924b156950982db56ab6ddf1093aff30375e5ee4
   1#include "cache.h"
   2#include "submodule.h"
   3#include "dir.h"
   4#include "diff.h"
   5#include "commit.h"
   6#include "revision.h"
   7#include "run-command.h"
   8#include "diffcore.h"
   9#include "refs.h"
  10#include "string-list.h"
  11
  12struct string_list config_name_for_path;
  13struct string_list config_fetch_recurse_submodules_for_name;
  14struct string_list config_ignore_for_name;
  15static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
  16struct string_list changed_submodule_paths;
  17
  18static int add_submodule_odb(const char *path)
  19{
  20        struct strbuf objects_directory = STRBUF_INIT;
  21        struct alternate_object_database *alt_odb;
  22        int ret = 0;
  23        const char *git_dir;
  24
  25        strbuf_addf(&objects_directory, "%s/.git", path);
  26        git_dir = read_gitfile_gently(objects_directory.buf);
  27        if (git_dir) {
  28                strbuf_reset(&objects_directory);
  29                strbuf_addstr(&objects_directory, git_dir);
  30        }
  31        strbuf_addstr(&objects_directory, "/objects/");
  32        if (!is_directory(objects_directory.buf)) {
  33                ret = -1;
  34                goto done;
  35        }
  36        /* avoid adding it twice */
  37        for (alt_odb = alt_odb_list; alt_odb; alt_odb = alt_odb->next)
  38                if (alt_odb->name - alt_odb->base == objects_directory.len &&
  39                                !strncmp(alt_odb->base, objects_directory.buf,
  40                                        objects_directory.len))
  41                        goto done;
  42
  43        alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
  44        alt_odb->next = alt_odb_list;
  45        strcpy(alt_odb->base, objects_directory.buf);
  46        alt_odb->name = alt_odb->base + objects_directory.len;
  47        alt_odb->name[2] = '/';
  48        alt_odb->name[40] = '\0';
  49        alt_odb->name[41] = '\0';
  50        alt_odb_list = alt_odb;
  51        prepare_alt_odb();
  52done:
  53        strbuf_release(&objects_directory);
  54        return ret;
  55}
  56
  57void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
  58                                             const char *path)
  59{
  60        struct string_list_item *path_option, *ignore_option;
  61        path_option = unsorted_string_list_lookup(&config_name_for_path, path);
  62        if (path_option) {
  63                ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
  64                if (ignore_option)
  65                        handle_ignore_submodules_arg(diffopt, ignore_option->util);
  66        }
  67}
  68
  69int submodule_config(const char *var, const char *value, void *cb)
  70{
  71        if (!prefixcmp(var, "submodule."))
  72                return parse_submodule_config_option(var, value);
  73        else if (!strcmp(var, "fetch.recursesubmodules")) {
  74                config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
  75                return 0;
  76        }
  77        return 0;
  78}
  79
  80void gitmodules_config(void)
  81{
  82        const char *work_tree = get_git_work_tree();
  83        if (work_tree) {
  84                struct strbuf gitmodules_path = STRBUF_INIT;
  85                strbuf_addstr(&gitmodules_path, work_tree);
  86                strbuf_addstr(&gitmodules_path, "/.gitmodules");
  87                git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
  88                strbuf_release(&gitmodules_path);
  89        }
  90}
  91
  92int parse_submodule_config_option(const char *var, const char *value)
  93{
  94        int len;
  95        struct string_list_item *config;
  96        struct strbuf submodname = STRBUF_INIT;
  97
  98        var += 10;              /* Skip "submodule." */
  99
 100        len = strlen(var);
 101        if ((len > 5) && !strcmp(var + len - 5, ".path")) {
 102                strbuf_add(&submodname, var, len - 5);
 103                config = unsorted_string_list_lookup(&config_name_for_path, value);
 104                if (config)
 105                        free(config->util);
 106                else
 107                        config = string_list_append(&config_name_for_path, xstrdup(value));
 108                config->util = strbuf_detach(&submodname, NULL);
 109                strbuf_release(&submodname);
 110        } else if ((len > 23) && !strcmp(var + len - 23, ".fetchrecursesubmodules")) {
 111                strbuf_add(&submodname, var, len - 23);
 112                config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, submodname.buf);
