mailmap tests: remove redundant entry in test
[git] / 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         load_builtin_commands(prefix, main_cmds);
267
268         if (exec_path) {
269                 list_commands_in_dir(main_cmds, exec_path, prefix);
270                 QSORT(main_cmds->names, main_cmds->cnt, cmdname_compare);
271                 uniq(main_cmds);
272         }
273
274         if (env_path) {
275                 char *paths, *path, *colon;
276                 path = paths = xstrdup(env_path);
277                 while (1) {
278                         if ((colon = strchr(path, PATH_SEP)))
279                                 *colon = 0;
280                         if (!exec_path || strcmp(path, exec_path))
281                                 list_commands_in_dir(other_cmds, path, prefix);
282
283                         if (!colon)
284                                 break;
285                         path = colon + 1;
286                 }
287                 free(paths);
288
289                 QSORT(other_cmds->names, other_cmds->cnt, cmdname_compare);
290                 uniq(other_cmds);
291         }
292         exclude_cmds(other_cmds, main_cmds);
293 }
294
295 void list_commands(unsigned int colopts,
296                    struct cmdnames *main_cmds, struct cmdnames *other_cmds)
297 {
298         if (main_cmds->cnt) {
299                 const char *exec_path = git_exec_path();
300                 printf_ln(_("available git commands in '%s'"), exec_path);
301                 putchar('\n');
302                 pretty_print_cmdnames(main_cmds, colopts);
303                 putchar('\n');
304         }
305
306         if (other_cmds->cnt) {
307                 printf_ln(_("git commands available from elsewhere on your $PATH"));
308                 putchar('\n');
309                 pretty_print_cmdnames(other_cmds, colopts);
310                 putchar('\n');
311         }
312 }
313
314 void list_common_cmds_help(void)
315 {
316         puts(_("These are common Git commands used in various situations:"));
317         print_cmd_by_category(common_categories, NULL);
318 }
319
320 void list_all_main_cmds(struct string_list *list)
321 {
322         struct cmdnames main_cmds, other_cmds;
323         int i;
324
325         memset(&main_cmds, 0, sizeof(main_cmds));
326         memset(&other_cmds, 0, sizeof(other_cmds));
327         load_command_list("git-", &main_cmds, &other_cmds);
328
329         for (i = 0; i < main_cmds.cnt; i++)
330                 string_list_append(list, main_cmds.names[i]->name);
331
332         clean_cmdnames(&main_cmds);
333         clean_cmdnames(&other_cmds);
334 }
335
336 void list_all_other_cmds(struct string_list *list)
337 {
338         struct cmdnames main_cmds, other_cmds;
339         int i;
340
341         memset(&main_cmds, 0, sizeof(main_cmds));
342         memset(&other_cmds, 0, sizeof(other_cmds));
343         load_command_list("git-", &main_cmds, &other_cmds);
344
345         for (i = 0; i < other_cmds.cnt; i++)
346                 string_list_append(list, other_cmds.names[i]->name);
347
348         clean_cmdnames(&main_cmds);
349         clean_cmdnames(&other_cmds);
350 }
351
352 void list_cmds_by_category(struct string_list *list,
353                            const char *cat)
354 {
355         int i, n = ARRAY_SIZE(command_list);
356         uint32_t cat_id = 0;
357
358         for (i = 0; category_names[i]; i++) {
359                 if (!strcmp(cat, category_names[i])) {
360                         cat_id = 1UL << i;
361                         break;
362                 }
363         }
364         if (!cat_id)
365                 die(_("unsupported command listing type '%s'"), cat);
366
367         for (i = 0; i < n; i++) {
368                 struct cmdname_help *cmd = command_list + i;
369
370                 if (!(cmd->category & cat_id))
371                         continue;
372                 string_list_append(list, drop_prefix(cmd->name, cmd->category));
373         }
374 }
375
376 void list_cmds_by_config(struct string_list *list)
377 {
378         const char *cmd_list;
379
380         if (git_config_get_string_tmp("completion.commands", &cmd_list))
381                 return;
382
383         string_list_sort(list);
384         string_list_remove_duplicates(list, 0);
385
386         while (*cmd_list) {
387                 struct strbuf sb = STRBUF_INIT;
388                 const char *p = strchrnul(cmd_list, ' ');
389
390                 strbuf_add(&sb, cmd_list, p - cmd_list);
391                 if (sb.buf[0] == '-')
392                         string_list_remove(list, sb.buf + 1, 0);
393                 else
394                         string_list_insert(list, sb.buf);
395                 strbuf_release(&sb);
396                 while (*p == ' ')
397                         p++;
398                 cmd_list = p;
399         }
400 }
401
402 void list_guides_help(void)
403 {
