fixing bug, unaccounted for reference counting (#48)

src/orchpylib.cc

@@ -637,9 +637,12 @@ PyObject* remote_call(PyObject* self, PyObject* args) {
   request.release_call(); // TODO: Make sure that call is not moved, otherwise capsule pointer needs to be updated
   int size = reply.result_size();
   PyObject* list = PyList_New(size);
+  std::vector<ObjRef> result_objrefs;
   for (int i = 0; i < size; ++i) {
     PyList_SetItem(list, i, make_pyobjref(worker_capsule, reply.result(i)));
+    result_objrefs.push_back(reply.result(i));
   }
+  worker->decrement_reference_count(result_objrefs); // The corresponding increment is done in RemoteCall in the scheduler.
   return list;
 }
 

src/scheduler.cc

@@ -25,7 +25,8 @@ Status SchedulerService::RemoteCall(ServerContext* context, const RemoteCallRequ
   }
   {
     std::lock_guard<std::mutex> reference_counts_lock(reference_counts_lock_); // we grab this lock because increment_ref_count assumes it has been acquired
-    increment_ref_count(result_objrefs); // The corresponding decrement will happen in deserialize_call in orchpylib.
+    increment_ref_count(result_objrefs); // We increment once so the objrefs don't go out of scope before we reply to the worker that called RemoteCall. The corresponding decrement will happen in remote_call in orchpylib.
+    increment_ref_count(result_objrefs); // We increment once so the objrefs don't go out of scope before the task is scheduled on the worker. The corresponding decrement will happen in deserialize_call in orchpylib.
   }
 
   task_queue_lock_.lock();