Telcon: 2021 09 22

Attendees

• Todd Gamblin
• Greg Becker
• Peter Scheibel
• Harmen Stoppels
• Timothy Brown
• Ben Fulton
• John Porter
• Justin Phillips
• Kayla Butler
• Luke Roskop
• Mark Krentel
• Massimiliano Culpo
• Tammy Dahlgren

Agenda

• Harmen Stoppels

  • Only load root specs in an environment: https://github.com/spack/spack/pull/25755
  • Remove setup_dependent_run_environment in favor of setup_run_environment: https://github.com/spack/spack/pull/26031
    • setup_dependent_run_environment: used by the Python package (py-* packages call Python.setup_dependent_run_environment, and it traverses the DAG to modify PYTHONPATH)
    • Now that we have PythonPackage, can we remove Python.setup_dependent_run_environment?
    • If you recursively load a DAG with multiple py-* packages, does this mean that Python.setup_dependent_run_environment will traverse the DAG once for each py-* dependency?
  • Should spack load x be ± equivalent to spack env activate my_env where my_env has x as a root spec and no view? https://github.com/spack/spack/pull/25732 spack load needs some love
  • Todd: we should discuss the intended semantics of:
    • What happens when a module is loaded
    • What happens with spack load
    • These should ideally be the same

• (TBC from last week) Discussion: Packages which require multiple build systems: how to handle them?

  • Discussions on this:
    • (Proposal based on using a new directive) https://github.com/spack/seps/blob/8dafadb4cae08275d168af964b3d168b4248977f/seps/sep-0002.md
    • (Notes on trying an approach based on a when class decorator) https://github.com/spack/seps/issues/4
  • Two approaches were covered: Greg thought there were issues with both; we will cover that next week.

• Discussion: Packages with multiple conflicting libraries - how to support them?

  • For now, any such package installed by Spack advertises just one from the set (this ensures that everything is consistent where needed)
  • https://github.com/spack/seps/pull/2
  • Brian: opencv will try to install its own openblas (which may conflict with what Spack chooses)
    • Mvapich2 installs its own hwloc
    • (Peter) I think this is a separate but still interesting problem.

• (For next week) What about packages that install some other package with them

  • E.g. Mvapich2 installs hwloc with it
  • Would it be good to allow a Spack package to describe these additional packages that "come along" with it

• Discussion: long environment activations - are you having an issue with this?

  • Some large envs might have this problem, e.g.: https://github.com/spack/spack/issues/25555