Make eval restriction an option instead of forcing

[dasJ]

[Ma27]

Might make sense to leave a note in e.g. doc/manual/src/installation.md, but LGTM :+1:

[dasJ]

I wanted to document it next to the other evaluator options but they are not documented either :laughing:

[kquick]

It seems like this would result in un-reproducible builds and builds that can be dependent on elements not captured in the store or the derivation?

[dasJ]

Yes

[kquick]

Maybe you could say more about what problem this addresses, because a CI testing system that doesn't generate builds that are reproducible or stable doesn't seem ... useful?

[ajs124]

AFAIR this enables IFD.

Edit: https://github.com/NixOS/nix/issues/1888#issuecomment-370242344

[grahamc]

I am not thrilled that such an inauspicious PR got such an auspicious number.

[dasJ]

Any updates on this? I don't really see why this would not be an option. cc @grahamc