git.oblomov.eu Git - git/blob - submodule.c

   1 #include "cache.h"
   2 #include "repository.h"
   3 #include "config.h"
   4 #include "submodule-config.h"
   5 #include "submodule.h"
   6 #include "dir.h"
   7 #include "diff.h"
   8 #include "commit.h"
   9 #include "revision.h"
  10 #include "run-command.h"
  11 #include "diffcore.h"
  12 #include "refs.h"
  13 #include "string-list.h"
  14 #include "sha1-array.h"
  15 #include "argv-array.h"
  16 #include "blob.h"
  17 #include "thread-utils.h"
  18 #include "quote.h"
  19 #include "remote.h"
  20 #include "worktree.h"
  21 #include "parse-options.h"
  22
  23 static int config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
  24 static struct string_list changed_submodule_paths = STRING_LIST_INIT_DUP;
  25 static int initialized_fetch_ref_tips;
  26 static struct oid_array ref_tips_before_fetch;
  27 static struct oid_array ref_tips_after_fetch;
  28
  29 /*
  30  * Check if the .gitmodules file is unmerged. Parsing of the .gitmodules file
  31  * will be disabled because we can't guess what might be configured in
  32  * .gitmodules unless the user resolves the conflict.
  33  */
  34 int is_gitmodules_unmerged(const struct index_state *istate)
  35 {
  36         int pos = index_name_pos(istate, GITMODULES_FILE, strlen(GITMODULES_FILE));
  37         if (pos < 0) { /* .gitmodules not found or isn't merged */
  38                 pos = -1 - pos;
  39                 if (istate->cache_nr > pos) {  /* there is a .gitmodules */
  40                         const struct cache_entry *ce = istate->cache[pos];
  41                         if (ce_namelen(ce) == strlen(GITMODULES_FILE) &&
  42                             !strcmp(ce->name, GITMODULES_FILE))
  43                                 return 1;
  44                 }
  45         }
  46
  47         return 0;
  48 }
  49
  50 /*
  51  * Check if the .gitmodules file has unstaged modifications.  This must be
  52  * checked before allowing modifications to the .gitmodules file with the
  53  * intention to stage them later, because when continuing we would stage the
  54  * modifications the user didn't stage herself too. That might change in a
  55  * future version when we learn to stage the changes we do ourselves without
  56  * staging any previous modifications.
  57  */
  58 int is_staging_gitmodules_ok(const struct index_state *istate)
  59 {
  60         int pos = index_name_pos(istate, GITMODULES_FILE, strlen(GITMODULES_FILE));
  61
  62         if ((pos >= 0) && (pos < istate->cache_nr)) {
  63                 struct stat st;
  64                 if (lstat(GITMODULES_FILE, &st) == 0 &&
  65                     ce_match_stat(istate->cache[pos], &st, 0) & DATA_CHANGED)
  66                         return 0;
  67         }
  68
  69         return 1;
  70 }
  71
  72 static int for_each_remote_ref_submodule(const char *submodule,
  73                                          each_ref_fn fn, void *cb_data)
  74 {
  75         return refs_for_each_remote_ref(get_submodule_ref_store(submodule),
  76                                         fn, cb_data);
  77 }
  78
  79 /*
  80  * Try to update the "path" entry in the "submodule.<name>" section of the
  81  * .gitmodules file. Return 0 only if a .gitmodules file was found, a section
  82  * with the correct path=<oldpath> setting was found and we could update it.
  83  */
  84 int update_path_in_gitmodules(const char *oldpath, const char *newpath)
  85 {
  86         struct strbuf entry = STRBUF_INIT;
  87         const struct submodule *submodule;
  88
  89         if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
  90                 return -1;
  91
  92         if (is_gitmodules_unmerged(&the_index))
  93                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
  94
  95         submodule = submodule_from_path(&null_oid, oldpath);
  96         if (!submodule || !submodule->name) {
  97                 warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
  98                 return -1;
  99         }
 100         strbuf_addstr(&entry, "submodule.");
 101         strbuf_addstr(&entry, submodule->name);
 102         strbuf_addstr(&entry, ".path");
 103         if (git_config_set_in_file_gently(GITMODULES_FILE, entry.buf, newpath) < 0) {
 104                 /* Maybe the user already did that, don't error out here */
 105                 warning(_("Could not update .gitmodules entry %s"), entry.buf);
 106                 strbuf_release(&entry);
 107                 return -1;
 108         }
 109         strbuf_release(&entry);
 110         return 0;
 111 }
 112
 113 /*
 114  * Try to remove the "submodule.<name>" section from .gitmodules where the given
 115  * path is configured. Return 0 only if a .gitmodules file was found, a section
 116  * with the correct path=<path> setting was found and we could remove it.
 117  */
 118 int remove_path_from_gitmodules(const char *path)
 119 {
 120         struct strbuf sect = STRBUF_INIT;
 121         const struct submodule *submodule;
 122
 123         if (!file_exists(GITMODULES_FILE)) /* Do nothing without .gitmodules */
 124                 return -1;
 125
 126         if (is_gitmodules_unmerged(&the_index))
 127                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 128
 129         submodule = submodule_from_path(&null_oid, path);
 130         if (!submodule || !submodule->name) {
 131                 warning(_("Could not find section in .gitmodules where path=%s"), path);
 132                 return -1;
 133         }
 134         strbuf_addstr(&sect, "submodule.");
 135         strbuf_addstr(&sect, submodule->name);
 136         if (git_config_rename_section_in_file(GITMODULES_FILE, sect.buf, NULL) < 0) {
 137                 /* Maybe the user already did that, don't error out here */
 138                 warning(_("Could not remove .gitmodules entry for %s"), path);
 139                 strbuf_release(&sect);
 140                 return -1;
 141         }
 142         strbuf_release(&sect);
 143         return 0;
 144 }
 145
 146 void stage_updated_gitmodules(void)
 147 {
 148         if (add_file_to_cache(GITMODULES_FILE, 0))
 149                 die(_("staging updated .gitmodules failed"));
 150 }
 151
 152 static int add_submodule_odb(const char *path)
 153 {
 154         struct strbuf objects_directory = STRBUF_INIT;
 155         int ret = 0;
 156
 157         ret = strbuf_git_path_submodule(&objects_directory, path, "objects/");
 158         if (ret)
 159                 goto done;
 160         if (!is_directory(objects_directory.buf)) {
 161                 ret = -1;
 162                 goto done;
 163         }
 164         add_to_alternates_memory(objects_directory.buf);
 165 done:
 166         strbuf_release(&objects_directory);
 167         return ret;
 168 }
 169
 170 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 171                                              const char *path)
 172 {
 173         const struct submodule *submodule = submodule_from_path(&null_oid, path);
 174         if (submodule) {
 175                 const char *ignore;
 176                 char *key;
 177
 178                 key = xstrfmt("submodule.%s.ignore", submodule->name);
 179                 if (repo_config_get_string_const(the_repository, key, &ignore))
 180                         ignore = submodule->ignore;
 181                 free(key);
 182
 183                 if (ignore)
 184                         handle_ignore_submodules_arg(diffopt, ignore);
 185                 else if (is_gitmodules_unmerged(&the_index))
 186                         DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 187         }
 188 }
 189
 190 /* Cheap function that only determines if we're interested in submodules at all */
 191 int git_default_submodule_config(const char *var, const char *value, void *cb)
 192 {
 193         if (!strcmp(var, "submodule.recurse")) {
 194                 int v = git_config_bool(var, value) ?
