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

   1 #include "cache.h"
   2 #include "config.h"
   3 #include "builtin.h"
   4 #include "exec-cmd.h"
   5 #include "run-command.h"
   6 #include "levenshtein.h"
   7 #include "help.h"
   8 #include "command-list.h"
   9 #include "string-list.h"
  10 #include "column.h"
  11 #include "version.h"
  12 #include "refs.h"
  13 #include "parse-options.h"
  14
  15 struct category_description {
  16         uint32_t category;
  17         const char *desc;
  18 };
  19 static uint32_t common_mask =
  20         CAT_init | CAT_worktree | CAT_info |
  21         CAT_history | CAT_remote;
  22 static struct category_description common_categories[] = {
  23         { CAT_init, N_("start a working area (see also: git help tutorial)") },
  24         { CAT_worktree, N_("work on the current change (see also: git help everyday)") },
  25         { CAT_info, N_("examine the history and state (see also: git help revisions)") },
  26         { CAT_history, N_("grow, mark and tweak your common history") },
  27         { CAT_remote, N_("collaborate (see also: git help workflows)") },
  28         { 0, NULL }
  29 };
  30 static struct category_description main_categories[] = {
  31         { CAT_mainporcelain, N_("Main Porcelain Commands") },
  32         { CAT_ancillarymanipulators, N_("Ancillary Commands / Manipulators") },
  33         { CAT_ancillaryinterrogators, N_("Ancillary Commands / Interrogators") },
  34         { CAT_foreignscminterface, N_("Interacting with Others") },
  35         { CAT_plumbingmanipulators, N_("Low-level Commands / Manipulators") },
  36         { CAT_plumbinginterrogators, N_("Low-level Commands / Interrogators") },
  37         { CAT_synchingrepositories, N_("Low-level Commands / Syncing Repositories") },
  38         { CAT_purehelpers, N_("Low-level Commands / Internal Helpers") },
  39         { 0, NULL }
  40 };
  41
  42 static const char *drop_prefix(const char *name, uint32_t category)
  43 {
  44         const char *new_name;
  45
  46         if (skip_prefix(name, "git-", &new_name))
  47                 return new_name;
  48         if (category == CAT_guide && skip_prefix(name, "git", &new_name))
  49                 return new_name;
  50         return name;
  51
  52 }
  53
  54 static void extract_cmds(struct cmdname_help **p_cmds, uint32_t mask)
  55 {
  56         int i, nr = 0;
  57         struct cmdname_help *cmds;
  58
  59         if (ARRAY_SIZE(command_list) == 0)
  60                 BUG("empty command_list[] is a sign of broken generate-cmdlist.sh");
  61
  62         ALLOC_ARRAY(cmds, ARRAY_SIZE(command_list) + 1);
  63
  64         for (i = 0; i < ARRAY_SIZE(command_list); i++) {
  65                 const struct cmdname_help *cmd = command_list + i;
  66
  67                 if (!(cmd->category & mask))
  68                         continue;
  69
  70                 cmds[nr] = *cmd;
  71                 cmds[nr].name = drop_prefix(cmd->name, cmd->category);
  72
  73                 nr++;
  74         }
  75         cmds[nr].name = NULL;
  76         *p_cmds = cmds;
  77 }
  78
  79 static void print_command_list(const struct cmdname_help *cmds,
  80                                uint32_t mask, int longest)
  81 {
  82         int i;
  83
  84         for (i = 0; cmds[i].name; i++) {
  85                 if (cmds[i].category & mask) {
  86                         size_t len = strlen(cmds[i].name);
  87                         printf("   %s   ", cmds[i].name);
  88                         if (longest > len)
  89                                 mput_char(' ', longest - len);
  90                         puts(_(cmds[i].help));
  91                 }
  92         }
  93 }
  94
  95 static int cmd_name_cmp(const void *elem1, const void *elem2)
  96 {
  97         const struct cmdname_help *e1 = elem1;
  98         const struct cmdname_help *e2 = elem2;
  99
 100         return strcmp(e1->name, e2->name);
 101 }
 102
 103 static void print_cmd_by_category(const struct category_description *catdesc,
 104                                   int *longest_p)
 105 {
 106         struct cmdname_help *cmds;
 107         int longest = 0;
 108         int i, nr = 0;
 109         uint32_t mask = 0;
 110
 111         for (i = 0; catdesc[i].desc; i++)
 112                 mask |= catdesc[i].category;
 113
 114         extract_cmds(&cmds, mask);
 115
 116         for (i = 0; cmds[i].name; i++, nr++) {
 117                 if (longest < strlen(cmds[i].name))
 118                         longest = strlen(cmds[i].name);
 119         }
 120         QSORT(cmds, nr, cmd_name_cmp);
 121
 122         for (i = 0; catdesc[i].desc; i++) {
 123                 uint32_t mask = catdesc[i].category;
