worktree.c

   1 #define USE_THE_REPOSITORY_VARIABLE
   2
   3 #include "git-compat-util.h"
   4 #include "abspath.h"
   5 #include "environment.h"
   6 #include "gettext.h"
   7 #include "path.h"
   8 #include "repository.h"
   9 #include "refs.h"
  10 #include "setup.h"
  11 #include "strbuf.h"
  12 #include "worktree.h"
  13 #include "dir.h"
  14 #include "wt-status.h"
  15 #include "config.h"
  16
  17 void free_worktree(struct worktree *worktree)
  18 {
  19         if (!worktree)
  20                 return;
  21         free(worktree->path);
  22         free(worktree->id);
  23         free(worktree->head_ref);
  24         free(worktree->lock_reason);
  25         free(worktree->prune_reason);
  26         free(worktree);
  27 }
  28
  29 void free_worktrees(struct worktree **worktrees)
  30 {
  31         int i = 0;
  32         for (i = 0; worktrees[i]; i++)
  33                 free_worktree(worktrees[i]);
  34         free (worktrees);
  35 }
  36
  37 /**
  38  * Update head_oid, head_ref and is_detached of the given worktree
  39  */
  40 static void add_head_info(struct worktree *wt)
  41 {
  42         int flags;
  43         const char *target;
  44
  45         target = refs_resolve_ref_unsafe(get_worktree_ref_store(wt),
  46                                          "HEAD",
  47                                          0,
  48                                          &wt->head_oid, &flags);
  49         if (!target)
  50                 return;
  51
  52         if (flags & REF_ISSYMREF)
  53                 wt->head_ref = xstrdup(target);
  54         else
  55                 wt->is_detached = 1;
  56 }
  57
  58 static int is_current_worktree(struct worktree *wt)
  59 {
  60         char *git_dir = absolute_pathdup(repo_get_git_dir(the_repository));
  61         const char *wt_git_dir = get_worktree_git_dir(wt);
  62         int is_current = !fspathcmp(git_dir, absolute_path(wt_git_dir));
  63         free(git_dir);
  64         return is_current;
  65 }
  66
  67 /**
  68  * get the main worktree
  69  */
  70 static struct worktree *get_main_worktree(int skip_reading_head)
  71 {
  72         struct worktree *worktree = NULL;
  73         struct strbuf worktree_path = STRBUF_INIT;
  74
  75         strbuf_add_real_path(&worktree_path, repo_get_common_dir(the_repository));
  76         strbuf_strip_suffix(&worktree_path, "/.git");
  77
  78         CALLOC_ARRAY(worktree, 1);
  79         worktree->repo = the_repository;
  80         worktree->path = strbuf_detach(&worktree_path, NULL);
  81         /*
  82          * NEEDSWORK: If this function is called from a secondary worktree and
  83          * config.worktree is present, is_bare_repository_cfg will reflect the
  84          * contents of config.worktree, not the contents of the main worktree.
  85          * This means that worktree->is_bare may be set to 0 even if the main
  86          * worktree is configured to be bare.
  87          */
  88         worktree->is_bare = (is_bare_repository_cfg == 1) ||
  89                 is_bare_repository();
  90         worktree->is_current = is_current_worktree(worktree);
  91         if (!skip_reading_head)
  92                 add_head_info(worktree);
  93         return worktree;
  94 }
  95
  96 struct worktree *get_linked_worktree(const char *id,
  97                                      int skip_reading_head)
  98 {
  99         struct worktree *worktree = NULL;
 100         struct strbuf path = STRBUF_INIT;
 101         struct strbuf worktree_path = STRBUF_INIT;
 102
 103         if (!id)
 104                 die("Missing linked worktree name");
 105
 106         strbuf_git_common_path(&path, the_repository, "worktrees/%s/gitdir", id);
 107         if (strbuf_read_file(&worktree_path, path.buf, 0) <= 0)
 108                 /* invalid gitdir file */
 109                 goto done;
 110         strbuf_rtrim(&worktree_path);
 111         strbuf_strip_suffix(&worktree_path, "/.git");
 112
 113         CALLOC_ARRAY(worktree, 1);
 114         worktree->repo = the_repository;
 115         worktree->path = strbuf_detach(&worktree_path, NULL);
 116         worktree->id = xstrdup(id);
 117         worktree->is_current = is_current_worktree(worktree);
 118         if (!skip_reading_head)
 119                 add_head_info(worktree);
 120
 121 done:
 122         strbuf_release(&path);
 123         strbuf_release(&worktree_path);
 124         return worktree;
 125 }
 126
 127 /*
 128  * NEEDSWORK: This function exists so that we can look up metadata of a
 129  * worktree without trying to access any of its internals like the refdb. It
 130  * would be preferable to instead have a corruption-tolerant function for
 131  * retrieving worktree metadata that could be used when the worktree is known
 132  * to not be in a healthy state, e.g. when creating or repairing it.
