builtin/fmt-merge-msg.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "refs.h"
   5 #include "object-store.h"
   6 #include "commit.h"
   7 #include "diff.h"
   8 #include "revision.h"
   9 #include "tag.h"
  10 #include "string-list.h"
  11 #include "branch.h"
  12 #include "fmt-merge-msg.h"
  13 #include "gpg-interface.h"
  14 #include "repository.h"
  15
  16 static const char * const fmt_merge_msg_usage[] = {
  17         N_("git fmt-merge-msg [-m <message>] [--log[=<n>] | --no-log] [--file <file>]"),
  18         NULL
  19 };
  20
  21 static int use_branch_desc;
  22
  23 int fmt_merge_msg_config(const char *key, const char *value, void *cb)
  24 {
  25         if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
  26                 int is_bool;
  27                 merge_log_config = git_config_bool_or_int(key, value, &is_bool);
  28                 if (!is_bool && merge_log_config < 0)
  29                         return error("%s: negative length %s", key, value);
  30                 if (is_bool && merge_log_config)
  31                         merge_log_config = DEFAULT_MERGE_LOG_LEN;
  32         } else if (!strcmp(key, "merge.branchdesc")) {
  33                 use_branch_desc = git_config_bool(key, value);
  34         } else {
  35                 return git_default_config(key, value, cb);
  36         }
  37         return 0;
  38 }
  39
  40 /* merge data per repository where the merged tips came from */
  41 struct src_data {
  42         struct string_list branch, tag, r_branch, generic;
  43         int head_status;
  44 };
  45
  46 struct origin_data {
  47         struct object_id oid;
  48         unsigned is_local_branch:1;
  49 };
  50
  51 static void init_src_data(struct src_data *data)
  52 {
  53         data->branch.strdup_strings = 1;
  54         data->tag.strdup_strings = 1;
  55         data->r_branch.strdup_strings = 1;
  56         data->generic.strdup_strings = 1;
  57 }
  58
  59 static struct string_list srcs = STRING_LIST_INIT_DUP;
  60 static struct string_list origins = STRING_LIST_INIT_DUP;
  61
  62 struct merge_parents {
  63         int alloc, nr;
  64         struct merge_parent {
  65                 struct object_id given;
  66                 struct object_id commit;
  67                 unsigned char used;
  68         } *item;
  69 };
  70
  71 /*
  72  * I know, I know, this is inefficient, but you won't be pulling and merging
  73  * hundreds of heads at a time anyway.
  74  */
  75 static struct merge_parent *find_merge_parent(struct merge_parents *table,
  76                                               struct object_id *given,
  77                                               struct object_id *commit)
  78 {
  79         int i;
  80         for (i = 0; i < table->nr; i++) {
  81                 if (given && oidcmp(&table->item[i].given, given))
  82                         continue;
  83                 if (commit && oidcmp(&table->item[i].commit, commit))
  84                         continue;
  85                 return &table->item[i];
  86         }
  87         return NULL;
  88 }
  89
  90 static void add_merge_parent(struct merge_parents *table,
  91                              struct object_id *given,
  92                              struct object_id *commit)
  93 {
  94         if (table->nr && find_merge_parent(table, given, commit))
  95                 return;
  96         ALLOC_GROW(table->item, table->nr + 1, table->alloc);
  97         oidcpy(&table->item[table->nr].given, given);
  98         oidcpy(&table->item[table->nr].commit, commit);
  99         table->item[table->nr].used = 0;
 100         table->nr++;
 101 }
 102
 103 static int handle_line(char *line, struct merge_parents *merge_parents)
 104 {
 105         int i, len = strlen(line);
 106         struct origin_data *origin_data;
 107         char *src;
 108         const char *origin;
 109         struct src_data *src_data;
 110         struct string_list_item *item;
 111         int pulling_head = 0;
 112         struct object_id oid;
 113
 114         if (len < GIT_SHA1_HEXSZ + 3 || line[GIT_SHA1_HEXSZ] != '\t')
 115                 return 1;
 116
 117         if (starts_with(line + GIT_SHA1_HEXSZ + 1, "not-for-merge"))
 118                 return 0;
 119
 120         if (line[GIT_SHA1_HEXSZ + 1] != '\t')
 121                 return 2;
 122
 123         i = get_oid_hex(line, &oid);
 124         if (i)
 125                 return 3;
 126
 127         if (!find_merge_parent(merge_parents, &oid, NULL))
 128                 return 0; /* subsumed by other parents */
 129
 130         origin_data = xcalloc(1, sizeof(struct origin_data));
 131         oidcpy(&origin_data->oid, &oid);
 132
 133         if (line[len - 1] == '\n')
 134                 line[len - 1] = 0;
 135         line += GIT_SHA1_HEXSZ + 2;
 136
 137         /*
 138          * At this point, line points at the beginning of comment e.g.
