submodule.con commit Merge branch 'an/shallow-doc' into maint (3e8cd96)
   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
  12static struct string_list config_name_for_path;
  13static struct string_list config_fetch_recurse_submodules_for_name;
  14static struct string_list config_ignore_for_name;
  15static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
  16static struct string_list changed_submodule_paths;
  17/*
  18 * The following flag is set if the .gitmodules file is unmerged. We then
  19 * disable recursion for all submodules where .git/config doesn't have a
  20 * matching config entry because we can't guess what might be configured in
  21 * .gitmodules unless the user resolves the conflict. When a command line
  22 * option is given (which always overrides configuration) this flag will be
  23 * ignored.
  24 */
  25static int gitmodules_is_unmerged;
  26
  27static int add_submodule_odb(const char *path)
  28{
  29        struct strbuf objects_directory = STRBUF_INIT;
  30        struct alternate_object_database *alt_odb;
  31        int ret = 0;
  32        const char *git_dir;
  33
  34        strbuf_addf(&objects_directory, "%s/.git", path);
  35        git_dir = read_gitfile_gently(objects_directory.buf);
  36        if (git_dir) {
  37                strbuf_reset(&objects_directory);
  38                strbuf_addstr(&objects_directory, git_dir);
  39        }
  40        strbuf_addstr(&objects_directory, "/objects/");
  41        if (!is_directory(objects_directory.buf)) {
  42                ret = -1;
  43                goto done;
  44        }
  45        /* avoid adding it twice */
  46        for (alt_odb = alt_odb_list; alt_odb; alt_odb = alt_odb->next)
  47                if (alt_odb->name - alt_odb->base == objects_directory.len &&
  48                                !strncmp(alt_odb->base, objects_directory.buf,
  49                                        objects_directory.len))
  50                        goto done;
  51
  52        alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
  53        alt_odb->next = alt_odb_list;
  54        strcpy(alt_odb->base, objects_directory.buf);
  55        alt_odb->name = alt_odb->base + objects_directory.len;
  56        alt_odb->name[2] = '/';
  57        alt_odb->name[40] = '\0';
  58        alt_odb->name[41] = '\0';
  59        alt_odb_list = alt_odb;
  60        prepare_alt_odb();
  61done:
  62        strbuf_release(&objects_directory);
  63        return ret;
  64}
  65
  66void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
  67                                             const char *path)
  68{
  69        struct string_list_item *path_option, *ignore_option;
  70        path_option = unsorted_string_list_lookup(&config_name_for_path, path);
  71        if (path_option) {
  72                ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
  73                if (ignore_option)
  74                        handle_ignore_submodules_arg(diffopt, ignore_option->util);
  75                else if (gitmodules_is_unmerged)
  76                        DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
  77        }
  78}
  79
  80int submodule_config(const char *var, const char *value, void *cb)
  81{
  82        if (!prefixcmp(var, "submodule."))
  83                return parse_submodule_config_option(var, value);
  84        else if (!strcmp(var, "fetch.recursesubmodules")) {
  85                config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
  86                return 0;
  87        }
  88        return 0;
  89}
  90
  91void gitmodules_config(void)
  92{
  93        const char *work_tree = get_git_work_tree();
  94        if (work_tree) {
  95                struct strbuf gitmodules_path = STRBUF_INIT;
  96                int pos;
  97                strbuf_addstr(&gitmodules_path, work_tree);
  98                strbuf_addstr(&gitmodules_path, "/.gitmodules");
  99                if (read_cache() < 0)
 100                        die("index file corrupt");
 101                pos = cache_name_pos(".gitmodules", 11);
 102                if (pos < 0) { /* .gitmodules not found or isn't merged */
 103                        pos = -1 - pos;
 104                        if (active_nr > pos) {  /* there is a .gitmodules */
 105                                const struct cache_entry *ce = active_cache[pos];
 106                                if (ce_namelen(ce) == 11 &&
 107                                    !memcmp(ce->name, ".gitmodules", 11))
 108                                        gitmodules_is_unmerged = 1;
 109                        }
 110                }
 111
 112                if (!gitmodules_is_unmerged)
 113                        git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
 114                strbuf_release(&gitmodules_path);
 115        }
 116}
 117
 118int parse_submodule_config_option(const char *var, const char *value)
 119{
 120        int len;
 121        struct string_list_item *config;
 122        struct strbuf submodname = STRBUF_INIT;
 123
 124        var += 10;              /* Skip "submodule." */
 125
 126        len = strlen(var);
 127        if ((len > 5) && !strcmp(var + len - 5, ".path")) {
 128                strbuf_add(&submodname, var, len - 5);
 129                config = unsorted_string_list_lookup(&config_name_for_path, value);
 130                if (config)
 131                        free(config->util);
 132                else
 133                        config = string_list_append(&config_name_for_path, xstrdup(value));
