Merge pull request #10852 from Luap99/cobra

bump cobra to v1.2.1 and update the shell completion scripts

1 files changed, 781 insertions, 0 deletions

diff --git a/vendor/github.com/spf13/cobra/completions.go b/vendor/github.com/spf13/cobra/completions.go
new file mode 100644
index 000000000..b849b9c84
--- /dev/null
+++ b/vendor/github.com/spf13/cobra/completions.go
@@ -0,0 +1,781 @@
+package cobra
+
+import (
+	"fmt"
+	"os"
+	"strings"
+	"sync"
+
+	"github.com/spf13/pflag"
+)
+
+const (
+	// ShellCompRequestCmd is the name of the hidden command that is used to request
+	// completion results from the program.  It is used by the shell completion scripts.
+	ShellCompRequestCmd = "__complete"
+	// ShellCompNoDescRequestCmd is the name of the hidden command that is used to request
+	// completion results without their description.  It is used by the shell completion scripts.
+	ShellCompNoDescRequestCmd = "__completeNoDesc"
+)
+
+// Global map of flag completion functions. Make sure to use flagCompletionMutex before you try to read and write from it.
+var flagCompletionFunctions = map[*pflag.Flag]func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective){}
+
+// lock for reading and writing from flagCompletionFunctions
+var flagCompletionMutex = &sync.RWMutex{}
+
+// ShellCompDirective is a bit map representing the different behaviors the shell
+// can be instructed to have once completions have been provided.
+type ShellCompDirective int
+
+type flagCompError struct {
+	subCommand string
+	flagName   string
+}
+
+func (e *flagCompError) Error() string {
+	return "Subcommand '" + e.subCommand + "' does not support flag '" + e.flagName + "'"
+}
+
+const (
+	// ShellCompDirectiveError indicates an error occurred and completions should be ignored.
+	ShellCompDirectiveError ShellCompDirective = 1 << iota
+
+	// ShellCompDirectiveNoSpace indicates that the shell should not add a space
+	// after the completion even if there is a single completion provided.
+	ShellCompDirectiveNoSpace
+
+	// ShellCompDirectiveNoFileComp indicates that the shell should not provide
+	// file completion even when no completion is provided.
+	ShellCompDirectiveNoFileComp
+
+	// ShellCompDirectiveFilterFileExt indicates that the provided completions
+	// should be used as file extension filters.
+	// For flags, using Command.MarkFlagFilename() and Command.MarkPersistentFlagFilename()
+	// is a shortcut to using this directive explicitly.  The BashCompFilenameExt
+	// annotation can also be used to obtain the same behavior for flags.
+	ShellCompDirectiveFilterFileExt
+
+	// ShellCompDirectiveFilterDirs indicates that only directory names should
+	// be provided in file completion.  To request directory names within another
+	// directory, the returned completions should specify the directory within
+	// which to search.  The BashCompSubdirsInDir annotation can be used to
+	// obtain the same behavior but only for flags.
+	ShellCompDirectiveFilterDirs
+
+	// ===========================================================================
+
+	// All directives using iota should be above this one.
+	// For internal use.
+	shellCompDirectiveMaxValue
+
+	// ShellCompDirectiveDefault indicates to let the shell perform its default
+	// behavior after completions have been provided.
+	// This one must be last to avoid messing up the iota count.
+	ShellCompDirectiveDefault ShellCompDirective = 0
+)
+
+const (
+	// Constants for the completion command
+	compCmdName              = "completion"
+	compCmdNoDescFlagName    = "no-descriptions"
+	compCmdNoDescFlagDesc    = "disable completion descriptions"
+	compCmdNoDescFlagDefault = false
+)
+
+// CompletionOptions are the options to control shell completion
+type CompletionOptions struct {
+	// DisableDefaultCmd prevents Cobra from creating a default 'completion' command
+	DisableDefaultCmd bool
+	// DisableNoDescFlag prevents Cobra from creating the '--no-descriptions' flag
+	// for shells that support completion descriptions
+	DisableNoDescFlag bool
+	// DisableDescriptions turns off all completion descriptions for shells
+	// that support them
+	DisableDescriptions bool
+}
+
+// NoFileCompletions can be used to disable file completion for commands that should
+// not trigger file completions.
