From 3d4f2e548c7602c854999deee95262a140dbcbdd Mon Sep 17 00:00:00 2001
From: Dmitry Sigaev <www@sigaev.com>
Date: Tue, 22 Oct 2019 03:06:29 -0700
Subject: [PATCH] plugins: Fix code generation for a conflicting oneof

To reproduce the problem that this pull request fixes:

1. Create x.proto with the following contents:
syntax = "proto3";
message M {
  oneof b {
    bool a = 1;
    bool get_b = 2;  // Conflicts with "oneof b".
  }
}

2. Run the following commands:
go get github.com/gogo/protobuf/protoc-gen-gofast
protoc --gofast_out=. --plugin=$HOME/go/bin/protoc-gen-gofast x.proto
grep M_GetB x.pb.go

3. Output will show that MarshalTo, MarshalToSizedBuffer, Size
   all have an incorrectly named receiver, M_GetB. It needs to be
   M_GetB_ instead:
	//	*M_GetB_
type M_GetB_ struct {
func (*M_GetB_) isM_B() {}
	if x, ok := m.GetB().(*M_GetB_); ok {
		(*M_GetB_)(nil),
func (m *M_GetB) MarshalTo(dAtA []byte) (int, error) {
func (m *M_GetB) MarshalToSizedBuffer(dAtA []byte) (int, error) {
func (m *M_GetB) Size() (n int) {
			m.B = &M_GetB{b}
---
 protoc-gen-gogo/generator/helper.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/protoc-gen-gogo/generator/helper.go b/protoc-gen-gogo/generator/helper.go
index 7091e281cb..e13cd2f731 100644
--- a/protoc-gen-gogo/generator/helper.go
+++ b/protoc-gen-gogo/generator/helper.go
@@ -209,6 +209,9 @@ func (g *Generator) GetOneOfFieldName(message *Descriptor, field *descriptor.Fie
 			return fieldname + "_"
 		}
 	}
+	if field.OneofIndex != nil && "Get"+CamelCase(message.OneofDecl[int(*field.OneofIndex)].GetName()) == fieldname {
+		return fieldname + "_"
+	}
 	return fieldname
 }