Merge branch 'nd/index-doc'
[gitweb.git] / merge-recursive.c
index 206c1036359ce7b1fc5a1f5734b2d0bc2a760d90..8e82a8b1a5ab8a2f5af00910a8febda93b9e420d 100644 (file)
 #include "attr.h"
 #include "merge-recursive.h"
 #include "dir.h"
+#include "submodule.h"
+
+static const char rename_limit_advice[] =
+"inexact rename detection was skipped because there were too many\n"
+"  files. You may want to set your merge.renamelimit variable to at least\n"
+"  %d and retry this merge.";
 
 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
                                      const char *subtree_shift)
@@ -62,20 +68,62 @@ 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 +140,6 @@ 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 +150,9 @@ 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 +171,10 @@ 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 +214,7 @@ 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);
@@ -238,9 +267,9 @@ static int save_files_dirs(const unsigned char *sha1,
        newpath[baselen + len] = '\0';
 
        if (S_ISDIR(mode))
-               string_list_insert(newpath, &o->current_directory_set);
+               string_list_insert(&o->current_directory_set, newpath);
        else
-               string_list_insert(newpath, &o->current_file_set);
+               string_list_insert(&o->current_file_set, newpath);
        free(newpath);
 
        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
@@ -271,7 +300,7 @@ static struct stage_data *insert_stage_data(const char *path,
                        e->stages[2].sha, &e->stages[2].mode);
        get_tree_entry(b->object.sha1, path,
                        e->stages[3].sha, &e->stages[3].mode);
-       item = string_list_insert(path, entries);
+       item = string_list_insert(entries, path);
        item->util = e;
        return e;
 }
@@ -294,9 +323,9 @@ static struct string_list *get_unmerged(void)
                if (!ce_stage(ce))
                        continue;
 
-               item = string_list_lookup(ce->name, unmerged);
+               item = string_list_lookup(unmerged, ce->name);
                if (!item) {
-                       item = string_list_insert(ce->name, unmerged);
+                       item = string_list_insert(unmerged, ce->name);
                        item->util = xcalloc(1, sizeof(struct stage_data));
                }
                e = item->util;
@@ -307,8 +336,64 @@ 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;
+       struct stage_data *last_e;
+       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;
+                       last_e = e;
+               } else {
+                       last_file = NULL;
+               }
+       }
+}
+
+struct rename {
        struct diff_filepair *pair;
        struct stage_data *src_entry;
        struct stage_data *dst_entry;
@@ -338,13 +423,16 @@ 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;
@@ -356,20 +444,20 @@ static struct string_list *get_renames(struct merge_options *o,
                re = xmalloc(sizeof(*re));
                re->processed = 0;
                re->pair = pair;
-               item = string_list_lookup(re->pair->one->path, entries);
+               item = string_list_lookup(entries, re->pair->one->path);
                if (!item)
                        re->src_entry = insert_stage_data(re->pair->one->path,
                                        o_tree, a_tree, b_tree, entries);
                else
                        re->src_entry = item->util;
 
-               item = string_list_lookup(re->pair->two->path, entries);
+               item = string_list_lookup(entries, re->pair->two->path);
                if (!item)
                        re->dst_entry = insert_stage_data(re->pair->two->path,
                                        o_tree, a_tree, b_tree, entries);
                else
                        re->dst_entry = item->util;
-               item = string_list_insert(pair->one->path, renames);
+               item = string_list_insert(renames, pair->one->path);
                item->util = re;
        }
        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
@@ -378,11 +466,10 @@ 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 +485,34 @@ 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)
 {
@@ -432,7 +547,7 @@ static char *unique_path(struct merge_options *o, const char *path, const char *
               lstat(newpath, &st) == 0)
                sprintf(p, "_%d", suffix++);
 
-       string_list_insert(newpath, &o->current_file_set);
+       string_list_insert(&o->current_file_set, newpath);
        return newpath;
 }
 
@@ -525,13 +640,15 @@ 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 +708,7 @@ 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 +724,26 @@ 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 +766,7 @@ 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 +835,8 @@ 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 +850,56 @@ 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 +907,27 @@ 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",
@@ -806,17 +945,18 @@ 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++) {
                sre = a_renames->items[i].util;
-               string_list_insert(sre->pair->two->path, &a_by_dst)->util
+               string_list_insert(&a_by_dst, sre->pair->two->path)->util
                        = sre->dst_entry;
        }
        for (i = 0; i < b_renames->nr; i++) {
                sre = b_renames->items[i].util;
-               string_list_insert(sre->pair->two->path, &b_by_dst)->util
+               string_list_insert(&b_by_dst, sre->pair->two->path)->util
                        = sre->dst_entry;
        }
 
@@ -877,84 +1017,66 @@ 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;
@@ -983,12 +1105,13 @@ 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);
                                        update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
                                }
-                       } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
+                       } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
                                ren2 = item->util;
                                clean_merge = 0;
                                ren2->processed = 1;
@@ -997,13 +1120,12 @@ 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 +1136,15 @@ 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 +1160,137 @@ 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 +1300,7 @@ 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 +1308,49 @@ 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 +1358,9 @@ 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 +1373,116 @@ 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 +1499,7 @@ 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 +1524,7 @@ 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 +1535,19 @@ 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 +1656,8 @@ int merge_recursive(struct merge_options *o,
                commit_list_insert(h2, &(*result)->parents->next);
        }
        flush_output(o);
+       if (o->needed_rename_limit)
+               warning(rename_limit_advice, o->needed_rename_limit);
        return clean;
 }
 
@@ -1436,6 +1737,7 @@ 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 +1750,37 @@ 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;
+}