feat(changelog): add version flag -v to show version information

cmd/main.go

@@ -6,8 +6,21 @@ import (
 	"github.com/zbindenren/cc/internal/cmd"
 )
 
+// nolint: gochecknoglobals
+// following variables are set during build by goreleaser
+var (
+	version = "dev"
+	commit  = "12345678"
+	date    = ""
+)
+
 func main() {
-	command := cmd.New()
+	b, err := cmd.NewBuildInfo(version, date, commit)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	command := cmd.New(*b)
 	if err := command.Run(); err != nil {
 		log.Fatal(err)
 	}

internal/cmd/cmd.go

@@ -28,6 +28,7 @@ const (
 	sinceTagOptName       = "since"
 	initDfltConfigOptName = "init-config"
 	noPromptOptName       = "n"
+	versionOptName        = "v"
 
 	dfltChangelogFile = "CHANGELOG.md"
 	dateFormat        = "2006-01-02"
@@ -37,6 +38,7 @@ const (
 type Command struct {
 	noop bool // for tests
 	fs   *flag.FlagSet
+	b    BuildInfo
 	// flags
 	file       *string
 	debug      *bool
@@ -46,14 +48,16 @@ type Command struct {
 	sinceTag   *string
 	initConfig *bool
 	noPrompt   *bool
+	version    *bool
 }
 
 // New creates a new Command.
-func New() *Command {
+func New(b BuildInfo) *Command {
 	fs := flag.NewFlagSet("changelog", flag.ExitOnError)
 
 	return &Command{
 		fs:         fs,
+		b:          b,
 		file:       fs.String(fileOptName, dfltChangelogFile, "changelog file name"),
 		debug:      fs.Bool(debugOptName, false, "log debug information"),
 		toStdOut:   fs.Bool(stdOutOptName, false, "output changelog to stdout instead to file"),
@@ -62,6 +66,7 @@ func New() *Command {
 		sinceTag:   fs.String(sinceTagOptName, "", fmt.Sprintf("in combination with -%s: if a tag is specified, the changelog will be created from that tag on", historyOptName)),
 		initConfig: fs.Bool(initDfltConfigOptName, false, fmt.Sprintf("initialize a default changelog configuration '%s'", config.FileName)),
 		noPrompt:   fs.Bool(noPromptOptName, false, "do not prompt for next version"),
+		version:    fs.Bool(versionOptName, false, "show program version information"),
 	}
 }
 
@@ -74,6 +79,11 @@ func (c Command) Run() error {
 		}
 	}
 
+	if *c.version {
+		fmt.Println(c.b.Version("changelog"))
+		return nil
+	}
+
 	// history is always written to stdout
 	if *c.history {
 		*c.toStdOut = true

internal/cmd/cmd_test.go

@@ -136,6 +136,7 @@ func setup(t *testing.T, repoName string) (c Command, changelogPath string, clea
 		noPrompt:   newBoolPtr(true),
 		toStdOut:   newBoolPtr(false),
 		file:       newStrPtr(filepath.Join(tmp, repoName, dfltChangelogFile)),
+		version:    newBoolPtr(false),
 	}
 
 	cleanup = func() {