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	/*
	* Recursive Merge algorithm stolen from git-merge-recursive.py by
	* Fredrik Kuivinen.
	* The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
	*/
	#include "cache.h"
	#include "merge-recursive.h"

	#include "advice.h"
	#include "alloc.h"
	#include "attr.h"
	#include "blob.h"
	#include "builtin.h"
	#include "cache-tree.h"
	#include "commit.h"
	#include "commit-reach.h"
	#include "config.h"
	#include "diff.h"
	#include "diffcore.h"
	#include "dir.h"
	#include "ll-merge.h"
	#include "lockfile.h"
	#include "object-store.h"
	#include "repository.h"
	#include "revision.h"
	#include "string-list.h"
	#include "submodule.h"
	#include "tag.h"
	#include "tree-walk.h"
	#include "unpack-trees.h"
	#include "xdiff-interface.h"

	struct merge_options_internal {
	int call_depth;
	int needed_rename_limit;
	struct hashmap current_file_dir_set;
	struct string_list df_conflict_file_set;
	struct unpack_trees_options unpack_opts;
	struct index_state orig_index;
	};

	struct path_hashmap_entry {
	struct hashmap_entry e;
	char path[FLEX_ARRAY];
	};

	static int path_hashmap_cmp(const void *cmp_data,
	const struct hashmap_entry *eptr,
	const struct hashmap_entry *entry_or_key,
	const void *keydata)
	{
	const struct path_hashmap_entry a, b;
	const char *key = keydata;

	a = container_of(eptr, const struct path_hashmap_entry, e);
	b = container_of(entry_or_key, const struct path_hashmap_entry, e);

	if (ignore_case)
	return strcasecmp(a->path, key ? key : b->path);
	else
	return strcmp(a->path, key ? key : b->path);
	}

	static unsigned int path_hash(const char *path)
	{
	return ignore_case ? strihash(path) : strhash(path);
	}

	/*
	* For dir_rename_entry, directory names are stored as a full path from the
	* toplevel of the repository and do not include a trailing '/'. Also:
	*
	* dir: original name of directory being renamed
	* non_unique_new_dir: if true, could not determine new_dir
	* new_dir: final name of directory being renamed
	* possible_new_dirs: temporary used to help determine new_dir; see comments
	* in get_directory_renames() for details
	*/
	struct dir_rename_entry {
	struct hashmap_entry ent;
	char *dir;
	unsigned non_unique_new_dir:1;
	struct strbuf new_dir;
	struct string_list possible_new_dirs;
	};

	static struct dir_rename_entry dir_rename_find_entry(struct hashmap hashmap,
	char *dir)
	{
	struct dir_rename_entry key;

	if (dir == NULL)
	return NULL;
	hashmap_entry_init(&key.ent, strhash(dir));
	key.dir = dir;
	return hashmap_get_entry(hashmap, &key, ent, NULL);
	}

	static int dir_rename_cmp(const void *unused_cmp_data,
	const struct hashmap_entry *eptr,
	const struct hashmap_entry *entry_or_key,
	const void *unused_keydata)
	{
	const struct dir_rename_entry e1, e2;

	e1 = container_of(eptr, const struct dir_rename_entry, ent);
	e2 = container_of(entry_or_key, const struct dir_rename_entry, ent);

	return strcmp(e1->dir, e2->dir);
	}

	static void dir_rename_init(struct hashmap *map)
	{
	hashmap_init(map, dir_rename_cmp, NULL, 0);
	}

	static void dir_rename_entry_init(struct dir_rename_entry *entry,
	char *directory)
	{
	hashmap_entry_init(&entry->ent, strhash(directory));
	entry->dir = directory;
	entry->non_unique_new_dir = 0;
	strbuf_init(&entry->new_dir, 0);
	string_list_init(&entry->possible_new_dirs, 0);
	}

	struct collision_entry {
	struct hashmap_entry ent;
	char *target_file;
	struct string_list source_files;
	unsigned reported_already:1;
	};

	static struct collision_entry collision_find_entry(struct hashmap hashmap,
	char *target_file)
	{
	struct collision_entry key;

	hashmap_entry_init(&key.ent, strhash(target_file));
	key.target_file = target_file;
	return hashmap_get_entry(hashmap, &key, ent, NULL);
	}

	static int collision_cmp(const void *unused_cmp_data,
	const struct hashmap_entry *eptr,
	const struct hashmap_entry *entry_or_key,
	const void *unused_keydata)
	{
	const struct collision_entry e1, e2;

	e1 = container_of(eptr, const struct collision_entry, ent);
	e2 = container_of(entry_or_key, const struct collision_entry, ent);

	return strcmp(e1->target_file, e2->target_file);
	}

	static void collision_init(struct hashmap *map)
	{
	hashmap_init(map, collision_cmp, NULL, 0);
	}

	static void flush_output(struct merge_options *opt)
	{
	if (opt->buffer_output < 2 && opt->obuf.len) {
	fputs(opt->obuf.buf, stdout);
	strbuf_reset(&opt->obuf);
	}
	}

	static int err(struct merge_options opt, const char err, ...)
	{
	va_list params;

	if (opt->buffer_output < 2)
	flush_output(opt);
	else {
	strbuf_complete(&opt->obuf, '\n');
	strbuf_addstr(&opt->obuf, "error: ");
	}
	va_start(params, err);
	strbuf_vaddf(&opt->obuf, err, params);
	va_end(params);
	if (opt->buffer_output > 1)
	strbuf_addch(&opt->obuf, '\n');
	else {
	error("%s", opt->obuf.buf);
	strbuf_reset(&opt->obuf);
	}

	return -1;
	}

	static struct tree shift_tree_object(struct repository repo,
	struct tree one, struct tree two,
	const char *subtree_shift)
	{
	struct object_id shifted;

	if (!*subtree_shift) {
	shift_tree(repo, &one->object.oid, &two->object.oid, &shifted, 0);
	} else {
	shift_tree_by(repo, &one->object.oid, &two->object.oid, &shifted,
	subtree_shift);
	}
	if (oideq(&two->object.oid, &shifted))
	return two;
	return lookup_tree(repo, &shifted);
	}

	static inline void set_commit_tree(struct commit c, struct tree t)
	{
	c->maybe_tree = t;
	}

	static struct commit make_virtual_commit(struct repository repo,
	struct tree *tree,
	const char *comment)
	{
	struct commit *commit = alloc_commit_node(repo);

	set_merge_remote_desc(commit, comment, (struct object *)commit);
	set_commit_tree(commit, tree);
	commit->object.parsed = 1;
	return commit;
	}

	enum rename_type {
	RENAME_NORMAL = 0,
	RENAME_VIA_DIR,
	RENAME_ADD,
	RENAME_DELETE,
	RENAME_ONE_FILE_TO_ONE,
	RENAME_ONE_FILE_TO_TWO,
	RENAME_TWO_FILES_TO_ONE
	};

	/*
	* Since we want to write the index eventually, we cannot reuse the index
	* for these (temporary) data.
	*/
	struct stage_data {
	struct diff_filespec stages[4]; /* mostly for oid & mode; maybe path */
	struct rename_conflict_info *rename_conflict_info;
	unsigned processed:1;
	};

	struct rename {
	unsigned processed:1;
	struct diff_filepair *pair;
	const char branch; / branch that the rename occurred on */
	/*
	* If directory rename detection affected this rename, what was its
	* original type ('A' or 'R') and it's original destination before
	* the directory rename (otherwise, '\0' and NULL for these two vars).
	*/
	char dir_rename_original_type;
	char *dir_rename_original_dest;
	/*
	* Purpose of src_entry and dst_entry:
	*
	* If 'before' is renamed to 'after' then src_entry will contain
	* the versions of 'before' from the merge_base, HEAD, and MERGE in
	* stages 1, 2, and 3; dst_entry will contain the respective
	* versions of 'after' in corresponding locations. Thus, we have a
	* total of six modes and oids, though some will be null. (Stage 0
	* is ignored; we're interested in handling conflicts.)
	*
	* Since we don't turn on break-rewrites by default, neither
	* src_entry nor dst_entry can have all three of their stages have
	* non-null oids, meaning at most four of the six will be non-null.
	* Also, since this is a rename, both src_entry and dst_entry will
	* have at least one non-null oid, meaning at least two will be
	* non-null. Of the six oids, a typical rename will have three be
	* non-null. Only two implies a rename/delete, and four implies a
	* rename/add.
	*/
	struct stage_data *src_entry;
	struct stage_data *dst_entry;
	};

	struct rename_conflict_info {
	enum rename_type rename_type;
	struct rename *ren1;
	struct rename *ren2;
	};

	static inline void setup_rename_conflict_info(enum rename_type rename_type,
	struct merge_options *opt,
	struct rename *ren1,
	struct rename *ren2)
	{
	struct rename_conflict_info *ci;

	/*
	* When we have two renames involved, it's easiest to get the
	* correct things into stage 2 and 3, and to make sure that the
	* content merge puts HEAD before the other branch if we just
	* ensure that branch1 == opt->branch1. So, simply flip arguments
	* around if we don't have that.
	*/
	if (ren2 && ren1->branch != opt->branch1) {
	setup_rename_conflict_info(rename_type, opt, ren2, ren1);
	return;
	}

	CALLOC_ARRAY(ci, 1);
	ci->rename_type = rename_type;
	ci->ren1 = ren1;
	ci->ren2 = ren2;

	ci->ren1->dst_entry->processed = 0;
	ci->ren1->dst_entry->rename_conflict_info = ci;
	if (ren2) {
	ci->ren2->dst_entry->rename_conflict_info = ci;
	}
	}

	static int show(struct merge_options *opt, int v)
	{
	return (!opt->priv->call_depth && opt->verbosity >= v) \|\|
	opt->verbosity >= 5;
	}

	__attribute__((format (printf, 3, 4)))
	static void output(struct merge_options opt, int v, const char fmt, ...)
	{
	va_list ap;

	if (!show(opt, v))
	return;

	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);

	va_start(ap, fmt);
	strbuf_vaddf(&opt->obuf, fmt, ap);
	va_end(ap);

	strbuf_addch(&opt->obuf, '\n');
	if (!opt->buffer_output)
	flush_output(opt);
	}

	static void output_commit_title(struct merge_options opt, struct commit commit)
	{
	struct merge_remote_desc *desc;

	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);
	desc = merge_remote_util(commit);
	if (desc)
	strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
	else {
	strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
	DEFAULT_ABBREV);
	strbuf_addch(&opt->obuf, ' ');
	if (parse_commit(commit) != 0)
	strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
	else {
	const char *title;
	const char *msg = get_commit_buffer(commit, NULL);
	int len = find_commit_subject(msg, &title);
	if (len)
	strbuf_addf(&opt->obuf, "%.*s\n", len, title);
	unuse_commit_buffer(commit, msg);
	}
	}
	flush_output(opt);
	}

	static int add_cacheinfo(struct merge_options *opt,
	const struct diff_filespec *blob,
	const char *path, int stage, int refresh, int options)
	{
	struct index_state *istate = opt->repo->index;
	struct cache_entry *ce;
	int ret;

	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
	if (!ce)
	return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);

	ret = add_index_entry(istate, ce, options);
	if (refresh) {
	struct cache_entry *nce;

	nce = refresh_cache_entry(istate, ce,
	CE_MATCH_REFRESH \| CE_MATCH_IGNORE_MISSING);
	if (!nce)
	return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
	if (nce != ce)
	ret = add_index_entry(istate, nce, options);
	}
	return ret;
	}

	static inline int merge_detect_rename(struct merge_options *opt)
	{
	return (opt->detect_renames >= 0) ? opt->detect_renames : 1;
	}

	static void init_tree_desc_from_tree(struct tree_desc desc, struct tree tree)
	{
	parse_tree(tree);
	init_tree_desc(desc, tree->buffer, tree->size);
	}

	static int unpack_trees_start(struct merge_options *opt,
	struct tree *common,
	struct tree *head,
	struct tree *merge)
	{
	int rc;
	struct tree_desc t[3];
	struct index_state tmp_index = { NULL };

	memset(&opt->priv->unpack_opts, 0, sizeof(opt->priv->unpack_opts));
	if (opt->priv->call_depth)
	opt->priv->unpack_opts.index_only = 1;
	else
	opt->priv->unpack_opts.update = 1;
	opt->priv->unpack_opts.merge = 1;
	opt->priv->unpack_opts.head_idx = 2;
	opt->priv->unpack_opts.fn = threeway_merge;
	opt->priv->unpack_opts.src_index = opt->repo->index;
	opt->priv->unpack_opts.dst_index = &tmp_index;
	opt->priv->unpack_opts.aggressive = !merge_detect_rename(opt);
	setup_unpack_trees_porcelain(&opt->priv->unpack_opts, "merge");

	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(3, t, &opt->priv->unpack_opts);
	cache_tree_free(&opt->repo->index->cache_tree);

	/*
	* Update opt->repo->index to match the new results, AFTER saving a
	* copy in opt->priv->orig_index. Update src_index to point to the
	* saved copy. (verify_uptodate() checks src_index, and the original
	* index is the one that had the necessary modification timestamps.)
	*/
	opt->priv->orig_index = *opt->repo->index;
	*opt->repo->index = tmp_index;
	opt->priv->unpack_opts.src_index = &opt->priv->orig_index;

	return rc;
	}

	static void unpack_trees_finish(struct merge_options *opt)
	{
	discard_index(&opt->priv->orig_index);
	clear_unpack_trees_porcelain(&opt->priv->unpack_opts);
	}

	static int save_files_dirs(const struct object_id *oid,
	struct strbuf base, const char path,
	unsigned int mode, void *context)
	{
	struct path_hashmap_entry *entry;
	int baselen = base->len;
	struct merge_options *opt = context;

	strbuf_addstr(base, path);

	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
	hashmap_entry_init(&entry->e, path_hash(entry->path));
	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);

	strbuf_setlen(base, baselen);
	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
	}

	static void get_files_dirs(struct merge_options opt, struct tree tree)
	{
	struct pathspec match_all;
	memset(&match_all, 0, sizeof(match_all));
	read_tree(opt->repo, tree,
	&match_all, save_files_dirs, opt);
	}

	static int get_tree_entry_if_blob(struct repository *r,
	const struct object_id *tree,
	const char *path,
	struct diff_filespec *dfs)
	{
	int ret;

	ret = get_tree_entry(r, tree, path, &dfs->oid, &dfs->mode);
	if (S_ISDIR(dfs->mode)) {
	oidcpy(&dfs->oid, &null_oid);
	dfs->mode = 0;
	}
	return ret;
	}

	/*
	* Returns an index_entry instance which doesn't have to correspond to
	* a real cache entry in Git's index.
	*/
	static struct stage_data insert_stage_data(struct repository r,
	const char *path,
	struct tree o, struct tree a, struct tree *b,
	struct string_list *entries)
	{
	struct string_list_item *item;
	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
	get_tree_entry_if_blob(r, &o->object.oid, path, &e->stages[1]);
	get_tree_entry_if_blob(r, &a->object.oid, path, &e->stages[2]);
	get_tree_entry_if_blob(r, &b->object.oid, path, &e->stages[3]);
	item = string_list_insert(entries, path);
	item->util = e;
	return e;
	}

	/*
	* Create a dictionary mapping file names to stage_data objects. The
	* dictionary contains one entry for every path with a non-zero stage entry.
	*/
	static struct string_list get_unmerged(struct index_state istate)
	{
	struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
	int i;

	unmerged->strdup_strings = 1;

