Regression introduced with 1.11.8

[piyushk]

@dirk-thomas, @mikaelarguedas

The following snippet was released in action_client.py as part of the latest Kinetic sync, and results in a regression in python based actionlib servers. sub_queue_size defaults to None, which is immediately compared with an integer.

https://github.com/ros/actionlib/blame/indigo-devel/src/actionlib/action_client.py#L531

self.sub_queue_size = rospy.get_param('actionlib_client_sub_queue_size', None)
if self.sub_queue_size < 0:
    self.sub_queue_size = None

Results in:

    client = actionlib.SimpleActionClient('move_base_wrapper', MoveBaseAction)
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/actionlib/simple_action_client.py", line 54, in __init__
    self.action_client = ActionClient(ns, ActionSpec)
  File "/opt/ros/kinetic/lib/python2.7/dist-packages/actionlib/action_client.py", line 532, in __init__
    if self.sub_queue_size < 0:
TypeError: unorderable types: NoneType() < int()

[piyushk]

I just noticed the server suffers from the same issue. The PR has been updated.

[mikaelarguedas]

Thanks @piyushk for reporting it. This arose because python3 is less permissive than python2 in that matter.

[piyushk]

@mikaelarguedas: No problem.

I'm not sure how severe the effect of this issue is though, and whether it would require another Kinetic sync. Maybe @dirk-thomas can comment on it.

[mikaelarguedas]

I don't think it's as severe as what motivated the previous sync. The main reason being that a big part of the ROS stack (starting as low as ros_base packages) doesn't support python3 (dynamic_reconfigure for example), or started to support it very recently. So I wouldn't expect many people to have deployed systems relying on it.

That being said a new release will be made soon with this fix in it and we can see that the next sync will happen in a timely manner to reduce the impact of this bug.

@dirk-thomas How does that sound to you?

[piyushk]

That seems reasonable. We're being forced to use python3 in some ROS scripts due to other dependencies, but I'm not sure how many other people are.

[dirk-thomas]

Sounds good to me.