git.oblomov.eu Git - git/blob - remote.c

   1 #include "cache.h"
   2 #include "remote.h"
   3 #include "refs.h"
   4 #include "commit.h"
   5 #include "diff.h"
   6 #include "revision.h"
   7 #include "dir.h"
   8 #include "tag.h"
   9 #include "string-list.h"
  10 #include "mergesort.h"
  11 #include "argv-array.h"
  12
  13 enum map_direction { FROM_SRC, FROM_DST };
  14
  15 static struct refspec s_tag_refspec = {
  16         0,
  17         1,
  18         0,
  19         0,
  20         "refs/tags/*",
  21         "refs/tags/*"
  22 };
  23
  24 const struct refspec *tag_refspec = &s_tag_refspec;
  25
  26 struct counted_string {
  27         size_t len;
  28         const char *s;
  29 };
  30 struct rewrite {
  31         const char *base;
  32         size_t baselen;
  33         struct counted_string *instead_of;
  34         int instead_of_nr;
  35         int instead_of_alloc;
  36 };
  37 struct rewrites {
  38         struct rewrite **rewrite;
  39         int rewrite_alloc;
  40         int rewrite_nr;
  41 };
  42
  43 static struct remote **remotes;
  44 static int remotes_alloc;
  45 static int remotes_nr;
  46 static struct hashmap remotes_hash;
  47
  48 static struct branch **branches;
  49 static int branches_alloc;
  50 static int branches_nr;
  51
  52 static struct branch *current_branch;
  53 static const char *pushremote_name;
  54
  55 static struct rewrites rewrites;
  56 static struct rewrites rewrites_push;
  57
  58 static int valid_remote(const struct remote *remote)
  59 {
  60         return (!!remote->url) || (!!remote->foreign_vcs);
  61 }
  62
  63 static const char *alias_url(const char *url, struct rewrites *r)
  64 {
  65         int i, j;
  66         struct counted_string *longest;
  67         int longest_i;
  68
  69         longest = NULL;
  70         longest_i = -1;
  71         for (i = 0; i < r->rewrite_nr; i++) {
  72                 if (!r->rewrite[i])
  73                         continue;
  74                 for (j = 0; j < r->rewrite[i]->instead_of_nr; j++) {
  75                         if (starts_with(url, r->rewrite[i]->instead_of[j].s) &&
  76                             (!longest ||
  77                              longest->len < r->rewrite[i]->instead_of[j].len)) {
  78                                 longest = &(r->rewrite[i]->instead_of[j]);
  79                                 longest_i = i;
  80                         }
  81                 }
  82         }
  83         if (!longest)
  84                 return url;
  85
  86         return xstrfmt("%s%s", r->rewrite[longest_i]->base, url + longest->len);
  87 }
  88
  89 static void add_push_refspec(struct remote *remote, const char *ref)
  90 {
  91         ALLOC_GROW(remote->push_refspec,
  92                    remote->push_refspec_nr + 1,
  93                    remote->push_refspec_alloc);
  94         remote->push_refspec[remote->push_refspec_nr++] = ref;
  95 }
  96
  97 static void add_fetch_refspec(struct remote *remote, const char *ref)
  98 {
  99         ALLOC_GROW(remote->fetch_refspec,
 100                    remote->fetch_refspec_nr + 1,
 101                    remote->fetch_refspec_alloc);
 102         remote->fetch_refspec[remote->fetch_refspec_nr++] = ref;
 103 }
 104
 105 static void add_url(struct remote *remote, const char *url)
 106 {
 107         ALLOC_GROW(remote->url, remote->url_nr + 1, remote->url_alloc);
 108         remote->url[remote->url_nr++] = url;
 109 }
 110
 111 static void add_pushurl(struct remote *remote, const char *pushurl)
 112 {
 113         ALLOC_GROW(remote->pushurl, remote->pushurl_nr + 1, remote->pushurl_alloc);
 114         remote->pushurl[remote->pushurl_nr++] = pushurl;
 115 }
 116
 117 static void add_pushurl_alias(struct remote *remote, const char *url)
 118 {
 119         const char *pushurl = alias_url(url, &rewrites_push);
 120         if (pushurl != url)
 121                 add_pushurl(remote, pushurl);
 122 }
 123
 124 static void add_url_alias(struct remote *remote, const char *url)
 125 {
 126         add_url(remote, alias_url(url, &rewrites));
 127         add_pushurl_alias(remote, url);
 128 }
 129
 130 struct remotes_hash_key {
 131         const char *str;
 132         int len;
 133 };
 134
 135 static int remotes_hash_cmp(const struct remote *a, const struct remote *b, const struct remotes_hash_key *key)
 136 {
 137         if (key)
 138                 return strncmp(a->name, key->str, key->len) || a->name[key->len];
 139         else
 140                 return strcmp(a->name, b->name);
 141 }
 142
 143 static inline void init_remotes_hash(void)
 144 {
 145         if (!remotes_hash.cmpfn)
 146                 hashmap_init(&remotes_hash, (hashmap_cmp_fn)remotes_hash_cmp, 0);
 147 }
 148
 149 static struct remote *make_remote(const char *name, int len)
 150 {
 151         struct remote *ret, *replaced;
 152         struct remotes_hash_key lookup;
 153         struct hashmap_entry lookup_entry;
 154
 155         if (!len)
 156                 len = strlen(name);
 157
 158         init_remotes_hash();
 159         lookup.str = name;
 160         lookup.len = len;
 161         hashmap_entry_init(&lookup_entry, memhash(name, len));
 162
 163         if ((ret = hashmap_get(&remotes_hash, &lookup_entry, &lookup)) != NULL)
 164                 return ret;
 165
 166         ret = xcalloc(1, sizeof(struct remote));
 167         ret->prune = -1;  /* unspecified */
 168         ALLOC_GROW(remotes, remotes_nr + 1, remotes_alloc);
 169         remotes[remotes_nr++] = ret;
 170         ret->name = xstrndup(name, len);
 171
 172         hashmap_entry_init(ret, lookup_entry.hash);
 173         replaced = hashmap_put(&remotes_hash, ret);
 174         assert(replaced == NULL);  /* no previous entry overwritten */
 175         return ret;
 176 }
 177
 178 static void add_merge(struct branch *branch, const char *name)
 179 {
 180         ALLOC_GROW(branch->merge_name, branch->merge_nr + 1,
 181                    branch->merge_alloc);
 182         branch->merge_name[branch->merge_nr++] = name;
 183 }
 184
 185 static struct branch *make_branch(const char *name, int len)
 186 {
 187         struct branch *ret;
 188         int i;
 189
 190         for (i = 0; i < branches_nr; i++) {
 191                 if (len ? (!strncmp(name, branches[i]->name, len) &&
 192                            !branches[i]->name[len]) :
 193                     !strcmp(name, branches[i]->name))
 194                         return branches[i];
 195         }
 196
 197         ALLOC_GROW(branches, branches_nr + 1, branches_alloc);
 198         ret = xcalloc(1, sizeof(struct branch));
 199         branches[branches_nr++] = ret;
 200         if (len)
 201                 ret->name = xstrndup(name, len);
 202         else
 203                 ret->name = xstrdup(name);
 204         ret->refname = xstrfmt("refs/heads/%s", ret->name);
 205
 206         return ret;
 207 }
 208
 209 static struct rewrite *make_rewrite(struct rewrites *r, const char *base, int len)
 210 {
 211         struct rewrite *ret;
 212         int i;
 213
 214         for (i = 0; i < r->rewrite_nr; i++) {
 215                 if (len
 216                     ? (len == r->rewrite[i]->baselen &&
 217                        !strncmp(base, r->rewrite[i]->base, len))
 218                     : !strcmp(base, r->rewrite[i]->base))
 219                         return r->rewrite[i];
 220         }
 221
 222         ALLOC_GROW(r->rewrite, r->rewrite_nr + 1, r->rewrite_alloc);
 223         ret = xcalloc(1, sizeof(struct rewrite));
 224         r->rewrite[r->rewrite_nr++] = ret;
 225         if (len) {
 226                 ret->base = xstrndup(base, len);
 227                 ret->baselen = len;
 228         }
 229         else {
 230                 ret->base = xstrdup(base);
 231                 ret->baselen = strlen(base);
 232         }
 233         return ret;
 234 }
 235
 236 static void add_instead_of(struct rewrite *rewrite, const char *instead_of)
 237 {
 238         ALLOC_GROW(rewrite->instead_of, rewrite->instead_of_nr + 1, rewrite->instead_of_alloc);
 239         rewrite->instead_of[rewrite->instead_of_nr].s = instead_of;
 240         rewrite->instead_of[rewrite->instead_of_nr].len = strlen(instead_of);
 241         rewrite->instead_of_nr++;
 242 }
 243
 244 static const char *skip_spaces(const char *s)
 245 {
 246         while (isspace(*s))
 247                 s++;
 248         return s;
 249 }
 250
 251 static void read_remotes_file(struct remote *remote)
 252 {
 253         struct strbuf buf = STRBUF_INIT;
 254         FILE *f = fopen(git_path("remotes/%s", remote->name), "r");
 255
 256         if (!f)
 257                 return;
 258         remote->origin = REMOTE_REMOTES;
 259         while (strbuf_getline(&buf, f, '\n') != EOF) {
 260                 const char *v;
 261
 262                 strbuf_rtrim(&buf);
 263
 264                 if (skip_prefix(buf.buf, "URL:", &v))
 265                         add_url_alias(remote, xstrdup(skip_spaces(v)));
 266                 else if (skip_prefix(buf.buf, "Push:", &v))
 267                         add_push_refspec(remote, xstrdup(skip_spaces(v)));
 268                 else if (skip_prefix(buf.buf, "Pull:", &v))
 269                         add_fetch_refspec(remote, xstrdup(skip_spaces(v)));
 270         }
 271         strbuf_release(&buf);
 272         fclose(f);
 273 }
 274
 275 static void read_branches_file(struct remote *remote)
 276 {
 277         char *frag;
 278         struct strbuf buf = STRBUF_INIT;
 279         FILE *f = fopen(git_path("branches/%s", remote->name), "r");
 280
 281         if (!f)
 282                 return;
 283
 284         strbuf_getline(&buf, f, '\n');
 285         fclose(f);
 286         strbuf_trim(&buf);
 287         if (!buf.len) {
 288                 strbuf_release(&buf);
 289                 return;
 290         }
 291
 292         remote->origin = REMOTE_BRANCHES;
 293
 294         /*
 295          * The branches file would have URL and optionally
 296          * #branch specified.  The "master" (or specified) branch is
 297          * fetched and stored in the local branch matching the
 298          * remote name.
