X-Git-Url: https://git.tokkee.org/?a=blobdiff_plain;f=merge-recursive.c;h=16f6a0f98b5df8fbb9bb5263d0d32afca678cbec;hb=e340d7d3fa1c5b9a6e7af2e3ee3d526064e56bea;hp=6dd6e2e5af779f2b3ad5da050776c37646b45a84;hpb=d0085ade9598942077f12f22b16978411d15188a;p=git.git

diff --git a/merge-recursive.c b/merge-recursive.c
index 6dd6e2e5a..16f6a0f98 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -3,13 +3,6 @@
  * Fredrik Kuivinen.
  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
  */
-#include <stdarg.h>
-#include <string.h>
-#include <assert.h>
-#include <sys/wait.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <time.h>
 #include "cache.h"
 #include "cache-tree.h"
 #include "commit.h"
@@ -22,6 +15,24 @@
 #include "unpack-trees.h"
 #include "path-list.h"
 #include "xdiff-interface.h"
+#include "interpolate.h"
+#include "attr.h"
+
+static int subtree_merge;
+
+static struct tree *shift_tree_object(struct tree *one, struct tree *two)
+{
+	unsigned char shifted[20];
+
+	/*
+	 * NEEDSWORK: this limits the recursion depth to hardcoded
+	 * value '2' to avoid excessive overhead.
+	 */
+	shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
+	if (!hashcmp(two->object.sha1, shifted))
+		return two;
+	return lookup_tree(shifted);
+}
 
 /*
  * A virtual commit has
@@ -74,27 +85,70 @@ struct stage_data
 	unsigned processed:1;
 };
 
+struct output_buffer
+{
+	struct output_buffer *next;
+	char *str;
+};
+
 static struct path_list current_file_set = {NULL, 0, 0, 1};
 static struct path_list current_directory_set = {NULL, 0, 0, 1};
 
-static int output_indent = 0;
+static int call_depth = 0;
+static int verbosity = 2;
+static int buffer_output = 1;
+static struct output_buffer *output_list, *output_end;
+
+static int show (int v)
+{
+	return (!call_depth && verbosity >= v) || verbosity >= 5;
+}
 
-static void output(const char *fmt, ...)
+static void output(int v, const char *fmt, ...)
 {
 	va_list args;
-	int i;
-	for (i = output_indent; i--;)
-		fputs("  ", stdout);
 	va_start(args, fmt);
-	vfprintf(stdout, fmt, args);
+	if (buffer_output && show(v)) {
+		struct output_buffer *b = xmalloc(sizeof(*b));
+		nfvasprintf(&b->str, fmt, args);
+		b->next = NULL;
+		if (output_end)
+			output_end->next = b;
+		else
+			output_list = b;
+		output_end = b;
+	} else if (show(v)) {
+		int i;
+		for (i = call_depth; i--;)
+			fputs("  ", stdout);
+		vfprintf(stdout, fmt, args);
+		fputc('\n', stdout);
+	}
 	va_end(args);
-	fputc('\n', stdout);
+}
+
+static void flush_output(void)
+{
+	struct output_buffer *b, *n;
+	for (b = output_list; b; b = n) {
+		int i;
+		for (i = call_depth; i--;)
+			fputs("  ", stdout);
+		fputs(b->str, stdout);
+		fputc('\n', stdout);
+		n = b->next;
+		free(b->str);
+		free(b);
+	}
+	output_list = NULL;
+	output_end = NULL;
 }
 
 static void output_commit_title(struct commit *commit)
 {
 	int i;
-	for (i = output_indent; i--;)
+	flush_output();
+	for (i = call_depth; i--;)
 		fputs("  ", stdout);
 	if (commit->util)
 		printf("virtual %s\n", (char *)commit->util);
@@ -117,35 +171,6 @@ static void output_commit_title(struct commit *commit)
 	}
 }
 
-static const char *current_index_file = NULL;
-static const char *original_index_file;
-static const char *temporary_index_file;
-static int cache_dirty = 0;
-
-static int flush_cache(void)
-{
-	/* flush temporary index */
-	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
-	int fd = hold_lock_file_for_update(lock, current_index_file, 1);
-	if (write_cache(fd, active_cache, active_nr) ||
-			close(fd) || commit_lock_file(lock))
-		die ("unable to write %s", current_index_file);
-	discard_cache();
-	cache_dirty = 0;
-	return 0;
-}
-
-static void setup_index(int temp)
-{
-	current_index_file = temp ? temporary_index_file: original_index_file;
-	if (cache_dirty) {
-		discard_cache();
-		cache_dirty = 0;
-	}
-	unlink(temporary_index_file);
-	discard_cache();
-}
-
 static struct cache_entry *make_cache_entry(unsigned int mode,
 		const unsigned char *sha1, const char *path, int stage, int refresh)
 {
@@ -174,12 +199,9 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 		const char *path, int stage, int refresh, int options)
 {
 	struct cache_entry *ce;
-	if (!cache_dirty)
-		read_cache_from(current_index_file);
-	cache_dirty++;
 	ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 	if (!ce)
-		return error("cache_addinfo failed: %s", strerror(cache_errno));
+		return error("addinfo_cache failed for path '%s'", path);
 	return add_cache_entry(ce, options);
 }
 
@@ -194,24 +216,10 @@ static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
  */
 static int index_only = 0;
 
-static int git_read_tree(struct tree *tree)
+static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 {
-	int rc;
-	struct object_list *trees = NULL;
-	struct unpack_trees_options opts;
-
-	if (cache_dirty)
-		die("read-tree with dirty cache");
-
-	memset(&opts, 0, sizeof(opts));
-	object_list_append(&tree->object, &trees);
-	rc = unpack_trees(trees, &opts);
-	cache_tree_free(&active_cache_tree);
-
-	if (rc == 0)
-		cache_dirty = 1;
-
-	return rc;
+	parse_tree(tree);
+	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
 static int git_merge_trees(int index_only,
@@ -220,14 +228,9 @@ static int git_merge_trees(int index_only,
 			   struct tree *merge)
 {
 	int rc;
-	struct object_list *trees = NULL;
+	struct tree_desc t[3];
 	struct unpack_trees_options opts;
 
