Subject: [PATCH v3 6/8] merge-recursive.[ch]: thoroughly debug these

From: "Elijah Newren via GitGitGadget" <[email-masked]>
Date: Tue, 08 Apr 2025 15:48:40 +0000

From: Elijah Newren <[email-masked]>

As a wise man once told me, "Deleted code is debugged code!"  So, move
the functions that are shared between merge-recursive and merge-ort from
the former to the latter, and then debug the remainder of
merge-recursive.[ch].

Joking aside, merge-ort was always intended to replace merge-recursive.
It has numerous advantages over merge-recursive (operates much faster,
can operate without a worktree or index, and fixes a number of known
bugs and suboptimal merges).  Since we have now replaced all callers of
merge-recursive with equivalent functions from merge-ort, move the
shared functions from the former to the latter, and delete the remainder
of merge-recursive.[ch].

Signed-off-by: Elijah Newren <[email-masked]>
---
 Documentation/merge-strategies.adoc          |   24 +-
 Documentation/technical/sparse-checkout.adoc |    2 -
 Makefile                                     |    1 -
 merge-ort-wrappers.h                         |    2 +-
 merge-ort.c                                  |  159 +
 merge-ort.h                                  |   60 +-
 merge-recursive.c                            | 4080 ------------------
 merge-recursive.h                            |  132 -
 meson.build                                  |    1 -
 9 files changed, 225 insertions(+), 4236 deletions(-)
 delete mode 100644 merge-recursive.c
 delete mode 100644 merge-recursive.h

diff --git a/Documentation/merge-strategies.adoc b/Documentation/merge-strategies.adoc
index 8c87dd70210..9e034f447e7 100644
--- a/Documentation/merge-strategies.adoc
+++ b/Documentation/merge-strategies.adoc
@@ -109,23 +109,11 @@ subtree[=<path>];;
 	two trees to match.
 
 recursive::
-	This can only resolve two heads using a 3-way merge
-	algorithm.  When there is more than one common
-	ancestor that can be used for 3-way merge, it creates a
-	merged tree of the common ancestors and uses that as
-	the reference tree for the 3-way merge.  This has been
-	reported to result in fewer merge conflicts without
-	causing mismerges by tests done on actual merge commits
-	taken from Linux 2.6 kernel development history.
-	Additionally this can detect and handle merges involving
-	renames.  It does not make use of detected copies.  This was
-	the default strategy for resolving two heads from Git v0.99.9k
-	until v2.33.0.
-+
-For a path that is a submodule, the same caution as 'ort' applies to this
-strategy.
-+
-The 'recursive' strategy takes the same options as 'ort'.
+	This is now a synonym for `ort`.  It was an alternative
+	implementation until v2.49.0, but was redirected to mean `ort`
+	in v2.50.0.  The previous recursive strategy was the default
+	strategy for resolving two heads from Git v0.99.9k until
+	v2.33.0.
 
 resolve::
 	This can only resolve two heads (i.e. the current branch
@@ -146,7 +134,7 @@ ours::
 	ignoring all changes from all other branches.  It is meant to
 	be used to supersede old development history of side
 	branches.  Note that this is different from the -Xours option to
-	the 'recursive' merge strategy.
+	the 'ort' merge strategy.
 
 subtree::
 	This is a modified `ort` strategy. When merging trees A and
diff --git a/Documentation/technical/sparse-checkout.adoc b/Documentation/technical/sparse-checkout.adoc
index d9686593548..dc2e763bbec 100644
--- a/Documentation/technical/sparse-checkout.adoc
+++ b/Documentation/technical/sparse-checkout.adoc
@@ -356,8 +356,6 @@ understanding these differences can be beneficial.
     The behavior for these commands somewhat depends upon the merge
     strategy being used:
       * `ort` behaves as described above
-      * `recursive` tries to not vivify files unnecessarily, but does sometimes
-	vivify files without conflicts.
       * `octopus` and `resolve` will always vivify any file changed in the merge
 	relative to the first parent, which is rather suboptimal.
 
diff --git a/Makefile b/Makefile
index ac32d2d0bda..4fbd29cc7e9 100644
--- a/Makefile
+++ b/Makefile
@@ -1069,7 +1069,6 @@ LIB_OBJS += merge-blobs.o
 LIB_OBJS += merge-ll.o
 LIB_OBJS += merge-ort.o
 LIB_OBJS += merge-ort-wrappers.o
-LIB_OBJS += merge-recursive.o
 LIB_OBJS += merge.o
 LIB_OBJS += midx.o
 LIB_OBJS += midx-write.o
diff --git a/merge-ort-wrappers.h b/merge-ort-wrappers.h
index aeffa1c87b4..b7e1ced9d7f 100644
--- a/merge-ort-wrappers.h
+++ b/merge-ort-wrappers.h
@@ -1,7 +1,7 @@
 #ifndef MERGE_ORT_WRAPPERS_H
 #define MERGE_ORT_WRAPPERS_H
 
-#include "merge-recursive.h"
+#include "merge-ort.h"
 
 /*
  * rename-detecting three-way merge, no recursion.
diff --git a/merge-ort.c b/merge-ort.c
index 14a7ae4a6bf..f943f5ddcba 100644
--- a/merge-ort.c
+++ b/merge-ort.c
@@ -26,6 +26,7 @@
 #include "cache-tree.h"
 #include "commit.h"
 #include "commit-reach.h"
+#include "config.h"
 #include "diff.h"
 #include "diffcore.h"
 #include "dir.h"
@@ -5322,3 +5323,161 @@ void merge_incore_recursive(struct merge_options *opt,
 	merge_ort_internal(opt, merge_bases, side1, side2, result);
 	trace2_region_leave("merge", "incore_recursive", opt->repo);
 }
+
+static void merge_recursive_config(struct merge_options *opt, int ui)
+{
+	char *value = NULL;
+	int renormalize = 0;
+	git_config_get_int("merge.verbosity", &opt->verbosity);
+	git_config_get_int("diff.renamelimit", &opt->rename_limit);
+	git_config_get_int("merge.renamelimit", &opt->rename_limit);
+	git_config_get_bool("merge.renormalize", &renormalize);
+	opt->renormalize = renormalize;
+	if (!git_config_get_string("diff.renames", &value)) {
+		opt->detect_renames = git_config_rename("diff.renames", value);
+		free(value);
+	}
+	if (!git_config_get_string("merge.renames", &value)) {
+		opt->detect_renames = git_config_rename("merge.renames", value);
+		free(value);
+	}
+	if (!git_config_get_string("merge.directoryrenames", &value)) {
+		int boolval = git_parse_maybe_bool(value);
+		if (0 <= boolval) {
+			opt->detect_directory_renames = boolval ?
+				MERGE_DIRECTORY_RENAMES_TRUE :
+				MERGE_DIRECTORY_RENAMES_NONE;
+		} else if (!strcasecmp(value, "conflict")) {
+			opt->detect_directory_renames =
+				MERGE_DIRECTORY_RENAMES_CONFLICT;
+		} /* avoid erroring on values from future versions of git */
+		free(value);
+	}
+	if (ui) {
+		if (!git_config_get_string("diff.algorithm", &value)) {
+			long diff_algorithm = parse_algorithm_value(value);
+			if (diff_algorithm < 0)
+				die(_("unknown value for config '%s': %s"), "diff.algorithm", value);
+			opt->xdl_opts = (opt->xdl_opts & ~XDF_DIFF_ALGORITHM_MASK) | diff_algorithm;
+			free(value);
+		}
+	}
+	git_config(git_xmerge_config, NULL);
+}
+
+static void init_merge_options(struct merge_options *opt,
+			struct repository *repo, int ui)
+{
+	const char *merge_verbosity;
+	memset(opt, 0, sizeof(struct merge_options));
+
+	opt->repo = repo;
+
+	opt->detect_renames = -1;
+	opt->detect_directory_renames = MERGE_DIRECTORY_RENAMES_CONFLICT;
+	opt->rename_limit = -1;
+
+	opt->verbosity = 2;
+	opt->buffer_output = 1;
+	strbuf_init(&opt->obuf, 0);
+
+	opt->renormalize = 0;
+
+	opt->conflict_style = -1;
+	opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
+
+	merge_recursive_config(opt, ui);
+	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
+	if (merge_verbosity)
+		opt->verbosity = strtol(merge_verbosity, NULL, 10);
+	if (opt->verbosity >= 5)
+		opt->buffer_output = 0;
+}
+
+void init_ui_merge_options(struct merge_options *opt,
+			struct repository *repo)
+{
+	init_merge_options(opt, repo, 1);
+}
+
+void init_basic_merge_options(struct merge_options *opt,
+			struct repository *repo)
+{
+	init_merge_options(opt, repo, 0);
+}
+
+/*
+ * For now, members of merge_options do not need deep copying, but
+ * it may change in the future, in which case we would need to update
+ * this, and also make a matching change to clear_merge_options() to
+ * release the resources held by a copied instance.
+ */
+void copy_merge_options(struct merge_options *dst, struct merge_options *src)
+{
+	*dst = *src;
+}
+
+void clear_merge_options(struct merge_options *opt UNUSED)
+{
+	; /* no-op as our copy is shallow right now */
+}
+
+int parse_merge_opt(struct merge_options *opt, const char *s)
+{
+	const char *arg;
+
+	if (!s || !*s)
+		return -1;
+	if (!strcmp(s, "ours"))
+		opt->recursive_variant = MERGE_VARIANT_OURS;
+	else if (!strcmp(s, "theirs"))
+		opt->recursive_variant = MERGE_VARIANT_THEIRS;
+	else if (!strcmp(s, "subtree"))
+		opt->subtree_shift = "";
+	else if (skip_prefix(s, "subtree=", &arg))
+		opt->subtree_shift = arg;
+	else if (!strcmp(s, "patience"))
+		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
+	else if (!strcmp(s, "histogram"))
+		opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
+	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
+		long value = parse_algorithm_value(arg);
+		if (value < 0)
+			return -1;
+		/* clear out previous settings */
+		DIFF_XDL_CLR(opt, NEED_MINIMAL);
+		opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
+		opt->xdl_opts |= value;
+	}
+	else if (!strcmp(s, "ignore-space-change"))
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
+	else if (!strcmp(s, "ignore-all-space"))
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
+	else if (!strcmp(s, "ignore-space-at-eol"))
+		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
+	else if (!strcmp(s, "ignore-cr-at-eol"))
+		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
+	else if (!strcmp(s, "renormalize"))
+		opt->renormalize = 1;
+	else if (!strcmp(s, "no-renormalize"))
+		opt->renormalize = 0;
+	else if (!strcmp(s, "no-renames"))
+		opt->detect_renames = 0;
+	else if (!strcmp(s, "find-renames")) {
+		opt->detect_renames = 1;
+		opt->rename_score = 0;
+	}
+	else if (skip_prefix(s, "find-renames=", &arg) ||
+		 skip_prefix(s, "rename-threshold=", &arg)) {
+		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
+			return -1;
+		opt->detect_renames = 1;
+	}
+	/*
+	 * Please update $__git_merge_strategy_options in
+	 * git-completion.bash when you add new options
+	 */
+	else
+		return -1;
+	return 0;
+}
diff --git a/merge-ort.h b/merge-ort.h
index b63bc5424e7..30750c03962 100644
--- a/merge-ort.h
+++ b/merge-ort.h
@@ -1,10 +1,11 @@
 #ifndef MERGE_ORT_H
 #define MERGE_ORT_H
 
-#include "merge-recursive.h"
 #include "hash.h"
+#include "strbuf.h"
 
 struct commit;
+struct commit_list;
 struct tree;
 struct strmap;
 
@@ -44,6 +45,51 @@ struct merge_result {
 	unsigned _properly_initialized;
 };
 
+struct merge_options_internal;
+struct merge_options {
+	struct repository *repo;
+
+	/* ref names used in console messages and conflict markers */
+	const char *ancestor;
+	const char *branch1;
+	const char *branch2;
+
+	/* rename related options */
+	int detect_renames;
+	enum {
+		MERGE_DIRECTORY_RENAMES_NONE = 0,
+		MERGE_DIRECTORY_RENAMES_CONFLICT = 1,
+		MERGE_DIRECTORY_RENAMES_TRUE = 2
+	} detect_directory_renames;
+	int rename_limit;
+	int rename_score;
+	int show_rename_progress;
+
+	/* xdiff-related options (patience, ignore whitespace, ours/theirs) */
+	long xdl_opts;
+	int conflict_style;
+	enum {
+		MERGE_VARIANT_NORMAL = 0,
+		MERGE_VARIANT_OURS,
+		MERGE_VARIANT_THEIRS
+	} recursive_variant;
+
+	/* console output related options */
+	int verbosity;
+	unsigned buffer_output; /* 1: output at end, 2: keep buffered */
+	struct strbuf obuf;     /* output buffer; if buffer_output == 2, caller
+				 * must handle and call strbuf_release */
+
+	/* miscellaneous control options */
+	const char *subtree_shift;
+	unsigned renormalize : 1;
+	unsigned record_conflict_msgs_as_headers : 1;
+	const char *msg_header_prefix;
+
+	/* internal fields used by the implementation */
+	struct merge_options_internal *priv;
+};
+
 /* Mostly internal function also used by merge-ort-wrappers.c */
 struct commit *make_virtual_commit(struct repository *repo,
 				   struct tree *tree,
@@ -119,4 +165,16 @@ void merge_get_conflicted_files(struct merge_result *result,
 void merge_finalize(struct merge_options *opt,
 		    struct merge_result *result);
 
