builtin/merge.c

   1 /*
   2  * Builtin "git merge"
   3  *
   4  * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
   5  *
   6  * Based on git-merge.sh by Junio C Hamano.
   7  */
   8
   9 #include "cache.h"
  10 #include "parse-options.h"
  11 #include "builtin.h"
  12 #include "run-command.h"
  13 #include "diff.h"
  14 #include "refs.h"
  15 #include "commit.h"
  16 #include "diffcore.h"
  17 #include "revision.h"
  18 #include "unpack-trees.h"
  19 #include "cache-tree.h"
  20 #include "dir.h"
  21 #include "utf8.h"
  22 #include "log-tree.h"
  23 #include "color.h"
  24 #include "rerere.h"
  25 #include "help.h"
  26 #include "merge-recursive.h"
  27 #include "resolve-undo.h"
  28
  29 #define DEFAULT_TWOHEAD (1<<0)
  30 #define DEFAULT_OCTOPUS (1<<1)
  31 #define NO_FAST_FORWARD (1<<2)
  32 #define NO_TRIVIAL      (1<<3)
  33
  34 struct strategy {
  35         const char *name;
  36         unsigned attr;
  37 };
  38
  39 static const char * const builtin_merge_usage[] = {
  40         "git merge [options] <remote>...",
  41         "git merge [options] <msg> HEAD <remote>",
  42         NULL
  43 };
  44
  45 static int show_diffstat = 1, option_log, squash;
  46 static int option_commit = 1, allow_fast_forward = 1;
  47 static int fast_forward_only;
  48 static int allow_trivial = 1, have_message;
  49 static struct strbuf merge_msg;
  50 static struct commit_list *remoteheads;
  51 static unsigned char head[20], stash[20];
  52 static struct strategy **use_strategies;
  53 static size_t use_strategies_nr, use_strategies_alloc;
  54 static const char **xopts;
  55 static size_t xopts_nr, xopts_alloc;
  56 static const char *branch;
  57 static int option_renormalize;
  58 static int verbosity;
  59 static int allow_rerere_auto;
  60
  61 static struct strategy all_strategy[] = {
  62         { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
  63         { "octopus",    DEFAULT_OCTOPUS },
  64         { "resolve",    0 },
  65         { "ours",       NO_FAST_FORWARD | NO_TRIVIAL },
  66         { "subtree",    NO_FAST_FORWARD | NO_TRIVIAL },
  67 };
  68
  69 static const char *pull_twohead, *pull_octopus;
  70
  71 static int option_parse_message(const struct option *opt,
  72                                 const char *arg, int unset)
  73 {
  74         struct strbuf *buf = opt->value;
  75
  76         if (unset)
  77                 strbuf_setlen(buf, 0);
  78         else if (arg) {
  79                 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
  80                 have_message = 1;
  81         } else
  82                 return error("switch `m' requires a value");
  83         return 0;
  84 }
  85
  86 static struct strategy *get_strategy(const char *name)
  87 {
  88         int i;
  89         struct strategy *ret;
  90         static struct cmdnames main_cmds, other_cmds;
  91         static int loaded;
  92
  93         if (!name)
  94                 return NULL;
  95
  96         for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
  97                 if (!strcmp(name, all_strategy[i].name))
  98                         return &all_strategy[i];
  99
 100         if (!loaded) {
 101                 struct cmdnames not_strategies;
 102                 loaded = 1;
 103
 104                 memset(&not_strategies, 0, sizeof(struct cmdnames));
 105                 load_command_list("git-merge-", &main_cmds, &other_cmds);
 106                 for (i = 0; i < main_cmds.cnt; i++) {
 107                         int j, found = 0;
 108                         struct cmdname *ent = main_cmds.names[i];
 109                         for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
 110                                 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
 111                                                 && !all_strategy[j].name[ent->len])
 112                                         found = 1;
 113                         if (!found)
 114                                 add_cmdname(&not_strategies, ent->name, ent->len);
 115                 }
 116                 exclude_cmds(&main_cmds, &not_strategies);
 117         }
 118         if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
 119                 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
 120                 fprintf(stderr, "Available strategies are:");
 121                 for (i = 0; i < main_cmds.cnt; i++)
 122                         fprintf(stderr, " %s", main_cmds.names[i]->name);
 123                 fprintf(stderr, ".\n");
 124                 if (other_cmds.cnt) {
 125                         fprintf(stderr, "Available custom strategies are:");
 126                         for (i = 0; i < other_cmds.cnt; i++)
 127                                 fprintf(stderr, " %s", other_cmds.names[i]->name);
 128                         fprintf(stderr, ".\n");
 129                 }
 130                 exit(1);
 131         }
 132
 133         ret = xcalloc(1, sizeof(struct strategy));
 134         ret->name = xstrdup(name);
 135         ret->attr = NO_TRIVIAL;
 136         return ret;
 137 }
 138
 139 static void append_strategy(struct strategy *s)
 140 {
 141         ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
 142         use_strategies[use_strategies_nr++] = s;
 143 }
 144
 145 static int option_parse_strategy(const struct option *opt,
 146                                  const char *name, int unset)
 147 {
 148         if (unset)
 149                 return 0;
 150
 151         append_strategy(get_strategy(name));
 152         return 0;
 153 }
 154
 155 static int option_parse_x(const struct option *opt,
 156                           const char *arg, int unset)
 157 {
 158         if (unset)
 159                 return 0;
 160
 161         ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
 162         xopts[xopts_nr++] = xstrdup(arg);
 163         return 0;
 164 }
 165
 166 static int option_parse_n(const struct option *opt,
 167                           const char *arg, int unset)
 168 {
 169         show_diffstat = unset;
 170         return 0;
 171 }
 172
 173 static struct option builtin_merge_options[] = {
 174         { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
 175                 "do not show a diffstat at the end of the merge",
 176                 PARSE_OPT_NOARG, option_parse_n },
 177         OPT_BOOLEAN(0, "stat", &show_diffstat,
 178                 "show a diffstat at the end of the merge"),
 179         OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
 180         OPT_BOOLEAN(0, "log", &option_log,