-	if (!cache_dirty) {
-		read_cache_from(current_index_file);
-		cache_dirty = 1;
-	}
-
 	memset(&opts, 0, sizeof(opts));
 	if (index_only)
 		opts.index_only = 1;
@@ -237,45 +240,51 @@ static int git_merge_trees(int index_only,
 	opts.head_idx = 2;
 	opts.fn = threeway_merge;
 
-	object_list_append(&common->object, &trees);
-	object_list_append(&head->object, &trees);
-	object_list_append(&merge->object, &trees);
+	init_tree_desc_from_tree(t+0, common);
+	init_tree_desc_from_tree(t+1, head);
+	init_tree_desc_from_tree(t+2, merge);
 
-	rc = unpack_trees(trees, &opts);
+	rc = unpack_trees(3, t, &opts);
 	cache_tree_free(&active_cache_tree);
-
-	cache_dirty = 1;
-
 	return rc;
 }
 
+static int unmerged_index(void)
+{
+	int i;
+	for (i = 0; i < active_nr; i++) {
+		struct cache_entry *ce = active_cache[i];
+		if (ce_stage(ce))
+			return 1;
+	}
+	return 0;
+}
+
 static struct tree *git_write_tree(void)
 {
 	struct tree *result = NULL;
 
-	if (cache_dirty) {
-		unsigned i;
+	if (unmerged_index()) {
+		int i;
+		output(0, "There are unmerged index entries:");
 		for (i = 0; i < active_nr; i++) {
 			struct cache_entry *ce = active_cache[i];
 			if (ce_stage(ce))
-				return NULL;
+				output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 		}
-	} else
-		read_cache_from(current_index_file);
+		return NULL;
+	}
 
 	if (!active_cache_tree)
 		active_cache_tree = cache_tree();
 
 	if (!cache_tree_fully_valid(active_cache_tree) &&
-			cache_tree_update(active_cache_tree,
-				active_cache, active_nr, 0, 0) < 0)
+	    cache_tree_update(active_cache_tree,
+			      active_cache, active_nr, 0, 0) < 0)
 		die("error building trees");
 
 	result = lookup_tree(active_cache_tree->sha1);
 
-	flush_cache();
-	cache_dirty = 0;
-
 	return result;
 }
 
@@ -338,10 +347,7 @@ static struct path_list *get_unmerged(void)
 	int i;
 
 	unmerged->strdup_paths = 1;
-	if (!cache_dirty) {
-		read_cache_from(current_index_file);
-		cache_dirty++;
-	}
+
 	for (i = 0; i < active_nr; i++) {
 		struct path_list_item *item;
 		struct stage_data *e;
@@ -371,7 +377,7 @@ struct rename
 };
 
 /*
- * Get information of all renames which occured between 'o_tree' and
+ * Get information of all renames which occurred between 'o_tree' and
  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
  * 'b_tree') to be able to associate the correct cache entries with
  * the rename information. 'tree' is always equal to either a_tree or b_tree.
@@ -476,9 +482,6 @@ static int remove_file(int clean, const char *path, int no_wd)
 	int update_working_directory = !index_only && !no_wd;
 
 	if (update_cache) {
-		if (!cache_dirty)
-			read_cache_from(current_index_file);
-		cache_dirty++;
 		if (remove_file_from_cache(path))
 			return -1;
 	}
@@ -524,7 +527,7 @@ static int mkdir_p(const char *path, unsigned long mode)
 static void flush_buffer(int fd, const char *buf, unsigned long size)
 {
 	while (size > 0) {
-		long ret = xwrite(fd, buf, size);
+		long ret = write_in_full(fd, buf, size);
 		if (ret < 0) {
 			/* Ignore epipe */
 			if (errno == EPIPE)
@@ -538,6 +541,31 @@ static void flush_buffer(int fd, const char *buf, unsigned long size)
 	}
 }
 
+static int make_room_for_path(const char *path)
+{
+	int status;
+	const char *msg = "failed to create path '%s'%s";
+
+	status = mkdir_p(path, 0777);
+	if (status) {
+		if (status == -3) {
+			/* something else exists */
+			error(msg, path, ": perhaps a D/F conflict?");
+			return -1;
+		}
+		die(msg, path, "");
+	}
+
+	/* Successful unlink is good.. */
+	if (!unlink(path))
+		return 0;
+	/* .. and so is no existing file */
+	if (errno == ENOENT)
+		return 0;
+	/* .. but not some other error (who really cares what?) */
+	return error(msg, path, ": perhaps a D/F conflict?");
+}
+
 static void update_file_flags(const unsigned char *sha,
 			      unsigned mode,
 			      const char *path,
@@ -548,21 +576,22 @@ static void update_file_flags(const unsigned char *sha,
 		update_wd = 0;
 
 	if (update_wd) {
-		char type[20];
+		enum object_type type;
 		void *buf;
 		unsigned long size;
 
