Merge branch 'nd/maint-clone-gitdir' into maint
[git/git.git] / submodule.c
1 #include "cache.h"
2 #include "submodule.h"
3 #include "dir.h"
4 #include "diff.h"
5 #include "commit.h"
6 #include "revision.h"
7 #include "run-command.h"
8 #include "diffcore.h"
9 #include "refs.h"
10 #include "string-list.h"
11
12 static struct string_list config_name_for_path;
13 static struct string_list config_fetch_recurse_submodules_for_name;
14 static struct string_list config_ignore_for_name;
15 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
16 static struct string_list changed_submodule_paths;
17 /*
18 * The following flag is set if the .gitmodules file is unmerged. We then
19 * disable recursion for all submodules where .git/config doesn't have a
20 * matching config entry because we can't guess what might be configured in
21 * .gitmodules unless the user resolves the conflict. When a command line
22 * option is given (which always overrides configuration) this flag will be
23 * ignored.
24 */
25 static int gitmodules_is_unmerged;
26
27 static int add_submodule_odb(const char *path)
28 {
29 struct strbuf objects_directory = STRBUF_INIT;
30 struct alternate_object_database *alt_odb;
31 int ret = 0;
32 const char *git_dir;
33
34 strbuf_addf(&objects_directory, "%s/.git", path);
35 git_dir = read_gitfile(objects_directory.buf);
36 if (git_dir) {
37 strbuf_reset(&objects_directory);
38 strbuf_addstr(&objects_directory, git_dir);
39 }
40 strbuf_addstr(&objects_directory, "/objects/");
41 if (!is_directory(objects_directory.buf)) {
42 ret = -1;
43 goto done;
44 }
45 /* avoid adding it twice */
46 for (alt_odb = alt_odb_list; alt_odb; alt_odb = alt_odb->next)
47 if (alt_odb->name - alt_odb->base == objects_directory.len &&
48 !strncmp(alt_odb->base, objects_directory.buf,
49 objects_directory.len))
50 goto done;
51
52 alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
53 alt_odb->next = alt_odb_list;
54 strcpy(alt_odb->base, objects_directory.buf);
55 alt_odb->name = alt_odb->base + objects_directory.len;
56 alt_odb->name[2] = '/';
57 alt_odb->name[40] = '\0';
58 alt_odb->name[41] = '\0';
59 alt_odb_list = alt_odb;
60 prepare_alt_odb();
61 done:
62 strbuf_release(&objects_directory);
63 return ret;
64 }
65
66 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
67 const char *path)
68 {
69 struct string_list_item *path_option, *ignore_option;
70 path_option = unsorted_string_list_lookup(&config_name_for_path, path);
71 if (path_option) {
72 ignore_option = unsorted_string_list_lookup(&config_ignore_for_name, path_option->util);
73 if (ignore_option)
74 handle_ignore_submodules_arg(diffopt, ignore_option->util);
75 else if (gitmodules_is_unmerged)
76 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
77 }
78 }
79
80 int submodule_config(const char *var, const char *value, void *cb)
81 {
82 if (!prefixcmp(var, "submodule."))
83 return parse_submodule_config_option(var, value);
84 else if (!strcmp(var, "fetch.recursesubmodules")) {
85 config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
86 return 0;
87 }
88 return 0;
89 }
90
91 void gitmodules_config(void)
92 {
93 const char *work_tree = get_git_work_tree();
94 if (work_tree) {
95 struct strbuf gitmodules_path = STRBUF_INIT;
96 int pos;
97 strbuf_addstr(&gitmodules_path, work_tree);
98 strbuf_addstr(&gitmodules_path, "/.gitmodules");
99 if (read_cache() < 0)
100 die("index file corrupt");
101 pos = cache_name_pos(".gitmodules", 11);
102 if (pos < 0) { /* .gitmodules not found or isn't merged */
103 pos = -1 - pos;
104 if (active_nr > pos) { /* there is a .gitmodules */
105 const struct cache_entry *ce = active_cache[pos];
106 if (ce_namelen(ce) == 11 &&
107 !memcmp(ce->name, ".gitmodules", 11))
108 gitmodules_is_unmerged = 1;
109 }
110 }
111
112 if (!gitmodules_is_unmerged)
113 git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
114 strbuf_release(&gitmodules_path);
115 }
116 }
117
118 int parse_submodule_config_option(const char *var, const char *value)
119 {
120 int len;
121 struct string_list_item *config;
122 struct strbuf submodname = STRBUF_INIT;
123
124 var += 10; /* Skip "submodule." */
125
126 len = strlen(var);
127 if ((len > 5) && !strcmp(var + len - 5, ".path")) {
128 strbuf_add(&submodname, var, len - 5);
