builtin / merge.con commit Merge branch 'rj/maint-test-fixes' into maint (f8d0215)
   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
  34struct strategy {
  35        const char *name;
  36        unsigned attr;
  37};
  38
  39static const char * const builtin_merge_usage[] = {
  40        "git merge [options] <remote>...",
  41        "git merge [options] <msg> HEAD <remote>",
  42        NULL
  43};
  44
  45static int show_diffstat = 1, option_log, squash;
  46static int option_commit = 1, allow_fast_forward = 1;
  47static int fast_forward_only;
  48static int allow_trivial = 1, have_message;
  49static struct strbuf merge_msg;
  50static struct commit_list *remoteheads;
  51static unsigned char head[20], stash[20];
  52static struct strategy **use_strategies;
  53static size_t use_strategies_nr, use_strategies_alloc;
  54static const char **xopts;
  55static size_t xopts_nr, xopts_alloc;
  56static const char *branch;
  57static int option_renormalize;
  58static int verbosity;
  59static int allow_rerere_auto;
  60
  61static 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
  69static const char *pull_twohead, *pull_octopus;
  70
  71static 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
  86static 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
 139static 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
 145static 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
 155static 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
 166static int option_parse_n(const struct option *opt,
 167                          const char *arg, int unset)
 168{
 169        show_diffstat = unset;
 170        return 0;
 171}
 172
 173static 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. */
 203static 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
 210static 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
 236static void read_empty(unsigned const char *sha1, int verbose)
 237{
 238        int i = 0;
 239        const char *args[7];
 240
 241        args[i++] = "read-tree";
 242        if (verbose)
 243                args[i++] = "-v";
 244        args[i++] = "-m";
 245        args[i++] = "-u";
 246        args[i++] = EMPTY_TREE_SHA1_HEX;
 247        args[i++] = sha1_to_hex(sha1);
 248        args[i] = NULL;
 249
 250        if (run_command_v_opt(args, RUN_GIT_CMD))
 251                die("read-tree failed");
 252}
 253
 254static void reset_hard(unsigned const char *sha1, int verbose)
 255{
 256        int i = 0;
 257        const char *args[6];
 258
 259        args[i++] = "read-tree";
 260        if (verbose)
 261                args[i++] = "-v";
 262        args[i++] = "--reset";
 263        args[i++] = "-u";
 264        args[i++] = sha1_to_hex(sha1);
 265        args[i] = NULL;
 266
 267        if (run_command_v_opt(args, RUN_GIT_CMD))
 268                die("read-tree failed");
 269}
 270
 271static void restore_state(void)
 272{
 273        struct strbuf sb = STRBUF_INIT;
 274        const char *args[] = { "stash", "apply", NULL, NULL };
 275
 276        if (is_null_sha1(stash))
 277                return;
 278
 279        reset_hard(head, 1);
 280
 281        args[2] = sha1_to_hex(stash);
 282
 283        /*
 284         * It is OK to ignore error here, for example when there was
 285         * nothing to restore.
 286         */
 287        run_command_v_opt(args, RUN_GIT_CMD);
 288
 289        strbuf_release(&sb);
 290        refresh_cache(REFRESH_QUIET);
 291}
 292
 293/* This is called when no merge was necessary. */
 294static void finish_up_to_date(const char *msg)
 295{
 296        if (verbosity >= 0)
 297                printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
 298        drop_save();
 299}
 300
 301static void squash_message(void)
 302{
 303        struct rev_info rev;
 304        struct commit *commit;
 305        struct strbuf out = STRBUF_INIT;
 306        struct commit_list *j;
 307        int fd;
 308        struct pretty_print_context ctx = {0};
 309
 310        printf("Squash commit -- not updating HEAD\n");
 311        fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
 312        if (fd < 0)
 313                die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
 314
 315        init_revisions(&rev, NULL);
 316        rev.ignore_merges = 1;
 317        rev.commit_format = CMIT_FMT_MEDIUM;
 318
 319        commit = lookup_commit(head);
 320        commit->object.flags |= UNINTERESTING;
 321        add_pending_object(&rev, &commit->object, NULL);
 322
 323        for (j = remoteheads; j; j = j->next)
 324                add_pending_object(&rev, &j->item->object, NULL);
 325
 326        setup_revisions(0, NULL, &rev, NULL);
 327        if (prepare_revision_walk(&rev))
 328                die("revision walk setup failed");
 329
 330        ctx.abbrev = rev.abbrev;
 331        ctx.date_mode = rev.date_mode;
 332
 333        strbuf_addstr(&out, "Squashed commit of the following:\n");
 334        while ((commit = get_revision(&rev)) != NULL) {
 335                strbuf_addch(&out, '\n');
 336                strbuf_addf(&out, "commit %s\n",
 337                        sha1_to_hex(commit->object.sha1));
 338                pretty_print_commit(rev.commit_format, commit, &out, &ctx);
 339        }
 340        if (write(fd, out.buf, out.len) < 0)
 341                die_errno("Writing SQUASH_MSG");
 342        if (close(fd))
 343                die_errno("Finishing SQUASH_MSG");
 344        strbuf_release(&out);
 345}
 346
 347static void finish(const unsigned char *new_head, const char *msg)
 348{
 349        struct strbuf reflog_message = STRBUF_INIT;
 350
 351        if (!msg)
 352                strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
 353        else {
 354                if (verbosity >= 0)
 355                        printf("%s\n", msg);
 356                strbuf_addf(&reflog_message, "%s: %s",
 357                        getenv("GIT_REFLOG_ACTION"), msg);
 358        }
 359        if (squash) {
 360                squash_message();
 361        } else {
 362                if (verbosity >= 0 && !merge_msg.len)
 363                        printf("No merge message -- not updating HEAD\n");
 364                else {
 365                        const char *argv_gc_auto[] = { "gc", "--auto", NULL };
 366                        update_ref(reflog_message.buf, "HEAD",
 367                                new_head, head, 0,
 368                                DIE_ON_ERR);
 369                        /*
 370                         * We ignore errors in 'gc --auto', since the
 371                         * user should see them.