 299          */
 300         frag = strchr(buf.buf, '#');
 301         if (frag)
 302                 *(frag++) = '\0';
 303         else
 304                 frag = "master";
 305
 306         add_url_alias(remote, strbuf_detach(&buf, NULL));
 307         add_fetch_refspec(remote, xstrfmt("refs/heads/%s:refs/heads/%s",
 308                                           frag, remote->name));
 309
 310         /*
 311          * Cogito compatible push: push current HEAD to remote #branch
 312          * (master if missing)
 313          */
 314         add_push_refspec(remote, xstrfmt("HEAD:refs/heads/%s", frag));
 315         remote->fetch_tags = 1; /* always auto-follow */
 316 }
 317
 318 static int handle_config(const char *key, const char *value, void *cb)
 319 {
 320         const char *name;
 321         const char *subkey;
 322         struct remote *remote;
 323         struct branch *branch;
 324         if (starts_with(key, "branch.")) {
 325                 name = key + 7;
 326                 subkey = strrchr(name, '.');
 327                 if (!subkey)
 328                         return 0;
 329                 branch = make_branch(name, subkey - name);
 330                 if (!strcmp(subkey, ".remote")) {
 331                         return git_config_string(&branch->remote_name, key, value);
 332                 } else if (!strcmp(subkey, ".pushremote")) {
 333                         return git_config_string(&branch->pushremote_name, key, value);
 334                 } else if (!strcmp(subkey, ".merge")) {
 335                         if (!value)
 336                                 return config_error_nonbool(key);
 337                         add_merge(branch, xstrdup(value));
 338                 }
 339                 return 0;
 340         }
 341         if (starts_with(key, "url.")) {
 342                 struct rewrite *rewrite;
 343                 name = key + 4;
 344                 subkey = strrchr(name, '.');
 345                 if (!subkey)
 346                         return 0;
 347                 if (!strcmp(subkey, ".insteadof")) {
 348                         rewrite = make_rewrite(&rewrites, name, subkey - name);
 349                         if (!value)
 350                                 return config_error_nonbool(key);
 351                         add_instead_of(rewrite, xstrdup(value));
 352                 } else if (!strcmp(subkey, ".pushinsteadof")) {
 353                         rewrite = make_rewrite(&rewrites_push, name, subkey - name);
 354                         if (!value)
 355                                 return config_error_nonbool(key);
 356                         add_instead_of(rewrite, xstrdup(value));
 357                 }
 358         }
 359
 360         if (!starts_with(key,  "remote."))
 361                 return 0;
 362         name = key + 7;
 363
 364         /* Handle remote.* variables */
 365         if (!strcmp(name, "pushdefault"))
 366                 return git_config_string(&pushremote_name, key, value);
 367
 368         /* Handle remote.<name>.* variables */
 369         if (*name == '/') {
 370                 warning("Config remote shorthand cannot begin with '/': %s",
 371                         name);
 372                 return 0;
 373         }
 374         subkey = strrchr(name, '.');
 375         if (!subkey)
 376                 return 0;
 377         remote = make_remote(name, subkey - name);
 378         remote->origin = REMOTE_CONFIG;
 379         if (!strcmp(subkey, ".mirror"))
 380                 remote->mirror = git_config_bool(key, value);
 381         else if (!strcmp(subkey, ".skipdefaultupdate"))
 382                 remote->skip_default_update = git_config_bool(key, value);
 383         else if (!strcmp(subkey, ".skipfetchall"))
 384                 remote->skip_default_update = git_config_bool(key, value);
 385         else if (!strcmp(subkey, ".prune"))
 386                 remote->prune = git_config_bool(key, value);
 387         else if (!strcmp(subkey, ".url")) {
 388                 const char *v;
 389                 if (git_config_string(&v, key, value))
 390                         return -1;
 391                 add_url(remote, v);
 392         } else if (!strcmp(subkey, ".pushurl")) {
 393                 const char *v;
 394                 if (git_config_string(&v, key, value))
 395                         return -1;
 396                 add_pushurl(remote, v);
 397         } else if (!strcmp(subkey, ".push")) {
 398                 const char *v;
 399                 if (git_config_string(&v, key, value))
 400                         return -1;
 401                 add_push_refspec(remote, v);
 402         } else if (!strcmp(subkey, ".fetch")) {
 403                 const char *v;
 404                 if (git_config_string(&v, key, value))
 405                         return -1;
 406                 add_fetch_refspec(remote, 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, ".vcs")) {
 432                 return git_config_string(&remote->foreign_vcs, key, value);
 433         }
 434         return 0;
 435 }
 436
 437 static void alias_all_urls(void)
 438 {
 439         int i, j;
 440         for (i = 0; i < remotes_nr; i++) {
 441                 int add_pushurl_aliases;
 442                 if (!remotes[i])
 443                         continue;
 444                 for (j = 0; j < remotes[i]->pushurl_nr; j++) {
 445                         remotes[i]->pushurl[j] = alias_url(remotes[i]->pushurl[j], &rewrites);
 446                 }
 447                 add_pushurl_aliases = remotes[i]->pushurl_nr == 0;
 448                 for (j = 0; j < remotes[i]->url_nr; j++) {
 449                         if (add_pushurl_aliases)
 450                                 add_pushurl_alias(remotes[i], remotes[i]->url[j]);
 451                         remotes[i]->url[j] = alias_url(remotes[i]->url[j], &rewrites);
 452                 }
 453         }
 454 }
 455
 456 static void read_config(void)
 457 {
 458         static int loaded;
 459         struct object_id oid;
 460         const char *head_ref;
 461         int flag;
 462
 463         if (loaded)
 464                 return;
 465         loaded = 1;
 466
 467         current_branch = NULL;
 468         head_ref = resolve_ref_unsafe("HEAD", 0, oid.hash, &flag);
 469         if (head_ref && (flag & REF_ISSYMREF) &&
 470             skip_prefix(head_ref, "refs/heads/", &head_ref)) {
 471                 current_branch = make_branch(head_ref, 0);
 472         }
 473         git_config(handle_config, NULL);
 474         alias_all_urls();
 475 }
 476
 477 /*
 478  * This function frees a refspec array.
 479  * Warning: code paths should be checked to ensure that the src
 480  *          and dst pointers are always freeable pointers as well
 481  *          as the refspec pointer itself.
 482  */
 483 static void free_refspecs(struct refspec *refspec, int nr_refspec)
 484 {
 485         int i;
 486
 487         if (!refspec)
 488                 return;
 489
 490         for (i = 0; i < nr_refspec; i++) {
 491                 free(refspec[i].src);
 492                 free(refspec[i].dst);
 493         }
 494         free(refspec);
 495 }
 496
 497 static struct refspec *parse_refspec_internal(int nr_refspec, const char **refspec, int fetch, int verify)
 498 {
 499         int i;
 500         struct refspec *rs = xcalloc(nr_refspec, sizeof(*rs));
 501
 502         for (i = 0; i < nr_refspec; i++) {
 503                 size_t llen;
 504                 int is_glob;
 505                 const char *lhs, *rhs;
 506                 int flags;
 507
 508                 is_glob = 0;
 509
 510                 lhs = refspec[i];
 511                 if (*lhs == '+') {
 512                         rs[i].force = 1;
 513                         lhs++;
 514                 }
 515
 516                 rhs = strrchr(lhs, ':');
 517
 518                 /*
 519                  * Before going on, special case ":" (or "+:") as a refspec
 520                  * for pushing matching refs.
 521                  */
 522                 if (!fetch && rhs == lhs && rhs[1] == '\0') {
 523                         rs[i].matching = 1;
 524                         continue;
 525                 }
 526
 527                 if (rhs) {
 528                         size_t rlen = strlen(++rhs);
 529                         is_glob = (1 <= rlen && strchr(rhs, '*'));
 530                         rs[i].dst = xstrndup(rhs, rlen);
 531                 }
 532
 533                 llen = (rhs ? (rhs - lhs - 1) : strlen(lhs));
 534                 if (1 <= llen && memchr(lhs, '*', llen)) {
 535                         if ((rhs && !is_glob) || (!rhs && fetch))
 536                                 goto invalid;
 537                         is_glob = 1;
 538                 } else if (rhs && is_glob) {
 539                         goto invalid;
 540                 }
 541
 542                 rs[i].pattern = is_glob;
 543                 rs[i].src = xstrndup(lhs, llen);
 544                 flags = REFNAME_ALLOW_ONELEVEL | (is_glob ? REFNAME_REFSPEC_PATTERN : 0);
 545
 546                 if (fetch) {
 547                         struct object_id unused;
 548
 549                         /* LHS */
 550                         if (!*rs[i].src)
 551                                 ; /* empty is ok; it means "HEAD" */
 552                         else if (llen == GIT_SHA1_HEXSZ && !get_oid_hex(rs[i].src, &unused))
 553                                 rs[i].exact_sha1 = 1; /* ok */
 554                         else if (!check_refname_format(rs[i].src, flags))
 555                                 ; /* valid looking ref is ok */
 556                         else
 557                                 goto invalid;
 558                         /* RHS */
 559                         if (!rs[i].dst)
 560                                 ; /* missing is ok; it is the same as empty */
 561                         else if (!*rs[i].dst)
 562                                 ; /* empty is ok; it means "do not store" */
 563                         else if (!check_refname_format(rs[i].dst, flags))
 564                                 ; /* valid looking ref is ok */
 565                         else
 566                                 goto invalid;
 567                 } else {
 568                         /*
 569                          * LHS
 570                          * - empty is allowed; it means delete.
 571                          * - when wildcarded, it must be a valid looking ref.
 572                          * - otherwise, it must be an extended SHA-1, but
 573                          *   there is no existing way to validate this.
 574                          */
 575                         if (!*rs[i].src)
 576                                 ; /* empty is ok */
 577                         else if (is_glob) {
 578                                 if (check_refname_format(rs[i].src, flags))
 579                                         goto invalid;
 580                         }
 581                         else
 582                                 ; /* anything goes, for now */
 583                         /*
 584                          * RHS
 585                          * - missing is allowed, but LHS then must be a
 586                          *   valid looking ref.
 587                          * - empty is not allowed.
 588                          * - otherwise it must be a valid looking ref.
