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

   1 #include "builtin.h"
   2 #include "cache.h"
   3 #include "commit.h"
   4 #include "diff.h"
   5 #include "revision.h"
   6 #include "tag.h"
   7 #include "string-list.h"
   8 #include "branch.h"
   9 #include "fmt-merge-msg.h"
  10 #include "gpg-interface.h"
  11
  12 static const char * const fmt_merge_msg_usage[] = {
  13         N_("git fmt-merge-msg [-m <message>] [--log[=<n>]|--no-log] [--file <file>]"),
  14         NULL
  15 };
  16
  17 static int use_branch_desc;
  18
  19 int fmt_merge_msg_config(const char *key, const char *value, void *cb)
  20 {
  21         if (!strcmp(key, "merge.log") || !strcmp(key, "merge.summary")) {
  22                 int is_bool;
  23                 merge_log_config = git_config_bool_or_int(key, value, &is_bool);
  24                 if (!is_bool && merge_log_config < 0)
  25                         return error("%s: negative length %s", key, value);
  26                 if (is_bool && merge_log_config)
  27                         merge_log_config = DEFAULT_MERGE_LOG_LEN;
  28         } else if (!strcmp(key, "merge.branchdesc")) {
  29                 use_branch_desc = git_config_bool(key, value);
  30         } else {
  31                 return git_default_config(key, value, cb);
  32         }
  33         return 0;
  34 }
  35
  36 /* merge data per repository where the merged tips came from */
  37 struct src_data {
  38         struct string_list branch, tag, r_branch, generic;
  39         int head_status;
  40 };
  41
  42 struct origin_data {
  43         unsigned char sha1[20];
  44         unsigned is_local_branch:1;
  45 };
  46
  47 static void init_src_data(struct src_data *data)
  48 {
  49         data->branch.strdup_strings = 1;
  50         data->tag.strdup_strings = 1;
  51         data->r_branch.strdup_strings = 1;
  52         data->generic.strdup_strings = 1;
  53 }
  54
  55 static struct string_list srcs = STRING_LIST_INIT_DUP;
  56 static struct string_list origins = STRING_LIST_INIT_DUP;
  57
  58 struct merge_parents {
  59         int alloc, nr;
  60         struct merge_parent {
  61                 unsigned char given[20];
  62                 unsigned char commit[20];
  63                 unsigned char used;
  64         } *item;
  65 };
  66
  67 /*
  68  * I know, I know, this is inefficient, but you won't be pulling and merging
  69  * hundreds of heads at a time anyway.
  70  */
  71 static struct merge_parent *find_merge_parent(struct merge_parents *table,
  72                                               unsigned char *given,
  73                                               unsigned char *commit)
  74 {
  75         int i;
  76         for (i = 0; i < table->nr; i++) {
  77                 if (given && hashcmp(table->item[i].given, given))
  78                         continue;
  79                 if (commit && hashcmp(table->item[i].commit, commit))
  80                         continue;
  81                 return &table->item[i];
  82         }
  83         return NULL;
  84 }
  85
  86 static void add_merge_parent(struct merge_parents *table,
  87                              unsigned char *given,
  88                              unsigned char *commit)
  89 {
  90         if (table->nr && find_merge_parent(table, given, commit))
  91                 return;
  92         ALLOC_GROW(table->item, table->nr + 1, table->alloc);
  93         hashcpy(table->item[table->nr].given, given);
  94         hashcpy(table->item[table->nr].commit, commit);
  95         table->item[table->nr].used = 0;
  96         table->nr++;
  97 }
  98
  99 static int handle_line(char *line, struct merge_parents *merge_parents)
 100 {
 101         int i, len = strlen(line);
 102         struct origin_data *origin_data;
 103         char *src, *origin;
 104         struct src_data *src_data;
 105         struct string_list_item *item;
 106         int pulling_head = 0;
 107         unsigned char sha1[20];
 108
 109         if (len < 43 || line[40] != '\t')
 110                 return 1;
 111
 112         if (!prefixcmp(line + 41, "not-for-merge"))
 113                 return 0;
 114
 115         if (line[41] != '\t')
 116                 return 2;
 117
 118         i = get_sha1_hex(line, sha1);
 119         if (i)
 120                 return 3;
 121
 122         if (!find_merge_parent(merge_parents, sha1, NULL))
 123                 return 0; /* subsumed by other parents */
 124
 125         origin_data = xcalloc(1, sizeof(struct origin_data));
 126         hashcpy(origin_data->sha1, sha1);
 127
 128         if (line[len - 1] == '\n')
 129                 line[len - 1] = 0;
 130         line += 42;
 131
 132         /*
 133          * At this point, line points at the beginning of comment e.g.
