index_has_changes(): avoid assuming operating on the_index
[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 = type_name(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" : type_name(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
153         if (is_promisor_object(&obj->oid))
154                 /*
155                  * Further recursion does not need to be performed on this
156                  * object since it is a promisor object (so it does not need to
157                  * be added to "pending").
158                  */
159                 return 0;
160
161         if (!(obj->flags & HAS_OBJ)) {
162                 if (parent && !has_object_file(&obj->oid)) {
163                         printf("broken link from %7s %s\n",
164                                  printable_type(parent), describe_object(parent));
165                         printf("              to %7s %s\n",
166                                  printable_type(obj), describe_object(obj));
167                         errors_found |= ERROR_REACHABLE;
168                 }
169                 return 1;
170         }
171
172         add_object_array(obj, NULL, &pending);
173         return 0;
174 }
175
176 static void mark_object_reachable(struct object *obj)
177 {
178         mark_object(obj, OBJ_ANY, NULL, NULL);
179 }
180
181 static int traverse_one_object(struct object *obj)
182 {
183         int result = fsck_walk(obj, obj, &fsck_walk_options);
184
185         if (obj->type == OBJ_TREE) {
186                 struct tree *tree = (struct tree *)obj;
187                 free_tree_buffer(tree);
188         }
189         return result;
190 }
191
192 static int traverse_reachable(void)
193 {
194         struct progress *progress = NULL;
195         unsigned int nr = 0;
196         int result = 0;
197         if (show_progress)
198                 progress = start_delayed_progress(_("Checking connectivity"), 0);
199         while (pending.nr) {
200                 result |= traverse_one_object(object_array_pop(&pending));
201                 display_progress(progress, ++nr);
202         }
203         stop_progress(&progress);
204         return !!result;
205 }
206
207 static int mark_used(struct object *obj, int type, void *data, struct fsck_options *options)
208 {
209         if (!obj)
210                 return 1;
211         obj->flags |= USED;
212         return 0;
213 }
214
215 /*
216  * Check a single reachable object
217  */
218 static void check_reachable_object(struct object *obj)
219 {
220         /*
221          * We obviously want the object to be parsed,
222          * except if it was in a pack-file and we didn't
223          * do a full fsck
224          */
225         if (!(obj->flags & HAS_OBJ)) {
226                 if (is_promisor_object(&obj->oid))
227                         return;
228                 if (has_sha1_pack(obj->oid.hash))
229                         return; /* it is in pack - forget about it */
230                 printf("missing %s %s\n", printable_type(obj),
231                         describe_object(obj));
232                 errors_found |= ERROR_REACHABLE;
233                 return;
234         }
235 }
236
237 /*
238  * Check a single unreachable object
239  */
240 static void check_unreachable_object(struct object *obj)
241 {
242         /*
243          * Missing unreachable object? Ignore it. It's not like
244          * we miss it (since it can't be reached), nor do we want
245          * to complain about it being unreachable (since it does
246          * not exist).
247          */
248         if (!(obj->flags & HAS_OBJ))
249                 return;
250
251         /*
252          * Unreachable object that exists? Show it if asked to,
253          * since this is something that is prunable.
254          */
255         if (show_unreachable) {
256                 printf("unreachable %s %s\n", printable_type(obj),
257                         describe_object(obj));
258                 return;
259         }
260
261         /*
262          * "!USED" means that nothing at all points to it, including
263          * other unreachable objects. In other words, it's the "tip"
264          * of some set of unreachable objects, usually a commit that
265          * got dropped.
266          *
267          * Such starting points are more interesting than some random
268          * set of unreachable objects, so we show them even if the user
269          * hasn't asked for _all_ unreachable objects. If you have
270          * deleted a branch by mistake, this is a prime candidate to
271          * start looking at, for example.
272          */
273         if (!(obj->flags & USED)) {
274                 if (show_dangling)
275                         printf("dangling %s %s\n", printable_type(obj),
276                                describe_object(obj));
277                 if (write_lost_and_found) {
278                         char *filename = git_pathdup("lost-found/%s/%s",
279                                 obj->type == OBJ_COMMIT ? "commit" : "other",
280                                 describe_object(obj));
281                         FILE *f;
282
283                         if (safe_create_leading_directories_const(filename)) {
284                                 error("Could not create lost-found");
285                                 free(filename);
286                                 return;
287                         }
288                         f = xfopen(filename, "w");
289                         if (obj->type == OBJ_BLOB) {
290                                 if (stream_blob_to_fd(fileno(f), &obj->oid, NULL, 1))
291                                         die_errno("Could not write '%s'", filename);
292                         } else
293                                 fprintf(f, "%s\n", describe_object(obj));
294                         if (fclose(f))
295                                 die_errno("Could not finish '%s'",
296                                           filename);
297                         free(filename);
298                 }
299                 return;
300         }
301
302         /*
303          * Otherwise? It's there, it's unreachable, and some other unreachable
304          * object points to it. Ignore it - it's not interesting, and we showed
305          * all the interesting cases above.
