Merge branch 'en/merge-directory-renames'

"git merge-recursive" backend recently learned a new heuristics to
infer file movement based on how other files in the same directory
moved.  As this is inherently less robust heuristics than the one
based on the content similarity of the file itself (rather than
based on what its neighbours are doing), it sometimes gives an
outcome unexpected by the end users.  This has been toned down to
leave the renamed paths in higher/conflicted stages in the index so
that the user can examine and confirm the result.

* en/merge-directory-renames:
  merge-recursive: switch directory rename detection default
  merge-recursive: give callers of handle_content_merge() access to contents
  merge-recursive: track information associated with directory renames
  t6043: fix copied test description to match its purpose
  merge-recursive: switch from (oid,mode) pairs to a diff_filespec
  merge-recursive: cleanup handle_rename_* function signatures
  merge-recursive: track branch where rename occurred in rename struct
  merge-recursive: remove ren[12]_other fields from rename_conflict_info
  merge-recursive: shrink rename_conflict_info
  merge-recursive: move some struct declarations together
  merge-recursive: use 'ci' for rename_conflict_info variable name
  merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
  merge-recursive: rename diff_filespec 'one' to 'o'
  merge-recursive: rename merge_options argument from 'o' to 'opt'
  Use 'unsigned short' for mode, like diff_filespec does

1 files changed, 915 insertions, 938 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index 6126773a7b..69abd6edec 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -115,32 +115,32 @@ static void collision_init(struct hashmap *map)
 	hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0);
 }
 
-static void flush_output(struct merge_options *o)
+static void flush_output(struct merge_options *opt)
 {
-	if (o->buffer_output < 2 && o->obuf.len) {
-		fputs(o->obuf.buf, stdout);
-		strbuf_reset(&o->obuf);
+	if (opt->buffer_output < 2 && opt->obuf.len) {
+		fputs(opt->obuf.buf, stdout);
+		strbuf_reset(&opt->obuf);
 	}
 }
 
-static int err(struct merge_options *o, const char *err, ...)
+static int err(struct merge_options *opt, const char *err, ...)
 {
 	va_list params;
 
-	if (o->buffer_output < 2)
-		flush_output(o);
+	if (opt->buffer_output < 2)
+		flush_output(opt);
 	else {
-		strbuf_complete(&o->obuf, '\n');
-		strbuf_addstr(&o->obuf, "error: ");
+		strbuf_complete(&opt->obuf, '\n');
+		strbuf_addstr(&opt->obuf, "error: ");
 	}
 	va_start(params, err);
-	strbuf_vaddf(&o->obuf, err, params);
+	strbuf_vaddf(&opt->obuf, err, params);
 	va_end(params);
-	if (o->buffer_output > 1)
-		strbuf_addch(&o->obuf, '\n');
+	if (opt->buffer_output > 1)
+		strbuf_addch(&opt->obuf, '\n');
 	else {
-		error("%s", o->obuf.buf);
-		strbuf_reset(&o->obuf);
+		error("%s", opt->obuf.buf);
+		strbuf_reset(&opt->obuf);
 	}
 
 	return -1;
@@ -196,163 +196,148 @@ enum rename_type {
 	RENAME_TWO_FILES_TO_ONE
 };
 
-struct rename_conflict_info {
-	enum rename_type rename_type;
-	struct diff_filepair *pair1;
-	struct diff_filepair *pair2;
-	const char *branch1;
-	const char *branch2;
-	struct stage_data *dst_entry1;
-	struct stage_data *dst_entry2;
-	struct diff_filespec ren1_other;
-	struct diff_filespec ren2_other;
-};
-
 /*
  * Since we want to write the index eventually, we cannot reuse the index
  * for these (temporary) data.
  */
 struct stage_data {
-	struct {
-		unsigned mode;
-		struct object_id oid;
-	} stages[4];
+	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 diff_filepair *pair1,
-					      struct diff_filepair *pair2,
-					      const char *branch1,
-					      const char *branch2,
-					      struct stage_data *dst_entry1,
-					      struct stage_data *dst_entry2,
-					      struct merge_options *o,
-					      struct stage_data *src_entry1,
-					      struct stage_data *src_entry2)
-{
-	int ostage1 = 0, ostage2;
+					      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 == o->branch1.  So, simply flip arguments
+	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
 	 * around if we don't have that.
 	 */
-	if (dst_entry2 && branch1 != o->branch1) {
-		setup_rename_conflict_info(rename_type,
-					   pair2,      pair1,
-					   branch2,    branch1,
-					   dst_entry2, dst_entry1,
-					   o,
-					   src_entry2, src_entry1);
+	if (ren2 && ren1->branch != opt->branch1) {
+		setup_rename_conflict_info(rename_type, opt, ren2, ren1);
 		return;
 	}
 
 	ci = xcalloc(1, sizeof(struct rename_conflict_info));
 	ci->rename_type = rename_type;
-	ci->pair1 = pair1;
-	ci->branch1 = branch1;
-	ci->branch2 = branch2;
+	ci->ren1 = ren1;
+	ci->ren2 = ren2;
 
-	ci->dst_entry1 = dst_entry1;
-	dst_entry1->rename_conflict_info = ci;
-	dst_entry1->processed = 0;
-
-	assert(!pair2 == !dst_entry2);
-	if (dst_entry2) {
-		ci->dst_entry2 = dst_entry2;
-		ci->pair2 = pair2;
-		dst_entry2->rename_conflict_info = ci;
-	}
-
-	/*
-	 * For each rename, there could have been
-	 * modifications on the side of history where that
-	 * file was not renamed.
-	 */
-	if (rename_type == RENAME_ADD ||
-	    rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage1 = o->branch1 == branch1 ? 3 : 2;
-
-		ci->ren1_other.path = pair1->one->path;
-		oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
-		ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
-	}
-
-	if (rename_type == RENAME_TWO_FILES_TO_ONE) {
-		ostage2 = ostage1 ^ 1;
-
-		ci->ren2_other.path = pair2->one->path;
-		oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
-		ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
+	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 *o, int v)
+static int show(struct merge_options *opt, int v)
 {
-	return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
+	return (!opt->call_depth && opt->verbosity >= v) || opt->verbosity >= 5;
 }
 
 __attribute__((format (printf, 3, 4)))
-static void output(struct merge_options *o, int v, const char *fmt, ...)
+static void output(struct merge_options *opt, int v, const char *fmt, ...)
 {
 	va_list ap;
 
-	if (!show(o, v))
+	if (!show(opt, v))
 		return;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 
 	va_start(ap, fmt);
-	strbuf_vaddf(&o->obuf, fmt, ap);
+	strbuf_vaddf(&opt->obuf, fmt, ap);
 	va_end(ap);
 
-	strbuf_addch(&o->obuf, '\n');
-	if (!o->buffer_output)
-		flush_output(o);
+	strbuf_addch(&opt->obuf, '\n');
+	if (!opt->buffer_output)
+		flush_output(opt);
 }
 
-static void output_commit_title(struct merge_options *o, struct commit *commit)
+static void output_commit_title(struct merge_options *opt, struct commit *commit)
 {
 	struct merge_remote_desc *desc;
 
-	strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
+	strbuf_addchars(&opt->obuf, ' ', opt->call_depth * 2);
 	desc = merge_remote_util(commit);
 	if (desc)
-		strbuf_addf(&o->obuf, "virtual %s\n", desc->name);
+		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
 	else {
-		strbuf_add_unique_abbrev(&o->obuf, &commit->object.oid,
+		strbuf_add_unique_abbrev(&opt->obuf, &commit->object.oid,
 					 DEFAULT_ABBREV);
-		strbuf_addch(&o->obuf, ' ');
+		strbuf_addch(&opt->obuf, ' ');
 		if (parse_commit(commit) != 0)
-			strbuf_addstr(&o->obuf, _("(bad commit)\n"));
+			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(&o->obuf, "%.*s\n", len, title);
+				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
 			unuse_commit_buffer(commit, msg);
 		}
 	}
-	flush_output(o);
+	flush_output(opt);
 }
 
-static int add_cacheinfo(struct merge_options *o,
-			 unsigned int mode, const struct object_id *oid,
+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 = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	struct cache_entry *ce;
 	int ret;
 
-	ce = make_cache_entry(istate, mode, oid ? oid : &null_oid, path, stage, 0);
+	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
 	if (!ce)
-		return err(o, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
+		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
 
 	ret = add_index_entry(istate, ce, options);
 	if (refresh) {
@@ -361,7 +346,7 @@ static int add_cacheinfo(struct merge_options *o,
 		nce = refresh_cache_entry(istate, ce,
 					  CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 		if (!nce)
-			return err(o, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
+			return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
 		if (nce != ce)
 			ret = add_index_entry(istate, nce, options);
 	}
@@ -374,7 +359,7 @@ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 	init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int unpack_trees_start(struct merge_options *o,
+static int unpack_trees_start(struct merge_options *opt,
 			      struct tree *common,
 			      struct tree *head,
 			      struct tree *merge)
@@ -383,49 +368,49 @@ static int unpack_trees_start(struct merge_options *o,
 	struct tree_desc t[3];
 	struct index_state tmp_index = { NULL };
 
-	memset(&o->unpack_opts, 0, sizeof(o->unpack_opts));
-	if (o->call_depth)
-		o->unpack_opts.index_only = 1;
+	memset(&opt->unpack_opts, 0, sizeof(opt->unpack_opts));
+	if (opt->call_depth)
+		opt->unpack_opts.index_only = 1;
 	else
-		o->unpack_opts.update = 1;
-	o->unpack_opts.merge = 1;
-	o->unpack_opts.head_idx = 2;
-	o->unpack_opts.fn = threeway_merge;
-	o->unpack_opts.src_index = o->repo->index;
-	o->unpack_opts.dst_index = &tmp_index;
-	o->unpack_opts.aggressive = !merge_detect_rename(o);
-	setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
+		opt->unpack_opts.update = 1;
+	opt->unpack_opts.merge = 1;
+	opt->unpack_opts.head_idx = 2;
+	opt->unpack_opts.fn = threeway_merge;
+	opt->unpack_opts.src_index = opt->repo->index;
+	opt->unpack_opts.dst_index = &tmp_index;
+	opt->unpack_opts.aggressive = !merge_detect_rename(opt);
+	setup_unpack_trees_porcelain(&opt->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, &o->unpack_opts);
-	cache_tree_free(&o->repo->index->cache_tree);
+	rc = unpack_trees(3, t, &opt->unpack_opts);
+	cache_tree_free(&opt->repo->index->cache_tree);
 
 	/*
-	 * Update o->repo->index to match the new results, AFTER saving a copy
-	 * in o->orig_index.  Update src_index to point to the saved copy.
+	 * Update opt->repo->index to match the new results, AFTER saving a copy
+	 * in opt->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.)
 	 */
-	o->orig_index = *o->repo->index;
-	*o->repo->index = tmp_index;
-	o->unpack_opts.src_index = &o->orig_index;
+	opt->orig_index = *opt->repo->index;
+	*opt->repo->index = tmp_index;
+	opt->unpack_opts.src_index = &opt->orig_index;
 
 	return rc;
 }
 
-static void unpack_trees_finish(struct merge_options *o)
+static void unpack_trees_finish(struct merge_options *opt)
 {
-	discard_index(&o->orig_index);
-	clear_unpack_trees_porcelain(&o->unpack_opts);
+	discard_index(&opt->orig_index);
+	clear_unpack_trees_porcelain(&opt->unpack_opts);
 }
 
