fix: add missing version flag parsing

Author: ldez

cmd/nakedret/main.go

@@ -1,7 +1,13 @@
 package main
 
 import (
+	"flag"
+	"fmt"
 	"go/build"
+	"os"
+	"path/filepath"
+	"runtime"
+	"runtime/debug"
 
 	"golang.org/x/tools/go/analysis/singlechecker"
 
@@ -23,8 +29,27 @@ func main() {
 
 	analyzer := nakedret.NakedReturnAnalyzer(nakedRet)
 
+	analyzer.Flags.Init("nakedret", flag.ExitOnError)
+
 	analyzer.Flags.UintVar(&nakedRet.MaxLength, "l", DefaultLines, "maximum number of lines for a naked return function")
 	analyzer.Flags.BoolVar(&nakedRet.SkipTestFiles, "skip-test-files", DefaultSkipTestFiles, "set to true to skip test files")
+	analyzer.Flags.Var(versionFlag{}, "V", "print version and exit")
 
 	singlechecker.Main(analyzer)
 }
+
+type versionFlag struct{}
+
+func (versionFlag) IsBoolFlag() bool { return true }
+func (versionFlag) Get() any         { return nil }
+func (versionFlag) String() string   { return "" }
+func (versionFlag) Set(s string) error {
+	info, ok := debug.ReadBuildInfo()
+	if ok {
+		fmt.Fprintf(os.Stderr, "%s version %s built with %s (%s/%s)\n",
+			filepath.Base(os.Args[0]), info.Main.Version, info.GoVersion, runtime.GOOS, runtime.GOARCH)
+	}
+
+	os.Exit(0)
+	return nil
+}