I know that it breaks backward compatibility, but the old location clashes on Debian and fixing downstream code should be really easy. So maybe consider for lunar instead?

IMO this could safely merge to Kinetic if it came with a CMakeLists change to maintain compatibility:

# The include/xmlrpcpp path is only for compatibility, to be removed in Lunar.
catkin_package(
  INCLUDE_DIRS include include/xmlrpcpp
  LIBRARIES xmlrpcpp
  CATKIN_DEPENDS cpp_common
)

# The include/xmlrpcpp path is only for compatibility, to be removed in Lunar.
include_directories(include include/xmlrpcpp ${catkin_INCLUDE_DIRS})

Good idea. Why adding the include_directories? Shouldn't the INCLUDE_DIRS be enough?

include_directories affects any binaries being built in the immediate directory or subdirectories of it: https://cmake.org/cmake/help/v3.0/command/include_directories.html

catkin_package (INCLUDE_DIRS) affects what goes into the find module and pkgconfig— it's what will be put on the include path for other packages which build_depend on this one, directly or transitively.

What I'm saying is that it should be enough to add the INCLUDE_DIRS since I fixed all the include_directories in the this package.

Just for clarity, this is @jspricke's counter-proposal:

# The include/xmlrpcpp path is only for compatibility, to be removed in Lunar.
catkin_package(
  INCLUDE_DIRS include include/xmlrpcpp
  LIBRARIES xmlrpcpp
  CATKIN_DEPENDS cpp_common
)

include_directories(include ${catkin_INCLUDE_DIRS})

Oh I see what you mean. Yes, that makes sense.

thanks guys, added :).

I tried building the branch but the xmlrcpcpp package still only exports xmlrpcpp_INCLUDE_DIRS with <prefix>/include and doesn't expose the <prefix>/include/xmlrpccpp path. The catkin_package API assumes that all includes are later installed in an FHS compliant fashion and only <prefix>/include needs to be exported in the install case. I think the additional path needs to be exported using a CMake extra file.

This can easily be tested by not changing the #include directives to ensure the desired backward compatibility works.

@dirk-thomas works fine over here:

$ grep _include_dirs devel/share/xmlrpcpp/cmake/xmlrpcppConfig.cmake
set(_include_dirs "ros_comm/utilities/xmlrpcpp/include;ros_comm/utilities/xmlrpcpp/include/xmlrpcpp"

(I've tested it by recompiling roscpp with the old includes as well)

The devel space works differently. Please check the install space. There it is missing.

@dirk-thomas got it, changed.

Done, @dirk-thomas can you add them here a well: http://answers.ros.org/question/93266/how-to-export-non-standard-include-directories-in-catkin/

LGTM.

I'm not sure I'm doing everything correctly, but while trying to build Kinetic desktop-full from sources on Ubuntu Xenial (amd64) I'm running into a header inclusion problem with XmlRpcValue.h in diagnostic_aggregator:

In file included from /catkin_ws/src/diagnostics/diagnostic_aggregator/src/analyzer_group.cpp:37:0:
/catkin_ws/src/diagnostics/diagnostic_aggregator/include/diagnostic_aggregator/analyzer_group.h:51:25: fatal error: XmlRpcValue.h: No such file or directory
compilation terminated.
make[2]: *** [CMakeFiles/diagnostic_aggregator.dir/src/analyzer_group.cpp.o] Error 1

This seems to be the same issue that is reported in ros/geometry#144 (comment).

It should probably be fixed in ros/diagnostics, but seeing as the change introduced in this PR was supposed to be bw-compatible, I figured I report it here as well.

Adding include/xmlrpcpp to the catkin_package(..) INCLUDE_DIRS in ros_com/xmlrpcpp/CMakeLists.txt:12 does seem to make the build continue.

I'm rather confused as to why this wasn't detected by the CI builds of the pkgs involved.

Perhaps the extras file is not doing what it should be doing?

Which ROS version of desktop-full do you compile? Do you have a minimal example for me to reproduce? Can you check if the xmlrpcpp-extras.cmake is there and used?
Also, can you do a pull request for diagnostics?

ah, and if it's a real bug, please open a new issue, this one is closed and new commends tend to get lost.

re: which version: should have mentioned that, edited my initial comment.

And I should probably also mention I'm building using catkin_tools.

Do you have a minimal example for me to reproduce?

minimal: no? But just following the Kinetic source installation procedure makes this pop up.

Can you check if the xmlrpcpp-extras.cmake is there and used?

It's there. Adding a debug message(..) to it makes it seem as if it's correctly being loaded / evaluated.

Opened #1248.