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_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
  24 static int config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
  25 static int parallel_jobs = 1;
  26 static struct string_list changed_submodule_paths = STRING_LIST_INIT_DUP;
  27 static int initialized_fetch_ref_tips;
  28 static struct oid_array ref_tips_before_fetch;
  29 static struct oid_array ref_tips_after_fetch;
  30
  31 /*
  32  * The following flag is set if the .gitmodules file is unmerged. We then
  33  * disable recursion for all submodules where .git/config doesn't have a
  34  * matching config entry because we can't guess what might be configured in
  35  * .gitmodules unless the user resolves the conflict. When a command line
  36  * option is given (which always overrides configuration) this flag will be
  37  * ignored.
  38  */
  39 static int gitmodules_is_unmerged;
  40
  41 /*
  42  * This flag is set if the .gitmodules file had unstaged modifications on
  43  * startup. This must be checked before allowing modifications to the
  44  * .gitmodules file with the intention to stage them later, because when
  45  * continuing we would stage the modifications the user didn't stage herself
  46  * too. That might change in a future version when we learn to stage the
  47  * changes we do ourselves without staging any previous modifications.
  48  */
  49 static int gitmodules_is_modified;
  50
  51 int is_staging_gitmodules_ok(void)
  52 {
  53         return !gitmodules_is_modified;
  54 }
  55
  56 /*
  57  * Try to update the "path" entry in the "submodule.<name>" section of the
  58  * .gitmodules file. Return 0 only if a .gitmodules file was found, a section
  59  * with the correct path=<oldpath> setting was found and we could update it.
  60  */
  61 int update_path_in_gitmodules(const char *oldpath, const char *newpath)
  62 {
  63         struct strbuf entry = STRBUF_INIT;
  64         const struct submodule *submodule;
  65
  66         if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
  67                 return -1;
  68
  69         if (gitmodules_is_unmerged)
  70                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
  71
  72         submodule = submodule_from_path(null_sha1, oldpath);
  73         if (!submodule || !submodule->name) {
  74                 warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
  75                 return -1;
  76         }
  77         strbuf_addstr(&entry, "submodule.");
  78         strbuf_addstr(&entry, submodule->name);
  79         strbuf_addstr(&entry, ".path");
  80         if (git_config_set_in_file_gently(".gitmodules", entry.buf, newpath) < 0) {
  81                 /* Maybe the user already did that, don't error out here */
  82                 warning(_("Could not update .gitmodules entry %s"), entry.buf);
  83                 strbuf_release(&entry);
  84                 return -1;
  85         }
  86         strbuf_release(&entry);
  87         return 0;
  88 }
  89
  90 /*
  91  * Try to remove the "submodule.<name>" section from .gitmodules where the given
  92  * path is configured. Return 0 only if a .gitmodules file was found, a section
  93  * with the correct path=<path> setting was found and we could remove it.
  94  */
  95 int remove_path_from_gitmodules(const char *path)
  96 {
  97         struct strbuf sect = STRBUF_INIT;
  98         const struct submodule *submodule;
  99
 100         if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
 101                 return -1;
 102
 103         if (gitmodules_is_unmerged)
 104                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
 105
 106         submodule = submodule_from_path(null_sha1, path);
 107         if (!submodule || !submodule->name) {
 108                 warning(_("Could not find section in .gitmodules where path=%s"), path);
 109                 return -1;
 110         }
 111         strbuf_addstr(&sect, "submodule.");
 112         strbuf_addstr(&sect, submodule->name);
 113         if (git_config_rename_section_in_file(".gitmodules", sect.buf, NULL) < 0) {
 114                 /* Maybe the user already did that, don't error out here */
 115                 warning(_("Could not remove .gitmodules entry for %s"), path);
 116                 strbuf_release(&sect);
 117                 return -1;
 118         }
 119         strbuf_release(&sect);
 120         return 0;
 121 }
 122
 123 void stage_updated_gitmodules(void)
 124 {
 125         if (add_file_to_cache(".gitmodules", 0))
 126                 die(_("staging updated .gitmodules failed"));
 127 }
 128
 129 static int add_submodule_odb(const char *path)
 130 {
 131         struct strbuf objects_directory = STRBUF_INIT;
 132         int ret = 0;
 133
 134         ret = strbuf_git_path_submodule(&objects_directory, path, "objects/");
 135         if (ret)
 136                 goto done;
 137         if (!is_directory(objects_directory.buf)) {
 138                 ret = -1;
 139                 goto done;
 140         }
 141         add_to_alternates_memory(objects_directory.buf);
 142 done:
 143         strbuf_release(&objects_directory);
 144         return ret;
 145 }
 146
 147 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
 148                                              const char *path)
 149 {
 150         const struct submodule *submodule = submodule_from_path(null_sha1, path);
 151         if (submodule) {
 152                 if (submodule->ignore)
 153                         handle_ignore_submodules_arg(diffopt, submodule->ignore);
 154                 else if (gitmodules_is_unmerged)
 155                         DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 156         }
 157 }
 158
 159 /* For loading from the .gitmodules file. */
 160 static int git_modules_config(const char *var, const char *value, void *cb)
 161 {
 162         if (!strcmp(var, "submodule.fetchjobs")) {
 163                 parallel_jobs = git_config_int(var, value);
 164                 if (parallel_jobs < 0)
 165                         die(_("negative values not allowed for submodule.fetchJobs"));
 166                 return 0;
 167         } else if (starts_with(var, "submodule."))
 168                 return parse_submodule_config_option(var, value);
 169         else if (!strcmp(var, "fetch.recursesubmodules")) {
 170                 config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
 171                 return 0;
 172         }
 173         return 0;
 174 }
 175
 176 /* Loads all submodule settings from the config. */
 177 int submodule_config(const char *var, const char *value, void *cb)
 178 {
 179         if (!strcmp(var, "submodule.recurse")) {
 180                 int v = git_config_bool(var, value) ?
 181                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 182                 config_update_recurse_submodules = v;
 183                 return 0;
 184         } else {
 185                 return git_modules_config(var, value, cb);
 186         }
 187 }
 188
 189 /* Cheap function that only determines if we're interested in submodules at all */
 190 int git_default_submodule_config(const char *var, const char *value, void *cb)
 191 {
 192         if (!strcmp(var, "submodule.recurse")) {
 193                 int v = git_config_bool(var, value) ?
 194                         RECURSE_SUBMODULES_ON : RECURSE_SUBMODULES_OFF;
 195                 config_update_recurse_submodules = v;
 196         }
 197         return 0;
 198 }
 199
 200 int option_parse_recurse_submodules_worktree_updater(const struct option *opt,
 201                                                      const char *arg, int unset)
 202 {
 203         if (unset) {
 204                 config_update_recurse_submodules = RECURSE_SUBMODULES_OFF;
 205                 return 0;
 206         }
 207         if (arg)
 208                 config_update_recurse_submodules =
 209                         parse_update_recurse_submodules_arg(opt->long_name,
 210                                                             arg);
 211         else
 212                 config_update_recurse_submodules = RECURSE_SUBMODULES_ON;
 213
 214         return 0;
 215 }
 216
 217 void load_submodule_cache(void)
 218 {
 219         if (config_update_recurse_submodules == RECURSE_SUBMODULES_OFF)
 220                 return;
 221
 222         gitmodules_config();
 223         git_config(submodule_config, NULL);
 224 }
 225
 226 void gitmodules_config(void)
 227 {
 228         const char *work_tree = get_git_work_tree();
 229         if (work_tree) {
 230                 struct strbuf gitmodules_path = STRBUF_INIT;
 231                 int pos;
 232                 strbuf_addstr(&gitmodules_path, work_tree);
 233                 strbuf_addstr(&gitmodules_path, "/.gitmodules");
 234                 if (read_cache() < 0)
 235                         die("index file corrupt");
 236                 pos = cache_name_pos(".gitmodules", 11);
 237                 if (pos < 0) { /* .gitmodules not found or isn't merged */
 238                         pos = -1 - pos;
 239                         if (active_nr > pos) {  /* there is a .gitmodules */
 240                                 const struct cache_entry *ce = active_cache[pos];
 241                                 if (ce_namelen(ce) == 11 &&
 242                                     !memcmp(ce->name, ".gitmodules", 11))
 243                                         gitmodules_is_unmerged = 1;
 244                         }
 245                 } else if (pos < active_nr) {
 246                         struct stat st;
 247                         if (lstat(".gitmodules", &st) == 0 &&
 248                             ce_match_stat(active_cache[pos], &st, 0) & DATA_CHANGED)
 249                                 gitmodules_is_modified = 1;
 250                 }
 251
 252                 if (!gitmodules_is_unmerged)
 253                         git_config_from_file(git_modules_config,
 254                                 gitmodules_path.buf, NULL);
 255                 strbuf_release(&gitmodules_path);
 256         }
 257 }
 258
 259 static int gitmodules_cb(const char *var, const char *value, void *data)
 260 {
 261         struct repository *repo = data;