 195                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 196                 config_update_recurse_submodules = v;
 197         }
 198         return 0;
 199 }
 200
 201 int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
 202                                                      const char *arg, int unset)
 203 {
 204         if (unset) {
 205                 config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
 206                 return 0;
 207         }
 208         if (arg)
 209                 config_update_recurse_submodules =
 210                         parse_update_recurse_submodules_arg(opt->long_name,
 211                                                             arg);
 212         else
 213                 config_update_recurse_submodules = RECURSE_SUBMODULES_ON;
 214
 215         return 0;
 216 }
 217
 218 /*
 219  * Determine if a submodule has been initialized at a given 'path'
 220  */
 221 int is_submodule_active(struct repository *repo, const char *path)
 222 {
 223         int ret = 0;
 224         char *key = NULL;
 225         char *value = NULL;
 226         const struct string_list *sl;
 227         const struct submodule *module;
 228
 229         module = submodule_from_cache(repo, &null_oid, path);
 230
 231         /* early return if there isn't a path->module mapping */
 232         if (!module)
 233                 return 0;
 234
 235         /* submodule.<name>.active is set */
 236         key = xstrfmt("submodule.%s.active", module->name);
 237         if (!repo_config_get_bool(repo, key, &ret)) {
 238                 free(key);
 239                 return ret;
 240         }
 241         free(key);
 242
 243         /* submodule.active is set */
 244         sl = repo_config_get_value_multi(repo, "submodule.active");
 245         if (sl) {
 246                 struct pathspec ps;
 247                 struct argv_array args = ARGV_ARRAY_INIT;
 248                 const struct string_list_item *item;
 249
 250                 for_each_string_list_item(item, sl) {
 251                         argv_array_push(&args, item->string);
 252                 }
 253
 254                 parse_pathspec(&ps, 0, 0, NULL, args.argv);
 255                 ret = match_pathspec(&ps, path, strlen(path), 0, NULL, 1);
 256
 257                 argv_array_clear(&args);
 258                 clear_pathspec(&ps);
 259                 return ret;
 260         }
 261
 262         /* fallback to checking if the URL is set */
 263         key = xstrfmt("submodule.%s.url", module->name);
 264         ret = !repo_config_get_string(repo, key, &value);
 265
 266         free(value);
 267         free(key);
 268         return ret;
 269 }
 270
 271 int is_submodule_populated_gently(const char *path, int *return_error_code)
 272 {
 273         int ret = 0;
 274         char *gitdir = xstrfmt("%s/.git", path);
 275
 276         if (resolve_gitdir_gently(gitdir, return_error_code))
 277                 ret = 1;
 278
 279         free(gitdir);
 280         return ret;
 281 }
 282
 283 /*
 284  * Dies if the provided 'prefix' corresponds to an unpopulated submodule
 285  */
 286 void die_in_unpopulated_submodule(const struct index_state *istate,
 287                                   const char *prefix)
 288 {
 289         int i, prefixlen;
 290
 291         if (!prefix)
 292                 return;
 293
 294         prefixlen = strlen(prefix);
 295
 296         for (i = 0; i < istate->cache_nr; i++) {
 297                 struct cache_entry *ce = istate->cache[i];
 298                 int ce_len = ce_namelen(ce);
 299
 300                 if (!S_ISGITLINK(ce->ce_mode))
 301                         continue;
 302                 if (prefixlen <= ce_len)
 303                         continue;
 304                 if (strncmp(ce->name, prefix, ce_len))
 305                         continue;
 306                 if (prefix[ce_len] != '/')
 307                         continue;
 308
 309                 die(_("in unpopulated submodule '%s'"), ce->name);
 310         }
 311 }
 312
 313 /*
 314  * Dies if any paths in the provided pathspec descends into a submodule
 315  */
 316 void die_path_inside_submodule(const struct index_state *istate,
 317                                const struct pathspec *ps)
 318 {
 319         int i, j;
 320
 321         for (i = 0; i < istate->cache_nr; i++) {
 322                 struct cache_entry *ce = istate->cache[i];
 323                 int ce_len = ce_namelen(ce);
 324
 325                 if (!S_ISGITLINK(ce->ce_mode))
 326                         continue;
 327
 328                 for (j = 0; j < ps->nr ; j++) {
 329                         const struct pathspec_item *item = &ps->items[j];
 330
 331                         if (item->len <= ce_len)
 332                                 continue;
 333                         if (item->match[ce_len] != '/')
 334                                 continue;
 335                         if (strncmp(ce->name, item->match, ce_len))
 336                                 continue;
 337                         if (item->len == ce_len + 1)
 338                                 continue;
 339
 340                         die(_("Pathspec '%s' is in submodule '%.*s'"),
 341                             item->original, ce_len, ce->name);
 342                 }
 343         }
 344 }
 345
 346 enum submodule_update_type parse_submodule_update_type(const char *value)
 347 {
 348         if (!strcmp(value, "none"))
 349                 return SM_UPDATE_NONE;
 350         else if (!strcmp(value, "checkout"))
 351                 return SM_UPDATE_CHECKOUT;
 352         else if (!strcmp(value, "rebase"))
 353                 return SM_UPDATE_REBASE;
 354         else if (!strcmp(value, "merge"))
 355                 return SM_UPDATE_MERGE;
 356         else if (*value == '!')
 357                 return SM_UPDATE_COMMAND;
 358         else
 359                 return SM_UPDATE_UNSPECIFIED;
 360 }
 361
 362 int parse_submodule_update_strategy(const char *value,
 363                 struct submodule_update_strategy *dst)
 364 {
 365         enum submodule_update_type type;
 366
 367         free((void*)dst->command);
 368         dst->command = NULL;
 369
 370         type = parse_submodule_update_type(value);
 371         if (type == SM_UPDATE_UNSPECIFIED)
 372                 return -1;
 373
 374         dst->type = type;
 375         if (type == SM_UPDATE_COMMAND)
 376                 dst->command = xstrdup(value + 1);
 377
 378         return 0;
 379 }
 380
 381 const char *submodule_strategy_to_string(const struct submodule_update_strategy *s)
 382 {
 383         struct strbuf sb = STRBUF_INIT;
 384         switch (s->type) {
 385         case SM_UPDATE_CHECKOUT:
 386                 return "checkout";
 387         case SM_UPDATE_MERGE:
 388                 return "merge";
 389         case SM_UPDATE_REBASE:
 390                 return "rebase";
 391         case SM_UPDATE_NONE:
 392                 return "none";
 393         case SM_UPDATE_UNSPECIFIED:
 394                 return NULL;
 395         case SM_UPDATE_COMMAND:
 396                 strbuf_addf(&sb, "!%s", s->command);
 397                 return strbuf_detach(&sb, NULL);
 398         }
 399         return NULL;
 400 }
 401
 402 void handle_ignore_submodules_arg(struct diff_options *diffopt,
 403                                   const char *arg)
 404 {
 405         DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
 406         DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 407         DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
 408
 409         if (!strcmp(arg, "all"))
 410                 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 411         else if (!strcmp(arg, "untracked"))
 412                 DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 413         else if (!strcmp(arg, "dirty"))
 414                 DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
 415         else if (strcmp(arg, "none"))
 416                 die("bad --ignore-submodules argument: %s", arg);
 417 }
 418
 419 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 420                 struct commit *left, struct commit *right,
 421                 struct commit_list *merge_bases)
 422 {
 423         struct commit_list *list;
 424
 425         init_revisions(rev, NULL);
 426         setup_revisions(0, NULL, rev, NULL);
 427         rev->left_right = 1;
 428         rev->first_parent_only = 1;
 429         left->object.flags |= SYMMETRIC_LEFT;
 430         add_pending_object(rev, &left->object, path);
 431         add_pending_object(rev, &right->object, path);
 432         for (list = merge_bases; list; list = list->next) {
 433                 list->item->object.flags |= UNINTERESTING;
 434                 add_pending_object(rev, &list->item->object,
 435                         oid_to_hex(&list->item->object.oid));
 436         }
 437         return prepare_revision_walk(rev);
 438 }
 439
 440 static void print_submodule_summary(struct rev_info *rev, struct diff_options *o)
 441 {
 442         static const char format[] = "  %m %s";
 443         struct strbuf sb = STRBUF_INIT;
 444         struct commit *commit;
 445
 446         while ((commit = get_revision(rev))) {
 447                 struct pretty_print_context ctx = {0};
 448                 ctx.date_mode = rev->date_mode;
 449                 ctx.output_encoding = get_log_output_encoding();
 450                 strbuf_setlen(&sb, 0);
 451                 format_commit_message(commit, format, &sb, &ctx);
 452                 strbuf_addch(&sb, '\n');
 453                 if (commit->object.flags & SYMMETRIC_LEFT)
 454                         diff_emit_submodule_del(o, sb.buf);
 455                 else
 456                         diff_emit_submodule_add(o, sb.buf);
 457         }
 458         strbuf_release(&sb);
 459 }
 460
 461 static void prepare_submodule_repo_env_no_git_dir(struct argv_array *out)
 462 {
 463         const char * const *var;
 464
 465         for (var = local_repo_env; *var; var++) {
 466                 if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
 467                         argv_array_push(out, *var);
 468         }
 469 }
 470
 471 void prepare_submodule_repo_env(struct argv_array *out)
 472 {
 473         prepare_submodule_repo_env_no_git_dir(out);
 474         argv_array_pushf(out, "%s=%s", GIT_DIR_ENVIRONMENT,
 475                          DEFAULT_GIT_DIR_ENVIRONMENT);
 476 }
 477
 478 /* Helper function to display the submodule header line prior to the full
 479  * summary output. If it can locate the submodule objects directory it will
 480  * attempt to lookup both the left and right commits and put them into the
 481  * left and right pointers.
 482  */
 483 static void show_submodule_header(struct diff_options *o, const char *path,
 484                 struct object_id *one, struct object_id *two,
 485                 unsigned dirty_submodule,
 486                 struct commit **left, struct commit **right,
 487                 struct commit_list **merge_bases)
 488 {
 489         const char *message = NULL;
 490         struct strbuf sb = STRBUF_INIT;
 491         int fast_forward = 0, fast_backward = 0;
 492
 493         if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
 494                 diff_emit_submodule_untracked(o, path);
 495
 496         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 497                 diff_emit_submodule_modified(o, path);
 498
 499         if (is_null_oid(one))
 500                 message = "(new submodule)";
 501         else if (is_null_oid(two))
 502                 message = "(submodule deleted)";
 503
 504         if (add_submodule_odb(path)) {
 505                 if (!message)
 506                         message = "(not initialized)";
 507                 goto output_header;
 508         }
 509
 510         /*
 511          * Attempt to lookup the commit references, and determine if this is
 512          * a fast forward or fast backwards update.
