Import Error: Class Loader undefined symbol

[togaen]

I am getting undefined symbol errors trying to get info on a ROS 1 bag file. I am on ROS 2 Foxy and I installed everything using apt. The bag file has no custom messages, only std_msgs/Header and std_msgs/Float32 messages.

The README states that ROS 1 must be sourced first in order to avoid problems with the class loader. The relevant section of my bashrc looks like this:

source /opt/ros/noetic/setup.bash                                               
source /opt/ros/foxy/setup.bash

Even so, I get the below error:

$ ros2 bag info -s rosbag_v2 bag.bag
Traceback (most recent call last):
  File "/opt/ros/foxy/bin/ros2", line 11, in <module>
    load_entry_point('ros2cli==0.9.7', 'console_scripts', 'ros2')()
  File "/opt/ros/foxy/lib/python3.8/site-packages/ros2cli/cli.py", line 67, in main
    rc = extension.main(parser=parser, args=args)
  File "/opt/ros/foxy/lib/python3.8/site-packages/ros2bag/command/bag.py", line 38, in main
    return extension.main(args=args)
  File "/opt/ros/foxy/lib/python3.8/site-packages/ros2bag/verb/info.py", line 40, in main
    from rosbag2_transport import rosbag2_transport_py
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosbag2_transport/__init__.py", line 38, in <module>
    rosbag2_transport_py = _import('._rosbag2_transport_py')
  File "/opt/ros/foxy/lib/python3.8/site-packages/rosbag2_transport/__init__.py", line 27, in _import
    return importlib.import_module(name, package='rosbag2_transport')
  File "/usr/lib/python3.8/importlib/__init__.py", line 127, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
ImportError: /opt/ros/foxy/lib/librosbag2_storage.so: undefined symbol: _ZNK12class_loader11ClassLoader15isLibraryLoadedEv
The C extension '/opt/ros/foxy/lib/python3.8/site-packages/rosbag2_transport/_rosbag2_transport_py.cpython-38-x86_64-linux-gnu.so' failed to be imported while being present on the system. Please refer to 'https://index.ros.org/doc/ros2/Troubleshooting/#import-failing-even-with-library-present-on-the-system' for possible solutions

Also, the link given in the error message doesn't seem to point to an existing section anymore: https://github.com/ros2/rosbag2/issues/458

[Karsten1987]

Could you please verify that you source first noetic followed by foxy? Make sure you have a fresh terminal and no modifications in your bashrc. I can reproduce your error when sourcing foxy before noetic. However, when noetic is sourced first, it works just fine for me.

[Karsten1987]

I am going to close this issue as I think this issue is solved by sourcing noetic before foxy. @togaen Please don't hesitate to re-open this ticket in case your problem still persists.

[togaen]

@Karsten1987 Sorry I missed your reply, somehow I had notifications turned off. I am still seeing this error even in a fresh terminal with a bashrc containing the following:

source /opt/ros/noetic/setup.bash                                               
source /opt/ros/foxy/setup.bash

If it's relevant, I also get this message every time I open a terminal:

ROS_DISTRO was set to 'foxy' before. Please make sure that the environment does not mix paths from different distributions.
ROS_DISTRO was set to 'noetic' before. Please make sure that the environment does not mix paths from different distributions.

Would have any ideas what else might be going on?

[togaen]

In case anyone else has this issue, it turned out for me to just be that the ROS paths had be set session-wide instead of just per shell session. Setting the right source order then logging out and back in fixed it for me.

[dringlourious]

any update now?

[dra2494]

Hello all,

having the same error, even if noetic is sourced first in the fresh terminal. Any help would be much appreciated

[doraemon96]

Hi! I'm having the same issue, working from a fresh docker (FROM osrf/ros:foxy-desktop)

If anyone was able to find a solution and can provide a Dockerfile with steps I'd be more than grateful!

[Madhav2133]

Hi all, I am facing same issue. I use ros2-galactic

ImportError: /opt/ros/galactic/lib/librosbag2_storage.so: undefined symbol: _ZNK12class_loader11ClassLoader15isLibraryLoadedEv

Please let me know if there's any resolve for this issue. Thanks

[OlgaMatykina]

If you use docker and into.sh, you should check that foxy isn't sourced in into.sh