Feature request: xxxtags (moretags for XXX_* fields)

[oceanful]

As requested in https://groups.google.com/forum/#!topic/gogoprotobuf/xmFnqAS6MIc

it would very useful to be able to set struct tags on the XXX_* fields, so that they can be ignored when used for other serialization formats. (For example, the json:"_" struct tag is already added to those fields by default.)

type Station struct {
	AlignmentId          string   `protobuf:"bytes,1,opt,name=alignment_id,json=alignmentId,proto3" json:"alignment_id,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-"`
	XXX_sizecache        int32    `json:"-"`
}

Would it be possible to have a message-level option called xxxtags, and a file-level analog xxxtags_all?

message Station {
  option (gogoproto.xxxtags) = "firestore:\"-\"";

  string alignment_id = 1;
};

to generate:

type Station struct {
	AlignmentId          string   `protobuf:"bytes,1,opt,name=alignment_id,json=alignmentId,proto3" json:"alignment_id,omitempty"`
	XXX_NoUnkeyedLiteral struct{} `json:"-" firestore:"-"`
	XXX_sizecache        int32    `json:"-" firestore:"-"`
}

[ivybridge-3c33]

how to ?

[oceanful]

Hmm ... one way could be to do something like what is done for moretags

protobuf/protoc-gen-gogo/generator/generator.go

Line 2845 in 3f2ed6d

gogoMoreTags := gogoproto.GetMoreTags(field)

)

in the generateInternalStructFields() method.

protobuf/protoc-gen-gogo/generator/generator.go

Line 2488 in 3f2ed6d

func (g *Generator) generateInternalStructFields(mc *msgCtx, topLevelFields []topLevelField) {

)

But I haven't studied the code in depth; there may be a better way!