 181                 "add list of one-line log to merge commit message"),
 182         OPT_BOOLEAN(0, "squash", &squash,
 183                 "create a single commit instead of doing a merge"),
 184         OPT_BOOLEAN(0, "commit", &option_commit,
 185                 "perform a commit if the merge succeeds (default)"),
 186         OPT_BOOLEAN(0, "ff", &allow_fast_forward,
 187                 "allow fast-forward (default)"),
 188         OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
 189                 "abort if fast-forward is not possible"),
 190         OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 191         OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
 192                 "merge strategy to use", option_parse_strategy),
 193         OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
 194                 "option for selected merge strategy", option_parse_x),
 195         OPT_CALLBACK('m', "message", &merge_msg, "message",
 196                 "message to be used for the merge commit (if any)",
 197                 option_parse_message),
 198         OPT__VERBOSITY(&verbosity),
 199         OPT_END()
 200 };
 201
 202 /* Cleans up metadata that is uninteresting after a succeeded merge. */
 203 static void drop_save(void)
 204 {
 205         unlink(git_path("MERGE_HEAD"));
 206         unlink(git_path("MERGE_MSG"));
 207         unlink(git_path("MERGE_MODE"));
 208 }
 209
 210 static void save_state(void)
 211 {
 212         int len;
 213         struct child_process cp;
 214         struct strbuf buffer = STRBUF_INIT;
 215         const char *argv[] = {"stash", "create", NULL};
 216
 217         memset(&cp, 0, sizeof(cp));
 218         cp.argv = argv;
 219         cp.out = -1;
 220         cp.git_cmd = 1;
 221
 222         if (start_command(&cp))
 223                 die("could not run stash.");
 224         len = strbuf_read(&buffer, cp.out, 1024);
 225         close(cp.out);
 226
 227         if (finish_command(&cp) || len < 0)
 228                 die("stash failed");
 229         else if (!len)
 230                 return;
 231         strbuf_setlen(&buffer, buffer.len-1);
 232         if (get_sha1(buffer.buf, stash))
 233                 die("not a valid object: %s", buffer.buf);
 234 }
 235
 236 static void reset_hard(unsigned const char *sha1, int verbose)
 237 {
 238         int i = 0;
 239         const char *args[6];
 240
 241         args[i++] = "read-tree";
 242         if (verbose)
 243                 args[i++] = "-v";
 244         args[i++] = "--reset";
 245         args[i++] = "-u";
 246         args[i++] = sha1_to_hex(sha1);
 247         args[i] = NULL;
 248
 249         if (run_command_v_opt(args, RUN_GIT_CMD))
 250                 die("read-tree failed");
 251 }
 252
 253 static void restore_state(void)
 254 {
 255         struct strbuf sb = STRBUF_INIT;
 256         const char *args[] = { "stash", "apply", NULL, NULL };
 257
 258         if (is_null_sha1(stash))
 259                 return;
 260
 261         reset_hard(head, 1);
 262
 263         args[2] = sha1_to_hex(stash);
 264
 265         /*
 266          * It is OK to ignore error here, for example when there was
 267          * nothing to restore.
 268          */
 269         run_command_v_opt(args, RUN_GIT_CMD);
 270
 271         strbuf_release(&sb);
 272         refresh_cache(REFRESH_QUIET);
 273 }
 274
 275 /* This is called when no merge was necessary. */
 276 static void finish_up_to_date(const char *msg)
 277 {
 278         if (verbosity >= 0)
 279                 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
 280         drop_save();
 281 }
 282
 283 static void squash_message(void)
 284 {
 285         struct rev_info rev;
 286         struct commit *commit;
 287         struct strbuf out = STRBUF_INIT;
 288         struct commit_list *j;
 289         int fd;
 290         struct pretty_print_context ctx = {0};
 291
 292         printf("Squash commit -- not updating HEAD\n");
 293         fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
 294         if (fd < 0)
 295                 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
 296
 297         init_revisions(&rev, NULL);
 298         rev.ignore_merges = 1;
 299         rev.commit_format = CMIT_FMT_MEDIUM;
 300
 301         commit = lookup_commit(head);
 302         commit->object.flags |= UNINTERESTING;
 303         add_pending_object(&rev, &commit->object, NULL);
 304
 305         for (j = remoteheads; j; j = j->next)
 306                 add_pending_object(&rev, &j->item->object, NULL);
 307
 308         setup_revisions(0, NULL, &rev, NULL);
 309         if (prepare_revision_walk(&rev))
 310                 die("revision walk setup failed");
 311
 312         ctx.abbrev = rev.abbrev;
 313         ctx.date_mode = rev.date_mode;
 314
 315         strbuf_addstr(&out, "Squashed commit of the following:\n");
 316         while ((commit = get_revision(&rev)) != NULL) {
 317                 strbuf_addch(&out, '\n');
 318                 strbuf_addf(&out, "commit %s\n",
 319                         sha1_to_hex(commit->object.sha1));
 320                 pretty_print_commit(rev.commit_format, commit, &out, &ctx);
 321         }
 322         if (write(fd, out.buf, out.len) < 0)
 323                 die_errno("Writing SQUASH_MSG");
 324         if (close(fd))
 325                 die_errno("Finishing SQUASH_MSG");
 326         strbuf_release(&out);
 327 }
 328
 329 static void finish(const unsigned char *new_head, const char *msg)
 330 {
 331         struct strbuf reflog_message = STRBUF_INIT;
 332
 333         if (!msg)
 334                 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
 335         else {
 336                 if (verbosity >= 0)
 337                         printf("%s\n", msg);
 338                 strbuf_addf(&reflog_message, "%s: %s",
 339                         getenv("GIT_REFLOG_ACTION"), msg);
 340         }
 341         if (squash) {
 342                 squash_message();
 343         } else {
 344                 if (verbosity >= 0 && !merge_msg.len)
 345                         printf("No merge message -- not updating HEAD\n");
 346                 else {
 347                         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 348                         update_ref(reflog_message.buf, "HEAD",
 349                                 new_head, head, 0,
 350                                 DIE_ON_ERR);
 351                         /*
 352                          * We ignore errors in 'gc --auto', since the
 353                          * user should see them.
