grep: recurse in-process using 'struct repository'
[gitweb.git] / ref-filter.c
index 238888e4de342c601b26650251a235ffeb3190f2..ae6ecbd1cfe42936b22488d7761e4e487e2922ca 100644 (file)
@@ -15,6 +15,7 @@
 #include "version.h"
 #include "trailer.h"
 #include "wt-status.h"
+#include "commit-slab.h"
 
 static struct ref_msg {
        const char *gone;
@@ -289,9 +290,9 @@ static void if_atom_parser(struct used_atom *atom, const char *arg)
 
 static void head_atom_parser(struct used_atom *atom, const char *arg)
 {
-       unsigned char unused[GIT_SHA1_RAWSZ];
+       struct object_id unused;
 
-       atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, unused, NULL);
+       atom->u.head = resolve_refdup("HEAD", RESOLVE_REF_READING, unused.hash, NULL);
 }
 
 static struct {
@@ -357,7 +358,7 @@ struct ref_formatting_state {
 struct atom_value {
        const char *s;
        void (*handler)(struct atom_value *atomv, struct ref_formatting_state *state);
-       unsigned long ul; /* used for sorting when not FIELD_STR */
+       uintmax_t value; /* used for sorting when not FIELD_STR */
        struct used_atom *atom;
 };
 
@@ -683,13 +684,13 @@ int verify_ref_format(const char *format)
  * by the "struct object" representation, set *eaten as well---it is a
  * signal from parse_object_buffer to us not to free the buffer.
  */
-static void *get_obj(const unsigned char *sha1, struct object **obj, unsigned long *sz, int *eaten)
+static void *get_obj(const struct object_id *oid, struct object **obj, unsigned long *sz, int *eaten)
 {
        enum object_type type;
-       void *buf = read_sha1_file(sha1, &type, sz);
+       void *buf = read_sha1_file(oid->hash, &type, sz);
 
        if (buf)
-               *obj = parse_object_buffer(sha1, type, *sz, buf, eaten);
+               *obj = parse_object_buffer(oid, type, *sz, buf, eaten);
        else
                *obj = NULL;
        return buf;
@@ -729,7 +730,7 @@ static void grab_common_values(struct atom_value *val, int deref, struct object
                if (!strcmp(name, "objecttype"))
                        v->s = typename(obj->type);
                else if (!strcmp(name, "objectsize")) {
-                       v->ul = sz;
+                       v->value = sz;
                        v->s = xstrfmt("%lu", sz);
                }
                else if (deref)
@@ -776,8 +777,8 @@ static void grab_commit_values(struct atom_value *val, int deref, struct object
                        v->s = xstrdup(oid_to_hex(&commit->tree->object.oid));
                }
                else if (!strcmp(name, "numparent")) {
-                       v->ul = commit_list_count(commit->parents);
-                       v->s = xstrfmt("%lu", v->ul);
+                       v->value = commit_list_count(commit->parents);
+                       v->s = xstrfmt("%lu", (unsigned long)v->value);
                }
                else if (!strcmp(name, "parent")) {
                        struct commit_list *parents;
@@ -855,7 +856,7 @@ static void grab_date(const char *buf, struct atom_value *v, const char *atomnam
 {
        const char *eoemail = strstr(buf, "> ");
        char *zone;
-       unsigned long timestamp;
+       timestamp_t timestamp;
        long tz;
        struct date_mode date_mode = { DATE_NORMAL };
        const char *formatp;
@@ -874,18 +875,18 @@ static void grab_date(const char *buf, struct atom_value *v, const char *atomnam
 
        if (!eoemail)
                goto bad;
-       timestamp = strtoul(eoemail + 2, &zone, 10);
-       if (timestamp == ULONG_MAX)
+       timestamp = parse_timestamp(eoemail + 2, &zone, 10);
+       if (timestamp == TIME_MAX)
                goto bad;
        tz = strtol(zone, NULL, 10);
        if ((tz == LONG_MIN || tz == LONG_MAX) && errno == ERANGE)
                goto bad;
        v->s = xstrdup(show_date(timestamp, tz, &date_mode));
-       v->ul = timestamp;
+       v->value = timestamp;
        return;
  bad:
        v->s = "";
-       v->ul = 0;
+       v->value = 0;
 }
 
