Merge branch 'sb/object-store-grafts'
[gitweb.git] / merge-recursive.c
index 16d2377b71bf40ae88fa5ffd5863105a40e6c96b..113c1d69625935a2f3c476af0ec0ca92201417e7 100644 (file)
@@ -8,6 +8,7 @@
 #include "advice.h"
 #include "lockfile.h"
 #include "cache-tree.h"
+#include "object-store.h"
 #include "commit.h"
 #include "blob.h"
 #include "builtin.h"
@@ -15,6 +16,7 @@
 #include "diff.h"
 #include "diffcore.h"
 #include "tag.h"
+#include "alloc.h"
 #include "unpack-trees.h"
 #include "string-list.h"
 #include "xdiff-interface.h"
@@ -23,6 +25,7 @@
 #include "merge-recursive.h"
 #include "dir.h"
 #include "submodule.h"
+#include "revision.h"
 
 struct path_hashmap_entry {
        struct hashmap_entry e;
@@ -159,10 +162,10 @@ static struct tree *shift_tree_object(struct tree *one, struct tree *two,
 
 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 {
-       struct commit *commit = alloc_commit_node();
+       struct commit *commit = alloc_commit_node(the_repository);
 
        set_merge_remote_desc(commit, comment, (struct object *)commit);
-       commit->tree = tree;
+       commit->maybe_tree = tree;
        commit->object.parsed = 1;
        return commit;
 }
@@ -180,7 +183,7 @@ static int oid_eq(const struct object_id *a, const struct object_id *b)
 
 enum rename_type {
        RENAME_NORMAL = 0,
-       RENAME_DIR,
+       RENAME_VIA_DIR,
        RENAME_DELETE,
        RENAME_ONE_FILE_TO_ONE,
        RENAME_ONE_FILE_TO_TWO,
@@ -285,10 +288,12 @@ static void output(struct merge_options *o, int v, const char *fmt, ...)
 
 static void output_commit_title(struct merge_options *o, struct commit *commit)
 {
+       struct merge_remote_desc *desc;
+
        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
-       if (commit->util)
-               strbuf_addf(&o->obuf, "virtual %s\n",
-                       merge_remote_util(commit)->name);
+       desc = merge_remote_util(commit);
+       if (desc)
+               strbuf_addf(&o->obuf, "virtual %s\n", desc->name);
        else {
                strbuf_add_unique_abbrev(&o->obuf, &commit->object.oid,
                                         DEFAULT_ABBREV);
@@ -308,8 +313,8 @@ static void output_commit_title(struct merge_options *o, struct commit *commit)
 }
 
 static int add_cacheinfo(struct merge_options *o,
-               unsigned int mode, const struct object_id *oid,
-               const char *path, int stage, int refresh, int options)
+                        unsigned int mode, const struct object_id *oid,
+                        const char *path, int stage, int refresh, int options)
 {
        struct cache_entry *ce;
        int ret;
@@ -337,10 +342,10 @@ static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
        init_tree_desc(desc, tree->buffer, tree->size);
 }
 
-static int git_merge_trees(struct merge_options *o,
-                          struct tree *common,
-                          struct tree *head,
-                          struct tree *merge)
+static int unpack_trees_start(struct merge_options *o,
+                             struct tree *common,
+                             struct tree *head,
+                             struct tree *merge)
 {
        int rc;
        struct tree_desc t[3];
@@ -356,6 +361,7 @@ static int git_merge_trees(struct merge_options *o,
        o->unpack_opts.fn = threeway_merge;
        o->unpack_opts.src_index = &the_index;
        o->unpack_opts.dst_index = &tmp_index;
+       o->unpack_opts.aggressive = !merge_detect_rename(o);
        setup_unpack_trees_porcelain(&o->unpack_opts, "merge");
 
        init_tree_desc_from_tree(t+0, common);
@@ -378,6 +384,12 @@ static int git_merge_trees(struct merge_options *o,
        return rc;
 }
 
