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