Failed to concretize spec: unsatisfiable constraints – concretizer nondeterminism in Spack
Goal: obtain a Spack environment that concretizes to the same concrete spec every time, regardless of when it is built or which Spack version is used, so that builds are repeatable across teams and CI pipelines. Concern: the default concretizer does not guarantee deterministic output; the resulting concrete spec can vary with the ordering of packages in spac