+
+/* for use by porcelain commands */
+void init_ui_merge_options(struct merge_options *opt, struct repository *repo);
+/* for use by plumbing commands */
+void init_basic_merge_options(struct merge_options *opt, struct repository *repo);
+
+void copy_merge_options(struct merge_options *dst, struct merge_options *src);
+void clear_merge_options(struct merge_options *opt);
+
+/* parse the option in s and update the relevant field of opt */
+int parse_merge_opt(struct merge_options *opt, const char *s);
+
 #endif
diff --git a/merge-recursive.c b/merge-recursive.c
deleted file mode 100644
index f3df127ad9b..00000000000
--- a/merge-recursive.c
+++ /dev/null
@@ -1,4080 +0,0 @@
-/*
- * Recursive Merge algorithm stolen from git-merge-recursive.py by
- * Fredrik Kuivinen.
- * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
- */
-
-#define USE_THE_REPOSITORY_VARIABLE
-#define DISABLE_SIGN_COMPARE_WARNINGS
-
-#include "git-compat-util.h"
-#include "merge-recursive.h"
-
-#include "alloc.h"
-#include "cache-tree.h"
-#include "commit.h"
-#include "commit-reach.h"
-#include "config.h"
-#include "diff.h"
-#include "diffcore.h"
-#include "dir.h"
-#include "environment.h"
-#include "gettext.h"
-#include "hex.h"
-#include "merge-ll.h"
-#include "lockfile.h"
-#include "match-trees.h"
-#include "name-hash.h"
-#include "object-file.h"
-#include "object-name.h"
-#include "object-store-ll.h"
-#include "path.h"
-#include "repository.h"
-#include "revision.h"
-#include "sparse-index.h"
-#include "string-list.h"
-#include "symlinks.h"
-#include "tag.h"
-#include "tree-walk.h"
-#include "unpack-trees.h"
-#include "xdiff-interface.h"
-
-struct merge_options_internal {
-	int call_depth;
-	int needed_rename_limit;
-	struct hashmap current_file_dir_set;
-	struct string_list df_conflict_file_set;
-	struct unpack_trees_options unpack_opts;
-	struct index_state orig_index;
-};
-
-struct path_hashmap_entry {
-	struct hashmap_entry e;
-	char path[FLEX_ARRAY];
-};
-
-static int path_hashmap_cmp(const void *cmp_data UNUSED,
-			    const struct hashmap_entry *eptr,
-			    const struct hashmap_entry *entry_or_key,
-			    const void *keydata)
-{
-	const struct path_hashmap_entry *a, *b;
-	const char *key = keydata;
-
-	a = container_of(eptr, const struct path_hashmap_entry, e);
-	b = container_of(entry_or_key, const struct path_hashmap_entry, e);
-
-	return fspathcmp(a->path, key ? key : b->path);
-}
-
-/*
- * For dir_rename_entry, directory names are stored as a full path from the
- * toplevel of the repository and do not include a trailing '/'.  Also:
- *
- *   dir:                original name of directory being renamed
- *   non_unique_new_dir: if true, could not determine new_dir
- *   new_dir:            final name of directory being renamed
- *   possible_new_dirs:  temporary used to help determine new_dir; see comments
- *                       in get_directory_renames() for details
- */
-struct dir_rename_entry {
-	struct hashmap_entry ent;
-	char *dir;
-	unsigned non_unique_new_dir:1;
-	struct strbuf new_dir;
-	struct string_list possible_new_dirs;
-};
-
-static struct dir_rename_entry *dir_rename_find_entry(struct hashmap *hashmap,
-						      char *dir)
-{
-	struct dir_rename_entry key;
-
-	if (!dir)
-		return NULL;
-	hashmap_entry_init(&key.ent, strhash(dir));
-	key.dir = dir;
-	return hashmap_get_entry(hashmap, &key, ent, NULL);
-}
-
-static int dir_rename_cmp(const void *cmp_data UNUSED,
-			  const struct hashmap_entry *eptr,
-			  const struct hashmap_entry *entry_or_key,
-			  const void *keydata UNUSED)
-{
-	const struct dir_rename_entry *e1, *e2;
-
-	e1 = container_of(eptr, const struct dir_rename_entry, ent);
-	e2 = container_of(entry_or_key, const struct dir_rename_entry, ent);
-
-	return strcmp(e1->dir, e2->dir);
-}
-
-static void dir_rename_init(struct hashmap *map)
-{
-	hashmap_init(map, dir_rename_cmp, NULL, 0);
-}
-
-static void dir_rename_entry_init(struct dir_rename_entry *entry,
-				  char *directory)
-{
-	hashmap_entry_init(&entry->ent, strhash(directory));
-	entry->dir = directory;
-	entry->non_unique_new_dir = 0;
-	strbuf_init(&entry->new_dir, 0);
-	string_list_init_nodup(&entry->possible_new_dirs);
-}
-
-struct collision_entry {
-	struct hashmap_entry ent;
-	char *target_file;
-	struct string_list source_files;
-	unsigned reported_already:1;
-};
-
-static struct collision_entry *collision_find_entry(struct hashmap *hashmap,
-						    char *target_file)
-{
-	struct collision_entry key;
-
-	hashmap_entry_init(&key.ent, strhash(target_file));
-	key.target_file = target_file;
-	return hashmap_get_entry(hashmap, &key, ent, NULL);
-}
-
-static int collision_cmp(const void *cmp_data UNUSED,
-			 const struct hashmap_entry *eptr,
-			 const struct hashmap_entry *entry_or_key,
-			 const void *keydata UNUSED)
-{
-	const struct collision_entry *e1, *e2;
-
-	e1 = container_of(eptr, const struct collision_entry, ent);
-	e2 = container_of(entry_or_key, const struct collision_entry, ent);
-
-	return strcmp(e1->target_file, e2->target_file);
-}
-
-static void collision_init(struct hashmap *map)
-{
-	hashmap_init(map, collision_cmp, NULL, 0);
-}
-
-static void flush_output(struct merge_options *opt)
-{
-	if (opt->buffer_output < 2 && opt->obuf.len) {
-		fputs(opt->obuf.buf, stdout);
-		strbuf_reset(&opt->obuf);
-	}
-}
-
-__attribute__((format (printf, 2, 3)))
-static int err(struct merge_options *opt, const char *err, ...)
-{
-	va_list params;
-
-	if (opt->buffer_output < 2)
-		flush_output(opt);
-	else {
-		strbuf_complete(&opt->obuf, '\n');
-		strbuf_addstr(&opt->obuf, "error: ");
-	}
-	va_start(params, err);
-	strbuf_vaddf(&opt->obuf, err, params);
-	va_end(params);
-	if (opt->buffer_output > 1)
-		strbuf_addch(&opt->obuf, '\n');
-	else {
-		error("%s", opt->obuf.buf);
-		strbuf_reset(&opt->obuf);
-	}
-
-	return -1;
-}
-
-static struct tree *shift_tree_object(struct repository *repo,
-				      struct tree *one, struct tree *two,
-				      const char *subtree_shift)
-{
-	struct object_id shifted;
-
-	if (!*subtree_shift) {
-		shift_tree(repo, &one->object.oid, &two->object.oid, &shifted, 0);
-	} else {
-		shift_tree_by(repo, &one->object.oid, &two->object.oid, &shifted,
-			      subtree_shift);
-	}
-	if (oideq(&two->object.oid, &shifted))
-		return two;
-	return lookup_tree(repo, &shifted);
-}
-
-static inline void set_commit_tree(struct commit *c, struct tree *t)
-{
-	c->maybe_tree = t;
-}
-
-static struct commit *make_virtual_commit(struct repository *repo,
-					  struct tree *tree,
-					  const char *comment)
-{
-	struct commit *commit = alloc_commit_node(repo);
-
-	set_merge_remote_desc(commit, comment, (struct object *)commit);
-	set_commit_tree(commit, tree);
-	commit->object.parsed = 1;
-	return commit;
-}
-
-enum rename_type {
-	RENAME_NORMAL = 0,
-	RENAME_VIA_DIR,
-	RENAME_ADD,
-	RENAME_DELETE,
-	RENAME_ONE_FILE_TO_ONE,
-	RENAME_ONE_FILE_TO_TWO,
-	RENAME_TWO_FILES_TO_ONE
-};
-
-/*
- * Since we want to write the index eventually, we cannot reuse the index
- * for these (temporary) data.
- */
-struct stage_data {
-	struct diff_filespec stages[4]; /* mostly for oid & mode; maybe path */
-	struct rename_conflict_info *rename_conflict_info;
-	unsigned processed:1,
-		 rename_conflict_info_owned:1;
-};
-
-struct rename {
-	unsigned processed:1;
-	struct diff_filepair *pair;
-	const char *branch; /* branch that the rename occurred on */
-	/*
-	 * If directory rename detection affected this rename, what was its
-	 * original type ('A' or 'R') and it's original destination before
-	 * the directory rename (otherwise, '\0' and NULL for these two vars).
-	 */
-	char dir_rename_original_type;
-	char *dir_rename_original_dest;
-	/*
-	 * Purpose of src_entry and dst_entry:
-	 *
-	 * If 'before' is renamed to 'after' then src_entry will contain
-	 * the versions of 'before' from the merge_base, HEAD, and MERGE in
-	 * stages 1, 2, and 3; dst_entry will contain the respective
-	 * versions of 'after' in corresponding locations.  Thus, we have a
-	 * total of six modes and oids, though some will be null.  (Stage 0
-	 * is ignored; we're interested in handling conflicts.)
-	 *
-	 * Since we don't turn on break-rewrites by default, neither
-	 * src_entry nor dst_entry can have all three of their stages have
-	 * non-null oids, meaning at most four of the six will be non-null.
-	 * Also, since this is a rename, both src_entry and dst_entry will
-	 * have at least one non-null oid, meaning at least two will be
-	 * non-null.  Of the six oids, a typical rename will have three be
-	 * non-null.  Only two implies a rename/delete, and four implies a
-	 * rename/add.
-	 */
-	struct stage_data *src_entry;
-	struct stage_data *dst_entry;
-};
-
-struct rename_conflict_info {
-	enum rename_type rename_type;
-	struct rename *ren1;
-	struct rename *ren2;
-};
-
-static inline void setup_rename_conflict_info(enum rename_type rename_type,
-					      struct merge_options *opt,
-					      struct rename *ren1,
-					      struct rename *ren2)
-{
-	struct rename_conflict_info *ci;
-
-	/*
-	 * When we have two renames involved, it's easiest to get the
-	 * correct things into stage 2 and 3, and to make sure that the
-	 * content merge puts HEAD before the other branch if we just
-	 * ensure that branch1 == opt->branch1.  So, simply flip arguments
-	 * around if we don't have that.
-	 */
-	if (ren2 && ren1->branch != opt->branch1) {
-		setup_rename_conflict_info(rename_type, opt, ren2, ren1);
-		return;
-	}
-
-	CALLOC_ARRAY(ci, 1);
-	ci->rename_type = rename_type;
-	ci->ren1 = ren1;
-	ci->ren2 = ren2;
-
-	ci->ren1->dst_entry->processed = 0;
-	ci->ren1->dst_entry->rename_conflict_info = ci;
-	ci->ren1->dst_entry->rename_conflict_info_owned = 1;
-	if (ren2) {
-		ci->ren2->dst_entry->rename_conflict_info = ci;
-	}
-}
-
-static int show(struct merge_options *opt, int v)
-{
-	return (!opt->priv->call_depth && opt->verbosity >= v) ||
-		opt->verbosity >= 5;
-}
-
-__attribute__((format (printf, 3, 4)))
-static void output(struct merge_options *opt, int v, const char *fmt, ...)
-{
-	va_list ap;
-
-	if (!show(opt, v))
-		return;
-
-	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);
-
-	va_start(ap, fmt);
-	strbuf_vaddf(&opt->obuf, fmt, ap);
-	va_end(ap);
-
-	strbuf_addch(&opt->obuf, '\n');
-	if (!opt->buffer_output)
-		flush_output(opt);
-}
-
-static void repo_output_commit_title(struct merge_options *opt,
-				     struct repository *repo,
-				     struct commit *commit)
-{
-	struct merge_remote_desc *desc;
-
-	strbuf_addchars(&opt->obuf, ' ', opt->priv->call_depth * 2);
-	desc = merge_remote_util(commit);
-	if (desc)
-		strbuf_addf(&opt->obuf, "virtual %s\n", desc->name);
-	else {
-		strbuf_repo_add_unique_abbrev(&opt->obuf, repo,
-					      &commit->object.oid,
-					      DEFAULT_ABBREV);
-		strbuf_addch(&opt->obuf, ' ');
-		if (repo_parse_commit(repo, commit) != 0)
-			strbuf_addstr(&opt->obuf, _("(bad commit)\n"));
-		else {
-			const char *title;
-			const char *msg = repo_get_commit_buffer(repo, commit, NULL);
-			int len = find_commit_subject(msg, &title);
-			if (len)
-				strbuf_addf(&opt->obuf, "%.*s\n", len, title);
-			repo_unuse_commit_buffer(repo, commit, msg);
-		}
-	}
-	flush_output(opt);
-}
-
-static void output_commit_title(struct merge_options *opt, struct commit *commit)
-{
-	repo_output_commit_title(opt, the_repository, commit);
-}
-
-static int add_cacheinfo(struct merge_options *opt,
-			 const struct diff_filespec *blob,
-			 const char *path, int stage, int refresh, int options)
-{
-	struct index_state *istate = opt->repo->index;
-	struct cache_entry *ce;
-	int ret;
-
-	ce = make_cache_entry(istate, blob->mode, &blob->oid, path, stage, 0);
-	if (!ce)
-		return err(opt, _("add_cacheinfo failed for path '%s'; merge aborting."), path);
-
-	ret = add_index_entry(istate, ce, options);
-	if (refresh) {
-		struct cache_entry *nce;
-
-		nce = refresh_cache_entry(istate, ce,
-					  CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
-		if (!nce)
-			return err(opt, _("add_cacheinfo failed to refresh for path '%s'; merge aborting."), path);
-		if (nce != ce)
-			ret = add_index_entry(istate, nce, options);
-	}
-	return ret;
-}
-
-static inline int merge_detect_rename(struct merge_options *opt)
-{
-	return (opt->detect_renames >= 0) ? opt->detect_renames : 1;
-}
-
-static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
-{
-	if (parse_tree(tree) < 0)
-		exit(128);
-	init_tree_desc(desc, &tree->object.oid, tree->buffer, tree->size);
-}
-
-static int unpack_trees_start(struct merge_options *opt,
-			      struct tree *common,
-			      struct tree *head,
-			      struct tree *merge)
-{
-	int rc;
-	struct tree_desc t[3];
-	struct index_state tmp_index = INDEX_STATE_INIT(opt->repo);
-
-	memset(&opt->priv->unpack_opts, 0, sizeof(opt->priv->unpack_opts));
-	if (opt->priv->call_depth)
-		opt->priv->unpack_opts.index_only = 1;
-	else {
-		opt->priv->unpack_opts.update = 1;
-		/* FIXME: should only do this if !overwrite_ignore */
-		opt->priv->unpack_opts.preserve_ignored = 0;
-	}
-	opt->priv->unpack_opts.merge = 1;
-	opt->priv->unpack_opts.head_idx = 2;
-	opt->priv->unpack_opts.fn = threeway_merge;
-	opt->priv->unpack_opts.src_index = opt->repo->index;
-	opt->priv->unpack_opts.dst_index = &tmp_index;
-	opt->priv->unpack_opts.aggressive = !merge_detect_rename(opt);
-	setup_unpack_trees_porcelain(&opt->priv->unpack_opts, "merge");
-
-	init_tree_desc_from_tree(t+0, common);
-	init_tree_desc_from_tree(t+1, head);
-	init_tree_desc_from_tree(t+2, merge);
-
-	rc = unpack_trees(3, t, &opt->priv->unpack_opts);
-	cache_tree_free(&opt->repo->index->cache_tree);
-
-	/*
-	 * Update opt->repo->index to match the new results, AFTER saving a
-	 * copy in opt->priv->orig_index.  Update src_index to point to the
-	 * saved copy.  (verify_uptodate() checks src_index, and the original
-	 * index is the one that had the necessary modification timestamps.)
-	 */
-	opt->priv->orig_index = *opt->repo->index;
-	*opt->repo->index = tmp_index;
-	opt->priv->unpack_opts.src_index = &opt->priv->orig_index;
-
-	return rc;
-}
-
-static void unpack_trees_finish(struct merge_options *opt)
-{
-	discard_index(&opt->priv->orig_index);
-	clear_unpack_trees_porcelain(&opt->priv->unpack_opts);
-}
-
-static int save_files_dirs(const struct object_id *oid UNUSED,
-			   struct strbuf *base, const char *path,
-			   unsigned int mode, void *context)
-{
-	struct path_hashmap_entry *entry;
-	int baselen = base->len;
-	struct merge_options *opt = context;
-
-	strbuf_addstr(base, path);
-
-	FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
-	hashmap_entry_init(&entry->e, fspathhash(entry->path));
-	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
-
-	strbuf_setlen(base, baselen);
-	return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
-}
-
-static void get_files_dirs(struct merge_options *opt, struct tree *tree)
-{
-	struct pathspec match_all;
-	memset(&match_all, 0, sizeof(match_all));
-	read_tree(opt->repo, tree,
-		  &match_all, save_files_dirs, opt);
-}
-
-static int get_tree_entry_if_blob(struct repository *r,
-				  const struct object_id *tree,
-				  const char *path,
-				  struct diff_filespec *dfs)
-{
-	int ret;
-
-	ret = get_tree_entry(r, tree, path, &dfs->oid, &dfs->mode);
-	if (S_ISDIR(dfs->mode)) {
-		oidcpy(&dfs->oid, null_oid());
-		dfs->mode = 0;
-	}
-	return ret;
-}
-
-/*
- * Returns an index_entry instance which doesn't have to correspond to
- * a real cache entry in Git's index.
- */
-static struct stage_data *insert_stage_data(struct repository *r,
-		const char *path,
-		struct tree *o, struct tree *a, struct tree *b,
-		struct string_list *entries)
-{
-	struct string_list_item *item;
-	struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
-	get_tree_entry_if_blob(r, &o->object.oid, path, &e->stages[1]);
-	get_tree_entry_if_blob(r, &a->object.oid, path, &e->stages[2]);
-	get_tree_entry_if_blob(r, &b->object.oid, path, &e->stages[3]);
-	item = string_list_insert(entries, path);
-	item->util = e;
-	return e;
-}
-
-/*
- * Create a dictionary mapping file names to stage_data objects. The
- * dictionary contains one entry for every path with a non-zero stage entry.
- */
-static struct string_list *get_unmerged(struct index_state *istate)
-{
-	struct string_list *unmerged = xmalloc(sizeof(struct string_list));
-	int i;
-
-	string_list_init_dup(unmerged);
-
-	/* TODO: audit for interaction with sparse-index. */
-	ensure_full_index(istate);
-	for (i = 0; i < istate->cache_nr; i++) {
-		struct string_list_item *item;
-		struct stage_data *e;
-		const struct cache_entry *ce = istate->cache[i];
-		if (!ce_stage(ce))
-			continue;
-
-		item = string_list_lookup(unmerged, ce->name);
-		if (!item) {
-			item = string_list_insert(unmerged, ce->name);
-			item->util = xcalloc(1, sizeof(struct stage_data));
-		}
-		e = item->util;
-		e->stages[ce_stage(ce)].mode = ce->ce_mode;
-		oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
-	}
-
-	return unmerged;
-}
-
-static int string_list_df_name_compare(const char *one, const char *two)
-{
-	int onelen = strlen(one);
-	int twolen = strlen(two);
-	/*
-	 * Here we only care that entries for D/F conflicts are
-	 * adjacent, in particular with the file of the D/F conflict
-	 * appearing before files below the corresponding directory.
-	 * The order of the rest of the list is irrelevant for us.
-	 *
-	 * To achieve this, we sort with df_name_compare and provide
-	 * the mode S_IFDIR so that D/F conflicts will sort correctly.
-	 * We use the mode S_IFDIR for everything else for simplicity,
-	 * since in other cases any changes in their order due to
-	 * sorting cause no problems for us.
-	 */
-	int cmp = df_name_compare(one, onelen, S_IFDIR,
-				  two, twolen, S_IFDIR);
-	/*
-	 * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
-	 * that 'foo' comes before 'foo/bar'.
-	 */
-	if (cmp)
-		return cmp;
-	return onelen - twolen;
-}
-
-static void record_df_conflict_files(struct merge_options *opt,
-				     struct string_list *entries)
-{
-	/* If there is a D/F conflict and the file for such a conflict
-	 * currently exists in the working tree, we want to allow it to be
-	 * removed to make room for the corresponding directory if needed.
-	 * The files underneath the directories of such D/F conflicts will
-	 * be processed before the corresponding file involved in the D/F
-	 * conflict.  If the D/F directory ends up being removed by the
-	 * merge, then we won't have to touch the D/F file.  If the D/F
-	 * directory needs to be written to the working copy, then the D/F
-	 * file will simply be removed (in make_room_for_path()) to make
-	 * room for the necessary paths.  Note that if both the directory
-	 * and the file need to be present, then the D/F file will be
-	 * reinstated with a new unique name at the time it is processed.
-	 */
-	struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
-	const char *last_file = NULL;
-	int last_len = 0;
-	int i;
-
-	/*
-	 * If we're merging merge-bases, we don't want to bother with
-	 * any working directory changes.
-	 */
-	if (opt->priv->call_depth)
-		return;
-
