Start draft release notes for 1.6.0.3
[git/dscho.git] / builtin-fetch-pack.c
blob85509f5ee5884589980c9a1c5f96b66a3d49d5dd
1 #include "cache.h"
2 #include "refs.h"
3 #include "pkt-line.h"
4 #include "commit.h"
5 #include "tag.h"
6 #include "exec_cmd.h"
7 #include "pack.h"
8 #include "sideband.h"
9 #include "fetch-pack.h"
10 #include "remote.h"
11 #include "run-command.h"
13 static int transfer_unpack_limit = -1;
14 static int fetch_unpack_limit = -1;
15 static int unpack_limit = 100;
16 static struct fetch_pack_args args = {
17         /* .uploadpack = */ "git-upload-pack",
20 static const char fetch_pack_usage[] =
21 "git fetch-pack [--all] [--quiet|-q] [--keep|-k] [--thin] [--include-tag] [--upload-pack=<git-upload-pack>] [--depth=<n>] [--no-progress] [-v] [<host>:]<directory> [<refs>...]";
23 #define COMPLETE        (1U << 0)
24 #define COMMON          (1U << 1)
25 #define COMMON_REF      (1U << 2)
26 #define SEEN            (1U << 3)
27 #define POPPED          (1U << 4)
29 static int marked;
32  * After sending this many "have"s if we do not get any new ACK , we
33  * give up traversing our history.
34  */
35 #define MAX_IN_VAIN 256
37 static struct commit_list *rev_list;
38 static int non_common_revs, multi_ack, use_sideband;
40 static void rev_list_push(struct commit *commit, int mark)
42         if (!(commit->object.flags & mark)) {
43                 commit->object.flags |= mark;
45                 if (!(commit->object.parsed))
46                         if (parse_commit(commit))
47                                 return;
49                 insert_by_date(commit, &rev_list);
51                 if (!(commit->object.flags & COMMON))
52                         non_common_revs++;
53         }
56 static int rev_list_insert_ref(const char *path, const unsigned char *sha1, int flag, void *cb_data)
58         struct object *o = deref_tag(parse_object(sha1), path, 0);
60         if (o && o->type == OBJ_COMMIT)
61                 rev_list_push((struct commit *)o, SEEN);
63         return 0;
66 static int clear_marks(const char *path, const unsigned char *sha1, int flag, void *cb_data)
68         struct object *o = deref_tag(parse_object(sha1), path, 0);
70         if (o && o->type == OBJ_COMMIT)
71                 clear_commit_marks((struct commit *)o,
72                                    COMMON | COMMON_REF | SEEN | POPPED);
73         return 0;
77    This function marks a rev and its ancestors as common.
78    In some cases, it is desirable to mark only the ancestors (for example
79    when only the server does not yet know that they are common).
82 static void mark_common(struct commit *commit,
83                 int ancestors_only, int dont_parse)
85         if (commit != NULL && !(commit->object.flags & COMMON)) {
86                 struct object *o = (struct object *)commit;
88                 if (!ancestors_only)
89                         o->flags |= COMMON;
91                 if (!(o->flags & SEEN))
92                         rev_list_push(commit, SEEN);
93                 else {
94                         struct commit_list *parents;
96                         if (!ancestors_only && !(o->flags & POPPED))
97                                 non_common_revs--;
98                         if (!o->parsed && !dont_parse)
99                                 if (parse_commit(commit))
100                                         return;
102                         for (parents = commit->parents;
103                                         parents;
104                                         parents = parents->next)
105                                 mark_common(parents->item, 0, dont_parse);
