Let custom flags use version aliases

command.go

@@ -161,6 +161,8 @@ type Command struct {
 	globaHelpFlagAdded bool
 	// whether global version flag was added
 	globaVersionFlagAdded bool
+	// generated root version flag
+	versionFlag Flag
 	// whether this is a completion command
 	isCompletionCommand bool
 }

command_setup.go

@@ -104,8 +104,11 @@ func (cmd *Command) setupDefaults(osArgs []string) {
 				localVersionFlag = VersionFlag
 			}
 
-			cmd.appendFlag(localVersionFlag)
-			cmd.globaVersionFlagAdded = true
+			if !flagNamesInUse(cmd.allFlags(), localVersionFlag.Names()) {
+				cmd.appendFlag(localVersionFlag)
+				cmd.versionFlag = localVersionFlag
+				cmd.globaVersionFlagAdded = true
+			}
 		}
 	}
 
@@ -193,6 +196,20 @@ func (cmd *Command) setupSubcommand() {
 	cmd.flagCategories = newFlagCategoriesFromFlags(cmd.allFlags())
 }
 
+func flagNamesInUse(flags []Flag, names []string) bool {
+	for _, name := range names {
+		for _, fl := range flags {
+			for _, flagName := range fl.Names() {
+				if flagName == name {
+					return true
+				}
+			}
+		}
+	}
+
+	return false
+}
+
 func (cmd *Command) hideHelp() bool {
 	tracef("hide help (cmd=%[1]q)", cmd.Name)
 	for c := cmd; c != nil; c = c.parent {

command_test.go

@@ -2392,6 +2392,31 @@ func TestCommand_Run_Version(t *testing.T) {
 	}
 }
 
+func TestCommand_Run_CustomFlagCanUseVersionAlias(t *testing.T) {
+	buf := new(bytes.Buffer)
+	called := false
+
+	cmd := &Command{
+		Name:    "boom",
+		Version: "0.1.0",
+		Writer:  buf,
+		Flags: []Flag{
+			&BoolFlag{Name: "verbose", Aliases: []string{"v"}},
+		},
+		Action: func(_ context.Context, cmd *Command) error {
+			called = true
+			assert.True(t, cmd.Bool("verbose"))
+			return nil
+		},
+	}
+
+	err := cmd.Run(buildTestContext(t), []string{"boom", "-v"})
+
+	assert.NoError(t, err)
+	assert.True(t, called)
+	assert.Empty(t, buf.String())
+}
+
 func TestCommand_Run_Categories(t *testing.T) {
 	buf := new(bytes.Buffer)
 

help.go

@@ -459,13 +459,7 @@ func DefaultPrintHelp(out io.Writer, templ string, data any) {
 }
 
 func checkVersion(cmd *Command) bool {
-	found := false
-	for _, name := range VersionFlag.Names() {
-		if cmd.Bool(name) {
-			found = true
-		}
-	}
-	return found
+	return cmd.versionFlag != nil && cmd.versionFlag.IsSet()
 }
 
 func checkShellCompleteFlag(c *Command, arguments []string) (bool, []string) {