+func NoFileCompletions(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective) {
+	return nil, ShellCompDirectiveNoFileComp
+}
+
+// RegisterFlagCompletionFunc should be called to register a function to provide completion for a flag.
+func (c *Command) RegisterFlagCompletionFunc(flagName string, f func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective)) error {
+	flag := c.Flag(flagName)
+	if flag == nil {
+		return fmt.Errorf("RegisterFlagCompletionFunc: flag '%s' does not exist", flagName)
+	}
+	flagCompletionMutex.Lock()
+	defer flagCompletionMutex.Unlock()
+
+	if _, exists := flagCompletionFunctions[flag]; exists {
+		return fmt.Errorf("RegisterFlagCompletionFunc: flag '%s' already registered", flagName)
+	}
+	flagCompletionFunctions[flag] = f
+	return nil
+}
+
+// Returns a string listing the different directive enabled in the specified parameter
+func (d ShellCompDirective) string() string {
+	var directives []string
+	if d&ShellCompDirectiveError != 0 {
+		directives = append(directives, "ShellCompDirectiveError")
+	}
+	if d&ShellCompDirectiveNoSpace != 0 {
+		directives = append(directives, "ShellCompDirectiveNoSpace")
+	}
+	if d&ShellCompDirectiveNoFileComp != 0 {
+		directives = append(directives, "ShellCompDirectiveNoFileComp")
+	}
+	if d&ShellCompDirectiveFilterFileExt != 0 {
+		directives = append(directives, "ShellCompDirectiveFilterFileExt")
+	}
+	if d&ShellCompDirectiveFilterDirs != 0 {
+		directives = append(directives, "ShellCompDirectiveFilterDirs")
+	}
+	if len(directives) == 0 {
+		directives = append(directives, "ShellCompDirectiveDefault")
+	}
+
+	if d >= shellCompDirectiveMaxValue {
+		return fmt.Sprintf("ERROR: unexpected ShellCompDirective value: %d", d)
+	}
+	return strings.Join(directives, ", ")
+}
+
+// Adds a special hidden command that can be used to request custom completions.
+func (c *Command) initCompleteCmd(args []string) {
+	completeCmd := &Command{
+		Use:                   fmt.Sprintf("%s [command-line]", ShellCompRequestCmd),
+		Aliases:               []string{ShellCompNoDescRequestCmd},
+		DisableFlagsInUseLine: true,
+		Hidden:                true,
+		DisableFlagParsing:    true,
+		Args:                  MinimumNArgs(1),
+		Short:                 "Request shell completion choices for the specified command-line",
+		Long: fmt.Sprintf("%[2]s is a special command that is used by the shell completion logic\n%[1]s",
+			"to request completion choices for the specified command-line.", ShellCompRequestCmd),
+		Run: func(cmd *Command, args []string) {
+			finalCmd, completions, directive, err := cmd.getCompletions(args)
+			if err != nil {
+				CompErrorln(err.Error())
+				// Keep going for multiple reasons:
+				// 1- There could be some valid completions even though there was an error
+				// 2- Even without completions, we need to print the directive
+			}
+
+			noDescriptions := (cmd.CalledAs() == ShellCompNoDescRequestCmd)
+			for _, comp := range completions {
+				if noDescriptions {
+					// Remove any description that may be included following a tab character.
+					comp = strings.Split(comp, "\t")[0]
+				}
+
+				// Make sure we only write the first line to the output.
+				// This is needed if a description contains a linebreak.
+				// Otherwise the shell scripts will interpret the other lines as new flags
+				// and could therefore provide a wrong completion.
+				comp = strings.Split(comp, "\n")[0]
+
+				// Finally trim the completion.  This is especially important to get rid
+				// of a trailing tab when there are no description following it.
