chore: add support for map[string]interface{}

For siderolabs/talos#6057

Signed-off-by: Dmitriy Matrenichev <dmitry.matrenichev@siderolabs.com>

marshal.go

@@ -16,6 +16,7 @@ import (
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/types/known/durationpb"
+	"google.golang.org/protobuf/types/known/structpb"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
@@ -253,6 +254,22 @@ func (m *marshaller) encodeValue(num protowire.Number, val reflect.Value) {
 
 func (m *marshaller) tryEncodePredefined(num protowire.Number, val reflect.Value) bool {
 	switch val.Type() {
+	case typeMapInterface:
+		v := val.Interface().(map[string]interface{}) //nolint:errcheck,forcetypeassert
+
+		val, err := structpb.NewStruct(v)
+		if err != nil {
+			panic(fmt.Errorf("failed to create structpb.Struct: %w", err))
+		}
+
+		encoded, err := proto.Marshal(val)
+		if err != nil {
+			panic(err)
+		}
+
+		putTag(m, num, protowire.BytesType)
+		putBytes(m, encoded)
+
 	case typeDuration:
 		d := val.Interface().(time.Duration) //nolint:errcheck,forcetypeassert
 		duration := durationpb.New(d)

marshal_test.go

@@ -592,3 +592,17 @@ func TestIncorrectCustomEncoders(t *testing.T) {
 		)
 	})
 }
+
+func TestMarshalMapInterface(t *testing.T) {
+	// json decodes numeric values as float64s
+	// json decoder do not support slices
+	testEncodeDecode(OneFieldStruct[map[string]interface{}]{map[string]interface{}{
+		"a": 1.0,
+		"b": "2",
+		"c": true,
+		"e": map[string]interface{}{
+			"a": 1.0,
+			"g": 10.10,
+		},
+	}})(t)
+}

predefined_types.go

@@ -24,18 +24,19 @@ type (
 )
 
 var (
-	typeFixedU32  = typeOf[FixedU32]()
-	typeFixedU64  = typeOf[FixedU64]()
-	typeFixedS32  = typeOf[FixedS32]()
-	typeFixedS64  = typeOf[FixedS64]()
-	typeTime      = typeOf[time.Time]()
-	typeDuration  = typeOf[time.Duration]()
-	typeFixedU32s = reflect.SliceOf(typeFixedU32)
-	typeFixedU64s = reflect.SliceOf(typeFixedU64)
-	typeFixedS32s = reflect.SliceOf(typeFixedS32)
-	typeFixedS64s = reflect.SliceOf(typeFixedS64)
-	typeDurations = reflect.SliceOf(typeDuration)
-	typeByte      = typeOf[byte]()
+	typeFixedU32     = typeOf[FixedU32]()
+	typeFixedU64     = typeOf[FixedU64]()
+	typeFixedS32     = typeOf[FixedS32]()
+	typeFixedS64     = typeOf[FixedS64]()
+	typeTime         = typeOf[time.Time]()
+	typeDuration     = typeOf[time.Duration]()
+	typeMapInterface = typeOf[map[string]interface{}]()
+	typeFixedU32s    = reflect.SliceOf(typeFixedU32)
+	typeFixedU64s    = reflect.SliceOf(typeFixedU64)
+	typeFixedS32s    = reflect.SliceOf(typeFixedS32)
+	typeFixedS64s    = reflect.SliceOf(typeFixedS64)
+	typeDurations    = reflect.SliceOf(typeDuration)
+	typeByte         = typeOf[byte]()
 )
 
 func typeOf[T any]() reflect.Type {

slice_test.go

@@ -205,6 +205,8 @@ func TestSmallIntegers(t *testing.T) {
 
 	type customByte byte
 
+	type customSlice []byte
+
 	type customType struct {
 		Int16      int16      `protobuf:"1"`
 		Uint16     uint16     `protobuf:"3"`
@@ -243,6 +245,10 @@ func TestSmallIntegers(t *testing.T) {
 			"slice of uint16 type should be encoded in 'fixed32' form",
 			testEncodeDecodeWrapped([]uint16{1, 0xFFFF, 3}, encodedUint16s),
 		},
+		{
+			"customSlice should be encoded in 'bytes' form",
+			testEncodeDecodeWrapped(customSlice{1, 0xFF, 3}, encodedBytes),
+		},
 		{
 			"customType should be encoded in 'fixed32' form",
 			testEncodeDecodeWrapped(customType{

unmarshal.go

@@ -13,6 +13,7 @@ import (
 	"google.golang.org/protobuf/encoding/protowire"
 	"google.golang.org/protobuf/proto"
 	"google.golang.org/protobuf/types/known/durationpb"
+	"google.golang.org/protobuf/types/known/structpb"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
@@ -348,7 +349,7 @@ func instantiate(dst reflect.Value) error {
 	return nil
 }
 
-//nolint:cyclop
+//nolint:cyclop,gocyclo
 func unmarshalBytes(dst reflect.Value, value complexValue) (err error) {
 	defer func() {
 		if err != nil {
@@ -389,6 +390,17 @@ func unmarshalBytes(dst reflect.Value, value complexValue) (err error) {
 
 		dst.Set(reflect.ValueOf(result.AsDuration()))
 
+		return nil
+	case typeMapInterface:
+		var result structpb.Struct
+
+		err = proto.Unmarshal(bytes, &result)
+		if err != nil {
+			return err
+		}
+
+		dst.Set(reflect.ValueOf(result.AsMap()))
+
 		return nil
 	}