 134          * "branch 'frotz' of git://that/repository.git".
 135          * Find the repository name and point it with src.
 136          */
 137         src = strstr(line, " of ");
 138         if (src) {
 139                 *src = 0;
 140                 src += 4;
 141                 pulling_head = 0;
 142         } else {
 143                 src = line;
 144                 pulling_head = 1;
 145         }
 146
 147         item = unsorted_string_list_lookup(&srcs, src);
 148         if (!item) {
 149                 item = string_list_append(&srcs, src);
 150                 item->util = xcalloc(1, sizeof(struct src_data));
 151                 init_src_data(item->util);
 152         }
 153         src_data = item->util;
 154
 155         if (pulling_head) {
 156                 origin = src;
 157                 src_data->head_status |= 1;
 158         } else if (!prefixcmp(line, "branch ")) {
 159                 origin_data->is_local_branch = 1;
 160                 origin = line + 7;
 161                 string_list_append(&src_data->branch, origin);
 162                 src_data->head_status |= 2;
 163         } else if (!prefixcmp(line, "tag ")) {
 164                 origin = line;
 165                 string_list_append(&src_data->tag, origin + 4);
 166                 src_data->head_status |= 2;
 167         } else if (!prefixcmp(line, "remote-tracking branch ")) {
 168                 origin = line + strlen("remote-tracking branch ");
 169                 string_list_append(&src_data->r_branch, origin);
 170                 src_data->head_status |= 2;
 171         } else {
 172                 origin = src;
 173                 string_list_append(&src_data->generic, line);
 174                 src_data->head_status |= 2;
 175         }
 176
 177         if (!strcmp(".", src) || !strcmp(src, origin)) {
 178                 int len = strlen(origin);
 179                 if (origin[0] == '\'' && origin[len - 1] == '\'')
 180                         origin = xmemdupz(origin + 1, len - 2);
 181         } else {
 182                 char *new_origin = xmalloc(strlen(origin) + strlen(src) + 5);
 183                 sprintf(new_origin, "%s of %s", origin, src);
 184                 origin = new_origin;
 185         }
 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                 if (out->buf[out->len - 1] != '\n')
 223                         strbuf_addch(out, '\n');
 224         }
 225         strbuf_release(&desc);
 226 }
 227
 228 #define util_as_integral(elem) ((intptr_t)((elem)->util))
 229
 230 static void record_person(int which, struct string_list *people,
 231                           struct commit *commit)
 232 {
 233         char *name_buf, *name, *name_end;
 234         struct string_list_item *elem;
 235         const char *field = (which == 'a') ? "\nauthor " : "\ncommitter ";
 236
 237         name = strstr(commit->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 static int cmp_string_list_util_as_integral(const void *a_, const void *b_)
 260 {
 261         const struct string_list_item *a = a_, *b = b_;
 262         return util_as_integral(b) - util_as_integral(a);
 263 }
 264
 265 static void add_people_count(struct strbuf *out, struct string_list *people)
 266 {
 267         if (people->nr == 1)
 268                 strbuf_addf(out, "%s", people->items[0].string);
 269         else if (people->nr == 2)
 270                 strbuf_addf(out, "%s (%d) and %s (%d)",
 271                             people->items[0].string,
 272                             (int)util_as_integral(&people->items[0]),
 273                             people->items[1].string,
 274                             (int)util_as_integral(&people->items[1]));
 275         else if (people->nr)
 276                 strbuf_addf(out, "%s (%d) and others",
 277                             people->items[0].string,
 278                             (int)util_as_integral(&people->items[0]));
 279 }
 280
 281 static void credit_people(struct strbuf *out,
 282                           struct string_list *them,
 283                           int kind)
 284 {
 285         const char *label;
 286         const char *me;
 287
 288         if (kind == 'a') {
 289                 label = "\n# By ";
