Merge branch 'rb/hashmap-h-compilation-fix' into maint
[git] / builtin / fsck.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "config.h"
4 #include "commit.h"
5 #include "tree.h"
6 #include "blob.h"
7 #include "tag.h"
8 #include "refs.h"
9 #include "pack.h"
10 #include "cache-tree.h"
11 #include "tree-walk.h"
12 #include "fsck.h"
13 #include "parse-options.h"
14 #include "dir.h"
15 #include "progress.h"
16 #include "streaming.h"
17 #include "decorate.h"
18 #include "packfile.h"
19
20 #define REACHABLE 0x0001
21 #define SEEN      0x0002
22 #define HAS_OBJ   0x0004
23 /* This flag is set if something points to this object. */
24 #define USED      0x0008
25
26 static int show_root;
27 static int show_tags;
28 static int show_unreachable;
29 static int include_reflogs = 1;
30 static int check_full = 1;
31 static int connectivity_only;
32 static int check_strict;
33 static int keep_cache_objects;
34 static struct fsck_options fsck_walk_options = FSCK_OPTIONS_DEFAULT;
35 static struct fsck_options fsck_obj_options = FSCK_OPTIONS_DEFAULT;
36 static struct object_id head_oid;
37 static const char *head_points_at;
38 static int errors_found;
39 static int write_lost_and_found;
40 static int verbose;
41 static int show_progress = -1;
42 static int show_dangling = 1;
43 static int name_objects;
44 #define ERROR_OBJECT 01
45 #define ERROR_REACHABLE 02
46 #define ERROR_PACK 04
47 #define ERROR_REFS 010
48
49 static const char *describe_object(struct object *obj)
50 {
51         static struct strbuf buf = STRBUF_INIT;
52         char *name = name_objects ?
53                 lookup_decoration(fsck_walk_options.object_names, obj) : NULL;
54
55         strbuf_reset(&buf);
56         strbuf_addstr(&buf, oid_to_hex(&obj->oid));
57         if (name)
58                 strbuf_addf(&buf, " (%s)", name);
59
60         return buf.buf;
61 }
62
63 static const char *printable_type(struct object *obj)
64 {
65         const char *ret;
66
67         if (obj->type == OBJ_NONE) {
68                 enum object_type type = sha1_object_info(obj->oid.hash, NULL);
69                 if (type > 0)
70                         object_as_type(obj, type, 0);
71         }
72
73         ret = typename(obj->type);
74         if (!ret)
75                 ret = "unknown";
76
77         return ret;
78 }
79
80 static int fsck_config(const char *var, const char *value, void *cb)
81 {
82         if (strcmp(var, "fsck.skiplist") == 0) {
83                 const char *path;
84                 struct strbuf sb = STRBUF_INIT;
85
86                 if (git_config_pathname(&path, var, value))
87                         return 1;
88                 strbuf_addf(&sb, "skiplist=%s", path);
89                 free((char *)path);
90                 fsck_set_msg_types(&fsck_obj_options, sb.buf);
91                 strbuf_release(&sb);
92                 return 0;
93         }
94
95         if (skip_prefix(var, "fsck.", &var)) {
96                 fsck_set_msg_type(&fsck_obj_options, var, value);
97                 return 0;
98         }
99
100         return git_default_config(var, value, cb);
101 }
102
103 static void objreport(struct object *obj, const char *msg_type,
104                         const char *err)
105 {
106         fprintf(stderr, "%s in %s %s: %s\n",
107                 msg_type, printable_type(obj), describe_object(obj), err);
108 }
109
110 static int objerror(struct object *obj, const char *err)
111 {
112         errors_found |= ERROR_OBJECT;
113         objreport(obj, "error", err);
114         return -1;
115 }
116
117 static int fsck_error_func(struct fsck_options *o,
118         struct object *obj, int type, const char *message)
119 {
120         objreport(obj, (type == FSCK_WARN) ? "warning" : "error", message);
121         return (type == FSCK_WARN) ? 0 : 1;
122 }
123
124 static struct object_array pending;
125
126 static int mark_object(struct object *obj, int type, void *data, struct fsck_options *options)
127 {
128         struct object *parent = data;
129
130         /*
131          * The only case data is NULL or type is OBJ_ANY is when
132          * mark_object_reachable() calls us.  All the callers of
133          * that function has non-NULL obj hence ...
