Closure templates and proto file descriptors

[Anton Kovalyov]

Hi,

We're trying to have Closure Templates compiler understand our protos so that we could specify them as types. I.e. the following example (the gen.model.Post is defined in a protobuf file):

{template .index}
  {@param post: gen.model.Post}
  // ...
{/template}

We've updated to the latest versions of closure-templates which recently introduced a new flag --protoFileDescriptors. I wasn't deeply familiar with the Google/Closure ecosystem when I embarked on this project so I initially I thought that proto file descriptors are the .proto files themselves. Now it seems that it's a some kind of a binary format generated by the protoc compiler. I'm able to generate one with this command:

protoc --descriptor_set_out=test.desc --include_imports --proto_path=../src/main/protobuf,lib/proto/model lib/proto/model/**.proto

However, when I try to pass it to closure-templates compiler it fails with a mysterious (to me) error:

INTERNAL SOY ERROR.

Please open an issue at https://github.com/google/closure-templates/issues with this stack trace and repro steps

java.lang.IllegalArgumentException: ExtensionRegistry.add() must be provided a default instance when adding an embedded message extension.
 at com.google.protobuf.ExtensionRegistry.add(ExtensionRegistry.java:264)
 at com.google.template.soy.types.proto.SoyProtoTypeProvider$RegisterExtensionsDescriptorTreeWalker.visitExtensionDescriptor(SoyProtoTypeProvider.java:256)
 at com.google.template.soy.types.proto.DescriptorTreeWalker.walkGenericDescriptor(DescriptorTreeWalker.java:178)
 at com.google.template.soy.types.proto.DescriptorTreeWalker.walkGenericDescriptors(DescriptorTreeWalker.java:168)
 at com.google.template.soy.types.proto.SoyProtoTypeProvider$RegisterExtensionsDescriptorTreeWalker.visitFileDescriptor(SoyProtoTypeProvider.java:246)
 at com.google.template.soy.types.proto.DescriptorTreeWalker.walkFileDescriptor(DescriptorTreeWalker.java:151)
 at com.google.template.soy.types.proto.DescriptorTreeWalker.walkFileDescriptorSet(DescriptorTreeWalker.java:146)
 at com.google.template.soy.types.proto.DescriptorTreeWalker.walkFileDescriptorSetFromByteSource(DescriptorTreeWalker.java:119)
 at com.google.template.soy.types.proto.SoyProtoTypeProvider$Builder.walkAll(SoyProtoTypeProvider.java:107)
 at com.google.template.soy.types.proto.SoyProtoTypeProvider$Builder.build(SoyProtoTypeProvider.java:125)
 at com.google.template.soy.AbstractSoyCompiler.doMain(AbstractSoyCompiler.java:177)
 at com.google.template.soy.AbstractSoyCompiler.access$000(AbstractSoyCompiler.java:49)
 at com.google.template.soy.AbstractSoyCompiler$2.main(AbstractSoyCompiler.java:149)
 at com.google.template.soy.MainClassUtils.runInternal(MainClassUtils.java:255)
 at com.google.template.soy.AbstractSoyCompiler.run(AbstractSoyCompiler.java:146)
 at com.google.template.soy.AbstractSoyCompiler.runMain(AbstractSoyCompiler.java:138)
 at com.google.template.soy.SoyToJsSrcCompiler.main(SoyToJsSrcCompiler.java:192)

My question, however, is more generic: is there a document somewhere describing what proto file descriptors are and how to use them with closure templates?

Thanks,

Anton

[Hochhaus, Andy]

Hi Anton!

Great to see more usage of soy proto support.

On Mon, Jan 30, 2017 at 1:01 PM, 'Anton Kovalyov' via Closure
Templates Discuss <closure-temp...@googlegroups.com> wrote:
> My question, however, is more generic: is there a document somewhere
> describing what proto file descriptors are and how to use them with closure
> templates?

I only know of minimal docs at
https://developers.google.com/protocol-buffers/docs/techniques.



In case you have not already seen it, the bazel build tool has a
project called rules_closure. I added support to it for using soy
templates with protobufs:

https://github.com/bazelbuild/rules_closure/
https://github.com/bazelbuild/rules_closure/commit/1cae2870f435a78feb45d24f0626e118eda2d217

The goal of rules_closure is to make working with the entire closure
ecosystem trivial so it might be worth checkout out.

Best,
Andy

[Hochhaus, Andy]

On Mon, Jan 30, 2017 at 7:18 PM, Hochhaus, Andy <ahoc...@samegoal.com> wrote:
> I only know of minimal docs at
> https://developers.google.com/protocol-buffers/docs/techniques.

I intended to link to:

https://developers.google.com/protocol-buffers/docs/techniques#self-description