 589                          */
 590                         if (!rs[i].dst) {
 591                                 if (check_refname_format(rs[i].src, flags))
 592                                         goto invalid;
 593                         } else if (!*rs[i].dst) {
 594                                 goto invalid;
 595                         } else {
 596                                 if (check_refname_format(rs[i].dst, flags))
 597                                         goto invalid;
 598                         }
 599                 }
 600         }
 601         return rs;
 602
 603  invalid:
 604         if (verify) {
 605                 /*
 606                  * nr_refspec must be greater than zero and i must be valid
 607                  * since it is only possible to reach this point from within
 608                  * the for loop above.
 609                  */
 610                 free_refspecs(rs, i+1);
 611                 return NULL;
 612         }
 613         die("Invalid refspec '%s'", refspec[i]);
 614 }
 615
 616 int valid_fetch_refspec(const char *fetch_refspec_str)
 617 {
 618         struct refspec *refspec;
 619
 620         refspec = parse_refspec_internal(1, &fetch_refspec_str, 1, 1);
 621         free_refspecs(refspec, 1);
 622         return !!refspec;
 623 }
 624
 625 struct refspec *parse_fetch_refspec(int nr_refspec, const char **refspec)
 626 {
 627         return parse_refspec_internal(nr_refspec, refspec, 1, 0);
 628 }
 629
 630 static struct refspec *parse_push_refspec(int nr_refspec, const char **refspec)
 631 {
 632         return parse_refspec_internal(nr_refspec, refspec, 0, 0);
 633 }
 634
 635 void free_refspec(int nr_refspec, struct refspec *refspec)
 636 {
 637         int i;
 638         for (i = 0; i < nr_refspec; i++) {
 639                 free(refspec[i].src);
 640                 free(refspec[i].dst);
 641         }
 642         free(refspec);
 643 }
 644
 645 static int valid_remote_nick(const char *name)
 646 {
 647         if (!name[0] || is_dot_or_dotdot(name))
 648                 return 0;
 649         return !strchr(name, '/'); /* no slash */
 650 }
 651
 652 const char *remote_for_branch(struct branch *branch, int *explicit)
 653 {
 654         if (branch && branch->remote_name) {
 655                 if (explicit)
 656                         *explicit = 1;
 657                 return branch->remote_name;
 658         }
 659         if (explicit)
 660                 *explicit = 0;
 661         return "origin";
 662 }
 663
 664 const char *pushremote_for_branch(struct branch *branch, int *explicit)
 665 {
 666         if (branch && branch->pushremote_name) {
 667                 if (explicit)
 668                         *explicit = 1;
 669                 return branch->pushremote_name;
 670         }
 671         if (pushremote_name) {
 672                 if (explicit)
 673                         *explicit = 1;
 674                 return pushremote_name;
 675         }
 676         return remote_for_branch(branch, explicit);
 677 }
 678
 679 static struct remote *remote_get_1(const char *name,
 680                                    const char *(*get_default)(struct branch *, int *))
 681 {
 682         struct remote *ret;
 683         int name_given = 0;
 684
 685         read_config();
 686
 687         if (name)
 688                 name_given = 1;
 689         else
 690                 name = get_default(current_branch, &name_given);
 691
 692         ret = make_remote(name, 0);
 693         if (valid_remote_nick(name)) {
 694                 if (!valid_remote(ret))
 695                         read_remotes_file(ret);
 696                 if (!valid_remote(ret))
 697                         read_branches_file(ret);
 698         }
 699         if (name_given && !valid_remote(ret))
 700                 add_url_alias(ret, name);
 701         if (!valid_remote(ret))
 702                 return NULL;
 703         ret->fetch = parse_fetch_refspec(ret->fetch_refspec_nr, ret->fetch_refspec);
 704         ret->push = parse_push_refspec(ret->push_refspec_nr, ret->push_refspec);
 705         return ret;
 706 }
 707
 708 struct remote *remote_get(const char *name)
 709 {
 710         return remote_get_1(name, remote_for_branch);
 711 }
 712
 713 struct remote *pushremote_get(const char *name)
 714 {
 715         return remote_get_1(name, pushremote_for_branch);
 716 }
 717
 718 int remote_is_configured(const char *name)
 719 {
 720         struct remotes_hash_key lookup;
 721         struct hashmap_entry lookup_entry;
 722         read_config();
 723
 724         init_remotes_hash();
 725         lookup.str = name;
 726         lookup.len = strlen(name);
 727         hashmap_entry_init(&lookup_entry, memhash(name, lookup.len));
 728
 729         return hashmap_get(&remotes_hash, &lookup_entry, &lookup) != NULL;
 730 }
 731
 732 int for_each_remote(each_remote_fn fn, void *priv)
 733 {
 734         int i, result = 0;
 735         read_config();
 736         for (i = 0; i < remotes_nr && !result; i++) {
 737                 struct remote *r = remotes[i];
 738                 if (!r)
 739                         continue;
 740                 if (!r->fetch)
 741                         r->fetch = parse_fetch_refspec(r->fetch_refspec_nr,
 742                                                        r->fetch_refspec);
 743                 if (!r->push)
 744                         r->push = parse_push_refspec(r->push_refspec_nr,
 745                                                      r->push_refspec);
 746                 result = fn(r, priv);
 747         }
 748         return result;
 749 }
 750
 751 static void handle_duplicate(struct ref *ref1, struct ref *ref2)
 752 {
 753         if (strcmp(ref1->name, ref2->name)) {
 754                 if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 755                     ref2->fetch_head_status != FETCH_HEAD_IGNORE) {
 756                         die(_("Cannot fetch both %s and %s to %s"),
 757                             ref1->name, ref2->name, ref2->peer_ref->name);
 758                 } else if (ref1->fetch_head_status != FETCH_HEAD_IGNORE &&
 759                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 760                         warning(_("%s usually tracks %s, not %s"),
 761                                 ref2->peer_ref->name, ref2->name, ref1->name);
 762                 } else if (ref1->fetch_head_status == FETCH_HEAD_IGNORE &&
 763                            ref2->fetch_head_status == FETCH_HEAD_IGNORE) {
 764                         die(_("%s tracks both %s and %s"),
 765                             ref2->peer_ref->name, ref1->name, ref2->name);
 766                 } else {
 767                         /*
 768                          * This last possibility doesn't occur because
 769                          * FETCH_HEAD_IGNORE entries always appear at
 770                          * the end of the list.
 771                          */
 772                         die(_("Internal error"));
 773                 }
 774         }
 775         free(ref2->peer_ref);
 776         free(ref2);
 777 }
 778
 779 struct ref *ref_remove_duplicates(struct ref *ref_map)
 780 {
 781         struct string_list refs = STRING_LIST_INIT_NODUP;
 782         struct ref *retval = NULL;
 783         struct ref **p = &retval;
 784
 785         while (ref_map) {
 786                 struct ref *ref = ref_map;
 787
 788                 ref_map = ref_map->next;
 789                 ref->next = NULL;
 790
 791                 if (!ref->peer_ref) {
 792                         *p = ref;
 793                         p = &ref->next;
 794                 } else {
 795                         struct string_list_item *item =
 796                                 string_list_insert(&refs, ref->peer_ref->name);
 797
 798                         if (item->util) {
 799                                 /* Entry already existed */
 800                                 handle_duplicate((struct ref *)item->util, ref);
 801                         } else {
 802                                 *p = ref;
 803                                 p = &ref->next;
 804                                 item->util = ref;
 805                         }
 806                 }
 807         }
 808
 809         string_list_clear(&refs, 0);
 810         return retval;
 811 }
 812
 813 int remote_has_url(struct remote *remote, const char *url)
 814 {
 815         int i;
 816         for (i = 0; i < remote->url_nr; i++) {
 817                 if (!strcmp(remote->url[i], url))
 818                         return 1;
 819         }
 820         return 0;
 821 }
 822
 823 static int match_name_with_pattern(const char *key, const char *name,
 824                                    const char *value, char **result)
 825 {
 826         const char *kstar = strchr(key, '*');
 827         size_t klen;
 828         size_t ksuffixlen;
 829         size_t namelen;
 830         int ret;
 831         if (!kstar)
 832                 die("Key '%s' of pattern had no '*'", key);
 833         klen = kstar - key;
 834         ksuffixlen = strlen(kstar + 1);
 835         namelen = strlen(name);
 836         ret = !strncmp(name, key, klen) && namelen >= klen + ksuffixlen &&
 837                 !memcmp(name + namelen - ksuffixlen, kstar + 1, ksuffixlen);
 838         if (ret && value) {
 839                 struct strbuf sb = STRBUF_INIT;
 840                 const char *vstar = strchr(value, '*');
 841                 if (!vstar)
 842                         die("Value '%s' of pattern has no '*'", value);
 843                 strbuf_add(&sb, value, vstar - value);
 844                 strbuf_add(&sb, name + klen, namelen - klen - ksuffixlen);
 845                 strbuf_addstr(&sb, vstar + 1);
 846                 *result = strbuf_detach(&sb, NULL);
 847         }
 848         return ret;
 849 }
 850
 851 static void query_refspecs_multiple(struct refspec *refs, int ref_count, struct refspec *query, struct string_list *results)
 852 {
 853         int i;
 854         int find_src = !query->src;
 855
 856         if (find_src && !query->dst)
 857                 error("query_refspecs_multiple: need either src or dst");
 858
 859         for (i = 0; i < ref_count; i++) {
 860                 struct refspec *refspec = &refs[i];
 861                 const char *key = find_src ? refspec->dst : refspec->src;
 862                 const char *value = find_src ? refspec->src : refspec->dst;
 863                 const char *needle = find_src ? query->dst : query->src;
 864                 char **result = find_src ? &query->src : &query->dst;
 865
 866                 if (!refspec->dst)
 867                         continue;
 868                 if (refspec->pattern) {
 869                         if (match_name_with_pattern(key, needle, value, result))
 870                                 string_list_append_nodup(results, *result);
 871                 } else if (!strcmp(needle, key)) {
 872                         string_list_append(results, value);
 873                 }
 874         }
 875 }
 876
 877 int query_refspecs(struct refspec *refs, int ref_count, struct refspec *query)
 878 {
 879         int i;
 880         int find_src = !query->src;
 881         const char *needle = find_src ? query->dst : query->src;
 882         char **result = find_src ? &query->src : &query->dst;
 883
 884         if (find_src && !query->dst)
 885                 return error("query_refspecs: need either src or dst");
 886
 887         for (i = 0; i < ref_count; i++) {
 888                 struct refspec *refspec = &refs[i];
 889                 const char *key = find_src ? refspec->dst : refspec->src;
 890                 const char *value = find_src ? refspec->src : refspec->dst;
 891
 892                 if (!refspec->dst)
 893                         continue;
 894                 if (refspec->pattern) {