134          */
135         if (!obj) {
136                 /* ... these references to parent->fld are safe here */
137                 printf("broken link from %7s %s\n",
138                            printable_type(parent), describe_object(parent));
139                 printf("broken link from %7s %s\n",
140                            (type == OBJ_ANY ? "unknown" : typename(type)), "unknown");
141                 errors_found |= ERROR_REACHABLE;
142                 return 1;
143         }
144
145         if (type != OBJ_ANY && obj->type != type)
146                 /* ... and the reference to parent is safe here */
147                 objerror(parent, "wrong object type in link");
148
149         if (obj->flags & REACHABLE)
150                 return 0;
151         obj->flags |= REACHABLE;
152         if (!(obj->flags & HAS_OBJ)) {
153                 if (parent && !has_object_file(&obj->oid)) {
154                         printf("broken link from %7s %s\n",
155                                  printable_type(parent), describe_object(parent));
156                         printf("              to %7s %s\n",
157                                  printable_type(obj), describe_object(obj));
158                         errors_found |= ERROR_REACHABLE;
159                 }
160                 return 1;
161         }
162
163         add_object_array(obj, NULL, &pending);
164         return 0;
165 }
166
167 static void mark_object_reachable(struct object *obj)
168 {
169         mark_object(obj, OBJ_ANY, NULL, NULL);
170 }
171
172 static int traverse_one_object(struct object *obj)
173 {
174         int result = fsck_walk(obj, obj, &fsck_walk_options);
175
176         if (obj->type == OBJ_TREE) {
177                 struct tree *tree = (struct tree *)obj;
178                 free_tree_buffer(tree);
179         }
180         return result;
181 }
182
183 static int traverse_reachable(void)
184 {
185         struct progress *progress = NULL;
186         unsigned int nr = 0;
187         int result = 0;
188         if (show_progress)
189                 progress = start_delayed_progress(_("Checking connectivity"), 0);
190         while (pending.nr) {
191                 result |= traverse_one_object(object_array_pop(&pending));
192                 display_progress(progress, ++nr);
193         }
194         stop_progress(&progress);
195         return !!result;
196 }
197
198 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
199 {
200         if (!obj)
201                 return 1;
202         obj->flags |= USED;
203         return 0;
204 }
205
206 /*
207  * Check a single reachable object
208  */
209 static void check_reachable_object(struct object *obj)
210 {
211         /*
212          * We obviously want the object to be parsed,
213          * except if it was in a pack-file and we didn't
214          * do a full fsck
215          */
216         if (!(obj->flags & HAS_OBJ)) {
217                 if (has_sha1_pack(obj->oid.hash))
218                         return; /* it is in pack - forget about it */
219                 printf("missing %s %s\n", printable_type(obj),
220                         describe_object(obj));
221                 errors_found |= ERROR_REACHABLE;
222                 return;
223         }
224 }
225
226 /*
227  * Check a single unreachable object
228  */
229 static void check_unreachable_object(struct object *obj)
230 {
231         /*
232          * Missing unreachable object? Ignore it. It's not like
233          * we miss it (since it can't be reached), nor do we want
234          * to complain about it being unreachable (since it does
235          * not exist).
236          */
237         if (!(obj->flags & HAS_OBJ))
238                 return;
239
240         /*
241          * Unreachable object that exists? Show it if asked to,
242          * since this is something that is prunable.
243          */
244         if (show_unreachable) {
245                 printf("unreachable %s %s\n", printable_type(obj),
246                         describe_object(obj));
247                 return;
248         }
249
250         /*
251          * "!USED" means that nothing at all points to it, including
252          * other unreachable objects. In other words, it's the "tip"
253          * of some set of unreachable objects, usually a commit that
254          * got dropped.
255          *
256          * Such starting points are more interesting than some random
257          * set of unreachable objects, so we show them even if the user
258          * hasn't asked for _all_ unreachable objects. If you have
259          * deleted a branch by mistake, this is a prime candidate to
260          * start looking at, for example.
