title: git merging master into task branch is removing code
body: <p>I am seeing issues when merging the master into a task branch where code in the master is being removed when merging into the task branch.</p>
  
  <p>Example:
  I have multiple developers working on their own branches all of which have a common ancestry from the master.</p>
  
  <p>-Developer A is using branch A</p>
  
  <p>-Developer B is using branch B</p>
  
  <p>-Both developers begin from the same point on the master</p>
  
  <p>-Developer A completes his task first, modifies somfile.c, and a successful merger back to the master is done.</p>
  
  <p>-Developer B wants to obtain the changes to somefile.c by merging the master into branch B.</p>
  
  <p>What I am seeing is that the changes made by developer A to somefile.c (which are now on the master) are being removed when merging the master into branch B.</p>
  
  <p>Can someone help me better understand why code is being removed?  Or point me to what I am doing wrong.</p>
  
  <p>Thanks</p>
  
  <p>Action by developer B:<br>
  git checkout master<br>
  git checkout branch B<br>
  git merge master</p>
  
  <p>edit: updated title for clarification
  edit2: updated format for better viewing</p>