 372                         */
 373                        run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
 374                }
 375        }
 376        if (new_head && show_diffstat) {
 377                struct diff_options opts;
 378                diff_setup(&opts);
 379                opts.output_format |=
 380                        DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
 381                opts.detect_rename = DIFF_DETECT_RENAME;
 382                if (diff_use_color_default > 0)
 383                        DIFF_OPT_SET(&opts, COLOR_DIFF);
 384                if (diff_setup_done(&opts) < 0)
 385                        die("diff_setup_done failed");
 386                diff_tree_sha1(head, new_head, "", &opts);
 387                diffcore_std(&opts);
 388                diff_flush(&opts);
 389        }
 390
 391        /* Run a post-merge hook */
 392        run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
 393
 394        strbuf_release(&reflog_message);
 395}
 396
 397/* Get the name for the merge commit's message. */
 398static void merge_name(const char *remote, struct strbuf *msg)
 399{
 400        struct object *remote_head;
 401        unsigned char branch_head[20], buf_sha[20];
 402        struct strbuf buf = STRBUF_INIT;
 403        struct strbuf bname = STRBUF_INIT;
 404        const char *ptr;
 405        char *found_ref;
 406        int len, early;
 407
 408        strbuf_branchname(&bname, remote);
 409        remote = bname.buf;
 410
 411        memset(branch_head, 0, sizeof(branch_head));
 412        remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
 413        if (!remote_head)
 414                die("'%s' does not point to a commit", remote);
 415
 416        if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
 417                if (!prefixcmp(found_ref, "refs/heads/")) {
 418                        strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
 419                                    sha1_to_hex(branch_head), remote);
 420                        goto cleanup;
 421                }
 422                if (!prefixcmp(found_ref, "refs/remotes/")) {
 423                        strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
 424                                    sha1_to_hex(branch_head), remote);
 425                        goto cleanup;
 426                }
 427        }
 428
 429        /* See if remote matches <name>^^^.. or <name>~<number> */
 430        for (len = 0, ptr = remote + strlen(remote);
 431             remote < ptr && ptr[-1] == '^';
 432             ptr--)
 433                len++;
 434        if (len)
 435                early = 1;
 436        else {
 437                early = 0;
 438                ptr = strrchr(remote, '~');
 439                if (ptr) {
 440                        int seen_nonzero = 0;
 441
 442                        len++; /* count ~ */
 443                        while (*++ptr && isdigit(*ptr)) {
 444                                seen_nonzero |= (*ptr != '0');
 445                                len++;
 446                        }
 447                        if (*ptr)
 448                                len = 0; /* not ...~<number> */
 449                        else if (seen_nonzero)
 450                                early = 1;
 451                        else if (len == 1)
 452                                early = 1; /* "name~" is "name~1"! */
 453                }
 454        }
 455        if (len) {
 456                struct strbuf truname = STRBUF_INIT;
 457                strbuf_addstr(&truname, "refs/heads/");
 458                strbuf_addstr(&truname, remote);
 459                strbuf_setlen(&truname, truname.len - len);
 460                if (resolve_ref(truname.buf, buf_sha, 1, NULL)) {
 461                        strbuf_addf(msg,
 462                                    "%s\t\tbranch '%s'%s of .\n",
 463                                    sha1_to_hex(remote_head->sha1),
 464                                    truname.buf + 11,
 465                                    (early ? " (early part)" : ""));
 466                        strbuf_release(&truname);
 467                        goto cleanup;
 468                }
 469        }
 470
 471        if (!strcmp(remote, "FETCH_HEAD") &&
 472                        !access(git_path("FETCH_HEAD"), R_OK)) {
 473                FILE *fp;
 474                struct strbuf line = STRBUF_INIT;
 475                char *ptr;
 476
 477                fp = fopen(git_path("FETCH_HEAD"), "r");
 478                if (!fp)
 479                        die_errno("could not open '%s' for reading",
 480                                  git_path("FETCH_HEAD"));
 481                strbuf_getline(&line, fp, '\n');
 482                fclose(fp);
 483                ptr = strstr(line.buf, "\tnot-for-merge\t");
 484                if (ptr)
 485                        strbuf_remove(&line, ptr-line.buf+1, 13);
 486                strbuf_addbuf(msg, &line);
 487                strbuf_release(&line);
 488                goto cleanup;
 489        }
 490        strbuf_addf(msg, "%s\t\tcommit '%s'\n",
 491                sha1_to_hex(remote_head->sha1), remote);
 492cleanup:
 493        strbuf_release(&buf);
 494        strbuf_release(&bname);
 495}
 496
 497static int git_merge_config(const char *k, const char *v, void *cb)
 498{
 499        if (branch && !prefixcmp(k, "branch.") &&
