git.oblomov.eu Git - git/blob - builtin/fmt-merge-msg.c

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "config.h"
   4 #include "refs.h"
   5 #include "commit.h"
   6 #include "diff.h"
   7 #include "revision.h"
   8 #include "tag.h"
   9 #include "string-list.h"
  10 #include "branch.h"
  11 #include "fmt-merge-msg.h"
  12 #include "gpg-interface.h"
  13
  14 static const char * const fmt_merge_msg_usage[] = {
  15         N_("git fmt-merge-msg [-m <message>] [--log[=<n>] | --no-log] [--file <file>]"),
  16         NULL
  17 };
  18
  19 static int use_branch_desc;
  20
  21 int fmt_merge_msg_config(const char *key, const char *value, void *cb)
  22 {
  23         if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
  24                 int is_bool;
  25                 merge_log_config = git_config_bool_or_int(key, value, &is_bool);
  26                 if (!is_bool && merge_log_config < 0)
  27                         return error("%s: negative length %s", key, value);
  28                 if (is_bool && merge_log_config)
  29                         merge_log_config = DEFAULT_MERGE_LOG_LEN;
  30         } else if (!strcmp(key, "merge.branchdesc")) {
  31                 use_branch_desc = git_config_bool(key, value);
  32         } else {
  33                 return git_default_config(key, value, cb);
  34         }
  35         return 0;
  36 }
  37
  38 /* merge data per repository where the merged tips came from */
  39 struct src_data {
  40         struct string_list branch, tag, r_branch, generic;
  41         int head_status;
  42 };
  43
  44 struct origin_data {
  45         struct object_id oid;
  46         unsigned is_local_branch:1;
  47 };
  48
  49 static void init_src_data(struct src_data *data)
  50 {
  51         data->branch.strdup_strings = 1;
  52         data->tag.strdup_strings = 1;
  53         data->r_branch.strdup_strings = 1;
  54         data->generic.strdup_strings = 1;
  55 }
  56
  57 static struct string_list srcs = STRING_LIST_INIT_DUP;
  58 static struct string_list origins = STRING_LIST_INIT_DUP;
  59
  60 struct merge_parents {
  61         int alloc, nr;
  62         struct merge_parent {
  63                 struct object_id given;
  64                 struct object_id commit;
  65                 unsigned char used;
  66         } *item;
  67 };
  68
  69 /*
  70  * I know, I know, this is inefficient, but you won't be pulling and merging
  71  * hundreds of heads at a time anyway.
  72  */
  73 static struct merge_parent *find_merge_parent(struct merge_parents *table,
  74                                               struct object_id *given,
  75                                               struct object_id *commit)
  76 {
  77         int i;
  78         for (i = 0; i < table->nr; i++) {
  79                 if (given && oidcmp(&table->item[i].given, given))
  80                         continue;
  81                 if (commit && oidcmp(&table->item[i].commit, commit))
  82                         continue;
  83                 return &table->item[i];
  84         }
  85         return NULL;
  86 }
  87
  88 static void add_merge_parent(struct merge_parents *table,
  89                              struct object_id *given,
  90                              struct object_id *commit)
  91 {
  92         if (table->nr && find_merge_parent(table, given, commit))
  93                 return;
  94         ALLOC_GROW(table->item, table->nr + 1, table->alloc);
  95         oidcpy(&table->item[table->nr].given, given);
  96         oidcpy(&table->item[table->nr].commit, commit);
  97         table->item[table->nr].used = 0;
  98         table->nr++;
  99 }
 100
 101 static int handle_line(char *line, struct merge_parents *merge_parents)
 102 {
 103         int i, len = strlen(line);
 104         struct origin_data *origin_data;
 105         char *src;
 106         const char *origin;
 107         struct src_data *src_data;
 108         struct string_list_item *item;
 109         int pulling_head = 0;
 110         struct object_id oid;
 111
 112         if (len < GIT_SHA1_HEXSZ + 3 || line[GIT_SHA1_HEXSZ] != '\t')
 113                 return 1;
 114
 115         if (starts_with(line + GIT_SHA1_HEXSZ + 1, "not-for-merge"))
 116                 return 0;
 117
 118         if (line[GIT_SHA1_HEXSZ + 1] != '\t')
 119                 return 2;
 120
 121         i = get_oid_hex(line, &oid);
 122         if (i)
 123                 return 3;
 124
 125         if (!find_merge_parent(merge_parents, &oid, NULL))
 126                 return 0; /* subsumed by other parents */
 127
 128         origin_data = xcalloc(1, sizeof(struct origin_data));
 129         oidcpy(&origin_data->oid, &oid);
 130
 131         if (line[len - 1] == '\n')
 132                 line[len - 1] = 0;
 133         line += GIT_SHA1_HEXSZ + 2;
 134
 135         /*
 136          * At this point, line points at the beginning of comment e.g.
