[Pkg-utopia-maintainers] Bug#717613: systemd-udevd failes to execute /lib/udev/socket:@/org/freedesktop/hal/udev_event

[David Kalnischkies]

On Thu, Jan 30, 2014 at 05:51:44PM +0100, Michael Biebl wrote:
> Am 30.01.2014 17:32, schrieb Martin Pitt:
> > Michael Biebl [2014-01-30 17:24 +0100]:
> >> c/ Add Breaks: hal to udev so it is automatically uninstalled on Linux.
> >> Since hal on Linux is no longer really functional and actually broken by
> >> that udev change, this might be the right thing to do.
> >> 
> >> I'm usuallly a bit wary with adding Breaks since they have the tendency
> >> to confuse apt on dist-upgrades.
> 
> > I concur. I've been pondering doing the same on Ubuntu as we still get
> > the odd bug report about it as well (and we entirely removed hal some
> > time ago). Would a Breaks:/Replaces: help out apt more than a single
> > Breaks:?
> 
> Dunno, using Replaces seems a bit odd here.

Replaces will do exactly nothing in APT, so don't add it if you don't
replace files and want to tell dpkg about it (and please tell this
anyone you meet, as it is a common misunderstanding).


> That said, since udev is a rather central package it's highly unlikely
> that this Breaks would cause udev to be uninstalled.

The problem is not so much that APT could decide to remove udev as a
"better" solution exists: hold udev at its installed version
(especially as hal itself depends on udev).

That said, it is unlikely that it will happen. On my system udev has a
score of 86 points¹ at the moment. That doesn't make it invincible,
but should win against an obsolete package easily (which at most has
some points left from other obsolete packages) – especially as this
obsolete package depends on udev itself, so the score it has gets also
added to udev…

¹ apt-get dist-upgrade -s -o Debug::pkgProblemResolver::ShowScores=1 2>&1 | grep ' udev '
  [I somehow suspect for most people, the score is (a lot) higher.]

(Removing hal from the archive would btw only lower the score by one
 point for hal, so it is not that effective from an APT point of view.
 And its not that effective as a hint anyway as many people have also
 older sources in their list, so packages are never not downloadable)


> IIRC the general recommendation is to *not* use Breaks to kick out
> obsolete packages but instead let "apt-get autoremove" cleanup such
> packages.

This is indeed the preferred way as beside that APT could decide against
the remove based on the score you could also have a *user* deciding
against a remove. Some actually check before saying 'Y' and frankly, the
description of hal would suggest at least to me that it might not be a
clever idea to let it go without deeper investigation…
(but maybe I am just too used to unstable).


> But in this case not kicking out hal forcefully leads to those
> scary boot messages (and already quite a few duplicate bug reports).
> Once this udev version enters stable, we might get even more.
> So I'm also inclined to add the Breaks.

Usually I would suggest a transitional package in addition, but in this
case I am going a bit further:
The error message suggests to me (who has absolutely no idea what he is
talking about through) that hal configures udev to send messages to hal.
Why not just drop this configuration if it doesn't work anyway… ?


Best regards

David Kalnischkies
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