submodule.c

   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 #include "sha1-array.h"
  12 #include "argv-array.h"
  13
  14 static struct string_list config_name_for_path;
  15 static struct string_list config_fetch_recurse_submodules_for_name;
  16 static struct string_list config_ignore_for_name;
  17 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
  18 static struct string_list changed_submodule_paths;
  19 static int initialized_fetch_ref_tips;
  20 static struct sha1_array ref_tips_before_fetch;
  21 static struct sha1_array ref_tips_after_fetch;
  22
  23 /*
  24  * The following flag is set if the .gitmodules file is unmerged. We then
  25  * disable recursion for all submodules where .git/config doesn't have a
  26  * matching config entry because we can't guess what might be configured in
  27  * .gitmodules unless the user resolves the conflict. When a command line
  28  * option is given (which always overrides configuration) this flag will be
  29  * ignored.
  30  */
  31 static int gitmodules_is_unmerged;
  32
  33 static int add_submodule_odb(const char *path)
  34 {
  35         struct strbuf objects_directory = STRBUF_INIT;
  36         struct alternate_object_database *alt_odb;
  37         int ret = 0;
  38         const char *git_dir;
  39
  40         strbuf_addf(&objects_directory, "%s/.git", path);
  41         git_dir = read_gitfile(objects_directory.buf);
  42         if (git_dir) {
  43                 strbuf_reset(&objects_directory);
  44                 strbuf_addstr(&objects_directory, git_dir);
  45         }
  46         strbuf_addstr(&objects_directory, "/objects/");
  47         if (!is_directory(objects_directory.buf)) {
  48                 ret = -1;
  49                 goto done;
  50         }
  51         /* avoid adding it twice */
  52         for (alt_odb = alt_odb_list; alt_odb; alt_odb = alt_odb->next)
  53                 if (alt_odb->name - alt_odb->base == objects_directory.len &&
  54                                 !strncmp(alt_odb->base, objects_directory.buf,
  55                                         objects_directory.len))
  56                         goto done;
  57
  58         alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
  59         alt_odb->next = alt_odb_list;
  60         strcpy(alt_odb->base, objects_directory.buf);
  61         alt_odb->name = alt_odb->base + objects_directory.len;
  62         alt_odb->name[2] = '/';
  63         alt_odb->name[40] = '\0';
  64         alt_odb->name[41] = '\0';
  65         alt_odb_list = alt_odb;
  66
  67         /* add possible alternates from the submodule */
  68         read_info_alternates(objects_directory.buf, 0);
  69         prepare_alt_odb();
  70 done:
  71         strbuf_release(&objects_directory);
  72         return ret;
  73 }
  74
  75 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
  76                                              const char *path)
  77 {
  78         struct string_list_item *path_option, *ignore_option;
  79         path_option = unsorted_string_list_lookup(&config_name_for_path, path);
  80         if (path_option) {
  81                 ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
  82                 if (ignore_option)
  83                         handle_ignore_submodules_arg(diffopt, ignore_option->util);
  84                 else if (gitmodules_is_unmerged)
  85                         DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
  86         }
  87 }
  88
  89 int submodule_config(const char *var, const char *value, void *cb)
  90 {
  91         if (!prefixcmp(var, "submodule."))
