[bug#37305] Allow booting from a Btrfs subvolume [review part 2]

[Ludovic Courtès]

Hi Maxim,

Maxim Cournoyer <address@hidden> skribis:

>>> +              (error "The store is on a Btrfs subvolume, but the \
>>> +subvolume name is unknown.
>>> +Hint: Define the \"btrfs-subvolume-path\" file system property or
>>> +use the \"subvol\" Btrfs file system option."))))
>
>> Rather use ‘raise’ with ‘&message’ and ‘&fix-hint’ conditions.
>
> I tried this, but importing (guix utils) to acces &fix-hint caused the init
> RAM disk to fail mysteriously:

Oh, my bad.  We should move ‘&fix-hint’ to (guix diagnostics)
eventually.

In the meantime, I’d say just raise a ‘&message’ and leave the hint as a
comment (it’s not supposed to be a user-facing interface).  Or maybe you
could define a specific error condition type for this?

Thanks,
Ludo’.

PS: I’ll comment on the other bits ASAP!