FindSQLite3.cmake shadows a module with the same name in upstream CMake with differnt target name

[traversaro]

Since CMake 3.14, CMake provides a find_package(SQLite3 REQUIRED) module that is used if one calls find_package(SQLite3 REQUIRED), that defines the SQLite::SQLite3 imported target. If one calls find_package(ignition-cmake2 REQUIRED) before find_package(SQLite3 REQUIRED), the find_package(SQLite3 REQUIRED) of ign-cmake is used instead, that defines SQLite3::SQLite3 instead.

This can leads to tricky issues, such as when find_package(VTK) is called after find_package(gazebo) (see traversaro/vtk-gazebo-cross-talking#1).

Environment

• OS Version: Ubuntu 22.04
• Source or binary build?
  Binary upstream from Ubuntu 22.04 2.10.0-2

Description

• Expected behavior: After find_package(ignition-cmake2 REQUIRED), find_package(SQLite3 REQUIRED) does not provide SQLite::SQLite3
• Actual behavior: Even if find_package(ignition-cmake2 REQUIRED) is called before, find_package(SQLite3 REQUIRED) should provide SQLite::SQLite3

Steps to reproduce

See traversaro/vtk-gazebo-cross-talking#1 and https://github.com/traversaro/vtk-gazebo-cross-talking/blob/main/.github/workflows/cmake.yml .

Output

-- Found fcl: /usr/include (found suitable version "0.7.0", minimum required is "0.5.0") 
-- Found assimp: /usr/include (found version "5.2.0") 
-- Found DART: /usr/include (Required is at least version "6.6") found components: dart 
-- Found Boost: /usr/lib/x86_64-linux-gnu/cmake/Boost-1.74.0/BoostConfig.cmake (found suitable version "1.74.0", minimum required is "1.40.0") found components: thread system filesystem program_options regex iostreams date_time 
-- Found Protobuf: /usr/lib/x86_64-linux-gnu/libprotobuf.so (found version "3.12.4") 
-- Looking for ignition-math6 -- found version 6.10.0
-- Searching for dependencies of ignition-math6
-- Looking for OGRE...
-- OGRE_PREFIX_WATCH changed.
-- Checking for module 'OGRE'
--   Found OGRE, version 1.9.0
-- Found Ogre Ghadamon (1.9.0)
-- Found OGRE: optimized;/usr/lib/x86_64-linux-gnu/libOgreMain.so;debug;/usr/lib/x86_64-linux-gnu/libOgreMain.so
-- Looking for OGRE_Paging...
-- Found OGRE_Paging: optimized;/usr/lib/x86_64-linux-gnu/libOgrePaging.so;debug;/usr/lib/x86_64-linux-gnu/libOgrePaging.so
-- Looking for OGRE_Terrain...
-- Found OGRE_Terrain: optimized;/usr/lib/x86_64-linux-gnu/libOgreTerrain.so;debug;/usr/lib/x86_64-linux-gnu/libOgreTerrain.so
-- Looking for OGRE_Property...
-- Found OGRE_Property: optimized;/usr/lib/x86_64-linux-gnu/libOgreProperty.so;debug;/usr/lib/x86_64-linux-gnu/libOgreProperty.so
-- Looking for OGRE_RTShaderSystem...
-- Found OGRE_RTShaderSystem: optimized;/usr/lib/x86_64-linux-gnu/libOgreRTShaderSystem.so;debug;/usr/lib/x86_64-linux-gnu/libOgreRTShaderSystem.so
-- Looking for OGRE_Volume...
-- Found OGRE_Volume: optimized;/usr/lib/x86_64-linux-gnu/libOgreVolume.so;debug;/usr/lib/x86_64-linux-gnu/libOgreVolume.so
-- Looking for OGRE_Overlay...
-- Found OGRE_Overlay: optimized;/usr/lib/x86_64-linux-gnu/libOgreOverlay.so;debug;/usr/lib/x86_64-linux-gnu/libOgreOverlay.so
-- Looking for ignition-math6 -- found version 6.10.0
-- Looking for ignition-transport8 -- found version 8.2.1
-- Searching for dependencies of ignition-transport8
-- Found Protobuf: /usr/lib/x86_64-linux-gnu/libprotobuf.so (found suitable version "3.12.4", minimum required is "3") 
-- Config-file not installed for ZeroMQ -- checking for pkg-config
-- Checking for module 'libzmq >= 4'
--   Found libzmq , version 4.3.4
-- Found ZeroMQ: TRUE (Required is at least version "4") 
-- Checking for module 'uuid'
--   Found uuid, version 2.37.2
-- Found UUID: TRUE  
-- Looking for ignition-msgs5 -- found version 5.8.1
-- Searching for dependencies of ignition-msgs5
-- Looking for ignition-math6 -- found version 6.10.0
-- 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")  
-- Checking for module 'jsoncpp'
--   Found jsoncpp, version 1.9.5
-- Found JSONCPP: TRUE  
-- 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
-- Found Threads: TRUE  
-- Found GLEW: /usr/lib/x86_64-linux-gnu/libGLEW.so  
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libOpenGL.so  found components: OpenGL GLX 
-- Found Python3: /usr/bin/python3.10 (found suitable version "3.10.6", minimum required is "3.10") found components: Interpreter Development.Module Development.Embed 
-- Found MPI_C: /usr/lib/x86_64-linux-gnu/libmpi.so (found version "3.1") 
-- Found MPI: TRUE (found version "3.1") found components: C 
-- Found HDF5: /usr/lib/x86_64-linux-gnu/hdf5/serial/libhdf5.so;/usr/lib/x86_64-linux-gnu/libcrypto.so;/usr/lib/x86_64-linux-gnu/libcurl.so;/usr/lib/x86_64-linux-gnu/libpthread.a;/usr/lib/x86_64-linux-gnu/libsz.so;/usr/lib/x86_64-linux-gnu/libz.so;/usr/lib/x86_64-linux-gnu/libdl.a;/usr/lib/x86_64-linux-gnu/libm.so (found version "1.10.7") found components: C HL 
-- Found NetCDF: /usr/include (found version "4.8.1") 
-- Found OGG: /usr/lib/x86_64-linux-gnu/libogg.so  
-- Found THEORA: /usr/lib/x86_64-linux-gnu/libtheora.so  
-- Found JsonCpp: /usr/lib/x86_64-linux-gnu/libjsoncpp.so (found suitable version "1.9.5", minimum required is "0.7.0") 
-- Found LibXml2: /usr/lib/x86_64-linux-gnu/libxml2.so (found version "2.9.13") 
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.11") 
-- Found GL2PS: /usr/lib/x86_64-linux-gnu/libgl2ps.so (found suitable version "1.4.2", minimum required is "1.4.2") 
-- Found PNG: /usr/lib/x86_64-linux-gnu/libpng.so (found version "1.6.37") 
-- Checking for module 'sqlite'
--   No package 'sqlite' found
-- Could not find the VTK package due to a missing dependency: SQLite3
-- Found LibPROJ: /usr/lib/x86_64-linux-gnu/libproj.so (found version "8.2.1") 
-- Found Eigen3: /usr/include/eigen3 (found version "3.4.0") 
-- Found X11: /usr/include   
-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so
-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so - found
-- Looking for gethostbyname
-- Looking for gethostbyname - found
-- Looking for connect
-- Looking for connect - found
-- Looking for remove
-- Looking for remove - found
-- Looking for shmat
-- Looking for shmat - found
-- Looking for IceConnectionNumber in ICE
-- Looking for IceConnectionNumber in ICE - found
-- Found EXPAT: /usr/lib/x86_64-linux-gnu/libexpat.so (found version "2.4.7") 
-- Found double-conversion: /usr/lib/x86_64-linux-gnu/libdouble-conversion.so  
-- 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)

