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 #include "commit-reach.h"
  16
  17 static const char * const fmt_merge_msg_usage[] = {
  18         N_("git fmt-merge-msg [-m <message>] [--log[=<n>] | --no-log] [--file <file>]"),
  19         NULL
  20 };
  21
  22 static int use_branch_desc;
  23
  24 int fmt_merge_msg_config(const char *key, const char *value, void *cb)
  25 {
  26         if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
  27                 int is_bool;
  28                 merge_log_config = git_config_bool_or_int(key, value, &is_bool);
  29                 if (!is_bool && merge_log_config < 0)
  30                         return error("%s: negative length %s", key, value);
  31                 if (is_bool && merge_log_config)
  32                         merge_log_config = DEFAULT_MERGE_LOG_LEN;
  33         } else if (!strcmp(key, "merge.branchdesc")) {
  34                 use_branch_desc = git_config_bool(key, value);
  35         } else {
  36                 return git_default_config(key, value, cb);
  37         }
  38         return 0;
  39 }
  40
  41 /* merge data per repository where the merged tips came from */
  42 struct src_data {
  43         struct string_list branch, tag, r_branch, generic;
  44         int head_status;
  45 };
  46
  47 struct origin_data {
  48         struct object_id oid;
  49         unsigned is_local_branch:1;
  50 };
  51
  52 static void init_src_data(struct src_data *data)
  53 {
  54         data->branch.strdup_strings = 1;
  55         data->tag.strdup_strings = 1;
  56         data->r_branch.strdup_strings = 1;
  57         data->generic.strdup_strings = 1;
  58 }
  59
  60 static struct string_list srcs = STRING_LIST_INIT_DUP;
  61 static struct string_list origins = STRING_LIST_INIT_DUP;
  62
  63 struct merge_parents {
  64         int alloc, nr;
  65         struct merge_parent {
  66                 struct object_id given;
  67                 struct object_id commit;
  68                 unsigned char used;
  69         } *item;
  70 };
  71
  72 /*
  73  * I know, I know, this is inefficient, but you won't be pulling and merging
  74  * hundreds of heads at a time anyway.
  75  */
  76 static struct merge_parent *find_merge_parent(struct merge_parents *table,
  77                                               struct object_id *given,
  78                                               struct object_id *commit)
  79 {
  80         int i;
  81         for (i = 0; i < table->nr; i++) {
  82                 if (given && !oideq(&table->item[i].given, given))
  83                         continue;
  84                 if (commit && !oideq(&table->item[i].commit, commit))
  85                         continue;
  86                 return &table->item[i];
  87         }
  88         return NULL;
  89 }
  90
  91 static void add_merge_parent(struct merge_parents *table,
  92                              struct object_id *given,
  93                              struct object_id *commit)
  94 {
  95         if (table->nr && find_merge_parent(table, given, commit))
  96                 return;
  97         ALLOC_GROW(table->item, table->nr + 1, table->alloc);
  98         oidcpy(&table->item[table->nr].given, given);
  99         oidcpy(&table->item[table->nr].commit, commit);
 100         table->item[table->nr].used = 0;
 101         table->nr++;
 102 }
 103
 104 static int handle_line(char *line, struct merge_parents *merge_parents)
 105 {
 106         int i, len = strlen(line);
 107         struct origin_data *origin_data;
 108         char *src;
 109         const char *origin, *tag_name;
 110         struct src_data *src_data;
 111         struct string_list_item *item;
 112         int pulling_head = 0;
 113         struct object_id oid;
 114         const unsigned hexsz = the_hash_algo->hexsz;
 115
 116         if (len < hexsz + 3 || line[hexsz] != '\t')
 117                 return 1;
 118
 119         if (starts_with(line + hexsz + 1, "not-for-merge"))
 120                 return 0;
 121
 122         if (line[hexsz + 1] != '\t')
 123                 return 2;
 124
 125         i = get_oid_hex(line, &oid);
 126         if (i)
 127                 return 3;
 128
 129         if (!find_merge_parent(merge_parents, &oid, NULL))
 130                 return 0; /* subsumed by other parents */
 131
 132         origin_data = xcalloc(1, sizeof(struct origin_data));
 133         oidcpy(&origin_data->oid, &oid);
 134
 135         if (line[len - 1] == '\n')
 136                 line[len - 1] = 0;
 137         line += hexsz + 2;
 138
 139         /*
 140          * At this point, line points at the beginning of comment e.g.
