Merge branch 'at/rebase-fork-point-regression-fix'
[git] / remote.c
1 #include "cache.h"
2 #include "config.h"
3 #include "remote.h"
4 #include "refs.h"
5 #include "refspec.h"
6 #include "object-store.h"
7 #include "commit.h"
8 #include "diff.h"
9 #include "revision.h"
10 #include "dir.h"
11 #include "tag.h"
12 #include "string-list.h"
13 #include "mergesort.h"
14 #include "argv-array.h"
15 #include "commit-reach.h"
16 #include "advice.h"
17
18 enum map_direction { FROM_SRC, FROM_DST };
19
20 struct counted_string {
21         size_t len;
22         const char *s;
23 };
24 struct rewrite {
25         const char *base;
26         size_t baselen;
27         struct counted_string *instead_of;
28         int instead_of_nr;
29         int instead_of_alloc;
30 };
31 struct rewrites {
32         struct rewrite **rewrite;
33         int rewrite_alloc;
34         int rewrite_nr;
35 };
36
37 static struct remote **remotes;
38 static int remotes_alloc;
39 static int remotes_nr;
40 static struct hashmap remotes_hash;
41
42 static struct branch **branches;
43 static int branches_alloc;
44 static int branches_nr;
45
46 static struct branch *current_branch;
47 static const char *pushremote_name;
48
49 static struct rewrites rewrites;
50 static struct rewrites rewrites_push;
51
52 static int valid_remote(const struct remote *remote)
53 {
54         return (!!remote->url) || (!!remote->foreign_vcs);
55 }
56
57 static const char *alias_url(const char *url, struct rewrites *r)
58 {
59         int i, j;
60         struct counted_string *longest;
61         int longest_i;
62
63         longest = NULL;
64         longest_i = -1;
65         for (i = 0; i < r->rewrite_nr; i++) {
66                 if (!r->rewrite[i])
67                         continue;
68                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
69                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
70                             (!longest ||
71                              longest->len < r->rewrite[i]->instead_of[j].len)) {
72                                 longest = &(r->rewrite[i]->instead_of[j]);
73                                 longest_i = i;
74                         }
75                 }
76         }
77         if (!longest)
78                 return url;
79
80         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
81 }
82
83 static void add_url(struct remote *remote, const char *url)
84 {
85         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
86         remote->url[remote->url_nr++] = url;
87 }
88
89 static void add_pushurl(struct remote *remote, const char *pushurl)
90 {
91         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
92         remote->pushurl[remote->pushurl_nr++] = pushurl;
93 }
94
95 static void add_pushurl_alias(struct remote *remote, const char *url)
96 {
97         const char *pushurl = alias_url(url, &rewrites_push);
98         if (pushurl != url)
99                 add_pushurl(remote, pushurl);
100 }
101
102 static void add_url_alias(struct remote *remote, const char *url)
103 {
104         add_url(remote, alias_url(url, &rewrites));
105         add_pushurl_alias(remote, url);
106 }
107
108 struct remotes_hash_key {
109         const char *str;
110         int len;
111 };
112
113 static int remotes_hash_cmp(const void *unused_cmp_data,
114                             const struct hashmap_entry *eptr,
115                             const struct hashmap_entry *entry_or_key,
116                             const void *keydata)
117 {
118         const struct remote *a, *b;
119         const struct remotes_hash_key *key = keydata;
120
121         a = container_of(eptr, const struct remote, ent);
122         b = container_of(entry_or_key, const struct remote, ent);
123
124         if (key)
125                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
126         else
127                 return strcmp(a->name, b->name);
128 }
129
130 static inline void init_remotes_hash(void)
131 {
132         if (!remotes_hash.cmpfn)
133                 hashmap_init(&remotes_hash, remotes_hash_cmp, NULL, 0);
134 }
135
136 static struct remote *make_remote(const char *name, int len)
137 {
138         struct remote *ret, *replaced;
139         struct remotes_hash_key lookup;
140         struct hashmap_entry lookup_entry, *e;
141
142         if (!len)
143                 len = strlen(name);
144
145         init_remotes_hash();
146         lookup.str = name;
147         lookup.len = len;
148         hashmap_entry_init(&lookup_entry, memhash(name, len));
149
150         e = hashmap_get(&remotes_hash, &lookup_entry, &lookup);
151         if (e)
152                 return container_of(e, struct remote, ent);
153
154         ret = xcalloc(1, sizeof(struct remote));
155         ret->prune = -1;  /* unspecified */
156         ret->prune_tags = -1;  /* unspecified */
157         ret->name = xstrndup(name, len);
158         refspec_init(&ret->push, REFSPEC_PUSH);
159         refspec_init(&ret->fetch, REFSPEC_FETCH);
160
161         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
162         remotes[remotes_nr++] = ret;
163
164         hashmap_entry_init(&ret->ent, lookup_entry.hash);
165         replaced = hashmap_put_entry(&remotes_hash, ret, ent);
166         assert(replaced == NULL);  /* no previous entry overwritten */
167         return ret;
168 }
169
170 static void add_merge(struct branch *branch, const char *name)
171 {
172         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
173                    branch->merge_alloc);
174         branch->merge_name[branch->merge_nr++] = name;
175 }
176
177 static struct branch *make_branch(const char *name, int len)
178 {
179         struct branch *ret;
180         int i;
181
182         for (i = 0; i < branches_nr; i++) {
183                 if (len ? (!strncmp(name, branches[i]->name, len) &&
184                            !branches[i]->name[len]) :
185                     !strcmp(name, branches[i]->name))
186                         return branches[i];
187         }
188
189         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
190         ret = xcalloc(1, sizeof(struct branch));
191         branches[branches_nr++] = ret;
192         if (len)
193                 ret->name = xstrndup(name, len);
194         else
195                 ret->name = xstrdup(name);
196         ret->refname = xstrfmt("refs/heads/%s", ret->name);
197
198         return ret;
199 }
200
201 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
202 {
203         struct rewrite *ret;
204         int i;
205
206         for (i = 0; i < r->rewrite_nr; i++) {
207                 if (len
208                     ? (len == r->rewrite[i]->baselen &&
209                        !strncmp(base, r->rewrite[i]->base, len))
210                     : !strcmp(base, r->rewrite[i]->base))
211                         return r->rewrite[i];
212         }
213
214         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
215         ret = xcalloc(1, sizeof(struct rewrite));
216         r->rewrite[r->rewrite_nr++] = ret;
217         if (len) {
218                 ret->base = xstrndup(base, len);
219                 ret->baselen = len;
220         }
221         else {
222                 ret->base = xstrdup(base);
223                 ret->baselen = strlen(base);
224         }
225         return ret;
226 }
227
228 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
229 {
230         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
231         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
232         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
233         rewrite->instead_of_nr++;
234 }
235
236 static const char *skip_spaces(const char *s)
237 {
238         while (isspace(*s))
239                 s++;
240         return s;
241 }
242
243 static void read_remotes_file(struct remote *remote)
244 {
245         struct strbuf buf = STRBUF_INIT;
246         FILE *f = fopen_or_warn(git_path("remotes/%s", remote->name), "r");
247
248         if (!f)
249                 return;
250         remote->configured_in_repo = 1;
251         remote->origin = REMOTE_REMOTES;
252         while (strbuf_getline(&buf, f) != EOF) {
253                 const char *v;
254
255                 strbuf_rtrim(&buf);
256
257                 if (skip_prefix(buf.buf, "URL:", &v))
258                         add_url_alias(remote, xstrdup(skip_spaces(v)));
259                 else if (skip_prefix(buf.buf, "Push:", &v))
260                         refspec_append(&remote->push, skip_spaces(v));
261                 else if (skip_prefix(buf.buf, "Pull:", &v))
262                         refspec_append(&remote->fetch, skip_spaces(v));
263         }
264         strbuf_release(&buf);
265         fclose(f);
266 }
267
268 static void read_branches_file(struct remote *remote)
269 {
270         char *frag;
271         struct strbuf buf = STRBUF_INIT;
272         FILE *f = fopen_or_warn(git_path("branches/%s", remote->name), "r");
273
274         if (!f)
275                 return;
276
277         strbuf_getline_lf(&buf, f);
278         fclose(f);
279         strbuf_trim(&buf);
280         if (!buf.len) {
281                 strbuf_release(&buf);
282                 return;
283         }
284
285         remote->configured_in_repo = 1;
286         remote->origin = REMOTE_BRANCHES;
287
288         /*
289          * The branches file would have URL and optionally
290          * #branch specified.  The "master" (or specified) branch is
291          * fetched and stored in the local branch matching the
292          * remote name.
