Implement message type, merge, autoboxing

go/protomodule/BUILD

@@ -3,10 +3,12 @@ load("@io_bazel_rules_go//go:def.bzl", "go_library", "go_test")
 go_library(
     name = "protomodule",
     srcs = [
+        "merge.go",
         "protomodule.go",
         "protomodule_enum.go",
         "protomodule_list.go",
         "protomodule_map.go",
+        "protomodule_message.go",
         "protomodule_message_type.go",
         "protomodule_package.go",
         "type_conversions.go",
@@ -24,19 +26,28 @@ go_library(
         "@org_golang_google_protobuf//proto",
         "@org_golang_google_protobuf//reflect/protoreflect",
         "@org_golang_google_protobuf//reflect/protoregistry",
+        "@org_golang_google_protobuf//types/dynamicpb",
         "@org_golang_google_protobuf//types/known/anypb",
+        "@org_golang_google_protobuf//types/known/wrapperspb",
     ],
 )
 
 go_test(
     name = "protomodule_test",
-    srcs = ["protomodule_test.go"],
+    srcs = [
+        "protomodule_test.go",
+    ],
     embed = [":protomodule"],
     deps = [
+        "//:skycfg",
+        "//internal/go/skycfg",
         "//internal/testdata/test_proto:test_proto_go_proto",
         "@net_starlark_go//resolve",
         "@net_starlark_go//starlark",
         "@net_starlark_go//starlarkstruct",
+        "@net_starlark_go//syntax",
         "@org_golang_google_protobuf//reflect/protoregistry",
+        "@org_golang_google_protobuf//types/descriptorpb",
+        "@org_golang_google_protobuf//types/known/anypb",
     ],
 )

go/protomodule/merge.go

@@ -0,0 +1,97 @@
+// Copyright 2020 The Skycfg Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+package protomodule
+
+import (
+	"fmt"
+
+	"go.starlark.net/starlark"
+)
+
+// Implements proto.merge merging src into dst, returning merged value
+func mergeField(dst, src starlark.Value) (starlark.Value, error) {
+	if dst == nil {
+		return src, nil
+	}
+	if src == nil {
+		return dst, nil
+	}
+
+	if dst.Type() != src.Type() {
+		return nil, mergeError(dst, src)
+	}
+
+	switch dst := dst.(type) {
+	case *protoRepeated:
+		if src, ok := src.(*protoRepeated); ok {
+			newList := newProtoRepeated(dst.fieldDesc)
+
+			err := newList.Extend(dst)
+			if err != nil {
+				return nil, err
+			}
+
+			err = newList.Extend(src)
+			if err != nil {
+				return nil, err
+			}
+
+			return newList, nil
+		}
+		return nil, mergeError(dst, src)
+	case *protoMap:
+		if src, ok := src.(*protoMap); ok {
+			newMap := newProtoMap(dst.mapKey, dst.mapValue)
+
+			for _, item := range dst.Items() {
+				err := newMap.SetKey(item[0], item[1])
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			for _, item := range src.Items() {
+				err := newMap.SetKey(item[0], item[1])
+				if err != nil {
+					return nil, err
+				}
+			}
+
+			return newMap, nil
+		}
+		return nil, mergeError(dst, src)
+	case *protoMessage:
+		if src, ok := src.(*protoMessage); ok {
+			newMessage, err := NewMessage(dst.msg)
+			if err != nil {
+				return nil, err
+			}
+
+			newMessage.Merge(dst)
+			newMessage.Merge(src)
+
+			return newMessage, nil
+		}
+		return nil, mergeError(dst, src)
+	default:
+		return src, nil
+	}
+}
+
+func mergeError(dst, src starlark.Value) error {
+	return fmt.Errorf("MergeError: Cannot merge protobufs of different types: Merge(%s, %s)", dst.Type(), src.Type())
+}