 /* See grab_values */
@@ -1256,12 +1257,18 @@ char *get_head_description(void)
                strbuf_addf(&desc, _("(no branch, bisect started on %s)"),
                            state.branch);
        else if (state.detached_from) {
-               /* TRANSLATORS: make sure these match _("HEAD detached at ")
-                  and _("HEAD detached from ") in wt-status.c */
                if (state.detached_at)
+                       /*
+                        * TRANSLATORS: make sure this matches "HEAD
+                        * detached at " in wt-status.c
+                        */
                        strbuf_addf(&desc, _("(HEAD detached at %s)"),
                                state.detached_from);
                else
+                       /*
+                        * TRANSLATORS: make sure this matches "HEAD
+                        * detached from " in wt-status.c
+                        */
                        strbuf_addf(&desc, _("(HEAD detached from %s)"),
                                state.detached_from);
        }
@@ -1297,14 +1304,14 @@ static void populate_value(struct ref_array_item *ref)
        struct object *obj;
        int eaten, i;
        unsigned long size;
-       const unsigned char *tagged;
+       const struct object_id *tagged;
 
        ref->value = xcalloc(used_atom_cnt, sizeof(struct atom_value));
 
        if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
-               unsigned char unused1[20];
+               struct object_id unused1;
                ref->symref = resolve_refdup(ref->refname, RESOLVE_REF_READING,
-                                            unused1, NULL);
+                                            unused1.hash, NULL);
                if (!ref->symref)
                        ref->symref = "";
        }
@@ -1370,7 +1377,7 @@ static void populate_value(struct ref_array_item *ref)
                                v->s = xstrdup(buf + 1);
                        }
                        continue;
-               } else if (!deref && grab_objectname(name, ref->objectname, v, atom)) {
+               } else if (!deref && grab_objectname(name, ref->objectname.hash, v, atom)) {
                        continue;
                } else if (!strcmp(name, "HEAD")) {
                        if (atom->u.head && !strcmp(ref->refname, atom->u.head))
@@ -1414,13 +1421,13 @@ static void populate_value(struct ref_array_item *ref)
        return;
 
  need_obj:
-       buf = get_obj(ref->objectname, &obj, &size, &eaten);
+       buf = get_obj(&ref->objectname, &obj, &size, &eaten);
        if (!buf)
                die(_("missing object %s for %s"),
-                   sha1_to_hex(ref->objectname), ref->refname);
+                   oid_to_hex(&ref->objectname), ref->refname);
        if (!obj)
                die(_("parse_object_buffer failed on %s for %s"),
-                   sha1_to_hex(ref->objectname), ref->refname);
+                   oid_to_hex(&ref->objectname), ref->refname);
 
        grab_values(ref->value, 0, obj, buf, size);
        if (!eaten)
@@ -1437,7 +1444,7 @@ static void populate_value(struct ref_array_item *ref)
         * If it is a tag object, see if we use a value that derefs
         * the object, and if we do grab the object it refers to.
         */
-       tagged = ((struct tag *)obj)->tagged->oid.hash;
+       tagged = &((struct tag *)obj)->tagged->oid;
 
        /*
         * NEEDSWORK: This derefs tag only once, which
@@ -1448,10 +1455,10 @@ static void populate_value(struct ref_array_item *ref)
        buf = get_obj(tagged, &obj, &size, &eaten);
        if (!buf)
                die(_("missing object %s for %s"),
-                   sha1_to_hex(tagged), ref->refname);
+                   oid_to_hex(tagged), ref->refname);
        if (!obj)
                die(_("parse_object_buffer failed on %s for %s"),
-                   sha1_to_hex(tagged), ref->refname);
+                   oid_to_hex(tagged), ref->refname);
        grab_values(ref->value, 1, obj, buf, size);
        if (!eaten)
                free(buf);
@@ -1470,10 +1477,23 @@ static void get_ref_atom_value(struct ref_array_item *ref, int atom, struct atom
        *v = &ref->value[atom];
 }
 