 500                !prefixcmp(k + 7, branch) &&
 501                !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
 502                const char **argv;
 503                int argc;
 504                char *buf;
 505
 506                buf = xstrdup(v);
 507                argc = split_cmdline(buf, &argv);
 508                if (argc < 0)
 509                        die("Bad branch.%s.mergeoptions string: %s", branch,
 510                            split_cmdline_strerror(argc));
 511                argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
 512                memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
 513                argc++;
 514                parse_options(argc, argv, NULL, builtin_merge_options,
 515                              builtin_merge_usage, 0);
 516                free(buf);
 517        }
 518
 519        if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
 520                show_diffstat = git_config_bool(k, v);
 521        else if (!strcmp(k, "pull.twohead"))
 522                return git_config_string(&pull_twohead, k, v);
 523        else if (!strcmp(k, "pull.octopus"))
 524                return git_config_string(&pull_octopus, k, v);
 525        else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
 526                option_log = git_config_bool(k, v);
 527        else if (!strcmp(k, "merge.renormalize"))
 528                option_renormalize = git_config_bool(k, v);
 529        return git_diff_ui_config(k, v, cb);
 530}
 531
 532static int read_tree_trivial(unsigned char *common, unsigned char *head,
 533                             unsigned char *one)
 534{
 535        int i, nr_trees = 0;
 536        struct tree *trees[MAX_UNPACK_TREES];
 537        struct tree_desc t[MAX_UNPACK_TREES];
 538        struct unpack_trees_options opts;
 539
 540        memset(&opts, 0, sizeof(opts));
 541        opts.head_idx = 2;
 542        opts.src_index = &the_index;
 543        opts.dst_index = &the_index;
 544        opts.update = 1;
 545        opts.verbose_update = 1;
 546        opts.trivial_merges_only = 1;
 547        opts.merge = 1;
 548        trees[nr_trees] = parse_tree_indirect(common);
 549        if (!trees[nr_trees++])
 550                return -1;
 551        trees[nr_trees] = parse_tree_indirect(head);
 552        if (!trees[nr_trees++])
 553                return -1;
 554        trees[nr_trees] = parse_tree_indirect(one);
 555        if (!trees[nr_trees++])
 556                return -1;
 557        opts.fn = threeway_merge;
 558        cache_tree_free(&active_cache_tree);
 559        for (i = 0; i < nr_trees; i++) {
 560                parse_tree(trees[i]);
 561                init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 562        }
 563        if (unpack_trees(nr_trees, t, &opts))
 564                return -1;
 565        return 0;
 566}
 567
 568static void write_tree_trivial(unsigned char *sha1)
 569{
 570        if (write_cache_as_tree(sha1, 0, NULL))
 571                die("git write-tree failed to write a tree");
 572}
 573
 574int try_merge_command(const char *strategy, struct commit_list *common,
 575                      const char *head_arg, struct commit_list *remotes)
 576{
 577        const char **args;
 578        int i = 0, x = 0, ret;
 579        struct commit_list *j;
 580        struct strbuf buf = STRBUF_INIT;
 581
 582        args = xmalloc((4 + xopts_nr + commit_list_count(common) +
 583                        commit_list_count(remotes)) * sizeof(char *));
 584        strbuf_addf(&buf, "merge-%s", strategy);
 585        args[i++] = buf.buf;
 586        for (x = 0; x < xopts_nr; x++) {
 587                char *s = xmalloc(strlen(xopts[x])+2+1);
 588                strcpy(s, "--");
 589                strcpy(s+2, xopts[x]);
 590                args[i++] = s;
 591        }
 592        for (j = common; j; j = j->next)
 593                args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
 594        args[i++] = "--";
 595        args[i++] = head_arg;
 596        for (j = remotes; j; j = j->next)
 597                args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
 598        args[i] = NULL;
 599        ret = run_command_v_opt(args, RUN_GIT_CMD);
 600        strbuf_release(&buf);
 601        i = 1;
 602        for (x = 0; x < xopts_nr; x++)
 603                free((void *)args[i++]);
 604        for (j = common; j; j = j->next)
 605                free((void *)args[i++]);
 606        i += 2;
 607        for (j = remotes; j; j = j->next)
 608                free((void *)args[i++]);
 609        free(args);
 610        discard_cache();
 611        if (read_cache() < 0)
 612                die("failed to read the cache");
 613        resolve_undo_clear();
 614
 615        return ret;
 616}
 617
 618static int try_merge_strategy(const char *strategy, struct commit_list *common,
 619                              const char *head_arg)
 620{
 621        int index_fd;
 622        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 623
 624        index_fd = hold_locked_index(lock, 1);
 625        refresh_cache(REFRESH_QUIET);
 626        if (active_cache_changed &&
 627                        (write_cache(index_fd, active_cache, active_nr) ||
 628                         commit_locked_index(lock)))
 629                return error("Unable to write index.");
 630        rollback_lock_file(lock);
 631