 141          * "branch 'frotz' of git://that/repository.git".
 142          * Find the repository name and point it with src.
 143          */
 144         src = strstr(line, " of ");
 145         if (src) {
 146                 *src = 0;
 147                 src += 4;
 148                 pulling_head = 0;
 149         } else {
 150                 src = line;
 151                 pulling_head = 1;
 152         }
 153
 154         item = unsorted_string_list_lookup(&srcs, src);
 155         if (!item) {
 156                 item = string_list_append(&srcs, src);
 157                 item->util = xcalloc(1, sizeof(struct src_data));
 158                 init_src_data(item->util);
 159         }
 160         src_data = item->util;
 161
 162         if (pulling_head) {
 163                 origin = src;
 164                 src_data->head_status |= 1;
 165         } else if (skip_prefix(line, "branch ", &origin)) {
 166                 origin_data->is_local_branch = 1;
 167                 string_list_append(&src_data->branch, origin);
 168                 src_data->head_status |= 2;
 169         } else if (skip_prefix(line, "tag ", &tag_name)) {
 170                 origin = line;
 171                 string_list_append(&src_data->tag, tag_name);
 172                 src_data->head_status |= 2;
 173         } else if (skip_prefix(line, "remote-tracking branch ", &origin)) {
 174                 string_list_append(&src_data->r_branch, origin);
 175                 src_data->head_status |= 2;
 176         } else {
 177                 origin = src;
 178                 string_list_append(&src_data->generic, line);
 179                 src_data->head_status |= 2;
 180         }
 181
 182         if (!strcmp(".", src) || !strcmp(src, origin)) {
 183                 int len = strlen(origin);
 184                 if (origin[0] == '\'' && origin[len - 1] == '\'')
 185                         origin = xmemdupz(origin + 1, len - 2);
 186         } else
 187                 origin = xstrfmt("%s of %s", origin, src);
 188         if (strcmp(".", src))
 189                 origin_data->is_local_branch = 0;
 190         string_list_append(&origins, origin)->util = origin_data;
 191         return 0;
 192 }
 193
 194 static void print_joined(const char *singular, const char *plural,
 195                 struct string_list *list, struct strbuf *out)
 196 {
 197         if (list->nr == 0)
 198                 return;
 199         if (list->nr == 1) {
 200                 strbuf_addf(out, "%s%s", singular, list->items[0].string);
 201         } else {
 202                 int i;
 203                 strbuf_addstr(out, plural);
 204                 for (i = 0; i < list->nr - 1; i++)
 205                         strbuf_addf(out, "%s%s", i > 0 ? ", " : "",
 206                                     list->items[i].string);
 207                 strbuf_addf(out, " and %s", list->items[list->nr - 1].string);
 208         }
 209 }
 210
 211 static void add_branch_desc(struct strbuf *out, const char *name)
 212 {
 213         struct strbuf desc = STRBUF_INIT;
 214
 215         if (!read_branch_desc(&desc, name)) {
 216                 const char *bp = desc.buf;
 217                 while (*bp) {
 218                         const char *ep = strchrnul(bp, '\n');
 219                         if (*ep)
 220                                 ep++;
 221                         strbuf_addf(out, "  : %.*s", (int)(ep - bp), bp);
 222                         bp = ep;
 223                 }
 224                 strbuf_complete_line(out);
 225         }
 226         strbuf_release(&desc);
 227 }
 228
 229 #define util_as_integral(elem) ((intptr_t)((elem)->util))
 230
 231 static void record_person_from_buf(int which, struct string_list *people,
 232                                    const char *buffer)
 233 {
 234         char *name_buf, *name, *name_end;
 235         struct string_list_item *elem;
 236         const char *field;
 237
 238         field = (which == 'a') ? "\nauthor " : "\ncommitter ";
 239         name = strstr(buffer, field);
 240         if (!name)
 241                 return;
 242         name += strlen(field);
 243         name_end = strchrnul(name, '<');
 244         if (*name_end)
 245                 name_end--;
 246         while (isspace(*name_end) && name <= name_end)
 247                 name_end--;
 248         if (name_end < name)
 249                 return;
 250         name_buf = xmemdupz(name, name_end - name + 1);
 251