+/*
+ * Unknown has to be "0" here, because that's the default value for
+ * contains_cache slab entries that have not yet been assigned.
+ */
 enum contains_result {
-       CONTAINS_UNKNOWN = -1,
-       CONTAINS_NO = 0,
-       CONTAINS_YES = 1
+       CONTAINS_UNKNOWN = 0,
+       CONTAINS_NO,
+       CONTAINS_YES
+};
+
+define_commit_slab(contains_cache, enum contains_result);
+
+struct ref_filter_cbdata {
+       struct ref_array *array;
+       struct ref_filter *filter;
+       struct contains_cache contains_cache;
+       struct contains_cache no_contains_cache;
 };
 
 /*
@@ -1504,24 +1524,24 @@ static int in_commit_list(const struct commit_list *want, struct commit *c)
  * Do not recurse to find out, though, but return -1 if inconclusive.
  */
 static enum contains_result contains_test(struct commit *candidate,
-                           const struct commit_list *want)
+                                         const struct commit_list *want,
+                                         struct contains_cache *cache)
 {
-       /* was it previously marked as containing a want commit? */
-       if (candidate->object.flags & TMP_MARK)
-               return 1;
-       /* or marked as not possibly containing a want commit? */
-       if (candidate->object.flags & UNINTERESTING)
-               return 0;
+       enum contains_result *cached = contains_cache_at(cache, candidate);
+
+       /* If we already have the answer cached, return that. */
+       if (*cached)
+               return *cached;
+
        /* or are we it? */
        if (in_commit_list(want, candidate)) {
-               candidate->object.flags |= TMP_MARK;
-               return 1;
+               *cached = CONTAINS_YES;
+               return CONTAINS_YES;
        }
 
-       if (parse_commit(candidate) < 0)
-               return 0;
-
-       return -1;
+       /* Otherwise, we don't know; prepare to recurse */
+       parse_commit_or_die(candidate);
+       return CONTAINS_UNKNOWN;
 }
 
 static void push_to_contains_stack(struct commit *candidate, struct contains_stack *contains_stack)
@@ -1532,10 +1552,11 @@ static void push_to_contains_stack(struct commit *candidate, struct contains_sta
 }
 
 static enum contains_result contains_tag_algo(struct commit *candidate,
-               const struct commit_list *want)
+                                             const struct commit_list *want,
+                                             struct contains_cache *cache)
 {
        struct contains_stack contains_stack = { 0, 0, NULL };
-       int result = contains_test(candidate, want);
+       enum contains_result result = contains_test(candidate, want, cache);
 
        if (result != CONTAINS_UNKNOWN)
                return result;
@@ -1547,16 +1568,16 @@ static enum contains_result contains_tag_algo(struct commit *candidate,
                struct commit_list *parents = entry->parents;
 
                if (!parents) {
-                       commit->object.flags |= UNINTERESTING;
+                       *contains_cache_at(cache, commit) = CONTAINS_NO;
                        contains_stack.nr--;
                }
                /*
                 * If we just popped the stack, parents->item has been marked,
-                * therefore contains_test will return a meaningful 0 or 1.
+                * therefore contains_test will return a meaningful yes/no.
                 */
-               else switch (contains_test(parents->item, want)) {
+               else switch (contains_test(parents->item, want, cache)) {
                case CONTAINS_YES:
-                       commit->object.flags |= TMP_MARK;
+                       *contains_cache_at(cache, commit) = CONTAINS_YES;
                        contains_stack.nr--;
                        break;
                case CONTAINS_NO:
@@ -1568,14 +1589,15 @@ static enum contains_result contains_tag_algo(struct commit *candidate,
                }
        }
        free(contains_stack.contains_stack);
-       return contains_test(candidate, want);
+       return contains_test(candidate, want, cache);
 }
 
-static int commit_contains(struct ref_filter *filter, struct commit *commit)
+static int commit_contains(struct ref_filter *filter, struct commit *commit,
+                          struct commit_list *list, struct contains_cache *cache)
 {
        if (filter->with_commit_tag_algo)
-               return contains_tag_algo(commit, filter->with_commit);
-       return is_descendant_of(commit, filter->with_commit);
+               return contains_tag_algo(commit, list, cache) == CONTAINS_YES;
+       return is_descendant_of(commit, list);
 }
 
