Merge branch 'bl/userdiff-octave'
[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 / Synching 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_const("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_common_guides_help(void)
401 {
402         struct category_description catdesc[] = {
403                 { CAT_guide, N_("The common Git guides are:") },
404                 { 0, NULL }
405         };
406         print_cmd_by_category(catdesc, NULL);
407         putchar('\n');
408 }
409
410 struct slot_expansion {
411         const char *prefix;
412         const char *placeholder;
413         void (*fn)(struct string_list *list, const char *prefix);
414         int found;
415 };
416
417 void list_config_help(int for_human)
418 {
419         struct slot_expansion slot_expansions[] = {
420                 { "advice", "*", list_config_advices },
421                 { "color.branch", "<slot>", list_config_color_branch_slots },
422                 { "color.decorate", "<slot>", list_config_color_decorate_slots },
423                 { "color.diff", "<slot>", list_config_color_diff_slots },
424                 { "color.grep", "<slot>", list_config_color_grep_slots },
425                 { "color.interactive", "<slot>", list_config_color_interactive_slots },
426                 { "color.remote", "<slot>", list_config_color_sideband_slots },
427                 { "color.status", "<slot>", list_config_color_status_slots },
428                 { "fsck", "<msg-id>", list_config_fsck_msg_ids },
429                 { "receive.fsck", "<msg-id>", list_config_fsck_msg_ids },
430                 { NULL, NULL, NULL }
431         };
432         const char **p;
433         struct slot_expansion *e;
434         struct string_list keys = STRING_LIST_INIT_DUP;
435         int i;
436
437         for (p = config_name_list; *p; p++) {
438                 const char *var = *p;
439                 struct strbuf sb = STRBUF_INIT;
440
441                 for (e = slot_expansions; e->prefix; e++) {
442
443                         strbuf_reset(&sb);
444                         strbuf_addf(&sb, "%s.%s", e->prefix, e->placeholder);
445                         if (!strcasecmp(var, sb.buf)) {
446                                 e->fn(&keys, e->prefix);
447                                 e->found++;
448                                 break;
449                         }
450                 }
451                 strbuf_release(&sb);
452                 if (!e->prefix)
453                         string_list_append(&keys, var);
454         }
455
456         for (e = slot_expansions; e->prefix; e++)
457                 if (!e->found)
458                         BUG("slot_expansion %s.%s is not used",
459                             e->prefix, e->placeholder);
460
461         string_list_sort(&keys);
462         for (i = 0; i < keys.nr; i++) {
463                 const char *var = keys.items[i].string;
464                 const char *wildcard, *tag, *cut;
465
466                 if (for_human) {
467                         puts(var);
468                         continue;
469                 }
470
471                 wildcard = strchr(var, '*');
472                 tag = strchr(var, '<');
473
474                 if (!wildcard && !tag) {
475                         puts(var);
476                         continue;
477                 }
478
479                 if (wildcard && !tag)
480                         cut = wildcard;
481                 else if (!wildcard && tag)
482                         cut = tag;
483                 else
484                         cut = wildcard < tag ? wildcard : tag;
485
486                 /*
487                  * We may produce duplicates, but that's up to
488                  * git-completion.bash to handle
489                  */
490                 printf("%.*s\n", (int)(cut - var), var);
491         }
492         string_list_clear(&keys, 0);
493 }
494
495 static int get_alias(const char *var, const char *value, void *data)
496 {
497         struct string_list *list = data;
498
499         if (skip_prefix(var, "alias.", &var))
500                 string_list_append(list, var)->util = xstrdup(value);
501
502         return 0;
503 }
504
505 void list_all_cmds_help(void)
506 {
507         struct string_list others = STRING_LIST_INIT_DUP;
508         struct string_list alias_list = STRING_LIST_INIT_DUP;
509         struct cmdname_help *aliases;
510         int i, longest;