+static void unpack_trees_finish(struct merge_options *o)
+{
+       discard_index(&o->orig_index);
+       clear_unpack_trees_porcelain(&o->unpack_opts);
+}
+
 struct tree *write_tree_from_memory(struct merge_options *o)
 {
        struct tree *result = NULL;
@@ -391,7 +403,7 @@ struct tree *write_tree_from_memory(struct merge_options *o)
                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
                                        (int)ce_namelen(ce), ce->name);
                }
-               die("BUG: unmerged index entries in merge-recursive.c");
+               BUG("unmerged index entries in merge-recursive.c");
        }
 
        if (!active_cache_tree)
@@ -409,8 +421,8 @@ struct tree *write_tree_from_memory(struct merge_options *o)
 }
 
 static int save_files_dirs(const struct object_id *oid,
-               struct strbuf *base, const char *path,
-               unsigned int mode, int stage, void *context)
+                          struct strbuf *base, const char *path,
+                          unsigned int mode, int stage, void *context)
 {
        struct path_hashmap_entry *entry;
        int baselen = base->len;
@@ -531,7 +543,7 @@ static void record_df_conflict_files(struct merge_options *o,
                                     struct string_list *entries)
 {
        /* If there is a D/F conflict and the file for such a conflict
-        * currently exist in the working tree, we want to allow it to be
+        * currently exists in the working tree, we want to allow it to be
         * removed to make room for the corresponding directory if needed.
         * The files underneath the directories of such D/F conflicts will
         * be processed before the corresponding file involved in the D/F
@@ -905,7 +917,7 @@ static int make_room_for_path(struct merge_options *o, const char *path)
         */
        if (would_lose_untracked(path))
                return err(o, _("refusing to lose untracked file at '%s'"),
-                            path);
+                          path);
 
        /* Successful unlink is good.. */
        if (!unlink(path))
@@ -984,16 +996,16 @@ static int update_file_flags(struct merge_options *o,
                        unlink(path);
                        if (symlink(lnk, path))
                                ret = err(o, _("failed to symlink '%s': %s"),
-                                       path, strerror(errno));
+                                         path, strerror(errno));
                        free(lnk);
                } else
                        ret = err(o,
                                  _("do not know what to do with %06o %s '%s'"),
                                  mode, oid_to_hex(oid), path);
- free_buf:
      free_buf:
                free(buf);
        }
- update_index:
+update_index:
        if (!ret && update_cache)
                if (add_cacheinfo(o, mode, oid, path, 0, update_wd,
                                  ADD_CACHE_OK_TO_ADD))
@@ -1081,6 +1093,185 @@ static int merge_3way(struct merge_options *o,
        return merge_status;
 }
 
