1 files changed, 589 insertions, 259 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index 856e98c083..db9ba19ddf 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -20,6 +20,7 @@
 #include "attr.h"
 #include "merge-recursive.h"
 #include "dir.h"
+#include "submodule.h"
 
 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
 				      const char *subtree_shift)
@@ -62,20 +63,62 @@ static int sha_eq(const unsigned char *a, const unsigned char *b)
 	return a && b && hashcmp(a, b) == 0;
 }
 
+enum rename_type {
+	RENAME_NORMAL = 0,
+	RENAME_DELETE,
+	RENAME_ONE_FILE_TO_TWO
+};
+
+struct rename_df_conflict_info {
+	enum rename_type rename_type;
+	struct diff_filepair *pair1;
+	struct diff_filepair *pair2;
+	const char *branch1;
+	const char *branch2;
+	struct stage_data *dst_entry1;
+	struct stage_data *dst_entry2;
+};
+
 /*
  * Since we want to write the index eventually, we cannot reuse the index
  * for these (temporary) data.
  */
-struct stage_data
-{
-	struct
-	{
+struct stage_data {
+	struct {
 		unsigned mode;
 		unsigned char sha[20];
 	} stages[4];
+	struct rename_df_conflict_info *rename_df_conflict_info;
 	unsigned processed:1;
 };
 
+static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
+						 struct diff_filepair *pair1,
+						 struct diff_filepair *pair2,
+						 const char *branch1,
+						 const char *branch2,
+						 struct stage_data *dst_entry1,
+						 struct stage_data *dst_entry2)
+{
+	struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
+	ci->rename_type = rename_type;
+	ci->pair1 = pair1;
+	ci->branch1 = branch1;
+	ci->branch2 = branch2;
+
+	ci->dst_entry1 = dst_entry1;
+	dst_entry1->rename_df_conflict_info = ci;
+	dst_entry1->processed = 0;
+
+	assert(!pair2 == !dst_entry2);
+	if (dst_entry2) {
+		ci->dst_entry2 = dst_entry2;
+		ci->pair2 = pair2;
+		dst_entry2->rename_df_conflict_info = ci;
+		dst_entry2->processed = 0;
+	}
+}
+
 static int show(struct merge_options *o, int v)
 {
 	return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
@@ -92,7 +135,6 @@ static void flush_output(struct merge_options *o)
 __attribute__((format (printf, 3, 4)))
 static void output(struct merge_options *o, int v, const char *fmt, ...)
 {
-	int len;
 	va_list ap;
 
 	if (!show(o, v))
@@ -103,21 +145,9 @@ static void output(struct merge_options *o, int v, const char *fmt, ...)
 	strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 
 	va_start(ap, fmt);
-	len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
+	strbuf_vaddf(&o->obuf, fmt, ap);
 	va_end(ap);
 
-	if (len < 0)
-		len = 0;
-	if (len >= strbuf_avail(&o->obuf)) {
-		strbuf_grow(&o->obuf, len + 2);
-		va_start(ap, fmt);
-		len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
-		va_end(ap);
-		if (len >= strbuf_avail(&o->obuf)) {
-			die("this should not happen, your snprintf is broken");
-		}
-	}
-	strbuf_setlen(&o->obuf, o->obuf.len + len);
 	strbuf_add(&o->obuf, "\n", 1);
 	if (!o->buffer_output)
 		flush_output(o);
@@ -136,16 +166,10 @@ static void output_commit_title(struct merge_options *o, struct commit *commit)
 		if (parse_commit(commit) != 0)
 			printf("(bad commit)\n");
 		else {
-			const char *s;
-			int len;
-			for (s = commit->buffer; *s; s++)
-				if (*s == '\n' && s[1] == '\n') {
-					s += 2;
-					break;
-				}
-			for (len = 0; s[len] && '\n' != s[len]; len++)
-				; /* do nothing */
-			printf("%.*s\n", len, s);
+			const char *title;
+			int len = find_commit_subject(commit->buffer, &title);
+			if (len)
+				printf("%.*s\n", len, title);
 		}
 	}
 }
@@ -185,7 +209,7 @@ static int git_merge_trees(int index_only,
 	opts.fn = threeway_merge;
 	opts.src_index = &the_index;
 	opts.dst_index = &the_index;
-	opts.msgs = get_porcelain_error_msgs();
+	setup_unpack_trees_porcelain(&opts, "merge");
 
 	init_tree_desc_from_tree(t+0, common);
 	init_tree_desc_from_tree(t+1, head);
@@ -249,7 +273,9 @@ static int save_files_dirs(const unsigned char *sha1,
 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 {
 	int n;
-	if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
+	struct pathspec match_all;
+	init_pathspec(&match_all, NULL);
+	if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
 		return 0;
 	n = o->current_file_set.nr + o->current_directory_set.nr;
 	return n;
@@ -307,8 +333,62 @@ static struct string_list *get_unmerged(void)
 	return unmerged;
 }
 