129 config = unsorted_string_list_lookup(&config_name_for_path, value);
130 if (config)
131 free(config->util);
132 else
133 config = string_list_append(&config_name_for_path, xstrdup(value));
134 config->util = strbuf_detach(&submodname, NULL);
135 strbuf_release(&submodname);
136 } else if ((len > 23) && !strcmp(var + len - 23, ".fetchrecursesubmodules")) {
137 strbuf_add(&submodname, var, len - 23);
138 config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, submodname.buf);
139 if (!config)
140 config = string_list_append(&config_fetch_recurse_submodules_for_name,
141 strbuf_detach(&submodname, NULL));
142 config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
143 strbuf_release(&submodname);
144 } else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
145 if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
146 strcmp(value, "all") && strcmp(value, "none")) {
147 warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
148 return 0;
149 }
150
151 strbuf_add(&submodname, var, len - 7);
152 config = unsorted_string_list_lookup(&config_ignore_for_name, submodname.buf);
153 if (config)
154 free(config->util);
155 else
156 config = string_list_append(&config_ignore_for_name,
157 strbuf_detach(&submodname, NULL));
158 strbuf_release(&submodname);
159 config->util = xstrdup(value);
160 return 0;
161 }
162 return 0;
163 }
164
165 void handle_ignore_submodules_arg(struct diff_options *diffopt,
166 const char *arg)
167 {
168 DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
169 DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
170 DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
171
172 if (!strcmp(arg, "all"))
173 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
174 else if (!strcmp(arg, "untracked"))
175 DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
176 else if (!strcmp(arg, "dirty"))
177 DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
178 else if (strcmp(arg, "none"))
179 die("bad --ignore-submodules argument: %s", arg);
180 }
181
182 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
183 struct commit *left, struct commit *right,
184 int *fast_forward, int *fast_backward)
185 {
186 struct commit_list *merge_bases, *list;
187
188 init_revisions(rev, NULL);
189 setup_revisions(0, NULL, rev, NULL);
190 rev->left_right = 1;
191 rev->first_parent_only = 1;
192 left->object.flags |= SYMMETRIC_LEFT;
193 add_pending_object(rev, &left->object, path);
194 add_pending_object(rev, &right->object, path);
195 merge_bases = get_merge_bases(left, right, 1);
196 if (merge_bases) {
197 if (merge_bases->item == left)
198 *fast_forward = 1;
199 else if (merge_bases->item == right)
200 *fast_backward = 1;
201 }
202 for (list = merge_bases; list; list = list->next) {
203 list->item->object.flags |= UNINTERESTING;
204 add_pending_object(rev, &list->item->object,
205 sha1_to_hex(list->item->object.sha1));
206 }
207 return prepare_revision_walk(rev);
208 }
209
210 static void print_submodule_summary(struct rev_info *rev, FILE *f,
211 const char *del, const char *add, const char *reset)
212 {
213 static const char format[] = " %m %s";
214 struct strbuf sb = STRBUF_INIT;
215 struct commit *commit;
216
217 while ((commit = get_revision(rev))) {
218 struct pretty_print_context ctx = {0};
219 ctx.date_mode = rev->date_mode;
220 strbuf_setlen(&sb, 0);
221 if (commit->object.flags & SYMMETRIC_LEFT) {
222 if (del)
223 strbuf_addstr(&sb, del);
224 }
225 else if (add)
226 strbuf_addstr(&sb, add);
227 format_commit_message(commit, format, &sb, &ctx);
228 if (reset)
229 strbuf_addstr(&sb, reset);
230 strbuf_addch(&sb, '\n');
231 fprintf(f, "%s", sb.buf);
232 }
233 strbuf_release(&sb);
234 }
235
236 int parse_fetch_recurse_submodules_arg(const char *opt, const char *arg)
237 {
238 switch (git_config_maybe_bool(opt, arg)) {
239 case 1:
240 return RECURSE_SUBMODULES_ON;
241 case 0:
242 return RECURSE_SUBMODULES_OFF;
243 default:
244 if (!strcmp(arg, "on-demand"))
245 return RECURSE_SUBMODULES_ON_DEMAND;
246 die("bad %s argument: %s", opt, arg);
247 }
248 }
249
250 void show_submodule_summary(FILE *f, const char *path,
251 unsigned char one[20], unsigned char two[20],
252 unsigned dirty_submodule,
253 const char *del, const char *add, const char *reset)
254 {
255 struct rev_info rev;