 290                 me = git_author_info(IDENT_NO_DATE);
 291         } else {
 292                 label = "\n# Via ";
 293                 me = git_committer_info(IDENT_NO_DATE);
 294         }
 295
 296         if (!them->nr ||
 297             (them->nr == 1 &&
 298              me &&
 299              (me = skip_prefix(me, them->items->string)) != NULL &&
 300              skip_prefix(me, " <")))
 301                 return;
 302         strbuf_addstr(out, label);
 303         add_people_count(out, them);
 304 }
 305
 306 static void add_people_info(struct strbuf *out,
 307                             struct string_list *authors,
 308                             struct string_list *committers)
 309 {
 310         if (authors->nr)
 311                 qsort(authors->items,
 312                       authors->nr, sizeof(authors->items[0]),
 313                       cmp_string_list_util_as_integral);
 314         if (committers->nr)
 315                 qsort(committers->items,
 316                       committers->nr, sizeof(committers->items[0]),
 317                       cmp_string_list_util_as_integral);
 318
 319         credit_people(out, authors, 'a');
 320         credit_people(out, committers, 'c');
 321 }
 322
 323 static void shortlog(const char *name,
 324                      struct origin_data *origin_data,
 325                      struct commit *head,
 326                      struct rev_info *rev, int limit,
 327                      struct strbuf *out)
 328 {
 329         int i, count = 0;
 330         struct commit *commit;
 331         struct object *branch;
 332         struct string_list subjects = STRING_LIST_INIT_DUP;
 333         struct string_list authors = STRING_LIST_INIT_DUP;
 334         struct string_list committers = STRING_LIST_INIT_DUP;
 335         int flags = UNINTERESTING | TREESAME | SEEN | SHOWN | ADDED;
 336         struct strbuf sb = STRBUF_INIT;
 337         const unsigned char *sha1 = origin_data->sha1;
 338
 339         branch = deref_tag(parse_object(sha1), sha1_to_hex(sha1), 40);
 340         if (!branch || branch->type != OBJ_COMMIT)
 341                 return;
 342
 343         setup_revisions(0, NULL, rev, NULL);
 344         add_pending_object(rev, branch, name);
 345         add_pending_object(rev, &head->object, "^HEAD");
 346         head->object.flags |= UNINTERESTING;
 347         if (prepare_revision_walk(rev))
 348                 die("revision walk setup failed");
 349         while ((commit = get_revision(rev)) != NULL) {
 350                 struct pretty_print_context ctx = {0};
 351
 352                 if (commit->parents && commit->parents->next) {
 353                         /* do not list a merge but count committer */
 354                         record_person('c', &committers, commit);
 355                         continue;
 356                 }
 357                 if (!count)
 358                         /* the 'tip' committer */
 359                         record_person('c', &committers, commit);
 360                 record_person('a', &authors, commit);
 361                 count++;
 362                 if (subjects.nr > limit)
 363                         continue;
 364
 365                 format_commit_message(commit, "%s", &sb, &ctx);
 366                 strbuf_ltrim(&sb);
 367
 368                 if (!sb.len)
 369                         string_list_append(&subjects,
 370                                            sha1_to_hex(commit->object.sha1));
 371                 else
 372                         string_list_append(&subjects, strbuf_detach(&sb, NULL));
 373         }
 374
 375         add_people_info(out, &authors, &committers);
 376         if (count > limit)
 377                 strbuf_addf(out, "\n* %s: (%d commits)\n", name, count);
 378         else
 379                 strbuf_addf(out, "\n* %s:\n", name);
 380
 381         if (origin_data->is_local_branch && use_branch_desc)
 382                 add_branch_desc(out, name);
 383
 384         for (i = 0; i < subjects.nr; i++)
 385                 if (i >= limit)
 386                         strbuf_addf(out, "  ...\n");
 387                 else
 388                         strbuf_addf(out, "  %s\n", subjects.items[i].string);
 389