 139          * "branch 'frotz' of git://that/repository.git".
 140          * Find the repository name and point it with src.
 141          */
 142         src = strstr(line, " of ");
 143         if (src) {
 144                 *src = 0;
 145                 src += 4;
 146                 pulling_head = 0;
 147         } else {
 148                 src = line;
 149                 pulling_head = 1;
 150         }
 151
 152         item = unsorted_string_list_lookup(&srcs, src);
 153         if (!item) {
 154                 item = string_list_append(&srcs, src);
 155                 item->util = xcalloc(1, sizeof(struct src_data));
 156                 init_src_data(item->util);
 157         }
 158         src_data = item->util;
 159
 160         if (pulling_head) {
 161                 origin = src;
 162                 src_data->head_status |= 1;
 163         } else if (starts_with(line, "branch ")) {
 164                 origin_data->is_local_branch = 1;
 165                 origin = line + 7;
 166                 string_list_append(&src_data->branch, origin);
 167                 src_data->head_status |= 2;
 168         } else if (starts_with(line, "tag ")) {
 169                 origin = line;
 170                 string_list_append(&src_data->tag, origin + 4);
 171                 src_data->head_status |= 2;
 172         } else if (skip_prefix(line, "remote-tracking branch ", &origin)) {
 173                 string_list_append(&src_data->r_branch, origin);
 174                 src_data->head_status |= 2;
 175         } else {
 176                 origin = src;
 177                 string_list_append(&src_data->generic, line);
 178                 src_data->head_status |= 2;
 179         }
 180
 181         if (!strcmp(".", src) || !strcmp(src, origin)) {
 182                 int len = strlen(origin);
 183                 if (origin[0] == '\'' && origin[len - 1] == '\'')
 184                         origin = xmemdupz(origin + 1, len - 2);
 185         } else
 186                 origin = xstrfmt("%s of %s", origin, src);
 187         if (strcmp(".", src))
 188                 origin_data->is_local_branch = 0;
 189         string_list_append(&origins, origin)->util = origin_data;
 190         return 0;
 191 }
 192
 193 static void print_joined(const char *singular, const char *plural,
 194                 struct string_list *list, struct strbuf *out)
 195 {
 196         if (list->nr == 0)
 197                 return;
 198         if (list->nr == 1) {
 199                 strbuf_addf(out, "%s%s", singular, list->items[0].string);
 200         } else {
 201                 int i;
 202                 strbuf_addstr(out, plural);
 203                 for (i = 0; i < list->nr - 1; i++)
 204                         strbuf_addf(out, "%s%s", i > 0 ? ", " : "",
 205                                     list->items[i].string);
 206                 strbuf_addf(out, " and %s", list->items[list->nr - 1].string);
 207         }
 208 }
 209
 210 static void add_branch_desc(struct strbuf *out, const char *name)
 211 {
 212         struct strbuf desc = STRBUF_INIT;
 213
 214         if (!read_branch_desc(&desc, name)) {
 215                 const char *bp = desc.buf;
 216                 while (*bp) {
 217                         const char *ep = strchrnul(bp, '\n');
 218                         if (*ep)
 219                                 ep++;
 220                         strbuf_addf(out, "  : %.*s", (int)(ep - bp), bp);
 221                         bp = ep;
 222                 }
 223                 strbuf_complete_line(out);
 224         }
 225         strbuf_release(&desc);
 226 }
 227
 228 #define util_as_integral(elem) ((intptr_t)((elem)->util))
 229
 230 static void record_person_from_buf(int which, struct string_list *people,
 231                                    const char *buffer)
 232 {
 233         char *name_buf, *name, *name_end;
 234         struct string_list_item *elem;
 235         const char *field;
 236
 237         field = (which == 'a') ? "\nauthor " : "\ncommitter ";
 238         name = strstr(buffer, field);
 239         if (!name)
 240                 return;
 241         name += strlen(field);
 242         name_end = strchrnul(name, '<');
 243         if (*name_end)
 244                 name_end--;
 245         while (isspace(*name_end) && name <= name_end)
 246                 name_end--;
 247         if (name_end < name)
 248                 return;
 249         name_buf = xmemdupz(name, name_end - name + 1);
 250
