Trigger service call crashes ros_tcp_endpoint Node

[wyattrees]

Describe the bug
Calling a ROS2 service of type std_srvs/srv/Trigger will crash the default_server_endpoint Node

To Reproduce
Steps to reproduce the behavior:

1. Start a ROS2 Node that has a service of type std_srvs/srv/Trigger alongside the default_server_endpoint Node.
2. Register & call said service from a Unity script.

Console logs / stack traces

servo_1  | [default_server_endpoint-4] Exception in thread Thread-4:
servo_1  | [default_server_endpoint-4] Traceback (most recent call last):
servo_1  | [default_server_endpoint-4]   File "/usr/lib/python3.8/threading.py", line 932, in _bootstrap_inner
servo_1  | [default_server_endpoint-4]     self.run()
servo_1  | [default_server_endpoint-4]   File "/usr/lib/python3.8/threading.py", line 870, in run
servo_1  | [default_server_endpoint-4]     self._target(*self._args, **self._kwargs)
servo_1  | [default_server_endpoint-4]   File "/home/dev_ws/install/ros_tcp_endpoint/lib/python3.8/site-packages/ros_tcp_endpoint/client.py", line 163, in service_call_thread
servo_1  | [default_server_endpoint-4]     response = ros_communicator.send(data)
servo_1  | [default_server_endpoint-4]   File "/home/dev_ws/install/ros_tcp_endpoint/lib/python3.8/site-packages/ros_tcp_endpoint/service.py", line 55, in send
servo_1  | [default_server_endpoint-4]     message = deserialize_message(data, message_type)
servo_1  | [default_server_endpoint-4]   File "/opt/ros/galactic/lib/python3.8/site-packages/rclpy/serialization.py", line 42, in deserialize_message
servo_1  | [default_server_endpoint-4]     return _rclpy.rclpy_deserialize(serialized_message, message_type)
servo_1  | [default_server_endpoint-4] rclpy._rclpy_pybind11.RMWError: failed to deserialize ROS message: rmw_serialize: invalid data size, at /tmp/binarydeb/ros-galactic-rmw-cyclonedds-cpp-0.22.6/src/rmw_node.cpp:1536

Expected behavior
The service call executes successfully.

Screenshots
N/A

Environment (please complete the following information, where applicable):

• Unity Version: Unity 2020.3.18f1
• Unity machine OS + version: Windows 11
• ROS machine OS + version: Ubuntu 20.04, ROS2 Galactic (Also fails on Foxy)
• ROS–Unity communication: Docker
• Branch or version: ROS2v0.7.0

Additional context
Services of other types work as expected. The ROS2 Node I am using in this example is a MoveIt Servo Node. The service I am trying to call is /servo_node/start_servo.

[panagelak]

@wyattrees i solved it by doing a workaround..

at service.py file i imported std_srvs at the top and then i did an if as follows at the send function

    message = None
    if (isinstance(message_type, std_srvs.srv._trigger.Metaclass_Trigger_Request)):
        message = std_srvs.srv.Trigger.Request()
    else:
        message = deserialize_message(data, message_type)