CMake macros should not use environment variables about fairroot HOT 4 CLOSED

just to track all discussions, link to #652

from fairroot.

I see some points here:

1. Variables to influence CMake to for example find dependencies. This is an ongoing task and 19.0 has removed a lot of this and moved to cmake's default search methods. This sometimes has some drawbacks, but it generally is on a good way.

2. Variables that currently need to be set when using FairRoot (after configure, build, install). For the time being there is some config.sh that should have all sthe setup code to get an environment for using FairRoot. We are fully aware, that we want to get rid of this and bake good defaults into the library. The progress on this isn't as good as we would like it to be.

We could see this ticket as a general reminder, that we still have work left to do.

I personally prefer actionable items.
Are there any particular environment variables of concern? Ones that interfere with other things?

from fairroot.

• For discovery of dependencies, we should follow CMake standard behavior as close as possible and not add package manager specific requirements (at least not hard-code them as it was done in the past). The user can then steer CMake's search procedure in great detail:
  • CMAKE_FIND_USE_PACKAGE_ROOT_PATH
  • CMAKE_FIND_USE_CMAKE_PATH
  • CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH
  • CMAKE_FIND_USE_PACKAGE_REGISTRY
  • CMAKE_FIND_USE_CMAKE_SYSTEM_PATH
• $SIMPATH we should keep for historical reasons, but really make it behave as if one would prepend to CMAKE_PREFIX_PATH (which CMake also reads from an environment variable $CMAKE_PREFIX_PATH) - that way it is covered by the switches from above and can naturally be disabled.
• All other uses (that are not part of standard CMake behaviour) that read an environment variable during FairRoot configure/build/install time, we should remove.

If the above conditions are met, I consider this issue as resolved.

from fairroot.

Reopen the issue, if still needed.

from fairroot.