Merge branch 'es/outside-repo-errmsg-hints'
[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                                   int *explicit)
521 {
522         if (branch) {
523                 if (!for_push) {
524                         if (branch->merge_nr) {
525                                 if (explicit)
526                                         *explicit = 1;
527                                 return branch->merge_name[0];
528                         }
529                 } else {
530                         const char *dst, *remote_name =
531                                 pushremote_for_branch(branch, NULL);
532                         struct remote *remote = remote_get(remote_name);
533
534                         if (remote && remote->push.nr &&
535                             (dst = apply_refspecs(&remote->push,
536                                                   branch->refname))) {
537                                 if (explicit)
538                                         *explicit = 1;
539                                 return dst;
540                         }
541                 }
542         }
543         if (explicit)
544                 *explicit = 0;
545         return "";
546 }
547
548 static struct remote *remote_get_1(const char *name,
549                                    const char *(*get_default)(struct branch *, int *))
550 {
551         struct remote *ret;
552         int name_given = 0;
553
554         read_config();
555
556         if (name)
557                 name_given = 1;
558         else
559                 name = get_default(current_branch, &name_given);
560
561         ret = make_remote(name, 0);
562         if (valid_remote_nick(name) && have_git_dir()) {
563                 if (!valid_remote(ret))
564                         read_remotes_file(ret);
565                 if (!valid_remote(ret))
566                         read_branches_file(ret);
567         }
568         if (name_given && !valid_remote(ret))
569                 add_url_alias(ret, name);
570         if (!valid_remote(ret))
571                 return NULL;
572         return ret;
573 }
574
575 struct remote *remote_get(const char *name)
576 {
577         return remote_get_1(name, remote_for_branch);
578 }
579
580 struct remote *pushremote_get(const char *name)
581 {
582         return remote_get_1(name, pushremote_for_branch);
583 }
584
585 int remote_is_configured(struct remote *remote, int in_repo)
586 {
587         if (!remote)
588                 return 0;
589         if (in_repo)
590                 return remote->configured_in_repo;
591         return !!remote->origin;
592 }
593
594 int for_each_remote(each_remote_fn fn, void *priv)
595 {
596         int i, result = 0;
597         read_config();
598         for (i = 0; i < remotes_nr && !result; i++) {
599                 struct remote *r = remotes[i];
600                 if (!r)
601                         continue;
602                 result = fn(r, priv);
603         }
604         return result;
605 }
606
607 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
608 {
609         if (strcmp(ref1->name, ref2->name)) {
610                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
611                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
612                         die(_("Cannot fetch both %s and %s to %s"),
613                             ref1->name, ref2->name, ref2->peer_ref->name);
614                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
615                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
616                         warning(_("%s usually tracks %s, not %s"),
617                                 ref2->peer_ref->name, ref2->name, ref1->name);
618                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
619                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
620                         die(_("%s tracks both %s and %s"),
621                             ref2->peer_ref->name, ref1->name, ref2->name);
622                 } else {
623                         /*
624                          * This last possibility doesn't occur because
625                          * FETCH_HEAD_IGNORE entries always appear at
626                          * the end of the list.
627                          */
628                         BUG("Internal error");
629                 }
630         }
631         free(ref2->peer_ref);
632         free(ref2);
633 }
634
635 struct ref *ref_remove_duplicates(struct ref *ref_map)
636 {
637         struct string_list refs = STRING_LIST_INIT_NODUP;
638         struct ref *retval = NULL;
639         struct ref **p = &retval;
640
641         while (ref_map) {
642                 struct ref *ref = ref_map;
643
644                 ref_map = ref_map->next;
645                 ref->next = NULL;
646
647                 if (!ref->peer_ref) {
648                         *p = ref;
649                         p = &ref->next;
650                 } else {
651                         struct string_list_item *item =
652                                 string_list_insert(&refs, ref->peer_ref->name);
653
654                         if (item->util) {
655                                 /* Entry already existed */
656                                 handle_duplicate((struct ref *)item->util, ref);
657                         } else {
658                                 *p = ref;
659                                 p = &ref->next;
660                                 item->util = ref;
661                         }
662                 }
663         }
664
665         string_list_clear(&refs, 0);
666         return retval;
667 }
668
669 int remote_has_url(struct remote *remote, const char *url)
670 {
671         int i;
672         for (i = 0; i < remote->url_nr; i++) {
673                 if (!strcmp(remote->url[i], url))
674                         return 1;
675         }
676         return 0;
677 }
678
679 static int match_name_with_pattern(const char *key, const char *name,
680                                    const char *value, char **result)
681 {
682         const char *kstar = strchr(key, '*');
683         size_t klen;
684         size_t ksuffixlen;
685         size_t namelen;
686         int ret;
687         if (!kstar)
688                 die(_("key '%s' of pattern had no '*'"), key);
689         klen = kstar - key;
690         ksuffixlen = strlen(kstar + 1);
691         namelen = strlen(name);
692         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
693                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
694         if (ret && value) {
695                 struct strbuf sb = STRBUF_INIT;
696                 const char *vstar = strchr(value, '*');
697                 if (!vstar)
698                         die(_("value '%s' of pattern has no '*'"), value);
699                 strbuf_add(&sb, value, vstar - value);
700                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
701                 strbuf_addstr(&sb, vstar + 1);
702                 *result = strbuf_detach(&sb, NULL);
703         }
704         return ret;
705 }
706
707 static void query_refspecs_multiple(struct refspec *rs,
708                                     struct refspec_item *query,
709                                     struct string_list *results)
710 {
711         int i;
712         int find_src = !query->src;
713
714         if (find_src && !query->dst)
715                 BUG("query_refspecs_multiple: need either src or dst");
716
717         for (i = 0; i < rs->nr; i++) {
718                 struct refspec_item *refspec = &rs->items[i];
719                 const char *key = find_src ? refspec->dst : refspec->src;
720                 const char *value = find_src ? refspec->src : refspec->dst;
721                 const char *needle = find_src ? query->dst : query->src;
722                 char **result = find_src ? &query->src : &query->dst;
723
724                 if (!refspec->dst)
725                         continue;
726                 if (refspec->pattern) {
727                         if (match_name_with_pattern(key, needle, value, result))
728                                 string_list_append_nodup(results, *result);
729                 } else if (!strcmp(needle, key)) {
730                         string_list_append(results, value);
731                 }
732         }
733 }
734
735 int query_refspecs(struct refspec *rs, struct refspec_item *query)
736 {
737         int i;
738         int find_src = !query->src;
739         const char *needle = find_src ? query->dst : query->src;
740         char **result = find_src ? &query->src : &query->dst;
741
742         if (find_src && !query->dst)
743                 BUG("query_refspecs: need either src or dst");
744
745         for (i = 0; i < rs->nr; i++) {
746                 struct refspec_item *refspec = &rs->items[i];
747                 const char *key = find_src ? refspec->dst : refspec->src;
748                 const char *value = find_src ? refspec->src : refspec->dst;
749
750                 if (!refspec->dst)
751                         continue;