-struct rename
+static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
+						      struct string_list *entries)
 {
+	/* If there are D/F conflicts, and the paths currently exist
+	 * in the working copy as a file, we want to remove them to
+	 * make room for the corresponding directory.  Such paths will
+	 * later be processed in process_df_entry() at the end.  If
+	 * the corresponding directory ends up being removed by the
+	 * merge, then the file will be reinstated at that time;
+	 * otherwise, if the file is not supposed to be removed by the
+	 * merge, the contents of the file will be placed in another
+	 * unique filename.
+	 *
+	 * NOTE: This function relies on the fact that entries for a
+	 * D/F conflict will appear adjacent in the index, with the
+	 * entries for the file appearing before entries for paths
+	 * below the corresponding directory.
+	 */
+	const char *last_file = NULL;
+	int last_len = 0;
+	int i;
+
+	for (i = 0; i < entries->nr; i++) {
+		const char *path = entries->items[i].string;
+		int len = strlen(path);
+		struct stage_data *e = 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, remove last_file to make room for path and friends.
+		 */
+		if (last_file &&
+		    len > last_len &&
+		    memcmp(path, last_file, last_len) == 0 &&
+		    path[last_len] == '/') {
+			output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
+			unlink(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;
+		}
+	}
+}
+
+struct rename {
 	struct diff_filepair *pair;
 	struct stage_data *src_entry;
 	struct stage_data *dst_entry;
@@ -338,13 +418,16 @@ static struct string_list *get_renames(struct merge_options *o,
 	opts.detect_rename = DIFF_DETECT_RENAME;
 	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
-			    500;
-	opts.warn_on_too_large_rename = 1;
+			    1000;
+	opts.rename_score = o->rename_score;
+	opts.show_rename_progress = o->show_rename_progress;
 	opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 	if (diff_setup_done(&opts) < 0)
 		die("diff setup failed");
 	diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 	diffcore_std(&opts);
+	if (opts.needed_rename_limit > o->needed_rename_limit)
+		o->needed_rename_limit = opts.needed_rename_limit;
 	for (i = 0; i < diff_queued_diff.nr; ++i) {
 		struct string_list_item *item;
 		struct rename *re;
@@ -378,11 +461,10 @@ static struct string_list *get_renames(struct merge_options *o,
 	return renames;
 }
 
-static int update_stages(const char *path, struct diff_filespec *o,
+static int update_stages_options(const char *path, struct diff_filespec *o,
 			 struct diff_filespec *a, struct diff_filespec *b,
-			 int clear)
+			 int clear, int options)
 {
-	int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 	if (clear)
 		if (remove_file_from_cache(path))
 			return -1;
@@ -398,6 +480,34 @@ static int update_stages(const char *path, struct diff_filespec *o,
 	return 0;
 }
 
+static int update_stages(const char *path, struct diff_filespec *o,
+			 struct diff_filespec *a, struct diff_filespec *b,
+			 int clear)
+{
+	int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
+	return update_stages_options(path, o, a, b, clear, options);
+}
+
+static int update_stages_and_entry(const char *path,
+				   struct stage_data *entry,
+				   struct diff_filespec *o,
+				   struct diff_filespec *a,
+				   struct diff_filespec *b,
+				   int clear)
+{
+	int options;
+
+	entry->processed = 0;
+	entry->stages[1].mode = o->mode;
+	entry->stages[2].mode = a->mode;
+	entry->stages[3].mode = b->mode;
+	hashcpy(entry->stages[1].sha, o->sha1);
+	hashcpy(entry->stages[2].sha, a->sha1);
+	hashcpy(entry->stages[3].sha, b->sha1);
+	options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
+	return update_stages_options(path, o, a, b, clear, options);
+}
+
 static int remove_file(struct merge_options *o, int clean,
 		       const char *path, int no_wd)
 {
@@ -525,13 +635,15 @@ static void update_file_flags(struct merge_options *o,
 		void *buf;
 		unsigned long size;
 
-		if (S_ISGITLINK(mode))
+		if (S_ISGITLINK(mode)) {
 			/*
 			 * We may later decide to recursively descend into
 			 * the submodule directory and update its index
 			 * and/or work tree, but we do not do that now.
 			 */
+			update_wd = 0;
 			goto update_index;
+		}
 
 		buf = read_sha1_file(sha, &type, &size);
 		if (!buf)
@@ -591,8 +703,7 @@ static void update_file(struct merge_options *o,
 
 /* Low level file merging, update and removal */
 
-struct merge_file_info
-{
+struct merge_file_info {
 	unsigned char sha[20];
 	unsigned mode;
 	unsigned clean:1,
@@ -608,22 +719,26 @@ static int merge_3way(struct merge_options *o,
 		      const char *branch2)
 {
 	mmfile_t orig, src1, src2;
+	struct ll_merge_options ll_opts = {0};
 	char *base_name, *name1, *name2;
 	int merge_status;
-	int favor;
 