404         struct category_description catdesc[] = {
405                 { CAT_guide, N_("The Git concept guides are:") },
406                 { 0, NULL }
407         };
408         print_cmd_by_category(catdesc, NULL);
409         putchar('\n');
410 }
411
412 static int get_alias(const char *var, const char *value, void *data)
413 {
414         struct string_list *list = data;
415
416         if (skip_prefix(var, "alias.", &var))
417                 string_list_append(list, var)->util = xstrdup(value);
418
419         return 0;
420 }
421
422 void list_all_cmds_help(void)
423 {
424         struct string_list others = STRING_LIST_INIT_DUP;
425         struct string_list alias_list = STRING_LIST_INIT_DUP;
426         struct cmdname_help *aliases;
427         int i, longest;
428
429         printf_ln(_("See 'git help <command>' to read about a specific subcommand"));
430         print_cmd_by_category(main_categories, &longest);
431
432         list_all_other_cmds(&others);
433         if (others.nr)
434                 printf("\n%s\n", _("External commands"));
435         for (i = 0; i < others.nr; i++)
436                 printf("   %s\n", others.items[i].string);
437         string_list_clear(&others, 0);
438
439         git_config(get_alias, &alias_list);
440         string_list_sort(&alias_list);
441
442         for (i = 0; i < alias_list.nr; i++) {
443                 size_t len = strlen(alias_list.items[i].string);
444                 if (longest < len)
445                         longest = len;
446         }
447
448         if (alias_list.nr) {
449                 printf("\n%s\n", _("Command aliases"));
450                 ALLOC_ARRAY(aliases, alias_list.nr + 1);
451                 for (i = 0; i < alias_list.nr; i++) {
452                         aliases[i].name = alias_list.items[i].string;
453                         aliases[i].help = alias_list.items[i].util;
454                         aliases[i].category = 1;
455                 }
456                 aliases[alias_list.nr].name = NULL;
457                 print_command_list(aliases, 1, longest);
458                 free(aliases);
459         }
460         string_list_clear(&alias_list, 1);
461 }
462
463 int is_in_cmdlist(struct cmdnames *c, const char *s)
464 {
465         int i;
466         for (i = 0; i < c->cnt; i++)
467                 if (!strcmp(s, c->names[i]->name))
468                         return 1;
469         return 0;
470 }
471
472 static int autocorrect;
473 static struct cmdnames aliases;
474
475 #define AUTOCORRECT_NEVER (-2)
476 #define AUTOCORRECT_IMMEDIATELY (-1)
477
478 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
479 {
480         const char *p;
481
482         if (!strcmp(var, "help.autocorrect")) {
483                 if (!value)
484                         return config_error_nonbool(var);
485                 if (!strcmp(value, "never")) {
486                         autocorrect = AUTOCORRECT_NEVER;
487                 } else if (!strcmp(value, "immediate")) {
488                         autocorrect = AUTOCORRECT_IMMEDIATELY;
489                 } else {
490                         int v = git_config_int(var, value);
491                         autocorrect = (v < 0)
492                                 ? AUTOCORRECT_IMMEDIATELY : v;
493                 }
494         }
495         /* Also use aliases for command lookup */
496         if (skip_prefix(var, "alias.", &p))
497                 add_cmdname(&aliases, p, strlen(p));
498
499         return git_default_config(var, value, cb);
500 }
501
502 static int levenshtein_compare(const void *p1, const void *p2)
503 {
504         const struct cmdname *const *c1 = p1, *const *c2 = p2;
505         const char *s1 = (*c1)->name, *s2 = (*c2)->name;
506         int l1 = (*c1)->len;
507         int l2 = (*c2)->len;
508         return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
509 }
510
511 static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
512 {
513         int i;
514         ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
515
516         for (i = 0; i < old->cnt; i++)
517                 cmds->names[cmds->cnt++] = old->names[i];
518         FREE_AND_NULL(old->names);
519         old->cnt = 0;
520 }
521
522 /* An empirically derived magic number */
523 #define SIMILARITY_FLOOR 7
524 #define SIMILAR_ENOUGH(x) ((x) < SIMILARITY_FLOOR)
525
526 static const char bad_interpreter_advice[] =
527         N_("'%s' appears to be a git command, but we were not\n"
528         "able to execute it. Maybe git-%s is broken?");
529
530 const char *help_unknown_cmd(const char *cmd)
531 {
532         int i, n, best_similarity = 0;
533         struct cmdnames main_cmds, other_cmds;
534         struct cmdname_help *common_cmds;
535
536         memset(&main_cmds, 0, sizeof(main_cmds));
537         memset(&other_cmds, 0, sizeof(other_cmds));
538         memset(&aliases, 0, sizeof(aliases));
539
540         read_early_config(git_unknown_cmd_config, NULL);
