code: func differentContents(path string, c *object.Commit, cs []*object.Commit) ([]*object.Commit, error) {
  	result := make([]*object.Commit, 0, len(cs))
  	h, found := blobHash(path, c)
  	if !found {
  		return nil, object.ErrFileNotFound
  	}
  	for _, cx := range cs {
  		if hx, found := blobHash(path, cx); found && h != hx {
  			result = append(result, cx)
  		}
  	}
  	return result, nil
  }
docs: // Returns an slice of the commits in "cs" that has the file "path", but with different
  // contents than what can be found in "c".