 124                 const char *desc = catdesc[i].desc;
 125
 126                 printf("\n%s\n", _(desc));
 127                 print_command_list(cmds, mask, longest);
 128         }
 129         free(cmds);
 130         if (longest_p)
 131                 *longest_p = longest;
 132 }
 133
 134 void add_cmdname(struct cmdnames *cmds, const char *name, int len)
 135 {
 136         struct cmdname *ent;
 137         FLEX_ALLOC_MEM(ent, name, name, len);
 138         ent->len = len;
 139
 140         ALLOC_GROW(cmds->names, cmds->cnt + 1, cmds->alloc);
 141         cmds->names[cmds->cnt++] = ent;
 142 }
 143
 144 static void clean_cmdnames(struct cmdnames *cmds)
 145 {
 146         int i;
 147         for (i = 0; i < cmds->cnt; ++i)
 148                 free(cmds->names[i]);
 149         free(cmds->names);
 150         cmds->cnt = 0;
 151         cmds->alloc = 0;
 152 }
 153
 154 static int cmdname_compare(const void *a_, const void *b_)
 155 {
 156         struct cmdname *a = *(struct cmdname **)a_;
 157         struct cmdname *b = *(struct cmdname **)b_;
 158         return strcmp(a->name, b->name);
 159 }
 160
 161 static void uniq(struct cmdnames *cmds)
 162 {
 163         int i, j;
 164
 165         if (!cmds->cnt)
 166                 return;
 167
 168         for (i = j = 1; i < cmds->cnt; i++) {
 169                 if (!strcmp(cmds->names[i]->name, cmds->names[j-1]->name))
 170                         free(cmds->names[i]);
 171                 else
 172                         cmds->names[j++] = cmds->names[i];
 173         }
 174
 175         cmds->cnt = j;
 176 }
 177
 178 void exclude_cmds(struct cmdnames *cmds, struct cmdnames *excludes)
 179 {
 180         int ci, cj, ei;
 181         int cmp;
 182
 183         ci = cj = ei = 0;
 184         while (ci < cmds->cnt && ei < excludes->cnt) {
 185                 cmp = strcmp(cmds->names[ci]->name, excludes->names[ei]->name);
 186                 if (cmp < 0)
 187                         cmds->names[cj++] = cmds->names[ci++];
 188                 else if (cmp == 0) {
 189                         ei++;
 190                         free(cmds->names[ci++]);
 191                 } else if (cmp > 0)
 192                         ei++;
 193         }
 194
 195         while (ci < cmds->cnt)
 196                 cmds->names[cj++] = cmds->names[ci++];
 197
 198         cmds->cnt = cj;
 199 }
 200
 201 static void pretty_print_cmdnames(struct cmdnames *cmds, unsigned int colopts)
 202 {
 203         struct string_list list = STRING_LIST_INIT_NODUP;
 204         struct column_options copts;
 205         int i;
 206
 207         for (i = 0; i < cmds->cnt; i++)
 208                 string_list_append(&list, cmds->names[i]->name);
 209         /*
 210          * always enable column display, we only consult column.*
 211          * about layout strategy and stuff
 212          */
 213         colopts = (colopts & ~COL_ENABLE_MASK) | COL_ENABLED;
 214         memset(&copts, 0, sizeof(copts));
 215         copts.indent = "  ";
 216         copts.padding = 2;
 217         print_columns(&list, colopts, &copts);
 218         string_list_clear(&list, 0);
 219 }
 220
 221 static void list_commands_in_dir(struct cmdnames *cmds,
 222                                          const char *path,
 223                                          const char *prefix)
 224 {
 225         DIR *dir = opendir(path);
 226         struct dirent *de;
 227         struct strbuf buf = STRBUF_INIT;
 228         int len;
 229
 230         if (!dir)
 231                 return;
 232         if (!prefix)
 233                 prefix = "git-";
 234
 235         strbuf_addf(&buf, "%s/", path);
 236         len = buf.len;
 237
 238         while ((de = readdir(dir)) != NULL) {
 239                 const char *ent;
 240                 size_t entlen;
 241
 242                 if (!skip_prefix(de->d_name, prefix, &ent))
 243                         continue;
 244
 245                 strbuf_setlen(&buf, len);
 246                 strbuf_addstr(&buf, de->d_name);
 247                 if (!is_executable(buf.buf))
 248                         continue;
 249
 250                 entlen = strlen(ent);
 251                 strip_suffix(ent, ".exe", &entlen);
 252
 253                 add_cmdname(cmds, ent, entlen);
 254         }
 255         closedir(dir);
 256         strbuf_release(&buf);
 257 }
 258
 259 void load_command_list(const char *prefix,
 260                 struct cmdnames *main_cmds,
 261                 struct cmdnames *other_cmds)
 262 {
 263         const char *env_path = getenv("PATH");
 264         const char *exec_path = git_exec_path();
 265
 266         if (exec_path) {