+static int find_first_merges(struct object_array *result, const char *path,
+                            struct commit *a, struct commit *b)
+{
+       int i, j;
+       struct object_array merges = OBJECT_ARRAY_INIT;
+       struct commit *commit;
+       int contains_another;
+
+       char merged_revision[42];
+       const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
+                                  "--all", merged_revision, NULL };
+       struct rev_info revs;
+       struct setup_revision_opt rev_opts;
+
+       memset(result, 0, sizeof(struct object_array));
+       memset(&rev_opts, 0, sizeof(rev_opts));
+
+       /* get all revisions that merge commit a */
+       xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
+                 oid_to_hex(&a->object.oid));
+       init_revisions(&revs, NULL);
+       rev_opts.submodule = path;
+       /* FIXME: can't handle linked worktrees in submodules yet */
+       revs.single_worktree = path != NULL;
+       setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
+
+       /* save all revisions from the above list that contain b */
+       if (prepare_revision_walk(&revs))
+               die("revision walk setup failed");
+       while ((commit = get_revision(&revs)) != NULL) {
+               struct object *o = &(commit->object);
+               if (in_merge_bases(b, commit))
+                       add_object_array(o, NULL, &merges);
+       }
+       reset_revision_walk();
+
+       /* Now we've got all merges that contain a and b. Prune all
+        * merges that contain another found merge and save them in
+        * result.
+        */
+       for (i = 0; i < merges.nr; i++) {
+               struct commit *m1 = (struct commit *) merges.objects[i].item;
+
+               contains_another = 0;
+               for (j = 0; j < merges.nr; j++) {
+                       struct commit *m2 = (struct commit *) merges.objects[j].item;
+                       if (i != j && in_merge_bases(m2, m1)) {
+                               contains_another = 1;
+                               break;
+                       }
+               }
+
+               if (!contains_another)
+                       add_object_array(merges.objects[i].item, NULL, result);
+       }
+
+       object_array_clear(&merges);
+       return result->nr;
+}
+
+static void print_commit(struct commit *commit)
+{
+       struct strbuf sb = STRBUF_INIT;
+       struct pretty_print_context ctx = {0};
+       ctx.date_mode.type = DATE_NORMAL;
+       format_commit_message(commit, " %h: %m %s", &sb, &ctx);
+       fprintf(stderr, "%s\n", sb.buf);
+       strbuf_release(&sb);
+}
+
+static int merge_submodule(struct merge_options *o,
+                          struct object_id *result, const char *path,
+                          const struct object_id *base, const struct object_id *a,
+                          const struct object_id *b)
+{
+       struct commit *commit_base, *commit_a, *commit_b;
+       int parent_count;
+       struct object_array merges;
+
+       int i;
+       int search = !o->call_depth;
+
+       /* store a in result in case we fail */
+       oidcpy(result, a);
+
+       /* we can not handle deletion conflicts */
+       if (is_null_oid(base))
+               return 0;
+       if (is_null_oid(a))
+               return 0;
+       if (is_null_oid(b))
+               return 0;
+
+       if (add_submodule_odb(path)) {
+               output(o, 1, _("Failed to merge submodule %s (not checked out)"), path);
+               return 0;
+       }
+
+       if (!(commit_base = lookup_commit_reference(base)) ||
+           !(commit_a = lookup_commit_reference(a)) ||
+           !(commit_b = lookup_commit_reference(b))) {
+               output(o, 1, _("Failed to merge submodule %s (commits not present)"), path);
+               return 0;
+       }
+
+       /* check whether both changes are forward */
+       if (!in_merge_bases(commit_base, commit_a) ||
+           !in_merge_bases(commit_base, commit_b)) {
+               output(o, 1, _("Failed to merge submodule %s (commits don't follow merge-base)"), path);
+               return 0;
+       }
+
+       /* Case #1: a is contained in b or vice versa */
+       if (in_merge_bases(commit_a, commit_b)) {
+               oidcpy(result, b);
+               if (show(o, 3)) {
+                       output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+                       output_commit_title(o, commit_b);
+               } else if (show(o, 2))
+                       output(o, 2, _("Fast-forwarding submodule %s"), path);
+               else
+                       ; /* no output */
+
+               return 1;
+       }
+       if (in_merge_bases(commit_b, commit_a)) {
+               oidcpy(result, a);
+               if (show(o, 3)) {
+                       output(o, 3, _("Fast-forwarding submodule %s to the following commit:"), path);
+                       output_commit_title(o, commit_a);
+               } else if (show(o, 2))
+                       output(o, 2, _("Fast-forwarding submodule %s"), path);
+               else
+                       ; /* no output */
+
+               return 1;
+       }
+
+       /*
+        * Case #2: There are one or more merges that contain a and b in
+        * the submodule. If there is only one, then present it as a
+        * suggestion to the user, but leave it marked unmerged so the
+        * user needs to confirm the resolution.
+        */
+
+       /* Skip the search if makes no sense to the calling context.  */
+       if (!search)
+               return 0;
+
+       /* find commit which merges them */
+       parent_count = find_first_merges(&merges, path, commit_a, commit_b);
+       switch (parent_count) {
+       case 0:
+               output(o, 1, _("Failed to merge submodule %s (merge following commits not found)"), path);
+               break;
+
+       case 1:
+               output(o, 1, _("Failed to merge submodule %s (not fast-forward)"), path);
+               output(o, 2, _("Found a possible merge resolution for the submodule:\n"));
+               print_commit((struct commit *) merges.objects[0].item);
+               output(o, 2, _(
+                      "If this is correct simply add it to the index "
+                      "for example\n"
+                      "by using:\n\n"
+                      "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
+                      "which will accept this suggestion.\n"),
+                      oid_to_hex(&merges.objects[0].item->oid), path);
+               break;
+
+       default:
+               output(o, 1, _("Failed to merge submodule %s (multiple merges found)"), path);
+               for (i = 0; i < merges.nr; i++)
+                       print_commit((struct commit *) merges.objects[i].item);
+       }
+
+       object_array_clear(&merges);
+       return 0;
+}
+
 static int merge_file_1(struct merge_options *o,
                        const struct diff_filespec *one,
                        const struct diff_filespec *a,
@@ -1144,12 +1335,11 @@ static int merge_file_1(struct merge_options *o,
                                return ret;
                        result->clean = (merge_status == 0);
                } else if (S_ISGITLINK(a->mode)) {
-                       result->clean = merge_submodule(&result->oid,
-                                                      one->path,
-                                                      &one->oid,
-                                                      &a->oid,
-                                                      &b->oid,
-                                                      !o->call_depth);
+                       result->clean = merge_submodule(o, &result->oid,
+                                                       one->path,
+                                                       &one->oid,
+                                                       &a->oid,
+                                                       &b->oid);
                } else if (S_ISLNK(a->mode)) {
                        switch (o->recursive_variant) {
                        case MERGE_RECURSIVE_NORMAL:
@@ -1165,7 +1355,7 @@ static int merge_file_1(struct merge_options *o,
                                break;
                        }
                } else
-                       die("BUG: unsupported object type in the tree");
+                       BUG("unsupported object type in the tree");
        }
 