 513          */
 514         *left = lookup_commit_reference(one);
 515         *right = lookup_commit_reference(two);
 516
 517         /*
 518          * Warn about missing commits in the submodule project, but only if
 519          * they aren't null.
 520          */
 521         if ((!is_null_oid(one) && !*left) ||
 522              (!is_null_oid(two) && !*right))
 523                 message = "(commits not present)";
 524
 525         *merge_bases = get_merge_bases(*left, *right);
 526         if (*merge_bases) {
 527                 if ((*merge_bases)->item == *left)
 528                         fast_forward = 1;
 529                 else if ((*merge_bases)->item == *right)
 530                         fast_backward = 1;
 531         }
 532
 533         if (!oidcmp(one, two)) {
 534                 strbuf_release(&sb);
 535                 return;
 536         }
 537
 538 output_header:
 539         strbuf_addf(&sb, "Submodule %s ", path);
 540         strbuf_add_unique_abbrev(&sb, one->hash, DEFAULT_ABBREV);
 541         strbuf_addstr(&sb, (fast_backward || fast_forward) ? ".." : "...");
 542         strbuf_add_unique_abbrev(&sb, two->hash, DEFAULT_ABBREV);
 543         if (message)
 544                 strbuf_addf(&sb, " %s\n", message);
 545         else
 546                 strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
 547         diff_emit_submodule_header(o, sb.buf);
 548
 549         strbuf_release(&sb);
 550 }
 551
 552 void show_submodule_summary(struct diff_options *o, const char *path,
 553                 struct object_id *one, struct object_id *two,
 554                 unsigned dirty_submodule)
 555 {
 556         struct rev_info rev;
 557         struct commit *left = NULL, *right = NULL;
 558         struct commit_list *merge_bases = NULL;
 559
 560         show_submodule_header(o, path, one, two, dirty_submodule,
 561                               &left, &right, &merge_bases);
 562
 563         /*
 564          * If we don't have both a left and a right pointer, there is no
 565          * reason to try and display a summary. The header line should contain
 566          * all the information the user needs.
 567          */
 568         if (!left || !right)
 569                 goto out;
 570
 571         /* Treat revision walker failure the same as missing commits */
 572         if (prepare_submodule_summary(&rev, path, left, right, merge_bases)) {
 573                 diff_emit_submodule_error(o, "(revision walker failed)\n");
 574                 goto out;
 575         }
 576
 577         print_submodule_summary(&rev, o);
 578
 579 out:
 580         if (merge_bases)
 581                 free_commit_list(merge_bases);
 582         clear_commit_marks(left, ~0);
 583         clear_commit_marks(right, ~0);
 584 }
 585
 586 void show_submodule_inline_diff(struct diff_options *o, const char *path,
 587                 struct object_id *one, struct object_id *two,
 588                 unsigned dirty_submodule)
 589 {
 590         const struct object_id *old = &empty_tree_oid, *new = &empty_tree_oid;
 591         struct commit *left = NULL, *right = NULL;
 592         struct commit_list *merge_bases = NULL;
 593         struct child_process cp = CHILD_PROCESS_INIT;
 594         struct strbuf sb = STRBUF_INIT;
 595
 596         show_submodule_header(o, path, one, two, dirty_submodule,
 597                               &left, &right, &merge_bases);
 598
 599         /* We need a valid left and right commit to display a difference */
 600         if (!(left || is_null_oid(one)) ||
 601             !(right || is_null_oid(two)))
 602                 goto done;
 603
 604         if (left)
 605                 old = one;
 606         if (right)
 607                 new = two;
 608
 609         cp.git_cmd = 1;
 610         cp.dir = path;
 611         cp.out = -1;
 612         cp.no_stdin = 1;
 613
 614         /* TODO: other options may need to be passed here. */
 615         argv_array_pushl(&cp.args, "diff", "--submodule=diff", NULL);
 616         argv_array_pushf(&cp.args, "--color=%s", want_color(o->use_color) ?
 617                          "always" : "never");
 618
 619         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 620                 argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 621                                  o->b_prefix, path);
 622                 argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
 623                                  o->a_prefix, path);
 624         } else {
 625                 argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 626                                  o->a_prefix, path);
 627                 argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
 628                                  o->b_prefix, path);
 629         }
 630         argv_array_push(&cp.args, oid_to_hex(old));
 631         /*
 632          * If the submodule has modified content, we will diff against the
 633          * work tree, under the assumption that the user has asked for the
 634          * diff format and wishes to actually see all differences even if they
 635          * haven't yet been committed to the submodule yet.
 636          */
 637         if (!(dirty_submodule & DIRTY_SUBMODULE_MODIFIED))
 638                 argv_array_push(&cp.args, oid_to_hex(new));
 639
 640         prepare_submodule_repo_env(&cp.env_array);
 641         if (start_command(&cp))
 642                 diff_emit_submodule_error(o, "(diff failed)\n");
 643
 644         while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
 645                 diff_emit_submodule_pipethrough(o, sb.buf, sb.len);
 646
 647         if (finish_command(&cp))
 648                 diff_emit_submodule_error(o, "(diff failed)\n");
 649
 650 done:
 651         strbuf_release(&sb);
 652         if (merge_bases)
 653                 free_commit_list(merge_bases);
 654         if (left)
 655                 clear_commit_marks(left, ~0);
 656         if (right)
 657                 clear_commit_marks(right, ~0);
 658 }
 659
 660 int should_update_submodules(void)
 661 {
 662         return config_update_recurse_submodules == RECURSE_SUBMODULES_ON;
 663 }
 664
 665 const struct submodule *submodule_from_ce(const struct cache_entry *ce)
 666 {
 667         if (!S_ISGITLINK(ce->ce_mode))
 668                 return NULL;
 669
 670         if (!should_update_submodules())
 671                 return NULL;
 672
 673         return submodule_from_path(&null_oid, ce->name);
 674 }
 675
 676 static struct oid_array *submodule_commits(struct string_list *submodules,
 677                                            const char *path)
 678 {
 679         struct string_list_item *item;
 680
 681         item = string_list_insert(submodules, path);
 682         if (item->util)
 683                 return (struct oid_array *) item->util;
 684
 685         /* NEEDSWORK: should we have oid_array_init()? */
 686         item->util = xcalloc(1, sizeof(struct oid_array));
 687         return (struct oid_array *) item->util;
 688 }
 689
 690 static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 691                                           struct diff_options *options,
 692                                           void *data)
 693 {
 694         int i;
 695         struct string_list *changed = data;
 696
 697         for (i = 0; i < q->nr; i++) {
 698                 struct diff_filepair *p = q->queue[i];
 699                 struct oid_array *commits;
 700                 if (!S_ISGITLINK(p->two->mode))
 701                         continue;
 702
 703                 if (S_ISGITLINK(p->one->mode)) {
 704                         /*
 705                          * NEEDSWORK: We should honor the name configured in
 706                          * the .gitmodules file of the commit we are examining
 707                          * here to be able to correctly follow submodules
 708                          * being moved around.
 709                          */
 710                         commits = submodule_commits(changed, p->two->path);
 711                         oid_array_append(commits, &p->two->oid);
 712                 } else {
 713                         /* Submodule is new or was moved here */
 714                         /*
 715                          * NEEDSWORK: When the .git directories of submodules
 716                          * live inside the superprojects .git directory some
 717                          * day we should fetch new submodules directly into
 718                          * that location too when config or options request
 719                          * that so they can be checked out from there.
 720                          */
 721                         continue;
 722                 }
 723         }
 724 }
 725
 726 /*
 727  * Collect the paths of submodules in 'changed' which have changed based on
 728  * the revisions as specified in 'argv'.  Each entry in 'changed' will also
 729  * have a corresponding 'struct oid_array' (in the 'util' field) which lists
 730  * what the submodule pointers were updated to during the change.
 731  */
 732 static void collect_changed_submodules(struct string_list *changed,
 733                                        struct argv_array *argv)
 734 {
 735         struct rev_info rev;
 736         const struct commit *commit;
 737
 738         init_revisions(&rev, NULL);
 739         setup_revisions(argv->argc, argv->argv, &rev, NULL);
 740         if (prepare_revision_walk(&rev))
 741                 die("revision walk setup failed");
 742
 743         while ((commit = get_revision(&rev))) {
 744                 struct rev_info diff_rev;
 745
 746                 init_revisions(&diff_rev, NULL);
 747                 diff_rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 748                 diff_rev.diffopt.format_callback = collect_changed_submodules_cb;
 749                 diff_rev.diffopt.format_callback_data = changed;
 750                 diff_tree_combined_merge(commit, 1, &diff_rev);
 751         }
 752
 753         reset_revision_walk();
 754 }
 755
 756 static void free_submodules_oids(struct string_list *submodules)
 757 {
 758         struct string_list_item *item;
 759         for_each_string_list_item(item, submodules)
 760                 oid_array_clear((struct oid_array *) item->util);
 761         string_list_clear(submodules, 1);
 762 }
 763
 764 static int has_remote(const char *refname, const struct object_id *oid,
 765                       int flags, void *cb_data)
 766 {
 767         return 1;
 768 }
 769
 770 static int append_oid_to_argv(const struct object_id *oid, void *data)
 771 {
 772         struct argv_array *argv = data;
 773         argv_array_push(argv, oid_to_hex(oid));
 774         return 0;
 775 }
 776
 777 static int check_has_commit(const struct object_id *oid, void *data)
 778 {
 779         int *has_commit = data;
 780
 781         if (!lookup_commit_reference(oid))
 782                 *has_commit = 0;
 783
 784         return 0;
 785 }
 786
 787 static int submodule_has_commits(const char *path, struct oid_array *commits)
 788 {
 789         int has_commit = 1;
 790
 791         /*
 792          * Perform a cheap, but incorrect check for the existence of 'commits'.