 134                config->util = strbuf_detach(&submodname, NULL);
 135                strbuf_release(&submodname);
 136        } else if ((len > 23) && !strcmp(var + len - 23, ".fetchrecursesubmodules")) {
 137                strbuf_add(&submodname, var, len - 23);
 138                config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, submodname.buf);
 139                if (!config)
 140                        config = string_list_append(&config_fetch_recurse_submodules_for_name,
 141                                                    strbuf_detach(&submodname, NULL));
 142                config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
 143                strbuf_release(&submodname);
 144        } else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
 145                if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
 146                    strcmp(value, "all") && strcmp(value, "none")) {
 147                        warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
 148                        return 0;
 149                }
 150
 151                strbuf_add(&submodname, var, len - 7);
 152                config = unsorted_string_list_lookup(&config_ignore_for_name, submodname.buf);
 153                if (config)
 154                        free(config->util);
 155                else
 156                        config = string_list_append(&config_ignore_for_name,
 157                                                    strbuf_detach(&submodname, NULL));
 158                strbuf_release(&submodname);
 159                config->util = xstrdup(value);
 160                return 0;
 161        }
 162        return 0;
 163}
 164
 165void handle_ignore_submodules_arg(struct diff_options *diffopt,
 166                                  const char *arg)
 167{
 168        DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
 169        DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 170        DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
 171
 172        if (!strcmp(arg, "all"))
 173                DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 174        else if (!strcmp(arg, "untracked"))
 175                DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 176        else if (!strcmp(arg, "dirty"))
 177                DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
 178        else if (strcmp(arg, "none"))
 179                die("bad --ignore-submodules argument: %s", arg);
 180}
 181
 182static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 183                struct commit *left, struct commit *right,
 184                int *fast_forward, int *fast_backward)
 185{
 186        struct commit_list *merge_bases, *list;
 187
 188        init_revisions(rev, NULL);
 189        setup_revisions(0, NULL, rev, NULL);
 190        rev->left_right = 1;
 191        rev->first_parent_only = 1;
 192        left->object.flags |= SYMMETRIC_LEFT;
 193        add_pending_object(rev, &left->object, path);
 194        add_pending_object(rev, &right->object, path);
 195        merge_bases = get_merge_bases(left, right, 1);
 196        if (merge_bases) {
 197                if (merge_bases->item == left)
 198                        *fast_forward = 1;
 199                else if (merge_bases->item == right)
 200                        *fast_backward = 1;
 201        }
 202        for (list = merge_bases; list; list = list->next) {
 203                list->item->object.flags |= UNINTERESTING;
 204                add_pending_object(rev, &list->item->object,
 205                        sha1_to_hex(list->item->object.sha1));
 206        }
 207        return prepare_revision_walk(rev);
 208}
 209
 210static void print_submodule_summary(struct rev_info *rev, FILE *f,
 211                const char *del, const char *add, const char *reset)
 212{
 213        static const char format[] = "  %m %s";
 214        struct strbuf sb = STRBUF_INIT;
 215        struct commit *commit;
 216
 217        while ((commit = get_revision(rev))) {
 218                struct pretty_print_context ctx = {0};
 219                ctx.date_mode = rev->date_mode;
 220                strbuf_setlen(&sb, 0);
 221                if (commit->object.flags & SYMMETRIC_LEFT) {
 222                        if (del)
 223                                strbuf_addstr(&sb, del);
 224                }
 225                else if (add)
 226                        strbuf_addstr(&sb, add);
 227                format_commit_message(commit, format, &sb, &ctx);
 228                if (reset)
 229                        strbuf_addstr(&sb, reset);
 230                strbuf_addch(&sb, '\n');
 231                fprintf(f, "%s", sb.buf);
 232        }
 233        strbuf_release(&sb);
 234}
 235
 236int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
 237{
 238        switch (git_config_maybe_bool(opt, arg)) {
 239        case 1:
 240                return RECURSE_SUBMODULES_ON;
 241        case 0:
 242                return RECURSE_SUBMODULES_OFF;
 243        default:
 244                if (!strcmp(arg, "on-demand"))
 245                        return RECURSE_SUBMODULES_ON_DEMAND;
 246                die("bad %s argument: %s", opt, arg);
 247        }
 248}
 249
 250void show_submodule_summary(FILE *f, const char *path,
 251                unsigned char one[20], unsigned char two[20],
 252                unsigned dirty_submodule,
 253                const char *del, const char *add, const char *reset)
 254{
 255        struct rev_info rev;
 256        struct commit *left = left, *right = right;