	/* TODO: audit for interaction with sparse-index. */
	ensure_full_index(istate);
	for (i = 0; i < istate->cache_nr; i++) {
	struct string_list_item *item;
	struct stage_data *e;
	const struct cache_entry *ce = istate->cache[i];
	if (!ce_stage(ce))
	continue;

	item = string_list_lookup(unmerged, ce->name);
	if (!item) {
	item = string_list_insert(unmerged, ce->name);
	item->util = xcalloc(1, sizeof(struct stage_data));
	}
	e = item->util;
	e->stages[ce_stage(ce)].mode = ce->ce_mode;
	oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
	}

	return unmerged;
	}

	static int string_list_df_name_compare(const char one, const char two)
	{
	int onelen = strlen(one);
	int twolen = strlen(two);
	/*
	* Here we only care that entries for D/F conflicts are
	* adjacent, in particular with the file of the D/F conflict
	* appearing before files below the corresponding directory.
	* The order of the rest of the list is irrelevant for us.
	*
	* To achieve this, we sort with df_name_compare and provide
	* the mode S_IFDIR so that D/F conflicts will sort correctly.
	* We use the mode S_IFDIR for everything else for simplicity,
	* since in other cases any changes in their order due to
	* sorting cause no problems for us.
	*/
	int cmp = df_name_compare(one, onelen, S_IFDIR,
	two, twolen, S_IFDIR);
	/*
	* Now that 'foo' and 'foo/bar' compare equal, we have to make sure
	* that 'foo' comes before 'foo/bar'.
	*/
	if (cmp)
	return cmp;
	return onelen - twolen;
	}

	static void record_df_conflict_files(struct merge_options *opt,
	struct string_list *entries)
	{
	/* If there is a D/F conflict and the file for such a conflict
	* currently exists in the working tree, we want to allow it to be
	* removed to make room for the corresponding directory if needed.
	* The files underneath the directories of such D/F conflicts will
	* be processed before the corresponding file involved in the D/F
	* conflict. If the D/F directory ends up being removed by the
	* merge, then we won't have to touch the D/F file. If the D/F
	* directory needs to be written to the working copy, then the D/F
	* file will simply be removed (in make_room_for_path()) to make
	* room for the necessary paths. Note that if both the directory
	* and the file need to be present, then the D/F file will be
	* reinstated with a new unique name at the time it is processed.
	*/
	struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
	const char *last_file = NULL;
	int last_len = 0;
	int i;

	/*
	* If we're merging merge-bases, we don't want to bother with
	* any working directory changes.
	*/
	if (opt->priv->call_depth)
	return;

	/* Ensure D/F conflicts are adjacent in the entries list. */
	for (i = 0; i < entries->nr; i++) {
	struct string_list_item *next = &entries->items[i];
	string_list_append(&df_sorted_entries, next->string)->util =
	next->util;
	}
	df_sorted_entries.cmp = string_list_df_name_compare;
	string_list_sort(&df_sorted_entries);

	string_list_clear(&opt->priv->df_conflict_file_set, 1);
	for (i = 0; i < df_sorted_entries.nr; i++) {
	const char *path = df_sorted_entries.items[i].string;
	int len = strlen(path);
	struct stage_data *e = df_sorted_entries.items[i].util;

	/*
	* Check if last_file & path correspond to a D/F conflict;
	* i.e. whether path is last_file+'/'+<something>.
	* If so, record that it's okay to remove last_file to make
	* room for path and friends if needed.
	*/
	if (last_file &&
	len > last_len &&
	memcmp(path, last_file, last_len) == 0 &&
	path[last_len] == '/') {
	string_list_insert(&opt->priv->df_conflict_file_set, last_file);
	}

	/*
	* Determine whether path could exist as a file in the
	* working directory as a possible D/F conflict. This
	* will only occur when it exists in stage 2 as a
	* file.
	*/
	if (S_ISREG(e->stages[2].mode) \|\| S_ISLNK(e->stages[2].mode)) {
	last_file = path;
	last_len = len;
	} else {
	last_file = NULL;
	}
	}
	string_list_clear(&df_sorted_entries, 0);
	}

	static int update_stages(struct merge_options opt, const char path,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b)
	{

	/*
	* NOTE: It is usually a bad idea to call update_stages on a path
	* before calling update_file on that same path, since it can
	* sometimes lead to spurious "refusing to lose untracked file..."
	* messages from update_file (via make_room_for path via
	* would_lose_untracked). Instead, reverse the order of the calls
	* (executing update_file first and then update_stages).
	*/
	int clear = 1;
	int options = ADD_CACHE_OK_TO_ADD \| ADD_CACHE_SKIP_DFCHECK;
	if (clear)
	if (remove_file_from_index(opt->repo->index, path))
	return -1;
	if (o)
	if (add_cacheinfo(opt, o, path, 1, 0, options))
	return -1;
	if (a)
	if (add_cacheinfo(opt, a, path, 2, 0, options))
	return -1;
	if (b)
	if (add_cacheinfo(opt, b, path, 3, 0, options))
	return -1;
	return 0;
	}

	static void update_entry(struct stage_data *entry,
	struct diff_filespec *o,
	struct diff_filespec *a,
	struct diff_filespec *b)
	{
	entry->processed = 0;
	entry->stages[1].mode = o->mode;
	entry->stages[2].mode = a->mode;
	entry->stages[3].mode = b->mode;
	oidcpy(&entry->stages[1].oid, &o->oid);
	oidcpy(&entry->stages[2].oid, &a->oid);
	oidcpy(&entry->stages[3].oid, &b->oid);
	}

	static int remove_file(struct merge_options *opt, int clean,
	const char *path, int no_wd)
	{
	int update_cache = opt->priv->call_depth \|\| clean;
	int update_working_directory = !opt->priv->call_depth && !no_wd;

	if (update_cache) {
	if (remove_file_from_index(opt->repo->index, path))
	return -1;
	}
	if (update_working_directory) {
	if (ignore_case) {
	struct cache_entry *ce;
	ce = index_file_exists(opt->repo->index, path, strlen(path),
	ignore_case);
	if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
	return 0;
	}
	if (remove_path(path))
	return -1;
	}
	return 0;
	}

	/* add a string to a strbuf, but converting "/" to "_" */
	static void add_flattened_path(struct strbuf out, const char s)
	{
	size_t i = out->len;
	strbuf_addstr(out, s);
	for (; i < out->len; i++)
	if (out->buf[i] == '/')
	out->buf[i] = '_';
	}

	static char unique_path(struct merge_options opt,
	const char *path,
	const char *branch)
	{
	struct path_hashmap_entry *entry;
	struct strbuf newpath = STRBUF_INIT;
	int suffix = 0;
	size_t base_len;

	strbuf_addf(&newpath, "%s~", path);
	add_flattened_path(&newpath, branch);

	base_len = newpath.len;
	while (hashmap_get_from_hash(&opt->priv->current_file_dir_set,
	path_hash(newpath.buf), newpath.buf) \|\|
	(!opt->priv->call_depth && file_exists(newpath.buf))) {
	strbuf_setlen(&newpath, base_len);
	strbuf_addf(&newpath, "_%d", suffix++);
	}

	FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
	hashmap_entry_init(&entry->e, path_hash(entry->path));
	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
	return strbuf_detach(&newpath, NULL);
	}

	/**
	* Check whether a directory in the index is in the way of an incoming
	* file. Return 1 if so. If check_working_copy is non-zero, also
	* check the working directory. If empty_ok is non-zero, also return
	* 0 in the case where the working-tree dir exists but is empty.
	*/
	static int dir_in_way(struct index_state istate, const char path,
	int check_working_copy, int empty_ok)
	{
	int pos;
	struct strbuf dirpath = STRBUF_INIT;
	struct stat st;

	strbuf_addstr(&dirpath, path);
	strbuf_addch(&dirpath, '/');

	pos = index_name_pos(istate, dirpath.buf, dirpath.len);

	if (pos < 0)
	pos = -1 - pos;
	if (pos < istate->cache_nr &&
	!strncmp(dirpath.buf, istate->cache[pos]->name, dirpath.len)) {
	strbuf_release(&dirpath);
	return 1;
	}

	strbuf_release(&dirpath);
	return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
	!(empty_ok && is_empty_dir(path)) &&
	!has_symlink_leading_path(path, strlen(path));
	}

	/*
	* Returns whether path was tracked in the index before the merge started,
	* and its oid and mode match the specified values
	*/
	static int was_tracked_and_matches(struct merge_options opt, const char path,
	const struct diff_filespec *blob)
	{
	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
	struct cache_entry *ce;

	if (0 > pos)
	/* we were not tracking this path before the merge */
	return 0;

	/* See if the file we were tracking before matches */
	ce = opt->priv->orig_index.cache[pos];
	return (oideq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
	}

	/*
	* Returns whether path was tracked in the index before the merge started
	*/
	static int was_tracked(struct merge_options opt, const char path)
	{
	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));

	if (0 <= pos)
	/* we were tracking this path before the merge */
	return 1;

	return 0;
	}

	static int would_lose_untracked(struct merge_options opt, const char path)
	{
	struct index_state *istate = opt->repo->index;

	/*
	* This may look like it can be simplified to:
	* return !was_tracked(opt, path) && file_exists(path)
	* but it can't. This function needs to know whether path was in
	* the working tree due to EITHER having been tracked in the index
	* before the merge OR having been put into the working copy and
	* index by unpack_trees(). Due to that either-or requirement, we
	* check the current index instead of the original one.
	*
	* Note that we do not need to worry about merge-recursive itself
	* updating the index after unpack_trees() and before calling this
	* function, because we strictly require all code paths in
	* merge-recursive to update the working tree first and the index
	* second. Doing otherwise would break
	* update_file()/would_lose_untracked(); see every comment in this
	* file which mentions "update_stages".
	*/
	int pos = index_name_pos(istate, path, strlen(path));

	if (pos < 0)
	pos = -1 - pos;
	while (pos < istate->cache_nr &&
	!strcmp(path, istate->cache[pos]->name)) {
	/*
	* If stage #0, it is definitely tracked.
	* If it has stage #2 then it was tracked
	* before this merge started. All other
	* cases the path was not tracked.
	*/
	switch (ce_stage(istate->cache[pos])) {
	case 0:
	case 2:
	return 0;
	}
	pos++;
	}
	return file_exists(path);
	}

	static int was_dirty(struct merge_options opt, const char path)
	{
	struct cache_entry *ce;
	int dirty = 1;

	if (opt->priv->call_depth \|\| !was_tracked(opt, path))
	return !dirty;

	ce = index_file_exists(opt->priv->unpack_opts.src_index,
	path, strlen(path), ignore_case);
	dirty = verify_uptodate(ce, &opt->priv->unpack_opts) != 0;
	return dirty;
	}

	static int make_room_for_path(struct merge_options opt, const char path)
	{
	int status, i;
	const char *msg = _("failed to create path '%s'%s");

	/* Unlink any D/F conflict files that are in the way */
	for (i = 0; i < opt->priv->df_conflict_file_set.nr; i++) {
	const char *df_path = opt->priv->df_conflict_file_set.items[i].string;
	size_t pathlen = strlen(path);
	size_t df_pathlen = strlen(df_path);
	if (df_pathlen < pathlen &&
	path[df_pathlen] == '/' &&
	strncmp(path, df_path, df_pathlen) == 0) {
	output(opt, 3,
	_("Removing %s to make room for subdirectory\n"),
	df_path);
	unlink(df_path);
	unsorted_string_list_delete_item(&opt->priv->df_conflict_file_set,
	i, 0);
	break;
	}
	}

	/* Make sure leading directories are created */
	status = safe_create_leading_directories_const(path);
	if (status) {
	if (status == SCLD_EXISTS)
	/* something else exists */
	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
	return err(opt, msg, path, "");
	}

	/*
	* Do not unlink a file in the work tree if we are not
	* tracking it.
	*/
	if (would_lose_untracked(opt, path))
	return err(opt, _("refusing to lose untracked file at '%s'"),
	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 err(opt, msg, path, _(": perhaps a D/F conflict?"));
	}

	static int update_file_flags(struct merge_options *opt,
	const struct diff_filespec *contents,
	const char *path,
	int update_cache,
	int update_wd)
	{
	int ret = 0;

	if (opt->priv->call_depth)
	update_wd = 0;

	if (update_wd) {
	enum object_type type;
	void *buf;
	unsigned long size;

	if (S_ISGITLINK(contents->mode)) {
	/*
	* We may later decide to recursively descend into
	* the submodule directory and update its index
	* and/or work tree, but we do not do that now.
	*/
	update_wd = 0;
	goto update_index;
	}

	buf = read_object_file(&contents->oid, &type, &size);
	if (!buf) {
	ret = err(opt, _("cannot read object %s '%s'"),
	oid_to_hex(&contents->oid), path);
	goto free_buf;
	}
	if (type != OBJ_BLOB) {
	ret = err(opt, _("blob expected for %s '%s'"),
	oid_to_hex(&contents->oid), path);
	goto free_buf;
	}
	if (S_ISREG(contents->mode)) {
	struct strbuf strbuf = STRBUF_INIT;
	if (convert_to_working_tree(opt->repo->index,
	path, buf, size, &strbuf, NULL)) {
	free(buf);
	size = strbuf.len;
	buf = strbuf_detach(&strbuf, NULL);
	}
	}

	if (make_room_for_path(opt, path) < 0) {
	update_wd = 0;
	goto free_buf;
	}
	if (S_ISREG(contents->mode) \|\|
	(!has_symlinks && S_ISLNK(contents->mode))) {
	int fd;
	int mode = (contents->mode & 0100 ? 0777 : 0666);

	fd = open(path, O_WRONLY \| O_TRUNC \| O_CREAT, mode);
	if (fd < 0) {
	ret = err(opt, _("failed to open '%s': %s"),
	path, strerror(errno));
	goto free_buf;
	}
	write_in_full(fd, buf, size);
	close(fd);
	} else if (S_ISLNK(contents->mode)) {
	char *lnk = xmemdupz(buf, size);
	safe_create_leading_directories_const(path);
	unlink(path);
	if (symlink(lnk, path))
	ret = err(opt, _("failed to symlink '%s': %s"),
	path, strerror(errno));
	free(lnk);
	} else
	ret = err(opt,
	_("do not know what to do with %06o %s '%s'"),
	contents->mode, oid_to_hex(&contents->oid), path);
	free_buf:
	free(buf);
	}
	update_index:
	if (!ret && update_cache) {
	int refresh = (!opt->priv->call_depth &&
	contents->mode != S_IFGITLINK);
	if (add_cacheinfo(opt, contents, path, 0, refresh,
	ADD_CACHE_OK_TO_ADD))
	return -1;
	}
	return ret;
	}

	static int update_file(struct merge_options *opt,
	int clean,
	const struct diff_filespec *contents,
	const char *path)
	{
	return update_file_flags(opt, contents, path,
	opt->priv->call_depth \|\| clean, !opt->priv->call_depth);
	}

