Add support for the ruby_package file option added in protobuf v3.6.0

[lwc]

Admittedly this is a little hacky, but once descriptor.proto in golang/protobuf catches up to the protocolbuffers/protobuf version the hack can come out.

Fixes #19

[marioizquierdo]

Is this the way to check if the option is recognized or not?

[marioizquierdo]

not yet in golang/protobuf

this code should not concern with the version of golang/protobuf or protocolbuffers/protobuf that is being used, because the version may change at anytime (and the comment would be worthless). Maybe a better way to describe this struct is that the Package property will contain the ruby_package option if the protobuf compiler supports it. I would just comment the field like this:

// RubyPackageParser struct to use with proto.Unmarshal and the file descriptor. 
type RubyPackageParser struct {
	// RubyPackageOption is the ruby_package option in the proto file.
	// It is empty if there is no option, or if not supported by the proto package
	// This option was added in protocolbuffers/protobuf v3.6.0+
	OptionRubyPackage string `protobuf:"bytes,45,opt,name=ruby_package,json=rubyPackage,proto2" json:"ruby_package,omitempty"`
}

[marioizquierdo]

The generator code has this imports:

import (
	// ...
	"github.com/golang/protobuf/proto"
	"github.com/golang/protobuf/protoc-gen-go/descriptor"
	plugin "github.com/golang/protobuf/protoc-gen-go/plugin"
)

I think this means that it always generates code with golang/protobuf, instead of with protocolbuffers/protobuf, is that right?

However, when generating code with the protoc command, if the option ruby_package is added, the service.pb.rb file properly contains the modules specified in the option. I think this means that golang/protobuf already supports the ruby_package option?

I installed protoc through brew, that uses the source https://github.com/google/protobuf/ and shows version libprotoc 3.6.0.

[marioizquierdo]

@lwc any chance you can take a look at this?

[marioizquierdo]

Closing for inactivity