 895                         if (match_name_with_pattern(key, needle, value, result)) {
 896                                 query->force = refspec->force;
 897                                 return 0;
 898                         }
 899                 } else if (!strcmp(needle, key)) {
 900                         *result = xstrdup(value);
 901                         query->force = refspec->force;
 902                         return 0;
 903                 }
 904         }
 905         return -1;
 906 }
 907
 908 char *apply_refspecs(struct refspec *refspecs, int nr_refspec,
 909                      const char *name)
 910 {
 911         struct refspec query;
 912
 913         memset(&query, 0, sizeof(struct refspec));
 914         query.src = (char *)name;
 915
 916         if (query_refspecs(refspecs, nr_refspec, &query))
 917                 return NULL;
 918
 919         return query.dst;
 920 }
 921
 922 int remote_find_tracking(struct remote *remote, struct refspec *refspec)
 923 {
 924         return query_refspecs(remote->fetch, remote->fetch_refspec_nr, refspec);
 925 }
 926
 927 static struct ref *alloc_ref_with_prefix(const char *prefix, size_t prefixlen,
 928                 const char *name)
 929 {
 930         size_t len = strlen(name);
 931         struct ref *ref = xcalloc(1, sizeof(struct ref) + prefixlen + len + 1);
 932         memcpy(ref->name, prefix, prefixlen);
 933         memcpy(ref->name + prefixlen, name, len);
 934         return ref;
 935 }
 936
 937 struct ref *alloc_ref(const char *name)
 938 {
 939         return alloc_ref_with_prefix("", 0, name);
 940 }
 941
 942 struct ref *copy_ref(const struct ref *ref)
 943 {
 944         struct ref *cpy;
 945         size_t len;
 946         if (!ref)
 947                 return NULL;
 948         len = strlen(ref->name);
 949         cpy = xmalloc(sizeof(struct ref) + len + 1);
 950         memcpy(cpy, ref, sizeof(struct ref) + len + 1);
 951         cpy->next = NULL;
 952         cpy->symref = xstrdup_or_null(ref->symref);
 953         cpy->remote_status = xstrdup_or_null(ref->remote_status);
 954         cpy->peer_ref = copy_ref(ref->peer_ref);
 955         return cpy;
 956 }
 957
 958 struct ref *copy_ref_list(const struct ref *ref)
 959 {
 960         struct ref *ret = NULL;
 961         struct ref **tail = &ret;
 962         while (ref) {
 963                 *tail = copy_ref(ref);
 964                 ref = ref->next;
 965                 tail = &((*tail)->next);
 966         }
 967         return ret;
 968 }
 969
 970 static void free_ref(struct ref *ref)
 971 {
 972         if (!ref)
 973                 return;
 974         free_ref(ref->peer_ref);
 975         free(ref->remote_status);
 976         free(ref->symref);
 977         free(ref);
 978 }
 979
 980 void free_refs(struct ref *ref)
 981 {
 982         struct ref *next;
 983         while (ref) {
 984                 next = ref->next;
 985                 free_ref(ref);
 986                 ref = next;
 987         }
 988 }
 989
 990 int ref_compare_name(const void *va, const void *vb)
 991 {
 992         const struct ref *a = va, *b = vb;
 993         return strcmp(a->name, b->name);
 994 }
 995
 996 static void *ref_list_get_next(const void *a)
 997 {
 998         return ((const struct ref *)a)->next;
 999 }
1000
1001 static void ref_list_set_next(void *a, void *next)
1002 {
1003         ((struct ref *)a)->next = next;
1004 }
1005
1006 void sort_ref_list(struct ref **l, int (*cmp)(const void *, const void *))
1007 {
1008         *l = llist_mergesort(*l, ref_list_get_next, ref_list_set_next, cmp);
1009 }
1010
1011 int count_refspec_match(const char *pattern,
1012                         struct ref *refs,
1013                         struct ref **matched_ref)
1014 {
1015         int patlen = strlen(pattern);
1016         struct ref *matched_weak = NULL;
1017         struct ref *matched = NULL;
1018         int weak_match = 0;
1019         int match = 0;
1020
1021         for (weak_match = match = 0; refs; refs = refs->next) {
1022                 char *name = refs->name;
1023                 int namelen = strlen(name);
1024
1025                 if (!refname_match(pattern, name))
1026                         continue;
1027
1028                 /* A match is "weak" if it is with refs outside
1029                  * heads or tags, and did not specify the pattern
1030                  * in full (e.g. "refs/remotes/origin/master") or at
1031                  * least from the toplevel (e.g. "remotes/origin/master");
1032                  * otherwise "git push $URL master" would result in
1033                  * ambiguity between remotes/origin/master and heads/master
1034                  * at the remote site.
1035                  */
1036                 if (namelen != patlen &&
1037                     patlen != namelen - 5 &&
1038                     !starts_with(name, "refs/heads/") &&
1039                     !starts_with(name, "refs/tags/")) {
1040                         /* We want to catch the case where only weak
1041                          * matches are found and there are multiple
1042                          * matches, and where more than one strong
1043                          * matches are found, as ambiguous.  One
1044                          * strong match with zero or more weak matches
1045                          * are acceptable as a unique match.
1046                          */
1047                         matched_weak = refs;
1048                         weak_match++;
1049                 }
1050                 else {
1051                         matched = refs;
1052                         match++;
1053                 }
1054         }
1055         if (!matched) {
1056                 if (matched_ref)
1057                         *matched_ref = matched_weak;
1058                 return weak_match;
1059         }
1060         else {
1061                 if (matched_ref)
1062                         *matched_ref = matched;
1063                 return match;
1064         }
1065 }
1066
1067 static void tail_link_ref(struct ref *ref, struct ref ***tail)
1068 {
1069         **tail = ref;
1070         while (ref->next)
1071                 ref = ref->next;
1072         *tail = &ref->next;
1073 }
1074
1075 static struct ref *alloc_delete_ref(void)
1076 {
1077         struct ref *ref = alloc_ref("(delete)");
1078         oidclr(&ref->new_oid);
1079         return ref;
1080 }
1081
1082 static int try_explicit_object_name(const char *name,
1083                                     struct ref **match)
1084 {
1085         struct object_id oid;
1086
1087         if (!*name) {
1088                 if (match)
1089                         *match = alloc_delete_ref();
1090                 return 0;
1091         }
1092
1093         if (get_sha1(name, oid.hash))
1094                 return -1;
1095
1096         if (match) {
1097                 *match = alloc_ref(name);
1098                 oidcpy(&(*match)->new_oid, &oid);
1099         }
1100         return 0;
1101 }
1102
1103 static struct ref *make_linked_ref(const char *name, struct ref ***tail)
1104 {
1105         struct ref *ret = alloc_ref(name);
1106         tail_link_ref(ret, tail);
1107         return ret;
1108 }
1109
1110 static char *guess_ref(const char *name, struct ref *peer)
1111 {
1112         struct strbuf buf = STRBUF_INIT;
1113         struct object_id oid;
1114
1115         const char *r = resolve_ref_unsafe(peer->name, RESOLVE_REF_READING,
1116                                            oid.hash, NULL);
1117         if (!r)
1118                 return NULL;
1119
1120         if (starts_with(r, "refs/heads/"))
1121                 strbuf_addstr(&buf, "refs/heads/");
1122         else if (starts_with(r, "refs/tags/"))
1123                 strbuf_addstr(&buf, "refs/tags/");
1124         else
1125                 return NULL;
1126
1127         strbuf_addstr(&buf, name);
1128         return strbuf_detach(&buf, NULL);
1129 }
1130
1131 static int match_explicit_lhs(struct ref *src,
1132                               struct refspec *rs,
1133                               struct ref **match,
1134                               int *allocated_match)
1135 {
1136         switch (count_refspec_match(rs->src, src, match)) {
1137         case 1:
1138                 if (allocated_match)
1139                         *allocated_match = 0;
1140                 return 0;
1141         case 0:
1142                 /* The source could be in the get_sha1() format
1143                  * not a reference name.  :refs/other is a
1144                  * way to delete 'other' ref at the remote end.
1145                  */
1146                 if (try_explicit_object_name(rs->src, match) < 0)
1147                         return error("src refspec %s does not match any.", rs->src);
1148                 if (allocated_match)
1149                         *allocated_match = 1;
1150                 return 0;
1151         default:
1152                 return error("src refspec %s matches more than one.", rs->src);
1153         }
1154 }
1155
1156 static int match_explicit(struct ref *src, struct ref *dst,
1157                           struct ref ***dst_tail,
1158                           struct refspec *rs)
1159 {
1160         struct ref *matched_src, *matched_dst;
1161         int allocated_src;
1162
1163         const char *dst_value = rs->dst;
1164         char *dst_guess;
1165
1166         if (rs->pattern || rs->matching)
1167                 return 0;
1168
1169         matched_src = matched_dst = NULL;
1170         if (match_explicit_lhs(src, rs, &matched_src, &allocated_src) < 0)
1171                 return -1;
1172
1173         if (!dst_value) {
1174                 struct object_id oid;
1175                 int flag;
1176
1177                 dst_value = resolve_ref_unsafe(matched_src->name,
1178                                                RESOLVE_REF_READING,
1179                                                oid.hash, &flag);
1180                 if (!dst_value ||
1181                     ((flag & REF_ISSYMREF) &&
1182                      !starts_with(dst_value, "refs/heads/")))
1183                         die("%s cannot be resolved to branch.",
1184                             matched_src->name);
1185         }
1186
1187         switch (count_refspec_match(dst_value, dst, &matched_dst)) {
1188         case 1:
1189                 break;
1190         case 0:
1191                 if (starts_with(dst_value, "refs/"))
1192                         matched_dst = make_linked_ref(dst_value, dst_tail);
1193                 else if (is_null_oid(&matched_src->new_oid))
1194                         error("unable to delete '%s': remote ref does not exist",
1195                               dst_value);
1196                 else if ((dst_guess = guess_ref(dst_value, matched_src)))
1197                         matched_dst = make_linked_ref(dst_guess, dst_tail);
1198                 else
1199                         error("unable to push to unqualified destination: %s\n"
1200                               "The destination refspec neither matches an "
1201                               "existing ref on the remote nor\n"
1202                               "begins with refs/, and we are unable to "
1203                               "guess a prefix based on the source ref.",
1204                               dst_value);
1205                 break;
1206         default:
1207                 matched_dst = NULL;
1208                 error("dst refspec %s matches more than one.",
1209                       dst_value);
1210                 break;
1211         }
1212         if (!matched_dst)
1213                 return -1;
1214         if (matched_dst->peer_ref)
1215                 return error("dst ref %s receives from more than one src.",
1216                       matched_dst->name);
1217         else {
1218                 matched_dst->peer_ref = allocated_src ?