 793          * This is done by adding the submodule's object store to the in-core
 794          * object store, and then querying for each commit's existence.  If we
 795          * do not have the commit object anywhere, there is no chance we have
 796          * it in the object store of the correct submodule and have it
 797          * reachable from a ref, so we can fail early without spawning rev-list
 798          * which is expensive.
 799          */
 800         if (add_submodule_odb(path))
 801                 return 0;
 802
 803         oid_array_for_each_unique(commits, check_has_commit, &has_commit);
 804
 805         if (has_commit) {
 806                 /*
 807                  * Even if the submodule is checked out and the commit is
 808                  * present, make sure it exists in the submodule's object store
 809                  * and that it is reachable from a ref.
 810                  */
 811                 struct child_process cp = CHILD_PROCESS_INIT;
 812                 struct strbuf out = STRBUF_INIT;
 813
 814                 argv_array_pushl(&cp.args, "rev-list", "-n", "1", NULL);
 815                 oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
 816                 argv_array_pushl(&cp.args, "--not", "--all", NULL);
 817
 818                 prepare_submodule_repo_env(&cp.env_array);
 819                 cp.git_cmd = 1;
 820                 cp.no_stdin = 1;
 821                 cp.dir = path;
 822
 823                 if (capture_command(&cp, &out, GIT_MAX_HEXSZ + 1) || out.len)
 824                         has_commit = 0;
 825
 826                 strbuf_release(&out);
 827         }
 828
 829         return has_commit;
 830 }
 831
 832 static int submodule_needs_pushing(const char *path, struct oid_array *commits)
 833 {
 834         if (!submodule_has_commits(path, commits))
 835                 /*
 836                  * NOTE: We do consider it safe to return "no" here. The
 837                  * correct answer would be "We do not know" instead of
 838                  * "No push needed", but it is quite hard to change
 839                  * the submodule pointer without having the submodule
 840                  * around. If a user did however change the submodules
 841                  * without having the submodule around, this indicates
 842                  * an expert who knows what they are doing or a
 843                  * maintainer integrating work from other people. In
 844                  * both cases it should be safe to skip this check.
 845                  */
 846                 return 0;
 847
 848         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 849                 struct child_process cp = CHILD_PROCESS_INIT;
 850                 struct strbuf buf = STRBUF_INIT;
 851                 int needs_pushing = 0;
 852
 853                 argv_array_push(&cp.args, "rev-list");
 854                 oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
 855                 argv_array_pushl(&cp.args, "--not", "--remotes", "-n", "1" , NULL);
 856
 857                 prepare_submodule_repo_env(&cp.env_array);
 858                 cp.git_cmd = 1;
 859                 cp.no_stdin = 1;
 860                 cp.out = -1;
 861                 cp.dir = path;
 862                 if (start_command(&cp))
 863                         die("Could not run 'git rev-list <commits> --not --remotes -n 1' command in submodule %s",
 864                                         path);
 865                 if (strbuf_read(&buf, cp.out, 41))
 866                         needs_pushing = 1;
 867                 finish_command(&cp);
 868                 close(cp.out);
 869                 strbuf_release(&buf);
 870                 return needs_pushing;
 871         }
 872
 873         return 0;
 874 }
 875
 876 int find_unpushed_submodules(struct oid_array *commits,
 877                 const char *remotes_name, struct string_list *needs_pushing)
 878 {
 879         struct string_list submodules = STRING_LIST_INIT_DUP;
 880         struct string_list_item *submodule;
 881         struct argv_array argv = ARGV_ARRAY_INIT;
 882
 883         /* argv.argv[0] will be ignored by setup_revisions */
 884         argv_array_push(&argv, "find_unpushed_submodules");
 885         oid_array_for_each_unique(commits, append_oid_to_argv, &argv);
 886         argv_array_push(&argv, "--not");
 887         argv_array_pushf(&argv, "--remotes=%s", remotes_name);
 888
 889         collect_changed_submodules(&submodules, &argv);
 890
 891         for_each_string_list_item(submodule, &submodules) {
 892                 struct oid_array *commits = submodule->util;
 893                 const char *path = submodule->string;
 894
 895                 if (submodule_needs_pushing(path, commits))
 896                         string_list_insert(needs_pushing, path);
 897         }
 898
 899         free_submodules_oids(&submodules);
 900         argv_array_clear(&argv);
 901
 902         return needs_pushing->nr;
 903 }
 904
 905 static int push_submodule(const char *path,
 906                           const struct remote *remote,
 907                           const char **refspec, int refspec_nr,
 908                           const struct string_list *push_options,
 909                           int dry_run)
 910 {
 911         if (add_submodule_odb(path))
 912                 return 1;
 913
 914         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 915                 struct child_process cp = CHILD_PROCESS_INIT;
 916                 argv_array_push(&cp.args, "push");
 917                 if (dry_run)
 918                         argv_array_push(&cp.args, "--dry-run");
 919
 920                 if (push_options && push_options->nr) {
 921                         const struct string_list_item *item;
 922                         for_each_string_list_item(item, push_options)
 923                                 argv_array_pushf(&cp.args, "--push-option=%s",
 924                                                  item->string);
 925                 }
 926
 927                 if (remote->origin != REMOTE_UNCONFIGURED) {
 928                         int i;
 929                         argv_array_push(&cp.args, remote->name);
 930                         for (i = 0; i < refspec_nr; i++)
 931                                 argv_array_push(&cp.args, refspec[i]);
 932                 }
 933
 934                 prepare_submodule_repo_env(&cp.env_array);
 935                 cp.git_cmd = 1;
 936                 cp.no_stdin = 1;
 937                 cp.dir = path;
 938                 if (run_command(&cp))
 939                         return 0;
 940                 close(cp.out);
 941         }
 942
 943         return 1;
 944 }
 945
 946 /*
 947  * Perform a check in the submodule to see if the remote and refspec work.
 948  * Die if the submodule can't be pushed.
 949  */
 950 static void submodule_push_check(const char *path, const char *head,
 951                                  const struct remote *remote,
 952                                  const char **refspec, int refspec_nr)
 953 {
 954         struct child_process cp = CHILD_PROCESS_INIT;
 955         int i;
 956
 957         argv_array_push(&cp.args, "submodule--helper");
 958         argv_array_push(&cp.args, "push-check");
 959         argv_array_push(&cp.args, head);
 960         argv_array_push(&cp.args, remote->name);
 961
 962         for (i = 0; i < refspec_nr; i++)
 963                 argv_array_push(&cp.args, refspec[i]);
 964
 965         prepare_submodule_repo_env(&cp.env_array);
 966         cp.git_cmd = 1;
 967         cp.no_stdin = 1;
 968         cp.no_stdout = 1;
 969         cp.dir = path;
 970
 971         /*
 972          * Simply indicate if 'submodule--helper push-check' failed.
 973          * More detailed error information will be provided by the
 974          * child process.
 975          */
 976         if (run_command(&cp))
 977                 die("process for submodule '%s' failed", path);
 978 }
 979
 980 int push_unpushed_submodules(struct oid_array *commits,
 981                              const struct remote *remote,
 982                              const char **refspec, int refspec_nr,
 983                              const struct string_list *push_options,
 984                              int dry_run)
 985 {
 986         int i, ret = 1;
 987         struct string_list needs_pushing = STRING_LIST_INIT_DUP;
 988
 989         if (!find_unpushed_submodules(commits, remote->name, &needs_pushing))
 990                 return 1;
 991
 992         /*
 993          * Verify that the remote and refspec can be propagated to all
 994          * submodules.  This check can be skipped if the remote and refspec
 995          * won't be propagated due to the remote being unconfigured (e.g. a URL
 996          * instead of a remote name).
