title: How come bzr says there is nothing to do on merging branches that differ one from another?
body: <p>I have a bizarre situation with two bzr branches. The two branches differ one from another as can be seen here:</p>
  
  <pre><code>$bzr diff --old=/path/to/another/branch | wc -l
  148
  </code></pre>
  
  <p>However,  when I'm trying to merge these two branches, bzr says that there is nothing to do:</p>
  
  <pre><code>$bzr merge --preview /path/to/another/branch
  Nothing to do
  </code></pre>
  
  <p>I tried to <code>touch</code> the files in the another branch in order to modify their modification times, but this didn't help.
  What am I missing here? </p>