 257        const char *message = NULL;
 258        struct strbuf sb = STRBUF_INIT;
 259        int fast_forward = 0, fast_backward = 0;
 260
 261        if (is_null_sha1(two))
 262                message = "(submodule deleted)";
 263        else if (add_submodule_odb(path))
 264                message = "(not checked out)";
 265        else if (is_null_sha1(one))
 266                message = "(new submodule)";
 267        else if (!(left = lookup_commit_reference(one)) ||
 268                 !(right = lookup_commit_reference(two)))
 269                message = "(commits not present)";
 270
 271        if (!message &&
 272            prepare_submodule_summary(&rev, path, left, right,
 273                                        &fast_forward, &fast_backward))
 274                message = "(revision walker failed)";
 275
 276        if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
 277                fprintf(f, "Submodule %s contains untracked content\n", path);
 278        if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 279                fprintf(f, "Submodule %s contains modified content\n", path);
 280
 281        if (!hashcmp(one, two)) {
 282                strbuf_release(&sb);
 283                return;
 284        }
 285
 286        strbuf_addf(&sb, "Submodule %s %s..", path,
 287                        find_unique_abbrev(one, DEFAULT_ABBREV));
 288        if (!fast_backward && !fast_forward)
 289                strbuf_addch(&sb, '.');
 290        strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
 291        if (message)
 292                strbuf_addf(&sb, " %s\n", message);
 293        else
 294                strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
 295        fwrite(sb.buf, sb.len, 1, f);
 296
 297        if (!message) {
 298                print_submodule_summary(&rev, f, del, add, reset);
 299                clear_commit_marks(left, ~0);
 300                clear_commit_marks(right, ~0);
 301        }
 302
 303        strbuf_release(&sb);
 304}
 305
 306void set_config_fetch_recurse_submodules(int value)
 307{
 308        config_fetch_recurse_submodules = value;
 309}
 310
 311static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 312{
 313        int is_present = 0;
 314        if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
 315                /* Even if the submodule is checked out and the commit is
 316                 * present, make sure it is reachable from a ref. */
 317                struct child_process cp;
 318                const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
 319                struct strbuf buf = STRBUF_INIT;
 320
 321                argv[3] = sha1_to_hex(sha1);
 322                memset(&cp, 0, sizeof(cp));
 323                cp.argv = argv;
 324                cp.env = local_repo_env;
 325                cp.git_cmd = 1;
 326                cp.no_stdin = 1;
 327                cp.out = -1;
 328                cp.dir = path;
 329                if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
 330                        is_present = 1;
 331
 332                close(cp.out);
 333                strbuf_release(&buf);
 334        }
 335        return is_present;
 336}
 337
 338static void submodule_collect_changed_cb(struct diff_queue_struct *q,
 339                                         struct diff_options *options,
 340                                         void *data)
 341{
 342        int i;
 343        for (i = 0; i < q->nr; i++) {
 344                struct diff_filepair *p = q->queue[i];
 345                if (!S_ISGITLINK(p->two->mode))
 346                        continue;
 347
 348                if (S_ISGITLINK(p->one->mode)) {
 349                        /* NEEDSWORK: We should honor the name configured in
 350                         * the .gitmodules file of the commit we are examining
 351                         * here to be able to correctly follow submodules
 352                         * being moved around. */
 353                        struct string_list_item *path;
 354                        path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
 355                        if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
 356                                string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
 357                } else {
 358                        /* Submodule is new or was moved here */
 359                        /* NEEDSWORK: When the .git directories of submodules
 360                         * live inside the superprojects .git directory some
 361                         * day we should fetch new submodules directly into
 362                         * that location too when config or options request
 363                         * that so they can be checked out from there. */
 364                        continue;
 365                }
 366        }
 367}
 368
 369void check_for_new_submodule_commits(unsigned char new_sha1[20])
 370{
 371        struct rev_info rev;
 372        struct commit *commit;
 373        const char *argv[] = {NULL, NULL, "--not", "--all", NULL};
 374        int argc = ARRAY_SIZE(argv) - 1;
 375
 376        init_revisions(&rev, NULL);
 377        argv[1] = xstrdup(sha1_to_hex(new_sha1));
 378        setup_revisions(argc, argv, &rev, NULL);
 379        if (prepare_revision_walk(&rev))
 380                die("revision walk setup failed");
 381
 382        /*
 383         * Collect all submodules (whether checked out or not) for which new
 384         * commits have been recorded upstream in "changed_submodule_paths".