-	if (o->call_depth)
-		favor = 0;
-	else {
+	ll_opts.renormalize = o->renormalize;
+	ll_opts.xdl_opts = o->xdl_opts;
+
+	if (o->call_depth) {
+		ll_opts.virtual_ancestor = 1;
+		ll_opts.variant = 0;
+	} else {
 		switch (o->recursive_variant) {
 		case MERGE_RECURSIVE_OURS:
-			favor = XDL_MERGE_FAVOR_OURS;
+			ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 			break;
 		case MERGE_RECURSIVE_THEIRS:
-			favor = XDL_MERGE_FAVOR_THEIRS;
+			ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 			break;
 		default:
-			favor = 0;
+			ll_opts.variant = 0;
 			break;
 		}
 	}
@@ -646,8 +761,7 @@ static int merge_3way(struct merge_options *o,
 	read_mmblob(&src2, b->sha1);
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
-				&src1, name1, &src2, name2,
-				(!!o->call_depth) | (favor << 1));
+				&src1, name1, &src2, name2, &ll_opts);
 
 	free(name1);
 	free(name2);
@@ -716,8 +830,8 @@ static struct merge_file_info merge_file(struct merge_options *o,
 			free(result_buf.ptr);
 			result.clean = (merge_status == 0);
 		} else if (S_ISGITLINK(a->mode)) {
-			result.clean = 0;
-			hashcpy(result.sha, a->sha1);
+			result.clean = merge_submodule(result.sha, one->path, one->sha1,
+						       a->sha1, b->sha1);
 		} else if (S_ISLNK(a->mode)) {
 			hashcpy(result.sha, a->sha1);
 
@@ -731,29 +845,56 @@ static struct merge_file_info merge_file(struct merge_options *o,
 	return result;
 }
 
-static void conflict_rename_rename(struct merge_options *o,
-				   struct rename *ren1,
-				   const char *branch1,
-				   struct rename *ren2,
-				   const char *branch2)
+static void conflict_rename_delete(struct merge_options *o,
+				   struct diff_filepair *pair,
+				   const char *rename_branch,
+				   const char *other_branch)
 {
+	char *dest_name = pair->two->path;
+	int df_conflict = 0;
+	struct stat st;
+
+	output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
+	       "and deleted in %s",
+	       pair->one->path, pair->two->path, rename_branch,
+	       other_branch);
+	if (!o->call_depth)
+		update_stages(dest_name, NULL,
+			      rename_branch == o->branch1 ? pair->two : NULL,
+			      rename_branch == o->branch1 ? NULL : pair->two,
+			      1);
+	if (lstat(dest_name, &st) == 0 && S_ISDIR(st.st_mode)) {
+		dest_name = unique_path(o, dest_name, rename_branch);
+		df_conflict = 1;
+	}
+	update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
+	if (df_conflict)
+		free(dest_name);
+}
+
+static void conflict_rename_rename_1to2(struct merge_options *o,
+					struct diff_filepair *pair1,
+					const char *branch1,
+					struct diff_filepair *pair2,
+					const char *branch2)
+{
+	/* One file was renamed in both branches, but to different names. */
 	char *del[2];
 	int delp = 0;
-	const char *ren1_dst = ren1->pair->two->path;
-	const char *ren2_dst = ren2->pair->two->path;
+	const char *ren1_dst = pair1->two->path;
+	const char *ren2_dst = pair2->two->path;
 	const char *dst_name1 = ren1_dst;
 	const char *dst_name2 = ren2_dst;
-	if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
+	struct stat st;
+	if (lstat(ren1_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 		dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 		output(o, 1, "%s is a directory in %s adding as %s instead",
 		       ren1_dst, branch2, dst_name1);
-		remove_file(o, 0, ren1_dst, 0);
 	}
-	if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
+	if (lstat(ren2_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 		dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 		output(o, 1, "%s is a directory in %s adding as %s instead",
 		       ren2_dst, branch1, dst_name2);
-		remove_file(o, 0, ren2_dst, 0);
 	}
 	if (o->call_depth) {
 		remove_file_from_cache(dst_name1);
@@ -761,34 +902,27 @@ static void conflict_rename_rename(struct merge_options *o,
 		/*
 		 * Uncomment to leave the conflicting names in the resulting tree
 		 *
-		 * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
-		 * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
+		 * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
+		 * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 		 */
 	} else {
-		update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
-		update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
+		update_stages(ren1_dst, NULL, pair1->two, NULL, 1);
+		update_stages(ren2_dst, NULL, NULL, pair2->two, 1);
+
+		update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
+		update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 	}
 	while (delp--)
 		free(del[delp]);
 }
 
