Issue with ament_cmake_gen_version_h install path in ros2 build farm

[saikishor]

Hello!

In ros2_control, we have recently added the version header generation using ament_cmake_gen_version_h package, however, from them, the build farm is failing showing the following error. Can someone help us in finding the issue in the changes (https://github.com/ros-controls/ros2_control/pull/1449/files)?. With the changes local builds and CI builds works without any issue.

Reference job : https://build.ros2.org/job/Rbin_uN64__joint_limits__ubuntu_noble_amd64__binary/61/

10:35:21 -- Installing: /tmp/binarydeb/ros-rolling-joint-limits-4.10.0/debian/ros-rolling-joint-limits/opt/ros/rolling/share/joint_limits/package.xml
10:35:21 CMake Error at cmake_install.cmake:145 (file):
10:35:21   file INSTALL cannot find
10:35:21   "/tmp/binarydeb/ros-rolling-joint-limits-4.10.0/.obj-x86_64-linux-gnu/ament_generate_version_header/joint_limits/joint_limits/version.h":
10:35:21   No such file or directory.

Thank you :)

[clalancette]

In short, this is a bug in ament_generate_version_header, specifically having to do with INTERFACE libraries.

The longer version is that it takes a combination of factors for this to happen, all of which only happen with this package on the buildfarm:

1. You need to have BUILD_TESTING=OFF.
2. You need to be using ament_generate_version_header.
3. The target you are generating for needs to be an INTERFACE only package.

On the ROS 2 buildfarm, all of those are true joint_limits. In that case, what happens in
https://github.com/ros-controls/ros2_control/blob/edfb971c55f54f26272fbe38ee134859d7938d41/joint_limits/CMakeLists.txt is that there is no "build" time, and so the target that should be made up-to-date in

ament_cmake/ament_cmake_gen_version_h/cmake/ament_generate_version_header.cmake

Lines 150 to 151 in 79cc237

	add_custom_target("ament_generate_version_header__${target}"
	DEPENDS "${GENERATED_HEADER_FILE}")

(which ultimately generates the version.h file), is just never run.

The fix is actually a one-liner; see #526 for it. What I'm going to suggest in the short-term, though, is that you actually just remove ament_generate_version_header from this package, and this package alone.

[saikishor]

Hello @clalancette!

Thanks a lot for responding. Sure, for now we will remove it from the joint_limits package.

Thank you!