-	/* Ensure D/F conflicts are adjacent in the entries list. */
-	for (i = 0; i < entries->nr; i++) {
-		struct string_list_item *next = &entries->items[i];
-		string_list_append(&df_sorted_entries, next->string)->util =
-				   next->util;
-	}
-	df_sorted_entries.cmp = string_list_df_name_compare;
-	string_list_sort(&df_sorted_entries);
-
-	string_list_clear(&opt->priv->df_conflict_file_set, 1);
-	for (i = 0; i < df_sorted_entries.nr; i++) {
-		const char *path = df_sorted_entries.items[i].string;
-		int len = strlen(path);
-		struct stage_data *e = df_sorted_entries.items[i].util;
-
-		/*
-		 * Check if last_file & path correspond to a D/F conflict;
-		 * i.e. whether path is last_file+'/'+<something>.
-		 * If so, record that it's okay to remove last_file to make
-		 * room for path and friends if needed.
-		 */
-		if (last_file &&
-		    len > last_len &&
-		    memcmp(path, last_file, last_len) == 0 &&
-		    path[last_len] == '/') {
-			string_list_insert(&opt->priv->df_conflict_file_set, last_file);
-		}
-
-		/*
-		 * Determine whether path could exist as a file in the
-		 * working directory as a possible D/F conflict.  This
-		 * will only occur when it exists in stage 2 as a
-		 * file.
-		 */
-		if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
-			last_file = path;
-			last_len = len;
-		} else {
-			last_file = NULL;
-		}
-	}
-	string_list_clear(&df_sorted_entries, 0);
-}
-
-static int update_stages(struct merge_options *opt, const char *path,
-			 const struct diff_filespec *o,
-			 const struct diff_filespec *a,
-			 const struct diff_filespec *b)
-{
-
-	/*
-	 * NOTE: It is usually a bad idea to call update_stages on a path
-	 * before calling update_file on that same path, since it can
-	 * sometimes lead to spurious "refusing to lose untracked file..."
-	 * messages from update_file (via make_room_for path via
-	 * would_lose_untracked).  Instead, reverse the order of the calls
-	 * (executing update_file first and then update_stages).
-	 */
-	int clear = 1;
-	int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
-	if (clear)
-		if (remove_file_from_index(opt->repo->index, path))
-			return -1;
-	if (o)
-		if (add_cacheinfo(opt, o, path, 1, 0, options))
-			return -1;
-	if (a)
-		if (add_cacheinfo(opt, a, path, 2, 0, options))
-			return -1;
-	if (b)
-		if (add_cacheinfo(opt, b, path, 3, 0, options))
-			return -1;
-	return 0;
-}
-
-static void update_entry(struct stage_data *entry,
-			 struct diff_filespec *o,
-			 struct diff_filespec *a,
-			 struct diff_filespec *b)
-{
-	entry->processed = 0;
-	entry->stages[1].mode = o->mode;
-	entry->stages[2].mode = a->mode;
-	entry->stages[3].mode = b->mode;
-	oidcpy(&entry->stages[1].oid, &o->oid);
-	oidcpy(&entry->stages[2].oid, &a->oid);
-	oidcpy(&entry->stages[3].oid, &b->oid);
-}
-
-static int remove_file(struct merge_options *opt, int clean,
-		       const char *path, int no_wd)
-{
-	int update_cache = opt->priv->call_depth || clean;
-	int update_working_directory = !opt->priv->call_depth && !no_wd;
-
-	if (update_cache) {
-		if (remove_file_from_index(opt->repo->index, path))
-			return -1;
-	}
-	if (update_working_directory) {
-		if (ignore_case) {
-			struct cache_entry *ce;
-			ce = index_file_exists(opt->repo->index, path, strlen(path),
-					       ignore_case);
-			if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
-				return 0;
-		}
-		if (remove_path(path))
-			return -1;
-	}
-	return 0;
-}
-
-/* add a string to a strbuf, but converting "/" to "_" */
-static void add_flattened_path(struct strbuf *out, const char *s)
-{
-	size_t i = out->len;
-	strbuf_addstr(out, s);
-	for (; i < out->len; i++)
-		if (out->buf[i] == '/')
-			out->buf[i] = '_';
-}
-
-static char *unique_path(struct merge_options *opt,
-			 const char *path,
-			 const char *branch)
-{
-	struct path_hashmap_entry *entry;
-	struct strbuf newpath = STRBUF_INIT;
-	int suffix = 0;
-	size_t base_len;
-
-	strbuf_addf(&newpath, "%s~", path);
-	add_flattened_path(&newpath, branch);
-
-	base_len = newpath.len;
-	while (hashmap_get_from_hash(&opt->priv->current_file_dir_set,
-				     fspathhash(newpath.buf), newpath.buf) ||
-	       (!opt->priv->call_depth && file_exists(newpath.buf))) {
-		strbuf_setlen(&newpath, base_len);
-		strbuf_addf(&newpath, "_%d", suffix++);
-	}
-
-	FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
-	hashmap_entry_init(&entry->e, fspathhash(entry->path));
-	hashmap_add(&opt->priv->current_file_dir_set, &entry->e);
-	return strbuf_detach(&newpath, NULL);
-}
-
-/**
- * Check whether a directory in the index is in the way of an incoming
- * file.  Return 1 if so.  If check_working_copy is non-zero, also
- * check the working directory.  If empty_ok is non-zero, also return
- * 0 in the case where the working-tree dir exists but is empty.
- */
-static int dir_in_way(struct index_state *istate, const char *path,
-		      int check_working_copy, int empty_ok)
-{
-	int pos;
-	struct strbuf dirpath = STRBUF_INIT;
-	struct stat st;
-
-	strbuf_addstr(&dirpath, path);
-	strbuf_addch(&dirpath, '/');
-
-	pos = index_name_pos(istate, dirpath.buf, dirpath.len);
-
-	if (pos < 0)
-		pos = -1 - pos;
-	if (pos < istate->cache_nr &&
-	    !strncmp(dirpath.buf, istate->cache[pos]->name, dirpath.len)) {
-		strbuf_release(&dirpath);
-		return 1;
-	}
-
-	strbuf_release(&dirpath);
-	return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
-		!(empty_ok && is_empty_dir(path)) &&
-		!has_symlink_leading_path(path, strlen(path));
-}
-
-/*
- * Returns whether path was tracked in the index before the merge started,
- * and its oid and mode match the specified values
- */
-static int was_tracked_and_matches(struct merge_options *opt, const char *path,
-				   const struct diff_filespec *blob)
-{
-	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
-	struct cache_entry *ce;
-
-	if (0 > pos)
-		/* we were not tracking this path before the merge */
-		return 0;
-
-	/* See if the file we were tracking before matches */
-	ce = opt->priv->orig_index.cache[pos];
-	return (oideq(&ce->oid, &blob->oid) && ce->ce_mode == blob->mode);
-}
-
-/*
- * Returns whether path was tracked in the index before the merge started
- */
-static int was_tracked(struct merge_options *opt, const char *path)
-{
-	int pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
-
-	if (0 <= pos)
-		/* we were tracking this path before the merge */
-		return 1;
-
-	return 0;
-}
-
-static int would_lose_untracked(struct merge_options *opt, const char *path)
-{
-	struct index_state *istate = opt->repo->index;
-
-	/*
-	 * This may look like it can be simplified to:
-	 *   return !was_tracked(opt, path) && file_exists(path)
-	 * but it can't.  This function needs to know whether path was in
-	 * the working tree due to EITHER having been tracked in the index
-	 * before the merge OR having been put into the working copy and
-	 * index by unpack_trees().  Due to that either-or requirement, we
-	 * check the current index instead of the original one.
-	 *
-	 * Note that we do not need to worry about merge-recursive itself
-	 * updating the index after unpack_trees() and before calling this
-	 * function, because we strictly require all code paths in
-	 * merge-recursive to update the working tree first and the index
-	 * second.  Doing otherwise would break
-	 * update_file()/would_lose_untracked(); see every comment in this
-	 * file which mentions "update_stages".
-	 */
-	int pos = index_name_pos(istate, path, strlen(path));
-
-	if (pos < 0)
-		pos = -1 - pos;
-	while (pos < istate->cache_nr &&
-	       !strcmp(path, istate->cache[pos]->name)) {
-		/*
-		 * If stage #0, it is definitely tracked.
-		 * If it has stage #2 then it was tracked
-		 * before this merge started.  All other
-		 * cases the path was not tracked.
-		 */
-		switch (ce_stage(istate->cache[pos])) {
-		case 0:
-		case 2:
-			return 0;
-		}
-		pos++;
-	}
-	return file_exists(path);
-}
-
-static int was_dirty(struct merge_options *opt, const char *path)
-{
-	struct cache_entry *ce;
-	int dirty = 1;
-
-	if (opt->priv->call_depth || !was_tracked(opt, path))
-		return !dirty;
-
-	ce = index_file_exists(opt->priv->unpack_opts.src_index,
-			       path, strlen(path), ignore_case);
-	dirty = verify_uptodate(ce, &opt->priv->unpack_opts) != 0;
-	return dirty;
-}
-
-static int make_room_for_path(struct merge_options *opt, const char *path)
-{
-	int status, i;
-	const char *msg = _("failed to create path '%s'%s");
-
-	/* Unlink any D/F conflict files that are in the way */
-	for (i = 0; i < opt->priv->df_conflict_file_set.nr; i++) {
-		const char *df_path = opt->priv->df_conflict_file_set.items[i].string;
-		size_t pathlen = strlen(path);
-		size_t df_pathlen = strlen(df_path);
-		if (df_pathlen < pathlen &&
-		    path[df_pathlen] == '/' &&
-		    strncmp(path, df_path, df_pathlen) == 0) {
-			output(opt, 3,
-			       _("Removing %s to make room for subdirectory\n"),
-			       df_path);
-			unlink(df_path);
-			unsorted_string_list_delete_item(&opt->priv->df_conflict_file_set,
-							 i, 0);
-			break;
-		}
-	}
-
-	/* Make sure leading directories are created */
-	status = safe_create_leading_directories_const(path);
-	if (status) {
-		if (status == SCLD_EXISTS)
-			/* something else exists */
-			return err(opt, msg, path, _(": perhaps a D/F conflict?"));
-		return err(opt, msg, path, "");
-	}
-
-	/*
-	 * Do not unlink a file in the work tree if we are not
-	 * tracking it.
-	 */
-	if (would_lose_untracked(opt, path))
-		return err(opt, _("refusing to lose untracked file at '%s'"),
-			   path);
-
-	/* Successful unlink is good.. */
-	if (!unlink(path))
-		return 0;
-	/* .. and so is no existing file */
-	if (errno == ENOENT)
-		return 0;
-	/* .. but not some other error (who really cares what?) */
-	return err(opt, msg, path, _(": perhaps a D/F conflict?"));
-}
-
-static int update_file_flags(struct merge_options *opt,
-			     const struct diff_filespec *contents,
-			     const char *path,
-			     int update_cache,
-			     int update_wd)
-{
-	int ret = 0;
-
-	if (opt->priv->call_depth)
-		update_wd = 0;
-
-	if (update_wd) {
-		enum object_type type;
-		void *buf;
-		unsigned long size;
-
-		if (S_ISGITLINK(contents->mode)) {
-			/*
-			 * We may later decide to recursively descend into
-			 * the submodule directory and update its index
-			 * and/or work tree, but we do not do that now.
-			 */
-			update_wd = 0;
-			goto update_index;
-		}
-
-		buf = repo_read_object_file(the_repository, &contents->oid,
-					    &type, &size);
-		if (!buf) {
-			ret = err(opt, _("cannot read object %s '%s'"),
-				  oid_to_hex(&contents->oid), path);
-			goto free_buf;
-		}
-		if (type != OBJ_BLOB) {
-			ret = err(opt, _("blob expected for %s '%s'"),
-				  oid_to_hex(&contents->oid), path);
-			goto free_buf;
-		}
-		if (S_ISREG(contents->mode)) {
-			struct strbuf strbuf = STRBUF_INIT;
-			if (convert_to_working_tree(opt->repo->index,
-						    path, buf, size, &strbuf, NULL)) {
-				free(buf);
-				size = strbuf.len;
-				buf = strbuf_detach(&strbuf, NULL);
-			}
-		}
-
-		if (make_room_for_path(opt, path) < 0) {
-			update_wd = 0;
-			goto free_buf;
-		}
-		if (S_ISREG(contents->mode) ||
-		    (!has_symlinks && S_ISLNK(contents->mode))) {
-			int fd;
-			int mode = (contents->mode & 0100 ? 0777 : 0666);
-
-			fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
-			if (fd < 0) {
-				ret = err(opt, _("failed to open '%s': %s"),
-					  path, strerror(errno));
-				goto free_buf;
-			}
-			write_in_full(fd, buf, size);
-			close(fd);
-		} else if (S_ISLNK(contents->mode)) {
-			char *lnk = xmemdupz(buf, size);
-			safe_create_leading_directories_const(path);
-			unlink(path);
-			if (symlink(lnk, path))
-				ret = err(opt, _("failed to symlink '%s': %s"),
-					  path, strerror(errno));
-			free(lnk);
-		} else
-			ret = err(opt,
-				  _("do not know what to do with %06o %s '%s'"),
-				  contents->mode, oid_to_hex(&contents->oid), path);
-	free_buf:
-		free(buf);
-	}
-update_index:
-	if (!ret && update_cache) {
-		int refresh = (!opt->priv->call_depth &&
-			       contents->mode != S_IFGITLINK);
-		if (add_cacheinfo(opt, contents, path, 0, refresh,
-				  ADD_CACHE_OK_TO_ADD))
-			return -1;
-	}
-	return ret;
-}
-
-static int update_file(struct merge_options *opt,
-		       int clean,
-		       const struct diff_filespec *contents,
-		       const char *path)
-{
-	return update_file_flags(opt, contents, path,
-				 opt->priv->call_depth || clean, !opt->priv->call_depth);
-}
-
-/* Low level file merging, update and removal */
-
-struct merge_file_info {
-	struct diff_filespec blob; /* mostly use oid & mode; sometimes path */
-	unsigned clean:1,
-		 merge:1;
-};
-
-static int merge_3way(struct merge_options *opt,
-		      mmbuffer_t *result_buf,
-		      const struct diff_filespec *o,
-		      const struct diff_filespec *a,
-		      const struct diff_filespec *b,
-		      const char *branch1,
-		      const char *branch2,
-		      const int extra_marker_size)
-{
-	mmfile_t orig, src1, src2;
-	struct ll_merge_options ll_opts = LL_MERGE_OPTIONS_INIT;
-	char *base, *name1, *name2;
-	enum ll_merge_result merge_status;
-
-	ll_opts.renormalize = opt->renormalize;
-	ll_opts.extra_marker_size = extra_marker_size;
-	ll_opts.xdl_opts = opt->xdl_opts;
-	ll_opts.conflict_style = opt->conflict_style;
-
-	if (opt->priv->call_depth) {
-		ll_opts.virtual_ancestor = 1;
-		ll_opts.variant = 0;
-	} else {
-		switch (opt->recursive_variant) {
-		case MERGE_VARIANT_OURS:
-			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
-			break;
-		case MERGE_VARIANT_THEIRS:
-			ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
-			break;
-		default:
-			ll_opts.variant = 0;
-			break;
-		}
-	}
-
-	assert(a->path && b->path && o->path && opt->ancestor);
-	if (strcmp(a->path, b->path) || strcmp(a->path, o->path) != 0) {
-		base  = mkpathdup("%s:%s", opt->ancestor, o->path);
-		name1 = mkpathdup("%s:%s", branch1, a->path);
-		name2 = mkpathdup("%s:%s", branch2, b->path);
-	} else {
-		base  = mkpathdup("%s", opt->ancestor);
-		name1 = mkpathdup("%s", branch1);
-		name2 = mkpathdup("%s", branch2);
-	}
-
-	read_mmblob(&orig, &o->oid);
-	read_mmblob(&src1, &a->oid);
-	read_mmblob(&src2, &b->oid);
-
-	/*
-	 * FIXME: Using a->path for normalization rules in ll_merge could be
-	 * wrong if we renamed from a->path to b->path.  We should use the
-	 * target path for where the file will be written.
-	 */
-	merge_status = ll_merge(result_buf, a->path, &orig, base,
-				&src1, name1, &src2, name2,
-				opt->repo->index, &ll_opts);
-	if (merge_status == LL_MERGE_BINARY_CONFLICT)
-		warning("Cannot merge binary files: %s (%s vs. %s)",
-			a->path, name1, name2);
-
-	free(base);
-	free(name1);
-	free(name2);
-	free(orig.ptr);
-	free(src1.ptr);
-	free(src2.ptr);
-	return merge_status;
-}
-
-static int find_first_merges(struct repository *repo,
-			     struct object_array *result, const char *path,
-			     struct commit *a, struct commit *b)
-{
-	int i, j;
-	struct object_array merges = OBJECT_ARRAY_INIT;
-	struct commit *commit;
-	int contains_another;
-
-	char merged_revision[GIT_MAX_HEXSZ + 2];
-	const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
-				   "--all", merged_revision, NULL };
-	struct rev_info revs;
-	struct setup_revision_opt rev_opts;
-
-	memset(result, 0, sizeof(struct object_array));
-	memset(&rev_opts, 0, sizeof(rev_opts));
-
-	/* get all revisions that merge commit a */
-	xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
-		  oid_to_hex(&a->object.oid));
-	repo_init_revisions(repo, &revs, NULL);
-	/* FIXME: can't handle linked worktrees in submodules yet */
-	revs.single_worktree = path != NULL;
-	setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
-
-	/* save all revisions from the above list that contain b */
-	if (prepare_revision_walk(&revs))
-		die("revision walk setup failed");
-	while ((commit = get_revision(&revs)) != NULL) {
-		struct object *o = &(commit->object);
-		int ret = repo_in_merge_bases(repo, b, commit);
-		if (ret < 0) {
-			object_array_clear(&merges);
-			release_revisions(&revs);
-			return ret;
-		}
-		if (ret)
-			add_object_array(o, NULL, &merges);
-	}
-	reset_revision_walk();
-
-	/* Now we've got all merges that contain a and b. Prune all
-	 * merges that contain another found merge and save them in
-	 * result.
-	 */
-	for (i = 0; i < merges.nr; i++) {
-		struct commit *m1 = (struct commit *) merges.objects[i].item;
-
-		contains_another = 0;
-		for (j = 0; j < merges.nr; j++) {
-			struct commit *m2 = (struct commit *) merges.objects[j].item;
-			if (i != j) {
-				int ret = repo_in_merge_bases(repo, m2, m1);
-				if (ret < 0) {
-					object_array_clear(&merges);
-					release_revisions(&revs);
-					return ret;
-				}
-				if (ret > 0) {
-					contains_another = 1;
-					break;
-				}
-			}
-		}
-
-		if (!contains_another)
-			add_object_array(merges.objects[i].item, NULL, result);
-	}
-
-	object_array_clear(&merges);
-	release_revisions(&revs);
-	return result->nr;
-}
-
-static void print_commit(struct repository *repo, struct commit *commit)
-{
-	struct strbuf sb = STRBUF_INIT;
-	struct pretty_print_context ctx = {0};
-	ctx.date_mode.type = DATE_NORMAL;
-	/* FIXME: Merge this with output_commit_title() */
-	assert(!merge_remote_util(commit));
-	repo_format_commit_message(repo, commit, " %h: %m %s", &sb, &ctx);
-	fprintf(stderr, "%s\n", sb.buf);
-	strbuf_release(&sb);
-}
-
-static int is_valid(const struct diff_filespec *dfs)
-{
-	return dfs->mode != 0 && !is_null_oid(&dfs->oid);
-}
-
-static int merge_submodule(struct merge_options *opt,
-			   struct object_id *result, const char *path,
-			   const struct object_id *base, const struct object_id *a,
-			   const struct object_id *b)
-{
-	struct repository subrepo;
-	int ret = 0, ret2;
-	struct commit *commit_base, *commit_a, *commit_b;
-	int parent_count;
-	struct object_array merges;
-
-	int i;
-	int search = !opt->priv->call_depth;
-
-	/* store a in result in case we fail */
-	/* FIXME: This is the WRONG resolution for the recursive case when
-	 * we need to be careful to avoid accidentally matching either side.
-	 * Should probably use o instead there, much like we do for merging
-	 * binaries.
-	 */
-	oidcpy(result, a);
-
-	/* we can not handle deletion conflicts */
-	if (is_null_oid(base))
-		return 0;
-	if (is_null_oid(a))
-		return 0;
-	if (is_null_oid(b))
-		return 0;
-
-	if (repo_submodule_init(&subrepo, opt->repo, path, null_oid())) {
-		output(opt, 1, _("Failed to merge submodule %s (not checked out)"), path);
-		return 0;
-	}
-
-	if (!(commit_base = lookup_commit_reference(&subrepo, base)) ||
-	    !(commit_a = lookup_commit_reference(&subrepo, a)) ||
-	    !(commit_b = lookup_commit_reference(&subrepo, b))) {
-		output(opt, 1, _("Failed to merge submodule %s (commits not present)"), path);
-		goto cleanup;
-	}
-
-	/* check whether both changes are forward */
-	ret2 = repo_in_merge_bases(&subrepo, commit_base, commit_a);
-	if (ret2 < 0) {
-		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
-		ret = -1;
-		goto cleanup;
-	}
-	if (ret2 > 0)
