Fill unrecognized options

[leviska]

I'm writing custom service_generator for http backend, and have this code sample

fn method_config(method: &Method) -> Option<TokenStream> {
  if !method.options.uninterpreted_option.is_empty() {
    panic!("{:#?}", method.options.uninterpreted_option);
  }
  // <...>
}

And I have this proto

//<...>
rpc GetSources(GetSourcesRequest) returns (GetSourcesResponse) {
  option (google.api.http) = {
    get : "/sources"
  };
}

And compilation doesn't fail, meaning the uninterpreted_options are empty
In the docs there is a comment about something related:

A message representing a option the parser does not recognize. This only appears in options protos created by the compiler::Parser class. DescriptorPool resolves these when building Descriptor objects. Therefore, options protos in descriptor objects (e.g. returned by Descriptor::options(), or produced by Descriptor::CopyTo()) will never have UninterpretedOptions in them.

But it seems outdated, because I can't find compiler::Parser at all.

I've tested deprecated option, and it works fine, so I really don't understand why can't prost fill this option too.

I really want to parse this option, but as of now can't figure out how to do it. Is there a way, can I help contribute to prost with something to make this happen?

[LucioFranco]

The type is generated from the google protobuf types here https://github.com/protocolbuffers/protobuf/blob/main/src/google/protobuf/descriptor.proto#L741 and probably refers to the C++ implementation. We just copy the comments. Prost just uses protoc so maybe there is a flag you can set to get that. Prost doesn't do much special here than other implementations as for getting the data from the file descriptor set.

[leviska]

oof, that's sad, but I'll look into it, thanks :)

[leviska]

As I understand, this options are stored in extensions: https://stackoverflow.com/questions/41165197/how-to-get-the-method-options-from-protobuf-descriptor

I've checked the raw output of the protoc, and there are some strings with my http paths, but in the resulting FileDescriptorProto there are none. Any thoughts about how can I integrate extensions in Rust?

[leviska]

Ah, I see it here #674