 137          * "branch 'frotz' of git://that/repository.git".
 138          * Find the repository name and point it with src.
 139          */
 140         src = strstr(line, " of ");
 141         if (src) {
 142                 *src = 0;
 143                 src += 4;
 144                 pulling_head = 0;
 145         } else {
 146                 src = line;
 147                 pulling_head = 1;
 148         }
 149
 150         item = unsorted_string_list_lookup(&srcs, src);
 151         if (!item) {
 152                 item = string_list_append(&srcs, src);
 153                 item->util = xcalloc(1, sizeof(struct src_data));
 154                 init_src_data(item->util);
 155         }
 156         src_data = item->util;
 157
 158         if (pulling_head) {
 159                 origin = src;
 160                 src_data->head_status |= 1;
 161         } else if (starts_with(line, "branch ")) {
 162                 origin_data->is_local_branch = 1;
 163                 origin = line + 7;
 164                 string_list_append(&src_data->branch, origin);
 165                 src_data->head_status |= 2;
 166         } else if (starts_with(line, "tag ")) {
 167                 origin = line;
 168                 string_list_append(&src_data->tag, origin + 4);
 169                 src_data->head_status |= 2;
 170         } else if (skip_prefix(line, "remote-tracking branch ", &origin)) {
 171                 string_list_append(&src_data->r_branch, origin);
 172                 src_data->head_status |= 2;
 173         } else {
 174                 origin = src;
 175                 string_list_append(&src_data->generic, line);
 176                 src_data->head_status |= 2;
 177         }
 178
 179         if (!strcmp(".", src) || !strcmp(src, origin)) {
 180                 int len = strlen(origin);
 181                 if (origin[0] == '\'' && origin[len - 1] == '\'')
 182                         origin = xmemdupz(origin + 1, len - 2);
 183         } else
 184                 origin = xstrfmt("%s of %s", origin, src);
 185         if (strcmp(".", src))
 186                 origin_data->is_local_branch = 0;
 187         string_list_append(&origins, origin)->util = origin_data;
 188         return 0;
 189 }
 190
 191 static void print_joined(const char *singular, const char *plural,
 192                 struct string_list *list, struct strbuf *out)
 193 {
 194         if (list->nr == 0)
 195                 return;
 196         if (list->nr == 1) {
 197                 strbuf_addf(out, "%s%s", singular, list->items[0].string);
 198         } else {
 199                 int i;
 200                 strbuf_addstr(out, plural);
 201                 for (i = 0; i < list->nr - 1; i++)
 202                         strbuf_addf(out, "%s%s", i > 0 ? ", " : "",
 203                                     list->items[i].string);
 204                 strbuf_addf(out, " and %s", list->items[list->nr - 1].string);
 205         }
 206 }
 207
 208 static void add_branch_desc(struct strbuf *out, const char *name)
 209 {
 210         struct strbuf desc = STRBUF_INIT;
 211
 212         if (!read_branch_desc(&desc, name)) {
 213                 const char *bp = desc.buf;
 214                 while (*bp) {
 215                         const char *ep = strchrnul(bp, '\n');
 216                         if (*ep)
 217                                 ep++;
 218                         strbuf_addf(out, "  : %.*s", (int)(ep - bp), bp);
 219                         bp = ep;
 220                 }
 221                 strbuf_complete_line(out);
 222         }
 223         strbuf_release(&desc);
 224 }
 225
 226 #define util_as_integral(elem) ((intptr_t)((elem)->util))
 227
 228 static void record_person_from_buf(int which, struct string_list *people,
 229                                    const char *buffer)
 230 {
 231         char *name_buf, *name, *name_end;
 232         struct string_list_item *elem;
 233         const char *field;
 234
 235         field = (which == 'a') ? "\nauthor " : "\ncommitter ";
 236         name = strstr(buffer, field);
 237         if (!name)
 238                 return;
 239         name += strlen(field);
 240         name_end = strchrnul(name, '<');
 241         if (*name_end)
 242                 name_end--;
 243         while (isspace(*name_end) && name <= name_end)
 244                 name_end--;
 245         if (name_end < name)
 246                 return;
 247         name_buf = xmemdupz(name, name_end - name + 1);