256 struct commit *left = left, *right = right;
257 const char *message = NULL;
258 struct strbuf sb = STRBUF_INIT;
259 int fast_forward = 0, fast_backward = 0;
260
261 if (is_null_sha1(two))
262 message = "(submodule deleted)";
263 else if (add_submodule_odb(path))
264 message = "(not checked out)";
265 else if (is_null_sha1(one))
266 message = "(new submodule)";
267 else if (!(left = lookup_commit_reference(one)) ||
268 !(right = lookup_commit_reference(two)))
269 message = "(commits not present)";
270
271 if (!message &&
272 prepare_submodule_summary(&rev, path, left, right,
273 &fast_forward, &fast_backward))
274 message = "(revision walker failed)";
275
276 if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
277 fprintf(f, "Submodule %s contains untracked content\n", path);
278 if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
279 fprintf(f, "Submodule %s contains modified content\n", path);
280
281 if (!hashcmp(one, two)) {
282 strbuf_release(&sb);
283 return;
284 }
285
286 strbuf_addf(&sb, "Submodule %s %s..", path,
287 find_unique_abbrev(one, DEFAULT_ABBREV));
288 if (!fast_backward && !fast_forward)
289 strbuf_addch(&sb, '.');
290 strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
291 if (message)
292 strbuf_addf(&sb, " %s\n", message);
293 else
294 strbuf_addf(&sb, "%s:\n", fast_backward ? " (rewind)" : "");
295 fwrite(sb.buf, sb.len, 1, f);
296
297 if (!message) {
298 print_submodule_summary(&rev, f, del, add, reset);
299 clear_commit_marks(left, ~0);
300 clear_commit_marks(right, ~0);
301 }
302
303 strbuf_release(&sb);
304 }
305
306 void set_config_fetch_recurse_submodules(int value)
307 {
308 config_fetch_recurse_submodules = value;
309 }
310
311 static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
312 {
313 int is_present = 0;
314 if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
315 /* Even if the submodule is checked out and the commit is
316 * present, make sure it is reachable from a ref. */
317 struct child_process cp;
318 const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
319 struct strbuf buf = STRBUF_INIT;
320
321 argv[3] = sha1_to_hex(sha1);
322 memset(&cp, 0, sizeof(cp));
323 cp.argv = argv;
324 cp.env = local_repo_env;
325 cp.git_cmd = 1;
326 cp.no_stdin = 1;
327 cp.out = -1;
328 cp.dir = path;
329 if (!run_command(&cp) && !strbuf_read(&buf, cp.out, 1024))
330 is_present = 1;
331
332 close(cp.out);
333 strbuf_release(&buf);
334 }
335 return is_present;
336 }
337
338 static void submodule_collect_changed_cb(struct diff_queue_struct *q,
339 struct diff_options *options,
340 void *data)
341 {
342 int i;
343 for (i = 0; i < q->nr; i++) {
344 struct diff_filepair *p = q->queue[i];
345 if (!S_ISGITLINK(p->two->mode))
346 continue;
347
348 if (S_ISGITLINK(p->one->mode)) {
349 /* NEEDSWORK: We should honor the name configured in
350 * the .gitmodules file of the commit we are examining
351 * here to be able to correctly follow submodules
352 * being moved around. */
353 struct string_list_item *path;
354 path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
355 if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
356 string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
357 } else {
358 /* Submodule is new or was moved here */
359 /* NEEDSWORK: When the .git directories of submodules
360 * live inside the superprojects .git directory some
361 * day we should fetch new submodules directly into
362 * that location too when config or options request
363 * that so they can be checked out from there. */
364 continue;
365 }
366 }
367 }
368
369 void check_for_new_submodule_commits(unsigned char new_sha1[20])
370 {
371 struct rev_info rev;
372 struct commit *commit;
373 const char *argv[] = {NULL, NULL, "--not", "--all", NULL};
374 int argc = ARRAY_SIZE(argv) - 1;
375
376 /* No need to check if there are no submodules configured */
377 if (!config_name_for_path.nr)
378 return;
379
380 init_revisions(&rev, NULL);
381 argv[1] = xstrdup(sha1_to_hex(new_sha1));
382 setup_revisions(argc, argv, &rev, NULL);
383 if (prepare_revision_walk(&rev))
384 die("revision walk setup failed");
385
386 /*
387 * Collect all submodules (whether checked out or not) for which new
388 * commits have been recorded upstream in "changed_submodule_paths".