 251         elem = string_list_lookup(people, name_buf);
 252         if (!elem) {
 253                 elem = string_list_insert(people, name_buf);
 254                 elem->util = (void *)0;
 255         }
 256         elem->util = (void*)(util_as_integral(elem) + 1);
 257         free(name_buf);
 258 }
 259
 260
 261 static void record_person(int which, struct string_list *people,
 262                           struct commit *commit)
 263 {
 264         const char *buffer = get_commit_buffer(commit, NULL);
 265         record_person_from_buf(which, people, buffer);
 266         unuse_commit_buffer(commit, buffer);
 267 }
 268
 269 static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
 270 {
 271         const struct string_list_item *a = a_, *b = b_;
 272         return util_as_integral(b) - util_as_integral(a);
 273 }
 274
 275 static void add_people_count(struct strbuf *out, struct string_list *people)
 276 {
 277         if (people->nr == 1)
 278                 strbuf_addstr(out, people->items[0].string);
 279         else if (people->nr == 2)
 280                 strbuf_addf(out, "%s (%d) and %s (%d)",
 281                             people->items[0].string,
 282                             (int)util_as_integral(&people->items[0]),
 283                             people->items[1].string,
 284                             (int)util_as_integral(&people->items[1]));
 285         else if (people->nr)
 286                 strbuf_addf(out, "%s (%d) and others",
 287                             people->items[0].string,
 288                             (int)util_as_integral(&people->items[0]));
 289 }
 290
 291 static void credit_people(struct strbuf *out,
 292                           struct string_list *them,
 293                           int kind)
 294 {
 295         const char *label;
 296         const char *me;
 297
 298         if (kind == 'a') {
 299                 label = "By";
 300                 me = git_author_info(IDENT_NO_DATE);
 301         } else {
 302                 label = "Via";
 303                 me = git_committer_info(IDENT_NO_DATE);
 304         }
 305
 306         if (!them->nr ||
 307             (them->nr == 1 &&
 308              me &&
 309              skip_prefix(me, them->items->string, &me) &&
 310              starts_with(me, " <")))
 311                 return;
 312         strbuf_addf(out, "\n%c %s ", comment_line_char, label);
 313         add_people_count(out, them);
 314 }
 315
 316 static void add_people_info(struct strbuf *out,
 317                             struct string_list *authors,
 318                             struct string_list *committers)
 319 {
 320         QSORT(authors->items, authors->nr,
 321               cmp_string_list_util_as_integral);
 322         QSORT(committers->items, committers->nr,
 323               cmp_string_list_util_as_integral);
 324
 325         credit_people(out, authors, 'a');
 326         credit_people(out, committers, 'c');
 327 }
 328
 329 static void shortlog(const char *name,
 330                      struct origin_data *origin_data,
 331                      struct commit *head,
 332                      struct rev_info *rev,
 333                      struct fmt_merge_msg_opts *opts,
 334                      struct strbuf *out)
 335 {
 336         int i, count = 0;
 337         struct commit *commit;
 338         struct object *branch;
 339         struct string_list subjects = STRING_LIST_INIT_DUP;
 340         struct string_list authors = STRING_LIST_INIT_DUP;
 341         struct string_list committers = STRING_LIST_INIT_DUP;
 342         int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 343         struct strbuf sb = STRBUF_INIT;
 344         const struct object_id *oid = &origin_data->oid;
 345         int limit = opts->shortlog_len;
 346
 347         branch = deref_tag(the_repository, parse_object(the_repository, oid),
 348                            oid_to_hex(oid),
 349                            GIT_SHA1_HEXSZ);
 350         if (!branch || branch->type != OBJ_COMMIT)
 351                 return;
 352
 353         setup_revisions(0, NULL, rev, NULL);
 354         add_pending_object(rev, branch, name);
 355         add_pending_object(rev, &head->object, "^HEAD");
 356         head->object.flags |= UNINTERESTING;
 357         if (prepare_revision_walk(rev))
 358                 die("revision walk setup failed");
 359         while ((commit = get_revision(rev)) != NULL) {
 360                 struct pretty_print_context ctx = {0};
 361
