root: fix downstream dd4hep build when +rpath

[sethrj]

When building

dd4hep@1.33+ddalign+ddcad+ddcond+dddetectors+dddigi~ddeve+ddg4+ddrec~debug~doc+edm4hep~geant4units~hepmc3~ipo~lcio~tbb~utilityapps~xercesc
^root@6.38.00~aqua~arrow~cuda~cudnn~cxxmodules~daos~davix~dcache~emacs~examples~fftw~fits~fortran+gdml+geom~geombuilder+gminimal~graphviz+gsl~http~ipo+math+minuit~mlp~opengl~pythia8+python~qt6~r+roofit+root7+rpath~shadow~spectrum~sqlite~ssl~tbb+tiff~tmva~tmva-cpu+tmva-cudnn~tmva-gpu~tmva-pymva~tmva-sofie+tpython+unuran~vc+vdt~veccore~webgui~x+xml~xrootd build_system=cmake build_type=Release cxxstd=20 generator=make patches:=22af347 platform=darwin os=tahoe target=m2 %c,cxx=apple-clang@17.0.0

the final plugin build fails with:

[9/21] Generating libDDCoreGraphics.components
FAILED: [code=1] DDCore/libDDCoreGraphics.components /private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/DDCore/libDDCoreGraphics.components
cd /private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib && DYLD_LIBRARY_PATH=/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib:/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib: /private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/bin/listcomponents_dd4hep -o libDDCoreGraphics.components libDDCoreGraphics.dylib
Error in <UnknownClass::FindDynamicLibrary>: libRIO[.so | .dll | .dylib | .sl | .dl | .a] does not exist in /opt/spack/opt/spack/tahoe/edm4hep/0.99.4/4lpkeqx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib:/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib:/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib::/opt/spack/opt/spack/tahoe/edm4hep/0.99.4/4lpkeqx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib::.:/usr/local/lib:/usr/X11R6/lib:/usr/lib:/lib:/lib/x86_64-linux-gnu:/usr/local/lib64:/usr/lib64:/lib64:
Error in <UnknownClass::FindDynamicLibrary>: libCling[.so | .dll | .dylib | .sl | .dl | .a] does not exist in /opt/spack/opt/spack/tahoe/edm4hep/0.99.4/4lpkeqx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib:/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib:/private/var/folders/n9/mqnx20b929z469f6p3fbq7c40000gn/T/seth/spack-stage/spack-stage-dd4hep-1.33-z7jy2mn65v76gsa5dyg3dlpkevocmuow/spack-build-z7jy2mn/lib::/opt/spack/opt/spack/tahoe/edm4hep/0.99.4/4lpkeqx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib:/opt/spack/opt/spack/tahoe/podio/1.6/sj3ympx/lib::.:/usr/local/lib:/usr/X11R6/lib:/usr/lib:/lib:/lib/x86_64-linux-gnu:/usr/local/lib64:/usr/lib64:/lib64:
Fatal in <TROOT::InitInterpreter>: cannot load symbol dlsym(RTLD_DEFAULT, CreateInterpreter): symbol not found

This appears to be because the ROOT lib path needs to be explicitly defined in ROOT_LIBRARY_PATH, even for rpath builds. See spack/spack#16899, spack/spack#45109 .

Since Spack no longer builds anything older than ROOT 6.28, I've also eliminated the root_library_path property.

[knoepfel]

I just ran into this error this morning. Thanks for the quick fix.

[jmcarcell]

I don't understand well what's going on here. First of all, I have the following builds with ROOT 6.38 with +rpath and DD4hep (master, but nothing related to these issues has changed) that work fine without the changes in this PR, on Alma 9 and Ubuntu 24.04. For example, for Alma 9:

^dd4hep@de2efeb1c5a37e9eb32928cdb23f58f8a31a6f73=develop+ddalign+ddcad+ddcond+dddetectors+dddigi+ddeve+ddg4+ddrec~debug~doc+edm4hep~geant4units+hepmc3~hepmc3-gz+ipo+lcio~tbb+utilityapps+xercesc build_system=cmake build_type=Release commit=de2efeb1c5a37e9eb32928cdb23f58f8a31a6f73 cxxstd=20 generator=ninja arch=linux-almalinux9-x86_64 %c,cxx=gcc@14.2.0
^root@6.38.00~aqua~arrow~cuda~cudnn+cxxmodules~daos+davix~dcache~emacs+examples+fftw~fits~fortran+gdml+geom~geombuilder+gminimal~graphviz+gsl+http+ipo+math+minuit+mlp+opengl~pythia8+python~qt6+r+roofit+root7+rpath~shadow+spectrum+sqlite+ssl+tbb+tiff+tmva+tmva-cpu+tmva-cudnn~tmva-gpu~tmva-pymva~tmva-sofie+tpython+unuran+vc+vdt~veccore+webgui+x+xml+xrootd build_system=cmake build_type=Release cxxstd=20 generator=make patches:=22af347,97ffa00 arch=linux-almalinux9-x86_64 %c,cxx=gcc@14.2.0

Then, if you have enabled +rpath, this PR doesn't change anything (removing LD_LIBRARY_PATH for DD4hep at runtime doesn't change anything at build time) since the change you are proposing is to do what is done now through +rpath always. Or at least I don't see what is different that affects the build.
Other than that, always having the effects of +rpath is good, probably most people build with +rpath anyway.

[sethrj]

I don't understand well what's going on here. First of all, I have the following builds with ROOT 6.38 with +rpath and DD4hep (master, but nothing related to these issues has changed) that work fine without the changes in this PR, on Alma 9 and Ubuntu 24.04.

Hi @jmcarcell, related to AIDASoft/DD4hep#1545 , this might be due to assumptions about X_LIBRARY_PATH being set across the systems. When you build and run on linux do you have those already set?

[sethrj]

@knoepfel Could you reapprove? I've distilled the changeset to a minimal version. Thanks!