 267                 list_commands_in_dir(main_cmds, exec_path, prefix);
 268                 QSORT(main_cmds->names, main_cmds->cnt, cmdname_compare);
 269                 uniq(main_cmds);
 270         }
 271
 272         if (env_path) {
 273                 char *paths, *path, *colon;
 274                 path = paths = xstrdup(env_path);
 275                 while (1) {
 276                         if ((colon = strchr(path, PATH_SEP)))
 277                                 *colon = 0;
 278                         if (!exec_path || strcmp(path, exec_path))
 279                                 list_commands_in_dir(other_cmds, path, prefix);
 280
 281                         if (!colon)
 282                                 break;
 283                         path = colon + 1;
 284                 }
 285                 free(paths);
 286
 287                 QSORT(other_cmds->names, other_cmds->cnt, cmdname_compare);
 288                 uniq(other_cmds);
 289         }
 290         exclude_cmds(other_cmds, main_cmds);
 291 }
 292
 293 void list_commands(unsigned int colopts,
 294                    struct cmdnames *main_cmds, struct cmdnames *other_cmds)
 295 {
 296         if (main_cmds->cnt) {
 297                 const char *exec_path = git_exec_path();
 298                 printf_ln(_("available git commands in '%s'"), exec_path);
 299                 putchar('\n');
 300                 pretty_print_cmdnames(main_cmds, colopts);
 301                 putchar('\n');
 302         }
 303
 304         if (other_cmds->cnt) {
 305                 printf_ln(_("git commands available from elsewhere on your $PATH"));
 306                 putchar('\n');
 307                 pretty_print_cmdnames(other_cmds, colopts);
 308                 putchar('\n');
 309         }
 310 }
 311
 312 void list_common_cmds_help(void)
 313 {
 314         puts(_("These are common Git commands used in various situations:"));
 315         print_cmd_by_category(common_categories, NULL);
 316 }
 317
 318 void list_all_main_cmds(struct string_list *list)
 319 {
 320         struct cmdnames main_cmds, other_cmds;
 321         int i;
 322
 323         memset(&main_cmds, 0, sizeof(main_cmds));
 324         memset(&other_cmds, 0, sizeof(other_cmds));
 325         load_command_list("git-", &main_cmds, &other_cmds);
 326
 327         for (i = 0; i < main_cmds.cnt; i++)
 328                 string_list_append(list, main_cmds.names[i]->name);
 329
 330         clean_cmdnames(&main_cmds);
 331         clean_cmdnames(&other_cmds);
 332 }
 333
 334 void list_all_other_cmds(struct string_list *list)
 335 {
 336         struct cmdnames main_cmds, other_cmds;
 337         int i;
 338
 339         memset(&main_cmds, 0, sizeof(main_cmds));
 340         memset(&other_cmds, 0, sizeof(other_cmds));
 341         load_command_list("git-", &main_cmds, &other_cmds);
 342
 343         for (i = 0; i < other_cmds.cnt; i++)
 344                 string_list_append(list, other_cmds.names[i]->name);
 345
 346         clean_cmdnames(&main_cmds);
 347         clean_cmdnames(&other_cmds);
 348 }
 349
 350 void list_cmds_by_category(struct string_list *list,
 351                            const char *cat)
 352 {
 353         int i, n = ARRAY_SIZE(command_list);
 354         uint32_t cat_id = 0;
 355
 356         for (i = 0; category_names[i]; i++) {
 357                 if (!strcmp(cat, category_names[i])) {
 358                         cat_id = 1UL << i;
 359                         break;
 360                 }
 361         }
 362         if (!cat_id)
 363                 die(_("unsupported command listing type '%s'"), cat);
 364
 365         for (i = 0; i < n; i++) {
 366                 struct cmdname_help *cmd = command_list + i;
 367
 368                 if (!(cmd->category & cat_id))
 369                         continue;
 370                 string_list_append(list, drop_prefix(cmd->name, cmd->category));
 371         }
 372 }
 373
 374 void list_cmds_by_config(struct string_list *list)
 375 {
 376         const char *cmd_list;
 377
 378         if (git_config_get_string_tmp("completion.commands", &cmd_list))
 379                 return;
 380
 381         string_list_sort(list);
 382         string_list_remove_duplicates(list, 0);
 383
 384         while (*cmd_list) {
 385                 struct strbuf sb = STRBUF_INIT;
 386                 const char *p = strchrnul(cmd_list, ' ');
 387
 388                 strbuf_add(&sb, cmd_list, p - cmd_list);
 389                 if (sb.buf[0] == '-')
 390                         string_list_remove(list, sb.buf + 1, 0);
 391                 else
 392                         string_list_insert(list, sb.buf);
 393                 strbuf_release(&sb);
 394                 while (*p == ' ')
