title: Git: Merge again from previous branch
body: <p>Is it possible to Merge from a previous branch and resolve conflicts with the current branch?</p>
  
  <p>I have a scenario where a colleague could not access our remote repository, and so had to make changes to files in a copy of the project. I now wish to merge these files in a new branch back into the project; however, there has been other work on these files as well.</p>
  
  <p>I considered branching off from an up-to-date master, clobbering the old files in the new branch with the colleague's work, and then remerging from the head of the previous branch. Ideally, I'd then be able to go through manually confirming conflicts. This would have a structure somewhat like:</p>
  
  <pre><code>           o-------o-------o-------o
            /               /         \
           /               /           \
  --------o---------------+-------------o-----&gt;
  </code></pre>
  
  <p>where there have been no changes to the original branch at the + where I want to merge from here to the new branch.</p>
  
  <p>When I attempt a Merge From from the original branch, I get "All files are up to date".</p>
  
  <p>EDIT:
  The actual structure of the edits is a little different from the image above, it's closer to:</p>
  
  <pre><code>------A-----B--------+----&gt;   dev branch
        |      \        \
        |       B'---C`--D--&gt;   new branch with changes
        |
        A`----C                 changes made outside Git
  </code></pre>
  
  <p>where A` is a copy of the project at A, B are changes I've made within Git, C are changes my colleague made outside Git, and C` is the state of the branch once I've copied his changes in. D is the resulting merge back from the original branch in which I wish to pick conflicts.</p>
  
  <p>However, instead of D, I'm just getting C, no change. I believe this might be because the state of the branch at copying is B, and hence Git just sees the new files as a simple set of adds and deletes, nothing difficult to resolve automatically.</p>