Bug#277890: xutils: file conflict with xbase-clients 4.3.0.dfsg.1-8

[Andrew Pimlott <andrew@pimlott.net>]

On Mon, Oct 25, 2004 at 01:46:30PM -0500, Branden Robinson wrote:
> 
> On Sat, Oct 23, 2004 at 02:44:05AM -0400, Andrew Pimlott wrote:
> > Package: xutils
> > Version: 4.1.0-16woody3
> > Severity: minor
> > 
> > When upgrading xutils on my mixed stable/unstable system, I got
> > 
> >     Preparing to replace xutils 4.1.0-16woody3 (using .../xutils_4.1.0-16woody4_i386.deb) ...
> >     Unpacking replacement xutils ...
> >     dpkg: error processing /var/cache/apt/archives/xutils_4.1.0-16woody4_i386.deb (--unpack):
> >      trying to overwrite `/usr/X11R6/bin/atobm', which is also in package xbase-clients
> > 
> > This is evidently because I have xbase-clients 4.3.0.dfsg.1-8 installed.
> > 
> > No worries if you don't want to support this configuration.
> 
> This is not something I think I *can* fix.
> 
> I don't think xutils Replaces: xbase-clients (<= 4.3.0.dfsg.1-7) is
> something that makes sense to add to woody, nor do I think Martin Schulze
> would accept such a change.
> 
> If there is a fix for this, it lies in dpkg.  Every time even one package
> is upgraded, dpkg would have to rescan the Replaces: headers of all
> already-installed packages to see if this error would be suppressed by one
> of them.  It could do this on a per-run basis, I suppose, so it would only
> be inefficient if you used dpkg a lot to upgrade only one package at a time.

Ok, I see that my current xbase-clients has

    Replaces: xutils (<< 4.3.0.dfsg.1-7)

I had assumed that this (or something similar) was missing
xbase-clients, so that there would be a simple resolution.  I now
understand why this isn't sufficient (though it was entirely non-obvious
to me).  The implicit assumption is that a Replaced package will not be
upgraded to one that still contains the overwritten file.  Interesting.

I agree that you don't have any palatable option.  However, I think dpkg
could handle this without any performance hit.  All it has to do is,
after detecting an attempted overwrite, see whether the existing owner
of the file Replaces the package being installed.  (This won't handle a
change of two Replaces, but ...)

(Obviously, I should have filed the bug on xbase-clients if I had really
thought this through.)

Andrew

[1] http://www.debian.org/doc/debian-policy/ch-relationships.html#s-replaces