	/* Low level file merging, update and removal */

	struct merge_file_info {
	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
	unsigned clean:1,
	merge:1;
	};

	static int merge_3way(struct merge_options *opt,
	mmbuffer_t *result_buf,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b,
	const char *branch1,
	const char *branch2,
	const int extra_marker_size)
	{
	mmfile_t orig, src1, src2;
	struct ll_merge_options ll_opts = {0};
	char base, name1, *name2;
	int merge_status;

	ll_opts.renormalize = opt->renormalize;
	ll_opts.extra_marker_size = extra_marker_size;
	ll_opts.xdl_opts = opt->xdl_opts;

	if (opt->priv->call_depth) {
	ll_opts.virtual_ancestor = 1;
	ll_opts.variant = 0;
	} else {
	switch (opt->recursive_variant) {
	case MERGE_VARIANT_OURS:
	ll_opts.variant = XDL_MERGE_FAVOR_OURS;
	break;
	case MERGE_VARIANT_THEIRS:
	ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
	break;
	default:
	ll_opts.variant = 0;
	break;
	}
	}

	assert(a->path && b->path && o->path && opt->ancestor);
	if (strcmp(a->path, b->path) \|\| strcmp(a->path, o->path) != 0) {
	base = mkpathdup("%s:%s", opt->ancestor, o->path);
	name1 = mkpathdup("%s:%s", branch1, a->path);
	name2 = mkpathdup("%s:%s", branch2, b->path);
	} else {
	base = mkpathdup("%s", opt->ancestor);
	name1 = mkpathdup("%s", branch1);
	name2 = mkpathdup("%s", branch2);
	}

	read_mmblob(&orig, &o->oid);
	read_mmblob(&src1, &a->oid);
	read_mmblob(&src2, &b->oid);

	/*
	* FIXME: Using a->path for normalization rules in ll_merge could be
	* wrong if we renamed from a->path to b->path. We should use the
	* target path for where the file will be written.
	*/
	merge_status = ll_merge(result_buf, a->path, &orig, base,
	&src1, name1, &src2, name2,
	opt->repo->index, &ll_opts);

	free(base);
	free(name1);
	free(name2);
	free(orig.ptr);
	free(src1.ptr);
	free(src2.ptr);
	return merge_status;
	}

	static int find_first_merges(struct repository *repo,
	struct object_array result, const char path,
	struct commit a, struct commit b)
	{
	int i, j;
	struct object_array merges = OBJECT_ARRAY_INIT;
	struct commit *commit;
	int contains_another;

	char merged_revision[GIT_MAX_HEXSZ + 2];
	const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
	"--all", merged_revision, NULL };
	struct rev_info revs;
	struct setup_revision_opt rev_opts;

	memset(result, 0, sizeof(struct object_array));
	memset(&rev_opts, 0, sizeof(rev_opts));

	/* get all revisions that merge commit a */
	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
	oid_to_hex(&a->object.oid));
	repo_init_revisions(repo, &revs, NULL);
	rev_opts.submodule = path;
	/* FIXME: can't handle linked worktrees in submodules yet */
	revs.single_worktree = path != NULL;
	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);

	/* save all revisions from the above list that contain b */
	if (prepare_revision_walk(&revs))
	die("revision walk setup failed");
	while ((commit = get_revision(&revs)) != NULL) {
	struct object *o = &(commit->object);
	if (in_merge_bases(b, commit))
	add_object_array(o, NULL, &merges);
	}
	reset_revision_walk();

	/* Now we've got all merges that contain a and b. Prune all
	* merges that contain another found merge and save them in
	* result.
	*/
	for (i = 0; i < merges.nr; i++) {
	struct commit m1 = (struct commit ) merges.objects[i].item;

	contains_another = 0;
	for (j = 0; j < merges.nr; j++) {
	struct commit m2 = (struct commit ) merges.objects[j].item;
	if (i != j && in_merge_bases(m2, m1)) {
	contains_another = 1;
	break;
	}
	}

	if (!contains_another)
	add_object_array(merges.objects[i].item, NULL, result);
	}

	object_array_clear(&merges);
	return result->nr;
	}

	static void print_commit(struct commit *commit)
	{
	struct strbuf sb = STRBUF_INIT;
	struct pretty_print_context ctx = {0};
	ctx.date_mode.type = DATE_NORMAL;
	/* FIXME: Merge this with output_commit_title() */
	assert(!merge_remote_util(commit));
	format_commit_message(commit, " %h: %m %s", &sb, &ctx);
	fprintf(stderr, "%s\n", sb.buf);
	strbuf_release(&sb);
	}

	static int is_valid(const struct diff_filespec *dfs)
	{
	return dfs->mode != 0 && !is_null_oid(&dfs->oid);
	}

	static int merge_submodule(struct merge_options *opt,
	struct object_id result, const char path,
	const struct object_id base, const struct object_id a,
	const struct object_id *b)
	{
	struct commit commit_base, commit_a, *commit_b;
	int parent_count;
	struct object_array merges;

	int i;
	int search = !opt->priv->call_depth;

	/* store a in result in case we fail */
	/* FIXME: This is the WRONG resolution for the recursive case when
	* we need to be careful to avoid accidentally matching either side.
	* Should probably use o instead there, much like we do for merging
	* binaries.
	*/
	oidcpy(result, a);

	/* we can not handle deletion conflicts */
	if (is_null_oid(base))
	return 0;
	if (is_null_oid(a))
	return 0;
	if (is_null_oid(b))
	return 0;

	if (add_submodule_odb(path)) {
	output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
	return 0;
	}

	if (!(commit_base = lookup_commit_reference(opt->repo, base)) \|\|
	!(commit_a = lookup_commit_reference(opt->repo, a)) \|\|
	!(commit_b = lookup_commit_reference(opt->repo, b))) {
	output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
	return 0;
	}

	/* check whether both changes are forward */
	if (!in_merge_bases(commit_base, commit_a) \|\|
	!in_merge_bases(commit_base, commit_b)) {
	output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
	return 0;
	}

	/* Case #1: a is contained in b or vice versa */
	if (in_merge_bases(commit_a, commit_b)) {
	oidcpy(result, b);
	if (show(opt, 3)) {
	output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
	output_commit_title(opt, commit_b);
	} else if (show(opt, 2))
	output(opt, 2, _("Fast-forwarding submodule %s"), path);
	else
	; /* no output */

	return 1;
	}
	if (in_merge_bases(commit_b, commit_a)) {
	oidcpy(result, a);
	if (show(opt, 3)) {
	output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
	output_commit_title(opt, commit_a);
	} else if (show(opt, 2))
	output(opt, 2, _("Fast-forwarding submodule %s"), path);
	else
	; /* no output */

	return 1;
	}

	/*
	* Case #2: There are one or more merges that contain a and b in
	* the submodule. If there is only one, then present it as a
	* suggestion to the user, but leave it marked unmerged so the
	* user needs to confirm the resolution.
	*/

	/* Skip the search if makes no sense to the calling context. */
	if (!search)
	return 0;

	/* find commit which merges them */
	parent_count = find_first_merges(opt->repo, &merges, path,
	commit_a, commit_b);
	switch (parent_count) {
	case 0:
	output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
	break;

	case 1:
	output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
	output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
	print_commit((struct commit *) merges.objects[0].item);
	output(opt, 2, _(
	"If this is correct simply add it to the index "
	"for example\n"
	"by using:\n\n"
	" git update-index --cacheinfo 160000 %s \"%s\"\n\n"
	"which will accept this suggestion.\n"),
	oid_to_hex(&merges.objects[0].item->oid), path);
	break;

	default:
	output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
	for (i = 0; i < merges.nr; i++)
	print_commit((struct commit *) merges.objects[i].item);
	}

	object_array_clear(&merges);
	return 0;
	}

	static int merge_mode_and_contents(struct merge_options *opt,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b,
	const char *filename,
	const char *branch1,
	const char *branch2,
	const int extra_marker_size,
	struct merge_file_info *result)
	{
	if (opt->branch1 != branch1) {
	/*
	* It's weird getting a reverse merge with HEAD on the bottom
	* side of the conflict markers and the other branch on the
	* top. Fix that.
	*/
	return merge_mode_and_contents(opt, o, b, a,
	filename,
	branch2, branch1,
	extra_marker_size, result);
	}

	result->merge = 0;
	result->clean = 1;

	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
	result->clean = 0;
	/*
	* FIXME: This is a bad resolution for recursive case; for
	* the recursive case we want something that is unlikely to
	* accidentally match either side. Also, while it makes
	* sense to prefer regular files over symlinks, it doesn't
	* make sense to prefer regular files over submodules.
	*/
	if (S_ISREG(a->mode)) {
	result->blob.mode = a->mode;
	oidcpy(&result->blob.oid, &a->oid);
	} else {
	result->blob.mode = b->mode;
	oidcpy(&result->blob.oid, &b->oid);
	}
	} else {
	if (!oideq(&a->oid, &o->oid) && !oideq(&b->oid, &o->oid))
	result->merge = 1;

	/*
	* Merge modes
	*/
	if (a->mode == b->mode \|\| a->mode == o->mode)
	result->blob.mode = b->mode;
	else {
	result->blob.mode = a->mode;
	if (b->mode != o->mode) {
	result->clean = 0;
	result->merge = 1;
	}
	}

	if (oideq(&a->oid, &b->oid) \|\| oideq(&a->oid, &o->oid))
	oidcpy(&result->blob.oid, &b->oid);
	else if (oideq(&b->oid, &o->oid))
	oidcpy(&result->blob.oid, &a->oid);
	else if (S_ISREG(a->mode)) {
	mmbuffer_t result_buf;
	int ret = 0, merge_status;

	merge_status = merge_3way(opt, &result_buf, o, a, b,
	branch1, branch2,
	extra_marker_size);

	if ((merge_status < 0) \|\| !result_buf.ptr)
	ret = err(opt, _("Failed to execute internal merge"));

	if (!ret &&
	write_object_file(result_buf.ptr, result_buf.size,
	blob_type, &result->blob.oid))
	ret = err(opt, _("Unable to add %s to database"),
	a->path);

	free(result_buf.ptr);
	if (ret)
	return ret;
	/* FIXME: bug, what if modes didn't match? */
	result->clean = (merge_status == 0);
	} else if (S_ISGITLINK(a->mode)) {
	result->clean = merge_submodule(opt, &result->blob.oid,
	o->path,
	&o->oid,
	&a->oid,
	&b->oid);
	} else if (S_ISLNK(a->mode)) {
	switch (opt->recursive_variant) {
	case MERGE_VARIANT_NORMAL:
	oidcpy(&result->blob.oid, &a->oid);
	if (!oideq(&a->oid, &b->oid))
	result->clean = 0;
	break;
	case MERGE_VARIANT_OURS:
	oidcpy(&result->blob.oid, &a->oid);
	break;
	case MERGE_VARIANT_THEIRS:
	oidcpy(&result->blob.oid, &b->oid);
	break;
	}
	} else
	BUG("unsupported object type in the tree");
	}

	if (result->merge)
	output(opt, 2, _("Auto-merging %s"), filename);

	return 0;
	}

	static int handle_rename_via_dir(struct merge_options *opt,
	struct rename_conflict_info *ci)
	{
	/*
	* Handle file adds that need to be renamed due to directory rename
	* detection. This differs from handle_rename_normal, because
	* there is no content merge to do; just move the file into the
	* desired final location.
	*/
	const struct rename *ren = ci->ren1;
	const struct diff_filespec *dest = ren->pair->two;
	char *file_path = dest->path;
	int mark_conflicted = (opt->detect_directory_renames ==
	MERGE_DIRECTORY_RENAMES_CONFLICT);
	assert(ren->dir_rename_original_dest);

	if (!opt->priv->call_depth && would_lose_untracked(opt, dest->path)) {
	mark_conflicted = 1;
	file_path = unique_path(opt, dest->path, ren->branch);
	output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
	"writing to %s instead."),
	dest->path, file_path);
	}

	if (mark_conflicted) {
	/*
	* Write the file in worktree at file_path. In the index,
	* only record the file at dest->path in the appropriate
	* higher stage.
	*/
	if (update_file(opt, 0, dest, file_path))
	return -1;
	if (file_path != dest->path)
	free(file_path);
	if (update_stages(opt, dest->path, NULL,
	ren->branch == opt->branch1 ? dest : NULL,
	ren->branch == opt->branch1 ? NULL : dest))
	return -1;
	return 0; /* not clean, but conflicted */
	} else {
	/* Update dest->path both in index and in worktree */
	if (update_file(opt, 1, dest, dest->path))
	return -1;
	return 1; /* clean */
	}
	}

	static int handle_change_delete(struct merge_options *opt,
	const char path, const char old_path,
	const struct diff_filespec *o,
	const struct diff_filespec *changed,
	const char *change_branch,
	const char *delete_branch,
	const char change, const char change_past)
	{
	char *alt_path = NULL;
	const char *update_path = path;
	int ret = 0;

	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0) \|\|
	(!opt->priv->call_depth && would_lose_untracked(opt, path))) {
	update_path = alt_path = unique_path(opt, path, change_branch);
	}

	if (opt->priv->call_depth) {
	/*
	* We cannot arbitrarily accept either a_sha or b_sha as
	* correct; since there is no true "middle point" between
	* them, simply reuse the base version for virtual merge base.
	*/
	ret = remove_file_from_index(opt->repo->index, path);
	if (!ret)
	ret = update_file(opt, 0, o, update_path);
	} else {
	/*
	* Despite the four nearly duplicate messages and argument
	* lists below and the ugliness of the nested if-statements,
	* having complete messages makes the job easier for
	* translators.
	*
	* The slight variance among the cases is due to the fact
	* that:
	* 1) directory/file conflicts (in effect if
	* !alt_path) could cause us to need to write the
	* file to a different path.
	* 2) renames (in effect if !old_path) could mean that
	* there are two names for the path that the user
	* may know the file by.
	*/
	if (!alt_path) {
	if (!old_path) {
	output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
	"and %s in %s. Version %s of %s left in tree."),
	change, path, delete_branch, change_past,
	change_branch, change_branch, path);
	} else {
	output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
	"and %s to %s in %s. Version %s of %s left in tree."),
	change, old_path, delete_branch, change_past, path,
	change_branch, change_branch, path);
	}
	} else {
	if (!old_path) {
	output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
	"and %s in %s. Version %s of %s left in tree at %s."),
	change, path, delete_branch, change_past,
	change_branch, change_branch, path, alt_path);
	} else {
	output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
	"and %s to %s in %s. Version %s of %s left in tree at %s."),
	change, old_path, delete_branch, change_past, path,
	change_branch, change_branch, path, alt_path);
	}
	}
	/*
	* No need to call update_file() on path when change_branch ==
	* opt->branch1 && !alt_path, since that would needlessly touch
	* path. We could call update_file_flags() with update_cache=0
	* and update_wd=0, but that's a no-op.
	*/
	if (change_branch != opt->branch1 \|\| alt_path)
	ret = update_file(opt, 0, changed, update_path);
	}
	free(alt_path);

	return ret;
	}

	static int handle_rename_delete(struct merge_options *opt,
	struct rename_conflict_info *ci)
	{
	const struct rename *ren = ci->ren1;
	const struct diff_filespec *orig = ren->pair->one;
	const struct diff_filespec *dest = ren->pair->two;
	const char *rename_branch = ren->branch;
	const char *delete_branch = (opt->branch1 == ren->branch ?
	opt->branch2 : opt->branch1);

	if (handle_change_delete(opt,
	opt->priv->call_depth ? orig->path : dest->path,
	opt->priv->call_depth ? NULL : orig->path,
	orig, dest,
	rename_branch, delete_branch,
	_("rename"), _("renamed")))
	return -1;

	if (opt->priv->call_depth)
	return remove_file_from_index(opt->repo->index, dest->path);
	else
	return update_stages(opt, dest->path, NULL,
	rename_branch == opt->branch1 ? dest : NULL,
	rename_branch == opt->branch1 ? NULL : dest);
	}

	static int handle_file_collision(struct merge_options *opt,
	const char *collide_path,
	const char *prev_path1,
	const char *prev_path2,
	const char branch1, const char branch2,
	struct diff_filespec *a,
	struct diff_filespec *b)
	{
	struct merge_file_info mfi;
	struct diff_filespec null;
	char *alt_path = NULL;
	const char *update_path = collide_path;