 262         return submodule_config_option(repo, var, value);
 263 }
 264
 265 void repo_read_gitmodules(struct repository *repo)
 266 {
 267         char *gitmodules_path = repo_worktree_path(repo, ".gitmodules");
 268
 269         git_config_from_file(gitmodules_cb, gitmodules_path, repo);
 270         free(gitmodules_path);
 271 }
 272
 273 void gitmodules_config_sha1(const unsigned char *commit_sha1)
 274 {
 275         struct strbuf rev = STRBUF_INIT;
 276         unsigned char sha1[20];
 277
 278         if (gitmodule_sha1_from_commit(commit_sha1, sha1, &rev)) {
 279                 git_config_from_blob_sha1(git_modules_config, rev.buf,
 280                                           sha1, NULL);
 281         }
 282         strbuf_release(&rev);
 283 }
 284
 285 /*
 286  * Determine if a submodule has been initialized at a given 'path'
 287  */
 288 int is_submodule_active(struct repository *repo, const char *path)
 289 {
 290         int ret = 0;
 291         char *key = NULL;
 292         char *value = NULL;
 293         const struct string_list *sl;
 294         const struct submodule *module;
 295
 296         module = submodule_from_cache(repo, null_sha1, path);
 297
 298         /* early return if there isn't a path->module mapping */
 299         if (!module)
 300                 return 0;
 301
 302         /* submodule.<name>.active is set */
 303         key = xstrfmt("submodule.%s.active", module->name);
 304         if (!repo_config_get_bool(repo, key, &ret)) {
 305                 free(key);
 306                 return ret;
 307         }
 308         free(key);
 309
 310         /* submodule.active is set */
 311         sl = repo_config_get_value_multi(repo, "submodule.active");
 312         if (sl) {
 313                 struct pathspec ps;
 314                 struct argv_array args = ARGV_ARRAY_INIT;
 315                 const struct string_list_item *item;
 316
 317                 for_each_string_list_item(item, sl) {
 318                         argv_array_push(&args, item->string);
 319                 }
 320
 321                 parse_pathspec(&ps, 0, 0, NULL, args.argv);
 322                 ret = match_pathspec(&ps, path, strlen(path), 0, NULL, 1);
 323
 324                 argv_array_clear(&args);
 325                 clear_pathspec(&ps);
 326                 return ret;
 327         }
 328
 329         /* fallback to checking if the URL is set */
 330         key = xstrfmt("submodule.%s.url", module->name);
 331         ret = !repo_config_get_string(repo, key, &value);
 332
 333         free(value);
 334         free(key);
 335         return ret;
 336 }
 337
 338 int is_submodule_populated_gently(const char *path, int *return_error_code)
 339 {
 340         int ret = 0;
 341         char *gitdir = xstrfmt("%s/.git", path);
 342
 343         if (resolve_gitdir_gently(gitdir, return_error_code))
 344                 ret = 1;
 345
 346         free(gitdir);
 347         return ret;
 348 }
 349
 350 /*
 351  * Dies if the provided 'prefix' corresponds to an unpopulated submodule
 352  */
 353 void die_in_unpopulated_submodule(const struct index_state *istate,
 354                                   const char *prefix)
 355 {
 356         int i, prefixlen;
 357
 358         if (!prefix)
 359                 return;
 360
 361         prefixlen = strlen(prefix);
 362
 363         for (i = 0; i < istate->cache_nr; i++) {
 364                 struct cache_entry *ce = istate->cache[i];
 365                 int ce_len = ce_namelen(ce);
 366
 367                 if (!S_ISGITLINK(ce->ce_mode))
 368                         continue;
 369                 if (prefixlen <= ce_len)
 370                         continue;
 371                 if (strncmp(ce->name, prefix, ce_len))
 372                         continue;
 373                 if (prefix[ce_len] != '/')
 374                         continue;
 375
 376                 die(_("in unpopulated submodule '%s'"), ce->name);
 377         }
 378 }
 379
 380 /*
 381  * Dies if any paths in the provided pathspec descends into a submodule
 382  */
 383 void die_path_inside_submodule(const struct index_state *istate,
 384                                const struct pathspec *ps)
 385 {
 386         int i, j;
 387
 388         for (i = 0; i < istate->cache_nr; i++) {
 389                 struct cache_entry *ce = istate->cache[i];
 390                 int ce_len = ce_namelen(ce);
 391
 392                 if (!S_ISGITLINK(ce->ce_mode))
 393                         continue;
 394
 395                 for (j = 0; j < ps->nr ; j++) {
 396                         const struct pathspec_item *item = &ps->items[j];
 397
 398                         if (item->len <= ce_len)
 399                                 continue;
 400                         if (item->match[ce_len] != '/')
 401                                 continue;
 402                         if (strncmp(ce->name, item->match, ce_len))
 403                                 continue;
 404                         if (item->len == ce_len + 1)
 405                                 continue;
 406
 407                         die(_("Pathspec '%s' is in submodule '%.*s'"),
 408                             item->original, ce_len, ce->name);
 409                 }
 410         }
 411 }
 412
 413 int parse_submodule_update_strategy(const char *value,
 414                 struct submodule_update_strategy *dst)
 415 {
 416         free((void*)dst->command);
 417         dst->command = NULL;
 418         if (!strcmp(value, "none"))
 419                 dst->type = SM_UPDATE_NONE;
 420         else if (!strcmp(value, "checkout"))
 421                 dst->type = SM_UPDATE_CHECKOUT;
 422         else if (!strcmp(value, "rebase"))
 423                 dst->type = SM_UPDATE_REBASE;
 424         else if (!strcmp(value, "merge"))
 425                 dst->type = SM_UPDATE_MERGE;
 426         else if (skip_prefix(value, "!", &value)) {
 427                 dst->type = SM_UPDATE_COMMAND;
 428                 dst->command = xstrdup(value);
 429         } else
 430                 return -1;
 431         return 0;
 432 }
 433
 434 const char *submodule_strategy_to_string(const struct submodule_update_strategy *s)
 435 {
 436         struct strbuf sb = STRBUF_INIT;
 437         switch (s->type) {
 438         case SM_UPDATE_CHECKOUT:
 439                 return "checkout";
 440         case SM_UPDATE_MERGE:
 441                 return "merge";
 442         case SM_UPDATE_REBASE:
 443                 return "rebase";
 444         case SM_UPDATE_NONE:
 445                 return "none";
 446         case SM_UPDATE_UNSPECIFIED:
 447                 return NULL;
 448         case SM_UPDATE_COMMAND:
 449                 strbuf_addf(&sb, "!%s", s->command);
 450                 return strbuf_detach(&sb, NULL);
 451         }
 452         return NULL;
 453 }
 454
 455 void handle_ignore_submodules_arg(struct diff_options *diffopt,
 456                                   const char *arg)
 457 {
 458         DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
 459         DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 460         DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
 461
 462         if (!strcmp(arg, "all"))
 463                 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
 464         else if (!strcmp(arg, "untracked"))
 465                 DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
 466         else if (!strcmp(arg, "dirty"))
 467                 DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
 468         else if (strcmp(arg, "none"))
 469                 die("bad --ignore-submodules argument: %s", arg);
 470 }
 471
 472 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
 473                 struct commit *left, struct commit *right,
 474                 struct commit_list *merge_bases)
 475 {
 476         struct commit_list *list;
 477
 478         init_revisions(rev, NULL);
 479         setup_revisions(0, NULL, rev, NULL);
 480         rev->left_right = 1;
 481         rev->first_parent_only = 1;
 482         left->object.flags |= SYMMETRIC_LEFT;
 483         add_pending_object(rev, &left->object, path);
 484         add_pending_object(rev, &right->object, path);
 485         for (list = merge_bases; list; list = list->next) {
 486                 list->item->object.flags |= UNINTERESTING;
 487                 add_pending_object(rev, &list->item->object,
 488                         oid_to_hex(&list->item->object.oid));
 489         }
 490         return prepare_revision_walk(rev);
 491 }
 492
 493 static void print_submodule_summary(struct rev_info *rev, struct diff_options *o)
 494 {
 495         static const char format[] = "  %m %s";
 496         struct strbuf sb = STRBUF_INIT;
 497         struct commit *commit;
 498
 499         while ((commit = get_revision(rev))) {
 500                 struct pretty_print_context ctx = {0};
 501                 ctx.date_mode = rev->date_mode;
 502                 ctx.output_encoding = get_log_output_encoding();
 503                 strbuf_setlen(&sb, 0);
 504                 format_commit_message(commit, format, &sb, &ctx);
 505                 strbuf_addch(&sb, '\n');
 506                 if (commit->object.flags & SYMMETRIC_LEFT)
 507                         diff_emit_submodule_del(o, sb.buf);
 508                 else
 509                         diff_emit_submodule_add(o, sb.buf);
 510         }
 511         strbuf_release(&sb);
 512 }
 513
 514 static void prepare_submodule_repo_env_no_git_dir(struct argv_array *out)
 515 {
 516         const char * const *var;
 517
 518         for (var = local_repo_env; *var; var++) {
 519                 if (strcmp(*var, CONFIG_DATA_ENVIRONMENT))
 520                         argv_array_push(out, *var);
 521         }
 522 }
 523
 524 void prepare_submodule_repo_env(struct argv_array *out)
 525 {
 526         prepare_submodule_repo_env_no_git_dir(out);
 527         argv_array_pushf(out, "%s=%s", GIT_DIR_ENVIRONMENT,
 528                          DEFAULT_GIT_DIR_ENVIRONMENT);
 529 }
 530
 531 /* Helper function to display the submodule header line prior to the full
 532  * summary output. If it can locate the submodule objects directory it will
 533  * attempt to lookup both the left and right commits and put them into the
 534  * left and right pointers.
