Bug#265641: apt: uninstalled, pinned packages hide packages from available list

[Joshua Neal <jneal@csdaily.com>]

Package: apt
Version: 0.5.27
Severity: normal


If you have packages pinned in /etc/apt/preferences, and those packages
are not installed, then apt-cache will silently remove that package from
its list of available packages (as in the 'apt-cache dumpavail' option),
and apt-get install will declare that the package is not available.  Yet
frustratingly enough, 'apt-cache show' will display the package
information and 'apt-get source' will work happily.  

I understand this is probably correct behavior, but in my case these
entries were added to /etc/apt/preferences by apt-listbugs long ago, so
it was entirely non-obvious as to why it was not working.

Example from /etc/apt/preferences:

Explanation: Pinned by apt-listbugs at Fri Jan 30 02:08:57 PST 2004
Package: wine
Pin: version 0.0.20030813-2
Pin-Priority: 1000



-- Package-specific info:

-- System Information:
Debian Release: 3.1
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: i386 (i686)
Kernel: Linux 2.4.26-1-686
Locale: LANG=C, LC_CTYPE=C

Versions of packages apt depends on:
ii  libc6                       2.3.2.ds1-16 GNU C Library: Shared libraries an
ii  libgcc1                     1:3.4.1-5    GCC support library
ii  libstdc++5                  1:3.3.4-7    The GNU Standard C++ Library v3

-- no debconf information