On Fri, Jun 29, 2012 at 4:22 AM, Lorenz Mösenlechner <moesenle@in.tum.de> wrote:
> Hi,
>
> the recent addition of multiple author lines to the stack.xml file in
> the ROS stack is incompatible with the specification used in previous
> versions of the rospkg library distributed with ROS Fuerte. This is
> not a big issue on freshly installed ROS systems since there is a Debian
> package for rospkg now. However, when installing rosdep using
> easy_install or pip, it also pulls in rospkg, whether or not it has
> been installed already using the Debian package.
>
> Based on a few questions at answers.ros.org, it seems like this
> change caused a lot of trouble. It looks like people followed the
> install instructions from the wiki page and installed rosdep. At some
> point, they updated ROS to the new version with the changes to
> stack.xml. Without doing an additional easy_install or pip update or
> removing rospkg from /usr/local/lib by hand, this results in a broken
> ROS installation where even roscore doesn't work anymore.

Well said, Lorentz.

This was a very serious breakage. Updating the Debian packages on my
primary Fuerte/Oneiric ROS development system caused roscore to stop
working. That should *never* happen with a released distribution.

> While this update does fix some other problems related to the ROS
> stack.xml file,
> I really wonder if it was a good idea to make such a fundamental
> change in a released and officially stable ROS distro. Maybe it's time
> to branch off for Groovy?

I am not sure even that would fix the root cause of this problem. We
have essential build tools being distributed separately from the
distributions.

We need a wiki page explaining exactly which Python packages to
install for running, building and releasing packages for each
supported distribution. We also need a way to determine whether those
packages are up to date.

> Also, why does rosdep actually still depend on rospkg although it is
> now installed through apt? I don't feel like it's good to have two
> possibly conflicting versions of rospkg installed on my system.

My development system is still broken, despite several attempts to
straighten things out using easy_install and pip. The fact that
easy_install provides no clean way to uninstall something makes things
more difficult. It is far too confusing, trying to figure out which
scripts are installed via Debian packages, which are installed via pip
or easy_install, and what are the dependencies between them.
-- 
 joq