 535  */
 536 static void show_submodule_header(struct diff_options *o, const char *path,
 537                 struct object_id *one, struct object_id *two,
 538                 unsigned dirty_submodule,
 539                 struct commit **left, struct commit **right,
 540                 struct commit_list **merge_bases)
 541 {
 542         const char *message = NULL;
 543         struct strbuf sb = STRBUF_INIT;
 544         int fast_forward = 0, fast_backward = 0;
 545
 546         if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
 547                 diff_emit_submodule_untracked(o, path);
 548
 549         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
 550                 diff_emit_submodule_modified(o, path);
 551
 552         if (is_null_oid(one))
 553                 message = "(new submodule)";
 554         else if (is_null_oid(two))
 555                 message = "(submodule deleted)";
 556
 557         if (add_submodule_odb(path)) {
 558                 if (!message)
 559                         message = "(not initialized)";
 560                 goto output_header;
 561         }
 562
 563         /*
 564          * Attempt to lookup the commit references, and determine if this is
 565          * a fast forward or fast backwards update.
 566          */
 567         *left = lookup_commit_reference(one);
 568         *right = lookup_commit_reference(two);
 569
 570         /*
 571          * Warn about missing commits in the submodule project, but only if
 572          * they aren't null.
 573          */
 574         if ((!is_null_oid(one) && !*left) ||
 575              (!is_null_oid(two) && !*right))
 576                 message = "(commits not present)";
 577
 578         *merge_bases = get_merge_bases(*left, *right);
 579         if (*merge_bases) {
 580                 if ((*merge_bases)->item == *left)
 581                         fast_forward = 1;
 582                 else if ((*merge_bases)->item == *right)
 583                         fast_backward = 1;
 584         }
 585
 586         if (!oidcmp(one, two)) {
 587                 strbuf_release(&sb);
 588                 return;
 589         }
 590
 591 output_header:
 592         strbuf_addf(&sb, "Submodule %s ", path);
 593         strbuf_add_unique_abbrev(&sb, one->hash, DEFAULT_ABBREV);
 594         strbuf_addstr(&sb, (fast_backward || fast_forward) ? ".." : "...");
 595         strbuf_add_unique_abbrev(&sb, two->hash, DEFAULT_ABBREV);
 596         if (message)
 597                 strbuf_addf(&sb, " %s\n", message);
 598         else
 599                 strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
 600         diff_emit_submodule_header(o, sb.buf);
 601
 602         strbuf_release(&sb);
 603 }
 604
 605 void show_submodule_summary(struct diff_options *o, const char *path,
 606                 struct object_id *one, struct object_id *two,
 607                 unsigned dirty_submodule)
 608 {
 609         struct rev_info rev;
 610         struct commit *left = NULL, *right = NULL;
 611         struct commit_list *merge_bases = NULL;
 612
 613         show_submodule_header(o, path, one, two, dirty_submodule,
 614                               &left, &right, &merge_bases);
 615
 616         /*
 617          * If we don't have both a left and a right pointer, there is no
 618          * reason to try and display a summary. The header line should contain
 619          * all the information the user needs.
 620          */
 621         if (!left || !right)
 622                 goto out;
 623
 624         /* Treat revision walker failure the same as missing commits */
 625         if (prepare_submodule_summary(&rev, path, left, right, merge_bases)) {
 626                 diff_emit_submodule_error(o, "(revision walker failed)\n");
 627                 goto out;
 628         }
 629
 630         print_submodule_summary(&rev, o);
 631
 632 out:
 633         if (merge_bases)
 634                 free_commit_list(merge_bases);
 635         clear_commit_marks(left, ~0);
 636         clear_commit_marks(right, ~0);
 637 }
 638
 639 void show_submodule_inline_diff(struct diff_options *o, const char *path,
 640                 struct object_id *one, struct object_id *two,
 641                 unsigned dirty_submodule)
 642 {
 643         const struct object_id *old = &empty_tree_oid, *new = &empty_tree_oid;
 644         struct commit *left = NULL, *right = NULL;
 645         struct commit_list *merge_bases = NULL;
 646         struct child_process cp = CHILD_PROCESS_INIT;
 647         struct strbuf sb = STRBUF_INIT;
 648
 649         show_submodule_header(o, path, one, two, dirty_submodule,
 650                               &left, &right, &merge_bases);
 651
 652         /* We need a valid left and right commit to display a difference */
 653         if (!(left || is_null_oid(one)) ||
 654             !(right || is_null_oid(two)))
 655                 goto done;
 656
 657         if (left)
 658                 old = one;
 659         if (right)
 660                 new = two;
 661
 662         cp.git_cmd = 1;
 663         cp.dir = path;
 664         cp.out = -1;
 665         cp.no_stdin = 1;
 666
 667         /* TODO: other options may need to be passed here. */
 668         argv_array_pushl(&cp.args, "diff", "--submodule=diff", NULL);
 669         argv_array_pushf(&cp.args, "--color=%s", want_color(o->use_color) ?
 670                          "always" : "never");
 671
 672         if (DIFF_OPT_TST(o, REVERSE_DIFF)) {
 673                 argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 674                                  o->b_prefix, path);
 675                 argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
 676                                  o->a_prefix, path);
 677         } else {
 678                 argv_array_pushf(&cp.args, "--src-prefix=%s%s/",
 679                                  o->a_prefix, path);
 680                 argv_array_pushf(&cp.args, "--dst-prefix=%s%s/",
 681                                  o->b_prefix, path);
 682         }
 683         argv_array_push(&cp.args, oid_to_hex(old));
 684         /*
 685          * If the submodule has modified content, we will diff against the
 686          * work tree, under the assumption that the user has asked for the
 687          * diff format and wishes to actually see all differences even if they
 688          * haven't yet been committed to the submodule yet.
 689          */
 690         if (!(dirty_submodule & DIRTY_SUBMODULE_MODIFIED))
 691                 argv_array_push(&cp.args, oid_to_hex(new));
 692
 693         prepare_submodule_repo_env(&cp.env_array);
 694         if (start_command(&cp))
 695                 diff_emit_submodule_error(o, "(diff failed)\n");
 696
 697         while (strbuf_getwholeline_fd(&sb, cp.out, '\n') != EOF)
 698                 diff_emit_submodule_pipethrough(o, sb.buf, sb.len);
 699
 700         if (finish_command(&cp))
 701                 diff_emit_submodule_error(o, "(diff failed)\n");
 702
 703 done:
 704         strbuf_release(&sb);
 705         if (merge_bases)
 706                 free_commit_list(merge_bases);
 707         if (left)
 708                 clear_commit_marks(left, ~0);
 709         if (right)
 710                 clear_commit_marks(right, ~0);
 711 }
 712
 713 void set_config_fetch_recurse_submodules(int value)
 714 {
 715         config_fetch_recurse_submodules = value;
 716 }
 717
 718 int should_update_submodules(void)
 719 {
 720         return config_update_recurse_submodules == RECURSE_SUBMODULES_ON;
 721 }
 722
 723 const struct submodule *submodule_from_ce(const struct cache_entry *ce)
 724 {
 725         if (!S_ISGITLINK(ce->ce_mode))
 726                 return NULL;
 727
 728         if (!should_update_submodules())
 729                 return NULL;
 730
 731         return submodule_from_path(null_sha1, ce->name);
 732 }
 733
 734 static struct oid_array *submodule_commits(struct string_list *submodules,
 735                                            const char *path)
 736 {
 737         struct string_list_item *item;
 738
 739         item = string_list_insert(submodules, path);
 740         if (item->util)
 741                 return (struct oid_array *) item->util;
 742
 743         /* NEEDSWORK: should we have oid_array_init()? */
 744         item->util = xcalloc(1, sizeof(struct oid_array));
 745         return (struct oid_array *) item->util;
 746 }
 747
 748 static void collect_changed_submodules_cb(struct diff_queue_struct *q,
 749                                           struct diff_options *options,
 750                                           void *data)
 751 {
 752         int i;
 753         struct string_list *changed = data;
 754
 755         for (i = 0; i < q->nr; i++) {
 756                 struct diff_filepair *p = q->queue[i];
 757                 struct oid_array *commits;
 758                 if (!S_ISGITLINK(p->two->mode))
 759                         continue;
 760
 761                 if (S_ISGITLINK(p->one->mode)) {
 762                         /*
 763                          * NEEDSWORK: We should honor the name configured in
 764                          * the .gitmodules file of the commit we are examining
 765                          * here to be able to correctly follow submodules
 766                          * being moved around.
 767                          */
 768                         commits = submodule_commits(changed, p->two->path);
 769                         oid_array_append(commits, &p->two->oid);
 770                 } else {
 771                         /* Submodule is new or was moved here */
 772                         /*
 773                          * NEEDSWORK: When the .git directories of submodules
 774                          * live inside the superprojects .git directory some
 775                          * day we should fetch new submodules directly into
 776                          * that location too when config or options request
 777                          * that so they can be checked out from there.
 778                          */
 779                         continue;
 780                 }
 781         }
 782 }
 783
 784 /*
 785  * Collect the paths of submodules in 'changed' which have changed based on
 786  * the revisions as specified in 'argv'.  Each entry in 'changed' will also
 787  * have a corresponding 'struct oid_array' (in the 'util' field) which lists
 788  * what the submodule pointers were updated to during the change.