 997          */
 998         if (remote->origin != REMOTE_UNCONFIGURED) {
 999                 char *head;
1000                 struct object_id head_oid;
1001
1002                 head = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
1003                 if (!head)
1004                         die(_("Failed to resolve HEAD as a valid ref."));
1005
1006                 for (i = 0; i < needs_pushing.nr; i++)
1007                         submodule_push_check(needs_pushing.items[i].string,
1008                                              head, remote,
1009                                              refspec, refspec_nr);
1010                 free(head);
1011         }
1012
1013         /* Actually push the submodules */
1014         for (i = 0; i < needs_pushing.nr; i++) {
1015                 const char *path = needs_pushing.items[i].string;
1016                 fprintf(stderr, "Pushing submodule '%s'\n", path);
1017                 if (!push_submodule(path, remote, refspec, refspec_nr,
1018                                     push_options, dry_run)) {
1019                         fprintf(stderr, "Unable to push submodule '%s'\n", path);
1020                         ret = 0;
1021                 }
1022         }
1023
1024         string_list_clear(&needs_pushing, 0);
1025
1026         return ret;
1027 }
1028
1029 static int append_oid_to_array(const char *ref, const struct object_id *oid,
1030                                int flags, void *data)
1031 {
1032         struct oid_array *array = data;
1033         oid_array_append(array, oid);
1034         return 0;
1035 }
1036
1037 void check_for_new_submodule_commits(struct object_id *oid)
1038 {
1039         if (!initialized_fetch_ref_tips) {
1040                 for_each_ref(append_oid_to_array, &ref_tips_before_fetch);
1041                 initialized_fetch_ref_tips = 1;
1042         }
1043
1044         oid_array_append(&ref_tips_after_fetch, oid);
1045 }
1046
1047 static void calculate_changed_submodule_paths(void)
1048 {
1049         struct argv_array argv = ARGV_ARRAY_INIT;
1050         struct string_list changed_submodules = STRING_LIST_INIT_DUP;
1051         const struct string_list_item *item;
1052
1053         /* No need to check if there are no submodules configured */
1054         if (!submodule_from_path(NULL, NULL))
1055                 return;
1056
1057         argv_array_push(&argv, "--"); /* argv[0] program name */
1058         oid_array_for_each_unique(&ref_tips_after_fetch,
1059                                    append_oid_to_argv, &argv);
1060         argv_array_push(&argv, "--not");
1061         oid_array_for_each_unique(&ref_tips_before_fetch,
1062                                    append_oid_to_argv, &argv);
1063
1064         /*
1065          * Collect all submodules (whether checked out or not) for which new
1066          * commits have been recorded upstream in "changed_submodule_paths".
1067          */
1068         collect_changed_submodules(&changed_submodules, &argv);
1069
1070         for_each_string_list_item(item, &changed_submodules) {
1071                 struct oid_array *commits = item->util;
1072                 const char *path = item->string;
1073
1074                 if (!submodule_has_commits(path, commits))
1075                         string_list_append(&changed_submodule_paths, path);
1076         }
1077
1078         free_submodules_oids(&changed_submodules);
1079         argv_array_clear(&argv);
1080         oid_array_clear(&ref_tips_before_fetch);
1081         oid_array_clear(&ref_tips_after_fetch);
1082         initialized_fetch_ref_tips = 0;
1083 }
1084
1085 int submodule_touches_in_range(struct object_id *excl_oid,
1086                                struct object_id *incl_oid)
1087 {
1088         struct string_list subs = STRING_LIST_INIT_DUP;
1089         struct argv_array args = ARGV_ARRAY_INIT;
1090         int ret;
1091
1092         /* No need to check if there are no submodules configured */
1093         if (!submodule_from_path(NULL, NULL))
1094                 return 0;
1095
1096         argv_array_push(&args, "--"); /* args[0] program name */
1097         argv_array_push(&args, oid_to_hex(incl_oid));
1098         argv_array_push(&args, "--not");
1099         argv_array_push(&args, oid_to_hex(excl_oid));
1100
1101         collect_changed_submodules(&subs, &args);
1102         ret = subs.nr;
1103
1104         argv_array_clear(&args);
1105
1106         free_submodules_oids(&subs);
1107         return ret;
1108 }
1109
1110 struct submodule_parallel_fetch {
1111         int count;
1112         struct argv_array args;
1113         const char *work_tree;
1114         const char *prefix;
1115         int command_line_option;
1116         int default_option;
1117         int quiet;
1118         int result;
1119 };
1120 #define SPF_INIT {0, ARGV_ARRAY_INIT, NULL, NULL, 0, 0, 0, 0}
1121
1122 static int get_next_submodule(struct child_process *cp,
1123                               struct strbuf *err, void *data, void **task_cb)
1124 {
1125         int ret = 0;
1126         struct submodule_parallel_fetch *spf = data;
1127
1128         for (; spf->count < active_nr; spf->count++) {
1129                 struct strbuf submodule_path = STRBUF_INIT;
1130                 struct strbuf submodule_git_dir = STRBUF_INIT;
1131                 struct strbuf submodule_prefix = STRBUF_INIT;
1132                 const struct cache_entry *ce = active_cache[spf->count];
1133                 const char *git_dir, *default_argv;
1134                 const struct submodule *submodule;
1135
1136                 if (!S_ISGITLINK(ce->ce_mode))
1137                         continue;
1138
1139                 submodule = submodule_from_path(&null_oid, ce->name);
1140
1141                 default_argv = "yes";
1142                 if (spf->command_line_option == RECURSE_SUBMODULES_DEFAULT) {
1143                         int fetch_recurse = RECURSE_SUBMODULES_NONE;
1144
1145                         if (submodule) {
1146                                 char *key;
1147                                 const char *value;
1148
1149                                 fetch_recurse = submodule->fetch_recurse;
1150                                 key = xstrfmt("submodule.%s.fetchRecurseSubmodules", submodule->name);
1151                                 if (!repo_config_get_string_const(the_repository, key, &value)) {
1152                                         fetch_recurse = parse_fetch_recurse_submodules_arg(key, value);
1153                                 }
1154                                 free(key);
1155                         }
1156
1157                         if (fetch_recurse != RECURSE_SUBMODULES_NONE) {
1158                                 if (fetch_recurse == RECURSE_SUBMODULES_OFF)
1159                                         continue;
1160                                 if (fetch_recurse == RECURSE_SUBMODULES_ON_DEMAND) {
1161                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1162                                                 continue;
1163                                         default_argv = "on-demand";
1164                                 }
1165                         } else {
1166                                 if (spf->default_option == RECURSE_SUBMODULES_OFF)
1167                                         continue;
1168                                 if (spf->default_option == RECURSE_SUBMODULES_ON_DEMAND) {
1169                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1170                                                 continue;
1171                                         default_argv = "on-demand";
1172                                 }
1173                         }
1174                 } else if (spf->command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
1175                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1176                                 continue;
1177                         default_argv = "on-demand";
1178                 }
1179
1180                 strbuf_addf(&submodule_path, "%s/%s", spf->work_tree, ce->name);
1181                 strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
1182                 strbuf_addf(&submodule_prefix, "%s%s/", spf->prefix, ce->name);
1183                 git_dir = read_gitfile(submodule_git_dir.buf);
1184                 if (!git_dir)
1185                         git_dir = submodule_git_dir.buf;
1186                 if (is_directory(git_dir)) {
1187                         child_process_init(cp);
1188                         cp->dir = strbuf_detach(&submodule_path, NULL);
1189                         prepare_submodule_repo_env(&cp->env_array);
1190                         cp->git_cmd = 1;
1191                         if (!spf->quiet)
1192                                 strbuf_addf(err, "Fetching submodule %s%s\n",
1193                                             spf->prefix, ce->name);
1194                         argv_array_init(&cp->args);
1195                         argv_array_pushv(&cp->args, spf->args.argv);
1196                         argv_array_push(&cp->args, default_argv);
1197                         argv_array_push(&cp->args, "--submodule-prefix");
1198                         argv_array_push(&cp->args, submodule_prefix.buf);
1199                         ret = 1;
1200                 }
1201                 strbuf_release(&submodule_path);
1202                 strbuf_release(&submodule_git_dir);
1203                 strbuf_release(&submodule_prefix);
1204                 if (ret) {
1205                         spf->count++;
1206                         return 1;
1207                 }
1208         }
1209         return 0;
1210 }
1211
1212 static int fetch_start_failure(struct strbuf *err,
1213                                void *cb, void *task_cb)
1214 {
1215         struct submodule_parallel_fetch *spf = cb;
1216
1217         spf->result = 1;
1218
1219         return 0;
1220 }
1221
1222 static int fetch_finish(int retvalue, struct strbuf *err,
1223                         void *cb, void *task_cb)
1224 {
1225         struct submodule_parallel_fetch *spf = cb;
1226
1227         if (retvalue)
1228                 spf->result = 1;
1229
1230         return 0;
1231 }
1232
1233 int fetch_populated_submodules(const struct argv_array *options,
1234                                const char *prefix, int command_line_option,
1235                                int default_option,
1236                                int quiet, int max_parallel_jobs)
1237 {
1238         int i;
1239         struct submodule_parallel_fetch spf = SPF_INIT;
1240
1241         spf.work_tree = get_git_work_tree();
1242         spf.command_line_option = command_line_option;
1243         spf.default_option = default_option;
1244         spf.quiet = quiet;
1245         spf.prefix = prefix;
1246
1247         if (!spf.work_tree)
1248                 goto out;
1249
1250         if (read_cache() < 0)
1251                 die("index file corrupt");
1252
1253         argv_array_push(&spf.args, "fetch");
1254         for (i = 0; i < options->argc; i++)
1255                 argv_array_push(&spf.args, options->argv[i]);
1256         argv_array_push(&spf.args, "--recurse-submodules-default");
1257         /* default value, "--submodule-prefix" and its value are added later */
1258
1259         calculate_changed_submodule_paths();
1260         run_processes_parallel(max_parallel_jobs,
1261                                get_next_submodule,
1262                                fetch_start_failure,
1263                                fetch_finish,
1264                                &spf);
1265
1266         argv_array_clear(&spf.args);
1267 out:
1268         string_list_clear(&changed_submodule_paths, 1);
1269         return spf.result;
1270 }
1271
1272 unsigned is_submodule_modified(const char *path, int ignore_untracked)
1273 {
1274         struct child_process cp = CHILD_PROCESS_INIT;
1275         struct strbuf buf = STRBUF_INIT;
1276         FILE *fp;
1277         unsigned dirty_submodule = 0;
1278         const char *git_dir;
1279         int ignore_cp_exit_code = 0;
1280
1281         strbuf_addf(&buf, "%s/.git", path);
1282         git_dir = read_gitfile(buf.buf);
1283         if (!git_dir)
1284                 git_dir = buf.buf;
1285         if (!is_git_directory(git_dir)) {
1286                 if (is_directory(git_dir))
1287                         die(_("'%s' not recognized as a git repository"), git_dir);
1288                 strbuf_release(&buf);
1289                 /* The submodule is not checked out, so it is not modified */
1290                 return 0;
1291         }
1292         strbuf_reset(&buf);
1293
1294         argv_array_pushl(&cp.args, "status", "--porcelain=2", NULL);
1295         if (ignore_untracked)
1296                 argv_array_push(&cp.args, "-uno");
1297
1298         prepare_submodule_repo_env(&cp.env_array);
1299         cp.git_cmd = 1;
1300         cp.no_stdin = 1;
1301         cp.out = -1;
1302         cp.dir = path;
1303         if (start_command(&cp))
1304                 die("Could not run 'git status --porcelain=2' in submodule %s", path);
1305
1306         fp = xfdopen(cp.out, "r");
1307         while (strbuf_getwholeline(&buf, fp, '\n') != EOF) {
1308                 /* regular untracked files */
1309                 if (buf.buf[0] == '?')
