Combine bool short names

Adds the ability to allow the combination of bool
short-name options.  For example,

cmd foobar -ov

This is done through a bool "UseShortOptionHandler" set in
the command struct.

Built upon PR #621

Signed-off-by: baude <bbaude@redhat.com>

README.md

@@ -47,6 +47,7 @@ applications in an expressive way.
   * [Version Flag](#version-flag)
     + [Customization](#customization-2)
     + [Full API Example](#full-api-example)
+  * [Combining short Bool options](#combining-short-bool-options)
 - [Contribution Guidelines](#contribution-guidelines)
 
 <!-- tocstop -->
@@ -1410,6 +1411,26 @@ func wopAction(c *cli.Context) error {
 }
 ```
 
+### Combining short Bool options
+
+Traditional use of boolean options using their shortnames look like this:
+```
+# cmd foobar -s -o
+```
+
+Suppose you want users to be able to combine your bool options with their shortname.  This
+can be done using the **UseShortOptionHandling** bool in your commands.  Suppose your program
+has a two bool flags such as *serve* and *option* with the short options of *-o* and
+*-s* respectively. With **UseShortOptionHandling** set to *true*, a user can use a syntax
+like:
+```
+# cmd foobar -so
+```
+
+If you enable the **UseShortOptionHandling*, then you must not use any flags that have a single
+leading *-* or this will result in failures.  For example, **-option** can no longer be used.  Flags
+with two leading dashes (such as **--options**) are still valid.
+
 ## Contribution Guidelines
 
 Feel free to put up a pull request to fix a bug or maybe add a feature. I will

command.go

@@ -55,6 +55,10 @@ type Command struct {
 	HideHelp bool
 	// Boolean to hide this command from help or completion
 	Hidden bool
+	// Boolean to enable short-option handling so user can combine several
+	// single-character bool arguements into one
+	// i.e. foobar -o -v -> foobar -ov
+	UseShortOptionHandling bool
 
 	// Full name of command for help, defaults to full command name, including parent commands.
 	HelpName        string
@@ -141,20 +145,22 @@ func (c Command) Run(ctx *Context) (err error) {
 			} else {
 				flagArgs = args[firstFlagIndex:]
 			}
-
 			// separate combined flags
-			var flagArgsSeparated []string
-			for _, flagArg := range flagArgs {
-				if strings.HasPrefix(flagArg, "-") && strings.HasPrefix(flagArg, "--") == false && len(flagArg) >2 {
-					for _, flagChar := range flagArg[1:] {
-						flagArgsSeparated = append(flagArgsSeparated, "-" + string(flagChar))
+			if c.UseShortOptionHandling {
+				var flagArgsSeparated []string
+				for _, flagArg := range flagArgs {
+					if strings.HasPrefix(flagArg, "-") && strings.HasPrefix(flagArg, "--") == false && len(flagArg) > 2 {
+						for _, flagChar := range flagArg[1:] {
+							flagArgsSeparated = append(flagArgsSeparated, "-"+string(flagChar))
+						}
+					} else {
+						flagArgsSeparated = append(flagArgsSeparated, flagArg)
 					}
-				} else {
-					flagArgsSeparated = append(flagArgsSeparated, flagArg)
 				}
+				err = set.Parse(append(flagArgsSeparated, regularArgs...))
+			} else {
+				err = set.Parse(append(flagArgs, regularArgs...))
 			}
-
-			err = set.Parse(append(flagArgsSeparated, regularArgs...))
 		} else {
 			err = set.Parse(ctx.Args().Tail())
 		}

command_test.go

@@ -11,20 +11,23 @@ import (
 
 func TestCommandFlagParsing(t *testing.T) {
 	cases := []struct {
-		testArgs        []string
-		skipFlagParsing bool
-		skipArgReorder  bool
-		expectedErr     error
+		testArgs               []string
+		skipFlagParsing        bool
+		skipArgReorder         bool
+		expectedErr            error
+		UseShortOptionHandling bool
 	}{
 		// Test normal "not ignoring flags" flow
-		{[]string{"test-cmd", "blah", "blah", "-break"}, false, false, errors.New("flag provided but not defined: -break")},
+		{[]string{"test-cmd", "blah", "blah", "-break"}, false, false, errors.New("flag provided but not defined: -break"), false},
 
 		// Test no arg reorder
-		{[]string{"test-cmd", "blah", "blah", "-break"}, false, true, nil},
+		{[]string{"test-cmd", "blah", "blah", "-break"}, false, true, nil, false},
+
+		{[]string{"test-cmd", "blah", "blah"}, true, false, nil, false},   // Test SkipFlagParsing without any args that look like flags
+		{[]string{"test-cmd", "blah", "-break"}, true, false, nil, false}, // Test SkipFlagParsing with random flag arg
+		{[]string{"test-cmd", "blah", "-help"}, true, false, nil, false},  // Test SkipFlagParsing with "special" help flag arg
+		{[]string{"test-cmd", "blah"}, false, false, nil, true},           // Test UseShortOptionHandling
 
-		{[]string{"test-cmd", "blah", "blah"}, true, false, nil},   // Test SkipFlagParsing without any args that look like flags
-		{[]string{"test-cmd", "blah", "-break"}, true, false, nil}, // Test SkipFlagParsing with random flag arg
-		{[]string{"test-cmd", "blah", "-help"}, true, false, nil},  // Test SkipFlagParsing with "special" help flag arg
 	}
 
 	for _, c := range cases {
@@ -36,13 +39,14 @@ func TestCommandFlagParsing(t *testing.T) {
 		context := NewContext(app, set, nil)
 
 		command := Command{
-			Name:            "test-cmd",
-			Aliases:         []string{"tc"},
-			Usage:           "this is for testing",
-			Description:     "testing",
-			Action:          func(_ *Context) error { return nil },
-			SkipFlagParsing: c.skipFlagParsing,
-			SkipArgReorder:  c.skipArgReorder,
+			Name:                   "test-cmd",
+			Aliases:                []string{"tc"},
+			Usage:                  "this is for testing",
+			Description:            "testing",
+			Action:                 func(_ *Context) error { return nil },
+			SkipFlagParsing:        c.skipFlagParsing,
+			SkipArgReorder:         c.skipArgReorder,
+			UseShortOptionHandling: c.UseShortOptionHandling,
 		}
 
 		err := command.Run(context)

flag_test.go

@@ -1048,6 +1048,31 @@ func TestParseMultiBool(t *testing.T) {
 	a.Run([]string{"run", "--serve"})
 }
 
+func TestParseBoolShortOptionHandle(t *testing.T) {
+	a := App{
+		Commands: []Command{
+			{
+				Name: "foobar",
+				UseShortOptionHandling: true,
+				Action: func(ctx *Context) error {
+					if ctx.Bool("serve") != true {
+						t.Errorf("main name not set")
+					}
+					if ctx.Bool("option") != true {
+						t.Errorf("short name not set")
+					}
+					return nil
+				},
+				Flags: []Flag{
+					BoolFlag{Name: "serve, s"},
+					BoolFlag{Name: "option, o"},
+				},
+			},
+		},
+	}
+	a.Run([]string{"run", "foobar", "-so"})
+}
+
 func TestParseDestinationBool(t *testing.T) {
 	var dest bool
 	a := App{