 385         */
 386        while ((commit = get_revision(&rev))) {
 387                struct commit_list *parent = commit->parents;
 388                while (parent) {
 389                        struct diff_options diff_opts;
 390                        diff_setup(&diff_opts);
 391                        diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
 392                        diff_opts.format_callback = submodule_collect_changed_cb;
 393                        if (diff_setup_done(&diff_opts) < 0)
 394                                die("diff_setup_done failed");
 395                        diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
 396                        diffcore_std(&diff_opts);
 397                        diff_flush(&diff_opts);
 398                        parent = parent->next;
 399                }
 400        }
 401        free((char *)argv[1]);
 402}
 403
 404int fetch_populated_submodules(int num_options, const char **options,
 405                               const char *prefix, int command_line_option,
 406                               int quiet)
 407{
 408        int i, result = 0, argc = 0, default_argc;
 409        struct child_process cp;
 410        const char **argv;
 411        struct string_list_item *name_for_path;
 412        const char *work_tree = get_git_work_tree();
 413        if (!work_tree)
 414                goto out;
 415
 416        if (!the_index.initialized)
 417                if (read_cache() < 0)
 418                        die("index file corrupt");
 419
 420        /* 6: "fetch" (options) --recurse-submodules-default default "--submodule-prefix" prefix NULL */
 421        argv = xcalloc(num_options + 6, sizeof(const char *));
 422        argv[argc++] = "fetch";
 423        for (i = 0; i < num_options; i++)
 424                argv[argc++] = options[i];
 425        argv[argc++] = "--recurse-submodules-default";
 426        default_argc = argc++;
 427        argv[argc++] = "--submodule-prefix";
 428
 429        memset(&cp, 0, sizeof(cp));
 430        cp.argv = argv;
 431        cp.env = local_repo_env;
 432        cp.git_cmd = 1;
 433        cp.no_stdin = 1;
 434
 435        for (i = 0; i < active_nr; i++) {
 436                struct strbuf submodule_path = STRBUF_INIT;
 437                struct strbuf submodule_git_dir = STRBUF_INIT;
 438                struct strbuf submodule_prefix = STRBUF_INIT;
 439                struct cache_entry *ce = active_cache[i];
 440                const char *git_dir, *name, *default_argv;
 441
 442                if (!S_ISGITLINK(ce->ce_mode))
 443                        continue;
 444
 445                name = ce->name;
 446                name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
 447                if (name_for_path)
 448                        name = name_for_path->util;
 449
 450                default_argv = "yes";
 451                if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
 452                        struct string_list_item *fetch_recurse_submodules_option;
 453                        fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
 454                        if (fetch_recurse_submodules_option) {
 455                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
 456                                        continue;
 457                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
 458                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 459                                                continue;
 460                                        default_argv = "on-demand";
 461                                }
 462                        } else {
 463                                if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
 464                                    gitmodules_is_unmerged)
 465                                        continue;
 466                                if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
 467                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 468                                                continue;
 469                                        default_argv = "on-demand";
 470                                }
 471                        }
 472                } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
 473                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 474                                continue;
 475                        default_argv = "on-demand";
 476                }
 477
 478                strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
 479                strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 480                strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
 481                git_dir = read_gitfile_gently(submodule_git_dir.buf);
 482                if (!git_dir)
 483                        git_dir = submodule_git_dir.buf;