 113                if (!config)
 114                        config = string_list_append(&config_fetch_recurse_submodules_for_name,
 115                                                    strbuf_detach(&submodname, NULL));
 116                config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
 117                strbuf_release(&submodname);
 118        } else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
 119                if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
 120                    strcmp(value, "all") && strcmp(value, "none")) {
 121                        warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
 122                        return 0;
 123                }
 124
 125                strbuf_add(&submodname, var, len - 7);
 126                config = unsorted_string_list_lookup(&config_ignore_for_name, submodname.buf);
 127                if (config)
 128                        free(config->util);
 129                else
 130                        config = string_list_append(&config_ignore_for_name,
 131                                                    strbuf_detach(&submodname, NULL));
 132                strbuf_release(&submodname);
 133                config->util = xstrdup(value);
 134                return 0;
 135        }
 136        return 0;
 137}
 138
 139void handle_ignore_submodules_arg(struct diff_options *diffopt,
 140                                  const char *arg)
 141{
 142        DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
 143        DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 144        DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
 145
 146        if (!strcmp(arg, "all"))
 147                DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 148        else if (!strcmp(arg, "untracked"))
 149                DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 150        else if (!strcmp(arg, "dirty"))
 151                DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
 152        else if (strcmp(arg, "none"))
 153                die("bad --ignore-submodules argument: %s", arg);
 154}
 155
 156int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
 157{
 158        switch (git_config_maybe_bool(opt, arg)) {
 159        case 1:
 160                return RECURSE_SUBMODULES_ON;
 161        case 0:
 162                return RECURSE_SUBMODULES_OFF;
 163        default:
 164                if (!strcmp(arg, "on-demand"))
 165                        return RECURSE_SUBMODULES_ON_DEMAND;
 166                die("bad %s argument: %s", opt, arg);
 167        }
 168}
 169
 170void show_submodule_summary(FILE *f, const char *path,
 171                unsigned char one[20], unsigned char two[20],
 172                unsigned dirty_submodule,
 173                const char *del, const char *add, const char *reset)
 174{
 175        struct rev_info rev;
 176        struct commit *commit, *left = left, *right = right;
 177        struct commit_list *merge_bases, *list;
 178        const char *message = NULL;
 179        struct strbuf sb = STRBUF_INIT;
 180        static const char *format = "  %m %s";
 181        int fast_forward = 0, fast_backward = 0;
 182
 183        if (is_null_sha1(two))
 184                message = "(submodule deleted)";
 185        else if (add_submodule_odb(path))
 186                message = "(not checked out)";
 187        else if (is_null_sha1(one))
 188                message = "(new submodule)";
 189        else if (!(left = lookup_commit_reference(one)) ||
 190                 !(right = lookup_commit_reference(two)))
 191                message = "(commits not present)";
 192
 193        if (!message) {
 194                init_revisions(&rev, NULL);
 195                setup_revisions(0, NULL, &rev, NULL);
 196                rev.left_right = 1;
 197                rev.first_parent_only = 1;
 198                left->object.flags |= SYMMETRIC_LEFT;
 199                add_pending_object(&rev, &left->object, path);
 200                add_pending_object(&rev, &right->object, path);
 201                merge_bases = get_merge_bases(left, right, 1);
 202                if (merge_bases) {
 203                        if (merge_bases->item == left)
 204                                fast_forward = 1;
 205                        else if (merge_bases->item == right)
 206                                fast_backward = 1;
 207                }
 208                for (list = merge_bases; list; list = list->next) {
 209                        list->item->object.flags |= UNINTERESTING;
 210                        add_pending_object(&rev, &list->item->object,