 252         elem = string_list_lookup(people, name_buf);
 253         if (!elem) {
 254                 elem = string_list_insert(people, name_buf);
 255                 elem->util = (void *)0;
 256         }
 257         elem->util = (void*)(util_as_integral(elem) + 1);
 258         free(name_buf);
 259 }
 260
 261
 262 static void record_person(int which, struct string_list *people,
 263                           struct commit *commit)
 264 {
 265         const char *buffer = get_commit_buffer(commit, NULL);
 266         record_person_from_buf(which, people, buffer);
 267         unuse_commit_buffer(commit, buffer);
 268 }
 269
 270 static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
 271 {
 272         const struct string_list_item *a = a_, *b = b_;
 273         return util_as_integral(b) - util_as_integral(a);
 274 }
 275
 276 static void add_people_count(struct strbuf *out, struct string_list *people)
 277 {
 278         if (people->nr == 1)
 279                 strbuf_addstr(out, people->items[0].string);
 280         else if (people->nr == 2)
 281                 strbuf_addf(out, "%s (%d) and %s (%d)",
 282                             people->items[0].string,
 283                             (int)util_as_integral(&people->items[0]),
 284                             people->items[1].string,
 285                             (int)util_as_integral(&people->items[1]));
 286         else if (people->nr)
 287                 strbuf_addf(out, "%s (%d) and others",
 288                             people->items[0].string,
 289                             (int)util_as_integral(&people->items[0]));
 290 }
 291
 292 static void credit_people(struct strbuf *out,
 293                           struct string_list *them,
 294                           int kind)
 295 {
 296         const char *label;
 297         const char *me;
 298
 299         if (kind == 'a') {
 300                 label = "By";
 301                 me = git_author_info(IDENT_NO_DATE);
 302         } else {
 303                 label = "Via";
 304                 me = git_committer_info(IDENT_NO_DATE);
 305         }
 306
 307         if (!them->nr ||
 308             (them->nr == 1 &&
 309              me &&
 310              skip_prefix(me, them->items->string, &me) &&
 311              starts_with(me, " <")))
 312                 return;
 313         strbuf_addf(out, "\n%c %s ", comment_line_char, label);
 314         add_people_count(out, them);
 315 }
 316
 317 static void add_people_info(struct strbuf *out,
 318                             struct string_list *authors,
 319                             struct string_list *committers)
 320 {
 321         QSORT(authors->items, authors->nr,
 322               cmp_string_list_util_as_integral);
 323         QSORT(committers->items, committers->nr,
 324               cmp_string_list_util_as_integral);
 325
 326         credit_people(out, authors, 'a');
 327         credit_people(out, committers, 'c');
 328 }
 329
 330 static void shortlog(const char *name,
 331                      struct origin_data *origin_data,
 332                      struct commit *head,
 333                      struct rev_info *rev,
 334                      struct fmt_merge_msg_opts *opts,
 335                      struct strbuf *out)
 336 {
 337         int i, count = 0;
 338         struct commit *commit;
 339         struct object *branch;
 340         struct string_list subjects = STRING_LIST_INIT_DUP;
 341         struct string_list authors = STRING_LIST_INIT_DUP;
 342         struct string_list committers = STRING_LIST_INIT_DUP;
 343         int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 344         struct strbuf sb = STRBUF_INIT;
 345         const struct object_id *oid = &origin_data->oid;
 346         int limit = opts->shortlog_len;
 347
 348         branch = deref_tag(the_repository, parse_object(the_repository, oid),
 349                            oid_to_hex(oid),
 350                            the_hash_algo->hexsz);
 351         if (!branch || branch->type != OBJ_COMMIT)
 352                 return;
 353
 354         setup_revisions(0, NULL, rev, NULL);
 355         add_pending_object(rev, branch, name);
 356         add_pending_object(rev, &head->object, "^HEAD");
 357         head->object.flags |= UNINTERESTING;
 358         if (prepare_revision_walk(rev))
 359                 die("revision walk setup failed");
 360         while ((commit = get_revision(rev)) != NULL) {
 361                 struct pretty_print_context ctx = {0};