  92                 return parse_submodule_config_option(var, value);
  93         else if (!strcmp(var, "fetch.recursesubmodules")) {
  94                 config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
  95                 return 0;
  96         }
  97         return 0;
  98 }
  99
 100 void gitmodules_config(void)
 101 {
 102         const char *work_tree = get_git_work_tree();
 103         if (work_tree) {
 104                 struct strbuf gitmodules_path = STRBUF_INIT;
 105                 int pos;
 106                 strbuf_addstr(&gitmodules_path, work_tree);
 107                 strbuf_addstr(&gitmodules_path, "/.gitmodules");
 108                 if (read_cache() < 0)
 109                         die("index file corrupt");
 110                 pos = cache_name_pos(".gitmodules", 11);
 111                 if (pos < 0) { /* .gitmodules not found or isn't merged */
 112                         pos = -1 - pos;
 113                         if (active_nr > pos) {  /* there is a .gitmodules */
 114                                 const struct cache_entry *ce = active_cache[pos];
 115                                 if (ce_namelen(ce) == 11 &&
 116                                     !memcmp(ce->name, ".gitmodules", 11))
 117                                         gitmodules_is_unmerged = 1;
 118                         }
 119                 }
 120
 121                 if (!gitmodules_is_unmerged)
 122                         git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
 123                 strbuf_release(&gitmodules_path);
 124         }
 125 }
 126
 127 int parse_submodule_config_option(const char *var, const char *value)
 128 {
 129         int len;
 130         struct string_list_item *config;
 131         struct strbuf submodname = STRBUF_INIT;
 132
 133         var += 10;              /* Skip "submodule." */
 134
 135         len = strlen(var);
 136         if ((len > 5) && !strcmp(var + len - 5, ".path")) {
 137                 strbuf_add(&submodname, var, len - 5);
 138                 config = unsorted_string_list_lookup(&config_name_for_path, value);
 139                 if (config)
 140                         free(config->util);
 141                 else
 142                         config = string_list_append(&config_name_for_path, xstrdup(value));
 143                 config->util = strbuf_detach(&submodname, NULL);
 144                 strbuf_release(&submodname);
 145         } else if ((len > 23) && !strcmp(var + len - 23, ".fetchrecursesubmodules")) {
 146                 strbuf_add(&submodname, var, len - 23);
 147                 config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, submodname.buf);
 148                 if (!config)
 149                         config = string_list_append(&config_fetch_recurse_submodules_for_name,
 150                                                     strbuf_detach(&submodname, NULL));
 151                 config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
 152                 strbuf_release(&submodname);
 153         } else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
 154                 if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
 155                     strcmp(value, "all") && strcmp(value, "none")) {
 156                         warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
 157                         return 0;
 158                 }
 159
 160                 strbuf_add(&submodname, var, len - 7);
 161                 config = unsorted_string_list_lookup(&config_ignore_for_name, submodname.buf);
 162                 if (config)
 163                         free(config->util);
 164                 else
 165                         config = string_list_append(&config_ignore_for_name,
 166                                                     strbuf_detach(&submodname, NULL));
 167                 strbuf_release(&submodname);
 168                 config->util = xstrdup(value);
 169                 return 0;
 170         }
 171         return 0;
 172 }
 173
 174 void handle_ignore_submodules_arg(struct diff_options *diffopt,
 175                                   const char *arg)
 176 {
 177         DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
 178         DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 179         DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
 180
 181         if (!strcmp(arg, "all"))
 182                 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 183         else if (!strcmp(arg, "untracked"))
 184                 DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 185         else if (!strcmp(arg, "dirty"))