389 */
390 while ((commit = get_revision(&rev))) {
391 struct commit_list *parent = commit->parents;
392 while (parent) {
393 struct diff_options diff_opts;
394 diff_setup(&diff_opts);
395 DIFF_OPT_SET(&diff_opts, RECURSIVE);
396 diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
397 diff_opts.format_callback = submodule_collect_changed_cb;
398 if (diff_setup_done(&diff_opts) < 0)
399 die("diff_setup_done failed");
400 diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
401 diffcore_std(&diff_opts);
402 diff_flush(&diff_opts);
403 parent = parent->next;
404 }
405 }
406 free((char *)argv[1]);
407 }
408
409 int fetch_populated_submodules(int num_options, const char **options,
410 const char *prefix, int command_line_option,
411 int quiet)
412 {
413 int i, result = 0, argc = 0, default_argc;
414 struct child_process cp;
415 const char **argv;
416 struct string_list_item *name_for_path;
417 const char *work_tree = get_git_work_tree();
418 if (!work_tree)
419 goto out;
420
421 if (!the_index.initialized)
422 if (read_cache() < 0)
423 die("index file corrupt");
424
425 /* 6: "fetch" (options) --recurse-submodules-default default "--submodule-prefix" prefix NULL */
426 argv = xcalloc(num_options + 6, sizeof(const char *));
427 argv[argc++] = "fetch";
428 for (i = 0; i < num_options; i++)
429 argv[argc++] = options[i];
430 argv[argc++] = "--recurse-submodules-default";
431 default_argc = argc++;
432 argv[argc++] = "--submodule-prefix";
433
434 memset(&cp, 0, sizeof(cp));
435 cp.argv = argv;
436 cp.env = local_repo_env;
437 cp.git_cmd = 1;
438 cp.no_stdin = 1;
439
440 for (i = 0; i < active_nr; i++) {
441 struct strbuf submodule_path = STRBUF_INIT;
442 struct strbuf submodule_git_dir = STRBUF_INIT;
443 struct strbuf submodule_prefix = STRBUF_INIT;
444 struct cache_entry *ce = active_cache[i];
445 const char *git_dir, *name, *default_argv;
446
447 if (!S_ISGITLINK(ce->ce_mode))
448 continue;
449
450 name = ce->name;
451 name_for_path = unsorted_string_list_lookup(&config_name_for_path, ce->name);
452 if (name_for_path)
453 name = name_for_path->util;
454
455 default_argv = "yes";
456 if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
457 struct string_list_item *fetch_recurse_submodules_option;
458 fetch_recurse_submodules_option = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name);
459 if (fetch_recurse_submodules_option) {
460 if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_OFF)
461 continue;
462 if ((intptr_t)fetch_recurse_submodules_option->util == RECURSE_SUBMODULES_ON_DEMAND) {
463 if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
464 continue;
465 default_argv = "on-demand";
466 }
467 } else {
468 if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
469 gitmodules_is_unmerged)
470 continue;
471 if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
472 if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
473 continue;
474 default_argv = "on-demand";
475 }
476 }
477 } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
478 if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
479 continue;
480 default_argv = "on-demand";
481 }
482
483 strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
484 strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
485 strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
486 git_dir = read_gitfile(submodule_git_dir.buf);
487 if (!git_dir)
488 git_dir = submodule_git_dir.buf;
489 if (is_directory(git_dir)) {
490 if (!quiet)
491 printf("Fetching submodule %s%s\n", prefix, ce->name);
492 cp.dir = submodule_path.buf;
493 argv[default_argc] = default_argv;
494 argv[argc] = submodule_prefix.buf;
495 if (run_command(&cp))
496 result = 1;
497 }
498 strbuf_release(&submodule_path);
499 strbuf_release(&submodule_git_dir);
500 strbuf_release(&submodule_prefix);
501 }
502 free(argv);
503 out:
504 string_list_clear(&changed_submodule_paths, 1);
505 return result;
506 }
507
508 unsigned is_submodule_modified(const char *path, int ignore_untracked)
509 {
510 ssize_t len;
511 struct child_process cp;
512 const char *argv[] = {
513 "status",
514 "--porcelain",
515 NULL,
516 NULL,
517 };
518 struct strbuf buf = STRBUF_INIT;
519 unsigned dirty_submodule = 0;