 484                if (is_directory(git_dir)) {
 485                        if (!quiet)
 486                                printf("Fetching submodule %s%s\n", prefix, ce->name);
 487                        cp.dir = submodule_path.buf;
 488                        argv[default_argc] = default_argv;
 489                        argv[argc] = submodule_prefix.buf;
 490                        if (run_command(&cp))
 491                                result = 1;
 492                }
 493                strbuf_release(&submodule_path);
 494                strbuf_release(&submodule_git_dir);
 495                strbuf_release(&submodule_prefix);
 496        }
 497        free(argv);
 498out:
 499        string_list_clear(&changed_submodule_paths, 1);
 500        return result;
 501}
 502
 503unsigned is_submodule_modified(const char *path, int ignore_untracked)
 504{
 505        ssize_t len;
 506        struct child_process cp;
 507        const char *argv[] = {
 508                "status",
 509                "--porcelain",
 510                NULL,
 511                NULL,
 512        };
 513        struct strbuf buf = STRBUF_INIT;
 514        unsigned dirty_submodule = 0;
 515        const char *line, *next_line;
 516        const char *git_dir;
 517
 518        strbuf_addf(&buf, "%s/.git", path);
 519        git_dir = read_gitfile_gently(buf.buf);
 520        if (!git_dir)
 521                git_dir = buf.buf;
 522        if (!is_directory(git_dir)) {
 523                strbuf_release(&buf);
 524                /* The submodule is not checked out, so it is not modified */
 525                return 0;
 526
 527        }
 528        strbuf_reset(&buf);
 529
 530        if (ignore_untracked)
 531                argv[2] = "-uno";
 532
 533        memset(&cp, 0, sizeof(cp));
 534        cp.argv = argv;
 535        cp.env = local_repo_env;
 536        cp.git_cmd = 1;
 537        cp.no_stdin = 1;
 538        cp.out = -1;
 539        cp.dir = path;
 540        if (start_command(&cp))
 541                die("Could not run git status --porcelain");
 542
 543        len = strbuf_read(&buf, cp.out, 1024);
 544        line = buf.buf;
 545        while (len > 2) {
 546                if ((line[0] == '?') && (line[1] == '?')) {
 547                        dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
 548                        if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 549                                break;
 550                } else {
 551                        dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
 552                        if (ignore_untracked ||
 553                            (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
 554                                break;
 555                }
 556                next_line = strchr(line, '\n');
 557                if (!next_line)
 558                        break;
 559                next_line++;
 560                len -= (next_line - line);
 561                line = next_line;
 562        }
 563        close(cp.out);
 564
 565        if (finish_command(&cp))
 566                die("git status --porcelain failed");
 567
 568        strbuf_release(&buf);
 569        return dirty_submodule;
 570}
 571
 572static int find_first_merges(struct object_array *result, const char *path,
 573                struct commit *a, struct commit *b)
 574{
 575        int i, j;
 576        struct object_array merges;
 577        struct commit *commit;
 578        int contains_another;
 579
 580        char merged_revision[42];
 581        const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
 582                                   "--all", merged_revision, NULL };
 583        struct rev_info revs;
 584        struct setup_revision_opt rev_opts;
 585
 586        memset(&merges, 0, sizeof(merges));
 587        memset(result, 0, sizeof(struct object_array));
 588        memset(&rev_opts, 0, sizeof(rev_opts));
 589
 590        /* get all revisions that merge commit a */
 591        snprintf(merged_revision, sizeof(merged_revision), "^%s",
 592                        sha1_to_hex(a->object.sha1));
 593        init_revisions(&revs, NULL);
 594        rev_opts.submodule = path;
 595        setup_revisions(sizeof(rev_args)/sizeof(char *)-1, rev_args, &revs, &rev_opts);
 596
 597        /* save all revisions from the above list that contain b */
 598        if (prepare_revision_walk(&revs))
 599                die("revision walk setup failed");
 600        while ((commit = get_revision(&revs)) != NULL) {
 601                struct object *o = &(commit->object);
 602                if (in_merge_bases(b, &commit, 1))
 603                        add_object_array(o, NULL, &merges);
 604        }
 605
 606        /* Now we've got all merges that contain a and b. Prune all
 607         * merges that contain another found merge and save them in
 608         * result.
