FindROOT.cmake needs to be updated

[clark2668]

The one that exists now is out of date, and doesn't work when compiling with ROOT6. L339 (https://github.com/ara-software/AraRoot/blob/master/cmake/Modules/FindROOT.cmake#L339) seems to incorrectly reset the LD_LIBRARY_PATH variable, and this results in AraRoot being compiled with a different version of gcc relative to one of it's core dependencies, root, which causes the build to break. The soulution seems to be to go from:

COMMAND LD_LIBRARY_PATH=${ROOT_LIBRARY_DIR} ROOTSYS=${ROOTSYS} ${ROOT_CINT_EXECUTABLE}

to

COMMAND ROOTSYS=${ROOTSYS} ${ROOT_CINT_EXECUTABLE}

[uzairlatif90]

Hey Brian! So I did suffer from this issue when I was trying to install AraRoot in the KU cluster. The LD_LIBRARY_PATH would get reset every time I ran the build script and would latch onto the wrong compiler. I think I eventually just commented out the problematic line which is the one that you have pointed out here.

In AnitaBuildTools the different components generally seem to follow the prescription given on the ROOT website here: https://root.cern.ch/how/integrate-root-my-project-cmake

@cozzyd pointed out that it can just pick up the FindROOT.cmake file from ROOT itself. I was looking at AnitaBuildTools and in there only the libRootFftwWrapper has its own pre-made module folder which contains the FindROOT.cmake file. The rest of the anitaBuildTools component seem to be picking it up from there. Like in the CMakeLists.txt for libRootFftwWrapper you have:

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_SOURCE_DIR}/cmake/modules/")

and in the CMakeLists.txt for UCorrelator you have:

set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${UTIL_SHARE_DIR}/cmake/modules/")

would it be a safe bet if we just pick it up from the libRootFftwWrapper for AraRoot too? I remember I tried and it lead me into wall errors printed out on my screen (I will have to look into that again) but I can work on that and see if I can tame it down to match with what AraRoot wants. If I have to change it too much (or even one line I guess) then we can include the new changed version with AraRoot. Then we would not have to change the default file that comes with libRootFftwWrapper.

Let me know what you guys think about this.

[cozzyd]

at the very least we should fix the LD_LIBRARY_PATH define that breaks things. But I think getting the upstream FindROOT.cmake is the right thing except that there might be other things in the CMakeLists.txt that depend on the custom way of running the dictionary generation?

[clark2668]

I mean, it seems like someone would just need to try the newer FindROOT.cmake and see what happens, right?

[uzairlatif90]

So for that you would just need to pick up the newer FindROOT.cmake from the ROOT installation and then include that with the AraRoot files? I can give it a try but it will just take me a while to get to it. Just have a couple of other things going on right now.