541
542         if (autocorrect == AUTOCORRECT_NEVER) {
543                 fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
544                 exit(1);
545         }
546
547         load_command_list("git-", &main_cmds, &other_cmds);
548
549         add_cmd_list(&main_cmds, &aliases);
550         add_cmd_list(&main_cmds, &other_cmds);
551         QSORT(main_cmds.names, main_cmds.cnt, cmdname_compare);
552         uniq(&main_cmds);
553
554         extract_cmds(&common_cmds, common_mask);
555
556         /* This abuses cmdname->len for levenshtein distance */
557         for (i = 0, n = 0; i < main_cmds.cnt; i++) {
558                 int cmp = 0; /* avoid compiler stupidity */
559                 const char *candidate = main_cmds.names[i]->name;
560
561                 /*
562                  * An exact match means we have the command, but
563                  * for some reason exec'ing it gave us ENOENT; probably
564                  * it's a bad interpreter in the #! line.
565                  */
566                 if (!strcmp(candidate, cmd))
567                         die(_(bad_interpreter_advice), cmd, cmd);
568
569                 /* Does the candidate appear in common_cmds list? */
570                 while (common_cmds[n].name &&
571                        (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
572                         n++;
573                 if (common_cmds[n].name && !cmp) {
574                         /* Yes, this is one of the common commands */
575                         n++; /* use the entry from common_cmds[] */
576                         if (starts_with(candidate, cmd)) {
577                                 /* Give prefix match a very good score */
578                                 main_cmds.names[i]->len = 0;
579                                 continue;
580                         }
581                 }
582
583                 main_cmds.names[i]->len =
584                         levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
585         }
586         FREE_AND_NULL(common_cmds);
587
588         QSORT(main_cmds.names, main_cmds.cnt, levenshtein_compare);
589
590         if (!main_cmds.cnt)
591                 die(_("Uh oh. Your system reports no Git commands at all."));
592
593         /* skip and count prefix matches */
594         for (n = 0; n < main_cmds.cnt && !main_cmds.names[n]->len; n++)
595                 ; /* still counting */
596
597         if (main_cmds.cnt <= n) {
598                 /* prefix matches with everything? that is too ambiguous */
599                 best_similarity = SIMILARITY_FLOOR + 1;
600         } else {
601                 /* count all the most similar ones */
602                 for (best_similarity = main_cmds.names[n++]->len;
603                      (n < main_cmds.cnt &&
604                       best_similarity == main_cmds.names[n]->len);
605                      n++)
606                         ; /* still counting */
607         }
608         if (autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {
609                 const char *assumed = main_cmds.names[0]->name;
610                 main_cmds.names[0] = NULL;
611                 clean_cmdnames(&main_cmds);
612                 fprintf_ln(stderr,
613                            _("WARNING: You called a Git command named '%s', "
614                              "which does not exist."),
615                            cmd);
616                 if (autocorrect == AUTOCORRECT_IMMEDIATELY)
617                         fprintf_ln(stderr,
618                                    _("Continuing under the assumption that "
619                                      "you meant '%s'."),
620                                    assumed);
621                 else {
622                         fprintf_ln(stderr,
623                                    _("Continuing in %0.1f seconds, "
624                                      "assuming that you meant '%s'."),
625                                    (float)autocorrect/10.0, assumed);
626                         sleep_millisec(autocorrect * 100);
627                 }
628                 return assumed;
629         }
630
631         fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
632
633         if (SIMILAR_ENOUGH(best_similarity)) {
634                 fprintf_ln(stderr,
635                            Q_("\nThe most similar command is",
636                               "\nThe most similar commands are",
637                            n));
638
639                 for (i = 0; i < n; i++)
640                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
641         }
642
643         exit(1);
644 }
645
646 void get_version_info(struct strbuf *buf, int show_build_options)
647 {
648         /*
649          * The format of this string should be kept stable for compatibility
650          * with external projects that rely on the output of "git version".