106                 }
107         }
111   Get the next rev to send, ignoring the common.
114 static const unsigned char* get_rev(void)
116         struct commit *commit = NULL;
118         while (commit == NULL) {
119                 unsigned int mark;
120                 struct commit_list *parents;
122                 if (rev_list == NULL || non_common_revs == 0)
123                         return NULL;
125                 commit = rev_list->item;
126                 if (!commit->object.parsed)
127                         parse_commit(commit);
128                 parents = commit->parents;
130                 commit->object.flags |= POPPED;
131                 if (!(commit->object.flags & COMMON))
132                         non_common_revs--;
134                 if (commit->object.flags & COMMON) {
135                         /* do not send "have", and ignore ancestors */
136                         commit = NULL;
137                         mark = COMMON | SEEN;
138                 } else if (commit->object.flags & COMMON_REF)
139                         /* send "have", and ignore ancestors */
140                         mark = COMMON | SEEN;
141                 else
142                         /* send "have", also for its ancestors */
143                         mark = SEEN;
145                 while (parents) {
146                         if (!(parents->item->object.flags & SEEN))
147                                 rev_list_push(parents->item, mark);
148                         if (mark & COMMON)
149                                 mark_common(parents->item, 1, 0);
150                         parents = parents->next;
151                 }
153                 rev_list = rev_list->next;
154         }
156         return commit->object.sha1;
159 static int find_common(int fd[2], unsigned char *result_sha1,
160                        struct ref *refs)
162         int fetching;
163         int count = 0, flushes = 0, retval;
164         const unsigned char *sha1;
165         unsigned in_vain = 0;
166         int got_continue = 0;
168         if (marked)
169                 for_each_ref(clear_marks, NULL);
170         marked = 1;
172         for_each_ref(rev_list_insert_ref, NULL);
174         fetching = 0;
175         for ( ; refs ; refs = refs->next) {
176                 unsigned char *remote = refs->old_sha1;
177                 struct object *o;
179                 /*
180                  * If that object is complete (i.e. it is an ancestor of a
181                  * local ref), we tell them we have it but do not have to
182                  * tell them about its ancestors, which they already know
183                  * about.
184                  *
185                  * We use lookup_object here because we are only
186                  * interested in the case we *know* the object is
187                  * reachable and we have already scanned it.
188                  */
189                 if (((o = lookup_object(remote)) != NULL) &&
190                                 (o->flags & COMPLETE)) {
191                         continue;
192                 }
194                 if (!fetching)
195                         packet_write(fd[1], "want %s%s%s%s%s%s%s%s\n",
196                                      sha1_to_hex(remote),
197                                      (multi_ack ? " multi_ack" : ""),
198                                      (use_sideband == 2 ? " side-band-64k" : ""),
199                                      (use_sideband == 1 ? " side-band" : ""),
200                                      (args.use_thin_pack ? " thin-pack" : ""),
201                                      (args.no_progress ? " no-progress" : ""),
202                                      (args.include_tag ? " include-tag" : ""),
203                                      " ofs-delta");
204                 else
205                         packet_write(fd[1], "want %s\n", sha1_to_hex(remote));
206                 fetching++;
207         }
208         if (is_repository_shallow())
209                 write_shallow_commits(fd[1], 1);
210         if (args.depth > 0)
211                 packet_write(fd[1], "deepen %d", args.depth);
212         packet_flush(fd[1]);
213         if (!fetching)
214                 return 1;
216         if (args.depth > 0) {
217                 char line[1024];
218                 unsigned char sha1[20];
219                 int len;
221                 while ((len = packet_read_line(fd[0], line, sizeof(line)))) {
222                         if (!prefixcmp(line, "shallow ")) {
223                                 if (get_sha1_hex(line + 8, sha1))
224                                         die("invalid shallow line: %s", line);
225                                 register_shallow(sha1);
226                                 continue;
227                         }
228                         if (!prefixcmp(line, "unshallow ")) {
229                                 if (get_sha1_hex(line + 10, sha1))
230                                         die("invalid unshallow line: %s", line);
231                                 if (!lookup_object(sha1))
232                                         die("object not found: %s", line);
233                                 /* make sure that it is parsed as shallow */
234                                 if (!parse_object(sha1))
235                                         die("error in object: %s", line);
236                                 if (unregister_shallow(sha1))
237                                         die("no shallow found: %s", line);
238                                 continue;
239                         }
240                         die("expected shallow/unshallow, got %s", line);
241                 }
242         }
244         flushes = 0;
245         retval = -1;
246         while ((sha1 = get_rev())) {
247                 packet_write(fd[1], "have %s\n", sha1_to_hex(sha1));
248                 if (args.verbose)
249                         fprintf(stderr, "have %s\n", sha1_to_hex(sha1));
250                 in_vain++;
251                 if (!(31 & ++count)) {
252                         int ack;
254                         packet_flush(fd[1]);
255                         flushes++;
257                         /*
258                          * We keep one window "ahead" of the other side, and
259                          * will wait for an ACK only on the next one
260                          */
261                         if (count == 32)
