Subscription segfaults on take

[hidmic]

Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• Installation type:
  • From source
• Version or commit hash:
  • Current master
• DDS implementation:
  • ADLINK CycloneDDS, RTI Connext
• Client library (if applicable):
  • rclpy

Steps to reproduce issue

1. Start up a listener, e.g.

ros2 run demo_nodes_py listener

2. Start up a talker, e.g.

ros2 run demo_nodes_py talker

3. Once they are communicating, Ctrl-C the talker.

Expected behavior

Talker exits and listener stops receiving messages.

Actual behavior

Talker exits and listener segfaults.

Additional information

Limited backtrace:

#0  0x00000000005a8c1d in PyTuple_Pack ()                                                  
#1  0x00007ffff6fd185c in rclpy_take ()                                                    
   from /home/michel/Workspaces/focal_ros2_ws/install/rclpy/lib/python3.8/site-packages/rclpy/_rclpy.cpython-38-x86_64-linux-gnu.so                                                    
#2  0x00000000005f268a in PyCFunction_Call ()                                              
#3  0x00000000005f31fe in _PyObject_MakeTpCall ()
#4  0x000000000056c50e in _PyEval_EvalFrameDefault ()
#5  0x0000000000507a8e in ?? ()

The issue does not occur when using eProsima Fast-RTPS.

[hidmic]

Well, it's a regression introduced by #542. I'll make a patch.

[wjwwood]

Thanks for fixing it @hidmic, @iluetkeb FYI.