651          *
652          * Always show the version, even if other options are given.
653          */
654         strbuf_addf(buf, "git version %s\n", git_version_string);
655
656         if (show_build_options) {
657                 strbuf_addf(buf, "cpu: %s\n", GIT_HOST_CPU);
658                 if (git_built_from_commit_string[0])
659                         strbuf_addf(buf, "built from commit: %s\n",
660                                git_built_from_commit_string);
661                 else
662                         strbuf_addstr(buf, "no commit associated with this build\n");
663                 strbuf_addf(buf, "sizeof-long: %d\n", (int)sizeof(long));
664                 strbuf_addf(buf, "sizeof-size_t: %d\n", (int)sizeof(size_t));
665                 strbuf_addf(buf, "shell-path: %s\n", SHELL_PATH);
666                 /* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
667         }
668 }
669
670 int cmd_version(int argc, const char **argv, const char *prefix)
671 {
672         struct strbuf buf = STRBUF_INIT;
673         int build_options = 0;
674         const char * const usage[] = {
675                 N_("git version [<options>]"),
676                 NULL
677         };
678         struct option options[] = {
679                 OPT_BOOL(0, "build-options", &build_options,
680                          "also print build options"),
681                 OPT_END()
682         };
683
684         argc = parse_options(argc, argv, prefix, options, usage, 0);
685
686         get_version_info(&buf, build_options);
687         printf("%s", buf.buf);
688
689         strbuf_release(&buf);
690
691         return 0;
692 }
693
694 struct similar_ref_cb {
695         const char *base_ref;
696         struct string_list *similar_refs;
697 };
698
699 static int append_similar_ref(const char *refname, const struct object_id *oid,
700                               int flags, void *cb_data)
701 {
702         struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
703         char *branch = strrchr(refname, '/') + 1;
704
705         /* A remote branch of the same name is deemed similar */
706         if (starts_with(refname, "refs/remotes/") &&
707             !strcmp(branch, cb->base_ref))
708                 string_list_append_nodup(cb->similar_refs,
709                                          shorten_unambiguous_ref(refname, 1));
710         return 0;
711 }
712
713 static struct string_list guess_refs(const char *ref)
714 {
715         struct similar_ref_cb ref_cb;
716         struct string_list similar_refs = STRING_LIST_INIT_DUP;
717
718         ref_cb.base_ref = ref;
719         ref_cb.similar_refs = &similar_refs;
720         for_each_ref(append_similar_ref, &ref_cb);
721         return similar_refs;
722 }
723
724 NORETURN void help_unknown_ref(const char *ref, const char *cmd,
725                                const char *error)
726 {
727         int i;
728         struct string_list suggested_refs = guess_refs(ref);
729
730         fprintf_ln(stderr, _("%s: %s - %s"), cmd, ref, error);
731
732         if (suggested_refs.nr > 0) {
733                 fprintf_ln(stderr,
734                            Q_("\nDid you mean this?",
735                               "\nDid you mean one of these?",
736                               suggested_refs.nr));
737                 for (i = 0; i < suggested_refs.nr; i++)
738                         fprintf(stderr, "\t%s\n", suggested_refs.items[i].string);
739         }
740
741         string_list_clear(&suggested_refs, 0);
742         exit(1);
743 }