[Humble] Buffer cannot transform b/c of TypeException

[RobinHeitz]

Bug report

Required Info:

• Operating System:
  Ubuntu 22.04.02
• Installation type:
  Binaries inside Docker Container
• Client library (if applicable):
  rclpy

Steps to reproduce issue

1. Launch static transform publisher
   ros2 run tf2_ros static_transform_publisher --x 1.0 --y 2.0 --frame-id world --child-frame-id child_frame

2. Launch the following node:

import rclpy
from geometry_msgs.msg import PoseStamped
from rclpy.node import Node
from tf2_ros import TransformException
from tf2_ros.buffer import Buffer


class TestPoseTransformation(Node):
    def __init__(self):
        super().__init__("test_pose_transform_node")
        self.tf_buffer = Buffer()

        self.pose_stamped = PoseStamped()
        self.pose_stamped.header.frame_id = "child_frame"
        self.pose_stamped.header.stamp = self.get_clock().now().to_msg()
        self.pose_stamped.pose.position.x = 0.1
        self.pose_stamped.pose.position.z = 0.4
        self.pose_stamped.pose.orientation.w = 1.0

        self.get_logger().info("Initialized Node")
        self.timer = self.create_timer(1.0, self.transform_pose_stamped)


    def transform_pose_stamped(self):
        try:
            t = self.tf_buffer.transform(self.pose_stamped, "world")
            print(t)

        except TransformException as e:
            self.get_logger().error(f"Could not transform: {e}")



def main(args=None):
    rclpy.init(args=args)
    node = TestPoseTransformation()
    rclpy.spin(node)
    node.destroy_node()
    rclpy.shutdown()

if __name__ == "__main__":
    main()

Expected behavior

I would expect that the pose_stamped is transformed from child_frame to world.

Actual behavior

TypeException: Type <class 'geometry_msgs.msg._pose_stamped.PoseStamped'> is not loaded or suported.

Additional information

Complete Stacktrace

[INFO] [1720622250.237926650] [test_pose_transform_node]: Initialized Node
Traceback (most recent call last):
  File "/home/ros/ros_ws/install/neura_lara8_description/lib/neura_lara8_description/test_pose_transformation", line 33, in <module>
    sys.exit(load_entry_point('neura-lara8-description', 'console_scripts', 'test_pose_transformation')())
  File "/home/ros/ros_ws/build/neura_lara8_description/neura_lara8_description/test_pose_transformation.py", line 37, in main
    rclpy.spin(node)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/__init__.py", line 222, in spin
    executor.spin_once()
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/executors.py", line 739, in spin_once
    self._spin_once_impl(timeout_sec)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/executors.py", line 736, in _spin_once_impl
    raise handler.exception()
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/task.py", line 239, in __call__
    self._handler.send(None)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/executors.py", line 437, in handler
    await call_coroutine(entity, arg)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/executors.py", line 351, in _execute_timer
    await await_or_execute(tmr.callback)
  File "/opt/ros/humble/local/lib/python3.10/dist-packages/rclpy/executors.py", line 107, in await_or_execute
    return callback(*args)
  File "/home/ros/ros_ws/build/neura_lara8_description/neura_lara8_description/test_pose_transformation.py", line 26, in transform_pose_stamped
    t = self.tf_buffer.transform(self.pose_stamped, "world")
  File "/opt/ros/humble/lib/python3.10/site-packages/tf2_ros/buffer_interface.py", line 95, in transform
    do_transform = self.registration.get(type(object_stamped))
  File "/opt/ros/humble/lib/python3.10/site-packages/tf2_ros/buffer_interface.py", line 278, in get
    raise TypeException('Type %s is not loaded or supported' % str(key))
tf2_ros.buffer_interface.TypeException: Type <class 'geometry_msgs.msg._pose_stamped.PoseStamped'> is not loaded or supported
[ros2run]: Process exited with failure 1

[RobinHeitz]

Currently having this error (again), was amused to find my own issue I had previously 😆

[clalancette]

So, there is a simple, if non-obvious, fix for this. And that is to add in import tf2_geometry_msgs at the top of the Python file. That will go ahead and load in the registration for the PoseStamped message, along with other things.

That said, I don't love how this shakes out, because it is really non-obvious that this is what is required. I'd have to think about a better way to restructure this whole thing to make it work better, or at least be more obvious what needs to be done.