	/*
	* It's easiest to get the correct things into stage 2 and 3, and
	* to make sure that the content merge puts HEAD before the other
	* branch if we just ensure that branch1 == opt->branch1. So, simply
	* flip arguments around if we don't have that.
	*/
	if (branch1 != opt->branch1) {
	return handle_file_collision(opt, collide_path,
	prev_path2, prev_path1,
	branch2, branch1,
	b, a);
	}

	/* Remove rename sources if rename/add or rename/rename(2to1) */
	if (prev_path1)
	remove_file(opt, 1, prev_path1,
	opt->priv->call_depth \|\| would_lose_untracked(opt, prev_path1));
	if (prev_path2)
	remove_file(opt, 1, prev_path2,
	opt->priv->call_depth \|\| would_lose_untracked(opt, prev_path2));

	/*
	* Remove the collision path, if it wouldn't cause dirty contents
	* or an untracked file to get lost. We'll either overwrite with
	* merged contents, or just write out to differently named files.
	*/
	if (was_dirty(opt, collide_path)) {
	output(opt, 1, _("Refusing to lose dirty file at %s"),
	collide_path);
	update_path = alt_path = unique_path(opt, collide_path, "merged");
	} else if (would_lose_untracked(opt, collide_path)) {
	/*
	* Only way we get here is if both renames were from
	* a directory rename AND user had an untracked file
	* at the location where both files end up after the
	* two directory renames. See testcase 10d of t6043.
	*/
	output(opt, 1, _("Refusing to lose untracked file at "
	"%s, even though it's in the way."),
	collide_path);
	update_path = alt_path = unique_path(opt, collide_path, "merged");
	} else {
	/*
	* FIXME: It's possible that the two files are identical
	* and that the current working copy happens to match, in
	* which case we are unnecessarily touching the working
	* tree file. It's not a likely enough scenario that I
	* want to code up the checks for it and a better fix is
	* available if we restructure how unpack_trees() and
	* merge-recursive interoperate anyway, so punting for
	* now...
	*/
	remove_file(opt, 0, collide_path, 0);
	}

	/* Store things in diff_filespecs for functions that need it */
	null.path = (char *)collide_path;
	oidcpy(&null.oid, &null_oid);
	null.mode = 0;

	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
	branch1, branch2, opt->priv->call_depth * 2, &mfi))
	return -1;
	mfi.clean &= !alt_path;
	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
	return -1;
	if (!mfi.clean && !opt->priv->call_depth &&
	update_stages(opt, collide_path, NULL, a, b))
	return -1;
	free(alt_path);
	/*
	* FIXME: If both a & b both started with conflicts (only possible
	* if they came from a rename/rename(2to1)), but had IDENTICAL
	* contents including those conflicts, then in the next line we claim
	* it was clean. If someone cares about this case, we should have the
	* caller notify us if we started with conflicts.
	*/
	return mfi.clean;
	}

	static int handle_rename_add(struct merge_options *opt,
	struct rename_conflict_info *ci)
	{
	/* a was renamed to c, and a separate c was added. */
	struct diff_filespec *a = ci->ren1->pair->one;
	struct diff_filespec *c = ci->ren1->pair->two;
	char *path = c->path;
	char *prev_path_desc;
	struct merge_file_info mfi;

	const char *rename_branch = ci->ren1->branch;
	const char *add_branch = (opt->branch1 == rename_branch ?
	opt->branch2 : opt->branch1);
	int other_stage = (ci->ren1->branch == opt->branch1 ? 3 : 2);

	output(opt, 1, _("CONFLICT (rename/add): "
	"Rename %s->%s in %s. Added %s in %s"),
	a->path, c->path, rename_branch,
	c->path, add_branch);

	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
	ci->ren1->src_entry->stages[other_stage].path = a->path;
	if (merge_mode_and_contents(opt, a, c,
	&ci->ren1->src_entry->stages[other_stage],
	prev_path_desc,
	opt->branch1, opt->branch2,
	1 + opt->priv->call_depth * 2, &mfi))
	return -1;
	free(prev_path_desc);

	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
	return handle_file_collision(opt,
	c->path, a->path, NULL,
	rename_branch, add_branch,
	&mfi.blob,
	&ci->ren1->dst_entry->stages[other_stage]);
	}

	static char find_path_for_conflict(struct merge_options opt,
	const char *path,
	const char *branch1,
	const char *branch2)
	{
	char *new_path = NULL;
	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0)) {
	new_path = unique_path(opt, path, branch1);
	output(opt, 1, _("%s is a directory in %s adding "
	"as %s instead"),
	path, branch2, new_path);
	} else if (would_lose_untracked(opt, path)) {
	new_path = unique_path(opt, path, branch1);
	output(opt, 1, _("Refusing to lose untracked file"
	" at %s; adding as %s instead"),
	path, new_path);
	}

	return new_path;
	}

	/*
	* Toggle the stage number between "ours" and "theirs" (2 and 3).
	*/
	static inline int flip_stage(int stage)
	{
	return (2 + 3) - stage;
	}

	static int handle_rename_rename_1to2(struct merge_options *opt,
	struct rename_conflict_info *ci)
	{
	/* One file was renamed in both branches, but to different names. */
	struct merge_file_info mfi;
	struct diff_filespec *add;
	struct diff_filespec *o = ci->ren1->pair->one;
	struct diff_filespec *a = ci->ren1->pair->two;
	struct diff_filespec *b = ci->ren2->pair->two;
	char *path_desc;

	output(opt, 1, _("CONFLICT (rename/rename): "
	"Rename \"%s\"->\"%s\" in branch \"%s\" "
	"rename \"%s\"->\"%s\" in \"%s\"%s"),
	o->path, a->path, ci->ren1->branch,
	o->path, b->path, ci->ren2->branch,
	opt->priv->call_depth ? _(" (left unresolved)") : "");

	path_desc = xstrfmt("%s and %s, both renamed from %s",
	a->path, b->path, o->path);
	if (merge_mode_and_contents(opt, o, a, b, path_desc,
	ci->ren1->branch, ci->ren2->branch,
	opt->priv->call_depth * 2, &mfi))
	return -1;
	free(path_desc);

	if (opt->priv->call_depth)
	remove_file_from_index(opt->repo->index, o->path);

	/*
	* For each destination path, we need to see if there is a
	* rename/add collision. If not, we can write the file out
	* to the specified location.
	*/
	add = &ci->ren1->dst_entry->stages[flip_stage(2)];
	if (is_valid(add)) {
	add->path = mfi.blob.path = a->path;
	if (handle_file_collision(opt, a->path,
	NULL, NULL,
	ci->ren1->branch,
	ci->ren2->branch,
	&mfi.blob, add) < 0)
	return -1;
	} else {
	char *new_path = find_path_for_conflict(opt, a->path,
	ci->ren1->branch,
	ci->ren2->branch);
	if (update_file(opt, 0, &mfi.blob,
	new_path ? new_path : a->path))
	return -1;
	free(new_path);
	if (!opt->priv->call_depth &&
	update_stages(opt, a->path, NULL, a, NULL))
	return -1;
	}

	if (!mfi.clean && mfi.blob.mode == a->mode &&
	oideq(&mfi.blob.oid, &a->oid)) {
	/*
	* Getting here means we were attempting to merge a binary
	* blob. Since we can't merge binaries, the merge algorithm
	* just takes one side. But we don't want to copy the
	* contents of one side to both paths; we'd rather use the
	* original content at the given path for each path.
	*/
	oidcpy(&mfi.blob.oid, &b->oid);
	mfi.blob.mode = b->mode;
	}
	add = &ci->ren2->dst_entry->stages[flip_stage(3)];
	if (is_valid(add)) {
	add->path = mfi.blob.path = b->path;
	if (handle_file_collision(opt, b->path,
	NULL, NULL,
	ci->ren1->branch,
	ci->ren2->branch,
	add, &mfi.blob) < 0)
	return -1;
	} else {
	char *new_path = find_path_for_conflict(opt, b->path,
	ci->ren2->branch,
	ci->ren1->branch);
	if (update_file(opt, 0, &mfi.blob,
	new_path ? new_path : b->path))
	return -1;
	free(new_path);
	if (!opt->priv->call_depth &&
	update_stages(opt, b->path, NULL, NULL, b))
	return -1;
	}

	return 0;
	}

	static int handle_rename_rename_2to1(struct merge_options *opt,
	struct rename_conflict_info *ci)
	{
	/* Two files, a & b, were renamed to the same thing, c. */
	struct diff_filespec *a = ci->ren1->pair->one;
	struct diff_filespec *b = ci->ren2->pair->one;
	struct diff_filespec *c1 = ci->ren1->pair->two;
	struct diff_filespec *c2 = ci->ren2->pair->two;
	char path = c1->path; / == c2->path */
	char *path_side_1_desc;
	char *path_side_2_desc;
	struct merge_file_info mfi_c1;
	struct merge_file_info mfi_c2;
	int ostage1, ostage2;

	output(opt, 1, _("CONFLICT (rename/rename): "
	"Rename %s->%s in %s. "
	"Rename %s->%s in %s"),
	a->path, c1->path, ci->ren1->branch,
	b->path, c2->path, ci->ren2->branch);

	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
	ostage2 = flip_stage(ostage1);
	ci->ren1->src_entry->stages[ostage1].path = a->path;
	ci->ren2->src_entry->stages[ostage2].path = b->path;
	if (merge_mode_and_contents(opt, a, c1,
	&ci->ren1->src_entry->stages[ostage1],
	path_side_1_desc,
	opt->branch1, opt->branch2,
	1 + opt->priv->call_depth * 2, &mfi_c1) \|\|
	merge_mode_and_contents(opt, b,
	&ci->ren2->src_entry->stages[ostage2],
	c2, path_side_2_desc,
	opt->branch1, opt->branch2,
	1 + opt->priv->call_depth * 2, &mfi_c2))
	return -1;
	free(path_side_1_desc);
	free(path_side_2_desc);
	mfi_c1.blob.path = path;
	mfi_c2.blob.path = path;

	return handle_file_collision(opt, path, a->path, b->path,
	ci->ren1->branch, ci->ren2->branch,
	&mfi_c1.blob, &mfi_c2.blob);
	}

	/*
	* Get the diff_filepairs changed between o_tree and tree.
	*/
	static struct diff_queue_struct get_diffpairs(struct merge_options opt,
	struct tree *o_tree,
	struct tree *tree)
	{
	struct diff_queue_struct *ret;
	struct diff_options opts;

	repo_diff_setup(opt->repo, &opts);
	opts.flags.recursive = 1;
	opts.flags.rename_empty = 0;
	opts.detect_rename = merge_detect_rename(opt);
	/*
	* We do not have logic to handle the detection of copies. In
	* fact, it may not even make sense to add such logic: would we
	* really want a change to a base file to be propagated through
	* multiple other files by a merge?
	*/
	if (opts.detect_rename > DIFF_DETECT_RENAME)
	opts.detect_rename = DIFF_DETECT_RENAME;
	opts.rename_limit = (opt->rename_limit >= 0) ? opt->rename_limit : 1000;
	opts.rename_score = opt->rename_score;
	opts.show_rename_progress = opt->show_rename_progress;
	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_setup_done(&opts);
	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
	diffcore_std(&opts);
	if (opts.needed_rename_limit > opt->priv->needed_rename_limit)
	opt->priv->needed_rename_limit = opts.needed_rename_limit;

	ret = xmalloc(sizeof(*ret));
	*ret = diff_queued_diff;

	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
	diff_queued_diff.nr = 0;
	diff_queued_diff.queue = NULL;
	diff_flush(&opts);
	return ret;
	}

	static int tree_has_path(struct repository r, struct tree tree,
	const char *path)
	{
	struct object_id hashy;
	unsigned short mode_o;

	return !get_tree_entry(r,
	&tree->object.oid, path,
	&hashy, &mode_o);
	}

	/*
	* Return a new string that replaces the beginning portion (which matches
	* entry->dir), with entry->new_dir. In perl-speak:
	* new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
	* NOTE:
	* Caller must ensure that old_path starts with entry->dir + '/'.
	*/
	static char apply_dir_rename(struct dir_rename_entry entry,
	const char *old_path)
	{
	struct strbuf new_path = STRBUF_INIT;
	int oldlen, newlen;

	if (entry->non_unique_new_dir)
	return NULL;

	oldlen = strlen(entry->dir);
	if (entry->new_dir.len == 0)
	/*
	* If someone renamed/merged a subdirectory into the root
	* directory (e.g. 'some/subdir' -> ''), then we want to
	* avoid returning
	* '' + '/filename'
	* as the rename; we need to make old_path + oldlen advance
	* past the '/' character.
	*/
	oldlen++;
	newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
	strbuf_grow(&new_path, newlen);
	strbuf_addbuf(&new_path, &entry->new_dir);
	strbuf_addstr(&new_path, &old_path[oldlen]);

	return strbuf_detach(&new_path, NULL);
	}

	static void get_renamed_dir_portion(const char old_path, const char new_path,
	char old_dir, char new_dir)
	{
	char end_of_old, end_of_new;

	/* Default return values: NULL, meaning no rename */
	*old_dir = NULL;
	*new_dir = NULL;

	/*
	* For
	* "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
	* the "e/foo.c" part is the same, we just want to know that
	* "a/b/c/d" was renamed to "a/b/some/thing/else"
	* so, for this example, this function returns "a/b/c/d" in
	* old_dir and "a/b/some/thing/else" in new_dir.
	*/

	/*
	* If the basename of the file changed, we don't care. We want
	* to know which portion of the directory, if any, changed.
	*/
	end_of_old = strrchr(old_path, '/');
	end_of_new = strrchr(new_path, '/');

	/*
	* If end_of_old is NULL, old_path wasn't in a directory, so there
	* could not be a directory rename (our rule elsewhere that a
	* directory which still exists is not considered to have been
	* renamed means the root directory can never be renamed -- because
	* the root directory always exists).
	*/
	if (end_of_old == NULL)
	return; /* Note: old_dir and new_dir are still NULL */

	/*
	* If new_path contains no directory (end_of_new is NULL), then we
	* have a rename of old_path's directory to the root directory.
	*/
	if (end_of_new == NULL) {
	*old_dir = xstrndup(old_path, end_of_old - old_path);
	*new_dir = xstrdup("");
	return;
	}

	/* Find the first non-matching character traversing backwards */
	while (--end_of_new == --end_of_old &&
	end_of_old != old_path &&
	end_of_new != new_path)
	; /* Do nothing; all in the while loop */

	/*
	* If both got back to the beginning of their strings, then the
	* directory didn't change at all, only the basename did.
	*/
	if (end_of_old == old_path && end_of_new == new_path &&
	end_of_old == end_of_new)
	return; /* Note: old_dir and new_dir are still NULL */

	/*
	* If end_of_new got back to the beginning of its string, and
	* end_of_old got back to the beginning of some subdirectory, then
	* we have a rename/merge of a subdirectory into the root, which
	* needs slightly special handling.
	*
	* Note: There is no need to consider the opposite case, with a
	* rename/merge of the root directory into some subdirectory
	* because as noted above the root directory always exists so it
	* cannot be considered to be renamed.
	*/
	if (end_of_new == new_path &&
	end_of_old != old_path && end_of_old[-1] == '/') {
	*old_dir = xstrndup(old_path, --end_of_old - old_path);
	*new_dir = xstrdup("");
	return;
	}

