[gentoo-user] --depclean and openrc [Was: Wayland! Beware of!]

[Alan Mackenzie <acm@muc.de>]

Hello, Eli.

On Mon, Sep 23, 2024 at 18:54:50 -0400, Eli Schwartz wrote:
> On 9/23/24 6:08 PM, Alan Mackenzie wrote:
> >> Do you have that little faith in the Gentoo Developers, that you think
> >> we'd make a USE flag change that made everyone's systems suddenly break?

> > It happens, from time to time, by accident.  For example, emerge
> > --depclean on my system wants to unmerge openrc.  Not a deliberate
> > move by the developers, just some accident.  But it's the reason I
> > don't do emerge --depclean, ever.

> This should not generally be possible. The @system set contains
> virtual/service-manager, so you cannot depclean that.

It is very much possible, and it happens.  The mechanism is understood,
you've outlined it below.

[ .... ]

> So, @system requires you to have any one of:

> - openrc
> - openrc-navi (a testing fork with openrc user services)
> - s6
> - systemd
> - runit
> - daemontools

> It's possible you have installed another one of these packages too. If
> you do, then virtual/service-manager will still be satisfied, and it
> will allow you to depclean openrc.

Yes, I have daemontools, needed as a component of a qmail variant.

> In theory, one should not have multiple init systems installed. And
> openrc is the preferred satisfier, so if you use `emerge --depclean` it
> will try to depclean the other package, not openrc. But you can depclean
> openrc itself in that case, since portage doesn't know which init system
> you intend to keep.

If I had invoked --depclean without the -a (or -p) flag, my system would
have had openrc removed, and it would have been unbootable.  This is the
sort of thing a new Gentoo user might do.

> Even in this case it emits a warning:

> !!! 'sys-apps/openrc' (virtual/service-manager) is part of your system
> profile.
> !!! Unmerging it may be damaging to your system.

So, having your system made unbootable is opt-out rather than opt-in.

> to make sure you are fully aware that you intend to depclean a package
> that *might* be the wrong one.

The context of this discussion was an implication that the Gentoo
maintainers wouldn't make a change "that made everyone's systems suddenly
break".  I submitted a bug report about --depclean back in the summer of
2021 (though I can't find that bug any more).  I think it was closed as
not-a-bug.

There are several ways this could have been fixed, for example with
--depclean preserving packages in system, as well as world.  But it was
regarded as not a bug.

So I think it is fair to say that the Gentoo developers are content for
some systems (in particular, mine) suddenly to break.  I am thus somewhat
sceptical about things in Gentoo which may be based on assumptions which
don't hold in my system.  The new +wayland USE flag kind of looked a bit
like that to me.  Actually, it wasn't, so I apologise for my opening
post.

> -- 
> Eli Schwartz

-- 
Alan Mackenzie (Nuremberg, Germany).