306          */
307 }
308
309 static void check_object(struct object *obj)
310 {
311         if (verbose)
312                 fprintf(stderr, "Checking %s\n", describe_object(obj));
313
314         if (obj->flags & REACHABLE)
315                 check_reachable_object(obj);
316         else
317                 check_unreachable_object(obj);
318 }
319
320 static void check_connectivity(void)
321 {
322         int i, max;
323
324         /* Traverse the pending reachable objects */
325         traverse_reachable();
326
327         /* Look up all the requirements, warn about missing objects.. */
328         max = get_max_object_index();
329         if (verbose)
330                 fprintf(stderr, "Checking connectivity (%d objects)\n", max);
331
332         for (i = 0; i < max; i++) {
333                 struct object *obj = get_indexed_object(i);
334
335                 if (obj)
336                         check_object(obj);
337         }
338 }
339
340 static int fsck_obj(struct object *obj, void *buffer, unsigned long size)
341 {
342         int err;
343
344         if (obj->flags & SEEN)
345                 return 0;
346         obj->flags |= SEEN;
347
348         if (verbose)
349                 fprintf(stderr, "Checking %s %s\n",
350                         printable_type(obj), describe_object(obj));
351
352         if (fsck_walk(obj, NULL, &fsck_obj_options))
353                 objerror(obj, "broken links");
354         err = fsck_object(obj, buffer, size, &fsck_obj_options);
355         if (err)
356                 goto out;
357
358         if (obj->type == OBJ_COMMIT) {
359                 struct commit *commit = (struct commit *) obj;
360
361                 if (!commit->parents && show_root)
362                         printf("root %s\n", describe_object(&commit->object));
363         }
364
365         if (obj->type == OBJ_TAG) {
366                 struct tag *tag = (struct tag *) obj;
367
368                 if (show_tags && tag->tagged) {
369                         printf("tagged %s %s", printable_type(tag->tagged),
370                                 describe_object(tag->tagged));
371                         printf(" (%s) in %s\n", tag->tag,
372                                 describe_object(&tag->object));
373                 }
374         }
375
376 out:
377         if (obj->type == OBJ_TREE)
378                 free_tree_buffer((struct tree *)obj);
379         if (obj->type == OBJ_COMMIT)
380                 free_commit_buffer((struct commit *)obj);
381         return err;
382 }
383
384 static int fsck_obj_buffer(const struct object_id *oid, enum object_type type,
385                            unsigned long size, void *buffer, int *eaten)
386 {
387         /*
388          * Note, buffer may be NULL if type is OBJ_BLOB. See
389          * verify_packfile(), data_valid variable for details.
390          */
391         struct object *obj;
392         obj = parse_object_buffer(oid, type, size, buffer, eaten);
393         if (!obj) {
394                 errors_found |= ERROR_OBJECT;
395                 return error("%s: object corrupt or missing", oid_to_hex(oid));
396         }
397         obj->flags &= ~(REACHABLE | SEEN);
398         obj->flags |= HAS_OBJ;
399         return fsck_obj(obj, buffer, size);
400 }
401
402 static int default_refs;
403
404 static void fsck_handle_reflog_oid(const char *refname, struct object_id *oid,
405         timestamp_t timestamp)
406 {
407         struct object *obj;
408
409         if (!is_null_oid(oid)) {
410                 obj = lookup_object(oid->hash);
411                 if (obj && (obj->flags & HAS_OBJ)) {
412                         if (timestamp && name_objects)
413                                 add_decoration(fsck_walk_options.object_names,
414                                         obj,
415                                         xstrfmt("%s@{%"PRItime"}", refname, timestamp));
416                         obj->flags |= USED;
417                         mark_object_reachable(obj);
418                 } else if (!is_promisor_object(oid)) {
419                         error("%s: invalid reflog entry %s", refname, oid_to_hex(oid));
420                         errors_found |= ERROR_REACHABLE;
421                 }
422         }
423 }
424
425 static int fsck_handle_reflog_ent(struct object_id *ooid, struct object_id *noid,
426                 const char *email, timestamp_t timestamp, int tz,
427                 const char *message, void *cb_data)
428 {
429         const char *refname = cb_data;
430
431         if (verbose)
432                 fprintf(stderr, "Checking reflog %s->%s\n",
433                         oid_to_hex(ooid), oid_to_hex(noid));
434
435         fsck_handle_reflog_oid(refname, ooid, 0);
436         fsck_handle_reflog_oid(refname, noid, timestamp);
437         return 0;
438 }
439
440 static int fsck_handle_reflog(const char *logname, const struct object_id *oid,
441                               int flag, void *cb_data)
442 {
443         for_each_reflog_ent(logname, fsck_handle_reflog_ent, (void *)logname);
444         return 0;
445 }
446
447 static int fsck_handle_ref(const char *refname, const struct object_id *oid,
448                            int flag, void *cb_data)
449 {
450         struct object *obj;
451
452         obj = parse_object(oid);
453         if (!obj) {
454                 if (is_promisor_object(oid)) {
455                         /*
456                          * Increment default_refs anyway, because this is a
457                          * valid ref.