 211                                sha1_to_hex(list->item->object.sha1));
 212                }
 213                if (prepare_revision_walk(&rev))
 214                        message = "(revision walker failed)";
 215        }
 216
 217        if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
 218                fprintf(f, "Submodule %s contains untracked content\n", path);
 219        if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 220                fprintf(f, "Submodule %s contains modified content\n", path);
 221
 222        if (!hashcmp(one, two)) {
 223                strbuf_release(&sb);
 224                return;
 225        }
 226
 227        strbuf_addf(&sb, "Submodule %s %s..", path,
 228                        find_unique_abbrev(one, DEFAULT_ABBREV));
 229        if (!fast_backward && !fast_forward)
 230                strbuf_addch(&sb, '.');
 231        strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
 232        if (message)
 233                strbuf_addf(&sb, " %s\n", message);
 234        else
 235                strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
 236        fwrite(sb.buf, sb.len, 1, f);
 237
 238        if (!message) {
 239                while ((commit = get_revision(&rev))) {
 240                        struct pretty_print_context ctx = {0};
 241                        ctx.date_mode = rev.date_mode;
 242                        strbuf_setlen(&sb, 0);
 243                        if (commit->object.flags & SYMMETRIC_LEFT) {
 244                                if (del)
 245                                        strbuf_addstr(&sb, del);
 246                        }
 247                        else if (add)
 248                                strbuf_addstr(&sb, add);
 249                        format_commit_message(commit, format, &sb, &ctx);
 250                        if (reset)
 251                                strbuf_addstr(&sb, reset);
 252                        strbuf_addch(&sb, '\n');
 253                        fprintf(f, "%s", sb.buf);
 254                }
 255                clear_commit_marks(left, ~0);
 256                clear_commit_marks(right, ~0);
 257        }
 258        strbuf_release(&sb);
 259}
 260
 261void set_config_fetch_recurse_submodules(int value)
 262{
 263        config_fetch_recurse_submodules = value;
 264}
 265
 266static void submodule_collect_changed_cb(struct diff_queue_struct *q,
 267                                         struct diff_options *options,
 268                                         void *data)
 269{
 270        int i;
 271        for (i = 0; i < q->nr; i++) {
 272                struct diff_filepair *p = q->queue[i];
 273                if (!S_ISGITLINK(p->two->mode))
 274                        continue;
 275
 276                if (S_ISGITLINK(p->one->mode)) {
 277                        /* NEEDSWORK: We should honor the name configured in
 278                         * the .gitmodules file of the commit we are examining
 279                         * here to be able to correctly follow submodules
 280                         * being moved around. */
 281                        struct string_list_item *path;
 282                        path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
 283                        if (!path)
 284                                string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
 285                } else {
 286                        /* Submodule is new or was moved here */
 287                        /* NEEDSWORK: When the .git directories of submodules
 288                         * live inside the superprojects .git directory some
 289                         * day we should fetch new submodules directly into
 290                         * that location too when config or options request
 291                         * that so they can be checked out from there. */
 292                        continue;
 293                }
 294        }
 295}
 296
 297void check_for_new_submodule_commits(unsigned char new_sha1[20])
 298{
 299        struct rev_info rev;
 300        struct commit *commit;
 301        const char *argv[] = {NULL, NULL, "--not", "--all", NULL};
 302        int argc = ARRAY_SIZE(argv) - 1;
 303
 304        init_revisions(&rev, NULL);
 305        argv[1] = xstrdup(sha1_to_hex(new_sha1));
 306        setup_revisions(argc, argv, &rev, NULL);
 307        if (prepare_revision_walk(&rev))
 308                die("revision walk setup failed");
 309
 310        /*
 311         * Collect all submodules (whether checked out or not) for which new
 312         * commits have been recorded upstream in "changed_submodule_paths".