 632        if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
 633                int clean, x;
 634                struct commit *result;
 635                struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
 636                int index_fd;
 637                struct commit_list *reversed = NULL;
 638                struct merge_options o;
 639                struct commit_list *j;
 640
 641                if (remoteheads->next) {
 642                        error("Not handling anything other than two heads merge.");
 643                        return 2;
 644                }
 645
 646                init_merge_options(&o);
 647                if (!strcmp(strategy, "subtree"))
 648                        o.subtree_shift = "";
 649
 650                o.renormalize = option_renormalize;
 651
 652                /*
 653                 * NEEDSWORK: merge with table in builtin/merge-recursive
 654                 */
 655                for (x = 0; x < xopts_nr; x++) {
 656                        if (!strcmp(xopts[x], "ours"))
 657                                o.recursive_variant = MERGE_RECURSIVE_OURS;
 658                        else if (!strcmp(xopts[x], "theirs"))
 659                                o.recursive_variant = MERGE_RECURSIVE_THEIRS;
 660                        else if (!strcmp(xopts[x], "subtree"))
 661                                o.subtree_shift = "";
 662                        else if (!prefixcmp(xopts[x], "subtree="))
 663                                o.subtree_shift = xopts[x]+8;
 664                        else if (!strcmp(xopts[x], "renormalize"))
 665                                o.renormalize = 1;
 666                        else if (!strcmp(xopts[x], "no-renormalize"))
 667                                o.renormalize = 0;
 668                        else
 669                                die("Unknown option for merge-recursive: -X%s", xopts[x]);
 670                }
 671
 672                o.branch1 = head_arg;
 673                o.branch2 = remoteheads->item->util;
 674
 675                for (j = common; j; j = j->next)
 676                        commit_list_insert(j->item, &reversed);
 677
 678                index_fd = hold_locked_index(lock, 1);
 679                clean = merge_recursive(&o, lookup_commit(head),
 680                                remoteheads->item, reversed, &result);
 681                if (active_cache_changed &&
 682                                (write_cache(index_fd, active_cache, active_nr) ||
 683                                 commit_locked_index(lock)))
 684                        die ("unable to write %s", get_index_file());
 685                rollback_lock_file(lock);
 686                return clean ? 0 : 1;
 687        } else {
 688                return try_merge_command(strategy, common, head_arg, remoteheads);
 689        }
 690}
 691
 692static void count_diff_files(struct diff_queue_struct *q,
 693                             struct diff_options *opt, void *data)
 694{
 695        int *count = data;
 696
 697        (*count) += q->nr;
 698}
 699
 700static int count_unmerged_entries(void)
 701{
 702        int i, ret = 0;
 703
 704        for (i = 0; i < active_nr; i++)
 705                if (ce_stage(active_cache[i]))
 706                        ret++;
 707
 708        return ret;
 709}
 710
 711int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
 712{
 713        struct tree *trees[MAX_UNPACK_TREES];
 714        struct unpack_trees_options opts;
 715        struct tree_desc t[MAX_UNPACK_TREES];
 716        int i, fd, nr_trees = 0;
 717        struct dir_struct dir;
 718        struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 719
 720        refresh_cache(REFRESH_QUIET);
 721
 722        fd = hold_locked_index(lock_file, 1);
 723
 724        memset(&trees, 0, sizeof(trees));
 725        memset(&opts, 0, sizeof(opts));
 726        memset(&t, 0, sizeof(t));
 727        memset(&dir, 0, sizeof(dir));
 728        dir.flags |= DIR_SHOW_IGNORED;
 729        dir.exclude_per_dir = ".gitignore";
 730        opts.dir = &dir;
 731
 732        opts.head_idx = 1;
 733        opts.src_index = &the_index;
 734        opts.dst_index = &the_index;
 735        opts.update = 1;
 736        opts.verbose_update = 1;
 737        opts.merge = 1;
 738        opts.fn = twoway_merge;
 739        setup_unpack_trees_porcelain(&opts, "merge");
 740
 741        trees[nr_trees] = parse_tree_indirect(head);
 742        if (!trees[nr_trees++])
 743                return -1;
 744        trees[nr_trees] = parse_tree_indirect(remote);
 745        if (!trees[nr_trees++])
 746                return -1;
 747        for (i = 0; i < nr_trees; i++) {
 748                parse_tree(trees[i]);
 749                init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
 750        }
 751        if (unpack_trees(nr_trees, t, &opts))
 752                return -1;
 753        if (write_cache(fd, active_cache, active_nr) ||
 754                commit_locked_index(lock_file))
 755                die("unable to write new index file");
 756        return 0;
 757}
 758
 759static void split_merge_strategies(const char *string, struct strategy **list,
 760                                   int *nr, int *alloc)
 761{
 762        char *p, *q, *buf;
 763
 764        if (!string)
 765                return;
 766
 767        buf = xstrdup(string);
 768        q = buf;
 769        for (;;) {
