Cross-talking between find_package(gazebo) and find_package(VTK) on Ubuntu 22.04

[traversaro]

This issue (and repo) is meant to provide a simple reproducible example of the problems created by calling find_package(gazebo) and find_package(VTK) in the same project on Ubuntu 22.04 .

find_package(gazebo) called before find_package(VTK)

Job: https://github.com/traversaro/vtk-gazebo-cross-talking/actions/runs/3151955287/jobs/5126569789

Error:

-- Found LZ4: /usr/lib/x86_64-linux-gnu/liblz4.so (found version "1.9.3") 
-- Found LZMA: /usr/lib/x86_64-linux-gnu/liblzma.so (found version "5.2.5") 
-- Found JPEG: /usr/lib/x86_64-linux-gnu/libjpeg.so (found version "80") 
-- Found TIFF: /usr/lib/x86_64-linux-gnu/libtiff.so (found version "4.3.0")  
-- Found Freetype: /usr/lib/x86_64-linux-gnu/libfreetype.so (found version "2.11.1") 
-- Found utf8cpp: /usr/include/utf8cpp  
-- VTK_VERSION: 9.1.0
-- Configuring done
CMake Error at /usr/lib/x86_64-linux-gnu/cmake/vtk-9.1/VTK-targets.cmake:1268 (set_target_properties):
-- Generating done
  The link interface of target "VTK::sqlite" contains:

    SQLite::SQLite3

  but the target was not found.  Possible reasons include:

    * There is a typo in the target name.
    * A find_package call is missing for an IMPORTED target.
    * An ALIAS target is missing.

Call Stack (most recent call first):
  /usr/lib/x86_64-linux-gnu/cmake/vtk-9.1/vtk-config.cmake:138 (include)
  CMakeLists.txt:10 (find_package)


CMake Generate step failed.  Build files cannot be regenerated correctly.

This problem is the one described in gazebosim/gz-cmake#312 that will be fixed in gazebosim/gz-cmake#313 .

find_package(gazebo) called after find_package(VTK)

Job: https://github.com/traversaro/vtk-gazebo-cross-talking/actions/runs/3151955287/jobs/5126569952

Error:

-- Checking for module 'tinyxml2'
--   Found tinyxml2, version 9.0.0
-- Looking for ignition-msgs5 -- found version 5.8.1
-- Looking for ignition-common3 -- found version 3.14.0
-- Searching for dependencies of ignition-common3
-- Looking for dlfcn.h - found
-- Looking for libdl - found
-- Found DL: TRUE  
-- Found tinyobjloader: /usr/lib/x86_64-linux-gnu/cmake/tinyobjloader/tinyobjloader-config.cmake (found version "2.0.0") 
-- Searching for <ignition-common3> component [graphics]
-- Looking for ignition-common3-graphics -- found version 3.14.0
-- Searching for dependencies of ignition-common3-graphics
-- Looking for ignition-math6 -- found version 6.10.0
-- Looking for ignition-fuel_tools4 -- found version 4.4.0
-- Searching for dependencies of ignition-fuel_tools4
-- Found CURL: /usr/lib/x86_64-linux-gnu/libcurl.so (found version "7.81.0")  
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)
  /usr/share/cmake/ignition-cmake2/cmake2/FindJSONCPP.cmake:34 (find_package)
  /usr/lib/x86_64-linux-gnu/cmake/ignition-fuel_tools4/ignition-fuel_tools4-config.cmake:94 (find_package)
  /usr/lib/x86_64-linux-gnu/cmake/gazebo/gazebo-config.cmake:251 (find_package)
  CMakeLists.txt:17 (find_package)


-- Checking for module 'yaml-0.1'
--   Found yaml-0.1, version 0.2.2
-- Found YAML: TRUE  
-- Checking for module 'libzip'
--   Found libzip, version 1.7.3
-- Found ZIP: TRUE  
-- Looking for ignition-common3 -- found version 3.14.0
-- Looking for ignition-math6 -- found version 6.10.0
-- Looking for ignition-msgs5 -- found version 5.8.1
-- Configuring incomplete, errors occurred!

The problem here is the one described in open-source-parsers/jsoncpp#1356, that will be eventually fixed by open-source-parsers/jsoncpp#1435 .

[traversaro]

Workaround

A workaround for this issues is to call find_package(gazebo) before find_package(VTK), and then after find_package(gazebo) is called restore the CMAKE_MODULE_PATH present before find_package(gazebo) was called, something like:

set(_CMAKE_MODULE_PATH_BACKUP "${CMAKE_MODULE_PATH}")
find_package(gazebo REQUIRED)
set(CMAKE_MODULE_PATH "${_CMAKE_MODULE_PATH_BACKUP}")
find_package(VTK REQUIRED)