Steps to reproduce

Activate the following environment:

spack:
  specs:
  - zlib-ng
  - [email protected] ~mpi
  - zlib-ng generator=make
  view: false
  concretizer:
    unify: true

and concretize it:

$ spack concretize
[ ... ]

Then deconcretize hdf5 and reconcretize:

$ spack deconcretize hdf5
$ spack concretize

Error message

During the last command an assertion error is enmitted:

$ spack concretize 
==> Error: literal specs have different requirements. clear cache before computing literals

The trigger is, in general:

• Have 2 or more user specs that map to the same concrete spec on a first concretization
• Deconcretize something else, and try to reconcretize the environment

Information on your system

• Spack: 0.22.0.dev0 (5299b84)
• Python: 3.11.5
• Platform: linux-ubuntu20.04-icelake
• Concretizer: clingo

General 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
• I have run the failing commands in debug mode and reported the output