 133  */
 134 static struct worktree **get_worktrees_internal(int skip_reading_head)
 135 {
 136         struct worktree **list = NULL;
 137         struct strbuf path = STRBUF_INIT;
 138         DIR *dir;
 139         struct dirent *d;
 140         int counter = 0, alloc = 2;
 141
 142         ALLOC_ARRAY(list, alloc);
 143
 144         list[counter++] = get_main_worktree(skip_reading_head);
 145
 146         strbuf_addf(&path, "%s/worktrees", repo_get_common_dir(the_repository));
 147         dir = opendir(path.buf);
 148         strbuf_release(&path);
 149         if (dir) {
 150                 while ((d = readdir_skip_dot_and_dotdot(dir)) != NULL) {
 151                         struct worktree *linked = NULL;
 152
 153                         if ((linked = get_linked_worktree(d->d_name, skip_reading_head))) {
 154                                 ALLOC_GROW(list, counter + 1, alloc);
 155                                 list[counter++] = linked;
 156                         }
 157                 }
 158                 closedir(dir);
 159         }
 160         ALLOC_GROW(list, counter + 1, alloc);
 161         list[counter] = NULL;
 162
 163         return list;
 164 }
 165
 166 struct worktree **get_worktrees(void)
 167 {
 168         return get_worktrees_internal(0);
 169 }
 170
 171 const char *get_worktree_git_dir(const struct worktree *wt)
 172 {
 173         if (!wt)
 174                 return repo_get_git_dir(the_repository);
 175         else if (!wt->id)
 176                 return repo_get_common_dir(the_repository);
 177         else
 178                 return git_common_path("worktrees/%s", wt->id);
 179 }
 180
 181 static struct worktree *find_worktree_by_suffix(struct worktree **list,
 182                                                 const char *suffix)
 183 {
 184         struct worktree *found = NULL;
 185         int nr_found = 0, suffixlen;
 186
 187         suffixlen = strlen(suffix);
 188         if (!suffixlen)
 189                 return NULL;
 190
 191         for (; *list && nr_found < 2; list++) {
 192                 const char      *path    = (*list)->path;
 193                 int              pathlen = strlen(path);
 194                 int              start   = pathlen - suffixlen;
 195
 196                 /* suffix must start at directory boundary */
 197                 if ((!start || (start > 0 && is_dir_sep(path[start - 1]))) &&
 198                     !fspathcmp(suffix, path + start)) {
 199                         found = *list;
 200                         nr_found++;
 201                 }
 202         }
 203         return nr_found == 1 ? found : NULL;
 204 }
 205
 206 struct worktree *find_worktree(struct worktree **list,
 207                                const char *prefix,
 208                                const char *arg)
 209 {
 210         struct worktree *wt;
 211         char *to_free = NULL;
 212
 213         if ((wt = find_worktree_by_suffix(list, arg)))
 214                 return wt;
 215
 216         if (prefix)
 217                 arg = to_free = prefix_filename(prefix, arg);
 218         wt = find_worktree_by_path(list, arg);
 219         free(to_free);
 220         return wt;
 221 }
 222
 223 struct worktree *find_worktree_by_path(struct worktree **list, const char *p)
 224 {
 225         struct strbuf wt_path = STRBUF_INIT;
 226         char *path = real_pathdup(p, 0);
 227
 228         if (!path)
 229                 return NULL;
 230         for (; *list; list++) {
 231                 if (!strbuf_realpath(&wt_path, (*list)->path, 0))
 232                         continue;
 233