262                                 continue;
264                         do {
265                                 ack = get_ack(fd[0], result_sha1);
266                                 if (args.verbose && ack)
267                                         fprintf(stderr, "got ack %d %s\n", ack,
268                                                         sha1_to_hex(result_sha1));
269                                 if (ack == 1) {
270                                         flushes = 0;
271                                         multi_ack = 0;
272                                         retval = 0;
273                                         goto done;
274                                 } else if (ack == 2) {
275                                         struct commit *commit =
276                                                 lookup_commit(result_sha1);
277                                         mark_common(commit, 0, 1);
278                                         retval = 0;
279                                         in_vain = 0;
280                                         got_continue = 1;
281                                 }
282                         } while (ack);
283                         flushes--;
284                         if (got_continue && MAX_IN_VAIN < in_vain) {
285                                 if (args.verbose)
286                                         fprintf(stderr, "giving up\n");
287                                 break; /* give up */
288                         }
289                 }
290         }
291 done:
292         packet_write(fd[1], "done\n");
293         if (args.verbose)
294                 fprintf(stderr, "done\n");
295         if (retval != 0) {
296                 multi_ack = 0;
297                 flushes++;
298         }
299         while (flushes || multi_ack) {
300                 int ack = get_ack(fd[0], result_sha1);
301                 if (ack) {
302                         if (args.verbose)
303                                 fprintf(stderr, "got ack (%d) %s\n", ack,
304                                         sha1_to_hex(result_sha1));
305                         if (ack == 1)
306                                 return 0;
307                         multi_ack = 1;
308                         continue;
309                 }
310                 flushes--;
311         }
312         /* it is no error to fetch into a completely empty repo */
313         return count ? retval : 0;
316 static struct commit_list *complete;
318 static int mark_complete(const char *path, const unsigned char *sha1, int flag, void *cb_data)
320         struct object *o = parse_object(sha1);
322         while (o && o->type == OBJ_TAG) {
323                 struct tag *t = (struct tag *) o;
324                 if (!t->tagged)
325                         break; /* broken repository */
326                 o->flags |= COMPLETE;
327                 o = parse_object(t->tagged->sha1);
328         }
329         if (o && o->type == OBJ_COMMIT) {
330                 struct commit *commit = (struct commit *)o;
331                 commit->object.flags |= COMPLETE;
332                 insert_by_date(commit, &complete);
333         }
334         return 0;
337 static void mark_recent_complete_commits(unsigned long cutoff)
339         while (complete && cutoff <= complete->item->date) {
340                 if (args.verbose)
341                         fprintf(stderr, "Marking %s as complete\n",
342                                 sha1_to_hex(complete->item->object.sha1));
343                 pop_most_recent_commit(&complete, COMPLETE);
344         }
347 static void filter_refs(struct ref **refs, int nr_match, char **match)
349         struct ref **return_refs;
350         struct ref *newlist = NULL;
351         struct ref **newtail = &newlist;
352         struct ref *ref, *next;
353         struct ref *fastarray[32];
355         if (nr_match && !args.fetch_all) {
356                 if (ARRAY_SIZE(fastarray) < nr_match)
357                         return_refs = xcalloc(nr_match, sizeof(struct ref *));
358                 else {
359                         return_refs = fastarray;
360                         memset(return_refs, 0, sizeof(struct ref *) * nr_match);
361                 }
362         }
363         else
364                 return_refs = NULL;
366         for (ref = *refs; ref; ref = next) {
367                 next = ref->next;
368                 if (!memcmp(ref->name, "refs/", 5) &&
369                     check_ref_format(ref->name + 5))
370                         ; /* trash */
371                 else if (args.fetch_all &&
372                          (!args.depth || prefixcmp(ref->name, "refs/tags/") )) {
373                         *newtail = ref;
374                         ref->next = NULL;
375                         newtail = &ref->next;
376                         continue;
377                 }
378                 else {
379                         int order = path_match(ref->name, nr_match, match);
380                         if (order) {
381                                 return_refs[order-1] = ref;
382                                 continue; /* we will link it later */
383                         }
384                 }
385                 free(ref);
386         }
388         if (!args.fetch_all) {
389                 int i;
390                 for (i = 0; i < nr_match; i++) {
391                         ref = return_refs[i];
392                         if (ref) {
393                                 *newtail = ref;
394                                 ref->next = NULL;
395                                 newtail = &ref->next;
396                         }
397                 }
398                 if (return_refs != fastarray)
399                         free(return_refs);
400         }
401         *refs = newlist;
404 static int everything_local(struct ref **refs, int nr_match, char **match)
406         struct ref *ref;
407         int retval;
408         unsigned long cutoff = 0;
410         save_commit_buffer = 0;
412         for (ref = *refs; ref; ref = ref->next) {
413                 struct object *o;
415                 o = parse_object(ref->old_sha1);
416                 if (!o)
417                         continue;
419                 /* We already have it -- which may mean that we were
420                  * in sync with the other side at some time after
421                  * that (it is OK if we guess wrong here).
