fix reference modification in generate_dynamic

[jpetereit]

Reference modification in generate_dynamic can fail in certain cases.

Consider a custom message my_geometry_msgs/Vector3WithCovariance consisting of

geometry_msgs/Vector3 vector
float64[9]            covariance

When modifying the references in generate_dynamic, there is an erroneous match for my_geometry_msgs.msg.Vector3WithCovariance, which results in a wrong symbol after replacement (my__geometry_msgs__Vector3WithCovariance instead of _my_geometry_msgs__Vector3WithCovariance).

This happens because the currently used string replacement strategy is too simplistic. It does not check if it is actually replacing a full symbol.

[dirk-thomas]

I tried to reproduce the issue you describe but was not successful. Can you please post a complete example with step-by-step instructions?

Are you trying this with the latest sources of genpy since very recently #37 has been addressed?

[jpetereit]

I've checked out the latest version and the error does still occur.

I hope the following steps can help you to reproduce the bug:

1. Check out my test workspace.

2. catkin_make

3. source devel/setup.bash

4. This step is optional. You may just use the bag file dump.bag that is contained in my test case. It was created by

   $ rosbag record -O dump.bag /mytopic
   

   and then publishing some iosb_sensor_msgs/GpsWithVelocity messages with rqt_publisher.

   Optional: $ rosbag info dump.bag

   path:        dump.bag
   version:     2.0
   duration:    3.0s
   start:       Oct 05 2015 13:09:11.58 (1444043351.58)
   end:         Oct 05 2015 13:09:14.58 (1444043354.58)
   size:        13.5 KB
   messages:    4
   compression: none [1/1 chunks]
   types:       iosb_sensor_msgs/GpsWithVelocity [bfe1b7f396cf11c6c14531104407ff0c]
   topics:      /mytopic   4 msgs    : iosb_sensor_msgs/GpsWithVelocity
   

5. Finally, run

   $ rostopic echo -b dump.bag /mytopic
   

   which results in the following error:

   Traceback (most recent call last):
   File "/opt/ros/jade/bin/rostopic", line 35, in <module>
    rostopic.rostopicmain()
   File "/opt/ros/jade/lib/python2.7/dist-packages/rostopic/__init__.py", line 1765, in rostopicmain
    _rostopic_cmd_echo(argv)
   File "/opt/ros/jade/lib/python2.7/dist-packages/rostopic/__init__.py", line 1136, in _rostopic_cmd_echo
    _rostopic_echo(topic, callback_echo, bag_file=options.bag)
   File "/opt/ros/jade/lib/python2.7/dist-packages/rostopic/__init__.py", line 767, in _rostopic_echo
    _rostopic_echo_bag(callback_echo, bag_file)
   File "/opt/ros/jade/lib/python2.7/dist-packages/rostopic/__init__.py", line 745, in _rostopic_echo_bag
    for t, msg, timestamp in b.read_messages():
   File "/opt/ros/jade/lib/python2.7/dist-packages/rosbag/bag.py", line 2306, in read_messages
    yield self.seek_and_read_message_data_record((entry.chunk_pos, entry.offset), raw)
   File "/opt/ros/jade/lib/python2.7/dist-packages/rosbag/bag.py", line 2455, in seek_and_read_message_data_record
    msg = msg_type()
   File "/tmp/genpy_uyHqoq/tmpWAffIp.py", line 157, in __init__
    self.velocity = iosb__geometry_msgs__Vector3WithCovariance()
   NameError: global name 'iosb__geometry_msgs__Vector3WithCovariance' is not defined
   

Please let me know if you need any further help to reproduce the issue.

[dirk-thomas]

Thank you for the detailed example as well as the patch. I have squashed both commits and only changed the import order (to follow PEP8): 06cc06b