Asyncio traceback when closing

[ivanpauno]

Bug report

Required Info:

• Operating System:
  • Ubuntu 18.04
• Installation type:
  • from source
• Version or commit hash:
  • 67c2006
• DDS implementation:
  • Fast-RTPS
• Client library (if applicable):
  • N/A

Steps to reproduce issue

Example launch file with the issue:

import signal

from launch import LaunchDescription
from launch import LaunchService
from launch.actions import EmitEvent
from launch.actions import ExecuteProcess
from launch.actions import TimerAction
from launch.events.process import matches_action
from launch.events.process import SignalProcess
from launch.substitutions import FindExecutable


def run_ls():
    exec_action = ExecuteProcess(
        cmd=[FindExecutable(name='python3'), '-c', '"while(1): pass"'],
        shell=True)
    kill_timer = TimerAction(
            period=5.0,
            actions=[
                EmitEvent(
                    event=SignalProcess(
                        signal_number=signal.SIGTERM,
                        process_matcher=matches_action(exec_action)))
                ])
    ld = LaunchDescription([
        exec_action,
        kill_timer,
    ])
    ls = LaunchService(debug=True)
    ls.include_launch_description(ld)
    assert 0 == ls.run()


if __name__ == '__main__':
    run_ls()
    run_ls()

I ran it doing python3 SCRIPT_NAME

Expected behavior

End after the five seconds timeout without an exception.

Actual behavior

After ending, this error happens:

Exception ignored in: <bound method BaseSubprocessTransport.__del__ of <_UnixSubprocessTransport closed pid=3649 returncode=-15 stdin=<_UnixWritePipeTransport closing fd=7 open> stdout=<_UnixReadPipeTrans
port fd=8 open> stderr=<_UnixReadPipeTransport fd=10 open>>>
Traceback (most recent call last):
  File "/usr/lib/python3.6/asyncio/base_subprocess.py", line 132, in __del__
    self.close()
  File "/usr/lib/python3.6/asyncio/base_subprocess.py", line 106, in close
    proto.pipe.close()
  File "/usr/lib/python3.6/asyncio/unix_events.py", line 624, in close
    self.write_eof()
  File "/usr/lib/python3.6/asyncio/unix_events.py", line 610, in write_eof
    self._loop.call_soon(self._call_connection_lost, None)
  File "/usr/lib/python3.6/asyncio/base_events.py", line 580, in call_soon
    self._check_closed()
  File "/usr/lib/python3.6/asyncio/base_events.py", line 366, in _check_closed
    raise RuntimeError('Event loop is closed')
RuntimeError: Event loop is closed

Additional information

This is strange, because all is working fine and an exception is being raised when closing from asyncio lib. I couldn't find a simpler repro. I had a similar problem when working with #178. I only could repro this error when using shell=True option in ExecuteProcess.