	/*
	* We've found the first non-matching character in the directory
	* paths. That means the current characters we were looking at
	* were part of the first non-matching subdir name going back from
	* the end of the strings. Get the whole name by advancing both
	* end_of_old and end_of_new to the NEXT '/' character. That will
	* represent the entire directory rename.
	*
	* The reason for the increment is cases like
	* a/b/star/foo/whatever.c -> a/b/tar/foo/random.c
	* After dropping the basename and going back to the first
	* non-matching character, we're now comparing:
	* a/b/s and a/b/
	* and we want to be comparing:
	* a/b/star/ and a/b/tar/
	* but without the pre-increment, the one on the right would stay
	* a/b/.
	*/
	end_of_old = strchr(++end_of_old, '/');
	end_of_new = strchr(++end_of_new, '/');

	/* Copy the old and new directories into old_dir and new_dir. */
	*old_dir = xstrndup(old_path, end_of_old - old_path);
	*new_dir = xstrndup(new_path, end_of_new - new_path);
	}

	static void remove_hashmap_entries(struct hashmap *dir_renames,
	struct string_list *items_to_remove)
	{
	int i;
	struct dir_rename_entry *entry;

	for (i = 0; i < items_to_remove->nr; i++) {
	entry = items_to_remove->items[i].util;
	hashmap_remove(dir_renames, &entry->ent, NULL);
	}
	string_list_clear(items_to_remove, 0);
	}

	/*
	* See if there is a directory rename for path, and if there are any file
	* level conflicts for the renamed location. If there is a rename and
	* there are no conflicts, return the new name. Otherwise, return NULL.
	*/
	static char handle_path_level_conflicts(struct merge_options opt,
	const char *path,
	struct dir_rename_entry *entry,
	struct hashmap *collisions,
	struct tree *tree)
	{
	char *new_path = NULL;
	struct collision_entry *collision_ent;
	int clean = 1;
	struct strbuf collision_paths = STRBUF_INIT;

	/*
	* entry has the mapping of old directory name to new directory name
	* that we want to apply to path.
	*/
	new_path = apply_dir_rename(entry, path);

	if (!new_path) {
	/* This should only happen when entry->non_unique_new_dir set */
	if (!entry->non_unique_new_dir)
	BUG("entry->non_unqiue_dir not set and !new_path");
	output(opt, 1, _("CONFLICT (directory rename split): "
	"Unclear where to place %s because directory "
	"%s was renamed to multiple other directories, "
	"with no destination getting a majority of the "
	"files."),
	path, entry->dir);
	clean = 0;
	return NULL;
	}

	/*
	* The caller needs to have ensured that it has pre-populated
	* collisions with all paths that map to new_path. Do a quick check
	* to ensure that's the case.
	*/
	collision_ent = collision_find_entry(collisions, new_path);
	if (collision_ent == NULL)
	BUG("collision_ent is NULL");

	/*
	* Check for one-sided add/add/.../add conflicts, i.e.
	* where implicit renames from the other side doing
	* directory rename(s) can affect this side of history
	* to put multiple paths into the same location. Warn
	* and bail on directory renames for such paths.
	*/
	if (collision_ent->reported_already) {
	clean = 0;
	} else if (tree_has_path(opt->repo, tree, new_path)) {
	collision_ent->reported_already = 1;
	strbuf_add_separated_string_list(&collision_paths, ", ",
	&collision_ent->source_files);
	output(opt, 1, _("CONFLICT (implicit dir rename): Existing "
	"file/dir at %s in the way of implicit "
	"directory rename(s) putting the following "
	"path(s) there: %s."),
	new_path, collision_paths.buf);
	clean = 0;
	} else if (collision_ent->source_files.nr > 1) {
	collision_ent->reported_already = 1;
	strbuf_add_separated_string_list(&collision_paths, ", ",
	&collision_ent->source_files);
	output(opt, 1, _("CONFLICT (implicit dir rename): Cannot map "
	"more than one path to %s; implicit directory "
	"renames tried to put these paths there: %s"),
	new_path, collision_paths.buf);
	clean = 0;
	}

	/* Free memory we no longer need */
	strbuf_release(&collision_paths);
	if (!clean && new_path) {
	free(new_path);
	return NULL;
	}

	return new_path;
	}

	/*
	* There are a couple things we want to do at the directory level:
	* 1. Check for both sides renaming to the same thing, in order to avoid
	* implicit renaming of files that should be left in place. (See
	* testcase 6b in t6043 for details.)
	* 2. Prune directory renames if there are still files left in the
	* the original directory. These represent a partial directory rename,
	* i.e. a rename where only some of the files within the directory
	* were renamed elsewhere. (Technically, this could be done earlier
	* in get_directory_renames(), except that would prevent us from
	* doing the previous check and thus failing testcase 6b.)
	* 3. Check for rename/rename(1to2) conflicts (at the directory level).
	* In the future, we could potentially record this info as well and
	* omit reporting rename/rename(1to2) conflicts for each path within
	* the affected directories, thus cleaning up the merge output.
	* NOTE: We do NOT check for rename/rename(2to1) conflicts at the
	* directory level, because merging directories is fine. If it
	* causes conflicts for files within those merged directories, then
	* that should be detected at the individual path level.
	*/
	static void handle_directory_level_conflicts(struct merge_options *opt,
	struct hashmap *dir_re_head,
	struct tree *head,
	struct hashmap *dir_re_merge,
	struct tree *merge)
	{
	struct hashmap_iter iter;
	struct dir_rename_entry *head_ent;
	struct dir_rename_entry *merge_ent;

	struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
	struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;

	hashmap_for_each_entry(dir_re_head, &iter, head_ent,
	ent /* member name */) {
	merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
	if (merge_ent &&
	!head_ent->non_unique_new_dir &&
	!merge_ent->non_unique_new_dir &&
	!strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
	/* 1. Renamed identically; remove it from both sides */
	string_list_append(&remove_from_head,
	head_ent->dir)->util = head_ent;
	strbuf_release(&head_ent->new_dir);
	string_list_append(&remove_from_merge,
	merge_ent->dir)->util = merge_ent;
	strbuf_release(&merge_ent->new_dir);
	} else if (tree_has_path(opt->repo, head, head_ent->dir)) {
	/* 2. This wasn't a directory rename after all */
	string_list_append(&remove_from_head,
	head_ent->dir)->util = head_ent;
	strbuf_release(&head_ent->new_dir);
	}
	}

	remove_hashmap_entries(dir_re_head, &remove_from_head);
	remove_hashmap_entries(dir_re_merge, &remove_from_merge);

	hashmap_for_each_entry(dir_re_merge, &iter, merge_ent,
	ent /* member name */) {
	head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
	if (tree_has_path(opt->repo, merge, merge_ent->dir)) {
	/* 2. This wasn't a directory rename after all */
	string_list_append(&remove_from_merge,
	merge_ent->dir)->util = merge_ent;
	} else if (head_ent &&
	!head_ent->non_unique_new_dir &&
	!merge_ent->non_unique_new_dir) {
	/* 3. rename/rename(1to2) */
	/*
	* We can assume it's not rename/rename(1to1) because
	* that was case (1), already checked above. So we
	* know that head_ent->new_dir and merge_ent->new_dir
	* are different strings.
	*/
	output(opt, 1, _("CONFLICT (rename/rename): "
	"Rename directory %s->%s in %s. "
	"Rename directory %s->%s in %s"),
	head_ent->dir, head_ent->new_dir.buf, opt->branch1,
	head_ent->dir, merge_ent->new_dir.buf, opt->branch2);
	string_list_append(&remove_from_head,
	head_ent->dir)->util = head_ent;
	strbuf_release(&head_ent->new_dir);
	string_list_append(&remove_from_merge,
	merge_ent->dir)->util = merge_ent;
	strbuf_release(&merge_ent->new_dir);
	}
	}

	remove_hashmap_entries(dir_re_head, &remove_from_head);
	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
	}

	static struct hashmap get_directory_renames(struct diff_queue_struct pairs)
	{
	struct hashmap *dir_renames;
	struct hashmap_iter iter;
	struct dir_rename_entry *entry;
	int i;

	/*
	* Typically, we think of a directory rename as all files from a
	* certain directory being moved to a target directory. However,
	* what if someone first moved two files from the original
	* directory in one commit, and then renamed the directory
	* somewhere else in a later commit? At merge time, we just know
	* that files from the original directory went to two different
	* places, and that the bulk of them ended up in the same place.
	* We want each directory rename to represent where the bulk of the
	* files from that directory end up; this function exists to find
	* where the bulk of the files went.
	*
	* The first loop below simply iterates through the list of file
	* renames, finding out how often each directory rename pair
	* possibility occurs.
	*/
	dir_renames = xmalloc(sizeof(*dir_renames));
	dir_rename_init(dir_renames);
	for (i = 0; i < pairs->nr; ++i) {
	struct string_list_item *item;
	int *count;
	struct diff_filepair *pair = pairs->queue[i];
	char old_dir, new_dir;

	/* File not part of directory rename if it wasn't renamed */
	if (pair->status != 'R')
	continue;

	get_renamed_dir_portion(pair->one->path, pair->two->path,
	&old_dir, &new_dir);
	if (!old_dir)
	/* Directory didn't change at all; ignore this one. */
	continue;

	entry = dir_rename_find_entry(dir_renames, old_dir);
	if (!entry) {
	entry = xmalloc(sizeof(*entry));
	dir_rename_entry_init(entry, old_dir);
	hashmap_put(dir_renames, &entry->ent);
	} else {
	free(old_dir);
	}
	item = string_list_lookup(&entry->possible_new_dirs, new_dir);
	if (!item) {
	item = string_list_insert(&entry->possible_new_dirs,
	new_dir);
	item->util = xcalloc(1, sizeof(int));
	} else {
	free(new_dir);
	}
	count = item->util;
	*count += 1;
	}

	/*
	* For each directory with files moved out of it, we find out which
	* target directory received the most files so we can declare it to
	* be the "winning" target location for the directory rename. This
	* winner gets recorded in new_dir. If there is no winner
	* (multiple target directories received the same number of files),
	* we set non_unique_new_dir. Once we've determined the winner (or
	* that there is no winner), we no longer need possible_new_dirs.
	*/
	hashmap_for_each_entry(dir_renames, &iter, entry,
	ent /* member name */) {
	int max = 0;
	int bad_max = 0;
	char *best = NULL;

	for (i = 0; i < entry->possible_new_dirs.nr; i++) {
	int *count = entry->possible_new_dirs.items[i].util;

	if (*count == max)
	bad_max = max;
	else if (*count > max) {
	max = *count;
	best = entry->possible_new_dirs.items[i].string;
	}
	}
	if (bad_max == max)
	entry->non_unique_new_dir = 1;
	else {
	assert(entry->new_dir.len == 0);
	strbuf_addstr(&entry->new_dir, best);
	}
	/*
	* The relevant directory sub-portion of the original full
	* filepaths were xstrndup'ed before inserting into
	* possible_new_dirs, and instead of manually iterating the
	* list and free'ing each, just lie and tell
	* possible_new_dirs that it did the strdup'ing so that it
	* will free them for us.
	*/
	entry->possible_new_dirs.strdup_strings = 1;
	string_list_clear(&entry->possible_new_dirs, 1);
	}

	return dir_renames;
	}

	static struct dir_rename_entry check_dir_renamed(const char path,
	struct hashmap *dir_renames)
	{
	char *temp = xstrdup(path);
	char *end;
	struct dir_rename_entry *entry = NULL;

	while ((end = strrchr(temp, '/'))) {
	*end = '\0';
	entry = dir_rename_find_entry(dir_renames, temp);
	if (entry)
	break;
	}
	free(temp);
	return entry;
	}

	static void compute_collisions(struct hashmap *collisions,
	struct hashmap *dir_renames,
	struct diff_queue_struct *pairs)
	{
	int i;

	/*
	* Multiple files can be mapped to the same path due to directory
	* renames done by the other side of history. Since that other
	* side of history could have merged multiple directories into one,
	* if our side of history added the same file basename to each of
	* those directories, then all N of them would get implicitly
	* renamed by the directory rename detection into the same path,
	* and we'd get an add/add/.../add conflict, and all those adds
	* from this side of history. This is not representable in the
	* index, and users aren't going to easily be able to make sense of
	* it. So we need to provide a good warning about what's
	* happening, and fall back to no-directory-rename detection
	* behavior for those paths.
	*
	* See testcases 9e and all of section 5 from t6043 for examples.
	*/
	collision_init(collisions);

	for (i = 0; i < pairs->nr; ++i) {
	struct dir_rename_entry *dir_rename_ent;
	struct collision_entry *collision_ent;
	char *new_path;
	struct diff_filepair *pair = pairs->queue[i];

	if (pair->status != 'A' && pair->status != 'R')
	continue;
	dir_rename_ent = check_dir_renamed(pair->two->path,
	dir_renames);
	if (!dir_rename_ent)
	continue;

	new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
	if (!new_path)
	/*
	* dir_rename_ent->non_unique_new_path is true, which
	* means there is no directory rename for us to use,
	* which means it won't cause us any additional
	* collisions.
	*/
	continue;
	collision_ent = collision_find_entry(collisions, new_path);
	if (!collision_ent) {
	CALLOC_ARRAY(collision_ent, 1);
	hashmap_entry_init(&collision_ent->ent,
	strhash(new_path));
	hashmap_put(collisions, &collision_ent->ent);
	collision_ent->target_file = new_path;
	} else {
	free(new_path);
	}
	string_list_insert(&collision_ent->source_files,
	pair->two->path);
	}
	}

	static char check_for_directory_rename(struct merge_options opt,
	const char *path,
	struct tree *tree,
	struct hashmap *dir_renames,
	struct hashmap *dir_rename_exclusions,
	struct hashmap *collisions,
	int *clean_merge)
	{
	char *new_path = NULL;
	struct dir_rename_entry *entry = check_dir_renamed(path, dir_renames);
	struct dir_rename_entry *oentry = NULL;

	if (!entry)
	return new_path;

	/*
	* This next part is a little weird. We do not want to do an
	* implicit rename into a directory we renamed on our side, because
	* that will result in a spurious rename/rename(1to2) conflict. An
	* example:
	* Base commit: dumbdir/afile, otherdir/bfile
	* Side 1: smrtdir/afile, otherdir/bfile
	* Side 2: dumbdir/afile, dumbdir/bfile
	* Here, while working on Side 1, we could notice that otherdir was
	* renamed/merged to dumbdir, and change the diff_filepair for
	* otherdir/bfile into a rename into dumbdir/bfile. However, Side
	* 2 will notice the rename from dumbdir to smrtdir, and do the
	* transitive rename to move it from dumbdir/bfile to
	* smrtdir/bfile. That gives us bfile in dumbdir vs being in
	* smrtdir, a rename/rename(1to2) conflict. We really just want
	* the file to end up in smrtdir. And the way to achieve that is
	* to not let Side1 do the rename to dumbdir, since we know that is
	* the source of one of our directory renames.
	*
	* That's why oentry and dir_rename_exclusions is here.
	*
	* As it turns out, this also prevents N-way transient rename
	* confusion; See testcases 9c and 9d of t6043.
	*/
	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
	if (oentry) {
	output(opt, 1, _("WARNING: Avoiding applying %s -> %s rename "
	"to %s, because %s itself was renamed."),
	entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
	} else {
	new_path = handle_path_level_conflicts(opt, path, entry,
	collisions, tree);
	*clean_merge &= (new_path != NULL);
	}

	return new_path;
	}

	static void apply_directory_rename_modifications(struct merge_options *opt,
	struct diff_filepair *pair,
	char *new_path,
	struct rename *re,
	struct tree *tree,
	struct tree *o_tree,
	struct tree *a_tree,
	struct tree *b_tree,
	struct string_list *entries)
	{
	struct string_list_item *item;
	int stage = (tree == a_tree ? 2 : 3);
	int update_wd;