 770                p = strchr(q, ' ');
 771                if (!p) {
 772                        ALLOC_GROW(*list, *nr + 1, *alloc);
 773                        (*list)[(*nr)++].name = xstrdup(q);
 774                        free(buf);
 775                        return;
 776                } else {
 777                        *p = '\0';
 778                        ALLOC_GROW(*list, *nr + 1, *alloc);
 779                        (*list)[(*nr)++].name = xstrdup(q);
 780                        q = ++p;
 781                }
 782        }
 783}
 784
 785static void add_strategies(const char *string, unsigned attr)
 786{
 787        struct strategy *list = NULL;
 788        int list_alloc = 0, list_nr = 0, i;
 789
 790        memset(&list, 0, sizeof(list));
 791        split_merge_strategies(string, &list, &list_nr, &list_alloc);
 792        if (list) {
 793                for (i = 0; i < list_nr; i++)
 794                        append_strategy(get_strategy(list[i].name));
 795                return;
 796        }
 797        for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
 798                if (all_strategy[i].attr & attr)
 799                        append_strategy(&all_strategy[i]);
 800
 801}
 802
 803static int merge_trivial(void)
 804{
 805        unsigned char result_tree[20], result_commit[20];
 806        struct commit_list *parent = xmalloc(sizeof(*parent));
 807
 808        write_tree_trivial(result_tree);
 809        printf("Wonderful.\n");
 810        parent->item = lookup_commit(head);
 811        parent->next = xmalloc(sizeof(*parent->next));
 812        parent->next->item = remoteheads->item;
 813        parent->next->next = NULL;
 814        commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
 815        finish(result_commit, "In-index merge");
 816        drop_save();
 817        return 0;
 818}
 819
 820static int finish_automerge(struct commit_list *common,
 821                            unsigned char *result_tree,
 822                            const char *wt_strategy)
 823{
 824        struct commit_list *parents = NULL, *j;
 825        struct strbuf buf = STRBUF_INIT;
 826        unsigned char result_commit[20];
 827
 828        free_commit_list(common);
 829        if (allow_fast_forward) {
 830                parents = remoteheads;
 831                commit_list_insert(lookup_commit(head), &parents);
 832                parents = reduce_heads(parents);
 833        } else {
 834                struct commit_list **pptr = &parents;
 835
 836                pptr = &commit_list_insert(lookup_commit(head),
 837                                pptr)->next;
 838                for (j = remoteheads; j; j = j->next)
 839                        pptr = &commit_list_insert(j->item, pptr)->next;
 840        }
 841        free_commit_list(remoteheads);
 842        strbuf_addch(&merge_msg, '\n');
 843        commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
 844        strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
 845        finish(result_commit, buf.buf);
 846        strbuf_release(&buf);
 847        drop_save();
 848        return 0;
 849}
 850
 851static int suggest_conflicts(int renormalizing)
 852{
 853        FILE *fp;
 854        int pos;
 855
 856        fp = fopen(git_path("MERGE_MSG"), "a");
 857        if (!fp)
 858                die_errno("Could not open '%s' for writing",
 859                          git_path("MERGE_MSG"));
 860        fprintf(fp, "\nConflicts:\n");
 861        for (pos = 0; pos < active_nr; pos++) {
 862                struct cache_entry *ce = active_cache[pos];
 863
 864                if (ce_stage(ce)) {
 865                        fprintf(fp, "\t%s\n", ce->name);
 866                        while (pos + 1 < active_nr &&
 867                                        !strcmp(ce->name,
 868                                                active_cache[pos + 1]->name))
 869                                pos++;
 870                }
 871        }
 872        fclose(fp);
 873        rerere(allow_rerere_auto);
 874        printf("Automatic merge failed; "
 875                        "fix conflicts and then commit the result.\n");
 876        return 1;
 877}
 878
 879static struct commit *is_old_style_invocation(int argc, const char **argv)
 880{
 881        struct commit *second_token = NULL;
 882        if (argc > 2) {
 883                unsigned char second_sha1[20];
 884
 885                if (get_sha1(argv[1], second_sha1))
 886                        return NULL;
 887                second_token = lookup_commit_reference_gently(second_sha1, 0);
 888                if (!second_token)
 889                        die("'%s' is not a commit", argv[1]);
 890                if (hashcmp(second_token->object.sha1, head))
 891                        return NULL;
 892        }
 893        return second_token;
 894}
 895
 896static int evaluate_result(void)
 897{
 898        int cnt = 0;
 899        struct rev_info rev;
 900
 901        /* Check how many files differ. */
 902        init_revisions(&rev, "");
 903        setup_revisions(0, NULL, &rev, NULL);
 904        rev.diffopt.output_format |=
 905                DIFF_FORMAT_CALLBACK;
 906        rev.diffopt.format_callback = count_diff_files;
 907        rev.diffopt.format_callback_data = &cnt;
 908        run_diff_files(&rev, 0);
 909
 910        /*
 911         * Check how many unmerged entries are
 912         * there.
