remove use of os.Exit (#851)

cmd/kn/main.go

@@ -33,8 +33,13 @@ var err error
 func main() {
 	defer cleanup()
 	rand.Seed(time.Now().UnixNano())
-	err = core.NewDefaultKnCommand().Execute()
+	kn, err := core.NewDefaultKnCommand()
 	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	if err := kn.Execute(); err != nil {
 		if err.Error() != "subcommand is required" {
 			fmt.Fprintln(os.Stderr, err)
 		}

pkg/kn/commands/plugin/handler.go

@@ -113,10 +113,10 @@ func (h *DefaultPluginHandler) Execute(executablePath string, cmdArgs, environme
 		cmd.Stdin = os.Stdin
 		cmd.Env = environment
 		err := cmd.Run()
-		if err == nil {
-			os.Exit(0)
+		if err != nil {
+			return err
 		}
-		return err
+		return nil
 	}
 	return syscall.Exec(executablePath, cmdArgs, environment)
 }

pkg/kn/core/root.go

@@ -44,7 +44,7 @@ import (
 )
 
 // NewDefaultKnCommand creates the default `kn` command with a default plugin handler
-func NewDefaultKnCommand() *cobra.Command {
+func NewDefaultKnCommand() (*cobra.Command, error) {
 	rootCmd := NewKnCommand()
 
 	// Needed since otherwise --plugins-dir and --lookup-plugins
@@ -53,7 +53,7 @@ func NewDefaultKnCommand() *cobra.Command {
 	pluginsDir, lookupPluginsInPath, err := extractKnPluginFlags(os.Args)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "%v\n", err)
-		os.Exit(1)
+		return &cobra.Command{}, fmt.Errorf("%v", err)
 	}
 
 	pluginHandler := plugin.NewDefaultPluginHandler(plugin.ValidPluginFilenamePrefixes,
@@ -70,9 +70,9 @@ func NewDefaultKnCommandWithArgs(rootCmd *cobra.Command,
 	args []string,
 	in io.Reader,
 	out,
-	errOut io.Writer) *cobra.Command {
+	errOut io.Writer) (*cobra.Command, error) {
 	if pluginHandler == nil {
-		return rootCmd
+		return rootCmd, nil
 	}
 	if len(args) > 1 {
 		cmdPathPieces := args[1:]
@@ -84,18 +84,16 @@ func NewDefaultKnCommandWithArgs(rootCmd *cobra.Command,
 		if err != nil || plugin.InAllowedExtensibleCommandGroups(foundCmd.Name()) {
 			err := plugin.HandlePluginCommand(pluginHandler, cmdPathPieces)
 			if err != nil {
-				fmt.Fprintf(rootCmd.OutOrStderr(), "Error: unknown command '%s' \nRun 'kn --help' for usage.\n", args[1])
-				os.Exit(1)
+				return &cobra.Command{}, fmt.Errorf("unknown command '%s' \nRun 'kn --help' for usage", args[1])
 			}
 		} else if foundCmd.HasSubCommands() {
 			if _, _, err := rootCmd.Find(innerArgs); err != nil {
-				fmt.Fprintf(rootCmd.OutOrStderr(), showSubcommands(foundCmd, cmdPathPieces, innerArgs[0]))
-				os.Exit(1)
+				return &cobra.Command{}, fmt.Errorf(showSubcommands(foundCmd, cmdPathPieces, innerArgs[0]))
 			}
 		}
 	}
 
-	return rootCmd
+	return rootCmd, nil
 }
 
 // NewKnCommand creates the rootCmd which is the base command when called without any subcommands
@@ -232,8 +230,7 @@ func initConfig() {
 func defaultConfigDir() (string, error) {
 	home, err := homedir.Dir()
 	if err != nil {
-		fmt.Fprintf(os.Stderr, "%v\n", err)
-		os.Exit(1)
+		return "", fmt.Errorf("%v", err)
 	}
 	// Check the deprecated path first and fallback to it, add warning to error message
 	if configHome := filepath.Join(home, ".kn"); dirExists(configHome) {

pkg/kn/core/root_test.go

@@ -30,7 +30,7 @@ func TestNewDefaultKnCommand(t *testing.T) {
 	var rootCmd *cobra.Command
 
 	setup := func(t *testing.T) {
-		rootCmd = NewDefaultKnCommand()
+		rootCmd, _ = NewDefaultKnCommand()
 	}
 
 	t.Run("returns a valid root command", func(t *testing.T) {
@@ -48,7 +48,7 @@ func TestNewDefaultKnCommandWithArgs(t *testing.T) {
 	)
 
 	setup := func(t *testing.T) {
-		rootCmd = NewDefaultKnCommandWithArgs(NewKnCommand(), pluginHandler, args, os.Stdin, os.Stdout, os.Stderr)
+		rootCmd, _ = NewDefaultKnCommandWithArgs(NewKnCommand(), pluginHandler, args, os.Stdin, os.Stdout, os.Stderr)
 	}
 
 	t.Run("when pluginHandler is nil", func(t *testing.T) {

test/e2e/basic_workflow_test.go

@@ -82,7 +82,7 @@ func TestWrongCommand(t *testing.T) {
 	r.AssertError(out)
 
 	out = test.Kn{}.Run("rev")
-	assert.Check(t, util.ContainsAll(out.Stderr, "Error", "unknown command", "rev"))
+	assert.Check(t, util.ContainsAll(out.Stderr, "unknown command", "rev"))
 	r.AssertError(out)
 
 }