1310                         dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
1311
1312                 if (buf.buf[0] == 'u' ||
1313                     buf.buf[0] == '1' ||
1314                     buf.buf[0] == '2') {
1315                         /* T = line type, XY = status, SSSS = submodule state */
1316                         if (buf.len < strlen("T XY SSSS"))
1317                                 die("BUG: invalid status --porcelain=2 line %s",
1318                                     buf.buf);
1319
1320                         if (buf.buf[5] == 'S' && buf.buf[8] == 'U')
1321                                 /* nested untracked file */
1322                                 dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
1323
1324                         if (buf.buf[0] == 'u' ||
1325                             buf.buf[0] == '2' ||
1326                             memcmp(buf.buf + 5, "S..U", 4))
1327                                 /* other change */
1328                                 dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
1329                 }
1330
1331                 if ((dirty_submodule & DIRTY_SUBMODULE_MODIFIED) &&
1332                     ((dirty_submodule & DIRTY_SUBMODULE_UNTRACKED) ||
1333                      ignore_untracked)) {
1334                         /*
1335                          * We're not interested in any further information from
1336                          * the child any more, neither output nor its exit code.
1337                          */
1338                         ignore_cp_exit_code = 1;
1339                         break;
1340                 }
1341         }
1342         fclose(fp);
1343
1344         if (finish_command(&cp) && !ignore_cp_exit_code)
1345                 die("'git status --porcelain=2' failed in submodule %s", path);
1346
1347         strbuf_release(&buf);
1348         return dirty_submodule;
1349 }
1350
1351 int submodule_uses_gitfile(const char *path)
1352 {
1353         struct child_process cp = CHILD_PROCESS_INIT;
1354         const char *argv[] = {
1355                 "submodule",
1356                 "foreach",
1357                 "--quiet",
1358                 "--recursive",
1359                 "test -f .git",
1360                 NULL,
1361         };
1362         struct strbuf buf = STRBUF_INIT;
1363         const char *git_dir;
1364
1365         strbuf_addf(&buf, "%s/.git", path);
1366         git_dir = read_gitfile(buf.buf);
1367         if (!git_dir) {
1368                 strbuf_release(&buf);
1369                 return 0;
1370         }
1371         strbuf_release(&buf);
1372
1373         /* Now test that all nested submodules use a gitfile too */
1374         cp.argv = argv;
1375         prepare_submodule_repo_env(&cp.env_array);
1376         cp.git_cmd = 1;
1377         cp.no_stdin = 1;
1378         cp.no_stderr = 1;
1379         cp.no_stdout = 1;
1380         cp.dir = path;
1381         if (run_command(&cp))
1382                 return 0;
1383
1384         return 1;
1385 }
1386
1387 /*
1388  * Check if it is a bad idea to remove a submodule, i.e. if we'd lose data
1389  * when doing so.
1390  *
1391  * Return 1 if we'd lose data, return 0 if the removal is fine,
1392  * and negative values for errors.
1393  */
1394 int bad_to_remove_submodule(const char *path, unsigned flags)
1395 {
1396         ssize_t len;
1397         struct child_process cp = CHILD_PROCESS_INIT;
1398         struct strbuf buf = STRBUF_INIT;
1399         int ret = 0;
1400
1401         if (!file_exists(path) || is_empty_dir(path))
1402                 return 0;
1403
1404         if (!submodule_uses_gitfile(path))
1405                 return 1;
1406
1407         argv_array_pushl(&cp.args, "status", "--porcelain",
1408                                    "--ignore-submodules=none", NULL);
1409
1410         if (flags & SUBMODULE_REMOVAL_IGNORE_UNTRACKED)
1411                 argv_array_push(&cp.args, "-uno");
1412         else
1413                 argv_array_push(&cp.args, "-uall");
1414
1415         if (!(flags & SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED))
1416                 argv_array_push(&cp.args, "--ignored");
1417
1418         prepare_submodule_repo_env(&cp.env_array);
1419         cp.git_cmd = 1;
1420         cp.no_stdin = 1;
1421         cp.out = -1;
1422         cp.dir = path;
1423         if (start_command(&cp)) {
1424                 if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
1425                         die(_("could not start 'git status' in submodule '%s'"),
1426                                 path);
1427                 ret = -1;
1428                 goto out;
1429         }
1430
1431         len = strbuf_read(&buf, cp.out, 1024);
1432         if (len > 2)
1433                 ret = 1;
1434         close(cp.out);
1435
1436         if (finish_command(&cp)) {
1437                 if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
1438                         die(_("could not run 'git status' in submodule '%s'"),
1439                                 path);
1440                 ret = -1;
1441         }
1442 out:
1443         strbuf_release(&buf);
1444         return ret;
1445 }
1446
1447 static const char *get_super_prefix_or_empty(void)
1448 {
1449         const char *s = get_super_prefix();
1450         if (!s)
1451                 s = "";
1452         return s;
1453 }
1454
1455 static int submodule_has_dirty_index(const struct submodule *sub)
1456 {
1457         struct child_process cp = CHILD_PROCESS_INIT;
1458
1459         prepare_submodule_repo_env(&cp.env_array);
1460
1461         cp.git_cmd = 1;
1462         argv_array_pushl(&cp.args, "diff-index", "--quiet",
1463                                    "--cached", "HEAD", NULL);
1464         cp.no_stdin = 1;
1465         cp.no_stdout = 1;
1466         cp.dir = sub->path;
1467         if (start_command(&cp))
1468                 die("could not recurse into submodule '%s'", sub->path);
1469
1470         return finish_command(&cp);
1471 }
1472
1473 static void submodule_reset_index(const char *path)
1474 {
1475         struct child_process cp = CHILD_PROCESS_INIT;
1476         prepare_submodule_repo_env(&cp.env_array);
1477
1478         cp.git_cmd = 1;
1479         cp.no_stdin = 1;
1480         cp.dir = path;
1481
1482         argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
1483                                    get_super_prefix_or_empty(), path);
1484         argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
1485
1486         argv_array_push(&cp.args, EMPTY_TREE_SHA1_HEX);
1487
1488         if (run_command(&cp))
1489                 die("could not reset submodule index");
1490 }
1491
1492 /**
1493  * Moves a submodule at a given path from a given head to another new head.
1494  * For edge cases (a submodule coming into existence or removing a submodule)
1495  * pass NULL for old or new respectively.
1496  */
1497 int submodule_move_head(const char *path,
1498                          const char *old,
1499                          const char *new,
1500                          unsigned flags)
1501 {
1502         int ret = 0;
1503         struct child_process cp = CHILD_PROCESS_INIT;
1504         const struct submodule *sub;
1505         int *error_code_ptr, error_code;
1506
1507         if (!is_submodule_active(the_repository, path))
1508                 return 0;
1509
1510         if (flags & SUBMODULE_MOVE_HEAD_FORCE)
1511                 /*
1512                  * Pass non NULL pointer to is_submodule_populated_gently
1513                  * to prevent die()-ing. We'll use connect_work_tree_and_git_dir
1514                  * to fixup the submodule in the force case later.