-struct tree *write_tree_from_memory(struct merge_options *o)
+struct tree *write_tree_from_memory(struct merge_options *opt)
 {
 	struct tree *result = NULL;
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	if (unmerged_index(istate)) {
 		int i;
@@ -444,11 +429,11 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 
 	if (!cache_tree_fully_valid(istate->cache_tree) &&
 	    cache_tree_update(istate, 0) < 0) {
-		err(o, _("error building trees"));
+		err(opt, _("error building trees"));
 		return NULL;
 	}
 
-	result = lookup_tree(o->repo, &istate->cache_tree->oid);
+	result = lookup_tree(opt->repo, &istate->cache_tree->oid);
 
 	return result;
 }
@@ -459,37 +444,36 @@ static int save_files_dirs(const struct object_id *oid,
 {
 	struct path_hashmap_entry *entry;
 	int baselen = base->len;
-	struct merge_options *o = context;
+	struct merge_options *opt = context;
 
 	strbuf_addstr(base, path);
 
 	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 	hashmap_entry_init(entry, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 
 	strbuf_setlen(base, baselen);
 	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 }
 
-static void get_files_dirs(struct merge_options *o, struct tree *tree)
+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_recursive(the_repository, tree, "", 0, 0,
-			    &match_all, save_files_dirs, o);
+			    &match_all, save_files_dirs, opt);
 }
 
 static int get_tree_entry_if_blob(const struct object_id *tree,
 				  const char *path,
-				  struct object_id *hashy,
-				  unsigned int *mode_o)
+				  struct diff_filespec *dfs)
 {
 	int ret;
 
-	ret = get_tree_entry(tree, path, hashy, mode_o);
-	if (S_ISDIR(*mode_o)) {
-		oidcpy(hashy, &null_oid);
-		*mode_o = 0;
+	ret = get_tree_entry(tree, path, &dfs->oid, &dfs->mode);
+	if (S_ISDIR(dfs->mode)) {
+		oidcpy(&dfs->oid, &null_oid);
+		dfs->mode = 0;
 	}
 	return ret;
 }
@@ -504,12 +488,9 @@ static struct stage_data *insert_stage_data(const char *path,
 {
 	struct string_list_item *item;
 	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-	get_tree_entry_if_blob(&o->object.oid, path,
-			       &e->stages[1].oid, &e->stages[1].mode);
-	get_tree_entry_if_blob(&a->object.oid, path,
-			       &e->stages[2].oid, &e->stages[2].mode);
-	get_tree_entry_if_blob(&b->object.oid, path,
-			       &e->stages[3].oid, &e->stages[3].mode);
+	get_tree_entry_if_blob(&o->object.oid, path, &e->stages[1]);
+	get_tree_entry_if_blob(&a->object.oid, path, &e->stages[2]);
+	get_tree_entry_if_blob(&b->object.oid, path, &e->stages[3]);
 	item = string_list_insert(entries, path);
 	item->util = e;
 	return e;
@@ -573,7 +554,7 @@ static int string_list_df_name_compare(const char *one, const char *two)
 	return onelen - twolen;
 }
 
-static void record_df_conflict_files(struct merge_options *o,
+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
@@ -598,7 +579,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	 * If we're merging merge-bases, we don't want to bother with
 	 * any working directory changes.
 	 */
-	if (o->call_depth)
+	if (opt->call_depth)
 		return;
 
 	/* Ensure D/F conflicts are adjacent in the entries list. */
@@ -610,7 +591,7 @@ static void record_df_conflict_files(struct merge_options *o,
 	df_sorted_entries.cmp = string_list_df_name_compare;
 	string_list_sort(&df_sorted_entries);
 
-	string_list_clear(&o->df_conflict_file_set, 1);
+	string_list_clear(&opt->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);
@@ -626,7 +607,7 @@ static void record_df_conflict_files(struct merge_options *o,
 		    len > last_len &&
 		    memcmp(path, last_file, last_len) == 0 &&
 		    path[last_len] == '/') {
-			string_list_insert(&o->df_conflict_file_set, last_file);
+			string_list_insert(&opt->df_conflict_file_set, last_file);
 		}
 
 		/*
@@ -645,33 +626,6 @@ static void record_df_conflict_files(struct merge_options *o,
 	string_list_clear(&df_sorted_entries, 0);
 }
 
-struct rename {
-	struct diff_filepair *pair;
-	/*
-	 * 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;
-	unsigned add_turned_into_rename:1;
-	unsigned processed:1;
-};
-
 static int update_stages(struct merge_options *opt, const char *path,
 			 const struct diff_filespec *o,
 			 const struct diff_filespec *a,
@@ -692,13 +646,13 @@ static int update_stages(struct merge_options *opt, const char *path,
 		if (remove_file_from_index(opt->repo->index, path))
 			return -1;
 	if (o)
-		if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
+		if (add_cacheinfo(opt, o, path, 1, 0, options))
 			return -1;
 	if (a)
-		if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
+		if (add_cacheinfo(opt, a, path, 2, 0, options))
 			return -1;
 	if (b)
-		if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
+		if (add_cacheinfo(opt, b, path, 3, 0, options))
 			return -1;
 	return 0;
 }
@@ -717,20 +671,20 @@ static void update_entry(struct stage_data *entry,
 	oidcpy(&entry->stages[3].oid, &b->oid);
 }
 
-static int remove_file(struct merge_options *o, int clean,
+static int remove_file(struct merge_options *opt, int clean,
 		       const char *path, int no_wd)
 {
-	int update_cache = o->call_depth || clean;
-	int update_working_directory = !o->call_depth && !no_wd;
+	int update_cache = opt->call_depth || clean;
+	int update_working_directory = !opt->call_depth && !no_wd;
 
 	if (update_cache) {
-		if (remove_file_from_index(o->repo->index, path))
+		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(o->repo->index, path, strlen(path),
+			ce = index_file_exists(opt->repo->index, path, strlen(path),
 					       ignore_case);
 			if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
 				return 0;
@@ -751,7 +705,7 @@ static void add_flattened_path(struct strbuf *out, const char *s)
 			out->buf[i] = '_';
 }
 
-static char *unique_path(struct merge_options *o, const char *path, const char *branch)
+static char *unique_path(struct merge_options *opt, const char *path, const char *branch)
 {
 	struct path_hashmap_entry *entry;
 	struct strbuf newpath = STRBUF_INIT;
@@ -762,16 +716,16 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
 	add_flattened_path(&newpath, branch);
 
 	base_len = newpath.len;
-	while (hashmap_get_from_hash(&o->current_file_dir_set,
+	while (hashmap_get_from_hash(&opt->current_file_dir_set,
 				     path_hash(newpath.buf), newpath.buf) ||
-	       (!o->call_depth && file_exists(newpath.buf))) {
+	       (!opt->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, path_hash(entry->path));
-	hashmap_add(&o->current_file_dir_set, entry);
+	hashmap_add(&opt->current_file_dir_set, entry);
 	return strbuf_detach(&newpath, NULL);
 }
 
@@ -810,10 +764,10 @@ static int dir_in_way(struct index_state *istate, const char *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 *o, const char *path,
-				   const struct object_id *oid, unsigned mode)
+static int was_tracked_and_matches(struct merge_options *opt, const char *path,
+				   const struct diff_filespec *blob)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 	struct cache_entry *ce;
 
 	if (0 > pos)
@@ -821,16 +775,16 @@ static int was_tracked_and_matches(struct merge_options *o, const char *path,
 		return 0;
 
 	/* See if the file we were tracking before matches */
-	ce = o->orig_index.cache[pos];
-	return (oid_eq(&ce->oid, oid) && ce->ce_mode == mode);
+	ce = opt->orig_index.cache[pos];
+	return (oid_eq(&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 *o, const char *path)
+static int was_tracked(struct merge_options *opt, const char *path)
 {
-	int pos = index_name_pos(&o->orig_index, path, strlen(path));
+	int pos = index_name_pos(&opt->orig_index, path, strlen(path));
 
 	if (0 <= pos)
 		/* we were tracking this path before the merge */
@@ -839,13 +793,13 @@ static int was_tracked(struct merge_options *o, const char *path)
 	return 0;
 }
 
-static int would_lose_untracked(struct merge_options *o, const char *path)
+static int would_lose_untracked(struct merge_options *opt, const char *path)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 
 	/*
 	 * This may look like it can be simplified to:
-	 *   return !was_tracked(o, path) && file_exists(path)
+	 *   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
@@ -882,38 +836,38 @@ static int would_lose_untracked(struct merge_options *o, const char *path)
 	return file_exists(path);
 }
 
-static int was_dirty(struct merge_options *o, const char *path)
+static int was_dirty(struct merge_options *opt, const char *path)
 {
 	struct cache_entry *ce;
 	int dirty = 1;
 
-	if (o->call_depth || !was_tracked(o, path))
+	if (opt->call_depth || !was_tracked(opt, path))
 		return !dirty;
 
-	ce = index_file_exists(o->unpack_opts.src_index,
+	ce = index_file_exists(opt->unpack_opts.src_index,
 			       path, strlen(path), ignore_case);
-	dirty = verify_uptodate(ce, &o->unpack_opts) != 0;
+	dirty = verify_uptodate(ce, &opt->unpack_opts) != 0;
 	return dirty;
 }
 
-static int make_room_for_path(struct merge_options *o, const char *path)
+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 < o->df_conflict_file_set.nr; i++) {
-		const char *df_path = o->df_conflict_file_set.items[i].string;
+	for (i = 0; i < opt->df_conflict_file_set.nr; i++) {
+		const char *df_path = opt->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(o, 3,
+			output(opt, 3,
 			       _("Removing %s to make room for subdirectory\n"),
 			       df_path);
 			unlink(df_path);
-			unsorted_string_list_delete_item(&o->df_conflict_file_set,
+			unsorted_string_list_delete_item(&opt->df_conflict_file_set,
 							 i, 0);
 			break;
 		}
@@ -924,16 +878,16 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (status) {
 		if (status == SCLD_EXISTS)
 			/* something else exists */
-			return err(o, msg, path, _(": perhaps a D/F conflict?"));
-		return err(o, msg, path, "");
+			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(o, path))
-		return err(o, _("refusing to lose untracked file at '%s'"),
+	if (would_lose_untracked(opt, path))
+		return err(opt, _("refusing to lose untracked file at '%s'"),
 			   path);
 
 	/* Successful unlink is good.. */
@@ -943,19 +897,18 @@ static int make_room_for_path(struct merge_options *o, const char *path)
 	if (errno == ENOENT)
 		return 0;
 	/* .. but not some other error (who really cares what?) */
-	return err(o, msg, path, _(": perhaps a D/F conflict?"));
+	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
 }
 
-static int update_file_flags(struct merge_options *o,
-			     const struct object_id *oid,
-			     unsigned mode,
+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 (o->call_depth)
+	if (opt->call_depth)
 		update_wd = 0;
 
 	if (update_wd) {
@@ -963,7 +916,7 @@ static int update_file_flags(struct merge_options *o,
 		void *buf;
 		unsigned long size;
 
-		if (S_ISGITLINK(mode)) {
+		if (S_ISGITLINK(contents->mode)) {
 			/*
 			 * We may later decide to recursively descend into
 			 * the submodule directory and update its index
@@ -973,84 +926,84 @@ static int update_file_flags(struct merge_options *o,
 			goto update_index;
 		}
 
