submodule.con commit Merge branch 'rc/histogram-diff' (b648557)
   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(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 has_remote(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 312{
 313        return 1;
 314}
 315
 316static int submodule_needs_pushing(const char *path, const unsigned char sha1[20])
 317{
 318        if (add_submodule_odb(path) || !lookup_commit_reference(sha1))
 319                return 0;
 320
 321        if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 322                struct child_process cp;
 323                const char *argv[] = {"rev-list", NULL, "--not", "--remotes", "-n", "1" , NULL};
 324                struct strbuf buf = STRBUF_INIT;
 325                int needs_pushing = 0;
 326
 327                argv[1] = sha1_to_hex(sha1);
 328                memset(&cp, 0, sizeof(cp));
 329                cp.argv = argv;
 330                cp.env = local_repo_env;
 331                cp.git_cmd = 1;
 332                cp.no_stdin = 1;
 333                cp.out = -1;
 334                cp.dir = path;
 335                if (start_command(&cp))
 336                        die("Could not run 'git rev-list %s --not --remotes -n 1' command in submodule %s",
 337                                sha1_to_hex(sha1), path);
 338                if (strbuf_read(&buf, cp.out, 41))
 339                        needs_pushing = 1;
 340                finish_command(&cp);
 341                close(cp.out);
 342                strbuf_release(&buf);
 343                return needs_pushing;
 344        }
 345
 346        return 0;
 347}
 348
 349static void collect_submodules_from_diff(struct diff_queue_struct *q,
 350                                         struct diff_options *options,
 351                                         void *data)
 352{
 353        int i;
 354        int *needs_pushing = data;
 355
 356        for (i = 0; i < q->nr; i++) {
 357                struct diff_filepair *p = q->queue[i];
 358                if (!S_ISGITLINK(p->two->mode))
 359                        continue;
 360                if (submodule_needs_pushing(p->two->path, p->two->sha1)) {
 361                        *needs_pushing = 1;
 362                        break;
 363                }
 364        }
 365}
 366
 367
 368static void commit_need_pushing(struct commit *commit, struct commit_list *parent, int *needs_pushing)
 369{
 370        const unsigned char (*parents)[20];
 371        unsigned int i, n;
 372        struct rev_info rev;
 373
 374        n = commit_list_count(parent);
 375        parents = xmalloc(n * sizeof(*parents));
 376
 377        for (i = 0; i < n; i++) {
 378                hashcpy((unsigned char *)(parents + i), parent->item->object.sha1);
 379                parent = parent->next;
 380        }
 381
 382        init_revisions(&rev, NULL);
 383        rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 384        rev.diffopt.format_callback = collect_submodules_from_diff;
 385        rev.diffopt.format_callback_data = needs_pushing;
 386        diff_tree_combined(commit->object.sha1, parents, n, 1, &rev);
 387
 388        free(parents);
 389}
 390
 391int check_submodule_needs_pushing(unsigned char new_sha1[20], const char *remotes_name)
 392{
 393        struct rev_info rev;
 394        struct commit *commit;
 395        const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
 396        int argc = ARRAY_SIZE(argv) - 1;
 397        char *sha1_copy;
 398        int needs_pushing = 0;
 399        struct strbuf remotes_arg = STRBUF_INIT;
 400
 401        strbuf_addf(&remotes_arg, "--remotes=%s", remotes_name);
 402        init_revisions(&rev, NULL);
 403        sha1_copy = xstrdup(sha1_to_hex(new_sha1));
 404        argv[1] = sha1_copy;
 405        argv[3] = remotes_arg.buf;
 406        setup_revisions(argc, argv, &rev, NULL);
 407        if (prepare_revision_walk(&rev))
 408                die("revision walk setup failed");
 409
 410        while ((commit = get_revision(&rev)) && !needs_pushing)
 411                commit_need_pushing(commit, commit->parents, &needs_pushing);
 412
 413        free(sha1_copy);
 414        strbuf_release(&remotes_arg);
 415
 416        return needs_pushing;
 417}
 418
 419static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 420{
 421        int is_present = 0;
 422        if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
 423                /* Even if the submodule is checked out and the commit is
 424                 * present, make sure it is reachable from a ref. */
 425                struct child_process cp;
 426                const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
 427                struct strbuf buf = STRBUF_INIT;
 428
 429                argv[3] = sha1_to_hex(sha1);
 430                memset(&cp, 0, sizeof(cp));
 431                cp.argv = argv;
 432                cp.env = local_repo_env;
 433                cp.git_cmd = 1;
 434                cp.no_stdin = 1;
 435                cp.out = -1;
 436                cp.dir = path;
 437                if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
 438                        is_present = 1;
 439
 440                close(cp.out);
 441                strbuf_release(&buf);
 442        }
 443        return is_present;
 444}
 445
 446static void submodule_collect_changed_cb(struct diff_queue_struct *q,
 447                                         struct diff_options *options,
 448                                         void *data)
 449{
 450        int i;
 451        for (i = 0; i < q->nr; i++) {
 452                struct diff_filepair *p = q->queue[i];
 453                if (!S_ISGITLINK(p->two->mode))
 454                        continue;
 455
 456                if (S_ISGITLINK(p->one->mode)) {
 457                        /* NEEDSWORK: We should honor the name configured in