1219                                         matched_src :
1220                                         copy_ref(matched_src);
1221                 matched_dst->force = rs->force;
1222         }
1223         return 0;
1224 }
1225
1226 static int match_explicit_refs(struct ref *src, struct ref *dst,
1227                                struct ref ***dst_tail, struct refspec *rs,
1228                                int rs_nr)
1229 {
1230         int i, errs;
1231         for (i = errs = 0; i < rs_nr; i++)
1232                 errs += match_explicit(src, dst, dst_tail, &rs[i]);
1233         return errs;
1234 }
1235
1236 static char *get_ref_match(const struct refspec *rs, int rs_nr, const struct ref *ref,
1237                 int send_mirror, int direction, const struct refspec **ret_pat)
1238 {
1239         const struct refspec *pat;
1240         char *name;
1241         int i;
1242         int matching_refs = -1;
1243         for (i = 0; i < rs_nr; i++) {
1244                 if (rs[i].matching &&
1245                     (matching_refs == -1 || rs[i].force)) {
1246                         matching_refs = i;
1247                         continue;
1248                 }
1249
1250                 if (rs[i].pattern) {
1251                         const char *dst_side = rs[i].dst ? rs[i].dst : rs[i].src;
1252                         int match;
1253                         if (direction == FROM_SRC)
1254                                 match = match_name_with_pattern(rs[i].src, ref->name, dst_side, &name);
1255                         else
1256                                 match = match_name_with_pattern(dst_side, ref->name, rs[i].src, &name);
1257                         if (match) {
1258                                 matching_refs = i;
1259                                 break;
1260                         }
1261                 }
1262         }
1263         if (matching_refs == -1)
1264                 return NULL;
1265
1266         pat = rs + matching_refs;
1267         if (pat->matching) {
1268                 /*
1269                  * "matching refs"; traditionally we pushed everything
1270                  * including refs outside refs/heads/ hierarchy, but
1271                  * that does not make much sense these days.
1272                  */
1273                 if (!send_mirror && !starts_with(ref->name, "refs/heads/"))
1274                         return NULL;
1275                 name = xstrdup(ref->name);
1276         }
1277         if (ret_pat)
1278                 *ret_pat = pat;
1279         return name;
1280 }
1281
1282 static struct ref **tail_ref(struct ref **head)
1283 {
1284         struct ref **tail = head;
1285         while (*tail)
1286                 tail = &((*tail)->next);
1287         return tail;
1288 }
1289
1290 struct tips {
1291         struct commit **tip;
1292         int nr, alloc;
1293 };
1294
1295 static void add_to_tips(struct tips *tips, const struct object_id *oid)
1296 {
1297         struct commit *commit;
1298
1299         if (is_null_oid(oid))
1300                 return;
1301         commit = lookup_commit_reference_gently(oid->hash, 1);
1302         if (!commit || (commit->object.flags & TMP_MARK))
1303                 return;
1304         commit->object.flags |= TMP_MARK;
1305         ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
1306         tips->tip[tips->nr++] = commit;
1307 }
1308
1309 static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
1310 {
1311         struct string_list dst_tag = STRING_LIST_INIT_NODUP;
1312         struct string_list src_tag = STRING_LIST_INIT_NODUP;
1313         struct string_list_item *item;
1314         struct ref *ref;
1315         struct tips sent_tips;
1316
1317         /*
1318          * Collect everything we know they would have at the end of
1319          * this push, and collect all tags they have.
1320          */
1321         memset(&sent_tips, 0, sizeof(sent_tips));
1322         for (ref = *dst; ref; ref = ref->next) {
1323                 if (ref->peer_ref &&
1324                     !is_null_oid(&ref->peer_ref->new_oid))
1325                         add_to_tips(&sent_tips, &ref->peer_ref->new_oid);
1326                 else
1327                         add_to_tips(&sent_tips, &ref->old_oid);
1328                 if (starts_with(ref->name, "refs/tags/"))
1329                         string_list_append(&dst_tag, ref->name);
1330         }
1331         clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
1332
1333         string_list_sort(&dst_tag);
1334
1335         /* Collect tags they do not have. */
1336         for (ref = src; ref; ref = ref->next) {
1337                 if (!starts_with(ref->name, "refs/tags/"))
1338                         continue; /* not a tag */
1339                 if (string_list_has_string(&dst_tag, ref->name))
1340                         continue; /* they already have it */
1341                 if (sha1_object_info(ref->new_oid.hash, NULL) != OBJ_TAG)
1342                         continue; /* be conservative */
1343                 item = string_list_append(&src_tag, ref->name);
1344                 item->util = ref;
1345         }
1346         string_list_clear(&dst_tag, 0);
1347
1348         /*
1349          * At this point, src_tag lists tags that are missing from
1350          * dst, and sent_tips lists the tips we are pushing or those
1351          * that we know they already have. An element in the src_tag
1352          * that is an ancestor of any of the sent_tips needs to be
1353          * sent to the other side.
1354          */
1355         if (sent_tips.nr) {
1356                 for_each_string_list_item(item, &src_tag) {
1357                         struct ref *ref = item->util;
1358                         struct ref *dst_ref;
1359                         struct commit *commit;
1360
1361                         if (is_null_oid(&ref->new_oid))
1362                                 continue;
1363                         commit = lookup_commit_reference_gently(ref->new_oid.hash, 1);
1364                         if (!commit)
1365                                 /* not pushing a commit, which is not an error */
1366                                 continue;
1367
1368                         /*
1369                          * Is this tag, which they do not have, reachable from
1370                          * any of the commits we are sending?
1371                          */
1372                         if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
1373                                 continue;
1374
1375                         /* Add it in */
1376                         dst_ref = make_linked_ref(ref->name, dst_tail);
1377                         oidcpy(&dst_ref->new_oid, &ref->new_oid);
1378                         dst_ref->peer_ref = copy_ref(ref);
1379                 }
1380         }
1381         string_list_clear(&src_tag, 0);
1382         free(sent_tips.tip);
1383 }
1384
1385 struct ref *find_ref_by_name(const struct ref *list, const char *name)
1386 {
1387         for ( ; list; list = list->next)
1388                 if (!strcmp(list->name, name))
1389                         return (struct ref *)list;
1390         return NULL;
1391 }
1392
1393 static void prepare_ref_index(struct string_list *ref_index, struct ref *ref)
1394 {
1395         for ( ; ref; ref = ref->next)
1396                 string_list_append_nodup(ref_index, ref->name)->util = ref;
1397
1398         string_list_sort(ref_index);
1399 }
1400
1401 /*
1402  * Given only the set of local refs, sanity-check the set of push
1403  * refspecs. We can't catch all errors that match_push_refs would,
1404  * but we can catch some errors early before even talking to the
1405  * remote side.
1406  */
1407 int check_push_refs(struct ref *src, int nr_refspec, const char **refspec_names)
1408 {
1409         struct refspec *refspec = parse_push_refspec(nr_refspec, refspec_names);
1410         int ret = 0;
1411         int i;
1412
1413         for (i = 0; i < nr_refspec; i++) {
1414                 struct refspec *rs = refspec + i;
1415
1416                 if (rs->pattern || rs->matching)
1417                         continue;
1418
1419                 ret |= match_explicit_lhs(src, rs, NULL, NULL);
1420         }
1421
1422         free_refspec(nr_refspec, refspec);
1423         return ret;
1424 }
1425
1426 /*
1427  * Given the set of refs the local repository has, the set of refs the
1428  * remote repository has, and the refspec used for push, determine
1429  * what remote refs we will update and with what value by setting
1430  * peer_ref (which object is being pushed) and force (if the push is
1431  * forced) in elements of "dst". The function may add new elements to
1432  * dst (e.g. pushing to a new branch, done in match_explicit_refs).
1433  */
1434 int match_push_refs(struct ref *src, struct ref **dst,
1435                     int nr_refspec, const char **refspec, int flags)
1436 {
1437         struct refspec *rs;
1438         int send_all = flags & MATCH_REFS_ALL;
1439         int send_mirror = flags & MATCH_REFS_MIRROR;
1440         int send_prune = flags & MATCH_REFS_PRUNE;
1441         int errs;
1442         static const char *default_refspec[] = { ":", NULL };
1443         struct ref *ref, **dst_tail = tail_ref(dst);
1444         struct string_list dst_ref_index = STRING_LIST_INIT_NODUP;
1445
1446         if (!nr_refspec) {
1447                 nr_refspec = 1;
1448                 refspec = default_refspec;
1449         }
1450         rs = parse_push_refspec(nr_refspec, (const char **) refspec);
1451         errs = match_explicit_refs(src, *dst, &dst_tail, rs, nr_refspec);
1452
1453         /* pick the remainder */
1454         for (ref = src; ref; ref = ref->next) {
1455                 struct string_list_item *dst_item;
1456                 struct ref *dst_peer;
1457                 const struct refspec *pat = NULL;
1458                 char *dst_name;
1459
1460                 dst_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_SRC, &pat);
1461                 if (!dst_name)
1462                         continue;
1463
1464                 if (!dst_ref_index.nr)
1465                         prepare_ref_index(&dst_ref_index, *dst);
1466
1467                 dst_item = string_list_lookup(&dst_ref_index, dst_name);
1468                 dst_peer = dst_item ? dst_item->util : NULL;
1469                 if (dst_peer) {
1470                         if (dst_peer->peer_ref)
1471                                 /* We're already sending something to this ref. */
1472                                 goto free_name;
1473                 } else {
1474                         if (pat->matching && !(send_all || send_mirror))
1475                                 /*
1476                                  * Remote doesn't have it, and we have no
1477                                  * explicit pattern, and we don't have
1478                                  * --all or --mirror.