 913         */
 914        cnt += count_unmerged_entries();
 915
 916        return cnt;
 917}
 918
 919int cmd_merge(int argc, const char **argv, const char *prefix)
 920{
 921        unsigned char result_tree[20];
 922        struct strbuf buf = STRBUF_INIT;
 923        const char *head_arg;
 924        int flag, head_invalid = 0, i;
 925        int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
 926        struct commit_list *common = NULL;
 927        const char *best_strategy = NULL, *wt_strategy = NULL;
 928        struct commit_list **remotes = &remoteheads;
 929
 930        if (read_cache_unmerged()) {
 931                die_resolve_conflict("merge");
 932        }
 933        if (file_exists(git_path("MERGE_HEAD"))) {
 934                /*
 935                 * There is no unmerged entry, don't advise 'git
 936                 * add/rm <file>', just 'git commit'.
 937                 */
 938                if (advice_resolve_conflict)
 939                        die("You have not concluded your merge (MERGE_HEAD exists).\n"
 940                            "Please, commit your changes before you can merge.");
 941                else
 942                        die("You have not concluded your merge (MERGE_HEAD exists).");
 943        }
 944
 945        resolve_undo_clear();
 946        /*
 947         * Check if we are _not_ on a detached HEAD, i.e. if there is a
 948         * current branch.
 949         */
 950        branch = resolve_ref("HEAD", head, 0, &flag);
 951        if (branch && !prefixcmp(branch, "refs/heads/"))
 952                branch += 11;
 953        if (is_null_sha1(head))
 954                head_invalid = 1;
 955
 956        git_config(git_merge_config, NULL);
 957
 958        /* for color.ui */
 959        if (diff_use_color_default == -1)
 960                diff_use_color_default = git_use_color_default;
 961
 962        argc = parse_options(argc, argv, prefix, builtin_merge_options,
 963                        builtin_merge_usage, 0);
 964        if (verbosity < 0)
 965                show_diffstat = 0;
 966
 967        if (squash) {
 968                if (!allow_fast_forward)
 969                        die("You cannot combine --squash with --no-ff.");
 970                option_commit = 0;
 971        }
 972
 973        if (!allow_fast_forward && fast_forward_only)
 974                die("You cannot combine --no-ff with --ff-only.");
 975
 976        if (!argc)
 977                usage_with_options(builtin_merge_usage,
 978                        builtin_merge_options);
 979
 980        /*
 981         * This could be traditional "merge <msg> HEAD <commit>..."  and
 982         * the way we can tell it is to see if the second token is HEAD,
 983         * but some people might have misused the interface and used a
 984         * committish that is the same as HEAD there instead.
 985         * Traditional format never would have "-m" so it is an
 986         * additional safety measure to check for it.
 987         */
 988
 989        if (!have_message && is_old_style_invocation(argc, argv)) {
 990                strbuf_addstr(&merge_msg, argv[0]);
 991                head_arg = argv[1];
 992                argv += 2;
 993                argc -= 2;
 994        } else if (head_invalid) {
 995                struct object *remote_head;
 996                /*
 997                 * If the merged head is a valid one there is no reason
 998                 * to forbid "git merge" into a branch yet to be born.
 999                 * We do the same for "git pull".
1000                 */
1001                if (argc != 1)
1002                        die("Can merge only exactly one commit into "
1003                                "empty head");
1004                if (squash)
1005                        die("Squash commit into empty head not supported yet");
1006                if (!allow_fast_forward)
1007                        die("Non-fast-forward commit does not make sense into "
1008                            "an empty head");
1009                remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
1010                if (!remote_head)
1011                        die("%s - not something we can merge", argv[0]);
1012                update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
1013                                DIE_ON_ERR);
1014                read_empty(remote_head->sha1, 0);
1015                return 0;
1016        } else {
1017                struct strbuf merge_names = STRBUF_INIT;
1018
1019                /* We are invoked directly as the first-class UI. */
1020                head_arg = "HEAD";
1021
1022                /*
1023                 * All the rest are the commits being merged;
1024                 * prepare the standard merge summary message to
1025                 * be appended to the given message.  If remote
1026                 * is invalid we will die later in the common
1027                 * codepath so we discard the error in this
1028                 * loop.