	/*
	* In all cases where we can do directory rename detection,
	* unpack_trees() will have read pair->two->path into the
	* index and the working copy. We need to remove it so that
	* we can instead place it at new_path. It is guaranteed to
	* not be untracked (unpack_trees() would have errored out
	* saying the file would have been overwritten), but it might
	* be dirty, though.
	*/
	update_wd = !was_dirty(opt, pair->two->path);
	if (!update_wd)
	output(opt, 1, _("Refusing to lose dirty file at %s"),
	pair->two->path);
	remove_file(opt, 1, pair->two->path, !update_wd);

	/* Find or create a new re->dst_entry */
	item = string_list_lookup(entries, new_path);
	if (item) {
	/*
	* Since we're renaming on this side of history, and it's
	* due to a directory rename on the other side of history
	* (which we only allow when the directory in question no
	* longer exists on the other side of history), the
	* original entry for re->dst_entry is no longer
	* necessary...
	*/
	re->dst_entry->processed = 1;

	/*
	* ...because we'll be using this new one.
	*/
	re->dst_entry = item->util;
	} else {
	/*
	* re->dst_entry is for the before-dir-rename path, and we
	* need it to hold information for the after-dir-rename
	* path. Before creating a new entry, we need to mark the
	* old one as unnecessary (...unless it is shared by
	* src_entry, i.e. this didn't use to be a rename, in which
	* case we can just allow the normal processing to happen
	* for it).
	*/
	if (pair->status == 'R')
	re->dst_entry->processed = 1;

	re->dst_entry = insert_stage_data(opt->repo, new_path,
	o_tree, a_tree, b_tree,
	entries);
	item = string_list_insert(entries, new_path);
	item->util = re->dst_entry;
	}

	/*
	* Update the stage_data with the information about the path we are
	* moving into place. That slot will be empty and available for us
	* to write to because of the collision checks in
	* handle_path_level_conflicts(). In other words,
	* re->dst_entry->stages[stage].oid will be the null_oid, so it's
	* open for us to write to.
	*
	* It may be tempting to actually update the index at this point as
	* well, using update_stages_for_stage_data(), but as per the big
	* "NOTE" in update_stages(), doing so will modify the current
	* in-memory index which will break calls to would_lose_untracked()
	* that we need to make. Instead, we need to just make sure that
	* the various handle_rename_*() functions update the index
	* explicitly rather than relying on unpack_trees() to have done it.
	*/
	get_tree_entry(opt->repo,
	&tree->object.oid,
	pair->two->path,
	&re->dst_entry->stages[stage].oid,
	&re->dst_entry->stages[stage].mode);

	/*
	* Record the original change status (or 'type' of change). If it
	* was originally an add ('A'), this lets us differentiate later
	* between a RENAME_DELETE conflict and RENAME_VIA_DIR (they
	* otherwise look the same). If it was originally a rename ('R'),
	* this lets us remember and report accurately about the transitive
	* renaming that occurred via the directory rename detection. Also,
	* record the original destination name.
	*/
	re->dir_rename_original_type = pair->status;
	re->dir_rename_original_dest = pair->two->path;

	/*
	* We don't actually look at pair->status again, but it seems
	* pedagogically correct to adjust it.
	*/
	pair->status = 'R';

	/*
	* Finally, record the new location.
	*/
	pair->two->path = new_path;
	}

	/*
	* Get information of all renames which occurred in 'pairs', making use of
	* any implicit directory renames inferred from the other side of history.
	* 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.
	*/
	static struct string_list get_renames(struct merge_options opt,
	const char *branch,
	struct diff_queue_struct *pairs,
	struct hashmap *dir_renames,
	struct hashmap *dir_rename_exclusions,
	struct tree *tree,
	struct tree *o_tree,
	struct tree *a_tree,
	struct tree *b_tree,
	struct string_list *entries,
	int *clean_merge)
	{
	int i;
	struct hashmap collisions;
	struct hashmap_iter iter;
	struct collision_entry *e;
	struct string_list *renames;

	compute_collisions(&collisions, dir_renames, pairs);
	CALLOC_ARRAY(renames, 1);

	for (i = 0; i < pairs->nr; ++i) {
	struct string_list_item *item;
	struct rename *re;
	struct diff_filepair *pair = pairs->queue[i];
	char new_path; / non-NULL only with directory renames */

	if (pair->status != 'A' && pair->status != 'R') {
	diff_free_filepair(pair);
	continue;
	}
	new_path = check_for_directory_rename(opt, pair->two->path, tree,
	dir_renames,
	dir_rename_exclusions,
	&collisions,
	clean_merge);
	if (pair->status != 'R' && !new_path) {
	diff_free_filepair(pair);
	continue;
	}

	re = xmalloc(sizeof(*re));
	re->processed = 0;
	re->pair = pair;
	re->branch = branch;
	re->dir_rename_original_type = '\0';
	re->dir_rename_original_dest = NULL;
	item = string_list_lookup(entries, re->pair->one->path);
	if (!item)
	re->src_entry = insert_stage_data(opt->repo,
	re->pair->one->path,
	o_tree, a_tree, b_tree, entries);
	else
	re->src_entry = item->util;

	item = string_list_lookup(entries, re->pair->two->path);
	if (!item)
	re->dst_entry = insert_stage_data(opt->repo,
	re->pair->two->path,
	o_tree, a_tree, b_tree, entries);
	else
	re->dst_entry = item->util;
	item = string_list_insert(renames, pair->one->path);
	item->util = re;
	if (new_path)
	apply_directory_rename_modifications(opt, pair, new_path,
	re, tree, o_tree,
	a_tree, b_tree,
	entries);
	}

	hashmap_for_each_entry(&collisions, &iter, e,
	ent /* member name */) {
	free(e->target_file);
	string_list_clear(&e->source_files, 0);
	}
	hashmap_clear_and_free(&collisions, struct collision_entry, ent);
	return renames;
	}

	static int process_renames(struct merge_options *opt,
	struct string_list *a_renames,
	struct string_list *b_renames)
	{
	int clean_merge = 1, i, j;
	struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
	struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
	const struct rename *sre;

	/*
	* FIXME: As string-list.h notes, it's O(n^2) to build a sorted
	* string_list one-by-one, but O(n log n) to build it unsorted and
	* then sort it. Note that as we build the list, we do not need to
	* check if the existing destination path is already in the list,
	* because the structure of diffcore_rename guarantees we won't
	* have duplicates.
	*/
	for (i = 0; i < a_renames->nr; i++) {
	sre = a_renames->items[i].util;
	string_list_insert(&a_by_dst, sre->pair->two->path)->util
	= (void *)sre;
	}
	for (i = 0; i < b_renames->nr; i++) {
	sre = b_renames->items[i].util;
	string_list_insert(&b_by_dst, sre->pair->two->path)->util
	= (void *)sre;
	}

	for (i = 0, j = 0; i < a_renames->nr \|\| j < b_renames->nr;) {
	struct string_list renames1, renames2Dst;
	struct rename ren1 = NULL, ren2 = NULL;
	const char ren1_src, ren1_dst;
	struct string_list_item *lookup;

	if (i >= a_renames->nr) {
	ren2 = b_renames->items[j++].util;
	} else if (j >= b_renames->nr) {
	ren1 = a_renames->items[i++].util;
	} else {
	int compare = strcmp(a_renames->items[i].string,
	b_renames->items[j].string);
	if (compare <= 0)
	ren1 = a_renames->items[i++].util;
	if (compare >= 0)
	ren2 = b_renames->items[j++].util;
	}

	/* TODO: refactor, so that 1/2 are not needed */
	if (ren1) {
	renames1 = a_renames;
	renames2Dst = &b_by_dst;
	} else {
	renames1 = b_renames;
	renames2Dst = &a_by_dst;
	SWAP(ren2, ren1);
	}

	if (ren1->processed)
	continue;
	ren1->processed = 1;
	ren1->dst_entry->processed = 1;
	/* BUG: We should only mark src_entry as processed if we
	* are not dealing with a rename + add-source case.
	*/
	ren1->src_entry->processed = 1;

	ren1_src = ren1->pair->one->path;
	ren1_dst = ren1->pair->two->path;

	if (ren2) {
	/* One file renamed on both sides */
	const char *ren2_src = ren2->pair->one->path;
	const char *ren2_dst = ren2->pair->two->path;
	enum rename_type rename_type;
	if (strcmp(ren1_src, ren2_src) != 0)
	BUG("ren1_src != ren2_src");
	ren2->dst_entry->processed = 1;
	ren2->processed = 1;
	if (strcmp(ren1_dst, ren2_dst) != 0) {
	rename_type = RENAME_ONE_FILE_TO_TWO;
	clean_merge = 0;
	} else {
	rename_type = RENAME_ONE_FILE_TO_ONE;
	/* BUG: We should only remove ren1_src in
	* the base stage (think of rename +
	* add-source cases).
	*/
	remove_file(opt, 1, ren1_src, 1);
	update_entry(ren1->dst_entry,
	ren1->pair->one,
	ren1->pair->two,
	ren2->pair->two);
	}
	setup_rename_conflict_info(rename_type, opt, ren1, ren2);
	} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
	/* Two different files renamed to the same thing */
	char *ren2_dst;
	ren2 = lookup->util;
	ren2_dst = ren2->pair->two->path;
	if (strcmp(ren1_dst, ren2_dst) != 0)
	BUG("ren1_dst != ren2_dst");

	clean_merge = 0;
	ren2->processed = 1;
	/*
	* BUG: We should only mark src_entry as processed
	* if we are not dealing with a rename + add-source
	* case.
	*/
	ren2->src_entry->processed = 1;

	setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
	opt, ren1, ren2);
	} else {
	/* Renamed in 1, maybe changed in 2 */
	/* we only use sha1 and mode of these */
	struct diff_filespec src_other, dst_other;
	int try_merge;

	/*
	* unpack_trees loads entries from common-commit
	* into stage 1, from head-commit into stage 2, and
	* from merge-commit into stage 3. We keep track
	* of which side corresponds to the rename.
	*/
	int renamed_stage = a_renames == renames1 ? 2 : 3;
	int other_stage = a_renames == renames1 ? 3 : 2;

	/* BUG: We should only remove ren1_src in the base
	* stage and in other_stage (think of rename +
	* add-source case).
	*/
	remove_file(opt, 1, ren1_src,
	renamed_stage == 2 \|\| !was_tracked(opt, ren1_src));

	oidcpy(&src_other.oid,
	&ren1->src_entry->stages[other_stage].oid);
	src_other.mode = ren1->src_entry->stages[other_stage].mode;
	oidcpy(&dst_other.oid,
	&ren1->dst_entry->stages[other_stage].oid);
	dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
	try_merge = 0;

	if (oideq(&src_other.oid, &null_oid) &&
	ren1->dir_rename_original_type == 'A') {
	setup_rename_conflict_info(RENAME_VIA_DIR,
	opt, ren1, NULL);
	} else if (oideq(&src_other.oid, &null_oid)) {
	setup_rename_conflict_info(RENAME_DELETE,
	opt, ren1, NULL);
	} else if ((dst_other.mode == ren1->pair->two->mode) &&
	oideq(&dst_other.oid, &ren1->pair->two->oid)) {
	/*
	* Added file on the other side identical to
	* the file being renamed: clean merge.
	* Also, there is no need to overwrite the
	* file already in the working copy, so call
	* update_file_flags() instead of
	* update_file().
	*/
	if (update_file_flags(opt,
	ren1->pair->two,
	ren1_dst,
	1, /* update_cache */
	0 /* update_wd */))
	clean_merge = -1;
	} else if (!oideq(&dst_other.oid, &null_oid)) {
	/*
	* Probably not a clean merge, but it's
	* premature to set clean_merge to 0 here,
	* because if the rename merges cleanly and
	* the merge exactly matches the newly added
	* file, then the merge will be clean.
	*/
	setup_rename_conflict_info(RENAME_ADD,
	opt, ren1, NULL);
	} else
	try_merge = 1;

	if (clean_merge < 0)
	goto cleanup_and_return;
	if (try_merge) {
	struct diff_filespec o, a, *b;
	src_other.path = (char *)ren1_src;

	o = ren1->pair->one;
	if (a_renames == renames1) {
	a = ren1->pair->two;
	b = &src_other;
	} else {
	b = ren1->pair->two;
	a = &src_other;
	}
	update_entry(ren1->dst_entry, o, a, b);
	setup_rename_conflict_info(RENAME_NORMAL,
	opt, ren1, NULL);
	}
	}
	}
	cleanup_and_return:
	string_list_clear(&a_by_dst, 0);
	string_list_clear(&b_by_dst, 0);

	return clean_merge;
	}

	struct rename_info {
	struct string_list *head_renames;
	struct string_list *merge_renames;
	};

	static void initial_cleanup_rename(struct diff_queue_struct *pairs,
	struct hashmap *dir_renames)
	{
	struct hashmap_iter iter;
	struct dir_rename_entry *e;

	hashmap_for_each_entry(dir_renames, &iter, e,
	ent /* member name */) {
	free(e->dir);
	strbuf_release(&e->new_dir);
	/* possible_new_dirs already cleared in get_directory_renames */
	}
	hashmap_clear_and_free(dir_renames, struct dir_rename_entry, ent);
	free(dir_renames);

	free(pairs->queue);
	free(pairs);
	}

	static int detect_and_process_renames(struct merge_options *opt,
	struct tree *common,
	struct tree *head,
	struct tree *merge,
	struct string_list *entries,
	struct rename_info *ri)
	{
	struct diff_queue_struct head_pairs, merge_pairs;
	struct hashmap dir_re_head, dir_re_merge;
	int clean = 1;

	ri->head_renames = NULL;
	ri->merge_renames = NULL;

	if (!merge_detect_rename(opt))
	return 1;

	head_pairs = get_diffpairs(opt, common, head);
	merge_pairs = get_diffpairs(opt, common, merge);

	if ((opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE) \|\|
	(opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
	!opt->priv->call_depth)) {
	dir_re_head = get_directory_renames(head_pairs);
	dir_re_merge = get_directory_renames(merge_pairs);

	handle_directory_level_conflicts(opt,
	dir_re_head, head,
	dir_re_merge, merge);
	} else {
	dir_re_head = xmalloc(sizeof(*dir_re_head));
	dir_re_merge = xmalloc(sizeof(*dir_re_merge));
	dir_rename_init(dir_re_head);
	dir_rename_init(dir_re_merge);
	}

	ri->head_renames = get_renames(opt, opt->branch1, head_pairs,
	dir_re_merge, dir_re_head, head,
	common, head, merge, entries,
	&clean);
	if (clean < 0)
	goto cleanup;
	ri->merge_renames = get_renames(opt, opt->branch2, merge_pairs,
	dir_re_head, dir_re_merge, merge,
	common, head, merge, entries,
	&clean);
	if (clean < 0)
	goto cleanup;
	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);

