Re: Determinism issue

[Ludovic Courtès]

Hello,

Roughly, there’s not much difference between what Guix and Nixpkgs
provide in terms of build determinism, but this is clearly something
we’re interested in.

Guix may be slightly stricter in that chroot builds are the default, and
it doesn’t rely on /bin/sh being in the chroot (unlike Nixpkgs.)

You mention profile-guided optimizations.  This is *disabled* by default
in GCC, AFAIK, so GCC is definitely deterministic.

Another thing we do is build Binutils with
--enable-deterministic-archives, which makes ‘ar’ archives with zeroed
timestamps by default.

For other examples of non-determinism issues, the Debian project has a
nice summary: <https://wiki.debian.org/ReproducibleBuilds>.

Similarly, some time ago, I started looking a fixed-point builds, though
I didn’t complete that:

  https://lists.gnu.org/archive/html/guix-devel/2013-09/msg00159.html

Thanks,
Ludo’.