-		ret2 = repo_in_merge_bases(&subrepo, commit_base, commit_b);
-	if (ret2 < 0) {
-		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
-		ret = -1;
-		goto cleanup;
-	}
-	if (!ret2) {
-		output(opt, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
-		goto cleanup;
-	}
-
-	/* Case #1: a is contained in b or vice versa */
-	ret2 = repo_in_merge_bases(&subrepo, commit_a, commit_b);
-	if (ret2 < 0) {
-		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
-		ret = -1;
-		goto cleanup;
-	}
-	if (ret2) {
-		oidcpy(result, b);
-		if (show(opt, 3)) {
-			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			repo_output_commit_title(opt, &subrepo, commit_b);
-		} else if (show(opt, 2))
-			output(opt, 2, _("Fast-forwarding submodule %s"), path);
-		else
-			; /* no output */
-
-		ret = 1;
-		goto cleanup;
-	}
-	ret2 = repo_in_merge_bases(&subrepo, commit_b, commit_a);
-	if (ret2 < 0) {
-		output(opt, 1, _("Failed to merge submodule %s (repository corrupt)"), path);
-		ret = -1;
-		goto cleanup;
-	}
-	if (ret2) {
-		oidcpy(result, a);
-		if (show(opt, 3)) {
-			output(opt, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
-			repo_output_commit_title(opt, &subrepo, commit_a);
-		} else if (show(opt, 2))
-			output(opt, 2, _("Fast-forwarding submodule %s"), path);
-		else
-			; /* no output */
-
-		ret = 1;
-		goto cleanup;
-	}
-
-	/*
-	 * Case #2: There are one or more merges that contain a and b in
-	 * the submodule. If there is only one, then present it as a
-	 * suggestion to the user, but leave it marked unmerged so the
-	 * user needs to confirm the resolution.
-	 */
-
-	/* Skip the search if makes no sense to the calling context.  */
-	if (!search)
-		goto cleanup;
-
-	/* find commit which merges them */
-	parent_count = find_first_merges(&subrepo, &merges, path,
-					 commit_a, commit_b);
-	switch (parent_count) {
-	case -1:
-		output(opt, 1,_("Failed to merge submodule %s (repository corrupt)"), path);
-		ret = -1;
-		break;
-	case 0:
-		output(opt, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
-		break;
-
-	case 1:
-		output(opt, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
-		output(opt, 2, _("Found a possible merge resolution for the submodule:\n"));
-		print_commit(&subrepo, (struct commit *) merges.objects[0].item);
-		output(opt, 2, _(
-		       "If this is correct simply add it to the index "
-		       "for example\n"
-		       "by using:\n\n"
-		       "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
-		       "which will accept this suggestion.\n"),
-		       oid_to_hex(&merges.objects[0].item->oid), path);
-		break;
-
-	default:
-		output(opt, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
-		for (i = 0; i < merges.nr; i++)
-			print_commit(&subrepo, (struct commit *) merges.objects[i].item);
-	}
-
-	object_array_clear(&merges);
-cleanup:
-	repo_clear(&subrepo);
-	return ret;
-}
-
-static int merge_mode_and_contents(struct merge_options *opt,
-				   const struct diff_filespec *o,
-				   const struct diff_filespec *a,
-				   const struct diff_filespec *b,
-				   const char *filename,
-				   const char *branch1,
-				   const char *branch2,
-				   const int extra_marker_size,
-				   struct merge_file_info *result)
-{
-	if (opt->branch1 != branch1) {
-		/*
-		 * It's weird getting a reverse merge with HEAD on the bottom
-		 * side of the conflict markers and the other branch on the
-		 * top.  Fix that.
-		 */
-		return merge_mode_and_contents(opt, o, b, a,
-					       filename,
-					       branch2, branch1,
-					       extra_marker_size, result);
-	}
-
-	result->merge = 0;
-	result->clean = 1;
-
-	if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
-		result->clean = 0;
-		/*
-		 * FIXME: This is a bad resolution for recursive case; for
-		 * the recursive case we want something that is unlikely to
-		 * accidentally match either side.  Also, while it makes
-		 * sense to prefer regular files over symlinks, it doesn't
-		 * make sense to prefer regular files over submodules.
-		 */
-		if (S_ISREG(a->mode)) {
-			result->blob.mode = a->mode;
-			oidcpy(&result->blob.oid, &a->oid);
-		} else {
-			result->blob.mode = b->mode;
-			oidcpy(&result->blob.oid, &b->oid);
-		}
-	} else {
-		if (!oideq(&a->oid, &o->oid) && !oideq(&b->oid, &o->oid))
-			result->merge = 1;
-
-		/*
-		 * Merge modes
-		 */
-		if (a->mode == b->mode || a->mode == o->mode)
-			result->blob.mode = b->mode;
-		else {
-			result->blob.mode = a->mode;
-			if (b->mode != o->mode) {
-				result->clean = 0;
-				result->merge = 1;
-			}
-		}
-
-		if (oideq(&a->oid, &b->oid) || oideq(&a->oid, &o->oid))
-			oidcpy(&result->blob.oid, &b->oid);
-		else if (oideq(&b->oid, &o->oid))
-			oidcpy(&result->blob.oid, &a->oid);
-		else if (S_ISREG(a->mode)) {
-			mmbuffer_t result_buf;
-			int ret = 0, merge_status;
-
-			merge_status = merge_3way(opt, &result_buf, o, a, b,
-						  branch1, branch2,
-						  extra_marker_size);
-
-			if ((merge_status < 0) || !result_buf.ptr)
-				ret = err(opt, _("failed to execute internal merge"));
-
-			if (!ret &&
-			    write_object_file(result_buf.ptr, result_buf.size,
-					      OBJ_BLOB, &result->blob.oid))
-				ret = err(opt, _("unable to add %s to database"),
-					  a->path);
-
-			free(result_buf.ptr);
-			if (ret)
-				return ret;
-			/* FIXME: bug, what if modes didn't match? */
-			result->clean = (merge_status == 0);
-		} else if (S_ISGITLINK(a->mode)) {
-			int clean = merge_submodule(opt, &result->blob.oid,
-						    o->path,
-						    &o->oid,
-						    &a->oid,
-						    &b->oid);
-			if (clean < 0)
-				return -1;
-			result->clean = clean;
-		} else if (S_ISLNK(a->mode)) {
-			switch (opt->recursive_variant) {
-			case MERGE_VARIANT_NORMAL:
-				oidcpy(&result->blob.oid, &a->oid);
-				if (!oideq(&a->oid, &b->oid))
-					result->clean = 0;
-				break;
-			case MERGE_VARIANT_OURS:
-				oidcpy(&result->blob.oid, &a->oid);
-				break;
-			case MERGE_VARIANT_THEIRS:
-				oidcpy(&result->blob.oid, &b->oid);
-				break;
-			}
-		} else
-			BUG("unsupported object type in the tree");
-	}
-
-	if (result->merge)
-		output(opt, 2, _("Auto-merging %s"), filename);
-
-	return 0;
-}
-
-static int handle_rename_via_dir(struct merge_options *opt,
-				 struct rename_conflict_info *ci)
-{
-	/*
-	 * Handle file adds that need to be renamed due to directory rename
-	 * detection.  This differs from handle_rename_normal, because
-	 * there is no content merge to do; just move the file into the
-	 * desired final location.
-	 */
-	const struct rename *ren = ci->ren1;
-	const struct diff_filespec *dest = ren->pair->two;
-	char *file_path = dest->path;
-	int mark_conflicted = (opt->detect_directory_renames ==
-			       MERGE_DIRECTORY_RENAMES_CONFLICT);
-	assert(ren->dir_rename_original_dest);
-
-	if (!opt->priv->call_depth && would_lose_untracked(opt, dest->path)) {
-		mark_conflicted = 1;
-		file_path = unique_path(opt, dest->path, ren->branch);
-		output(opt, 1, _("Error: Refusing to lose untracked file at %s; "
-				 "writing to %s instead."),
-		       dest->path, file_path);
-	}
-
-	if (mark_conflicted) {
-		/*
-		 * Write the file in worktree at file_path.  In the index,
-		 * only record the file at dest->path in the appropriate
-		 * higher stage.
-		 */
-		if (update_file(opt, 0, dest, file_path))
-			return -1;
-		if (file_path != dest->path)
-			free(file_path);
-		if (update_stages(opt, dest->path, NULL,
-				  ren->branch == opt->branch1 ? dest : NULL,
-				  ren->branch == opt->branch1 ? NULL : dest))
-			return -1;
-		return 0; /* not clean, but conflicted */
-	} else {
-		/* Update dest->path both in index and in worktree */
-		if (update_file(opt, 1, dest, dest->path))
-			return -1;
-		return 1; /* clean */
-	}
-}
-
-static int handle_change_delete(struct merge_options *opt,
-				const char *path, const char *old_path,
-				const struct diff_filespec *o,
-				const struct diff_filespec *changed,
-				const char *change_branch,
-				const char *delete_branch,
-				const char *change, const char *change_past)
-{
-	char *alt_path = NULL;
-	const char *update_path = path;
-	int ret = 0;
-
-	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0) ||
-	    (!opt->priv->call_depth && would_lose_untracked(opt, path))) {
-		update_path = alt_path = unique_path(opt, path, change_branch);
-	}
-
-	if (opt->priv->call_depth) {
-		/*
-		 * We cannot arbitrarily accept either a_sha or b_sha as
-		 * correct; since there is no true "middle point" between
-		 * them, simply reuse the base version for virtual merge base.
-		 */
-		ret = remove_file_from_index(opt->repo->index, path);
-		if (!ret)
-			ret = update_file(opt, 0, o, update_path);
-	} else {
-		/*
-		 * Despite the four nearly duplicate messages and argument
-		 * lists below and the ugliness of the nested if-statements,
-		 * having complete messages makes the job easier for
-		 * translators.
-		 *
-		 * The slight variance among the cases is due to the fact
-		 * that:
-		 *   1) directory/file conflicts (in effect if
-		 *      !alt_path) could cause us to need to write the
-		 *      file to a different path.
-		 *   2) renames (in effect if !old_path) could mean that
-		 *      there are two names for the path that the user
-		 *      may know the file by.
-		 */
-		if (!alt_path) {
-			if (!old_path) {
-				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
-				       "and %s in %s. Version %s of %s left in tree."),
-				       change, path, delete_branch, change_past,
-				       change_branch, change_branch, path);
-			} else {
-				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
-				       "and %s to %s in %s. Version %s of %s left in tree."),
-				       change, old_path, delete_branch, change_past, path,
-				       change_branch, change_branch, path);
-			}
-		} else {
-			if (!old_path) {
-				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
-				       "and %s in %s. Version %s of %s left in tree at %s."),
-				       change, path, delete_branch, change_past,
-				       change_branch, change_branch, path, alt_path);
-			} else {
-				output(opt, 1, _("CONFLICT (%s/delete): %s deleted in %s "
-				       "and %s to %s in %s. Version %s of %s left in tree at %s."),
-				       change, old_path, delete_branch, change_past, path,
-				       change_branch, change_branch, path, alt_path);
-			}
-		}
-		/*
-		 * No need to call update_file() on path when change_branch ==
-		 * opt->branch1 && !alt_path, since that would needlessly touch
-		 * path.  We could call update_file_flags() with update_cache=0
-		 * and update_wd=0, but that's a no-op.
-		 */
-		if (change_branch != opt->branch1 || alt_path)
-			ret = update_file(opt, 0, changed, update_path);
-	}
-	free(alt_path);
-
-	return ret;
-}
-
-static int handle_rename_delete(struct merge_options *opt,
-				struct rename_conflict_info *ci)
-{
-	const struct rename *ren = ci->ren1;
-	const struct diff_filespec *orig = ren->pair->one;
-	const struct diff_filespec *dest = ren->pair->two;
-	const char *rename_branch = ren->branch;
-	const char *delete_branch = (opt->branch1 == ren->branch ?
-				     opt->branch2 : opt->branch1);
-
-	if (handle_change_delete(opt,
-				 opt->priv->call_depth ? orig->path : dest->path,
-				 opt->priv->call_depth ? NULL : orig->path,
-				 orig, dest,
-				 rename_branch, delete_branch,
-				 _("rename"), _("renamed")))
-		return -1;
-
-	if (opt->priv->call_depth)
-		return remove_file_from_index(opt->repo->index, dest->path);
-	else
-		return update_stages(opt, dest->path, NULL,
-				     rename_branch == opt->branch1 ? dest : NULL,
-				     rename_branch == opt->branch1 ? NULL : dest);
-}
-
-static int handle_file_collision(struct merge_options *opt,
-				 const char *collide_path,
-				 const char *prev_path1,
-				 const char *prev_path2,
-				 const char *branch1, const char *branch2,
-				 struct diff_filespec *a,
-				 struct diff_filespec *b)
-{
-	struct merge_file_info mfi;
-	struct diff_filespec null;
-	char *alt_path = NULL;
-	const char *update_path = collide_path;
-
-	/*
-	 * It's easiest to get the correct things into stage 2 and 3, and
-	 * to make sure that the content merge puts HEAD before the other
-	 * branch if we just ensure that branch1 == opt->branch1.  So, simply
-	 * flip arguments around if we don't have that.
-	 */
-	if (branch1 != opt->branch1) {
-		return handle_file_collision(opt, collide_path,
-					     prev_path2, prev_path1,
-					     branch2, branch1,
-					     b, a);
-	}
-
-	/* Remove rename sources if rename/add or rename/rename(2to1) */
-	if (prev_path1)
-		remove_file(opt, 1, prev_path1,
-			    opt->priv->call_depth || would_lose_untracked(opt, prev_path1));
-	if (prev_path2)
-		remove_file(opt, 1, prev_path2,
-			    opt->priv->call_depth || would_lose_untracked(opt, prev_path2));
-
-	/*
-	 * Remove the collision path, if it wouldn't cause dirty contents
-	 * or an untracked file to get lost.  We'll either overwrite with
-	 * merged contents, or just write out to differently named files.
-	 */
-	if (was_dirty(opt, collide_path)) {
-		output(opt, 1, _("Refusing to lose dirty file at %s"),
-		       collide_path);
-		update_path = alt_path = unique_path(opt, collide_path, "merged");
-	} else if (would_lose_untracked(opt, collide_path)) {
-		/*
-		 * Only way we get here is if both renames were from
-		 * a directory rename AND user had an untracked file
-		 * at the location where both files end up after the
-		 * two directory renames.  See testcase 10d of t6043.
-		 */
-		output(opt, 1, _("Refusing to lose untracked file at "
-			       "%s, even though it's in the way."),
-		       collide_path);
-		update_path = alt_path = unique_path(opt, collide_path, "merged");
-	} else {
-		/*
-		 * FIXME: It's possible that the two files are identical
-		 * and that the current working copy happens to match, in
-		 * which case we are unnecessarily touching the working
-		 * tree file.  It's not a likely enough scenario that I
-		 * want to code up the checks for it and a better fix is
-		 * available if we restructure how unpack_trees() and
-		 * merge-recursive interoperate anyway, so punting for
-		 * now...
-		 */
-		remove_file(opt, 0, collide_path, 0);
-	}
-
-	/* Store things in diff_filespecs for functions that need it */
-	null.path = (char *)collide_path;
-	oidcpy(&null.oid, null_oid());
-	null.mode = 0;
-
-	if (merge_mode_and_contents(opt, &null, a, b, collide_path,
-				    branch1, branch2, opt->priv->call_depth * 2, &mfi))
-		return -1;
-	mfi.clean &= !alt_path;
-	if (update_file(opt, mfi.clean, &mfi.blob, update_path))
-		return -1;
-	if (!mfi.clean && !opt->priv->call_depth &&
-	    update_stages(opt, collide_path, NULL, a, b))
-		return -1;
-	free(alt_path);
-	/*
-	 * FIXME: If both a & b both started with conflicts (only possible
-	 * if they came from a rename/rename(2to1)), but had IDENTICAL
-	 * contents including those conflicts, then in the next line we claim
-	 * it was clean.  If someone cares about this case, we should have the
-	 * caller notify us if we started with conflicts.
-	 */
-	return mfi.clean;
-}
-
-static int handle_rename_add(struct merge_options *opt,
-			     struct rename_conflict_info *ci)
-{
-	/* a was renamed to c, and a separate c was added. */
-	struct diff_filespec *a = ci->ren1->pair->one;
-	struct diff_filespec *c = ci->ren1->pair->two;
-	char *path = c->path;
-	char *prev_path_desc;
-	struct merge_file_info mfi;
-
-	const char *rename_branch = ci->ren1->branch;
-	const char *add_branch = (opt->branch1 == rename_branch ?
-				  opt->branch2 : opt->branch1);
-	int other_stage = (ci->ren1->branch == opt->branch1 ? 3 : 2);
-
-	output(opt, 1, _("CONFLICT (rename/add): "
-	       "Rename %s->%s in %s.  Added %s in %s"),
-	       a->path, c->path, rename_branch,
-	       c->path, add_branch);
-
-	prev_path_desc = xstrfmt("version of %s from %s", path, a->path);
-	ci->ren1->src_entry->stages[other_stage].path = a->path;
-	if (merge_mode_and_contents(opt, a, c,
-				    &ci->ren1->src_entry->stages[other_stage],
-				    prev_path_desc,
-				    opt->branch1, opt->branch2,
-				    1 + opt->priv->call_depth * 2, &mfi))
-		return -1;
-	free(prev_path_desc);
-
-	ci->ren1->dst_entry->stages[other_stage].path = mfi.blob.path = c->path;
-	return handle_file_collision(opt,
-				     c->path, a->path, NULL,
-				     rename_branch, add_branch,
-				     &mfi.blob,
-				     &ci->ren1->dst_entry->stages[other_stage]);
-}
-
-static char *find_path_for_conflict(struct merge_options *opt,
-				    const char *path,
-				    const char *branch1,
-				    const char *branch2)
-{
-	char *new_path = NULL;
-	if (dir_in_way(opt->repo->index, path, !opt->priv->call_depth, 0)) {
-		new_path = unique_path(opt, path, branch1);
-		output(opt, 1, _("%s is a directory in %s adding "
-			       "as %s instead"),
-		       path, branch2, new_path);
-	} else if (would_lose_untracked(opt, path)) {
-		new_path = unique_path(opt, path, branch1);
-		output(opt, 1, _("Refusing to lose untracked file"
-			       " at %s; adding as %s instead"),
-		       path, new_path);
-	}
-
-	return new_path;
-}
-
-/*
- * Toggle the stage number between "ours" and "theirs" (2 and 3).
- */
-static inline int flip_stage(int stage)
-{
-	return (2 + 3) - stage;
-}
-
-static int handle_rename_rename_1to2(struct merge_options *opt,
-				     struct rename_conflict_info *ci)
-{
-	/* One file was renamed in both branches, but to different names. */
-	struct merge_file_info mfi;
-	struct diff_filespec *add;
-	struct diff_filespec *o = ci->ren1->pair->one;
-	struct diff_filespec *a = ci->ren1->pair->two;
-	struct diff_filespec *b = ci->ren2->pair->two;
-	char *path_desc;
-
-	output(opt, 1, _("CONFLICT (rename/rename): "
-	       "Rename \"%s\"->\"%s\" in branch \"%s\" "
-	       "rename \"%s\"->\"%s\" in \"%s\"%s"),
-	       o->path, a->path, ci->ren1->branch,
-	       o->path, b->path, ci->ren2->branch,
-	       opt->priv->call_depth ? _(" (left unresolved)") : "");
-
-	path_desc = xstrfmt("%s and %s, both renamed from %s",
-			    a->path, b->path, o->path);
-	if (merge_mode_and_contents(opt, o, a, b, path_desc,
-				    ci->ren1->branch, ci->ren2->branch,
-				    opt->priv->call_depth * 2, &mfi))
-		return -1;
-	free(path_desc);
-
-	if (opt->priv->call_depth)
-		remove_file_from_index(opt->repo->index, o->path);
-
-	/*
-	 * For each destination path, we need to see if there is a
-	 * rename/add collision.  If not, we can write the file out
-	 * to the specified location.
-	 */
-	add = &ci->ren1->dst_entry->stages[flip_stage(2)];
-	if (is_valid(add)) {
-		add->path = mfi.blob.path = a->path;
-		if (handle_file_collision(opt, a->path,
-					  NULL, NULL,
-					  ci->ren1->branch,
-					  ci->ren2->branch,
-					  &mfi.blob, add) < 0)
-			return -1;
-	} else {
-		char *new_path = find_path_for_conflict(opt, a->path,
-							ci->ren1->branch,
-							ci->ren2->branch);
-		if (update_file(opt, 0, &mfi.blob,
-				new_path ? new_path : a->path))
-			return -1;
-		free(new_path);
-		if (!opt->priv->call_depth &&
-		    update_stages(opt, a->path, NULL, a, NULL))
-			return -1;
-	}
-
-	if (!mfi.clean && mfi.blob.mode == a->mode &&
