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