Re: guix system delete-generations -- advice?

[ludo@gnu.org (Ludovic Courtès)]

Hi Thomas, and apologies for the delay!

Thomas Danckaert <post@thomasdanckaert.be> skribis:

> I added `guix system delete-generations' in my git checkout, WIP patch
> attached.  I had started to adapt the corresponding code from `guix
> package delete-generations', but then realized that
> `delete-matching-generations` from (guix scripts package) contains
> everything that's needed (could it be moved to (guix ui)?).
>
> One thing I'm not satisfied with is this: `reinstall-grub' does not
> reproduce custom grub menu entries added in the (grub-configuration)
> section of a system's bootloader configuration.  So users with a
> dual-boot system lose theire non-GuixSD grub entries after running
> “guix system delete-generations” (until they run “guix system
> reconfigure” again).  The existing “guix system switch-generation” has
> the same problem.
>
> Is there a way to retrieve the current custom grub entries, other than
> providing a system configuration, or, I hardly dare say it out loud,
> parsing grub.cfg? How could this be improved?

Very good point, it’s really a shortcoming.

To fix it we could add the extra entries to <boot-parameters> (which
you can see as /run/current-system/parameters.)  See what I mean?

As for how to proceed, I’m fine either way: we could commit your ‘guix
system delete-generation’ patch first, with the understanding that it
has the bug you describe, and then fix the bug; or we could do it the
other way around.

WDYT?

> ps I also noticed that passing an empty string ("") as a command line
> argument to many guix commands returns a guile backtrace, e.g. guix
> system list-generations "". I find this a little messy, or is it a
> feature?

Doh!  It’s a bug in Guile’s (srfi srfi-37).  Could you send it to
bug-guile@gnu.org?

Thanks!

Ludo’.