Bug#682365: dpkg: native package in rc state prevents installation of m-a:foreign counterpart

[Jonathan Nieder <jrnieder@gmail.com>]

Guillem Jover wrote:
> On Sat, 2012-07-21 at 22:30:30 -0500, Jonathan Nieder wrote:

>> What dpkg commands should apt run to upgrade from this state?
>
> In this particular case, apt would need to check that there's no multiple
> instances present if the new package is switching from M-A:same to
> non-M-A:same. And in that case notify the user that the package instance
> in config-files state would need to be purged.

Makes sense.  Thanks for explaining.

This idea of purging one arch of a package while keeping other arches
is still new to me.

+ Most libraries' post-removal scripts run 'ldconfig' on removal and
  do nothing on purge, which should work fine.

+ "libc6.postrm purge" runs db_purge.  The corresponding 'owner' is
  arch-qualified, making this safe.

+ Likewise for libpam0g, libpam-modules, libssl1.0.0, etc.

? "libc6-i686.postrm remove" and other optimized libc packages use
  dpkg-query -l to find the version of all optimized libc packages.
  The parsing does not take the colon in "Multi-Arch: same" packages
  into account, so it never notices that all have been upgraded in
  order to remove /etc/ld.so.nohwcap.

+ libgdk-pixbuf2.0-0.postrm is a model citizen.

+ libglib2.0-0.postrm purges some caches that are not
  architecture-specific.  This is probably harmless because they are
  caches.

- libgphoto2-2.postrm purges .dpkg-bak files representing user
  customized obsolete configuration files without checking if another
  arch is staying around to take responsibility for them.

- "libgtk-2.0-0.postrm purge" wipes out /etc/gtk-2.0/*

- likewise for libgtk-3-0

- "liblockfile1.postrm remove" wipes out its documentation directory
  (!)

- "libpaper1.postrm purge" removes /etc/papersize and the
  corresponding ucf configuration

- "libuuid1.postrm purge" removes /var/lib/libuuid

- "libwrap0.postrm purge" removes /etc/hosts.{allow,deny}

- "libzvbi0.postrm purge" removes /etc/default/libzvbi0

Those are just the libraries I currently have installed on the machine
I am using to type this.

I guess a "general" bug is in order.

Jonathan