Merge branch 'tr/cache-tree'

* tr/cache-tree:
  reset: update cache-tree data when appropriate
  commit: write cache-tree data when writing index anyway
  Refactor cache_tree_update idiom from commit
  Test the current state of the cache-tree optimization
  Add test-scrap-cache-tree

merge-recursive.c

@@ -264,7 +264,7 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 
 	if (!cache_tree_fully_valid(active_cache_tree) &&
 	    cache_tree_update(active_cache_tree,
-			      active_cache, active_nr, 0, 0) < 0)
+			      active_cache, active_nr, 0, 0, 0) < 0)
 		die("error building trees");
 
 	result = lookup_tree(active_cache_tree->sha1);