422                  */
423                 if (o->type == OBJ_COMMIT) {
424                         struct commit *commit = (struct commit *)o;
425                         if (!cutoff || cutoff < commit->date)
426                                 cutoff = commit->date;
427                 }
428         }
430         if (!args.depth) {
431                 for_each_ref(mark_complete, NULL);
432                 if (cutoff)
433                         mark_recent_complete_commits(cutoff);
434         }
436         /*
437          * Mark all complete remote refs as common refs.
438          * Don't mark them common yet; the server has to be told so first.
439          */
440         for (ref = *refs; ref; ref = ref->next) {
441                 struct object *o = deref_tag(lookup_object(ref->old_sha1),
442                                              NULL, 0);
444                 if (!o || o->type != OBJ_COMMIT || !(o->flags & COMPLETE))
445                         continue;
447                 if (!(o->flags & SEEN)) {
448                         rev_list_push((struct commit *)o, COMMON_REF | SEEN);
450                         mark_common((struct commit *)o, 1, 1);
451                 }
452         }
454         filter_refs(refs, nr_match, match);
456         for (retval = 1, ref = *refs; ref ; ref = ref->next) {
457                 const unsigned char *remote = ref->old_sha1;
458                 unsigned char local[20];
459                 struct object *o;
461                 o = lookup_object(remote);
462                 if (!o || !(o->flags & COMPLETE)) {
463                         retval = 0;
464                         if (!args.verbose)
465                                 continue;
466                         fprintf(stderr,
467                                 "want %s (%s)\n", sha1_to_hex(remote),
468                                 ref->name);
469                         continue;
470                 }
472                 hashcpy(ref->new_sha1, local);
473                 if (!args.verbose)
474                         continue;
475                 fprintf(stderr,
476                         "already have %s (%s)\n", sha1_to_hex(remote),
477                         ref->name);
478         }
479         return retval;
482 static int sideband_demux(int fd, void *data)
484         int *xd = data;
486         return recv_sideband("fetch-pack", xd[0], fd, 2);
489 static int get_pack(int xd[2], char **pack_lockfile)
491         struct async demux;
492         const char *argv[20];
493         char keep_arg[256];
494         char hdr_arg[256];
495         const char **av;
496         int do_keep = args.keep_pack;
497         struct child_process cmd;
499         memset(&demux, 0, sizeof(demux));
500         if (use_sideband) {
501                 /* xd[] is talking with upload-pack; subprocess reads from
502                  * xd[0], spits out band#2 to stderr, and feeds us band#1
503                  * through demux->out.
504                  */
505                 demux.proc = sideband_demux;
506                 demux.data = xd;
507                 if (start_async(&demux))
508                         die("fetch-pack: unable to fork off sideband"
509                             " demultiplexer");
510         }
511         else
512                 demux.out = xd[0];
514         memset(&cmd, 0, sizeof(cmd));
515         cmd.argv = argv;
516         av = argv;
517         *hdr_arg = 0;
518         if (!args.keep_pack && unpack_limit) {
519                 struct pack_header header;
521                 if (read_pack_header(demux.out, &header))
522                         die("protocol error: bad pack header");
523                 snprintf(hdr_arg, sizeof(hdr_arg),
524                          "--pack_header=%"PRIu32",%"PRIu32,
525                          ntohl(header.hdr_version), ntohl(header.hdr_entries));
526                 if (ntohl(header.hdr_entries) < unpack_limit)
527                         do_keep = 0;
528                 else
529                         do_keep = 1;
530         }
532         if (do_keep) {
533                 if (pack_lockfile)
534                         cmd.out = -1;
535                 *av++ = "index-pack";
536                 *av++ = "--stdin";
537                 if (!args.quiet && !args.no_progress)
538                         *av++ = "-v";
539                 if (args.use_thin_pack)
540                         *av++ = "--fix-thin";
541                 if (args.lock_pack || unpack_limit) {
542                         int s = sprintf(keep_arg,
543                                         "--keep=fetch-pack %d on ", getpid());
544                         if (gethostname(keep_arg + s, sizeof(keep_arg) - s))
545                                 strcpy(keep_arg + s, "localhost");
546                         *av++ = keep_arg;
547                 }
548         }
549         else {
550                 *av++ = "unpack-objects";
551                 if (args.quiet)
552                         *av++ = "-q";
553         }
554         if (*hdr_arg)
555                 *av++ = hdr_arg;