        if (result->merge)
@@ -1224,11 +1414,17 @@ static int merge_file_one(struct merge_options *o,
        return merge_file_1(o, &one, &a, &b, path, branch1, branch2, mfi);
 }
 
-static int conflict_rename_dir(struct merge_options *o,
-                              struct diff_filepair *pair,
-                              const char *rename_branch,
-                              const char *other_branch)
+static int handle_rename_via_dir(struct merge_options *o,
+                                struct diff_filepair *pair,
+                                const char *rename_branch,
+                                const char *other_branch)
 {
+       /*
+        * Handle file adds that need to be renamed due to directory rename
+        * detection.  This differs from handle_rename_normal, because
+        * there is no content merge to do; just move the file into the
+        * desired final location.
+        */
        const struct diff_filespec *dest = pair->two;
 
        if (!o->call_depth && would_lose_untracked(dest->path)) {
@@ -1257,13 +1453,13 @@ static int conflict_rename_dir(struct merge_options *o,
 }
 
 static int handle_change_delete(struct merge_options *o,
-                                const char *path, const char *old_path,
-                                const struct object_id *o_oid, int o_mode,
-                                const struct object_id *changed_oid,
-                                int changed_mode,
-                                const char *change_branch,
-                                const char *delete_branch,
-                                const char *change, const char *change_past)
+                               const char *path, const char *old_path,
+                               const struct object_id *o_oid, int o_mode,
+                               const struct object_id *changed_oid,
+                               int changed_mode,
+                               const char *change_branch,
+                               const char *delete_branch,
+                               const char *change, const char *change_past)
 {
        char *alt_path = NULL;
        const char *update_path = path;
@@ -1284,6 +1480,21 @@ static int handle_change_delete(struct merge_options *o,
                if (!ret)
                        ret = update_file(o, 0, o_oid, o_mode, update_path);
        } else {
+               /*
+                * Despite the four nearly duplicate messages and argument
+                * lists below and the ugliness of the nested if-statements,
+                * having complete messages makes the job easier for
+                * translators.
+                *
+                * The slight variance among the cases is due to the fact
+                * that:
+                *   1) directory/file conflicts (in effect if
+                *      !alt_path) could cause us to need to write the
+                *      file to a different path.
+                *   2) renames (in effect if !old_path) could mean that
+                *      there are two names for the path that the user
+                *      may know the file by.
+                */
                if (!alt_path) {
                        if (!old_path) {
                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
@@ -1323,10 +1534,10 @@ static int handle_change_delete(struct merge_options *o,
        return ret;
 }
 
-static int conflict_rename_delete(struct merge_options *o,
-                                  struct diff_filepair *pair,
-                                  const char *rename_branch,
-                                  const char *delete_branch)
+static int handle_rename_delete(struct merge_options *o,
+                               struct diff_filepair *pair,
+                               const char *rename_branch,
+                               const char *delete_branch)
 {
        const struct diff_filespec *orig = pair->one;
        const struct diff_filespec *dest = pair->two;
@@ -1428,8 +1639,8 @@ static int handle_file(struct merge_options *o,
        return ret;
 }
 
-static int conflict_rename_rename_1to2(struct merge_options *o,
-                                       struct rename_conflict_info *ci)
+static int handle_rename_rename_1to2(struct merge_options *o,
+                                    struct rename_conflict_info *ci)
 {
        /* One file was renamed in both branches, but to different names. */
        struct diff_filespec *one = ci->pair1->one;
@@ -1490,8 +1701,8 @@ static int conflict_rename_rename_1to2(struct merge_options *o,
        return 0;
 }
 
