From e6e641143cf1020d57f73164eed32f38a81a534b Mon Sep 17 00:00:00 2001
From: Jeremy Saenz <jeremy.saenz@gmail.com>
Date: Fri, 1 Nov 2013 06:23:19 -0700
Subject: [PATCH 1/2] JMS #39: App.Run returns an error

---
 app.go      | 7 ++++---
 app_test.go | 6 ++++--
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/app.go b/app.go
index 683f453..14730b3 100644
--- a/app.go
+++ b/app.go
@@ -34,7 +34,7 @@ func NewApp() *App {
 }
 
 // Entry point to the cli app. Parses the arguments slice and routes to the proper flag/args combination
-func (a *App) Run(arguments []string) {
+func (a *App) Run(arguments []string) error {
 	// append help to commands
 	if a.Command(helpCommand.Name) == nil {
 		a.Commands = append(a.Commands, helpCommand)
@@ -54,7 +54,7 @@ func (a *App) Run(arguments []string) {
 		fmt.Println("Incorrect Usage.\n")
 		ShowAppHelp(context)
 		fmt.Println("")
-		os.Exit(1)
+		return err
 	}
 
 	checkHelp(context)
@@ -66,12 +66,13 @@ func (a *App) Run(arguments []string) {
 		c := a.Command(name)
 		if c != nil {
 			c.Run(context)
-			return
+			return nil
 		}
 	}
 
 	// Run default Action
 	a.Action(context)
+	return nil
 }
 
 // Returns the named command on App. Returns nil if the command does not exist
diff --git a/app_test.go b/app_test.go
index 20a568a..6cc488b 100644
--- a/app_test.go
+++ b/app_test.go
@@ -32,8 +32,10 @@ func TestApp_Run(t *testing.T) {
 		s = s + c.Args()[0]
 	}
 
-	app.Run([]string{"command", "foo"})
-	app.Run([]string{"command", "bar"})
+	err := app.Run([]string{"command", "foo"})
+	expect(t, err, nil)
+	err = app.Run([]string{"command", "bar"})
+	expect(t, err, nil)
 	expect(t, s, "foobar")
 }
 

From b25b7a883c89175a9f374409a2b973643b316f22 Mon Sep 17 00:00:00 2001
From: Jeremy Saenz <jeremy.saenz@gmail.com>
Date: Fri, 1 Nov 2013 06:45:19 -0700
Subject: [PATCH 2/2] JMS #39: Removed all calls to os.Exit().

---
 app.go     | 12 ++++++++----
 command.go | 10 ++++++----
 help.go    | 19 ++++++++++++-------
 3 files changed, 26 insertions(+), 15 deletions(-)

diff --git a/app.go b/app.go
index 14730b3..c5ff05a 100644
--- a/app.go
+++ b/app.go
@@ -57,16 +57,20 @@ func (a *App) Run(arguments []string) error {
 		return err
 	}
 
-	checkHelp(context)
-	checkVersion(context)
+	if checkHelp(context) {
+		return nil
+	}
+
+	if checkVersion(context) {
+		return nil
+	}
 
 	args := context.Args()
 	if len(args) > 0 {
 		name := args[0]
 		c := a.Command(name)
 		if c != nil {
-			c.Run(context)
-			return nil
+			return c.Run(context)
 		}
 	}
 
diff --git a/command.go b/command.go
index c26ba2a..03f1c11 100644
--- a/command.go
+++ b/command.go
@@ -3,7 +3,6 @@ package cli
 import (
 	"fmt"
 	"io/ioutil"
-	"os"
 	"strings"
 )
 
@@ -24,7 +23,7 @@ type Command struct {
 }
 
 // Invokes the command given the context, parses ctx.Args() to generate command-specific flags
-func (c Command) Run(ctx *Context) {
+func (c Command) Run(ctx *Context) error {
 	// append help to flags
 	c.Flags = append(
 		c.Flags,
@@ -55,12 +54,15 @@ func (c Command) Run(ctx *Context) {
 		fmt.Println("Incorrect Usage.\n")
 		ShowCommandHelp(ctx, c.Name)
 		fmt.Println("")
-		os.Exit(1)
+		return err
 	}
 
 	context := NewContext(ctx.App, set, ctx.globalSet)
-	checkCommandHelp(context, c.Name)
+	if checkCommandHelp(context, c.Name) {
+		return nil
+	}
 	c.Action(context)
+	return nil
 }
 
 // Returns true if Command.Name or Command.ShortName matches given name
diff --git a/help.go b/help.go
index c34d335..31e0611 100644
--- a/help.go
+++ b/help.go
@@ -73,7 +73,6 @@ func ShowCommandHelp(c *Context, command string) {
 	}
 
 	fmt.Printf("No help topic for '%v'\n", command)
-	os.Exit(1)
 }
 
 // Prints the version number of the App
@@ -88,23 +87,29 @@ func printHelp(templ string, data interface{}) {
 	w.Flush()
 }
 
-func checkVersion(c *Context) {
+func checkVersion(c *Context) bool {
 	if c.GlobalBool("version") {
 		ShowVersion(c)
-		os.Exit(0)
+		return true
 	}
+
+	return false
 }
 
-func checkHelp(c *Context) {
+func checkHelp(c *Context) bool {
 	if c.GlobalBool("h") || c.GlobalBool("help") {
 		ShowAppHelp(c)
-		os.Exit(0)
+		return true
 	}
+
+	return false
 }
 
-func checkCommandHelp(c *Context, name string) {
+func checkCommandHelp(c *Context, name string) bool {
 	if c.Bool("h") || c.Bool("help") {
 		ShowCommandHelp(c, name)
-		os.Exit(0)
+		return true
 	}
+
+	return false
 }