261          */
262         if (!(obj->flags & USED)) {
263                 if (show_dangling)
264                         printf("dangling %s %s\n", printable_type(obj),
265                                describe_object(obj));
266                 if (write_lost_and_found) {
267                         char *filename = git_pathdup("lost-found/%s/%s",
268                                 obj->type == OBJ_COMMIT ? "commit" : "other",
269                                 describe_object(obj));
270                         FILE *f;
271
272                         if (safe_create_leading_directories_const(filename)) {
273                                 error("Could not create lost-found");
274                                 free(filename);
275                                 return;
276                         }
277                         f = xfopen(filename, "w");
278                         if (obj->type == OBJ_BLOB) {
279                                 if (stream_blob_to_fd(fileno(f), &obj->oid, NULL, 1))
280                                         die_errno("Could not write '%s'", filename);
281                         } else
282                                 fprintf(f, "%s\n", describe_object(obj));
283                         if (fclose(f))
284                                 die_errno("Could not finish '%s'",
285                                           filename);
286                         free(filename);
287                 }
288                 return;
289         }
290
291         /*
292          * Otherwise? It's there, it's unreachable, and some other unreachable
293          * object points to it. Ignore it - it's not interesting, and we showed
294          * all the interesting cases above.
295          */
296 }
297
298 static void check_object(struct object *obj)
299 {
300         if (verbose)
301                 fprintf(stderr, "Checking %s\n", describe_object(obj));
302
303         if (obj->flags & REACHABLE)
304                 check_reachable_object(obj);
305         else
306                 check_unreachable_object(obj);
307 }
308
309 static void check_connectivity(void)
310 {
311         int i, max;
312
313         /* Traverse the pending reachable objects */
314         traverse_reachable();
315
316         /* Look up all the requirements, warn about missing objects.. */
317         max = get_max_object_index();
318         if (verbose)
319                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
320
321         for (i = 0; i < max; i++) {
322                 struct object *obj = get_indexed_object(i);
323
324                 if (obj)
325                         check_object(obj);
326         }
327 }
328
329 static int fsck_obj(struct object *obj)
330 {
331         int err;
332
333         if (obj->flags & SEEN)
334                 return 0;
335         obj->flags |= SEEN;
336
337         if (verbose)
338                 fprintf(stderr, "Checking %s %s\n",
339                         printable_type(obj), describe_object(obj));
340
341         if (fsck_walk(obj, NULL, &fsck_obj_options))
342                 objerror(obj, "broken links");
343         err = fsck_object(obj, NULL, 0, &fsck_obj_options);
344         if (err)
345                 goto out;
346
347         if (obj->type == OBJ_COMMIT) {
348                 struct commit *commit = (struct commit *) obj;
349
350                 if (!commit->parents && show_root)
351                         printf("root %s\n", describe_object(&commit->object));
352         }
353
354         if (obj->type == OBJ_TAG) {
355                 struct tag *tag = (struct tag *) obj;
356
357                 if (show_tags && tag->tagged) {
358                         printf("tagged %s %s", printable_type(tag->tagged),
359                                 describe_object(tag->tagged));
360                         printf(" (%s) in %s\n", tag->tag,
361                                 describe_object(&tag->object));
362                 }
363         }
364
365 out:
366         if (obj->type == OBJ_TREE)
367                 free_tree_buffer((struct tree *)obj);
368         if (obj->type == OBJ_COMMIT)
369                 free_commit_buffer((struct commit *)obj);
370         return err;
371 }
372
373 static int fsck_obj_buffer(const struct object_id *oid, enum object_type type,
374                            unsigned long size, void *buffer, int *eaten)
375 {
376         /*
377          * Note, buffer may be NULL if type is OBJ_BLOB. See
378          * verify_packfile(), data_valid variable for details.