293          */
294         frag = strchr(buf.buf, '#');
295         if (frag)
296                 *(frag++) = '\0';
297         else
298                 frag = "master";
299
300         add_url_alias(remote, strbuf_detach(&buf, NULL));
301         strbuf_addf(&buf, "refs/heads/%s:refs/heads/%s",
302                     frag, remote->name);
303         refspec_append(&remote->fetch, buf.buf);
304
305         /*
306          * Cogito compatible push: push current HEAD to remote #branch
307          * (master if missing)
308          */
309         strbuf_reset(&buf);
310         strbuf_addf(&buf, "HEAD:refs/heads/%s", frag);
311         refspec_append(&remote->push, buf.buf);
312         remote->fetch_tags = 1; /* always auto-follow */
313         strbuf_release(&buf);
314 }
315
316 static int handle_config(const char *key, const char *value, void *cb)
317 {
318         const char *name;
319         int namelen;
320         const char *subkey;
321         struct remote *remote;
322         struct branch *branch;
323         if (parse_config_key(key, "branch", &name, &namelen, &subkey) >= 0) {
324                 if (!name)
325                         return 0;
326                 branch = make_branch(name, namelen);
327                 if (!strcmp(subkey, "remote")) {
328                         return git_config_string(&branch->remote_name, key, value);
329                 } else if (!strcmp(subkey, "pushremote")) {
330                         return git_config_string(&branch->pushremote_name, key, value);
331                 } else if (!strcmp(subkey, "merge")) {
332                         if (!value)
333                                 return config_error_nonbool(key);
334                         add_merge(branch, xstrdup(value));
335                 }
336                 return 0;
337         }
338         if (parse_config_key(key, "url", &name, &namelen, &subkey) >= 0) {
339                 struct rewrite *rewrite;
340                 if (!name)
341                         return 0;
342                 if (!strcmp(subkey, "insteadof")) {
343                         if (!value)
344                                 return config_error_nonbool(key);
345                         rewrite = make_rewrite(&rewrites, name, namelen);
346                         add_instead_of(rewrite, xstrdup(value));
347                 } else if (!strcmp(subkey, "pushinsteadof")) {
348                         if (!value)
349                                 return config_error_nonbool(key);
350                         rewrite = make_rewrite(&rewrites_push, name, namelen);
351                         add_instead_of(rewrite, xstrdup(value));
352                 }
353         }
354
355         if (parse_config_key(key, "remote", &name, &namelen, &subkey) < 0)
356                 return 0;
357
358         /* Handle remote.* variables */
359         if (!name && !strcmp(subkey, "pushdefault"))
360                 return git_config_string(&pushremote_name, key, value);
361
362         if (!name)
363                 return 0;
364         /* Handle remote.<name>.* variables */
365         if (*name == '/') {
366                 warning(_("config remote shorthand cannot begin with '/': %s"),
367                         name);
368                 return 0;
369         }
370         remote = make_remote(name, namelen);
371         remote->origin = REMOTE_CONFIG;
372         if (current_config_scope() == CONFIG_SCOPE_LOCAL ||
373         current_config_scope() == CONFIG_SCOPE_WORKTREE)
374                 remote->configured_in_repo = 1;
375         if (!strcmp(subkey, "mirror"))
376                 remote->mirror = git_config_bool(key, value);
377         else if (!strcmp(subkey, "skipdefaultupdate"))
378                 remote->skip_default_update = git_config_bool(key, value);
379         else if (!strcmp(subkey, "skipfetchall"))
380                 remote->skip_default_update = git_config_bool(key, value);
381         else if (!strcmp(subkey, "prune"))
382                 remote->prune = git_config_bool(key, value);
383         else if (!strcmp(subkey, "prunetags"))
384                 remote->prune_tags = git_config_bool(key, value);
385         else if (!strcmp(subkey, "url")) {
386                 const char *v;
387                 if (git_config_string(&v, key, value))
388                         return -1;
389                 add_url(remote, v);
390         } else if (!strcmp(subkey, "pushurl")) {
391                 const char *v;
392                 if (git_config_string(&v, key, value))
393                         return -1;
394                 add_pushurl(remote, v);
395         } else if (!strcmp(subkey, "push")) {
396                 const char *v;
397                 if (git_config_string(&v, key, value))
398                         return -1;
399                 refspec_append(&remote->push, v);
400                 free((char *)v);
401         } else if (!strcmp(subkey, "fetch")) {
402                 const char *v;
403                 if (git_config_string(&v, key, value))
404                         return -1;
405                 refspec_append(&remote->fetch, v);
406                 free((char *)v);
407         } else if (!strcmp(subkey, "receivepack")) {
408                 const char *v;
409                 if (git_config_string(&v, key, value))
410                         return -1;
411                 if (!remote->receivepack)
412                         remote->receivepack = v;
413                 else
414                         error(_("more than one receivepack given, using the first"));
415         } else if (!strcmp(subkey, "uploadpack")) {
416                 const char *v;
417                 if (git_config_string(&v, key, value))
418                         return -1;
419                 if (!remote->uploadpack)
420                         remote->uploadpack = v;
421                 else
422                         error(_("more than one uploadpack given, using the first"));
423         } else if (!strcmp(subkey, "tagopt")) {
424                 if (!strcmp(value, "--no-tags"))
425                         remote->fetch_tags = -1;
426                 else if (!strcmp(value, "--tags"))
427                         remote->fetch_tags = 2;
428         } else if (!strcmp(subkey, "proxy")) {
429                 return git_config_string((const char **)&remote->http_proxy,
430                                          key, value);
431         } else if (!strcmp(subkey, "proxyauthmethod")) {
432                 return git_config_string((const char **)&remote->http_proxy_authmethod,
433                                          key, value);
434         } else if (!strcmp(subkey, "vcs")) {
435                 return git_config_string(&remote->foreign_vcs, key, value);
436         }
437         return 0;
438 }
439
440 static void alias_all_urls(void)
441 {
442         int i, j;
443         for (i = 0; i < remotes_nr; i++) {
444                 int add_pushurl_aliases;
445                 if (!remotes[i])
446                         continue;
447                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
448                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
449                 }
450                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
451                 for (j = 0; j < remotes[i]->url_nr; j++) {
452                         if (add_pushurl_aliases)
453                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
454                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
455                 }
456         }
457 }
458
459 static void read_config(void)
460 {
461         static int loaded;
462         int flag;
463
464         if (loaded)
465                 return;
466         loaded = 1;
467
468         current_branch = NULL;
469         if (startup_info->have_repository) {
470                 const char *head_ref = resolve_ref_unsafe("HEAD", 0, NULL, &flag);
471                 if (head_ref && (flag & REF_ISSYMREF) &&
472                     skip_prefix(head_ref, "refs/heads/", &head_ref)) {
473                         current_branch = make_branch(head_ref, 0);
474                 }
475         }
476         git_config(handle_config, NULL);
477         alias_all_urls();
478 }
479
480 static int valid_remote_nick(const char *name)
481 {
482         if (!name[0] || is_dot_or_dotdot(name))
483                 return 0;
484
485         /* remote nicknames cannot contain slashes */
486         while (*name)
487                 if (is_dir_sep(*name++))
488                         return 0;
489         return 1;
490 }
491
492 const char *remote_for_branch(struct branch *branch, int *explicit)
493 {
494         if (branch && branch->remote_name) {
495                 if (explicit)
496                         *explicit = 1;
497                 return branch->remote_name;
498         }
499         if (explicit)
500                 *explicit = 0;
501         return "origin";
502 }
503
504 const char *pushremote_for_branch(struct branch *branch, int *explicit)
505 {
506         if (branch && branch->pushremote_name) {
507                 if (explicit)
508                         *explicit = 1;
509                 return branch->pushremote_name;
510         }
511         if (pushremote_name) {
512                 if (explicit)
513                         *explicit = 1;
514                 return pushremote_name;
515         }
516         return remote_for_branch(branch, explicit);
517 }
518
519 const char *remote_ref_for_branch(struct branch *branch, int for_push)
520 {
521         if (branch) {
522                 if (!for_push) {
523                         if (branch->merge_nr) {
524                                 return branch->merge_name[0];
525                         }
526                 } else {
527                         const char *dst, *remote_name =
528                                 pushremote_for_branch(branch, NULL);
529                         struct remote *remote = remote_get(remote_name);
530
531                         if (remote && remote->push.nr &&
532                             (dst = apply_refspecs(&remote->push,
533                                                   branch->refname))) {
534                                 return dst;
535                         }
536                 }
537         }
538         return NULL;
539 }
540
541 static struct remote *remote_get_1(const char *name,
542                                    const char *(*get_default)(struct branch *, int *))
543 {
544         struct remote *ret;
545         int name_given = 0;
546
547         read_config();
548
549         if (name)
550                 name_given = 1;
551         else
552                 name = get_default(current_branch, &name_given);
553
554         ret = make_remote(name, 0);
555         if (valid_remote_nick(name) && have_git_dir()) {
556                 if (!valid_remote(ret))
557                         read_remotes_file(ret);
558                 if (!valid_remote(ret))
559                         read_branches_file(ret);
560         }
561         if (name_given && !valid_remote(ret))
562                 add_url_alias(ret, name);
563         if (!valid_remote(ret))
564                 return NULL;
565         return ret;
566 }
567
568 struct remote *remote_get(const char *name)
569 {
570         return remote_get_1(name, remote_for_branch);
571 }
572
573 struct remote *pushremote_get(const char *name)
574 {
575         return remote_get_1(name, pushremote_for_branch);
576 }
577
578 int remote_is_configured(struct remote *remote, int in_repo)
579 {
580         if (!remote)
581                 return 0;
582         if (in_repo)
583                 return remote->configured_in_repo;
584         return !!remote->origin;
585 }
586
587 int for_each_remote(each_remote_fn fn, void *priv)
588 {
589         int i, result = 0;
590         read_config();
591         for (i = 0; i < remotes_nr && !result; i++) {
592                 struct remote *r = remotes[i];
593                 if (!r)
594                         continue;
595                 result = fn(r, priv);
596         }
597         return result;
598 }
599
600 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
601 {
602         if (strcmp(ref1->name, ref2->name)) {
603                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
604                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
605                         die(_("Cannot fetch both %s and %s to %s"),
606                             ref1->name, ref2->name, ref2->peer_ref->name);
607                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
608                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
609                         warning(_("%s usually tracks %s, not %s"),
610                                 ref2->peer_ref->name, ref2->name, ref1->name);
611                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
612                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
613                         die(_("%s tracks both %s and %s"),
614                             ref2->peer_ref->name, ref1->name, ref2->name);
615                 } else {
616                         /*
617                          * This last possibility doesn't occur because
618                          * FETCH_HEAD_IGNORE entries always appear at
619                          * the end of the list.