-static void conflict_rename_dir(struct merge_options *o,
-				struct rename *ren1,
-				const char *branch1)
-{
-	char *new_path = unique_path(o, ren1->pair->two->path, branch1);
-	output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
-	remove_file(o, 0, ren1->pair->two->path, 0);
-	update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
-	free(new_path);
-}
-
-static void conflict_rename_rename_2(struct merge_options *o,
-				     struct rename *ren1,
-				     const char *branch1,
-				     struct rename *ren2,
-				     const char *branch2)
+static void conflict_rename_rename_2to1(struct merge_options *o,
+					struct rename *ren1,
+					const char *branch1,
+					struct rename *ren2,
+					const char *branch2)
 {
+	/* Two files were renamed to the same thing. */
 	char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 	char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 	output(o, 1, "Renaming %s to %s and %s to %s instead",
@@ -806,7 +940,8 @@ static int process_renames(struct merge_options *o,
 			   struct string_list *b_renames)
 {
 	int clean_merge = 1, i, j;
-	struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
+	struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
+	struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 	const struct rename *sre;
 
 	for (i = 0; i < a_renames->nr; i++) {
@@ -821,7 +956,6 @@ static int process_renames(struct merge_options *o,
 	}
 
 	for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
-		char *src;
 		struct string_list *renames1, *renames2Dst;
 		struct rename *ren1 = NULL, *ren2 = NULL;
 		const char *branch1, *branch2;
@@ -856,7 +990,6 @@ static int process_renames(struct merge_options *o,
 			ren2 = ren1;
 			ren1 = tmp;
 		}
-		src = ren1->pair->one->path;
 
 		ren1->dst_entry->processed = 1;
 		ren1->src_entry->processed = 1;
@@ -877,84 +1010,66 @@ static int process_renames(struct merge_options *o,
 			ren2->dst_entry->processed = 1;
 			ren2->processed = 1;
 			if (strcmp(ren1_dst, ren2_dst) != 0) {
-				clean_merge = 0;
-				output(o, 1, "CONFLICT (rename/rename): "
-				       "Rename \"%s\"->\"%s\" in branch \"%s\" "
-				       "rename \"%s\"->\"%s\" in \"%s\"%s",
-				       src, ren1_dst, branch1,
-				       src, ren2_dst, branch2,
-				       o->call_depth ? " (left unresolved)": "");
-				if (o->call_depth) {
-					remove_file_from_cache(src);
-					update_file(o, 0, ren1->pair->one->sha1,
-						    ren1->pair->one->mode, src);
-				}
-				conflict_rename_rename(o, ren1, branch1, ren2, branch2);
+				setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
+							      ren1->pair,
+							      ren2->pair,
+							      branch1,
+							      branch2,
+							      ren1->dst_entry,
+							      ren2->dst_entry);
 			} else {
-				struct merge_file_info mfi;
 				remove_file(o, 1, ren1_src, 1);
-				mfi = merge_file(o,
-						 ren1->pair->one,
-						 ren1->pair->two,
-						 ren2->pair->two,
-						 branch1,
-						 branch2);
-				if (mfi.merge || !mfi.clean)
-					output(o, 1, "Renaming %s->%s", src, ren1_dst);
-
-				if (mfi.merge)
-					output(o, 2, "Auto-merging %s", ren1_dst);
-
-				if (!mfi.clean) {
-					output(o, 1, "CONFLICT (content): merge conflict in %s",
-					       ren1_dst);
-					clean_merge = 0;
-
-					if (!o->call_depth)
-						update_stages(ren1_dst,
-							      ren1->pair->one,
-							      ren1->pair->two,
-							      ren2->pair->two,
-							      1 /* clear */);
-				}
-				update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+				update_stages_and_entry(ren1_dst,
+							ren1->dst_entry,
+							ren1->pair->one,
+							ren1->pair->two,
+							ren2->pair->two,
+							1 /* clear */);
 			}
 		} else {
 			/* Renamed in 1, maybe changed in 2 */
 			struct string_list_item *item;
 			/* we only use sha1 and mode of these */
 			struct diff_filespec src_other, dst_other;
-			int try_merge, stage = a_renames == renames1 ? 3: 2;
+			int try_merge;
 
-			remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
+			/*
+			 * 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;
 
-			hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
-			src_other.mode = ren1->src_entry->stages[stage].mode;
-			hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
-			dst_other.mode = ren1->dst_entry->stages[stage].mode;
+			remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
 
+			hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
+			src_other.mode = ren1->src_entry->stages[other_stage].mode;
+			hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
+			dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
 			try_merge = 0;
 
-			if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
-				clean_merge = 0;
-				output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
-				       " directory %s added in %s",
-				       ren1_src, ren1_dst, branch1,
-				       ren1_dst, branch2);
-				conflict_rename_dir(o, ren1, branch1);
-			} else if (sha_eq(src_other.sha1, null_sha1)) {
-				clean_merge = 0;
-				output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
-				       "and deleted in %s",
-				       ren1_src, ren1_dst, branch1,
-				       branch2);
-				update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
-				if (!o->call_depth)
-					update_stages(ren1_dst, NULL,
-							branch1 == o->branch1 ?
-							ren1->pair->two : NULL,
-							branch1 == o->branch1 ?
-							NULL : ren1->pair->two, 1);
+			if (sha_eq(src_other.sha1, null_sha1)) {
+				if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
+					ren1->dst_entry->processed = 0;
+					setup_rename_df_conflict_info(RENAME_DELETE,
+								      ren1->pair,
+								      NULL,
+								      branch1,
+								      branch2,
+								      ren1->dst_entry,
+								      NULL);
+				} else {
+					clean_merge = 0;
+					conflict_rename_delete(o, ren1->pair, branch1, branch2);
+				}
+			} else if ((dst_other.mode == ren1->pair->two->mode) &&
+				   sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
+				/* Added file on the other side
+				   identical to the file being
+				   renamed: clean merge */
+				update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 			} else if (!sha_eq(dst_other.sha1, null_sha1)) {
 				const char *new_path;
 				clean_merge = 0;
@@ -983,6 +1098,7 @@ static int process_renames(struct merge_options *o,
 						    mfi.sha,
 						    mfi.mode,
 						    ren1_dst);
+					try_merge = 0;
 				} else {
 					new_path = unique_path(o, ren1_dst, branch2);
 					output(o, 1, "Adding as %s instead", new_path);
@@ -997,13 +1113,12 @@ static int process_renames(struct merge_options *o,
 				       "Rename %s->%s in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren2->pair->one->path, ren2->pair->two->path, branch2);
-				conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
+				conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
 			} else
 				try_merge = 1;
 