752                 if (refspec->pattern) {
753                         if (match_name_with_pattern(key, needle, value, result)) {
754                                 query->force = refspec->force;
755                                 return 0;
756                         }
757                 } else if (!strcmp(needle, key)) {
758                         *result = xstrdup(value);
759                         query->force = refspec->force;
760                         return 0;
761                 }
762         }
763         return -1;
764 }
765
766 char *apply_refspecs(struct refspec *rs, const char *name)
767 {
768         struct refspec_item query;
769
770         memset(&query, 0, sizeof(struct refspec_item));
771         query.src = (char *)name;
772
773         if (query_refspecs(rs, &query))
774                 return NULL;
775
776         return query.dst;
777 }
778
779 int remote_find_tracking(struct remote *remote, struct refspec_item *refspec)
780 {
781         return query_refspecs(&remote->fetch, refspec);
782 }
783
784 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
785                 const char *name)
786 {
787         size_t len = strlen(name);
788         struct ref *ref = xcalloc(1, st_add4(sizeof(*ref), prefixlen, len, 1));
789         memcpy(ref->name, prefix, prefixlen);
790         memcpy(ref->name + prefixlen, name, len);
791         return ref;
792 }
793
794 struct ref *alloc_ref(const char *name)
795 {
796         return alloc_ref_with_prefix("", 0, name);
797 }
798
799 struct ref *copy_ref(const struct ref *ref)
800 {
801         struct ref *cpy;
802         size_t len;
803         if (!ref)
804                 return NULL;
805         len = st_add3(sizeof(struct ref), strlen(ref->name), 1);
806         cpy = xmalloc(len);
807         memcpy(cpy, ref, len);
808         cpy->next = NULL;
809         cpy->symref = xstrdup_or_null(ref->symref);
810         cpy->remote_status = xstrdup_or_null(ref->remote_status);
811         cpy->peer_ref = copy_ref(ref->peer_ref);
812         return cpy;
813 }
814
815 struct ref *copy_ref_list(const struct ref *ref)
816 {
817         struct ref *ret = NULL;
818         struct ref **tail = &ret;
819         while (ref) {
820                 *tail = copy_ref(ref);
821                 ref = ref->next;
822                 tail = &((*tail)->next);
823         }
824         return ret;
825 }
826
827 void free_one_ref(struct ref *ref)
828 {
829         if (!ref)
830                 return;
831         free_one_ref(ref->peer_ref);
832         free(ref->remote_status);
833         free(ref->symref);
834         free(ref);
835 }
836
837 void free_refs(struct ref *ref)
838 {
839         struct ref *next;
840         while (ref) {
841                 next = ref->next;
842                 free_one_ref(ref);
843                 ref = next;
844         }
845 }
846
847 int ref_compare_name(const void *va, const void *vb)
848 {
849         const struct ref *a = va, *b = vb;
850         return strcmp(a->name, b->name);
851 }
852
853 static void *ref_list_get_next(const void *a)
854 {
855         return ((const struct ref *)a)->next;
856 }
857
858 static void ref_list_set_next(void *a, void *next)
859 {
860         ((struct ref *)a)->next = next;
861 }
862
863 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
864 {
865         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
866 }
867
868 int count_refspec_match(const char *pattern,
869                         struct ref *refs,
870                         struct ref **matched_ref)
871 {
872         int patlen = strlen(pattern);
873         struct ref *matched_weak = NULL;
874         struct ref *matched = NULL;
875         int weak_match = 0;
876         int match = 0;
877
878         for (weak_match = match = 0; refs; refs = refs->next) {
879                 char *name = refs->name;
880                 int namelen = strlen(name);
881
882                 if (!refname_match(pattern, name))
883                         continue;
884
885                 /* A match is "weak" if it is with refs outside
886                  * heads or tags, and did not specify the pattern
887                  * in full (e.g. "refs/remotes/origin/master") or at
888                  * least from the toplevel (e.g. "remotes/origin/master");
889                  * otherwise "git push $URL master" would result in
890                  * ambiguity between remotes/origin/master and heads/master
891                  * at the remote site.
892                  */
893                 if (namelen != patlen &&
894                     patlen != namelen - 5 &&
895                     !starts_with(name, "refs/heads/") &&
896                     !starts_with(name, "refs/tags/")) {
897                         /* We want to catch the case where only weak
898                          * matches are found and there are multiple
899                          * matches, and where more than one strong
900                          * matches are found, as ambiguous.  One
901                          * strong match with zero or more weak matches
902                          * are acceptable as a unique match.
903                          */
904                         matched_weak = refs;
905                         weak_match++;
906                 }
907                 else {
908                         matched = refs;
909                         match++;
910                 }
911         }
912         if (!matched) {
913                 if (matched_ref)
914                         *matched_ref = matched_weak;
915                 return weak_match;
916         }
917         else {
918                 if (matched_ref)
919                         *matched_ref = matched;
920                 return match;
921         }
922 }
923
924 static void tail_link_ref(struct ref *ref, struct ref ***tail)
925 {
926         **tail = ref;
927         while (ref->next)
928                 ref = ref->next;
929         *tail = &ref->next;
930 }
931
932 static struct ref *alloc_delete_ref(void)
933 {
934         struct ref *ref = alloc_ref("(delete)");
935         oidclr(&ref->new_oid);
936         return ref;
937 }
938
939 static int try_explicit_object_name(const char *name,
940                                     struct ref **match)
941 {
942         struct object_id oid;
943
944         if (!*name) {
945                 if (match)
946                         *match = alloc_delete_ref();
947                 return 0;
948         }
949
950         if (get_oid(name, &oid))
951                 return -1;
952
953         if (match) {
954                 *match = alloc_ref(name);
955                 oidcpy(&(*match)->new_oid, &oid);
956         }
957         return 0;
958 }
959
960 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
961 {
962         struct ref *ret = alloc_ref(name);
963         tail_link_ref(ret, tail);
964         return ret;
965 }
966
967 static char *guess_ref(const char *name, struct ref *peer)
968 {
969         struct strbuf buf = STRBUF_INIT;
970
971         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
972                                            NULL, NULL);
973         if (!r)
974                 return NULL;
975
976         if (starts_with(r, "refs/heads/")) {
977                 strbuf_addstr(&buf, "refs/heads/");
978         } else if (starts_with(r, "refs/tags/")) {
979                 strbuf_addstr(&buf, "refs/tags/");
980         } else {
981                 return NULL;
982         }
983
984         strbuf_addstr(&buf, name);
985         return strbuf_detach(&buf, NULL);
986 }
987
988 static int match_explicit_lhs(struct ref *src,
989                               struct refspec_item *rs,
990                               struct ref **match,
991                               int *allocated_match)
992 {
993         switch (count_refspec_match(rs->src, src, match)) {
994         case 1:
995                 if (allocated_match)
996                         *allocated_match = 0;
997                 return 0;
998         case 0:
999                 /* The source could be in the get_sha1() format
1000                  * not a reference name.  :refs/other is a
1001                  * way to delete 'other' ref at the remote end.
1002                  */
1003                 if (try_explicit_object_name(rs->src, match) < 0)
1004                         return error(_("src refspec %s does not match any"), rs->src);
1005                 if (allocated_match)
1006                         *allocated_match = 1;
1007                 return 0;
1008         default:
1009                 return error(_("src refspec %s matches more than one"), rs->src);
1010         }
1011 }
1012
1013 static void show_push_unqualified_ref_name_error(const char *dst_value,
1014                                                  const char *matched_src_name)
1015 {
1016         struct object_id oid;
1017         enum object_type type;
1018
1019         /*
1020          * TRANSLATORS: "matches '%s'%" is the <dst> part of "git push
1021          * <remote> <src>:<dst>" push, and "being pushed ('%s')" is
1022          * the <src>.