[mjcarroll]

So for gz-cmake3, I think the thing that drives CMake version the most are:

• Ubuntu Focal (CMake 3.16.3-1ubuntu1)
• Ubuntu Jammy (3.22.1-1ubuntu1)

We should probably update the logic to take into account that find_package(SQLite3) is available without any additional logic.

I agree that the cross-talk is definitely unintended and a bug in this case.

[traversaro]

In #313 I provided a minimally invasive change. The tricky aspect is that (as far as I know) once you shadowed a Find<package>.cmake module, there is no way to call via find_package(<package>) the shadowed module. One thing that we could try is to include it via include(<location_of_cmake_modules>/FindSQLite3.cmake) I am not sure how to robustly get <location_of_cmake_modules> or if this does not have strange side effects (CMake scopes rules can be really counterintuitive).

A long term plan could for gz-cmake3 could be to bump the minimum cmake version to 3.14 or 3.16, invert the logic added in traversaro@a61bfc5, i.e. make SQLite::SQLite3 the imported library and SQLite3::SQLite3 the ALIAS library, and mark SQLite3::SQLite3 as deprecated (but unfortunatly the support for deprecating targets is only available since CMake 3.17 : ( https://cmake.org/cmake/help/latest/prop_tgt/DEPRECATION.html ), and eventually remove FindSQLite3.cmake from gz-cmake in gz-cmake4, if that will ever happens.

[azeey]

Since Focal is on 3.16, we can probably deprecate the old functionality.

[scpeters]

A long term plan could for gz-cmake3 could be to bump the minimum cmake version to 3.14 or 3.16, invert the logic added in traversaro@a61bfc5, i.e. make SQLite::SQLite3 the imported library and SQLite3::SQLite3 the ALIAS library, and mark SQLite3::SQLite3 as deprecated (but unfortunatly the support for deprecating targets is only available since CMake 3.17 : ( https://cmake.org/cmake/help/latest/prop_tgt/DEPRECATION.html ), and eventually remove FindSQLite3.cmake from gz-cmake in gz-cmake4, if that will ever happens.

We have bumped the minimum cmake version to 3.22.1 in gz-cmake4 on the main branch, and I've added this issue to #350 tracking things to do with the new cmake features.