 186                 DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
 187         else if (strcmp(arg, "none"))
 188                 die("bad --ignore-submodules argument: %s", arg);
 189 }
 190
 191 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 192                 struct commit *left, struct commit *right,
 193                 int *fast_forward, int *fast_backward)
 194 {
 195         struct commit_list *merge_bases, *list;
 196
 197         init_revisions(rev, NULL);
 198         setup_revisions(0, NULL, rev, NULL);
 199         rev->left_right = 1;
 200         rev->first_parent_only = 1;
 201         left->object.flags |= SYMMETRIC_LEFT;
 202         add_pending_object(rev, &left->object, path);
 203         add_pending_object(rev, &right->object, path);
 204         merge_bases = get_merge_bases(left, right, 1);
 205         if (merge_bases) {
 206                 if (merge_bases->item == left)
 207                         *fast_forward = 1;
 208                 else if (merge_bases->item == right)
 209                         *fast_backward = 1;
 210         }
 211         for (list = merge_bases; list; list = list->next) {
 212                 list->item->object.flags |= UNINTERESTING;
 213                 add_pending_object(rev, &list->item->object,
 214                         sha1_to_hex(list->item->object.sha1));
 215         }
 216         return prepare_revision_walk(rev);
 217 }
 218
 219 static void print_submodule_summary(struct rev_info *rev, FILE *f,
 220                 const char *del, const char *add, const char *reset)
 221 {
 222         static const char format[] = "  %m %s";
 223         struct strbuf sb = STRBUF_INIT;
 224         struct commit *commit;
 225
 226         while ((commit = get_revision(rev))) {
 227                 struct pretty_print_context ctx = {0};
 228                 ctx.date_mode = rev->date_mode;
 229                 strbuf_setlen(&sb, 0);
 230                 if (commit->object.flags & SYMMETRIC_LEFT) {
 231                         if (del)
 232                                 strbuf_addstr(&sb, del);
 233                 }
 234                 else if (add)
 235                         strbuf_addstr(&sb, add);
 236                 format_commit_message(commit, format, &sb, &ctx);
 237                 if (reset)
 238                         strbuf_addstr(&sb, reset);
 239                 strbuf_addch(&sb, '\n');
 240                 fprintf(f, "%s", sb.buf);
 241         }
 242         strbuf_release(&sb);
 243 }
 244
 245 int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
 246 {
 247         switch (git_config_maybe_bool(opt, arg)) {
 248         case 1:
 249                 return RECURSE_SUBMODULES_ON;
 250         case 0:
 251                 return RECURSE_SUBMODULES_OFF;
 252         default:
 253                 if (!strcmp(arg, "on-demand"))
 254                         return RECURSE_SUBMODULES_ON_DEMAND;
 255                 die("bad %s argument: %s", opt, arg);
 256         }
 257 }
 258
 259 void show_submodule_summary(FILE *f, const char *path,
 260                 unsigned char one[20], unsigned char two[20],
 261                 unsigned dirty_submodule,
 262                 const char *del, const char *add, const char *reset)
 263 {
 264         struct rev_info rev;
 265         struct commit *left = left, *right = right;
 266         const char *message = NULL;
 267         struct strbuf sb = STRBUF_INIT;
 268         int fast_forward = 0, fast_backward = 0;
 269
 270         if (is_null_sha1(two))
 271                 message = "(submodule deleted)";
 272         else if (add_submodule_odb(path))
 273                 message = "(not checked out)";
 274         else if (is_null_sha1(one))
 275                 message = "(new submodule)";
 276         else if (!(left = lookup_commit_reference(one)) ||
 277                  !(right = lookup_commit_reference(two)))
 278                 message = "(commits not present)";
 279
 280         if (!message &&
 281             prepare_submodule_summary(&rev, path, left, right,
 282                                         &fast_forward, &fast_backward))
 283                 message = "(revision walker failed)";
 284
 285         if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
 286                 fprintf(f, "Submodule %s contains untracked content\n", path);
 287         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 288                 fprintf(f, "Submodule %s contains modified content\n", path);
 289
 290         if (!hashcmp(one, two)) {
 291                 strbuf_release(&sb);
 292                 return;
 293         }