1479                                  */
1480                                 goto free_name;
1481
1482                         /* Create a new one and link it */
1483                         dst_peer = make_linked_ref(dst_name, &dst_tail);
1484                         oidcpy(&dst_peer->new_oid, &ref->new_oid);
1485                         string_list_insert(&dst_ref_index,
1486                                 dst_peer->name)->util = dst_peer;
1487                 }
1488                 dst_peer->peer_ref = copy_ref(ref);
1489                 dst_peer->force = pat->force;
1490         free_name:
1491                 free(dst_name);
1492         }
1493
1494         string_list_clear(&dst_ref_index, 0);
1495
1496         if (flags & MATCH_REFS_FOLLOW_TAGS)
1497                 add_missing_tags(src, dst, &dst_tail);
1498
1499         if (send_prune) {
1500                 struct string_list src_ref_index = STRING_LIST_INIT_NODUP;
1501                 /* check for missing refs on the remote */
1502                 for (ref = *dst; ref; ref = ref->next) {
1503                         char *src_name;
1504
1505                         if (ref->peer_ref)
1506                                 /* We're already sending something to this ref. */
1507                                 continue;
1508
1509                         src_name = get_ref_match(rs, nr_refspec, ref, send_mirror, FROM_DST, NULL);
1510                         if (src_name) {
1511                                 if (!src_ref_index.nr)
1512                                         prepare_ref_index(&src_ref_index, src);
1513                                 if (!string_list_has_string(&src_ref_index,
1514                                             src_name))
1515                                         ref->peer_ref = alloc_delete_ref();
1516                                 free(src_name);
1517                         }
1518                 }
1519                 string_list_clear(&src_ref_index, 0);
1520         }
1521         if (errs)
1522                 return -1;
1523         return 0;
1524 }
1525
1526 void set_ref_status_for_push(struct ref *remote_refs, int send_mirror,
1527                              int force_update)
1528 {
1529         struct ref *ref;
1530
1531         for (ref = remote_refs; ref; ref = ref->next) {
1532                 int force_ref_update = ref->force || force_update;
1533                 int reject_reason = 0;
1534
1535                 if (ref->peer_ref)
1536                         oidcpy(&ref->new_oid, &ref->peer_ref->new_oid);
1537                 else if (!send_mirror)
1538                         continue;
1539
1540                 ref->deletion = is_null_oid(&ref->new_oid);
1541                 if (!ref->deletion &&
1542                         !oidcmp(&ref->old_oid, &ref->new_oid)) {
1543                         ref->status = REF_STATUS_UPTODATE;
1544                         continue;
1545                 }
1546
1547                 /*
1548                  * Bypass the usual "must fast-forward" check but
1549                  * replace it with a weaker "the old value must be
1550                  * this value we observed".  If the remote ref has
1551                  * moved and is now different from what we expect,
1552                  * reject any push.
1553                  *
1554                  * It also is an error if the user told us to check
1555                  * with the remote-tracking branch to find the value
1556                  * to expect, but we did not have such a tracking
1557                  * branch.
1558                  */
1559                 if (ref->expect_old_sha1) {
1560                         if (ref->expect_old_no_trackback ||
1561                             oidcmp(&ref->old_oid, &ref->old_oid_expect))
1562                                 reject_reason = REF_STATUS_REJECT_STALE;
1563                 }
1564
1565                 /*
1566                  * The usual "must fast-forward" rules.
1567                  *
1568                  * Decide whether an individual refspec A:B can be
1569                  * pushed.  The push will succeed if any of the
1570                  * following are true:
1571                  *
1572                  * (1) the remote reference B does not exist
1573                  *
1574                  * (2) the remote reference B is being removed (i.e.,
1575                  *     pushing :B where no source is specified)
1576                  *
1577                  * (3) the destination is not under refs/tags/, and
1578                  *     if the old and new value is a commit, the new
1579                  *     is a descendant of the old.
1580                  *
1581                  * (4) it is forced using the +A:B notation, or by
1582                  *     passing the --force argument
1583                  */
1584
1585                 else if (!ref->deletion && !is_null_oid(&ref->old_oid)) {
1586                         if (starts_with(ref->name, "refs/tags/"))
1587                                 reject_reason = REF_STATUS_REJECT_ALREADY_EXISTS;
1588                         else if (!has_object_file(&ref->old_oid))
1589                                 reject_reason = REF_STATUS_REJECT_FETCH_FIRST;
1590                         else if (!lookup_commit_reference_gently(ref->old_oid.hash, 1) ||
1591                                  !lookup_commit_reference_gently(ref->new_oid.hash, 1))
1592                                 reject_reason = REF_STATUS_REJECT_NEEDS_FORCE;
1593                         else if (!ref_newer(&ref->new_oid, &ref->old_oid))
1594                                 reject_reason = REF_STATUS_REJECT_NONFASTFORWARD;
1595                 }
1596
1597                 /*
1598                  * "--force" will defeat any rejection implemented
1599                  * by the rules above.
1600                  */
1601                 if (!force_ref_update)
1602                         ref->status = reject_reason;
1603                 else if (reject_reason)
1604                         ref->forced_update = 1;
1605         }
1606 }
1607
1608 static void set_merge(struct branch *ret)
1609 {
1610         struct remote *remote;
1611         char *ref;
1612         struct object_id oid;
1613         int i;
1614
1615         if (!ret)
1616                 return; /* no branch */
1617         if (ret->merge)
1618                 return; /* already run */
1619         if (!ret->remote_name || !ret->merge_nr) {
1620                 /*
1621                  * no merge config; let's make sure we don't confuse callers
1622                  * with a non-zero merge_nr but a NULL merge
1623                  */
1624                 ret->merge_nr = 0;
1625                 return;
1626         }
1627
1628         remote = remote_get(ret->remote_name);
1629
1630         ret->merge = xcalloc(ret->merge_nr, sizeof(*ret->merge));
1631         for (i = 0; i < ret->merge_nr; i++) {
1632                 ret->merge[i] = xcalloc(1, sizeof(**ret->merge));
1633                 ret->merge[i]->src = xstrdup(ret->merge_name[i]);
1634                 if (!remote_find_tracking(remote, ret->merge[i]) ||
1635                     strcmp(ret->remote_name, "."))
1636                         continue;
1637                 if (dwim_ref(ret->merge_name[i], strlen(ret->merge_name[i]),
1638                              oid.hash, &ref) == 1)
1639                         ret->merge[i]->dst = ref;
1640                 else
1641                         ret->merge[i]->dst = xstrdup(ret->merge_name[i]);
1642         }
1643 }
1644
1645 struct branch *branch_get(const char *name)
1646 {
1647         struct branch *ret;
1648
1649         read_config();
1650         if (!name || !*name || !strcmp(name, "HEAD"))
1651                 ret = current_branch;
1652         else
1653                 ret = make_branch(name, 0);
1654         set_merge(ret);
1655         return ret;
1656 }
1657
1658 int branch_has_merge_config(struct branch *branch)
1659 {
1660         return branch && !!branch->merge;
1661 }
1662
1663 int branch_merge_matches(struct branch *branch,
1664                                  int i,
1665                                  const char *refname)
1666 {
1667         if (!branch || i < 0 || i >= branch->merge_nr)
1668                 return 0;
1669         return refname_match(branch->merge[i]->src, refname);
1670 }
1671
1672 __attribute((format (printf,2,3)))
1673 static const char *error_buf(struct strbuf *err, const char *fmt, ...)
1674 {
1675         if (err) {
1676                 va_list ap;
1677                 va_start(ap, fmt);
1678                 strbuf_vaddf(err, fmt, ap);
1679                 va_end(ap);
1680         }
1681         return NULL;
1682 }
1683
1684 const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
1685 {
1686         if (!branch)
1687                 return error_buf(err, _("HEAD does not point to a branch"));
1688
1689         if (!branch->merge || !branch->merge[0]) {
1690                 /*
1691                  * no merge config; is it because the user didn't define any,
1692                  * or because it is not a real branch, and get_branch
1693                  * auto-vivified it?
1694                  */
1695                 if (!ref_exists(branch->refname))
1696                         return error_buf(err, _("no such branch: '%s'"),
1697                                          branch->name);
1698                 return error_buf(err,
1699                                  _("no upstream configured for branch '%s'"),
1700                                  branch->name);
1701         }
1702
1703         if (!branch->merge[0]->dst)
1704                 return error_buf(err,
1705                                  _("upstream branch '%s' not stored as a remote-tracking branch"),
1706                                  branch->merge[0]->src);
1707
1708         return branch->merge[0]->dst;
1709 }
1710
1711 static const char *tracking_for_push_dest(struct remote *remote,
1712                                           const char *refname,
1713                                           struct strbuf *err)
1714 {
1715         char *ret;
1716
1717         ret = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
1718         if (!ret)
1719                 return error_buf(err,
1720                                  _("push destination '%s' on remote '%s' has no local tracking branch"),
1721                                  refname, remote->name);
1722         return ret;
1723 }
1724
1725 static const char *branch_get_push_1(struct branch *branch, struct strbuf *err)
1726 {
1727         struct remote *remote;
1728
1729         if (!branch)
1730                 return error_buf(err, _("HEAD does not point to a branch"));
1731
1732         remote = remote_get(pushremote_for_branch(branch, NULL));
1733         if (!remote)
1734                 return error_buf(err,
1735                                  _("branch '%s' has no remote for pushing"),
1736                                  branch->name);
1737
1738         if (remote->push_refspec_nr) {
1739                 char *dst;
1740                 const char *ret;
1741
1742                 dst = apply_refspecs(remote->push, remote->push_refspec_nr,
1743                                      branch->refname);
1744                 if (!dst)
1745                         return error_buf(err,
1746                                          _("push refspecs for '%s' do not include '%s'"),
1747                                          remote->name, branch->name);
1748
1749                 ret = tracking_for_push_dest(remote, dst, err);
1750                 free(dst);
1751                 return ret;
1752         }
1753
1754         if (remote->mirror)
1755                 return tracking_for_push_dest(remote, branch->refname, err);
1756
1757         switch (push_default) {
1758         case PUSH_DEFAULT_NOTHING:
1759                 return error_buf(err, _("push has no destination (push.default is 'nothing')"));
1760
1761         case PUSH_DEFAULT_MATCHING:
1762         case PUSH_DEFAULT_CURRENT:
1763                 return tracking_for_push_dest(remote, branch->refname, err);
1764
1765         case PUSH_DEFAULT_UPSTREAM:
1766                 return branch_get_upstream(branch, err);
1767
1768         case PUSH_DEFAULT_UNSPECIFIED:
1769         case PUSH_DEFAULT_SIMPLE:
1770                 {
1771                         const char *up, *cur;
1772
1773                         up = branch_get_upstream(branch, err);
1774                         if (!up)
1775                                 return NULL;
1776                         cur = tracking_for_push_dest(remote, branch->refname, err);
1777                         if (!cur)
1778                                 return NULL;
1779                         if (strcmp(cur, up))
1780                                 return error_buf(err,
1781                                                  _("cannot resolve 'simple' push to a single destination"));
1782                         return cur;
1783                 }
1784         }
1785
1786         die("BUG: unhandled push situation");
1787 }
1788
1789 const char *branch_get_push(struct branch *branch, struct strbuf *err)
1790 {
1791         if (!branch->push_tracking_ref)
1792                 branch->push_tracking_ref = branch_get_push_1(branch, err);
1793         return branch->push_tracking_ref;
1794 }
1795
1796 static int ignore_symref_update(const char *refname)
1797 {
1798         struct object_id oid;
1799         int flag;
1800
1801         if (!resolve_ref_unsafe(refname, 0, oid.hash, &flag))
1802                 return 0; /* non-existing refs are OK */
1803         return (flag & REF_ISSYMREF);
1804 }
1805
1806 /*
1807  * Create and return a list of (struct ref) consisting of copies of
1808  * each remote_ref that matches refspec.  refspec must be a pattern.
