spack:
  specs:
  - python @3.10+libxml2+tkinter %[email protected]
  view: true
  concretizer:
    unify: true

fmm@spack>spack -e testpy concretize -f
==> Error: concretization failed for the following reasons:

   1. Cyclic dependency detected between 'xcb-proto' and 'xcb-proto' (consider changing variants to avoid the cycle)
   2. Cyclic dependency detected between 'xcb-proto' and 'tk' (consider changing variants to avoid the cycle)
   3. Cyclic dependency detected between 'xcb-proto' and 'python' (consider changing variants to avoid the cycle)
   4. Cyclic dependency detected between 'xcb-proto' and 'libxcb' (consider changing variants to avoid the cycle)
   5. Cyclic dependency detected between 'xcb-proto' and 'libx11' (consider changing variants to avoid the cycle)
   6. Cyclic dependency detected between 'tk' and 'xcb-proto' (consider changing variants to avoid the cycle)
   7. Cyclic dependency detected between 'tk' and 'tk' (consider changing variants to avoid the cycle)
   8. Cyclic dependency detected between 'tk' and 'python' (consider changing variants to avoid the cycle)
   9. Cyclic dependency detected between 'tk' and 'libxcb' (consider changing variants to avoid the cycle)
   10. Cyclic dependency detected between 'tk' and 'libx11' (consider changing variants to avoid the cycle)
   11. Cyclic dependency detected between 'python' and 'xcb-proto' (consider changing variants to avoid the cycle)
   12. Cyclic dependency detected between 'python' and 'tk' (consider changing variants to avoid the cycle)
   13. Cyclic dependency detected between 'python' and 'python' (consider changing variants to avoid the cycle)
   14. Cyclic dependency detected between 'python' and 'libxcb' (consider changing variants to avoid the cycle)
   15. Cyclic dependency detected between 'python' and 'libx11' (consider changing variants to avoid the cycle)
   16. Cyclic dependency detected between 'libxcb' and 'xcb-proto' (consider changing variants to avoid the cycle)
   17. Cyclic dependency detected between 'libxcb' and 'tk' (consider changing variants to avoid the cycle)
   18. Cyclic dependency detected between 'libxcb' and 'python' (consider changing variants to avoid the cycle)
   19. Cyclic dependency detected between 'libxcb' and 'libxcb' (consider changing variants to avoid the cycle)
   20. Cyclic dependency detected between 'libxcb' and 'libx11' (consider changing variants to avoid the cycle)
   21. Cyclic dependency detected between 'libx11' and 'xcb-proto' (consider changing variants to avoid the cycle)
   22. Cyclic dependency detected between 'libx11' and 'tk' (consider changing variants to avoid the cycle)
   23. Cyclic dependency detected between 'libx11' and 'python' (consider changing variants to avoid the cycle)
   24. Cyclic dependency detected between 'libx11' and 'libxcb' (consider changing variants to avoid the cycle)
   25. Cyclic dependency detected between 'libx11' and 'libx11' (consider changing variants to avoid the cycle)