458                          */
459                          default_refs++;
460                          return 0;
461                 }
462                 error("%s: invalid sha1 pointer %s", refname, oid_to_hex(oid));
463                 errors_found |= ERROR_REACHABLE;
464                 /* We'll continue with the rest despite the error.. */
465                 return 0;
466         }
467         if (obj->type != OBJ_COMMIT && is_branch(refname)) {
468                 error("%s: not a commit", refname);
469                 errors_found |= ERROR_REFS;
470         }
471         default_refs++;
472         obj->flags |= USED;
473         if (name_objects)
474                 add_decoration(fsck_walk_options.object_names,
475                         obj, xstrdup(refname));
476         mark_object_reachable(obj);
477
478         return 0;
479 }
480
481 static void get_default_heads(void)
482 {
483         if (head_points_at && !is_null_oid(&head_oid))
484                 fsck_handle_ref("HEAD", &head_oid, 0, NULL);
485         for_each_rawref(fsck_handle_ref, NULL);
486         if (include_reflogs)
487                 for_each_reflog(fsck_handle_reflog, NULL);
488
489         /*
490          * Not having any default heads isn't really fatal, but
491          * it does mean that "--unreachable" no longer makes any
492          * sense (since in this case everything will obviously
493          * be unreachable by definition.
494          *
495          * Showing dangling objects is valid, though (as those
496          * dangling objects are likely lost heads).
497          *
498          * So we just print a warning about it, and clear the
499          * "show_unreachable" flag.
500          */
501         if (!default_refs) {
502                 fprintf(stderr, "notice: No default references\n");
503                 show_unreachable = 0;
504         }
505 }
506
507 static int fsck_loose(const struct object_id *oid, const char *path, void *data)
508 {
509         struct object *obj;
510         enum object_type type;
511         unsigned long size;
512         void *contents;
513         int eaten;
514
515         if (read_loose_object(path, oid->hash, &type, &size, &contents) < 0) {
516                 errors_found |= ERROR_OBJECT;
517                 error("%s: object corrupt or missing: %s",
518                       oid_to_hex(oid), path);
519                 return 0; /* keep checking other objects */
520         }
521
522         if (!contents && type != OBJ_BLOB)
523                 BUG("read_loose_object streamed a non-blob");
524
525         obj = parse_object_buffer(oid, type, size, contents, &eaten);
526         if (!obj) {
527                 errors_found |= ERROR_OBJECT;
528                 error("%s: object could not be parsed: %s",
529                       oid_to_hex(oid), path);
530                 if (!eaten)
531                         free(contents);
532                 return 0; /* keep checking other objects */
533         }
534
535         obj->flags &= ~(REACHABLE | SEEN);
536         obj->flags |= HAS_OBJ;
537         if (fsck_obj(obj, contents, size))
538                 errors_found |= ERROR_OBJECT;
539
540         if (!eaten)
541                 free(contents);
542         return 0; /* keep checking other objects, even if we saw an error */
543 }
544
545 static int fsck_cruft(const char *basename, const char *path, void *data)
546 {
547         if (!starts_with(basename, "tmp_obj_"))
548                 fprintf(stderr, "bad sha1 file: %s\n", path);
549         return 0;
550 }
551
552 static int fsck_subdir(unsigned int nr, const char *path, void *progress)
553 {
554         display_progress(progress, nr + 1);
555         return 0;
556 }
557
558 static void fsck_object_dir(const char *path)
559 {
560         struct progress *progress = NULL;
561
562         if (verbose)
563                 fprintf(stderr, "Checking object directory\n");
564
565         if (show_progress)
566                 progress = start_progress(_("Checking object directories"), 256);
567
568         for_each_loose_file_in_objdir(path, fsck_loose, fsck_cruft, fsck_subdir,
569                                       progress);
570         display_progress(progress, 256);
571         stop_progress(&progress);
572 }
573
574 static int fsck_head_link(void)
575 {
576         int null_is_error = 0;
577
578         if (verbose)
579                 fprintf(stderr, "Checking HEAD link\n");
580
581         head_points_at = resolve_ref_unsafe("HEAD", 0, &head_oid, NULL);
582         if (!head_points_at) {
583                 errors_found |= ERROR_REFS;
584                 return error("Invalid HEAD");
585         }
586         if (!strcmp(head_points_at, "HEAD"))
587                 /* detached HEAD */
588                 null_is_error = 1;
589         else if (!starts_with(head_points_at, "refs/heads/")) {