 789  */
 790 static void collect_changed_submodules(struct string_list *changed,
 791                                        struct argv_array *argv)
 792 {
 793         struct rev_info rev;
 794         const struct commit *commit;
 795
 796         init_revisions(&rev, NULL);
 797         setup_revisions(argv->argc, argv->argv, &rev, NULL);
 798         if (prepare_revision_walk(&rev))
 799                 die("revision walk setup failed");
 800
 801         while ((commit = get_revision(&rev))) {
 802                 struct rev_info diff_rev;
 803
 804                 init_revisions(&diff_rev, NULL);
 805                 diff_rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
 806                 diff_rev.diffopt.format_callback = collect_changed_submodules_cb;
 807                 diff_rev.diffopt.format_callback_data = changed;
 808                 diff_tree_combined_merge(commit, 1, &diff_rev);
 809         }
 810
 811         reset_revision_walk();
 812 }
 813
 814 static void free_submodules_oids(struct string_list *submodules)
 815 {
 816         struct string_list_item *item;
 817         for_each_string_list_item(item, submodules)
 818                 oid_array_clear((struct oid_array *) item->util);
 819         string_list_clear(submodules, 1);
 820 }
 821
 822 static int has_remote(const char *refname, const struct object_id *oid,
 823                       int flags, void *cb_data)
 824 {
 825         return 1;
 826 }
 827
 828 static int append_oid_to_argv(const struct object_id *oid, void *data)
 829 {
 830         struct argv_array *argv = data;
 831         argv_array_push(argv, oid_to_hex(oid));
 832         return 0;
 833 }
 834
 835 static int check_has_commit(const struct object_id *oid, void *data)
 836 {
 837         int *has_commit = data;
 838
 839         if (!lookup_commit_reference(oid))
 840                 *has_commit = 0;
 841
 842         return 0;
 843 }
 844
 845 static int submodule_has_commits(const char *path, struct oid_array *commits)
 846 {
 847         int has_commit = 1;
 848
 849         /*
 850          * Perform a cheap, but incorrect check for the existence of 'commits'.
 851          * This is done by adding the submodule's object store to the in-core
 852          * object store, and then querying for each commit's existence.  If we
 853          * do not have the commit object anywhere, there is no chance we have
 854          * it in the object store of the correct submodule and have it
 855          * reachable from a ref, so we can fail early without spawning rev-list
 856          * which is expensive.
 857          */
 858         if (add_submodule_odb(path))
 859                 return 0;
 860
 861         oid_array_for_each_unique(commits, check_has_commit, &has_commit);
 862
 863         if (has_commit) {
 864                 /*
 865                  * Even if the submodule is checked out and the commit is
 866                  * present, make sure it exists in the submodule's object store
 867                  * and that it is reachable from a ref.
 868                  */
 869                 struct child_process cp = CHILD_PROCESS_INIT;
 870                 struct strbuf out = STRBUF_INIT;
 871
 872                 argv_array_pushl(&cp.args, "rev-list", "-n", "1", NULL);
 873                 oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
 874                 argv_array_pushl(&cp.args, "--not", "--all", NULL);
 875
 876                 prepare_submodule_repo_env(&cp.env_array);
 877                 cp.git_cmd = 1;
 878                 cp.no_stdin = 1;
 879                 cp.dir = path;
 880
 881                 if (capture_command(&cp, &out, GIT_MAX_HEXSZ + 1) || out.len)
 882                         has_commit = 0;
 883
 884                 strbuf_release(&out);
 885         }
 886
 887         return has_commit;
 888 }
 889
 890 static int submodule_needs_pushing(const char *path, struct oid_array *commits)
 891 {
 892         if (!submodule_has_commits(path, commits))
 893                 /*
 894                  * NOTE: We do consider it safe to return "no" here. The
 895                  * correct answer would be "We do not know" instead of
 896                  * "No push needed", but it is quite hard to change
 897                  * the submodule pointer without having the submodule
 898                  * around. If a user did however change the submodules
 899                  * without having the submodule around, this indicates
 900                  * an expert who knows what they are doing or a
 901                  * maintainer integrating work from other people. In
 902                  * both cases it should be safe to skip this check.
 903                  */
 904                 return 0;
 905
 906         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 907                 struct child_process cp = CHILD_PROCESS_INIT;
 908                 struct strbuf buf = STRBUF_INIT;
 909                 int needs_pushing = 0;
 910
 911                 argv_array_push(&cp.args, "rev-list");
 912                 oid_array_for_each_unique(commits, append_oid_to_argv, &cp.args);
 913                 argv_array_pushl(&cp.args, "--not", "--remotes", "-n", "1" , NULL);
 914
 915                 prepare_submodule_repo_env(&cp.env_array);
 916                 cp.git_cmd = 1;
 917                 cp.no_stdin = 1;
 918                 cp.out = -1;
 919                 cp.dir = path;
 920                 if (start_command(&cp))
 921                         die("Could not run 'git rev-list <commits> --not --remotes -n 1' command in submodule %s",
 922                                         path);
 923                 if (strbuf_read(&buf, cp.out, 41))
 924                         needs_pushing = 1;
 925                 finish_command(&cp);
 926                 close(cp.out);
 927                 strbuf_release(&buf);
 928                 return needs_pushing;
 929         }
 930
 931         return 0;
 932 }
 933
 934 int find_unpushed_submodules(struct oid_array *commits,
 935                 const char *remotes_name, struct string_list *needs_pushing)
 936 {
 937         struct string_list submodules = STRING_LIST_INIT_DUP;
 938         struct string_list_item *submodule;
 939         struct argv_array argv = ARGV_ARRAY_INIT;
 940
 941         /* argv.argv[0] will be ignored by setup_revisions */
 942         argv_array_push(&argv, "find_unpushed_submodules");
 943         oid_array_for_each_unique(commits, append_oid_to_argv, &argv);
 944         argv_array_push(&argv, "--not");
 945         argv_array_pushf(&argv, "--remotes=%s", remotes_name);
 946
 947         collect_changed_submodules(&submodules, &argv);
 948
 949         for_each_string_list_item(submodule, &submodules) {
 950                 struct oid_array *commits = submodule->util;
 951                 const char *path = submodule->string;
 952
 953                 if (submodule_needs_pushing(path, commits))
 954                         string_list_insert(needs_pushing, path);
 955         }
 956
 957         free_submodules_oids(&submodules);
 958         argv_array_clear(&argv);
 959
 960         return needs_pushing->nr;
 961 }
 962
 963 static int push_submodule(const char *path,
 964                           const struct remote *remote,
 965                           const char **refspec, int refspec_nr,
 966                           const struct string_list *push_options,
 967                           int dry_run)
 968 {
 969         if (add_submodule_odb(path))
 970                 return 1;
 971
 972         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
 973                 struct child_process cp = CHILD_PROCESS_INIT;
 974                 argv_array_push(&cp.args, "push");
 975                 if (dry_run)
 976                         argv_array_push(&cp.args, "--dry-run");
 977
 978                 if (push_options && push_options->nr) {
 979                         const struct string_list_item *item;
 980                         for_each_string_list_item(item, push_options)
 981                                 argv_array_pushf(&cp.args, "--push-option=%s",
 982                                                  item->string);
 983                 }
 984
 985                 if (remote->origin != REMOTE_UNCONFIGURED) {
 986                         int i;
 987                         argv_array_push(&cp.args, remote->name);
 988                         for (i = 0; i < refspec_nr; i++)
 989                                 argv_array_push(&cp.args, refspec[i]);
 990                 }
 991
 992                 prepare_submodule_repo_env(&cp.env_array);
 993                 cp.git_cmd = 1;
 994                 cp.no_stdin = 1;
 995                 cp.dir = path;
 996                 if (run_command(&cp))
 997                         return 0;
 998                 close(cp.out);
 999         }
1000
1001         return 1;
1002 }
1003
1004 /*
1005  * Perform a check in the submodule to see if the remote and refspec work.
1006  * Die if the submodule can't be pushed.
1007  */
1008 static void submodule_push_check(const char *path, const struct remote *remote,
1009                                  const char **refspec, int refspec_nr)
1010 {
1011         struct child_process cp = CHILD_PROCESS_INIT;
1012         int i;
1013
1014         argv_array_push(&cp.args, "submodule--helper");
1015         argv_array_push(&cp.args, "push-check");
1016         argv_array_push(&cp.args, remote->name);
1017
1018         for (i = 0; i < refspec_nr; i++)
1019                 argv_array_push(&cp.args, refspec[i]);
1020
1021         prepare_submodule_repo_env(&cp.env_array);
1022         cp.git_cmd = 1;
1023         cp.no_stdin = 1;
1024         cp.no_stdout = 1;
1025         cp.dir = path;
1026
1027         /*
1028          * Simply indicate if 'submodule--helper push-check' failed.
1029          * More detailed error information will be provided by the
1030          * child process.
1031          */
1032         if (run_command(&cp))
1033                 die("process for submodule '%s' failed", path);
1034 }
1035
1036 int push_unpushed_submodules(struct oid_array *commits,
1037                              const struct remote *remote,
1038                              const char **refspec, int refspec_nr,
1039                              const struct string_list *push_options,
1040                              int dry_run)
1041 {
1042         int i, ret = 1;
1043         struct string_list needs_pushing = STRING_LIST_INIT_DUP;
1044
1045         if (!find_unpushed_submodules(commits, remote->name, &needs_pushing))
1046                 return 1;
1047
1048         /*
1049          * Verify that the remote and refspec can be propagated to all
1050          * submodules.  This check can be skipped if the remote and refspec
1051          * won't be propagated due to the remote being unconfigured (e.g. a URL
1052          * instead of a remote name).
