Consider Pure Nix

[nrdxp]

I've by no means run a thorough code analysis of the project, but I haven't seen anything yet that would make pure evaluation completely impossible. It is feasible that Nix, perhaps after CA derivations stabilize, could make pure evaluation mandatory, so it may be worth considering now whether the core segments could be refactored to work interchangeably with Nix Next, let's say, and Nix Stable.

[kamadorueda]

It's convenience only, for instance we added --impure on nix-unstable feature flag just to avoid fighting too much with this: https://github.com/fluidattacks/makes/issues/585

But I totally agree with you. Currently we are:

• fully --option sandbox true
• but with restrict-eval false (--impure on nix unstable) this is good enough with nix stable (as restrict eval as far as I know was created for hydra only), but definitely we should try to go all-in on restrict-eval true, for future releases on Nix

Thanks for pointing this out!