 390         clear_commit_marks((struct commit *)branch, flags);
 391         clear_commit_marks(head, flags);
 392         free_commit_list(rev->commits);
 393         rev->commits = NULL;
 394         rev->pending.nr = 0;
 395
 396         string_list_clear(&authors, 0);
 397         string_list_clear(&committers, 0);
 398         string_list_clear(&subjects, 0);
 399 }
 400
 401 static void fmt_merge_msg_title(struct strbuf *out,
 402         const char *current_branch) {
 403         int i = 0;
 404         char *sep = "";
 405
 406         strbuf_addstr(out, "Merge ");
 407         for (i = 0; i < srcs.nr; i++) {
 408                 struct src_data *src_data = srcs.items[i].util;
 409                 const char *subsep = "";
 410
 411                 strbuf_addstr(out, sep);
 412                 sep = "; ";
 413
 414                 if (src_data->head_status == 1) {
 415                         strbuf_addstr(out, srcs.items[i].string);
 416                         continue;
 417                 }
 418                 if (src_data->head_status == 3) {
 419                         subsep = ", ";
 420                         strbuf_addstr(out, "HEAD");
 421                 }
 422                 if (src_data->branch.nr) {
 423                         strbuf_addstr(out, subsep);
 424                         subsep = ", ";
 425                         print_joined("branch ", "branches ", &src_data->branch,
 426                                         out);
 427                 }
 428                 if (src_data->r_branch.nr) {
 429                         strbuf_addstr(out, subsep);
 430                         subsep = ", ";
 431                         print_joined("remote-tracking branch ", "remote-tracking branches ",
 432                                         &src_data->r_branch, out);
 433                 }
 434                 if (src_data->tag.nr) {
 435                         strbuf_addstr(out, subsep);
 436                         subsep = ", ";
 437                         print_joined("tag ", "tags ", &src_data->tag, out);
 438                 }
 439                 if (src_data->generic.nr) {
 440                         strbuf_addstr(out, subsep);
 441                         print_joined("commit ", "commits ", &src_data->generic,
 442                                         out);
 443                 }
 444                 if (strcmp(".", srcs.items[i].string))
 445                         strbuf_addf(out, " of %s", srcs.items[i].string);
 446         }
 447
 448         if (!strcmp("master", current_branch))
 449                 strbuf_addch(out, '\n');
 450         else
 451                 strbuf_addf(out, " into %s\n", current_branch);
 452 }
 453
 454 static void fmt_tag_signature(struct strbuf *tagbuf,
 455                               struct strbuf *sig,
 456                               const char *buf,
 457                               unsigned long len)
 458 {
 459         const char *tag_body = strstr(buf, "\n\n");
 460         if (tag_body) {
 461                 tag_body += 2;
 462                 strbuf_add(tagbuf, tag_body, buf + len - tag_body);
 463         }
 464         strbuf_complete_line(tagbuf);
 465         if (sig->len) {
 466                 strbuf_addch(tagbuf, '\n');
 467                 strbuf_add_lines(tagbuf, "# ", sig->buf, sig->len);
 468         }
 469 }
 470
 471 static void fmt_merge_msg_sigs(struct strbuf *out)
 472 {
 473         int i, tag_number = 0, first_tag = 0;
 474         struct strbuf tagbuf = STRBUF_INIT;
 475
 476         for (i = 0; i < origins.nr; i++) {
 477                 unsigned char *sha1 = origins.items[i].util;
 478                 enum object_type type;
 479                 unsigned long size, len;
 480                 char *buf = read_sha1_file(sha1, &type, &size);
 481                 struct strbuf sig = STRBUF_INIT;
 482
 483                 if (!buf || type != OBJ_TAG)
 484                         goto next;
 485                 len = parse_signature(buf, size);
 486
 487                 if (size == len)
 488                         ; /* merely annotated */
 489                 else if (verify_signed_buffer(buf, len, buf + len, size - len, &sig)) {
 490                         if (!sig.len)