-		buf = read_sha1_file(sha, type, &size);
+		buf = read_sha1_file(sha, &type, &size);
 		if (!buf)
 			die("cannot read object %s '%s'", sha1_to_hex(sha), path);
-		if (strcmp(type, blob_type) != 0)
+		if (type != OBJ_BLOB)
 			die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 
-		if (S_ISREG(mode)) {
+		if (make_room_for_path(path) < 0) {
+			update_wd = 0;
+			goto update_index;
+		}
+		if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 			int fd;
-			if (mkdir_p(path, 0777))
-				die("failed to create path %s: %s", path, strerror(errno));
-			unlink(path);
 			if (mode & 0100)
 				mode = 0777;
 			else
@@ -577,12 +606,14 @@ static void update_file_flags(const unsigned char *sha,
 			memcpy(lnk, buf, size);
 			lnk[size] = '\0';
 			mkdir_p(path, 0777);
-			unlink(lnk);
+			unlink(path);
 			symlink(lnk, path);
+			free(lnk);
 		} else
 			die("do not know what to do with %06o %s '%s'",
 			    mode, sha1_to_hex(sha), path);
 	}
+ update_index:
 	if (update_cache)
 		add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 }
@@ -608,7 +639,7 @@ struct merge_file_info
 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 {
 	unsigned long size;
-	char type[20];
+	enum object_type type;
 
 	if (!hashcmp(sha1, null_sha1)) {
 		mm->ptr = xstrdup("");
@@ -616,12 +647,399 @@ static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 		return;
 	}
 
-	mm->ptr = read_sha1_file(sha1, type, &size);
-	if (!mm->ptr || strcmp(type, blob_type))
+	mm->ptr = read_sha1_file(sha1, &type, &size);
+	if (!mm->ptr || type != OBJ_BLOB)
 		die("unable to read blob object %s", sha1_to_hex(sha1));
 	mm->size = size;
 }
 
