Background

I met this problem when trying to set up environment for ROS cartographer. Actually, you can ignore the rosdep update unable to process source bugs. Because I found that my cartographer works well without fixing the bugs.

Solution

You can also try the following commands to fix it by reinstall rosdep.

sudo pip uninstall rosdep

sudo apt-get remove --purge python-rosdep python-pip

sudo apt-get update && sudo apt-get install python-rosdep

Reference

rosdep

rosdep update error