 /*
@@ -1602,7 +1624,7 @@ static int match_pattern(const struct ref_filter *filter, const char *refname)
               skip_prefix(refname, "refs/", &refname));
 
        for (; *patterns; patterns++) {
-               if (!wildmatch(*patterns, refname, flags, NULL))
+               if (!wildmatch(*patterns, refname, flags))
                        return 1;
        }
        return 0;
@@ -1633,7 +1655,7 @@ static int match_name_as_path(const struct ref_filter *filter, const char *refna
                     refname[plen] == '/' ||
                     p[plen-1] == '/'))
                        return 1;
-               if (!wildmatch(p, refname, WM_PATHNAME, NULL))
+               if (!wildmatch(p, refname, WM_PATHNAME))
                        return 1;
        }
        return 0;
@@ -1649,6 +1671,68 @@ static int filter_pattern_match(struct ref_filter *filter, const char *refname)
        return match_pattern(filter, refname);
 }
 
+/*
+ * Find the longest prefix of pattern we can pass to
+ * `for_each_fullref_in()`, namely the part of pattern preceding the
+ * first glob character. (Note that `for_each_fullref_in()` is
+ * perfectly happy working with a prefix that doesn't end at a
+ * pathname component boundary.)
+ */
+static void find_longest_prefix(struct strbuf *out, const char *pattern)
+{
+       const char *p;
+
+       for (p = pattern; *p && !is_glob_special(*p); p++)
+               ;
+
+       strbuf_add(out, pattern, p - pattern);
+}
+
+/*
+ * This is the same as for_each_fullref_in(), but it tries to iterate
+ * only over the patterns we'll care about. Note that it _doesn't_ do a full
+ * pattern match, so the callback still has to match each ref individually.
+ */
+static int for_each_fullref_in_pattern(struct ref_filter *filter,
+                                      each_ref_fn cb,
+                                      void *cb_data,
+                                      int broken)
+{
+       struct strbuf prefix = STRBUF_INIT;
+       int ret;
+
+       if (!filter->match_as_path) {
+               /*
+                * in this case, the patterns are applied after
+                * prefixes like "refs/heads/" etc. are stripped off,
+                * so we have to look at everything:
+                */
+               return for_each_fullref_in("", cb, cb_data, broken);
+       }
+
+       if (!filter->name_patterns[0]) {
+               /* no patterns; we have to look at everything */
+               return for_each_fullref_in("", cb, cb_data, broken);
+       }
+
+       if (filter->name_patterns[1]) {
+               /*
+                * multiple patterns; in theory this could still work as long
+                * as the patterns are disjoint. We'd just make multiple calls
+                * to for_each_ref(). But if they're not disjoint, we'd end up
+                * reporting the same ref multiple times. So let's punt on that
+                * for now.
+                */
+               return for_each_fullref_in("", cb, cb_data, broken);
+       }
+
+       find_longest_prefix(&prefix, filter->name_patterns[0]);
+
+       ret = for_each_fullref_in(prefix.buf, cb, cb_data, broken);
+       strbuf_release(&prefix);
+       return ret;
+}
+
 /*
  * Given a ref (sha1, refname), check if the ref belongs to the array
  * of sha1s. If the given ref is a tag, check if the given tag points
@@ -1662,22 +1746,22 @@ static int filter_pattern_match(struct ref_filter *filter, const char *refname)
  * the need to parse the object via parse_object(). peel_ref() might be a
  * more efficient alternative to obtain the pointee.
  */
-static const unsigned char *match_points_at(struct sha1_array *points_at,
-                                           const unsigned char *sha1,
-                                           const char *refname)
+static const struct object_id *match_points_at(struct oid_array *points_at,
+                                              const struct object_id *oid,
+                                              const char *refname)
 {
-       const unsigned char *tagged_sha1 = NULL;
+       const struct object_id *tagged_oid = NULL;
        struct object *obj;
 
-       if (sha1_array_lookup(points_at, sha1) >= 0)
-               return sha1;
-       obj = parse_object(sha1);
+       if (oid_array_lookup(points_at, oid) >= 0)
+               return oid;
+       obj = parse_object(oid);
        if (!obj)
                die(_("malformed object at '%s'"), refname);
        if (obj->type == OBJ_TAG)
-               tagged_sha1 = ((struct tag *)obj)->tagged->oid.hash;
-       if (tagged_sha1 && sha1_array_lookup(points_at, tagged_sha1) >= 0)
-               return tagged_sha1;
+               tagged_oid = &((struct tag *)obj)->tagged->oid;
+       if (tagged_oid && oid_array_lookup(points_at, tagged_oid) >= 0)
+               return tagged_oid;
        return NULL;
 }
 