 354                          */
 355                         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 356                 }
 357         }
 358         if (new_head && show_diffstat) {
 359                 struct diff_options opts;
 360                 diff_setup(&opts);
 361                 opts.output_format |=
 362                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 363                 opts.detect_rename = DIFF_DETECT_RENAME;
 364                 if (diff_use_color_default > 0)
 365                         DIFF_OPT_SET(&opts, COLOR_DIFF);
 366                 if (diff_setup_done(&opts) < 0)
 367                         die("diff_setup_done failed");
 368                 diff_tree_sha1(head, new_head, "", &opts);
 369                 diffcore_std(&opts);
 370                 diff_flush(&opts);
 371         }
 372
 373         /* Run a post-merge hook */
 374         run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
 375
 376         strbuf_release(&reflog_message);
 377 }
 378
 379 /* Get the name for the merge commit's message. */
 380 static void merge_name(const char *remote, struct strbuf *msg)
 381 {
 382         struct object *remote_head;
 383         unsigned char branch_head[20], buf_sha[20];
 384         struct strbuf buf = STRBUF_INIT;
 385         struct strbuf bname = STRBUF_INIT;
 386         const char *ptr;
 387         char *found_ref;
 388         int len, early;
 389
 390         strbuf_branchname(&bname, remote);
 391         remote = bname.buf;
 392
 393         memset(branch_head, 0, sizeof(branch_head));
 394         remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
 395         if (!remote_head)
 396                 die("'%s' does not point to a commit", remote);
 397
 398         if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
 399                 if (!prefixcmp(found_ref, "refs/heads/")) {
 400                         strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
 401                                     sha1_to_hex(branch_head), remote);
 402                         goto cleanup;
 403                 }
 404                 if (!prefixcmp(found_ref, "refs/remotes/")) {
 405                         strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
 406                                     sha1_to_hex(branch_head), remote);
 407                         goto cleanup;
 408                 }
 409         }
 410
 411         /* See if remote matches <name>^^^.. or <name>~<number> */
 412         for (len = 0, ptr = remote + strlen(remote);
 413              remote < ptr && ptr[-1] == '^';
 414              ptr--)
 415                 len++;
 416         if (len)
 417                 early = 1;
 418         else {
 419                 early = 0;
 420                 ptr = strrchr(remote, '~');
 421                 if (ptr) {
 422                         int seen_nonzero = 0;
 423
 424                         len++; /* count ~ */
 425                         while (*++ptr && isdigit(*ptr)) {
 426                                 seen_nonzero |= (*ptr != '0');
 427                                 len++;
 428                         }
 429                         if (*ptr)
 430                                 len = 0; /* not ...~<number> */
 431                         else if (seen_nonzero)
 432                                 early = 1;
 433                         else if (len == 1)
 434                                 early = 1; /* "name~" is "name~1"! */
 435                 }
 436         }
 437         if (len) {
 438                 struct strbuf truname = STRBUF_INIT;
 439                 strbuf_addstr(&truname, "refs/heads/");
 440                 strbuf_addstr(&truname, remote);
 441                 strbuf_setlen(&truname, truname.len - len);
 442                 if (resolve_ref(truname.buf, buf_sha, 1, NULL)) {
 443                         strbuf_addf(msg,
 444                                     "%s\t\tbranch '%s'%s of .\n",
 445                                     sha1_to_hex(remote_head->sha1),
 446                                     truname.buf + 11,
 447                                     (early ? " (early part)" : ""));
 448                         strbuf_release(&truname);
 449                         goto cleanup;
 450                 }
 451         }
 452
 453         if (!strcmp(remote, "FETCH_HEAD") &&
 454                         !access(git_path("FETCH_HEAD"), R_OK)) {
 455                 FILE *fp;
 456                 struct strbuf line = STRBUF_INIT;
 457                 char *ptr;
 458
 459                 fp = fopen(git_path("FETCH_HEAD"), "r");
 460                 if (!fp)
 461                         die_errno("could not open '%s' for reading",
 462                                   git_path("FETCH_HEAD"));
 463                 strbuf_getline(&line, fp, '\n');
 464                 fclose(fp);
 465                 ptr = strstr(line.buf, "\tnot-for-merge\t");
 466                 if (ptr)
 467                         strbuf_remove(&line, ptr-line.buf+1, 13);
 468                 strbuf_addbuf(msg, &line);
 469                 strbuf_release(&line);
 470                 goto cleanup;
 471         }
 472         strbuf_addf(msg, "%s\t\tcommit '%s'\n",
 473                 sha1_to_hex(remote_head->sha1), remote);
 474 cleanup:
 475         strbuf_release(&buf);
 476         strbuf_release(&bname);
 477 }
 478
 479 static int git_merge_config(const char *k, const char *v, void *cb)
 480 {
 481         if (branch && !prefixcmp(k, "branch.") &&
 482                 !prefixcmp(k + 7, branch) &&
 483                 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
 484                 const char **argv;
 485                 int argc;
 486                 char *buf;
 487
 488                 buf = xstrdup(v);
 489                 argc = split_cmdline(buf, &argv);
 490                 if (argc < 0)
 491                         die("Bad branch.%s.mergeoptions string: %s", branch,
 492                             split_cmdline_strerror(argc));
 493                 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
 494                 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
 495                 argc++;
 496                 parse_options(argc, argv, NULL, builtin_merge_options,
 497                               builtin_merge_usage, 0);
 498                 free(buf);
 499         }
 500