+				// For example, a sub-command without a description should not be completed
+				// with a tab at the end (or else zsh will show a -- following it
+				// although there is no description).
+				comp = strings.TrimSpace(comp)
+
+				// Print each possible completion to stdout for the completion script to consume.
+				fmt.Fprintln(finalCmd.OutOrStdout(), comp)
+			}
+
+			// As the last printout, print the completion directive for the completion script to parse.
+			// The directive integer must be that last character following a single colon (:).
+			// The completion script expects :<directive>
+			fmt.Fprintf(finalCmd.OutOrStdout(), ":%d\n", directive)
+
+			// Print some helpful info to stderr for the user to understand.
+			// Output from stderr must be ignored by the completion script.
+			fmt.Fprintf(finalCmd.ErrOrStderr(), "Completion ended with directive: %s\n", directive.string())
+		},
+	}
+	c.AddCommand(completeCmd)
+	subCmd, _, err := c.Find(args)
+	if err != nil || subCmd.Name() != ShellCompRequestCmd {
+		// Only create this special command if it is actually being called.
+		// This reduces possible side-effects of creating such a command;
+		// for example, having this command would cause problems to a
+		// cobra program that only consists of the root command, since this
+		// command would cause the root command to suddenly have a subcommand.
+		c.RemoveCommand(completeCmd)
+	}
+}
+
+func (c *Command) getCompletions(args []string) (*Command, []string, ShellCompDirective, error) {
+	// The last argument, which is not completely typed by the user,
+	// should not be part of the list of arguments
+	toComplete := args[len(args)-1]
+	trimmedArgs := args[:len(args)-1]
+
+	var finalCmd *Command
+	var finalArgs []string
+	var err error
+	// Find the real command for which completion must be performed
+	// check if we need to traverse here to parse local flags on parent commands
+	if c.Root().TraverseChildren {
+		finalCmd, finalArgs, err = c.Root().Traverse(trimmedArgs)
+	} else {
+		finalCmd, finalArgs, err = c.Root().Find(trimmedArgs)
+	}
+	if err != nil {
+		// Unable to find the real command. E.g., <program> someInvalidCmd <TAB>
+		return c, []string{}, ShellCompDirectiveDefault, fmt.Errorf("Unable to find a command for arguments: %v", trimmedArgs)
+	}
+	finalCmd.ctx = c.ctx
+
+	// Check if we are doing flag value completion before parsing the flags.
+	// This is important because if we are completing a flag value, we need to also
+	// remove the flag name argument from the list of finalArgs or else the parsing
+	// could fail due to an invalid value (incomplete) for the flag.
+	flag, finalArgs, toComplete, flagErr := checkIfFlagCompletion(finalCmd, finalArgs, toComplete)
+
+	// Check if interspersed is false or -- was set on a previous arg.
+	// This works by counting the arguments. Normally -- is not counted as arg but
+	// if -- was already set or interspersed is false and there is already one arg then
+	// the extra added -- is counted as arg.
+	flagCompletion := true
+	_ = finalCmd.ParseFlags(append(finalArgs, "--"))
+	newArgCount := finalCmd.Flags().NArg()
+
+	// Parse the flags early so we can check if required flags are set
+	if err = finalCmd.ParseFlags(finalArgs); err != nil {
+		return finalCmd, []string{}, ShellCompDirectiveDefault, fmt.Errorf("Error while parsing flags from args %v: %s", finalArgs, err.Error())
+	}
+
+	realArgCount := finalCmd.Flags().NArg()
+	if newArgCount > realArgCount {
+		// don't do flag completion (see above)
+		flagCompletion = false
+	}
+	// Error while attempting to parse flags
+	if flagErr != nil {
+		// If error type is flagCompError and we don't want flagCompletion we should ignore the error
+		if _, ok := flagErr.(*flagCompError); !(ok && !flagCompletion) {
+			return finalCmd, []string{}, ShellCompDirectiveDefault, flagErr
+		}
+	}
+
+	if flag != nil && flagCompletion {
+		// Check if we are completing a flag value subject to annotations
+		if validExts, present := flag.Annotations[BashCompFilenameExt]; present {
+			if len(validExts) != 0 {
+				// File completion filtered by extensions
+				return finalCmd, validExts, ShellCompDirectiveFilterFileExt, nil
+			}
+
+			// The annotation requests simple file completion.  There is no reason to do
+			// that since it is the default behavior anyway.  Let's ignore this annotation
+			// in case the program also registered a completion function for this flag.