 395                         p++;
 396                 cmd_list = p;
 397         }
 398 }
 399
 400 void list_guides_help(void)
 401 {
 402         struct category_description catdesc[] = {
 403                 { CAT_guide, N_("The Git concept guides are:") },
 404                 { 0, NULL }
 405         };
 406         print_cmd_by_category(catdesc, NULL);
 407         putchar('\n');
 408 }
 409
 410 static int get_alias(const char *var, const char *value, void *data)
 411 {
 412         struct string_list *list = data;
 413
 414         if (skip_prefix(var, "alias.", &var))
 415                 string_list_append(list, var)->util = xstrdup(value);
 416
 417         return 0;
 418 }
 419
 420 void list_all_cmds_help(void)
 421 {
 422         struct string_list others = STRING_LIST_INIT_DUP;
 423         struct string_list alias_list = STRING_LIST_INIT_DUP;
 424         struct cmdname_help *aliases;
 425         int i, longest;
 426
 427         printf_ln(_("See 'git help <command>' to read about a specific subcommand"));
 428         print_cmd_by_category(main_categories, &longest);
 429
 430         list_all_other_cmds(&others);
 431         if (others.nr)
 432                 printf("\n%s\n", _("External commands"));
 433         for (i = 0; i < others.nr; i++)
 434                 printf("   %s\n", others.items[i].string);
 435         string_list_clear(&others, 0);
 436
 437         git_config(get_alias, &alias_list);
 438         string_list_sort(&alias_list);
 439
 440         for (i = 0; i < alias_list.nr; i++) {
 441                 size_t len = strlen(alias_list.items[i].string);
 442                 if (longest < len)
 443                         longest = len;
 444         }
 445
 446         if (alias_list.nr) {
 447                 printf("\n%s\n", _("Command aliases"));
 448                 ALLOC_ARRAY(aliases, alias_list.nr + 1);
 449                 for (i = 0; i < alias_list.nr; i++) {
 450                         aliases[i].name = alias_list.items[i].string;
 451                         aliases[i].help = alias_list.items[i].util;
 452                         aliases[i].category = 1;
 453                 }
 454                 aliases[alias_list.nr].name = NULL;
 455                 print_command_list(aliases, 1, longest);
 456                 free(aliases);
 457         }
 458         string_list_clear(&alias_list, 1);
 459 }
 460
 461 int is_in_cmdlist(struct cmdnames *c, const char *s)
 462 {
 463         int i;
 464         for (i = 0; i < c->cnt; i++)
 465                 if (!strcmp(s, c->names[i]->name))
 466                         return 1;
 467         return 0;
 468 }
 469
 470 static int autocorrect;
 471 static struct cmdnames aliases;
 472
 473 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
 474 {
 475         const char *p;
 476
 477         if (!strcmp(var, "help.autocorrect"))
 478                 autocorrect = git_config_int(var,value);
 479         /* Also use aliases for command lookup */
 480         if (skip_prefix(var, "alias.", &p))
 481                 add_cmdname(&aliases, p, strlen(p));
 482
 483         return git_default_config(var, value, cb);
 484 }
 485
 486 static int levenshtein_compare(const void *p1, const void *p2)
 487 {
 488         const struct cmdname *const *c1 = p1, *const *c2 = p2;
 489         const char *s1 = (*c1)->name, *s2 = (*c2)->name;
 490         int l1 = (*c1)->len;
 491         int l2 = (*c2)->len;
 492         return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
 493 }
 494
 495 static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
 496 {
 497         int i;
 498         ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
 499
 500         for (i = 0; i < old->cnt; i++)
 501                 cmds->names[cmds->cnt++] = old->names[i];
 502         FREE_AND_NULL(old->names);
 503         old->cnt = 0;
 504 }
 505
 506 /* An empirically derived magic number */
 507 #define SIMILARITY_FLOOR 7
 508 #define SIMILAR_ENOUGH(x) ((x) < SIMILARITY_FLOOR)
 509
 510 static const char bad_interpreter_advice[] =
 511         N_("'%s' appears to be a git command, but we were not\n"
 512         "able to execute it. Maybe git-%s is broken?");
 513
 514 const char *help_unknown_cmd(const char *cmd)
 515 {
 516         int i, n, best_similarity = 0;
 517         struct cmdnames main_cmds, other_cmds;
 518         struct cmdname_help *common_cmds;
 519
 520         memset(&main_cmds, 0, sizeof(main_cmds));
 521         memset(&other_cmds, 0, sizeof(other_cmds));
 522         memset(&aliases, 0, sizeof(aliases));
 523
 524         read_early_config(git_unknown_cmd_config, NULL);
 525
 526         load_command_list("git-", &main_cmds, &other_cmds);
 527
 528         add_cmd_list(&main_cmds, &aliases);
