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