Merge pull request #28935 from smarterclayton/avoid_double_encode

Automatic merge from submit-queue

Don't double encode protobuf runtime.Unknown

When using runtime.Object and runtime.RawExtension, passing
runtime.Unknown to protobuf serializer should result in the raw message
being serialized (since all normal protobuf objects are
runtime.Unknown).

Also, avoid setting a content-type when decoding a protobuf object
except when the content appears to be proto.

@wojtek-t

pkg/runtime/serializer/protobuf/protobuf.go

@@ -124,7 +124,7 @@ func (s *Serializer) Decode(originalData []byte, gvk *unversioned.GroupVersionKi
 
 	if intoUnknown, ok := into.(*runtime.Unknown); ok && intoUnknown != nil {
 		*intoUnknown = unk
-		if len(intoUnknown.ContentType) == 0 {
+		if ok, _ := s.RecognizesData(bytes.NewBuffer(unk.Raw)); ok {
 			intoUnknown.ContentType = s.contentType
 		}
 		return intoUnknown, &actual, nil
@@ -167,17 +167,30 @@ func (s *Serializer) Decode(originalData []byte, gvk *unversioned.GroupVersionKi
 
 // Encode serializes the provided object to the given writer.
 func (s *Serializer) Encode(obj runtime.Object, w io.Writer) error {
-	var unk runtime.Unknown
-	kind := obj.GetObjectKind().GroupVersionKind()
-	unk = runtime.Unknown{
-		TypeMeta: runtime.TypeMeta{
-			Kind:       kind.Kind,
-			APIVersion: kind.GroupVersion().String(),
-		},
-	}
-
 	prefixSize := uint64(len(s.prefix))
 
+	var unk runtime.Unknown
+	switch t := obj.(type) {
+	case *runtime.Unknown:
+		estimatedSize := prefixSize + uint64(t.Size())
+		data := make([]byte, estimatedSize)
+		i, err := t.MarshalTo(data[prefixSize:])
+		if err != nil {
+			return err
+		}
+		copy(data, s.prefix)
+		_, err = w.Write(data[:prefixSize+uint64(i)])
+		return err
+	default:
+		kind := obj.GetObjectKind().GroupVersionKind()
+		unk = runtime.Unknown{
+			TypeMeta: runtime.TypeMeta{
+				Kind:       kind.Kind,
+				APIVersion: kind.GroupVersion().String(),
+			},
+		}
+	}
+
 	switch t := obj.(type) {
 	case bufferedMarshaller:
 		// this path performs a single allocation during write but requires the caller to implement

pkg/runtime/serializer/protobuf/protobuf_test.go

@@ -205,7 +205,7 @@ func TestDecode(t *testing.T) {
 		0x0a, 0x15,
 		0x0a, 0x0d, 0x6f, 0x74, 0x68, 0x65, 0x72, 0x2f, 0x76, 0x65, 0x72, 0x73, 0x69, 0x6f, 0x6e, // apiversion
 		0x12, 0x04, 0x74, 0x65, 0x73, 0x74, // kind
-		0x12, 0x03, 0x01, 0x02, 0x03, // data
+		0x12, 0x07, 0x6b, 0x38, 0x73, 0x00, 0x01, 0x02, 0x03, // data
 		0x1a, 0x00, // content-type
 		0x22, 0x00, // content-encoding
 	}
@@ -227,8 +227,7 @@ func TestDecode(t *testing.T) {
 		},
 		{
 			obj: &runtime.Unknown{
-				ContentType: "application/protobuf",
-				Raw:         []byte{},
+				Raw: []byte{},
 			},
 			data: wire1,
 		},
@@ -238,8 +237,9 @@ func TestDecode(t *testing.T) {
 					APIVersion: "other/version",
 					Kind:       "test",
 				},
+				// content type is set because the prefix matches the content
 				ContentType: "application/protobuf",
-				Raw:         []byte{0x01, 0x02, 0x03},
+				Raw:         []byte{0x6b, 0x38, 0x73, 0x00, 0x01, 0x02, 0x03},
 			},
 			data: wire2,
 		},