Telcon: 2021 11 24

Attendees

• Peter Scheibel
• Massimiliano Culpo
• Erik Palmer
• Mark Krentel
• Todd Gamblin
• Greg Becker

Agenda

• Extension of the spec syntax to allow specifying edge attributes and DAG structure: https://github.com/spack/seps/pull/5
  • Draft proposal
  • This is needed for both separate concretization of build dependencies and compiler as dependencies

Agenda items for next week

• Multiple providers of same virtual package
  • Case 1: we want blas from X and lapack from Y
  • Case 2: we actually want several instances of the same virtual (e.g. to run different instances of MPI for the same root)
• Possibly revisit: https://github.com/spack/spack/discussions/24966
  • Concerning improvements to spack develop
• Harmen (not sure if I can join): there are packages like libblastrampoline / libmpitrampoline which provide a blas / lapack / mpi interface to link to, and forwards calls to an actual blas / lapack / mpi provider lib. E.g. julia uses it to link to a blas interface for its binary deps, allowing the user to switch blas provider at runtime, avoiding abi issues. The problem is Spack only allows one provider per dag, but these packages both provides the virtual and depends on the virtual. How do we deal with this "composition" type of pattern? I was thinking: maybe we can relax unique provider per dag to unique provider per subgraph connected through link type deps? Then libblastrampoline can provide blas, and depend on blas as a run-type dependency.
  • Mark Krentel: https://github.com/spack/spack/issues/27157
• Peter: Can we get rid of csh support
  • I always run bash first thing when I start a shell on Mac OS
  • Does anywhere require CSH support and have no option for bash support?