379          */
380         struct object *obj;
381         obj = parse_object_buffer(oid, type, size, buffer, eaten);
382         if (!obj) {
383                 errors_found |= ERROR_OBJECT;
384                 return error("%s: object corrupt or missing", oid_to_hex(oid));
385         }
386         obj->flags &= ~(REACHABLE | SEEN);
387         obj->flags |= HAS_OBJ;
388         return fsck_obj(obj);
389 }
390
391 static int default_refs;
392
393 static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
394         timestamp_t timestamp)
395 {
396         struct object *obj;
397
398         if (!is_null_oid(oid)) {
399                 obj = lookup_object(oid->hash);
400                 if (obj && (obj->flags & HAS_OBJ)) {
401                         if (timestamp && name_objects)
402                                 add_decoration(fsck_walk_options.object_names,
403                                         obj,
404                                         xstrfmt("%s@{%"PRItime"}", refname, timestamp));
405                         obj->flags |= USED;
406                         mark_object_reachable(obj);
407                 } else {
408                         error("%s: invalid reflog entry %s", refname, oid_to_hex(oid));
409                         errors_found |= ERROR_REACHABLE;
410                 }
411         }
412 }
413
414 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
415                 const char *email, timestamp_t timestamp, int tz,
416                 const char *message, void *cb_data)
417 {
418         const char *refname = cb_data;
419
420         if (verbose)
421                 fprintf(stderr, "Checking reflog %s->%s\n",
422                         oid_to_hex(ooid), oid_to_hex(noid));
423
424         fsck_handle_reflog_oid(refname, ooid, 0);
425         fsck_handle_reflog_oid(refname, noid, timestamp);
426         return 0;
427 }
428
429 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
430                               int flag, void *cb_data)
431 {
432         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
433         return 0;
434 }
435
436 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
437                            int flag, void *cb_data)
438 {
439         struct object *obj;
440
441         obj = parse_object(oid);
442         if (!obj) {
443                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
444                 errors_found |= ERROR_REACHABLE;
445                 /* We'll continue with the rest despite the error.. */
446                 return 0;
447         }
448         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
449                 error("%s: not a commit", refname);
450                 errors_found |= ERROR_REFS;
451         }
452         default_refs++;
453         obj->flags |= USED;
454         if (name_objects)
455                 add_decoration(fsck_walk_options.object_names,
456                         obj, xstrdup(refname));
457         mark_object_reachable(obj);
458
459         return 0;
460 }
461
462 static void get_default_heads(void)
463 {
464         if (head_points_at && !is_null_oid(&head_oid))
465                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
466         for_each_rawref(fsck_handle_ref, NULL);
467         if (include_reflogs)
468                 for_each_reflog(fsck_handle_reflog, NULL);
469
470         /*
471          * Not having any default heads isn't really fatal, but
472          * it does mean that "--unreachable" no longer makes any
473          * sense (since in this case everything will obviously
474          * be unreachable by definition.
475          *
476          * Showing dangling objects is valid, though (as those
477          * dangling objects are likely lost heads).
478          *
479          * So we just print a warning about it, and clear the
480          * "show_unreachable" flag.
481          */
482         if (!default_refs) {
483                 fprintf(stderr, "notice: No default references\n");
484                 show_unreachable = 0;
485         }
486 }
487
488 static struct object *parse_loose_object(const struct object_id *oid,
489                                          const char *path)
490 {
491         struct object *obj;
492         void *contents;
493         enum object_type type;
494         unsigned long size;
495         int eaten;
496
497         if (read_loose_object(path, oid->hash, &type, &size, &contents) < 0)
498                 return NULL;
499
500         if (!contents && type != OBJ_BLOB)
501                 die("BUG: read_loose_object streamed a non-blob");
502
503         obj = parse_object_buffer(oid, type, size, contents, &eaten);
504
505         if (!eaten)
506                 free(contents);
507         return obj;
508 }
509
510 static int fsck_loose(const struct object_id *oid, const char *path, void *data)
511 {
512         struct object *obj = parse_loose_object(oid, path);
513
514         if (!obj) {
515                 errors_found |= ERROR_OBJECT;
516                 error("%s: object corrupt or missing: %s",
517                       oid_to_hex(oid), path);
518                 return 0; /* keep checking other objects */
519         }
520
521         obj->flags &= ~(REACHABLE | SEEN);
522         obj->flags |= HAS_OBJ;
523         if (fsck_obj(obj))
524                 errors_found |= ERROR_OBJECT;
