如何访问proto.EnumValueOptions扩展值

Question

I have similar setup as bellow, how can I access my extension values from XYZ enum using "github.com/golang/protobuf/proto"?

  extend google.protobuf.EnumValueOptions {
    Details meta = 50001;
  }

  message Details {
    string description = 1;
  }

  enum MyEnum {
    MY_ENUM_UNSPECIFIED = 0;
    XYZ = 1 [deprecated=true, (meta) = {description: "lorem ipsum"}];
  }

I'm aware of proto.GetExtension(proto.Message, proto.ExtensionDesc), however I'm cannot figure out how it can be used for the enum...

Answer 1

Bit late but I've just run into the same; you can do it like this:

fd, _ := descriptor.ForMessage(&pb.Details{})
for _, e := range fd.EnumType {
    if e.GetName() == "MyEnum" {
        for _, v := range e.Value {
            ext, err := proto.GetExtension(v.Options, pb.E_Meta)
            if err == nil {
                details := ext.(*pb.Details)
                // do stuff with details
            }
        }
    }
}

There might be a more direct way of getting the enum descriptor, although I haven't managed after a bit of wrangling.