+			// Even though it is a mistake on the program's side, let's be nice when we can.
+		}
+
+		if subDir, present := flag.Annotations[BashCompSubdirsInDir]; present {
+			if len(subDir) == 1 {
+				// Directory completion from within a directory
+				return finalCmd, subDir, ShellCompDirectiveFilterDirs, nil
+			}
+			// Directory completion
+			return finalCmd, []string{}, ShellCompDirectiveFilterDirs, nil
+		}
+	}
+
+	// When doing completion of a flag name, as soon as an argument starts with
+	// a '-' we know it is a flag.  We cannot use isFlagArg() here as it requires
+	// the flag name to be complete
+	if flag == nil && len(toComplete) > 0 && toComplete[0] == '-' && !strings.Contains(toComplete, "=") && flagCompletion {
+		var completions []string
+
+		// First check for required flags
+		completions = completeRequireFlags(finalCmd, toComplete)
+
+		// If we have not found any required flags, only then can we show regular flags
+		if len(completions) == 0 {
+			doCompleteFlags := func(flag *pflag.Flag) {
+				if !flag.Changed ||
+					strings.Contains(flag.Value.Type(), "Slice") ||
+					strings.Contains(flag.Value.Type(), "Array") {
+					// If the flag is not already present, or if it can be specified multiple times (Array or Slice)
+					// we suggest it as a completion
+					completions = append(completions, getFlagNameCompletions(flag, toComplete)...)
+				}
+			}
+
+			// We cannot use finalCmd.Flags() because we may not have called ParsedFlags() for commands
+			// that have set DisableFlagParsing; it is ParseFlags() that merges the inherited and
+			// non-inherited flags.
+			finalCmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
+				doCompleteFlags(flag)
+			})
+			finalCmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
+				doCompleteFlags(flag)
+			})
+		}
+
+		directive := ShellCompDirectiveNoFileComp
+		if len(completions) == 1 && strings.HasSuffix(completions[0], "=") {
+			// If there is a single completion, the shell usually adds a space
+			// after the completion.  We don't want that if the flag ends with an =
+			directive = ShellCompDirectiveNoSpace
+		}
+		return finalCmd, completions, directive, nil
+	}
+
+	// We only remove the flags from the arguments if DisableFlagParsing is not set.
+	// This is important for commands which have requested to do their own flag completion.
+	if !finalCmd.DisableFlagParsing {
+		finalArgs = finalCmd.Flags().Args()
+	}
+
+	var completions []string
+	directive := ShellCompDirectiveDefault
+	if flag == nil {
+		foundLocalNonPersistentFlag := false
+		// If TraverseChildren is true on the root command we don't check for
+		// local flags because we can use a local flag on a parent command
+		if !finalCmd.Root().TraverseChildren {
+			// Check if there are any local, non-persistent flags on the command-line
+			localNonPersistentFlags := finalCmd.LocalNonPersistentFlags()
+			finalCmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
+				if localNonPersistentFlags.Lookup(flag.Name) != nil && flag.Changed {
+					foundLocalNonPersistentFlag = true
+				}
+			})
+		}
+
+		// Complete subcommand names, including the help command
+		if len(finalArgs) == 0 && !foundLocalNonPersistentFlag {
+			// We only complete sub-commands if:
+			// - there are no arguments on the command-line and
+			// - there are no local, non-persistent flags on the command-line or TraverseChildren is true
+			for _, subCmd := range finalCmd.Commands() {
+				if subCmd.IsAvailableCommand() || subCmd == finalCmd.helpCommand {
+					if strings.HasPrefix(subCmd.Name(), toComplete) {
+						completions = append(completions, fmt.Sprintf("%s\t%s", subCmd.Name(), subCmd.Short))
+					}
+					directive = ShellCompDirectiveNoFileComp
+				}
+			}
+		}
+
+		// Complete required flags even without the '-' prefix
+		completions = append(completions, completeRequireFlags(finalCmd, toComplete)...)