525         return 0;
526 }
527
528 static int fsck_cruft(const char *basename, const char *path, void *data)
529 {
530         if (!starts_with(basename, "tmp_obj_"))
531                 fprintf(stderr, "bad sha1 file: %s\n", path);
532         return 0;
533 }
534
535 static int fsck_subdir(unsigned int nr, const char *path, void *progress)
536 {
537         display_progress(progress, nr + 1);
538         return 0;
539 }
540
541 static void fsck_object_dir(const char *path)
542 {
543         struct progress *progress = NULL;
544
545         if (verbose)
546                 fprintf(stderr, "Checking object directory\n");
547
548         if (show_progress)
549                 progress = start_progress(_("Checking object directories"), 256);
550
551         for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
552                                       progress);
553         display_progress(progress, 256);
554         stop_progress(&progress);
555 }
556
557 static int fsck_head_link(void)
558 {
559         int null_is_error = 0;
560
561         if (verbose)
562                 fprintf(stderr, "Checking HEAD link\n");
563
564         head_points_at = resolve_ref_unsafe("HEAD", 0, &head_oid, NULL);
565         if (!head_points_at) {
566                 errors_found |= ERROR_REFS;
567                 return error("Invalid HEAD");
568         }
569         if (!strcmp(head_points_at, "HEAD"))
570                 /* detached HEAD */
571                 null_is_error = 1;
572         else if (!starts_with(head_points_at, "refs/heads/")) {
573                 errors_found |= ERROR_REFS;
574                 return error("HEAD points to something strange (%s)",
575                              head_points_at);
576         }
577         if (is_null_oid(&head_oid)) {
578                 if (null_is_error) {
579                         errors_found |= ERROR_REFS;
580                         return error("HEAD: detached HEAD points at nothing");
581                 }
582                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
583                         head_points_at + 11);
584         }
585         return 0;
586 }
587
588 static int fsck_cache_tree(struct cache_tree *it)
589 {
590         int i;
591         int err = 0;
592
593         if (verbose)
594                 fprintf(stderr, "Checking cache tree\n");
595
596         if (0 <= it->entry_count) {
597                 struct object *obj = parse_object(&it->oid);
598                 if (!obj) {
599                         error("%s: invalid sha1 pointer in cache-tree",
600                               oid_to_hex(&it->oid));
601                         errors_found |= ERROR_REFS;
602                         return 1;
603                 }
604                 obj->flags |= USED;
605                 if (name_objects)
606                         add_decoration(fsck_walk_options.object_names,
607                                 obj, xstrdup(":"));
608                 mark_object_reachable(obj);
609                 if (obj->type != OBJ_TREE)
610                         err |= objerror(obj, "non-tree in cache-tree");
611         }
612         for (i = 0; i < it->subtree_nr; i++)
613                 err |= fsck_cache_tree(it->down[i]->cache_tree);
614         return err;
615 }
616
617 static void mark_object_for_connectivity(const struct object_id *oid)
618 {
619         struct object *obj = lookup_unknown_object(oid->hash);
620         obj->flags |= HAS_OBJ;
621 }
622
623 static int mark_loose_for_connectivity(const struct object_id *oid,
624                                        const char *path,
625                                        void *data)
626 {
627         mark_object_for_connectivity(oid);
628         return 0;
629 }
630
631 static int mark_packed_for_connectivity(const struct object_id *oid,
632                                         struct packed_git *pack,
633                                         uint32_t pos,
634                                         void *data)
635 {
636         mark_object_for_connectivity(oid);
637         return 0;
638 }
639
640 static char const * const fsck_usage[] = {
641         N_("git fsck [<options>] [<object>...]"),
642         NULL
643 };
644
645 static struct option fsck_opts[] = {
646         OPT__VERBOSE(&verbose, N_("be verbose")),
647         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
648         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
649         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
650         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
651         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
652         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
653         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
654         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
655         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
656         OPT_BOOL(0, "lost-found", &write_lost_and_found,
657                                 N_("write dangling objects in .git/lost-found")),
658         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
659         OPT_BOOL(0, "name-objects", &name_objects, N_("show verbose names for reachable objects")),
660         OPT_END(),
661 };
662
663 int cmd_fsck(int argc, const char **argv, const char *prefix)
664 {
665         int i;
666         struct alternate_object_database *alt;