-static int conflict_rename_rename_2to1(struct merge_options *o,
-                                       struct rename_conflict_info *ci)
+static int handle_rename_rename_2to1(struct merge_options *o,
+                                    struct rename_conflict_info *ci)
 {
        /* Two files, a & b, were renamed to the same thing, c. */
        struct diff_filespec *a = ci->pair1->one;
@@ -1603,7 +1814,15 @@ static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
        diff_setup(&opts);
        opts.flags.recursive = 1;
        opts.flags.rename_empty = 0;
-       opts.detect_rename = DIFF_DETECT_RENAME;
+       opts.detect_rename = merge_detect_rename(o);
+       /*
+        * We do not have logic to handle the detection of copies.  In
+        * fact, it may not even make sense to add such logic: would we
+        * really want a change to a base file to be propagated through
+        * multiple other files by a merge?
+        */
+       if (opts.detect_rename > DIFF_DETECT_RENAME)
+               opts.detect_rename = DIFF_DETECT_RENAME;
        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
                            1000;
@@ -2225,7 +2444,7 @@ static void apply_directory_rename_modifications(struct merge_options *o,
         * "NOTE" in update_stages(), doing so will modify the current
         * in-memory index which will break calls to would_lose_untracked()
         * that we need to make.  Instead, we need to just make sure that
-        * the various conflict_rename_*() functions update the index
+        * the various handle_rename_*() functions update the index
         * explicitly rather than relying on unpack_trees() to have done it.
         */
        get_tree_entry(&tree->object.oid,
@@ -2410,7 +2629,7 @@ static int process_renames(struct merge_options *o,
                        const char *ren2_dst = ren2->pair->two->path;
                        enum rename_type rename_type;
                        if (strcmp(ren1_src, ren2_src) != 0)
-                               die("BUG: ren1_src != ren2_src");
+                               BUG("ren1_src != ren2_src");
                        ren2->dst_entry->processed = 1;
                        ren2->processed = 1;
                        if (strcmp(ren1_dst, ren2_dst) != 0) {
@@ -2444,7 +2663,7 @@ static int process_renames(struct merge_options *o,
                        ren2 = lookup->util;
                        ren2_dst = ren2->pair->two->path;
                        if (strcmp(ren1_dst, ren2_dst) != 0)
-                               die("BUG: ren1_dst != ren2_dst");
+                               BUG("ren1_dst != ren2_dst");
 
                        clean_merge = 0;
                        ren2->processed = 1;
@@ -2498,7 +2717,7 @@ static int process_renames(struct merge_options *o,
 
                        if (oid_eq(&src_other.oid, &null_oid) &&
                            ren1->add_turned_into_rename) {
-                               setup_rename_conflict_info(RENAME_DIR,
+                               setup_rename_conflict_info(RENAME_VIA_DIR,
                                                           ren1->pair,
                                                           NULL,
                                                           branch1,
@@ -2629,12 +2848,12 @@ static void initial_cleanup_rename(struct diff_queue_struct *pairs,
        free(pairs);
 }
 
-static int handle_renames(struct merge_options *o,
-                         struct tree *common,
-                         struct tree *head,
-                         struct tree *merge,
-                         struct string_list *entries,
-                         struct rename_info *ri)
+static int detect_and_process_renames(struct merge_options *o,
+                                     struct tree *common,
+                                     struct tree *head,
+                                     struct tree *merge,
+                                     struct string_list *entries,
+                                     struct rename_info *ri)
 {
        struct diff_queue_struct *head_pairs, *merge_pairs;
        struct hashmap *dir_re_head, *dir_re_merge;
@@ -2643,7 +2862,7 @@ static int handle_renames(struct merge_options *o,
        ri->head_renames = NULL;
        ri->merge_renames = NULL;
 
-       if (!o->detect_rename)
+       if (!merge_detect_rename(o))
                return 1;
 
        head_pairs = get_diffpairs(o, common, head);
@@ -2710,7 +2929,8 @@ static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
 }
 
 static int read_oid_strbuf(struct merge_options *o,
-       const struct object_id *oid, struct strbuf *dst)
+                          const struct object_id *oid,
+                          struct strbuf *dst)
 {
        void *buf;
        enum object_type type;
@@ -2763,10 +2983,10 @@ static int blob_unchanged(struct merge_options *opt,
 }
 
 static int handle_modify_delete(struct merge_options *o,
-                                const char *path,
-                                struct object_id *o_oid, int o_mode,
-                                struct object_id *a_oid, int a_mode,
-                                struct object_id *b_oid, int b_mode)
+                               const char *path,
+                               struct object_id *o_oid, int o_mode,
+                               struct object_id *a_oid, int a_mode,
+                               struct object_id *b_oid, int b_mode)
 {
        const char *modify_branch, *delete_branch;
        struct object_id *changed_oid;
@@ -2904,12 +3124,12 @@ static int merge_content(struct merge_options *o,
        return !is_dirty && mfi.clean;
 }
 