+
+		// Always complete ValidArgs, even if we are completing a subcommand name.
+		// This is for commands that have both subcommands and ValidArgs.
+		if len(finalCmd.ValidArgs) > 0 {
+			if len(finalArgs) == 0 {
+				// ValidArgs are only for the first argument
+				for _, validArg := range finalCmd.ValidArgs {
+					if strings.HasPrefix(validArg, toComplete) {
+						completions = append(completions, validArg)
+					}
+				}
+				directive = ShellCompDirectiveNoFileComp
+
+				// If no completions were found within commands or ValidArgs,
+				// see if there are any ArgAliases that should be completed.
+				if len(completions) == 0 {
+					for _, argAlias := range finalCmd.ArgAliases {
+						if strings.HasPrefix(argAlias, toComplete) {
+							completions = append(completions, argAlias)
+						}
+					}
+				}
+			}
+
+			// If there are ValidArgs specified (even if they don't match), we stop completion.
+			// Only one of ValidArgs or ValidArgsFunction can be used for a single command.
+			return finalCmd, completions, directive, nil
+		}
+
+		// Let the logic continue so as to add any ValidArgsFunction completions,
+		// even if we already found sub-commands.
+		// This is for commands that have subcommands but also specify a ValidArgsFunction.
+	}
+
+	// Find the completion function for the flag or command
+	var completionFn func(cmd *Command, args []string, toComplete string) ([]string, ShellCompDirective)
+	if flag != nil && flagCompletion {
+		flagCompletionMutex.RLock()
+		completionFn = flagCompletionFunctions[flag]
+		flagCompletionMutex.RUnlock()
+	} else {
+		completionFn = finalCmd.ValidArgsFunction
+	}
+	if completionFn != nil {
+		// Go custom completion defined for this flag or command.
+		// Call the registered completion function to get the completions.
+		var comps []string
+		comps, directive = completionFn(finalCmd, finalArgs, toComplete)
+		completions = append(completions, comps...)
+	}
+
+	return finalCmd, completions, directive, nil
+}
+
+func getFlagNameCompletions(flag *pflag.Flag, toComplete string) []string {
+	if nonCompletableFlag(flag) {
+		return []string{}
+	}
+
+	var completions []string
+	flagName := "--" + flag.Name
+	if strings.HasPrefix(flagName, toComplete) {
+		// Flag without the =
+		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+
+		// Why suggest both long forms: --flag and --flag= ?
+		// This forces the user to *always* have to type either an = or a space after the flag name.
+		// Let's be nice and avoid making users have to do that.
+		// Since boolean flags and shortname flags don't show the = form, let's go that route and never show it.
+		// The = form will still work, we just won't suggest it.
+		// This also makes the list of suggested flags shorter as we avoid all the = forms.
+		//
+		// if len(flag.NoOptDefVal) == 0 {
+		// 	// Flag requires a value, so it can be suffixed with =
+		// 	flagName += "="
+		// 	completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+		// }
+	}
+
+	flagName = "-" + flag.Shorthand
+	if len(flag.Shorthand) > 0 && strings.HasPrefix(flagName, toComplete) {
+		completions = append(completions, fmt.Sprintf("%s\t%s", flagName, flag.Usage))
+	}
+
+	return completions
+}
+
+func completeRequireFlags(finalCmd *Command, toComplete string) []string {
+	var completions []string
+
+	doCompleteRequiredFlags := func(flag *pflag.Flag) {
+		if _, present := flag.Annotations[BashCompOneRequiredFlag]; present {
+			if !flag.Changed {
+				// If the flag is not already present, we suggest it as a completion
+				completions = append(completions, getFlagNameCompletions(flag, toComplete)...)