667
668         errors_found = 0;
669         check_replace_refs = 0;
670
671         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
672
673         fsck_walk_options.walk = mark_object;
674         fsck_obj_options.walk = mark_used;
675         fsck_obj_options.error_func = fsck_error_func;
676         if (check_strict)
677                 fsck_obj_options.strict = 1;
678
679         if (show_progress == -1)
680                 show_progress = isatty(2);
681         if (verbose)
682                 show_progress = 0;
683
684         if (write_lost_and_found) {
685                 check_full = 1;
686                 include_reflogs = 0;
687         }
688
689         if (name_objects)
690                 fsck_walk_options.object_names =
691                         xcalloc(1, sizeof(struct decoration));
692
693         git_config(fsck_config, NULL);
694
695         fsck_head_link();
696         if (connectivity_only) {
697                 for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
698                 for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
699         } else {
700                 fsck_object_dir(get_object_directory());
701
702                 prepare_alt_odb();
703                 for (alt = alt_odb_list; alt; alt = alt->next)
704                         fsck_object_dir(alt->path);
705
706                 if (check_full) {
707                         struct packed_git *p;
708                         uint32_t total = 0, count = 0;
709                         struct progress *progress = NULL;
710
711                         prepare_packed_git();
712
713                         if (show_progress) {
714                                 for (p = packed_git; p; p = p->next) {
715                                         if (open_pack_index(p))
716                                                 continue;
717                                         total += p->num_objects;
718                                 }
719
720                                 progress = start_progress(_("Checking objects"), total);
721                         }
722                         for (p = packed_git; p; p = p->next) {
723                                 /* verify gives error messages itself */
724                                 if (verify_pack(p, fsck_obj_buffer,
725                                                 progress, count))
726                                         errors_found |= ERROR_PACK;
727                                 count += p->num_objects;
728                         }
729                         stop_progress(&progress);
730                 }
731         }
732
733         for (i = 0; i < argc; i++) {
734                 const char *arg = argv[i];
735                 struct object_id oid;
736                 if (!get_oid(arg, &oid)) {
737                         struct object *obj = lookup_object(oid.hash);
738
739                         if (!obj || !(obj->flags & HAS_OBJ)) {
740                                 error("%s: object missing", oid_to_hex(&oid));
741                                 errors_found |= ERROR_OBJECT;
742                                 continue;
743                         }
744
745                         obj->flags |= USED;
746                         if (name_objects)
747                                 add_decoration(fsck_walk_options.object_names,
748                                         obj, xstrdup(arg));
749                         mark_object_reachable(obj);
750                         continue;
751                 }
752                 error("invalid parameter: expected sha1, got '%s'", arg);
753                 errors_found |= ERROR_OBJECT;
754         }
755
756         /*
757          * If we've not been given any explicit head information, do the
758          * default ones from .git/refs. We also consider the index file
759          * in this case (ie this implies --cache).
760          */
761         if (!argc) {
762                 get_default_heads();
763                 keep_cache_objects = 1;
764         }
765
766         if (keep_cache_objects) {
767                 verify_index_checksum = 1;
768                 verify_ce_order = 1;
769                 read_cache();
770                 for (i = 0; i < active_nr; i++) {
771                         unsigned int mode;
772                         struct blob *blob;
773                         struct object *obj;
774
775                         mode = active_cache[i]->ce_mode;
776                         if (S_ISGITLINK(mode))
777                                 continue;
778                         blob = lookup_blob(&active_cache[i]->oid);
779                         if (!blob)
780                                 continue;
781                         obj = &blob->object;
782                         obj->flags |= USED;
783                         if (name_objects)
784                                 add_decoration(fsck_walk_options.object_names,
785                                         obj,
786                                         xstrfmt(":%s", active_cache[i]->name));
787                         mark_object_reachable(obj);
788                 }
789                 if (active_cache_tree)
790                         fsck_cache_tree(active_cache_tree);
791         }
792
793         check_connectivity();
794         return errors_found;
795 }