 501         if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
 502                 show_diffstat = git_config_bool(k, v);
 503         else if (!strcmp(k, "pull.twohead"))
 504                 return git_config_string(&pull_twohead, k, v);
 505         else if (!strcmp(k, "pull.octopus"))
 506                 return git_config_string(&pull_octopus, k, v);
 507         else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
 508                 option_log = git_config_bool(k, v);
 509         else if (!strcmp(k, "merge.renormalize"))
 510                 option_renormalize = git_config_bool(k, v);
 511         return git_diff_ui_config(k, v, cb);
 512 }
 513
 514 static int read_tree_trivial(unsigned char *common, unsigned char *head,
 515                              unsigned char *one)
 516 {
 517         int i, nr_trees = 0;
 518         struct tree *trees[MAX_UNPACK_TREES];
 519         struct tree_desc t[MAX_UNPACK_TREES];
 520         struct unpack_trees_options opts;
 521
 522         memset(&opts, 0, sizeof(opts));
 523         opts.head_idx = 2;
 524         opts.src_index = &the_index;
 525         opts.dst_index = &the_index;
 526         opts.update = 1;
 527         opts.verbose_update = 1;
 528         opts.trivial_merges_only = 1;
 529         opts.merge = 1;
 530         trees[nr_trees] = parse_tree_indirect(common);
 531         if (!trees[nr_trees++])
 532                 return -1;
 533         trees[nr_trees] = parse_tree_indirect(head);
 534         if (!trees[nr_trees++])
 535                 return -1;
 536         trees[nr_trees] = parse_tree_indirect(one);
 537         if (!trees[nr_trees++])
 538                 return -1;
 539         opts.fn = threeway_merge;
 540         cache_tree_free(&active_cache_tree);
 541         for (i = 0; i < nr_trees; i++) {
 542                 parse_tree(trees[i]);
 543                 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 544         }
 545         if (unpack_trees(nr_trees, t, &opts))
 546                 return -1;
 547         return 0;
 548 }
 549
 550 static void write_tree_trivial(unsigned char *sha1)
 551 {
 552         if (write_cache_as_tree(sha1, 0, NULL))
 553                 die("git write-tree failed to write a tree");
 554 }
 555
 556 int try_merge_command(const char *strategy, struct commit_list *common,
 557                       const char *head_arg, struct commit_list *remotes)
 558 {
 559         const char **args;
 560         int i = 0, x = 0, ret;
 561         struct commit_list *j;
 562         struct strbuf buf = STRBUF_INIT;
 563
 564         args = xmalloc((4 + xopts_nr + commit_list_count(common) +
 565                         commit_list_count(remotes)) * sizeof(char *));
 566         strbuf_addf(&buf, "merge-%s", strategy);
 567         args[i++] = buf.buf;
 568         for (x = 0; x < xopts_nr; x++) {
 569                 char *s = xmalloc(strlen(xopts[x])+2+1);
 570                 strcpy(s, "--");
 571                 strcpy(s+2, xopts[x]);
 572                 args[i++] = s;
 573         }
 574         for (j = common; j; j = j->next)
 575                 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
 576         args[i++] = "--";
 577         args[i++] = head_arg;
 578         for (j = remotes; j; j = j->next)
 579                 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
 580         args[i] = NULL;
 581         ret = run_command_v_opt(args, RUN_GIT_CMD);
 582         strbuf_release(&buf);
 583         i = 1;
 584         for (x = 0; x < xopts_nr; x++)
 585                 free((void *)args[i++]);
 586         for (j = common; j; j = j->next)
 587                 free((void *)args[i++]);
 588         i += 2;
 589         for (j = remotes; j; j = j->next)
 590                 free((void *)args[i++]);
 591         free(args);
 592         discard_cache();
 593         if (read_cache() < 0)
 594                 die("failed to read the cache");
 595         resolve_undo_clear();
 596
 597         return ret;
 598 }
 599
 600 static int try_merge_strategy(const char *strategy, struct commit_list *common,
 601                               const char *head_arg)
 602 {
 603         int index_fd;
 604         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 605
 606         index_fd = hold_locked_index(lock, 1);
 607         refresh_cache(REFRESH_QUIET);
 608         if (active_cache_changed &&
 609                         (write_cache(index_fd, active_cache, active_nr) ||
 610                          commit_locked_index(lock)))
 611                 return error("Unable to write index.");
 612         rollback_lock_file(lock);
 613
 614         if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
 615                 int clean, x;
 616                 struct commit *result;
 617                 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 618                 int index_fd;
 619                 struct commit_list *reversed = NULL;
 620                 struct merge_options o;
 621                 struct commit_list *j;
 622
 623                 if (remoteheads->next) {
 624                         error("Not handling anything other than two heads merge.");
 625                         return 2;
 626                 }
 627
 628                 init_merge_options(&o);
 629                 if (!strcmp(strategy, "subtree"))
 630                         o.subtree_shift = "";
 631
 632                 o.renormalize = option_renormalize;
 633
 634                 /*
 635                  * NEEDSWORK: merge with table in builtin/merge-recursive
 636                  */
 637                 for (x = 0; x < xopts_nr; x++) {
 638                         if (!strcmp(xopts[x], "ours"))
 639                                 o.recursive_variant = MERGE_RECURSIVE_OURS;
 640                         else if (!strcmp(xopts[x], "theirs"))
 641                                 o.recursive_variant = MERGE_RECURSIVE_THEIRS;
 642                         else if (!strcmp(xopts[x], "subtree"))
 643                                 o.subtree_shift = "";
 644                         else if (!prefixcmp(xopts[x], "subtree="))
 645                                 o.subtree_shift = xopts[x]+8;
 646                         else if (!strcmp(xopts[x], "renormalize"))
 647                                 o.renormalize = 1;
 648                         else if (!strcmp(xopts[x], "no-renormalize"))
 649                                 o.renormalize = 0;