+			}
+		}
+	}
+
+	// We cannot use finalCmd.Flags() because we may not have called ParsedFlags() for commands
+	// that have set DisableFlagParsing; it is ParseFlags() that merges the inherited and
+	// non-inherited flags.
+	finalCmd.InheritedFlags().VisitAll(func(flag *pflag.Flag) {
+		doCompleteRequiredFlags(flag)
+	})
+	finalCmd.NonInheritedFlags().VisitAll(func(flag *pflag.Flag) {
+		doCompleteRequiredFlags(flag)
+	})
+
+	return completions
+}
+
+func checkIfFlagCompletion(finalCmd *Command, args []string, lastArg string) (*pflag.Flag, []string, string, error) {
+	if finalCmd.DisableFlagParsing {
+		// We only do flag completion if we are allowed to parse flags
+		// This is important for commands which have requested to do their own flag completion.
+		return nil, args, lastArg, nil
+	}
+
+	var flagName string
+	trimmedArgs := args
+	flagWithEqual := false
+	orgLastArg := lastArg
+
+	// When doing completion of a flag name, as soon as an argument starts with
+	// a '-' we know it is a flag.  We cannot use isFlagArg() here as that function
+	// requires the flag name to be complete
+	if len(lastArg) > 0 && lastArg[0] == '-' {
+		if index := strings.Index(lastArg, "="); index >= 0 {
+			// Flag with an =
+			if strings.HasPrefix(lastArg[:index], "--") {
+				// Flag has full name
+				flagName = lastArg[2:index]
+			} else {
+				// Flag is shorthand
+				// We have to get the last shorthand flag name
+				// e.g. `-asd` => d to provide the correct completion
+				// https://github.com/spf13/cobra/issues/1257
+				flagName = lastArg[index-1 : index]
+			}
+			lastArg = lastArg[index+1:]
+			flagWithEqual = true
+		} else {
+			// Normal flag completion
+			return nil, args, lastArg, nil
+		}
+	}
+
+	if len(flagName) == 0 {
+		if len(args) > 0 {
+			prevArg := args[len(args)-1]
+			if isFlagArg(prevArg) {
+				// Only consider the case where the flag does not contain an =.
+				// If the flag contains an = it means it has already been fully processed,
+				// so we don't need to deal with it here.
+				if index := strings.Index(prevArg, "="); index < 0 {
+					if strings.HasPrefix(prevArg, "--") {
+						// Flag has full name
+						flagName = prevArg[2:]
+					} else {
+						// Flag is shorthand
+						// We have to get the last shorthand flag name
+						// e.g. `-asd` => d to provide the correct completion
+						// https://github.com/spf13/cobra/issues/1257
+						flagName = prevArg[len(prevArg)-1:]
+					}
+					// Remove the uncompleted flag or else there could be an error created
+					// for an invalid value for that flag
+					trimmedArgs = args[:len(args)-1]
+				}
+			}
+		}
+	}
+
+	if len(flagName) == 0 {
+		// Not doing flag completion
+		return nil, trimmedArgs, lastArg, nil
+	}
+
+	flag := findFlag(finalCmd, flagName)
+	if flag == nil {
+		// Flag not supported by this command, the interspersed option might be set so return the original args
+		return nil, args, orgLastArg, &flagCompError{subCommand: finalCmd.Name(), flagName: flagName}
+	}
+
+	if !flagWithEqual {
+		if len(flag.NoOptDefVal) != 0 {
+			// We had assumed dealing with a two-word flag but the flag is a boolean flag.
+			// In that case, there is no value following it, so we are not really doing flag completion.
+			// Reset everything to do noun completion.
