bug#47748: Packages which cant be find/removed by guix remove

[bo0od <bo0od@riseup.net>]

Great, I believe you got my message clearly thank you as well for the 
commands.

yes in debian if you want to remove libavahi it wont be removed (without 
breaking stuff), but avahi-daemon (if its installed) you can remove it 
with no issues so as wpa-supplicant,mesa..etc

Anyway you just got my message clearly and i appreciate that <f>.

Mark H Weaver:
> bo0od <bo0od@riseup.net> writes:
> 
>>   > You seem to want it to do something different than it was intended to
>>   > do, although I'm not precisely sure what that is.  Do you want it to try
>>   > to purge all copies of the given package from /gnu/store?  If so, that
>>   > might require deleting (or modifying) older system generations and older
>>   > user profiles, which would interfere with rollback functionality.
>>
>> Isnt this the standard understanding of deleting a package whether in
>> GNU/Linux or Windows or Mac? If user has the root rights he should be
>> able to delete software x,
> 
> The command in Guix that most closely matches what you seem to be asking
> for is "guix gc --delete", which will try to delete a given set of store
> items.  In your original bug report, it looks like 'avahi' was one of
> the things you were trying to remove, so I'll use that as an example:
> 
> --8<---------------cut here---------------start------------->8---
> mhw@jojen ~$ guix gc --delete /gnu/store/…-avahi-0.8
> finding garbage collector roots...
> guix gc: error: cannot delete path `/gnu/store/…-avahi-0.8' since it is still alive
> --8<---------------cut here---------------end--------------->8---
> 
> If you get this error, you can use "guix gc --referrers" to find out
> what's keeping it alive:
> 
> --8<---------------cut here---------------start------------->8---
> mhw@jojen ~$ guix gc --referrers /gnu/store/…-avahi-0.8
> /gnu/store/…-geoclue-2.5.7
> /gnu/store/…-gvfs-1.40.2
> /gnu/store/…-pulseaudio-14.0
> /gnu/store/…-cups-filters-1.27.4
> /gnu/store/…-guile-avahi-0.4.0-1.6d43caf
> /gnu/store/…-avahi-0.8
> /gnu/store/…-cups-2.3.3
> /gnu/store/…-grilo-plugins-0.3.11
> --8<---------------cut here---------------end--------------->8---
> 
> So, it looks like I won't be able to remove avahi from my store, at
> least not if I want to keep GNOME, CUPS, or Pulseaudio.
> 
> For similar reasons, I can't remove Avahi from my Debian server either:
> 
> --8<---------------cut here---------------start------------->8---
> root@world:~# dpkg -r libavahi-client3
> dpkg: dependency problems prevent removal of libavahi-client3:amd64:
>   libvirt0:amd64 depends on libavahi-client3 (>= 0.6.16).
>   libcups2:amd64 depends on libavahi-client3 (>= 0.6.16).
> 
> dpkg: error processing package libavahi-client3:amd64 (--remove):
>   dependency problems - not removing
> Errors were encountered while processing:
>   libavahi-client3:amd64
> --8<---------------cut here---------------end--------------->8---
> 
> Anyway, I agree that it would be good to have a user-friendly way to ask
> Guix why a given piece of software is in their store, and to help them
> find ways to remove it, if possible.  We have some tools to help with
> this, e.g. "guix gc --referrers", "guix graph --type=reverse-package",
> "guix graph --type=reverse-bag", and "guix graph --path", etc, but
> there's plenty of room for improvement.
> 
>        Mark
>