worktree.c

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