fixed reference counting bug (#44)

src/orchpylib.cc

@@ -564,10 +564,13 @@ PyObject* deserialize_call(PyObject* self, PyObject* args) {
     worker->decrement_reference_count(objrefs);
   }
   int resultsize = call->result_size();
+  std::vector<ObjRef> result_objrefs;
   PyObject* resultlist = PyList_New(resultsize);
   for (int i = 0; i < resultsize; ++i) {
     PyList_SetItem(resultlist, i, make_pyobjref(worker_capsule, call->result(i)));
+    result_objrefs.push_back(call->result(i));
   }
+  worker->decrement_reference_count(result_objrefs); // The corresponding increment is done in RemoteCall in the scheduler.
   PyObject* t = PyTuple_New(3); // We set the items of the tuple using PyTuple_SetItem, because that transfers ownership to the tuple.
   PyTuple_SetItem(t, 0, string);
   PyTuple_SetItem(t, 1, arglist);

src/scheduler.cc

@@ -16,11 +16,14 @@ Status SchedulerService::RemoteCall(ServerContext* context, const RemoteCallRequ
   size_t num_return_vals = fntable_[task->name()].num_return_vals();
   fntable_lock_.unlock();
 
+  std::vector<ObjRef> result_objrefs;
   for (size_t i = 0; i < num_return_vals; ++i) {
     ObjRef result = register_new_object();
     reply->add_result(result);
     task->add_result(result);
+    result_objrefs.push_back(result);
   }
+  increment_ref_count(result_objrefs); // The corresponding decrement will happen in deserialize_call in orchpylib.
 
   task_queue_lock_.lock();
   task_queue_.emplace_back(std::move(task));