apt-get has again broken dependency logic:

xvii:~> apt-get install ruby1.8 -s
NOTE: This is only a simulation!
      apt-get needs root privileges for real execution.
      Keep also in mind that locking is deactivated,
      so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  fonts-gfs-baskerville fonts-gfs-bodoni-classic fonts-gfs-didot-classic
  fonts-gfs-gazis fonts-gfs-porson fonts-gfs-theokritos fonts-hosny-amiri
  latex-sanskrit lcdf-typetools m-tx musixtex pmx texlive-formats-extra
  texlive-games texlive-lang-african texlive-lang-arabic texlive-lang-cjk
  texlive-lang-czechslovak texlive-lang-english texlive-lang-european
  texlive-lang-german texlive-lang-greek texlive-lang-indic
  texlive-lang-italian texlive-lang-polish texlive-lang-portuguese
  texlive-lang-spanish texlive-music texlive-omega texlive-plain-extra
  texlive-publishers texlive-publishers-doc
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
  libruby1.8
Suggested packages:
  ruby1.8-examples ri1.8 ruby-switch
The following packages will be REMOVED:
  context context-modules texlive-full
The following packages will be upgraded:
  libruby1.8 ruby1.8
2 upgraded, 0 newly installed, 3 to remove and 7 not upgraded.
Remv texlive-full [2013.20130905-1]
Remv context-modules [20130702-1]
Remv context [2013.05.28.20130704-3]
Inst ruby1.8 [1.8.7.358-7.1] (1.8.7.358-8 Debian:unstable [amd64]) []
Inst libruby1.8 [1.8.7.358-7.1] (1.8.7.358-8 Debian:unstable [amd64])
Conf libruby1.8 (1.8.7.358-8 Debian:unstable [amd64])
Conf ruby1.8 (1.8.7.358-8 Debian:unstable [amd64])

i.e. apt-get wants to remove context and texlive-full, while it
shouldn't be necessary. Let's prevent texlive-full removal:

xvii:~> apt-get install ruby1.8 texlive-full -s
NOTE: This is only a simulation!
      apt-get needs root privileges for real execution.
      Keep also in mind that locking is deactivated,
      so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
texlive-full is already the newest version.
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 texlive-full : Depends: context but it is not going to be installed
E: Unable to correct problems, you have held broken packages.

and same problem without the -s option as root. I wonder why I get
an error here, since context is already installed and doesn't need
to be upgraded:

xvii:~> apt-get install ruby1.8 texlive-full context -s
NOTE: This is only a simulation!
      apt-get needs root privileges for real execution.
      Keep also in mind that locking is deactivated,
      so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
context is already the newest version.
context set to manually installed.
texlive-full is already the newest version.
The following extra packages will be installed:
  libruby1.8 ruby ruby1.9.1
Suggested packages:
  ri ruby-dev ruby1.8-examples ri1.8 ruby-switch ruby1.9.1-examples ri1.9.1
  ruby1.9.1-dev
The following NEW packages will be installed:
  ruby ruby1.9.1
The following packages will be upgraded:
  libruby1.8 ruby1.8
2 upgraded, 2 newly installed, 0 to remove and 7 not upgraded.
Inst ruby1.8 [1.8.7.358-7.1] (1.8.7.358-8 Debian:unstable [amd64]) [context:amd64 ]
Inst libruby1.8 [1.8.7.358-7.1] (1.8.7.358-8 Debian:unstable [amd64]) [context:amd64 ]
Inst ruby1.9.1 (1.9.3.448-1 Debian:testing [amd64]) [context:amd64 ]
Inst ruby (1:1.9.3 Debian:7.1/stable, Debian:testing, Debian:unstable [all])
Conf libruby1.8 (1.8.7.358-8 Debian:unstable [amd64])
Conf ruby1.8 (1.8.7.358-8 Debian:unstable [amd64])
Conf ruby1.9.1 (1.9.3.448-1 Debian:testing [amd64])
Conf ruby (1:1.9.3 Debian:7.1/stable, Debian:testing, Debian:unstable [all])

I've attached the /var/lib/dpkg/status file, compressed with xz.