find main packages and print them

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"bytes"
 	"fmt"
+	"go/build"
 	"io"
 	"io/ioutil"
 	"log"
@@ -14,12 +15,14 @@ import (
 func main() {
 	log.SetFlags(log.Ldate | log.Ltime | log.Lshortfile)
 	binDirs := []string{}
+	srcDirs := []string{}
 	for _, env := range os.Environ() {
 		if strings.HasPrefix(env, "GOPATH=") {
 			i := strings.Index(env, "=")
 			paths := filepath.SplitList(env[i+1:])
 			for _, path := range paths {
 				binDirs = append(binDirs, filepath.Join(path, "bin"))
+				srcDirs = append(srcDirs, filepath.Join(path, "src"))
 			}
 		}
 	}
@@ -46,7 +49,8 @@ func main() {
 		}
 	}
 
-	execs := []string{}
+	execs := map[string][]string{}
+	execNames := []string{}
 	buf := &bytes.Buffer{}
 	for _, name := range files {
 		buf.Reset()
@@ -78,16 +82,55 @@ func main() {
 		}
 		for _, b := range execPatterns {
 			if bytes.Equal(buf.Bytes(), b) {
-				execs = append(execs, name)
+				_, en := filepath.Split(name)
+				if _, ok := execs[en]; !ok {
+					execs[en] = []string{}
+					execNames = append(execNames, en)
+				}
 			}
 		}
 	}
 
-	for _, exec := range execs {
-		fmt.Println(exec)
+	for _, srcDir := range srcDirs {
+		filepath.Walk(
+			srcDir,
+			func(path string, info os.FileInfo, err error) error {
+				if !info.IsDir() {
+					return nil
+				}
+				if strings.HasSuffix(path, ".git") ||
+					strings.HasSuffix(path, ".hg") {
+					return filepath.SkipDir
+				}
+				potentialPackage := strings.TrimPrefix(path, srcDir+"/")
+
+				pkg, err := build.Import(potentialPackage, srcDir, 0)
+				if err != nil {
+					return nil
+				}
+				if pkg.Name != "main" {
+					return nil
+				}
+				_, en := filepath.Split(pkg.ImportPath)
+				if _, ok := execs[en]; ok {
+					execs[en] = append(execs[en], pkg.ImportPath)
+				}
+				return nil
+			},
+		)
+	}
+
+	for _, name := range execNames {
+		if len(execs[name]) > 0 {
+			fmt.Println(name)
+			for _, potential := range execs[name] {
+				fmt.Printf("\t%s\n", potential)
+			}
+		}
 	}
 }
 
+// Exists emits true if path exists, false otherwise
 func exists(path string) bool {
 	if _, err := os.Stat(path); err != nil {
 		return false