620                          */
621                         BUG("Internal error");
622                 }
623         }
624         free(ref2->peer_ref);
625         free(ref2);
626 }
627
628 struct ref *ref_remove_duplicates(struct ref *ref_map)
629 {
630         struct string_list refs = STRING_LIST_INIT_NODUP;
631         struct ref *retval = NULL;
632         struct ref **p = &retval;
633
634         while (ref_map) {
635                 struct ref *ref = ref_map;
636
637                 ref_map = ref_map->next;
638                 ref->next = NULL;
639
640                 if (!ref->peer_ref) {
641                         *p = ref;
642                         p = &ref->next;
643                 } else {
644                         struct string_list_item *item =
645                                 string_list_insert(&refs, ref->peer_ref->name);
646
647                         if (item->util) {
648                                 /* Entry already existed */
649                                 handle_duplicate((struct ref *)item->util, ref);
650                         } else {
651                                 *p = ref;
652                                 p = &ref->next;
653                                 item->util = ref;
654                         }
655                 }
656         }
657
658         string_list_clear(&refs, 0);
659         return retval;
660 }
661
662 int remote_has_url(struct remote *remote, const char *url)
663 {
664         int i;
665         for (i = 0; i < remote->url_nr; i++) {
666                 if (!strcmp(remote->url[i], url))
667                         return 1;
668         }
669         return 0;
670 }
671
672 static int match_name_with_pattern(const char *key, const char *name,
673                                    const char *value, char **result)
674 {
675         const char *kstar = strchr(key, '*');
676         size_t klen;
677         size_t ksuffixlen;
678         size_t namelen;
679         int ret;
680         if (!kstar)
681                 die(_("key '%s' of pattern had no '*'"), key);
682         klen = kstar - key;
683         ksuffixlen = strlen(kstar + 1);
684         namelen = strlen(name);
685         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
686                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
687         if (ret && value) {
688                 struct strbuf sb = STRBUF_INIT;
689                 const char *vstar = strchr(value, '*');
690                 if (!vstar)
691                         die(_("value '%s' of pattern has no '*'"), value);
692                 strbuf_add(&sb, value, vstar - value);
693                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
694                 strbuf_addstr(&sb, vstar + 1);
695                 *result = strbuf_detach(&sb, NULL);
696         }
697         return ret;
698 }
699
700 static void query_refspecs_multiple(struct refspec *rs,
701                                     struct refspec_item *query,
702                                     struct string_list *results)
703 {
704         int i;
705         int find_src = !query->src;
706
707         if (find_src && !query->dst)
708                 BUG("query_refspecs_multiple: need either src or dst");
709
710         for (i = 0; i < rs->nr; i++) {
711                 struct refspec_item *refspec = &rs->items[i];
712                 const char *key = find_src ? refspec->dst : refspec->src;
713                 const char *value = find_src ? refspec->src : refspec->dst;
714                 const char *needle = find_src ? query->dst : query->src;
715                 char **result = find_src ? &query->src : &query->dst;
716
717                 if (!refspec->dst)
718                         continue;
719                 if (refspec->pattern) {
720                         if (match_name_with_pattern(key, needle, value, result))
721                                 string_list_append_nodup(results, *result);
722                 } else if (!strcmp(needle, key)) {
723                         string_list_append(results, value);
724                 }
725         }
726 }
727
728 int query_refspecs(struct refspec *rs, struct refspec_item *query)
729 {
730         int i;
731         int find_src = !query->src;
732         const char *needle = find_src ? query->dst : query->src;
733         char **result = find_src ? &query->src : &query->dst;
734
735         if (find_src && !query->dst)
736                 BUG("query_refspecs: need either src or dst");
737
738         for (i = 0; i < rs->nr; i++) {
739                 struct refspec_item *refspec = &rs->items[i];
740                 const char *key = find_src ? refspec->dst : refspec->src;
741                 const char *value = find_src ? refspec->src : refspec->dst;
742
743                 if (!refspec->dst)
744                         continue;
745                 if (refspec->pattern) {
746                         if (match_name_with_pattern(key, needle, value, result)) {
747                                 query->force = refspec->force;
748                                 return 0;
749                         }
750                 } else if (!strcmp(needle, key)) {
751                         *result = xstrdup(value);
752                         query->force = refspec->force;
753                         return 0;
754                 }
755         }
756         return -1;
757 }
758
759 char *apply_refspecs(struct refspec *rs, const char *name)
760 {
761         struct refspec_item query;
762
763         memset(&query, 0, sizeof(struct refspec_item));
764         query.src = (char *)name;
765
766         if (query_refspecs(rs, &query))
767                 return NULL;
768
769         return query.dst;
770 }
771
772 int remote_find_tracking(struct remote *remote, struct refspec_item *refspec)
773 {
774         return query_refspecs(&remote->fetch, refspec);
775 }
776
777 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
778                 const char *name)
779 {
780         size_t len = strlen(name);
781         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
782         memcpy(ref->name, prefix, prefixlen);
783         memcpy(ref->name + prefixlen, name, len);
784         return ref;
785 }
786
787 struct ref *alloc_ref(const char *name)
788 {
789         return alloc_ref_with_prefix("", 0, name);
790 }
791
792 struct ref *copy_ref(const struct ref *ref)
793 {
794         struct ref *cpy;
795         size_t len;
796         if (!ref)
797                 return NULL;
798         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
799         cpy = xmalloc(len);
800         memcpy(cpy, ref, len);
801         cpy->next = NULL;
802         cpy->symref = xstrdup_or_null(ref->symref);
803         cpy->remote_status = xstrdup_or_null(ref->remote_status);
804         cpy->peer_ref = copy_ref(ref->peer_ref);
805         return cpy;
806 }
807
808 struct ref *copy_ref_list(const struct ref *ref)
809 {
810         struct ref *ret = NULL;
811         struct ref **tail = &ret;
812         while (ref) {
813                 *tail = copy_ref(ref);
814                 ref = ref->next;
815                 tail = &((*tail)->next);
816         }
817         return ret;
818 }
819
820 void free_one_ref(struct ref *ref)
821 {
822         if (!ref)
823                 return;
824         free_one_ref(ref->peer_ref);
825         free(ref->remote_status);
826         free(ref->symref);
827         free(ref);
828 }
829
830 void free_refs(struct ref *ref)
831 {
832         struct ref *next;
833         while (ref) {
834                 next = ref->next;
835                 free_one_ref(ref);
836                 ref = next;
837         }
838 }
839
840 int ref_compare_name(const void *va, const void *vb)
841 {
842         const struct ref *a = va, *b = vb;
843         return strcmp(a->name, b->name);
844 }
845
846 static void *ref_list_get_next(const void *a)
847 {
848         return ((const struct ref *)a)->next;
849 }
850
851 static void ref_list_set_next(void *a, void *next)
852 {
853         ((struct ref *)a)->next = next;
854 }
855
856 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
857 {
858         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
859 }
860
861 int count_refspec_match(const char *pattern,
862                         struct ref *refs,
863                         struct ref **matched_ref)
864 {
865         int patlen = strlen(pattern);
866         struct ref *matched_weak = NULL;
867         struct ref *matched = NULL;
868         int weak_match = 0;
869         int match = 0;
870
871         for (weak_match = match = 0; refs; refs = refs->next) {
872                 char *name = refs->name;
873                 int namelen = strlen(name);
874
875                 if (!refname_match(pattern, name))
876                         continue;
877
878                 /* A match is "weak" if it is with refs outside
879                  * heads or tags, and did not specify the pattern
880                  * in full (e.g. "refs/remotes/origin/master") or at
881                  * least from the toplevel (e.g. "remotes/origin/master");
882                  * otherwise "git push $URL master" would result in
883                  * ambiguity between remotes/origin/master and heads/master
884                  * at the remote site.
885                  */
886                 if (namelen != patlen &&
887                     patlen != namelen - 5 &&
888                     !starts_with(name, "refs/heads/") &&
889                     !starts_with(name, "refs/tags/")) {
890                         /* We want to catch the case where only weak
891                          * matches are found and there are multiple
892                          * matches, and where more than one strong
893                          * matches are found, as ambiguous.  One
894                          * strong match with zero or more weak matches
895                          * are acceptable as a unique match.