 650                         else
 651                                 die("Unknown option for merge-recursive: -X%s", xopts[x]);
 652                 }
 653
 654                 o.branch1 = head_arg;
 655                 o.branch2 = remoteheads->item->util;
 656
 657                 for (j = common; j; j = j->next)
 658                         commit_list_insert(j->item, &reversed);
 659
 660                 index_fd = hold_locked_index(lock, 1);
 661                 clean = merge_recursive(&o, lookup_commit(head),
 662                                 remoteheads->item, reversed, &result);
 663                 if (active_cache_changed &&
 664                                 (write_cache(index_fd, active_cache, active_nr) ||
 665                                  commit_locked_index(lock)))
 666                         die ("unable to write %s", get_index_file());
 667                 rollback_lock_file(lock);
 668                 return clean ? 0 : 1;
 669         } else {
 670                 return try_merge_command(strategy, common, head_arg, remoteheads);
 671         }
 672 }
 673
 674 static void count_diff_files(struct diff_queue_struct *q,
 675                              struct diff_options *opt, void *data)
 676 {
 677         int *count = data;
 678
 679         (*count) += q->nr;
 680 }
 681
 682 static int count_unmerged_entries(void)
 683 {
 684         int i, ret = 0;
 685
 686         for (i = 0; i < active_nr; i++)
 687                 if (ce_stage(active_cache[i]))
 688                         ret++;
 689
 690         return ret;
 691 }
 692
 693 int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
 694 {
 695         struct tree *trees[MAX_UNPACK_TREES];
 696         struct unpack_trees_options opts;
 697         struct tree_desc t[MAX_UNPACK_TREES];
 698         int i, fd, nr_trees = 0;
 699         struct dir_struct dir;
 700         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 701
 702         refresh_cache(REFRESH_QUIET);
 703
 704         fd = hold_locked_index(lock_file, 1);
 705
 706         memset(&trees, 0, sizeof(trees));
 707         memset(&opts, 0, sizeof(opts));
 708         memset(&t, 0, sizeof(t));
 709         memset(&dir, 0, sizeof(dir));
 710         dir.flags |= DIR_SHOW_IGNORED;
 711         dir.exclude_per_dir = ".gitignore";
 712         opts.dir = &dir;
 713
 714         opts.head_idx = 1;
 715         opts.src_index = &the_index;
 716         opts.dst_index = &the_index;
 717         opts.update = 1;
 718         opts.verbose_update = 1;
 719         opts.merge = 1;
 720         opts.fn = twoway_merge;
 721         opts.show_all_errors = 1;
 722         set_porcelain_error_msgs(opts.msgs, "merge");
 723
 724         trees[nr_trees] = parse_tree_indirect(head);
 725         if (!trees[nr_trees++])
 726                 return -1;
 727         trees[nr_trees] = parse_tree_indirect(remote);
 728         if (!trees[nr_trees++])
 729                 return -1;
 730         for (i = 0; i < nr_trees; i++) {
 731                 parse_tree(trees[i]);
 732                 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 733         }
 734         if (unpack_trees(nr_trees, t, &opts))
 735                 return -1;
 736         if (write_cache(fd, active_cache, active_nr) ||
 737                 commit_locked_index(lock_file))
 738                 die("unable to write new index file");
 739         return 0;
 740 }
 741
 742 static void split_merge_strategies(const char *string, struct strategy **list,
 743                                    int *nr, int *alloc)
 744 {
 745         char *p, *q, *buf;
 746
 747         if (!string)
 748                 return;
 749
 750         buf = xstrdup(string);
 751         q = buf;
 752         for (;;) {
 753                 p = strchr(q, ' ');
 754                 if (!p) {
 755                         ALLOC_GROW(*list, *nr + 1, *alloc);
 756                         (*list)[(*nr)++].name = xstrdup(q);
 757                         free(buf);
 758                         return;
 759                 } else {
 760                         *p = '\0';
 761                         ALLOC_GROW(*list, *nr + 1, *alloc);
 762                         (*list)[(*nr)++].name = xstrdup(q);
 763                         q = ++p;
 764                 }
 765         }
 766 }
 767
 768 static void add_strategies(const char *string, unsigned attr)
 769 {
 770         struct strategy *list = NULL;
 771         int list_alloc = 0, list_nr = 0, i;
 772
 773         memset(&list, 0, sizeof(list));
 774         split_merge_strategies(string, &list, &list_nr, &list_alloc);
 775         if (list) {
 776                 for (i = 0; i < list_nr; i++)
 777                         append_strategy(get_strategy(list[i].name));
 778                 return;
 779         }
 780         for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
 781                 if (all_strategy[i].attr & attr)
 782                         append_strategy(&all_strategy[i]);
 783
 784 }
 785
 786 static int merge_trivial(void)
 787 {
 788         unsigned char result_tree[20], result_commit[20];
 789         struct commit_list *parent = xmalloc(sizeof(*parent));
 790
 791         write_tree_trivial(result_tree);
 792         printf("Wonderful.\n");
 793         parent->item = lookup_commit(head);
 794         parent->next = xmalloc(sizeof(*parent->next));
 795         parent->next->item = remoteheads->item;
 796         parent->next->next = NULL;
 797         commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
 798         finish(result_commit, "In-index merge");
 799         drop_save();
 800         return 0;
 801 }
 802
 803 static int finish_automerge(struct commit_list *common,
 804                             unsigned char *result_tree,
 805                             const char *wt_strategy)
 806 {
 807         struct commit_list *parents = NULL, *j;
 808         struct strbuf buf = STRBUF_INIT;
 809         unsigned char result_commit[20];
 810
 811         free_commit_list(common);
 812         if (allow_fast_forward) {
 813                 parents = remoteheads;
 814                 commit_list_insert(lookup_commit(head), &parents);
 815                 parents = reduce_heads(parents);
 816         } else {
 817                 struct commit_list **pptr = &parents;
 818
 819                 pptr = &commit_list_insert(lookup_commit(head),
 820                                 pptr)->next;