 313         */
 314        while ((commit = get_revision(&rev))) {
 315                struct commit_list *parent = commit->parents;
 316                while (parent) {
 317                        struct diff_options diff_opts;
 318                        diff_setup(&diff_opts);
 319                        diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
 320                        diff_opts.format_callback = submodule_collect_changed_cb;
 321                        if (diff_setup_done(&diff_opts) < 0)
 322                                die("diff_setup_done failed");
 323                        diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
 324                        diffcore_std(&diff_opts);
 325                        diff_flush(&diff_opts);
 326                        parent = parent->next;
 327                }
 328        }
 329        free((char *)argv[1]);
 330}
 331
 332int fetch_populated_submodules(int num_options, const char **options,
 333                               const char *prefix, int command_line_option,
 334                               int quiet)
 335{
 336        int i, result = 0, argc = 0, default_argc;
 337        struct child_process cp;
 338        const char **argv;
 339        struct string_list_item *name_for_path;
 340        const char *work_tree = get_git_work_tree();
 341        if (!work_tree)
 342                goto out;
 343
 344        if (!the_index.initialized)
 345                if (read_cache() < 0)
 346                        die("index file corrupt");
 347
 348        /* 6: "fetch" (options) --recurse-submodules-default default "--submodule-prefix" prefix NULL */
 349        argv = xcalloc(num_options + 6, sizeof(const char *));
 350        argv[argc++] = "fetch";
 351        for (i = 0; i < num_options; i++)
 352                argv[argc++] = options[i];
 353        argv[argc++] = "--recurse-submodules-default";
 354        default_argc = argc++;
 355        argv[argc++] = "--submodule-prefix";
 356
 357        memset(&cp, 0, sizeof(cp));
 358        cp.argv = argv;
 359        cp.env = local_repo_env;
 360        cp.git_cmd = 1;
 361        cp.no_stdin = 1;
 362
 363        for (i = 0; i < active_nr; i++) {
 364                struct strbuf submodule_path = STRBUF_INIT;
 365                struct strbuf submodule_git_dir = STRBUF_INIT;
 366                struct strbuf submodule_prefix = STRBUF_INIT;
 367                struct cache_entry *ce = active_cache[i];
 368                const char *git_dir, *name, *default_argv;
 369
 370                if (!S_ISGITLINK(ce->ce_mode))
 371                        continue;
 372
 373                name = ce->name;
 374                name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
 375                if (name_for_path)
 376                        name = name_for_path->util;
 377
 378                default_argv = "yes";
 379                if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
 380                        struct string_list_item *fetch_recurse_submodules_option;
 381                        fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
 382                        if (fetch_recurse_submodules_option) {
 383                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
 384                                        continue;
 385                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
 386                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 387                                                continue;
 388                                        default_argv = "on-demand";
 389                                }
 390                        } else {
 391                                if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF)
 392                                        continue;
 393                                if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
 394                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 395                                                continue;
 396                                        default_argv = "on-demand";
 397                                }
 398                        }
 399                } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
 400                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 401                                continue;
 402                        default_argv = "on-demand";
 403                }
 404
 405                strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
 406                strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 407                strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
 408                git_dir = read_gitfile_gently(submodule_git_dir.buf);
 409                if (!git_dir)
 410                        git_dir = submodule_git_dir.buf;