 294
 295         strbuf_addf(&sb, "Submodule %s %s..", path,
 296                         find_unique_abbrev(one, DEFAULT_ABBREV));
 297         if (!fast_backward && !fast_forward)
 298                 strbuf_addch(&sb, '.');
 299         strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
 300         if (message)
 301                 strbuf_addf(&sb, " %s\n", message);
 302         else
 303                 strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
 304         fwrite(sb.buf, sb.len, 1, f);
 305
 306         if (!message) {
 307                 print_submodule_summary(&rev, f, del, add, reset);
 308                 clear_commit_marks(left, ~0);
 309                 clear_commit_marks(right, ~0);
 310         }
 311
 312         strbuf_release(&sb);
 313 }
 314
 315 void set_config_fetch_recurse_submodules(int value)
 316 {
 317         config_fetch_recurse_submodules = value;
 318 }
 319
 320 static int has_remote(const char *refname, const unsigned char *sha1, int flags, void *cb_data)
 321 {
 322         return 1;
 323 }
 324
 325 static int submodule_needs_pushing(const char *path, const unsigned char sha1[20])
 326 {
 327         if (add_submodule_odb(path) || !lookup_commit_reference(sha1))
 328                 return 0;
 329
 330         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 331                 struct child_process cp;
 332                 const char *argv[] = {"rev-list", NULL, "--not", "--remotes", "-n", "1" , NULL};
 333                 struct strbuf buf = STRBUF_INIT;
 334                 int needs_pushing = 0;
 335
 336                 argv[1] = sha1_to_hex(sha1);
 337                 memset(&cp, 0, sizeof(cp));
 338                 cp.argv = argv;
 339                 cp.env = local_repo_env;
 340                 cp.git_cmd = 1;
 341                 cp.no_stdin = 1;
 342                 cp.out = -1;
 343                 cp.dir = path;
 344                 if (start_command(&cp))
 345                         die("Could not run 'git rev-list %s --not --remotes -n 1' command in submodule %s",
 346                                 sha1_to_hex(sha1), path);
 347                 if (strbuf_read(&buf, cp.out, 41))
 348                         needs_pushing = 1;
 349                 finish_command(&cp);
 350                 close(cp.out);
 351                 strbuf_release(&buf);
 352                 return needs_pushing;
 353         }
 354
 355         return 0;
 356 }
 357
 358 static void collect_submodules_from_diff(struct diff_queue_struct *q,
 359                                          struct diff_options *options,
 360                                          void *data)
 361 {
 362         int i;
 363         int *needs_pushing = data;
 364
 365         for (i = 0; i < q->nr; i++) {
 366                 struct diff_filepair *p = q->queue[i];
 367                 if (!S_ISGITLINK(p->two->mode))
 368                         continue;
 369                 if (submodule_needs_pushing(p->two->path, p->two->sha1)) {
 370                         *needs_pushing = 1;
 371                         break;
 372                 }
 373         }
 374 }
 375
 376
 377 static void commit_need_pushing(struct commit *commit, int *needs_pushing)
 378 {
 379         struct rev_info rev;
 380
 381         init_revisions(&rev, NULL);
 382         rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 383         rev.diffopt.format_callback = collect_submodules_from_diff;
 384         rev.diffopt.format_callback_data = needs_pushing;
 385         diff_tree_combined_merge(commit, 1, &rev);
 386 }
 387
 388 int check_submodule_needs_pushing(unsigned char new_sha1[20], const char *remotes_name)
 389 {
 390         struct rev_info rev;
 391         struct commit *commit;
 392         const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
 393         int argc = ARRAY_SIZE(argv) - 1;
 394         char *sha1_copy;
 395         int needs_pushing = 0;
 396         struct strbuf remotes_arg = STRBUF_INIT;
 397
 398         strbuf_addf(&remotes_arg, "--remotes=%s", remotes_name);
 399         init_revisions(&rev, NULL);
 400         sha1_copy = xstrdup(sha1_to_hex(new_sha1));
 401         argv[1] = sha1_copy;
 402         argv[3] = remotes_arg.buf;
 403         setup_revisions(argc, argv, &rev, NULL);
 404         if (prepare_revision_walk(&rev))
 405                 die("revision walk setup failed");
 406
 407         while ((commit = get_revision(&rev)) && !needs_pushing)
 408                 commit_need_pushing(commit, &needs_pushing);
 409
 410         free(sha1_copy);
 411         strbuf_release(&remotes_arg);
 412
 413         return needs_pushing;