511
512         printf_ln(_("See 'git help <command>' to read about a specific subcommand"));
513         print_cmd_by_category(main_categories, &longest);
514
515         list_all_other_cmds(&others);
516         if (others.nr)
517                 printf("\n%s\n", _("External commands"));
518         for (i = 0; i < others.nr; i++)
519                 printf("   %s\n", others.items[i].string);
520         string_list_clear(&others, 0);
521
522         git_config(get_alias, &alias_list);
523         string_list_sort(&alias_list);
524
525         for (i = 0; i < alias_list.nr; i++) {
526                 size_t len = strlen(alias_list.items[i].string);
527                 if (longest < len)
528                         longest = len;
529         }
530
531         if (alias_list.nr) {
532                 printf("\n%s\n", _("Command aliases"));
533                 ALLOC_ARRAY(aliases, alias_list.nr + 1);
534                 for (i = 0; i < alias_list.nr; i++) {
535                         aliases[i].name = alias_list.items[i].string;
536                         aliases[i].help = alias_list.items[i].util;
537                         aliases[i].category = 1;
538                 }
539                 aliases[alias_list.nr].name = NULL;
540                 print_command_list(aliases, 1, longest);
541                 free(aliases);
542         }
543         string_list_clear(&alias_list, 1);
544 }
545
546 int is_in_cmdlist(struct cmdnames *c, const char *s)
547 {
548         int i;
549         for (i = 0; i < c->cnt; i++)
550                 if (!strcmp(s, c->names[i]->name))
551                         return 1;
552         return 0;
553 }
554
555 static int autocorrect;
556 static struct cmdnames aliases;
557
558 static int git_unknown_cmd_config(const char *var, const char *value, void *cb)
559 {
560         const char *p;
561
562         if (!strcmp(var, "help.autocorrect"))
563                 autocorrect = git_config_int(var,value);
564         /* Also use aliases for command lookup */
565         if (skip_prefix(var, "alias.", &p))
566                 add_cmdname(&aliases, p, strlen(p));
567
568         return git_default_config(var, value, cb);
569 }
570
571 static int levenshtein_compare(const void *p1, const void *p2)
572 {
573         const struct cmdname *const *c1 = p1, *const *c2 = p2;
574         const char *s1 = (*c1)->name, *s2 = (*c2)->name;
575         int l1 = (*c1)->len;
576         int l2 = (*c2)->len;
577         return l1 != l2 ? l1 - l2 : strcmp(s1, s2);
578 }
579
580 static void add_cmd_list(struct cmdnames *cmds, struct cmdnames *old)
581 {
582         int i;
583         ALLOC_GROW(cmds->names, cmds->cnt + old->cnt, cmds->alloc);
584
585         for (i = 0; i < old->cnt; i++)
586                 cmds->names[cmds->cnt++] = old->names[i];
587         FREE_AND_NULL(old->names);
588         old->cnt = 0;
589 }
590
591 /* An empirically derived magic number */
592 #define SIMILARITY_FLOOR 7
593 #define SIMILAR_ENOUGH(x) ((x) < SIMILARITY_FLOOR)
594
595 static const char bad_interpreter_advice[] =
596         N_("'%s' appears to be a git command, but we were not\n"
597         "able to execute it. Maybe git-%s is broken?");
598
599 const char *help_unknown_cmd(const char *cmd)
600 {
601         int i, n, best_similarity = 0;
602         struct cmdnames main_cmds, other_cmds;
603         struct cmdname_help *common_cmds;
604
605         memset(&main_cmds, 0, sizeof(main_cmds));
606         memset(&other_cmds, 0, sizeof(other_cmds));
607         memset(&aliases, 0, sizeof(aliases));
608
609         read_early_config(git_unknown_cmd_config, NULL);
610
611         load_command_list("git-", &main_cmds, &other_cmds);
612
613         add_cmd_list(&main_cmds, &aliases);
614         add_cmd_list(&main_cmds, &other_cmds);
615         QSORT(main_cmds.names, main_cmds.cnt, cmdname_compare);
616         uniq(&main_cmds);
617
618         extract_cmds(&common_cmds, common_mask);
619
620         /* This abuses cmdname->len for levenshtein distance */
621         for (i = 0, n = 0; i < main_cmds.cnt; i++) {
622                 int cmp = 0; /* avoid compiler stupidity */
623                 const char *candidate = main_cmds.names[i]->name;
624
625                 /*
626                  * An exact match means we have the command, but
627                  * for some reason exec'ing it gave us ENOENT; probably
628                  * it's a bad interpreter in the #! line.