 411                if (is_directory(git_dir)) {
 412                        if (!quiet)
 413                                printf("Fetching submodule %s%s\n", prefix, ce->name);
 414                        cp.dir = submodule_path.buf;
 415                        argv[default_argc] = default_argv;
 416                        argv[argc] = submodule_prefix.buf;
 417                        if (run_command(&cp))
 418                                result = 1;
 419                }
 420                strbuf_release(&submodule_path);
 421                strbuf_release(&submodule_git_dir);
 422                strbuf_release(&submodule_prefix);
 423        }
 424        free(argv);
 425out:
 426        string_list_clear(&changed_submodule_paths, 1);
 427        return result;
 428}
 429
 430unsigned is_submodule_modified(const char *path, int ignore_untracked)
 431{
 432        ssize_t len;
 433        struct child_process cp;
 434        const char *argv[] = {
 435                "status",
 436                "--porcelain",
 437                NULL,
 438                NULL,
 439        };
 440        struct strbuf buf = STRBUF_INIT;
 441        unsigned dirty_submodule = 0;
 442        const char *line, *next_line;
 443        const char *git_dir;
 444
 445        strbuf_addf(&buf, "%s/.git", path);
 446        git_dir = read_gitfile_gently(buf.buf);
 447        if (!git_dir)
 448                git_dir = buf.buf;
 449        if (!is_directory(git_dir)) {
 450                strbuf_release(&buf);
 451                /* The submodule is not checked out, so it is not modified */
 452                return 0;
 453
 454        }
 455        strbuf_reset(&buf);
 456
 457        if (ignore_untracked)
 458                argv[2] = "-uno";
 459
 460        memset(&cp, 0, sizeof(cp));
 461        cp.argv = argv;
 462        cp.env = local_repo_env;
 463        cp.git_cmd = 1;
 464        cp.no_stdin = 1;
 465        cp.out = -1;
 466        cp.dir = path;
 467        if (start_command(&cp))
 468                die("Could not run git status --porcelain");
 469
 470        len = strbuf_read(&buf, cp.out, 1024);
 471        line = buf.buf;
 472        while (len > 2) {
 473                if ((line[0] == '?') && (line[1] == '?')) {
 474                        dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
 475                        if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 476                                break;
 477                } else {
 478                        dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
 479                        if (ignore_untracked ||
 480                            (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
 481                                break;
 482                }
 483                next_line = strchr(line, '\n');
 484                if (!next_line)
 485                        break;
 486                next_line++;
 487                len -= (next_line - line);
 488                line = next_line;
 489        }
 490        close(cp.out);
 491
 492        if (finish_command(&cp))
 493                die("git status --porcelain failed");
 494
 495        strbuf_release(&buf);
 496        return dirty_submodule;
 497}
 498
 499static int find_first_merges(struct object_array *result, const char *path,
 500                struct commit *a, struct commit *b)
 501{
 502        int i, j;
 503        struct object_array merges;
 504        struct commit *commit;
 505        int contains_another;
 506
 507        char merged_revision[42];
 508        const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
 509                                   "--all", merged_revision, NULL };
 510        struct rev_info revs;
 511        struct setup_revision_opt rev_opts;
 512
 513        memset(&merges, 0, sizeof(merges));
 514        memset(result, 0, sizeof(struct object_array));
 515        memset(&rev_opts, 0, sizeof(rev_opts));
 516
 517        /* get all revisions that merge commit a */
 518        snprintf(merged_revision, sizeof(merged_revision), "^%s",
 519                        sha1_to_hex(a->object.sha1));
 520        init_revisions(&revs, NULL);
 521        rev_opts.submodule = path;
 522        setup_revisions(sizeof(rev_args)/sizeof(char *)-1, rev_args, &revs, &rev_opts);
 523
 524        /* save all revisions from the above list that contain b */
 525        if (prepare_revision_walk(&revs))
 526                die("revision walk setup failed");
 527        while ((commit = get_revision(&revs)) != NULL) {
 528                struct object *o = &(commit->object);
 529                if (in_merge_bases(b, &commit, 1))
 530                        add_object_array(o, NULL, &merges);
 531        }
 532
 533        /* Now we've got all merges that contain a and b. Prune all
 534         * merges that contain another found merge and save them in
 535         * result.