-	    oideq(&mfi.blob.oid, &a->oid)) {
-		/*
-		 * Getting here means we were attempting to merge a binary
-		 * blob.  Since we can't merge binaries, the merge algorithm
-		 * just takes one side.  But we don't want to copy the
-		 * contents of one side to both paths; we'd rather use the
-		 * original content at the given path for each path.
-		 */
-		oidcpy(&mfi.blob.oid, &b->oid);
-		mfi.blob.mode = b->mode;
-	}
-	add = &ci->ren2->dst_entry->stages[flip_stage(3)];
-	if (is_valid(add)) {
-		add->path = mfi.blob.path = b->path;
-		if (handle_file_collision(opt, b->path,
-					  NULL, NULL,
-					  ci->ren1->branch,
-					  ci->ren2->branch,
-					  add, &mfi.blob) < 0)
-			return -1;
-	} else {
-		char *new_path = find_path_for_conflict(opt, b->path,
-							ci->ren2->branch,
-							ci->ren1->branch);
-		if (update_file(opt, 0, &mfi.blob,
-				new_path ? new_path : b->path))
-			return -1;
-		free(new_path);
-		if (!opt->priv->call_depth &&
-		    update_stages(opt, b->path, NULL, NULL, b))
-			return -1;
-	}
-
-	return 0;
-}
-
-static int handle_rename_rename_2to1(struct merge_options *opt,
-				     struct rename_conflict_info *ci)
-{
-	/* Two files, a & b, were renamed to the same thing, c. */
-	struct diff_filespec *a = ci->ren1->pair->one;
-	struct diff_filespec *b = ci->ren2->pair->one;
-	struct diff_filespec *c1 = ci->ren1->pair->two;
-	struct diff_filespec *c2 = ci->ren2->pair->two;
-	char *path = c1->path; /* == c2->path */
-	char *path_side_1_desc;
-	char *path_side_2_desc;
-	struct merge_file_info mfi_c1;
-	struct merge_file_info mfi_c2;
-	int ostage1, ostage2;
-
-	output(opt, 1, _("CONFLICT (rename/rename): "
-	       "Rename %s->%s in %s. "
-	       "Rename %s->%s in %s"),
-	       a->path, c1->path, ci->ren1->branch,
-	       b->path, c2->path, ci->ren2->branch);
-
-	path_side_1_desc = xstrfmt("version of %s from %s", path, a->path);
-	path_side_2_desc = xstrfmt("version of %s from %s", path, b->path);
-	ostage1 = ci->ren1->branch == opt->branch1 ? 3 : 2;
-	ostage2 = flip_stage(ostage1);
-	ci->ren1->src_entry->stages[ostage1].path = a->path;
-	ci->ren2->src_entry->stages[ostage2].path = b->path;
-	if (merge_mode_and_contents(opt, a, c1,
-				    &ci->ren1->src_entry->stages[ostage1],
-				    path_side_1_desc,
-				    opt->branch1, opt->branch2,
-				    1 + opt->priv->call_depth * 2, &mfi_c1) ||
-	    merge_mode_and_contents(opt, b,
-				    &ci->ren2->src_entry->stages[ostage2],
-				    c2, path_side_2_desc,
-				    opt->branch1, opt->branch2,
-				    1 + opt->priv->call_depth * 2, &mfi_c2))
-		return -1;
-	free(path_side_1_desc);
-	free(path_side_2_desc);
-	mfi_c1.blob.path = path;
-	mfi_c2.blob.path = path;
-
-	return handle_file_collision(opt, path, a->path, b->path,
-				     ci->ren1->branch, ci->ren2->branch,
-				     &mfi_c1.blob, &mfi_c2.blob);
-}
-
-/*
- * Get the diff_filepairs changed between o_tree and tree.
- */
-static struct diff_queue_struct *get_diffpairs(struct merge_options *opt,
-					       struct tree *o_tree,
-					       struct tree *tree)
-{
-	struct diff_queue_struct *ret;
-	struct diff_options opts;
-
-	repo_diff_setup(opt->repo, &opts);
-	opts.flags.recursive = 1;
-	opts.flags.rename_empty = 0;
-	opts.detect_rename = merge_detect_rename(opt);
-	/*
-	 * We do not have logic to handle the detection of copies.  In
-	 * fact, it may not even make sense to add such logic: would we
-	 * really want a change to a base file to be propagated through
-	 * multiple other files by a merge?
-	 */
-	if (opts.detect_rename > DIFF_DETECT_RENAME)
-		opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = (opt->rename_limit >= 0) ? opt->rename_limit : 7000;
-	opts.rename_score = opt->rename_score;
-	opts.show_rename_progress = opt->show_rename_progress;
-	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	diff_setup_done(&opts);
-	diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
-	diffcore_std(&opts);
-	if (opts.needed_rename_limit > opt->priv->needed_rename_limit)
-		opt->priv->needed_rename_limit = opts.needed_rename_limit;
-
-	ret = xmalloc(sizeof(*ret));
-	*ret = diff_queued_diff;
-
-	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
-	diff_queued_diff.nr = 0;
-	diff_queued_diff.queue = NULL;
-	diff_flush(&opts);
-	return ret;
-}
-
-static int tree_has_path(struct repository *r, struct tree *tree,
-			 const char *path)
-{
-	struct object_id hashy;
-	unsigned short mode_o;
-
-	return !get_tree_entry(r,
-			       &tree->object.oid, path,
-			       &hashy, &mode_o);
-}
-
-/*
- * Return a new string that replaces the beginning portion (which matches
- * entry->dir), with entry->new_dir.  In perl-speak:
- *   new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
- * NOTE:
- *   Caller must ensure that old_path starts with entry->dir + '/'.
- */
-static char *apply_dir_rename(struct dir_rename_entry *entry,
-			      const char *old_path)
-{
-	struct strbuf new_path = STRBUF_INIT;
-	int oldlen, newlen;
-
-	if (entry->non_unique_new_dir)
-		return NULL;
-
-	oldlen = strlen(entry->dir);
-	if (entry->new_dir.len == 0)
-		/*
-		 * If someone renamed/merged a subdirectory into the root
-		 * directory (e.g. 'some/subdir' -> ''), then we want to
-		 * avoid returning
-		 *     '' + '/filename'
-		 * as the rename; we need to make old_path + oldlen advance
-		 * past the '/' character.
-		 */
-		oldlen++;
-	newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
-	strbuf_grow(&new_path, newlen);
-	strbuf_addbuf(&new_path, &entry->new_dir);
-	strbuf_addstr(&new_path, &old_path[oldlen]);
-
-	return strbuf_detach(&new_path, NULL);
-}
-
-static void get_renamed_dir_portion(const char *old_path, const char *new_path,
-				    char **old_dir, char **new_dir)
-{
-	char *end_of_old, *end_of_new;
-
-	/* Default return values: NULL, meaning no rename */
-	*old_dir = NULL;
-	*new_dir = NULL;
-
-	/*
-	 * For
-	 *    "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
-	 * the "e/foo.c" part is the same, we just want to know that
-	 *    "a/b/c/d" was renamed to "a/b/some/thing/else"
-	 * so, for this example, this function returns "a/b/c/d" in
-	 * *old_dir and "a/b/some/thing/else" in *new_dir.
-	 */
-
-	/*
-	 * If the basename of the file changed, we don't care.  We want
-	 * to know which portion of the directory, if any, changed.
-	 */
-	end_of_old = strrchr(old_path, '/');
-	end_of_new = strrchr(new_path, '/');
-
-	/*
-	 * If end_of_old is NULL, old_path wasn't in a directory, so there
-	 * could not be a directory rename (our rule elsewhere that a
-	 * directory which still exists is not considered to have been
-	 * renamed means the root directory can never be renamed -- because
-	 * the root directory always exists).
-	 */
-	if (!end_of_old)
-		return; /* Note: *old_dir and *new_dir are still NULL */
-
-	/*
-	 * If new_path contains no directory (end_of_new is NULL), then we
-	 * have a rename of old_path's directory to the root directory.
-	 */
-	if (!end_of_new) {
-		*old_dir = xstrndup(old_path, end_of_old - old_path);
-		*new_dir = xstrdup("");
-		return;
-	}
-
-	/* Find the first non-matching character traversing backwards */
-	while (*--end_of_new == *--end_of_old &&
-	       end_of_old != old_path &&
-	       end_of_new != new_path)
-		; /* Do nothing; all in the while loop */
-
-	/*
-	 * If both got back to the beginning of their strings, then the
-	 * directory didn't change at all, only the basename did.
-	 */
-	if (end_of_old == old_path && end_of_new == new_path &&
-	    *end_of_old == *end_of_new)
-		return; /* Note: *old_dir and *new_dir are still NULL */
-
-	/*
-	 * If end_of_new got back to the beginning of its string, and
-	 * end_of_old got back to the beginning of some subdirectory, then
-	 * we have a rename/merge of a subdirectory into the root, which
-	 * needs slightly special handling.
-	 *
-	 * Note: There is no need to consider the opposite case, with a
-	 * rename/merge of the root directory into some subdirectory
-	 * because as noted above the root directory always exists so it
-	 * cannot be considered to be renamed.
-	 */
-	if (end_of_new == new_path &&
-	    end_of_old != old_path && end_of_old[-1] == '/') {
-		*old_dir = xstrndup(old_path, --end_of_old - old_path);
-		*new_dir = xstrdup("");
-		return;
-	}
-
-	/*
-	 * We've found the first non-matching character in the directory
-	 * paths.  That means the current characters we were looking at
-	 * were part of the first non-matching subdir name going back from
-	 * the end of the strings.  Get the whole name by advancing both
-	 * end_of_old and end_of_new to the NEXT '/' character.  That will
-	 * represent the entire directory rename.
-	 *
-	 * The reason for the increment is cases like
-	 *    a/b/star/foo/whatever.c -> a/b/tar/foo/random.c
-	 * After dropping the basename and going back to the first
-	 * non-matching character, we're now comparing:
-	 *    a/b/s          and         a/b/
-	 * and we want to be comparing:
-	 *    a/b/star/      and         a/b/tar/
-	 * but without the pre-increment, the one on the right would stay
-	 * a/b/.
-	 */
-	end_of_old = strchr(++end_of_old, '/');
-	end_of_new = strchr(++end_of_new, '/');
-
-	/* Copy the old and new directories into *old_dir and *new_dir. */
-	*old_dir = xstrndup(old_path, end_of_old - old_path);
-	*new_dir = xstrndup(new_path, end_of_new - new_path);
-}
-
-static void remove_hashmap_entries(struct hashmap *dir_renames,
-				   struct string_list *items_to_remove)
-{
-	int i;
-	struct dir_rename_entry *entry;
-
-	for (i = 0; i < items_to_remove->nr; i++) {
-		entry = items_to_remove->items[i].util;
-		hashmap_remove(dir_renames, &entry->ent, NULL);
-	}
-	string_list_clear(items_to_remove, 0);
-}
-
-/*
- * See if there is a directory rename for path, and if there are any file
- * level conflicts for the renamed location.  If there is a rename and
- * there are no conflicts, return the new name.  Otherwise, return NULL.
- */
-static char *handle_path_level_conflicts(struct merge_options *opt,
-					 const char *path,
-					 struct dir_rename_entry *entry,
-					 struct hashmap *collisions,
-					 struct tree *tree)
-{
-	char *new_path = NULL;
-	struct collision_entry *collision_ent;
-	int clean = 1;
-	struct strbuf collision_paths = STRBUF_INIT;
-
-	/*
-	 * entry has the mapping of old directory name to new directory name
-	 * that we want to apply to path.
-	 */
-	new_path = apply_dir_rename(entry, path);
-
-	if (!new_path) {
-		/* This should only happen when entry->non_unique_new_dir set */
-		if (!entry->non_unique_new_dir)
-			BUG("entry->non_unique_new_dir not set and !new_path");
-		output(opt, 1, _("CONFLICT (directory rename split): "
-			       "Unclear where to place %s because directory "
-			       "%s was renamed to multiple other directories, "
-			       "with no destination getting a majority of the "
-			       "files."),
-		       path, entry->dir);
-		clean = 0;
-		return NULL;
-	}
-
-	/*
-	 * The caller needs to have ensured that it has pre-populated
-	 * collisions with all paths that map to new_path.  Do a quick check
-	 * to ensure that's the case.
-	 */
-	collision_ent = collision_find_entry(collisions, new_path);
-	if (!collision_ent)
-		BUG("collision_ent is NULL");
-
-	/*
-	 * Check for one-sided add/add/.../add conflicts, i.e.
-	 * where implicit renames from the other side doing
-	 * directory rename(s) can affect this side of history
-	 * to put multiple paths into the same location.  Warn
-	 * and bail on directory renames for such paths.
-	 */
-	if (collision_ent->reported_already) {
-		clean = 0;
-	} else if (tree_has_path(opt->repo, tree, new_path)) {
-		collision_ent->reported_already = 1;
-		strbuf_add_separated_string_list(&collision_paths, ", ",
-						 &collision_ent->source_files);
-		output(opt, 1, _("CONFLICT (implicit dir rename): Existing "
-			       "file/dir at %s in the way of implicit "
-			       "directory rename(s) putting the following "
-			       "path(s) there: %s."),
-		       new_path, collision_paths.buf);
-		clean = 0;
-	} else if (collision_ent->source_files.nr > 1) {
-		collision_ent->reported_already = 1;
-		strbuf_add_separated_string_list(&collision_paths, ", ",
-						 &collision_ent->source_files);
-		output(opt, 1, _("CONFLICT (implicit dir rename): Cannot map "
-			       "more than one path to %s; implicit directory "
-			       "renames tried to put these paths there: %s"),
-		       new_path, collision_paths.buf);
-		clean = 0;
-	}
-
-	/* Free memory we no longer need */
-	strbuf_release(&collision_paths);
-	if (!clean && new_path) {
-		free(new_path);
-		return NULL;
-	}
-
-	return new_path;
-}
-
-/*
- * There are a couple things we want to do at the directory level:
- *   1. Check for both sides renaming to the same thing, in order to avoid
- *      implicit renaming of files that should be left in place.  (See
- *      testcase 6b in t6043 for details.)
- *   2. Prune directory renames if there are still files left in the
- *      original directory.  These represent a partial directory rename,
- *      i.e. a rename where only some of the files within the directory
- *      were renamed elsewhere.  (Technically, this could be done earlier
- *      in get_directory_renames(), except that would prevent us from
- *      doing the previous check and thus failing testcase 6b.)
- *   3. Check for rename/rename(1to2) conflicts (at the directory level).
- *      In the future, we could potentially record this info as well and
- *      omit reporting rename/rename(1to2) conflicts for each path within
- *      the affected directories, thus cleaning up the merge output.
- *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
- *         directory level, because merging directories is fine.  If it
- *         causes conflicts for files within those merged directories, then
- *         that should be detected at the individual path level.
- */
-static void handle_directory_level_conflicts(struct merge_options *opt,
-					     struct hashmap *dir_re_head,
-					     struct tree *head,
-					     struct hashmap *dir_re_merge,
-					     struct tree *merge)
-{
-	struct hashmap_iter iter;
-	struct dir_rename_entry *head_ent;
-	struct dir_rename_entry *merge_ent;
-
-	struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
-	struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
-
-	hashmap_for_each_entry(dir_re_head, &iter, head_ent,
-				ent /* member name */) {
-		merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
-		if (merge_ent &&
-		    !head_ent->non_unique_new_dir &&
-		    !merge_ent->non_unique_new_dir &&
-		    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
-			/* 1. Renamed identically; remove it from both sides */
-			string_list_append(&remove_from_head,
-					   head_ent->dir)->util = head_ent;
-			strbuf_release(&head_ent->new_dir);
-			string_list_append(&remove_from_merge,
-					   merge_ent->dir)->util = merge_ent;
-			strbuf_release(&merge_ent->new_dir);
-		} else if (tree_has_path(opt->repo, head, head_ent->dir)) {
-			/* 2. This wasn't a directory rename after all */
-			string_list_append(&remove_from_head,
-					   head_ent->dir)->util = head_ent;
-			strbuf_release(&head_ent->new_dir);
-		}
-	}
-
-	remove_hashmap_entries(dir_re_head, &remove_from_head);
-	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
-
-	hashmap_for_each_entry(dir_re_merge, &iter, merge_ent,
-				ent /* member name */) {
-		head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
-		if (tree_has_path(opt->repo, merge, merge_ent->dir)) {
-			/* 2. This wasn't a directory rename after all */
-			string_list_append(&remove_from_merge,
-					   merge_ent->dir)->util = merge_ent;
-		} else if (head_ent &&
-			   !head_ent->non_unique_new_dir &&
-			   !merge_ent->non_unique_new_dir) {
-			/* 3. rename/rename(1to2) */
-			/*
-			 * We can assume it's not rename/rename(1to1) because
-			 * that was case (1), already checked above.  So we
-			 * know that head_ent->new_dir and merge_ent->new_dir
-			 * are different strings.
-			 */
-			output(opt, 1, _("CONFLICT (rename/rename): "
-				       "Rename directory %s->%s in %s. "
-				       "Rename directory %s->%s in %s"),
-			       head_ent->dir, head_ent->new_dir.buf, opt->branch1,
-			       head_ent->dir, merge_ent->new_dir.buf, opt->branch2);
-			string_list_append(&remove_from_head,
-					   head_ent->dir)->util = head_ent;
-			strbuf_release(&head_ent->new_dir);
-			string_list_append(&remove_from_merge,
-					   merge_ent->dir)->util = merge_ent;
-			strbuf_release(&merge_ent->new_dir);
-		}
-	}
-
-	remove_hashmap_entries(dir_re_head, &remove_from_head);
-	remove_hashmap_entries(dir_re_merge, &remove_from_merge);
-}
-
-static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs)
-{
-	struct hashmap *dir_renames;
-	struct hashmap_iter iter;
-	struct dir_rename_entry *entry;
-	int i;
-
-	/*
-	 * Typically, we think of a directory rename as all files from a
-	 * certain directory being moved to a target directory.  However,
-	 * what if someone first moved two files from the original
-	 * directory in one commit, and then renamed the directory
-	 * somewhere else in a later commit?  At merge time, we just know
-	 * that files from the original directory went to two different
-	 * places, and that the bulk of them ended up in the same place.
-	 * We want each directory rename to represent where the bulk of the
-	 * files from that directory end up; this function exists to find
-	 * where the bulk of the files went.
-	 *
-	 * The first loop below simply iterates through the list of file
-	 * renames, finding out how often each directory rename pair
-	 * possibility occurs.
-	 */
-	dir_renames = xmalloc(sizeof(*dir_renames));
-	dir_rename_init(dir_renames);
-	for (i = 0; i < pairs->nr; ++i) {
-		struct string_list_item *item;
-		int *count;
-		struct diff_filepair *pair = pairs->queue[i];
-		char *old_dir, *new_dir;
-
-		/* File not part of directory rename if it wasn't renamed */
-		if (pair->status != 'R')
-			continue;
-
-		get_renamed_dir_portion(pair->one->path, pair->two->path,
-					&old_dir,        &new_dir);
-		if (!old_dir)
-			/* Directory didn't change at all; ignore this one. */
-			continue;
-
-		entry = dir_rename_find_entry(dir_renames, old_dir);
-		if (!entry) {
-			entry = xmalloc(sizeof(*entry));
-			dir_rename_entry_init(entry, old_dir);
-			hashmap_put(dir_renames, &entry->ent);
-		} else {
-			free(old_dir);
-		}
-		item = string_list_lookup(&entry->possible_new_dirs, new_dir);
-		if (!item) {
-			item = string_list_insert(&entry->possible_new_dirs,
-						  new_dir);
-			item->util = xcalloc(1, sizeof(int));
-		} else {
-			free(new_dir);
-		}
-		count = item->util;
-		*count += 1;
-	}
-
-	/*
-	 * For each directory with files moved out of it, we find out which
-	 * target directory received the most files so we can declare it to
-	 * be the "winning" target location for the directory rename.  This
-	 * winner gets recorded in new_dir.  If there is no winner
-	 * (multiple target directories received the same number of files),
-	 * we set non_unique_new_dir.  Once we've determined the winner (or