+/*
+ * Customizable low-level merge drivers support.
+ */
+
+struct ll_merge_driver;
+typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
+			   const char *path,
+			   mmfile_t *orig,
+			   mmfile_t *src1, const char *name1,
+			   mmfile_t *src2, const char *name2,
+			   mmbuffer_t *result);
+
+struct ll_merge_driver {
+	const char *name;
+	const char *description;
+	ll_merge_fn fn;
+	const char *recursive;
+	struct ll_merge_driver *next;
+	char *cmdline;
+};
+
+/*
+ * Built-in low-levels
+ */
+static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
+			   const char *path_unused,
+			   mmfile_t *orig,
+			   mmfile_t *src1, const char *name1,
+			   mmfile_t *src2, const char *name2,
+			   mmbuffer_t *result)
+{
+	/*
+	 * The tentative merge result is "ours" for the final round,
+	 * or common ancestor for an internal merge.  Still return
+	 * "conflicted merge" status.
+	 */
+	mmfile_t *stolen = index_only ? orig : src1;
+
+	result->ptr = stolen->ptr;
+	result->size = stolen->size;
+	stolen->ptr = NULL;
+	return 1;
+}
+
+static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
+			const char *path_unused,
+			mmfile_t *orig,
+			mmfile_t *src1, const char *name1,
+			mmfile_t *src2, const char *name2,
+			mmbuffer_t *result)
+{
+	xpparam_t xpp;
+
+	if (buffer_is_binary(orig->ptr, orig->size) ||
+	    buffer_is_binary(src1->ptr, src1->size) ||
+	    buffer_is_binary(src2->ptr, src2->size)) {
+		warning("Cannot merge binary files: %s vs. %s\n",
+			name1, name2);
+		return ll_binary_merge(drv_unused, path_unused,
+				       orig, src1, name1,
+				       src2, name2,
+				       result);
+	}
+
+	memset(&xpp, 0, sizeof(xpp));
+	return xdl_merge(orig,
+			 src1, name1,
+			 src2, name2,
+			 &xpp, XDL_MERGE_ZEALOUS,
+			 result);
+}
+
+static int ll_union_merge(const struct ll_merge_driver *drv_unused,
+			  const char *path_unused,
+			  mmfile_t *orig,
+			  mmfile_t *src1, const char *name1,
+			  mmfile_t *src2, const char *name2,
+			  mmbuffer_t *result)
+{
+	char *src, *dst;
+	long size;
+	const int marker_size = 7;
+
+	int status = ll_xdl_merge(drv_unused, path_unused,
+				  orig, src1, NULL, src2, NULL, result);
+	if (status <= 0)
+		return status;
+	size = result->size;
+	src = dst = result->ptr;
+	while (size) {
+		char ch;
+		if ((marker_size < size) &&
+		    (*src == '<' || *src == '=' || *src == '>')) {
+			int i;
+			ch = *src;
+			for (i = 0; i < marker_size; i++)
+				if (src[i] != ch)
+					goto not_a_marker;
+			if (src[marker_size] != '\n')
+				goto not_a_marker;
+			src += marker_size + 1;
+			size -= marker_size + 1;
+			continue;
+		}
+	not_a_marker:
+		do {
+			ch = *src++;
+			*dst++ = ch;
+			size--;
+		} while (ch != '\n' && size);
+	}
+	result->size = dst - result->ptr;
+	return 0;
+}
+
+#define LL_BINARY_MERGE 0
+#define LL_TEXT_MERGE 1
+#define LL_UNION_MERGE 2
+static struct ll_merge_driver ll_merge_drv[] = {
+	{ "binary", "built-in binary merge", ll_binary_merge },
+	{ "text", "built-in 3-way text merge", ll_xdl_merge },
+	{ "union", "built-in union merge", ll_union_merge },
+};
+
+static void create_temp(mmfile_t *src, char *path)
+{
+	int fd;
+
+	strcpy(path, ".merge_file_XXXXXX");
+	fd = xmkstemp(path);
+	if (write_in_full(fd, src->ptr, src->size) != src->size)
+		die("unable to write temp-file");
+	close(fd);
+}
+
+/*
+ * User defined low-level merge driver support.
+ */
+static int ll_ext_merge(const struct ll_merge_driver *fn,
+			const char *path,
+			mmfile_t *orig,
+			mmfile_t *src1, const char *name1,
+			mmfile_t *src2, const char *name2,
+			mmbuffer_t *result)
+{
+	char temp[3][50];
+	char cmdbuf[2048];
+	struct interp table[] = {
+		{ "%O" },
+		{ "%A" },
+		{ "%B" },
+	};
+	struct child_process child;
+	const char *args[20];
+	int status, fd, i;
+	struct stat st;
+
+	if (fn->cmdline == NULL)
+		die("custom merge driver %s lacks command line.", fn->name);
+
+	result->ptr = NULL;
+	result->size = 0;
+	create_temp(orig, temp[0]);
+	create_temp(src1, temp[1]);
+	create_temp(src2, temp[2]);
+
+	interp_set_entry(table, 0, temp[0]);
+	interp_set_entry(table, 1, temp[1]);
+	interp_set_entry(table, 2, temp[2]);
+
+	output(1, "merging %s using %s", path,
+	       fn->description ? fn->description : fn->name);
+
+	interpolate(cmdbuf, sizeof(cmdbuf), fn->cmdline, table, 3);
+
+	memset(&child, 0, sizeof(child));
+	child.argv = args;
+	args[0] = "sh";
+	args[1] = "-c";
+	args[2] = cmdbuf;
+	args[3] = NULL;
+
+	status = run_command(&child);
+	if (status < -ERR_RUN_COMMAND_FORK)
+		; /* failure in run-command */
+	else
+		status = -status;
+	fd = open(temp[1], O_RDONLY);
+	if (fd < 0)
+		goto bad;
+	if (fstat(fd, &st))
+		goto close_bad;
+	result->size = st.st_size;
+	result->ptr = xmalloc(result->size + 1);
+	if (read_in_full(fd, result->ptr, result->size) != result->size) {
+		free(result->ptr);
+		result->ptr = NULL;
+		result->size = 0;
+	}
+ close_bad:
+	close(fd);
+ bad:
+	for (i = 0; i < 3; i++)
+		unlink(temp[i]);
+	return status;
+}
+
+/*
+ * merge.default and merge.driver configuration items
+ */
+static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
+static const char *default_ll_merge;
+
+static int read_merge_config(const char *var, const char *value)
+{
+	struct ll_merge_driver *fn;
+	const char *ep, *name;
+	int namelen;
+
+	if (!strcmp(var, "merge.default")) {
+		if (value)
+			default_ll_merge = strdup(value);
+		return 0;
+	}
+
+	/*
+	 * We are not interested in anything but "merge.<name>.variable";
+	 * especially, we do not want to look at variables such as
+	 * "merge.summary", "merge.tool", and "merge.verbosity".
+	 */
+	if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
+		return 0;
+
+	/*
+	 * Find existing one as we might be processing merge.<name>.var2
+	 * after seeing merge.<name>.var1.
+	 */
+	name = var + 6;
+	namelen = ep - name;
+	for (fn = ll_user_merge; fn; fn = fn->next)
+		if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
+			break;
+	if (!fn) {
+		char *namebuf;
+		fn = xcalloc(1, sizeof(struct ll_merge_driver));
+		namebuf = xmalloc(namelen + 1);
+		memcpy(namebuf, name, namelen);
+		namebuf[namelen] = 0;
+		fn->name = namebuf;
+		fn->fn = ll_ext_merge;
+		fn->next = NULL;
+		*ll_user_merge_tail = fn;
+		ll_user_merge_tail = &(fn->next);
+	}
+
+	ep++;
+
+	if (!strcmp("name", ep)) {
+		if (!value)
+			return error("%s: lacks value", var);
+		fn->description = strdup(value);
+		return 0;
+	}
+
+	if (!strcmp("driver", ep)) {
+		if (!value)
+			return error("%s: lacks value", var);
+		/*
+		 * merge.<name>.driver specifies the command line:
+		 *
+		 *	command-line
+		 *
+		 * The command-line will be interpolated with the following
+		 * tokens and is given to the shell:
+		 *
+		 *    %O - temporary file name for the merge base.
+		 *    %A - temporary file name for our version.
+		 *    %B - temporary file name for the other branches' version.
+		 *
+		 * The external merge driver should write the results in the
+		 * file named by %A, and signal that it has done with zero exit
+		 * status.
+		 */
+		fn->cmdline = strdup(value);
+		return 0;
+	}
+
+	if (!strcmp("recursive", ep)) {
+		if (!value)
+			return error("%s: lacks value", var);
+		fn->recursive = strdup(value);
+		return 0;
+	}
+
+	return 0;
+}
+
+static void initialize_ll_merge(void)
+{
+	if (ll_user_merge_tail)
+		return;
+	ll_user_merge_tail = &ll_user_merge;
+	git_config(read_merge_config);
+}
+
+static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
+{
+	struct ll_merge_driver *fn;
+	const char *name;
+	int i;
+
+	initialize_ll_merge();
+
+	if (ATTR_TRUE(merge_attr))
+		return &ll_merge_drv[LL_TEXT_MERGE];
+	else if (ATTR_FALSE(merge_attr))
+		return &ll_merge_drv[LL_BINARY_MERGE];
+	else if (ATTR_UNSET(merge_attr)) {
+		if (!default_ll_merge)
+			return &ll_merge_drv[LL_TEXT_MERGE];
+		else
+			name = default_ll_merge;
+	}
+	else
+		name = merge_attr;
+
+	for (fn = ll_user_merge; fn; fn = fn->next)
+		if (!strcmp(fn->name, name))
+			return fn;
+
+	for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
+		if (!strcmp(ll_merge_drv[i].name, name))
+			return &ll_merge_drv[i];
+
+	/* default to the 3-way */
+	return &ll_merge_drv[LL_TEXT_MERGE];
+}
+
+static const char *git_path_check_merge(const char *path)
+{
+	static struct git_attr_check attr_merge_check;
+
+	if (!attr_merge_check.attr)
+		attr_merge_check.attr = git_attr("merge", 5);
+
+	if (git_checkattr(path, 1, &attr_merge_check))
+		return NULL;
+	return attr_merge_check.value;
+}
+
+static int ll_merge(mmbuffer_t *result_buf,
+		    struct diff_filespec *o,
+		    struct diff_filespec *a,
+		    struct diff_filespec *b,
+		    const char *branch1,
+		    const char *branch2)
+{
+	mmfile_t orig, src1, src2;
+	char *name1, *name2;
+	int merge_status;
+	const char *ll_driver_name;
+	const struct ll_merge_driver *driver;
+
+	name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
+	name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
+
+	fill_mm(o->sha1, &orig);
+	fill_mm(a->sha1, &src1);
+	fill_mm(b->sha1, &src2);
+
+	ll_driver_name = git_path_check_merge(a->path);
+	driver = find_ll_merge_driver(ll_driver_name);
+
+	if (index_only && driver->recursive)
+		driver = find_ll_merge_driver(driver->recursive);
+	merge_status = driver->fn(driver, a->path,
+				  &orig, &src1, name1, &src2, name2,
+				  result_buf);
+
+	free(name1);
+	free(name2);
+	free(orig.ptr);
+	free(src1.ptr);
+	free(src2.ptr);
+	return merge_status;
+}
+
 static struct merge_file_info merge_file(struct diff_filespec *o,
 		struct diff_filespec *a, struct diff_filespec *b,
 		const char *branch1, const char *branch2)
@@ -650,30 +1068,11 @@ static struct merge_file_info merge_file(struct diff_filespec *o,
 		else if (sha_eq(b->sha1, o->sha1))
 			hashcpy(result.sha, a->sha1);
 		else if (S_ISREG(a->mode)) {
-			mmfile_t orig, src1, src2;
 			mmbuffer_t result_buf;
-			xpparam_t xpp;
-			char *name1, *name2;
 			int merge_status;
 
