Failure to build ros2_ouster driver with perception_pcl source in workspace

[sgvandijk]

I am trying to build both pcl_conversions and ros2_ouster from source. Mainly because I work with Humble, and the following fix has not made it into the Humble release yet: https://github.com/ros-perception/perception_pcl/pull/384 meaning that installing ros-humble-pcl-conversions pulls in 1.2GB of stuff. For the same reason I also do the same for ros2_ouster.

However, the build of ros2_ouster fails with the following error:

CMake Error at /usr/lib/x86_64-linux-gnu/cmake/jsoncpp/jsoncpp-namespaced-targets.cmake:5 (add_library):
  add_library cannot create imported target "JsonCpp::JsonCpp" because
  another target with the same name already exists.
Call Stack (most recent call first):
  /usr/lib/x86_64-linux-gnu/cmake/jsoncpp/jsoncppConfig.cmake:41 (include)
  CMakeLists.txt:24 (find_package)

I am submitting this as an issue here rather than at ros2_ouster, because reverting https://github.com/ros-perception/perception_pcl/pull/392 results in a successful build. I.e., changing:

ament_export_dependencies(${dependencies} PCL)

back to

ament_export_dependencies(${dependencies})

I am not 100% exactly what happens, but I assume that PCL exports the JsonCpp::JsonCpp target, which conflicts with the target being created by find_package(jsonccp REQUIRED) in ros2_ouster's CMakeLists.txt. I think the way ros2_ouster finds and links to jsoncpp is reasonable/correct, so I feel that the issue then lies with pcl_conversions or PCL itself. But happy to file this somewhere else if that seems more appropriate.

To reproduce:

With a ROS2 Humble installation:

mkdir testws
cd testws
mkdir src
git clone -b ros2 https://github.com/ros-perception/perception_pcl.git src/perception_pcl
git clone -b humble https://github.com/ros-drivers/ros2_ouster_drivers.git src/ros2_ouster_drivers
rosdep install --from-paths src/ -y -r --ignore-src
colcon build

[SteveMacenski]

This appears to be an error with jsoncpp. That export of library dependences with PCL is correct and shouldn't be reverted as far as I can tell.

[CharlesAntoineParent]

@sgvandijk Did you solve your problem ? I encountered the same problem and I am still trying to fix it !