 458                         * the .gitmodules file of the commit we are examining
 459                         * here to be able to correctly follow submodules
 460                         * being moved around. */
 461                        struct string_list_item *path;
 462                        path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
 463                        if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
 464                                string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
 465                } else {
 466                        /* Submodule is new or was moved here */
 467                        /* NEEDSWORK: When the .git directories of submodules
 468                         * live inside the superprojects .git directory some
 469                         * day we should fetch new submodules directly into
 470                         * that location too when config or options request
 471                         * that so they can be checked out from there. */
 472                        continue;
 473                }
 474        }
 475}
 476
 477void check_for_new_submodule_commits(unsigned char new_sha1[20])
 478{
 479        struct rev_info rev;
 480        struct commit *commit;
 481        const char *argv[] = {NULL, NULL, "--not", "--all", NULL};
 482        int argc = ARRAY_SIZE(argv) - 1;
 483
 484        init_revisions(&rev, NULL);
 485        argv[1] = xstrdup(sha1_to_hex(new_sha1));
 486        setup_revisions(argc, argv, &rev, NULL);
 487        if (prepare_revision_walk(&rev))
 488                die("revision walk setup failed");
 489
 490        /*
 491         * Collect all submodules (whether checked out or not) for which new
 492         * commits have been recorded upstream in "changed_submodule_paths".
 493         */
 494        while ((commit = get_revision(&rev))) {
 495                struct commit_list *parent = commit->parents;
 496                while (parent) {
 497                        struct diff_options diff_opts;
 498                        diff_setup(&diff_opts);
 499                        DIFF_OPT_SET(&diff_opts, RECURSIVE);
 500                        diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
 501                        diff_opts.format_callback = submodule_collect_changed_cb;
 502                        if (diff_setup_done(&diff_opts) < 0)
 503                                die("diff_setup_done failed");
 504                        diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
 505                        diffcore_std(&diff_opts);
 506                        diff_flush(&diff_opts);
 507                        parent = parent->next;
 508                }
 509        }
 510        free((char *)argv[1]);
 511}
 512
 513int fetch_populated_submodules(int num_options, const char **options,
 514                               const char *prefix, int command_line_option,
 515                               int quiet)
 516{
 517        int i, result = 0, argc = 0, default_argc;
 518        struct child_process cp;
 519        const char **argv;
 520        struct string_list_item *name_for_path;
 521        const char *work_tree = get_git_work_tree();
 522        if (!work_tree)
 523                goto out;
 524
 525        if (!the_index.initialized)
 526                if (read_cache() < 0)
 527                        die("index file corrupt");
 528
 529        /* 6: "fetch" (options) --recurse-submodules-default default "--submodule-prefix" prefix NULL */
 530        argv = xcalloc(num_options + 6, sizeof(const char *));
 531        argv[argc++] = "fetch";
 532        for (i = 0; i < num_options; i++)
 533                argv[argc++] = options[i];
 534        argv[argc++] = "--recurse-submodules-default";
 535        default_argc = argc++;
 536        argv[argc++] = "--submodule-prefix";
 537
 538        memset(&cp, 0, sizeof(cp));
 539        cp.argv = argv;
 540        cp.env = local_repo_env;
 541        cp.git_cmd = 1;
 542        cp.no_stdin = 1;
 543
 544        for (i = 0; i < active_nr; i++) {
 545                struct strbuf submodule_path = STRBUF_INIT;
 546                struct strbuf submodule_git_dir = STRBUF_INIT;
 547                struct strbuf submodule_prefix = STRBUF_INIT;
 548                struct cache_entry *ce = active_cache[i];
 549                const char *git_dir, *name, *default_argv;
 550
 551                if (!S_ISGITLINK(ce->ce_mode))
 552                        continue;
 553
 554                name = ce->name;
 555                name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
 556                if (name_for_path)
 557                        name = name_for_path->util;
 558
 559                default_argv = "yes";
 560                if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
 561                        struct string_list_item *fetch_recurse_submodules_option;
 562                        fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
 563                        if (fetch_recurse_submodules_option) {
 564                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
 565                                        continue;
 566                                if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
 567                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 568                                                continue;
 569                                        default_argv = "on-demand";
 570                                }
 571                        } else {
 572                                if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
 573                                    gitmodules_is_unmerged)
 574                                        continue;
 575                                if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