-			name1 = xstrdup(mkpath("%s/%s", branch1, a->path));
-			name2 = xstrdup(mkpath("%s/%s", branch2, b->path));
-
-			fill_mm(o->sha1, &orig);
-			fill_mm(a->sha1, &src1);
-			fill_mm(b->sha1, &src2);
-
-			memset(&xpp, 0, sizeof(xpp));
-			merge_status = xdl_merge(&orig,
-						 &src1, name1,
-						 &src2, name2,
-						 &xpp, XDL_MERGE_ZEALOUS,
-						 &result_buf);
-			free(name1);
-			free(name2);
-			free(orig.ptr);
-			free(src1.ptr);
-			free(src2.ptr);
+			merge_status = ll_merge(&result_buf, o, a, b,
+						branch1, branch2);
 
 			if ((merge_status < 0) || !result_buf.ptr)
 				die("Failed to execute internal merge");
@@ -712,18 +1111,29 @@ static void conflict_rename_rename(struct rename *ren1,
 	const char *dst_name2 = ren2_dst;
 	if (path_list_has_path(&current_directory_set, ren1_dst)) {
 		dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
-		output("%s is a directory in %s adding as %s instead",
+		output(1, "%s is a directory in %s added as %s instead",
 		       ren1_dst, branch2, dst_name1);
 		remove_file(0, ren1_dst, 0);
 	}
 	if (path_list_has_path(&current_directory_set, ren2_dst)) {
 		dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
-		output("%s is a directory in %s adding as %s instead",
+		output(1, "%s is a directory in %s added as %s instead",
 		       ren2_dst, branch1, dst_name2);
 		remove_file(0, ren2_dst, 0);
 	}
-	update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
-	update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+	if (index_only) {
+		remove_file_from_cache(dst_name1);
+		remove_file_from_cache(dst_name2);
+		/*
+		 * Uncomment to leave the conflicting names in the resulting tree
+		 *
+		 * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
+		 * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
+		 */
+	} else {
+		update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
+		update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+	}
 	while (delp--)
 		free(del[delp]);
 }
@@ -732,7 +1142,7 @@ static void conflict_rename_dir(struct rename *ren1,
 				const char *branch1)
 {
 	char *new_path = unique_path(ren1->pair->two->path, branch1);
-	output("Renaming %s to %s instead", ren1->pair->one->path, new_path);
+	output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
 	remove_file(0, ren1->pair->two->path, 0);
 	update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 	free(new_path);
@@ -745,7 +1155,7 @@ static void conflict_rename_rename_2(struct rename *ren1,
 {
 	char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 	char *new_path2 = unique_path(ren2->pair->two->path, branch2);
-	output("Renaming %s to %s and %s to %s instead",
+	output(1, "Renamed %s to %s and %s to %s instead",
 	       ren1->pair->one->path, new_path1,
 	       ren2->pair->one->path, new_path2);
 	remove_file(0, ren1->pair->two->path, 0);
@@ -838,11 +1248,17 @@ static int process_renames(struct path_list *a_renames,
 			ren2->processed = 1;
 			if (strcmp(ren1_dst, ren2_dst) != 0) {
 				clean_merge = 0;
-				output("CONFLICT (rename/rename): "
-				       "Rename %s->%s in branch %s "
-				       "rename %s->%s in %s",
+				output(1, "CONFLICT (rename/rename): "
+				       "Rename \"%s\"->\"%s\" in branch \"%s\" "
+				       "rename \"%s\"->\"%s\" in \"%s\"%s",
 				       src, ren1_dst, branch1,
-				       src, ren2_dst, branch2);
+				       src, ren2_dst, branch2,
+				       index_only ? " (left unresolved)": "");
+				if (index_only) {
+					remove_file_from_cache(src);
+					update_file(0, ren1->pair->one->sha1,
+						    ren1->pair->one->mode, src);
+				}
 				conflict_rename_rename(ren1, branch1, ren2, branch2);
 			} else {
 				struct merge_file_info mfi;
@@ -853,13 +1269,13 @@ static int process_renames(struct path_list *a_renames,
 						 branch1,
 						 branch2);
 				if (mfi.merge || !mfi.clean)
-					output("Renaming %s->%s", src, ren1_dst);
+					output(1, "Renamed %s->%s", src, ren1_dst);
 
 				if (mfi.merge)
-					output("Auto-merging %s", ren1_dst);
+					output(2, "Auto-merged %s", ren1_dst);
 
 				if (!mfi.clean) {
-					output("CONFLICT (content): merge conflict in %s",
+					output(1, "CONFLICT (content): merge conflict in %s",
 					       ren1_dst);
 					clean_merge = 0;
 