-		buf = read_object_file(oid, &type, &size);
+		buf = read_object_file(&contents->oid, &type, &size);
 		if (!buf)
-			return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
+			return err(opt, _("cannot read object %s '%s'"),
+				   oid_to_hex(&contents->oid), path);
 		if (type != OBJ_BLOB) {
-			ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
+			ret = err(opt, _("blob expected for %s '%s'"),
+				  oid_to_hex(&contents->oid), path);
 			goto free_buf;
 		}
-		if (S_ISREG(mode)) {
+		if (S_ISREG(contents->mode)) {
 			struct strbuf strbuf = STRBUF_INIT;
-			if (convert_to_working_tree(o->repo->index, path, buf, size, &strbuf)) {
+			if (convert_to_working_tree(opt->repo->index, path, buf, size, &strbuf)) {
 				free(buf);
 				size = strbuf.len;
 				buf = strbuf_detach(&strbuf, NULL);
 			}
 		}
 
-		if (make_room_for_path(o, path) < 0) {
+		if (make_room_for_path(opt, path) < 0) {
 			update_wd = 0;
 			goto free_buf;
 		}
-		if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
+		if (S_ISREG(contents->mode) ||
+		    (!has_symlinks && S_ISLNK(contents->mode))) {
 			int fd;
-			if (mode & 0100)
-				mode = 0777;
-			else
-				mode = 0666;
+			int mode = (contents->mode & 0100 ? 0777 : 0666);
+
 			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 			if (fd < 0) {
-				ret = err(o, _("failed to open '%s': %s"),
+				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(mode)) {
+		} 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(o, _("failed to symlink '%s': %s"),
+				ret = err(opt, _("failed to symlink '%s': %s"),
 					  path, strerror(errno));
 			free(lnk);
 		} else
-			ret = err(o,
+			ret = err(opt,
 				  _("do not know what to do with %06o %s '%s'"),
-				  mode, oid_to_hex(oid), path);
+				  contents->mode, oid_to_hex(&contents->oid), path);
 	free_buf:
 		free(buf);
 	}
 update_index:
 	if (!ret && update_cache)
-		if (add_cacheinfo(o, mode, oid, path, 0, update_wd,
+		if (add_cacheinfo(opt, contents, path, 0, update_wd,
 				  ADD_CACHE_OK_TO_ADD))
 			return -1;
 	return ret;
 }
 
-static int update_file(struct merge_options *o,
+static int update_file(struct merge_options *opt,
 		       int clean,
-		       const struct object_id *oid,
-		       unsigned mode,
+		       const struct diff_filespec *contents,
 		       const char *path)
 {
-	return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
+	return update_file_flags(opt, contents, path,
+				 opt->call_depth || clean, !opt->call_depth);
 }
 
 /* Low level file merging, update and removal */
 
 struct merge_file_info {
-	struct object_id oid;
-	unsigned mode;
+	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
 	unsigned clean:1,
 		 merge:1;
 };
 
-static int merge_3way(struct merge_options *o,
+static int merge_3way(struct merge_options *opt,
 		      mmbuffer_t *result_buf,
-		      const struct diff_filespec *one,
+		      const struct diff_filespec *o,
 		      const struct diff_filespec *a,
 		      const struct diff_filespec *b,
 		      const char *branch1,
@@ -1062,15 +1015,15 @@ static int merge_3way(struct merge_options *o,
 	char *base_name, *name1, *name2;
 	int merge_status;
 
-	ll_opts.renormalize = o->renormalize;
+	ll_opts.renormalize = opt->renormalize;
 	ll_opts.extra_marker_size = extra_marker_size;
-	ll_opts.xdl_opts = o->xdl_opts;
+	ll_opts.xdl_opts = opt->xdl_opts;
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		ll_opts.virtual_ancestor = 1;
 		ll_opts.variant = 0;
 	} else {
-		switch (o->recursive_variant) {
+		switch (opt->recursive_variant) {
 		case MERGE_RECURSIVE_OURS:
 			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 			break;
@@ -1083,26 +1036,27 @@ static int merge_3way(struct merge_options *o,
 		}
 	}
 
+	assert(a->path && b->path);
 	if (strcmp(a->path, b->path) ||
-	    (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s:%s", o->ancestor, one->path);
+	    (opt->ancestor != NULL && strcmp(a->path, o->path) != 0)) {
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s:%s", opt->ancestor, o->path);
 		name1 = mkpathdup("%s:%s", branch1, a->path);
 		name2 = mkpathdup("%s:%s", branch2, b->path);
 	} else {
-		base_name = o->ancestor == NULL ? NULL :
-			mkpathdup("%s", o->ancestor);
+		base_name = opt->ancestor == NULL ? NULL :
+			mkpathdup("%s", opt->ancestor);
 		name1 = mkpathdup("%s", branch1);
 		name2 = mkpathdup("%s", branch2);
 	}
 
-	read_mmblob(&orig, &one->oid);
+	read_mmblob(&orig, &o->oid);
 	read_mmblob(&src1, &a->oid);
 	read_mmblob(&src2, &b->oid);
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
-				o->repo->index, &ll_opts);
+				opt->repo->index, &ll_opts);
 
 	free(base_name);
 	free(name1);
@@ -1184,7 +1138,12 @@ static void print_commit(struct commit *commit)
 	strbuf_release(&sb);
 }
 
-static int merge_submodule(struct merge_options *o,
+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)
@@ -1194,7 +1153,7 @@ static int merge_submodule(struct merge_options *o,
 	struct object_array merges;
 
 	int i;
-	int search = !o->call_depth;
+	int search = !opt->call_depth;
 
 	/* store a in result in case we fail */
 	oidcpy(result, a);
@@ -1208,32 +1167,32 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	if (add_submodule_odb(path)) {
-		output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
 		return 0;
 	}
 
-	if (!(commit_base = lookup_commit_reference(o->repo, base)) ||
-	    !(commit_a = lookup_commit_reference(o->repo, a)) ||
-	    !(commit_b = lookup_commit_reference(o->repo, b))) {
-		output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+	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(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+		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(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_b);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		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 */
 
@@ -1241,11 +1200,11 @@ static int merge_submodule(struct merge_options *o,
 	}
 	if (in_merge_bases(commit_b, commit_a)) {
 		oidcpy(result, a);
-		if (show(o, 3)) {
-			output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			output_commit_title(o, commit_a);
-		} else if (show(o, 2))
-			output(o, 2, _("Fast-forwarding submodule %s"), path);
+		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 */
 
@@ -1264,18 +1223,18 @@ static int merge_submodule(struct merge_options *o,
 		return 0;
 
 	/* find commit which merges them */
-	parent_count = find_first_merges(o->repo, &merges, path,
+	parent_count = find_first_merges(opt->repo, &merges, path,
 					 commit_a, commit_b);
 	switch (parent_count) {
 	case 0:
-		output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
 		break;
 
 	case 1:
-		output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
-		output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+		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(o, 2, _(
+		output(opt, 2, _(
 		       "If this is correct simply add it to the index "
 		       "for example\n"
 		       "by using:\n\n"
@@ -1285,7 +1244,7 @@ static int merge_submodule(struct merge_options *o,
 		break;
 
 	default:
-		output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+		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);
 	}
@@ -1294,8 +1253,8 @@ static int merge_submodule(struct merge_options *o,
 	return 0;
 }
 
-static int merge_mode_and_contents(struct merge_options *o,
-				   const struct diff_filespec *one,
+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,
@@ -1304,13 +1263,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 				   const int extra_marker_size,
 				   struct merge_file_info *result)
 {
-	if (o->branch1 != branch1) {
+	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(o, one, b, a,
+		return merge_mode_and_contents(opt, o, b, a,
 					       filename,
 					       branch2, branch1,
 					       extra_marker_size, result);
@@ -1322,48 +1281,48 @@ static int merge_mode_and_contents(struct merge_options *o,
 	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 		result->clean = 0;
 		if (S_ISREG(a->mode)) {
-			result->mode = a->mode;
-			oidcpy(&result->oid, &a->oid);
+			result->blob.mode = a->mode;
+			oidcpy(&result->blob.oid, &a->oid);
 		} else {
-			result->mode = b->mode;
-			oidcpy(&result->oid, &b->oid);
+			result->blob.mode = b->mode;
+			oidcpy(&result->blob.oid, &b->oid);
 		}
 	} else {
-		if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
+		if (!oid_eq(&a->oid, &o->oid) && !oid_eq(&b->oid, &o->oid))
 			result->merge = 1;
 
 		/*
 		 * Merge modes
 		 */
-		if (a->mode == b->mode || a->mode == one->mode)
-			result->mode = b->mode;
+		if (a->mode == b->mode || a->mode == o->mode)
+			result->blob.mode = b->mode;
 		else {
-			result->mode = a->mode;
-			if (b->mode != one->mode) {
+			result->blob.mode = a->mode;
+			if (b->mode != o->mode) {
 				result->clean = 0;
 				result->merge = 1;
 			}
 		}
 
-		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
-			oidcpy(&result->oid, &b->oid);
-		else if (oid_eq(&b->oid, &one->oid))
-			oidcpy(&result->oid, &a->oid);
+		if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &o->oid))
+			oidcpy(&result->blob.oid, &b->oid);
+		else if (oid_eq(&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(o, &result_buf, one, a, b,
+			merge_status = merge_3way(opt, &result_buf, o, a, b,
 						  branch1, branch2,
 						  extra_marker_size);
 
 			if ((merge_status < 0) || !result_buf.ptr)
-				ret = err(o, _("Failed to execute internal merge"));
+				ret = err(opt, _("Failed to execute internal merge"));
 
 			if (!ret &&
 			    write_object_file(result_buf.ptr, result_buf.size,
-					      blob_type, &result->oid))
-				ret = err(o, _("Unable to add %s to database"),
+					      blob_type, &result->blob.oid))
+				ret = err(opt, _("Unable to add %s to database"),
 					  a->path);
 
 			free(result_buf.ptr);
@@ -1371,23 +1330,23 @@ static int merge_mode_and_contents(struct merge_options *o,
 				return ret;
 			result->clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result->clean = merge_submodule(o, &result->oid,
-							one->path,
-							&one->oid,
+			result->clean = merge_submodule(opt, &result->blob.oid,
+							o->path,
+							&o->oid,
 							&a->oid,
 							&b->oid);
 		} else if (S_ISLNK(a->mode)) {
-			switch (o->recursive_variant) {
+			switch (opt->recursive_variant) {
 			case MERGE_RECURSIVE_NORMAL:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				if (!oid_eq(&a->oid, &b->oid))
 					result->clean = 0;
 				break;
 			case MERGE_RECURSIVE_OURS:
-				oidcpy(&result->oid, &a->oid);
+				oidcpy(&result->blob.oid, &a->oid);
 				break;
 			case MERGE_RECURSIVE_THEIRS:
-				oidcpy(&result->oid, &b->oid);
+				oidcpy(&result->blob.oid, &b->oid);
 				break;
 			}
 		} else
@@ -1395,14 +1354,13 @@ static int merge_mode_and_contents(struct merge_options *o,
 	}
 
 	if (result->merge)
-		output(o, 2, _("Auto-merging %s"), filename);
+		output(opt, 2, _("Auto-merging %s"), filename);
 
 	return 0;
 }
 
-static int handle_rename_via_dir(struct merge_options *o,
-				 struct diff_filepair *pair,
-				 const char *rename_branch)
+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
@@ -1410,38 +1368,47 @@ static int handle_rename_via_dir(struct merge_options *o,
 	 * there is no content merge to do; just move the file into the
 	 * desired final location.
 	 */
-	const struct diff_filespec *dest = pair->two;
+	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 == 1);
+	assert(ren->dir_rename_original_dest);
 
-	if (!o->call_depth && would_lose_untracked(o, dest->path)) {
-		char *alt_path = unique_path(o, dest->path, rename_branch);
+	if (!opt->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);
+	}
 