1023          */
1024         error(_("The destination you provided is not a full refname (i.e.,\n"
1025                 "starting with \"refs/\"). We tried to guess what you meant by:\n"
1026                 "\n"
1027                 "- Looking for a ref that matches '%s' on the remote side.\n"
1028                 "- Checking if the <src> being pushed ('%s')\n"
1029                 "  is a ref in \"refs/{heads,tags}/\". If so we add a corresponding\n"
1030                 "  refs/{heads,tags}/ prefix on the remote side.\n"
1031                 "\n"
1032                 "Neither worked, so we gave up. You must fully qualify the ref."),
1033               dst_value, matched_src_name);
1034
1035         if (!advice_push_unqualified_ref_name)
1036                 return;
1037
1038         if (get_oid(matched_src_name, &oid))
1039                 BUG("'%s' is not a valid object, "
1040                     "match_explicit_lhs() should catch this!",
1041                     matched_src_name);
1042         type = oid_object_info(the_repository, &oid, NULL);
1043         if (type == OBJ_COMMIT) {
1044                 advise(_("The <src> part of the refspec is a commit object.\n"
1045                          "Did you mean to create a new branch by pushing to\n"
1046                          "'%s:refs/heads/%s'?"),
1047                        matched_src_name, dst_value);
1048         } else if (type == OBJ_TAG) {
1049                 advise(_("The <src> part of the refspec is a tag object.\n"
1050                          "Did you mean to create a new tag by pushing to\n"
1051                          "'%s:refs/tags/%s'?"),
1052                        matched_src_name, dst_value);
1053         } else if (type == OBJ_TREE) {
1054                 advise(_("The <src> part of the refspec is a tree object.\n"
1055                          "Did you mean to tag a new tree by pushing to\n"
1056                          "'%s:refs/tags/%s'?"),
1057                        matched_src_name, dst_value);
1058         } else if (type == OBJ_BLOB) {
1059                 advise(_("The <src> part of the refspec is a blob object.\n"
1060                          "Did you mean to tag a new blob by pushing to\n"
1061                          "'%s:refs/tags/%s'?"),
1062                        matched_src_name, dst_value);
1063         } else {
1064                 BUG("'%s' should be commit/tag/tree/blob, is '%d'",
1065                     matched_src_name, type);
1066         }
1067 }
1068
1069 static int match_explicit(struct ref *src, struct ref *dst,
1070                           struct ref ***dst_tail,
1071                           struct refspec_item *rs)
1072 {
1073         struct ref *matched_src, *matched_dst;
1074         int allocated_src;
1075
1076         const char *dst_value = rs->dst;
1077         char *dst_guess;
1078
1079         if (rs->pattern || rs->matching)
1080                 return 0;
1081
1082         matched_src = matched_dst = NULL;
1083         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1084                 return -1;
1085
1086         if (!dst_value) {
1087                 int flag;
1088
1089                 dst_value = resolve_ref_unsafe(matched_src->name,
1090                                                RESOLVE_REF_READING,
1091                                                NULL, &flag);
1092                 if (!dst_value ||
1093                     ((flag & REF_ISSYMREF) &&
1094                      !starts_with(dst_value, "refs/heads/")))
1095                         die(_("%s cannot be resolved to branch"),
1096                             matched_src->name);
1097         }
1098
1099         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1100         case 1:
1101                 break;
1102         case 0:
1103                 if (starts_with(dst_value, "refs/")) {
1104                         matched_dst = make_linked_ref(dst_value, dst_tail);
1105                 } else if (is_null_oid(&matched_src->new_oid)) {
1106                         error(_("unable to delete '%s': remote ref does not exist"),
1107                               dst_value);
1108                 } else if ((dst_guess = guess_ref(dst_value, matched_src))) {
1109                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1110                         free(dst_guess);
1111                 } else {
1112                         show_push_unqualified_ref_name_error(dst_value,
1113                                                              matched_src->name);
1114                 }
1115                 break;
1116         default:
1117                 matched_dst = NULL;
1118                 error(_("dst refspec %s matches more than one"),
1119                       dst_value);
1120                 break;
1121         }
1122         if (!matched_dst)
1123                 return -1;
1124         if (matched_dst->peer_ref)
1125                 return error(_("dst ref %s receives from more than one src"),
1126                              matched_dst->name);
1127         else {
1128                 matched_dst->peer_ref = allocated_src ?
1129                                         matched_src :
1130                                         copy_ref(matched_src);
1131                 matched_dst->force = rs->force;
1132         }
1133         return 0;
1134 }
1135
1136 static int match_explicit_refs(struct ref *src, struct ref *dst,
1137                                struct ref ***dst_tail, struct refspec *rs)
1138 {
1139         int i, errs;
1140         for (i = errs = 0; i < rs->nr; i++)
1141                 errs += match_explicit(src, dst, dst_tail, &rs->items[i]);
1142         return errs;
1143 }
1144
1145 static char *get_ref_match(const struct refspec *rs, const struct ref *ref,
1146                            int send_mirror, int direction,
1147                            const struct refspec_item **ret_pat)
1148 {
1149         const struct refspec_item *pat;
1150         char *name;
1151         int i;
1152         int matching_refs = -1;
1153         for (i = 0; i < rs->nr; i++) {
1154                 const struct refspec_item *item = &rs->items[i];
1155                 if (item->matching &&
1156                     (matching_refs == -1 || item->force)) {
1157                         matching_refs = i;
1158                         continue;
1159                 }
1160
1161                 if (item->pattern) {
1162                         const char *dst_side = item->dst ? item->dst : item->src;
1163                         int match;
1164                         if (direction == FROM_SRC)
1165                                 match = match_name_with_pattern(item->src, ref->name, dst_side, &name);
1166                         else
1167                                 match = match_name_with_pattern(dst_side, ref->name, item->src, &name);
1168                         if (match) {
1169                                 matching_refs = i;
1170                                 break;
1171                         }
1172                 }
1173         }
1174         if (matching_refs == -1)
1175                 return NULL;
1176
1177         pat = &rs->items[matching_refs];
1178         if (pat->matching) {
1179                 /*
1180                  * "matching refs"; traditionally we pushed everything
1181                  * including refs outside refs/heads/ hierarchy, but
1182                  * that does not make much sense these days.
1183                  */
1184                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1185                         return NULL;
1186                 name = xstrdup(ref->name);
1187         }
1188         if (ret_pat)
1189                 *ret_pat = pat;
1190         return name;
1191 }
1192
1193 static struct ref **tail_ref(struct ref **head)
1194 {
1195         struct ref **tail = head;
1196         while (*tail)
1197                 tail = &((*tail)->next);
1198         return tail;
1199 }
1200
1201 struct tips {
1202         struct commit **tip;
1203         int nr, alloc;
1204 };
1205
1206 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1207 {
1208         struct commit *commit;
1209
1210         if (is_null_oid(oid))
1211                 return;
1212         commit = lookup_commit_reference_gently(the_repository, oid, 1);
1213         if (!commit || (commit->object.flags & TMP_MARK))
1214                 return;
1215         commit->object.flags |= TMP_MARK;
1216         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1217         tips->tip[tips->nr++] = commit;
1218 }
1219
1220 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1221 {
1222         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1223         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1224         struct string_list_item *item;
1225         struct ref *ref;
1226         struct tips sent_tips;
1227
1228         /*
1229          * Collect everything we know they would have at the end of
1230          * this push, and collect all tags they have.