 821                 for (j = remoteheads; j; j = j->next)
 822                         pptr = &commit_list_insert(j->item, pptr)->next;
 823         }
 824         free_commit_list(remoteheads);
 825         strbuf_addch(&merge_msg, '\n');
 826         commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
 827         strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
 828         finish(result_commit, buf.buf);
 829         strbuf_release(&buf);
 830         drop_save();
 831         return 0;
 832 }
 833
 834 static int suggest_conflicts(int renormalizing)
 835 {
 836         FILE *fp;
 837         int pos;
 838
 839         fp = fopen(git_path("MERGE_MSG"), "a");
 840         if (!fp)
 841                 die_errno("Could not open '%s' for writing",
 842                           git_path("MERGE_MSG"));
 843         fprintf(fp, "\nConflicts:\n");
 844         for (pos = 0; pos < active_nr; pos++) {
 845                 struct cache_entry *ce = active_cache[pos];
 846
 847                 if (ce_stage(ce)) {
 848                         fprintf(fp, "\t%s\n", ce->name);
 849                         while (pos + 1 < active_nr &&
 850                                         !strcmp(ce->name,
 851                                                 active_cache[pos + 1]->name))
 852                                 pos++;
 853                 }
 854         }
 855         fclose(fp);
 856         rerere(allow_rerere_auto);
 857         printf("Automatic merge failed; "
 858                         "fix conflicts and then commit the result.\n");
 859         return 1;
 860 }
 861
 862 static struct commit *is_old_style_invocation(int argc, const char **argv)
 863 {
 864         struct commit *second_token = NULL;
 865         if (argc > 2) {
 866                 unsigned char second_sha1[20];
 867
 868                 if (get_sha1(argv[1], second_sha1))
 869                         return NULL;
 870                 second_token = lookup_commit_reference_gently(second_sha1, 0);
 871                 if (!second_token)
 872                         die("'%s' is not a commit", argv[1]);
 873                 if (hashcmp(second_token->object.sha1, head))
 874                         return NULL;
 875         }
 876         return second_token;
 877 }
 878
 879 static int evaluate_result(void)
 880 {
 881         int cnt = 0;
 882         struct rev_info rev;
 883
 884         /* Check how many files differ. */
 885         init_revisions(&rev, "");
 886         setup_revisions(0, NULL, &rev, NULL);
 887         rev.diffopt.output_format |=
 888                 DIFF_FORMAT_CALLBACK;
 889         rev.diffopt.format_callback = count_diff_files;
 890         rev.diffopt.format_callback_data = &cnt;
 891         run_diff_files(&rev, 0);
 892
 893         /*
 894          * Check how many unmerged entries are
 895          * there.
 896          */
 897         cnt += count_unmerged_entries();
 898
 899         return cnt;
 900 }
 901
 902 int cmd_merge(int argc, const char **argv, const char *prefix)
 903 {
 904         unsigned char result_tree[20];
 905         struct strbuf buf = STRBUF_INIT;
 906         const char *head_arg;
 907         int flag, head_invalid = 0, i;
 908         int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
 909         struct commit_list *common = NULL;
 910         const char *best_strategy = NULL, *wt_strategy = NULL;
 911         struct commit_list **remotes = &remoteheads;
 912
 913         if (read_cache_unmerged()) {
 914                 die_resolve_conflict("merge");
 915         }
 916         if (file_exists(git_path("MERGE_HEAD"))) {
 917                 /*
 918                  * There is no unmerged entry, don't advise 'git
 919                  * add/rm <file>', just 'git commit'.
 920                  */
 921                 if (advice_resolve_conflict)
 922                         die("You have not concluded your merge (MERGE_HEAD exists).\n"
 923                             "Please, commit your changes before you can merge.");
 924                 else
 925                         die("You have not concluded your merge (MERGE_HEAD exists).");
 926         }
 927
 928         resolve_undo_clear();
 929         /*
 930          * Check if we are _not_ on a detached HEAD, i.e. if there is a
 931          * current branch.
 932          */
 933         branch = resolve_ref("HEAD", head, 0, &flag);
 934         if (branch && !prefixcmp(branch, "refs/heads/"))
 935                 branch += 11;
 936         if (is_null_sha1(head))
 937                 head_invalid = 1;
 938
 939         git_config(git_merge_config, NULL);
 940
 941         /* for color.ui */
 942         if (diff_use_color_default == -1)
 943                 diff_use_color_default = git_use_color_default;
 944
 945         argc = parse_options(argc, argv, prefix, builtin_merge_options,
 946                         builtin_merge_usage, 0);
 947         if (verbosity < 0)
 948                 show_diffstat = 0;
 949
 950         if (squash) {
 951                 if (!allow_fast_forward)
 952                         die("You cannot combine --squash with --no-ff.");
 953                 option_commit = 0;
 954         }
 955
 956         if (!allow_fast_forward && fast_forward_only)
 957                 die("You cannot combine --no-ff with --ff-only.");
 958
 959         if (!argc)
 960                 usage_with_options(builtin_merge_usage,
 961                         builtin_merge_options);
 962
 963         /*
 964          * This could be traditional "merge <msg> HEAD <commit>..."  and
 965          * the way we can tell it is to see if the second token is HEAD,
 966          * but some people might have misused the interface and used a
 967          * committish that is the same as HEAD there instead.
 968          * Traditional format never would have "-m" so it is an
 969          * additional safety measure to check for it.
 970          */
 971
 972         if (!have_message && is_old_style_invocation(argc, argv)) {
 973                 strbuf_addstr(&merge_msg, argv[0]);
 974                 head_arg = argv[1];
 975                 argv += 2;
 976                 argc -= 2;
 977         } else if (head_invalid) {
 978                 struct object *remote_head;
 979                 /*
 980                  * If the merged head is a valid one there is no reason
 981                  * to forbid "git merge" into a branch yet to be born.