-	 * that there is no winner), we no longer need possible_new_dirs.
-	 */
-	hashmap_for_each_entry(dir_renames, &iter, entry,
-				ent /* member name */) {
-		int max = 0;
-		int bad_max = 0;
-		char *best = NULL;
-
-		for (i = 0; i < entry->possible_new_dirs.nr; i++) {
-			int *count = entry->possible_new_dirs.items[i].util;
-
-			if (*count == max)
-				bad_max = max;
-			else if (*count > max) {
-				max = *count;
-				best = entry->possible_new_dirs.items[i].string;
-			}
-		}
-		if (bad_max == max)
-			entry->non_unique_new_dir = 1;
-		else {
-			assert(entry->new_dir.len == 0);
-			strbuf_addstr(&entry->new_dir, best);
-		}
-		/*
-		 * The relevant directory sub-portion of the original full
-		 * filepaths were xstrndup'ed before inserting into
-		 * possible_new_dirs, and instead of manually iterating the
-		 * list and free'ing each, just lie and tell
-		 * possible_new_dirs that it did the strdup'ing so that it
-		 * will free them for us.
-		 */
-		entry->possible_new_dirs.strdup_strings = 1;
-		string_list_clear(&entry->possible_new_dirs, 1);
-	}
-
-	return dir_renames;
-}
-
-static struct dir_rename_entry *check_dir_renamed(const char *path,
-						  struct hashmap *dir_renames)
-{
-	char *temp = xstrdup(path);
-	char *end;
-	struct dir_rename_entry *entry = NULL;
-
-	while ((end = strrchr(temp, '/'))) {
-		*end = '\0';
-		entry = dir_rename_find_entry(dir_renames, temp);
-		if (entry)
-			break;
-	}
-	free(temp);
-	return entry;
-}
-
-static void compute_collisions(struct hashmap *collisions,
-			       struct hashmap *dir_renames,
-			       struct diff_queue_struct *pairs)
-{
-	int i;
-
-	/*
-	 * Multiple files can be mapped to the same path due to directory
-	 * renames done by the other side of history.  Since that other
-	 * side of history could have merged multiple directories into one,
-	 * if our side of history added the same file basename to each of
-	 * those directories, then all N of them would get implicitly
-	 * renamed by the directory rename detection into the same path,
-	 * and we'd get an add/add/.../add conflict, and all those adds
-	 * from *this* side of history.  This is not representable in the
-	 * index, and users aren't going to easily be able to make sense of
-	 * it.  So we need to provide a good warning about what's
-	 * happening, and fall back to no-directory-rename detection
-	 * behavior for those paths.
-	 *
-	 * See testcases 9e and all of section 5 from t6043 for examples.
-	 */
-	collision_init(collisions);
-
-	for (i = 0; i < pairs->nr; ++i) {
-		struct dir_rename_entry *dir_rename_ent;
-		struct collision_entry *collision_ent;
-		char *new_path;
-		struct diff_filepair *pair = pairs->queue[i];
-
-		if (pair->status != 'A' && pair->status != 'R')
-			continue;
-		dir_rename_ent = check_dir_renamed(pair->two->path,
-						   dir_renames);
-		if (!dir_rename_ent)
-			continue;
-
-		new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
-		if (!new_path)
-			/*
-			 * dir_rename_ent->non_unique_new_path is true, which
-			 * means there is no directory rename for us to use,
-			 * which means it won't cause us any additional
-			 * collisions.
-			 */
-			continue;
-		collision_ent = collision_find_entry(collisions, new_path);
-		if (!collision_ent) {
-			CALLOC_ARRAY(collision_ent, 1);
-			hashmap_entry_init(&collision_ent->ent,
-						strhash(new_path));
-			hashmap_put(collisions, &collision_ent->ent);
-			collision_ent->target_file = new_path;
-		} else {
-			free(new_path);
-		}
-		string_list_insert(&collision_ent->source_files,
-				   pair->two->path);
-	}
-}
-
-static char *check_for_directory_rename(struct merge_options *opt,
-					const char *path,
-					struct tree *tree,
-					struct hashmap *dir_renames,
-					struct hashmap *dir_rename_exclusions,
-					struct hashmap *collisions,
-					int *clean_merge)
-{
-	char *new_path = NULL;
-	struct dir_rename_entry *entry = check_dir_renamed(path, dir_renames);
-	struct dir_rename_entry *oentry = NULL;
-
-	if (!entry)
-		return new_path;
-
-	/*
-	 * This next part is a little weird.  We do not want to do an
-	 * implicit rename into a directory we renamed on our side, because
-	 * that will result in a spurious rename/rename(1to2) conflict.  An
-	 * example:
-	 *   Base commit: dumbdir/afile, otherdir/bfile
-	 *   Side 1:      smrtdir/afile, otherdir/bfile
-	 *   Side 2:      dumbdir/afile, dumbdir/bfile
-	 * Here, while working on Side 1, we could notice that otherdir was
-	 * renamed/merged to dumbdir, and change the diff_filepair for
-	 * otherdir/bfile into a rename into dumbdir/bfile.  However, Side
-	 * 2 will notice the rename from dumbdir to smrtdir, and do the
-	 * transitive rename to move it from dumbdir/bfile to
-	 * smrtdir/bfile.  That gives us bfile in dumbdir vs being in
-	 * smrtdir, a rename/rename(1to2) conflict.  We really just want
-	 * the file to end up in smrtdir.  And the way to achieve that is
-	 * to not let Side1 do the rename to dumbdir, since we know that is
-	 * the source of one of our directory renames.
-	 *
-	 * That's why oentry and dir_rename_exclusions is here.
-	 *
-	 * As it turns out, this also prevents N-way transient rename
-	 * confusion; See testcases 9c and 9d of t6043.
-	 */
-	oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
-	if (oentry) {
-		output(opt, 1, _("WARNING: Avoiding applying %s -> %s rename "
-			       "to %s, because %s itself was renamed."),
-		       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
-	} else {
-		new_path = handle_path_level_conflicts(opt, path, entry,
-						       collisions, tree);
-		*clean_merge &= (new_path != NULL);
-	}
-
-	return new_path;
-}
-
-static void apply_directory_rename_modifications(struct merge_options *opt,
-						 struct diff_filepair *pair,
-						 char *new_path,
-						 struct rename *re,
-						 struct tree *tree,
-						 struct tree *o_tree,
-						 struct tree *a_tree,
-						 struct tree *b_tree,
-						 struct string_list *entries)
-{
-	struct string_list_item *item;
-	int stage = (tree == a_tree ? 2 : 3);
-	int update_wd;
-
-	/*
-	 * In all cases where we can do directory rename detection,
-	 * unpack_trees() will have read pair->two->path into the
-	 * index and the working copy.  We need to remove it so that
-	 * we can instead place it at new_path.  It is guaranteed to
-	 * not be untracked (unpack_trees() would have errored out
-	 * saying the file would have been overwritten), but it might
-	 * be dirty, though.
-	 */
-	update_wd = !was_dirty(opt, pair->two->path);
-	if (!update_wd)
-		output(opt, 1, _("Refusing to lose dirty file at %s"),
-		       pair->two->path);
-	remove_file(opt, 1, pair->two->path, !update_wd);
-
-	/* Find or create a new re->dst_entry */
-	item = string_list_lookup(entries, new_path);
-	if (item) {
-		/*
-		 * Since we're renaming on this side of history, and it's
-		 * due to a directory rename on the other side of history
-		 * (which we only allow when the directory in question no
-		 * longer exists on the other side of history), the
-		 * original entry for re->dst_entry is no longer
-		 * necessary...
-		 */
-		re->dst_entry->processed = 1;
-
-		/*
-		 * ...because we'll be using this new one.
-		 */
-		re->dst_entry = item->util;
-	} else {
-		/*
-		 * re->dst_entry is for the before-dir-rename path, and we
-		 * need it to hold information for the after-dir-rename
-		 * path.  Before creating a new entry, we need to mark the
-		 * old one as unnecessary (...unless it is shared by
-		 * src_entry, i.e. this didn't use to be a rename, in which
-		 * case we can just allow the normal processing to happen
-		 * for it).
-		 */
-		if (pair->status == 'R')
-			re->dst_entry->processed = 1;
-
-		re->dst_entry = insert_stage_data(opt->repo, new_path,
-						  o_tree, a_tree, b_tree,
-						  entries);
-		item = string_list_insert(entries, new_path);
-		item->util = re->dst_entry;
-	}
-
-	/*
-	 * Update the stage_data with the information about the path we are
-	 * moving into place.  That slot will be empty and available for us
-	 * to write to because of the collision checks in
-	 * handle_path_level_conflicts().  In other words,
-	 * re->dst_entry->stages[stage].oid will be the null_oid, so it's
-	 * open for us to write to.
-	 *
-	 * It may be tempting to actually update the index at this point as
-	 * well, using update_stages_for_stage_data(), but as per the big
-	 * "NOTE" in update_stages(), doing so will modify the current
-	 * in-memory index which will break calls to would_lose_untracked()
-	 * that we need to make.  Instead, we need to just make sure that
-	 * the various handle_rename_*() functions update the index
-	 * explicitly rather than relying on unpack_trees() to have done it.
-	 */
-	get_tree_entry(opt->repo,
-		       &tree->object.oid,
-		       pair->two->path,
-		       &re->dst_entry->stages[stage].oid,
-		       &re->dst_entry->stages[stage].mode);
-
-	/*
-	 * Record the original change status (or 'type' of change).  If it
-	 * was originally an add ('A'), this lets us differentiate later
-	 * between a RENAME_DELETE conflict and RENAME_VIA_DIR (they
-	 * otherwise look the same).  If it was originally a rename ('R'),
-	 * this lets us remember and report accurately about the transitive
-	 * renaming that occurred via the directory rename detection.  Also,
-	 * record the original destination name.
-	 */
-	re->dir_rename_original_type = pair->status;
-	re->dir_rename_original_dest = pair->two->path;
-
-	/*
-	 * We don't actually look at pair->status again, but it seems
-	 * pedagogically correct to adjust it.
-	 */
-	pair->status = 'R';
-
-	/*
-	 * Finally, record the new location.
-	 */
-	pair->two->path = new_path;
-}
-
-/*
- * Get information of all renames which occurred in 'pairs', making use of
- * any implicit directory renames inferred from the other side of history.
- * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
- * to be able to associate the correct cache entries with the rename
- * information; tree is always equal to either a_tree or b_tree.
- */
-static struct string_list *get_renames(struct merge_options *opt,
-				       const char *branch,
-				       struct diff_queue_struct *pairs,
-				       struct hashmap *dir_renames,
-				       struct hashmap *dir_rename_exclusions,
-				       struct tree *tree,
-				       struct tree *o_tree,
-				       struct tree *a_tree,
-				       struct tree *b_tree,
-				       struct string_list *entries,
-				       int *clean_merge)
-{
-	int i;
-	struct hashmap collisions;
-	struct hashmap_iter iter;
-	struct collision_entry *e;
-	struct string_list *renames;
-
-	compute_collisions(&collisions, dir_renames, pairs);
-	CALLOC_ARRAY(renames, 1);
-
-	for (i = 0; i < pairs->nr; ++i) {
-		struct string_list_item *item;
-		struct rename *re;
-		struct diff_filepair *pair = pairs->queue[i];
-		char *new_path; /* non-NULL only with directory renames */
-
-		if (pair->status != 'A' && pair->status != 'R') {
-			diff_free_filepair(pair);
-			continue;
-		}
-		new_path = check_for_directory_rename(opt, pair->two->path, tree,
-						      dir_renames,
-						      dir_rename_exclusions,
-						      &collisions,
-						      clean_merge);
-		if (pair->status != 'R' && !new_path) {
-			diff_free_filepair(pair);
-			continue;
-		}
-
-		re = xmalloc(sizeof(*re));
-		re->processed = 0;
-		re->pair = pair;
-		re->branch = branch;
-		re->dir_rename_original_type = '\0';
-		re->dir_rename_original_dest = NULL;
-		item = string_list_lookup(entries, re->pair->one->path);
-		if (!item)
-			re->src_entry = insert_stage_data(opt->repo,
-					re->pair->one->path,
-					o_tree, a_tree, b_tree, entries);
-		else
-			re->src_entry = item->util;
-
-		item = string_list_lookup(entries, re->pair->two->path);
-		if (!item)
-			re->dst_entry = insert_stage_data(opt->repo,
-					re->pair->two->path,
-					o_tree, a_tree, b_tree, entries);
-		else
-			re->dst_entry = item->util;
-		item = string_list_insert(renames, pair->one->path);
-		item->util = re;
-		if (new_path)
-			apply_directory_rename_modifications(opt, pair, new_path,
-							     re, tree, o_tree,
-							     a_tree, b_tree,
-							     entries);
-	}
-
-	hashmap_for_each_entry(&collisions, &iter, e,
-				ent /* member name */) {
-		free(e->target_file);
-		string_list_clear(&e->source_files, 0);
-	}
-	hashmap_clear_and_free(&collisions, struct collision_entry, ent);
-	return renames;
-}
-
-static int process_renames(struct merge_options *opt,
-			   struct string_list *a_renames,
-			   struct string_list *b_renames)
-{
-	int clean_merge = 1, i, j;
-	struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
-	struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
-	const struct rename *sre;
-
-	/*
-	 * Note that as we build the list, we do not need to check if the
-	 * existing destination path is already in the list, because the
-	 * structure of diffcore_rename guarantees we won't have duplicates.
-	 */
-	for (i = 0; i < a_renames->nr; i++) {
-		sre = a_renames->items[i].util;
-		string_list_append(&a_by_dst, sre->pair->two->path)->util
-			= (void *)sre;
-	}
-	for (i = 0; i < b_renames->nr; i++) {
-		sre = b_renames->items[i].util;
-		string_list_append(&b_by_dst, sre->pair->two->path)->util
-			= (void *)sre;
-	}
-	string_list_sort(&a_by_dst);
-	string_list_sort(&b_by_dst);
-
-	for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
-		struct string_list *renames1, *renames2Dst;
-		struct rename *ren1 = NULL, *ren2 = NULL;
-		const char *ren1_src, *ren1_dst;
-		struct string_list_item *lookup;
-
-		if (i >= a_renames->nr) {
-			ren2 = b_renames->items[j++].util;
-		} else if (j >= b_renames->nr) {
-			ren1 = a_renames->items[i++].util;
-		} else {
-			int compare = strcmp(a_renames->items[i].string,
-					     b_renames->items[j].string);
-			if (compare <= 0)
-				ren1 = a_renames->items[i++].util;
-			if (compare >= 0)
-				ren2 = b_renames->items[j++].util;
-		}
-
-		/* TODO: refactor, so that 1/2 are not needed */
-		if (ren1) {
-			renames1 = a_renames;
-			renames2Dst = &b_by_dst;
-		} else {
-			renames1 = b_renames;
-			renames2Dst = &a_by_dst;
-			SWAP(ren2, ren1);
-		}
-
-		if (ren1->processed)
-			continue;
-		ren1->processed = 1;
-		ren1->dst_entry->processed = 1;
-		/* BUG: We should only mark src_entry as processed if we
-		 * are not dealing with a rename + add-source case.
-		 */
-		ren1->src_entry->processed = 1;
-
-		ren1_src = ren1->pair->one->path;
-		ren1_dst = ren1->pair->two->path;
-
-		if (ren2) {
-			/* One file renamed on both sides */
-			const char *ren2_src = ren2->pair->one->path;
-			const char *ren2_dst = ren2->pair->two->path;
-			enum rename_type rename_type;
-			if (strcmp(ren1_src, ren2_src) != 0)
-				BUG("ren1_src != ren2_src");
-			ren2->dst_entry->processed = 1;
-			ren2->processed = 1;
-			if (strcmp(ren1_dst, ren2_dst) != 0) {
-				rename_type = RENAME_ONE_FILE_TO_TWO;
-				clean_merge = 0;
-			} else {
-				rename_type = RENAME_ONE_FILE_TO_ONE;
-				/* BUG: We should only remove ren1_src in
-				 * the base stage (think of rename +
-				 * add-source cases).
-				 */
-				remove_file(opt, 1, ren1_src, 1);
-				update_entry(ren1->dst_entry,
-					     ren1->pair->one,
-					     ren1->pair->two,
-					     ren2->pair->two);
-			}
-			setup_rename_conflict_info(rename_type, opt, ren1, ren2);
-		} else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
-			/* Two different files renamed to the same thing */
-			char *ren2_dst;
-			ren2 = lookup->util;
-			ren2_dst = ren2->pair->two->path;
-			if (strcmp(ren1_dst, ren2_dst) != 0)
-				BUG("ren1_dst != ren2_dst");
-
-			clean_merge = 0;
-			ren2->processed = 1;
-			/*
-			 * BUG: We should only mark src_entry as processed
-			 * if we are not dealing with a rename + add-source
-			 * case.
-			 */
-			ren2->src_entry->processed = 1;
-
-			setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
-						   opt, ren1, ren2);
-		} else {
-			/* Renamed in 1, maybe changed in 2 */
-			/* we only use sha1 and mode of these */
-			struct diff_filespec src_other, dst_other;
-			int try_merge;
-
-			/*
-			 * unpack_trees loads entries from common-commit
-			 * into stage 1, from head-commit into stage 2, and
-			 * from merge-commit into stage 3.  We keep track
-			 * of which side corresponds to the rename.
-			 */
-			int renamed_stage = a_renames == renames1 ? 2 : 3;
-			int other_stage =   a_renames == renames1 ? 3 : 2;
-
-			/*
-			 * Directory renames have a funny corner case...
-			 */
-			int renamed_to_self = !strcmp(ren1_src, ren1_dst);
-
-			/* BUG: We should only remove ren1_src in the base
-			 * stage and in other_stage (think of rename +
-			 * add-source case).
-			 */
-			if (!renamed_to_self)
-				remove_file(opt, 1, ren1_src,
-					    renamed_stage == 2 ||
-					    !was_tracked(opt, ren1_src));
-
-			oidcpy(&src_other.oid,
-			       &ren1->src_entry->stages[other_stage].oid);
-			src_other.mode = ren1->src_entry->stages[other_stage].mode;
-			oidcpy(&dst_other.oid,
-			       &ren1->dst_entry->stages[other_stage].oid);
-			dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
-			try_merge = 0;
-
-			if (oideq(&src_other.oid, null_oid()) &&
-			    ren1->dir_rename_original_type == 'A') {
-				setup_rename_conflict_info(RENAME_VIA_DIR,
-							   opt, ren1, NULL);
-			} else if (renamed_to_self) {
-				setup_rename_conflict_info(RENAME_NORMAL,
-							   opt, ren1, NULL);
-			} else if (oideq(&src_other.oid, null_oid())) {
-				setup_rename_conflict_info(RENAME_DELETE,
-							   opt, ren1, NULL);
-			} else if ((dst_other.mode == ren1->pair->two->mode) &&
-				   oideq(&dst_other.oid, &ren1->pair->two->oid)) {
-				/*
-				 * Added file on the other side identical to
-				 * the file being renamed: clean merge.
-				 * Also, there is no need to overwrite the
-				 * file already in the working copy, so call
-				 * update_file_flags() instead of
-				 * update_file().
-				 */
-				if (update_file_flags(opt,
-						      ren1->pair->two,
-						      ren1_dst,
-						      1, /* update_cache */
-						      0  /* update_wd    */))
-					clean_merge = -1;
-			} else if (!oideq(&dst_other.oid, null_oid())) {
-				/*
-				 * Probably not a clean merge, but it's
-				 * premature to set clean_merge to 0 here,
-				 * because if the rename merges cleanly and
-				 * the merge exactly matches the newly added
-				 * file, then the merge will be clean.
-				 */
-				setup_rename_conflict_info(RENAME_ADD,
-							   opt, ren1, NULL);
-			} else
-				try_merge = 1;
-
-			if (clean_merge < 0)
-				goto cleanup_and_return;
-			if (try_merge) {
-				struct diff_filespec *o, *a, *b;
-				src_other.path = (char *)ren1_src;
-
-				o = ren1->pair->one;
-				if (a_renames == renames1) {
-					a = ren1->pair->two;
-					b = &src_other;
-				} else {
-					b = ren1->pair->two;
-					a = &src_other;
-				}
-				update_entry(ren1->dst_entry, o, a, b);
-				setup_rename_conflict_info(RENAME_NORMAL,
-							   opt, ren1, NULL);
-			}
-		}
-	}
-cleanup_and_return:
-	string_list_clear(&a_by_dst, 0);
-	string_list_clear(&b_by_dst, 0);
-