 529         add_cmd_list(&main_cmds, &other_cmds);
 530         QSORT(main_cmds.names, main_cmds.cnt, cmdname_compare);
 531         uniq(&main_cmds);
 532
 533         extract_cmds(&common_cmds, common_mask);
 534
 535         /* This abuses cmdname->len for levenshtein distance */
 536         for (i = 0, n = 0; i < main_cmds.cnt; i++) {
 537                 int cmp = 0; /* avoid compiler stupidity */
 538                 const char *candidate = main_cmds.names[i]->name;
 539
 540                 /*
 541                  * An exact match means we have the command, but
 542                  * for some reason exec'ing it gave us ENOENT; probably
 543                  * it's a bad interpreter in the #! line.
 544                  */
 545                 if (!strcmp(candidate, cmd))
 546                         die(_(bad_interpreter_advice), cmd, cmd);
 547
 548                 /* Does the candidate appear in common_cmds list? */
 549                 while (common_cmds[n].name &&
 550                        (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
 551                         n++;
 552                 if (common_cmds[n].name && !cmp) {
 553                         /* Yes, this is one of the common commands */
 554                         n++; /* use the entry from common_cmds[] */
 555                         if (starts_with(candidate, cmd)) {
 556                                 /* Give prefix match a very good score */
 557                                 main_cmds.names[i]->len = 0;
 558                                 continue;
 559                         }
 560                 }
 561
 562                 main_cmds.names[i]->len =
 563                         levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
 564         }
 565         FREE_AND_NULL(common_cmds);
 566
 567         QSORT(main_cmds.names, main_cmds.cnt, levenshtein_compare);
 568
 569         if (!main_cmds.cnt)
 570                 die(_("Uh oh. Your system reports no Git commands at all."));
 571
 572         /* skip and count prefix matches */
 573         for (n = 0; n < main_cmds.cnt && !main_cmds.names[n]->len; n++)
 574                 ; /* still counting */
 575
 576         if (main_cmds.cnt <= n) {
 577                 /* prefix matches with everything? that is too ambiguous */
 578                 best_similarity = SIMILARITY_FLOOR + 1;
 579         } else {
 580                 /* count all the most similar ones */
 581                 for (best_similarity = main_cmds.names[n++]->len;
 582                      (n < main_cmds.cnt &&
 583                       best_similarity == main_cmds.names[n]->len);
 584                      n++)
 585                         ; /* still counting */
 586         }
 587         if (autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {
 588                 const char *assumed = main_cmds.names[0]->name;
 589                 main_cmds.names[0] = NULL;
 590                 clean_cmdnames(&main_cmds);
 591                 fprintf_ln(stderr,
 592                            _("WARNING: You called a Git command named '%s', "
 593                              "which does not exist."),
 594                            cmd);
 595                 if (autocorrect < 0)
 596                         fprintf_ln(stderr,
 597                                    _("Continuing under the assumption that "
 598                                      "you meant '%s'."),
 599                                    assumed);
 600                 else {
 601                         fprintf_ln(stderr,
 602                                    _("Continuing in %0.1f seconds, "
 603                                      "assuming that you meant '%s'."),
 604                                    (float)autocorrect/10.0, assumed);
 605                         sleep_millisec(autocorrect * 100);
 606                 }
 607                 return assumed;
 608         }
 609
 610         fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
 611
 612         if (SIMILAR_ENOUGH(best_similarity)) {
 613                 fprintf_ln(stderr,
 614                            Q_("\nThe most similar command is",
 615                               "\nThe most similar commands are",
 616                            n));
 617
 618                 for (i = 0; i < n; i++)
 619                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
 620         }
 621
 622         exit(1);
 623 }
 624
 625 void get_version_info(struct strbuf *buf, int show_build_options)
 626 {
 627         /*
 628          * The format of this string should be kept stable for compatibility
 629          * with external projects that rely on the output of "git version".