1515                  */
1516                 error_code_ptr = &error_code;
1517         else
1518                 error_code_ptr = NULL;
1519
1520         if (old && !is_submodule_populated_gently(path, error_code_ptr))
1521                 return 0;
1522
1523         sub = submodule_from_path(&null_oid, path);
1524
1525         if (!sub)
1526                 die("BUG: could not get submodule information for '%s'", path);
1527
1528         if (old && !(flags & SUBMODULE_MOVE_HEAD_FORCE)) {
1529                 /* Check if the submodule has a dirty index. */
1530                 if (submodule_has_dirty_index(sub))
1531                         return error(_("submodule '%s' has dirty index"), path);
1532         }
1533
1534         if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
1535                 if (old) {
1536                         if (!submodule_uses_gitfile(path))
1537                                 absorb_git_dir_into_superproject("", path,
1538                                         ABSORB_GITDIR_RECURSE_SUBMODULES);
1539                 } else {
1540                         char *gitdir = xstrfmt("%s/modules/%s",
1541                                     get_git_common_dir(), sub->name);
1542                         connect_work_tree_and_git_dir(path, gitdir);
1543                         free(gitdir);
1544
1545                         /* make sure the index is clean as well */
1546                         submodule_reset_index(path);
1547                 }
1548
1549                 if (old && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
1550                         char *gitdir = xstrfmt("%s/modules/%s",
1551                                     get_git_common_dir(), sub->name);
1552                         connect_work_tree_and_git_dir(path, gitdir);
1553                         free(gitdir);
1554                 }
1555         }
1556
1557         prepare_submodule_repo_env(&cp.env_array);
1558
1559         cp.git_cmd = 1;
1560         cp.no_stdin = 1;
1561         cp.dir = path;
1562
1563         argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
1564                         get_super_prefix_or_empty(), path);
1565         argv_array_pushl(&cp.args, "read-tree", "--recurse-submodules", NULL);
1566
1567         if (flags & SUBMODULE_MOVE_HEAD_DRY_RUN)
1568                 argv_array_push(&cp.args, "-n");
1569         else
1570                 argv_array_push(&cp.args, "-u");
1571
1572         if (flags & SUBMODULE_MOVE_HEAD_FORCE)
1573                 argv_array_push(&cp.args, "--reset");
1574         else
1575                 argv_array_push(&cp.args, "-m");
1576
1577         argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX);
1578         argv_array_push(&cp.args, new ? new : EMPTY_TREE_SHA1_HEX);
1579
1580         if (run_command(&cp)) {
1581                 ret = -1;
1582                 goto out;
1583         }
1584
1585         if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
1586                 if (new) {
1587                         child_process_init(&cp);
1588                         /* also set the HEAD accordingly */
1589                         cp.git_cmd = 1;
1590                         cp.no_stdin = 1;
1591                         cp.dir = path;
1592
1593                         prepare_submodule_repo_env(&cp.env_array);
1594                         argv_array_pushl(&cp.args, "update-ref", "HEAD", new, NULL);
1595
1596                         if (run_command(&cp)) {
1597                                 ret = -1;
1598                                 goto out;
1599                         }
1600                 } else {
1601                         struct strbuf sb = STRBUF_INIT;
1602
1603                         strbuf_addf(&sb, "%s/.git", path);
1604                         unlink_or_warn(sb.buf);
1605                         strbuf_release(&sb);
1606
1607                         if (is_empty_dir(path))
1608                                 rmdir_or_warn(path);
1609                 }
1610         }
1611 out:
1612         return ret;
1613 }
1614
1615 static int find_first_merges(struct object_array *result, const char *path,
1616                 struct commit *a, struct commit *b)
1617 {
1618         int i, j;
1619         struct object_array merges = OBJECT_ARRAY_INIT;
1620         struct commit *commit;
1621         int contains_another;
1622
1623         char merged_revision[42];
1624         const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
1625                                    "--all", merged_revision, NULL };
1626         struct rev_info revs;
1627         struct setup_revision_opt rev_opts;
1628
1629         memset(result, 0, sizeof(struct object_array));
1630         memset(&rev_opts, 0, sizeof(rev_opts));
1631
1632         /* get all revisions that merge commit a */
1633         xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
1634                         oid_to_hex(&a->object.oid));
1635         init_revisions(&revs, NULL);
1636         rev_opts.submodule = path;
1637         /* FIXME: can't handle linked worktrees in submodules yet */
1638         revs.single_worktree = path != NULL;
1639         setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
1640
1641         /* save all revisions from the above list that contain b */
1642         if (prepare_revision_walk(&revs))
1643                 die("revision walk setup failed");
1644         while ((commit = get_revision(&revs)) != NULL) {
1645                 struct object *o = &(commit->object);
1646                 if (in_merge_bases(b, commit))
1647                         add_object_array(o, NULL, &merges);
1648         }
1649         reset_revision_walk();
1650
1651         /* Now we've got all merges that contain a and b. Prune all
1652          * merges that contain another found merge and save them in
1653          * result.
1654          */
1655         for (i = 0; i < merges.nr; i++) {
1656                 struct commit *m1 = (struct commit *) merges.objects[i].item;
1657
1658                 contains_another = 0;
1659                 for (j = 0; j < merges.nr; j++) {
1660                         struct commit *m2 = (struct commit *) merges.objects[j].item;
1661                         if (i != j && in_merge_bases(m2, m1)) {
1662                                 contains_another = 1;
1663                                 break;
1664                         }
1665                 }
1666
1667                 if (!contains_another)
1668                         add_object_array(merges.objects[i].item, NULL, result);
1669         }
1670
1671         free(merges.objects);
1672         return result->nr;
1673 }
1674
1675 static void print_commit(struct commit *commit)
1676 {
1677         struct strbuf sb = STRBUF_INIT;
1678         struct pretty_print_context ctx = {0};
1679         ctx.date_mode.type = DATE_NORMAL;
1680         format_commit_message(commit, " %h: %m %s", &sb, &ctx);
1681         fprintf(stderr, "%s\n", sb.buf);
1682         strbuf_release(&sb);
1683 }
1684
1685 #define MERGE_WARNING(path, msg) \
1686         warning("Failed to merge submodule %s (%s)", path, msg);
1687
1688 int merge_submodule(struct object_id *result, const char *path,
1689                     const struct object_id *base, const struct object_id *a,
1690                     const struct object_id *b, int search)
1691 {
1692         struct commit *commit_base, *commit_a, *commit_b;
1693         int parent_count;
1694         struct object_array merges;
1695
1696         int i;
1697
1698         /* store a in result in case we fail */
1699         oidcpy(result, a);
1700
1701         /* we can not handle deletion conflicts */
1702         if (is_null_oid(base))
1703                 return 0;
1704         if (is_null_oid(a))
1705                 return 0;
1706         if (is_null_oid(b))
1707                 return 0;
1708
1709         if (add_submodule_odb(path)) {
1710                 MERGE_WARNING(path, "not checked out");
1711                 return 0;
1712         }
1713
1714         if (!(commit_base = lookup_commit_reference(base)) ||
1715             !(commit_a = lookup_commit_reference(a)) ||
1716             !(commit_b = lookup_commit_reference(b))) {
1717                 MERGE_WARNING(path, "commits not present");
1718                 return 0;
1719         }
1720
1721         /* check whether both changes are forward */
1722         if (!in_merge_bases(commit_base, commit_a) ||
1723             !in_merge_bases(commit_base, commit_b)) {
1724                 MERGE_WARNING(path, "commits don't follow merge-base");
1725                 return 0;
1726         }
1727
1728         /* Case #1: a is contained in b or vice versa */
1729         if (in_merge_bases(commit_a, commit_b)) {
1730                 oidcpy(result, b);
1731                 return 1;
1732         }
1733         if (in_merge_bases(commit_b, commit_a)) {
1734                 oidcpy(result, a);
1735                 return 1;
1736         }
1737
1738         /*
1739          * Case #2: There are one or more merges that contain a and b in
1740          * the submodule. If there is only one, then present it as a
1741          * suggestion to the user, but leave it marked unmerged so the
1742          * user needs to confirm the resolution.
1743          */
1744
1745         /* Skip the search if makes no sense to the calling context.  */
1746         if (!search)
1747                 return 0;
1748
1749         /* find commit which merges them */
1750         parent_count = find_first_merges(&merges, path, commit_a, commit_b);
1751         switch (parent_count) {
1752         case 0:
1753                 MERGE_WARNING(path, "merge following commits not found");
1754                 break;
1755
1756         case 1:
1757                 MERGE_WARNING(path, "not fast-forward");
1758                 fprintf(stderr, "Found a possible merge resolution "
1759                                 "for the submodule:\n");
1760                 print_commit((struct commit *) merges.objects[0].item);
1761                 fprintf(stderr,
1762                         "If this is correct simply add it to the index "
1763                         "for example\n"
1764                         "by using:\n\n"
1765                         "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
1766                         "which will accept this suggestion.\n",
1767                         oid_to_hex(&merges.objects[0].item->oid), path);
1768                 break;
1769
1770         default:
1771                 MERGE_WARNING(path, "multiple merges found");
1772                 for (i = 0; i < merges.nr; i++)
1773                         print_commit((struct commit *) merges.objects[i].item);
1774         }
1775
1776         free(merges.objects);
1777         return 0;
1778 }
1779
1780 /*
1781  * Embeds a single submodules git directory into the superprojects git dir,
1782  * non recursively.