-		output(o, 1, _("Error: Refusing to lose untracked file at %s; "
-			       "writing to %s instead."),
-		       dest->path, alt_path);
+	if (mark_conflicted) {
 		/*
-		 * Write the file in worktree at alt_path, but not in the
-		 * index.  Instead, write to dest->path for the index but
-		 * only at the higher appropriate stage.
+		 * 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(o, 0, &dest->oid, dest->mode, alt_path))
+		if (update_file(opt, 0, dest, file_path))
 			return -1;
-		free(alt_path);
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		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 */
 	}
-
-	/* Update dest->path both in index and in worktree */
-	if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
-		return -1;
-	return 0;
 }
 
-static int handle_change_delete(struct merge_options *o,
+static int handle_change_delete(struct merge_options *opt,
 				const char *path, const char *old_path,
-				const struct object_id *o_oid, int o_mode,
-				const struct object_id *changed_oid,
-				int changed_mode,
+				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)
@@ -1450,20 +1417,20 @@ static int handle_change_delete(struct merge_options *o,
 	const char *update_path = path;
 	int ret = 0;
 
-	if (dir_in_way(o->repo->index, path, !o->call_depth, 0) ||
-	    (!o->call_depth && would_lose_untracked(o, path))) {
-		update_path = alt_path = unique_path(o, path, change_branch);
+	if (dir_in_way(opt->repo->index, path, !opt->call_depth, 0) ||
+	    (!opt->call_depth && would_lose_untracked(opt, path))) {
+		update_path = alt_path = unique_path(opt, path, change_branch);
 	}
 
-	if (o->call_depth) {
+	if (opt->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(o->repo->index, path);
+		ret = remove_file_from_index(opt->repo->index, path);
 		if (!ret)
-			ret = update_file(o, 0, o_oid, o_mode, update_path);
+			ret = update_file(opt, 0, o, update_path);
 	} else {
 		/*
 		 * Despite the four nearly duplicate messages and argument
@@ -1482,24 +1449,24 @@ static int handle_change_delete(struct merge_options *o,
 		 */
 		if (!alt_path) {
 			if (!old_path) {
-				output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				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(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				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(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				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(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
+				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);
@@ -1507,142 +1474,127 @@ static int handle_change_delete(struct merge_options *o,
 		}
 		/*
 		 * No need to call update_file() on path when change_branch ==
-		 * o->branch1 && !alt_path, since that would needlessly touch
+		 * 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 != o->branch1 || alt_path)
-			ret = update_file(o, 0, changed_oid, changed_mode, update_path);
+		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 *o,
-				struct diff_filepair *pair,
-				const char *rename_branch,
-				const char *delete_branch)
+static int handle_rename_delete(struct merge_options *opt,
+				struct rename_conflict_info *ci)
 {
-	const struct diff_filespec *orig = pair->one;
-	const struct diff_filespec *dest = pair->two;
-
-	if (handle_change_delete(o,
-				 o->call_depth ? orig->path : dest->path,
-				 o->call_depth ? NULL : orig->path,
-				 &orig->oid, orig->mode,
-				 &dest->oid, dest->mode,
+	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->call_depth ? orig->path : dest->path,
+				 opt->call_depth ? NULL : orig->path,
+				 orig, dest,
 				 rename_branch, delete_branch,
 				 _("rename"), _("renamed")))
 		return -1;
 
-	if (o->call_depth)
-		return remove_file_from_index(o->repo->index, dest->path);
+	if (opt->call_depth)
+		return remove_file_from_index(opt->repo->index, dest->path);
 	else
-		return update_stages(o, dest->path, NULL,
-				     rename_branch == o->branch1 ? dest : NULL,
-				     rename_branch == o->branch1 ? NULL : dest);
+		return update_stages(opt, dest->path, NULL,
+				     rename_branch == opt->branch1 ? dest : NULL,
+				     rename_branch == opt->branch1 ? NULL : dest);
 }
 
-static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
-						 struct stage_data *entry,
-						 int stage)
-{
-	struct object_id *oid = &entry->stages[stage].oid;
-	unsigned mode = entry->stages[stage].mode;
-	if (mode == 0 || is_null_oid(oid))
-		return NULL;
-	oidcpy(&target->oid, oid);
-	target->mode = mode;
-	return target;
-}
-
-static int handle_file_collision(struct merge_options *o,
+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,
-				 const struct object_id *a_oid,
-				 unsigned int a_mode,
-				 const struct object_id *b_oid,
-				 unsigned int b_mode)
+				 struct diff_filespec *a,
+				 struct diff_filespec *b)
 {
 	struct merge_file_info mfi;
-	struct diff_filespec null, a, b;
+	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 == o->branch1.  So, simply
+	 * branch if we just ensure that branch1 == opt->branch1.  So, simply
 	 * flip arguments around if we don't have that.
 	 */
-	if (branch1 != o->branch1) {
-		return handle_file_collision(o, collide_path,
+	if (branch1 != opt->branch1) {
+		return handle_file_collision(opt, collide_path,
 					     prev_path2, prev_path1,
 					     branch2, branch1,
-					     b_oid, b_mode,
-					     a_oid, a_mode);
+					     b, a);
 	}
 
 	/*
 	 * In the recursive case, we just opt to undo renames
 	 */
-	if (o->call_depth && (prev_path1 || prev_path2)) {
-		/* Put first file (a_oid, a_mode) in its original spot */
+	if (opt->call_depth && (prev_path1 || prev_path2)) {
+		/* Put first file (a->oid, a->mode) in its original spot */
 		if (prev_path1) {
-			if (update_file(o, 1, a_oid, a_mode, prev_path1))
+			if (update_file(opt, 1, a, prev_path1))
 				return -1;
 		} else {
-			if (update_file(o, 1, a_oid, a_mode, collide_path))
+			if (update_file(opt, 1, a, collide_path))
 				return -1;
 		}
 
-		/* Put second file (b_oid, b_mode) in its original spot */
+		/* Put second file (b->oid, b->mode) in its original spot */
 		if (prev_path2) {
-			if (update_file(o, 1, b_oid, b_mode, prev_path2))
+			if (update_file(opt, 1, b, prev_path2))
 				return -1;
 		} else {
-			if (update_file(o, 1, b_oid, b_mode, collide_path))
+			if (update_file(opt, 1, b, collide_path))
 				return -1;
 		}
 
 		/* Don't leave something at collision path if unrenaming both */
 		if (prev_path1 && prev_path2)
-			remove_file(o, 1, collide_path, 0);
+			remove_file(opt, 1, collide_path, 0);
 
 		return 0;
 	}
 
 	/* Remove rename sources if rename/add or rename/rename(2to1) */
 	if (prev_path1)
-		remove_file(o, 1, prev_path1,
-			    o->call_depth || would_lose_untracked(o, prev_path1));
+		remove_file(opt, 1, prev_path1,
+			    opt->call_depth || would_lose_untracked(opt, prev_path1));
 	if (prev_path2)
-		remove_file(o, 1, prev_path2,
-			    o->call_depth || would_lose_untracked(o, prev_path2));
+		remove_file(opt, 1, prev_path2,
+			    opt->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(o, collide_path)) {
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+	if (was_dirty(opt, collide_path)) {
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       collide_path);
-		update_path = alt_path = unique_path(o, collide_path, "merged");
-	} else if (would_lose_untracked(o, 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(o, 1, _("Refusing to lose untracked file at "
+		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(o, collide_path, "merged");
+		update_path = alt_path = unique_path(opt, collide_path, "merged");
 	} else {
 		/*
 		 * FIXME: It's possible that the two files are identical
@@ -1654,30 +1606,22 @@ static int handle_file_collision(struct merge_options *o,
 		 * merge-recursive interoperate anyway, so punting for
 		 * now...
 		 */
-		remove_file(o, 0, collide_path, 0);
+		remove_file(opt, 0, collide_path, 0);
 	}
 
 	/* Store things in diff_filespecs for functions that need it */
-	memset(&a, 0, sizeof(struct diff_filespec));
-	memset(&b, 0, sizeof(struct diff_filespec));
-	null.path = a.path = b.path = (char *)collide_path;
+	null.path = (char *)collide_path;
 	oidcpy(&null.oid, &null_oid);
 	null.mode = 0;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	a.oid_valid = 1;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-	b.oid_valid = 1;
-
-	if (merge_mode_and_contents(o, &null, &a, &b, collide_path,
-				    branch1, branch2, o->call_depth * 2, &mfi))
+
+	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
+				    branch1, branch2, opt->call_depth * 2, &mfi))
 		return -1;
 	mfi.clean &= !alt_path;
-	if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, update_path))
+	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
 		return -1;
-	if (!mfi.clean && !o->call_depth &&
-	    update_stages(o, collide_path, NULL, &a, &b))
+	if (!mfi.clean && !opt->call_depth &&
+	    update_stages(opt, collide_path, NULL, a, b))
 		return -1;
 	free(alt_path);
 	/*
@@ -1690,52 +1634,57 @@ static int handle_file_collision(struct merge_options *o,
 	return mfi.clean;
 }
 
-static int handle_rename_add(struct merge_options *o,
+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->pair1->one;
-	struct diff_filespec *c = ci->pair1->two;
+	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;
 
-	int other_stage = (ci->branch1 == o->branch1 ? 3 : 2);
+	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(o, 1, _("CONFLICT (rename/add): "
+	output(opt, 1, _("CONFLICT (rename/add): "
 	       "Rename %s->%s in %s.  Added %s in %s"),
-	       a->path, c->path, ci->branch1,
-	       c->path, ci->branch2);
+	       a->path, c->path, rename_branch,
+	       c->path, add_branch);
 
 	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	if (merge_mode_and_contents(o, a, c, &ci->ren1_other, prev_path_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi))
+	if (merge_mode_and_contents(opt, a, c,
+				    &ci->ren1->src_entry->stages[other_stage],
+				    prev_path_desc,
+				    opt->branch1, opt->branch2,
+				    1 + opt->call_depth * 2, &mfi))
 		return -1;
 	free(prev_path_desc);
 
-	return handle_file_collision(o,
+	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
+	return handle_file_collision(opt,
 				     c->path, a->path, NULL,
-				     ci->branch1, ci->branch2,
-				     &mfi.oid, mfi.mode,
-				     &ci->dst_entry1->stages[other_stage].oid,
-				     ci->dst_entry1->stages[other_stage].mode);
+				     rename_branch, add_branch,
+				     &mfi.blob,
+				     &ci->ren1->dst_entry->stages[other_stage]);
 }
 
-static char *find_path_for_conflict(struct merge_options *o,
+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(o->repo->index, path, !o->call_depth, 0)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("%s is a directory in %s adding "
+	if (dir_in_way(opt->repo->index, path, !opt->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(o, path)) {
-		new_path = unique_path(o, path, branch1);
-		output(o, 1, _("Refusing to lose untracked file"
+	} 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);
 	}
@@ -1743,41 +1692,40 @@ static char *find_path_for_conflict(struct merge_options *o,
 	return new_path;
 }
 
-static int handle_rename_rename_1to2(struct merge_options *o,
+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 other;
 	struct diff_filespec *add;
-	struct diff_filespec *one = ci->pair1->one;
-	struct diff_filespec *a = ci->pair1->two;
-	struct diff_filespec *b = ci->pair2->two;
+	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(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       one->path, a->path, ci->branch1,
-	       one->path, b->path, ci->branch2,
-	       o->call_depth ? _(" (left unresolved)") : "");
+	       o->path, a->path, ci->ren1->branch,
+	       o->path, b->path, ci->ren2->branch,
+	       opt->call_depth ? _(" (left unresolved)") : "");
 
 	path_desc = xstrfmt("%s and %s, both renamed from %s",
-			    a->path, b->path, one->path);
-	if (merge_mode_and_contents(o, one, a, b, path_desc,
-				    ci->branch1, ci->branch2,
-				    o->call_depth * 2, &mfi))
+			    a->path, b->path, o->path);
+	if (merge_mode_and_contents(opt, o, a, b, path_desc,
+				    ci->ren1->branch, ci->ren2->branch,
+				    opt->call_depth * 2, &mfi))
 		return -1;
 	free(path_desc);
 