@@ -879,7 +1295,7 @@ static int process_renames(struct path_list *a_renames,
 			struct diff_filespec src_other, dst_other;
 			int try_merge, stage = a_renames == renames1 ? 3: 2;
 
-			remove_file(1, ren1_src, index_only);
+			remove_file(1, ren1_src, index_only || stage == 3);
 
 			hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 			src_other.mode = ren1->src_entry->stages[stage].mode;
@@ -890,14 +1306,14 @@ static int process_renames(struct path_list *a_renames,
 
 			if (path_list_has_path(&current_directory_set, ren1_dst)) {
 				clean_merge = 0;
-				output("CONFLICT (rename/directory): Rename %s->%s in %s "
+				output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
 				       " directory %s added in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren1_dst, branch2);
 				conflict_rename_dir(ren1, branch1);
 			} else if (sha_eq(src_other.sha1, null_sha1)) {
 				clean_merge = 0;
-				output("CONFLICT (rename/delete): Rename %s->%s in %s "
+				output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
 				       "and deleted in %s",
 				       ren1_src, ren1_dst, branch1,
 				       branch2);
@@ -906,19 +1322,19 @@ static int process_renames(struct path_list *a_renames,
 				const char *new_path;
 				clean_merge = 0;
 				try_merge = 1;
-				output("CONFLICT (rename/add): Rename %s->%s in %s. "
+				output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
 				       "%s added in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren1_dst, branch2);
 				new_path = unique_path(ren1_dst, branch2);
-				output("Adding as %s instead", new_path);
+				output(1, "Added as %s instead", new_path);
 				update_file(0, dst_other.sha1, dst_other.mode, new_path);
 			} else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 				ren2 = item->util;
 				clean_merge = 0;
 				ren2->processed = 1;
-				output("CONFLICT (rename/rename): Rename %s->%s in %s. "
-				       "Rename %s->%s in %s",
+				output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
+				       "Renamed %s->%s in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren2->pair->one->path, ren2->pair->two->path, branch2);
 				conflict_rename_rename_2(ren1, branch1, ren2, branch2);
@@ -941,34 +1357,43 @@ static int process_renames(struct path_list *a_renames,
 				mfi = merge_file(o, a, b,
 						a_branch, b_branch);
 
-				if (mfi.merge || !mfi.clean)
-					output("Renaming %s => %s", ren1_src, ren1_dst);
-				if (mfi.merge)
-					output("Auto-merging %s", ren1_dst);
-				if (!mfi.clean) {
-					output("CONFLICT (rename/modify): Merge conflict in %s",
-					       ren1_dst);
-					clean_merge = 0;
-
-					if (!index_only)
-						update_stages(ren1_dst,
-								o, a, b, 1);
+				if (mfi.clean &&
+				    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
+				    mfi.mode == ren1->pair->two->mode)
+					/*
+					 * This messaged is part of
+					 * t6022 test. If you change
+					 * it update the test too.
+					 */
+					output(3, "Skipped %s (merged same as existing)", ren1_dst);
+				else {
+					if (mfi.merge || !mfi.clean)
+						output(1, "Renamed %s => %s", ren1_src, ren1_dst);
+					if (mfi.merge)
+						output(2, "Auto-merged %s", ren1_dst);
+					if (!mfi.clean) {
+						output(1, "CONFLICT (rename/modify): Merge conflict in %s",
+						       ren1_dst);
+						clean_merge = 0;
+
+						if (!index_only)
+							update_stages(ren1_dst,
+								      o, a, b, 1);
+					}
+					update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 				}
-				update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 			}
 		}
 	}
 	path_list_clear(&a_by_dst, 0);
 	path_list_clear(&b_by_dst, 0);
 
-	if (cache_dirty)
-		flush_cache();
 	return clean_merge;
 }
 
-static unsigned char *has_sha(const unsigned char *sha)
+static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 {
-	return is_null_sha1(sha) ? NULL: (unsigned char *)sha;
+	return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 }
 
 /* Per entry merge function */
@@ -981,12 +1406,12 @@ static int process_entry(const char *path, struct stage_data *entry,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
-	unsigned char *o_sha = has_sha(entry->stages[1].sha);
-	unsigned char *a_sha = has_sha(entry->stages[2].sha);
-	unsigned char *b_sha = has_sha(entry->stages[3].sha);
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
+	unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
+	unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
+	unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
 