 248
 249         elem = string_list_lookup(people, name_buf);
 250         if (!elem) {
 251                 elem = string_list_insert(people, name_buf);
 252                 elem->util = (void *)0;
 253         }
 254         elem->util = (void*)(util_as_integral(elem) + 1);
 255         free(name_buf);
 256 }
 257
 258
 259 static void record_person(int which, struct string_list *people,
 260                           struct commit *commit)
 261 {
 262         const char *buffer = get_commit_buffer(commit, NULL);
 263         record_person_from_buf(which, people, buffer);
 264         unuse_commit_buffer(commit, buffer);
 265 }
 266
 267 static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
 268 {
 269         const struct string_list_item *a = a_, *b = b_;
 270         return util_as_integral(b) - util_as_integral(a);
 271 }
 272
 273 static void add_people_count(struct strbuf *out, struct string_list *people)
 274 {
 275         if (people->nr == 1)
 276                 strbuf_addstr(out, people->items[0].string);
 277         else if (people->nr == 2)
 278                 strbuf_addf(out, "%s (%d) and %s (%d)",
 279                             people->items[0].string,
 280                             (int)util_as_integral(&people->items[0]),
 281                             people->items[1].string,
 282                             (int)util_as_integral(&people->items[1]));
 283         else if (people->nr)
 284                 strbuf_addf(out, "%s (%d) and others",
 285                             people->items[0].string,
 286                             (int)util_as_integral(&people->items[0]));
 287 }
 288
 289 static void credit_people(struct strbuf *out,
 290                           struct string_list *them,
 291                           int kind)
 292 {
 293         const char *label;
 294         const char *me;
 295
 296         if (kind == 'a') {
 297                 label = "By";
 298                 me = git_author_info(IDENT_NO_DATE);
 299         } else {
 300                 label = "Via";
 301                 me = git_committer_info(IDENT_NO_DATE);
 302         }
 303
 304         if (!them->nr ||
 305             (them->nr == 1 &&
 306              me &&
 307              skip_prefix(me, them->items->string, &me) &&
 308              starts_with(me, " <")))
 309                 return;
 310         strbuf_addf(out, "\n%c %s ", comment_line_char, label);
 311         add_people_count(out, them);
 312 }
 313
 314 static void add_people_info(struct strbuf *out,
 315                             struct string_list *authors,
 316                             struct string_list *committers)
 317 {
 318         QSORT(authors->items, authors->nr,
 319               cmp_string_list_util_as_integral);
 320         QSORT(committers->items, committers->nr,
 321               cmp_string_list_util_as_integral);
 322
 323         credit_people(out, authors, 'a');
 324         credit_people(out, committers, 'c');
 325 }
 326
 327 static void shortlog(const char *name,
 328                      struct origin_data *origin_data,
 329                      struct commit *head,
 330                      struct rev_info *rev,
 331                      struct fmt_merge_msg_opts *opts,
 332                      struct strbuf *out)
 333 {
 334         int i, count = 0;
 335         struct commit *commit;
 336         struct object *branch;
 337         struct string_list subjects = STRING_LIST_INIT_DUP;
 338         struct string_list authors = STRING_LIST_INIT_DUP;
 339         struct string_list committers = STRING_LIST_INIT_DUP;
 340         int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 341         struct strbuf sb = STRBUF_INIT;
 342         const struct object_id *oid = &origin_data->oid;
 343         int limit = opts->shortlog_len;
 344
 345         branch = deref_tag(parse_object(oid), oid_to_hex(oid), GIT_SHA1_HEXSZ);
 346         if (!branch || branch->type != OBJ_COMMIT)
 347                 return;
 348
 349         setup_revisions(0, NULL, rev, NULL);
 350         add_pending_object(rev, branch, name);
 351         add_pending_object(rev, &head->object, "^HEAD");
 352         head->object.flags |= UNINTERESTING;
 353         if (prepare_revision_walk(rev))
 354                 die("revision walk setup failed");
 355         while ((commit = get_revision(rev)) != NULL) {
 356                 struct pretty_print_context ctx = {0};
 357