 234                 if (!fspathcmp(path, wt_path.buf))
 235                         break;
 236         }
 237         free(path);
 238         strbuf_release(&wt_path);
 239         return *list;
 240 }
 241
 242 int is_main_worktree(const struct worktree *wt)
 243 {
 244         return !wt->id;
 245 }
 246
 247 const char *worktree_lock_reason(struct worktree *wt)
 248 {
 249         if (is_main_worktree(wt))
 250                 return NULL;
 251
 252         if (!wt->lock_reason_valid) {
 253                 struct strbuf path = STRBUF_INIT;
 254
 255                 strbuf_addstr(&path, worktree_git_path(the_repository, wt, "locked"));
 256                 if (file_exists(path.buf)) {
 257                         struct strbuf lock_reason = STRBUF_INIT;
 258                         if (strbuf_read_file(&lock_reason, path.buf, 0) < 0)
 259                                 die_errno(_("failed to read '%s'"), path.buf);
 260                         strbuf_trim(&lock_reason);
 261                         wt->lock_reason = strbuf_detach(&lock_reason, NULL);
 262                 } else
 263                         wt->lock_reason = NULL;
 264                 wt->lock_reason_valid = 1;
 265                 strbuf_release(&path);
 266         }
 267
 268         return wt->lock_reason;
 269 }
 270
 271 const char *worktree_prune_reason(struct worktree *wt, timestamp_t expire)
 272 {
 273         struct strbuf reason = STRBUF_INIT;
 274         char *path = NULL;
 275
 276         if (is_main_worktree(wt))
 277                 return NULL;
 278         if (wt->prune_reason_valid)
 279                 return wt->prune_reason;
 280
 281         if (should_prune_worktree(wt->id, &reason, &path, expire))
 282                 wt->prune_reason = strbuf_detach(&reason, NULL);
 283         wt->prune_reason_valid = 1;
 284
 285         strbuf_release(&reason);
 286         free(path);
 287         return wt->prune_reason;
 288 }
 289
 290 /* convenient wrapper to deal with NULL strbuf */
 291 __attribute__((format (printf, 2, 3)))
 292 static void strbuf_addf_gently(struct strbuf *buf, const char *fmt, ...)
 293 {
 294         va_list params;
 295
 296         if (!buf)
 297                 return;
 298
 299         va_start(params, fmt);
 300         strbuf_vaddf(buf, fmt, params);
 301         va_end(params);
 302 }
 303
 304 int validate_worktree(const struct worktree *wt, struct strbuf *errmsg,
 305                       unsigned flags)
 306 {
 307         struct strbuf wt_path = STRBUF_INIT;
 308         struct strbuf realpath = STRBUF_INIT;
 309         char *path = NULL;
 310         int err, ret = -1;
 311
 312         strbuf_addf(&wt_path, "%s/.git", wt->path);
 313
 314         if (is_main_worktree(wt)) {
 315                 if (is_directory(wt_path.buf)) {
 316                         ret = 0;
 317                         goto done;
 318                 }
 319                 /*
 320                  * Main worktree using .git file to point to the
 321                  * repository would make it impossible to know where
 322                  * the actual worktree is if this function is executed
 323                  * from another worktree. No .git file support for now.
 324                  */
 325                 strbuf_addf_gently(errmsg,
 326                                    _("'%s' at main working tree is not the repository directory"),
 327                                    wt_path.buf);
 328                 goto done;
 329         }
 330
 331         /*
 332          * Make sure "gitdir" file points to a real .git file and that
 333          * file points back here.