1053          */
1054         if (remote->origin != REMOTE_UNCONFIGURED)
1055                 for (i = 0; i < needs_pushing.nr; i++)
1056                         submodule_push_check(needs_pushing.items[i].string,
1057                                              remote, refspec, refspec_nr);
1058
1059         /* Actually push the submodules */
1060         for (i = 0; i < needs_pushing.nr; i++) {
1061                 const char *path = needs_pushing.items[i].string;
1062                 fprintf(stderr, "Pushing submodule '%s'\n", path);
1063                 if (!push_submodule(path, remote, refspec, refspec_nr,
1064                                     push_options, dry_run)) {
1065                         fprintf(stderr, "Unable to push submodule '%s'\n", path);
1066                         ret = 0;
1067                 }
1068         }
1069
1070         string_list_clear(&needs_pushing, 0);
1071
1072         return ret;
1073 }
1074
1075 static int append_oid_to_array(const char *ref, const struct object_id *oid,
1076                                int flags, void *data)
1077 {
1078         struct oid_array *array = data;
1079         oid_array_append(array, oid);
1080         return 0;
1081 }
1082
1083 void check_for_new_submodule_commits(struct object_id *oid)
1084 {
1085         if (!initialized_fetch_ref_tips) {
1086                 for_each_ref(append_oid_to_array, &ref_tips_before_fetch);
1087                 initialized_fetch_ref_tips = 1;
1088         }
1089
1090         oid_array_append(&ref_tips_after_fetch, oid);
1091 }
1092
1093 static void calculate_changed_submodule_paths(void)
1094 {
1095         struct argv_array argv = ARGV_ARRAY_INIT;
1096         struct string_list changed_submodules = STRING_LIST_INIT_DUP;
1097         const struct string_list_item *item;
1098
1099         /* No need to check if there are no submodules configured */
1100         if (!submodule_from_path(NULL, NULL))
1101                 return;
1102
1103         argv_array_push(&argv, "--"); /* argv[0] program name */
1104         oid_array_for_each_unique(&ref_tips_after_fetch,
1105                                    append_oid_to_argv, &argv);
1106         argv_array_push(&argv, "--not");
1107         oid_array_for_each_unique(&ref_tips_before_fetch,
1108                                    append_oid_to_argv, &argv);
1109
1110         /*
1111          * Collect all submodules (whether checked out or not) for which new
1112          * commits have been recorded upstream in "changed_submodule_paths".
1113          */
1114         collect_changed_submodules(&changed_submodules, &argv);
1115
1116         for_each_string_list_item(item, &changed_submodules) {
1117                 struct oid_array *commits = item->util;
1118                 const char *path = item->string;
1119
1120                 if (!submodule_has_commits(path, commits))
1121                         string_list_append(&changed_submodule_paths, path);
1122         }
1123
1124         free_submodules_oids(&changed_submodules);
1125         argv_array_clear(&argv);
1126         oid_array_clear(&ref_tips_before_fetch);
1127         oid_array_clear(&ref_tips_after_fetch);
1128         initialized_fetch_ref_tips = 0;
1129 }
1130
1131 int submodule_touches_in_range(struct object_id *excl_oid,
1132                                struct object_id *incl_oid)
1133 {
1134         struct string_list subs = STRING_LIST_INIT_DUP;
1135         struct argv_array args = ARGV_ARRAY_INIT;
1136         int ret;
1137
1138         gitmodules_config();
1139         /* No need to check if there are no submodules configured */
1140         if (!submodule_from_path(NULL, NULL))
1141                 return 0;
1142
1143         argv_array_push(&args, "--"); /* args[0] program name */
1144         argv_array_push(&args, oid_to_hex(incl_oid));
1145         argv_array_push(&args, "--not");
1146         argv_array_push(&args, oid_to_hex(excl_oid));
1147
1148         collect_changed_submodules(&subs, &args);
1149         ret = subs.nr;
1150
1151         argv_array_clear(&args);
1152
1153         free_submodules_oids(&subs);
1154         return ret;
1155 }
1156
1157 struct submodule_parallel_fetch {
1158         int count;
1159         struct argv_array args;
1160         const char *work_tree;
1161         const char *prefix;
1162         int command_line_option;
1163         int quiet;
1164         int result;
1165 };
1166 #define SPF_INIT {0, ARGV_ARRAY_INIT, NULL, NULL, 0, 0, 0}
1167
1168 static int get_next_submodule(struct child_process *cp,
1169                               struct strbuf *err, void *data, void **task_cb)
1170 {
1171         int ret = 0;
1172         struct submodule_parallel_fetch *spf = data;
1173
1174         for (; spf->count < active_nr; spf->count++) {
1175                 struct strbuf submodule_path = STRBUF_INIT;
1176                 struct strbuf submodule_git_dir = STRBUF_INIT;
1177                 struct strbuf submodule_prefix = STRBUF_INIT;
1178                 const struct cache_entry *ce = active_cache[spf->count];
1179                 const char *git_dir, *default_argv;
1180                 const struct submodule *submodule;
1181
1182                 if (!S_ISGITLINK(ce->ce_mode))
1183                         continue;
1184
1185                 submodule = submodule_from_path(null_sha1, ce->name);
1186                 if (!submodule)
1187                         submodule = submodule_from_name(null_sha1, ce->name);
1188
1189                 default_argv = "yes";
1190                 if (spf->command_line_option == RECURSE_SUBMODULES_DEFAULT) {
1191                         if (submodule &&
1192                             submodule->fetch_recurse !=
1193                                                 RECURSE_SUBMODULES_NONE) {
1194                                 if (submodule->fetch_recurse ==
1195                                                 RECURSE_SUBMODULES_OFF)
1196                                         continue;
1197                                 if (submodule->fetch_recurse ==
1198                                                 RECURSE_SUBMODULES_ON_DEMAND) {
1199                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1200                                                 continue;
1201                                         default_argv = "on-demand";
1202                                 }
1203                         } else {
1204                                 if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
1205                                     gitmodules_is_unmerged)
1206                                         continue;
1207                                 if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
1208                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1209                                                 continue;
1210                                         default_argv = "on-demand";
1211                                 }
1212                         }
1213                 } else if (spf->command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
1214                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
1215                                 continue;
1216                         default_argv = "on-demand";
1217                 }
1218
1219                 strbuf_addf(&submodule_path, "%s/%s", spf->work_tree, ce->name);
1220                 strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
1221                 strbuf_addf(&submodule_prefix, "%s%s/", spf->prefix, ce->name);
1222                 git_dir = read_gitfile(submodule_git_dir.buf);
1223                 if (!git_dir)
1224                         git_dir = submodule_git_dir.buf;
1225                 if (is_directory(git_dir)) {
1226                         child_process_init(cp);
1227                         cp->dir = strbuf_detach(&submodule_path, NULL);
1228                         prepare_submodule_repo_env(&cp->env_array);
1229                         cp->git_cmd = 1;
1230                         if (!spf->quiet)
1231                                 strbuf_addf(err, "Fetching submodule %s%s\n",
1232                                             spf->prefix, ce->name);
1233                         argv_array_init(&cp->args);
1234                         argv_array_pushv(&cp->args, spf->args.argv);
1235                         argv_array_push(&cp->args, default_argv);
1236                         argv_array_push(&cp->args, "--submodule-prefix");
1237                         argv_array_push(&cp->args, submodule_prefix.buf);
1238                         ret = 1;
1239                 }
1240                 strbuf_release(&submodule_path);
1241                 strbuf_release(&submodule_git_dir);
1242                 strbuf_release(&submodule_prefix);
1243                 if (ret) {
1244                         spf->count++;
1245                         return 1;
1246                 }
1247         }
1248         return 0;
1249 }
1250
1251 static int fetch_start_failure(struct strbuf *err,
1252                                void *cb, void *task_cb)
1253 {
1254         struct submodule_parallel_fetch *spf = cb;
1255
1256         spf->result = 1;
1257
1258         return 0;
1259 }
1260
1261 static int fetch_finish(int retvalue, struct strbuf *err,
1262                         void *cb, void *task_cb)
1263 {
1264         struct submodule_parallel_fetch *spf = cb;
1265
1266         if (retvalue)
1267                 spf->result = 1;
1268
1269         return 0;
1270 }
1271
1272 int fetch_populated_submodules(const struct argv_array *options,
1273                                const char *prefix, int command_line_option,
1274                                int quiet, int max_parallel_jobs)
1275 {
1276         int i;
1277         struct submodule_parallel_fetch spf = SPF_INIT;
1278
1279         spf.work_tree = get_git_work_tree();
1280         spf.command_line_option = command_line_option;
1281         spf.quiet = quiet;
1282         spf.prefix = prefix;
1283
1284         if (!spf.work_tree)
1285                 goto out;
1286
1287         if (read_cache() < 0)
1288                 die("index file corrupt");
1289
1290         argv_array_push(&spf.args, "fetch");
1291         for (i = 0; i < options->argc; i++)
1292                 argv_array_push(&spf.args, options->argv[i]);
1293         argv_array_push(&spf.args, "--recurse-submodules-default");
1294         /* default value, "--submodule-prefix" and its value are added later */
1295
1296         if (max_parallel_jobs < 0)
1297                 max_parallel_jobs = parallel_jobs;
1298
1299         calculate_changed_submodule_paths();
1300         run_processes_parallel(max_parallel_jobs,
1301                                get_next_submodule,
1302                                fetch_start_failure,
1303                                fetch_finish,
1304                                &spf);
1305
1306         argv_array_clear(&spf.args);
1307 out:
1308         string_list_clear(&changed_submodule_paths, 1);
1309         return spf.result;
1310 }
1311
1312 unsigned is_submodule_modified(const char *path, int ignore_untracked)
1313 {
1314         struct child_process cp = CHILD_PROCESS_INIT;
1315         struct strbuf buf = STRBUF_INIT;
1316         FILE *fp;
1317         unsigned dirty_submodule = 0;
1318         const char *git_dir;
1319         int ignore_cp_exit_code = 0;
1320
1321         strbuf_addf(&buf, "%s/.git", path);
1322         git_dir = read_gitfile(buf.buf);
1323         if (!git_dir)
1324                 git_dir = buf.buf;
1325         if (!is_git_directory(git_dir)) {
1326                 if (is_directory(git_dir))
1327                         die(_("'%s' not recognized as a git repository"), git_dir);
1328                 strbuf_release(&buf);
1329                 /* The submodule is not checked out, so it is not modified */
1330                 return 0;
1331         }
1332         strbuf_reset(&buf);
1333
1334         argv_array_pushl(&cp.args, "status", "--porcelain=2", NULL);
1335         if (ignore_untracked)
1336                 argv_array_push(&cp.args, "-uno");
1337
1338         prepare_submodule_repo_env(&cp.env_array);
1339         cp.git_cmd = 1;
1340         cp.no_stdin = 1;
1341         cp.out = -1;
1342         cp.dir = path;
1343         if (start_command(&cp))
1344                 die("Could not run 'git status --porcelain=2' in submodule %s", path);
1345
1346         fp = xfdopen(cp.out, "r");
1347         while (strbuf_getwholeline(&buf, fp, '\n') != EOF) {
1348                 /* regular untracked files */
1349                 if (buf.buf[0] == '?')