 358                 if (commit->parents && commit->parents->next) {
 359                         /* do not list a merge but count committer */
 360                         if (opts->credit_people)
 361                                 record_person('c', &committers, commit);
 362                         continue;
 363                 }
 364                 if (!count && opts->credit_people)
 365                         /* the 'tip' committer */
 366                         record_person('c', &committers, commit);
 367                 if (opts->credit_people)
 368                         record_person('a', &authors, commit);
 369                 count++;
 370                 if (subjects.nr > limit)
 371                         continue;
 372
 373                 format_commit_message(commit, "%s", &sb, &ctx);
 374                 strbuf_ltrim(&sb);
 375
 376                 if (!sb.len)
 377                         string_list_append(&subjects,
 378                                            oid_to_hex(&commit->object.oid));
 379                 else
 380                         string_list_append(&subjects, strbuf_detach(&sb, NULL));
 381         }
 382
 383         if (opts->credit_people)
 384                 add_people_info(out, &authors, &committers);
 385         if (count > limit)
 386                 strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
 387         else
 388                 strbuf_addf(out, "\n* %s:\n", name);
 389
 390         if (origin_data->is_local_branch && use_branch_desc)
 391                 add_branch_desc(out, name);
 392
 393         for (i = 0; i < subjects.nr; i++)
 394                 if (i >= limit)
 395                         strbuf_addstr(out, "  ...\n");
 396                 else
 397                         strbuf_addf(out, "  %s\n", subjects.items[i].string);
 398
 399         clear_commit_marks((struct commit *)branch, flags);
 400         clear_commit_marks(head, flags);
 401         free_commit_list(rev->commits);
 402         rev->commits = NULL;
 403         rev->pending.nr = 0;
 404
 405         string_list_clear(&authors, 0);
 406         string_list_clear(&committers, 0);
 407         string_list_clear(&subjects, 0);
 408 }
 409
 410 static void fmt_merge_msg_title(struct strbuf *out,
 411                                 const char *current_branch)
 412 {
 413         int i = 0;
 414         char *sep = "";
 415
 416         strbuf_addstr(out, "Merge ");
 417         for (i = 0; i < srcs.nr; i++) {
 418                 struct src_data *src_data = srcs.items[i].util;
 419                 const char *subsep = "";
 420
 421                 strbuf_addstr(out, sep);
 422                 sep = "; ";
 423
 424                 if (src_data->head_status == 1) {
 425                         strbuf_addstr(out, srcs.items[i].string);
 426                         continue;
 427                 }
 428                 if (src_data->head_status == 3) {
 429                         subsep = ", ";
 430                         strbuf_addstr(out, "HEAD");
 431                 }
 432                 if (src_data->branch.nr) {
 433                         strbuf_addstr(out, subsep);
 434                         subsep = ", ";
 435                         print_joined("branch ", "branches ", &src_data->branch,
 436                                         out);
 437                 }
 438                 if (src_data->r_branch.nr) {
 439                         strbuf_addstr(out, subsep);
 440                         subsep = ", ";
 441                         print_joined("remote-tracking branch ", "remote-tracking branches ",
 442                                         &src_data->r_branch, out);
 443                 }
 444                 if (src_data->tag.nr) {
 445                         strbuf_addstr(out, subsep);
 446                         subsep = ", ";
 447                         print_joined("tag ", "tags ", &src_data->tag, out);
 448                 }
 449                 if (src_data->generic.nr) {
 450                         strbuf_addstr(out, subsep);
 451                         print_joined("commit ", "commits ", &src_data->generic,
 452                                         out);
 453                 }
 454                 if (strcmp(".", srcs.items[i].string))
 455                         strbuf_addf(out, " of %s", srcs.items[i].string);
 456         }
 457
 458         if (!strcmp("master", current_branch))
 459                 strbuf_addch(out, '\n');
 460         else