	cleanup:
	/*
	* Some cleanup is deferred until cleanup_renames() because the
	* data structures are still needed and referenced in
	* process_entry(). But there are a few things we can free now.
	*/
	initial_cleanup_rename(head_pairs, dir_re_head);
	initial_cleanup_rename(merge_pairs, dir_re_merge);

	return clean;
	}

	static void final_cleanup_rename(struct string_list *rename)
	{
	const struct rename *re;
	int i;

	if (rename == NULL)
	return;

	for (i = 0; i < rename->nr; i++) {
	re = rename->items[i].util;
	diff_free_filepair(re->pair);
	}
	string_list_clear(rename, 1);
	free(rename);
	}

	static void final_cleanup_renames(struct rename_info *re_info)
	{
	final_cleanup_rename(re_info->head_renames);
	final_cleanup_rename(re_info->merge_renames);
	}

	static int read_oid_strbuf(struct merge_options *opt,
	const struct object_id *oid,
	struct strbuf *dst)
	{
	void *buf;
	enum object_type type;
	unsigned long size;
	buf = read_object_file(oid, &type, &size);
	if (!buf)
	return err(opt, _("cannot read object %s"), oid_to_hex(oid));
	if (type != OBJ_BLOB) {
	free(buf);
	return err(opt, _("object %s is not a blob"), oid_to_hex(oid));
	}
	strbuf_attach(dst, buf, size, size + 1);
	return 0;
	}

	static int blob_unchanged(struct merge_options *opt,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	int renormalize, const char *path)
	{
	struct strbuf obuf = STRBUF_INIT;
	struct strbuf abuf = STRBUF_INIT;
	int ret = 0; /* assume changed for safety */
	struct index_state *idx = opt->repo->index;

	if (a->mode != o->mode)
	return 0;
	if (oideq(&o->oid, &a->oid))
	return 1;
	if (!renormalize)
	return 0;

	if (read_oid_strbuf(opt, &o->oid, &obuf) \|\|
	read_oid_strbuf(opt, &a->oid, &abuf))
	goto error_return;
	/*
	* Note: binary \| is used so that both renormalizations are
	* performed. Comparison can be skipped if both files are
	* unchanged since their sha1s have already been compared.
	*/
	if (renormalize_buffer(idx, path, obuf.buf, obuf.len, &obuf) \|
	renormalize_buffer(idx, path, abuf.buf, abuf.len, &abuf))
	ret = (obuf.len == abuf.len && !memcmp(obuf.buf, abuf.buf, obuf.len));

	error_return:
	strbuf_release(&obuf);
	strbuf_release(&abuf);
	return ret;
	}

	static int handle_modify_delete(struct merge_options *opt,
	const char *path,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b)
	{
	const char modify_branch, delete_branch;
	const struct diff_filespec *changed;

	if (is_valid(a)) {
	modify_branch = opt->branch1;
	delete_branch = opt->branch2;
	changed = a;
	} else {
	modify_branch = opt->branch2;
	delete_branch = opt->branch1;
	changed = b;
	}

	return handle_change_delete(opt,
	path, NULL,
	o, changed,
	modify_branch, delete_branch,
	_("modify"), _("modified"));
	}

	static int handle_content_merge(struct merge_file_info *mfi,
	struct merge_options *opt,
	const char *path,
	int is_dirty,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b,
	struct rename_conflict_info *ci)
	{
	const char *reason = _("content");
	unsigned df_conflict_remains = 0;

	if (!is_valid(o))
	reason = _("add/add");

	assert(o->path && a->path && b->path);
	if (ci && dir_in_way(opt->repo->index, path, !opt->priv->call_depth,
	S_ISGITLINK(ci->ren1->pair->two->mode)))
	df_conflict_remains = 1;

	if (merge_mode_and_contents(opt, o, a, b, path,
	opt->branch1, opt->branch2,
	opt->priv->call_depth * 2, mfi))
	return -1;

	/*
	* We can skip updating the working tree file iff:
	* a) The merge is clean
	* b) The merge matches what was in HEAD (content, mode, pathname)
	* c) The target path is usable (i.e. not involved in D/F conflict)
	*/
	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
	!df_conflict_remains) {
	int pos;
	struct cache_entry *ce;

	output(opt, 3, _("Skipped %s (merged same as existing)"), path);
	if (add_cacheinfo(opt, &mfi->blob, path,
	0, (!opt->priv->call_depth && !is_dirty), 0))
	return -1;
	/*
	* However, add_cacheinfo() will delete the old cache entry
	* and add a new one. We need to copy over any skip_worktree
	* flag to avoid making the file appear as if it were
	* deleted by the user.
	*/
	pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
	ce = opt->priv->orig_index.cache[pos];
	if (ce_skip_worktree(ce)) {
	pos = index_name_pos(opt->repo->index, path, strlen(path));
	ce = opt->repo->index->cache[pos];
	ce->ce_flags \|= CE_SKIP_WORKTREE;
	}
	return mfi->clean;
	}

	if (!mfi->clean) {
	if (S_ISGITLINK(mfi->blob.mode))
	reason = _("submodule");
	output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
	reason, path);
	if (ci && !df_conflict_remains)
	if (update_stages(opt, path, o, a, b))
	return -1;
	}

	if (df_conflict_remains \|\| is_dirty) {
	char *new_path;
	if (opt->priv->call_depth) {
	remove_file_from_index(opt->repo->index, path);
	} else {
	if (!mfi->clean) {
	if (update_stages(opt, path, o, a, b))
	return -1;
	} else {
	int file_from_stage2 = was_tracked(opt, path);

	if (update_stages(opt, path, NULL,
	file_from_stage2 ? &mfi->blob : NULL,
	file_from_stage2 ? NULL : &mfi->blob))
	return -1;
	}

	}
	new_path = unique_path(opt, path, ci->ren1->branch);
	if (is_dirty) {
	output(opt, 1, _("Refusing to lose dirty file at %s"),
	path);
	}
	output(opt, 1, _("Adding as %s instead"), new_path);
	if (update_file(opt, 0, &mfi->blob, new_path)) {
	free(new_path);
	return -1;
	}
	free(new_path);
	mfi->clean = 0;
	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
	return -1;
	return !is_dirty && mfi->clean;
	}

	static int handle_rename_normal(struct merge_options *opt,
	const char *path,
	const struct diff_filespec *o,
	const struct diff_filespec *a,
	const struct diff_filespec *b,
	struct rename_conflict_info *ci)
	{
	struct rename *ren = ci->ren1;
	struct merge_file_info mfi;
	int clean;
	int side = (ren->branch == opt->branch1 ? 2 : 3);

	/* Merge the content and write it out */
	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
	o, a, b, ci);

	if (clean &&
	opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
	ren->dir_rename_original_dest) {
	if (update_stages(opt, path,
	NULL,
	side == 2 ? &mfi.blob : NULL,
	side == 2 ? NULL : &mfi.blob))
	return -1;
	clean = 0; /* not clean, but conflicted */
	}
	return clean;
	}

	static void dir_rename_warning(const char *msg,
	int is_add,
	int clean,
	struct merge_options *opt,
	struct rename *ren)
	{
	const char *other_branch;
	other_branch = (ren->branch == opt->branch1 ?
	opt->branch2 : opt->branch1);
	if (is_add) {
	output(opt, clean ? 2 : 1, msg,
	ren->pair->one->path, ren->branch,
	other_branch, ren->pair->two->path);
	return;
	}
	output(opt, clean ? 2 : 1, msg,
	ren->pair->one->path, ren->dir_rename_original_dest, ren->branch,
	other_branch, ren->pair->two->path);
	}
	static int warn_about_dir_renamed_entries(struct merge_options *opt,
	struct rename *ren)
	{
	const char *msg;
	int clean = 1, is_add;

	if (!ren)
	return clean;

	/* Return early if ren was not affected/created by a directory rename */
	if (!ren->dir_rename_original_dest)
	return clean;

	/* Sanity checks */
	assert(opt->detect_directory_renames > MERGE_DIRECTORY_RENAMES_NONE);
	assert(ren->dir_rename_original_type == 'A' \|\|
	ren->dir_rename_original_type == 'R');

	/* Check whether to treat directory renames as a conflict */
	clean = (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE);

	is_add = (ren->dir_rename_original_type == 'A');
	if (ren->dir_rename_original_type == 'A' && clean) {
	msg = _("Path updated: %s added in %s inside a "
	"directory that was renamed in %s; moving it to %s.");
	} else if (ren->dir_rename_original_type == 'A' && !clean) {
	msg = _("CONFLICT (file location): %s added in %s "
	"inside a directory that was renamed in %s, "
	"suggesting it should perhaps be moved to %s.");
	} else if (ren->dir_rename_original_type == 'R' && clean) {
	msg = _("Path updated: %s renamed to %s in %s, inside a "
	"directory that was renamed in %s; moving it to %s.");
	} else if (ren->dir_rename_original_type == 'R' && !clean) {
	msg = _("CONFLICT (file location): %s renamed to %s in %s, "
	"inside a directory that was renamed in %s, "
	"suggesting it should perhaps be moved to %s.");
	} else {
	BUG("Impossible dir_rename_original_type/clean combination");
	}
	dir_rename_warning(msg, is_add, clean, opt, ren);

	return clean;
	}

	/* Per entry merge function */
	static int process_entry(struct merge_options *opt,
	const char path, struct stage_data entry)
	{
	int clean_merge = 1;
	int normalize = opt->renormalize;

	struct diff_filespec *o = &entry->stages[1];
	struct diff_filespec *a = &entry->stages[2];
	struct diff_filespec *b = &entry->stages[3];
	int o_valid = is_valid(o);
	int a_valid = is_valid(a);
	int b_valid = is_valid(b);
	o->path = a->path = b->path = (char*)path;

	entry->processed = 1;
	if (entry->rename_conflict_info) {
	struct rename_conflict_info *ci = entry->rename_conflict_info;
	struct diff_filespec *temp;
	int path_clean;

	path_clean = warn_about_dir_renamed_entries(opt, ci->ren1);
	path_clean &= warn_about_dir_renamed_entries(opt, ci->ren2);

	/*
	* For cases with a single rename, {o,a,b}->path have all been
	* set to the rename target path; we need to set two of these
	* back to the rename source.
	* For rename/rename conflicts, we'll manually fix paths below.
	*/
	temp = (opt->branch1 == ci->ren1->branch) ? b : a;
	o->path = temp->path = ci->ren1->pair->one->path;
	if (ci->ren2) {
	assert(opt->branch1 == ci->ren1->branch);
	}

	switch (ci->rename_type) {
	case RENAME_NORMAL:
	case RENAME_ONE_FILE_TO_ONE:
	clean_merge = handle_rename_normal(opt, path, o, a, b,
	ci);
	break;
	case RENAME_VIA_DIR:
	clean_merge = handle_rename_via_dir(opt, ci);
	break;
	case RENAME_ADD:
	/*
	* Probably unclean merge, but if the renamed file
	* merges cleanly and the result can then be
	* two-way merged cleanly with the added file, I
	* guess it's a clean merge?
	*/
	clean_merge = handle_rename_add(opt, ci);
	break;
	case RENAME_DELETE:
	clean_merge = 0;
	if (handle_rename_delete(opt, ci))
	clean_merge = -1;
	break;
	case RENAME_ONE_FILE_TO_TWO:
	/*
	* Manually fix up paths; note:
	* ren[12]->pair->one->path are equal.
	*/
	o->path = ci->ren1->pair->one->path;
	a->path = ci->ren1->pair->two->path;
	b->path = ci->ren2->pair->two->path;

	clean_merge = 0;
	if (handle_rename_rename_1to2(opt, ci))
	clean_merge = -1;
	break;
	case RENAME_TWO_FILES_TO_ONE:
	/*
	* Manually fix up paths; note,
	* ren[12]->pair->two->path are actually equal.
	*/
	o->path = NULL;
	a->path = ci->ren1->pair->two->path;
	b->path = ci->ren2->pair->two->path;

	/*
	* Probably unclean merge, but if the two renamed
	* files merge cleanly and the two resulting files
	* can then be two-way merged cleanly, I guess it's
	* a clean merge?
	*/
	clean_merge = handle_rename_rename_2to1(opt, ci);
	break;
	default:
	entry->processed = 0;
	break;
	}
	if (path_clean < clean_merge)
	clean_merge = path_clean;
	} else if (o_valid && (!a_valid \|\| !b_valid)) {
	/* Case A: Deleted in one */
	if ((!a_valid && !b_valid) \|\|
	(!b_valid && blob_unchanged(opt, o, a, normalize, path)) \|\|
	(!a_valid && blob_unchanged(opt, o, b, normalize, path))) {
	/* Deleted in both or deleted in one and
	* unchanged in the other */
	if (a_valid)
	output(opt, 2, _("Removing %s"), path);
	/* do not touch working file if it did not exist */
	remove_file(opt, 1, path, !a_valid);
	} else {
	/* Modify/delete; deleted side may have put a directory in the way */
	clean_merge = 0;
	if (handle_modify_delete(opt, path, o, a, b))
	clean_merge = -1;
	}
	} else if ((!o_valid && a_valid && !b_valid) \|\|
	(!o_valid && !a_valid && b_valid)) {
	/* Case B: Added in one. */
	/* [nothing\|directory] -> ([nothing\|directory], file) */

	const char *add_branch;
	const char *other_branch;
	const char *conf;
	const struct diff_filespec *contents;

	if (a_valid) {
	add_branch = opt->branch1;
	other_branch = opt->branch2;
	contents = a;
	conf = _("file/directory");
	} else {
	add_branch = opt->branch2;
	other_branch = opt->branch1;
	contents = b;
	conf = _("directory/file");
	}
	if (dir_in_way(opt->repo->index, path,
	!opt->priv->call_depth && !S_ISGITLINK(a->mode),
	0)) {
	char *new_path = unique_path(opt, path, add_branch);
	clean_merge = 0;
	output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
	"Adding %s as %s"),
	conf, path, other_branch, path, new_path);
	if (update_file(opt, 0, contents, new_path))
	clean_merge = -1;
	else if (opt->priv->call_depth)
	remove_file_from_index(opt->repo->index, path);
	free(new_path);
	} else {
	output(opt, 2, _("Adding %s"), path);
	/* do not overwrite file if already present */
	if (update_file_flags(opt, contents, path, 1, !a_valid))
	clean_merge = -1;
	}
	} else if (a_valid && b_valid) {
	if (!o_valid) {
	/* Case C: Added in both (check for same permissions) */
	output(opt, 1,
	_("CONFLICT (add/add): Merge conflict in %s"),
	path);
	clean_merge = handle_file_collision(opt,
	path, NULL, NULL,
	opt->branch1,
	opt->branch2,
	a, b);
	} else {
	/* case D: Modified in both, but differently. */
	struct merge_file_info mfi;
	int is_dirty = 0; /* unpack_trees would have bailed if dirty */
	clean_merge = handle_content_merge(&mfi, opt, path,
	is_dirty,
	o, a, b, NULL);
	}
	} else if (!o_valid && !a_valid && !b_valid) {
	/*
	* this entry was deleted altogether. a_mode == 0 means
	* we had that path and want to actively remove it.
	*/
	remove_file(opt, 1, path, !a->mode);
	} else
	BUG("fatal merge failure, shouldn't happen.");

