Launch Service not stopping (possibly launch_ros related)

[pbaughman]

Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04 -->
• Installation type:
  • Source
• Version or commit hash:
  • Launch: c644dfa
  • Launch Ros: 84cdecd361a3ea274f77f0c1ec2f2c02097fe372
• DDS implementation:
  • Fast-RTPS

Steps to reproduce issue

I can get this to happen by running ros2 test lifecycle/test/test_lifecycle.py in a loop. Eventually the test will hang after the active tests and before the post-shutdown tests run.

I can determine that launch_testing is stuck in self._launch_service.run()

I can determine the launch service is stuck here

Furthermore, I can print some information about what's in the entity_futures list:

    <Task pending coro=<LaunchService._process_one_event() running at /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py:286> wait_for=<Future
 pending cb=[Task._wakeup()] created at /usr/lib/python3.6/asyncio/base_events.py:295> created at /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py:355>
      [
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py, line 414 in run>,
        <FrameSummary file /usr/lib/python3.6/asyncio/base_events.py, line 471 in run_until_complete>,
        <FrameSummary file /usr/lib/python3.6/asyncio/base_events.py, line 438 in run_forever>,
        <FrameSummary file /usr/lib/python3.6/asyncio/base_events.py, line 1451 in _run_once>,
        <FrameSummary file /usr/lib/python3.6/asyncio/events.py, line 145 in _run>,
        <FrameSummary file /usr/lib/python3.6/asyncio/tasks.py, line 261 in _wakeup>,
        <FrameSummary file /usr/lib/python3.6/asyncio/tasks.py, line 180 in _step>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py, line 355 in run_async>
      ]
    <Future pending cb=[_chain_future.<locals>._call_check_cancel() at /usr/lib/python3.6/asyncio/futures.py:403] created at /usr/lib/python3.6/asyncio/base_events.py:295>
      [
        <FrameSummary file /usr/lib/python3.6/asyncio/tasks.py, line 180 in _step>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py, line 287 in _process_one_event>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/launch_service.py, line 307 in __process_event>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/utilities/visit_all_entities_and_collect_futures_impl.py, line 38 in visit_all_entities_and_collect_futures>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/action.py, line 89 in visit>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch/launch/actions/opaque_function.py, line 75 in execute>,
        <FrameSummary file /home/pete.baughman/gc/apex_ws/build/launch_ros/launch_ros/actions/lifecycle_node.py, line 101 in _on_change_state_event>,
        <FrameSummary file /usr/lib/python3.6/asyncio/base_events.py, line 655 in run_in_executor>,
        <FrameSummary file /usr/lib/python3.6/asyncio/futures.py, line 431 in wrap_future>,
        <FrameSummary file /usr/lib/python3.6/asyncio/base_events.py, line 295 in create_future>
      ]

I'm not so good at asyncio futures, but it looks like I've got one task pending that was created here and another future in the event queue that came from a launch_ros/actions/lifecycle_node that's also waiting for _process_one_event in the launch_service.

Maybe I'm reading the FrameSummary backwards though - like I said I'm not too good at this

Expected behavior

Should not hang!

Actual behavior

Is hanging!

It seems like the lifecycle node's waiting on the LaunchService's _process_one_event is thwarting the 'id_idle' logic that lets us leave this event loop. Perhaps the issue is with launch_ros's Lifecycle node

Additional information

Can someone with a better understanding of what's supposed to be happening here give me a clue for how to debug this further?

[pbaughman]

It looks like this is launch_ros, not launch - closing this in favor of the launch_ros issue