1809  * Fill in the copies' peer_ref to describe the local tracking refs to
1810  * which they map.  Omit any references that would map to an existing
1811  * local symbolic ref.
1812  */
1813 static struct ref *get_expanded_map(const struct ref *remote_refs,
1814                                     const struct refspec *refspec)
1815 {
1816         const struct ref *ref;
1817         struct ref *ret = NULL;
1818         struct ref **tail = &ret;
1819
1820         for (ref = remote_refs; ref; ref = ref->next) {
1821                 char *expn_name = NULL;
1822
1823                 if (strchr(ref->name, '^'))
1824                         continue; /* a dereference item */
1825                 if (match_name_with_pattern(refspec->src, ref->name,
1826                                             refspec->dst, &expn_name) &&
1827                     !ignore_symref_update(expn_name)) {
1828                         struct ref *cpy = copy_ref(ref);
1829
1830                         cpy->peer_ref = alloc_ref(expn_name);
1831                         if (refspec->force)
1832                                 cpy->peer_ref->force = 1;
1833                         *tail = cpy;
1834                         tail = &cpy->next;
1835                 }
1836                 free(expn_name);
1837         }
1838
1839         return ret;
1840 }
1841
1842 static const struct ref *find_ref_by_name_abbrev(const struct ref *refs, const char *name)
1843 {
1844         const struct ref *ref;
1845         for (ref = refs; ref; ref = ref->next) {
1846                 if (refname_match(name, ref->name))
1847                         return ref;
1848         }
1849         return NULL;
1850 }
1851
1852 struct ref *get_remote_ref(const struct ref *remote_refs, const char *name)
1853 {
1854         const struct ref *ref = find_ref_by_name_abbrev(remote_refs, name);
1855
1856         if (!ref)
1857                 return NULL;
1858
1859         return copy_ref(ref);
1860 }
1861
1862 static struct ref *get_local_ref(const char *name)
1863 {
1864         if (!name || name[0] == '\0')
1865                 return NULL;
1866
1867         if (starts_with(name, "refs/"))
1868                 return alloc_ref(name);
1869
1870         if (starts_with(name, "heads/") ||
1871             starts_with(name, "tags/") ||
1872             starts_with(name, "remotes/"))
1873                 return alloc_ref_with_prefix("refs/", 5, name);
1874
1875         return alloc_ref_with_prefix("refs/heads/", 11, name);
1876 }
1877
1878 int get_fetch_map(const struct ref *remote_refs,
1879                   const struct refspec *refspec,
1880                   struct ref ***tail,
1881                   int missing_ok)
1882 {
1883         struct ref *ref_map, **rmp;
1884
1885         if (refspec->pattern) {
1886                 ref_map = get_expanded_map(remote_refs, refspec);
1887         } else {
1888                 const char *name = refspec->src[0] ? refspec->src : "HEAD";
1889
1890                 if (refspec->exact_sha1) {
1891                         ref_map = alloc_ref(name);
1892                         get_oid_hex(name, &ref_map->old_oid);
1893                 } else {
1894                         ref_map = get_remote_ref(remote_refs, name);
1895                 }
1896                 if (!missing_ok && !ref_map)
1897                         die("Couldn't find remote ref %s", name);
1898                 if (ref_map) {
1899                         ref_map->peer_ref = get_local_ref(refspec->dst);
1900                         if (ref_map->peer_ref && refspec->force)
1901                                 ref_map->peer_ref->force = 1;
1902                 }
1903         }
1904
1905         for (rmp = &ref_map; *rmp; ) {
1906                 if ((*rmp)->peer_ref) {
1907                         if (!starts_with((*rmp)->peer_ref->name, "refs/") ||
1908                             check_refname_format((*rmp)->peer_ref->name, 0)) {
1909                                 struct ref *ignore = *rmp;
1910                                 error("* Ignoring funny ref '%s' locally",
1911                                       (*rmp)->peer_ref->name);
1912                                 *rmp = (*rmp)->next;
1913                                 free(ignore->peer_ref);
1914                                 free(ignore);
1915                                 continue;
1916                         }
1917                 }
1918                 rmp = &((*rmp)->next);
1919         }
1920
1921         if (ref_map)
1922                 tail_link_ref(ref_map, tail);
1923
1924         return 0;
1925 }
1926
1927 int resolve_remote_symref(struct ref *ref, struct ref *list)
1928 {
1929         if (!ref->symref)
1930                 return 0;
1931         for (; list; list = list->next)
1932                 if (!strcmp(ref->symref, list->name)) {
1933                         oidcpy(&ref->old_oid, &list->old_oid);
1934                         return 0;
1935                 }
1936         return 1;
1937 }
1938
1939 static void unmark_and_free(struct commit_list *list, unsigned int mark)
1940 {
1941         while (list) {
1942                 struct commit *commit = pop_commit(&list);
1943                 commit->object.flags &= ~mark;
1944         }
1945 }
1946
1947 int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
1948 {
1949         struct object *o;
1950         struct commit *old, *new;
1951         struct commit_list *list, *used;
1952         int found = 0;
1953
1954         /*
1955          * Both new and old must be commit-ish and new is descendant of
1956          * old.  Otherwise we require --force.
1957          */
1958         o = deref_tag(parse_object(old_oid->hash), NULL, 0);
1959         if (!o || o->type != OBJ_COMMIT)
1960                 return 0;
1961         old = (struct commit *) o;
1962
1963         o = deref_tag(parse_object(new_oid->hash), NULL, 0);
1964         if (!o || o->type != OBJ_COMMIT)
1965                 return 0;
1966         new = (struct commit *) o;
1967
1968         if (parse_commit(new) < 0)
1969                 return 0;
1970
1971         used = list = NULL;
1972         commit_list_insert(new, &list);
1973         while (list) {
1974                 new = pop_most_recent_commit(&list, TMP_MARK);
1975                 commit_list_insert(new, &used);
1976                 if (new == old) {
1977                         found = 1;
1978                         break;
1979                 }
1980         }
1981         unmark_and_free(list, TMP_MARK);
1982         unmark_and_free(used, TMP_MARK);
1983         return found;
1984 }
1985
1986 /*
1987  * Compare a branch with its upstream, and save their differences (number
1988  * of commits) in *num_ours and *num_theirs. The name of the upstream branch
1989  * (or NULL if no upstream is defined) is returned via *upstream_name, if it
1990  * is not itself NULL.
1991  *
1992  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
1993  * upstream defined, or ref does not exist), 0 otherwise.
1994  */
1995 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
1996                        const char **upstream_name)
1997 {
1998         struct object_id oid;
1999         struct commit *ours, *theirs;
2000         struct rev_info revs;
2001         const char *base;
2002         struct argv_array argv = ARGV_ARRAY_INIT;
2003
2004         /* Cannot stat unless we are marked to build on top of somebody else. */
2005         base = branch_get_upstream(branch, NULL);
2006         if (upstream_name)
2007                 *upstream_name = base;
2008         if (!base)
2009                 return -1;
2010
2011         /* Cannot stat if what we used to build on no longer exists */
2012         if (read_ref(base, oid.hash))
2013                 return -1;
2014         theirs = lookup_commit_reference(oid.hash);
2015         if (!theirs)
2016                 return -1;
2017
2018         if (read_ref(branch->refname, oid.hash))
2019                 return -1;
2020         ours = lookup_commit_reference(oid.hash);
2021         if (!ours)
2022                 return -1;
2023
2024         /* are we the same? */
2025         if (theirs == ours) {
2026                 *num_theirs = *num_ours = 0;
2027                 return 0;
2028         }
2029
2030         /* Run "rev-list --left-right ours...theirs" internally... */
2031         argv_array_push(&argv, ""); /* ignored */
2032         argv_array_push(&argv, "--left-right");
2033         argv_array_pushf(&argv, "%s...%s",
2034                          oid_to_hex(&ours->object.oid),
2035                          oid_to_hex(&theirs->object.oid));
2036         argv_array_push(&argv, "--");
2037
2038         init_revisions(&revs, NULL);
2039         setup_revisions(argv.argc, argv.argv, &revs, NULL);
2040         if (prepare_revision_walk(&revs))
2041                 die("revision walk setup failed");
2042
2043         /* ... and count the commits on each side. */
2044         *num_ours = 0;
2045         *num_theirs = 0;
2046         while (1) {
2047                 struct commit *c = get_revision(&revs);
2048                 if (!c)
2049                         break;
2050                 if (c->object.flags & SYMMETRIC_LEFT)
2051                         (*num_ours)++;
2052                 else
2053                         (*num_theirs)++;
2054         }
2055
2056         /* clear object flags smudged by the above traversal */
2057         clear_commit_marks(ours, ALL_REV_FLAGS);
2058         clear_commit_marks(theirs, ALL_REV_FLAGS);
2059
2060         argv_array_clear(&argv);
2061         return 0;
2062 }
2063
2064 /*
2065  * Return true when there is anything to report, otherwise false.