 609         */
 610        for (i = 0; i < merges.nr; i++) {
 611                struct commit *m1 = (struct commit *) merges.objects[i].item;
 612
 613                contains_another = 0;
 614                for (j = 0; j < merges.nr; j++) {
 615                        struct commit *m2 = (struct commit *) merges.objects[j].item;
 616                        if (i != j && in_merge_bases(m2, &m1, 1)) {
 617                                contains_another = 1;
 618                                break;
 619                        }
 620                }
 621
 622                if (!contains_another)
 623                        add_object_array(merges.objects[i].item,
 624                                         merges.objects[i].name, result);
 625        }
 626
 627        free(merges.objects);
 628        return result->nr;
 629}
 630
 631static void print_commit(struct commit *commit)
 632{
 633        struct strbuf sb = STRBUF_INIT;
 634        struct pretty_print_context ctx = {0};
 635        ctx.date_mode = DATE_NORMAL;
 636        format_commit_message(commit, " %h: %m %s", &sb, &ctx);
 637        fprintf(stderr, "%s\n", sb.buf);
 638        strbuf_release(&sb);
 639}
 640
 641#define MERGE_WARNING(path, msg) \
 642        warning("Failed to merge submodule %s (%s)", path, msg);
 643
 644int merge_submodule(unsigned char result[20], const char *path,
 645                    const unsigned char base[20], const unsigned char a[20],
 646                    const unsigned char b[20])
 647{
 648        struct commit *commit_base, *commit_a, *commit_b;
 649        int parent_count;
 650        struct object_array merges;
 651
 652        int i;
 653
 654        /* store a in result in case we fail */
 655        hashcpy(result, a);
 656
 657        /* we can not handle deletion conflicts */
 658        if (is_null_sha1(base))
 659                return 0;
 660        if (is_null_sha1(a))
 661                return 0;
 662        if (is_null_sha1(b))
 663                return 0;
 664
 665        if (add_submodule_odb(path)) {
 666                MERGE_WARNING(path, "not checked out");
 667                return 0;
 668        }
 669
 670        if (!(commit_base = lookup_commit_reference(base)) ||
 671            !(commit_a = lookup_commit_reference(a)) ||
 672            !(commit_b = lookup_commit_reference(b))) {
 673                MERGE_WARNING(path, "commits not present");
 674                return 0;
 675        }
 676
 677        /* check whether both changes are forward */
 678        if (!in_merge_bases(commit_base, &commit_a, 1) ||
 679            !in_merge_bases(commit_base, &commit_b, 1)) {
 680                MERGE_WARNING(path, "commits don't follow merge-base");
 681                return 0;
 682        }
 683
 684        /* Case #1: a is contained in b or vice versa */
 685        if (in_merge_bases(commit_a, &commit_b, 1)) {
 686                hashcpy(result, b);
 687                return 1;
 688        }
 689        if (in_merge_bases(commit_b, &commit_a, 1)) {
 690                hashcpy(result, a);
 691                return 1;
 692        }
 693
 694        /*
 695         * Case #2: There are one or more merges that contain a and b in
 696         * the submodule. If there is only one, then present it as a
 697         * suggestion to the user, but leave it marked unmerged so the
 698         * user needs to confirm the resolution.
 699         */
 700
 701        /* find commit which merges them */
 702        parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 703        switch (parent_count) {
 704        case 0:
 705                MERGE_WARNING(path, "merge following commits not found");
 706                break;
 707
 708        case 1:
 709                MERGE_WARNING(path, "not fast-forward");
 710                fprintf(stderr, "Found a possible merge resolution "
 711                                "for the submodule:\n");
 712                print_commit((struct commit *) merges.objects[0].item);
 713                fprintf(stderr,
 714                        "If this is correct simply add it to the index "
 715                        "for example\n"
 716                        "by using:\n\n"
 717                        "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
 718                        "which will accept this suggestion.\n",
 719                        sha1_to_hex(merges.objects[0].item->sha1), path);
 720                break;
 721
 722        default:
 723                MERGE_WARNING(path, "multiple merges found");
 724                for (i = 0; i < merges.nr; i++)
 725                        print_commit((struct commit *) merges.objects[i].item);
 726        }
 727
 728        free(merges.objects);
 729        return 0;
 730}