Public import is not included in generated CommonJS file

System

Version: v3.6.1
Language: Javascript
macOS 10.14

Steps to reproduce

1. Create a src directory with 3 files:

   // id.proto
   syntax = "proto3";
   
   message Id {
     string value = 1;
   }
   

   // task.proto adding a transitive import for `Id`
   syntax = "proto3";
   import public "id.proto";
   
   message Task {
     Id id = 1;
   }
   

   // project.proto importing both `Id` and `Task` from Project
   syntax = "proto3";
   import "task.proto";
   
   message Project {
     Id id = 1;
     repeated Task task = 2;
   }
   

2. Compile to js using

   mkdir build
   protoc --proto_path=src --js_out=import_style=commonjs,binary:build id.proto task.proto project.proto 
   

3. npm install google-protobuf under the root directory.
4. node test.js

   // test.js
   var id_pb = require('./build/id_pb');
   var project_pb = require('./build/project_pb');
   
   var id = new id_pb.Id();
   id.setValue("Everything is fine");
   
   var project = new project_pb.Project()
   project.setId(id);
   
   process.stdout.write(project.getId().getValue());
   process.stdout.write("\n");
   

Expected behaviour

Everything is fine is printed to the console.

Actual behaviour

.../test-proto/build/project_pb.js:173
    jspb.Message.getWrapperField(this, id_pb.Id, 1));
                                       ^

ReferenceError: id_pb is not defined
    at proto.Project.getId (.../test-proto/build/project_pb.js:173:40)
    at Object.<anonymous> (.../test-proto/test.js:10:30)
    at Module._compile (internal/modules/cjs/loader.js:688:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:699:10)
    at Module.load (internal/modules/cjs/loader.js:598:32)
    at tryModuleLoad (internal/modules/cjs/loader.js:537:12)
    at Function.Module._load (internal/modules/cjs/loader.js:529:3)
    at Function.Module.runMain (internal/modules/cjs/loader.js:741:12)
    at startup (internal/bootstrap/node.js:285:19)
    at bootstrapNodeJSCore (internal/bootstrap/node.js:739:3)

id_pb import is missing from project_pb. Alternatively it may be referenced from task_pb, since it’s declared public in task.proto.

The error does not show up if id.proto is explicitly imported in project.proto.

Tái hiện trường hợp bằng lệnh protoc được cung cấp, sau đó kiểm tra build/project_pb.js và các import được tạo cho id_pb và task_pb. Sử dụng test.js để xác minh hành vi; hoàn tất khi import công khai bắc cầu có sẵn cho project_pb.js và script in ra “Everything is fine” mà không yêu cầu import tường minh trong project.proto.