On Mon, Jul 12, 2010 at 7:40 PM, Ken Conley <kwc@willowgarage.com> wrote:
> More information here:
>
> http://www.ros.org/news/2010/07/ros-c-turtle-alpha-5-released.html
>
>  -- your friendly neighborhood ROS C Turtle team

We have been upgrading many of our students from boxturtle to cturtle.
The binary installs seem to work fine. But several students stumbled
over problems of binary incompatibility for external packages built
with the two releases.

After installing the cturtle packages, they update $ROS_PACKAGE_PATH
and try to run their code. It generally segfaults, and they don't know
what to do (these are smart, but relatively inexperienced
undergraduates).

Even running rosmake again does not work. Apparently, the build
subtree is full of incompatible files. So, they need to at least use
the rosmake --pre-clean option. I've been recommending that they check
out a whole new tree and build that.

So, this is not a big deal, but I was surprised how much confusion it
created. It should probably be documented somehow in the release
notes.

If it were possible for rosmake and rosrun to detect packages built
with the old ABI and issue a clear warning, that would help a lot.
Even better if rosmake could automatically do the right thing (e.g.
"make clean && make").

I consider this more of a documentation issue than a defect, but
probably many more users will stumble over it soon.
-- 
 joq