-	if (o->call_depth) {
+	if (opt->call_depth) {
 		/*
 		 * FIXME: For rename/add-source conflicts (if we could detect
 		 * such), this is wrong.  We should instead find a unique
 		 * pathname and then either rename the add-source file to that
 		 * unique path, or use that unique path instead of src here.
 		 */
-		if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
+		if (update_file(opt, 0, &mfi.blob, o->path))
 			return -1;
 
 		/*
@@ -1788,61 +1736,65 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 		 * such cases, we should keep the added file around,
 		 * resolving the conflict at that path in its favor.
 		 */
-		add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
-		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, a->path))
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, a->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, a->path);
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
-		if (add) {
-			if (update_file(o, 0, &add->oid, add->mode, b->path))
+			remove_file_from_index(opt->repo->index, a->path);
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			if (update_file(opt, 0, add, b->path))
 				return -1;
 		}
 		else
-			remove_file_from_index(o->repo->index, b->path);
+			remove_file_from_index(opt->repo->index, b->path);
 	} else {
 		/*
 		 * 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 = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
-		if (add) {
-			if (handle_file_collision(o, a->path,
+		add = &ci->ren1->dst_entry->stages[2 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = a->path;
+			if (handle_file_collision(opt, a->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
-						  &mfi.oid, mfi.mode,
-						  &add->oid, add->mode) < 0)
+						  ci->ren1->branch,
+						  ci->ren2->branch,
+						  &mfi.blob, add) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, a->path,
-								ci->branch1,
-								ci->branch2);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : a->path))
+			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 (update_stages(o, a->path, NULL, a, NULL))
+			if (update_stages(opt, a->path, NULL, a, NULL))
 				return -1;
 		}
 
-		add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
-		if (add) {
-			if (handle_file_collision(o, b->path,
+		add = &ci->ren2->dst_entry->stages[3 ^ 1];
+		if (is_valid(add)) {
+			add->path = mfi.blob.path = b->path;
+			if (handle_file_collision(opt, b->path,
 						  NULL, NULL,
-						  ci->branch1, ci->branch2,
-						  &add->oid, add->mode,
-						  &mfi.oid, mfi.mode) < 0)
+						  ci->ren1->branch,
+						  ci->ren2->branch,
+						  add, &mfi.blob) < 0)
 				return -1;
 		} else {
-			char *new_path = find_path_for_conflict(o, b->path,
-								ci->branch2,
-								ci->branch1);
-			if (update_file(o, 0, &mfi.oid, mfi.mode, new_path ? new_path : b->path))
+			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 (update_stages(o, b->path, NULL, NULL, b))
+			if (update_stages(opt, b->path, NULL, NULL, b))
 				return -1;
 		}
 	}
@@ -1850,58 +1802,68 @@ static int handle_rename_rename_1to2(struct merge_options *o,
 	return 0;
 }
 
-static int handle_rename_rename_2to1(struct merge_options *o,
+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->pair1->one;
-	struct diff_filespec *b = ci->pair2->one;
-	struct diff_filespec *c1 = ci->pair1->two;
-	struct diff_filespec *c2 = ci->pair2->two;
+	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(o, 1, _("CONFLICT (rename/rename): "
+	output(opt, 1, _("CONFLICT (rename/rename): "
 	       "Rename %s->%s in %s. "
 	       "Rename %s->%s in %s"),
-	       a->path, c1->path, ci->branch1,
-	       b->path, c2->path, ci->branch2);
+	       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);
-	if (merge_mode_and_contents(o, a, c1, &ci->ren1_other, path_side_1_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(o, b, &ci->ren2_other, c2, path_side_2_desc,
-				    o->branch1, o->branch2,
-				    1 + o->call_depth * 2, &mfi_c2))
+	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
+	ostage2 = ostage1 ^ 1;
+	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->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->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(o, path, a->path, b->path,
-				     ci->branch1, ci->branch2,
-				     &mfi_c1.oid, mfi_c1.mode,
-				     &mfi_c2.oid, mfi_c2.mode);
+	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 *o,
+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(o->repo, &opts);
+	repo_diff_setup(opt->repo, &opts);
 	opts.flags.recursive = 1;
 	opts.flags.rename_empty = 0;
-	opts.detect_rename = merge_detect_rename(o);
+	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
@@ -1910,17 +1872,17 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 	 */
 	if (opts.detect_rename > DIFF_DETECT_RENAME)
 		opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
-			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
+	opts.rename_limit = opt->merge_rename_limit >= 0 ? opt->merge_rename_limit :
+			    opt->diff_rename_limit >= 0 ? opt->diff_rename_limit :
 			    1000;
-	opts.rename_score = o->rename_score;
-	opts.show_rename_progress = o->show_rename_progress;
+	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 > o->needed_rename_limit)
-		o->needed_rename_limit = opts.needed_rename_limit;
+	if (opts.needed_rename_limit > opt->needed_rename_limit)
+		opt->needed_rename_limit = opts.needed_rename_limit;
 
 	ret = xmalloc(sizeof(*ret));
 	*ret = diff_queued_diff;
@@ -1935,7 +1897,7 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
 static int tree_has_path(struct tree *tree, const char *path)
 {
 	struct object_id hashy;
-	unsigned int mode_o;
+	unsigned short mode_o;
 
 	return !get_tree_entry(&tree->object.oid, path,
 			       &hashy, &mode_o);
@@ -2039,7 +2001,7 @@ static void remove_hashmap_entries(struct hashmap *dir_renames,
  * 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 *o,
+static char *handle_path_level_conflicts(struct merge_options *opt,
 					 const char *path,
 					 struct dir_rename_entry *entry,
 					 struct hashmap *collisions,
@@ -2060,7 +2022,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		/* 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(o, 1, _("CONFLICT (directory rename split): "
+		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 "
@@ -2092,7 +2054,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Existing "
+		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."),
@@ -2102,7 +2064,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
 		collision_ent->reported_already = 1;
 		strbuf_add_separated_string_list(&collision_paths, ", ",
 						 &collision_ent->source_files);
-		output(o, 1, _("CONFLICT (implicit dir rename): Cannot map "
+		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);
@@ -2139,7 +2101,7 @@ static char *handle_path_level_conflicts(struct merge_options *o,
  *         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 *o,
+static void handle_directory_level_conflicts(struct merge_options *opt,
 					     struct hashmap *dir_re_head,
 					     struct tree *head,
 					     struct hashmap *dir_re_merge,
@@ -2194,11 +2156,11 @@ static void handle_directory_level_conflicts(struct merge_options *o,
 			 * know that head_ent->new_dir and merge_ent->new_dir
 			 * are different strings.
 			 */
-			output(o, 1, _("CONFLICT (rename/rename): "
+			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, o->branch1,
-			       head_ent->dir, merge_ent->new_dir.buf, o->branch2);
+			       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);
@@ -2397,7 +2359,7 @@ static void compute_collisions(struct hashmap *collisions,
 	}
 }
 
-static char *check_for_directory_rename(struct merge_options *o,
+static char *check_for_directory_rename(struct merge_options *opt,
 					const char *path,
 					struct tree *tree,
 					struct hashmap *dir_renames,
@@ -2438,11 +2400,11 @@ static char *check_for_directory_rename(struct merge_options *o,
 	 */
 	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
 	if (oentry) {
-		output(o, 1, _("WARNING: Avoiding applying %s -> %s rename "
+		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(o, path, entry,
+		new_path = handle_path_level_conflicts(opt, path, entry,
 						       collisions, tree);
 		*clean_merge &= (new_path != NULL);
 	}
@@ -2450,7 +2412,7 @@ static char *check_for_directory_rename(struct merge_options *o,
 	return new_path;
 }
 
-static void apply_directory_rename_modifications(struct merge_options *o,
+static void apply_directory_rename_modifications(struct merge_options *opt,
 						 struct diff_filepair *pair,
 						 char *new_path,
 						 struct rename *re,
@@ -2473,11 +2435,11 @@ static void apply_directory_rename_modifications(struct merge_options *o,
 	 * saying the file would have been overwritten), but it might
 	 * be dirty, though.
 	 */
-	update_wd = !was_dirty(o, pair->two->path);
+	update_wd = !was_dirty(opt, pair->two->path);
 	if (!update_wd)
-		output(o, 1, _("Refusing to lose dirty file at %s"),
+		output(opt, 1, _("Refusing to lose dirty file at %s"),
 		       pair->two->path);
-	remove_file(o, 1, pair->two->path, !update_wd);
+	remove_file(opt, 1, pair->two->path, !update_wd);
 
 	/* Find or create a new re->dst_entry */
 	item = string_list_lookup(entries, new_path);
@@ -2537,16 +2499,18 @@ static void apply_directory_rename_modifications(struct merge_options *o,
 		       &re->dst_entry->stages[stage].oid,
 		       &re->dst_entry->stages[stage].mode);
 
-	/* Update pair status */
-	if (pair->status == 'A') {
-		/*
-		 * Recording rename information for this add makes it look
-		 * like a rename/delete conflict.  Make sure we can
-		 * correctly handle this as an add that was moved to a new
-		 * directory instead of reporting a rename/delete conflict.
-		 */
-		re->add_turned_into_rename = 1;
-	}
+	/*
+	 * 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.
@@ -2566,7 +2530,8 @@ static void apply_directory_rename_modifications(struct merge_options *o,
  * 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 *o,
+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,
@@ -2596,7 +2561,7 @@ static struct string_list *get_renames(struct merge_options *o,
 			diff_free_filepair(pair);
 			continue;
 		}
-		new_path = check_for_directory_rename(o, pair->two->path, tree,
+		new_path = check_for_directory_rename(opt, pair->two->path, tree,
 						      dir_renames,
 						      dir_rename_exclusions,
 						      &collisions,
@@ -2608,8 +2573,10 @@ static struct string_list *get_renames(struct merge_options *o,
 
 		re = xmalloc(sizeof(*re));
 		re->processed = 0;
-		re->add_turned_into_rename = 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(re->pair->one->path,
@@ -2626,7 +2593,7 @@ static struct string_list *get_renames(struct merge_options *o,
 		item = string_list_insert(renames, pair->one->path);
 		item->util = re;
 		if (new_path)
-			apply_directory_rename_modifications(o, pair, new_path,
+			apply_directory_rename_modifications(opt, pair, new_path,
 							     re, tree, o_tree,
 							     a_tree, b_tree,
 							     entries);
@@ -2641,7 +2608,7 @@ static struct string_list *get_renames(struct merge_options *o,
 	return renames;
 }
 
-static int process_renames(struct merge_options *o,
+static int process_renames(struct merge_options *opt,
 			   struct string_list *a_renames,
 			   struct string_list *b_renames)
 {
@@ -2664,7 +2631,6 @@ static int process_renames(struct merge_options *o,
 	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 *branch1, *branch2;
 		const char *ren1_src, *ren1_dst;
 		struct string_list_item *lookup;
 
@@ -2685,13 +2651,9 @@ static int process_renames(struct merge_options *o,
 		if (ren1) {
 			renames1 = a_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = o->branch1;
-			branch2 = o->branch2;
 		} else {
 			renames1 = b_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = o->branch2;
-			branch2 = o->branch1;
 			SWAP(ren2, ren1);
 		}
 
