I found that “guix build python2-matplotlib -n” triggers a seemingly infinite loop (either uses of ‘package-with-python2’ somehow introduce cycles, or they lead to very large DAGs), which is what is causing Hydra evaluation failures.
I tried reverting 25f9a0 but it doesn’t help. Could you try to bisect it and revert or fix the problem? If it turns out to require more time, could you just comment out the offending parts of python.scm so Hydra can resume? Thanks in advance, and apologies for not noticing earlier! Ludo’.
