[string][]string) {
 	for key, value := range annotations {
 		switch key {
 		case BashCompFilenameExt:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
-			if err != nil {
-				return err
-			}
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))
 
+			var ext string
 			if len(value) > 0 {
-				ext := "__handle_filename_extension_flag " + strings.Join(value, "|")
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
+				ext = "__handle_filename_extension_flag " + strings.Join(value, "|")
 			} else {
-				ext := "_filedir"
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
-			}
-			if err != nil {
-				return err
+				ext = "_filedir"
 			}
+			buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", ext))
 		case BashCompCustom:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
-			if err != nil {
-				return err
-			}
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))
 			if len(value) > 0 {
 				handlers := strings.Join(value, "; ")
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", handlers)
+				buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", handlers))
 			} else {
-				_, err = fmt.Fprintf(w, "    flags_completion+=(:)\n")
-			}
-			if err != nil {
-				return err
+				buf.WriteString("    flags_completion+=(:)\n")
 			}
 		case BashCompSubdirsInDir:
-			_, err := fmt.Fprintf(w, "    flags_with_completion+=(%q)\n", name)
+			buf.WriteString(fmt.Sprintf("    flags_with_completion+=(%q)\n", name))
 
+			var ext string
 			if len(value) == 1 {
-				ext := "__handle_subdirs_in_dir_flag " + value[0]
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
+				ext = "__handle_subdirs_in_dir_flag " + value[0]
 			} else {
-				ext := "_filedir -d"
-				_, err = fmt.Fprintf(w, "    flags_completion+=(%q)\n", ext)
-			}
-			if err != nil {
-				return err
+				ext = "_filedir -d"
 			}
+			buf.WriteString(fmt.Sprintf("    flags_completion+=(%q)\n", ext))
 		}
 	}
-	return nil
 }
 
-func writeShortFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeShortFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Shorthand
 	format := "    "
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "two_word_"
 	}
 	format += "flags+=(\"-%s\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return writeFlagHandler("-"+name, flag.Annotations, w)
+	buf.WriteString(fmt.Sprintf(format, name))
+	writeFlagHandler(buf, "-"+name, flag.Annotations)
 }
 
-func writeFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Name
 	format := "    flags+=(\"--%s"
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "="
 	}
 	format += "\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return writeFlagHandler("--"+name, flag.Annotations, w)
+	buf.WriteString(fmt.Sprintf(format, name))
+	writeFlagHandler(buf, "--"+name, flag.Annotations)
 }
 
-func writeLocalNonPersistentFlag(flag *pflag.Flag, w io.Writer) error {
-	b := (len(flag.NoOptDefVal) > 0)
+func writeLocalNonPersistentFlag(buf *bytes.Buffer, flag *pflag.Flag) {
 	name := flag.Name
 	format := "    local_nonpersistent_flags+=(\"--%s"
-	if !b {
+	if len(flag.NoOptDefVal) == 0 {
 		format += "="
 	}
 	format += "\")\n"
-	if _, err := fmt.Fprintf(w, format, name); err != nil {
-		return err
-	}
-	return nil
+	buf.WriteString(fmt.Sprintf(format, name))
 }
 
-func writeFlags(cmd *Command, w io.Writer) error {
-	_, err := fmt.Fprintf(w, `    flags=()
+func writeFlags(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString(`    flags=()
     two_word_flags=()
     local_nonpersistent_flags=()
     flags_with_completion=()
     flags_completion=()
 
 `)
-	if err != nil {
-		return err
-	}
 	localNonPersistentFlags := cmd.LocalNonPersistentFlags()
-	var visitErr error
 	cmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
-		if err := writeFlag(flag, w); err != nil {
-			visitErr = err
+		if nonCompletableFlag(flag) {
 			return
 		}
+		writeFlag(buf, flag)
 		if len(flag.Shorthand) > 0 {
-			if err := writeShortFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeShortFlag(buf, flag)
 		}
 		if localNonPersistentFlags.Lookup(flag.Name) != nil {
-			if err := writeLocalNonPersistentFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeLocalNonPersistentFlag(buf, flag)
 		}
 	})
-	if visitErr != nil {
-		return visitErr
-	}
 	cmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
-		if err := writeFlag(flag, w); err != nil {
-			visitErr = err
+		if nonCompletableFlag(flag) {
 			return
 		}
+		writeFlag(buf, flag)
 		if len(flag.Shorthand) > 0 {
-			if err := writeShortFlag(flag, w); err != nil {
-				visitErr = err
-				return
-			}
+			writeShortFlag(buf, flag)
 		}
 	})
-	if visitErr != nil {
-		return visitErr
-	}
 
