Bug#660889: apt: apt-cache -- Does not return correct status code

[Jari Aalto <jari.aalto@cante.net>]

Package: apt
Version: 0.8.15.9
Severity: normal

Problem:

	$ apt-cache policy nothing-to-find ; echo $?
	N: Unable to locate package nothing-to-find
	0

Program should return non-zero status. The current behavior disalows
using call in shell programs:

	if ! apt-cache policy $package ; then
      	   echo "Invalid package name: $package" >&2
	   return 1
	fi

-- System Information:
Debian Release: wheezy/sid
  APT prefers unstable
  APT policy: (990, 'unstable')
Architecture: i386 (i686)

Kernel: Linux 3.2.0-1-686-pae (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash

Versions of packages apt depends on:
ii  debian-archive-keyring  2010.08.28
ii  gnupg                   1.4.11-3
ii  libc6                   2.13-26
ii  libgcc1                 1:4.6.2-14
ii  libstdc++6              4.6.2-14
ii  zlib1g                  1:1.2.6.dfsg-1

apt recommends no packages.

Versions of packages apt suggests:
ii  apt-doc         <none>
ii  aptitude        0.6.5-1
ii  bzip2           1.0.6-1
ii  dpkg-dev        1.16.1.2
ii  python-apt      0.8.3+nmu1
ii  xz-lzma [lzma]  5.1.1alpha+20110809-3

-- no debconf information