 334          */
 335         if (!is_absolute_path(wt->path)) {
 336                 strbuf_addf_gently(errmsg,
 337                                    _("'%s' file does not contain absolute path to the working tree location"),
 338                                    git_common_path("worktrees/%s/gitdir", wt->id));
 339                 goto done;
 340         }
 341
 342         if (flags & WT_VALIDATE_WORKTREE_MISSING_OK &&
 343             !file_exists(wt->path)) {
 344                 ret = 0;
 345                 goto done;
 346         }
 347
 348         if (!file_exists(wt_path.buf)) {
 349                 strbuf_addf_gently(errmsg, _("'%s' does not exist"), wt_path.buf);
 350                 goto done;
 351         }
 352
 353         path = xstrdup_or_null(read_gitfile_gently(wt_path.buf, &err));
 354         if (!path) {
 355                 strbuf_addf_gently(errmsg, _("'%s' is not a .git file, error code %d"),
 356                                    wt_path.buf, err);
 357                 goto done;
 358         }
 359
 360         strbuf_realpath(&realpath, git_common_path("worktrees/%s", wt->id), 1);
 361         ret = fspathcmp(path, realpath.buf);
 362
 363         if (ret)
 364                 strbuf_addf_gently(errmsg, _("'%s' does not point back to '%s'"),
 365                                    wt->path, git_common_path("worktrees/%s", wt->id));
 366 done:
 367         free(path);
 368         strbuf_release(&wt_path);
 369         strbuf_release(&realpath);
 370         return ret;
 371 }
 372
 373 void update_worktree_location(struct worktree *wt, const char *path_)
 374 {
 375         struct strbuf path = STRBUF_INIT;
 376
 377         if (is_main_worktree(wt))
 378                 BUG("can't relocate main worktree");
 379
 380         strbuf_realpath(&path, path_, 1);
 381         if (fspathcmp(wt->path, path.buf)) {
 382                 write_file(git_common_path("worktrees/%s/gitdir", wt->id),
 383                            "%s/.git", path.buf);
 384                 free(wt->path);
 385                 wt->path = strbuf_detach(&path, NULL);
 386         }
 387         strbuf_release(&path);
 388 }
 389
 390 int is_worktree_being_rebased(const struct worktree *wt,
 391                               const char *target)
 392 {
 393         struct wt_status_state state;
 394         int found_rebase;
 395
 396         memset(&state, 0, sizeof(state));
 397         found_rebase = wt_status_check_rebase(wt, &state) &&
 398                        (state.rebase_in_progress ||
 399                         state.rebase_interactive_in_progress) &&
 400                        state.branch &&
 401                        skip_prefix(target, "refs/heads/", &target) &&
 402                        !strcmp(state.branch, target);
 403         wt_status_state_free_buffers(&state);
 404         return found_rebase;
 405 }
 406
 407 int is_worktree_being_bisected(const struct worktree *wt,
 408                                const char *target)
 409 {
 410         struct wt_status_state state;
 411         int found_bisect;
 412
 413         memset(&state, 0, sizeof(state));
 414         found_bisect = wt_status_check_bisect(wt, &state) &&
 415                        state.bisecting_from &&
 416                        skip_prefix(target, "refs/heads/", &target) &&
 417                        !strcmp(state.bisecting_from, target);
 418         wt_status_state_free_buffers(&state);
 419         return found_bisect;
 420 }
 421
 422 /*
 423  * note: this function should be able to detect shared symref even if
 424  * HEAD is temporarily detached (e.g. in the middle of rebase or
 425  * bisect). New commands that do similar things should update this
 426  * function as well.