 362
 363                 if (commit->parents && commit->parents->next) {
 364                         /* do not list a merge but count committer */
 365                         if (opts->credit_people)
 366                                 record_person('c', &committers, commit);
 367                         continue;
 368                 }
 369                 if (!count && opts->credit_people)
 370                         /* the 'tip' committer */
 371                         record_person('c', &committers, commit);
 372                 if (opts->credit_people)
 373                         record_person('a', &authors, commit);
 374                 count++;
 375                 if (subjects.nr > limit)
 376                         continue;
 377
 378                 format_commit_message(commit, "%s", &sb, &ctx);
 379                 strbuf_ltrim(&sb);
 380
 381                 if (!sb.len)
 382                         string_list_append(&subjects,
 383                                            oid_to_hex(&commit->object.oid));
 384                 else
 385                         string_list_append_nodup(&subjects,
 386                                                  strbuf_detach(&sb, NULL));
 387         }
 388
 389         if (opts->credit_people)
 390                 add_people_info(out, &authors, &committers);
 391         if (count > limit)
 392                 strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
 393         else
 394                 strbuf_addf(out, "\n* %s:\n", name);
 395
 396         if (origin_data->is_local_branch && use_branch_desc)
 397                 add_branch_desc(out, name);
 398
 399         for (i = 0; i < subjects.nr; i++)
 400                 if (i >= limit)
 401                         strbuf_addstr(out, "  ...\n");
 402                 else
 403                         strbuf_addf(out, "  %s\n", subjects.items[i].string);
 404
 405         clear_commit_marks((struct commit *)branch, flags);
 406         clear_commit_marks(head, flags);
 407         free_commit_list(rev->commits);
 408         rev->commits = NULL;
 409         rev->pending.nr = 0;
 410
 411         string_list_clear(&authors, 0);
 412         string_list_clear(&committers, 0);
 413         string_list_clear(&subjects, 0);
 414 }
 415
 416 static void fmt_merge_msg_title(struct strbuf *out,
 417                                 const char *current_branch)
 418 {
 419         int i = 0;
 420         char *sep = "";
 421
 422         strbuf_addstr(out, "Merge ");
 423         for (i = 0; i < srcs.nr; i++) {
 424                 struct src_data *src_data = srcs.items[i].util;
 425                 const char *subsep = "";
 426
 427                 strbuf_addstr(out, sep);
 428                 sep = "; ";
 429
 430                 if (src_data->head_status == 1) {
 431                         strbuf_addstr(out, srcs.items[i].string);
 432                         continue;
 433                 }
 434                 if (src_data->head_status == 3) {
 435                         subsep = ", ";
 436                         strbuf_addstr(out, "HEAD");
 437                 }
 438                 if (src_data->branch.nr) {
 439                         strbuf_addstr(out, subsep);
 440                         subsep = ", ";
 441                         print_joined("branch ", "branches ", &src_data->branch,
 442                                         out);
 443                 }
 444                 if (src_data->r_branch.nr) {
 445                         strbuf_addstr(out, subsep);
 446                         subsep = ", ";
 447                         print_joined("remote-tracking branch ", "remote-tracking branches ",
 448                                         &src_data->r_branch, out);
 449                 }
 450                 if (src_data->tag.nr) {
 451                         strbuf_addstr(out, subsep);
 452                         subsep = ", ";
 453                         print_joined("tag ", "tags ", &src_data->tag, out);
 454                 }
 455                 if (src_data->generic.nr) {
 456                         strbuf_addstr(out, subsep);
 457                         print_joined("commit ", "commits ", &src_data->generic,
 458                                         out);
 459                 }
 460                 if (strcmp(".", srcs.items[i].string))
 461                         strbuf_addf(out, " of %s", srcs.items[i].string);
 462         }
 463
 464         if (!strcmp("master", current_branch))