 			if (try_merge) {
 				struct diff_filespec *one, *a, *b;
-				struct merge_file_info mfi;
 				src_other.path = (char *)ren1_src;
 
 				one = ren1->pair->one;
@@ -1014,33 +1129,15 @@ static int process_renames(struct merge_options *o,
 					b = ren1->pair->two;
 					a = &src_other;
 				}
-				mfi = merge_file(o, one, a, b,
-						o->branch1, o->branch2);
-
-				if (mfi.clean &&
-				    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
-				    mfi.mode == ren1->pair->two->mode)
-					/*
-					 * This messaged is part of
-					 * t6022 test. If you change
-					 * it update the test too.
-					 */
-					output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
-				else {
-					if (mfi.merge || !mfi.clean)
-						output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
-					if (mfi.merge)
-						output(o, 2, "Auto-merging %s", ren1_dst);
-					if (!mfi.clean) {
-						output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
-						       ren1_dst);
-						clean_merge = 0;
-
-						if (!o->call_depth)
-							update_stages(ren1_dst,
-								      one, a, b, 1);
-					}
-					update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
+				update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
+				if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
+					setup_rename_df_conflict_info(RENAME_NORMAL,
+								      ren1->pair,
+								      NULL,
+								      branch1,
+								      NULL,
+								      ren1->dst_entry,
+								      NULL);
 				}
 			}
 		}
@@ -1056,6 +1153,137 @@ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 	return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 }
 
+static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
+{
+	void *buf;
+	enum object_type type;
+	unsigned long size;
+	buf = read_sha1_file(sha1, &type, &size);
+	if (!buf)
+		return error("cannot read object %s", sha1_to_hex(sha1));
+	if (type != OBJ_BLOB) {
+		free(buf);
+		return error("object %s is not a blob", sha1_to_hex(sha1));
+	}
+	strbuf_attach(dst, buf, size, size + 1);
+	return 0;
+}
+
+static int blob_unchanged(const unsigned char *o_sha,
+			  const unsigned char *a_sha,
+			  int renormalize, const char *path)
+{
+	struct strbuf o = STRBUF_INIT;
+	struct strbuf a = STRBUF_INIT;
+	int ret = 0; /* assume changed for safety */
+
+	if (sha_eq(o_sha, a_sha))
+		return 1;
+	if (!renormalize)
+		return 0;
+
+	assert(o_sha && a_sha);
+	if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
+		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(path, o.buf, o.len, &o) |
+	    renormalize_buffer(path, a.buf, o.len, &a))
+		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+
+error_return:
+	strbuf_release(&o);
+	strbuf_release(&a);
+	return ret;
+}
+
+static void handle_delete_modify(struct merge_options *o,
+				 const char *path,
+				 const char *new_path,
+				 unsigned char *a_sha, int a_mode,
+				 unsigned char *b_sha, int b_mode)
+{
+	if (!a_sha) {
+		output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
+		       "and modified in %s. Version %s of %s left in tree%s%s.",
+		       path, o->branch1,
+		       o->branch2, o->branch2, path,
+		       path == new_path ? "" : " at ",
+		       path == new_path ? "" : new_path);
+		update_file(o, 0, b_sha, b_mode, new_path);
+	} else {
+		output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
+		       "and modified in %s. Version %s of %s left in tree%s%s.",
+		       path, o->branch2,
+		       o->branch1, o->branch1, path,
+		       path == new_path ? "" : " at ",
+		       path == new_path ? "" : new_path);
+		update_file(o, 0, a_sha, a_mode, new_path);
+	}
+}
+
+static int merge_content(struct merge_options *o,
+			 const char *path,
+			 unsigned char *o_sha, int o_mode,
+			 unsigned char *a_sha, int a_mode,
+			 unsigned char *b_sha, int b_mode,
+			 const char *df_rename_conflict_branch)
+{
+	const char *reason = "content";
+	struct merge_file_info mfi;
+	struct diff_filespec one, a, b;
+	struct stat st;
+	unsigned df_conflict_remains = 0;
+
+	if (!o_sha) {
+		reason = "add/add";
+		o_sha = (unsigned char *)null_sha1;
+	}
+	one.path = a.path = b.path = (char *)path;
+	hashcpy(one.sha1, o_sha);
+	one.mode = o_mode;
+	hashcpy(a.sha1, a_sha);
+	a.mode = a_mode;
+	hashcpy(b.sha1, b_sha);
+	b.mode = b_mode;
+
+	mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
+	if (df_rename_conflict_branch &&
+	    lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
+		df_conflict_remains = 1;
+	}
+
+	if (mfi.clean && !df_conflict_remains &&
+	    sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
+		output(o, 3, "Skipped %s (merged same as existing)", path);
+	else
+		output(o, 2, "Auto-merging %s", path);
+
+	if (!mfi.clean) {
+		if (S_ISGITLINK(mfi.mode))
+			reason = "submodule";
+		output(o, 1, "CONFLICT (%s): Merge conflict in %s",
+				reason, path);
+	}
+
+	if (df_conflict_remains) {
+		const char *new_path;
+		update_file_flags(o, mfi.sha, mfi.mode, path,
+				  o->call_depth || mfi.clean, 0);
+		new_path = unique_path(o, path, df_rename_conflict_branch);
+		mfi.clean = 0;
+		output(o, 1, "Adding as %s instead", new_path);
+		update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
+	} else {
+		update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
+	}
+	return mfi.clean;
+
+}
+
 /* Per entry merge function */
 static int process_entry(struct merge_options *o,
 			 const char *path, struct stage_data *entry)
@@ -1065,6 +1293,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
+	int normalize = o->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1072,65 +1301,49 @@ static int process_entry(struct merge_options *o,
 	unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
 	unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
 