@@ -2725,22 +2687,13 @@ static int process_renames(struct merge_options *o,
 				 * the base stage (think of rename +
 				 * add-source cases).
 				 */
-				remove_file(o, 1, ren1_src, 1);
+				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,
-						   ren1->pair,
-						   ren2->pair,
-						   branch1,
-						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   o,
-						   NULL,
-						   NULL);
+			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;
@@ -2759,16 +2712,7 @@ static int process_renames(struct merge_options *o,
 			ren2->src_entry->processed = 1;
 
 			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   ren1->pair,
-						   ren2->pair,
-						   branch1,
-						   branch2,
-						   ren1->dst_entry,
-						   ren2->dst_entry,
-						   o,
-						   ren1->src_entry,
-						   ren2->src_entry);
-
+						   opt, ren1, ren2);
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
 			/* we only use sha1 and mode of these */
@@ -2788,8 +2732,8 @@ static int process_renames(struct merge_options *o,
 			 * stage and in other_stage (think of rename +
 			 * add-source case).
 			 */
-			remove_file(o, 1, ren1_src,
-				    renamed_stage == 2 || !was_tracked(o, ren1_src));
+			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);
@@ -2800,28 +2744,12 @@ static int process_renames(struct merge_options *o,
 			try_merge = 0;
 
 			if (oid_eq(&src_other.oid, &null_oid) &&
-			    ren1->add_turned_into_rename) {
+			    ren1->dir_rename_original_type == 'A') {
 				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   ren1->pair,
-							   NULL,
-							   branch1,
-							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   o,
-							   NULL,
-							   NULL);
+							   opt, ren1, NULL);
 			} else if (oid_eq(&src_other.oid, &null_oid)) {
 				setup_rename_conflict_info(RENAME_DELETE,
-							   ren1->pair,
-							   NULL,
-							   branch1,
-							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   o,
-							   NULL,
-							   NULL);
+							   opt, ren1, NULL);
 			} else if ((dst_other.mode == ren1->pair->two->mode) &&
 				   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
 				/*
@@ -2832,9 +2760,8 @@ static int process_renames(struct merge_options *o,
 				 * update_file_flags() instead of
 				 * update_file().
 				 */
-				if (update_file_flags(o,
-						      &ren1->pair->two->oid,
-						      ren1->pair->two->mode,
+				if (update_file_flags(opt,
+						      ren1->pair->two,
 						      ren1_dst,
 						      1, /* update_cache */
 						      0  /* update_wd    */))
@@ -2848,25 +2775,17 @@ static int process_renames(struct merge_options *o,
 				 * file, then the merge will be clean.
 				 */
 				setup_rename_conflict_info(RENAME_ADD,
-							   ren1->pair,
-							   NULL,
-							   branch1,
-							   branch2,
-							   ren1->dst_entry,
-							   NULL,
-							   o,
-							   ren1->src_entry,
-							   NULL);
+							   opt, ren1, NULL);
 			} else
 				try_merge = 1;
 
 			if (clean_merge < 0)
 				goto cleanup_and_return;
 			if (try_merge) {
-				struct diff_filespec *one, *a, *b;
+				struct diff_filespec *o, *a, *b;
 				src_other.path = (char *)ren1_src;
 
-				one = ren1->pair->one;
+				o = ren1->pair->one;
 				if (a_renames == renames1) {
 					a = ren1->pair->two;
 					b = &src_other;
@@ -2874,17 +2793,9 @@ static int process_renames(struct merge_options *o,
 					b = ren1->pair->two;
 					a = &src_other;
 				}
-				update_entry(ren1->dst_entry, one, a, b);
+				update_entry(ren1->dst_entry, o, a, b);
 				setup_rename_conflict_info(RENAME_NORMAL,
-							   ren1->pair,
-							   NULL,
-							   branch1,
-							   NULL,
-							   ren1->dst_entry,
-							   NULL,
-							   o,
-							   NULL,
-							   NULL);
+							   opt, ren1, NULL);
 			}
 		}
 	}
@@ -2919,7 +2830,7 @@ static void initial_cleanup_rename(struct diff_queue_struct *pairs,
 	free(pairs);
 }
 
-static int detect_and_process_renames(struct merge_options *o,
+static int detect_and_process_renames(struct merge_options *opt,
 				      struct tree *common,
 				      struct tree *head,
 				      struct tree *merge,
@@ -2933,17 +2844,17 @@ static int detect_and_process_renames(struct merge_options *o,
 	ri->head_renames = NULL;
 	ri->merge_renames = NULL;
 
-	if (!merge_detect_rename(o))
+	if (!merge_detect_rename(opt))
 		return 1;
 
-	head_pairs = get_diffpairs(o, common, head);
-	merge_pairs = get_diffpairs(o, common, merge);
+	head_pairs = get_diffpairs(opt, common, head);
+	merge_pairs = get_diffpairs(opt, common, merge);
 
-	if (o->detect_directory_renames) {
+	if (opt->detect_directory_renames) {
 		dir_re_head = get_directory_renames(head_pairs);
 		dir_re_merge = get_directory_renames(merge_pairs);
 
-		handle_directory_level_conflicts(o,
+		handle_directory_level_conflicts(opt,
 						 dir_re_head, head,
 						 dir_re_merge, merge);
 	} else {
@@ -2953,19 +2864,19 @@ static int detect_and_process_renames(struct merge_options *o,
 		dir_rename_init(dir_re_merge);
 	}
 
-	ri->head_renames  = get_renames(o, head_pairs,
+	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(o, merge_pairs,
+	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(o, ri->head_renames, ri->merge_renames);
+	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);
 
 cleanup:
 	/*
@@ -3001,12 +2912,7 @@ static void final_cleanup_renames(struct rename_info *re_info)
 	final_cleanup_rename(re_info->merge_renames);
 }
 
-static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
-{
-	return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
-}
-
-static int read_oid_strbuf(struct merge_options *o,
+static int read_oid_strbuf(struct merge_options *opt,
 			   const struct object_id *oid,
 			   struct strbuf *dst)
 {
@@ -3015,130 +2921,99 @@ static int read_oid_strbuf(struct merge_options *o,
 	unsigned long size;
 	buf = read_object_file(oid, &type, &size);
 	if (!buf)
-		return err(o, _("cannot read object %s"), oid_to_hex(oid));
+		return err(opt, _("cannot read object %s"), oid_to_hex(oid));
 	if (type != OBJ_BLOB) {
 		free(buf);
-		return err(o, _("object %s is not a blob"), oid_to_hex(oid));
+		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 object_id *o_oid,
-			  unsigned o_mode,
-			  const struct object_id *a_oid,
-			  unsigned a_mode,
+			  const struct diff_filespec *o,
+			  const struct diff_filespec *a,
 			  int renormalize, const char *path)
 {
-	struct strbuf o = STRBUF_INIT;
-	struct strbuf a = STRBUF_INIT;
+	struct strbuf obuf = STRBUF_INIT;
+	struct strbuf abuf = STRBUF_INIT;
 	int ret = 0; /* assume changed for safety */
+	const struct index_state *idx = opt->repo->index;
 
-	if (a_mode != o_mode)
+	if (a->mode != o->mode)
 		return 0;
-	if (oid_eq(o_oid, a_oid))
+	if (oid_eq(&o->oid, &a->oid))
 		return 1;
 	if (!renormalize)
 		return 0;
 
-	assert(o_oid && a_oid);
-	if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
+	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(opt->repo->index, path, o.buf, o.len, &o) |
-	    renormalize_buffer(opt->repo->index, path, a.buf, a.len, &a))
-		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+	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(&o);
-	strbuf_release(&a);
+	strbuf_release(&obuf);
+	strbuf_release(&abuf);
 	return ret;
 }
 
-static int handle_modify_delete(struct merge_options *o,
+static int handle_modify_delete(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode)
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b)
 {
 	const char *modify_branch, *delete_branch;
-	struct object_id *changed_oid;
-	int changed_mode;
-
-	if (a_oid) {
-		modify_branch = o->branch1;
-		delete_branch = o->branch2;
-		changed_oid = a_oid;
-		changed_mode = a_mode;
+	const struct diff_filespec *changed;
+
+	if (is_valid(a)) {
+		modify_branch = opt->branch1;
+		delete_branch = opt->branch2;
+		changed = a;
 	} else {
-		modify_branch = o->branch2;
-		delete_branch = o->branch1;
-		changed_oid = b_oid;
-		changed_mode = b_mode;
+		modify_branch = opt->branch2;
+		delete_branch = opt->branch1;
+		changed = b;
 	}
 
-	return handle_change_delete(o,
+	return handle_change_delete(opt,
 				    path, NULL,
-				    o_oid, o_mode,
-				    changed_oid, changed_mode,
+				    o, changed,
 				    modify_branch, delete_branch,
 				    _("modify"), _("modified"));
 }
 
-static int handle_content_merge(struct merge_options *o,
+static int handle_content_merge(struct merge_file_info *mfi,
+				struct merge_options *opt,
 				const char *path,
 				int is_dirty,
-				struct object_id *o_oid, int o_mode,
-				struct object_id *a_oid, int a_mode,
-				struct object_id *b_oid, int b_mode,
-				struct rename_conflict_info *rename_conflict_info)
+				const struct diff_filespec *o,
+				const struct diff_filespec *a,
+				const struct diff_filespec *b,
+				struct rename_conflict_info *ci)
 {
 	const char *reason = _("content");
-	const char *path1 = NULL, *path2 = NULL;
-	struct merge_file_info mfi;
-	struct diff_filespec one, a, b;
 	unsigned df_conflict_remains = 0;
 
-	if (!o_oid) {
+	if (!is_valid(o))
 		reason = _("add/add");
-		o_oid = (struct object_id *)&null_oid;
-	}
-	one.path = a.path = b.path = (char *)path;
-	oidcpy(&one.oid, o_oid);
-	one.mode = o_mode;
-	oidcpy(&a.oid, a_oid);
-	a.mode = a_mode;
-	oidcpy(&b.oid, b_oid);
-	b.mode = b_mode;
-
-	if (rename_conflict_info) {
-		struct diff_filepair *pair1 = rename_conflict_info->pair1;
-
-		path1 = (o->branch1 == rename_conflict_info->branch1) ?
-			pair1->two->path : pair1->one->path;
-		/* If rename_conflict_info->pair2 != NULL, we are in
-		 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
-		 * normal rename.
-		 */
-		path2 = (rename_conflict_info->pair2 ||
-			 o->branch2 == rename_conflict_info->branch1) ?
-			pair1->two->path : pair1->one->path;
-		one.path = pair1->one->path;
-		a.path = (char *)path1;
-		b.path = (char *)path2;
-
-		if (dir_in_way(o->repo->index, path, !o->call_depth,
-			       S_ISGITLINK(pair1->two->mode)))
-			df_conflict_remains = 1;
-	}
-	if (merge_mode_and_contents(o, &one, &a, &b, path,
-				    o->branch1, o->branch2,
-				    o->call_depth * 2, &mfi))
+
+	assert(o->path && a->path && b->path);
+	if (ci && dir_in_way(opt->repo->index, path, !opt->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->call_depth * 2, mfi))
 		return -1;
 
 	/*
@@ -3147,15 +3022,14 @@ static int handle_content_merge(struct merge_options *o,
 	 *   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(o, path, &mfi.oid, mfi.mode) &&
+	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
 	    !df_conflict_remains) {
 		int pos;
 		struct cache_entry *ce;
 