-	_, err = fmt.Fprintf(w, "\n")
-	return err
+	buf.WriteString("\n")
 }
 
-func writeRequiredFlag(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    must_have_one_flag=()\n"); err != nil {
-		return err
-	}
+func writeRequiredFlag(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    must_have_one_flag=()\n")
 	flags := cmd.NonInheritedFlags()
-	var visitErr error
 	flags.VisitAll(func(flag *pflag.Flag) {
+		if nonCompletableFlag(flag) {
+			return
+		}
 		for key := range flag.Annotations {
 			switch key {
 			case BashCompOneRequiredFlag:
 				format := "    must_have_one_flag+=(\"--%s"
-				b := (flag.Value.Type() == "bool")
-				if !b {
+				if flag.Value.Type() != "bool" {
 					format += "="
 				}
 				format += "\")\n"
-				if _, err := fmt.Fprintf(w, format, flag.Name); err != nil {
-					visitErr = err
-					return
-				}
+				buf.WriteString(fmt.Sprintf(format, flag.Name))
 
 				if len(flag.Shorthand) > 0 {
-					if _, err := fmt.Fprintf(w, "    must_have_one_flag+=(\"-%s\")\n", flag.Shorthand); err != nil {
-						visitErr = err
-						return
-					}
+					buf.WriteString(fmt.Sprintf("    must_have_one_flag+=(\"-%s\")\n", flag.Shorthand))
 				}
 			}
 		}
 	})
-	return visitErr
 }
 
-func writeRequiredNouns(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    must_have_one_noun=()\n"); err != nil {
-		return err
-	}
+func writeRequiredNouns(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    must_have_one_noun=()\n")
 	sort.Sort(sort.StringSlice(cmd.ValidArgs))
 	for _, value := range cmd.ValidArgs {
-		if _, err := fmt.Fprintf(w, "    must_have_one_noun+=(%q)\n", value); err != nil {
-			return err
-		}
+		buf.WriteString(fmt.Sprintf("    must_have_one_noun+=(%q)\n", value))
 	}
-	return nil
 }
 
-func writeArgAliases(cmd *Command, w io.Writer) error {
-	if _, err := fmt.Fprintf(w, "    noun_aliases=()\n"); err != nil {
-		return err
-	}
+func writeArgAliases(buf *bytes.Buffer, cmd *Command) {
+	buf.WriteString("    noun_aliases=()\n")
 	sort.Sort(sort.StringSlice(cmd.ArgAliases))
 	for _, value := range cmd.ArgAliases {
-		if _, err := fmt.Fprintf(w, "    noun_aliases+=(%q)\n", value); err != nil {
-			return err
-		}
+		buf.WriteString(fmt.Sprintf("    noun_aliases+=(%q)\n", value))
 	}
-	return nil
 }
 
-func gen(cmd *Command, w io.Writer) error {
+func gen(buf *bytes.Buffer, cmd *Command) {
 	for _, c := range cmd.Commands() {
 		if !c.IsAvailableCommand() || c == cmd.helpCommand {
 			continue
 		}
-		if err := gen(c, w); err != nil {
-			return err
-		}
+		gen(buf, c)
 	}
 	commandName := cmd.CommandPath()
 	commandName = strings.Replace(commandName, " ", "_", -1)
 	commandName = strings.Replace(commandName, ":", "__", -1)
-	if _, err := fmt.Fprintf(w, "_%s()\n{\n", commandName); err != nil {
-		return err
-	}
-	if _, err := fmt.Fprintf(w, "    last_command=%q\n", commandName); err != nil {
-		return err
-	}
-	if err := writeCommands(cmd, w); err != nil {
-		return err
-	}
-	if err := writeFlags(cmd, w); err != nil {
-		return err
-	}
-	if err := writeRequiredFlag(cmd, w); err != nil {
-		return err
-	}
-	if err := writeRequiredNouns(cmd, w); err != nil {
-		return err
-	}
-	if err := writeArgAliases(cmd, w); err != nil {
-		return err
-	}
-	if _, err := fmt.Fprintf(w, "}\n\n"); err != nil {
-		return err
-	}
-	return nil
+	buf.WriteString(fmt.Sprintf("_%s()\n{\n", commandName))
+	buf.WriteString(fmt.Sprintf("    last_command=%q\n", commandName))
+	writeCommands(buf, cmd)
+	writeFlags(buf, cmd)
+	writeRequiredFlag(buf, cmd)
+	writeRequiredNouns(buf, cmd)
+	writeArgAliases(buf, cmd)
+	buf.WriteString("}\n\n")
 }
 