1029                 */
1030                for (i = 0; i < argc; i++)
1031                        merge_name(argv[i], &merge_names);
1032
1033                if (have_message && option_log)
1034                        fmt_merge_msg_shortlog(&merge_names, &merge_msg);
1035                else if (!have_message)
1036                        fmt_merge_msg(option_log, &merge_names, &merge_msg);
1037
1038
1039                if (!(have_message && !option_log) && merge_msg.len)
1040                        strbuf_setlen(&merge_msg, merge_msg.len-1);
1041        }
1042
1043        if (head_invalid || !argc)
1044                usage_with_options(builtin_merge_usage,
1045                        builtin_merge_options);
1046
1047        strbuf_addstr(&buf, "merge");
1048        for (i = 0; i < argc; i++)
1049                strbuf_addf(&buf, " %s", argv[i]);
1050        setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1051        strbuf_reset(&buf);
1052
1053        for (i = 0; i < argc; i++) {
1054                struct object *o;
1055                struct commit *commit;
1056
1057                o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1058                if (!o)
1059                        die("%s - not something we can merge", argv[i]);
1060                commit = lookup_commit(o->sha1);
1061                commit->util = (void *)argv[i];
1062                remotes = &commit_list_insert(commit, remotes)->next;
1063
1064                strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1065                setenv(buf.buf, argv[i], 1);
1066                strbuf_reset(&buf);
1067        }
1068
1069        if (!use_strategies) {
1070                if (!remoteheads->next)
1071                        add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1072                else
1073                        add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1074        }
1075
1076        for (i = 0; i < use_strategies_nr; i++) {
1077                if (use_strategies[i]->attr & NO_FAST_FORWARD)
1078                        allow_fast_forward = 0;
1079                if (use_strategies[i]->attr & NO_TRIVIAL)
1080                        allow_trivial = 0;
1081        }
1082
1083        if (!remoteheads->next)
1084                common = get_merge_bases(lookup_commit(head),
1085                                remoteheads->item, 1);
1086        else {
1087                struct commit_list *list = remoteheads;
1088                commit_list_insert(lookup_commit(head), &list);
1089                common = get_octopus_merge_bases(list);
1090                free(list);
1091        }
1092
1093        update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1094                DIE_ON_ERR);
1095
1096        if (!common)
1097                ; /* No common ancestors found. We need a real merge. */
1098        else if (!remoteheads->next && !common->next &&
1099                        common->item == remoteheads->item) {
1100                /*
1101                 * If head can reach all the merge then we are up to date.
1102                 * but first the most common case of merging one remote.
1103                 */
1104                finish_up_to_date("Already up-to-date.");
1105                return 0;
1106        } else if (allow_fast_forward && !remoteheads->next &&
1107                        !common->next &&
1108                        !hashcmp(common->item->object.sha1, head)) {
1109                /* Again the most common case of merging one remote. */
1110                struct strbuf msg = STRBUF_INIT;
1111                struct object *o;
1112                char hex[41];
1113
1114                strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1115
1116                if (verbosity >= 0)
1117                        printf("Updating %s..%s\n",
1118                                hex,
1119                                find_unique_abbrev(remoteheads->item->object.sha1,
1120                                DEFAULT_ABBREV));
1121                strbuf_addstr(&msg, "Fast-forward");
1122                if (have_message)
1123                        strbuf_addstr(&msg,
1124                                " (no commit created; -m option ignored)");
1125                o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1126                        0, NULL, OBJ_COMMIT);
1127                if (!o)
1128                        return 1;
1129
1130                if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1131                        return 1;
1132
1133                finish(o->sha1, msg.buf);
1134                drop_save();
1135                return 0;
1136        } else if (!remoteheads->next && common->next)
1137                ;
1138                /*
1139                 * We are not doing octopus and not fast-forward.  Need
1140                 * a real merge.
1141                 */
1142        else if (!remoteheads->next && !common->next && option_commit) {
1143                /*
1144                 * We are not doing octopus, not fast-forward, and have
1145                 * only one common.
1146                 */
1147                refresh_cache(REFRESH_QUIET);
1148                if (allow_trivial && !fast_forward_only) {
1149                        /* See if it is really trivial. */
1150                        git_committer_info(IDENT_ERROR_ON_NO_NAME);
1151                        printf("Trying really trivial in-index merge...\n");
1152                        if (!read_tree_trivial(common->item->object.sha1,
1153                                        head, remoteheads->item->object.sha1))
1154                                return merge_trivial();
1155                        printf("Nope.\n");
1156                }
1157        } else {
1158                /*
1159                 * An octopus.  If we can reach all the remote we are up
1160                 * to date.
1161                 */
1162                int up_to_date = 1;
1163                struct commit_list *j;
1164
1165                for (j = remoteheads; j; j = j->next) {
1166                        struct commit_list *common_one;
1167
1168                        /*
1169                         * Here we *have* to calculate the individual
1170                         * merge_bases again, otherwise "git merge HEAD^
1171                         * HEAD^^" would be missed.
