title: Install packages from the Debian Snapshot Archives repo?
body: <p>The <a href="http://snapshot.debian.org/" rel="nofollow">Debian Snapshot Archive</a> describes being able to add the snapshot repositories into <code>/etc/apt/sources.list</code> so that one can install debian binaries using <code>apt-get</code> directly from the archive.  </p>
  
  <p>This sounds straight-forward.  However, when I configure a vanilla Debian machine as described with <code>sources.list</code> pointing to the snapshot versions of the repos, <code>apt-get install</code> refuses to install the dependencies. For example, the call:</p>
  
  <pre><code> apt-get -o Acquire::Check-Valid-Until=false update \
   &amp;&amp; apt-get install -y --no-install-recommends r-base
  </code></pre>
  
  <p>Results in the error:</p>
  
  <pre><code>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:
   r-base : Depends: r-base-core (&gt;= 2.11.1-6) but it is not going to be installed
            Depends: r-recommended (= 2.11.1-6) but it is not going to be installed
            Recommends: r-base-html but it is not going to be installed
  E: Broken packages
  </code></pre>
  
  <p><code>apt-cache show r-base-core</code> etc show the requested packages and versions exist, so it's not clear why it does not simply install them.  </p>
  
  <p>It is easy to illustrate this problem using a Dockerfile, <a href="https://github.com/rocker-org/rocker-versioned/tree/master/binary/2.12.0-repo" rel="nofollow">like this</a>, in order to attempt installing debian packages on a vanilla Debian release from any computer running docker. </p>
  
  <p>I note that installing from the snapshot archives works just fine if I grab the specific <code>.deb</code> files from the Snapshot Archive (e.g. <a href="https://github.com/rocker-org/rocker-versioned/tree/master/binary/2.12.0/Dockerfile" rel="nofollow">this dockerfile</a>), but clearly that is not the intended method outlined on the <a href="http://snapshot.debian.org/" rel="nofollow">Debian Snapshot Archive</a> which says to just add the repos to <code>souces.list</code>.</p>