	return clean_merge;
	}

	static int merge_trees_internal(struct merge_options *opt,
	struct tree *head,
	struct tree *merge,
	struct tree *merge_base,
	struct tree **result)
	{
	struct index_state *istate = opt->repo->index;
	int code, clean;

	if (opt->subtree_shift) {
	merge = shift_tree_object(opt->repo, head, merge,
	opt->subtree_shift);
	merge_base = shift_tree_object(opt->repo, head, merge_base,
	opt->subtree_shift);
	}

	if (oideq(&merge_base->object.oid, &merge->object.oid)) {
	output(opt, 0, _("Already up to date!"));
	*result = head;
	return 1;
	}

	code = unpack_trees_start(opt, merge_base, head, merge);

	if (code != 0) {
	if (show(opt, 4) \|\| opt->priv->call_depth)
	err(opt, _("merging of trees %s and %s failed"),
	oid_to_hex(&head->object.oid),
	oid_to_hex(&merge->object.oid));
	unpack_trees_finish(opt);
	return -1;
	}

	if (unmerged_index(istate)) {
	struct string_list *entries;
	struct rename_info re_info;
	int i;
	/*
	* Only need the hashmap while processing entries, so
	* initialize it here and free it when we are done running
	* through the entries. Keeping it in the merge_options as
	* opposed to decaring a local hashmap is for convenience
	* so that we don't have to pass it to around.
	*/
	hashmap_init(&opt->priv->current_file_dir_set, path_hashmap_cmp,
	NULL, 512);
	get_files_dirs(opt, head);
	get_files_dirs(opt, merge);

	entries = get_unmerged(opt->repo->index);
	clean = detect_and_process_renames(opt, merge_base, head, merge,
	entries, &re_info);
	record_df_conflict_files(opt, entries);
	if (clean < 0)
	goto cleanup;
	for (i = entries->nr-1; 0 <= i; i--) {
	const char *path = entries->items[i].string;
	struct stage_data *e = entries->items[i].util;
	if (!e->processed) {
	int ret = process_entry(opt, path, e);
	if (!ret)
	clean = 0;
	else if (ret < 0) {
	clean = ret;
	goto cleanup;
	}
	}
	}
	for (i = 0; i < entries->nr; i++) {
	struct stage_data *e = entries->items[i].util;
	if (!e->processed)
	BUG("unprocessed path??? %s",
	entries->items[i].string);
	}

	cleanup:
	final_cleanup_renames(&re_info);

	string_list_clear(entries, 1);
	free(entries);

	hashmap_clear_and_free(&opt->priv->current_file_dir_set,
	struct path_hashmap_entry, e);

	if (clean < 0) {
	unpack_trees_finish(opt);
	return clean;
	}
	}
	else
	clean = 1;

	unpack_trees_finish(opt);

	if (opt->priv->call_depth &&
	!(*result = write_in_core_index_as_tree(opt->repo)))
	return -1;

	return clean;
	}

	/*
	* Merge the commits h1 and h2, returning a flag (int) indicating the
	* cleanness of the merge. Also, if opt->priv->call_depth, create a
	* virtual commit and write its location to *result.
	*/
	static int merge_recursive_internal(struct merge_options *opt,
	struct commit *h1,
	struct commit *h2,
	struct commit_list *merge_bases,
	struct commit **result)
	{
	struct commit_list *iter;
	struct commit *merged_merge_bases;
	struct tree *result_tree;
	int clean;
	const char *ancestor_name;
	struct strbuf merge_base_abbrev = STRBUF_INIT;

	if (show(opt, 4)) {
	output(opt, 4, _("Merging:"));
	output_commit_title(opt, h1);
	output_commit_title(opt, h2);
	}

	if (!merge_bases) {
	merge_bases = get_merge_bases(h1, h2);
	merge_bases = reverse_commit_list(merge_bases);
	}

	if (show(opt, 5)) {
	unsigned cnt = commit_list_count(merge_bases);

	output(opt, 5, Q_("found %u common ancestor:",
	"found %u common ancestors:", cnt), cnt);
	for (iter = merge_bases; iter; iter = iter->next)
	output_commit_title(opt, iter->item);
	}

	merged_merge_bases = pop_commit(&merge_bases);
	if (merged_merge_bases == NULL) {
	/* if there is no common ancestor, use an empty tree */
	struct tree *tree;

	tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
	merged_merge_bases = make_virtual_commit(opt->repo, tree,
	"ancestor");
	ancestor_name = "empty tree";
	} else if (opt->ancestor && !opt->priv->call_depth) {
	ancestor_name = opt->ancestor;
	} else if (merge_bases) {
	ancestor_name = "merged common ancestors";
	} else {
	strbuf_add_unique_abbrev(&merge_base_abbrev,
	&merged_merge_bases->object.oid,
	DEFAULT_ABBREV);
	ancestor_name = merge_base_abbrev.buf;
	}

	for (iter = merge_bases; iter; iter = iter->next) {
	const char saved_b1, saved_b2;
	opt->priv->call_depth++;
	/*
	* When the merge fails, the result contains files
	* with conflict markers. The cleanness flag is
	* ignored (unless indicating an error), it was never
	* actually used, as result of merge_trees has always
	* overwritten it: the committed "conflicts" were
	* already resolved.
	*/
	discard_index(opt->repo->index);
	saved_b1 = opt->branch1;
	saved_b2 = opt->branch2;
	opt->branch1 = "Temporary merge branch 1";
	opt->branch2 = "Temporary merge branch 2";
	if (merge_recursive_internal(opt, merged_merge_bases, iter->item,
	NULL, &merged_merge_bases) < 0)
	return -1;
	opt->branch1 = saved_b1;
	opt->branch2 = saved_b2;
	opt->priv->call_depth--;

	if (!merged_merge_bases)
	return err(opt, _("merge returned no commit"));
	}

	/*
	* FIXME: Since merge_recursive_internal() is only ever called by
	* places that ensure the index is loaded first
	* (e.g. builtin/merge.c, rebase/sequencer, etc.), in the common
	* case where the merge base was unique that means when we get here
	* we immediately discard the index and re-read it, which is a
	* complete waste of time. We should only be discarding and
	* re-reading if we were forced to recurse.
	*/
	discard_index(opt->repo->index);
	if (!opt->priv->call_depth)
	repo_read_index(opt->repo);

	opt->ancestor = ancestor_name;
	clean = merge_trees_internal(opt,
	repo_get_commit_tree(opt->repo, h1),
	repo_get_commit_tree(opt->repo, h2),
	repo_get_commit_tree(opt->repo,
	merged_merge_bases),
	&result_tree);
	strbuf_release(&merge_base_abbrev);
	opt->ancestor = NULL; /* avoid accidental re-use of opt->ancestor */
	if (clean < 0) {
	flush_output(opt);
	return clean;
	}

	if (opt->priv->call_depth) {
	*result = make_virtual_commit(opt->repo, result_tree,
	"merged tree");
	commit_list_insert(h1, &(*result)->parents);
	commit_list_insert(h2, &(*result)->parents->next);
	}
	return clean;
	}

	static int merge_start(struct merge_options opt, struct tree head)
	{
	struct strbuf sb = STRBUF_INIT;

	/* Sanity checks on opt */
	assert(opt->repo);

	assert(opt->branch1 && opt->branch2);

	assert(opt->detect_renames >= -1 &&
	opt->detect_renames <= DIFF_DETECT_COPY);
	assert(opt->detect_directory_renames >= MERGE_DIRECTORY_RENAMES_NONE &&
	opt->detect_directory_renames <= MERGE_DIRECTORY_RENAMES_TRUE);
	assert(opt->rename_limit >= -1);
	assert(opt->rename_score >= 0 && opt->rename_score <= MAX_SCORE);
	assert(opt->show_rename_progress >= 0 && opt->show_rename_progress <= 1);

	assert(opt->xdl_opts >= 0);
	assert(opt->recursive_variant >= MERGE_VARIANT_NORMAL &&
	opt->recursive_variant <= MERGE_VARIANT_THEIRS);

	assert(opt->verbosity >= 0 && opt->verbosity <= 5);
	assert(opt->buffer_output <= 2);
	assert(opt->obuf.len == 0);

	assert(opt->priv == NULL);

	/* Sanity check on repo state; index must match head */
	if (repo_index_has_changes(opt->repo, head, &sb)) {
	err(opt, _("Your local changes to the following files would be overwritten by merge:\n %s"),
	sb.buf);
	strbuf_release(&sb);
	return -1;
	}

	CALLOC_ARRAY(opt->priv, 1);
	string_list_init(&opt->priv->df_conflict_file_set, 1);
	return 0;
	}

	static void merge_finalize(struct merge_options *opt)
	{
	flush_output(opt);
	if (!opt->priv->call_depth && opt->buffer_output < 2)
	strbuf_release(&opt->obuf);
	if (show(opt, 2))
	diff_warn_rename_limit("merge.renamelimit",
	opt->priv->needed_rename_limit, 0);
	FREE_AND_NULL(opt->priv);
	}

	int merge_trees(struct merge_options *opt,
	struct tree *head,
	struct tree *merge,
	struct tree *merge_base)
	{
	int clean;
	struct tree *ignored;

	assert(opt->ancestor != NULL);

	if (merge_start(opt, head))
	return -1;
	clean = merge_trees_internal(opt, head, merge, merge_base, &ignored);
	merge_finalize(opt);

	return clean;
	}

	int merge_recursive(struct merge_options *opt,
	struct commit *h1,
	struct commit *h2,
	struct commit_list *merge_bases,
	struct commit **result)
	{
	int clean;

	assert(opt->ancestor == NULL \|\|
	!strcmp(opt->ancestor, "constructed merge base"));

	if (merge_start(opt, repo_get_commit_tree(opt->repo, h1)))
	return -1;
	clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);
	merge_finalize(opt);

	return clean;
	}

	static struct commit get_ref(struct repository repo,
	const struct object_id *oid,
	const char *name)
	{
	struct object *object;

	object = deref_tag(repo, parse_object(repo, oid),
	name, strlen(name));
	if (!object)
	return NULL;
	if (object->type == OBJ_TREE)
	return make_virtual_commit(repo, (struct tree*)object, name);
	if (object->type != OBJ_COMMIT)
	return NULL;
	if (parse_commit((struct commit *)object))
	return NULL;
	return (struct commit *)object;
	}

	int merge_recursive_generic(struct merge_options *opt,
	const struct object_id *head,
	const struct object_id *merge,
	int num_merge_bases,
	const struct object_id **merge_bases,
	struct commit **result)
	{
	int clean;
	struct lock_file lock = LOCK_INIT;
	struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
	struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
	struct commit_list *ca = NULL;

	if (merge_bases) {
	int i;
	for (i = 0; i < num_merge_bases; ++i) {
	struct commit *base;
	if (!(base = get_ref(opt->repo, merge_bases[i],
	oid_to_hex(merge_bases[i]))))
	return err(opt, _("Could not parse object '%s'"),
	oid_to_hex(merge_bases[i]));
	commit_list_insert(base, &ca);
	}
	if (num_merge_bases == 1)
	opt->ancestor = "constructed merge base";
	}

	repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
	clean = merge_recursive(opt, head_commit, next_commit, ca,
	result);
	if (clean < 0) {
	rollback_lock_file(&lock);
	return clean;
	}

	if (write_locked_index(opt->repo->index, &lock,
	COMMIT_LOCK \| SKIP_IF_UNCHANGED))
	return err(opt, _("Unable to write index."));

	return clean ? 0 : 1;
	}

	static void merge_recursive_config(struct merge_options *opt)
	{
	char *value = NULL;
	int renormalize = 0;
	git_config_get_int("merge.verbosity", &opt->verbosity);
	git_config_get_int("diff.renamelimit", &opt->rename_limit);
	git_config_get_int("merge.renamelimit", &opt->rename_limit);
	git_config_get_bool("merge.renormalize", &renormalize);
	opt->renormalize = renormalize;
	if (!git_config_get_string("diff.renames", &value)) {
	opt->detect_renames = git_config_rename("diff.renames", value);
	free(value);
	}
	if (!git_config_get_string("merge.renames", &value)) {
	opt->detect_renames = git_config_rename("merge.renames", value);
	free(value);
	}
	if (!git_config_get_string("merge.directoryrenames", &value)) {
	int boolval = git_parse_maybe_bool(value);
	if (0 <= boolval) {
	opt->detect_directory_renames = boolval ?
	MERGE_DIRECTORY_RENAMES_TRUE :
	MERGE_DIRECTORY_RENAMES_NONE;
	} else if (!strcasecmp(value, "conflict")) {
	opt->detect_directory_renames =
	MERGE_DIRECTORY_RENAMES_CONFLICT;
	} /* avoid erroring on values from future versions of git */
	free(value);
	}
	git_config(git_xmerge_config, NULL);
	}

	void init_merge_options(struct merge_options *opt,
	struct repository *repo)
	{
	const char *merge_verbosity;
	memset(opt, 0, sizeof(struct merge_options));

	opt->repo = repo;

	opt->detect_renames = -1;
	opt->detect_directory_renames = MERGE_DIRECTORY_RENAMES_CONFLICT;
	opt->rename_limit = -1;

	opt->verbosity = 2;
	opt->buffer_output = 1;
	strbuf_init(&opt->obuf, 0);

	opt->renormalize = 0;

	merge_recursive_config(opt);
	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
	if (merge_verbosity)
	opt->verbosity = strtol(merge_verbosity, NULL, 10);
	if (opt->verbosity >= 5)
	opt->buffer_output = 0;
	}

	int parse_merge_opt(struct merge_options opt, const char s)
	{
	const char *arg;

	if (!s \|\| !*s)
	return -1;
	if (!strcmp(s, "ours"))
	opt->recursive_variant = MERGE_VARIANT_OURS;
	else if (!strcmp(s, "theirs"))
	opt->recursive_variant = MERGE_VARIANT_THEIRS;
	else if (!strcmp(s, "subtree"))
	opt->subtree_shift = "";
	else if (skip_prefix(s, "subtree=", &arg))
	opt->subtree_shift = arg;
	else if (!strcmp(s, "patience"))
	opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
	else if (!strcmp(s, "histogram"))
	opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
	long value = parse_algorithm_value(arg);
	if (value < 0)
	return -1;
	/* clear out previous settings */
	DIFF_XDL_CLR(opt, NEED_MINIMAL);
	opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
	opt->xdl_opts \|= value;
	}
	else if (!strcmp(s, "ignore-space-change"))
	DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
	else if (!strcmp(s, "ignore-all-space"))
	DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
	else if (!strcmp(s, "ignore-space-at-eol"))
	DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
	else if (!strcmp(s, "ignore-cr-at-eol"))
	DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
	else if (!strcmp(s, "renormalize"))
	opt->renormalize = 1;
	else if (!strcmp(s, "no-renormalize"))
	opt->renormalize = 0;
	else if (!strcmp(s, "no-renames"))
	opt->detect_renames = 0;
	else if (!strcmp(s, "find-renames")) {
	opt->detect_renames = 1;
	opt->rename_score = 0;
	}
	else if (skip_prefix(s, "find-renames=", &arg) \|\|
	skip_prefix(s, "rename-threshold=", &arg)) {
	if ((opt->rename_score = parse_rename_score(&arg)) == -1 \|\| *arg != 0)
	return -1;
	opt->detect_renames = 1;
	}
	/*
	* Please update $__git_merge_strategy_options in
	* git-completion.bash when you add new options
	*/
	else
	return -1;
	return 0;
	}

git / git

git/merge-recursive.c