 427  */
 428 int is_shared_symref(const struct worktree *wt, const char *symref,
 429                      const char *target)
 430 {
 431         const char *symref_target;
 432         struct ref_store *refs;
 433         int flags;
 434
 435         if (wt->is_bare)
 436                 return 0;
 437
 438         if (wt->is_detached && !strcmp(symref, "HEAD")) {
 439                 if (is_worktree_being_rebased(wt, target))
 440                         return 1;
 441                 if (is_worktree_being_bisected(wt, target))
 442                         return 1;
 443         }
 444
 445         refs = get_worktree_ref_store(wt);
 446         symref_target = refs_resolve_ref_unsafe(refs, symref, 0,
 447                                                 NULL, &flags);
 448         if ((flags & REF_ISSYMREF) &&
 449             symref_target && !strcmp(symref_target, target))
 450                 return 1;
 451
 452         return 0;
 453 }
 454
 455 const struct worktree *find_shared_symref(struct worktree **worktrees,
 456                                           const char *symref,
 457                                           const char *target)
 458 {
 459
 460         for (int i = 0; worktrees[i]; i++)
 461                 if (is_shared_symref(worktrees[i], symref, target))
 462                         return worktrees[i];
 463
 464         return NULL;
 465 }
 466
 467 int submodule_uses_worktrees(const char *path)
 468 {
 469         char *submodule_gitdir;
 470         struct strbuf sb = STRBUF_INIT, err = STRBUF_INIT;
 471         DIR *dir;
 472         struct dirent *d;
 473         int ret = 0;
 474         struct repository_format format = REPOSITORY_FORMAT_INIT;
 475
 476         submodule_gitdir = git_pathdup_submodule(path, "%s", "");
 477         if (!submodule_gitdir)
 478                 return 0;
 479
 480         /* The env would be set for the superproject. */
 481         get_common_dir_noenv(&sb, submodule_gitdir);
 482         free(submodule_gitdir);
 483
 484         strbuf_addstr(&sb, "/config");
 485         read_repository_format(&format, sb.buf);
 486         if (verify_repository_format(&format, &err)) {
 487                 strbuf_release(&err);
 488                 strbuf_release(&sb);
 489                 clear_repository_format(&format);
 490                 return 1;
 491         }
 492         clear_repository_format(&format);
 493         strbuf_release(&err);
 494
 495         /* Replace config by worktrees. */
 496         strbuf_setlen(&sb, sb.len - strlen("config"));
 497         strbuf_addstr(&sb, "worktrees");
 498
 499         /* See if there is any file inside the worktrees directory. */
 500         dir = opendir(sb.buf);
 501         strbuf_release(&sb);
 502
 503         if (!dir)
 504                 return 0;
 505
 506         d = readdir_skip_dot_and_dotdot(dir);
 507         if (d)
 508                 ret = 1;
 509         closedir(dir);
 510         return ret;
 511 }
 512
 513 void strbuf_worktree_ref(const struct worktree *wt,
 514                          struct strbuf *sb,
 515                          const char *refname)
 516 {
 517         if (parse_worktree_ref(refname, NULL, NULL, NULL) ==
 518                     REF_WORKTREE_CURRENT &&
 519             wt && !wt->is_current) {
 520                 if (is_main_worktree(wt))
 521                         strbuf_addstr(sb, "main-worktree/");
 522                 else
 523                         strbuf_addf(sb, "worktrees/%s/", wt->id);
 524         }
 525         strbuf_addstr(sb, refname);
 526 }
 527
 528 int other_head_refs(each_ref_fn fn, void *cb_data)
 529 {
 530         struct worktree **worktrees, **p;
 531         struct strbuf refname = STRBUF_INIT;
 532         int ret = 0;
 533
 534         worktrees = get_worktrees();
 535         for (p = worktrees; *p; p++) {
 536                 struct worktree *wt = *p;
 537                 struct object_id oid;
 538                 int flag;
 539
 540                 if (wt->is_current)
 541                         continue;
 542
 543                 strbuf_reset(&refname);
 544                 strbuf_worktree_ref(wt, &refname, "HEAD");
 545                 if (refs_resolve_ref_unsafe(get_main_ref_store(the_repository),
 546                                             refname.buf,
 547                                             RESOLVE_REF_READING,
 548                                             &oid, &flag))
 549                         ret = fn(refname.buf, NULL, &oid, flag, cb_data);
 550                 if (ret)
 551                         break;
 552         }
 553         free_worktrees(worktrees);
 554         strbuf_release(&refname);
 555         return ret;
 556 }
 557
 558 /*
 559  * Repair worktree's /path/to/worktree/.git file if missing, corrupt, or not
 560  * pointing at <repo>/worktrees/<id>.
