Steps to reproduce the issue

$ spack spec slurm | grep glib
    ^[email protected]

but this version of glib is marked as deprecated.

I can nudge clingo into taking a newer version of glib:

$ spack spec slurm ^[email protected]: | grep glib
    ^[email protected]

and it concretizes fine to the latest glib.

The problem is that [email protected] depends on meson whereas [email protected] does not, and this ultimately pulls in a virtual dependency on uuid only for the former.

Apparently clingo prefers fewer virtual dependencies over newer versions, so it ends up preferring [email protected] even though it is deprecated.

When setting variant('uuid', default=False, description='Build uuid module') by default in Python, spack spec slurm concretizes to using [email protected] indeed.

So I think there's 2 issues:

• Clingo should try to prefer new versions over fewer virtual deps
• Clingo should avoid concretizing to deprecated packages when there is an alternative

Information on your system

• Spack: 0.16.0-1812-8d2944bf77
• Python: 3.8.7
• Platform: linux-ubuntu20.04-zen2
• Concretizer: clingo

Additional information

• I have run spack debug report and reported the version of Spack/Python/Platform
• I have searched the issues of this repo and believe this is not a duplicate