1172                         */
1173                        common_one = get_merge_bases(lookup_commit(head),
1174                                j->item, 1);
1175                        if (hashcmp(common_one->item->object.sha1,
1176                                j->item->object.sha1)) {
1177                                up_to_date = 0;
1178                                break;
1179                        }
1180                }
1181                if (up_to_date) {
1182                        finish_up_to_date("Already up-to-date. Yeeah!");
1183                        return 0;
1184                }
1185        }
1186
1187        if (fast_forward_only)
1188                die("Not possible to fast-forward, aborting.");
1189
1190        /* We are going to make a new commit. */
1191        git_committer_info(IDENT_ERROR_ON_NO_NAME);
1192
1193        /*
1194         * At this point, we need a real merge.  No matter what strategy
1195         * we use, it would operate on the index, possibly affecting the
1196         * working tree, and when resolved cleanly, have the desired
1197         * tree in the index -- this means that the index must be in
1198         * sync with the head commit.  The strategies are responsible
1199         * to ensure this.
1200         */
1201        if (use_strategies_nr != 1) {
1202                /*
1203                 * Stash away the local changes so that we can try more
1204                 * than one.
1205                 */
1206                save_state();
1207        } else {
1208                memcpy(stash, null_sha1, 20);
1209        }
1210
1211        for (i = 0; i < use_strategies_nr; i++) {
1212                int ret;
1213                if (i) {
1214                        printf("Rewinding the tree to pristine...\n");
1215                        restore_state();
1216                }
1217                if (use_strategies_nr != 1)
1218                        printf("Trying merge strategy %s...\n",
1219                                use_strategies[i]->name);
1220                /*
1221                 * Remember which strategy left the state in the working
1222                 * tree.
1223                 */
1224                wt_strategy = use_strategies[i]->name;
1225
1226                ret = try_merge_strategy(use_strategies[i]->name,
1227                        common, head_arg);
1228                if (!option_commit && !ret) {
1229                        merge_was_ok = 1;
1230                        /*
1231                         * This is necessary here just to avoid writing
1232                         * the tree, but later we will *not* exit with
1233                         * status code 1 because merge_was_ok is set.
1234                         */
1235                        ret = 1;
1236                }
1237
1238                if (ret) {
1239                        /*
1240                         * The backend exits with 1 when conflicts are
1241                         * left to be resolved, with 2 when it does not
1242                         * handle the given merge at all.
1243                         */
1244                        if (ret == 1) {
1245                                int cnt = evaluate_result();
1246
1247                                if (best_cnt <= 0 || cnt <= best_cnt) {
1248                                        best_strategy = use_strategies[i]->name;
1249                                        best_cnt = cnt;
1250                                }
1251                        }
1252                        if (merge_was_ok)
1253                                break;
1254                        else
1255                                continue;
1256                }
1257
1258                /* Automerge succeeded. */
1259                write_tree_trivial(result_tree);
1260                automerge_was_ok = 1;
1261                break;
1262        }
1263
1264        /*
1265         * If we have a resulting tree, that means the strategy module
1266         * auto resolved the merge cleanly.
1267         */
1268        if (automerge_was_ok)
1269                return finish_automerge(common, result_tree, wt_strategy);
1270
1271        /*
1272         * Pick the result from the best strategy and have the user fix
1273         * it up.
1274         */
1275        if (!best_strategy) {
1276                restore_state();
1277                if (use_strategies_nr > 1)
1278                        fprintf(stderr,
1279                                "No merge strategy handled the merge.\n");
1280                else
1281                        fprintf(stderr, "Merge with strategy %s failed.\n",
1282                                use_strategies[0]->name);
1283                return 2;
1284        } else if (best_strategy == wt_strategy)
1285                ; /* We already have its result in the working tree. */
1286        else {
1287                printf("Rewinding the tree to pristine...\n");
1288                restore_state();
1289                printf("Using the %s to prepare resolving by hand.\n",
1290                        best_strategy);
1291                try_merge_strategy(best_strategy, common, head_arg);
1292        }
1293
1294        if (squash)
1295                finish(NULL, NULL);
1296        else {
1297                int fd;
1298                struct commit_list *j;
1299
1300                for (j = remoteheads; j; j = j->next)
1301                        strbuf_addf(&buf, "%s\n",
1302                                sha1_to_hex(j->item->object.sha1));
1303                fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1304                if (fd < 0)
1305                        die_errno("Could not open '%s' for writing",
1306                                  git_path("MERGE_HEAD"));
1307                if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1308                        die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1309                close(fd);
1310                strbuf_addch(&merge_msg, '\n');
1311                fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1312                if (fd < 0)
1313                        die_errno("Could not open '%s' for writing",
1314                                  git_path("MERGE_MSG"));
1315                if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1316                        merge_msg.len)
1317                        die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1318                close(fd);
1319                fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1320                if (fd < 0)
1321                        die_errno("Could not open '%s' for writing",
1322                                  git_path("MERGE_MODE"));
1323                strbuf_reset(&buf);
1324                if (!allow_fast_forward)
1325                        strbuf_addf(&buf, "no-ff");
1326                if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1327                        die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1328                close(fd);
1329        }
1330
1331        if (merge_was_ok) {
1332                fprintf(stderr, "Automatic merge went well; "
1333                        "stopped before committing as requested\n");
1334                return 0;
1335        } else
1336                return suggest_conflicts(option_renormalize);
1337}