 414 }
 415
 416 static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
 417 {
 418         int is_present = 0;
 419         if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
 420                 /* Even if the submodule is checked out and the commit is
 421                  * present, make sure it is reachable from a ref. */
 422                 struct child_process cp;
 423                 const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
 424                 struct strbuf buf = STRBUF_INIT;
 425
 426                 argv[3] = sha1_to_hex(sha1);
 427                 memset(&cp, 0, sizeof(cp));
 428                 cp.argv = argv;
 429                 cp.env = local_repo_env;
 430                 cp.git_cmd = 1;
 431                 cp.no_stdin = 1;
 432                 cp.out = -1;
 433                 cp.dir = path;
 434                 if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
 435                         is_present = 1;
 436
 437                 close(cp.out);
 438                 strbuf_release(&buf);
 439         }
 440         return is_present;
 441 }
 442
 443 static void submodule_collect_changed_cb(struct diff_queue_struct *q,
 444                                          struct diff_options *options,
 445                                          void *data)
 446 {
 447         int i;
 448         for (i = 0; i < q->nr; i++) {
 449                 struct diff_filepair *p = q->queue[i];
 450                 if (!S_ISGITLINK(p->two->mode))
 451                         continue;
 452
 453                 if (S_ISGITLINK(p->one->mode)) {
 454                         /* NEEDSWORK: We should honor the name configured in
 455                          * the .gitmodules file of the commit we are examining
 456                          * here to be able to correctly follow submodules
 457                          * being moved around. */
 458                         struct string_list_item *path;
 459                         path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
 460                         if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
 461                                 string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
 462                 } else {
 463                         /* Submodule is new or was moved here */
 464                         /* NEEDSWORK: When the .git directories of submodules
 465                          * live inside the superprojects .git directory some
 466                          * day we should fetch new submodules directly into
 467                          * that location too when config or options request
 468                          * that so they can be checked out from there. */
 469                         continue;
 470                 }
 471         }
 472 }
 473
 474 static int add_sha1_to_array(const char *ref, const unsigned char *sha1,
 475                              int flags, void *data)
 476 {
 477         sha1_array_append(data, sha1);
 478         return 0;
 479 }
 480
 481 void check_for_new_submodule_commits(unsigned char new_sha1[20])
 482 {
 483         if (!initialized_fetch_ref_tips) {
 484                 for_each_ref(add_sha1_to_array, &ref_tips_before_fetch);
 485                 initialized_fetch_ref_tips = 1;
 486         }
 487
 488         sha1_array_append(&ref_tips_after_fetch, new_sha1);
 489 }
 490
 491 static void add_sha1_to_argv(const unsigned char sha1[20], void *data)
 492 {
 493         argv_array_push(data, sha1_to_hex(sha1));
 494 }
 495
 496 static void calculate_changed_submodule_paths(void)
 497 {
 498         struct rev_info rev;
 499         struct commit *commit;
 500         struct argv_array argv = ARGV_ARRAY_INIT;
 501
 502         /* No need to check if there are no submodules configured */
 503         if (!config_name_for_path.nr)
 504                 return;
 505
 506         init_revisions(&rev, NULL);
 507         argv_array_push(&argv, "--"); /* argv[0] program name */
 508         sha1_array_for_each_unique(&ref_tips_after_fetch,
 509                                    add_sha1_to_argv, &argv);
 510         argv_array_push(&argv, "--not");
 511         sha1_array_for_each_unique(&ref_tips_before_fetch,
 512                                    add_sha1_to_argv, &argv);
 513         setup_revisions(argv.argc, argv.argv, &rev, NULL);
 514         if (prepare_revision_walk(&rev))
 515                 die("revision walk setup failed");
 516
 517         /*
 518          * Collect all submodules (whether checked out or not) for which new
 519          * commits have been recorded upstream in "changed_submodule_paths".
