title: How to fork two git branches around failed merge
body: <p>I have the following situation in my git repository at the moment.</p>
  
  <pre><code>HEAD -- 0 -- 1 -- ... -- 3 -- 5 master
           \-- 2 -- ... -- 4 --/  branch-1
  </code></pre>
  
  <p>The branch "branch-1" has been forked from the master some time ago (see commit 5). </p>
  
  <p>At commit 0 I wanted to merge it back to master but all changes that had happened in master between commits 1 and 3 were overwritten. Effectively creating</p>
  
  <pre><code>0 -- 2 -- ... -- 4 -- 5 master
  </code></pre>
  
  <p>Since my colleagues could not continue their work on this state I have reverted the merge commit. Thus I did set HEAD to be the same as 1. The command used would be "git revert -m 2 0".</p>
  
  <p>But now I would like my changes merged back in again. This time I hope it will be successful. I need to create something like:</p>
  
  <pre><code>-2 -- HEAD -- 0 -- 1 -- ... -- 3 -- 5 master
    \            \-- 2 -- ... -- 4 --/
     \--- -1 ------/
  </code></pre>
  
  <p>This would be a new commit -1 that avoids the failed merge 0 and goes back in at the clean state I had (the clean state I achieved by reverting) prior to the merge.</p>
  
  <p>However just trying to merge 2 to HEAD does not work. I think this is because they are already merged at 0.</p>