-	return clean_merge;
-}
-
-struct rename_info {
-	struct string_list *head_renames;
-	struct string_list *merge_renames;
-};
-
-static void initial_cleanup_rename(struct diff_queue_struct *pairs,
-				   struct hashmap *dir_renames)
-{
-	struct hashmap_iter iter;
-	struct dir_rename_entry *e;
-
-	hashmap_for_each_entry(dir_renames, &iter, e,
-				ent /* member name */) {
-		free(e->dir);
-		strbuf_release(&e->new_dir);
-		/* possible_new_dirs already cleared in get_directory_renames */
-	}
-	hashmap_clear_and_free(dir_renames, struct dir_rename_entry, ent);
-	free(dir_renames);
-
-	free(pairs->queue);
-	free(pairs);
-}
-
-static int detect_and_process_renames(struct merge_options *opt,
-				      struct tree *common,
-				      struct tree *head,
-				      struct tree *merge,
-				      struct string_list *entries,
-				      struct rename_info *ri)
-{
-	struct diff_queue_struct *head_pairs, *merge_pairs;
-	struct hashmap *dir_re_head, *dir_re_merge;
-	int clean = 1;
-
-	ri->head_renames = NULL;
-	ri->merge_renames = NULL;
-
-	if (!merge_detect_rename(opt))
-		return 1;
-
-	head_pairs = get_diffpairs(opt, common, head);
-	merge_pairs = get_diffpairs(opt, common, merge);
-
-	if ((opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE) ||
-	    (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
-	     !opt->priv->call_depth)) {
-		dir_re_head = get_directory_renames(head_pairs);
-		dir_re_merge = get_directory_renames(merge_pairs);
-
-		handle_directory_level_conflicts(opt,
-						 dir_re_head, head,
-						 dir_re_merge, merge);
-	} else {
-		dir_re_head  = xmalloc(sizeof(*dir_re_head));
-		dir_re_merge = xmalloc(sizeof(*dir_re_merge));
-		dir_rename_init(dir_re_head);
-		dir_rename_init(dir_re_merge);
-	}
-
-	ri->head_renames  = get_renames(opt, opt->branch1, head_pairs,
-					dir_re_merge, dir_re_head, head,
-					common, head, merge, entries,
-					&clean);
-	if (clean < 0)
-		goto cleanup;
-	ri->merge_renames = get_renames(opt, opt->branch2, merge_pairs,
-					dir_re_head, dir_re_merge, merge,
-					common, head, merge, entries,
-					&clean);
-	if (clean < 0)
-		goto cleanup;
-	clean &= process_renames(opt, ri->head_renames, ri->merge_renames);
-
-cleanup:
-	/*
-	 * Some cleanup is deferred until cleanup_renames() because the
-	 * data structures are still needed and referenced in
-	 * process_entry().  But there are a few things we can free now.
-	 */
-	initial_cleanup_rename(head_pairs, dir_re_head);
-	initial_cleanup_rename(merge_pairs, dir_re_merge);
-
-	return clean;
-}
-
-static void final_cleanup_rename(struct string_list *rename)
-{
-	const struct rename *re;
-	int i;
-
-	if (!rename)
-		return;
-
-	for (i = 0; i < rename->nr; i++) {
-		re = rename->items[i].util;
-		diff_free_filepair(re->pair);
-		if (re->src_entry->rename_conflict_info_owned)
-			FREE_AND_NULL(re->src_entry->rename_conflict_info);
-		if (re->dst_entry->rename_conflict_info_owned)
-			FREE_AND_NULL(re->dst_entry->rename_conflict_info);
-	}
-	string_list_clear(rename, 1);
-	free(rename);
-}
-
-static void final_cleanup_renames(struct rename_info *re_info)
-{
-	final_cleanup_rename(re_info->head_renames);
-	final_cleanup_rename(re_info->merge_renames);
-}
-
-static int read_oid_strbuf(struct merge_options *opt,
-			   const struct object_id *oid,
-			   struct strbuf *dst)
-{
-	void *buf;
-	enum object_type type;
-	unsigned long size;
-	buf = repo_read_object_file(the_repository, oid, &type, &size);
-	if (!buf)
-		return err(opt, _("cannot read object %s"), oid_to_hex(oid));
-	if (type != OBJ_BLOB) {
-		free(buf);
-		return err(opt, _("object %s is not a blob"), oid_to_hex(oid));
-	}
-	strbuf_attach(dst, buf, size, size + 1);
-	return 0;
-}
-
-static int blob_unchanged(struct merge_options *opt,
-			  const struct diff_filespec *o,
-			  const struct diff_filespec *a,
-			  int renormalize, const char *path)
-{
-	struct strbuf obuf = STRBUF_INIT;
-	struct strbuf abuf = STRBUF_INIT;
-	int ret = 0; /* assume changed for safety */
-	struct index_state *idx = opt->repo->index;
-
-	if (a->mode != o->mode)
-		return 0;
-	if (oideq(&o->oid, &a->oid))
-		return 1;
-	if (!renormalize)
-		return 0;
-
-	if (read_oid_strbuf(opt, &o->oid, &obuf) ||
-	    read_oid_strbuf(opt, &a->oid, &abuf))
-		goto error_return;
-	/*
-	 * Note: binary | is used so that both renormalizations are
-	 * performed.  Comparison can be skipped if both files are
-	 * unchanged since their sha1s have already been compared.
-	 */
-	if (renormalize_buffer(idx, path, obuf.buf, obuf.len, &obuf) |
-	    renormalize_buffer(idx, path, abuf.buf, abuf.len, &abuf))
-		ret = (obuf.len == abuf.len && !memcmp(obuf.buf, abuf.buf, obuf.len));
-
-error_return:
-	strbuf_release(&obuf);
-	strbuf_release(&abuf);
-	return ret;
-}
-
-static int handle_modify_delete(struct merge_options *opt,
-				const char *path,
-				const struct diff_filespec *o,
-				const struct diff_filespec *a,
-				const struct diff_filespec *b)
-{
-	const char *modify_branch, *delete_branch;
-	const struct diff_filespec *changed;
-
-	if (is_valid(a)) {
-		modify_branch = opt->branch1;
-		delete_branch = opt->branch2;
-		changed = a;
-	} else {
-		modify_branch = opt->branch2;
-		delete_branch = opt->branch1;
-		changed = b;
-	}
-
-	return handle_change_delete(opt,
-				    path, NULL,
-				    o, changed,
-				    modify_branch, delete_branch,
-				    _("modify"), _("modified"));
-}
-
-static int handle_content_merge(struct merge_file_info *mfi,
-				struct merge_options *opt,
-				const char *path,
-				int is_dirty,
-				const struct diff_filespec *o,
-				const struct diff_filespec *a,
-				const struct diff_filespec *b,
-				struct rename_conflict_info *ci)
-{
-	const char *reason = _("content");
-	unsigned df_conflict_remains = 0;
-
-	if (!is_valid(o))
-		reason = _("add/add");
-
-	assert(o->path && a->path && b->path);
-	if (ci && dir_in_way(opt->repo->index, path, !opt->priv->call_depth,
-			     S_ISGITLINK(ci->ren1->pair->two->mode)))
-		df_conflict_remains = 1;
-
-	if (merge_mode_and_contents(opt, o, a, b, path,
-				    opt->branch1, opt->branch2,
-				    opt->priv->call_depth * 2, mfi))
-		return -1;
-
-	/*
-	 * We can skip updating the working tree file iff:
-	 *   a) The merge is clean
-	 *   b) The merge matches what was in HEAD (content, mode, pathname)
-	 *   c) The target path is usable (i.e. not involved in D/F conflict)
-	 */
-	if (mfi->clean && was_tracked_and_matches(opt, path, &mfi->blob) &&
-	    !df_conflict_remains) {
-		int pos;
-		struct cache_entry *ce;
-
-		output(opt, 3, _("Skipped %s (merged same as existing)"), path);
-		if (add_cacheinfo(opt, &mfi->blob, path,
-				  0, (!opt->priv->call_depth && !is_dirty), 0))
-			return -1;
-		/*
-		 * However, add_cacheinfo() will delete the old cache entry
-		 * and add a new one.  We need to copy over any skip_worktree
-		 * flag to avoid making the file appear as if it were
-		 * deleted by the user.
-		 */
-		pos = index_name_pos(&opt->priv->orig_index, path, strlen(path));
-		ce = opt->priv->orig_index.cache[pos];
-		if (ce_skip_worktree(ce)) {
-			pos = index_name_pos(opt->repo->index, path, strlen(path));
-			ce = opt->repo->index->cache[pos];
-			ce->ce_flags |= CE_SKIP_WORKTREE;
-		}
-		return mfi->clean;
-	}
-
-	if (!mfi->clean) {
-		if (S_ISGITLINK(mfi->blob.mode))
-			reason = _("submodule");
-		output(opt, 1, _("CONFLICT (%s): Merge conflict in %s"),
-				reason, path);
-		if (ci && !df_conflict_remains)
-			if (update_stages(opt, path, o, a, b))
-				return -1;
-	}
-
-	if (df_conflict_remains || is_dirty) {
-		char *new_path;
-		if (opt->priv->call_depth) {
-			remove_file_from_index(opt->repo->index, path);
-		} else {
-			if (!mfi->clean) {
-				if (update_stages(opt, path, o, a, b))
-					return -1;
-			} else {
-				int file_from_stage2 = was_tracked(opt, path);
-
-				if (update_stages(opt, path, NULL,
-						  file_from_stage2 ? &mfi->blob : NULL,
-						  file_from_stage2 ? NULL : &mfi->blob))
-					return -1;
-			}
-
-		}
-		new_path = unique_path(opt, path, ci->ren1->branch);
-		if (is_dirty) {
-			output(opt, 1, _("Refusing to lose dirty file at %s"),
-			       path);
-		}
-		output(opt, 1, _("Adding as %s instead"), new_path);
-		if (update_file(opt, 0, &mfi->blob, new_path)) {
-			free(new_path);
-			return -1;
-		}
-		free(new_path);
-		mfi->clean = 0;
-	} else if (update_file(opt, mfi->clean, &mfi->blob, path))
-		return -1;
-	return !is_dirty && mfi->clean;
-}
-
-static int handle_rename_normal(struct merge_options *opt,
-				const char *path,
-				const struct diff_filespec *o,
-				const struct diff_filespec *a,
-				const struct diff_filespec *b,
-				struct rename_conflict_info *ci)
-{
-	struct rename *ren = ci->ren1;
-	struct merge_file_info mfi;
-	int clean;
-
-	/* Merge the content and write it out */
-	clean = handle_content_merge(&mfi, opt, path, was_dirty(opt, path),
-				     o, a, b, ci);
-
-	if (clean &&
-	    opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_CONFLICT &&
-	    ren->dir_rename_original_dest) {
-		if (update_stages(opt, path,
-				  &mfi.blob, &mfi.blob, &mfi.blob))
-			return -1;
-		clean = 0; /* not clean, but conflicted */
-	}
-	return clean;
-}
-
-static void dir_rename_warning(const char *msg,
-			       int is_add,
-			       int clean,
-			       struct merge_options *opt,
-			       struct rename *ren)
-{
-	const char *other_branch;
-	other_branch = (ren->branch == opt->branch1 ?
-			opt->branch2 : opt->branch1);
-	if (is_add) {
-		output(opt, clean ? 2 : 1, msg,
-		       ren->pair->one->path, ren->branch,
-		       other_branch, ren->pair->two->path);
-		return;
-	}
-	output(opt, clean ? 2 : 1, msg,
-	       ren->pair->one->path, ren->dir_rename_original_dest, ren->branch,
-	       other_branch, ren->pair->two->path);
-}
-static int warn_about_dir_renamed_entries(struct merge_options *opt,
-					  struct rename *ren)
-{
-	const char *msg;
-	int clean = 1, is_add;
-
-	if (!ren)
-		return clean;
-
-	/* Return early if ren was not affected/created by a directory rename */
-	if (!ren->dir_rename_original_dest)
-		return clean;
-
-	/* Sanity checks */
-	assert(opt->detect_directory_renames > MERGE_DIRECTORY_RENAMES_NONE);
-	assert(ren->dir_rename_original_type == 'A' ||
-	       ren->dir_rename_original_type == 'R');
-
-	/* Check whether to treat directory renames as a conflict */
-	clean = (opt->detect_directory_renames == MERGE_DIRECTORY_RENAMES_TRUE);
-
-	is_add = (ren->dir_rename_original_type == 'A');
-	if (ren->dir_rename_original_type == 'A' && clean) {
-		msg = _("Path updated: %s added in %s inside a "
-			"directory that was renamed in %s; moving it to %s.");
-	} else if (ren->dir_rename_original_type == 'A' && !clean) {
-		msg = _("CONFLICT (file location): %s added in %s "
-			"inside a directory that was renamed in %s, "
-			"suggesting it should perhaps be moved to %s.");
-	} else if (ren->dir_rename_original_type == 'R' && clean) {
-		msg = _("Path updated: %s renamed to %s in %s, inside a "
-			"directory that was renamed in %s; moving it to %s.");
-	} else if (ren->dir_rename_original_type == 'R' && !clean) {
-		msg = _("CONFLICT (file location): %s renamed to %s in %s, "
-			"inside a directory that was renamed in %s, "
-			"suggesting it should perhaps be moved to %s.");
-	} else {
-		BUG("Impossible dir_rename_original_type/clean combination");
-	}
-	dir_rename_warning(msg, is_add, clean, opt, ren);
-
-	return clean;
-}
-
-/* Per entry merge function */
-static int process_entry(struct merge_options *opt,
-			 const char *path, struct stage_data *entry)
-{
-	int clean_merge = 1;
-	int normalize = opt->renormalize;
-
-	struct diff_filespec *o = &entry->stages[1];
-	struct diff_filespec *a = &entry->stages[2];
-	struct diff_filespec *b = &entry->stages[3];
-	int o_valid = is_valid(o);
-	int a_valid = is_valid(a);
-	int b_valid = is_valid(b);
-	o->path = a->path = b->path = (char*)path;
-
-	entry->processed = 1;
-	if (entry->rename_conflict_info) {
-		struct rename_conflict_info *ci = entry->rename_conflict_info;
-		struct diff_filespec *temp;
-		int path_clean;
-
-		path_clean = warn_about_dir_renamed_entries(opt, ci->ren1);
-		path_clean &= warn_about_dir_renamed_entries(opt, ci->ren2);
-
-		/*
-		 * For cases with a single rename, {o,a,b}->path have all been
-		 * set to the rename target path; we need to set two of these
-		 * back to the rename source.
-		 * For rename/rename conflicts, we'll manually fix paths below.
-		 */
-		temp = (opt->branch1 == ci->ren1->branch) ? b : a;
-		o->path = temp->path = ci->ren1->pair->one->path;
-		if (ci->ren2) {
-			assert(opt->branch1 == ci->ren1->branch);
-		}
-
-		switch (ci->rename_type) {
-		case RENAME_NORMAL:
-		case RENAME_ONE_FILE_TO_ONE:
-			clean_merge = handle_rename_normal(opt, path, o, a, b,
-							   ci);
-			break;
-		case RENAME_VIA_DIR:
-			clean_merge = handle_rename_via_dir(opt, ci);
-			break;
-		case RENAME_ADD:
-			/*
-			 * Probably unclean merge, but if the renamed file
-			 * merges cleanly and the result can then be
-			 * two-way merged cleanly with the added file, I
-			 * guess it's a clean merge?
-			 */
-			clean_merge = handle_rename_add(opt, ci);
-			break;
-		case RENAME_DELETE:
-			clean_merge = 0;
-			if (handle_rename_delete(opt, ci))
-				clean_merge = -1;
-			break;
-		case RENAME_ONE_FILE_TO_TWO:
-			/*
-			 * Manually fix up paths; note:
-			 * ren[12]->pair->one->path are equal.
-			 */
-			o->path = ci->ren1->pair->one->path;
-			a->path = ci->ren1->pair->two->path;
-			b->path = ci->ren2->pair->two->path;
-
-			clean_merge = 0;
-			if (handle_rename_rename_1to2(opt, ci))
-				clean_merge = -1;
-			break;
-		case RENAME_TWO_FILES_TO_ONE:
-			/*
-			 * Manually fix up paths; note,
-			 * ren[12]->pair->two->path are actually equal.
-			 */
-			o->path = NULL;
-			a->path = ci->ren1->pair->two->path;
-			b->path = ci->ren2->pair->two->path;
-
-			/*
-			 * Probably unclean merge, but if the two renamed
-			 * files merge cleanly and the two resulting files
-			 * can then be two-way merged cleanly, I guess it's
-			 * a clean merge?
-			 */
-			clean_merge = handle_rename_rename_2to1(opt, ci);
-			break;
-		default:
-			entry->processed = 0;
-			break;
-		}
-		if (path_clean < clean_merge)
-			clean_merge = path_clean;
-	} else if (o_valid && (!a_valid || !b_valid)) {
-		/* Case A: Deleted in one */
-		if ((!a_valid && !b_valid) ||
-		    (!b_valid && blob_unchanged(opt, o, a, normalize, path)) ||
-		    (!a_valid && blob_unchanged(opt, o, b, normalize, path))) {
-			/* Deleted in both or deleted in one and
-			 * unchanged in the other */
-			if (a_valid)
-				output(opt, 2, _("Removing %s"), path);
-			/* do not touch working file if it did not exist */
-			remove_file(opt, 1, path, !a_valid);
-		} else {
-			/* Modify/delete; deleted side may have put a directory in the way */
-			clean_merge = 0;
-			if (handle_modify_delete(opt, path, o, a, b))
-				clean_merge = -1;
-		}
-	} else if ((!o_valid && a_valid && !b_valid) ||
-		   (!o_valid && !a_valid && b_valid)) {
-		/* Case B: Added in one. */
-		/* [nothing|directory] -> ([nothing|directory], file) */
-
-		const char *add_branch;
-		const char *other_branch;
-		const char *conf;
-		const struct diff_filespec *contents;
-
-		if (a_valid) {
-			add_branch = opt->branch1;
-			other_branch = opt->branch2;
-			contents = a;
-			conf = _("file/directory");
-		} else {
-			add_branch = opt->branch2;
-			other_branch = opt->branch1;
-			contents = b;
-			conf = _("directory/file");
-		}
-		if (dir_in_way(opt->repo->index, path,
-			       !opt->priv->call_depth && !S_ISGITLINK(a->mode),
-			       0)) {
-			char *new_path = unique_path(opt, path, add_branch);
-			clean_merge = 0;
-			output(opt, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
-			       "Adding %s as %s"),
-			       conf, path, other_branch, path, new_path);
-			if (update_file(opt, 0, contents, new_path))
-				clean_merge = -1;
-			else if (opt->priv->call_depth)
-				remove_file_from_index(opt->repo->index, path);
-			free(new_path);
-		} else {
-			output(opt, 2, _("Adding %s"), path);
-			/* do not overwrite file if already present */
-			if (update_file_flags(opt, contents, path, 1, !a_valid))
-				clean_merge = -1;
-		}
-	} else if (a_valid && b_valid) {
-		if (!o_valid) {
-			/* Case C: Added in both (check for same permissions) */
-			output(opt, 1,
-			       _("CONFLICT (add/add): Merge conflict in %s"),
-			       path);
-			clean_merge = handle_file_collision(opt,
-							    path, NULL, NULL,
-							    opt->branch1,
-							    opt->branch2,
-							    a, b);
-		} else {
-			/* case D: Modified in both, but differently. */
-			struct merge_file_info mfi;
-			int is_dirty = 0; /* unpack_trees would have bailed if dirty */
-			clean_merge = handle_content_merge(&mfi, opt, path,
-							   is_dirty,
-							   o, a, b, NULL);
-		}
-	} else if (!o_valid && !a_valid && !b_valid) {
-		/*
-		 * this entry was deleted altogether. a_mode == 0 means
-		 * we had that path and want to actively remove it.
-		 */
-		remove_file(opt, 1, path, !a->mode);
-	} else
-		BUG("fatal merge failure, shouldn't happen.");
-
-	return clean_merge;
-}
-
-static int merge_trees_internal(struct merge_options *opt,
-				struct tree *head,
-				struct tree *merge,
-				struct tree *merge_base,
-				struct tree **result)
-{
-	struct index_state *istate = opt->repo->index;
-	int code, clean;
-
-	if (opt->subtree_shift) {
-		merge = shift_tree_object(opt->repo, head, merge,
-					  opt->subtree_shift);
-		merge_base = shift_tree_object(opt->repo, head, merge_base,
-					       opt->subtree_shift);
-	}
-
-	if (oideq(&merge_base->object.oid, &merge->object.oid)) {
-		output(opt, 0, _("Already up to date."));
-		*result = head;
-		return 1;
-	}
-
-	code = unpack_trees_start(opt, merge_base, head, merge);
-
-	if (code != 0) {
-		if (show(opt, 4) || opt->priv->call_depth)
-			err(opt, _("merging of trees %s and %s failed"),
-			    oid_to_hex(&head->object.oid),
-			    oid_to_hex(&merge->object.oid));
-		unpack_trees_finish(opt);
-		return -1;
-	}
-
-	if (unmerged_index(istate)) {
-		struct string_list *entries;
-		struct rename_info re_info;
-		int i;
-		/*
-		 * Only need the hashmap while processing entries, so
-		 * initialize it here and free it when we are done running
-		 * through the entries. Keeping it in the merge_options as
-		 * opposed to decaring a local hashmap is for convenience
-		 * so that we don't have to pass it to around.
-		 */
-		hashmap_init(&opt->priv->current_file_dir_set, path_hashmap_cmp,
-			     NULL, 512);
-		get_files_dirs(opt, head);
-		get_files_dirs(opt, merge);
-
-		entries = get_unmerged(opt->repo->index);
-		clean = detect_and_process_renames(opt, merge_base, head, merge,
-						   entries, &re_info);
-		record_df_conflict_files(opt, entries);
-		if (clean < 0)
-			goto cleanup;
-		for (i = entries->nr-1; 0 <= i; i--) {
-			const char *path = entries->items[i].string;
-			struct stage_data *e = entries->items[i].util;
-			if (!e->processed) {
-				int ret = process_entry(opt, path, e);
-				if (!ret)
-					clean = 0;
-				else if (ret < 0) {