2066  */
2067 int format_tracking_info(struct branch *branch, struct strbuf *sb)
2068 {
2069         int ours, theirs;
2070         const char *full_base;
2071         char *base;
2072         int upstream_is_gone = 0;
2073
2074         if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
2075                 if (!full_base)
2076                         return 0;
2077                 upstream_is_gone = 1;
2078         }
2079
2080         base = shorten_unambiguous_ref(full_base, 0);
2081         if (upstream_is_gone) {
2082                 strbuf_addf(sb,
2083                         _("Your branch is based on '%s', but the upstream is gone.\n"),
2084                         base);
2085                 if (advice_status_hints)
2086                         strbuf_addf(sb,
2087                                 _("  (use \"git branch --unset-upstream\" to fixup)\n"));
2088         } else if (!ours && !theirs) {
2089                 strbuf_addf(sb,
2090                         _("Your branch is up-to-date with '%s'.\n"),
2091                         base);
2092         } else if (!theirs) {
2093                 strbuf_addf(sb,
2094                         Q_("Your branch is ahead of '%s' by %d commit.\n",
2095                            "Your branch is ahead of '%s' by %d commits.\n",
2096                            ours),
2097                         base, ours);
2098                 if (advice_status_hints)
2099                         strbuf_addf(sb,
2100                                 _("  (use \"git push\" to publish your local commits)\n"));
2101         } else if (!ours) {
2102                 strbuf_addf(sb,
2103                         Q_("Your branch is behind '%s' by %d commit, "
2104                                "and can be fast-forwarded.\n",
2105                            "Your branch is behind '%s' by %d commits, "
2106                                "and can be fast-forwarded.\n",
2107                            theirs),
2108                         base, theirs);
2109                 if (advice_status_hints)
2110                         strbuf_addf(sb,
2111                                 _("  (use \"git pull\" to update your local branch)\n"));
2112         } else {
2113                 strbuf_addf(sb,
2114                         Q_("Your branch and '%s' have diverged,\n"
2115                                "and have %d and %d different commit each, "
2116                                "respectively.\n",
2117                            "Your branch and '%s' have diverged,\n"
2118                                "and have %d and %d different commits each, "
2119                                "respectively.\n",
2120                            theirs),
2121                         base, ours, theirs);
2122                 if (advice_status_hints)
2123                         strbuf_addf(sb,
2124                                 _("  (use \"git pull\" to merge the remote branch into yours)\n"));
2125         }
2126         free(base);
2127         return 1;
2128 }
2129
2130 static int one_local_ref(const char *refname, const struct object_id *oid,
2131                          int flag, void *cb_data)
2132 {
2133         struct ref ***local_tail = cb_data;
2134         struct ref *ref;
2135         int len;
2136
2137         /* we already know it starts with refs/ to get here */
2138         if (check_refname_format(refname + 5, 0))
2139                 return 0;
2140
2141         len = strlen(refname) + 1;
2142         ref = xcalloc(1, sizeof(*ref) + len);
2143         oidcpy(&ref->new_oid, oid);
2144         memcpy(ref->name, refname, len);
2145         **local_tail = ref;
2146         *local_tail = &ref->next;
2147         return 0;
2148 }
2149
2150 struct ref *get_local_heads(void)
2151 {
2152         struct ref *local_refs = NULL, **local_tail = &local_refs;
2153
2154         for_each_ref(one_local_ref, &local_tail);
2155         return local_refs;
2156 }
2157
2158 struct ref *guess_remote_head(const struct ref *head,
2159                               const struct ref *refs,
2160                               int all)
2161 {
2162         const struct ref *r;
2163         struct ref *list = NULL;
2164         struct ref **tail = &list;
2165
2166         if (!head)
2167                 return NULL;
2168
2169         /*
2170          * Some transports support directly peeking at
2171          * where HEAD points; if that is the case, then
2172          * we don't have to guess.
2173          */
2174         if (head->symref)
2175                 return copy_ref(find_ref_by_name(refs, head->symref));
2176
2177         /* If refs/heads/master could be right, it is. */
2178         if (!all) {
2179                 r = find_ref_by_name(refs, "refs/heads/master");
2180                 if (r && !oidcmp(&r->old_oid, &head->old_oid))
2181                         return copy_ref(r);
2182         }
2183
2184         /* Look for another ref that points there */
2185         for (r = refs; r; r = r->next) {
2186                 if (r != head &&
2187                     starts_with(r->name, "refs/heads/") &&
2188                     !oidcmp(&r->old_oid, &head->old_oid)) {
2189                         *tail = copy_ref(r);
2190                         tail = &((*tail)->next);
2191                         if (!all)
2192                                 break;
2193                 }
2194         }
2195
2196         return list;
2197 }
2198
2199 struct stale_heads_info {
2200         struct string_list *ref_names;
2201         struct ref **stale_refs_tail;
2202         struct refspec *refs;
2203         int ref_count;
2204 };
2205
2206 static int get_stale_heads_cb(const char *refname, const struct object_id *oid,
2207                               int flags, void *cb_data)
2208 {
2209         struct stale_heads_info *info = cb_data;
2210         struct string_list matches = STRING_LIST_INIT_DUP;
2211         struct refspec query;
2212         int i, stale = 1;
2213         memset(&query, 0, sizeof(struct refspec));
2214         query.dst = (char *)refname;
2215
2216         query_refspecs_multiple(info->refs, info->ref_count, &query, &matches);
2217         if (matches.nr == 0)
2218                 goto clean_exit; /* No matches */
2219
2220         /*
2221          * If we did find a suitable refspec and it's not a symref and
2222          * it's not in the list of refs that currently exist in that
2223          * remote, we consider it to be stale. In order to deal with
2224          * overlapping refspecs, we need to go over all of the
2225          * matching refs.
2226          */
2227         if (flags & REF_ISSYMREF)
2228                 goto clean_exit;
2229
2230         for (i = 0; stale && i < matches.nr; i++)
2231                 if (string_list_has_string(info->ref_names, matches.items[i].string))
2232                         stale = 0;
2233
2234         if (stale) {
2235                 struct ref *ref = make_linked_ref(refname, &info->stale_refs_tail);
2236                 oidcpy(&ref->new_oid, oid);
2237         }
2238
2239 clean_exit:
2240         string_list_clear(&matches, 0);
2241         return 0;
2242 }
2243
2244 struct ref *get_stale_heads(struct refspec *refs, int ref_count, struct ref *fetch_map)
2245 {
2246         struct ref *ref, *stale_refs = NULL;
2247         struct string_list ref_names = STRING_LIST_INIT_NODUP;
2248         struct stale_heads_info info;
2249
2250         info.ref_names = &ref_names;
2251         info.stale_refs_tail = &stale_refs;
2252         info.refs = refs;
2253         info.ref_count = ref_count;
2254         for (ref = fetch_map; ref; ref = ref->next)
2255                 string_list_append(&ref_names, ref->name);
2256         string_list_sort(&ref_names);
2257         for_each_ref(get_stale_heads_cb, &info);
2258         string_list_clear(&ref_names, 0);
2259         return stale_refs;
2260 }
2261
2262 /*
2263  * Compare-and-swap
2264  */
2265 static void clear_cas_option(struct push_cas_option *cas)
2266 {
2267         int i;
2268
2269         for (i = 0; i < cas->nr; i++)
2270                 free(cas->entry[i].refname);
2271         free(cas->entry);
2272         memset(cas, 0, sizeof(*cas));
2273 }
2274
2275 static struct push_cas *add_cas_entry(struct push_cas_option *cas,
2276                                       const char *refname,
2277                                       size_t refnamelen)
2278 {
2279         struct push_cas *entry;
2280         ALLOC_GROW(cas->entry, cas->nr + 1, cas->alloc);
2281         entry = &cas->entry[cas->nr++];
2282         memset(entry, 0, sizeof(*entry));
2283         entry->refname = xmemdupz(refname, refnamelen);
2284         return entry;
2285 }
2286
2287 int parse_push_cas_option(struct push_cas_option *cas, const char *arg, int unset)
2288 {
2289         const char *colon;
2290         struct push_cas *entry;
2291
2292         if (unset) {
2293                 /* "--no-<option>" */
2294                 clear_cas_option(cas);
2295                 return 0;
2296         }
2297
2298         if (!arg) {
2299                 /* just "--<option>" */
2300                 cas->use_tracking_for_rest = 1;
2301                 return 0;
2302         }
2303
2304         /* "--<option>=refname" or "--<option>=refname:value" */
2305         colon = strchrnul(arg, ':');
2306         entry = add_cas_entry(cas, arg, colon - arg);
2307         if (!*colon)
2308                 entry->use_tracking = 1;
2309         else if (get_sha1(colon + 1, entry->expect))
2310                 return error("cannot parse expected object name '%s'", colon + 1);
2311         return 0;
2312 }
2313
2314 int parseopt_push_cas_option(const struct option *opt, const char *arg, int unset)
2315 {
2316         return parse_push_cas_option(opt->value, arg, unset);
2317 }
2318
2319 int is_empty_cas(const struct push_cas_option *cas)
2320 {
2321         return !cas->use_tracking_for_rest && !cas->nr;
2322 }
2323
2324 /*
2325  * Look at remote.fetch refspec and see if we have a remote
2326  * tracking branch for the refname there.  Fill its current
2327  * value in sha1[].
2328  * If we cannot do so, return negative to signal an error.
2329  */
2330 static int remote_tracking(struct remote *remote, const char *refname,
2331                            struct object_id *oid)
2332 {
2333         char *dst;
2334
2335         dst = apply_refspecs(remote->fetch, remote->fetch_refspec_nr, refname);
2336         if (!dst)
2337                 return -1; /* no tracking ref for refname at remote */
2338         if (read_ref(dst, oid->hash))
2339                 return -1; /* we know what the tracking ref is but we cannot read it */
2340         return 0;
2341 }
2342
2343 static void apply_cas(struct push_cas_option *cas,
2344                       struct remote *remote,
2345                       struct ref *ref)
2346 {
2347         int i;
2348
2349         /* Find an explicit --<option>=<name>[:<value>] entry */
2350         for (i = 0; i < cas->nr; i++) {
2351                 struct push_cas *entry = &cas->entry[i];
2352                 if (!refname_match(entry->refname, ref->name))
2353                         continue;
2354                 ref->expect_old_sha1 = 1;
2355                 if (!entry->use_tracking)
2356                         hashcpy(ref->old_oid_expect.hash, cas->entry[i].expect);
2357                 else if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2358                         ref->expect_old_no_trackback = 1;
2359                 return;
2360         }
2361
2362         /* Are we using "--<option>" to cover all? */
2363         if (!cas->use_tracking_for_rest)
2364                 return;
2365
2366         ref->expect_old_sha1 = 1;
2367         if (remote_tracking(remote, ref->name, &ref->old_oid_expect))
2368                 ref->expect_old_no_trackback = 1;
2369 }
2370
2371 void apply_push_cas(struct push_cas_option *cas,
2372                     struct remote *remote,
2373                     struct ref *remote_refs)
2374 {
2375         struct ref *ref;
2376         for (ref = remote_refs; ref; ref = ref->next)
2377                 apply_cas(cas, remote, ref);
2378 }