1350                         dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
1351
1352                 if (buf.buf[0] == 'u' ||
1353                     buf.buf[0] == '1' ||
1354                     buf.buf[0] == '2') {
1355                         /* T = line type, XY = status, SSSS = submodule state */
1356                         if (buf.len < strlen("T XY SSSS"))
1357                                 die("BUG: invalid status --porcelain=2 line %s",
1358                                     buf.buf);
1359
1360                         if (buf.buf[5] == 'S' && buf.buf[8] == 'U')
1361                                 /* nested untracked file */
1362                                 dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
1363
1364                         if (buf.buf[0] == 'u' ||
1365                             buf.buf[0] == '2' ||
1366                             memcmp(buf.buf + 5, "S..U", 4))
1367                                 /* other change */
1368                                 dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
1369                 }
1370
1371                 if ((dirty_submodule & DIRTY_SUBMODULE_MODIFIED) &&
1372                     ((dirty_submodule & DIRTY_SUBMODULE_UNTRACKED) ||
1373                      ignore_untracked)) {
1374                         /*
1375                          * We're not interested in any further information from
1376                          * the child any more, neither output nor its exit code.
1377                          */
1378                         ignore_cp_exit_code = 1;
1379                         break;
1380                 }
1381         }
1382         fclose(fp);
1383
1384         if (finish_command(&cp) && !ignore_cp_exit_code)
1385                 die("'git status --porcelain=2' failed in submodule %s", path);
1386
1387         strbuf_release(&buf);
1388         return dirty_submodule;
1389 }
1390
1391 int submodule_uses_gitfile(const char *path)
1392 {
1393         struct child_process cp = CHILD_PROCESS_INIT;
1394         const char *argv[] = {
1395                 "submodule",
1396                 "foreach",
1397                 "--quiet",
1398                 "--recursive",
1399                 "test -f .git",
1400                 NULL,
1401         };
1402         struct strbuf buf = STRBUF_INIT;
1403         const char *git_dir;
1404
1405         strbuf_addf(&buf, "%s/.git", path);
1406         git_dir = read_gitfile(buf.buf);
1407         if (!git_dir) {
1408                 strbuf_release(&buf);
1409                 return 0;
1410         }
1411         strbuf_release(&buf);
1412
1413         /* Now test that all nested submodules use a gitfile too */
1414         cp.argv = argv;
1415         prepare_submodule_repo_env(&cp.env_array);
1416         cp.git_cmd = 1;
1417         cp.no_stdin = 1;
1418         cp.no_stderr = 1;
1419         cp.no_stdout = 1;
1420         cp.dir = path;
1421         if (run_command(&cp))
1422                 return 0;
1423
1424         return 1;
1425 }
1426
1427 /*
1428  * Check if it is a bad idea to remove a submodule, i.e. if we'd lose data
1429  * when doing so.
1430  *
1431  * Return 1 if we'd lose data, return 0 if the removal is fine,
1432  * and negative values for errors.
1433  */
1434 int bad_to_remove_submodule(const char *path, unsigned flags)
1435 {
1436         ssize_t len;
1437         struct child_process cp = CHILD_PROCESS_INIT;
1438         struct strbuf buf = STRBUF_INIT;
1439         int ret = 0;
1440
1441         if (!file_exists(path) || is_empty_dir(path))
1442                 return 0;
1443
1444         if (!submodule_uses_gitfile(path))
1445                 return 1;
1446
1447         argv_array_pushl(&cp.args, "status", "--porcelain",
1448                                    "--ignore-submodules=none", NULL);
1449
1450         if (flags & SUBMODULE_REMOVAL_IGNORE_UNTRACKED)
1451                 argv_array_push(&cp.args, "-uno");
1452         else
1453                 argv_array_push(&cp.args, "-uall");
1454
1455         if (!(flags & SUBMODULE_REMOVAL_IGNORE_IGNORED_UNTRACKED))
1456                 argv_array_push(&cp.args, "--ignored");
1457
1458         prepare_submodule_repo_env(&cp.env_array);
1459         cp.git_cmd = 1;
1460         cp.no_stdin = 1;
1461         cp.out = -1;
1462         cp.dir = path;
1463         if (start_command(&cp)) {
1464                 if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
1465                         die(_("could not start 'git status' in submodule '%s'"),
1466                                 path);
1467                 ret = -1;
1468                 goto out;
1469         }
1470
1471         len = strbuf_read(&buf, cp.out, 1024);
1472         if (len > 2)
1473                 ret = 1;
1474         close(cp.out);
1475
1476         if (finish_command(&cp)) {
1477                 if (flags & SUBMODULE_REMOVAL_DIE_ON_ERROR)
1478                         die(_("could not run 'git status' in submodule '%s'"),
1479                                 path);
1480                 ret = -1;
1481         }
1482 out:
1483         strbuf_release(&buf);
1484         return ret;
1485 }
1486
1487 static const char *get_super_prefix_or_empty(void)
1488 {
1489         const char *s = get_super_prefix();
1490         if (!s)
1491                 s = "";
1492         return s;
1493 }
1494
1495 static int submodule_has_dirty_index(const struct submodule *sub)
1496 {
1497         struct child_process cp = CHILD_PROCESS_INIT;
1498
1499         prepare_submodule_repo_env(&cp.env_array);
1500
1501         cp.git_cmd = 1;
1502         argv_array_pushl(&cp.args, "diff-index", "--quiet",
1503                                    "--cached", "HEAD", NULL);
1504         cp.no_stdin = 1;
1505         cp.no_stdout = 1;
1506         cp.dir = sub->path;
1507         if (start_command(&cp))
1508                 die("could not recurse into submodule '%s'", sub->path);
1509
1510         return finish_command(&cp);
1511 }
1512
1513 static void submodule_reset_index(const char *path)
1514 {
1515         struct child_process cp = CHILD_PROCESS_INIT;
1516         prepare_submodule_repo_env(&cp.env_array);
1517
1518         cp.git_cmd = 1;
1519         cp.no_stdin = 1;
1520         cp.dir = path;
1521
1522         argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
1523                                    get_super_prefix_or_empty(), path);
1524         argv_array_pushl(&cp.args, "read-tree", "-u", "--reset", NULL);
1525
1526         argv_array_push(&cp.args, EMPTY_TREE_SHA1_HEX);
1527
1528         if (run_command(&cp))
1529                 die("could not reset submodule index");
1530 }
1531
1532 /**
1533  * Moves a submodule at a given path from a given head to another new head.
1534  * For edge cases (a submodule coming into existence or removing a submodule)
1535  * pass NULL for old or new respectively.
1536  */
1537 int submodule_move_head(const char *path,
1538                          const char *old,
1539                          const char *new,
1540                          unsigned flags)
1541 {
1542         int ret = 0;
1543         struct child_process cp = CHILD_PROCESS_INIT;
1544         const struct submodule *sub;
1545         int *error_code_ptr, error_code;
1546
1547         if (!is_submodule_active(the_repository, path))
1548                 return 0;
1549
1550         if (flags & SUBMODULE_MOVE_HEAD_FORCE)
1551                 /*
1552                  * Pass non NULL pointer to is_submodule_populated_gently
1553                  * to prevent die()-ing. We'll use connect_work_tree_and_git_dir
1554                  * to fixup the submodule in the force case later.