 491                                 strbuf_addstr(&sig, "gpg verification failed.\n");
 492                 }
 493
 494                 if (!tag_number++) {
 495                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 496                         first_tag = i;
 497                 } else {
 498                         if (tag_number == 2) {
 499                                 struct strbuf tagline = STRBUF_INIT;
 500                                 strbuf_addf(&tagline, "\n# %s\n",
 501                                             origins.items[first_tag].string);
 502                                 strbuf_insert(&tagbuf, 0, tagline.buf,
 503                                               tagline.len);
 504                                 strbuf_release(&tagline);
 505                         }
 506                         strbuf_addf(&tagbuf, "\n# %s\n",
 507                                     origins.items[i].string);
 508                         fmt_tag_signature(&tagbuf, &sig, buf, len);
 509                 }
 510                 strbuf_release(&sig);
 511         next:
 512                 free(buf);
 513         }
 514         if (tagbuf.len) {
 515                 strbuf_addch(out, '\n');
 516                 strbuf_addbuf(out, &tagbuf);
 517         }
 518         strbuf_release(&tagbuf);
 519 }
 520
 521 static void find_merge_parents(struct merge_parents *result,
 522                                struct strbuf *in, unsigned char *head)
 523 {
 524         struct commit_list *parents, *next;
 525         struct commit *head_commit;
 526         int pos = 0, i, j;
 527
 528         parents = NULL;
 529         while (pos < in->len) {
 530                 int len;
 531                 char *p = in->buf + pos;
 532                 char *newline = strchr(p, '\n');
 533                 unsigned char sha1[20];
 534                 struct commit *parent;
 535                 struct object *obj;
 536
 537                 len = newline ? newline - p : strlen(p);
 538                 pos += len + !!newline;
 539
 540                 if (len < 43 ||
 541                     get_sha1_hex(p, sha1) ||
 542                     p[40] != '\t' ||
 543                     p[41] != '\t')
 544                         continue; /* skip not-for-merge */
 545                 /*
 546                  * Do not use get_merge_parent() here; we do not have
 547                  * "name" here and we do not want to contaminate its
 548                  * util field yet.
 549                  */
 550                 obj = parse_object(sha1);
 551                 parent = (struct commit *)peel_to_type(NULL, 0, obj, OBJ_COMMIT);
 552                 if (!parent)
 553                         continue;
 554                 commit_list_insert(parent, &parents);
 555                 add_merge_parent(result, obj->sha1, parent->object.sha1);
 556         }
 557         head_commit = lookup_commit(head);
 558         if (head_commit)
 559                 commit_list_insert(head_commit, &parents);
 560         parents = reduce_heads(parents);
 561
 562         while (parents) {
 563                 for (i = 0; i < result->nr; i++)
 564                         if (!hashcmp(result->item[i].commit,
 565                                      parents->item->object.sha1))
 566                                 result->item[i].used = 1;
 567                 next = parents->next;
 568                 free(parents);
 569                 parents = next;
 570         }
 571
 572         for (i = j = 0; i < result->nr; i++) {
 573                 if (result->item[i].used) {
 574                         if (i != j)
 575                                 result->item[j] = result->item[i];
 576                         j++;
 577                 }
 578         }
 579         result->nr = j;
 580 }
 581
 582 int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 583                   struct fmt_merge_msg_opts *opts)
 584 {
 585         int i = 0, pos = 0;
 586         unsigned char head_sha1[20];
 587         const char *current_branch;
 588         void *current_branch_to_free;
 589         struct merge_parents merge_parents;
 590
 591         memset(&merge_parents, 0, sizeof(merge_parents));
 592
 593         /* get current branch */
