Building ROOT under a conda environment

[oxon]

According to this thread, the reason may be the incompatibility of the compilers used for the ROOT build (system Clang 10.0.1) and Python build (Anaconda uses Clang 4.0.1 for Python build).

Problem with Installing PyRoot

You should not specify PYTHON_INCDIR and PYTHON_LIBDIR by hand. That’s why your configuration is not working. You are using python from one place (/usr), and the libraries from another (/usr/local). You should only use -DPYTHON_EXECUTABLE=/full/path/to/python, then only use ROOT with that particular python. Python libraries are not compatible for different versions. In addition, you need to use the same compiler (or a compatible one) to the one that was used to compile the python you want to use…

(cta_root_test) $ otool -L $ROOTSYS/lib/libPyROOT.so             
/usr/local/root-6.16.00/obj_conda/lib/libPyROOT.so:
	@rpath/libPyROOT.so (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libTree.so (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libpython3.6m.dylib (compatibility version 3.6.0, current version 3.6.0)
	@rpath/libtbb.dylib (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libRIO.so (compatibility version 0.0.0, current version 0.0.0)
	@rpath/libCore.so (compatibility version 0.0.0, current version 0.0.0)
	/usr/lib/libc++.1.dylib (compatibility version 1.0.0, current version 400.9.4)
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1252.250.1)

(cta_root_test)$ otool -L `which python3`          
/Users/oxon/anaconda3/envs/cta_root_test/bin/python3:
	/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)

The both uses the same /usr/lib/libSystem.B.dylib, but the versions printed are 1252.250.1 for libPyROOT.so and 1197.1.1 for python3.

Is this the reason of the seg fault? Any workaround?