title: Why doesn't git merge changes when two branches are different but with no new commits in either branch?
body: <p>For example,</p>
  
  <p>I my master branch has stuff in it. Another branch called <code>other_branch</code> has stuff+more_stuff in it. Each branch has nothing to commit.</p>
  
  <p>If I checkout master then try to merge other_branch, git says "Already up-to-date." and nothing happend. why won't more_stuff be merged into master in this case? Is that how git was designed?</p>
  
  <p>NOTE: other_branch was created from an older commit of master.</p>