 982                  * We do the same for "git pull".
 983                  */
 984                 if (argc != 1)
 985                         die("Can merge only exactly one commit into "
 986                                 "empty head");
 987                 if (squash)
 988                         die("Squash commit into empty head not supported yet");
 989                 if (!allow_fast_forward)
 990                         die("Non-fast-forward commit does not make sense into "
 991                             "an empty head");
 992                 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
 993                 if (!remote_head)
 994                         die("%s - not something we can merge", argv[0]);
 995                 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
 996                                 DIE_ON_ERR);
 997                 reset_hard(remote_head->sha1, 0);
 998                 return 0;
 999         } else {
1000                 struct strbuf merge_names = STRBUF_INIT;
1001
1002                 /* We are invoked directly as the first-class UI. */
1003                 head_arg = "HEAD";
1004
1005                 /*
1006                  * All the rest are the commits being merged;
1007                  * prepare the standard merge summary message to
1008                  * be appended to the given message.  If remote
1009                  * is invalid we will die later in the common
1010                  * codepath so we discard the error in this
1011                  * loop.
1012                  */
1013                 for (i = 0; i < argc; i++)
1014                         merge_name(argv[i], &merge_names);
1015
1016                 if (have_message && option_log)
1017                         fmt_merge_msg_shortlog(&merge_names, &merge_msg);
1018                 else if (!have_message)
1019                         fmt_merge_msg(option_log, &merge_names, &merge_msg);
1020
1021
1022                 if (!(have_message && !option_log) && merge_msg.len)
1023                         strbuf_setlen(&merge_msg, merge_msg.len-1);
1024         }
1025
1026         if (head_invalid || !argc)
1027                 usage_with_options(builtin_merge_usage,
1028                         builtin_merge_options);
1029
1030         strbuf_addstr(&buf, "merge");
1031         for (i = 0; i < argc; i++)
1032                 strbuf_addf(&buf, " %s", argv[i]);
1033         setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1034         strbuf_reset(&buf);
1035
1036         for (i = 0; i < argc; i++) {
1037                 struct object *o;
1038                 struct commit *commit;
1039
1040                 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1041                 if (!o)
1042                         die("%s - not something we can merge", argv[i]);
1043                 commit = lookup_commit(o->sha1);
1044                 commit->util = (void *)argv[i];
1045                 remotes = &commit_list_insert(commit, remotes)->next;
1046
1047                 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1048                 setenv(buf.buf, argv[i], 1);
1049                 strbuf_reset(&buf);
1050         }
1051
1052         if (!use_strategies) {
1053                 if (!remoteheads->next)
1054                         add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1055                 else
1056                         add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1057         }
1058
1059         for (i = 0; i < use_strategies_nr; i++) {
1060                 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1061                         allow_fast_forward = 0;
1062                 if (use_strategies[i]->attr & NO_TRIVIAL)
1063                         allow_trivial = 0;
1064         }
1065
1066         if (!remoteheads->next)
1067                 common = get_merge_bases(lookup_commit(head),
1068                                 remoteheads->item, 1);
1069         else {
1070                 struct commit_list *list = remoteheads;
1071                 commit_list_insert(lookup_commit(head), &list);
1072                 common = get_octopus_merge_bases(list);
1073                 free(list);
1074         }
1075
1076         update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1077                 DIE_ON_ERR);
1078
1079         if (!common)
1080                 ; /* No common ancestors found. We need a real merge. */
1081         else if (!remoteheads->next && !common->next &&
1082                         common->item == remoteheads->item) {
1083                 /*
1084                  * If head can reach all the merge then we are up to date.
1085                  * but first the most common case of merging one remote.
1086                  */
1087                 finish_up_to_date("Already up-to-date.");
1088                 return 0;
1089         } else if (allow_fast_forward && !remoteheads->next &&
1090                         !common->next &&
1091                         !hashcmp(common->item->object.sha1, head)) {
1092                 /* Again the most common case of merging one remote. */
1093                 struct strbuf msg = STRBUF_INIT;
1094                 struct object *o;
1095                 char hex[41];
1096
1097                 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1098
1099                 if (verbosity >= 0)
1100                         printf("Updating %s..%s\n",
1101                                 hex,
1102                                 find_unique_abbrev(remoteheads->item->object.sha1,
1103                                 DEFAULT_ABBREV));
1104                 strbuf_addstr(&msg, "Fast-forward");
1105                 if (have_message)
1106                         strbuf_addstr(&msg,
1107                                 " (no commit created; -m option ignored)");
1108                 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1109                         0, NULL, OBJ_COMMIT);
1110                 if (!o)
1111                         return 1;
1112
1113                 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1114                         return 1;
1115
1116                 finish(o->sha1, msg.buf);
1117                 drop_save();
1118                 return 0;
1119         } else if (!remoteheads->next && common->next)
1120                 ;
1121                 /*
1122                  * We are not doing octopus and not fast-forward.  Need
1123                  * a real merge.
1124                  */
1125         else if (!remoteheads->next && !common->next && option_commit) {
1126                 /*
1127                  * We are not doing octopus, not fast-forward, and have
1128                  * only one common.
1129                  */
1130                 refresh_cache(REFRESH_QUIET);
1131                 if (allow_trivial && !fast_forward_only) {
1132                         /* See if it is really trivial. */
1133                         git_committer_info(IDENT_ERROR_ON_NO_NAME);
1134                         printf("Trying really trivial in-index merge...\n");
1135                         if (!read_tree_trivial(common->item->object.sha1,
1136                                         head, remoteheads->item->object.sha1))
1137                                 return merge_trivial();
1138                         printf("Nope.\n");
1139                 }
1140         } else {
1141                 /*
1142                  * An octopus.  If we can reach all the remote we are up
1143                  * to date.