 520          */
 521         while ((commit = get_revision(&rev))) {
 522                 struct commit_list *parent = commit->parents;
 523                 while (parent) {
 524                         struct diff_options diff_opts;
 525                         diff_setup(&diff_opts);
 526                         DIFF_OPT_SET(&diff_opts, RECURSIVE);
 527                         diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
 528                         diff_opts.format_callback = submodule_collect_changed_cb;
 529                         if (diff_setup_done(&diff_opts) < 0)
 530                                 die("diff_setup_done failed");
 531                         diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
 532                         diffcore_std(&diff_opts);
 533                         diff_flush(&diff_opts);
 534                         parent = parent->next;
 535                 }
 536         }
 537
 538         argv_array_clear(&argv);
 539         sha1_array_clear(&ref_tips_before_fetch);
 540         sha1_array_clear(&ref_tips_after_fetch);
 541         initialized_fetch_ref_tips = 0;
 542 }
 543
 544 int fetch_populated_submodules(int num_options, const char **options,
 545                                const char *prefix, int command_line_option,
 546                                int quiet)
 547 {
 548         int i, result = 0, argc = 0, default_argc;
 549         struct child_process cp;
 550         const char **argv;
 551         struct string_list_item *name_for_path;
 552         const char *work_tree = get_git_work_tree();
 553         if (!work_tree)
 554                 goto out;
 555
 556         if (!the_index.initialized)
 557                 if (read_cache() < 0)
 558                         die("index file corrupt");
 559
 560         /* 6: "fetch" (options) --recurse-submodules-default default "--submodule-prefix" prefix NULL */
 561         argv = xcalloc(num_options + 6, sizeof(const char *));
 562         argv[argc++] = "fetch";
 563         for (i = 0; i < num_options; i++)
 564                 argv[argc++] = options[i];
 565         argv[argc++] = "--recurse-submodules-default";
 566         default_argc = argc++;
 567         argv[argc++] = "--submodule-prefix";
 568
 569         memset(&cp, 0, sizeof(cp));
 570         cp.argv = argv;
 571         cp.env = local_repo_env;
 572         cp.git_cmd = 1;
 573         cp.no_stdin = 1;
 574
 575         calculate_changed_submodule_paths();
 576
 577         for (i = 0; i < active_nr; i++) {
 578                 struct strbuf submodule_path = STRBUF_INIT;
 579                 struct strbuf submodule_git_dir = STRBUF_INIT;
 580                 struct strbuf submodule_prefix = STRBUF_INIT;
 581                 struct cache_entry *ce = active_cache[i];
 582                 const char *git_dir, *name, *default_argv;
 583
 584                 if (!S_ISGITLINK(ce->ce_mode))
 585                         continue;
 586
 587                 name = ce->name;
 588                 name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
 589                 if (name_for_path)
 590                         name = name_for_path->util;
 591
 592                 default_argv = "yes";
 593                 if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
 594                         struct string_list_item *fetch_recurse_submodules_option;
 595                         fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
 596                         if (fetch_recurse_submodules_option) {
 597                                 if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
 598                                         continue;
 599                                 if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
 600                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 601                                                 continue;
 602                                         default_argv = "on-demand";
 603                                 }
 604                         } else {
 605                                 if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
 606                                     gitmodules_is_unmerged)
 607                                         continue;
 608                                 if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
 609                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 610                                                 continue;
 611                                         default_argv = "on-demand";
 612                                 }
 613                         }
 614                 } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
 615                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
 616                                 continue;
 617                         default_argv = "on-demand";
 618                 }
 619
 620                 strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
 621                 strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
 622                 strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
