Merge branch 'nd/split-index'

An experiment to use two files (the base file and incremental
changes relative to it) to represent the index to reduce I/O cost
of rewriting a large index when only small part of the working tree
changes.

* nd/split-index: (32 commits)
  t1700: new tests for split-index mode
  t2104: make sure split index mode is off for the version test
  read-cache: force split index mode with GIT_TEST_SPLIT_INDEX
  read-tree: note about dropping split-index mode or index version
  read-tree: force split-index mode off on --index-output
  rev-parse: add --shared-index-path to get shared index path
  update-index --split-index: do not split if $GIT_DIR is read only
  update-index: new options to enable/disable split index mode
  split-index: strip pathname of on-disk replaced entries
  split-index: do not invalidate cache-tree at read time
  split-index: the reading part
  split-index: the writing part
  read-cache: mark updated entries for split index
  read-cache: save deleted entries in split index
  read-cache: mark new entries for split index
  read-cache: split-index mode
  read-cache: save index SHA-1 after reading
  entry.c: update cache_changed if refresh_cache is set in checkout_entry()
  cache-tree: mark istate->cache_changed on prime_cache_tree()
  cache-tree: mark istate->cache_changed on cache tree update
  ...

1 files changed, 4 insertions, 7 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index b5c3c5314f..8e44d7e5f3 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -267,9 +267,7 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 		active_cache_tree = cache_tree();
 
 	if (!cache_tree_fully_valid(active_cache_tree) &&
-	    cache_tree_update(active_cache_tree,
-			      (const struct cache_entry * const *)active_cache,
-			      active_nr, 0) < 0)
+	    cache_tree_update(&the_index, 0) < 0)
 		die(_("error building trees"));
 
 	result = lookup_tree(active_cache_tree->sha1);
@@ -2001,7 +1999,7 @@ int merge_recursive_generic(struct merge_options *o,
 			    const unsigned char **base_list,
 			    struct commit **result)
 {
-	int clean, index_fd;
+	int clean;
 	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 	struct commit *head_commit = get_ref(head, o->branch1);
 	struct commit *next_commit = get_ref(merge, o->branch2);
@@ -2018,12 +2016,11 @@ int merge_recursive_generic(struct merge_options *o,
 		}
 	}
 
-	index_fd = hold_locked_index(lock, 1);
+	hold_locked_index(lock, 1);
 	clean = merge_recursive(o, head_commit, next_commit, ca,
 			result);
 	if (active_cache_changed &&
-			(write_cache(index_fd, active_cache, active_nr) ||
-			 commit_locked_index(lock)))
+	    write_locked_index(&the_index, lock, COMMIT_LOCK))
 		return error(_("Unable to write index."));
 
 	return clean ? 0 : 1;