 561  */
 562 static void repair_gitfile(struct worktree *wt,
 563                            worktree_repair_fn fn, void *cb_data)
 564 {
 565         struct strbuf dotgit = STRBUF_INIT;
 566         struct strbuf repo = STRBUF_INIT;
 567         char *backlink;
 568         const char *repair = NULL;
 569         int err;
 570
 571         /* missing worktree can't be repaired */
 572         if (!file_exists(wt->path))
 573                 return;
 574
 575         if (!is_directory(wt->path)) {
 576                 fn(1, wt->path, _("not a directory"), cb_data);
 577                 return;
 578         }
 579
 580         strbuf_realpath(&repo, git_common_path("worktrees/%s", wt->id), 1);
 581         strbuf_addf(&dotgit, "%s/.git", wt->path);
 582         backlink = xstrdup_or_null(read_gitfile_gently(dotgit.buf, &err));
 583
 584         if (err == READ_GITFILE_ERR_NOT_A_FILE)
 585                 fn(1, wt->path, _(".git is not a file"), cb_data);
 586         else if (err)
 587                 repair = _(".git file broken");
 588         else if (fspathcmp(backlink, repo.buf))
 589                 repair = _(".git file incorrect");
 590
 591         if (repair) {
 592                 fn(0, wt->path, repair, cb_data);
 593                 write_file(dotgit.buf, "gitdir: %s", repo.buf);
 594         }
 595
 596         free(backlink);
 597         strbuf_release(&repo);
 598         strbuf_release(&dotgit);
 599 }
 600
 601 static void repair_noop(int iserr UNUSED,
 602                         const char *path UNUSED,
 603                         const char *msg UNUSED,
 604                         void *cb_data UNUSED)
 605 {
 606         /* nothing */
 607 }
 608
 609 void repair_worktrees(worktree_repair_fn fn, void *cb_data)
 610 {
 611         struct worktree **worktrees = get_worktrees_internal(1);
 612         struct worktree **wt = worktrees + 1; /* +1 skips main worktree */
 613
 614         if (!fn)
 615                 fn = repair_noop;
 616         for (; *wt; wt++)
 617                 repair_gitfile(*wt, fn, cb_data);
 618         free_worktrees(worktrees);
 619 }
 620
 621 static int is_main_worktree_path(const char *path)
 622 {
 623         struct strbuf target = STRBUF_INIT;
 624         struct strbuf maindir = STRBUF_INIT;
 625         int cmp;
 626
 627         strbuf_add_real_path(&target, path);
 628         strbuf_strip_suffix(&target, "/.git");
 629         strbuf_add_real_path(&maindir, repo_get_common_dir(the_repository));
 630         strbuf_strip_suffix(&maindir, "/.git");
 631         cmp = fspathcmp(maindir.buf, target.buf);
 632
 633         strbuf_release(&maindir);
 634         strbuf_release(&target);
 635         return !cmp;
 636 }
 637
 638 /*
 639  * If both the main worktree and linked worktree have been moved, then the
 640  * gitfile /path/to/worktree/.git won't point into the repository, thus we
 641  * won't know which <repo>/worktrees/<id>/gitdir to repair. However, we may
 642  * be able to infer the gitdir by manually reading /path/to/worktree/.git,
 643  * extracting the <id>, and checking if <repo>/worktrees/<id> exists.
 644  */
 645 static char *infer_backlink(const char *gitfile)
 646 {
 647         struct strbuf actual = STRBUF_INIT;
 648         struct strbuf inferred = STRBUF_INIT;
 649         const char *id;
 650
 651         if (strbuf_read_file(&actual, gitfile, 0) < 0)
 652                 goto error;
 653         if (!starts_with(actual.buf, "gitdir:"))
 654                 goto error;
 655         if (!(id = find_last_dir_sep(actual.buf)))
 656                 goto error;
 657         strbuf_trim(&actual);
 658         id++; /* advance past '/' to point at <id> */
 659         if (!*id)
 660                 goto error;
 661         strbuf_git_common_path(&inferred, the_repository, "worktrees/%s", id);
 662         if (!is_directory(inferred.buf))
 663                 goto error;
 664
 665         strbuf_release(&actual);
 666         return strbuf_detach(&inferred, NULL);
 667
 668 error:
 669         strbuf_release(&actual);
 670         strbuf_release(&inferred);
 671         return NULL;
 672 }
 673
 674 /*
 675  * Repair <repo>/worktrees/<id>/gitdir if missing, corrupt, or not pointing at
 676  * the worktree's path.