-		output(o, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(o, mfi.mode, &mfi.oid, path,
-				  0, (!o->call_depth && !is_dirty), 0))
+		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
+		if (add_cacheinfo(opt, &mfi->blob, path,
+				  0, (!opt->call_depth && !is_dirty), 0))
 			return -1;
 		/*
 		 * However, add_cacheinfo() will delete the old cache entry
@@ -3163,109 +3037,196 @@ static int handle_content_merge(struct merge_options *o,
 		 * flag to avoid making the file appear as if it were
 		 * deleted by the user.
 		 */
-		pos = index_name_pos(&o->orig_index, path, strlen(path));
-		ce = o->orig_index.cache[pos];
+		pos = index_name_pos(&opt->orig_index, path, strlen(path));
+		ce = opt->orig_index.cache[pos];
 		if (ce_skip_worktree(ce)) {
-			pos = index_name_pos(o->repo->index, path, strlen(path));
-			ce = o->repo->index->cache[pos];
+			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;
+		return mfi->clean;
 	}
 
-	if (!mfi.clean) {
-		if (S_ISGITLINK(mfi.mode))
+	if (!mfi->clean) {
+		if (S_ISGITLINK(mfi->blob.mode))
 			reason = _("submodule");
-		output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
+		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
 				reason, path);
-		if (rename_conflict_info && !df_conflict_remains)
-			if (update_stages(o, path, &one, &a, &b))
+		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 (o->call_depth) {
-			remove_file_from_index(o->repo->index, path);
+		if (opt->call_depth) {
+			remove_file_from_index(opt->repo->index, path);
 		} else {
-			if (!mfi.clean) {
-				if (update_stages(o, path, &one, &a, &b))
+			if (!mfi->clean) {
+				if (update_stages(opt, path, o, a, b))
 					return -1;
 			} else {
-				int file_from_stage2 = was_tracked(o, path);
-				struct diff_filespec merged;
-				oidcpy(&merged.oid, &mfi.oid);
-				merged.mode = mfi.mode;
-
-				if (update_stages(o, path, NULL,
-						  file_from_stage2 ? &merged : NULL,
-						  file_from_stage2 ? NULL : &merged))
+				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(o, path, rename_conflict_info->branch1);
+		new_path = unique_path(opt, path, ci->ren1->branch);
 		if (is_dirty) {
-			output(o, 1, _("Refusing to lose dirty file at %s"),
+			output(opt, 1, _("Refusing to lose dirty file at %s"),
 			       path);
 		}
-		output(o, 1, _("Adding as %s instead"), new_path);
-		if (update_file(o, 0, &mfi.oid, mfi.mode, new_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(o, mfi.clean, &mfi.oid, mfi.mode, path))
+		mfi->clean = 0;
+	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
 		return -1;
-	return !is_dirty && mfi.clean;
+	return !is_dirty && mfi->clean;
 }
 
-static int handle_rename_normal(struct merge_options *o,
+static int handle_rename_normal(struct merge_options *opt,
 				const char *path,
-				struct object_id *o_oid, unsigned int o_mode,
-				struct object_id *a_oid, unsigned int a_mode,
-				struct object_id *b_oid, unsigned int b_mode,
+				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 */
-	return handle_content_merge(o, path, was_dirty(o, path),
-				    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
-				    ci);
+	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
+				     o, a, b, ci);
+
+	if (clean && opt->detect_directory_renames == 1 &&
+	    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 > 0);
+	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 == 2);
+
+	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 *o,
+static int process_entry(struct merge_options *opt,
 			 const char *path, struct stage_data *entry)
 {
 	int clean_merge = 1;
-	int normalize = o->renormalize;
-	unsigned o_mode = entry->stages[1].mode;
-	unsigned a_mode = entry->stages[2].mode;
-	unsigned b_mode = entry->stages[3].mode;
-	struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
-	struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
-	struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
+	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 *conflict_info = entry->rename_conflict_info;
-		switch (conflict_info->rename_type) {
+		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(o,
-							   path,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
-							   conflict_info);
+			clean_merge = handle_rename_normal(opt, path, o, a, b,
+							   ci);
 			break;
 		case RENAME_VIA_DIR:
-			clean_merge = 1;
-			if (handle_rename_via_dir(o,
-						  conflict_info->pair1,
-						  conflict_info->branch1))
-				clean_merge = -1;
+			clean_merge = handle_rename_via_dir(opt, ci);
 			break;
 		case RENAME_ADD:
 			/*
@@ -3274,165 +3235,172 @@ static int process_entry(struct merge_options *o,
 			 * two-way merged cleanly with the added file, I
 			 * guess it's a clean merge?
 			 */
-			clean_merge = handle_rename_add(o, conflict_info);
+			clean_merge = handle_rename_add(opt, ci);
 			break;
 		case RENAME_DELETE:
 			clean_merge = 0;
-			if (handle_rename_delete(o,
-						 conflict_info->pair1,
-						 conflict_info->branch1,
-						 conflict_info->branch2))
+			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(o, conflict_info))
+			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(o,
-								conflict_info);
+			clean_merge = handle_rename_rename_2to1(opt, ci);
 			break;
 		default:
 			entry->processed = 0;
 			break;
 		}
-	} else if (o_oid && (!a_oid || !b_oid)) {
+		if (path_clean < clean_merge)
+			clean_merge = path_clean;
+	} else if (o_valid && (!a_valid || !b_valid)) {
 		/* Case A: Deleted in one */
-		if ((!a_oid && !b_oid) ||
-		    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
-		    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
+		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_oid)
-				output(o, 2, _("Removing %s"), path);
+			if (a_valid)
+				output(opt, 2, _("Removing %s"), path);
 			/* do not touch working file if it did not exist */
-			remove_file(o, 1, path, !a_oid);
+			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(o, path, o_oid, o_mode,
-						 a_oid, a_mode, b_oid, b_mode))
+			if (handle_modify_delete(opt, path, o, a, b))
 				clean_merge = -1;
 		}
-	} else if ((!o_oid && a_oid && !b_oid) ||
-		   (!o_oid && !a_oid && b_oid)) {
+	} 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;
-		unsigned mode;
-		const struct object_id *oid;
 		const char *conf;
+		const struct diff_filespec *contents;
 
-		if (a_oid) {
-			add_branch = o->branch1;
-			other_branch = o->branch2;
-			mode = a_mode;
-			oid = a_oid;
+		if (a_valid) {
+			add_branch = opt->branch1;
+			other_branch = opt->branch2;
+			contents = a;
 			conf = _("file/directory");
 		} else {
-			add_branch = o->branch2;
-			other_branch = o->branch1;
-			mode = b_mode;
-			oid = b_oid;
+			add_branch = opt->branch2;
+			other_branch = opt->branch1;
+			contents = b;
 			conf = _("directory/file");
 		}
-		if (dir_in_way(o->repo->index, path,
-			       !o->call_depth && !S_ISGITLINK(a_mode),
+		if (dir_in_way(opt->repo->index, path,
+			       !opt->call_depth && !S_ISGITLINK(a->mode),
 			       0)) {
-			char *new_path = unique_path(o, path, add_branch);
+			char *new_path = unique_path(opt, path, add_branch);
 			clean_merge = 0;
-			output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
+			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(o, 0, oid, mode, new_path))
+			if (update_file(opt, 0, contents, new_path))
 				clean_merge = -1;
-			else if (o->call_depth)
-				remove_file_from_index(o->repo->index, path);
+			else if (opt->call_depth)
+				remove_file_from_index(opt->repo->index, path);
 			free(new_path);
 		} else {
-			output(o, 2, _("Adding %s"), path);
+			output(opt, 2, _("Adding %s"), path);
 			/* do not overwrite file if already present */
-			if (update_file_flags(o, oid, mode, path, 1, !a_oid))
+			if (update_file_flags(opt, contents, path, 1, !a_valid))
 				clean_merge = -1;
 		}
-	} else if (a_oid && b_oid) {
-		if (!o_oid) {
+	} else if (a_valid && b_valid) {
+		if (!o_valid) {
 			/* Case C: Added in both (check for same permissions) */
-			output(o, 1,
+			output(opt, 1,
 			       _("CONFLICT (add/add): Merge conflict in %s"),
 			       path);
-			clean_merge = handle_file_collision(o,
+			clean_merge = handle_file_collision(opt,
 							    path, NULL, NULL,
-							    o->branch1,
-							    o->branch2,
-							    a_oid, a_mode,
-							    b_oid, b_mode);
+							    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(o, path,
+			clean_merge = handle_content_merge(&mfi, opt, path,
 							   is_dirty,
-							   o_oid, o_mode,
-							   a_oid, a_mode,
-							   b_oid, b_mode,
-							   NULL);
+							   o, a, b, NULL);
 		}
-	} else if (!o_oid && !a_oid && !b_oid) {
+	} 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(o, 1, path, !a_mode);
+		remove_file(opt, 1, path, !a->mode);
 	} else
 		BUG("fatal merge failure, shouldn't happen.");
 
 	return clean_merge;
 }
 
-int merge_trees(struct merge_options *o,
+int merge_trees(struct merge_options *opt,
 		struct tree *head,
 		struct tree *merge,
 		struct tree *common,
 		struct tree **result)
 {
-	struct index_state *istate = o->repo->index;
+	struct index_state *istate = opt->repo->index;
 	int code, clean;
 	struct strbuf sb = STRBUF_INIT;
 
-	if (!o->call_depth && repo_index_has_changes(o->repo, head, &sb)) {
-		err(o, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
+	if (!opt->call_depth && 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);
 		return -1;
 	}
 
-	if (o->subtree_shift) {
-		merge = shift_tree_object(o->repo, head, merge, o->subtree_shift);
-		common = shift_tree_object(o->repo, head, common, o->subtree_shift);
+	if (opt->subtree_shift) {
+		merge = shift_tree_object(opt->repo, head, merge, opt->subtree_shift);
+		common = shift_tree_object(opt->repo, head, common, opt->subtree_shift);
 	}
 
 	if (oid_eq(&common->object.oid, &merge->object.oid)) {
-		output(o, 0, _("Already up to date!"));
+		output(opt, 0, _("Already up to date!"));
 		*result = head;
 		return 1;
 	}
 
-	code = unpack_trees_start(o, common, head, merge);
+	code = unpack_trees_start(opt, common, head, merge);
 
 	if (code != 0) {
-		if (show(o, 4) || o->call_depth)
-			err(o, _("merging of trees %s and %s failed"),
+		if (show(opt, 4) || opt->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(o);
+		unpack_trees_finish(opt);
 		return -1;
 	}
 
@@ -3447,21 +3415,21 @@ int merge_trees(struct merge_options *o,
 		 * opposed to decaring a local hashmap is for convenience
 		 * so that we don't have to pass it to around.
 		 */
-		hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
-		get_files_dirs(o, head);
-		get_files_dirs(o, merge);
+		hashmap_init(&opt->current_file_dir_set, path_hashmap_cmp, NULL, 512);
+		get_files_dirs(opt, head);
+		get_files_dirs(opt, merge);
 
-		entries = get_unmerged(o->repo->index);
-		clean = detect_and_process_renames(o, common, head, merge,
+		entries = get_unmerged(opt->repo->index);
+		clean = detect_and_process_renames(opt, common, head, merge,
 						   entries, &re_info);
-		record_df_conflict_files(o, entries);
+		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(o, path, e);
+				int ret = process_entry(opt, path, e);
 				if (!ret)
 					clean = 0;
 				else if (ret < 0) {
@@ -3483,19 +3451,19 @@ int merge_trees(struct merge_options *o,
 		string_list_clear(entries, 1);
 		free(entries);
 
-		hashmap_free(&o->current_file_dir_set, 1);
+		hashmap_free(&opt->current_file_dir_set, 1);
 
 		if (clean < 0) {
-			unpack_trees_finish(o);
+			unpack_trees_finish(opt);
 			return clean;
 		}
 	}
 	else
 		clean = 1;
 