1231          */
1232         memset(&sent_tips, 0, sizeof(sent_tips));
1233         for (ref = *dst; ref; ref = ref->next) {
1234                 if (ref->peer_ref &&
1235                     !is_null_oid(&ref->peer_ref->new_oid))
1236                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1237                 else
1238                         add_to_tips(&sent_tips, &ref->old_oid);
1239                 if (starts_with(ref->name, "refs/tags/"))
1240                         string_list_append(&dst_tag, ref->name);
1241         }
1242         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1243
1244         string_list_sort(&dst_tag);
1245
1246         /* Collect tags they do not have. */
1247         for (ref = src; ref; ref = ref->next) {
1248                 if (!starts_with(ref->name, "refs/tags/"))
1249                         continue; /* not a tag */
1250                 if (string_list_has_string(&dst_tag, ref->name))
1251                         continue; /* they already have it */
1252                 if (oid_object_info(the_repository, &ref->new_oid, NULL) != OBJ_TAG)
1253                         continue; /* be conservative */
1254                 item = string_list_append(&src_tag, ref->name);
1255                 item->util = ref;
1256         }
1257         string_list_clear(&dst_tag, 0);
1258
1259         /*
1260          * At this point, src_tag lists tags that are missing from
1261          * dst, and sent_tips lists the tips we are pushing or those
1262          * that we know they already have. An element in the src_tag
1263          * that is an ancestor of any of the sent_tips needs to be
1264          * sent to the other side.
1265          */
1266         if (sent_tips.nr) {
1267                 const int reachable_flag = 1;
1268                 struct commit_list *found_commits;
1269                 struct commit **src_commits;
1270                 int nr_src_commits = 0, alloc_src_commits = 16;
1271                 ALLOC_ARRAY(src_commits, alloc_src_commits);
1272
1273                 for_each_string_list_item(item, &src_tag) {
1274                         struct ref *ref = item->util;
1275                         struct commit *commit;
1276
1277                         if (is_null_oid(&ref->new_oid))
1278                                 continue;
1279                         commit = lookup_commit_reference_gently(the_repository,
1280                                                                 &ref->new_oid,
1281                                                                 1);
1282                         if (!commit)
1283                                 /* not pushing a commit, which is not an error */
1284                                 continue;
1285
1286                         ALLOC_GROW(src_commits, nr_src_commits + 1, alloc_src_commits);
1287                         src_commits[nr_src_commits++] = commit;
1288                 }
1289
1290                 found_commits = get_reachable_subset(sent_tips.tip, sent_tips.nr,
1291                                                      src_commits, nr_src_commits,
1292                                                      reachable_flag);
1293
1294                 for_each_string_list_item(item, &src_tag) {
1295                         struct ref *dst_ref;
1296                         struct ref *ref = item->util;
1297                         struct commit *commit;
1298
1299                         if (is_null_oid(&ref->new_oid))
1300                                 continue;
1301                         commit = lookup_commit_reference_gently(the_repository,
1302                                                                 &ref->new_oid,
1303                                                                 1);
1304                         if (!commit)
1305                                 /* not pushing a commit, which is not an error */
1306                                 continue;
1307
1308                         /*
1309                          * Is this tag, which they do not have, reachable from
1310                          * any of the commits we are sending?
1311                          */
1312                         if (!(commit->object.flags & reachable_flag))
1313                                 continue;
1314
1315                         /* Add it in */
1316                         dst_ref = make_linked_ref(ref->name, dst_tail);
1317                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1318                         dst_ref->peer_ref = copy_ref(ref);
1319                 }
1320
1321                 clear_commit_marks_many(nr_src_commits, src_commits, reachable_flag);
1322                 free(src_commits);
1323                 free_commit_list(found_commits);
1324         }
1325
1326         string_list_clear(&src_tag, 0);
1327         free(sent_tips.tip);
1328 }
1329
1330 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1331 {
1332         for ( ; list; list = list->next)
1333                 if (!strcmp(list->name, name))
1334                         return (struct ref *)list;
1335         return NULL;
1336 }
1337
1338 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1339 {
1340         for ( ; ref; ref = ref->next)
1341                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1342
1343         string_list_sort(ref_index);
1344 }
1345
1346 /*
1347  * Given only the set of local refs, sanity-check the set of push
1348  * refspecs. We can't catch all errors that match_push_refs would,
1349  * but we can catch some errors early before even talking to the
1350  * remote side.
1351  */
1352 int check_push_refs(struct ref *src, struct refspec *rs)
1353 {
1354         int ret = 0;
1355         int i;
1356
1357         for (i = 0; i < rs->nr; i++) {
1358                 struct refspec_item *item = &rs->items[i];
1359
1360                 if (item->pattern || item->matching)
1361                         continue;
1362
1363                 ret |= match_explicit_lhs(src, item, NULL, NULL);
1364         }
1365
1366         return ret;
1367 }
1368
1369 /*
1370  * Given the set of refs the local repository has, the set of refs the
1371  * remote repository has, and the refspec used for push, determine
1372  * what remote refs we will update and with what value by setting
1373  * peer_ref (which object is being pushed) and force (if the push is
1374  * forced) in elements of "dst". The function may add new elements to
1375  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1376  */
1377 int match_push_refs(struct ref *src, struct ref **dst,
1378                     struct refspec *rs, int flags)
1379 {
1380         int send_all = flags & MATCH_REFS_ALL;
1381         int send_mirror = flags & MATCH_REFS_MIRROR;
1382         int send_prune = flags & MATCH_REFS_PRUNE;
1383         int errs;
1384         struct ref *ref, **dst_tail = tail_ref(dst);
1385         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1386
1387         /* If no refspec is provided, use the default ":" */
1388         if (!rs->nr)
1389                 refspec_append(rs, ":");
1390
1391         errs = match_explicit_refs(src, *dst, &dst_tail, rs);
1392
1393         /* pick the remainder */
1394         for (ref = src; ref; ref = ref->next) {
1395                 struct string_list_item *dst_item;
1396                 struct ref *dst_peer;
1397                 const struct refspec_item *pat = NULL;
1398                 char *dst_name;
1399
1400                 dst_name = get_ref_match(rs, ref, send_mirror, FROM_SRC, &pat);
1401                 if (!dst_name)
1402                         continue;
1403
1404                 if (!dst_ref_index.nr)
1405                         prepare_ref_index(&dst_ref_index, *dst);
1406
1407                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1408                 dst_peer = dst_item ? dst_item->util : NULL;
1409                 if (dst_peer) {
1410                         if (dst_peer->peer_ref)
1411                                 /* We're already sending something to this ref. */
1412                                 goto free_name;
1413                 } else {
1414                         if (pat->matching && !(send_all || send_mirror))
1415                                 /*
1416                                  * Remote doesn't have it, and we have no
1417                                  * explicit pattern, and we don't have
1418                                  * --all or --mirror.
