JS generator missing jspb.generate_from_object option

The comment for jspb.Message.GENERATE_FROM_OBJECT states:

 *     NOTE: By default no protos actually have a fromObject method. You need to
 *     add the jspb.generate_from_object options to the proto definition to
 *     activate the feature.

However, no such option is currently implemented in the open sourced version. I see the code which generates output for this option (GenerateClassFromObject) but it is invoked 0 times.

~/protobuf$ grep -r GenerateClassFromObject .
./src/google/protobuf/compiler/js/js_generator.cc:void Generator::GenerateClassFromObject(const GeneratorOptions& options,
./src/google/protobuf/compiler/js/js_generator.h:  void GenerateClassFromObject(const GeneratorOptions& options,

Can the jspb.generate_from_object option be open sourced?

まず src/google/protobuf/compiler/js/js_generator.cc と js_generator.h を読み、特に GenerateClassFromObject とジェネレーターオプションの処理を確認してください。jspb.generate_from_object が既存の生成パスをどのように有効化すべきかを判断してください。完了条件は、オプションが認識され、生成された JavaScript に期待される fromObject メソッドが生成されることです。