-static int conflict_rename_normal(struct merge_options *o,
-                                 const char *path,
-                                 struct object_id *o_oid, unsigned int o_mode,
-                                 struct object_id *a_oid, unsigned int a_mode,
-                                 struct object_id *b_oid, unsigned int b_mode,
-                                 struct rename_conflict_info *ci)
+static int handle_rename_normal(struct merge_options *o,
+                               const char *path,
+                               struct object_id *o_oid, unsigned int o_mode,
+                               struct object_id *a_oid, unsigned int a_mode,
+                               struct object_id *b_oid, unsigned int b_mode,
+                               struct rename_conflict_info *ci)
 {
        /* Merge the content and write it out */
        return merge_content(o, path, was_dirty(o, path),
@@ -2936,37 +3156,37 @@ static int process_entry(struct merge_options *o,
                switch (conflict_info->rename_type) {
                case RENAME_NORMAL:
                case RENAME_ONE_FILE_TO_ONE:
-                       clean_merge = conflict_rename_normal(o,
-                                                            path,
-                                                            o_oid, o_mode,
-                                                            a_oid, a_mode,
-                                                            b_oid, b_mode,
-                                                            conflict_info);
+                       clean_merge = handle_rename_normal(o,
+                                                          path,
+                                                          o_oid, o_mode,
+                                                          a_oid, a_mode,
+                                                          b_oid, b_mode,
+                                                          conflict_info);
                        break;
-               case RENAME_DIR:
+               case RENAME_VIA_DIR:
                        clean_merge = 1;
-                       if (conflict_rename_dir(o,
-                                               conflict_info->pair1,
-                                               conflict_info->branch1,
-                                               conflict_info->branch2))
+                       if (handle_rename_via_dir(o,
+                                                 conflict_info->pair1,
+                                                 conflict_info->branch1,
+                                                 conflict_info->branch2))
                                clean_merge = -1;
                        break;
                case RENAME_DELETE:
                        clean_merge = 0;
-                       if (conflict_rename_delete(o,
-                                                  conflict_info->pair1,
-                                                  conflict_info->branch1,
-                                                  conflict_info->branch2))
+                       if (handle_rename_delete(o,
+                                                conflict_info->pair1,
+                                                conflict_info->branch1,
+                                                conflict_info->branch2))
                                clean_merge = -1;
                        break;
                case RENAME_ONE_FILE_TO_TWO:
                        clean_merge = 0;
-                       if (conflict_rename_rename_1to2(o, conflict_info))
+                       if (handle_rename_rename_1to2(o, conflict_info))
                                clean_merge = -1;
                        break;
                case RENAME_TWO_FILES_TO_ONE:
                        clean_merge = 0;
-                       if (conflict_rename_rename_2to1(o, conflict_info))
+                       if (handle_rename_rename_2to1(o, conflict_info))
                                clean_merge = -1;
                        break;
                default:
@@ -3048,7 +3268,7 @@ static int process_entry(struct merge_options *o,
                 */
                remove_file(o, 1, path, !a_mode);
        } else
-               die("BUG: fatal merge failure, shouldn't happen.");
+               BUG("fatal merge failure, shouldn't happen.");
 
        return clean_merge;
 }
@@ -3079,13 +3299,14 @@ int merge_trees(struct merge_options *o,
                return 1;
        }
 
-       code = git_merge_trees(o, common, head, merge);
+       code = unpack_trees_start(o, common, head, merge);
 
        if (code != 0) {
                if (show(o, 4) || o->call_depth)
                        err(o, _("merging of trees %s and %s failed"),
                            oid_to_hex(&head->object.oid),
                            oid_to_hex(&merge->object.oid));
+               unpack_trees_finish(o);
                return -1;
        }
 
