ROOT 6.30.01 unable to find module.modulemap when packaged via fpm

[ktf]

Check duplicate issues.

• Checked for duplicates

Description

We have our own packaging of root via fpm which relocates our builds which happen in some folder in /tmp to and rpm which installs in /opt/o2.

This was working fine in v6.28.00 however when switching to v6-30-01 we have a bunch of errors along the lines of:

Module Net not found.
Error in <TCling::LoadPCM>: ROOT PCM /opt/o2/lib/libNet_rdict.pcm file does not exist
Module MultiProc not found.
Module Imt not found.
Module MathCore not found.
Error in <TCling::LoadPCM>: ROOT PCM /opt/o2/lib/libMathCore_rdict.pcm file does not exist
Error in <TClass::LoadClassInfo>: no interpreter information for class TSignalHandler is available even though it has a TClass initialization routine.
Error in <TClass::LoadClassInfo>: no interpreter information for class TFileHandler is available even though it has a TClass initialization routine.

when starting root on the command line.

By doing a strace, we figured out that this derives from root not being able to find module.modulemap which is present in /opt/o2/include, yet it is not considered. We are able to workaround the issue by simply copying module.modulemap in the current directory, which is apparently in the search path, however that is clearly not a viable solution in a deployed environment.

What mechanism is used by default to lookup module.modulemap? We would be fine if we could work it around via some environment variable or systemrc tweak.

Reproducer

Build root in one folder and relocate it to a different one.

ROOT version

v6-30-01. v6-28-01 works fine.

Installation method

alibuild, fpm

Operating system

el8

Additional context

This is preventing ALICE DAQ to use the latest ROOT.

[vgvassilev]

Do you have the pcm files in $ROOTSYS/lib? What does it expand to? /opt/o2/lib/?

[ktf]

We do not have ROOTSYS set explicitly, however even if I set it by hand, it produces the same result.

In /opt/o2/lib we do not have /opt/o2/lib/libNet_rdict.pcm, however we do have /opt/o2/lib/Net.pcm, not sure if that's the issue.

[Barthelemy]

And to add on top of that, I would still be interested to understand where the modulemap files are searched and if there is another environment variable we could set to force the search in /opt/o2/include.

[ktf]

Any idea of what might be going on here? To a first loop, we just need a some hint on how to force the lookup, and then we can add a workaround in our packaging instructions.

[vgvassilev]

I do not have time to look at this now. Maybe in a week?

[ktf]

That would be great. Anything we can try on our own?