json tags not set for oneof fields

[tyleradams]

A struct like

message A {
  optional string e = 3;
  oneof b {
    string c = 1;
    string d = 2;
  }
}

Generates the following go code

type A struct {
  E *E `protobuf:"bytes,3,opt,name=e" json:"e,omitempty"`
  // Types that are valid to be assigned to B
  //   * B_C
  //   * B_D
  B   isA_B `protobuf_oneof:"value"`
}
...
type struct {
  C string `protobuf:"bytes,1,opt,name=c,oneof"`
}

type struct {
  D string `protobuf:"bytes,2,opt,name=d,oneof"`
}
...

The oneof field structs should also have json go tags so they can serialize to JSON correctly.

[dsymonds]

It's working correctly. The correct way to serialise a protocol buffer to JSON is to use the jsonpb package, which doesn't use the json struct field tags.

[marwan-at-work]

If that's the case, I'm not sure why there are json:"<fieldName>" tags in all generated Go struct fields except oneof?

It's also worth mentioning that many protobuf-generated Go structs are used in contexts where they are automatically serialized with encoding/json without the programmer having access to change that to jsonpb.

One way to solve it is to have protoc-gen-go implement the json.Marshaler interface and uses jsonpb under the hood to ensure that anyone using encoding/json would get the correct outcome. Would that work?

Thanks