add order and order.groups to cargo,

- pack will now preserve these fields when building archives

Signed-off-by: Ryan Moran <[email protected]>

cargo/config.go

@@ -9,38 +9,49 @@ import (
 )
 
 type Config struct {
-	API       string          `toml:"api" json:"api"`
+	API       string          `toml:"api"       json:"api"`
 	Buildpack ConfigBuildpack `toml:"buildpack" json:"buildpack"`
-	Metadata  ConfigMetadata  `toml:"metadata" json:"metadata"`
-	Stacks    []ConfigStack   `toml:"stacks" json:"stacks"`
+	Metadata  ConfigMetadata  `toml:"metadata"  json:"metadata"`
+	Stacks    []ConfigStack   `toml:"stacks"    json:"stacks"`
+	Order     []ConfigOrder   `toml:"order"     json:"order"`
 }
 
 type ConfigStack struct {
 	ID string `toml:"id" json:"id"`
 }
 
 type ConfigBuildpack struct {
-	ID      string `toml:"id" json:"id"`
-	Name    string `toml:"name" json:"name"`
+	ID      string `toml:"id"      json:"id"`
+	Name    string `toml:"name"    json:"name"`
 	Version string `toml:"version" json:"version"`
 }
 
 type ConfigMetadata struct {
-	IncludeFiles    []string                   `toml:"include_files" json:"include_files"`
+	IncludeFiles    []string                   `toml:"include_files"         json:"include_files"`
 	PrePackage      string                     `toml:"pre_package" json:"pre_package"`
-	DefaultVersions map[string]string          `toml:"default-versions" json:"default-versions"`
-	Dependencies    []ConfigMetadataDependency `toml:"dependencies" json:"dependencies"`
-	Unstructured    map[string]interface{}     `toml:"-" json:"-"`
+	DefaultVersions map[string]string          `toml:"default-versions"      json:"default-versions"`
+	Dependencies    []ConfigMetadataDependency `toml:"dependencies"          json:"dependencies"`
+	Unstructured    map[string]interface{}     `toml:"-"                     json:"-"`
 }
 
 type ConfigMetadataDependency struct {
 	DeprecationDate time.Time `toml:"deprecation_date" json:"deprecation_date"`
-	ID              string    `toml:"id" json:"id"`
-	Name            string    `toml:"name" json:"name"`
-	SHA256          string    `toml:"sha256" json:"sha256"`
-	Stacks          []string  `toml:"stacks" json:"stacks"`
-	URI             string    `toml:"uri" json:"uri"`
-	Version         string    `toml:"version" json:"version"`
+	ID              string    `toml:"id"               json:"id"`
+	Name            string    `toml:"name"             json:"name"`
+	SHA256          string    `toml:"sha256"           json:"sha256"`
+	Stacks          []string  `toml:"stacks"           json:"stacks"`
+	URI             string    `toml:"uri"              json:"uri"`
+	Version         string    `toml:"version"          json:"version"`
+}
+
+type ConfigOrder struct {
+	Group []ConfigOrderGroup `toml:"group" json:"group"`
+}
+
+type ConfigOrderGroup struct {
+	ID       string `toml:"id"       json:"id"`
+	Version  string `toml:"version"  json:"version"`
+	Optional bool   `toml:"optional,omitempty" json:"optional,omitempty"`
 }
 
 func EncodeConfig(writer io.Writer, config Config) error {
@@ -80,10 +91,21 @@ func (m ConfigMetadata) MarshalJSON() ([]byte, error) {
 		metadata[key] = value
 	}
 
-	metadata["include_files"] = m.IncludeFiles
-	metadata["pre_package"] = m.PrePackage
-	metadata["dependencies"] = m.Dependencies
-	metadata["default-versions"] = m.DefaultVersions
+	if len(m.IncludeFiles) > 0 {
+		metadata["include_files"] = m.IncludeFiles
+	}
+
+	if len(m.PrePackage) > 0 {
+		metadata["pre_package"] = m.PrePackage
+	}
+
+	if len(m.Dependencies) > 0 {
+		metadata["dependencies"] = m.Dependencies
+	}
+
+	if len(m.DefaultVersions) > 0 {
+		metadata["default-versions"] = m.DefaultVersions
+	}
 
 	return json.Marshal(metadata)
 }

cargo/config_test.go

@@ -64,6 +64,21 @@ func testConfig(t *testing.T, context spec.G, it spec.S) {
 						"some-dependency": "1.2.x",
 					},
 				},
+				Order: []cargo.ConfigOrder{
+					{
+						Group: []cargo.ConfigOrderGroup{
+							{
+								ID:      "some-dependency",
+								Version: "some-version",
+							},
+							{
+								ID:       "other-dependency",
+								Version:  "other-version",
+								Optional: true,
+							},
+						},
+					},
+				},
 			})
 			Expect(err).NotTo(HaveOccurred())
 			Expect(buffer.String()).To(MatchTOML(`api = "0.2"
@@ -94,6 +109,15 @@ some-dependency = "1.2.x"
 [[stacks]]
   id = "some-stack-id"
 
+[[order]]
+  [[order.group]]
+	  id = "some-dependency"
+		version = "some-version"
+
+  [[order.group]]
+		id = "other-dependency"
+		version = "other-version"
+		optional = true
 `))
 		})
 
@@ -142,6 +166,16 @@ some-dependency = "1.2.x"
 
 [[stacks]]
   id = "some-stack-id"
+
+[[order]]
+  [[order.group]]
+	  id = "some-dependency"
+		version = "some-version"
+
+  [[order.group]]
+		id = "other-dependency"
+		version = "other-version"
+		optional = true
 `)
 
 			var config cargo.Config
@@ -179,6 +213,22 @@ some-dependency = "1.2.x"
 						"some-dependency": "1.2.x",
 					},
 				},
+				Order: []cargo.ConfigOrder{
+					{
+						Group: []cargo.ConfigOrderGroup{
+							{
+								ID:       "some-dependency",
+								Version:  "some-version",
+								Optional: false,
+							},
+							{
+								ID:       "other-dependency",
+								Version:  "other-version",
+								Optional: true,
+							},
+						},
+					},
+				},
 			}))
 		})
 
@@ -193,7 +243,27 @@ some-dependency = "1.2.x"
 	})
 
 	context("ConfigMetadata", func() {
+		context("MarshalJSON", func() {
+			context("when the all fields are empty", func() {
+				it("does not marshal any fields", func() {
+					var metadata cargo.ConfigMetadata
+					output, err := metadata.MarshalJSON()
+					Expect(err).NotTo(HaveOccurred())
+					Expect(string(output)).To(MatchJSON(`{}`))
+				})
+			})
+		})
+
 		context("UnmarshalJSON", func() {
+			context("when the all fields are empty", func() {
+				it("does not unmarshal any fields", func() {
+					var metadata cargo.ConfigMetadata
+					err := metadata.UnmarshalJSON([]byte(`{}`))
+					Expect(err).NotTo(HaveOccurred())
+					Expect(metadata).To(Equal(cargo.ConfigMetadata{}))
+				})
+			})
+
 			context("failure cases", func() {
 				context("metadata field is not a object", func() {
 					it("it returns an error", func() {