 362                 if (commit->parents && commit->parents->next) {
 363                         /* do not list a merge but count committer */
 364                         if (opts->credit_people)
 365                                 record_person('c', &committers, commit);
 366                         continue;
 367                 }
 368                 if (!count && opts->credit_people)
 369                         /* the 'tip' committer */
 370                         record_person('c', &committers, commit);
 371                 if (opts->credit_people)
 372                         record_person('a', &authors, commit);
 373                 count++;
 374                 if (subjects.nr > limit)
 375                         continue;
 376
 377                 format_commit_message(commit, "%s", &sb, &ctx);
 378                 strbuf_ltrim(&sb);
 379
 380                 if (!sb.len)
 381                         string_list_append(&subjects,
 382                                            oid_to_hex(&commit->object.oid));
 383                 else
 384                         string_list_append_nodup(&subjects,
 385                                                  strbuf_detach(&sb, NULL));
 386         }
 387
 388         if (opts->credit_people)
 389                 add_people_info(out, &authors, &committers);
 390         if (count > limit)
 391                 strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
 392         else
 393                 strbuf_addf(out, "\n* %s:\n", name);
 394
 395         if (origin_data->is_local_branch && use_branch_desc)
 396                 add_branch_desc(out, name);
 397
 398         for (i = 0; i < subjects.nr; i++)
 399                 if (i >= limit)
 400                         strbuf_addstr(out, "  ...\n");
 401                 else
 402                         strbuf_addf(out, "  %s\n", subjects.items[i].string);
 403
 404         clear_commit_marks((struct commit *)branch, flags);
 405         clear_commit_marks(head, flags);
 406         free_commit_list(rev->commits);
 407         rev->commits = NULL;
 408         rev->pending.nr = 0;
 409
 410         string_list_clear(&authors, 0);
 411         string_list_clear(&committers, 0);
 412         string_list_clear(&subjects, 0);
 413 }
 414
 415 static void fmt_merge_msg_title(struct strbuf *out,
 416                                 const char *current_branch)
 417 {
 418         int i = 0;
 419         char *sep = "";
 420
 421         strbuf_addstr(out, "Merge ");
 422         for (i = 0; i < srcs.nr; i++) {
 423                 struct src_data *src_data = srcs.items[i].util;
 424                 const char *subsep = "";
 425
 426                 strbuf_addstr(out, sep);
 427                 sep = "; ";
 428
 429                 if (src_data->head_status == 1) {
 430                         strbuf_addstr(out, srcs.items[i].string);
 431                         continue;
 432                 }
 433                 if (src_data->head_status == 3) {
 434                         subsep = ", ";
 435                         strbuf_addstr(out, "HEAD");
 436                 }
 437                 if (src_data->branch.nr) {
 438                         strbuf_addstr(out, subsep);
 439                         subsep = ", ";
 440                         print_joined("branch ", "branches ", &src_data->branch,
 441                                         out);
 442                 }
 443                 if (src_data->r_branch.nr) {
 444                         strbuf_addstr(out, subsep);
 445                         subsep = ", ";
 446                         print_joined("remote-tracking branch ", "remote-tracking branches ",
 447                                         &src_data->r_branch, out);
 448                 }
 449                 if (src_data->tag.nr) {
 450                         strbuf_addstr(out, subsep);
 451                         subsep = ", ";
 452                         print_joined("tag ", "tags ", &src_data->tag, out);
 453                 }
 454                 if (src_data->generic.nr) {
 455                         strbuf_addstr(out, subsep);
 456                         print_joined("commit ", "commits ", &src_data->generic,
 457                                         out);
 458                 }
 459                 if (strcmp(".", srcs.items[i].string))
 460                         strbuf_addf(out, " of %s", srcs.items[i].string);
 461         }
 462
 463         if (!strcmp("master", current_branch))
 464                 strbuf_addch(out, '\n');
