Makefile

@@ -79,6 +79,7 @@ $(BIN)/protogen:
 
 protoc-test: protoc $(BIN)/protogen
 	@$(PROTOC_DIR)/bin/protoc \
+			--go_out=. --go_opt=paths=source_relative \
 			--plugin=protoc-gen-go-frostfs=$(abspath $(BIN)/protogen) \
 			--go-frostfs_opt=Mutil/proto/test/test.proto=git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/util/proto/test/custom \
 			--go-frostfs_opt=module=git.frostfs.info/TrueCloudLab/frostfs-api-go/v2 \

util/proto/marshal_test.go

@@ -49,6 +49,8 @@ func TestStableMarshalSingle(t *testing.T) {
 		{name: "fixed32", input: &generated.Primitives{FieldK: nonZero[uint32]()}},
 		{name: "enum, positive", input: &generated.Primitives{FieldH: generated.Primitives_POSITIVE}},
 		{name: "enum, negative", input: &generated.Primitives{FieldH: generated.Primitives_NEGATIVE}},
+		{name: "oneof, first", input: &generated.Primitives{FieldM: &generated.Primitives_FieldMa{FieldMa: []byte{4, 2}}}},
+		{name: "oneof, second", input: &generated.Primitives{FieldM: &generated.Primitives_FieldMe{FieldMe: nonZero[uint32]()}}},
 	}
 	for _, tc := range marshalCases {
 		t.Run(tc.name, func(t *testing.T) {
@@ -97,6 +99,9 @@ func primitivesEqual(t *testing.T, a *generated.Primitives, b *test.Primitives)
 	require.Equal(t, a.FieldJ, b.FieldJ)
 	require.Equal(t, a.FieldK, b.FieldK)
 	require.EqualValues(t, a.FieldH, b.FieldH)
+	require.Equal(t, a.GetFieldMa(), b.GetFieldMa())
+	require.Equal(t, a.GetFieldMe(), b.GetFieldMe())
+	require.Equal(t, a.GetFieldAux().GetInnerField(), b.GetFieldAux().GetInnerField())
 }
 
 func repPrimitivesEqual(t *testing.T, a *generated.RepPrimitives, b *test.RepPrimitives) {

util/proto/test/test.proto

@@ -22,6 +22,14 @@ message Primitives {
     NEGATIVE = -1;
   }
   SomeEnum field_h = 300;
+
+  message Aux { uint32 inner_field = 1; }
+
+  oneof field_m {
+    bytes field_ma = 401;
+    uint32 field_me = 402;
+    Aux field_aux = 403;
+  }
 }
 
 message RepPrimitives {

util/protogen/internalgengo/file.go

@@ -126,29 +126,24 @@ func emitOneofGettersSetters(g *protogen.GeneratedFile, msg *protogen.Message, f
 	// For some reason protoc generates different code for oneof message/non-message fields:
 	// 1. For message we have 2 level struct wrapping and setters use inner type.
 	// 2. For other types we also have 2 level wrapping, but setters use outer type.
+	ft := fieldType(g, ff)
+
+	g.P("func (x *", msg.GoIdent.GoName, ") Get", ff.GoName, "() ", ft, " {")
+	g.P("if xx, ok := x.Get", ff.Oneof.GoName, "().(*", ff.GoIdent, "); ok { return xx.", ff.GoName, " }")
+	g.P("return ", fieldDefaultValue(ff))
+	g.P("}")
+
 	if ff.Desc.Kind() == protoreflect.MessageKind {
-		ft := fieldType(g, ff)
-
-		g.P("func (x *", msg.GoIdent.GoName, ") Get", ff.GoName, "() ", ft, " {")
-		g.P("if xx, ok := x.Get", ff.Oneof.GoName, "().(*", ff.GoIdent, "); ok { return xx.", ff.GoName, " }")
-		g.P("return nil")
-		g.P("}")
-
 		g.P("func (x *", msg.GoIdent.GoName, ") Set", ff.GoName, "(v ", ft, ") {")
 		g.P("x.", ff.Oneof.GoName, " = &", ff.GoIdent, "{", ff.GoName, ": v}")
 		g.P("}")
 	} else {
-		g.P("func (x *", msg.GoIdent.GoName, ") Get", ff.GoName, "() *", ff.GoIdent, " {")
-		g.P("if xx, ok := x.Get", ff.Oneof.GoName, "().(*", ff.GoIdent, "); ok { return xx }")
-		g.P("return nil")
-		g.P("}")
-
 		g.P("func (x *", msg.GoIdent.GoName, ") Set", ff.GoName, "(v *", ff.GoIdent, ") {")
 		g.P("x.", ff.Oneof.GoName, " = v")
 		g.P("}")
 
 		ft := fieldType(g, ff)
-		emitGetterSetter(g, ff.GoIdent.GoName, ff.GoName, ft.String(), "nil")
+		emitGetterSetter(g, ff.GoIdent.GoName, ff.GoName, ft.String(), fieldDefaultValue(ff))
 	}
 }
 

util/protogen/internalgengo/json.go

@@ -159,8 +159,6 @@ func emitJSONMarshal(g *protogen.GeneratedFile, msg *protogen.Message) {
 				g.P("case *", ff.GoIdent, ":")
 				emitJSONFieldWrite(g, ff, "xx", i == 0)
 			}
-			g.P("default:")
-			g.P(`out.RawString("null")`)
 			g.P("}")
 			continue
 		}

util/protogen/main.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"flag"
-	"fmt"
-	"os"
 
 	"git.frostfs.info/TrueCloudLab/frostfs-api-go/v2/util/protogen/internalgengo"
 	"google.golang.org/protobuf/compiler/protogen"
@@ -12,18 +10,10 @@ import (
 func main() {
 	var flags flag.FlagSet
 	genFuzz := flags.Bool("fuzz", false, "generate fuzz tests")
-	yamlConfigPath := flags.String("config", "", "path to the configuration")
 
 	protogen.Options{
 		ParamFunc: flags.Set,
 	}.Run(func(gen *protogen.Plugin) error {
-		if *yamlConfigPath != "" {
-			s, e := os.Getwd()
-			fmt.Fprintln(os.Stderr, s, e)
-			data, err := os.ReadFile(*yamlConfigPath)
-			fmt.Fprintln(os.Stderr, string(data), err)
-		}
-
 		for _, f := range gen.Files {
 			if f.Generate {
 				internalgengo.GenerateFile(gen, f)