Remove top-level version from BOM

resolves: buildpacks#357

Signed-off-by: Yael Harel <yharel@vmware.com>

builder.go

@@ -1,15 +1,17 @@
 package lifecycle
 
 import (
+	"fmt"
+	"github.com/BurntSushi/toml"
+	"github.com/buildpacks/lifecycle/api"
+
 	"io/ioutil"
 	"log"
 	"os"
 	"os/exec"
 	"path/filepath"
 	"sort"
 
-	"github.com/BurntSushi/toml"
-
 	"github.com/buildpacks/lifecycle/launch"
 	"github.com/buildpacks/lifecycle/layers"
 )
@@ -19,6 +21,7 @@ type Builder struct {
 	LayersDir     string
 	PlatformDir   string
 	BuildpacksDir string
+	PlatformAPI   *api.Version
 	Env           BuildEnv
 	Group         BuildpackGroup
 	Plan          BuildPlan
@@ -143,6 +146,18 @@ func (b *Builder) Build() (*BuildMetadata, error) {
 		labels = append(labels, launch.Labels...)
 	}
 
+   	comparisonVersion := api.MustParse("0.4")
+   	if b.PlatformAPI.Compare(comparisonVersion) < 0 {
+		//plaformApiVersion is less than comparisonVersion
+   		for _, bomEntry := range bom {
+			bomEntry.convertMetadataToVersion()
+		}
+	} else {
+		for _, bomEntry := range bom {
+			bomEntry.convertVersionToMetadata()
+		}
+	}
+
 	return &BuildMetadata{
 		BOM:        bom,
 		Buildpacks: b.Group.Group,
@@ -191,6 +206,23 @@ func (p buildpackPlan) has(entry BuildPlanEntry) bool {
 	return false
 }
 
+func (bom *BOMEntry) convertMetadataToVersion() {
+	if version, ok := bom.Metadata["version"]; ok {
+		bom.Version = fmt.Sprintf("%v", version)
+		delete(bom.Metadata, "version")
+	}
+}
+
+func (bom *BOMEntry) convertVersionToMetadata() {
+	if bom.Version != "" {
+		if bom.Metadata == nil {
+			bom.Metadata = make(map[string]interface{})
+		}
+		bom.Metadata["version"] = bom.Version
+		bom.Version = ""
+	}
+}
+
 func setupEnv(env BuildEnv, layersDir string) error {
 	if err := eachDir(layersDir, func(path string) error {
 		if !isBuild(path + ".toml") {

builder_test.go

@@ -3,6 +3,7 @@ package lifecycle_test
 import (
 	"bytes"
 	"fmt"
+	"github.com/buildpacks/lifecycle/api"
 	"io"
 	"io/ioutil"
 	"log"
@@ -66,6 +67,7 @@ func testBuilder(t *testing.T, when spec.G, it spec.S) {
 			LayersDir:     layersDir,
 			PlatformDir:   platformDir,
 			BuildpacksDir: buildpacksDir,
+			PlatformAPI:   api.MustParse("0.3"),
 			Env:           env,
 			Group: lifecycle.BuildpackGroup{
 				Group: []lifecycle.Buildpack{

cmd/lifecycle/builder.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"errors"
+	"github.com/buildpacks/lifecycle/api"
 	"log"
 	"os"
 
@@ -27,6 +28,7 @@ type buildArgs struct {
 	layersDir     string
 	appDir        string
 	platformDir   string
+	platformAPI   string
 }
 
 func (b *buildCmd) Init() {
@@ -70,6 +72,7 @@ func (ba buildArgs) build(group lifecycle.BuildpackGroup, plan lifecycle.BuildPl
 		LayersDir:     ba.layersDir,
 		PlatformDir:   ba.platformDir,
 		BuildpacksDir: ba.buildpacksDir,
+		PlatformAPI:   api.MustParse(ba.platformAPI),
 		Env:           env.NewBuildEnv(os.Environ()),
 		Group:         group,
 		Plan:          plan,

cmd/lifecycle/main.go

@@ -25,7 +25,7 @@ func main() {
 	case "restorer":
 		cmd.Run(&restoreCmd{}, false)
 	case "builder":
-		cmd.Run(&buildCmd{}, false)
+		cmd.Run(&buildCmd{buildArgs: buildArgs{platformAPI: platformAPI}}, false)
 	case "exporter":
 		cmd.Run(&exportCmd{exportArgs: exportArgs{platformAPI: platformAPI}}, false)
 	case "rebaser":

detector.go

@@ -43,7 +43,7 @@ func (be BuildPlanEntry) noOpt() BuildPlanEntry {
 
 type Require struct {
 	Name     string                 `toml:"name" json:"name"`
-	Version  string                 `toml:"version" json:"version"`
+	Version  string                 `toml:"version,omitempty" json:"version,omitempty"`
 	Metadata map[string]interface{} `toml:"metadata" json:"metadata"`
 }