enforce correct message type is passed to various API

[dirk-thomas]

Closes #314.

The PR contains two commits:

• Adding tests passing an invalid type to the various APIs PR and expecting a TypeError to be raised. CI with these tests failing: ( intentionally failing tests)
• Update the implementation to check the passes type and raise TypeError in case it doesn't match the expected type:

[dirk-thomas]

Full build to ensure no code relies on using the API in that way:

[sloretz]

What does this traceback look like? I would have expected the exception to be swallowed here:

rclpy/rclpy/rclpy/task.py

Lines 212 to 213 in afc4cd4

	except Exception as e:
	self.set_exception(e)

[dirk-thomas]

Output of the test without the with self.assertRaises(TypeError)::

rclpy/__init__.py:204: in spin_until_future_complete
    executor.spin_until_future_complete(future, timeout_sec)
rclpy/executors.py:271: in spin_until_future_complete
    self.spin_once(timeout_sec=timeout_sec)
rclpy/executors.py:628: in spin_once
    raise handler.exception()
rclpy/task.py:206: in __call__
    self._handler.send(None)
rclpy/executors.py:382: in handler
    await call_coroutine(entity, arg)
rclpy/executors.py:337: in _execute_service
    srv.send_response(response, header)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

self = <rclpy.service.Service object at 0x7f549dd3bc88>
response = 'different response type'
header = <capsule object "rmw_request_id_t" at 0x7f549dd3c4e0>

    def send_response(self, response: SrvTypeResponse, header) -> None:
        """
        Send a service response.
    
        :param response: The service response.
        :param header: Capsule pointing to the service header from the original request.
        :raises: TypeError if the type of the passed response isn't an instance
          of the Response type of the provided service when the service was
          constructed.
        """
        if not isinstance(response, self.srv_type.Response):
>           raise TypeError()
E           TypeError

rclpy/service.py:79: TypeError

[sloretz]

Ohh I didn't know about

rclpy/rclpy/rclpy/executors.py

Lines 627 to 628 in afc4cd4

	if handler.exception() is not None:
	raise handler.exception()

That's a nice improvement