@@ -3105,8 +3326,8 @@ int merge_trees(struct merge_options *o,
                get_files_dirs(o, merge);
 
                entries = get_unmerged();
-               clean = handle_renames(o, common, head, merge, entries,
-                                      &re_info);
+               clean = detect_and_process_renames(o, common, head, merge,
+                                                  entries, &re_info);
                record_df_conflict_files(o, entries);
                if (clean < 0)
                        goto cleanup;
@@ -3126,11 +3347,11 @@ int merge_trees(struct merge_options *o,
                for (i = 0; i < entries->nr; i++) {
                        struct stage_data *e = entries->items[i].util;
                        if (!e->processed)
-                               die("BUG: unprocessed path??? %s",
+                               BUG("unprocessed path??? %s",
                                    entries->items[i].string);
                }
 
-cleanup:
+       cleanup:
                final_cleanup_renames(&re_info);
 
                string_list_clear(entries, 1);
@@ -3138,20 +3359,15 @@ int merge_trees(struct merge_options *o,
 
                hashmap_free(&o->current_file_dir_set, 1);
 
-               if (clean < 0)
+               if (clean < 0) {
+                       unpack_trees_finish(o);
                        return clean;
+               }
        }
        else
                clean = 1;
 
-       /* Free the extra index left from git_merge_trees() */
-       /*
-        * FIXME: Need to also free data allocated by
-        * setup_unpack_trees_porcelain() tucked away in o->unpack_opts.msgs,
-        * but the problem is that only half of it refers to dynamically
-        * allocated data, while the other half points at static strings.
-        */
-       discard_index(&o->orig_index);
+       unpack_trees_finish(o);
 
        if (o->call_depth && !(*result = write_tree_from_memory(o)))
                return -1;
@@ -3246,7 +3462,8 @@ int merge_recursive(struct merge_options *o,
                read_cache();
 
        o->ancestor = "merged common ancestors";
-       clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
+       clean = merge_trees(o, get_commit_tree(h1), get_commit_tree(h2),
+                           get_commit_tree(merged_common_ancestors),
                            &mrtree);
        if (clean < 0) {
                flush_output(o);
@@ -3302,14 +3519,14 @@ int merge_recursive_generic(struct merge_options *o,
                        struct commit *base;
                        if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
                                return err(o, _("Could not parse object '%s'"),
-                                       oid_to_hex(base_list[i]));
+                                          oid_to_hex(base_list[i]));
                        commit_list_insert(base, &ca);
                }
        }
 
        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
        clean = merge_recursive(o, head_commit, next_commit, ca,
-                       result);
+                               result);
        if (clean < 0) {
                rollback_lock_file(&lock);
                return clean;
@@ -3324,9 +3541,18 @@ int merge_recursive_generic(struct merge_options *o,
 
 static void merge_recursive_config(struct merge_options *o)
 {
+       char *value = NULL;
        git_config_get_int("merge.verbosity", &o->verbosity);
        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
+       if (!git_config_get_string("diff.renames", &value)) {
+               o->diff_detect_rename = git_config_rename("diff.renames", value);
+               free(value);
+       }
+       if (!git_config_get_string("merge.renames", &value)) {
+               o->merge_detect_rename = git_config_rename("merge.renames", value);
+               free(value);
+       }
        git_config(git_xmerge_config, NULL);
 }
 
@@ -3339,7 +3565,8 @@ void init_merge_options(struct merge_options *o)
        o->diff_rename_limit = -1;
        o->merge_rename_limit = -1;
        o->renormalize = 0;
-       o->detect_rename = 1;
+       o->diff_detect_rename = -1;
+       o->merge_detect_rename = -1;
        merge_recursive_config(o);
        merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
        if (merge_verbosity)
@@ -3390,16 +3617,16 @@ int parse_merge_opt(struct merge_options *o, const char *s)
        else if (!strcmp(s, "no-renormalize"))
                o->renormalize = 0;
        else if (!strcmp(s, "no-renames"))
-               o->detect_rename = 0;
+               o->merge_detect_rename = 0;
        else if (!strcmp(s, "find-renames")) {
-               o->detect_rename = 1;
+               o->merge_detect_rename = 1;
                o->rename_score = 0;
        }
        else if (skip_prefix(s, "find-renames=", &arg) ||
                 skip_prefix(s, "rename-threshold=", &arg)) {
                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
                        return -1;
-               o->detect_rename = 1;
+               o->merge_detect_rename = 1;
        }
        else
                return -1;