title: Why does git run "git gc --auto" on every merge?
body: <p>Today, git started acting funny (well, funnier than usual) by insisting on running <code>git gc</code> after every single merge, even if they are back to back.</p>
  
  <pre><code>C:\Projects\my-current-project&gt;git pull
  remote: Counting objects: 31, done.
  remote: Compressing objects: 100% (16/16), done.
  remote: Total 16 (delta 11), reused 0 (delta 0)
  Unpacking objects: 100% (16/16), done.
  From git.company.com:git/
     e992ce8..6376211  mybranch/next -&gt; origin/mybranch/next
  Merge made by recursive.
  Auto packing the repository for optimum performance. You may also run "git gc" manually. See "git help gc" for more information.
  FIND: Parameter format not correct
  Counting objects: 252732, done.
  Delta compression using up to 2 threads.
  Compressing objects: 100% (59791/59791), done.
  Writing objects: 100% (252732/252732), done.
  Total 252732 (delta 190251), reused 252678 (delta 190222)
  Removing duplicate objects: 100% (256/256), done.
   .../stylesheets/style.css                          |    2 +-
   1 files changed, 1 insertions(+), 1 deletions(-)
  </code></pre>
  
  <p>This is incredibly disruptive, and I fear that it means that my repository is corrupt somehow (this is the first time I've ever seen it automatically <code>gc</code>). Are my fears unfounded? If my repository is OK, how do I make the auto-packing stop?!</p>