590                 errors_found |= ERROR_REFS;
591                 return error("HEAD points to something strange (%s)",
592                              head_points_at);
593         }
594         if (is_null_oid(&head_oid)) {
595                 if (null_is_error) {
596                         errors_found |= ERROR_REFS;
597                         return error("HEAD: detached HEAD points at nothing");
598                 }
599                 fprintf(stderr, "notice: HEAD points to an unborn branch (%s)\n",
600                         head_points_at + 11);
601         }
602         return 0;
603 }
604
605 static int fsck_cache_tree(struct cache_tree *it)
606 {
607         int i;
608         int err = 0;
609
610         if (verbose)
611                 fprintf(stderr, "Checking cache tree\n");
612
613         if (0 <= it->entry_count) {
614                 struct object *obj = parse_object(&it->oid);
615                 if (!obj) {
616                         error("%s: invalid sha1 pointer in cache-tree",
617                               oid_to_hex(&it->oid));
618                         errors_found |= ERROR_REFS;
619                         return 1;
620                 }
621                 obj->flags |= USED;
622                 if (name_objects)
623                         add_decoration(fsck_walk_options.object_names,
624                                 obj, xstrdup(":"));
625                 mark_object_reachable(obj);
626                 if (obj->type != OBJ_TREE)
627                         err |= objerror(obj, "non-tree in cache-tree");
628         }
629         for (i = 0; i < it->subtree_nr; i++)
630                 err |= fsck_cache_tree(it->down[i]->cache_tree);
631         return err;
632 }
633
634 static void mark_object_for_connectivity(const struct object_id *oid)
635 {
636         struct object *obj = lookup_unknown_object(oid->hash);
637         obj->flags |= HAS_OBJ;
638 }
639
640 static int mark_loose_for_connectivity(const struct object_id *oid,
641                                        const char *path,
642                                        void *data)
643 {
644         mark_object_for_connectivity(oid);
645         return 0;
646 }
647
648 static int mark_packed_for_connectivity(const struct object_id *oid,
649                                         struct packed_git *pack,
650                                         uint32_t pos,
651                                         void *data)
652 {
653         mark_object_for_connectivity(oid);
654         return 0;
655 }
656
657 static char const * const fsck_usage[] = {
658         N_("git fsck [<options>] [<object>...]"),
659         NULL
660 };
661
662 static struct option fsck_opts[] = {
663         OPT__VERBOSE(&verbose, N_("be verbose")),
664         OPT_BOOL(0, "unreachable", &show_unreachable, N_("show unreachable objects")),
665         OPT_BOOL(0, "dangling", &show_dangling, N_("show dangling objects")),
666         OPT_BOOL(0, "tags", &show_tags, N_("report tags")),
667         OPT_BOOL(0, "root", &show_root, N_("report root nodes")),
668         OPT_BOOL(0, "cache", &keep_cache_objects, N_("make index objects head nodes")),
669         OPT_BOOL(0, "reflogs", &include_reflogs, N_("make reflogs head nodes (default)")),
670         OPT_BOOL(0, "full", &check_full, N_("also consider packs and alternate objects")),
671         OPT_BOOL(0, "connectivity-only", &connectivity_only, N_("check only connectivity")),
672         OPT_BOOL(0, "strict", &check_strict, N_("enable more strict checking")),
673         OPT_BOOL(0, "lost-found", &write_lost_and_found,
674                                 N_("write dangling objects in .git/lost-found")),
675         OPT_BOOL(0, "progress", &show_progress, N_("show progress")),
676         OPT_BOOL(0, "name-objects", &name_objects, N_("show verbose names for reachable objects")),
677         OPT_END(),
678 };
679
680 int cmd_fsck(int argc, const char **argv, const char *prefix)
681 {
682         int i;
683         struct alternate_object_database *alt;
684
685         /* fsck knows how to handle missing promisor objects */
686         fetch_if_missing = 0;
687
688         errors_found = 0;
689         check_replace_refs = 0;
690
691         argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
692
693         fsck_walk_options.walk = mark_object;
694         fsck_obj_options.walk = mark_used;
695         fsck_obj_options.error_func = fsck_error_func;
696         if (check_strict)
697                 fsck_obj_options.strict = 1;
698
699         if (show_progress == -1)
700                 show_progress = isatty(2);
701         if (verbose)
702                 show_progress = 0;
703
704         if (write_lost_and_found) {
705                 check_full = 1;
706                 include_reflogs = 0;
707         }
708
709         if (name_objects)
710                 fsck_walk_options.object_names =