896                          */
897                         matched_weak = refs;
898                         weak_match++;
899                 }
900                 else {
901                         matched = refs;
902                         match++;
903                 }
904         }
905         if (!matched) {
906                 if (matched_ref)
907                         *matched_ref = matched_weak;
908                 return weak_match;
909         }
910         else {
911                 if (matched_ref)
912                         *matched_ref = matched;
913                 return match;
914         }
915 }
916
917 static void tail_link_ref(struct ref *ref, struct ref ***tail)
918 {
919         **tail = ref;
920         while (ref->next)
921                 ref = ref->next;
922         *tail = &ref->next;
923 }
924
925 static struct ref *alloc_delete_ref(void)
926 {
927         struct ref *ref = alloc_ref("(delete)");
928         oidclr(&ref->new_oid);
929         return ref;
930 }
931
932 static int try_explicit_object_name(const char *name,
933                                     struct ref **match)
934 {
935         struct object_id oid;
936
937         if (!*name) {
938                 if (match)
939                         *match = alloc_delete_ref();
940                 return 0;
941         }
942
943         if (get_oid(name, &oid))
944                 return -1;
945
946         if (match) {
947                 *match = alloc_ref(name);
948                 oidcpy(&(*match)->new_oid, &oid);
949         }
950         return 0;
951 }
952
953 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
954 {
955         struct ref *ret = alloc_ref(name);
956         tail_link_ref(ret, tail);
957         return ret;
958 }
959
960 static char *guess_ref(const char *name, struct ref *peer)
961 {
962         struct strbuf buf = STRBUF_INIT;
963
964         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
965                                            NULL, NULL);
966         if (!r)
967                 return NULL;
968
969         if (starts_with(r, "refs/heads/")) {
970                 strbuf_addstr(&buf, "refs/heads/");
971         } else if (starts_with(r, "refs/tags/")) {
972                 strbuf_addstr(&buf, "refs/tags/");
973         } else {
974                 return NULL;
975         }
976
977         strbuf_addstr(&buf, name);
978         return strbuf_detach(&buf, NULL);
979 }
980
981 static int match_explicit_lhs(struct ref *src,
982                               struct refspec_item *rs,
983                               struct ref **match,
984                               int *allocated_match)
985 {
986         switch (count_refspec_match(rs->src, src, match)) {
987         case 1:
988                 if (allocated_match)
989                         *allocated_match = 0;
990                 return 0;
991         case 0:
992                 /* The source could be in the get_sha1() format
993                  * not a reference name.  :refs/other is a
994                  * way to delete 'other' ref at the remote end.
995                  */
996                 if (try_explicit_object_name(rs->src, match) < 0)
997                         return error(_("src refspec %s does not match any"), rs->src);
998                 if (allocated_match)
999                         *allocated_match = 1;
1000                 return 0;
1001         default:
1002                 return error(_("src refspec %s matches more than one"), rs->src);
1003         }
1004 }
1005
1006 static void show_push_unqualified_ref_name_error(const char *dst_value,
1007                                                  const char *matched_src_name)
1008 {
1009         struct object_id oid;
1010         enum object_type type;
1011
1012         /*
1013          * TRANSLATORS: "matches '%s'%" is the <dst> part of "git push
1014          * <remote> <src>:<dst>" push, and "being pushed ('%s')" is
1015          * the <src>.
1016          */
1017         error(_("The destination you provided is not a full refname (i.e.,\n"
1018                 "starting with \"refs/\"). We tried to guess what you meant by:\n"
1019                 "\n"
1020                 "- Looking for a ref that matches '%s' on the remote side.\n"
1021                 "- Checking if the <src> being pushed ('%s')\n"
1022                 "  is a ref in \"refs/{heads,tags}/\". If so we add a corresponding\n"
1023                 "  refs/{heads,tags}/ prefix on the remote side.\n"
1024                 "\n"
1025                 "Neither worked, so we gave up. You must fully qualify the ref."),
1026               dst_value, matched_src_name);
1027
1028         if (!advice_push_unqualified_ref_name)
1029                 return;
1030
1031         if (get_oid(matched_src_name, &oid))
1032                 BUG("'%s' is not a valid object, "
1033                     "match_explicit_lhs() should catch this!",
1034                     matched_src_name);
1035         type = oid_object_info(the_repository, &oid, NULL);
1036         if (type == OBJ_COMMIT) {
1037                 advise(_("The <src> part of the refspec is a commit object.\n"
1038                          "Did you mean to create a new branch by pushing to\n"
1039                          "'%s:refs/heads/%s'?"),
1040                        matched_src_name, dst_value);
1041         } else if (type == OBJ_TAG) {
1042                 advise(_("The <src> part of the refspec is a tag object.\n"
1043                          "Did you mean to create a new tag by pushing to\n"
1044                          "'%s:refs/tags/%s'?"),
1045                        matched_src_name, dst_value);
1046         } else if (type == OBJ_TREE) {
1047                 advise(_("The <src> part of the refspec is a tree object.\n"
1048                          "Did you mean to tag a new tree by pushing to\n"
1049                          "'%s:refs/tags/%s'?"),
1050                        matched_src_name, dst_value);
1051         } else if (type == OBJ_BLOB) {
1052                 advise(_("The <src> part of the refspec is a blob object.\n"
1053                          "Did you mean to tag a new blob by pushing to\n"
1054                          "'%s:refs/tags/%s'?"),
1055                        matched_src_name, dst_value);
1056         } else {
1057                 BUG("'%s' should be commit/tag/tree/blob, is '%d'",
1058                     matched_src_name, type);
1059         }
1060 }
1061
1062 static int match_explicit(struct ref *src, struct ref *dst,
1063                           struct ref ***dst_tail,
1064                           struct refspec_item *rs)
1065 {
1066         struct ref *matched_src, *matched_dst;
1067         int allocated_src;
1068
1069         const char *dst_value = rs->dst;
1070         char *dst_guess;
1071
1072         if (rs->pattern || rs->matching)
1073                 return 0;
1074
1075         matched_src = matched_dst = NULL;
1076         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1077                 return -1;
1078
1079         if (!dst_value) {
1080                 int flag;
1081
1082                 dst_value = resolve_ref_unsafe(matched_src->name,
1083                                                RESOLVE_REF_READING,
1084                                                NULL, &flag);
1085                 if (!dst_value ||
1086                     ((flag & REF_ISSYMREF) &&
1087                      !starts_with(dst_value, "refs/heads/")))
1088                         die(_("%s cannot be resolved to branch"),
1089                             matched_src->name);
1090         }
1091
1092         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1093         case 1:
1094                 break;
1095         case 0:
1096                 if (starts_with(dst_value, "refs/")) {
1097                         matched_dst = make_linked_ref(dst_value, dst_tail);
1098                 } else if (is_null_oid(&matched_src->new_oid)) {
1099                         error(_("unable to delete '%s': remote ref does not exist"),
1100                               dst_value);
1101                 } else if ((dst_guess = guess_ref(dst_value, matched_src))) {
1102                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1103                         free(dst_guess);
1104                 } else {
1105                         show_push_unqualified_ref_name_error(dst_value,
1106                                                              matched_src->name);
1107                 }
1108                 break;
1109         default:
1110                 matched_dst = NULL;
1111                 error(_("dst refspec %s matches more than one"),
1112                       dst_value);
1113                 break;
1114         }
1115         if (!matched_dst)
1116                 return -1;
1117         if (matched_dst->peer_ref)
1118                 return error(_("dst ref %s receives from more than one src"),
1119                              matched_dst->name);
1120         else {
1121                 matched_dst->peer_ref = allocated_src ?
1122                                         matched_src :
1123                                         copy_ref(matched_src);
1124                 matched_dst->force = rs->force;
1125         }
1126         return 0;
1127 }
1128
1129 static int match_explicit_refs(struct ref *src, struct ref *dst,
1130                                struct ref ***dst_tail, struct refspec *rs)
1131 {
1132         int i, errs;
1133         for (i = errs = 0; i < rs->nr; i++)
1134                 errs += match_explicit(src, dst, dst_tail, &rs->items[i]);
1135         return errs;
1136 }
1137
1138 static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
1139                            int send_mirror, int direction,
1140                            const struct refspec_item **ret_pat)
1141 {
1142         const struct refspec_item *pat;
1143         char *name;
1144         int i;
1145         int matching_refs = -1;
1146         for (i = 0; i < rs->nr; i++) {
1147                 const struct refspec_item *item = &rs->items[i];
1148                 if (item->matching &&
1149                     (matching_refs == -1 || item->force)) {
1150                         matching_refs = i;
1151                         continue;
1152                 }
1153
1154                 if (item->pattern) {
1155                         const char *dst_side = item->dst ? item->dst : item->src;
1156                         int match;
1157                         if (direction == FROM_SRC)
1158                                 match = match_name_with_pattern(item->src, ref->name, dst_side, &name);
1159                         else
1160                                 match = match_name_with_pattern(dst_side, ref->name, item->src, &name);
1161                         if (match) {
1162                                 matching_refs = i;
1163                                 break;
1164                         }
1165                 }
1166         }
1167         if (matching_refs == -1)
1168                 return NULL;
1169
1170         pat = &rs->items[matching_refs];
1171         if (pat->matching) {
1172                 /*
1173                  * "matching refs"; traditionally we pushed everything
1174                  * including refs outside refs/heads/ hierarchy, but
1175                  * that does not make much sense these days.