@@ -1688,13 +1772,13 @@ static struct ref_array_item *new_ref_array_item(const char *refname,
 {
        struct ref_array_item *ref;
        FLEX_ALLOC_STR(ref, refname, refname);
-       hashcpy(ref->objectname, objectname);
+       hashcpy(ref->objectname.hash, objectname);
        ref->flag = flag;
 
        return ref;
 }
 
-static int filter_ref_kind(struct ref_filter *filter, const char *refname)
+static int ref_kind_from_refname(const char *refname)
 {
        unsigned int i;
 
@@ -1707,11 +1791,7 @@ static int filter_ref_kind(struct ref_filter *filter, const char *refname)
                { "refs/tags/", FILTER_REFS_TAGS}
        };
 
-       if (filter->kind == FILTER_REFS_BRANCHES ||
-           filter->kind == FILTER_REFS_REMOTES ||
-           filter->kind == FILTER_REFS_TAGS)
-               return filter->kind;
-       else if (!strcmp(refname, "HEAD"))
+       if (!strcmp(refname, "HEAD"))
                return FILTER_REFS_DETACHED_HEAD;
 
        for (i = 0; i < ARRAY_SIZE(ref_kind); i++) {
@@ -1722,6 +1802,15 @@ static int filter_ref_kind(struct ref_filter *filter, const char *refname)
        return FILTER_REFS_OTHERS;
 }
 
+static int filter_ref_kind(struct ref_filter *filter, const char *refname)
+{
+       if (filter->kind == FILTER_REFS_BRANCHES ||
+           filter->kind == FILTER_REFS_REMOTES ||
+           filter->kind == FILTER_REFS_TAGS)
+               return filter->kind;
+       return ref_kind_from_refname(refname);
+}
+
 /*
  * A call-back given to for_each_ref().  Filter refs and keep them for
  * later object processing.
@@ -1752,7 +1841,7 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
        if (!filter_pattern_match(filter, refname))
                return 0;
 
-       if (filter->points_at.nr && !match_points_at(&filter->points_at, oid->hash, refname))
+       if (filter->points_at.nr && !match_points_at(&filter->points_at, oid, refname))
                return 0;
 
        /*
@@ -1760,13 +1849,17 @@ static int ref_filter_handler(const char *refname, const struct object_id *oid,
         * obtain the commit using the 'oid' available and discard all
         * non-commits early. The actual filtering is done later.
         */
-       if (filter->merge_commit || filter->with_commit || filter->verbose) {
-               commit = lookup_commit_reference_gently(oid->hash, 1);
+       if (filter->merge_commit || filter->with_commit || filter->no_commit || filter->verbose) {
+               commit = lookup_commit_reference_gently(oid, 1);
                if (!commit)
                        return 0;
-               /* We perform the filtering for the '--contains' option */
+               /* We perform the filtering for the '--contains' option... */
                if (filter->with_commit &&
-                   !commit_contains(filter, commit))
+                   !commit_contains(filter, commit, filter->with_commit, &ref_cbdata->contains_cache))
+                       return 0;
+               /* ...or for the `--no-contains' option */
+               if (filter->no_commit &&
+                   commit_contains(filter, commit, filter->no_commit, &ref_cbdata->no_contains_cache))
                        return 0;
        }
 
@@ -1798,8 +1891,7 @@ void ref_array_clear(struct ref_array *array)
 
        for (i = 0; i < array->nr; i++)
                free_array_item(array->items[i]);
-       free(array->items);
-       array->items = NULL;
+       FREE_AND_NULL(array->items);
        array->nr = array->alloc = 0;
 }
 
@@ -1866,6 +1958,9 @@ int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int
                broken = 1;
        filter->kind = type & FILTER_REFS_KIND_MASK;
 