 594         current_branch = current_branch_to_free =
 595                 resolve_refdup("HEAD", head_sha1, 1, NULL);
 596         if (!current_branch)
 597                 die("No current branch");
 598         if (!prefixcmp(current_branch, "refs/heads/"))
 599                 current_branch += 11;
 600
 601         find_merge_parents(&merge_parents, in, head_sha1);
 602
 603         /* get a line */
 604         while (pos < in->len) {
 605                 int len;
 606                 char *newline, *p = in->buf + pos;
 607
 608                 newline = strchr(p, '\n');
 609                 len = newline ? newline - p : strlen(p);
 610                 pos += len + !!newline;
 611                 i++;
 612                 p[len] = 0;
 613                 if (handle_line(p, &merge_parents))
 614                         die ("Error in line %d: %.*s", i, len, p);
 615         }
 616
 617         if (opts->add_title && srcs.nr)
 618                 fmt_merge_msg_title(out, current_branch);
 619
 620         if (origins.nr)
 621                 fmt_merge_msg_sigs(out);
 622
 623         if (opts->shortlog_len) {
 624                 struct commit *head;
 625                 struct rev_info rev;
 626
 627                 head = lookup_commit_or_die(head_sha1, "HEAD");
 628                 init_revisions(&rev, NULL);
 629                 rev.commit_format = CMIT_FMT_ONELINE;
 630                 rev.ignore_merges = 1;
 631                 rev.limited = 1;
 632
 633                 strbuf_complete_line(out);
 634
 635                 for (i = 0; i < origins.nr; i++)
 636                         shortlog(origins.items[i].string,
 637                                  origins.items[i].util,
 638                                  head, &rev, opts->shortlog_len, out);
 639         }
 640
 641         strbuf_complete_line(out);
 642         free(current_branch_to_free);
 643         free(merge_parents.item);
 644         return 0;
 645 }
 646
 647 int cmd_fmt_merge_msg(int argc, const char **argv, const char *prefix)
 648 {
 649         const char *inpath = NULL;
 650         const char *message = NULL;
 651         int shortlog_len = -1;
 652         struct option options[] = {
 653                 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
 654                   N_("populate log with at most <n> entries from shortlog"),
 655                   PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
 656                 { OPTION_INTEGER, 0, "summary", &shortlog_len, N_("n"),
 657                   N_("alias for --log (deprecated)"),
 658                   PARSE_OPT_OPTARG | PARSE_OPT_HIDDEN, NULL,
 659                   DEFAULT_MERGE_LOG_LEN },
 660                 OPT_STRING('m', "message", &message, N_("text"),
 661                         N_("use <text> as start of message")),
 662                 OPT_FILENAME('F', "file", &inpath, N_("file to read from")),
 663                 OPT_END()
 664         };
 665
 666         FILE *in = stdin;
 667         struct strbuf input = STRBUF_INIT, output = STRBUF_INIT;
 668         int ret;
 669         struct fmt_merge_msg_opts opts;
 670
 671         git_config(fmt_merge_msg_config, NULL);
 672         argc = parse_options(argc, argv, prefix, options, fmt_merge_msg_usage,
 673                              0);
 674         if (argc > 0)
 675                 usage_with_options(fmt_merge_msg_usage, options);
 676         if (shortlog_len < 0)
 677                 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
 678
 679         if (inpath && strcmp(inpath, "-")) {
 680                 in = fopen(inpath, "r");
 681                 if (!in)
 682                         die_errno("cannot open '%s'", inpath);
 683         }
 684
 685         if (strbuf_read(&input, fileno(in), 0) < 0)
 686                 die_errno("could not read input file");
 687
 688         if (message)
 689                 strbuf_addstr(&output, message);
 690
 691         memset(&opts, 0, sizeof(opts));
 692         opts.add_title = !message;
 693         opts.shortlog_len = shortlog_len;
 694
 695         ret = fmt_merge_msg(&input, &output, &opts);
 696         if (ret)
 697                 return ret;
 698         write_in_full(STDOUT_FILENO, output.buf, output.len);
 699         return 0;
 700 }