 465                 strbuf_addch(out, '\n');
 466         else
 467                 strbuf_addf(out, " into %s\n", current_branch);
 468 }
 469
 470 static void fmt_tag_signature(struct strbuf *tagbuf,
 471                               struct strbuf *sig,
 472                               const char *buf,
 473                               unsigned long len)
 474 {
 475         const char *tag_body = strstr(buf, "\n\n");
 476         if (tag_body) {
 477                 tag_body += 2;
 478                 strbuf_add(tagbuf, tag_body, buf + len - tag_body);
 479         }
 480         strbuf_complete_line(tagbuf);
 481         if (sig->len) {
 482                 strbuf_addch(tagbuf, '\n');
 483                 strbuf_add_commented_lines(tagbuf, sig->buf, sig->len);
 484         }
 485 }
 486
 487 static void fmt_merge_msg_sigs(struct strbuf *out)
 488 {
 489         int i, tag_number = 0, first_tag = 0;
 490         struct strbuf tagbuf = STRBUF_INIT;
 491
 492         for (i = 0; i < origins.nr; i++) {
 493                 struct object_id *oid = origins.items[i].util;
 494                 enum object_type type;
 495                 unsigned long size, len;
 496                 char *buf = read_object_file(oid, &type, &size);
 497                 struct strbuf sig = STRBUF_INIT;
 498
 499                 if (!buf || type != OBJ_TAG)
 500                         goto next;
 501                 len = parse_signature(buf, size);
 502
 503                 if (size == len)
 504                         ; /* merely annotated */
 505                 else if (verify_signed_buffer(buf, len, buf + len, size - len, &sig, NULL)) {
 506                         if (!sig.len)
 507                                 strbuf_addstr(&sig, "gpg verification failed.\n");
 508                 }
 509
 510                 if (!tag_number++) {
 511                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 512                         first_tag = i;
 513                 } else {
 514                         if (tag_number == 2) {
 515                                 struct strbuf tagline = STRBUF_INIT;
 516                                 strbuf_addch(&tagline, '\n');
 517                                 strbuf_add_commented_lines(&tagline,
 518                                                 origins.items[first_tag].string,
 519                                                 strlen(origins.items[first_tag].string));
 520                                 strbuf_insert(&tagbuf, 0, tagline.buf,
 521                                               tagline.len);
 522                                 strbuf_release(&tagline);
 523                         }
 524                         strbuf_addch(&tagbuf, '\n');
 525                         strbuf_add_commented_lines(&tagbuf,
 526                                         origins.items[i].string,
 527                                         strlen(origins.items[i].string));
 528                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 529                 }
 530                 strbuf_release(&sig);
 531         next:
 532                 free(buf);
 533         }
 534         if (tagbuf.len) {
 535                 strbuf_addch(out, '\n');
 536                 strbuf_addbuf(out, &tagbuf);
 537         }
 538         strbuf_release(&tagbuf);
 539 }
 540
 541 static void find_merge_parents(struct merge_parents *result,
 542                                struct strbuf *in, struct object_id *head)
 543 {
 544         struct commit_list *parents;
 545         struct commit *head_commit;
 546         int pos = 0, i, j;
 547
 548         parents = NULL;
 549         while (pos < in->len) {
 550                 int len;
 551                 char *p = in->buf + pos;
 552                 char *newline = strchr(p, '\n');
 553                 const char *q;
 554                 struct object_id oid;
 555                 struct commit *parent;
 556                 struct object *obj;
 557
 558                 len = newline ? newline - p : strlen(p);
 559                 pos += len + !!newline;
 560
 561                 if (parse_oid_hex(p, &oid, &q) ||
 562                     q[0] != '\t' ||
 563                     q[1] != '\t')
 564                         continue; /* skip not-for-merge */
 565                 /*
 566                  * Do not use get_merge_parent() here; we do not have
 567                  * "name" here and we do not want to contaminate its
 568                  * util field yet.