 576                                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 577                                                continue;
 578                                        default_argv = "on-demand";
 579                                }
 580                        }
 581                } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
 582                        if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 583                                continue;
 584                        default_argv = "on-demand";
 585                }
 586
 587                strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
 588                strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 589                strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
 590                git_dir = read_gitfile(submodule_git_dir.buf);
 591                if (!git_dir)
 592                        git_dir = submodule_git_dir.buf;
 593                if (is_directory(git_dir)) {
 594                        if (!quiet)
 595                                printf("Fetching submodule %s%s\n", prefix, ce->name);
 596                        cp.dir = submodule_path.buf;
 597                        argv[default_argc] = default_argv;
 598                        argv[argc] = submodule_prefix.buf;
 599                        if (run_command(&cp))
 600                                result = 1;
 601                }
 602                strbuf_release(&submodule_path);
 603                strbuf_release(&submodule_git_dir);
 604                strbuf_release(&submodule_prefix);
 605        }
 606        free(argv);
 607out:
 608        string_list_clear(&changed_submodule_paths, 1);
 609        return result;
 610}
 611
 612unsigned is_submodule_modified(const char *path, int ignore_untracked)
 613{
 614        ssize_t len;
 615        struct child_process cp;
 616        const char *argv[] = {
 617                "status",
 618                "--porcelain",
 619                NULL,
 620                NULL,
 621        };
 622        struct strbuf buf = STRBUF_INIT;
 623        unsigned dirty_submodule = 0;
 624        const char *line, *next_line;
 625        const char *git_dir;
 626
 627        strbuf_addf(&buf, "%s/.git", path);
 628        git_dir = read_gitfile(buf.buf);
 629        if (!git_dir)
 630                git_dir = buf.buf;
 631        if (!is_directory(git_dir)) {
 632                strbuf_release(&buf);
 633                /* The submodule is not checked out, so it is not modified */
 634                return 0;
 635
 636        }
 637        strbuf_reset(&buf);
 638
 639        if (ignore_untracked)
 640                argv[2] = "-uno";
 641
 642        memset(&cp, 0, sizeof(cp));
 643        cp.argv = argv;
 644        cp.env = local_repo_env;
 645        cp.git_cmd = 1;
 646        cp.no_stdin = 1;
 647        cp.out = -1;
 648        cp.dir = path;
 649        if (start_command(&cp))
 650                die("Could not run git status --porcelain");
 651
 652        len = strbuf_read(&buf, cp.out, 1024);
 653        line = buf.buf;
 654        while (len > 2) {
 655                if ((line[0] == '?') && (line[1] == '?')) {
 656                        dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
 657                        if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 658                                break;
 659                } else {
 660                        dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
 661                        if (ignore_untracked ||
 662                            (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
 663                                break;
 664                }
 665                next_line = strchr(line, '\n');
 666                if (!next_line)
 667                        break;
 668                next_line++;
 669                len -= (next_line - line);
 670                line = next_line;
 671        }
 672        close(cp.out);
 673
 674        if (finish_command(&cp))
 675                die("git status --porcelain failed");
 676
 677        strbuf_release(&buf);
 678        return dirty_submodule;
 679}
 680
 681static int find_first_merges(struct object_array *result, const char *path,
 682                struct commit *a, struct commit *b)
 683{
 684        int i, j;
 685        struct object_array merges;
 686        struct commit *commit;
 687        int contains_another;
 688
 689        char merged_revision[42];
 690        const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
 691                                   "--all", merged_revision, NULL };
 692        struct rev_info revs;
 693        struct setup_revision_opt rev_opts;
 694
 695        memset(&merges, 0, sizeof(merges));
 696        memset(result, 0, sizeof(struct object_array));
 697        memset(&rev_opts, 0, sizeof(rev_opts));
 698
 699        /* get all revisions that merge commit a */
 700        snprintf(merged_revision, sizeof(merged_revision), "^%s",
 701                        sha1_to_hex(a->object.sha1));
 702        init_revisions(&revs, NULL);
 703        rev_opts.submodule = path;
 704        setup_revisions(sizeof(rev_args)/sizeof(char *)-1, rev_args, &revs, &rev_opts);
 705
 706        /* save all revisions from the above list that contain b */
 707        if (prepare_revision_walk(&revs))
 708                die("revision walk setup failed");
 709        while ((commit = get_revision(&revs)) != NULL) {
 710                struct object *o = &(commit->object);
 711                if (in_merge_bases(b, &commit, 1))
 712                        add_object_array(o, NULL, &merges);
 713        }
 714
 715        /* Now we've got all merges that contain a and b. Prune all
 716         * merges that contain another found merge and save them in
 717         * result.