 465         else
 466                 strbuf_addf(out, " into %s\n", current_branch);
 467 }
 468
 469 static void fmt_tag_signature(struct strbuf *tagbuf,
 470                               struct strbuf *sig,
 471                               const char *buf,
 472                               unsigned long len)
 473 {
 474         const char *tag_body = strstr(buf, "\n\n");
 475         if (tag_body) {
 476                 tag_body += 2;
 477                 strbuf_add(tagbuf, tag_body, buf + len - tag_body);
 478         }
 479         strbuf_complete_line(tagbuf);
 480         if (sig->len) {
 481                 strbuf_addch(tagbuf, '\n');
 482                 strbuf_add_commented_lines(tagbuf, sig->buf, sig->len);
 483         }
 484 }
 485
 486 static void fmt_merge_msg_sigs(struct strbuf *out)
 487 {
 488         int i, tag_number = 0, first_tag = 0;
 489         struct strbuf tagbuf = STRBUF_INIT;
 490
 491         for (i = 0; i < origins.nr; i++) {
 492                 struct object_id *oid = origins.items[i].util;
 493                 enum object_type type;
 494                 unsigned long size, len;
 495                 char *buf = read_object_file(oid, &type, &size);
 496                 struct strbuf sig = STRBUF_INIT;
 497
 498                 if (!buf || type != OBJ_TAG)
 499                         goto next;
 500                 len = parse_signature(buf, size);
 501
 502                 if (size == len)
 503                         ; /* merely annotated */
 504                 else if (verify_signed_buffer(buf, len, buf + len, size - len, &sig, NULL)) {
 505                         if (!sig.len)
 506                                 strbuf_addstr(&sig, "gpg verification failed.\n");
 507                 }
 508
 509                 if (!tag_number++) {
 510                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 511                         first_tag = i;
 512                 } else {
 513                         if (tag_number == 2) {
 514                                 struct strbuf tagline = STRBUF_INIT;
 515                                 strbuf_addch(&tagline, '\n');
 516                                 strbuf_add_commented_lines(&tagline,
 517                                                 origins.items[first_tag].string,
 518                                                 strlen(origins.items[first_tag].string));
 519                                 strbuf_insert(&tagbuf, 0, tagline.buf,
 520                                               tagline.len);
 521                                 strbuf_release(&tagline);
 522                         }
 523                         strbuf_addch(&tagbuf, '\n');
 524                         strbuf_add_commented_lines(&tagbuf,
 525                                         origins.items[i].string,
 526                                         strlen(origins.items[i].string));
 527                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 528                 }
 529                 strbuf_release(&sig);
 530         next:
 531                 free(buf);
 532         }
 533         if (tagbuf.len) {
 534                 strbuf_addch(out, '\n');
 535                 strbuf_addbuf(out, &tagbuf);
 536         }
 537         strbuf_release(&tagbuf);
 538 }
 539
 540 static void find_merge_parents(struct merge_parents *result,
 541                                struct strbuf *in, struct object_id *head)
 542 {
 543         struct commit_list *parents;
 544         struct commit *head_commit;
 545         int pos = 0, i, j;
 546
 547         parents = NULL;
 548         while (pos < in->len) {
 549                 int len;
 550                 char *p = in->buf + pos;
 551                 char *newline = strchr(p, '\n');
 552                 struct object_id oid;
 553                 struct commit *parent;
 554                 struct object *obj;
 555
 556                 len = newline ? newline - p : strlen(p);
 557                 pos += len + !!newline;
 558
 559                 if (len < GIT_SHA1_HEXSZ + 3 ||
 560                     get_oid_hex(p, &oid) ||
 561                     p[GIT_SHA1_HEXSZ] != '\t' ||
 562                     p[GIT_SHA1_HEXSZ + 1] != '\t')
 563                         continue; /* skip not-for-merge */
 564                 /*
 565                  * Do not use get_merge_parent() here; we do not have
 566                  * "name" here and we do not want to contaminate its
 567                  * util field yet.