 536         */
 537        for (i = 0; i < merges.nr; i++) {
 538                struct commit *m1 = (struct commit *) merges.objects[i].item;
 539
 540                contains_another = 0;
 541                for (j = 0; j < merges.nr; j++) {
 542                        struct commit *m2 = (struct commit *) merges.objects[j].item;
 543                        if (i != j && in_merge_bases(m2, &m1, 1)) {
 544                                contains_another = 1;
 545                                break;
 546                        }
 547                }
 548
 549                if (!contains_another)
 550                        add_object_array(merges.objects[i].item,
 551                                         merges.objects[i].name, result);
 552        }
 553
 554        free(merges.objects);
 555        return result->nr;
 556}
 557
 558static void print_commit(struct commit *commit)
 559{
 560        struct strbuf sb = STRBUF_INIT;
 561        struct pretty_print_context ctx = {0};
 562        ctx.date_mode = DATE_NORMAL;
 563        format_commit_message(commit, " %h: %m %s", &sb, &ctx);
 564        fprintf(stderr, "%s\n", sb.buf);
 565        strbuf_release(&sb);
 566}
 567
 568#define MERGE_WARNING(path, msg) \
 569        warning("Failed to merge submodule %s (%s)", path, msg);
 570
 571int merge_submodule(unsigned char result[20], const char *path,
 572                    const unsigned char base[20], const unsigned char a[20],
 573                    const unsigned char b[20])
 574{
 575        struct commit *commit_base, *commit_a, *commit_b;
 576        int parent_count;
 577        struct object_array merges;
 578
 579        int i;
 580
 581        /* store a in result in case we fail */
 582        hashcpy(result, a);
 583
 584        /* we can not handle deletion conflicts */
 585        if (is_null_sha1(base))
 586                return 0;
 587        if (is_null_sha1(a))
 588                return 0;
 589        if (is_null_sha1(b))
 590                return 0;
 591
 592        if (add_submodule_odb(path)) {
 593                MERGE_WARNING(path, "not checked out");
 594                return 0;
 595        }
 596
 597        if (!(commit_base = lookup_commit_reference(base)) ||
 598            !(commit_a = lookup_commit_reference(a)) ||
 599            !(commit_b = lookup_commit_reference(b))) {
 600                MERGE_WARNING(path, "commits not present");
 601                return 0;
 602        }
 603
 604        /* check whether both changes are forward */
 605        if (!in_merge_bases(commit_base, &commit_a, 1) ||
 606            !in_merge_bases(commit_base, &commit_b, 1)) {
 607                MERGE_WARNING(path, "commits don't follow merge-base");
 608                return 0;
 609        }
 610
 611        /* Case #1: a is contained in b or vice versa */
 612        if (in_merge_bases(commit_a, &commit_b, 1)) {
 613                hashcpy(result, b);
 614                return 1;
 615        }
 616        if (in_merge_bases(commit_b, &commit_a, 1)) {
 617                hashcpy(result, a);
 618                return 1;
 619        }
 620
 621        /*
 622         * Case #2: There are one or more merges that contain a and b in
 623         * the submodule. If there is only one, then present it as a
 624         * suggestion to the user, but leave it marked unmerged so the
 625         * user needs to confirm the resolution.
 626         */
 627
 628        /* find commit which merges them */
 629        parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 630        switch (parent_count) {
 631        case 0:
 632                MERGE_WARNING(path, "merge following commits not found");
 633                break;
 634
 635        case 1:
 636                MERGE_WARNING(path, "not fast-forward");
 637                fprintf(stderr, "Found a possible merge resolution "
 638                                "for the submodule:\n");
 639                print_commit((struct commit *) merges.objects[0].item);
 640                fprintf(stderr,
 641                        "If this is correct simply add it to the index "
 642                        "for example\n"
 643                        "by using:\n\n"
 644                        "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
 645                        "which will accept this suggestion.\n",
 646                        sha1_to_hex(merges.objects[0].item->sha1), path);
 647                break;
 648
 649        default:
 650                MERGE_WARNING(path, "multiple merges found");
 651                for (i = 0; i < merges.nr; i++)
 652                        print_commit((struct commit *) merges.objects[i].item);
 653        }
 654
 655        free(merges.objects);
 656        return 0;
 657}