1176                  */
1177                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1178                         return NULL;
1179                 name = xstrdup(ref->name);
1180         }
1181         if (ret_pat)
1182                 *ret_pat = pat;
1183         return name;
1184 }
1185
1186 static struct ref **tail_ref(struct ref **head)
1187 {
1188         struct ref **tail = head;
1189         while (*tail)
1190                 tail = &((*tail)->next);
1191         return tail;
1192 }
1193
1194 struct tips {
1195         struct commit **tip;
1196         int nr, alloc;
1197 };
1198
1199 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1200 {
1201         struct commit *commit;
1202
1203         if (is_null_oid(oid))
1204                 return;
1205         commit = lookup_commit_reference_gently(the_repository, oid, 1);
1206         if (!commit || (commit->object.flags & TMP_MARK))
1207                 return;
1208         commit->object.flags |= TMP_MARK;
1209         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1210         tips->tip[tips->nr++] = commit;
1211 }
1212
1213 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1214 {
1215         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1216         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1217         struct string_list_item *item;
1218         struct ref *ref;
1219         struct tips sent_tips;
1220
1221         /*
1222          * Collect everything we know they would have at the end of
1223          * this push, and collect all tags they have.
1224          */
1225         memset(&sent_tips, 0, sizeof(sent_tips));
1226         for (ref = *dst; ref; ref = ref->next) {
1227                 if (ref->peer_ref &&
1228                     !is_null_oid(&ref->peer_ref->new_oid))
1229                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1230                 else
1231                         add_to_tips(&sent_tips, &ref->old_oid);
1232                 if (starts_with(ref->name, "refs/tags/"))
1233                         string_list_append(&dst_tag, ref->name);
1234         }
1235         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1236
1237         string_list_sort(&dst_tag);
1238
1239         /* Collect tags they do not have. */
1240         for (ref = src; ref; ref = ref->next) {
1241                 if (!starts_with(ref->name, "refs/tags/"))
1242                         continue; /* not a tag */
1243                 if (string_list_has_string(&dst_tag, ref->name))
1244                         continue; /* they already have it */
1245                 if (oid_object_info(the_repository, &ref->new_oid, NULL) != OBJ_TAG)
1246                         continue; /* be conservative */
1247                 item = string_list_append(&src_tag, ref->name);
1248                 item->util = ref;
1249         }
1250         string_list_clear(&dst_tag, 0);
1251
1252         /*
1253          * At this point, src_tag lists tags that are missing from
1254          * dst, and sent_tips lists the tips we are pushing or those
1255          * that we know they already have. An element in the src_tag
1256          * that is an ancestor of any of the sent_tips needs to be
1257          * sent to the other side.
1258          */
1259         if (sent_tips.nr) {
1260                 const int reachable_flag = 1;
1261                 struct commit_list *found_commits;
1262                 struct commit **src_commits;
1263                 int nr_src_commits = 0, alloc_src_commits = 16;
1264                 ALLOC_ARRAY(src_commits, alloc_src_commits);
1265
1266                 for_each_string_list_item(item, &src_tag) {
1267                         struct ref *ref = item->util;
1268                         struct commit *commit;
1269
1270                         if (is_null_oid(&ref->new_oid))
1271                                 continue;
1272                         commit = lookup_commit_reference_gently(the_repository,
1273                                                                 &ref->new_oid,
1274                                                                 1);
1275                         if (!commit)
1276                                 /* not pushing a commit, which is not an error */
1277                                 continue;
1278
1279                         ALLOC_GROW(src_commits, nr_src_commits + 1, alloc_src_commits);
1280                         src_commits[nr_src_commits++] = commit;
1281                 }
1282
1283                 found_commits = get_reachable_subset(sent_tips.tip, sent_tips.nr,
1284                                                      src_commits, nr_src_commits,
1285                                                      reachable_flag);
1286
1287                 for_each_string_list_item(item, &src_tag) {
1288                         struct ref *dst_ref;
1289                         struct ref *ref = item->util;
1290                         struct commit *commit;
1291
1292                         if (is_null_oid(&ref->new_oid))
1293                                 continue;
1294                         commit = lookup_commit_reference_gently(the_repository,
1295                                                                 &ref->new_oid,
1296                                                                 1);
1297                         if (!commit)
1298                                 /* not pushing a commit, which is not an error */
1299                                 continue;
1300
1301                         /*
1302                          * Is this tag, which they do not have, reachable from
1303                          * any of the commits we are sending?
1304                          */
1305                         if (!(commit->object.flags & reachable_flag))
1306                                 continue;
1307
1308                         /* Add it in */
1309                         dst_ref = make_linked_ref(ref->name, dst_tail);
1310                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1311                         dst_ref->peer_ref = copy_ref(ref);
1312                 }
1313
1314                 clear_commit_marks_many(nr_src_commits, src_commits, reachable_flag);
1315                 free(src_commits);
1316                 free_commit_list(found_commits);
1317         }
1318
1319         string_list_clear(&src_tag, 0);
1320         free(sent_tips.tip);
1321 }
1322
1323 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1324 {
1325         for ( ; list; list = list->next)
1326                 if (!strcmp(list->name, name))
1327                         return (struct ref *)list;
1328         return NULL;
1329 }
1330
1331 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1332 {
1333         for ( ; ref; ref = ref->next)
1334                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1335
1336         string_list_sort(ref_index);
1337 }
1338
1339 /*
1340  * Given only the set of local refs, sanity-check the set of push
1341  * refspecs. We can't catch all errors that match_push_refs would,
1342  * but we can catch some errors early before even talking to the
1343  * remote side.
1344  */
1345 int check_push_refs(struct ref *src, struct refspec *rs)
1346 {
1347         int ret = 0;
1348         int i;
1349
1350         for (i = 0; i < rs->nr; i++) {
1351                 struct refspec_item *item = &rs->items[i];
1352
1353                 if (item->pattern || item->matching)
1354                         continue;
1355
1356                 ret |= match_explicit_lhs(src, item, NULL, NULL);
1357         }
1358
1359         return ret;
1360 }
1361
1362 /*
1363  * Given the set of refs the local repository has, the set of refs the
1364  * remote repository has, and the refspec used for push, determine
1365  * what remote refs we will update and with what value by setting
1366  * peer_ref (which object is being pushed) and force (if the push is
1367  * forced) in elements of "dst". The function may add new elements to
1368  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1369  */
1370 int match_push_refs(struct ref *src, struct ref **dst,
1371                     struct refspec *rs, int flags)
1372 {
1373         int send_all = flags & MATCH_REFS_ALL;
1374         int send_mirror = flags & MATCH_REFS_MIRROR;
1375         int send_prune = flags & MATCH_REFS_PRUNE;
1376         int errs;
1377         struct ref *ref, **dst_tail = tail_ref(dst);
1378         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1379
1380         /* If no refspec is provided, use the default ":" */
1381         if (!rs->nr)
1382                 refspec_append(rs, ":");
1383
1384         errs = match_explicit_refs(src, *dst, &dst_tail, rs);
1385
1386         /* pick the remainder */
1387         for (ref = src; ref; ref = ref->next) {
1388                 struct string_list_item *dst_item;
1389                 struct ref *dst_peer;
1390                 const struct refspec_item *pat = NULL;
1391                 char *dst_name;
1392
1393                 dst_name = get_ref_match(rs, ref, send_mirror, FROM_SRC, &pat);
1394                 if (!dst_name)
1395                         continue;
1396
1397                 if (!dst_ref_index.nr)
1398                         prepare_ref_index(&dst_ref_index, *dst);
1399
1400                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1401                 dst_peer = dst_item ? dst_item->util : NULL;
1402                 if (dst_peer) {
1403                         if (dst_peer->peer_ref)
1404                                 /* We're already sending something to this ref. */
1405                                 goto free_name;
1406                 } else {
1407                         if (pat->matching && !(send_all || send_mirror))
1408                                 /*
1409                                  * Remote doesn't have it, and we have no
1410                                  * explicit pattern, and we don't have
1411                                  * --all or --mirror.
1412                                  */
1413                                 goto free_name;
1414
1415                         /* Create a new one and link it */
1416                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1417                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1418                         string_list_insert(&dst_ref_index,
1419                                 dst_peer->name)->util = dst_peer;
1420                 }
1421                 dst_peer->peer_ref = copy_ref(ref);
1422                 dst_peer->force = pat->force;
1423         free_name:
1424                 free(dst_name);
1425         }
1426
1427         string_list_clear(&dst_ref_index, 0);
1428
1429         if (flags & MATCH_REFS_FOLLOW_TAGS)
1430                 add_missing_tags(src, dst, &dst_tail);
1431
1432         if (send_prune) {
1433                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1434                 /* check for missing refs on the remote */
1435                 for (ref = *dst; ref; ref = ref->next) {
1436                         char *src_name;
1437
1438                         if (ref->peer_ref)
1439                                 /* We're already sending something to this ref. */
1440                                 continue;
1441
1442                         src_name = get_ref_match(rs, ref, send_mirror, FROM_DST, NULL);
1443                         if (src_name) {
1444                                 if (!src_ref_index.nr)
1445                                         prepare_ref_index(&src_ref_index, src);
1446                                 if (!string_list_has_string(&src_ref_index,
1447                                             src_name))
1448                                         ref->peer_ref = alloc_delete_ref();
1449                                 free(src_name);
1450                         }
1451                 }
1452                 string_list_clear(&src_ref_index, 0);
1453         }
1454
1455         if (errs)
1456                 return -1;
1457         return 0;
1458 }
1459
1460 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1461                              int force_update)
1462 {
1463         struct ref *ref;
1464
1465         for (ref = remote_refs; ref; ref = ref->next) {
1466                 int force_ref_update = ref->force || force_update;
1467                 int reject_reason = 0;
1468
1469                 if (ref->peer_ref)
1470                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1471                 else if (!send_mirror)
1472                         continue;
1473
1474                 ref->deletion = is_null_oid(&ref->new_oid);
1475                 if (!ref->deletion &&
1476                         oideq(&ref->old_oid, &ref->new_oid)) {
1477                         ref->status = REF_STATUS_UPTODATE;
1478                         continue;
1479                 }
1480
1481                 /*
1482                  * If the remote ref has moved and is now different
1483                  * from what we expect, reject any push.