 623                 git_dir = read_gitfile(submodule_git_dir.buf);
 624                 if (!git_dir)
 625                         git_dir = submodule_git_dir.buf;
 626                 if (is_directory(git_dir)) {
 627                         if (!quiet)
 628                                 printf("Fetching submodule %s%s\n", prefix, ce->name);
 629                         cp.dir = submodule_path.buf;
 630                         argv[default_argc] = default_argv;
 631                         argv[argc] = submodule_prefix.buf;
 632                         if (run_command(&cp))
 633                                 result = 1;
 634                 }
 635                 strbuf_release(&submodule_path);
 636                 strbuf_release(&submodule_git_dir);
 637                 strbuf_release(&submodule_prefix);
 638         }
 639         free(argv);
 640 out:
 641         string_list_clear(&changed_submodule_paths, 1);
 642         return result;
 643 }
 644
 645 unsigned is_submodule_modified(const char *path, int ignore_untracked)
 646 {
 647         ssize_t len;
 648         struct child_process cp;
 649         const char *argv[] = {
 650                 "status",
 651                 "--porcelain",
 652                 NULL,
 653                 NULL,
 654         };
 655         struct strbuf buf = STRBUF_INIT;
 656         unsigned dirty_submodule = 0;
 657         const char *line, *next_line;
 658         const char *git_dir;
 659
 660         strbuf_addf(&buf, "%s/.git", path);
 661         git_dir = read_gitfile(buf.buf);
 662         if (!git_dir)
 663                 git_dir = buf.buf;
 664         if (!is_directory(git_dir)) {
 665                 strbuf_release(&buf);
 666                 /* The submodule is not checked out, so it is not modified */
 667                 return 0;
 668
 669         }
 670         strbuf_reset(&buf);
 671
 672         if (ignore_untracked)
 673                 argv[2] = "-uno";
 674
 675         memset(&cp, 0, sizeof(cp));
 676         cp.argv = argv;
 677         cp.env = local_repo_env;
 678         cp.git_cmd = 1;
 679         cp.no_stdin = 1;
 680         cp.out = -1;
 681         cp.dir = path;
 682         if (start_command(&cp))
 683                 die("Could not run 'git status --porcelain' in submodule %s", path);
 684
 685         len = strbuf_read(&buf, cp.out, 1024);
 686         line = buf.buf;
 687         while (len > 2) {
 688                 if ((line[0] == '?') && (line[1] == '?')) {
 689                         dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
 690                         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 691                                 break;
 692                 } else {
 693                         dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
 694                         if (ignore_untracked ||
 695                             (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
 696                                 break;
 697                 }
 698                 next_line = strchr(line, '\n');
 699                 if (!next_line)
 700                         break;
 701                 next_line++;
 702                 len -= (next_line - line);
 703                 line = next_line;
 704         }
 705         close(cp.out);
 706
 707         if (finish_command(&cp))
 708                 die("'git status --porcelain' failed in submodule %s", path);
 709
 710         strbuf_release(&buf);
 711         return dirty_submodule;
 712 }
 713
 714 static int find_first_merges(struct object_array *result, const char *path,
 715                 struct commit *a, struct commit *b)
 716 {
 717         int i, j;
 718         struct object_array merges;
 719         struct commit *commit;
 720         int contains_another;
 721
 722         char merged_revision[42];
 723         const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
 724                                    "--all", merged_revision, NULL };
 725         struct rev_info revs;
 726         struct setup_revision_opt rev_opts;
 727
 728         memset(&merges, 0, sizeof(merges));
 729         memset(result, 0, sizeof(struct object_array));
 730         memset(&rev_opts, 0, sizeof(rev_opts));
 731
 732         /* get all revisions that merge commit a */
 733         snprintf(merged_revision, sizeof(merged_revision), "^%s",
 734                         sha1_to_hex(a->object.sha1));
 735         init_revisions(&revs, NULL);
 736         rev_opts.submodule = path;
 737         setup_revisions(sizeof(rev_args)/sizeof(char *)-1, rev_args, &revs, &rev_opts);
 738
 739         /* save all revisions from the above list that contain b */
 740         if (prepare_revision_walk(&revs))
 741                 die("revision walk setup failed");
 742         while ((commit = get_revision(&revs)) != NULL) {
 743                 struct object *o = &(commit->object);
 744                 if (in_merge_bases(b, &commit, 1))
 745                         add_object_array(o, NULL, &merges);
 746         }
 747
 748         /* Now we've got all merges that contain a and b. Prune all
 749          * merges that contain another found merge and save them in
 750          * result.