1419                                  */
1420                                 goto free_name;
1421
1422                         /* Create a new one and link it */
1423                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1424                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1425                         string_list_insert(&dst_ref_index,
1426                                 dst_peer->name)->util = dst_peer;
1427                 }
1428                 dst_peer->peer_ref = copy_ref(ref);
1429                 dst_peer->force = pat->force;
1430         free_name:
1431                 free(dst_name);
1432         }
1433
1434         string_list_clear(&dst_ref_index, 0);
1435
1436         if (flags & MATCH_REFS_FOLLOW_TAGS)
1437                 add_missing_tags(src, dst, &dst_tail);
1438
1439         if (send_prune) {
1440                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1441                 /* check for missing refs on the remote */
1442                 for (ref = *dst; ref; ref = ref->next) {
1443                         char *src_name;
1444
1445                         if (ref->peer_ref)
1446                                 /* We're already sending something to this ref. */
1447                                 continue;
1448
1449                         src_name = get_ref_match(rs, ref, send_mirror, FROM_DST, NULL);
1450                         if (src_name) {
1451                                 if (!src_ref_index.nr)
1452                                         prepare_ref_index(&src_ref_index, src);
1453                                 if (!string_list_has_string(&src_ref_index,
1454                                             src_name))
1455                                         ref->peer_ref = alloc_delete_ref();
1456                                 free(src_name);
1457                         }
1458                 }
1459                 string_list_clear(&src_ref_index, 0);
1460         }
1461
1462         if (errs)
1463                 return -1;
1464         return 0;
1465 }
1466
1467 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1468                              int force_update)
1469 {
1470         struct ref *ref;
1471
1472         for (ref = remote_refs; ref; ref = ref->next) {
1473                 int force_ref_update = ref->force || force_update;
1474                 int reject_reason = 0;
1475
1476                 if (ref->peer_ref)
1477                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1478                 else if (!send_mirror)
1479                         continue;
1480
1481                 ref->deletion = is_null_oid(&ref->new_oid);
1482                 if (!ref->deletion &&
1483                         oideq(&ref->old_oid, &ref->new_oid)) {
1484                         ref->status = REF_STATUS_UPTODATE;
1485                         continue;
1486                 }
1487
1488                 /*
1489                  * If the remote ref has moved and is now different
1490                  * from what we expect, reject any push.
1491                  *
1492                  * It also is an error if the user told us to check
1493                  * with the remote-tracking branch to find the value
1494                  * to expect, but we did not have such a tracking
1495                  * branch.
1496                  */
1497                 if (ref->expect_old_sha1) {
1498                         if (!oideq(&ref->old_oid, &ref->old_oid_expect))
1499                                 reject_reason = REF_STATUS_REJECT_STALE;
1500                         else
1501                                 /* If the ref isn't stale then force the update. */
1502                                 force_ref_update = 1;
1503                 }
1504
1505                 /*
1506                  * If the update isn't already rejected then check
1507                  * the usual "must fast-forward" rules.
1508                  *
1509                  * Decide whether an individual refspec A:B can be
1510                  * pushed.  The push will succeed if any of the
1511                  * following are true:
1512                  *
1513                  * (1) the remote reference B does not exist
1514                  *
1515                  * (2) the remote reference B is being removed (i.e.,
1516                  *     pushing :B where no source is specified)
1517                  *
1518                  * (3) the destination is not under refs/tags/, and
1519                  *     if the old and new value is a commit, the new
1520                  *     is a descendant of the old.
1521                  *
1522                  * (4) it is forced using the +A:B notation, or by
1523                  *     passing the --force argument
1524                  */
1525
1526                 if (!reject_reason && !ref->deletion && !is_null_oid(&ref->old_oid)) {
1527                         if (starts_with(ref->name, "refs/tags/"))
1528                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1529                         else if (!has_object_file(&ref->old_oid))
1530                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1531                         else if (!lookup_commit_reference_gently(the_repository, &ref->old_oid, 1) ||
1532                                  !lookup_commit_reference_gently(the_repository, &ref->new_oid, 1))
1533                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1534                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1535                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1536                 }
1537
1538                 /*
1539                  * "--force" will defeat any rejection implemented
1540                  * by the rules above.
1541                  */
1542                 if (!force_ref_update)
1543                         ref->status = reject_reason;
1544                 else if (reject_reason)
1545                         ref->forced_update = 1;
1546         }
1547 }
1548
1549 static void set_merge(struct branch *ret)
1550 {
1551         struct remote *remote;
1552         char *ref;
1553         struct object_id oid;
1554         int i;
1555
1556         if (!ret)
1557                 return; /* no branch */
1558         if (ret->merge)
1559                 return; /* already run */
1560         if (!ret->remote_name || !ret->merge_nr) {
1561                 /*
1562                  * no merge config; let's make sure we don't confuse callers
1563                  * with a non-zero merge_nr but a NULL merge
1564                  */
1565                 ret->merge_nr = 0;
1566                 return;
1567         }
1568
1569         remote = remote_get(ret->remote_name);
1570
1571         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1572         for (i = 0; i < ret->merge_nr; i++) {
1573                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1574                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1575                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1576                     strcmp(ret->remote_name, "."))
1577                         continue;
1578                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1579                              &oid, &ref) == 1)
1580                         ret->merge[i]->dst = ref;
1581                 else
1582                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1583         }
1584 }
1585
1586 struct branch *branch_get(const char *name)
1587 {
1588         struct branch *ret;
1589
1590         read_config();
1591         if (!name || !*name || !strcmp(name, "HEAD"))
1592                 ret = current_branch;
1593         else
1594                 ret = make_branch(name, 0);
1595         set_merge(ret);
1596         return ret;
1597 }
1598
1599 int branch_has_merge_config(struct branch *branch)
1600 {
1601         return branch && !!branch->merge;
1602 }
1603
1604 int branch_merge_matches(struct branch *branch,
1605                                  int i,
1606                                  const char *refname)
1607 {
1608         if (!branch || i < 0 || i >= branch->merge_nr)
1609                 return 0;
1610         return refname_match(branch->merge[i]->src, refname);
1611 }
1612
1613 __attribute__((format (printf,2,3)))
1614 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1615 {
1616         if (err) {
1617                 va_list ap;
1618                 va_start(ap, fmt);
1619                 strbuf_vaddf(err, fmt, ap);
1620                 va_end(ap);
1621         }
1622         return NULL;
1623 }
1624
1625 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1626 {
1627         if (!branch)
1628                 return error_buf(err, _("HEAD does not point to a branch"));
1629
1630         if (!branch->merge || !branch->merge[0]) {
1631                 /*
1632                  * no merge config; is it because the user didn't define any,
1633                  * or because it is not a real branch, and get_branch
1634                  * auto-vivified it?