+			trimmedArgs = args
+			flag = nil
+		}
+	}
+
+	return flag, trimmedArgs, lastArg, nil
+}
+
+// initDefaultCompletionCmd adds a default 'completion' command to c.
+// This function will do nothing if any of the following is true:
+// 1- the feature has been explicitly disabled by the program,
+// 2- c has no subcommands (to avoid creating one),
+// 3- c already has a 'completion' command provided by the program.
+func (c *Command) initDefaultCompletionCmd() {
+	if c.CompletionOptions.DisableDefaultCmd || !c.HasSubCommands() {
+		return
+	}
+
+	for _, cmd := range c.commands {
+		if cmd.Name() == compCmdName || cmd.HasAlias(compCmdName) {
+			// A completion command is already available
+			return
+		}
+	}
+
+	haveNoDescFlag := !c.CompletionOptions.DisableNoDescFlag && !c.CompletionOptions.DisableDescriptions
+
+	completionCmd := &Command{
+		Use:   compCmdName,
+		Short: "generate the autocompletion script for the specified shell",
+		Long: fmt.Sprintf(`
+Generate the autocompletion script for %[1]s for the specified shell.
+See each sub-command's help for details on how to use the generated script.
+`, c.Root().Name()),
+		Args:              NoArgs,
+		ValidArgsFunction: NoFileCompletions,
+	}
+	c.AddCommand(completionCmd)
+
+	out := c.OutOrStdout()
+	noDesc := c.CompletionOptions.DisableDescriptions
+	shortDesc := "generate the autocompletion script for %s"
+	bash := &Command{
+		Use:   "bash",
+		Short: fmt.Sprintf(shortDesc, "bash"),
+		Long: fmt.Sprintf(`
+Generate the autocompletion script for the bash shell.
+
+This script depends on the 'bash-completion' package.
+If it is not installed already, you can install it via your OS's package manager.
+
+To load completions in your current shell session:
+$ source <(%[1]s completion bash)
+
+To load completions for every new session, execute once:
+Linux:
+  $ %[1]s completion bash > /etc/bash_completion.d/%[1]s
+MacOS:
+  $ %[1]s completion bash > /usr/local/etc/bash_completion.d/%[1]s
+
+You will need to start a new shell for this setup to take effect.
+  `, c.Root().Name()),
+		Args:                  NoArgs,
+		DisableFlagsInUseLine: true,
+		ValidArgsFunction:     NoFileCompletions,
+		RunE: func(cmd *Command, args []string) error {
+			return cmd.Root().GenBashCompletionV2(out, !noDesc)
+		},
+	}
+	if haveNoDescFlag {
+		bash.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
+	}
+
+	zsh := &Command{
+		Use:   "zsh",
+		Short: fmt.Sprintf(shortDesc, "zsh"),
+		Long: fmt.Sprintf(`
+Generate the autocompletion script for the zsh shell.
+
+If shell completion is not already enabled in your environment you will need
+to enable it.  You can execute the following once:
+
+$ echo "autoload -U compinit; compinit" >> ~/.zshrc
+
+To load completions for every new session, execute once:
+# Linux:
+$ %[1]s completion zsh > "${fpath[1]}/_%[1]s"
+# macOS:
+$ %[1]s completion zsh > /usr/local/share/zsh/site-functions/_%[1]s
+
+You will need to start a new shell for this setup to take effect.
+`, c.Root().Name()),
+		Args:              NoArgs,
+		ValidArgsFunction: NoFileCompletions,
+		RunE: func(cmd *Command, args []string) error {
+			if noDesc {
+				return cmd.Root().GenZshCompletionNoDesc(out)
+			}
+			return cmd.Root().GenZshCompletion(out)
+		},
+	}
+	if haveNoDescFlag {
+		zsh.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
+	}
+
+	fish := &Command{
+		Use:   "fish",
+		Short: fmt.Sprintf(shortDesc, "fish"),
+		Long: fmt.Sprintf(`
+Generate the autocompletion script for the fish shell.
