Include new packages in output, performance tweaks

Favor time over space by using more maps and less appends.

Include new packages in the output so that new services will also be
deployed

main.go

@@ -9,6 +9,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"sort"
 	"strings"
 )
 
@@ -26,7 +27,7 @@ more of its dependacies have been modified`)
 }
 
 var (
-	packages      []string                  // the packages to check for taint
+	packages      map[string]struct{}       // the packages to check for taint
 	changedDirs   map[string]struct{}       // the directories which contain modified files
 	cache         map[string]*build.Package // a map[>package name>]<build.Package> to skip repeat lookups
 	gitDirPtr     *string                   // the git directory to check for changes
@@ -37,6 +38,7 @@ var (
 func init() {
 	cache = make(map[string]*build.Package)
 	changedDirs = make(map[string]struct{})
+	packages = make(map[string]struct{})
 }
 
 func main() {
@@ -70,16 +72,27 @@ func main() {
 	if err != nil {
 		log.Fatal(err)
 	}
-	for _, v := range packages {
+	output := make(map[string]struct{})
+	for k := range packages {
 		// get all the deps
-		deps, err := findDeps(v, cwd)
+		deps, err := findDeps(k, cwd)
 		if err != nil {
 			log.Fatal(err)
 		}
 		if hasChanges(deps) {
-			fmt.Println(v)
+			output[k] = struct{}{}
 		}
 	}
+	// finally to make it all pretty, sort it in a slice
+	prettyOutput := make([]string, 0, len(output))
+	for k := range output {
+		prettyOutput = append(prettyOutput, k)
+	}
+	if len(prettyOutput) == 0 {
+		return
+	}
+	sort.Strings(prettyOutput)
+	fmt.Println(strings.Join(prettyOutput, "\n"))
 }
 
 // checks to see if any of the deps have the same suffix as anything in the changedDirs
@@ -98,7 +111,7 @@ func hasChanges(deps []string) bool {
 func readPackages() {
 	scanner := bufio.NewScanner(os.Stdin)
 	for scanner.Scan() {
-		packages = append(packages, scanner.Text())
+		packages[scanner.Text()] = struct{}{}
 	}
 	if err := scanner.Err(); err != nil {
 		log.Fatal(err)

packages.go

@@ -6,7 +6,7 @@ import (
 )
 
 type context struct {
-	soFar map[string]bool
+	soFar map[string]struct{}
 	ctx   build.Context
 }
 
@@ -28,11 +28,11 @@ func (c *context) find(name, dir string) (err error) {
 	}
 
 	if name != "." {
-		c.soFar[pkg.ImportPath] = true
+		c.soFar[pkg.ImportPath] = struct{}{}
 	}
 	imports := pkg.Imports
 	for _, imp := range imports {
-		if !c.soFar[imp] {
+		if _, ok := c.soFar[imp]; !ok {
 			if err := c.find(imp, pkg.Dir); err != nil {
 				return err
 			}
@@ -45,17 +45,15 @@ func findDeps(name, dir string) ([]string, error) {
 	ctx := build.Default
 
 	c := &context{
-		soFar: make(map[string]bool),
+		soFar: make(map[string]struct{}),
 		ctx:   ctx,
 	}
 	if err := c.find(name, dir); err != nil {
 		return nil, err
 	}
 	deps := make([]string, 0, len(c.soFar))
 	for p := range c.soFar {
-		if p != name {
-			deps = append(deps, p)
-		}
+		deps = append(deps, p)
 	}
 	sort.Strings(deps)
 	return deps, nil