From 3a10545f91107ff5454ddfbc64a9aa655c67962b Mon Sep 17 00:00:00 2001
From: Summer Mousa <smousa@zenoss.com>
Date: Sat, 12 Apr 2014 08:32:53 -0500
Subject: [PATCH] Made bash completion command optional; still need to update
 documentation

---
 app.go     | 23 +++++++++++++++--------
 command.go |  5 ++++-
 flag.go    |  3 +++
 help.go    | 23 ++++++++++++++++-------
 4 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/app.go b/app.go
index 298e7f1..a7c7122 100644
--- a/app.go
+++ b/app.go
@@ -20,6 +20,10 @@ type App struct {
 	Commands []Command
 	// List of flags to parse
 	Flags []Flag
+	// Boolean to enable bash completion commands
+	EnableBashCompletion bool
+	// An action to execute when the bash-completion flag is set
+	BashComplete func(context *Context)
 	// An action to execute before any subcommands are run, but after the context is ready
 	// If a non-nil error is returned, no subcommands are run
 	Before func(context *Context) error
@@ -46,13 +50,14 @@ func compileTime() time.Time {
 // Creates a new cli Application with some reasonable defaults for Name, Usage, Version and Action.
 func NewApp() *App {
 	return &App{
-		Name:     os.Args[0],
-		Usage:    "A new cli application",
-		Version:  "0.0.0",
-		Action:   helpCommand.Action,
-		Compiled: compileTime(),
-		Author:   "Author",
-		Email:    "unknown@email",
+		Name:         os.Args[0],
+		Usage:        "A new cli application",
+		Version:      "0.0.0",
+		BashComplete: DefaultAppComplete,
+		Action:       helpCommand.Action,
+		Compiled:     compileTime(),
+		Author:       "Author",
+		Email:        "unknown@email",
 	}
 }
 
@@ -64,7 +69,9 @@ func (a *App) Run(arguments []string) error {
 	}
 
 	//append version/help flags
-	a.appendFlag(BoolFlag{"generate-bash-completion", ""})
+	if a.EnableBashCompletion {
+		a.appendFlag(BashCompletionFlag)
+	}
 	a.appendFlag(BoolFlag{"version, v", "print the version"})
 	a.appendFlag(BoolFlag{"help, h", "show help"})
 
diff --git a/command.go b/command.go
index 55d5221..60d29aa 100644
--- a/command.go
+++ b/command.go
@@ -29,10 +29,13 @@ func (c Command) Run(ctx *Context) error {
 	// append help to flags
 	c.Flags = append(
 		c.Flags,
-		BoolFlag{"generate-bash-completion", ""},
 		BoolFlag{"help, h", "show help"},
 	)
 
+	if ctx.App.EnableBashCompletion {
+		c.Flags = append(c.Flags, BashCompletionFlag)
+	}
+
 	set := flagSet(c.Name, c.Flags)
 	set.SetOutput(ioutil.Discard)
 
diff --git a/flag.go b/flag.go
index d0af858..d11c80f 100644
--- a/flag.go
+++ b/flag.go
@@ -7,6 +7,9 @@ import (
 	"strings"
 )
 
+// This flag enables bash-completion for all commands and subcommands
+var BashCompletionFlag = BoolFlag{"generate-bash-completion", ""}
+
 // Flag is a common interface related to parsing flags in cli.
 // For more advanced flag parsing techniques, it is recomended that
 // this interface be implemented.
diff --git a/help.go b/help.go
index 6ac03be..64b4bab 100644
--- a/help.go
+++ b/help.go
@@ -60,10 +60,21 @@ var helpCommand = Command{
 
 // Prints help for the App
 var HelpPrinter = printHelp
+
 func ShowAppHelp(c *Context) {
 	HelpPrinter(AppHelpTemplate, c.App)
 }
 
+// Prints the list of subcommands as the default app completion method
+func DefaultAppComplete(c *Context) {
+	for _, command := range c.App.Commands {
+		fmt.Println(command.Name)
+		if command.ShortName != "" {
+			fmt.Println(command.ShortName)
+		}
+	}
+}
+
 // Prints help for the given command
 func ShowCommandHelp(c *Context, command string) {
 	for _, c := range c.App.Commands {
@@ -83,11 +94,9 @@ func ShowVersion(c *Context) {
 
 // Prints the lists of commands within a given context
 func ShowCompletions(c *Context) {
-	for _, command := range c.App.Commands {
-		fmt.Println(command.Name)
-		if command.ShortName != "" {
-			fmt.Println(command.ShortName)
-		}
+	a := c.App
+	if a != nil && a.BashComplete != nil {
+		a.BashComplete(c)
 	}
 }
 
@@ -137,7 +146,7 @@ func checkCommandHelp(c *Context, name string) bool {
 }
 
 func checkCompletions(c *Context) bool {
-	if c.GlobalBool("generate-bash-completion") {
+	if c.GlobalBool(BashCompletionFlag.Name) && c.App.EnableBashCompletion {
 		ShowCompletions(c)
 		return true
 	}
@@ -146,7 +155,7 @@ func checkCompletions(c *Context) bool {
 }
 
 func checkCommandCompletions(c *Context, name string) bool {
-	if c.Bool("generate-bash-completion") {
+	if c.Bool(BashCompletionFlag.Name) && c.App.EnableBashCompletion {
 		ShowCommandCompletions(c, name)
 		return true
 	}