Re: Guix release broken without substitutes on ungrafted openssl

[Simon Tournier <zimon.toutoune@gmail.com>]

Hi,

On Wed, 15 Feb 2023 at 13:33, Leo Famulari <leo@famulari.name> wrote:

> I'd guess it's happened 4 times in the last several years.
>
> It's one of several reasons that rebuilding old Guix releases actually
> approaches being a Hard Problem.

The issue is from the impure world. ;-)

Well, yeah it would probably be difficult to install from scratch Guix
v1.0 in some future.

However, the hope is that,

    guix time-machine --commit=v1.0 -- <command>

using distant future Guix to run <command> from Guix v1.0.  The distant
future Guix should be able to deal with the distant future impure world
and populate for the past <command> running inside a pure world.

For sure, it is a Hard Problem.  As I like to say when presenting “guix
time-machine”, it is a real world experiment, probably unique, to know
what is the size of the time frame where reproducible time-travel is
possible.  I try to explain that this reproducible time-travel requires
three conditions:

 1. source code availability
 2. Linux kernel compatibility
 3. hardware compatibility

Now, I would add:

 4. being able to communicate with the world via the network


Cheers,
simon