556         *av++ = NULL;
558         cmd.in = demux.out;
559         cmd.git_cmd = 1;
560         if (start_command(&cmd))
561                 die("fetch-pack: unable to fork off %s", argv[0]);
562         if (do_keep && pack_lockfile) {
563                 *pack_lockfile = index_pack_lockfile(cmd.out);
564                 close(cmd.out);
565         }
567         if (finish_command(&cmd))
568                 die("%s failed", argv[0]);
569         if (use_sideband && finish_async(&demux))
570                 die("error in sideband demultiplexer");
571         return 0;
574 static struct ref *do_fetch_pack(int fd[2],
575                 const struct ref *orig_ref,
576                 int nr_match,
577                 char **match,
578                 char **pack_lockfile)
580         struct ref *ref = copy_ref_list(orig_ref);
581         unsigned char sha1[20];
583         if (is_repository_shallow() && !server_supports("shallow"))
584                 die("Server does not support shallow clients");
585         if (server_supports("multi_ack")) {
586                 if (args.verbose)
587                         fprintf(stderr, "Server supports multi_ack\n");
588                 multi_ack = 1;
589         }
590         if (server_supports("side-band-64k")) {
591                 if (args.verbose)
592                         fprintf(stderr, "Server supports side-band-64k\n");
593                 use_sideband = 2;
594         }
595         else if (server_supports("side-band")) {
596                 if (args.verbose)
597                         fprintf(stderr, "Server supports side-band\n");
598                 use_sideband = 1;
599         }
600         if (everything_local(&ref, nr_match, match)) {
601                 packet_flush(fd[1]);
602                 goto all_done;
603         }
604         if (find_common(fd, sha1, ref) < 0)
605                 if (!args.keep_pack)
606                         /* When cloning, it is not unusual to have
607                          * no common commit.
608                          */
609                         fprintf(stderr, "warning: no common commits\n");
611         if (get_pack(fd, pack_lockfile))
612                 die("git fetch-pack: fetch failed.");
614  all_done:
615         return ref;
618 static int remove_duplicates(int nr_heads, char **heads)
620         int src, dst;
622         for (src = dst = 0; src < nr_heads; src++) {
623                 /* If heads[src] is different from any of
624                  * heads[0..dst], push it in.
625                  */
626                 int i;
627                 for (i = 0; i < dst; i++) {
628                         if (!strcmp(heads[i], heads[src]))
629                                 break;
630                 }
631                 if (i < dst)
632                         continue;
633                 if (src != dst)
634                         heads[dst] = heads[src];
635                 dst++;
636         }
637         return dst;
640 static int fetch_pack_config(const char *var, const char *value, void *cb)
642         if (strcmp(var, "fetch.unpacklimit") == 0) {
643                 fetch_unpack_limit = git_config_int(var, value);
644                 return 0;
645         }
647         if (strcmp(var, "transfer.unpacklimit") == 0) {
648                 transfer_unpack_limit = git_config_int(var, value);
649                 return 0;
650         }
652         return git_default_config(var, value, cb);
655 static struct lock_file lock;
657 static void fetch_pack_setup(void)
659         static int did_setup;
660         if (did_setup)
661                 return;
662         git_config(fetch_pack_config, NULL);
663         if (0 <= transfer_unpack_limit)
664                 unpack_limit = transfer_unpack_limit;
665         else if (0 <= fetch_unpack_limit)
666                 unpack_limit = fetch_unpack_limit;
667         did_setup = 1;
670 int cmd_fetch_pack(int argc, const char **argv, const char *prefix)
672         int i, ret, nr_heads;
673         struct ref *ref = NULL;
674         char *dest = NULL, **heads;
675         int fd[2];
676         struct child_process *conn;
678         nr_heads = 0;
679         heads = NULL;
680         for (i = 1; i < argc; i++) {
681                 const char *arg = argv[i];
683                 if (*arg == '-') {
684                         if (!prefixcmp(arg, "--upload-pack=")) {
685                                 args.uploadpack = arg + 14;
686                                 continue;
687                         }
688                         if (!prefixcmp(arg, "--exec=")) {
689                                 args.uploadpack = arg + 7;
690                                 continue;
691                         }
692                         if (!strcmp("--quiet", arg) || !strcmp("-q", arg)) {
693                                 args.quiet = 1;
694                                 continue;
695                         }
696                         if (!strcmp("--keep", arg) || !strcmp("-k", arg)) {
697                                 args.lock_pack = args.keep_pack;
