bug#24993: System installer grows brittle with time

[Leo Famulari]

On Mon, Nov 28, 2016 at 08:45:39AM -0900, Christopher Howard wrote:
> I was able to make more progress with the --substitute-urls=... option
> you mentioned. However, later, when the system is building the
> gnupg-2.1.13 drv (I did not pass --fallback, but it still builds stuff)
> one of the 36 check tests fails ("tofu.test"), causing the build to fail.

It will build stuff if it can't find a substitute (not an error).
'--fallback' is only required when substitution fails (an error).

That particular test failure was a bug in GnuPG's test suite that we
worked around:

http://git.savannah.gnu.org/cgit/guix.git/commit/?id=d404a6f9711c8dcc1cc6cf55d8c07901aa450192

Code with an expiration date is very annoying!

It sounds like you will need to use `guix pull`.

What do others think? Should we mention `guix pull` in the installation
documentation?

I'm skeptical for reasons described upthread. I think the real bug is
that the installation image becomes brittle as time passes (so I changed
the subject of my reply).

Does anyone have ideas to mitigate this? Can we tweak the mirrors? Will
this become less pressing when we have more storage space and can store
substitutes for a longer period?