 568                  */
 569                 obj = parse_object(the_repository, &oid);
 570                 parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
 571                 if (!parent)
 572                         continue;
 573                 commit_list_insert(parent, &parents);
 574                 add_merge_parent(result, &obj->oid, &parent->object.oid);
 575         }
 576         head_commit = lookup_commit(the_repository, head);
 577         if (head_commit)
 578                 commit_list_insert(head_commit, &parents);
 579         reduce_heads_replace(&parents);
 580
 581         while (parents) {
 582                 struct commit *cmit = pop_commit(&parents);
 583                 for (i = 0; i < result->nr; i++)
 584                         if (!oidcmp(&result->item[i].commit, &cmit->object.oid))
 585                                 result->item[i].used = 1;
 586         }
 587
 588         for (i = j = 0; i < result->nr; i++) {
 589                 if (result->item[i].used) {
 590                         if (i != j)
 591                                 result->item[j] = result->item[i];
 592                         j++;
 593                 }
 594         }
 595         result->nr = j;
 596 }
 597
 598 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 599                   struct fmt_merge_msg_opts *opts)
 600 {
 601         int i = 0, pos = 0;
 602         struct object_id head_oid;
 603         const char *current_branch;
 604         void *current_branch_to_free;
 605         struct merge_parents merge_parents;
 606
 607         memset(&merge_parents, 0, sizeof(merge_parents));
 608
 609         /* get current branch */
 610         current_branch = current_branch_to_free =
 611                 resolve_refdup("HEAD", RESOLVE_REF_READING, &head_oid, NULL);
 612         if (!current_branch)
 613                 die("No current branch");
 614         if (starts_with(current_branch, "refs/heads/"))
 615                 current_branch += 11;
 616
 617         find_merge_parents(&merge_parents, in, &head_oid);
 618
 619         /* get a line */
 620         while (pos < in->len) {
 621                 int len;
 622                 char *newline, *p = in->buf + pos;
 623
 624                 newline = strchr(p, '\n');
 625                 len = newline ? newline - p : strlen(p);
 626                 pos += len + !!newline;
 627                 i++;
 628                 p[len] = 0;
 629                 if (handle_line(p, &merge_parents))
 630                         die ("Error in line %d: %.*s", i, len, p);
 631         }
 632
 633         if (opts->add_title && srcs.nr)
 634                 fmt_merge_msg_title(out, current_branch);
 635
 636         if (origins.nr)
 637                 fmt_merge_msg_sigs(out);
 638
 639         if (opts->shortlog_len) {
 640                 struct commit *head;
 641                 struct rev_info rev;
 642
 643                 head = lookup_commit_or_die(&head_oid, "HEAD");
 644                 init_revisions(&rev, NULL);
 645                 rev.commit_format = CMIT_FMT_ONELINE;
 646                 rev.ignore_merges = 1;
 647                 rev.limited = 1;
 648
 649                 strbuf_complete_line(out);
 650
 651                 for (i = 0; i < origins.nr; i++)
 652                         shortlog(origins.items[i].string,
 653                                  origins.items[i].util,
 654                                  head, &rev, opts, out);
 655         }
 656
 657         strbuf_complete_line(out);
 658         free(current_branch_to_free);
 659         free(merge_parents.item);
 660         return 0;
 661 }
 662
 663 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 664 {
 665         const char *inpath = NULL;
 666         const char *message = NULL;
 667         int shortlog_len = -1;
 668         struct option options[] = {
 669                 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
 670                   N_("populate log with at most <n> entries from shortlog"),
 671                   PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
 672                 { OPTION_INTEGER, 0, "summary", &shortlog_len, N_("n"),
 673                   N_("alias for --log (deprecated)"),
 674                   PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
 675                   DEFAULT_MERGE_LOG_LEN },
 676                 OPT_STRING('m', "message", &message, N_("text"),
 677                         N_("use <text> as start of message")),
 678                 OPT_FILENAME('F', "file", &inpath, N_("file to read from")),
 679                 OPT_END()
 680         };
 681
 682         FILE *in = stdin;
 683         struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
 684         int ret;
 685         struct fmt_merge_msg_opts opts;
 686
 687         git_config(fmt_merge_msg_config, NULL);
 688         argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
 689                              0);
 690         if (argc > 0)
 691                 usage_with_options(fmt_merge_msg_usage, options);
 692         if (shortlog_len < 0)
 693                 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
 694
 695         if (inpath && strcmp(inpath, "-")) {
 696                 in = fopen(inpath, "r");
 697                 if (!in)
 698                         die_errno("cannot open '%s'", inpath);
 699         }
 700
 701         if (strbuf_read(&input, fileno(in), 0) < 0)
 702                 die_errno("could not read input file");
 703
 704         if (message)
 705                 strbuf_addstr(&output, message);
 706
 707         memset(&opts, 0, sizeof(opts));
 708         opts.add_title = !message;
 709         opts.credit_people = 1;
 710         opts.shortlog_len = shortlog_len;
 711
 712         ret = fmt_merge_msg(&input, &output, &opts);
 713         if (ret)
 714                 return ret;
 715         write_in_full(STDOUT_FILENO, output.buf, output.len);
 716         return 0;
 717 }