provide urdf_compatibility.h to define SharedPtr types

[rhaschke]

Wily ships with urdfdom 0.3, which doesn't yet declare SharedPtr types. To allow compatibility of Kinetic packages, which typically already rely on those types, we ship a urdf_compatibility.h header.

@wjwwood suggested to apply this PR here, in the very first ROS package using urdfdom, and not in downstream packages like MoveIt: moveit/moveit#18 (comment).

Downstream packages simply need to #include <urdf/urdf_compatibility.h>.

[wjwwood]

Thanks @rhaschke, I can use this in rviz too.

[wjwwood]

Looks like CI is choking on this line. Are you sure it is necessary? I guess you want to do something like what gencpp does for the generated message headers:

https://github.com/ros/gencpp/blob/indigo-devel/cmake/gencpp-extras.cmake.em#L49-L57

[rhaschke]

This line is necessary to export the include path in devel-space context. However, I indeed missed to create that folder beforehand. I guess, it is created with configure_file(), but I moved the whole block past catkin_package() because of the use of CATKIN_PACKAGE_INCLUDE_DESTINATION.

[davetcoleman]

@wjwwood what kind of delay will we see in releasing this package into Kinetic? I'd like to get moveit released quickly and moving this PR here from moveit/moveit#317 seems like a potential big delay

[wjwwood]

I'll make a release as soon as this patch is merged to expedite the process, though I would like to test this patch out with rviz before releasing to ensure it is sufficient.

[rhaschke]

For MoveIt, it doesn't suffice to declare SharedPtr types in the compatibility header. At some places, MoveIt already includes urdf_world/types.h or urdf_model/types.h which were introduced with urdfdom 0.4 only.
So we need some more #ifdefs in the source.

[rhaschke]

With the latest commit, MoveIt seems to compile on Wily: I essentially removed all includes of urdf_world/types.h, which I proposed to remove with ros/urdfdom_headers#33.
Instead urdf_model/types.h should correctly declare ModelInterfaceSharedPtr in future.
For now, as a workaround, urdf/model.h includes the compatibility header, which in turn (re)declares all shared pointer types.
I didn't yet tested rviz.

[rhaschke]

@wjwwood I'm just building rviz on Wily with this patch. Some changes are required, which I will file as a PR as soon as build is successful.

[wjwwood]

Testing this now.

[wjwwood]

Cool it works for me in a Wily docker building rviz with this patch and ros-visualization/rviz#1064.

Thanks again @rhaschke! I'll merge this now and start a release.

[wjwwood]

I did a release with this pr just now: ros/rosdistro#13092

[v4hn]

@wjwwood could we get this compatibility header released in indigo too?
This would probably simplify things and ease cross-distro compilation of moveit's kinetic branch on ROS indigo.

[wjwwood]

If someone does the pr to the right branch I'll look at it next time I spend time on robot_model.