pkg-config detected `xtb` dependency fails to link

[awvwgk]

Building this project against

boost-cpp:      1.74.0
eigen:          3.4.0
scine-core:     4.0.2
scine-utilsos:  5.0.0
xtb:            6.5.1
yaml-cpp:       0.7.0

fails to link with

[8/8] Linking CXX shared library src/Xtb/xtb.module.so
FAILED: src/Xtb/xtb.module.so 
: && $BUILD_PREFIX/bin/x86_64-conda-linux-gnu-c++ -fPIC -fvisibility-inlines-hidden -std=c++17 -fmessage-length=0 -march=nocona -mtune=haswell -ftree-vectorize -fPIC -fstack-protector-strong -fno-plt -O2 -ffunction-sections -pipe -isystem $PREFIX/include -fdebug-prefix-map=$SRC_DIR=/usr/local/src/conda/scine-xtb-1.0.2 -fdebug-prefix-map=$PREFIX=/usr/local/src/conda-prefix -Wall -Wextra -Wpedantic -O2 -g -DNDEBUG  -Wl,-O2 -Wl,--sort-common -Wl,--as-needed -Wl,-z,relro -Wl,-z,now -Wl,--disable-new-dtags -Wl,--gc-sections -Wl,--allow-shlib-undefined -Wl,-rpath,$PREFIX/lib -Wl,-rpath-link,$PREFIX/lib -L$PREFIX/lib  -Wl,--no-as-needed -shared -Wl,-soname,xtb.module.so -o src/Xtb/xtb.module.so src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/GFN0Wrapper.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/GFN1Wrapper.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/GFN2Wrapper.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/GFNFFWrapper.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/XtbCalculatorBase.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/Wrapper/XtbSettings.cpp.o src/Xtb/CMakeFiles/Xtb.dir/Xtb/XtbModule.cpp.o  $PREFIX/lib/libutilsos.so  -llib-xtb-static  -lgfortran  $PREFIX/lib/libboost_filesystem.so.1.74.0  $PREFIX/lib/libboost_system.so.1.74.0  $PREFIX/lib/libblas.so && :
$BUILD_PREFIX/bin/../lib/gcc/x86_64-conda-linux-gnu/10.4.0/../../../../x86_64-conda-linux-gnu/bin/ld: cannot find -llib-xtb-static
collect2: error: ld returned 1 exit status

Due to using the lib-xtb-static target rather than the generated interface library from pkg-config finder.

platform info

     active environment : base
    active env location : /opt/conda
            shell level : 1
       user config file : /home/conda/.condarc
 populated config files : /opt/conda/.condarc
                          /home/conda/.condarc
          conda version : 4.13.0
    conda-build version : 3.22.0
         python version : 3.9.13.final.0
       virtual packages : __linux=5.15.0=0
                          __glibc=2.17=0
                          __unix=0=0
                          __archspec=1=x86_64
       base environment : /opt/conda  (writable)
      conda av data dir : /opt/conda/etc/conda
  conda av metadata url : None
           channel URLs : https://conda.anaconda.org/conda-forge/linux-64
                          https://conda.anaconda.org/conda-forge/noarch
          package cache : /home/conda/feedstock_root/build_artifacts/pkg_cache
                          /opt/conda/pkgs
       envs directories : /opt/conda/envs
                          /home/conda/.conda/envs
               platform : linux-64
             user-agent : conda/4.13.0 requests/2.28.1 CPython/3.9.13 Linux/5.15.0-1014-azure centos/7.9.2009 glibc/2.17
                UID:GID : 1001:1001
             netrc file : None
           offline mode : False

[awvwgk]

I applied this patch as fix

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8618a27..f293f9a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -14,7 +14,10 @@ set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} ${CMAKE_CURRENT_SOURCE_DIR}/dev/cmake
 
 # Find xtb
 find_package(xtb QUIET)
-if(NOT TARGET lib-xtb-static)
+if(TARGET lib-xtb-static)
+  add_library(xtb::xtb INTERFACE IMPORTED)
+  target_link_libraries(xtb::xtb INTERFACE lib-xtb-static)
+else()
   find_package(PkgConfig REQUIRED)
   pkg_check_modules(XTB QUIET xtb)
   if(XTB_FOUND)
diff --git a/src/Xtb/CMakeLists.txt b/src/Xtb/CMakeLists.txt
index 76604eb..d9b4fd2 100644
--- a/src/Xtb/CMakeLists.txt
+++ b/src/Xtb/CMakeLists.txt
@@ -31,7 +31,7 @@ set_target_properties(Xtb PROPERTIES
 target_link_libraries(Xtb
   PRIVATE
     Scine::UtilsOS
-    lib-xtb-static
+    xtb::xtb
     gfortran
   PUBLIC
     Scine::CoreHeaders

[weymutht]

Thanks a lot for reporting this. When doing a default build as explained in the README, we cannot reproduce your linking problems. Furthermore, after applying your patch, CMake fails with the following error:

CMake Error at src/Xtb/CMakeLists.txt:10 (add_library):
  Target "Xtb" links to target "xtb::xtb" but the target was not found.
  Perhaps a find_package() call is missing for an IMPORTED target, or an
  ALIAS target is missing?