+	if (entry->rename_df_conflict_info)
+		return 1; /* Such cases are handled elsewhere. */
+
+	entry->processed = 1;
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
 		if ((!a_sha && !b_sha) ||
-		    (sha_eq(a_sha, o_sha) && !b_sha) ||
-		    (!a_sha && sha_eq(b_sha, o_sha))) {
+		    (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
+		    (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
 				output(o, 2, "Removing %s", path);
 			/* do not touch working file if it did not exist */
 			remove_file(o, 1, path, !a_sha);
+		} else if (string_list_has_string(&o->current_directory_set,
+						  path)) {
+			entry->processed = 0;
+			return 1; /* Assume clean until processed */
 		} else {
 			/* Deleted in one and changed in the other */
 			clean_merge = 0;
-			if (!a_sha) {
-				output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
-				       "and modified in %s. Version %s of %s left in tree.",
-				       path, o->branch1,
-				       o->branch2, o->branch2, path);
-				update_file(o, 0, b_sha, b_mode, path);
-			} else {
-				output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
-				       "and modified in %s. Version %s of %s left in tree.",
-				       path, o->branch2,
-				       o->branch1, o->branch1, path);
-				update_file(o, 0, a_sha, a_mode, path);
-			}
+			handle_delete_modify(o, path, path,
+					     a_sha, a_mode, b_sha, b_mode);
 		}
 
 	} else if ((!o_sha && a_sha && !b_sha) ||
 		   (!o_sha && !a_sha && b_sha)) {
 		/* Case B: Added in one. */
-		const char *add_branch;
-		const char *other_branch;
 		unsigned mode;
 		const unsigned char *sha;
-		const char *conf;
 
 		if (a_sha) {
-			add_branch = o->branch1;
-			other_branch = o->branch2;
 			mode = a_mode;
 			sha = a_sha;
-			conf = "file/directory";
 		} else {
-			add_branch = o->branch2;
-			other_branch = o->branch1;
 			mode = b_mode;
 			sha = b_sha;
-			conf = "directory/file";
 		}
 		if (string_list_has_string(&o->current_directory_set, path)) {
-			const char *new_path = unique_path(o, path, add_branch);
-			clean_merge = 0;
-			output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
-			       "Adding %s as %s",
-			       conf, path, other_branch, path, new_path);
-			remove_file(o, 0, path, 0);
-			update_file(o, 0, sha, mode, new_path);
+			/* Handle D->F conflicts after all subfiles */
+			entry->processed = 0;
+			return 1; /* Assume clean until processed */
 		} else {
 			output(o, 2, "Adding %s", path);
 			update_file(o, 1, sha, mode, path);
@@ -1138,34 +1351,9 @@ static int process_entry(struct merge_options *o,
 	} else if (a_sha && b_sha) {
 		/* Case C: Added in both (check for same permissions) and */
 		/* case D: Modified in both, but differently. */
-		const char *reason = "content";
-		struct merge_file_info mfi;
-		struct diff_filespec one, a, b;
-
-		if (!o_sha) {
-			reason = "add/add";
-			o_sha = (unsigned char *)null_sha1;
-		}
-		output(o, 2, "Auto-merging %s", path);
-		one.path = a.path = b.path = (char *)path;
-		hashcpy(one.sha1, o_sha);
-		one.mode = o_mode;
-		hashcpy(a.sha1, a_sha);
-		a.mode = a_mode;
-		hashcpy(b.sha1, b_sha);
-		b.mode = b_mode;
-
-		mfi = merge_file(o, &one, &a, &b,
-				 o->branch1, o->branch2);
-
-		clean_merge = mfi.clean;
-		if (!mfi.clean) {
-			if (S_ISGITLINK(mfi.mode))
-				reason = "submodule";
-			output(o, 1, "CONFLICT (%s): Merge conflict in %s",
-					reason, path);
-		}
-		update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
+		clean_merge = merge_content(o, path,
+					    o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
+					    NULL);
 	} else if (!o_sha && !a_sha && !b_sha) {
 		/*
 		 * this entry was deleted altogether. a_mode == 0 means
@@ -1178,26 +1366,116 @@ static int process_entry(struct merge_options *o,
 	return clean_merge;
 }
 
-struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
+/*
+ * Per entry merge function for D/F (and/or rename) conflicts.  In the
+ * cases we can cleanly resolve D/F conflicts, process_entry() can
+ * clean out all the files below the directory for us.  All D/F
+ * conflict cases must be handled here at the end to make sure any
+ * directories that can be cleaned out, are.
+ *
+ * Some rename conflicts may also be handled here that don't necessarily
+ * involve D/F conflicts, since the code to handle them is generic enough
+ * to handle those rename conflicts with or without D/F conflicts also
+ * being involved.
+ */
+static int process_df_entry(struct merge_options *o,
+			    const char *path, struct stage_data *entry)
 {
-	struct unpack_trees_error_msgs msgs = {
-		/* would_overwrite */
-		"Your local changes to '%s' would be overwritten by merge.  Aborting.",
-		/* not_uptodate_file */
-		"Your local changes to '%s' would be overwritten by merge.  Aborting.",
-		/* not_uptodate_dir */
-		"Updating '%s' would lose untracked files in it.  Aborting.",
-		/* would_lose_untracked */
-		"Untracked working tree file '%s' would be %s by merge.  Aborting",
-		/* bind_overlap -- will not happen here */
-		NULL,
-	};
-	if (advice_commit_before_merge) {
-		msgs.would_overwrite = msgs.not_uptodate_file =
-			"Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
-			"Please, commit your changes or stash them before you can merge.";
+	int clean_merge = 1;
+	unsigned o_mode = entry->stages[1].mode;
+	unsigned a_mode = entry->stages[2].mode;
+	unsigned b_mode = entry->stages[3].mode;
+	unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
+	unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
+	unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
+	struct stat st;
+
+	entry->processed = 1;
+	if (entry->rename_df_conflict_info) {
+		struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
+		char *src;
+		switch (conflict_info->rename_type) {
+		case RENAME_NORMAL:
+			clean_merge = merge_content(o, path,
+						    o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
+						    conflict_info->branch1);
+			break;
+		case RENAME_DELETE:
+			clean_merge = 0;
+			conflict_rename_delete(o, conflict_info->pair1,
+					       conflict_info->branch1,
+					       conflict_info->branch2);
+			break;
+		case RENAME_ONE_FILE_TO_TWO:
+			src = conflict_info->pair1->one->path;
+			clean_merge = 0;
+			output(o, 1, "CONFLICT (rename/rename): "
+			       "Rename \"%s\"->\"%s\" in branch \"%s\" "
+			       "rename \"%s\"->\"%s\" in \"%s\"%s",
+			       src, conflict_info->pair1->two->path, conflict_info->branch1,
+			       src, conflict_info->pair2->two->path, conflict_info->branch2,
+			       o->call_depth ? " (left unresolved)" : "");
+			if (o->call_depth) {
+				remove_file_from_cache(src);
+				update_file(o, 0, conflict_info->pair1->one->sha1,
+					    conflict_info->pair1->one->mode, src);
+			}
+			conflict_rename_rename_1to2(o, conflict_info->pair1,
+						    conflict_info->branch1,
+						    conflict_info->pair2,
+						    conflict_info->branch2);
+			conflict_info->dst_entry2->processed = 1;
+			break;
+		default:
+			entry->processed = 0;
+			break;
+		}
+	} else if (o_sha && (!a_sha || !b_sha)) {
+		/* Modify/delete; deleted side may have put a directory in the way */
+		const char *new_path = path;
+		if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode))
+			new_path = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
+		clean_merge = 0;
+		handle_delete_modify(o, path, new_path,
+				     a_sha, a_mode, b_sha, b_mode);
+	} else if (!o_sha && !!a_sha != !!b_sha) {
+		/* directory -> (directory, file) */
+		const char *add_branch;
+		const char *other_branch;
+		unsigned mode;
+		const unsigned char *sha;
+		const char *conf;
+
+		if (a_sha) {
+			add_branch = o->branch1;
+			other_branch = o->branch2;
+			mode = a_mode;
+			sha = a_sha;
+			conf = "file/directory";
+		} else {
+			add_branch = o->branch2;
+			other_branch = o->branch1;
+			mode = b_mode;
+			sha = b_sha;
+			conf = "directory/file";
+		}
+		if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
+			const char *new_path = unique_path(o, path, add_branch);
+			clean_merge = 0;
+			output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
+			       "Adding %s as %s",
+			       conf, path, other_branch, path, new_path);
+			update_file(o, 0, sha, mode, new_path);
+		} else {
+			output(o, 2, "Adding %s", path);
+			update_file(o, 1, sha, mode, path);
+		}
+	} else {
+		entry->processed = 0;
+		return 1; /* not handled; assume clean until processed */
 	}
-	return msgs;
+
+	return clean_merge;
 }
 