 677  */
 678 void repair_worktree_at_path(const char *path,
 679                              worktree_repair_fn fn, void *cb_data)
 680 {
 681         struct strbuf dotgit = STRBUF_INIT;
 682         struct strbuf realdotgit = STRBUF_INIT;
 683         struct strbuf gitdir = STRBUF_INIT;
 684         struct strbuf olddotgit = STRBUF_INIT;
 685         char *backlink = NULL;
 686         const char *repair = NULL;
 687         int err;
 688
 689         if (!fn)
 690                 fn = repair_noop;
 691
 692         if (is_main_worktree_path(path))
 693                 goto done;
 694
 695         strbuf_addf(&dotgit, "%s/.git", path);
 696         if (!strbuf_realpath(&realdotgit, dotgit.buf, 0)) {
 697                 fn(1, path, _("not a valid path"), cb_data);
 698                 goto done;
 699         }
 700
 701         backlink = xstrdup_or_null(read_gitfile_gently(realdotgit.buf, &err));
 702         if (err == READ_GITFILE_ERR_NOT_A_FILE) {
 703                 fn(1, realdotgit.buf, _("unable to locate repository; .git is not a file"), cb_data);
 704                 goto done;
 705         } else if (err == READ_GITFILE_ERR_NOT_A_REPO) {
 706                 if (!(backlink = infer_backlink(realdotgit.buf))) {
 707                         fn(1, realdotgit.buf, _("unable to locate repository; .git file does not reference a repository"), cb_data);
 708                         goto done;
 709                 }
 710         } else if (err) {
 711                 fn(1, realdotgit.buf, _("unable to locate repository; .git file broken"), cb_data);
 712                 goto done;
 713         }
 714
 715         strbuf_addf(&gitdir, "%s/gitdir", backlink);
 716         if (strbuf_read_file(&olddotgit, gitdir.buf, 0) < 0)
 717                 repair = _("gitdir unreadable");
 718         else {
 719                 strbuf_rtrim(&olddotgit);
 720                 if (fspathcmp(olddotgit.buf, realdotgit.buf))
 721                         repair = _("gitdir incorrect");
 722         }
 723
 724         if (repair) {
 725                 fn(0, gitdir.buf, repair, cb_data);
 726                 write_file(gitdir.buf, "%s", realdotgit.buf);
 727         }
 728 done:
 729         free(backlink);
 730         strbuf_release(&olddotgit);
 731         strbuf_release(&gitdir);
 732         strbuf_release(&realdotgit);
 733         strbuf_release(&dotgit);
 734 }
 735
 736 int should_prune_worktree(const char *id, struct strbuf *reason, char **wtpath, timestamp_t expire)
 737 {
 738         struct stat st;
 739         char *path;
 740         int fd;
 741         size_t len;
 742         ssize_t read_result;
 743
 744         *wtpath = NULL;
 745         if (!is_directory(git_path("worktrees/%s", id))) {
 746                 strbuf_addstr(reason, _("not a valid directory"));
 747                 return 1;
 748         }
 749         if (file_exists(git_path("worktrees/%s/locked", id)))
 750                 return 0;
 751         if (stat(git_path("worktrees/%s/gitdir", id), &st)) {
 752                 strbuf_addstr(reason, _("gitdir file does not exist"));
 753                 return 1;
 754         }
 755         fd = open(git_path("worktrees/%s/gitdir", id), O_RDONLY);
 756         if (fd < 0) {
 757                 strbuf_addf(reason, _("unable to read gitdir file (%s)"),
 758                             strerror(errno));
 759                 return 1;
 760         }
 761         len = xsize_t(st.st_size);
 762         path = xmallocz(len);
 763
 764         read_result = read_in_full(fd, path, len);
 765         if (read_result < 0) {
 766                 strbuf_addf(reason, _("unable to read gitdir file (%s)"),
 767                             strerror(errno));
 768                 close(fd);
 769                 free(path);
 770                 return 1;
 771         }
 772         close(fd);
 773
 774         if (read_result != len) {
 775                 strbuf_addf(reason,
 776                             _("short read (expected %"PRIuMAX" bytes, read %"PRIuMAX")"),
 777                             (uintmax_t)len, (uintmax_t)read_result);
