Debug Spack “Error: failed to concretize” (v1)
The error messages provided by Spack when concretization fails can be difficult to understand. Some examples of error messages:
No valid value for variant 'deterministic' of package 'access-om2'
This error message can appear for many reasons. Further debugging may be required to ascertain the actual fault.
The first step is to see if the failure can be isolated to a single Spack Package Recipe (SPR) by concretizing/solving a single SPR at a time, while an environment is activated, by running spack solve <SPR>. e.g.
spack solve mom5
Is the concretizer’s unify setting True or False
The following command can be run inside our outside an environment to determine the setting of unify:
# spack config blame concretizer | grep unify
/opt/spack/etc/spack/defaults/base/concretizer.yaml:38 unify: True
Setting unify to false reduces the constraints during concretization and might help identify the root cause.