1484                  *
1485                  * It also is an error if the user told us to check
1486                  * with the remote-tracking branch to find the value
1487                  * to expect, but we did not have such a tracking
1488                  * branch.
1489                  */
1490                 if (ref->expect_old_sha1) {
1491                         if (!oideq(&ref->old_oid, &ref->old_oid_expect))
1492                                 reject_reason = REF_STATUS_REJECT_STALE;
1493                         else
1494                                 /* If the ref isn't stale then force the update. */
1495                                 force_ref_update = 1;
1496                 }
1497
1498                 /*
1499                  * If the update isn't already rejected then check
1500                  * the usual "must fast-forward" rules.
1501                  *
1502                  * Decide whether an individual refspec A:B can be
1503                  * pushed.  The push will succeed if any of the
1504                  * following are true:
1505                  *
1506                  * (1) the remote reference B does not exist
1507                  *
1508                  * (2) the remote reference B is being removed (i.e.,
1509                  *     pushing :B where no source is specified)
1510                  *
1511                  * (3) the destination is not under refs/tags/, and
1512                  *     if the old and new value is a commit, the new
1513                  *     is a descendant of the old.
1514                  *
1515                  * (4) it is forced using the +A:B notation, or by
1516                  *     passing the --force argument
1517                  */
1518
1519                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1520                         if (starts_with(ref->name, "refs/tags/"))
1521                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1522                         else if (!has_object_file(&ref->old_oid))
1523                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1524                         else if (!lookup_commit_reference_gently(the_repository, &ref->old_oid, 1) ||
1525                                  !lookup_commit_reference_gently(the_repository, &ref->new_oid, 1))
1526                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1527                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1528                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1529                 }
1530
1531                 /*
1532                  * "--force" will defeat any rejection implemented
1533                  * by the rules above.
1534                  */
1535                 if (!force_ref_update)
1536                         ref->status = reject_reason;
1537                 else if (reject_reason)
1538                         ref->forced_update = 1;
1539         }
1540 }
1541
1542 static void set_merge(struct branch *ret)
1543 {
1544         struct remote *remote;
1545         char *ref;
1546         struct object_id oid;
1547         int i;
1548
1549         if (!ret)
1550                 return; /* no branch */
1551         if (ret->merge)
1552                 return; /* already run */
1553         if (!ret->remote_name || !ret->merge_nr) {
1554                 /*
1555                  * no merge config; let's make sure we don't confuse callers
1556                  * with a non-zero merge_nr but a NULL merge
1557                  */
1558                 ret->merge_nr = 0;
1559                 return;
1560         }
1561
1562         remote = remote_get(ret->remote_name);
1563
1564         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1565         for (i = 0; i < ret->merge_nr; i++) {
1566                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1567                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1568                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1569                     strcmp(ret->remote_name, "."))
1570                         continue;
1571                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1572                              &oid, &ref) == 1)
1573                         ret->merge[i]->dst = ref;
1574                 else
1575                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1576         }
1577 }
1578
1579 struct branch *branch_get(const char *name)
1580 {
1581         struct branch *ret;
1582
1583         read_config();
1584         if (!name || !*name || !strcmp(name, "HEAD"))
1585                 ret = current_branch;
1586         else
1587                 ret = make_branch(name, 0);
1588         set_merge(ret);
1589         return ret;
1590 }
1591
1592 int branch_has_merge_config(struct branch *branch)
1593 {
1594         return branch && !!branch->merge;
1595 }
1596
1597 int branch_merge_matches(struct branch *branch,
1598                                  int i,
1599                                  const char *refname)
1600 {
1601         if (!branch || i < 0 || i >= branch->merge_nr)
1602                 return 0;
1603         return refname_match(branch->merge[i]->src, refname);
1604 }
1605
1606 __attribute__((format (printf,2,3)))
1607 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1608 {
1609         if (err) {
1610                 va_list ap;
1611                 va_start(ap, fmt);
1612                 strbuf_vaddf(err, fmt, ap);
1613                 va_end(ap);
1614         }
1615         return NULL;
1616 }
1617
1618 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1619 {
1620         if (!branch)
1621                 return error_buf(err, _("HEAD does not point to a branch"));
1622
1623         if (!branch->merge || !branch->merge[0]) {
1624                 /*
1625                  * no merge config; is it because the user didn't define any,
1626                  * or because it is not a real branch, and get_branch
1627                  * auto-vivified it?
1628                  */
1629                 if (!ref_exists(branch->refname))
1630                         return error_buf(err, _("no such branch: '%s'"),
1631                                          branch->name);
1632                 return error_buf(err,
1633                                  _("no upstream configured for branch '%s'"),
1634                                  branch->name);
1635         }
1636
1637         if (!branch->merge[0]->dst)
1638                 return error_buf(err,
1639                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1640                                  branch->merge[0]->src);
1641
1642         return branch->merge[0]->dst;
1643 }
1644
1645 static const char *tracking_for_push_dest(struct remote *remote,
1646                                           const char *refname,
1647                                           struct strbuf *err)
1648 {
1649         char *ret;
1650
1651         ret = apply_refspecs(&remote->fetch, refname);
1652         if (!ret)
1653                 return error_buf(err,
1654                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1655                                  refname, remote->name);
1656         return ret;
1657 }
1658
1659 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1660 {
1661         struct remote *remote;
1662
1663         remote = remote_get(pushremote_for_branch(branch, NULL));
1664         if (!remote)
1665                 return error_buf(err,
1666                                  _("branch '%s' has no remote for pushing"),
1667                                  branch->name);
1668
1669         if (remote->push.nr) {
1670                 char *dst;
1671                 const char *ret;
1672
1673                 dst = apply_refspecs(&remote->push, branch->refname);
1674                 if (!dst)
1675                         return error_buf(err,
1676                                          _("push refspecs for '%s' do not include '%s'"),
1677                                          remote->name, branch->name);
1678
1679                 ret = tracking_for_push_dest(remote, dst, err);
1680                 free(dst);
1681                 return ret;
1682         }
1683
1684         if (remote->mirror)
1685                 return tracking_for_push_dest(remote, branch->refname, err);
1686
1687         switch (push_default) {
1688         case PUSH_DEFAULT_NOTHING:
1689                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1690
1691         case PUSH_DEFAULT_MATCHING:
1692         case PUSH_DEFAULT_CURRENT:
1693                 return tracking_for_push_dest(remote, branch->refname, err);
1694
1695         case PUSH_DEFAULT_UPSTREAM:
1696                 return branch_get_upstream(branch, err);
1697
1698         case PUSH_DEFAULT_UNSPECIFIED:
1699         case PUSH_DEFAULT_SIMPLE:
1700                 {
1701                         const char *up, *cur;
1702
1703                         up = branch_get_upstream(branch, err);
1704                         if (!up)
1705                                 return NULL;
1706                         cur = tracking_for_push_dest(remote, branch->refname, err);
1707                         if (!cur)
1708                                 return NULL;
1709                         if (strcmp(cur, up))
1710                                 return error_buf(err,
1711                                                  _("cannot resolve 'simple' push to a single destination"));
1712                         return cur;
1713                 }
1714         }
1715
1716         BUG("unhandled push situation");
1717 }
1718
1719 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1720 {
1721         if (!branch)
1722                 return error_buf(err, _("HEAD does not point to a branch"));
1723
1724         if (!branch->push_tracking_ref)
1725                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1726         return branch->push_tracking_ref;
1727 }
1728
1729 static int ignore_symref_update(const char *refname)
1730 {
1731         int flag;
1732
1733         if (!resolve_ref_unsafe(refname, 0, NULL, &flag))
1734                 return 0; /* non-existing refs are OK */
1735         return (flag & REF_ISSYMREF);
1736 }
1737
1738 /*
1739  * Create and return a list of (struct ref) consisting of copies of
1740  * each remote_ref that matches refspec.  refspec must be a pattern.
1741  * Fill in the copies' peer_ref to describe the local tracking refs to
1742  * which they map.  Omit any references that would map to an existing
1743  * local symbolic ref.