 569                  */
 570                 obj = parse_object(the_repository, &oid);
 571                 parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
 572                 if (!parent)
 573                         continue;
 574                 commit_list_insert(parent, &parents);
 575                 add_merge_parent(result, &obj->oid, &parent->object.oid);
 576         }
 577         head_commit = lookup_commit(the_repository, head);
 578         if (head_commit)
 579                 commit_list_insert(head_commit, &parents);
 580         reduce_heads_replace(&parents);
 581
 582         while (parents) {
 583                 struct commit *cmit = pop_commit(&parents);
 584                 for (i = 0; i < result->nr; i++)
 585                         if (oideq(&result->item[i].commit, &cmit->object.oid))
 586                                 result->item[i].used = 1;
 587         }
 588
 589         for (i = j = 0; i < result->nr; i++) {
 590                 if (result->item[i].used) {
 591                         if (i != j)
 592                                 result->item[j] = result->item[i];
 593                         j++;
 594                 }
 595         }
 596         result->nr = j;
 597 }
 598
 599 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 600                   struct fmt_merge_msg_opts *opts)
 601 {
 602         int i = 0, pos = 0;
 603         struct object_id head_oid;
 604         const char *current_branch;
 605         void *current_branch_to_free;
 606         struct merge_parents merge_parents;
 607
 608         memset(&merge_parents, 0, sizeof(merge_parents));
 609
 610         /* get current branch */
 611         current_branch = current_branch_to_free =
 612                 resolve_refdup("HEAD", RESOLVE_REF_READING, &head_oid, NULL);
 613         if (!current_branch)
 614                 die("No current branch");
 615         if (starts_with(current_branch, "refs/heads/"))
 616                 current_branch += 11;
 617
 618         find_merge_parents(&merge_parents, in, &head_oid);
 619
 620         /* get a line */
 621         while (pos < in->len) {
 622                 int len;
 623                 char *newline, *p = in->buf + pos;
 624
 625                 newline = strchr(p, '\n');
 626                 len = newline ? newline - p : strlen(p);
 627                 pos += len + !!newline;
 628                 i++;
 629                 p[len] = 0;
 630                 if (handle_line(p, &merge_parents))
 631                         die("error in line %d: %.*s", i, len, p);
 632         }
 633
 634         if (opts->add_title && srcs.nr)
 635                 fmt_merge_msg_title(out, current_branch);
 636
 637         if (origins.nr)
 638                 fmt_merge_msg_sigs(out);
 639
 640         if (opts->shortlog_len) {
 641                 struct commit *head;
 642                 struct rev_info rev;
 643
 644                 head = lookup_commit_or_die(&head_oid, "HEAD");
 645                 repo_init_revisions(the_repository, &rev, NULL);
 646                 rev.commit_format = CMIT_FMT_ONELINE;
 647                 rev.ignore_merges = 1;
 648                 rev.limited = 1;
 649
 650                 strbuf_complete_line(out);
 651
 652                 for (i = 0; i < origins.nr; i++)
 653                         shortlog(origins.items[i].string,
 654                                  origins.items[i].util,
 655                                  head, &rev, opts, out);
 656         }
 657
 658         strbuf_complete_line(out);
 659         free(current_branch_to_free);
 660         free(merge_parents.item);
 661         return 0;
 662 }
 663
 664 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 665 {
 666         const char *inpath = NULL;
 667         const char *message = NULL;
 668         int shortlog_len = -1;
 669         struct option options[] = {
 670                 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
 671                   N_("populate log with at most <n> entries from shortlog"),
 672                   PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
 673                 { OPTION_INTEGER, 0, "summary", &shortlog_len, N_("n"),
 674                   N_("alias for --log (deprecated)"),
 675                   PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
 676                   DEFAULT_MERGE_LOG_LEN },
 677                 OPT_STRING('m', "message", &message, N_("text"),
 678                         N_("use <text> as start of message")),
 679                 OPT_FILENAME('F', "file", &inpath, N_("file to read from")),
 680                 OPT_END()
 681         };
 682
 683         FILE *in = stdin;
 684         struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
 685         int ret;
 686         struct fmt_merge_msg_opts opts;
 687
 688         git_config(fmt_merge_msg_config, NULL);
 689         argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
 690                              0);
 691         if (argc > 0)
 692                 usage_with_options(fmt_merge_msg_usage, options);
 693         if (shortlog_len < 0)
 694                 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
 695
 696         if (inpath && strcmp(inpath, "-")) {
 697                 in = fopen(inpath, "r");
 698                 if (!in)
 699                         die_errno("cannot open '%s'", inpath);
 700         }
 701
 702         if (strbuf_read(&input, fileno(in), 0) < 0)
 703                 die_errno("could not read input file");
 704
 705         if (message)
 706                 strbuf_addstr(&output, message);
 707
 708         memset(&opts, 0, sizeof(opts));
 709         opts.add_title = !message;
 710         opts.credit_people = 1;
 711         opts.shortlog_len = shortlog_len;
 712
 713         ret = fmt_merge_msg(&input, &output, &opts);
 714         if (ret)
 715                 return ret;
 716         write_in_full(STDOUT_FILENO, output.buf, output.len);
 717         return 0;
 718 }