Configuration fails on Linux host with librealsense2 installed

[taketwo]

Configuring a fresh master clone with cmake .. fails on a Linux host that has librealsense2 installed:

-- RealSense SDK 2 found (include: , lib: realsense2::realsense2, version: 2.10.0)
CMake Error at cmake/pcl_targets.cmake:823 (include_directories):
  include_directories given empty-string as include directory.
Call Stack (most recent call first):
  CMakeLists.txt:326 (PCL_ADD_GRABBER_DEPENDENCY)

[SergioRAgostinho]

I'm not able to replicate this. I've tried different realsense2 version and different cmake versions. My realsense2 installation is local and I always specify the path to the config file. Do you have a global installation?

[taketwo]

Probably; I'll need to double-check next time I have access to that host.

[kunaltyagi]

I used the current HEAD, and installed librealsense-v2.30.0-1 followed by successful compilation.

-- RealSense SDK support: not building because RSSDK not found
-- RealSense SDK 2 found (include: /home/kt/catkin_ws/devel/include, lib: realsense2::realsense2, version: 2.30.0)

But since I used ninja, it called cmake configure a second time and the following warnings showed up:

CMake Warning (dev) at /home/kt/catkin_ws/devel/lib/cmake/realsense2/realsense2Targets.cmake:28 (if):
Policy CMP0054 is not set: Only interpret if() arguments as variables or
keywords when unquoted.  Run "cmake --help-policy CMP0054" for policy
details.  Use the cmake_policy command to set the policy and suppress this
warning.

Quoted variables like "" will no longer be dereferenced when the policy is
set to NEW.  Since the policy is not set the OLD behavior will be used.
Call Stack (most recent call first):
/home/kt/catkin_ws/devel/lib/cmake/realsense2/realsense2Config.cmake:35 (include)
cmake/Modules/FindRSSDK2.cmake:12 (find_package)
cmake/pcl_targets.cmake:817 (find_package)
CMakeLists.txt:326 (PCL_ADD_GRABBER_DEPENDENCY)
This warning is for project developers.  Use -Wno-dev to suppress it.

CMake Warning (dev) at /home/kt/catkin_ws/devel/lib/cmake/realsense2/realsense2Targets.cmake:36 (if):
Policy CMP0054 is not set: Only interpret if() arguments as variables or
keywords when unquoted.  Run "cmake --help-policy CMP0054" for policy
details.  Use the cmake_policy command to set the policy and suppress this
warning.

Quoted variables like "" will no longer be dereferenced when the policy is
set to NEW.  Since the policy is not set the OLD behavior will be used.
Call Stack (most recent call first):
/home/kt/catkin_ws/devel/lib/cmake/realsense2/realsense2Config.cmake:35 (include)
cmake/Modules/FindRSSDK2.cmake:12 (find_package)
cmake/pcl_targets.cmake:817 (find_package)
CMakeLists.txt:326 (PCL_ADD_GRABBER_DEPENDENCY)
This warning is for project developers.  Use -Wno-dev to suppress it.

-- RealSense SDK 2 found (include: /home/kt/catkin_ws/devel/include, lib: realsense2::realsense2, version: 2.30.0)

The warnings look similar to your errors so it might be something relevant. I used CMake 3.15.5 (for reference)

[SergioRAgostinho]

@kunaltyagi your particular warnings are coming from realsense2 not explicitly setting certain policies. It looks like something completely different.

[kunaltyagi]

Oh. That means global and local installs both work fine. Except the machine config @taketwo used.

[taketwo]

Apparently this is a problem with that particular version of librealsense2. The config file that it generates looks like this:

####### Expanded from @PACKAGE_INIT@ by configure_package_config_file() #######
####### Any changes to this file will be overwritten by the next CMake run ####
####### The input file was realsense2Config.cmake.in                            ########

get_filename_component(PACKAGE_PREFIX_DIR "${CMAKE_CURRENT_LIST_DIR}/../../../" ABSOLUTE)

macro(set_and_check _var _file)
  set(${_var} "${_file}")
  if(NOT EXISTS "${_file}")
    message(FATAL_ERROR "File or directory ${_file} referenced by variable ${_var} does not exist !")
  endif()
endmacro()

macro(check_required_components _NAME)
  foreach(comp ${${_NAME}_FIND_COMPONENTS})
    if(NOT ${_NAME}_${comp}_FOUND)
      if(${_NAME}_FIND_REQUIRED_${comp})
        set(${_NAME}_FOUND FALSE)
      endif()
    endif()
  endforeach()
endmacro()

####################################################################################

set(realsense_VERSION_MAJOR "2")
set(realsense_VERSION_MINOR "10")
set(realsense_VERSION_PATCH "0")

set_and_check(realsense_INCLUDE_DIR "${PACKAGE_PREFIX_DIR}/include")

include("${CMAKE_CURRENT_LIST_DIR}/realsense2Targets.cmake")
set(realsense2_LIBRARY realsense2::realsense2)

Note that it sets realsense_INCLUDE_DIR and not realsense2_INCLUDE_DIR. Thus our finder script is not able to pick it up.

This problem is not present in newer versions, so I don't think we need to deal with it. Cloning this; sorry for the noise.