corrected usage of runtime/debug for version

Author: scott-cotton

ssa_analyzer.go

@@ -16,6 +16,8 @@ package pal
 
 import (
 	"flag"
+	"fmt"
+	"os"
 	"reflect"
 
 	"github.com/go-air/pal/indexing"
@@ -26,6 +28,7 @@ import (
 )
 
 var flagSet = flag.NewFlagSet("pal", flag.ExitOnError)
+var palVersion = flagSet.Bool("V", false, "print out pal version")
 
 type resultType int
 
@@ -51,6 +54,15 @@ func SSAAnalyzer() *analysis.Analyzer {
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
+	//flagSet.Parse(pass.Analyzer.Flags.Args())
+	if *palVersion {
+		v, e := Version()
+		if e != nil {
+			return nil, e
+		}
+		fmt.Printf("%s\n", v)
+		os.Exit(0)
+	}
 	pal, err := ssa2pal.New(pass, indexing.ConstVals())
 	if err != nil {
 		return nil, err

version.go

@@ -17,14 +17,35 @@ package pal
 import (
 	"fmt"
 	"runtime/debug"
+	"strings"
 )
 
+const modPath = "github.com/go-air/pal"
+
+func tryMod(mod *debug.Module) string {
+	if strings.HasPrefix(mod.Path, modPath) {
+		return fmt.Sprintf("%s %s %s",
+			mod.Path, mod.Version, mod.Sum)
+	}
+	return ""
+}
+
 func Version() (string, error) {
 	// something around this will be needed once we put in
 	// place per-package caching.
 	bi, ok := debug.ReadBuildInfo()
 	if !ok {
 		return "", fmt.Errorf("couldn't read build info (are you running go test?)")
 	}
-	return fmt.Sprintf("%s %s %s\n%v\n", bi.Main.Path, bi.Main.Version, bi.Main.Sum, bi), nil
+	s := tryMod(&bi.Main)
+	if s != "" {
+		return s, nil
+	}
+	for _, dep := range bi.Deps {
+		s = tryMod(dep)
+		if s != "" {
+			return s, nil
+		}
+	}
+	return "", fmt.Errorf("could not find %s in debug modules", modPath)
 }