Re: Reproducible and deterministic builds for GNU Guix (and Nix)

[Pjotr Prins]

> also be changed). I guess you need it for hot reloading, but can't you
> calculate the SHA on the fly for that? You'd need to open beam files
> anyway to get the value(s) and they will be loaded by the OS unless

Aw, sorry Joe, my bad. The stored SHA value is calculated on the
original source file, so that is not opened. 

Guix/Nix calculate their SHA values over the source and build
environment and that path is stored in an immutable store. So, you
already have a strong guarantee that the sands don't shift under you. 

But then people will use Erlang outside GNU Guix - and there a SHA
value makes sense if you watn to have a guarantee that it has the same
source. Much better than a time stamp.

Pj.