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
@@ -996,20 +1421,20 @@ static int process_entry(const char *path, struct stage_data *entry,
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
-				output("Removing %s", path);
+				output(2, "Removed %s", path);
 			/* do not touch working file if it did not exist */
 			remove_file(1, path, !a_sha);
 		} else {
 			/* Deleted in one and changed in the other */
 			clean_merge = 0;
 			if (!a_sha) {
-				output("CONFLICT (delete/modify): %s deleted in %s "
+				output(1, "CONFLICT (delete/modify): %s deleted in %s "
 				       "and modified in %s. Version %s of %s left in tree.",
 				       path, branch1,
 				       branch2, branch2, path);
 				update_file(0, b_sha, b_mode, path);
 			} else {
-				output("CONFLICT (delete/modify): %s deleted in %s "
+				output(1, "CONFLICT (delete/modify): %s deleted in %s "
 				       "and modified in %s. Version %s of %s left in tree.",
 				       path, branch2,
 				       branch1, branch1, path);
@@ -1042,13 +1467,13 @@ static int process_entry(const char *path, struct stage_data *entry,
 		if (path_list_has_path(&current_directory_set, path)) {
 			const char *new_path = unique_path(path, add_branch);
 			clean_merge = 0;
-			output("CONFLICT (%s): There is a directory with name %s in %s. "
-			       "Adding %s as %s",
+			output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
+			       "Added %s as %s",
 			       conf, path, other_branch, path, new_path);
 			remove_file(0, path, 0);
 			update_file(0, sha, mode, new_path);
 		} else {
-			output("Adding %s", path);
+			output(2, "Added %s", path);
 			update_file(1, sha, mode, path);
 		}
 	} else if (a_sha && b_sha) {
@@ -1062,7 +1487,7 @@ static int process_entry(const char *path, struct stage_data *entry,
 			reason = "add/add";
 			o_sha = (unsigned char *)null_sha1;
 		}
-		output("Auto-merging %s", path);
+		output(2, "Auto-merged %s", path);
 		o.path = a.path = b.path = (char *)path;
 		hashcpy(o.sha1, o_sha);
 		o.mode = o_mode;
@@ -1078,7 +1503,7 @@ static int process_entry(const char *path, struct stage_data *entry,
 			update_file(1, mfi.sha, mfi.mode, path);
 		else {
 			clean_merge = 0;
-			output("CONFLICT (%s): Merge conflict in %s",
+			output(1, "CONFLICT (%s): Merge conflict in %s",
 					reason, path);
 
 			if (index_only)
@@ -1087,12 +1512,15 @@ static int process_entry(const char *path, struct stage_data *entry,
 				update_file_flags(mfi.sha, mfi.mode, path,
 					      0 /* update_cache */, 1 /* update_working_directory */);
 		}
+	} else if (!o_sha && !a_sha && !b_sha) {
+		/*
+		 * this entry was deleted altogether. a_mode == 0 means
+		 * we had that path and want to actively remove it.
+		 */
+		remove_file(1, path, !a_mode);
 	} else
 		die("Fatal merge failure, shouldn't happen.");
 
-	if (cache_dirty)
-		flush_cache();
-
 	return clean_merge;
 }
 
@@ -1104,8 +1532,14 @@ static int merge_trees(struct tree *head,
 		       struct tree **result)
 {
 	int code, clean;
+
+	if (subtree_merge) {
+		merge = shift_tree_object(head, merge);
+		common = shift_tree_object(head, common);
+	}
+
 	if (sha_eq(common->object.sha1, merge->object.sha1)) {
-		output("Already uptodate!");
+		output(0, "Already uptodate!");
 		*result = head;
 		return 1;
 	}
@@ -1117,9 +1551,7 @@ static int merge_trees(struct tree *head,
 		    sha1_to_hex(head->object.sha1),
 		    sha1_to_hex(merge->object.sha1));
 
-	*result = git_write_tree();
-
-	if (!*result) {
+	if (unmerged_index()) {
 		struct path_list *entries, *re_head, *re_merge;
 		int i;
 		path_list_clear(&current_file_set, 1);
@@ -1135,9 +1567,8 @@ static int merge_trees(struct tree *head,
 		for (i = 0; i < entries->nr; i++) {
 			const char *path = entries->items[i].path;
 			struct stage_data *e = entries->items[i].util;
-			if (e->processed)
-				continue;
-			if (!process_entry(path, e, branch1, branch2))
+			if (!e->processed
+				&& !process_entry(path, e, branch1, branch2))
 				clean = 0;
 		}
 
@@ -1145,17 +1576,12 @@ static int merge_trees(struct tree *head,
 		path_list_clear(re_head, 0);
 		path_list_clear(entries, 1);
 
-		if (clean || index_only)
-			*result = git_write_tree();
-		else
-			*result = NULL;
-	} else {
-		clean = 1;
-		printf("merging of trees %s and %s resulted in %s\n",
-		       sha1_to_hex(head->object.sha1),
-		       sha1_to_hex(merge->object.sha1),
-		       sha1_to_hex((*result)->object.sha1));
 	}
+	else
+		clean = 1;
+
+	if (index_only)
+		*result = git_write_tree();
 
 	return clean;
 }
@@ -1173,33 +1599,36 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
 
 /*
  * Merge the commits h1 and h2, return the resulting virtual
- * commit object and a flag indicating the cleaness of the merge.
+ * commit object and a flag indicating the cleanness of the merge.
  */
 static int merge(struct commit *h1,
 		 struct commit *h2,
 		 const char *branch1,
 		 const char *branch2,
-		 int call_depth /* =0 */,
-		 struct commit *ancestor /* =None */,
+		 struct commit_list *ca,
 		 struct commit **result)
 {
-	struct commit_list *ca = NULL, *iter;
+	struct commit_list *iter;
 	struct commit *merged_common_ancestors;
 	struct tree *mrtree;
 	int clean;
 
-	output("Merging:");
-	output_commit_title(h1);
-	output_commit_title(h2);
+	if (show(4)) {
+		output(4, "Merging:");
+		output_commit_title(h1);
+		output_commit_title(h2);
+	}
 
-	if (ancestor)
-		commit_list_insert(ancestor, &ca);
-	else
-		ca = reverse_commit_list(get_merge_bases(h1, h2, 1));
+	if (!ca) {
+		ca = get_merge_bases(h1, h2, 1);
+		ca = reverse_commit_list(ca);
+	}
 
