Hide the plugin command from help output

main.go

@@ -181,7 +181,7 @@ func wrappedMain() int {
 	cli := &cli.CLI{
 		Args:       args,
 		Commands:   Commands,
-		HelpFunc:   cli.BasicHelpFunc("packer"),
+		HelpFunc:   excludeHelpFunc(Commands, []string{"plugin"}),
 		HelpWriter: os.Stdout,
 		Version:    Version,
 	}
@@ -195,6 +195,27 @@ func wrappedMain() int {
 	return exitCode
 }
 
+// excludeHelpFunc filters commands we don't want to show from the list of
+// commands displayed in packer's help text.
+func excludeHelpFunc(commands map[string]cli.CommandFactory, exclude []string) cli.HelpFunc {
+	// Make search slice into a map so we can use use the `if found` idiom
+	// instead of a nested loop.
+	var excludes = make(map[string]interface{}, len(exclude))
+	for _, item := range exclude {
+		excludes[item] = nil
+	}
+
+	// Create filtered list of commands
+	helpCommands := []string{}
+	for command := range commands {
+		if _, found := excludes[command]; !found {
+			helpCommands = append(helpCommands, command)
+		}
+	}
+
+	return cli.FilteredHelpFunc(helpCommands, cli.BasicHelpFunc("packer"))
+}
+
 // extractMachineReadable checks the args for the machine readable
 // flag and returns whether or not it is on. It modifies the args
 // to remove this flag.

main_test.go

@@ -3,9 +3,36 @@ package main
 import (
 	"math/rand"
 	"reflect"
+	"strings"
 	"testing"
+
+	"github.com/mitchellh/cli"
+	"github.com/mitchellh/packer/command"
 )
 
+func TestExcludeHelpFunc(t *testing.T) {
+	commands := map[string]cli.CommandFactory{
+		"build": func() (cli.Command, error) {
+			return &command.BuildCommand{
+				Meta: command.Meta{},
+			}, nil
+		},
+
+		"fix": func() (cli.Command, error) {
+			return &command.FixCommand{
+				Meta: command.Meta{},
+			}, nil
+		},
+	}
+
+	helpFunc := excludeHelpFunc(commands, []string{"fix"})
+	helpText := helpFunc(commands)
+
+	if strings.Contains(helpText, "fix") {
+		t.Fatal("Found fix in help text even though we excluded it: \n\n%s\n\n", helpText)
+	}
+}
+
 func TestExtractMachineReadable(t *testing.T) {
 	var args, expected, result []string
 	var mr bool