 int merge_trees(struct merge_options *o,
@@ -1214,7 +1492,7 @@ int merge_trees(struct merge_options *o,
 	}
 
 	if (sha_eq(common->object.sha1, merge->object.sha1)) {
-		output(o, 0, "Already uptodate!");
+		output(o, 0, "Already up-to-date!");
 		*result = head;
 		return 1;
 	}
@@ -1239,6 +1517,7 @@ int merge_trees(struct merge_options *o,
 		get_files_dirs(o, merge);
 
 		entries = get_unmerged();
+		make_room_for_directories_of_df_conflicts(o, entries);
 		re_head  = get_renames(o, head, common, head, merge, entries);
 		re_merge = get_renames(o, merge, common, head, merge, entries);
 		clean = process_renames(o, re_head, re_merge);
@@ -1249,6 +1528,19 @@ int merge_trees(struct merge_options *o,
 				&& !process_entry(o, path, e))
 				clean = 0;
 		}
+		for (i = 0; i < entries->nr; i++) {
+			const char *path = entries->items[i].string;
+			struct stage_data *e = entries->items[i].util;
+			if (!e->processed
+				&& !process_df_entry(o, path, e))
+				clean = 0;
+		}
+		for (i = 0; i < entries->nr; i++) {
+			struct stage_data *e = entries->items[i].util;
+			if (!e->processed)
+				die("Unprocessed path??? %s",
+				    entries->items[i].string);
+		}
 
 		string_list_clear(re_merge, 0);
 		string_list_clear(re_head, 0);
@@ -1357,6 +1649,9 @@ int merge_recursive(struct merge_options *o,
 		commit_list_insert(h2, &(*result)->parents->next);
 	}
 	flush_output(o);
+	if (show(o, 2))
+		diff_warn_rename_limit("merge.renamelimit",
+				       o->needed_rename_limit, 0);
 	return clean;
 }
 
@@ -1414,15 +1709,15 @@ int merge_recursive_generic(struct merge_options *o,
 static int merge_recursive_config(const char *var, const char *value, void *cb)
 {
 	struct merge_options *o = cb;
-	if (!strcasecmp(var, "merge.verbosity")) {
+	if (!strcmp(var, "merge.verbosity")) {
 		o->verbosity = git_config_int(var, value);
 		return 0;
 	}
-	if (!strcasecmp(var, "diff.renamelimit")) {
+	if (!strcmp(var, "diff.renamelimit")) {
 		o->diff_rename_limit = git_config_int(var, value);
 		return 0;
 	}
-	if (!strcasecmp(var, "merge.renamelimit")) {
+	if (!strcmp(var, "merge.renamelimit")) {
 		o->merge_rename_limit = git_config_int(var, value);
 		return 0;
 	}
@@ -1436,6 +1731,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
+	o->renormalize = 0;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =
@@ -1448,3 +1744,37 @@ void init_merge_options(struct merge_options *o)
 	memset(&o->current_directory_set, 0, sizeof(struct string_list));
 	o->current_directory_set.strdup_strings = 1;
 }
+
+int parse_merge_opt(struct merge_options *o, const char *s)
+{
+	if (!s || !*s)
+		return -1;
+	if (!strcmp(s, "ours"))
+		o->recursive_variant = MERGE_RECURSIVE_OURS;
+	else if (!strcmp(s, "theirs"))
+		o->recursive_variant = MERGE_RECURSIVE_THEIRS;
+	else if (!strcmp(s, "subtree"))
+		o->subtree_shift = "";
+	else if (!prefixcmp(s, "subtree="))
+		o->subtree_shift = s + strlen("subtree=");
+	else if (!strcmp(s, "patience"))
+		o->xdl_opts |= XDF_PATIENCE_DIFF;
+	else if (!strcmp(s, "ignore-space-change"))
+		o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
+	else if (!strcmp(s, "ignore-all-space"))
+		o->xdl_opts |= XDF_IGNORE_WHITESPACE;
+	else if (!strcmp(s, "ignore-space-at-eol"))
+		o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
+	else if (!strcmp(s, "renormalize"))
+		o->renormalize = 1;
+	else if (!strcmp(s, "no-renormalize"))
+		o->renormalize = 0;
+	else if (!prefixcmp(s, "rename-threshold=")) {
+		const char *score = s + strlen("rename-threshold=");
+		if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
+			return -1;
+	}
+	else
+		return -1;
+	return 0;
+}