 778                 free(path);
 779                 return 1;
 780         }
 781         while (len && (path[len - 1] == '\n' || path[len - 1] == '\r'))
 782                 len--;
 783         if (!len) {
 784                 strbuf_addstr(reason, _("invalid gitdir file"));
 785                 free(path);
 786                 return 1;
 787         }
 788         path[len] = '\0';
 789         if (!file_exists(path)) {
 790                 if (stat(git_path("worktrees/%s/index", id), &st) ||
 791                     st.st_mtime <= expire) {
 792                         strbuf_addstr(reason, _("gitdir file points to non-existent location"));
 793                         free(path);
 794                         return 1;
 795                 } else {
 796                         *wtpath = path;
 797                         return 0;
 798                 }
 799         }
 800         *wtpath = path;
 801         return 0;
 802 }
 803
 804 static int move_config_setting(const char *key, const char *value,
 805                                const char *from_file, const char *to_file)
 806 {
 807         if (git_config_set_in_file_gently(to_file, key, NULL, value))
 808                 return error(_("unable to set %s in '%s'"), key, to_file);
 809         if (git_config_set_in_file_gently(from_file, key, NULL, NULL))
 810                 return error(_("unable to unset %s in '%s'"), key, from_file);
 811         return 0;
 812 }
 813
 814 int init_worktree_config(struct repository *r)
 815 {
 816         int res = 0;
 817         int bare = 0;
 818         struct config_set cs = { { 0 } };
 819         const char *core_worktree;
 820         char *common_config_file;
 821         char *main_worktree_file;
 822
 823         /*
 824          * If the extension is already enabled, then we can skip the
 825          * upgrade process.
 826          */
 827         if (r->repository_format_worktree_config)
 828                 return 0;
 829         if ((res = git_config_set_gently("extensions.worktreeConfig", "true")))
 830                 return error(_("failed to set extensions.worktreeConfig setting"));
 831
 832         common_config_file = xstrfmt("%s/config", r->commondir);
 833         main_worktree_file = xstrfmt("%s/config.worktree", r->commondir);
 834
 835         git_configset_init(&cs);
 836         git_configset_add_file(&cs, common_config_file);
 837
 838         /*
 839          * If core.bare is true in the common config file, then we need to
 840          * move it to the main worktree's config file or it will break all
 841          * worktrees. If it is false, then leave it in place because it
 842          * _could_ be negating a global core.bare=true.
 843          */
 844         if (!git_configset_get_bool(&cs, "core.bare", &bare) && bare) {
 845                 if ((res = move_config_setting("core.bare", "true",
 846                                                common_config_file,
 847                                                main_worktree_file)))
 848                         goto cleanup;
 849         }
 850         /*
 851          * If core.worktree is set, then the main worktree is located
 852          * somewhere different than the parent of the common Git dir.
 853          * Relocate that value to avoid breaking all worktrees with this
 854          * upgrade to worktree config.
 855          */
 856         if (!git_configset_get_value(&cs, "core.worktree", &core_worktree, NULL)) {
 857                 if ((res = move_config_setting("core.worktree", core_worktree,
 858                                                common_config_file,
 859                                                main_worktree_file)))
 860                         goto cleanup;
 861         }
 862
 863         /*
 864          * Ensure that we use worktree config for the remaining lifetime
 865          * of the current process.
 866          */
 867         r->repository_format_worktree_config = 1;
 868
 869 cleanup:
 870         git_configset_clear(&cs);
 871         free(common_config_file);
 872         free(main_worktree_file);
 873         return res;
 874 }