1555                  */
1556                 error_code_ptr = &error_code;
1557         else
1558                 error_code_ptr = NULL;
1559
1560         if (old && !is_submodule_populated_gently(path, error_code_ptr))
1561                 return 0;
1562
1563         sub = submodule_from_path(null_sha1, path);
1564
1565         if (!sub)
1566                 die("BUG: could not get submodule information for '%s'", path);
1567
1568         if (old && !(flags & SUBMODULE_MOVE_HEAD_FORCE)) {
1569                 /* Check if the submodule has a dirty index. */
1570                 if (submodule_has_dirty_index(sub))
1571                         return error(_("submodule '%s' has dirty index"), path);
1572         }
1573
1574         if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
1575                 if (old) {
1576                         if (!submodule_uses_gitfile(path))
1577                                 absorb_git_dir_into_superproject("", path,
1578                                         ABSORB_GITDIR_RECURSE_SUBMODULES);
1579                 } else {
1580                         char *gitdir = xstrfmt("%s/modules/%s",
1581                                     get_git_common_dir(), sub->name);
1582                         connect_work_tree_and_git_dir(path, gitdir);
1583                         free(gitdir);
1584
1585                         /* make sure the index is clean as well */
1586                         submodule_reset_index(path);
1587                 }
1588
1589                 if (old && (flags & SUBMODULE_MOVE_HEAD_FORCE)) {
1590                         char *gitdir = xstrfmt("%s/modules/%s",
1591                                     get_git_common_dir(), sub->name);
1592                         connect_work_tree_and_git_dir(path, gitdir);
1593                         free(gitdir);
1594                 }
1595         }
1596
1597         prepare_submodule_repo_env(&cp.env_array);
1598
1599         cp.git_cmd = 1;
1600         cp.no_stdin = 1;
1601         cp.dir = path;
1602
1603         argv_array_pushf(&cp.args, "--super-prefix=%s%s/",
1604                         get_super_prefix_or_empty(), path);
1605         argv_array_pushl(&cp.args, "read-tree", "--recurse-submodules", NULL);
1606
1607         if (flags & SUBMODULE_MOVE_HEAD_DRY_RUN)
1608                 argv_array_push(&cp.args, "-n");
1609         else
1610                 argv_array_push(&cp.args, "-u");
1611
1612         if (flags & SUBMODULE_MOVE_HEAD_FORCE)
1613                 argv_array_push(&cp.args, "--reset");
1614         else
1615                 argv_array_push(&cp.args, "-m");
1616
1617         argv_array_push(&cp.args, old ? old : EMPTY_TREE_SHA1_HEX);
1618         argv_array_push(&cp.args, new ? new : EMPTY_TREE_SHA1_HEX);
1619
1620         if (run_command(&cp)) {
1621                 ret = -1;
1622                 goto out;
1623         }
1624
1625         if (!(flags & SUBMODULE_MOVE_HEAD_DRY_RUN)) {
1626                 if (new) {
1627                         child_process_init(&cp);
1628                         /* also set the HEAD accordingly */
1629                         cp.git_cmd = 1;
1630                         cp.no_stdin = 1;
1631                         cp.dir = path;
1632
1633                         prepare_submodule_repo_env(&cp.env_array);
1634                         argv_array_pushl(&cp.args, "update-ref", "HEAD", new, NULL);
1635
1636                         if (run_command(&cp)) {
1637                                 ret = -1;
1638                                 goto out;
1639                         }
1640                 } else {
1641                         struct strbuf sb = STRBUF_INIT;
1642
1643                         strbuf_addf(&sb, "%s/.git", path);
1644                         unlink_or_warn(sb.buf);
1645                         strbuf_release(&sb);
1646
1647                         if (is_empty_dir(path))
1648                                 rmdir_or_warn(path);
1649                 }
1650         }
1651 out:
1652         return ret;
1653 }
1654
1655 static int find_first_merges(struct object_array *result, const char *path,
1656                 struct commit *a, struct commit *b)
1657 {
1658         int i, j;
1659         struct object_array merges = OBJECT_ARRAY_INIT;
1660         struct commit *commit;
1661         int contains_another;
1662
1663         char merged_revision[42];
1664         const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
1665                                    "--all", merged_revision, NULL };
1666         struct rev_info revs;
1667         struct setup_revision_opt rev_opts;
1668
1669         memset(result, 0, sizeof(struct object_array));
1670         memset(&rev_opts, 0, sizeof(rev_opts));
1671
1672         /* get all revisions that merge commit a */
1673         xsnprintf(merged_revision, sizeof(merged_revision), "^%s",
1674                         oid_to_hex(&a->object.oid));
1675         init_revisions(&revs, NULL);
1676         rev_opts.submodule = path;
1677         setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
1678
1679         /* save all revisions from the above list that contain b */
1680         if (prepare_revision_walk(&revs))
1681                 die("revision walk setup failed");
1682         while ((commit = get_revision(&revs)) != NULL) {
1683                 struct object *o = &(commit->object);
1684                 if (in_merge_bases(b, commit))
1685                         add_object_array(o, NULL, &merges);
1686         }
1687         reset_revision_walk();
1688
1689         /* Now we've got all merges that contain a and b. Prune all
1690          * merges that contain another found merge and save them in
1691          * result.
1692          */
1693         for (i = 0; i < merges.nr; i++) {
1694                 struct commit *m1 = (struct commit *) merges.objects[i].item;
1695
1696                 contains_another = 0;
1697                 for (j = 0; j < merges.nr; j++) {
1698                         struct commit *m2 = (struct commit *) merges.objects[j].item;
1699                         if (i != j && in_merge_bases(m2, m1)) {
1700                                 contains_another = 1;
1701                                 break;
1702                         }
1703                 }
1704
1705                 if (!contains_another)
1706                         add_object_array(merges.objects[i].item, NULL, result);
1707         }
1708
1709         free(merges.objects);
1710         return result->nr;
1711 }
1712
1713 static void print_commit(struct commit *commit)
1714 {
1715         struct strbuf sb = STRBUF_INIT;
1716         struct pretty_print_context ctx = {0};
1717         ctx.date_mode.type = DATE_NORMAL;
1718         format_commit_message(commit, " %h: %m %s", &sb, &ctx);
1719         fprintf(stderr, "%s\n", sb.buf);
1720         strbuf_release(&sb);
1721 }
1722
1723 #define MERGE_WARNING(path, msg) \
1724         warning("Failed to merge submodule %s (%s)", path, msg);
1725
1726 int merge_submodule(struct object_id *result, const char *path,
1727                     const struct object_id *base, const struct object_id *a,
1728                     const struct object_id *b, int search)
1729 {
1730         struct commit *commit_base, *commit_a, *commit_b;
1731         int parent_count;
1732         struct object_array merges;
1733
1734         int i;
1735
1736         /* store a in result in case we fail */
1737         oidcpy(result, a);
1738
1739         /* we can not handle deletion conflicts */
1740         if (is_null_oid(base))
1741                 return 0;
1742         if (is_null_oid(a))
1743                 return 0;
1744         if (is_null_oid(b))
1745                 return 0;
1746
1747         if (add_submodule_odb(path)) {
1748                 MERGE_WARNING(path, "not checked out");
1749                 return 0;
1750         }
1751
1752         if (!(commit_base = lookup_commit_reference(base)) ||
1753             !(commit_a = lookup_commit_reference(a)) ||
1754             !(commit_b = lookup_commit_reference(b))) {
1755                 MERGE_WARNING(path, "commits not present");
1756                 return 0;
1757         }
1758
1759         /* check whether both changes are forward */
1760         if (!in_merge_bases(commit_base, commit_a) ||
1761             !in_merge_bases(commit_base, commit_b)) {
1762                 MERGE_WARNING(path, "commits don't follow merge-base");
1763                 return 0;
1764         }
1765
1766         /* Case #1: a is contained in b or vice versa */
1767         if (in_merge_bases(commit_a, commit_b)) {
1768                 oidcpy(result, b);
1769                 return 1;
1770         }
1771         if (in_merge_bases(commit_b, commit_a)) {
1772                 oidcpy(result, a);
1773                 return 1;
1774         }
1775
1776         /*
1777          * Case #2: There are one or more merges that contain a and b in
1778          * the submodule. If there is only one, then present it as a
1779          * suggestion to the user, but leave it marked unmerged so the
1780          * user needs to confirm the resolution.
1781          */
1782
1783         /* Skip the search if makes no sense to the calling context.  */
1784         if (!search)
1785                 return 0;
1786
1787         /* find commit which merges them */
1788         parent_count = find_first_merges(&merges, path, commit_a, commit_b);
1789         switch (parent_count) {
1790         case 0:
1791                 MERGE_WARNING(path, "merge following commits not found");
1792                 break;
1793
1794         case 1:
1795                 MERGE_WARNING(path, "not fast-forward");
1796                 fprintf(stderr, "Found a possible merge resolution "
1797                                 "for the submodule:\n");
1798                 print_commit((struct commit *) merges.objects[0].item);
1799                 fprintf(stderr,
1800                         "If this is correct simply add it to the index "
1801                         "for example\n"
1802                         "by using:\n\n"
1803                         "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
1804                         "which will accept this suggestion.\n",
1805                         oid_to_hex(&merges.objects[0].item->oid), path);
1806                 break;
1807
1808         default:
1809                 MERGE_WARNING(path, "multiple merges found");
1810                 for (i = 0; i < merges.nr; i++)
1811                         print_commit((struct commit *) merges.objects[i].item);
1812         }
1813
1814         free(merges.objects);
1815         return 0;
1816 }
1817
1818 int parallel_submodules(void)
1819 {
1820         return parallel_jobs;
1821 }
1822
1823 /*
1824  * Embeds a single submodules git directory into the superprojects git dir,
1825  * non recursively.
