title: Command/steps for merging one branch into another more than once?
body: <p>I get "Already up-to-date" messages when trying to merge one branch, 'feature_1', into another, 'release_1', more than once where changes have been committed to feature_1 in between merges. That is, I have something like:</p>
  
  <pre><code># Developer 1: create feature_1 branch with initial commit
  git checkout -b feature_1 origin/master
  git commit -am "Initial commit."
  git push origin feature_1
  
  # Developer 2: create release_1 branch and merge feature_1 into it
  git checkout -b release_1 origin/master
  git merge origin/feature_1
  # success
  git push origin release_1
  
  # Developer 1: make change to feature_1
  git checkout feature_1
  git commit -am "Fixed issue."
  git push origin feature_1
  
  # Developer 2: attempt to get latest state of feature_1 merged into release_1
  git checkout release_1
  git merge origin/feature_1
  
  Already up-to-date 
  </code></pre>
  
  <p>From reading related questions ( <a href="https://stackoverflow.com/questions/634546/git-merge-mystery">Git merge reports &quot;Already up-to-date&quot; though there is a difference</a> and <a href="https://stackoverflow.com/questions/1402968/git-merge-confusion-diff-shows-differences-and-merge-says-there-are-none">Git merge confusion. Diff shows differences, and merge says there are none</a> ) I understand that this indicates that feature_1 is an ancestor of release_1. What I haven't found yet is how to merge/fast-forward the latest commits from feature_1 into release_1 that second time.</p>
  
  <p>From comments in the first question linked above I've tried the following while in release_1:</p>
  
  <pre><code>git reset --hard origin/feature_1
  </code></pre>
  
  <p>This essentially resets release_1 so that it's identical to the latest state of feature_1 rather than merging the latest state of both branches together, so that's not what I'm looking for.</p>
  
  <p>How can I merge the latest commits from feature_1 into release_1 if feature_1 is an ancestor of release_1? I thought 'git merge' would do a fast forward. I wonder if I'm missing a 'git pull' or something and the fast forward is not seeing the latest commit on the origin. Or if there's some other command/step I haven't found yet. Basically, am I using the correct approach and I'm just missing something (or maybe msysgit has bug) or am I using the wrong approach altogether?</p>
  
  <p>Thanks for your help.</p>