Currently, the concretizer emits facts for all versions known to Spack, including deprecated versions, and has a specific optimization objective to minimize their use.
This commit simplifies how deprecated versions are handled by considering possible versions for a spec only if they appear in a spec literal, or if the `config:deprecated:true` is set directly or through the `--deprecated` flag. The optimization objective has also been removed, in favor of just ordering versions and having deprecated ones last.
This results in:
a) no delayed errors on install, but concretization errors when deprecated versions would be the only option. This is in particular relevant for CI where it's better to get errors early
b) a slight concretization speed-up due to fewer facts
c) a simplification of the logic program.
Co-authored-by: Harmen Stoppels <me@harmenstoppels.nl>
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