-					clean = ret;
-					goto cleanup;
-				}
-			}
-		}
-		for (i = 0; i < entries->nr; i++) {
-			struct stage_data *e = entries->items[i].util;
-			if (!e->processed)
-				BUG("unprocessed path??? %s",
-				    entries->items[i].string);
-		}
-
-	cleanup:
-		final_cleanup_renames(&re_info);
-
-		string_list_clear(entries, 1);
-		free(entries);
-
-		hashmap_clear_and_free(&opt->priv->current_file_dir_set,
-					struct path_hashmap_entry, e);
-
-		if (clean < 0) {
-			unpack_trees_finish(opt);
-			return clean;
-		}
-	}
-	else
-		clean = 1;
-
-	unpack_trees_finish(opt);
-
-	if (opt->priv->call_depth &&
-	    !(*result = write_in_core_index_as_tree(opt->repo)))
-		return -1;
-
-	return clean;
-}
-
-/*
- * Merge the commits h1 and h2, returning a flag (int) indicating the
- * cleanness of the merge.  Also, if opt->priv->call_depth, create a
- * virtual commit and write its location to *result.
- */
-static int merge_recursive_internal(struct merge_options *opt,
-				    struct commit *h1,
-				    struct commit *h2,
-				    const struct commit_list *_merge_bases,
-				    struct commit **result)
-{
-	struct commit_list *merge_bases = copy_commit_list(_merge_bases);
-	struct commit_list *iter;
-	struct commit *merged_merge_bases;
-	struct tree *result_tree;
-	const char *ancestor_name;
-	struct strbuf merge_base_abbrev = STRBUF_INIT;
-	int ret;
-
-	if (show(opt, 4)) {
-		output(opt, 4, _("Merging:"));
-		output_commit_title(opt, h1);
-		output_commit_title(opt, h2);
-	}
-
-	if (!merge_bases) {
-		if (repo_get_merge_bases(the_repository, h1, h2,
-					 &merge_bases) < 0) {
-			ret = -1;
-			goto out;
-		}
-		merge_bases = reverse_commit_list(merge_bases);
-	}
-
-	if (show(opt, 5)) {
-		unsigned cnt = commit_list_count(merge_bases);
-
-		output(opt, 5, Q_("found %u common ancestor:",
-				"found %u common ancestors:", cnt), cnt);
-		for (iter = merge_bases; iter; iter = iter->next)
-			output_commit_title(opt, iter->item);
-	}
-
-	merged_merge_bases = pop_commit(&merge_bases);
-	if (!merged_merge_bases) {
-		/* if there is no common ancestor, use an empty tree */
-		struct tree *tree;
-
-		tree = lookup_tree(opt->repo, opt->repo->hash_algo->empty_tree);
-		merged_merge_bases = make_virtual_commit(opt->repo, tree,
-							 "ancestor");
-		ancestor_name = "empty tree";
-	} else if (opt->ancestor && !opt->priv->call_depth) {
-		ancestor_name = opt->ancestor;
-	} else if (merge_bases) {
-		ancestor_name = "merged common ancestors";
-	} else {
-		strbuf_add_unique_abbrev(&merge_base_abbrev,
-					 &merged_merge_bases->object.oid,
-					 DEFAULT_ABBREV);
-		ancestor_name = merge_base_abbrev.buf;
-	}
-
-	for (iter = merge_bases; iter; iter = iter->next) {
-		const char *saved_b1, *saved_b2;
-		opt->priv->call_depth++;
-		/*
-		 * When the merge fails, the result contains files
-		 * with conflict markers. The cleanness flag is
-		 * ignored (unless indicating an error), it was never
-		 * actually used, as result of merge_trees has always
-		 * overwritten it: the committed "conflicts" were
-		 * already resolved.
-		 */
-		discard_index(opt->repo->index);
-		saved_b1 = opt->branch1;
-		saved_b2 = opt->branch2;
-		opt->branch1 = "Temporary merge branch 1";
-		opt->branch2 = "Temporary merge branch 2";
-		if (merge_recursive_internal(opt, merged_merge_bases, iter->item,
-					     NULL, &merged_merge_bases) < 0) {
-			ret = -1;
-			goto out;
-		}
-		opt->branch1 = saved_b1;
-		opt->branch2 = saved_b2;
-		opt->priv->call_depth--;
-
-		if (!merged_merge_bases) {
-			ret = err(opt, _("merge returned no commit"));
-			goto out;
-		}
-	}
-
-	/*
-	 * FIXME: Since merge_recursive_internal() is only ever called by
-	 * places that ensure the index is loaded first
-	 * (e.g. builtin/merge.c, rebase/sequencer, etc.), in the common
-	 * case where the merge base was unique that means when we get here
-	 * we immediately discard the index and re-read it, which is a
-	 * complete waste of time.  We should only be discarding and
-	 * re-reading if we were forced to recurse.
-	 */
-	discard_index(opt->repo->index);
-	if (!opt->priv->call_depth)
-		repo_read_index(opt->repo);
-
-	opt->ancestor = ancestor_name;
-	ret = merge_trees_internal(opt,
-				   repo_get_commit_tree(opt->repo, h1),
-				   repo_get_commit_tree(opt->repo, h2),
-				   repo_get_commit_tree(opt->repo,
-							merged_merge_bases),
-				   &result_tree);
-	opt->ancestor = NULL;  /* avoid accidental re-use of opt->ancestor */
-	if (ret < 0) {
-		flush_output(opt);
-		goto out;
-	}
-
-	if (opt->priv->call_depth) {
-		*result = make_virtual_commit(opt->repo, result_tree,
-					      "merged tree");
-		commit_list_insert(h1, &(*result)->parents);
-		commit_list_insert(h2, &(*result)->parents->next);
-	}
-
-out:
-	strbuf_release(&merge_base_abbrev);
-	free_commit_list(merge_bases);
-	return ret;
-}
-
-static int merge_start(struct merge_options *opt, struct tree *head)
-{
-	struct strbuf sb = STRBUF_INIT;
-
-	/* Sanity checks on opt */
-	assert(opt->repo);
-
-	assert(opt->branch1 && opt->branch2);
-
-	assert(opt->detect_renames >= -1 &&
-	       opt->detect_renames <= DIFF_DETECT_COPY);
-	assert(opt->detect_directory_renames >= MERGE_DIRECTORY_RENAMES_NONE &&
-	       opt->detect_directory_renames <= MERGE_DIRECTORY_RENAMES_TRUE);
-	assert(opt->rename_limit >= -1);
-	assert(opt->rename_score >= 0 && opt->rename_score <= MAX_SCORE);
-	assert(opt->show_rename_progress >= 0 && opt->show_rename_progress <= 1);
-
-	assert(opt->xdl_opts >= 0);
-	assert(opt->recursive_variant >= MERGE_VARIANT_NORMAL &&
-	       opt->recursive_variant <= MERGE_VARIANT_THEIRS);
-
-	assert(opt->verbosity >= 0 && opt->verbosity <= 5);
-	assert(opt->buffer_output <= 2);
-	assert(opt->obuf.len == 0);
-
-	assert(opt->priv == NULL);
-
-	/* Not supported; option specific to merge-ort */
-	assert(!opt->record_conflict_msgs_as_headers);
-	assert(!opt->msg_header_prefix);
-
-	/* Sanity check on repo state; index must match head */
-	if (repo_index_has_changes(opt->repo, head, &sb)) {
-		err(opt, _("Your local changes to the following files would be overwritten by merge:\n  %s"),
-		    sb.buf);
-		strbuf_release(&sb);
-		return -1;
-	}
-
-	CALLOC_ARRAY(opt->priv, 1);
-	string_list_init_dup(&opt->priv->df_conflict_file_set);
-	return 0;
-}
-
-static void merge_finalize(struct merge_options *opt)
-{
-	flush_output(opt);
-	if (!opt->priv->call_depth && opt->buffer_output < 2)
-		strbuf_release(&opt->obuf);
-	if (show(opt, 2))
-		diff_warn_rename_limit("merge.renamelimit",
-				       opt->priv->needed_rename_limit, 0);
-	hashmap_clear_and_free(&opt->priv->current_file_dir_set,
-			       struct path_hashmap_entry, e);
-	string_list_clear(&opt->priv->df_conflict_file_set, 0);
-	FREE_AND_NULL(opt->priv);
-}
-
-int merge_trees(struct merge_options *opt,
-		struct tree *head,
-		struct tree *merge,
-		struct tree *merge_base)
-{
-	int clean;
-	struct tree *ignored;
-
-	assert(opt->ancestor != NULL);
-
-	if (merge_start(opt, head))
-		return -1;
-	clean = merge_trees_internal(opt, head, merge, merge_base, &ignored);
-	merge_finalize(opt);
-
-	return clean;
-}
-
-int merge_recursive(struct merge_options *opt,
-		    struct commit *h1,
-		    struct commit *h2,
-		    const struct commit_list *merge_bases,
-		    struct commit **result)
-{
-	int clean;
-
-	assert(opt->ancestor == NULL ||
-	       !strcmp(opt->ancestor, "constructed merge base"));
-
-	prepare_repo_settings(opt->repo);
-	opt->repo->settings.command_requires_full_index = 1;
-
-	if (merge_start(opt, repo_get_commit_tree(opt->repo, h1)))
-		return -1;
-	clean = merge_recursive_internal(opt, h1, h2, merge_bases, result);
-	merge_finalize(opt);
-
-	return clean;
-}
-
-static struct commit *get_ref(struct repository *repo,
-			      const struct object_id *oid,
-			      const char *name)
-{
-	struct object *object;
-
-	object = deref_tag(repo, parse_object(repo, oid),
-			   name, strlen(name));
-	if (!object)
-		return NULL;
-	if (object->type == OBJ_TREE)
-		return make_virtual_commit(repo, (struct tree*)object, name);
-	if (object->type != OBJ_COMMIT)
-		return NULL;
-	if (repo_parse_commit(repo, (struct commit *)object))
-		return NULL;
-	return (struct commit *)object;
-}
-
-int merge_recursive_generic(struct merge_options *opt,
-			    const struct object_id *head,
-			    const struct object_id *merge,
-			    int num_merge_bases,
-			    const struct object_id *merge_bases,
-			    struct commit **result)
-{
-	int clean;
-	struct lock_file lock = LOCK_INIT;
-	struct commit *head_commit = get_ref(opt->repo, head, opt->branch1);
-	struct commit *next_commit = get_ref(opt->repo, merge, opt->branch2);
-	struct commit_list *ca = NULL;
-
-	if (merge_bases) {
-		int i;
-		for (i = 0; i < num_merge_bases; ++i) {
-			struct commit *base;
-			if (!(base = get_ref(opt->repo, &merge_bases[i],
-					     oid_to_hex(&merge_bases[i]))))
-				return err(opt, _("Could not parse object '%s'"),
-					   oid_to_hex(&merge_bases[i]));
-			commit_list_insert(base, &ca);
-		}
-		if (num_merge_bases == 1)
-			opt->ancestor = "constructed merge base";
-	}
-
-	repo_hold_locked_index(opt->repo, &lock, LOCK_DIE_ON_ERROR);
-	clean = merge_recursive(opt, head_commit, next_commit, ca,
-				result);
-	free_commit_list(ca);
-	if (clean < 0) {
-		rollback_lock_file(&lock);
-		return clean;
-	}
-
-	if (write_locked_index(opt->repo->index, &lock,
-			       COMMIT_LOCK | SKIP_IF_UNCHANGED))
-		return err(opt, _("Unable to write index."));
-
-	return clean ? 0 : 1;
-}
-
-static void merge_recursive_config(struct merge_options *opt, int ui)
-{
-	char *value = NULL;
-	int renormalize = 0;
-	git_config_get_int("merge.verbosity", &opt->verbosity);
-	git_config_get_int("diff.renamelimit", &opt->rename_limit);
-	git_config_get_int("merge.renamelimit", &opt->rename_limit);
-	git_config_get_bool("merge.renormalize", &renormalize);
-	opt->renormalize = renormalize;
-	if (!git_config_get_string("diff.renames", &value)) {
-		opt->detect_renames = git_config_rename("diff.renames", value);
-		free(value);
-	}
-	if (!git_config_get_string("merge.renames", &value)) {
-		opt->detect_renames = git_config_rename("merge.renames", value);
-		free(value);
-	}
-	if (!git_config_get_string("merge.directoryrenames", &value)) {
-		int boolval = git_parse_maybe_bool(value);
-		if (0 <= boolval) {
-			opt->detect_directory_renames = boolval ?
-				MERGE_DIRECTORY_RENAMES_TRUE :
-				MERGE_DIRECTORY_RENAMES_NONE;
-		} else if (!strcasecmp(value, "conflict")) {
-			opt->detect_directory_renames =
-				MERGE_DIRECTORY_RENAMES_CONFLICT;
-		} /* avoid erroring on values from future versions of git */
-		free(value);
-	}
-	if (ui) {
-		if (!git_config_get_string("diff.algorithm", &value)) {
-			long diff_algorithm = parse_algorithm_value(value);
-			if (diff_algorithm < 0)
-				die(_("unknown value for config '%s': %s"), "diff.algorithm", value);
-			opt->xdl_opts = (opt->xdl_opts & ~XDF_DIFF_ALGORITHM_MASK) | diff_algorithm;
-			free(value);
-		}
-	}
-	git_config(git_xmerge_config, NULL);
-}
-
-static void init_merge_options(struct merge_options *opt,
-			struct repository *repo, int ui)
-{
-	const char *merge_verbosity;
-	memset(opt, 0, sizeof(struct merge_options));
-
-	opt->repo = repo;
-
-	opt->detect_renames = -1;
-	opt->detect_directory_renames = MERGE_DIRECTORY_RENAMES_CONFLICT;
-	opt->rename_limit = -1;
-
-	opt->verbosity = 2;
-	opt->buffer_output = 1;
-	strbuf_init(&opt->obuf, 0);
-
-	opt->renormalize = 0;
-
-	opt->conflict_style = -1;
-	opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
-
-	merge_recursive_config(opt, ui);
-	merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
-	if (merge_verbosity)
-		opt->verbosity = strtol(merge_verbosity, NULL, 10);
-	if (opt->verbosity >= 5)
-		opt->buffer_output = 0;
-}
-
-void init_ui_merge_options(struct merge_options *opt,
-			struct repository *repo)
-{
-	init_merge_options(opt, repo, 1);
-}
-
-void init_basic_merge_options(struct merge_options *opt,
-			struct repository *repo)
-{
-	init_merge_options(opt, repo, 0);
-}
-
-/*
- * For now, members of merge_options do not need deep copying, but
- * it may change in the future, in which case we would need to update
- * this, and also make a matching change to clear_merge_options() to
- * release the resources held by a copied instance.
- */
-void copy_merge_options(struct merge_options *dst, struct merge_options *src)
-{
-	*dst = *src;
-}
-
-void clear_merge_options(struct merge_options *opt UNUSED)
-{
-	; /* no-op as our copy is shallow right now */
-}
-
-int parse_merge_opt(struct merge_options *opt, const char *s)
-{
-	const char *arg;
-
-	if (!s || !*s)
-		return -1;
-	if (!strcmp(s, "ours"))
-		opt->recursive_variant = MERGE_VARIANT_OURS;
-	else if (!strcmp(s, "theirs"))
-		opt->recursive_variant = MERGE_VARIANT_THEIRS;
-	else if (!strcmp(s, "subtree"))
-		opt->subtree_shift = "";
-	else if (skip_prefix(s, "subtree=", &arg))
-		opt->subtree_shift = arg;
-	else if (!strcmp(s, "patience"))
-		opt->xdl_opts = DIFF_WITH_ALG(opt, PATIENCE_DIFF);
-	else if (!strcmp(s, "histogram"))
-		opt->xdl_opts = DIFF_WITH_ALG(opt, HISTOGRAM_DIFF);
-	else if (skip_prefix(s, "diff-algorithm=", &arg)) {
-		long value = parse_algorithm_value(arg);
-		if (value < 0)
-			return -1;
-		/* clear out previous settings */
-		DIFF_XDL_CLR(opt, NEED_MINIMAL);
-		opt->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
-		opt->xdl_opts |= value;
-	}
-	else if (!strcmp(s, "ignore-space-change"))
-		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_CHANGE);
-	else if (!strcmp(s, "ignore-all-space"))
-		DIFF_XDL_SET(opt, IGNORE_WHITESPACE);
-	else if (!strcmp(s, "ignore-space-at-eol"))
-		DIFF_XDL_SET(opt, IGNORE_WHITESPACE_AT_EOL);
-	else if (!strcmp(s, "ignore-cr-at-eol"))
-		DIFF_XDL_SET(opt, IGNORE_CR_AT_EOL);
-	else if (!strcmp(s, "renormalize"))
-		opt->renormalize = 1;
-	else if (!strcmp(s, "no-renormalize"))
-		opt->renormalize = 0;
-	else if (!strcmp(s, "no-renames"))
-		opt->detect_renames = 0;
-	else if (!strcmp(s, "find-renames")) {
-		opt->detect_renames = 1;
-		opt->rename_score = 0;
-	}
-	else if (skip_prefix(s, "find-renames=", &arg) ||
-		 skip_prefix(s, "rename-threshold=", &arg)) {
-		if ((opt->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
-			return -1;
-		opt->detect_renames = 1;
-	}
-	/*
-	 * Please update $__git_merge_strategy_options in
-	 * git-completion.bash when you add new options
-	 */
-	else
-		return -1;
-	return 0;
-}
diff --git a/merge-recursive.h b/merge-recursive.h
deleted file mode 100644
index 0b91f28f902..00000000000
--- a/merge-recursive.h
+++ /dev/null
@@ -1,132 +0,0 @@
-#ifndef MERGE_RECURSIVE_H
-#define MERGE_RECURSIVE_H
-
-#include "strbuf.h"
-
-struct commit;
-struct commit_list;
-struct object_id;
-struct repository;
-struct tree;
-
-struct merge_options_internal;
-struct merge_options {
-	struct repository *repo;
-
-	/* ref names used in console messages and conflict markers */
-	const char *ancestor;
-	const char *branch1;
-	const char *branch2;
-
-	/* rename related options */
-	int detect_renames;
-	enum {
-		MERGE_DIRECTORY_RENAMES_NONE = 0,
-		MERGE_DIRECTORY_RENAMES_CONFLICT = 1,
-		MERGE_DIRECTORY_RENAMES_TRUE = 2
-	} detect_directory_renames;
-	int rename_limit;
-	int rename_score;
-	int show_rename_progress;
-
-	/* xdiff-related options (patience, ignore whitespace, ours/theirs) */
-	long xdl_opts;
-	int conflict_style;
-	enum {
-		MERGE_VARIANT_NORMAL = 0,
-		MERGE_VARIANT_OURS,
-		MERGE_VARIANT_THEIRS
-	} recursive_variant;
-
-	/* console output related options */
-	int verbosity;
-	unsigned buffer_output; /* 1: output at end, 2: keep buffered */
-	struct strbuf obuf;     /* output buffer; if buffer_output == 2, caller
-				 * must handle and call strbuf_release */
-
-	/* miscellaneous control options */
-	const char *subtree_shift;
-	unsigned renormalize : 1;
-	unsigned record_conflict_msgs_as_headers : 1;
-	const char *msg_header_prefix;
-
-	/* internal fields used by the implementation */
-	struct merge_options_internal *priv;
-};
-
-/* for use by porcelain commands */
-void init_ui_merge_options(struct merge_options *opt, struct repository *repo);
-/* for use by plumbing commands */
-void init_basic_merge_options(struct merge_options *opt, struct repository *repo);
-
-void copy_merge_options(struct merge_options *dst, struct merge_options *src);
-void clear_merge_options(struct merge_options *opt);
-
-/* parse the option in s and update the relevant field of opt */
-int parse_merge_opt(struct merge_options *opt, const char *s);
-
-/*
- * RETURN VALUES: All the merge_* functions below return a value as follows:
- *   > 0     Merge was clean
- *   = 0     Merge had conflicts
- *   < 0     Merge hit an unexpected and unrecoverable problem (e.g. disk
- *             full) and aborted merge part-way through.
- */
-
-/*
- * rename-detecting three-way merge, no recursion.
- *
- * Outputs:
- *   - See RETURN VALUES above
- *   - opt->repo->index has the new index
- *   - new index NOT written to disk
- *   - The working tree is updated with results of the merge
- */
-int merge_trees(struct merge_options *opt,
-		struct tree *head,
-		struct tree *merge,
-		struct tree *merge_base);
-
-/*
- * merge_recursive is like merge_trees() but with recursive ancestor
- * consolidation.
- *
- * NOTE: empirically, about a decade ago it was determined that with more
- *       than two merge bases, optimal behavior was found when the
- *       merge_bases were passed in the order of oldest commit to newest
- *       commit.  Also, merge_bases will be consumed (emptied) so make a
- *       copy if you need it.
- *
- * Outputs:
- *   - See RETURN VALUES above
- *   - *result is treated as scratch space for temporary recursive merges
- *   - opt->repo->index has the new index
- *   - new index NOT written to disk
- *   - The working tree is updated with results of the merge
- */
-int merge_recursive(struct merge_options *opt,
-		    struct commit *h1,
-		    struct commit *h2,
-		    const struct commit_list *merge_bases,
-		    struct commit **result);
-
-/*
- * merge_recursive_generic can operate on trees instead of commits, by
- * wrapping the trees into virtual commits, and calling merge_recursive().
- * It also writes out the in-memory index to disk if the merge is successful.
- *
- * Outputs:
- *   - See RETURN VALUES above
- *   - *result is treated as scratch space for temporary recursive merges
- *   - opt->repo->index has the new index
- *   - new index also written to $GIT_INDEX_FILE on disk
- *   - The working tree is updated with results of the merge
- */
-int merge_recursive_generic(struct merge_options *opt,
-			    const struct object_id *head,
-			    const struct object_id *merge,
-			    int num_merge_bases,
-			    const struct object_id *merge_bases,
-			    struct commit **result);
-
-#endif
diff --git a/meson.build b/meson.build
index e98cfa4909f..8448df9d15e 100644
--- a/meson.build
+++ b/meson.build
@@ -338,7 +338,6 @@ libgit_sources = [
   'merge-ll.c',
   'merge-ort.c',
   'merge-ort-wrappers.c',
-  'merge-recursive.c',
   'merge.c',
   'midx.c',
   'midx-write.c',
-- 
gitgitgadget