-func (cmd *Command) GenBashCompletion(w io.Writer) error {
-	if err := preamble(w, cmd.Name()); err != nil {
-		return err
+// GenBashCompletion generates bash completion file and writes to the passed writer.
+func (c *Command) GenBashCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+	writePreamble(buf, c.Name())
+	if len(c.BashCompletionFunction) > 0 {
+		buf.WriteString(c.BashCompletionFunction + "\n")
 	}
-	if len(cmd.BashCompletionFunction) > 0 {
-		if _, err := fmt.Fprintf(w, "%s\n", cmd.BashCompletionFunction); err != nil {
-			return err
-		}
-	}
-	if err := gen(cmd, w); err != nil {
-		return err
-	}
-	return postscript(w, cmd.Name())
+	gen(buf, c)
+	writePostscript(buf, c.Name())
+
+	_, err := buf.WriteTo(w)
+	return err
 }
 
-func (cmd *Command) GenBashCompletionFile(filename string) error {
+func nonCompletableFlag(flag *pflag.Flag) bool {
+	return flag.Hidden || len(flag.Deprecated) > 0
+}
+
+// GenBashCompletionFile generates bash completion file.
+func (c *Command) GenBashCompletionFile(filename string) error {
 	outFile, err := os.Create(filename)
 	if err != nil {
 		return err
 	}
 	defer outFile.Close()
 
-	return cmd.GenBashCompletion(outFile)
+	return c.GenBashCompletion(outFile)
 }
 
 // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag, if it exists.
-func (cmd *Command) MarkFlagRequired(name string) error {
-	return MarkFlagRequired(cmd.Flags(), name)
+func (c *Command) MarkFlagRequired(name string) error {
+	return MarkFlagRequired(c.Flags(), name)
 }
 
 // MarkPersistentFlagRequired adds the BashCompOneRequiredFlag annotation to the named persistent flag, if it exists.
-func (cmd *Command) MarkPersistentFlagRequired(name string) error {
-	return MarkFlagRequired(cmd.PersistentFlags(), name)
+func (c *Command) MarkPersistentFlagRequired(name string) error {
+	return MarkFlagRequired(c.PersistentFlags(), name)
 }
 
 // MarkFlagRequired adds the BashCompOneRequiredFlag annotation to the named flag in the flag set, if it exists.
@@ -601,20 +508,20 @@ func MarkFlagRequired(flags *pflag.FlagSet, name string) error {
 
 // MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag, if it exists.
 // Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (cmd *Command) MarkFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(cmd.Flags(), name, extensions...)
+func (c *Command) MarkFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.Flags(), name, extensions...)
 }
 
 // MarkFlagCustom adds the BashCompCustom annotation to the named flag, if it exists.
 // Generated bash autocompletion will call the bash function f for the flag.
-func (cmd *Command) MarkFlagCustom(name string, f string) error {
-	return MarkFlagCustom(cmd.Flags(), name, f)
+func (c *Command) MarkFlagCustom(name string, f string) error {
+	return MarkFlagCustom(c.Flags(), name, f)
 }
 
 // MarkPersistentFlagFilename adds the BashCompFilenameExt annotation to the named persistent flag, if it exists.
 // Generated bash autocompletion will select filenames for the flag, limiting to named extensions if provided.
-func (cmd *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
-	return MarkFlagFilename(cmd.PersistentFlags(), name, extensions...)
+func (c *Command) MarkPersistentFlagFilename(name string, extensions ...string) error {
+	return MarkFlagFilename(c.PersistentFlags(), name, extensions...)
 }
 
 // MarkFlagFilename adds the BashCompFilenameExt annotation to the named flag in the flag set, if it exists.

vendor/github.com/spf13/cobra/cobra.go

@@ -27,48 +27,59 @@ import (
 )
 
 var templateFuncs = template.FuncMap{
-	"trim":               strings.TrimSpace,
-	"trimRightSpace":     trimRightSpace,
-	"appendIfNotPresent": appendIfNotPresent,
-	"rpad":               rpad,
-	"gt":                 Gt,
-	"eq":                 Eq,
+	"trim":                    strings.TrimSpace,
+	"trimRightSpace":          trimRightSpace,
+	"trimTrailingWhitespaces": trimRightSpace,
+	"appendIfNotPresent":      appendIfNotPresent,
+	"rpad":                    rpad,
+	"gt":                      Gt,
+	"eq":                      Eq,
 }
 
 var initializers []func()
 