1144                  */
1145                 int up_to_date = 1;
1146                 struct commit_list *j;
1147
1148                 for (j = remoteheads; j; j = j->next) {
1149                         struct commit_list *common_one;
1150
1151                         /*
1152                          * Here we *have* to calculate the individual
1153                          * merge_bases again, otherwise "git merge HEAD^
1154                          * HEAD^^" would be missed.
1155                          */
1156                         common_one = get_merge_bases(lookup_commit(head),
1157                                 j->item, 1);
1158                         if (hashcmp(common_one->item->object.sha1,
1159                                 j->item->object.sha1)) {
1160                                 up_to_date = 0;
1161                                 break;
1162                         }
1163                 }
1164                 if (up_to_date) {
1165                         finish_up_to_date("Already up-to-date. Yeeah!");
1166                         return 0;
1167                 }
1168         }
1169
1170         if (fast_forward_only)
1171                 die("Not possible to fast-forward, aborting.");
1172
1173         /* We are going to make a new commit. */
1174         git_committer_info(IDENT_ERROR_ON_NO_NAME);
1175
1176         /*
1177          * At this point, we need a real merge.  No matter what strategy
1178          * we use, it would operate on the index, possibly affecting the
1179          * working tree, and when resolved cleanly, have the desired
1180          * tree in the index -- this means that the index must be in
1181          * sync with the head commit.  The strategies are responsible
1182          * to ensure this.
1183          */
1184         if (use_strategies_nr != 1) {
1185                 /*
1186                  * Stash away the local changes so that we can try more
1187                  * than one.
1188                  */
1189                 save_state();
1190         } else {
1191                 memcpy(stash, null_sha1, 20);
1192         }
1193
1194         for (i = 0; i < use_strategies_nr; i++) {
1195                 int ret;
1196                 if (i) {
1197                         printf("Rewinding the tree to pristine...\n");
1198                         restore_state();
1199                 }
1200                 if (use_strategies_nr != 1)
1201                         printf("Trying merge strategy %s...\n",
1202                                 use_strategies[i]->name);
1203                 /*
1204                  * Remember which strategy left the state in the working
1205                  * tree.
1206                  */
1207                 wt_strategy = use_strategies[i]->name;
1208
1209                 ret = try_merge_strategy(use_strategies[i]->name,
1210                         common, head_arg);
1211                 if (!option_commit && !ret) {
1212                         merge_was_ok = 1;
1213                         /*
1214                          * This is necessary here just to avoid writing
1215                          * the tree, but later we will *not* exit with
1216                          * status code 1 because merge_was_ok is set.
1217                          */
1218                         ret = 1;
1219                 }
1220
1221                 if (ret) {
1222                         /*
1223                          * The backend exits with 1 when conflicts are
1224                          * left to be resolved, with 2 when it does not
1225                          * handle the given merge at all.
1226                          */
1227                         if (ret == 1) {
1228                                 int cnt = evaluate_result();
1229
1230                                 if (best_cnt <= 0 || cnt <= best_cnt) {
1231                                         best_strategy = use_strategies[i]->name;
1232                                         best_cnt = cnt;
1233                                 }
1234                         }
1235                         if (merge_was_ok)
1236                                 break;
1237                         else
1238                                 continue;
1239                 }
1240
1241                 /* Automerge succeeded. */
1242                 write_tree_trivial(result_tree);
1243                 automerge_was_ok = 1;
1244                 break;
1245         }
1246
1247         /*
1248          * If we have a resulting tree, that means the strategy module
1249          * auto resolved the merge cleanly.
1250          */
1251         if (automerge_was_ok)
1252                 return finish_automerge(common, result_tree, wt_strategy);
1253
1254         /*
1255          * Pick the result from the best strategy and have the user fix
1256          * it up.
1257          */
1258         if (!best_strategy) {
1259                 restore_state();
1260                 if (use_strategies_nr > 1)
1261                         fprintf(stderr,
1262                                 "No merge strategy handled the merge.\n");
1263                 else
1264                         fprintf(stderr, "Merge with strategy %s failed.\n",
1265                                 use_strategies[0]->name);
1266                 return 2;
1267         } else if (best_strategy == wt_strategy)
1268                 ; /* We already have its result in the working tree. */
1269         else {
1270                 printf("Rewinding the tree to pristine...\n");
1271                 restore_state();
1272                 printf("Using the %s to prepare resolving by hand.\n",
1273                         best_strategy);
1274                 try_merge_strategy(best_strategy, common, head_arg);
1275         }
1276
1277         if (squash)
1278                 finish(NULL, NULL);
1279         else {
1280                 int fd;
1281                 struct commit_list *j;
1282
1283                 for (j = remoteheads; j; j = j->next)
1284                         strbuf_addf(&buf, "%s\n",
1285                                 sha1_to_hex(j->item->object.sha1));
1286                 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1287                 if (fd < 0)
1288                         die_errno("Could not open '%s' for writing",
1289                                   git_path("MERGE_HEAD"));
1290                 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1291                         die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1292                 close(fd);
1293                 strbuf_addch(&merge_msg, '\n');
1294                 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1295                 if (fd < 0)
1296                         die_errno("Could not open '%s' for writing",
1297                                   git_path("MERGE_MSG"));
1298                 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1299                         merge_msg.len)
1300                         die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1301                 close(fd);
1302                 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1303                 if (fd < 0)
1304                         die_errno("Could not open '%s' for writing",
1305                                   git_path("MERGE_MODE"));
1306                 strbuf_reset(&buf);
1307                 if (!allow_fast_forward)
1308                         strbuf_addf(&buf, "no-ff");
1309                 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1310                         die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1311                 close(fd);
1312         }
1313
1314         if (merge_was_ok) {
1315                 fprintf(stderr, "Automatic merge went well; "
1316                         "stopped before committing as requested\n");
1317                 return 0;
1318         } else
1319                 return suggest_conflicts(option_renormalize);
1320 }