+
+To load completions in your current shell session:
+$ %[1]s completion fish | source
+
+To load completions for every new session, execute once:
+$ %[1]s completion fish > ~/.config/fish/completions/%[1]s.fish
+
+You will need to start a new shell for this setup to take effect.
+`, c.Root().Name()),
+		Args:              NoArgs,
+		ValidArgsFunction: NoFileCompletions,
+		RunE: func(cmd *Command, args []string) error {
+			return cmd.Root().GenFishCompletion(out, !noDesc)
+		},
+	}
+	if haveNoDescFlag {
+		fish.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
+	}
+
+	powershell := &Command{
+		Use:   "powershell",
+		Short: fmt.Sprintf(shortDesc, "powershell"),
+		Long: fmt.Sprintf(`
+Generate the autocompletion script for powershell.
+
+To load completions in your current shell session:
+PS C:\> %[1]s completion powershell | Out-String | Invoke-Expression
+
+To load completions for every new session, add the output of the above command
+to your powershell profile.
+`, c.Root().Name()),
+		Args:              NoArgs,
+		ValidArgsFunction: NoFileCompletions,
+		RunE: func(cmd *Command, args []string) error {
+			if noDesc {
+				return cmd.Root().GenPowerShellCompletion(out)
+			}
+			return cmd.Root().GenPowerShellCompletionWithDesc(out)
+
+		},
+	}
+	if haveNoDescFlag {
+		powershell.Flags().BoolVar(&noDesc, compCmdNoDescFlagName, compCmdNoDescFlagDefault, compCmdNoDescFlagDesc)
+	}
+
+	completionCmd.AddCommand(bash, zsh, fish, powershell)
+}
+
+func findFlag(cmd *Command, name string) *pflag.Flag {
+	flagSet := cmd.Flags()
+	if len(name) == 1 {
+		// First convert the short flag into a long flag
+		// as the cmd.Flag() search only accepts long flags
+		if short := flagSet.ShorthandLookup(name); short != nil {
+			name = short.Name
+		} else {
+			set := cmd.InheritedFlags()
+			if short = set.ShorthandLookup(name); short != nil {
+				name = short.Name
+			} else {
+				return nil
+			}
+		}
+	}
+	return cmd.Flag(name)
+}
+
+// CompDebug prints the specified string to the same file as where the
+// completion script prints its logs.
+// Note that completion printouts should never be on stdout as they would
+// be wrongly interpreted as actual completion choices by the completion script.
+func CompDebug(msg string, printToStdErr bool) {
+	msg = fmt.Sprintf("[Debug] %s", msg)
+
+	// Such logs are only printed when the user has set the environment
+	// variable BASH_COMP_DEBUG_FILE to the path of some file to be used.
+	if path := os.Getenv("BASH_COMP_DEBUG_FILE"); path != "" {
+		f, err := os.OpenFile(path,
+			os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+		if err == nil {
+			defer f.Close()
+			WriteStringAndCheck(f, msg)
+		}
+	}
+
+	if printToStdErr {
+		// Must print to stderr for this not to be read by the completion script.
+		fmt.Fprint(os.Stderr, msg)
+	}
+}
+
+// CompDebugln prints the specified string with a newline at the end
+// to the same file as where the completion script prints its logs.
+// Such logs are only printed when the user has set the environment
+// variable BASH_COMP_DEBUG_FILE to the path of some file to be used.
+func CompDebugln(msg string, printToStdErr bool) {
+	CompDebug(fmt.Sprintf("%s\n", msg), printToStdErr)
+}
+
+// CompError prints the specified completion message to stderr.
+func CompError(msg string) {
+	msg = fmt.Sprintf("[Error] %s", msg)
+	CompDebug(msg, true)
+}
+
+// CompErrorln prints the specified completion message to stderr with a newline at the end.
+func CompErrorln(msg string) {
+	CompError(fmt.Sprintf("%s\n", msg))
+}