Launch error in tf2 tutorial: AttributeError: 'ellipsis' object has no attribute 'describe_sub_entities'
Hi,
I've just been going through the tf2 tutorial for ros2 foxy and I'm having a lot of trouble with the launch files (and I'm just copy/pasting the files as they come in the tutorial), they throw this error:
/dev_ws# ros2 launch learning_tf2_py turtle_tf2_demo.launch.py Task exception was never retrieved future: <task finished="" name="Task-2" coro="<LaunchService._process_one_event()" done,="" defined="" at="" opt="" ros="" foxy="" lib="" python3.8="" site-packages="" launch="" launch_service.py:226=""> exception=AttributeError("'ellipsis' object has no attribute 'describe_sub_entities'")> Traceback (most recent call last): File "/opt/ros/foxy/lib/python3.8/site-packages/launch/launch_service.py", line 228, in _process_one_event await self.__process_event(next_event) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/launch_service.py", line 248, in __process_event visit_all_entities_and_collect_futures(entity, self.__context)) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py", line 45, in visit_all_entities_and_collect_futures futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py", line 45, in visit_all_entities_and_collect_futures futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py", line 38, in visit_all_entities_and_collect_futures sub_entities = entity.visit(context) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/action.py", line 108, in visit return self.execute(context) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/actions/include_launch_description.py", line 145, in execute declared_launch_arguments = launch_description.get_launch_arguments() File "/opt/ros/foxy/lib/python3.8/site-packages/launch/launch_description.py", line 126, in get_launch_arguments process_entities(self.entities, _conditional_inclusion=conditional_inclusion) File "/opt/ros/foxy/lib/python3.8/site-packages/launch/launch_description.py", line 120, in process_entities entity.describe_sub_entities(), _conditional_inclusion=False) AttributeError: 'ellipsis' object has no attribute 'describe_sub_entities'
I've verified that the error is not related to my installation as same thing happens in a docker container. I'm kind of in a hurry, do you have any clue what's going on? the launch file is:
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
def generate_launch_description():
return LaunchDescription([
...,
DeclareLaunchArgument(
'target_frame', default_value='turtle1',
description='Target frame name.'
),
Node(
package='learning_tf2_py',
executable='turtle_tf2_broadcaster',
name='broadcaster2',
parameters=[
{'turtlename': 'turtle2'}
]
),
Node(
package='learning_tf2_py',
executable='turtle_tf2_listener',
name='listener',
parameters=[
{'target_frame': LaunchConfiguration('target_frame')}
]
),
])