-	output("found %u common ancestor(s):", commit_list_count(ca));
-	for (iter = ca; iter; iter = iter->next)
-		output_commit_title(iter->item);
+	if (show(5)) {
+		output(5, "found %u common ancestor(s):", commit_list_count(ca));
+		for (iter = ca; iter; iter = iter->next)
+			output_commit_title(iter->item);
+	}
 
 	merged_common_ancestors = pop_commit(&ca);
 	if (merged_common_ancestors == NULL) {
@@ -1208,53 +1637,62 @@ static int merge(struct commit *h1,
 
 		tree->object.parsed = 1;
 		tree->object.type = OBJ_TREE;
-		write_sha1_file(NULL, 0, tree_type, tree->object.sha1);
+		pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
 		merged_common_ancestors = make_virtual_commit(tree, "ancestor");
 	}
 
 	for (iter = ca; iter; iter = iter->next) {
-		output_indent = call_depth + 1;
+		call_depth++;
 		/*
 		 * When the merge fails, the result contains files
 		 * with conflict markers. The cleanness flag is
-		 * ignored, it was never acutally used, as result of
-		 * merge_trees has always overwritten it: the commited
+		 * ignored, it was never actually used, as result of
+		 * merge_trees has always overwritten it: the committed
 		 * "conflicts" were already resolved.
 		 */
+		discard_cache();
 		merge(merged_common_ancestors, iter->item,
 		      "Temporary merge branch 1",
 		      "Temporary merge branch 2",
-		      call_depth + 1,
 		      NULL,
 		      &merged_common_ancestors);
-		output_indent = call_depth;
+		call_depth--;
 
 		if (!merged_common_ancestors)
 			die("merge returned no commit");
 	}
 
-	if (call_depth == 0) {
-		setup_index(0 /* $GIT_DIR/index */);
+	discard_cache();
+	if (!call_depth) {
+		read_cache();
 		index_only = 0;
-	} else {
-		setup_index(1 /* temporary index */);
-		git_read_tree(h1->tree);
+	} else
 		index_only = 1;
-	}
 
 	clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
 			    branch1, branch2, &mrtree);
 
-	if (!ancestor && (clean || index_only)) {
+	if (index_only) {
 		*result = make_virtual_commit(mrtree, "merged tree");
 		commit_list_insert(h1, &(*result)->parents);
 		commit_list_insert(h2, &(*result)->parents->next);
-	} else
-		*result = NULL;
-
+	}
+	flush_output();
 	return clean;
 }
 
+static const char *better_branch_name(const char *branch)
+{
+	static char githead_env[8 + 40 + 1];
+	char *name;
+
+	if (strlen(branch) != 40)
+		return branch;
+	sprintf(githead_env, "GITHEAD_%s", branch);
+	name = getenv(githead_env);
+	return name ? name : branch;
+}
+
 static struct commit *get_ref(const char *ref)
 {
 	unsigned char sha1[20];
@@ -1263,6 +1701,9 @@ static struct commit *get_ref(const char *ref)
 	if (get_sha1(ref, sha1))
 		die("Could not resolve ref '%s'", ref);
 	object = deref_tag(parse_object(sha1), ref, strlen(ref));
+	if (object->type == OBJ_TREE)
+		return make_virtual_commit((struct tree*)object,
+			better_branch_name(ref));
 	if (object->type != OBJ_COMMIT)
 		return NULL;
 	if (parse_commit((struct commit *)object))
@@ -1270,21 +1711,36 @@ static struct commit *get_ref(const char *ref)
 	return (struct commit *)object;
 }
 
+static int merge_config(const char *var, const char *value)
+{
+	if (!strcasecmp(var, "merge.verbosity")) {
+		verbosity = git_config_int(var, value);
+		return 0;
+	}
+	return git_default_config(var, value);
+}
+
 int main(int argc, char *argv[])
 {
-	static const char *bases[2];
+	static const char *bases[20];
 	static unsigned bases_count = 0;
 	int i, clean;
 	const char *branch1, *branch2;
 	struct commit *result, *h1, *h2;
+	struct commit_list *ca = NULL;
+	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
+	int index_fd;
 
-	git_config(git_default_config); /* core.filemode */
-	original_index_file = getenv("GIT_INDEX_FILE");
-
-	if (!original_index_file)
-		original_index_file = xstrdup(git_path("index"));
+	if (argv[0]) {
+		int namelen = strlen(argv[0]);
+		if (8 < namelen &&
+		    !strcmp(argv[0] + namelen - 8, "-subtree"))
+			subtree_merge = 1;
+	}
 
-	temporary_index_file = xstrdup(git_path("mrg-rcrsv-tmp-idx"));
+	git_config(merge_config);
+	if (getenv("GIT_MERGE_VERBOSITY"))
+		verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
 
 	if (argc < 4)
 		die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
@@ -1297,26 +1753,33 @@ int main(int argc, char *argv[])
 	}
 	if (argc - i != 3) /* "--" "<head>" "<remote>" */
 		die("Not handling anything other than two heads merge.");
+	if (verbosity >= 5)
+		buffer_output = 0;
 
 	branch1 = argv[++i];
 	branch2 = argv[++i];
-	printf("Merging %s with %s\n", branch1, branch2);
 
 	h1 = get_ref(branch1);
 	h2 = get_ref(branch2);
 
-	if (bases_count == 1) {
-		struct commit *ancestor = get_ref(bases[0]);
-		clean = merge(h1, h2, branch1, branch2, 0, ancestor, &result);
-	} else
-		clean = merge(h1, h2, branch1, branch2, 0, NULL, &result);
+	branch1 = better_branch_name(branch1);
+	branch2 = better_branch_name(branch2);
+
+	if (show(3))
+		printf("Merging %s with %s\n", branch1, branch2);
 
-	if (cache_dirty)
-		flush_cache();
+	index_fd = hold_locked_index(lock, 1);
+
+	for (i = 0; i < bases_count; i++) {
+		struct commit *ancestor = get_ref(bases[i]);
+		ca = commit_list_insert(ancestor, &ca);
+	}
+	clean = merge(h1, h2, branch1, branch2, ca, &result);
+
+	if (active_cache_changed &&
+	    (write_cache(index_fd, active_cache, active_nr) ||
+	     close(index_fd) || commit_locked_index(lock)))
+			die ("unable to write %s", get_index_file());
 
 	return clean ? 0: 1;
 }
-
-/*
-vim: sw=8 noet
-*/