-// automatic prefix matching can be a dangerous thing to automatically enable in CLI tools.
-// Set this to true to enable it
+// EnablePrefixMatching allows to set automatic prefix matching. Automatic prefix matching can be a dangerous thing
+// to automatically enable in CLI tools.
+// Set this to true to enable it.
 var EnablePrefixMatching = false
 
-//EnableCommandSorting controls sorting of the slice of commands, which is turned on by default.
-//To disable sorting, set it to false.
+// EnableCommandSorting controls sorting of the slice of commands, which is turned on by default.
+// To disable sorting, set it to false.
 var EnableCommandSorting = true
 
-//AddTemplateFunc adds a template function that's available to Usage and Help
-//template generation.
+// MousetrapHelpText enables an information splash screen on Windows
+// if the CLI is started from explorer.exe.
+// To disable the mousetrap, just set this variable to blank string ("").
+// Works only on Microsoft Windows.
+var MousetrapHelpText string = `This is a command line tool.
+
+You need to open cmd.exe and run it from there.
+`
+
+// AddTemplateFunc adds a template function that's available to Usage and Help
+// template generation.
 func AddTemplateFunc(name string, tmplFunc interface{}) {
 	templateFuncs[name] = tmplFunc
 }
 
-//AddTemplateFuncs adds multiple template functions availalble to Usage and
-//Help template generation.
+// AddTemplateFuncs adds multiple template functions that are available to Usage and
+// Help template generation.
 func AddTemplateFuncs(tmplFuncs template.FuncMap) {
 	for k, v := range tmplFuncs {
 		templateFuncs[k] = v
 	}
 }
 
-//OnInitialize takes a series of func() arguments and appends them to a slice of func().
+// OnInitialize takes a series of func() arguments and appends them to a slice of func().
 func OnInitialize(y ...func()) {
-	for _, x := range y {
-		initializers = append(initializers, x)
-	}
+	initializers = append(initializers, y...)
 }
 
-//Gt takes two types and checks whether the first type is greater than the second. In case of types Arrays, Chans,
-//Maps and Slices, Gt will compare their lengths. Ints are compared directly while strings are first parsed as
-//ints and then compared.
+// FIXME Gt is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
+// Gt takes two types and checks whether the first type is greater than the second. In case of types Arrays, Chans,
+// Maps and Slices, Gt will compare their lengths. Ints are compared directly while strings are first parsed as
+// ints and then compared.
 func Gt(a interface{}, b interface{}) bool {
 	var left, right int64
 	av := reflect.ValueOf(a)
@@ -96,7 +107,9 @@ func Gt(a interface{}, b interface{}) bool {
 	return left > right
 }
 
-//Eq takes two types and checks whether they are equal. Supported types are int and string. Unsupported types will panic.
+// FIXME Eq is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
+// Eq takes two types and checks whether they are equal. Supported types are int and string. Unsupported types will panic.
 func Eq(a interface{}, b interface{}) bool {
 	av := reflect.ValueOf(a)
 	bv := reflect.ValueOf(b)
@@ -116,7 +129,9 @@ func trimRightSpace(s string) string {
 	return strings.TrimRightFunc(s, unicode.IsSpace)
 }
 
-// appendIfNotPresent will append stringToAppend to the end of s, but only if it's not yet present in s
+// FIXME appendIfNotPresent is unused by cobra and should be removed in a version 2. It exists only for compatibility with users of cobra.
+
+// appendIfNotPresent will append stringToAppend to the end of s, but only if it's not yet present in s.
 func appendIfNotPresent(s, stringToAppend string) string {
 	if strings.Contains(s, stringToAppend) {
 		return s
@@ -124,7 +139,7 @@ func appendIfNotPresent(s, stringToAppend string) string {
 	return s + " " + stringToAppend
 }
 
-//rpad adds padding to the right of a string
+// rpad adds padding to the right of a string.
 func rpad(s string, padding int) string {
 	template := fmt.Sprintf("%%-%ds", padding)
 	return fmt.Sprintf(template, s)
@@ -138,7 +153,7 @@ func tmpl(w io.Writer, text string, data interface{}) error {
 	return t.Execute(w, data)
 }
 