1783  */
1784 static void relocate_single_git_dir_into_superproject(const char *prefix,
1785                                                       const char *path)
1786 {
1787         char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
1788         const char *new_git_dir;
1789         const struct submodule *sub;
1790
1791         if (submodule_uses_worktrees(path))
1792                 die(_("relocate_gitdir for submodule '%s' with "
1793                       "more than one worktree not supported"), path);
1794
1795         old_git_dir = xstrfmt("%s/.git", path);
1796         if (read_gitfile(old_git_dir))
1797                 /* If it is an actual gitfile, it doesn't need migration. */
1798                 return;
1799
1800         real_old_git_dir = real_pathdup(old_git_dir, 1);
1801
1802         sub = submodule_from_path(&null_oid, path);
1803         if (!sub)
1804                 die(_("could not lookup name for submodule '%s'"), path);
1805
1806         new_git_dir = git_path("modules/%s", sub->name);
1807         if (safe_create_leading_directories_const(new_git_dir) < 0)
1808                 die(_("could not create directory '%s'"), new_git_dir);
1809         real_new_git_dir = real_pathdup(new_git_dir, 1);
1810
1811         fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
1812                 get_super_prefix_or_empty(), path,
1813                 real_old_git_dir, real_new_git_dir);
1814
1815         relocate_gitdir(path, real_old_git_dir, real_new_git_dir);
1816
1817         free(old_git_dir);
1818         free(real_old_git_dir);
1819         free(real_new_git_dir);
1820 }
1821
1822 /*
1823  * Migrate the git directory of the submodule given by path from
1824  * having its git directory within the working tree to the git dir nested
1825  * in its superprojects git dir under modules/.
1826  */
1827 void absorb_git_dir_into_superproject(const char *prefix,
1828                                       const char *path,
1829                                       unsigned flags)
1830 {
1831         int err_code;
1832         const char *sub_git_dir;
1833         struct strbuf gitdir = STRBUF_INIT;
1834         strbuf_addf(&gitdir, "%s/.git", path);
1835         sub_git_dir = resolve_gitdir_gently(gitdir.buf, &err_code);
1836
1837         /* Not populated? */
1838         if (!sub_git_dir) {
1839                 const struct submodule *sub;
1840
1841                 if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
1842                         /* unpopulated as expected */
1843                         strbuf_release(&gitdir);
1844                         return;
1845                 }
1846
1847                 if (err_code != READ_GITFILE_ERR_NOT_A_REPO)
1848                         /* We don't know what broke here. */
1849                         read_gitfile_error_die(err_code, path, NULL);
1850
1851                 /*
1852                 * Maybe populated, but no git directory was found?
1853                 * This can happen if the superproject is a submodule
1854                 * itself and was just absorbed. The absorption of the
1855                 * superproject did not rewrite the git file links yet,
1856                 * fix it now.
1857                 */
1858                 sub = submodule_from_path(&null_oid, path);
1859                 if (!sub)
1860                         die(_("could not lookup name for submodule '%s'"), path);
1861                 connect_work_tree_and_git_dir(path,
1862                         git_path("modules/%s", sub->name));
1863         } else {
1864                 /* Is it already absorbed into the superprojects git dir? */
1865                 char *real_sub_git_dir = real_pathdup(sub_git_dir, 1);
1866                 char *real_common_git_dir = real_pathdup(get_git_common_dir(), 1);
1867
1868                 if (!starts_with(real_sub_git_dir, real_common_git_dir))
1869                         relocate_single_git_dir_into_superproject(prefix, path);
1870
1871                 free(real_sub_git_dir);
1872                 free(real_common_git_dir);
1873         }
1874         strbuf_release(&gitdir);
1875
1876         if (flags & ABSORB_GITDIR_RECURSE_SUBMODULES) {
1877                 struct child_process cp = CHILD_PROCESS_INIT;
1878                 struct strbuf sb = STRBUF_INIT;
1879
1880                 if (flags & ~ABSORB_GITDIR_RECURSE_SUBMODULES)
1881                         die("BUG: we don't know how to pass the flags down?");
1882
1883                 strbuf_addstr(&sb, get_super_prefix_or_empty());
1884                 strbuf_addstr(&sb, path);
1885                 strbuf_addch(&sb, '/');
1886
1887                 cp.dir = path;
1888                 cp.git_cmd = 1;
1889                 cp.no_stdin = 1;
1890                 argv_array_pushl(&cp.args, "--super-prefix", sb.buf,
1891                                            "submodule--helper",
1892                                            "absorb-git-dirs", NULL);
1893                 prepare_submodule_repo_env(&cp.env_array);
1894                 if (run_command(&cp))
1895                         die(_("could not recurse into submodule '%s'"), path);
1896
1897                 strbuf_release(&sb);
1898         }
1899 }
1900
1901 const char *get_superproject_working_tree(void)
1902 {
1903         struct child_process cp = CHILD_PROCESS_INIT;
1904         struct strbuf sb = STRBUF_INIT;
1905         const char *one_up = real_path_if_valid("../");
1906         const char *cwd = xgetcwd();
1907         const char *ret = NULL;
1908         const char *subpath;
1909         int code;
1910         ssize_t len;
1911
1912         if (!is_inside_work_tree())
1913                 /*
1914                  * FIXME:
1915                  * We might have a superproject, but it is harder
1916                  * to determine.
1917                  */
1918                 return NULL;
1919
1920         if (!one_up)
1921                 return NULL;
1922
1923         subpath = relative_path(cwd, one_up, &sb);
1924
1925         prepare_submodule_repo_env(&cp.env_array);
1926         argv_array_pop(&cp.env_array);
1927
1928         argv_array_pushl(&cp.args, "--literal-pathspecs", "-C", "..",
1929                         "ls-files", "-z", "--stage", "--full-name", "--",
1930                         subpath, NULL);
1931         strbuf_reset(&sb);
1932
1933         cp.no_stdin = 1;
1934         cp.no_stderr = 1;
1935         cp.out = -1;
1936         cp.git_cmd = 1;
1937
1938         if (start_command(&cp))
1939                 die(_("could not start ls-files in .."));
1940
1941         len = strbuf_read(&sb, cp.out, PATH_MAX);
1942         close(cp.out);
1943
1944         if (starts_with(sb.buf, "160000")) {
1945                 int super_sub_len;
1946                 int cwd_len = strlen(cwd);
1947                 char *super_sub, *super_wt;
1948
1949                 /*
1950                  * There is a superproject having this repo as a submodule.
1951                  * The format is <mode> SP <hash> SP <stage> TAB <full name> \0,
1952                  * We're only interested in the name after the tab.
1953                  */
1954                 super_sub = strchr(sb.buf, '\t') + 1;
1955                 super_sub_len = sb.buf + sb.len - super_sub - 1;
1956
1957                 if (super_sub_len > cwd_len ||
1958                     strcmp(&cwd[cwd_len - super_sub_len], super_sub))
1959                         die (_("BUG: returned path string doesn't match cwd?"));
1960
1961                 super_wt = xstrdup(cwd);
1962                 super_wt[cwd_len - super_sub_len] = '\0';
1963
1964                 ret = real_path(super_wt);
1965                 free(super_wt);
1966         }
1967         strbuf_release(&sb);
1968
1969         code = finish_command(&cp);
1970
1971         if (code == 128)
1972                 /* '../' is not a git repository */
1973                 return NULL;
1974         if (code == 0 && len == 0)
1975                 /* There is an unrelated git repository at '../' */
1976                 return NULL;
1977         if (code)
1978                 die(_("ls-tree returned unexpected return code %d"), code);
1979
1980         return ret;
1981 }
1982
1983 int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
1984 {
1985         const struct submodule *sub;
1986         const char *git_dir;
1987         int ret = 0;
1988
1989         strbuf_reset(buf);
1990         strbuf_addstr(buf, submodule);
1991         strbuf_complete(buf, '/');
1992         strbuf_addstr(buf, ".git");
1993
1994         git_dir = read_gitfile(buf->buf);
1995         if (git_dir) {
1996                 strbuf_reset(buf);
1997                 strbuf_addstr(buf, git_dir);
1998         }
1999         if (!is_git_directory(buf->buf)) {
2000                 sub = submodule_from_path(&null_oid, submodule);
2001                 if (!sub) {
2002                         ret = -1;
2003                         goto cleanup;
2004                 }
2005                 strbuf_reset(buf);
2006                 strbuf_git_path(buf, "%s/%s", "modules", sub->name);
2007         }
2008
2009 cleanup:
2010         return ret;
2011 }