 718         */
 719        for (i = 0; i < merges.nr; i++) {
 720                struct commit *m1 = (struct commit *) merges.objects[i].item;
 721
 722                contains_another = 0;
 723                for (j = 0; j < merges.nr; j++) {
 724                        struct commit *m2 = (struct commit *) merges.objects[j].item;
 725                        if (i != j && in_merge_bases(m2, &m1, 1)) {
 726                                contains_another = 1;
 727                                break;
 728                        }
 729                }
 730
 731                if (!contains_another)
 732                        add_object_array(merges.objects[i].item,
 733                                         merges.objects[i].name, result);
 734        }
 735
 736        free(merges.objects);
 737        return result->nr;
 738}
 739
 740static void print_commit(struct commit *commit)
 741{
 742        struct strbuf sb = STRBUF_INIT;
 743        struct pretty_print_context ctx = {0};
 744        ctx.date_mode = DATE_NORMAL;
 745        format_commit_message(commit, " %h: %m %s", &sb, &ctx);
 746        fprintf(stderr, "%s\n", sb.buf);
 747        strbuf_release(&sb);
 748}
 749
 750#define MERGE_WARNING(path, msg) \
 751        warning("Failed to merge submodule %s (%s)", path, msg);
 752
 753int merge_submodule(unsigned char result[20], const char *path,
 754                    const unsigned char base[20], const unsigned char a[20],
 755                    const unsigned char b[20])
 756{
 757        struct commit *commit_base, *commit_a, *commit_b;
 758        int parent_count;
 759        struct object_array merges;
 760
 761        int i;
 762
 763        /* store a in result in case we fail */
 764        hashcpy(result, a);
 765
 766        /* we can not handle deletion conflicts */
 767        if (is_null_sha1(base))
 768                return 0;
 769        if (is_null_sha1(a))
 770                return 0;
 771        if (is_null_sha1(b))
 772                return 0;
 773
 774        if (add_submodule_odb(path)) {
 775                MERGE_WARNING(path, "not checked out");
 776                return 0;
 777        }
 778
 779        if (!(commit_base = lookup_commit_reference(base)) ||
 780            !(commit_a = lookup_commit_reference(a)) ||
 781            !(commit_b = lookup_commit_reference(b))) {
 782                MERGE_WARNING(path, "commits not present");
 783                return 0;
 784        }
 785
 786        /* check whether both changes are forward */
 787        if (!in_merge_bases(commit_base, &commit_a, 1) ||
 788            !in_merge_bases(commit_base, &commit_b, 1)) {
 789                MERGE_WARNING(path, "commits don't follow merge-base");
 790                return 0;
 791        }
 792
 793        /* Case #1: a is contained in b or vice versa */
 794        if (in_merge_bases(commit_a, &commit_b, 1)) {
 795                hashcpy(result, b);
 796                return 1;
 797        }
 798        if (in_merge_bases(commit_b, &commit_a, 1)) {
 799                hashcpy(result, a);
 800                return 1;
 801        }
 802
 803        /*
 804         * Case #2: There are one or more merges that contain a and b in
 805         * the submodule. If there is only one, then present it as a
 806         * suggestion to the user, but leave it marked unmerged so the
 807         * user needs to confirm the resolution.
 808         */
 809
 810        /* find commit which merges them */
 811        parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 812        switch (parent_count) {
 813        case 0:
 814                MERGE_WARNING(path, "merge following commits not found");
 815                break;
 816
 817        case 1:
 818                MERGE_WARNING(path, "not fast-forward");
 819                fprintf(stderr, "Found a possible merge resolution "
 820                                "for the submodule:\n");
 821                print_commit((struct commit *) merges.objects[0].item);
 822                fprintf(stderr,
 823                        "If this is correct simply add it to the index "
 824                        "for example\n"
 825                        "by using:\n\n"
 826                        "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
 827                        "which will accept this suggestion.\n",
 828                        sha1_to_hex(merges.objects[0].item->sha1), path);
 829                break;
 830
 831        default:
 832                MERGE_WARNING(path, "multiple merges found");
 833                for (i = 0; i < merges.nr; i++)
 834                        print_commit((struct commit *) merges.objects[i].item);
 835        }
 836
 837        free(merges.objects);
 838        return 0;
 839}