1635                  */
1636                 if (!ref_exists(branch->refname))
1637                         return error_buf(err, _("no such branch: '%s'"),
1638                                          branch->name);
1639                 return error_buf(err,
1640                                  _("no upstream configured for branch '%s'"),
1641                                  branch->name);
1642         }
1643
1644         if (!branch->merge[0]->dst)
1645                 return error_buf(err,
1646                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1647                                  branch->merge[0]->src);
1648
1649         return branch->merge[0]->dst;
1650 }
1651
1652 static const char *tracking_for_push_dest(struct remote *remote,
1653                                           const char *refname,
1654                                           struct strbuf *err)
1655 {
1656         char *ret;
1657
1658         ret = apply_refspecs(&remote->fetch, refname);
1659         if (!ret)
1660                 return error_buf(err,
1661                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1662                                  refname, remote->name);
1663         return ret;
1664 }
1665
1666 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1667 {
1668         struct remote *remote;
1669
1670         remote = remote_get(pushremote_for_branch(branch, NULL));
1671         if (!remote)
1672                 return error_buf(err,
1673                                  _("branch '%s' has no remote for pushing"),
1674                                  branch->name);
1675
1676         if (remote->push.nr) {
1677                 char *dst;
1678                 const char *ret;
1679
1680                 dst = apply_refspecs(&remote->push, branch->refname);
1681                 if (!dst)
1682                         return error_buf(err,
1683                                          _("push refspecs for '%s' do not include '%s'"),
1684                                          remote->name, branch->name);
1685
1686                 ret = tracking_for_push_dest(remote, dst, err);
1687                 free(dst);
1688                 return ret;
1689         }
1690
1691         if (remote->mirror)
1692                 return tracking_for_push_dest(remote, branch->refname, err);
1693
1694         switch (push_default) {
1695         case PUSH_DEFAULT_NOTHING:
1696                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1697
1698         case PUSH_DEFAULT_MATCHING:
1699         case PUSH_DEFAULT_CURRENT:
1700                 return tracking_for_push_dest(remote, branch->refname, err);
1701
1702         case PUSH_DEFAULT_UPSTREAM:
1703                 return branch_get_upstream(branch, err);
1704
1705         case PUSH_DEFAULT_UNSPECIFIED:
1706         case PUSH_DEFAULT_SIMPLE:
1707                 {
1708                         const char *up, *cur;
1709
1710                         up = branch_get_upstream(branch, err);
1711                         if (!up)
1712                                 return NULL;
1713                         cur = tracking_for_push_dest(remote, branch->refname, err);
1714                         if (!cur)
1715                                 return NULL;
1716                         if (strcmp(cur, up))
1717                                 return error_buf(err,
1718                                                  _("cannot resolve 'simple' push to a single destination"));
1719                         return cur;
1720                 }
1721         }
1722
1723         BUG("unhandled push situation");
1724 }
1725
1726 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1727 {
1728         if (!branch)
1729                 return error_buf(err, _("HEAD does not point to a branch"));
1730
1731         if (!branch->push_tracking_ref)
1732                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1733         return branch->push_tracking_ref;
1734 }
1735
1736 static int ignore_symref_update(const char *refname)
1737 {
1738         int flag;
1739
1740         if (!resolve_ref_unsafe(refname, 0, NULL, &flag))
1741                 return 0; /* non-existing refs are OK */
1742         return (flag & REF_ISSYMREF);
1743 }
1744
1745 /*
1746  * Create and return a list of (struct ref) consisting of copies of
1747  * each remote_ref that matches refspec.  refspec must be a pattern.
1748  * Fill in the copies' peer_ref to describe the local tracking refs to
1749  * which they map.  Omit any references that would map to an existing
1750  * local symbolic ref.
1751  */
1752 static struct ref *get_expanded_map(const struct ref *remote_refs,
1753                                     const struct refspec_item *refspec)
1754 {
1755         const struct ref *ref;
1756         struct ref *ret = NULL;
1757         struct ref **tail = &ret;
1758
1759         for (ref = remote_refs; ref; ref = ref->next) {
1760                 char *expn_name = NULL;
1761
1762                 if (strchr(ref->name, '^'))
1763                         continue; /* a dereference item */
1764                 if (match_name_with_pattern(refspec->src, ref->name,
1765                                             refspec->dst, &expn_name) &&
1766                     !ignore_symref_update(expn_name)) {
1767                         struct ref *cpy = copy_ref(ref);
1768
1769                         cpy->peer_ref = alloc_ref(expn_name);
1770                         if (refspec->force)
1771                                 cpy->peer_ref->force = 1;
1772                         *tail = cpy;
1773                         tail = &cpy->next;
1774                 }
1775                 free(expn_name);
1776         }
1777
1778         return ret;
1779 }
1780
1781 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1782 {
1783         const struct ref *ref;
1784         const struct ref *best_match = NULL;
1785         int best_score = 0;
1786
1787         for (ref = refs; ref; ref = ref->next) {
1788                 int score = refname_match(name, ref->name);
1789
1790                 if (best_score < score) {
1791                         best_match = ref;
1792                         best_score = score;
1793                 }
1794         }
1795         return best_match;
1796 }
1797
1798 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1799 {
1800         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1801
1802         if (!ref)
1803                 return NULL;
1804
1805         return copy_ref(ref);
1806 }
1807
1808 static struct ref *get_local_ref(const char *name)
1809 {
1810         if (!name || name[0] == '\0')
1811                 return NULL;
1812
1813         if (starts_with(name, "refs/"))
1814                 return alloc_ref(name);
1815
1816         if (starts_with(name, "heads/") ||
1817             starts_with(name, "tags/") ||
1818             starts_with(name, "remotes/"))
1819                 return alloc_ref_with_prefix("refs/", 5, name);
1820
1821         return alloc_ref_with_prefix("refs/heads/", 11, name);
1822 }
1823
1824 int get_fetch_map(const struct ref *remote_refs,
1825                   const struct refspec_item *refspec,
1826                   struct ref ***tail,
1827                   int missing_ok)
1828 {
1829         struct ref *ref_map, **rmp;
1830
1831         if (refspec->pattern) {
1832                 ref_map = get_expanded_map(remote_refs, refspec);
1833         } else {
1834                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1835
1836                 if (refspec->exact_sha1) {
1837                         ref_map = alloc_ref(name);
1838                         get_oid_hex(name, &ref_map->old_oid);
1839                         ref_map->exact_oid = 1;
1840                 } else {
1841                         ref_map = get_remote_ref(remote_refs, name);
1842                 }
1843                 if (!missing_ok && !ref_map)
1844                         die(_("couldn't find remote ref %s"), name);
1845                 if (ref_map) {
1846                         ref_map->peer_ref = get_local_ref(refspec->dst);
1847                         if (ref_map->peer_ref && refspec->force)
1848                                 ref_map->peer_ref->force = 1;
1849                 }
1850         }
1851
1852         for (rmp = &ref_map; *rmp; ) {
1853                 if ((*rmp)->peer_ref) {
1854                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1855                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1856                                 struct ref *ignore = *rmp;
1857                                 error(_("* Ignoring funny ref '%s' locally"),
1858                                       (*rmp)->peer_ref->name);
1859                                 *rmp = (*rmp)->next;
1860                                 free(ignore->peer_ref);
1861                                 free(ignore);
1862                                 continue;
1863                         }
1864                 }
1865                 rmp = &((*rmp)->next);
1866         }
1867
1868         if (ref_map)
1869                 tail_link_ref(ref_map, tail);
1870
1871         return 0;
1872 }
1873
1874 int resolve_remote_symref(struct ref *ref, struct ref *list)
1875 {
1876         if (!ref->symref)
1877                 return 0;
1878         for (; list; list = list->next)
1879                 if (!strcmp(ref->symref, list->name)) {
1880                         oidcpy(&ref->old_oid, &list->old_oid);
1881                         return 0;
1882                 }
1883         return 1;
1884 }
1885
1886 /*
1887  * Compute the commit ahead/behind values for the pair branch_name, base.