+       init_contains_cache(&ref_cbdata.contains_cache);
+       init_contains_cache(&ref_cbdata.no_contains_cache);
+
        /*  Simple per-ref filtering */
        if (!filter->kind)
                die("filter_refs: invalid type");
@@ -1883,11 +1978,13 @@ int filter_refs(struct ref_array *array, struct ref_filter *filter, unsigned int
                else if (filter->kind == FILTER_REFS_TAGS)
                        ret = for_each_fullref_in("refs/tags/", ref_filter_handler, &ref_cbdata, broken);
                else if (filter->kind & FILTER_REFS_ALL)
-                       ret = for_each_fullref_in("", ref_filter_handler, &ref_cbdata, broken);
+                       ret = for_each_fullref_in_pattern(filter, ref_filter_handler, &ref_cbdata, broken);
                if (!ret && (filter->kind & FILTER_REFS_DETACHED_HEAD))
                        head_ref(ref_filter_handler, &ref_cbdata);
        }
 
+       clear_contains_cache(&ref_cbdata.contains_cache);
+       clear_contains_cache(&ref_cbdata.no_contains_cache);
 
        /*  Filters that need revision walking */
        if (filter->merge_commit)
@@ -1911,9 +2008,9 @@ static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, stru
        else if (cmp_type == FIELD_STR)
                cmp = cmp_fn(va->s, vb->s);
        else {
-               if (va->ul < vb->ul)
+               if (va->value < vb->value)
                        cmp = -1;
-               else if (va->ul == vb->ul)
+               else if (va->value == vb->value)
                        cmp = cmp_fn(a->refname, b->refname);
                else
                        cmp = 1;
@@ -1922,8 +2019,7 @@ static int cmp_ref_sorting(struct ref_sorting *s, struct ref_array_item *a, stru
        return (s->reverse) ? -cmp : cmp;
 }
 
-static struct ref_sorting *ref_sorting;
-static int compare_refs(const void *a_, const void *b_)
+static int compare_refs(const void *a_, const void *b_, void *ref_sorting)
 {
        struct ref_array_item *a = *((struct ref_array_item **)a_);
        struct ref_array_item *b = *((struct ref_array_item **)b_);
@@ -1939,8 +2035,7 @@ static int compare_refs(const void *a_, const void *b_)
 
 void ref_array_sort(struct ref_sorting *sorting, struct ref_array *array)
 {
-       ref_sorting = sorting;
-       QSORT(array->items, array->nr, compare_refs);
+       QSORT_S(array->items, array->nr, compare_refs, sorting);
 }
 
 static void append_literal(const char *cp, const char *ep, struct ref_formatting_state *state)
@@ -2012,6 +2107,16 @@ void show_ref_array_item(struct ref_array_item *info, const char *format, int qu
        putchar('\n');
 }
 
+void pretty_print_ref(const char *name, const unsigned char *sha1,
+               const char *format)
+{
+       struct ref_array_item *ref_item;
+       ref_item = new_ref_array_item(name, sha1, 0);
+       ref_item->kind = ref_kind_from_refname(name);
+       show_ref_array_item(ref_item, format, 0);
+       free_array_item(ref_item);
+}
+
 /*  If no sorting option is given, use refname to sort as default */
 struct ref_sorting *ref_default_sorting(void)
 {
@@ -2052,16 +2157,25 @@ int parse_opt_ref_sorting(const struct option *opt, const char *arg, int unset)
 int parse_opt_merge_filter(const struct option *opt, const char *arg, int unset)
 {
        struct ref_filter *rf = opt->value;
-       unsigned char sha1[20];
+       struct object_id oid;
+       int no_merged = starts_with(opt->long_name, "no");
+
+       if (rf->merge) {
+               if (no_merged) {
+                       return opterror(opt, "is incompatible with --merged", 0);
+               } else {
+                       return opterror(opt, "is incompatible with --no-merged", 0);
+               }
+       }
 
-       rf->merge = starts_with(opt->long_name, "no")
+       rf->merge = no_merged
                ? REF_FILTER_MERGED_OMIT
                : REF_FILTER_MERGED_INCLUDE;
 
-       if (get_sha1(arg, sha1))
+       if (get_oid(arg, &oid))
                die(_("malformed object name %s"), arg);
 
-       rf->merge_commit = lookup_commit_reference_gently(sha1, 0);
+       rf->merge_commit = lookup_commit_reference_gently(&oid, 0);
        if (!rf->merge_commit)
                return opterror(opt, "must point to a commit", 0);