Re: Broke /etc/apt/preferences when trying to use just one package from unstable.

[Florian Kulzer <florian.kulzer+debian@icfo.es>]

On Sat, Jul 26, 2008 at 12:51:42 +0100, James Youngman wrote:
> I modified /etc/apt/{preferences,sources.list} to get just
> flashplugin-nonfree from unstable.      That seemed to work.
> However, now I find that  "apt-get install libsdl1.2-dev" results in
> this error:
> 
> # apt-get install libsdl1.2-dev
> Reading package lists... Done
> Building dependency tree
> Reading state information... Done
> Package libsdl1.2-dev is not available, but is referred to by another package.
> This may mean that the package is missing, has been obsoleted, or
> is only available from another source
> E: Package libsdl1.2-dev has no installation candidate
> 
> Could somebody take a look at my preferences and sources.list files
> and explain to me what I broke and how?    I attach both files
> (/etc/apt/sources.list.d is empty).

Your apt_preferences has multiple matches for certain repositories and
your last two rules put the priority of more or less everything to -1. I
am not surprised that apt starts to become weird.

Your goal can be achieved much simpler, with just one rule in
preferences:

Package: *
Pin: release a=unstable
Pin-Priority: 1

This means that testing will normally be preferred to unstable (unless
you ask for a package that is not in testing yet). In other words, you
can upgrade your testing system like before, and whenever you want one
or more packages from unstable you can call apt-get with "-t unstable",
e.g.:

apt-get -t unstable install flashplugin-nonfree

-- 
Regards,            | http://users.icfo.es/Florian.Kulzer
          Florian   |