1888  *
1889  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1890  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1891  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1892  * set to zero).
1893  *
1894  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., ref
1895  * does not exist).  Returns 0 if the commits are identical.  Returns 1 if
1896  * commits are different.
1897  */
1898
1899 static int stat_branch_pair(const char *branch_name, const char *base,
1900                              int *num_ours, int *num_theirs,
1901                              enum ahead_behind_flags abf)
1902 {
1903         struct object_id oid;
1904         struct commit *ours, *theirs;
1905         struct rev_info revs;
1906         struct argv_array argv = ARGV_ARRAY_INIT;
1907
1908         /* Cannot stat if what we used to build on no longer exists */
1909         if (read_ref(base, &oid))
1910                 return -1;
1911         theirs = lookup_commit_reference(the_repository, &oid);
1912         if (!theirs)
1913                 return -1;
1914
1915         if (read_ref(branch_name, &oid))
1916                 return -1;
1917         ours = lookup_commit_reference(the_repository, &oid);
1918         if (!ours)
1919                 return -1;
1920
1921         *num_theirs = *num_ours = 0;
1922
1923         /* are we the same? */
1924         if (theirs == ours)
1925                 return 0;
1926         if (abf == AHEAD_BEHIND_QUICK)
1927                 return 1;
1928         if (abf != AHEAD_BEHIND_FULL)
1929                 BUG("stat_branch_pair: invalid abf '%d'", abf);
1930
1931         /* Run "rev-list --left-right ours...theirs" internally... */
1932         argv_array_push(&argv, ""); /* ignored */
1933         argv_array_push(&argv, "--left-right");
1934         argv_array_pushf(&argv, "%s...%s",
1935                          oid_to_hex(&ours->object.oid),
1936                          oid_to_hex(&theirs->object.oid));
1937         argv_array_push(&argv, "--");
1938
1939         repo_init_revisions(the_repository, &revs, NULL);
1940         setup_revisions(argv.argc, argv.argv, &revs, NULL);
1941         if (prepare_revision_walk(&revs))
1942                 die(_("revision walk setup failed"));
1943
1944         /* ... and count the commits on each side. */
1945         while (1) {
1946                 struct commit *c = get_revision(&revs);
1947                 if (!c)
1948                         break;
1949                 if (c->object.flags & SYMMETRIC_LEFT)
1950                         (*num_ours)++;
1951                 else
1952                         (*num_theirs)++;
1953         }
1954
1955         /* clear object flags smudged by the above traversal */
1956         clear_commit_marks(ours, ALL_REV_FLAGS);
1957         clear_commit_marks(theirs, ALL_REV_FLAGS);
1958
1959         argv_array_clear(&argv);
1960         return 1;
1961 }
1962
1963 /*
1964  * Lookup the tracking branch for the given branch and if present, optionally
1965  * compute the commit ahead/behind values for the pair.
1966  *
1967  * If for_push is true, the tracking branch refers to the push branch,
1968  * otherwise it refers to the upstream branch.
1969  *
1970  * The name of the tracking branch (or NULL if it is not defined) is
1971  * returned via *tracking_name, if it is not itself NULL.
1972  *
1973  * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
1974  * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
1975  * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
1976  * set to zero).
1977  *
1978  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1979  * upstream defined, or ref does not exist).  Returns 0 if the commits are
1980  * identical.  Returns 1 if commits are different.
1981  */
1982 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1983                        const char **tracking_name, int for_push,
1984                        enum ahead_behind_flags abf)
1985 {
1986         const char *base;
1987
1988         /* Cannot stat unless we are marked to build on top of somebody else. */
1989         base = for_push ? branch_get_push(branch, NULL) :
1990                 branch_get_upstream(branch, NULL);
1991         if (tracking_name)
1992                 *tracking_name = base;
1993         if (!base)
1994                 return -1;
1995
1996         return stat_branch_pair(branch->refname, base, num_ours, num_theirs, abf);
1997 }
1998
1999 /*
2000  * Return true when there is anything to report, otherwise false.
2001  */
2002 int format_tracking_info(struct branch *branch, struct strbuf *sb,
2003                          enum ahead_behind_flags abf)
2004 {
2005         int ours, theirs, sti;
2006         const char *full_base;
2007         char *base;
2008         int upstream_is_gone = 0;
2009
2010         sti = stat_tracking_info(branch, &ours, &theirs, &full_base, 0, abf);
2011         if (sti < 0) {
2012                 if (!full_base)
2013                         return 0;
2014                 upstream_is_gone = 1;
2015         }
2016
2017         base = shorten_unambiguous_ref(full_base, 0);
2018         if (upstream_is_gone) {
2019                 strbuf_addf(sb,
2020                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2021                         base);
2022                 if (advice_status_hints)
2023                         strbuf_addstr(sb,
2024                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2025         } else if (!sti) {
2026                 strbuf_addf(sb,
2027                         _("Your branch is up to date with '%s'.\n"),
2028                         base);
2029         } else if (abf == AHEAD_BEHIND_QUICK) {
2030                 strbuf_addf(sb,
2031                             _("Your branch and '%s' refer to different commits.\n"),
2032                             base);
2033                 if (advice_status_hints)
2034                         strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
2035                                     "git status --ahead-behind");
2036         } else if (!theirs) {
2037                 strbuf_addf(sb,
2038                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2039                            "Your branch is ahead of '%s' by %d commits.\n",
2040                            ours),
2041                         base, ours);
2042                 if (advice_status_hints)
2043                         strbuf_addstr(sb,
2044                                 _("  (use \"git push\" to publish your local commits)\n"));
2045         } else if (!ours) {
2046                 strbuf_addf(sb,
2047                         Q_("Your branch is behind '%s' by %d commit, "
2048                                "and can be fast-forwarded.\n",
2049                            "Your branch is behind '%s' by %d commits, "
2050                                "and can be fast-forwarded.\n",
2051                            theirs),
2052                         base, theirs);
2053                 if (advice_status_hints)
2054                         strbuf_addstr(sb,
2055                                 _("  (use \"git pull\" to update your local branch)\n"));
2056         } else {
2057                 strbuf_addf(sb,
2058                         Q_("Your branch and '%s' have diverged,\n"
2059                                "and have %d and %d different commit each, "
2060                                "respectively.\n",
2061                            "Your branch and '%s' have diverged,\n"
2062                                "and have %d and %d different commits each, "
2063                                "respectively.\n",
2064                            ours + theirs),
2065                         base, ours, theirs);
2066                 if (advice_status_hints)
2067                         strbuf_addstr(sb,
2068                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2069         }
2070         free(base);
2071         return 1;
2072 }
2073
2074 static int one_local_ref(const char *refname, const struct object_id *oid,
2075                          int flag, void *cb_data)
2076 {
2077         struct ref ***local_tail = cb_data;
2078         struct ref *ref;
2079
2080         /* we already know it starts with refs/ to get here */
2081         if (check_refname_format(refname + 5, 0))
2082                 return 0;
2083
2084         ref = alloc_ref(refname);
2085         oidcpy(&ref->new_oid, oid);
2086         **local_tail = ref;
2087         *local_tail = &ref->next;
2088         return 0;
2089 }
2090
2091 struct ref *get_local_heads(void)
2092 {
2093         struct ref *local_refs = NULL, **local_tail = &local_refs;
2094
2095         for_each_ref(one_local_ref, &local_tail);
2096         return local_refs;
2097 }
2098
2099 struct ref *guess_remote_head(const struct ref *head,
2100                               const struct ref *refs,
2101                               int all)
2102 {
2103         const struct ref *r;
2104         struct ref *list = NULL;
2105         struct ref **tail = &list;
2106
2107         if (!head)
2108                 return NULL;
2109
2110         /*
2111          * Some transports support directly peeking at
2112          * where HEAD points; if that is the case, then
2113          * we don't have to guess.