1744  */
1745 static struct ref *get_expanded_map(const struct ref *remote_refs,
1746                                     const struct refspec_item *refspec)
1747 {
1748         const struct ref *ref;
1749         struct ref *ret = NULL;
1750         struct ref **tail = &ret;
1751
1752         for (ref = remote_refs; ref; ref = ref->next) {
1753                 char *expn_name = NULL;
1754
1755                 if (strchr(ref->name, '^'))
1756                         continue; /* a dereference item */
1757                 if (match_name_with_pattern(refspec->src, ref->name,
1758                                             refspec->dst, &expn_name) &&
1759                     !ignore_symref_update(expn_name)) {
1760                         struct ref *cpy = copy_ref(ref);
1761
1762                         cpy->peer_ref = alloc_ref(expn_name);
1763                         if (refspec->force)
1764                                 cpy->peer_ref->force = 1;
1765                         *tail = cpy;
1766                         tail = &cpy->next;
1767                 }
1768                 free(expn_name);
1769         }
1770
1771         return ret;
1772 }
1773
1774 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1775 {
1776         const struct ref *ref;
1777         const struct ref *best_match = NULL;
1778         int best_score = 0;
1779
1780         for (ref = refs; ref; ref = ref->next) {
1781                 int score = refname_match(name, ref->name);
1782
1783                 if (best_score < score) {
1784                         best_match = ref;
1785                         best_score = score;
1786                 }
1787         }
1788         return best_match;
1789 }
1790
1791 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1792 {
1793         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1794
1795         if (!ref)
1796                 return NULL;
1797
1798         return copy_ref(ref);
1799 }
1800
1801 static struct ref *get_local_ref(const char *name)
1802 {
1803         if (!name || name[0] == '\0')
1804                 return NULL;
1805
1806         if (starts_with(name, "refs/"))
1807                 return alloc_ref(name);
1808
1809         if (starts_with(name, "heads/") ||
1810             starts_with(name, "tags/") ||
1811             starts_with(name, "remotes/"))
1812                 return alloc_ref_with_prefix("refs/", 5, name);
1813
1814         return alloc_ref_with_prefix("refs/heads/", 11, name);
1815 }
1816
1817 int get_fetch_map(const struct ref *remote_refs,
1818                   const struct refspec_item *refspec,
1819                   struct ref ***tail,
1820                   int missing_ok)
1821 {
1822         struct ref *ref_map, **rmp;
1823
1824         if (refspec->pattern) {
1825                 ref_map = get_expanded_map(remote_refs, refspec);
1826         } else {
1827                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1828
1829                 if (refspec->exact_sha1) {
1830                         ref_map = alloc_ref(name);
1831                         get_oid_hex(name, &ref_map->old_oid);
1832                         ref_map->exact_oid = 1;
1833                 } else {
1834                         ref_map = get_remote_ref(remote_refs, name);
1835                 }
1836                 if (!missing_ok && !ref_map)
1837                         die(_("couldn't find remote ref %s"), name);
1838                 if (ref_map) {
1839                         ref_map->peer_ref = get_local_ref(refspec->dst);
1840                         if (ref_map->peer_ref && refspec->force)
1841                                 ref_map->peer_ref->force = 1;
1842                 }
1843         }
1844
1845         for (rmp = &ref_map; *rmp; ) {
1846                 if ((*rmp)->peer_ref) {
1847                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1848                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1849                                 struct ref *ignore = *rmp;
1850                                 error(_("* Ignoring funny ref '%s' locally"),
1851                                       (*rmp)->peer_ref->name);
1852                                 *rmp = (*rmp)->next;
1853                                 free(ignore->peer_ref);
1854                                 free(ignore);
1855                                 continue;
1856                         }
1857                 }
1858                 rmp = &((*rmp)->next);
1859         }
1860
1861         if (ref_map)
1862                 tail_link_ref(ref_map, tail);
1863
1864         return 0;
1865 }
1866
1867 int resolve_remote_symref(struct ref *ref, struct ref *list)
1868 {
1869         if (!ref->symref)
1870                 return 0;
1871         for (; list; list = list->next)
1872                 if (!strcmp(ref->symref, list->name)) {
1873                         oidcpy(&ref->old_oid, &list->old_oid);
1874                         return 0;
1875                 }
1876         return 1;
1877 }
1878
1879 /*
1880  * Compute the commit ahead/behind values for the pair branch_name, base.
1881  *
1882  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1883  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1884  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1885  * set to zero).
1886  *
1887  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., ref
1888  * does not exist).  Returns 0 if the commits are identical.  Returns 1 if
1889  * commits are different.
1890  */
1891
1892 static int stat_branch_pair(const char *branch_name, const char *base,
1893                              int *num_ours, int *num_theirs,
1894                              enum ahead_behind_flags abf)
1895 {
1896         struct object_id oid;
1897         struct commit *ours, *theirs;
1898         struct rev_info revs;
1899         struct argv_array argv = ARGV_ARRAY_INIT;
1900
1901         /* Cannot stat if what we used to build on no longer exists */
1902         if (read_ref(base, &oid))
1903                 return -1;
1904         theirs = lookup_commit_reference(the_repository, &oid);
1905         if (!theirs)
1906                 return -1;
1907
1908         if (read_ref(branch_name, &oid))
1909                 return -1;
1910         ours = lookup_commit_reference(the_repository, &oid);
1911         if (!ours)
1912                 return -1;
1913
1914         *num_theirs = *num_ours = 0;
1915
1916         /* are we the same? */
1917         if (theirs == ours)
1918                 return 0;
1919         if (abf == AHEAD_BEHIND_QUICK)
1920                 return 1;
1921         if (abf != AHEAD_BEHIND_FULL)
1922                 BUG("stat_branch_pair: invalid abf '%d'", abf);
1923
1924         /* Run "rev-list --left-right ours...theirs" internally... */
1925         argv_array_push(&argv, ""); /* ignored */
1926         argv_array_push(&argv, "--left-right");
1927         argv_array_pushf(&argv, "%s...%s",
1928                          oid_to_hex(&ours->object.oid),
1929                          oid_to_hex(&theirs->object.oid));
1930         argv_array_push(&argv, "--");
1931
1932         repo_init_revisions(the_repository, &revs, NULL);
1933         setup_revisions(argv.argc, argv.argv, &revs, NULL);
1934         if (prepare_revision_walk(&revs))
1935                 die(_("revision walk setup failed"));
1936
1937         /* ... and count the commits on each side. */
1938         while (1) {
1939                 struct commit *c = get_revision(&revs);
1940                 if (!c)
1941                         break;
1942                 if (c->object.flags & SYMMETRIC_LEFT)
1943                         (*num_ours)++;
1944                 else
1945                         (*num_theirs)++;
1946         }
1947
1948         /* clear object flags smudged by the above traversal */
1949         clear_commit_marks(ours, ALL_REV_FLAGS);
1950         clear_commit_marks(theirs, ALL_REV_FLAGS);
1951
1952         argv_array_clear(&argv);
1953         return 1;
1954 }
1955
1956 /*
1957  * Lookup the tracking branch for the given branch and if present, optionally
1958  * compute the commit ahead/behind values for the pair.
1959  *
1960  * If for_push is true, the tracking branch refers to the push branch,
1961  * otherwise it refers to the upstream branch.
1962  *
1963  * The name of the tracking branch (or NULL if it is not defined) is
1964  * returned via *tracking_name, if it is not itself NULL.
1965  *
1966  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1967  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1968  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1969  * set to zero).
1970  *
1971  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1972  * upstream defined, or ref does not exist).  Returns 0 if the commits are
1973  * identical.  Returns 1 if commits are different.
1974  */
1975 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1976                        const char **tracking_name, int for_push,
1977                        enum ahead_behind_flags abf)
1978 {
1979         const char *base;
1980
1981         /* Cannot stat unless we are marked to build on top of somebody else. */
1982         base = for_push ? branch_get_push(branch, NULL) :
1983                 branch_get_upstream(branch, NULL);
1984         if (tracking_name)
1985                 *tracking_name = base;
1986         if (!base)
1987                 return -1;
1988
1989         return stat_branch_pair(branch->refname, base, num_ours, num_theirs, abf);
1990 }
1991
1992 /*
1993  * Return true when there is anything to report, otherwise false.