698                                 args.keep_pack = 1;
699                                 continue;
700                         }
701                         if (!strcmp("--thin", arg)) {
702                                 args.use_thin_pack = 1;
703                                 continue;
704                         }
705                         if (!strcmp("--include-tag", arg)) {
706                                 args.include_tag = 1;
707                                 continue;
708                         }
709                         if (!strcmp("--all", arg)) {
710                                 args.fetch_all = 1;
711                                 continue;
712                         }
713                         if (!strcmp("-v", arg)) {
714                                 args.verbose = 1;
715                                 continue;
716                         }
717                         if (!prefixcmp(arg, "--depth=")) {
718                                 args.depth = strtol(arg + 8, NULL, 0);
719                                 continue;
720                         }
721                         if (!strcmp("--no-progress", arg)) {
722                                 args.no_progress = 1;
723                                 continue;
724                         }
725                         usage(fetch_pack_usage);
726                 }
727                 dest = (char *)arg;
728                 heads = (char **)(argv + i + 1);
729                 nr_heads = argc - i - 1;
730                 break;
731         }
732         if (!dest)
733                 usage(fetch_pack_usage);
735         conn = git_connect(fd, (char *)dest, args.uploadpack,
736                            args.verbose ? CONNECT_VERBOSE : 0);
737         if (conn) {
738                 get_remote_heads(fd[0], &ref, 0, NULL, 0);
740                 ref = fetch_pack(&args, fd, conn, ref, dest, nr_heads, heads, NULL);
741                 close(fd[0]);
742                 close(fd[1]);
743                 if (finish_connect(conn))
744                         ref = NULL;
745         } else {
746                 ref = NULL;
747         }
748         ret = !ref;
750         if (!ret && nr_heads) {
751                 /* If the heads to pull were given, we should have
752                  * consumed all of them by matching the remote.
753                  * Otherwise, 'git fetch remote no-such-ref' would
754                  * silently succeed without issuing an error.
755                  */
756                 for (i = 0; i < nr_heads; i++)
757                         if (heads[i] && heads[i][0]) {
758                                 error("no such remote ref %s", heads[i]);
759                                 ret = 1;
760                         }
761         }
762         while (ref) {
763                 printf("%s %s\n",
764                        sha1_to_hex(ref->old_sha1), ref->name);
765                 ref = ref->next;
766         }
768         return ret;
771 struct ref *fetch_pack(struct fetch_pack_args *my_args,
772                        int fd[], struct child_process *conn,
773                        const struct ref *ref,
774                 const char *dest,
775                 int nr_heads,
776                 char **heads,
777                 char **pack_lockfile)
779         struct stat st;
780         struct ref *ref_cpy;
782         fetch_pack_setup();
783         memcpy(&args, my_args, sizeof(args));
784         if (args.depth > 0) {
785                 if (stat(git_path("shallow"), &st))
786                         st.st_mtime = 0;
787         }
789         if (heads && nr_heads)
790                 nr_heads = remove_duplicates(nr_heads, heads);
791         if (!ref) {
792                 packet_flush(fd[1]);
793                 die("no matching remote head");
794         }
795         ref_cpy = do_fetch_pack(fd, ref, nr_heads, heads, pack_lockfile);
797         if (args.depth > 0) {
798                 struct cache_time mtime;
799                 char *shallow = git_path("shallow");
800                 int fd;
802                 mtime.sec = st.st_mtime;
803 #ifdef USE_NSEC
804                 mtime.usec = st.st_mtim.usec;
805 #endif
806                 if (stat(shallow, &st)) {
807                         if (mtime.sec)
808                                 die("shallow file was removed during fetch");
809                 } else if (st.st_mtime != mtime.sec
810 #ifdef USE_NSEC
811                                 || st.st_mtim.usec != mtime.usec
812 #endif
813                           )
814                         die("shallow file was changed during fetch");
816                 fd = hold_lock_file_for_update(&lock, shallow, 1);
817                 if (!write_shallow_commits(fd, 0)) {
818                         unlink(shallow);
819                         rollback_lock_file(&lock);
820                 } else {
821                         commit_lock_file(&lock);
822                 }
823         }
825         reprepare_packed_git();
826         return ref_cpy;