 461                 strbuf_addf(out, " into %s\n", current_branch);
 462 }
 463
 464 static void fmt_tag_signature(struct strbuf *tagbuf,
 465                               struct strbuf *sig,
 466                               const char *buf,
 467                               unsigned long len)
 468 {
 469         const char *tag_body = strstr(buf, "\n\n");
 470         if (tag_body) {
 471                 tag_body += 2;
 472                 strbuf_add(tagbuf, tag_body, buf + len - tag_body);
 473         }
 474         strbuf_complete_line(tagbuf);
 475         if (sig->len) {
 476                 strbuf_addch(tagbuf, '\n');
 477                 strbuf_add_commented_lines(tagbuf, sig->buf, sig->len);
 478         }
 479 }
 480
 481 static void fmt_merge_msg_sigs(struct strbuf *out)
 482 {
 483         int i, tag_number = 0, first_tag = 0;
 484         struct strbuf tagbuf = STRBUF_INIT;
 485
 486         for (i = 0; i < origins.nr; i++) {
 487                 unsigned char *sha1 = origins.items[i].util;
 488                 enum object_type type;
 489                 unsigned long size, len;
 490                 char *buf = read_sha1_file(sha1, &type, &size);
 491                 struct strbuf sig = STRBUF_INIT;
 492
 493                 if (!buf || type != OBJ_TAG)
 494                         goto next;
 495                 len = parse_signature(buf, size);
 496
 497                 if (size == len)
 498                         ; /* merely annotated */
 499                 else if (verify_signed_buffer(buf, len, buf + len, size - len, &sig, NULL)) {
 500                         if (!sig.len)
 501                                 strbuf_addstr(&sig, "gpg verification failed.\n");
 502                 }
 503
 504                 if (!tag_number++) {
 505                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 506                         first_tag = i;
 507                 } else {
 508                         if (tag_number == 2) {
 509                                 struct strbuf tagline = STRBUF_INIT;
 510                                 strbuf_addch(&tagline, '\n');
 511                                 strbuf_add_commented_lines(&tagline,
 512                                                 origins.items[first_tag].string,
 513                                                 strlen(origins.items[first_tag].string));
 514                                 strbuf_insert(&tagbuf, 0, tagline.buf,
 515                                               tagline.len);
 516                                 strbuf_release(&tagline);
 517                         }
 518                         strbuf_addch(&tagbuf, '\n');
 519                         strbuf_add_commented_lines(&tagbuf,
 520                                         origins.items[i].string,
 521                                         strlen(origins.items[i].string));
 522                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 523                 }
 524                 strbuf_release(&sig);
 525         next:
 526                 free(buf);
 527         }
 528         if (tagbuf.len) {
 529                 strbuf_addch(out, '\n');
 530                 strbuf_addbuf(out, &tagbuf);
 531         }
 532         strbuf_release(&tagbuf);
 533 }
 534
 535 static void find_merge_parents(struct merge_parents *result,
 536                                struct strbuf *in, struct object_id *head)
 537 {
 538         struct commit_list *parents;
 539         struct commit *head_commit;
 540         int pos = 0, i, j;
 541
 542         parents = NULL;
 543         while (pos < in->len) {
 544                 int len;
 545                 char *p = in->buf + pos;
 546                 char *newline = strchr(p, '\n');
 547                 struct object_id oid;
 548                 struct commit *parent;
 549                 struct object *obj;
 550
 551                 len = newline ? newline - p : strlen(p);
 552                 pos += len + !!newline;
 553
 554                 if (len < GIT_SHA1_HEXSZ + 3 ||
 555                     get_oid_hex(p, &oid) ||
 556                     p[GIT_SHA1_HEXSZ] != '\t' ||
 557                     p[GIT_SHA1_HEXSZ + 1] != '\t')
 558                         continue; /* skip not-for-merge */
 559                 /*
 560                  * Do not use get_merge_parent() here; we do not have
 561                  * "name" here and we do not want to contaminate its
 562                  * util field yet.