1826  */
1827 static void relocate_single_git_dir_into_superproject(const char *prefix,
1828                                                       const char *path)
1829 {
1830         char *old_git_dir = NULL, *real_old_git_dir = NULL, *real_new_git_dir = NULL;
1831         const char *new_git_dir;
1832         const struct submodule *sub;
1833
1834         if (submodule_uses_worktrees(path))
1835                 die(_("relocate_gitdir for submodule '%s' with "
1836                       "more than one worktree not supported"), path);
1837
1838         old_git_dir = xstrfmt("%s/.git", path);
1839         if (read_gitfile(old_git_dir))
1840                 /* If it is an actual gitfile, it doesn't need migration. */
1841                 return;
1842
1843         real_old_git_dir = real_pathdup(old_git_dir, 1);
1844
1845         sub = submodule_from_path(null_sha1, path);
1846         if (!sub)
1847                 die(_("could not lookup name for submodule '%s'"), path);
1848
1849         new_git_dir = git_path("modules/%s", sub->name);
1850         if (safe_create_leading_directories_const(new_git_dir) < 0)
1851                 die(_("could not create directory '%s'"), new_git_dir);
1852         real_new_git_dir = real_pathdup(new_git_dir, 1);
1853
1854         fprintf(stderr, _("Migrating git directory of '%s%s' from\n'%s' to\n'%s'\n"),
1855                 get_super_prefix_or_empty(), path,
1856                 real_old_git_dir, real_new_git_dir);
1857
1858         relocate_gitdir(path, real_old_git_dir, real_new_git_dir);
1859
1860         free(old_git_dir);
1861         free(real_old_git_dir);
1862         free(real_new_git_dir);
1863 }
1864
1865 /*
1866  * Migrate the git directory of the submodule given by path from
1867  * having its git directory within the working tree to the git dir nested
1868  * in its superprojects git dir under modules/.
1869  */
1870 void absorb_git_dir_into_superproject(const char *prefix,
1871                                       const char *path,
1872                                       unsigned flags)
1873 {
1874         int err_code;
1875         const char *sub_git_dir;
1876         struct strbuf gitdir = STRBUF_INIT;
1877         strbuf_addf(&gitdir, "%s/.git", path);
1878         sub_git_dir = resolve_gitdir_gently(gitdir.buf, &err_code);
1879
1880         /* Not populated? */
1881         if (!sub_git_dir) {
1882                 const struct submodule *sub;
1883
1884                 if (err_code == READ_GITFILE_ERR_STAT_FAILED) {
1885                         /* unpopulated as expected */
1886                         strbuf_release(&gitdir);
1887                         return;
1888                 }
1889
1890                 if (err_code != READ_GITFILE_ERR_NOT_A_REPO)
1891                         /* We don't know what broke here. */
1892                         read_gitfile_error_die(err_code, path, NULL);
1893
1894                 /*
1895                 * Maybe populated, but no git directory was found?
1896                 * This can happen if the superproject is a submodule
1897                 * itself and was just absorbed. The absorption of the
1898                 * superproject did not rewrite the git file links yet,
1899                 * fix it now.
1900                 */
1901                 sub = submodule_from_path(null_sha1, path);
1902                 if (!sub)
1903                         die(_("could not lookup name for submodule '%s'"), path);
1904                 connect_work_tree_and_git_dir(path,
1905                         git_path("modules/%s", sub->name));
1906         } else {
1907                 /* Is it already absorbed into the superprojects git dir? */
1908                 char *real_sub_git_dir = real_pathdup(sub_git_dir, 1);
1909                 char *real_common_git_dir = real_pathdup(get_git_common_dir(), 1);
1910
1911                 if (!starts_with(real_sub_git_dir, real_common_git_dir))
1912                         relocate_single_git_dir_into_superproject(prefix, path);
1913
1914                 free(real_sub_git_dir);
1915                 free(real_common_git_dir);
1916         }
1917         strbuf_release(&gitdir);
1918
1919         if (flags & ABSORB_GITDIR_RECURSE_SUBMODULES) {
1920                 struct child_process cp = CHILD_PROCESS_INIT;
1921                 struct strbuf sb = STRBUF_INIT;
1922
1923                 if (flags & ~ABSORB_GITDIR_RECURSE_SUBMODULES)
1924                         die("BUG: we don't know how to pass the flags down?");
1925
1926                 strbuf_addstr(&sb, get_super_prefix_or_empty());
1927                 strbuf_addstr(&sb, path);
1928                 strbuf_addch(&sb, '/');
1929
1930                 cp.dir = path;
1931                 cp.git_cmd = 1;
1932                 cp.no_stdin = 1;
1933                 argv_array_pushl(&cp.args, "--super-prefix", sb.buf,
1934                                            "submodule--helper",
1935                                            "absorb-git-dirs", NULL);
1936                 prepare_submodule_repo_env(&cp.env_array);
1937                 if (run_command(&cp))
1938                         die(_("could not recurse into submodule '%s'"), path);
1939
1940                 strbuf_release(&sb);
1941         }
1942 }
1943
1944 const char *get_superproject_working_tree(void)
1945 {
1946         struct child_process cp = CHILD_PROCESS_INIT;
1947         struct strbuf sb = STRBUF_INIT;
1948         const char *one_up = real_path_if_valid("../");
1949         const char *cwd = xgetcwd();
1950         const char *ret = NULL;
1951         const char *subpath;
1952         int code;
1953         ssize_t len;
1954
1955         if (!is_inside_work_tree())
1956                 /*
1957                  * FIXME:
1958                  * We might have a superproject, but it is harder
1959                  * to determine.
1960                  */
1961                 return NULL;
1962
1963         if (!one_up)
1964                 return NULL;
1965
1966         subpath = relative_path(cwd, one_up, &sb);
1967
1968         prepare_submodule_repo_env(&cp.env_array);
1969         argv_array_pop(&cp.env_array);
1970
1971         argv_array_pushl(&cp.args, "--literal-pathspecs", "-C", "..",
1972                         "ls-files", "-z", "--stage", "--full-name", "--",
1973                         subpath, NULL);
1974         strbuf_reset(&sb);
1975
1976         cp.no_stdin = 1;
1977         cp.no_stderr = 1;
1978         cp.out = -1;
1979         cp.git_cmd = 1;
1980
1981         if (start_command(&cp))
1982                 die(_("could not start ls-files in .."));
1983
1984         len = strbuf_read(&sb, cp.out, PATH_MAX);
1985         close(cp.out);
1986
1987         if (starts_with(sb.buf, "160000")) {
1988                 int super_sub_len;
1989                 int cwd_len = strlen(cwd);
1990                 char *super_sub, *super_wt;
1991
1992                 /*
1993                  * There is a superproject having this repo as a submodule.
1994                  * The format is <mode> SP <hash> SP <stage> TAB <full name> \0,
1995                  * We're only interested in the name after the tab.
1996                  */
1997                 super_sub = strchr(sb.buf, '\t') + 1;
1998                 super_sub_len = sb.buf + sb.len - super_sub - 1;
1999
2000                 if (super_sub_len > cwd_len ||
2001                     strcmp(&cwd[cwd_len - super_sub_len], super_sub))
2002                         die (_("BUG: returned path string doesn't match cwd?"));
2003
2004                 super_wt = xstrdup(cwd);
2005                 super_wt[cwd_len - super_sub_len] = '\0';
2006
2007                 ret = real_path(super_wt);
2008                 free(super_wt);
2009         }
2010         strbuf_release(&sb);
2011
2012         code = finish_command(&cp);
2013
2014         if (code == 128)
2015                 /* '../' is not a git repository */
2016                 return NULL;
2017         if (code == 0 && len == 0)
2018                 /* There is an unrelated git repository at '../' */
2019                 return NULL;
2020         if (code)
2021                 die(_("ls-tree returned unexpected return code %d"), code);
2022
2023         return ret;
2024 }
2025
2026 int submodule_to_gitdir(struct strbuf *buf, const char *submodule)
2027 {
2028         const struct submodule *sub;
2029         const char *git_dir;
2030         int ret = 0;
2031
2032         strbuf_reset(buf);
2033         strbuf_addstr(buf, submodule);
2034         strbuf_complete(buf, '/');
2035         strbuf_addstr(buf, ".git");
2036
2037         git_dir = read_gitfile(buf->buf);
2038         if (git_dir) {
2039                 strbuf_reset(buf);
2040                 strbuf_addstr(buf, git_dir);
2041         }
2042         if (!is_git_directory(buf->buf)) {
2043                 gitmodules_config();
2044                 sub = submodule_from_path(null_sha1, submodule);
2045                 if (!sub) {
2046                         ret = -1;
2047                         goto cleanup;
2048                 }
2049                 strbuf_reset(buf);
2050                 strbuf_git_path(buf, "%s/%s", "modules", sub->name);
2051         }
2052
2053 cleanup:
2054         return ret;
2055 }