 630          *
 631          * Always show the version, even if other options are given.
 632          */
 633         strbuf_addf(buf, "git version %s\n", git_version_string);
 634
 635         if (show_build_options) {
 636                 strbuf_addf(buf, "cpu: %s\n", GIT_HOST_CPU);
 637                 if (git_built_from_commit_string[0])
 638                         strbuf_addf(buf, "built from commit: %s\n",
 639                                git_built_from_commit_string);
 640                 else
 641                         strbuf_addstr(buf, "no commit associated with this build\n");
 642                 strbuf_addf(buf, "sizeof-long: %d\n", (int)sizeof(long));
 643                 strbuf_addf(buf, "sizeof-size_t: %d\n", (int)sizeof(size_t));
 644                 strbuf_addf(buf, "shell-path: %s\n", SHELL_PATH);
 645                 /* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
 646         }
 647 }
 648
 649 int cmd_version(int argc, const char **argv, const char *prefix)
 650 {
 651         struct strbuf buf = STRBUF_INIT;
 652         int build_options = 0;
 653         const char * const usage[] = {
 654                 N_("git version [<options>]"),
 655                 NULL
 656         };
 657         struct option options[] = {
 658                 OPT_BOOL(0, "build-options", &build_options,
 659                          "also print build options"),
 660                 OPT_END()
 661         };
 662
 663         argc = parse_options(argc, argv, prefix, options, usage, 0);
 664
 665         get_version_info(&buf, build_options);
 666         printf("%s", buf.buf);
 667
 668         strbuf_release(&buf);
 669
 670         return 0;
 671 }
 672
 673 struct similar_ref_cb {
 674         const char *base_ref;
 675         struct string_list *similar_refs;
 676 };
 677
 678 static int append_similar_ref(const char *refname, const struct object_id *oid,
 679                               int flags, void *cb_data)
 680 {
 681         struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
 682         char *branch = strrchr(refname, '/') + 1;
 683
 684         /* A remote branch of the same name is deemed similar */
 685         if (starts_with(refname, "refs/remotes/") &&
 686             !strcmp(branch, cb->base_ref))
 687                 string_list_append_nodup(cb->similar_refs,
 688                                          shorten_unambiguous_ref(refname, 1));
 689         return 0;
 690 }
 691
 692 static struct string_list guess_refs(const char *ref)
 693 {
 694         struct similar_ref_cb ref_cb;
 695         struct string_list similar_refs = STRING_LIST_INIT_DUP;
 696
 697         ref_cb.base_ref = ref;
 698         ref_cb.similar_refs = &similar_refs;
 699         for_each_ref(append_similar_ref, &ref_cb);
 700         return similar_refs;
 701 }
 702
 703 NORETURN void help_unknown_ref(const char *ref, const char *cmd,
 704                                const char *error)
 705 {
 706         int i;
 707         struct string_list suggested_refs = guess_refs(ref);
 708
 709         fprintf_ln(stderr, _("%s: %s - %s"), cmd, ref, error);
 710
 711         if (suggested_refs.nr > 0) {
 712                 fprintf_ln(stderr,
 713                            Q_("\nDid you mean this?",
 714                               "\nDid you mean one of these?",
 715                               suggested_refs.nr));
 716                 for (i = 0; i < suggested_refs.nr; i++)
 717                         fprintf(stderr, "\t%s\n", suggested_refs.items[i].string);
 718         }
 719
 720         string_list_clear(&suggested_refs, 0);
 721         exit(1);
 722 }