2114          */
2115         if (head->symref)
2116                 return copy_ref(find_ref_by_name(refs, head->symref));
2117
2118         /* If refs/heads/master could be right, it is. */
2119         if (!all) {
2120                 r = find_ref_by_name(refs, "refs/heads/master");
2121                 if (r && oideq(&r->old_oid, &head->old_oid))
2122                         return copy_ref(r);
2123         }
2124
2125         /* Look for another ref that points there */
2126         for (r = refs; r; r = r->next) {
2127                 if (r != head &&
2128                     starts_with(r->name, "refs/heads/") &&
2129                     oideq(&r->old_oid, &head->old_oid)) {
2130                         *tail = copy_ref(r);
2131                         tail = &((*tail)->next);
2132                         if (!all)
2133                                 break;
2134                 }
2135         }
2136
2137         return list;
2138 }
2139
2140 struct stale_heads_info {
2141         struct string_list *ref_names;
2142         struct ref **stale_refs_tail;
2143         struct refspec *rs;
2144 };
2145
2146 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2147                               int flags, void *cb_data)
2148 {
2149         struct stale_heads_info *info = cb_data;
2150         struct string_list matches = STRING_LIST_INIT_DUP;
2151         struct refspec_item query;
2152         int i, stale = 1;
2153         memset(&query, 0, sizeof(struct refspec_item));
2154         query.dst = (char *)refname;
2155
2156         query_refspecs_multiple(info->rs, &query, &matches);
2157         if (matches.nr == 0)
2158                 goto clean_exit; /* No matches */
2159
2160         /*
2161          * If we did find a suitable refspec and it's not a symref and
2162          * it's not in the list of refs that currently exist in that
2163          * remote, we consider it to be stale. In order to deal with
2164          * overlapping refspecs, we need to go over all of the
2165          * matching refs.
2166          */
2167         if (flags & REF_ISSYMREF)
2168                 goto clean_exit;
2169
2170         for (i = 0; stale && i < matches.nr; i++)
2171                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2172                         stale = 0;
2173
2174         if (stale) {
2175                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2176                 oidcpy(&ref->new_oid, oid);
2177         }
2178
2179 clean_exit:
2180         string_list_clear(&matches, 0);
2181         return 0;
2182 }
2183
2184 struct ref *get_stale_heads(struct refspec *rs, struct ref *fetch_map)
2185 {
2186         struct ref *ref, *stale_refs = NULL;
2187         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2188         struct stale_heads_info info;
2189
2190         info.ref_names = &ref_names;
2191         info.stale_refs_tail = &stale_refs;
2192         info.rs = rs;
2193         for (ref = fetch_map; ref; ref = ref->next)
2194                 string_list_append(&ref_names, ref->name);
2195         string_list_sort(&ref_names);
2196         for_each_ref(get_stale_heads_cb, &info);
2197         string_list_clear(&ref_names, 0);
2198         return stale_refs;
2199 }
2200
2201 /*
2202  * Compare-and-swap
2203  */
2204 static void clear_cas_option(struct push_cas_option *cas)
2205 {
2206         int i;
2207
2208         for (i = 0; i < cas->nr; i++)
2209                 free(cas->entry[i].refname);
2210         free(cas->entry);
2211         memset(cas, 0, sizeof(*cas));
2212 }
2213
2214 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2215                                       const char *refname,
2216                                       size_t refnamelen)
2217 {
2218         struct push_cas *entry;
2219         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2220         entry = &cas->entry[cas->nr++];
2221         memset(entry, 0, sizeof(*entry));
2222         entry->refname = xmemdupz(refname, refnamelen);
2223         return entry;
2224 }
2225
2226 static int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2227 {
2228         const char *colon;
2229         struct push_cas *entry;
2230
2231         if (unset) {
2232                 /* "--no-<option>" */
2233                 clear_cas_option(cas);
2234                 return 0;
2235         }
2236
2237         if (!arg) {
2238                 /* just "--<option>" */
2239                 cas->use_tracking_for_rest = 1;
2240                 return 0;
2241         }
2242
2243         /* "--<option>=refname" or "--<option>=refname:value" */
2244         colon = strchrnul(arg, ':');
2245         entry = add_cas_entry(cas, arg, colon - arg);
2246         if (!*colon)
2247                 entry->use_tracking = 1;
2248         else if (!colon[1])
2249                 oidclr(&entry->expect);
2250         else if (get_oid(colon + 1, &entry->expect))
2251                 return error(_("cannot parse expected object name '%s'"),
2252                              colon + 1);
2253         return 0;
2254 }
2255
2256 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2257 {
2258         return parse_push_cas_option(opt->value, arg, unset);
2259 }
2260
2261 int is_empty_cas(const struct push_cas_option *cas)
2262 {
2263         return !cas->use_tracking_for_rest && !cas->nr;
2264 }
2265
2266 /*
2267  * Look at remote.fetch refspec and see if we have a remote
2268  * tracking branch for the refname there.  Fill its current
2269  * value in sha1[].
2270  * If we cannot do so, return negative to signal an error.
2271  */
2272 static int remote_tracking(struct remote *remote, const char *refname,
2273                            struct object_id *oid)
2274 {
2275         char *dst;
2276
2277         dst = apply_refspecs(&remote->fetch, refname);
2278         if (!dst)
2279                 return -1; /* no tracking ref for refname at remote */
2280         if (read_ref(dst, oid))
2281                 return -1; /* we know what the tracking ref is but we cannot read it */
2282         return 0;
2283 }
2284
2285 static void apply_cas(struct push_cas_option *cas,
2286                       struct remote *remote,
2287                       struct ref *ref)
2288 {
2289         int i;
2290
2291         /* Find an explicit --<option>=<name>[:<value>] entry */
2292         for (i = 0; i < cas->nr; i++) {
2293                 struct push_cas *entry = &cas->entry[i];
2294                 if (!refname_match(entry->refname, ref->name))
2295                         continue;
2296                 ref->expect_old_sha1 = 1;
2297                 if (!entry->use_tracking)
2298                         oidcpy(&ref->old_oid_expect, &entry->expect);
2299                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2300                         oidclr(&ref->old_oid_expect);
2301                 return;
2302         }
2303
2304         /* Are we using "--<option>" to cover all? */
2305         if (!cas->use_tracking_for_rest)
2306                 return;
2307
2308         ref->expect_old_sha1 = 1;
2309         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2310                 oidclr(&ref->old_oid_expect);
2311 }
2312
2313 void apply_push_cas(struct push_cas_option *cas,
2314                     struct remote *remote,
2315                     struct ref *remote_refs)
2316 {
2317         struct ref *ref;
2318         for (ref = remote_refs; ref; ref = ref->next)
2319                 apply_cas(cas, remote, ref);
2320 }