title: Local branch lost remote tracking branch
body: <p>I have a strange situation I haven't encountered before.</p>
  
  <p>I've just done git fetch gotten updates for both my develop and master branches:</p>
  
  <pre><code>From remote-host:my_repo
     f3946b5..c3b2d44  develop    -&gt; origin/develop
     72830fe..14d8be6  master     -&gt; origin/master
  </code></pre>
  
  <p>Git status on my master branch correctly reports that I'm behind.  However, on my develop branch, there's no indication that I'm behind:</p>
  
  <pre><code>dumbo:my_repo wade$ git checkout develop
  Switched to branch 'develop'
  dumbo:my_repo wade$ git status
  # On branch develop
  nothing to commit (working directory clean)
  </code></pre>
  
  <p>I determined that it's because my local develop branch is no longer tracking origin/develop:</p>
  
  <pre><code>dumbo:my_repo wade$ git branch -avv
   * develop                   24f29e2 Updated config
    master                    60d5d8f [origin/master: behind 109] Deploy w/ session_fix
    remotes/origin/HEAD       -&gt; origin/master
    remotes/origin/develop    c3b2d44 Deploy changes
    remotes/origin/master     14d8be6 Deploy changes
  </code></pre>
  
  <p>Now, I know I can fix it with git branch --set-upstream, but my question is, how did it get clobbered?  I certainly didn't take any conscious action to delete the remote tracking association.</p>
  
  <p>My normal workflow is:</p>
  
  <pre><code>  (on branch develop)
    git stash (if necessary)
    git fetch
    git merge or git rebase origin/develop
    git checkout master
    git merge origin/master
    git checkout develop
  </code></pre>
  
  <p>Any thoughts on what actions would cause a tracking branch association to get clobbered?</p>