-	unpack_trees_finish(o);
+	unpack_trees_finish(opt);
 
-	if (o->call_depth && !(*result = write_tree_from_memory(o)))
+	if (opt->call_depth && !(*result = write_tree_from_memory(opt)))
 		return -1;
 
 	return clean;
@@ -3516,7 +3484,7 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
  * Merge the commits h1 and h2, return the resulting virtual
  * commit object and a flag indicating the cleanness of the merge.
  */
-int merge_recursive(struct merge_options *o,
+int merge_recursive(struct merge_options *opt,
 		    struct commit *h1,
 		    struct commit *h2,
 		    struct commit_list *ca,
@@ -3527,10 +3495,10 @@ int merge_recursive(struct merge_options *o,
 	struct tree *mrtree;
 	int clean;
 
-	if (show(o, 4)) {
-		output(o, 4, _("Merging:"));
-		output_commit_title(o, h1);
-		output_commit_title(o, h2);
+	if (show(opt, 4)) {
+		output(opt, 4, _("Merging:"));
+		output_commit_title(opt, h1);
+		output_commit_title(opt, h2);
 	}
 
 	if (!ca) {
@@ -3538,13 +3506,13 @@ int merge_recursive(struct merge_options *o,
 		ca = reverse_commit_list(ca);
 	}
 
-	if (show(o, 5)) {
+	if (show(opt, 5)) {
 		unsigned cnt = commit_list_count(ca);
 
-		output(o, 5, Q_("found %u common ancestor:",
+		output(opt, 5, Q_("found %u common ancestor:",
 				"found %u common ancestors:", cnt), cnt);
 		for (iter = ca; iter; iter = iter->next)
-			output_commit_title(o, iter->item);
+			output_commit_title(opt, iter->item);
 	}
 
 	merged_common_ancestors = pop_commit(&ca);
@@ -3552,13 +3520,13 @@ int merge_recursive(struct merge_options *o,
 		/* if there is no common ancestor, use an empty tree */
 		struct tree *tree;
 
-		tree = lookup_tree(o->repo, o->repo->hash_algo->empty_tree);
-		merged_common_ancestors = make_virtual_commit(o->repo, tree, "ancestor");
+		tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
+		merged_common_ancestors = make_virtual_commit(opt->repo, tree, "ancestor");
 	}
 
 	for (iter = ca; iter; iter = iter->next) {
 		const char *saved_b1, *saved_b2;
-		o->call_depth++;
+		opt->call_depth++;
 		/*
 		 * When the merge fails, the result contains files
 		 * with conflict markers. The cleanness flag is
@@ -3567,46 +3535,46 @@ int merge_recursive(struct merge_options *o,
 		 * overwritten it: the committed "conflicts" were
 		 * already resolved.
 		 */
-		discard_index(o->repo->index);
-		saved_b1 = o->branch1;
-		saved_b2 = o->branch2;
-		o->branch1 = "Temporary merge branch 1";
-		o->branch2 = "Temporary merge branch 2";
-		if (merge_recursive(o, merged_common_ancestors, iter->item,
+		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(opt, merged_common_ancestors, iter->item,
 				    NULL, &merged_common_ancestors) < 0)
 			return -1;
-		o->branch1 = saved_b1;
-		o->branch2 = saved_b2;
-		o->call_depth--;
+		opt->branch1 = saved_b1;
+		opt->branch2 = saved_b2;
+		opt->call_depth--;
 
 		if (!merged_common_ancestors)
-			return err(o, _("merge returned no commit"));
+			return err(opt, _("merge returned no commit"));
 	}
 
-	discard_index(o->repo->index);
-	if (!o->call_depth)
-		repo_read_index(o->repo);
+	discard_index(opt->repo->index);
+	if (!opt->call_depth)
+		repo_read_index(opt->repo);
 
-	o->ancestor = "merged common ancestors";
-	clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+	opt->ancestor = "merged common ancestors";
+	clean = merge_trees(opt, get_commit_tree(h1), get_commit_tree(h2),
 			    get_commit_tree(merged_common_ancestors),
 			    &mrtree);
 	if (clean < 0) {
-		flush_output(o);
+		flush_output(opt);
 		return clean;
 	}
 
-	if (o->call_depth) {
-		*result = make_virtual_commit(o->repo, mrtree, "merged tree");
+	if (opt->call_depth) {
+		*result = make_virtual_commit(opt->repo, mrtree, "merged tree");
 		commit_list_insert(h1, &(*result)->parents);
 		commit_list_insert(h2, &(*result)->parents->next);
 	}
-	flush_output(o);
-	if (!o->call_depth && o->buffer_output < 2)
-		strbuf_release(&o->obuf);
-	if (show(o, 2))
+	flush_output(opt);
+	if (!opt->call_depth && opt->buffer_output < 2)
+		strbuf_release(&opt->obuf);
+	if (show(opt, 2))
 		diff_warn_rename_limit("merge.renamelimit",
-				       o->needed_rename_limit, 0);
+				       opt->needed_rename_limit, 0);
 	return clean;
 }
 
@@ -3628,7 +3596,7 @@ static struct commit *get_ref(struct repository *repo, const struct object_id *o
 	return (struct commit *)object;
 }
 
-int merge_recursive_generic(struct merge_options *o,
+int merge_recursive_generic(struct merge_options *opt,
 			    const struct object_id *head,
 			    const struct object_id *merge,
 			    int num_base_list,
@@ -3637,127 +3605,136 @@ int merge_recursive_generic(struct merge_options *o,
 {
 	int clean;
 	struct lock_file lock = LOCK_INIT;
-	struct commit *head_commit = get_ref(o->repo, head, o->branch1);
-	struct commit *next_commit = get_ref(o->repo, merge, o->branch2);
+	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 (base_list) {
 		int i;
 		for (i = 0; i < num_base_list; ++i) {
 			struct commit *base;
-			if (!(base = get_ref(o->repo, base_list[i], oid_to_hex(base_list[i]))))
-				return err(o, _("Could not parse object '%s'"),
+			if (!(base = get_ref(opt->repo, base_list[i], oid_to_hex(base_list[i]))))
+				return err(opt, _("Could not parse object '%s'"),
 					   oid_to_hex(base_list[i]));
 			commit_list_insert(base, &ca);
 		}
 	}
 
-	repo_hold_locked_index(o->repo, &lock, LOCK_DIE_ON_ERROR);
-	clean = merge_recursive(o, head_commit, next_commit, ca,
+	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(o->repo->index, &lock,
+	if (write_locked_index(opt->repo->index, &lock,
 			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
-		return err(o, _("Unable to write index."));
+		return err(opt, _("Unable to write index."));
 
 	return clean ? 0 : 1;
 }
 
-static void merge_recursive_config(struct merge_options *o)
+static void merge_recursive_config(struct merge_options *opt)
 {
 	char *value = NULL;
-	git_config_get_int("merge.verbosity", &o->verbosity);
-	git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
-	git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+	git_config_get_int("merge.verbosity", &opt->verbosity);
+	git_config_get_int("diff.renamelimit", &opt->diff_rename_limit);
+	git_config_get_int("merge.renamelimit", &opt->merge_rename_limit);
 	if (!git_config_get_string("diff.renames", &value)) {
-		o->diff_detect_rename = git_config_rename("diff.renames", value);
+		opt->diff_detect_rename = git_config_rename("diff.renames", value);
 		free(value);
 	}
 	if (!git_config_get_string("merge.renames", &value)) {
-		o->merge_detect_rename = git_config_rename("merge.renames", value);
+		opt->merge_detect_rename = 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 ? 2 : 0;
+		} else if (!strcasecmp(value, "conflict")) {
+			opt->detect_directory_renames = 1;
+		} /* avoid erroring on values from future versions of git */
 		free(value);
 	}
 	git_config(git_xmerge_config, NULL);
 }
 
-void init_merge_options(struct merge_options *o,
+void init_merge_options(struct merge_options *opt,
 			struct repository *repo)
 {
 	const char *merge_verbosity;
-	memset(o, 0, sizeof(struct merge_options));
-	o->repo = repo;
-	o->verbosity = 2;
-	o->buffer_output = 1;
-	o->diff_rename_limit = -1;
-	o->merge_rename_limit = -1;
-	o->renormalize = 0;
-	o->diff_detect_rename = -1;
-	o->merge_detect_rename = -1;
-	o->detect_directory_renames = 1;
-	merge_recursive_config(o);
+	memset(opt, 0, sizeof(struct merge_options));
+	opt->repo = repo;
+	opt->verbosity = 2;
+	opt->buffer_output = 1;
+	opt->diff_rename_limit = -1;
+	opt->merge_rename_limit = -1;
+	opt->renormalize = 0;
+	opt->diff_detect_rename = -1;
+	opt->merge_detect_rename = -1;
+	opt->detect_directory_renames = 1;
+	merge_recursive_config(opt);
 	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
 	if (merge_verbosity)
-		o->verbosity = strtol(merge_verbosity, NULL, 10);
-	if (o->verbosity >= 5)
-		o->buffer_output = 0;
-	strbuf_init(&o->obuf, 0);
-	string_list_init(&o->df_conflict_file_set, 1);
+		opt->verbosity = strtol(merge_verbosity, NULL, 10);
+	if (opt->verbosity >= 5)
+		opt->buffer_output = 0;
+	strbuf_init(&opt->obuf, 0);
+	string_list_init(&opt->df_conflict_file_set, 1);
 }
 
-int parse_merge_opt(struct merge_options *o, const char *s)
+int parse_merge_opt(struct merge_options *opt, const char *s)
 {
 	const char *arg;
 
 	if (!s || !*s)
 		return -1;
 	if (!strcmp(s, "ours"))
-		o->recursive_variant = MERGE_RECURSIVE_OURS;
+		opt->recursive_variant = MERGE_RECURSIVE_OURS;
 	else if (!strcmp(s, "theirs"))
-		o->recursive_variant = MERGE_RECURSIVE_THEIRS;
+		opt->recursive_variant = MERGE_RECURSIVE_THEIRS;
 	else if (!strcmp(s, "subtree"))
-		o->subtree_shift = "";
+		opt->subtree_shift = "";
 	else if (skip_prefix(s, "subtree=", &arg))
-		o->subtree_shift = arg;
+		opt->subtree_shift = arg;
 	else if (!strcmp(s, "patience"))
-		o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
+		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
 	else if (!strcmp(s, "histogram"))
-		o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
+		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(o, NEED_MINIMAL);
-		o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
-		o->xdl_opts |= value;
+		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(o, IGNORE_WHITESPACE_CHANGE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
 	else if (!strcmp(s, "ignore-all-space"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
 	else if (!strcmp(s, "ignore-space-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
 	else if (!strcmp(s, "ignore-cr-at-eol"))
-		DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
+		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
 	else if (!strcmp(s, "renormalize"))
-		o->renormalize = 1;
+		opt->renormalize = 1;
 	else if (!strcmp(s, "no-renormalize"))
-		o->renormalize = 0;
+		opt->renormalize = 0;
 	else if (!strcmp(s, "no-renames"))
-		o->merge_detect_rename = 0;
+		opt->merge_detect_rename = 0;
 	else if (!strcmp(s, "find-renames")) {
-		o->merge_detect_rename = 1;
-		o->rename_score = 0;
+		opt->merge_detect_rename = 1;
+		opt->rename_score = 0;
 	}
 	else if (skip_prefix(s, "find-renames=", &arg) ||
 		 skip_prefix(s, "rename-threshold=", &arg)) {
-		if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
+		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
 			return -1;
-		o->merge_detect_rename = 1;
+		opt->merge_detect_rename = 1;
 	}
 	/*
 	 * Please update $__git_merge_strategy_options in