629                  */
630                 if (!strcmp(candidate, cmd))
631                         die(_(bad_interpreter_advice), cmd, cmd);
632
633                 /* Does the candidate appear in common_cmds list? */
634                 while (common_cmds[n].name &&
635                        (cmp = strcmp(common_cmds[n].name, candidate)) < 0)
636                         n++;
637                 if (common_cmds[n].name && !cmp) {
638                         /* Yes, this is one of the common commands */
639                         n++; /* use the entry from common_cmds[] */
640                         if (starts_with(candidate, cmd)) {
641                                 /* Give prefix match a very good score */
642                                 main_cmds.names[i]->len = 0;
643                                 continue;
644                         }
645                 }
646
647                 main_cmds.names[i]->len =
648                         levenshtein(cmd, candidate, 0, 2, 1, 3) + 1;
649         }
650         FREE_AND_NULL(common_cmds);
651
652         QSORT(main_cmds.names, main_cmds.cnt, levenshtein_compare);
653
654         if (!main_cmds.cnt)
655                 die(_("Uh oh. Your system reports no Git commands at all."));
656
657         /* skip and count prefix matches */
658         for (n = 0; n < main_cmds.cnt && !main_cmds.names[n]->len; n++)
659                 ; /* still counting */
660
661         if (main_cmds.cnt <= n) {
662                 /* prefix matches with everything? that is too ambiguous */
663                 best_similarity = SIMILARITY_FLOOR + 1;
664         } else {
665                 /* count all the most similar ones */
666                 for (best_similarity = main_cmds.names[n++]->len;
667                      (n < main_cmds.cnt &&
668                       best_similarity == main_cmds.names[n]->len);
669                      n++)
670                         ; /* still counting */
671         }
672         if (autocorrect && n == 1 && SIMILAR_ENOUGH(best_similarity)) {
673                 const char *assumed = main_cmds.names[0]->name;
674                 main_cmds.names[0] = NULL;
675                 clean_cmdnames(&main_cmds);
676                 fprintf_ln(stderr,
677                            _("WARNING: You called a Git command named '%s', "
678                              "which does not exist."),
679                            cmd);
680                 if (autocorrect < 0)
681                         fprintf_ln(stderr,
682                                    _("Continuing under the assumption that "
683                                      "you meant '%s'."),
684                                    assumed);
685                 else {
686                         fprintf_ln(stderr,
687                                    _("Continuing in %0.1f seconds, "
688                                      "assuming that you meant '%s'."),
689                                    (float)autocorrect/10.0, assumed);
690                         sleep_millisec(autocorrect * 100);
691                 }
692                 return assumed;
693         }
694
695         fprintf_ln(stderr, _("git: '%s' is not a git command. See 'git --help'."), cmd);
696
697         if (SIMILAR_ENOUGH(best_similarity)) {
698                 fprintf_ln(stderr,
699                            Q_("\nThe most similar command is",
700                               "\nThe most similar commands are",
701                            n));
702
703                 for (i = 0; i < n; i++)
704                         fprintf(stderr, "\t%s\n", main_cmds.names[i]->name);
705         }
706
707         exit(1);
708 }
709
710 int cmd_version(int argc, const char **argv, const char *prefix)
711 {
712         int build_options = 0;
713         const char * const usage[] = {
714                 N_("git version [<options>]"),
715                 NULL
716         };
717         struct option options[] = {
718                 OPT_BOOL(0, "build-options", &build_options,
719                          "also print build options"),
720                 OPT_END()
721         };
722
723         argc = parse_options(argc, argv, prefix, options, usage, 0);
724
725         /*
726          * The format of this string should be kept stable for compatibility
727          * with external projects that rely on the output of "git version".
728          *
729          * Always show the version, even if other options are given.
730          */
731         printf("git version %s\n", git_version_string);
732
733         if (build_options) {
734                 printf("cpu: %s\n", GIT_HOST_CPU);
735                 if (git_built_from_commit_string[0])
736                         printf("built from commit: %s\n",
737                                git_built_from_commit_string);
738                 else
739                         printf("no commit associated with this build\n");
740                 printf("sizeof-long: %d\n", (int)sizeof(long));
741                 printf("sizeof-size_t: %d\n", (int)sizeof(size_t));
742                 /* NEEDSWORK: also save and output GIT-BUILD_OPTIONS? */
743         }
744         return 0;
745 }
746
747 struct similar_ref_cb {
748         const char *base_ref;
749         struct string_list *similar_refs;
750 };
751
752 static int append_similar_ref(const char *refname, const struct object_id *oid,
753                               int flags, void *cb_data)
754 {
755         struct similar_ref_cb *cb = (struct similar_ref_cb *)(cb_data);
756         char *branch = strrchr(refname, '/') + 1;
757
758         /* A remote branch of the same name is deemed similar */
759         if (starts_with(refname, "refs/remotes/") &&
760             !strcmp(branch, cb->base_ref))
761                 string_list_append_nodup(cb->similar_refs,
762                                          shorten_unambiguous_ref(refname, 1));
763         return 0;
764 }
765
766 static struct string_list guess_refs(const char *ref)
767 {
768         struct similar_ref_cb ref_cb;
769         struct string_list similar_refs = STRING_LIST_INIT_DUP;
770
771         ref_cb.base_ref = ref;
772         ref_cb.similar_refs = &similar_refs;
773         for_each_ref(append_similar_ref, &ref_cb);
774         return similar_refs;
775 }
776
777 void help_unknown_ref(const char *ref, const char *cmd, const char *error)
778 {
779         int i;
780         struct string_list suggested_refs = guess_refs(ref);
781
782         fprintf_ln(stderr, _("%s: %s - %s"), cmd, ref, error);
783
784         if (suggested_refs.nr > 0) {
785                 fprintf_ln(stderr,
786                            Q_("\nDid you mean this?",
787                               "\nDid you mean one of these?",
788                               suggested_refs.nr));
789                 for (i = 0; i < suggested_refs.nr; i++)
790                         fprintf(stderr, "\t%s\n", suggested_refs.items[i].string);
791         }
792
793         string_list_clear(&suggested_refs, 0);
794         exit(1);
795 }