711                         xcalloc(1, sizeof(struct decoration));
712
713         git_config(fsck_config, NULL);
714
715         fsck_head_link();
716         if (connectivity_only) {
717                 for_each_loose_object(mark_loose_for_connectivity, NULL, 0);
718                 for_each_packed_object(mark_packed_for_connectivity, NULL, 0);
719         } else {
720                 fsck_object_dir(get_object_directory());
721
722                 prepare_alt_odb();
723                 for (alt = alt_odb_list; alt; alt = alt->next)
724                         fsck_object_dir(alt->path);
725
726                 if (check_full) {
727                         struct packed_git *p;
728                         uint32_t total = 0, count = 0;
729                         struct progress *progress = NULL;
730
731                         prepare_packed_git();
732
733                         if (show_progress) {
734                                 for (p = packed_git; p; p = p->next) {
735                                         if (open_pack_index(p))
736                                                 continue;
737                                         total += p->num_objects;
738                                 }
739
740                                 progress = start_progress(_("Checking objects"), total);
741                         }
742                         for (p = packed_git; p; p = p->next) {
743                                 /* verify gives error messages itself */
744                                 if (verify_pack(p, fsck_obj_buffer,
745                                                 progress, count))
746                                         errors_found |= ERROR_PACK;
747                                 count += p->num_objects;
748                         }
749                         stop_progress(&progress);
750                 }
751
752                 if (fsck_finish(&fsck_obj_options))
753                         errors_found |= ERROR_OBJECT;
754         }
755
756         for (i = 0; i < argc; i++) {
757                 const char *arg = argv[i];
758                 struct object_id oid;
759                 if (!get_oid(arg, &oid)) {
760                         struct object *obj = lookup_object(oid.hash);
761
762                         if (!obj || !(obj->flags & HAS_OBJ)) {
763                                 if (is_promisor_object(&oid))
764                                         continue;
765                                 error("%s: object missing", oid_to_hex(&oid));
766                                 errors_found |= ERROR_OBJECT;
767                                 continue;
768                         }
769
770                         obj->flags |= USED;
771                         if (name_objects)
772                                 add_decoration(fsck_walk_options.object_names,
773                                         obj, xstrdup(arg));
774                         mark_object_reachable(obj);
775                         continue;
776                 }
777                 error("invalid parameter: expected sha1, got '%s'", arg);
778                 errors_found |= ERROR_OBJECT;
779         }
780
781         /*
782          * If we've not been given any explicit head information, do the
783          * default ones from .git/refs. We also consider the index file
784          * in this case (ie this implies --cache).
785          */
786         if (!argc) {
787                 get_default_heads();
788                 keep_cache_objects = 1;
789         }
790
791         if (keep_cache_objects) {
792                 verify_index_checksum = 1;
793                 verify_ce_order = 1;
794                 read_cache();
795                 for (i = 0; i < active_nr; i++) {
796                         unsigned int mode;
797                         struct blob *blob;
798                         struct object *obj;
799
800                         mode = active_cache[i]->ce_mode;
801                         if (S_ISGITLINK(mode))
802                                 continue;
803                         blob = lookup_blob(&active_cache[i]->oid);
804                         if (!blob)
805                                 continue;
806                         obj = &blob->object;
807                         obj->flags |= USED;
808                         if (name_objects)
809                                 add_decoration(fsck_walk_options.object_names,
810                                         obj,
811                                         xstrfmt(":%s", active_cache[i]->name));
812                         mark_object_reachable(obj);
813                 }
814                 if (active_cache_tree)
815                         fsck_cache_tree(active_cache_tree);
816         }
817
818         check_connectivity();
819         return errors_found;
820 }