 751          */
 752         for (i = 0; i < merges.nr; i++) {
 753                 struct commit *m1 = (struct commit *) merges.objects[i].item;
 754
 755                 contains_another = 0;
 756                 for (j = 0; j < merges.nr; j++) {
 757                         struct commit *m2 = (struct commit *) merges.objects[j].item;
 758                         if (i != j && in_merge_bases(m2, &m1, 1)) {
 759                                 contains_another = 1;
 760                                 break;
 761                         }
 762                 }
 763
 764                 if (!contains_another)
 765                         add_object_array(merges.objects[i].item,
 766                                          merges.objects[i].name, result);
 767         }
 768
 769         free(merges.objects);
 770         return result->nr;
 771 }
 772
 773 static void print_commit(struct commit *commit)
 774 {
 775         struct strbuf sb = STRBUF_INIT;
 776         struct pretty_print_context ctx = {0};
 777         ctx.date_mode = DATE_NORMAL;
 778         format_commit_message(commit, " %h: %m %s", &sb, &ctx);
 779         fprintf(stderr, "%s\n", sb.buf);
 780         strbuf_release(&sb);
 781 }
 782
 783 #define MERGE_WARNING(path, msg) \
 784         warning("Failed to merge submodule %s (%s)", path, msg);
 785
 786 int merge_submodule(unsigned char result[20], const char *path,
 787                     const unsigned char base[20], const unsigned char a[20],
 788                     const unsigned char b[20], int search)
 789 {
 790         struct commit *commit_base, *commit_a, *commit_b;
 791         int parent_count;
 792         struct object_array merges;
 793
 794         int i;
 795
 796         /* store a in result in case we fail */
 797         hashcpy(result, a);
 798
 799         /* we can not handle deletion conflicts */
 800         if (is_null_sha1(base))
 801                 return 0;
 802         if (is_null_sha1(a))
 803                 return 0;
 804         if (is_null_sha1(b))
 805                 return 0;
 806
 807         if (add_submodule_odb(path)) {
 808                 MERGE_WARNING(path, "not checked out");
 809                 return 0;
 810         }
 811
 812         if (!(commit_base = lookup_commit_reference(base)) ||
 813             !(commit_a = lookup_commit_reference(a)) ||
 814             !(commit_b = lookup_commit_reference(b))) {
 815                 MERGE_WARNING(path, "commits not present");
 816                 return 0;
 817         }
 818
 819         /* check whether both changes are forward */
 820         if (!in_merge_bases(commit_base, &commit_a, 1) ||
 821             !in_merge_bases(commit_base, &commit_b, 1)) {
 822                 MERGE_WARNING(path, "commits don't follow merge-base");
 823                 return 0;
 824         }
 825
 826         /* Case #1: a is contained in b or vice versa */
 827         if (in_merge_bases(commit_a, &commit_b, 1)) {
 828                 hashcpy(result, b);
 829                 return 1;
 830         }
 831         if (in_merge_bases(commit_b, &commit_a, 1)) {
 832                 hashcpy(result, a);
 833                 return 1;
 834         }
 835
 836         /*
 837          * Case #2: There are one or more merges that contain a and b in
 838          * the submodule. If there is only one, then present it as a
 839          * suggestion to the user, but leave it marked unmerged so the
 840          * user needs to confirm the resolution.
 841          */
 842
 843         /* Skip the search if makes no sense to the calling context.  */
 844         if (!search)
 845                 return 0;
 846
 847         /* find commit which merges them */
 848         parent_count = find_first_merges(&merges, path, commit_a, commit_b);
 849         switch (parent_count) {
 850         case 0:
 851                 MERGE_WARNING(path, "merge following commits not found");
 852                 break;
 853
 854         case 1:
 855                 MERGE_WARNING(path, "not fast-forward");
 856                 fprintf(stderr, "Found a possible merge resolution "
 857                                 "for the submodule:\n");
 858                 print_commit((struct commit *) merges.objects[0].item);
 859                 fprintf(stderr,
 860                         "If this is correct simply add it to the index "
 861                         "for example\n"
 862                         "by using:\n\n"
 863                         "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
 864                         "which will accept this suggestion.\n",
 865                         sha1_to_hex(merges.objects[0].item->sha1), path);
 866                 break;
 867
 868         default:
 869                 MERGE_WARNING(path, "multiple merges found");
 870                 for (i = 0; i < merges.nr; i++)
 871                         print_commit((struct commit *) merges.objects[i].item);
 872         }
 873
 874         free(merges.objects);
 875         return 0;
 876 }