ParameterClient request is not finished although executor is canceled.

Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04
• Installation type:
  • from source
• Version or commit hash:
  • dashing, master
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • rclcpp

Steps to reproduce issue

Parameter Server code

#include <chrono>
#include <iostream>
#include <memory>
#include <vector>

#include <rclcpp/rclcpp.hpp>

int main(int argc, char *argv[]) {
  rclcpp::init(argc, argv);

  rclcpp::executors::SingleThreadedExecutor executor;
  auto node = std::make_shared<rclcpp::Node>("param_test_server_node");
  auto test_param = "test_param";

  rcl_interfaces::msg::ParameterDescriptor descriptor;
  descriptor.read_only = false;
  node->declare_parameter(test_param, rclcpp::ParameterValue(10), descriptor);

  executor.add_node(node);

  node->set_on_parameters_set_callback([&](const std::vector<rclcpp::Parameter> & parameters) {
        rcl_interfaces::msg::SetParametersResult result;
        std::cout << "set_parameter callback is called" << std::endl;
        result.successful = true;
        for (const auto & parameter : parameters) {
          if (parameter.get_name() == test_param)
          {
            std::cout << test_param << " " << parameter.value_to_string() << std::endl;
          }
        }
        std::this_thread::sleep_for(std::chrono::seconds(100));   // To reproduce the issue
        return result;
      });

  executor.spin();

  rclcpp::shutdown();

  return 0;
}

Parameter Client code

#include <chrono>
#include <iostream>
#include <memory>
#include <vector>

#include <rclcpp/rclcpp.hpp>

int main(int argc, char *argv[]) {
  rclcpp::init(argc, argv);

  auto remote_node = "/param_test_server_node";
  auto test_param = "test_param";

  auto exec = std::make_shared<rclcpp::executors::SingleThreadedExecutor>() ;
  auto node = std::make_shared<rclcpp::Node>("param_test_client");

  std::this_thread::sleep_for(std::chrono::seconds(1));

  auto parameters_client =
      std::make_shared<rclcpp::SyncParametersClient>(exec, node, remote_node);

  while (!parameters_client->wait_for_service(std::chrono::seconds(1))) {
    if (!rclcpp::ok()) {
      RCLCPP_ERROR(node->get_logger(), "interrupted, exit!");
      rclcpp::shutdown();
      return 0;
    }
    RCLCPP_INFO(node->get_logger(), "wait for service");
  }

  auto timer_callback = [&]() -> void {
      RCLCPP_INFO(node->get_logger(), "Timer expired");
      exec->cancel();
    };
  auto timer = node->create_wall_timer(std::chrono::seconds(5), timer_callback);

  std::vector<rclcpp::Parameter> set_params;
  set_params.emplace_back(test_param, 50);
  auto results = parameters_client->set_parameters(set_params);
  for (auto &result : results)
    RCLCPP_INFO(node->get_logger(), "result: %d", result.successful);
  RCLCPP_INFO(node->get_logger(), "done");
  timer->cancel();

  rclcpp::shutdown();

  return 0;
}

Expected behavior

Although set_parameters is not finished successfully, if executor is canceled then set_parameters must be finished.

set_parameter callback is called
test_param 50
[INFO] [1583914754.708738050] [param_test_client]: Timer expired
[INFO] [1583914754.709483787] [param_test_client]: done

Actual behavior

set_parameters does not finished although executor is cancled.

set_parameter callback is called
test_param 50
[INFO] [1583914837.349401253] [param_test_client]: Timer expired
[INFO] [1583914842.349311295] [param_test_client]: Timer expired