Initial receipt type

internal/index/indexscanner/scanner.go

@@ -86,38 +86,53 @@ func LoadPluginByName(pluginsDir, pluginName string) (index.Plugin, error) {
 // ReadPluginFromFile loads a file from the FS. When plugin file not found, it
 // returns an error that can be checked with os.IsNotExist.
 func ReadPluginFromFile(path string) (index.Plugin, error) {
-	f, err := os.Open(path)
-	if os.IsNotExist(err) {
-		// TODO(ahmetb): we should use go1.13+ errors.Is construct at call sites to evaluate if an error is os.IsNotExist
-		return index.Plugin{}, err
-	} else if err != nil {
-		return index.Plugin{}, errors.Wrap(err, "failed to open index file")
+	var plugin index.Plugin
+	err := readFromFile(path, &plugin)
+	if err != nil {
+		return plugin, err
 	}
-	return ReadPlugin(f)
+	return plugin, errors.Wrap(validation.ValidatePlugin(plugin.Name, plugin), "plugin manifest validation error")
 }
 
 func ReadPlugin(f io.ReadCloser) (index.Plugin, error) {
-	defer f.Close()
-	p, err := DecodePluginFile(f)
+	var plugin index.Plugin
+	err := decodeFile(f, &plugin)
 	if err != nil {
-		return p, errors.Wrap(err, "failed to decode plugin manifest")
+		return plugin, errors.Wrap(err, "failed to decode plugin manifest")
 	}
-	return p, errors.Wrap(validation.ValidatePlugin(p.Name, p), "plugin manifest validation error")
+	return plugin, errors.Wrap(validation.ValidatePlugin(plugin.Name, plugin), "plugin manifest validation error")
 }
 
-// DecodePluginFile tries to decodes a plugin manifest from r.
-func DecodePluginFile(r io.Reader) (index.Plugin, error) {
-	var plugin index.Plugin
+// ReadReceiptFromFile loads a file from the FS. When receipt file not found, it
+// returns an error that can be checked with os.IsNotExist.
+func ReadReceiptFromFile(path string) (index.Receipt, error) {
+	var receipt index.Receipt
+	err := readFromFile(path, &receipt)
+	return receipt, err
+}
+
+// readFromFile loads a file from the FS into the provided object.
+func readFromFile(path string, as interface{}) error {
+	f, err := os.Open(path)
+	if err != nil {
+		return err
+	}
+	err = decodeFile(f, &as)
+	return errors.Wrap(err, "failed to parse yaml file")
+}
+
+// decodeFile tries to decode a plugin/receipt
+func decodeFile(r io.ReadCloser, as interface{}) error {
+	defer r.Close()
 	b, err := ioutil.ReadAll(r)
 	if err != nil {
-		return plugin, err
+		return err
 	}
 
 	// TODO(ahmetb): when we have a stable API that won't add new fields,
 	// we can consider failing on unknown fields. Currently, disabling due to
 	// incremental field additions to plugin manifests independently from the
 	// installed version of krew.
 	// yaml.UnmarshalStrict()
-	err = yaml.Unmarshal(b, &plugin)
-	return plugin, err
+	return yaml.Unmarshal(b, &as)
 }

internal/installation/receipt/receipt.go

@@ -24,7 +24,7 @@ import (
 	"sigs.k8s.io/krew/pkg/index"
 )
 
-// Store saves the given plugin at the destination.
+// Store saves the given plugin receipt at the destination.
 // The caller has to ensure that the destination directory exists.
 func Store(plugin index.Plugin, dest string) error {
 	yamlBytes, err := yaml.Marshal(plugin)
@@ -38,6 +38,6 @@ func Store(plugin index.Plugin, dest string) error {
 
 // Load reads the plugin receipt at the specified destination.
 // If not found, it returns os.IsNotExist error.
-func Load(path string) (index.Plugin, error) {
-	return indexscanner.ReadPluginFromFile(path)
+func Load(path string) (index.Receipt, error) {
+	return indexscanner.ReadReceiptFromFile(path)
 }

internal/installation/receipt/receipt_test.go

@@ -22,6 +22,7 @@ import (
 
 	"sigs.k8s.io/krew/internal/index/indexscanner"
 	"sigs.k8s.io/krew/internal/testutil"
+	"sigs.k8s.io/krew/pkg/index"
 )
 
 func TestStore(t *testing.T) {
@@ -58,7 +59,8 @@ func TestLoad(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if diff := cmp.Diff(&gotPlugin, &testPlugin); diff != "" {
+	testPluginReceipt := index.Receipt{Plugin: testPlugin}
+	if diff := cmp.Diff(&gotPlugin, &testPluginReceipt); diff != "" {
 		t.Fatal(diff)
 	}
 }

internal/installation/util_test.go

@@ -65,7 +65,7 @@ func TestListInstalledPlugins(t *testing.T) {
 			defer cleanup()
 
 			for _, plugin := range test.plugins {
-				tempDir.WritePlugin(plugin.Name+constants.ManifestExtension, plugin)
+				tempDir.WriteYAML(plugin.Name+constants.ManifestExtension, plugin)
 			}
 
 			actual, err := ListInstalledPlugins(tempDir.Root())

internal/testutil/tempdir.go

@@ -23,8 +23,6 @@ import (
 	"testing"
 
 	"sigs.k8s.io/yaml"
-
-	"sigs.k8s.io/krew/pkg/index"
 )
 
 type TempDir struct {
@@ -77,11 +75,11 @@ func (td *TempDir) Write(file string, content []byte) *TempDir {
 	return td
 }
 
-func (td *TempDir) WritePlugin(file string, plugin index.Plugin) *TempDir {
+func (td *TempDir) WriteYAML(file string, obj interface{}) *TempDir {
 	td.t.Helper()
-	content, err := yaml.Marshal(plugin)
+	content, err := yaml.Marshal(obj)
 	if err != nil {
-		td.t.Fatalf("cannot marshal plugin: %s", err)
+		td.t.Fatalf("cannot marshal obj: %s", err)
 	}
 	return td.Write(file, content)
 }

pkg/index/types.go

@@ -58,3 +58,8 @@ type FileOperation struct {
 	From string `json:"from,omitempty"`
 	To   string `json:"to,omitempty"`
 }
+
+// Receipt describes a plugin receipt file.
+type Receipt struct {
+	Plugin `json:",inline" yaml:",inline"`
+}