1994  */
1995 int format_tracking_info(struct branch *branch, struct strbuf *sb,
1996                          enum ahead_behind_flags abf)
1997 {
1998         int ours, theirs, sti;
1999         const char *full_base;
2000         char *base;
2001         int upstream_is_gone = 0;
2002
2003         sti = stat_tracking_info(branch, &ours, &theirs, &full_base, 0, abf);
2004         if (sti < 0) {
2005                 if (!full_base)
2006                         return 0;
2007                 upstream_is_gone = 1;
2008         }
2009
2010         base = shorten_unambiguous_ref(full_base, 0);
2011         if (upstream_is_gone) {
2012                 strbuf_addf(sb,
2013                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2014                         base);
2015                 if (advice_status_hints)
2016                         strbuf_addstr(sb,
2017                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2018         } else if (!sti) {
2019                 strbuf_addf(sb,
2020                         _("Your branch is up to date with '%s'.\n"),
2021                         base);
2022         } else if (abf == AHEAD_BEHIND_QUICK) {
2023                 strbuf_addf(sb,
2024                             _("Your branch and '%s' refer to different commits.\n"),
2025                             base);
2026                 if (advice_status_hints)
2027                         strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
2028                                     "git status --ahead-behind");
2029         } else if (!theirs) {
2030                 strbuf_addf(sb,
2031                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2032                            "Your branch is ahead of '%s' by %d commits.\n",
2033                            ours),
2034                         base, ours);
2035                 if (advice_status_hints)
2036                         strbuf_addstr(sb,
2037                                 _("  (use \"git push\" to publish your local commits)\n"));
2038         } else if (!ours) {
2039                 strbuf_addf(sb,
2040                         Q_("Your branch is behind '%s' by %d commit, "
2041                                "and can be fast-forwarded.\n",
2042                            "Your branch is behind '%s' by %d commits, "
2043                                "and can be fast-forwarded.\n",
2044                            theirs),
2045                         base, theirs);
2046                 if (advice_status_hints)
2047                         strbuf_addstr(sb,
2048                                 _("  (use \"git pull\" to update your local branch)\n"));
2049         } else {
2050                 strbuf_addf(sb,
2051                         Q_("Your branch and '%s' have diverged,\n"
2052                                "and have %d and %d different commit each, "
2053                                "respectively.\n",
2054                            "Your branch and '%s' have diverged,\n"
2055                                "and have %d and %d different commits each, "
2056                                "respectively.\n",
2057                            ours + theirs),
2058                         base, ours, theirs);
2059                 if (advice_status_hints)
2060                         strbuf_addstr(sb,
2061                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2062         }
2063         free(base);
2064         return 1;
2065 }
2066
2067 static int one_local_ref(const char *refname, const struct object_id *oid,
2068                          int flag, void *cb_data)
2069 {
2070         struct ref ***local_tail = cb_data;
2071         struct ref *ref;
2072
2073         /* we already know it starts with refs/ to get here */
2074         if (check_refname_format(refname + 5, 0))
2075                 return 0;
2076
2077         ref = alloc_ref(refname);
2078         oidcpy(&ref->new_oid, oid);
2079         **local_tail = ref;
2080         *local_tail = &ref->next;
2081         return 0;
2082 }
2083
2084 struct ref *get_local_heads(void)
2085 {
2086         struct ref *local_refs = NULL, **local_tail = &local_refs;
2087
2088         for_each_ref(one_local_ref, &local_tail);
2089         return local_refs;
2090 }
2091
2092 struct ref *guess_remote_head(const struct ref *head,
2093                               const struct ref *refs,
2094                               int all)
2095 {
2096         const struct ref *r;
2097         struct ref *list = NULL;
2098         struct ref **tail = &list;
2099
2100         if (!head)
2101                 return NULL;
2102
2103         /*
2104          * Some transports support directly peeking at
2105          * where HEAD points; if that is the case, then
2106          * we don't have to guess.
2107          */
2108         if (head->symref)
2109                 return copy_ref(find_ref_by_name(refs, head->symref));
2110
2111         /* If refs/heads/master could be right, it is. */
2112         if (!all) {
2113                 r = find_ref_by_name(refs, "refs/heads/master");
2114                 if (r && oideq(&r->old_oid, &head->old_oid))
2115                         return copy_ref(r);
2116         }
2117
2118         /* Look for another ref that points there */
2119         for (r = refs; r; r = r->next) {
2120                 if (r != head &&
2121                     starts_with(r->name, "refs/heads/") &&
2122                     oideq(&r->old_oid, &head->old_oid)) {
2123                         *tail = copy_ref(r);
2124                         tail = &((*tail)->next);
2125                         if (!all)
2126                                 break;
2127                 }
2128         }
2129
2130         return list;
2131 }
2132
2133 struct stale_heads_info {
2134         struct string_list *ref_names;
2135         struct ref **stale_refs_tail;
2136         struct refspec *rs;
2137 };
2138
2139 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2140                               int flags, void *cb_data)
2141 {
2142         struct stale_heads_info *info = cb_data;
2143         struct string_list matches = STRING_LIST_INIT_DUP;
2144         struct refspec_item query;
2145         int i, stale = 1;
2146         memset(&query, 0, sizeof(struct refspec_item));
2147         query.dst = (char *)refname;
2148
2149         query_refspecs_multiple(info->rs, &query, &matches);
2150         if (matches.nr == 0)
2151                 goto clean_exit; /* No matches */
2152
2153         /*
2154          * If we did find a suitable refspec and it's not a symref and
2155          * it's not in the list of refs that currently exist in that
2156          * remote, we consider it to be stale. In order to deal with
2157          * overlapping refspecs, we need to go over all of the
2158          * matching refs.
2159          */
2160         if (flags & REF_ISSYMREF)
2161                 goto clean_exit;
2162
2163         for (i = 0; stale && i < matches.nr; i++)
2164                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2165                         stale = 0;
2166
2167         if (stale) {
2168                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2169                 oidcpy(&ref->new_oid, oid);
2170         }
2171
2172 clean_exit:
2173         string_list_clear(&matches, 0);
2174         return 0;
2175 }
2176
2177 struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map)
2178 {
2179         struct ref *ref, *stale_refs = NULL;
2180         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2181         struct stale_heads_info info;
2182
2183         info.ref_names = &ref_names;
2184         info.stale_refs_tail = &stale_refs;
2185         info.rs = rs;
2186         for (ref = fetch_map; ref; ref = ref->next)
2187                 string_list_append(&ref_names, ref->name);
2188         string_list_sort(&ref_names);
2189         for_each_ref(get_stale_heads_cb, &info);
2190         string_list_clear(&ref_names, 0);
2191         return stale_refs;
2192 }
2193
2194 /*
2195  * Compare-and-swap
2196  */
2197 static void clear_cas_option(struct push_cas_option *cas)
2198 {
2199         int i;
2200
2201         for (i = 0; i < cas->nr; i++)
2202                 free(cas->entry[i].refname);
2203         free(cas->entry);
2204         memset(cas, 0, sizeof(*cas));
2205 }
2206
2207 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2208                                       const char *refname,
2209                                       size_t refnamelen)
2210 {
2211         struct push_cas *entry;
2212         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2213         entry = &cas->entry[cas->nr++];
2214         memset(entry, 0, sizeof(*entry));
2215         entry->refname = xmemdupz(refname, refnamelen);
2216         return entry;
2217 }
2218
2219 static int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2220 {
2221         const char *colon;
2222         struct push_cas *entry;
2223
2224         if (unset) {
2225                 /* "--no-<option>" */
2226                 clear_cas_option(cas);
2227                 return 0;
2228         }
2229
2230         if (!arg) {
2231                 /* just "--<option>" */
2232                 cas->use_tracking_for_rest = 1;
2233                 return 0;
2234         }
2235
2236         /* "--<option>=refname" or "--<option>=refname:value" */
2237         colon = strchrnul(arg, ':');
2238         entry = add_cas_entry(cas, arg, colon - arg);
2239         if (!*colon)
2240                 entry->use_tracking = 1;
2241         else if (!colon[1])
2242                 oidclr(&entry->expect);
2243         else if (get_oid(colon + 1, &entry->expect))
2244                 return error(_("cannot parse expected object name '%s'"),
2245                              colon + 1);
2246         return 0;
2247 }
2248
2249 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2250 {
2251         return parse_push_cas_option(opt->value, arg, unset);
2252 }
2253
2254 int is_empty_cas(const struct push_cas_option *cas)
2255 {
2256         return !cas->use_tracking_for_rest && !cas->nr;
2257 }
2258
2259 /*
2260  * Look at remote.fetch refspec and see if we have a remote
2261  * tracking branch for the refname there.  Fill its current
2262  * value in sha1[].
2263  * If we cannot do so, return negative to signal an error.
2264  */
2265 static int remote_tracking(struct remote *remote, const char *refname,
2266                            struct object_id *oid)
2267 {
2268         char *dst;
2269
2270         dst = apply_refspecs(&remote->fetch, refname);
2271         if (!dst)
2272                 return -1; /* no tracking ref for refname at remote */
2273         if (read_ref(dst, oid))
2274                 return -1; /* we know what the tracking ref is but we cannot read it */
2275         return 0;
2276 }
2277
2278 static void apply_cas(struct push_cas_option *cas,
2279                       struct remote *remote,
2280                       struct ref *ref)
2281 {
2282         int i;
2283
2284         /* Find an explicit --<option>=<name>[:<value>] entry */
2285         for (i = 0; i < cas->nr; i++) {
2286                 struct push_cas *entry = &cas->entry[i];
2287                 if (!refname_match(entry->refname, ref->name))
2288                         continue;
2289                 ref->expect_old_sha1 = 1;
2290                 if (!entry->use_tracking)
2291                         oidcpy(&ref->old_oid_expect, &entry->expect);
2292                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2293                         oidclr(&ref->old_oid_expect);
2294                 return;
2295         }
2296
2297         /* Are we using "--<option>" to cover all? */
2298         if (!cas->use_tracking_for_rest)
2299                 return;
2300
2301         ref->expect_old_sha1 = 1;
2302         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2303                 oidclr(&ref->old_oid_expect);
2304 }
2305
2306 void apply_push_cas(struct push_cas_option *cas,
2307                     struct remote *remote,
2308                     struct ref *remote_refs)
2309 {
2310         struct ref *ref;
2311         for (ref = remote_refs; ref; ref = ref->next)
2312                 apply_cas(cas, remote, ref);
2313 }