-// ld compares two strings and returns the levenshtein distance between them
+// ld compares two strings and returns the levenshtein distance between them.
 func ld(s, t string, ignoreCase bool) int {
 	if ignoreCase {
 		s = strings.ToLower(s)

vendor/github.com/spf13/cobra/command_win.go

@@ -11,14 +11,8 @@ import (
 
 var preExecHookFn = preExecHook
 
-// enables an information splash screen on Windows if the CLI is started from explorer.exe.
-var MousetrapHelpText string = `This is a command line tool
-
-You need to open cmd.exe and run it from there.
-`
-
 func preExecHook(c *Command) {
-	if mousetrap.StartedByExplorer() {
+	if MousetrapHelpText != "" && mousetrap.StartedByExplorer() {
 		c.Print(MousetrapHelpText)
 		time.Sleep(5 * time.Second)
 		os.Exit(1)

vendor/github.com/spf13/cobra/zsh_completions.go

@@ -0,0 +1,126 @@
+package cobra
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+)
+
+// GenZshCompletionFile generates zsh completion file.
+func (c *Command) GenZshCompletionFile(filename string) error {
+	outFile, err := os.Create(filename)
+	if err != nil {
+		return err
+	}
+	defer outFile.Close()
+
+	return c.GenZshCompletion(outFile)
+}
+
+// GenZshCompletion generates a zsh completion file and writes to the passed writer.
+func (c *Command) GenZshCompletion(w io.Writer) error {
+	buf := new(bytes.Buffer)
+
+	writeHeader(buf, c)
+	maxDepth := maxDepth(c)
+	writeLevelMapping(buf, maxDepth)
+	writeLevelCases(buf, maxDepth, c)
+
+	_, err := buf.WriteTo(w)
+	return err
+}
+
+func writeHeader(w io.Writer, cmd *Command) {
+	fmt.Fprintf(w, "#compdef %s\n\n", cmd.Name())
+}
+
+func maxDepth(c *Command) int {
+	if len(c.Commands()) == 0 {
+		return 0
+	}
+	maxDepthSub := 0
+	for _, s := range c.Commands() {
+		subDepth := maxDepth(s)
+		if subDepth > maxDepthSub {
+			maxDepthSub = subDepth
+		}
+	}
+	return 1 + maxDepthSub
+}
+
+func writeLevelMapping(w io.Writer, numLevels int) {
+	fmt.Fprintln(w, `_arguments \`)
+	for i := 1; i <= numLevels; i++ {
+		fmt.Fprintf(w, `  '%d: :->level%d' \`, i, i)
+		fmt.Fprintln(w)
+	}
+	fmt.Fprintf(w, `  '%d: :%s'`, numLevels+1, "_files")
+	fmt.Fprintln(w)
+}
+
+func writeLevelCases(w io.Writer, maxDepth int, root *Command) {
+	fmt.Fprintln(w, "case $state in")
+	defer fmt.Fprintln(w, "esac")
+
+	for i := 1; i <= maxDepth; i++ {
+		fmt.Fprintf(w, "  level%d)\n", i)
+		writeLevel(w, root, i)
+		fmt.Fprintln(w, "  ;;")
+	}
+	fmt.Fprintln(w, "  *)")
+	fmt.Fprintln(w, "    _arguments '*: :_files'")
+	fmt.Fprintln(w, "  ;;")
+}
+
+func writeLevel(w io.Writer, root *Command, i int) {
+	fmt.Fprintf(w, "    case $words[%d] in\n", i)
+	defer fmt.Fprintln(w, "    esac")
+
+	commands := filterByLevel(root, i)
+	byParent := groupByParent(commands)
+
+	for p, c := range byParent {
+		names := names(c)
+		fmt.Fprintf(w, "      %s)\n", p)
+		fmt.Fprintf(w, "        _arguments '%d: :(%s)'\n", i, strings.Join(names, " "))
+		fmt.Fprintln(w, "      ;;")
+	}
+	fmt.Fprintln(w, "      *)")
+	fmt.Fprintln(w, "        _arguments '*: :_files'")
+	fmt.Fprintln(w, "      ;;")
+
+}
+
+func filterByLevel(c *Command, l int) []*Command {
+	cs := make([]*Command, 0)
+	if l == 0 {
+		cs = append(cs, c)
+		return cs
+	}
+	for _, s := range c.Commands() {
+		cs = append(cs, filterByLevel(s, l-1)...)
+	}
+	return cs
+}
+
+func groupByParent(commands []*Command) map[string][]*Command {
+	m := make(map[string][]*Command)
+	for _, c := range commands {
+		parent := c.Parent()
+		if parent == nil {
+			continue
+		}
+		m[parent.Name()] = append(m[parent.Name()], c)
+	}
+	return m
+}
+
+func names(commands []*Command) []string {
+	ns := make([]string, len(commands))
+	for i, c := range commands {
+		ns[i] = c.Name()
+	}
+	return ns
+}