 563                  */
 564                 obj = parse_object(&oid);
 565                 parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
 566                 if (!parent)
 567                         continue;
 568                 commit_list_insert(parent, &parents);
 569                 add_merge_parent(result, &obj->oid, &parent->object.oid);
 570         }
 571         head_commit = lookup_commit(head);
 572         if (head_commit)
 573                 commit_list_insert(head_commit, &parents);
 574         reduce_heads_replace(&parents);
 575
 576         while (parents) {
 577                 struct commit *cmit = pop_commit(&parents);
 578                 for (i = 0; i < result->nr; i++)
 579                         if (!oidcmp(&result->item[i].commit, &cmit->object.oid))
 580                                 result->item[i].used = 1;
 581         }
 582
 583         for (i = j = 0; i < result->nr; i++) {
 584                 if (result->item[i].used) {
 585                         if (i != j)
 586                                 result->item[j] = result->item[i];
 587                         j++;
 588                 }
 589         }
 590         result->nr = j;
 591 }
 592
 593 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 594                   struct fmt_merge_msg_opts *opts)
 595 {
 596         int i = 0, pos = 0;
 597         struct object_id head_oid;
 598         const char *current_branch;
 599         void *current_branch_to_free;
 600         struct merge_parents merge_parents;
 601
 602         memset(&merge_parents, 0, sizeof(merge_parents));
 603
 604         /* get current branch */
 605         current_branch = current_branch_to_free =
 606                 resolve_refdup("HEAD", RESOLVE_REF_READING, &head_oid, NULL);
 607         if (!current_branch)
 608                 die("No current branch");
 609         if (starts_with(current_branch, "refs/heads/"))
 610                 current_branch += 11;
 611
 612         find_merge_parents(&merge_parents, in, &head_oid);
 613
 614         /* get a line */
 615         while (pos < in->len) {
 616                 int len;
 617                 char *newline, *p = in->buf + pos;
 618
 619                 newline = strchr(p, '\n');
 620                 len = newline ? newline - p : strlen(p);
 621                 pos += len + !!newline;
 622                 i++;
 623                 p[len] = 0;
 624                 if (handle_line(p, &merge_parents))
 625                         die ("Error in line %d: %.*s", i, len, p);
 626         }
 627
 628         if (opts->add_title && srcs.nr)
 629                 fmt_merge_msg_title(out, current_branch);
 630
 631         if (origins.nr)
 632                 fmt_merge_msg_sigs(out);
 633
 634         if (opts->shortlog_len) {
 635                 struct commit *head;
 636                 struct rev_info rev;
 637
 638                 head = lookup_commit_or_die(&head_oid, "HEAD");
 639                 init_revisions(&rev, NULL);
 640                 rev.commit_format = CMIT_FMT_ONELINE;
 641                 rev.ignore_merges = 1;
 642                 rev.limited = 1;
 643
 644                 strbuf_complete_line(out);
 645
 646                 for (i = 0; i < origins.nr; i++)
 647                         shortlog(origins.items[i].string,
 648                                  origins.items[i].util,
 649                                  head, &rev, opts, out);
 650         }
 651
 652         strbuf_complete_line(out);
 653         free(current_branch_to_free);
 654         free(merge_parents.item);
 655         return 0;
 656 }
 657
 658 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 659 {
 660         const char *inpath = NULL;
 661         const char *message = NULL;
 662         int shortlog_len = -1;
 663         struct option options[] = {
 664                 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
 665                   N_("populate log with at most <n> entries from shortlog"),
 666                   PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
 667                 { OPTION_INTEGER, 0, "summary", &shortlog_len, N_("n"),
 668                   N_("alias for --log (deprecated)"),
 669                   PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
 670                   DEFAULT_MERGE_LOG_LEN },
 671                 OPT_STRING('m', "message", &message, N_("text"),
 672                         N_("use <text> as start of message")),
 673                 OPT_FILENAME('F', "file", &inpath, N_("file to read from")),
 674                 OPT_END()
 675         };
 676
 677         FILE *in = stdin;
 678         struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
 679         int ret;
 680         struct fmt_merge_msg_opts opts;
 681
 682         git_config(fmt_merge_msg_config, NULL);
 683         argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
 684                              0);
 685         if (argc > 0)
 686                 usage_with_options(fmt_merge_msg_usage, options);
 687         if (shortlog_len < 0)
 688                 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
 689
 690         if (inpath && strcmp(inpath, "-")) {
 691                 in = fopen(inpath, "r");
 692                 if (!in)
 693                         die_errno("cannot open '%s'", inpath);
 694         }
 695
 696         if (strbuf_read(&input, fileno(in), 0) < 0)
 697                 die_errno("could not read input file");
 698
 699         if (message)
 700                 strbuf_addstr(&output, message);
 701
 702         memset(&opts, 0, sizeof(opts));
 703         opts.add_title = !message;
 704         opts.credit_people = 1;
 705         opts.shortlog_len = shortlog_len;
 706
 707         ret = fmt_merge_msg(&input, &output, &opts);
 708         if (ret)
 709                 return ret;
 710         write_in_full(STDOUT_FILENO, output.buf, output.len);
 711         return 0;
 712 }