520 const char *line, *next_line;
521 const char *git_dir;
522
523 strbuf_addf(&buf, "%s/.git", path);
524 git_dir = read_gitfile(buf.buf);
525 if (!git_dir)
526 git_dir = buf.buf;
527 if (!is_directory(git_dir)) {
528 strbuf_release(&buf);
529 /* The submodule is not checked out, so it is not modified */
530 return 0;
531
532 }
533 strbuf_reset(&buf);
534
535 if (ignore_untracked)
536 argv[2] = "-uno";
537
538 memset(&cp, 0, sizeof(cp));
539 cp.argv = argv;
540 cp.env = local_repo_env;
541 cp.git_cmd = 1;
542 cp.no_stdin = 1;
543 cp.out = -1;
544 cp.dir = path;
545 if (start_command(&cp))
546 die("Could not run git status --porcelain");
547
548 len = strbuf_read(&buf, cp.out, 1024);
549 line = buf.buf;
550 while (len > 2) {
551 if ((line[0] == '?') && (line[1] == '?')) {
552 dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
553 if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
554 break;
555 } else {
556 dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
557 if (ignore_untracked ||
558 (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
559 break;
560 }
561 next_line = strchr(line, '\n');
562 if (!next_line)
563 break;
564 next_line++;
565 len -= (next_line - line);
566 line = next_line;
567 }
568 close(cp.out);
569
570 if (finish_command(&cp))
571 die("git status --porcelain failed");
572
573 strbuf_release(&buf);
574 return dirty_submodule;
575 }
576
577 static int find_first_merges(struct object_array *result, const char *path,
578 struct commit *a, struct commit *b)
579 {
580 int i, j;
581 struct object_array merges;
582 struct commit *commit;
583 int contains_another;
584
585 char merged_revision[42];
586 const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
587 "--all", merged_revision, NULL };
588 struct rev_info revs;
589 struct setup_revision_opt rev_opts;
590
591 memset(&merges, 0, sizeof(merges));
592 memset(result, 0, sizeof(struct object_array));
593 memset(&rev_opts, 0, sizeof(rev_opts));
594
595 /* get all revisions that merge commit a */
596 snprintf(merged_revision, sizeof(merged_revision), "^%s",
597 sha1_to_hex(a->object.sha1));
598 init_revisions(&revs, NULL);
599 rev_opts.submodule = path;
600 setup_revisions(sizeof(rev_args)/sizeof(char *)-1, rev_args, &revs, &rev_opts);
601
602 /* save all revisions from the above list that contain b */
603 if (prepare_revision_walk(&revs))
604 die("revision walk setup failed");
605 while ((commit = get_revision(&revs)) != NULL) {
606 struct object *o = &(commit->object);
607 if (in_merge_bases(b, &commit, 1))
608 add_object_array(o, NULL, &merges);
609 }
610
611 /* Now we've got all merges that contain a and b. Prune all
612 * merges that contain another found merge and save them in
613 * result.
614 */
615 for (i = 0; i < merges.nr; i++) {
616 struct commit *m1 = (struct commit *) merges.objects[i].item;
617
618 contains_another = 0;
619 for (j = 0; j < merges.nr; j++) {
620 struct commit *m2 = (struct commit *) merges.objects[j].item;
621 if (i != j && in_merge_bases(m2, &m1, 1)) {
622 contains_another = 1;
623 break;
624 }
625 }
626
627 if (!contains_another)
628 add_object_array(merges.objects[i].item,
629 merges.objects[i].name, result);
630 }
631
632 free(merges.objects);
633 return result->nr;
634 }
635
636 static void print_commit(struct commit *commit)
637 {
638 struct strbuf sb = STRBUF_INIT;
639 struct pretty_print_context ctx = {0};
640 ctx.date_mode = DATE_NORMAL;
641 format_commit_message(commit, " %h: %m %s", &sb, &ctx);
642 fprintf(stderr, "%s\n", sb.buf);
643 strbuf_release(&sb);
644 }
645
646 #define MERGE_WARNING(path, msg) \
647 warning("Failed to merge submodule %s (%s)", path, msg);
648
649 int merge_submodule(unsigned char result[20], const char *path,
650 const unsigned char base[20], const unsigned char a[20],
651 const unsigned char b[20])
652 {
653 struct commit *commit_base, *commit_a, *commit_b;
654 int parent_count;
655 struct object_array merges;
656
657 int i;
658
659 /* store a in result in case we fail */
660 hashcpy(result, a);
661
662 /* we can not handle deletion conflicts */
663 if (is_null_sha1(base))
664 return 0;
665 if (is_null_sha1(a))
666 return 0;
667 if (is_null_sha1(b))
668 return 0;
669
670 if (add_submodule_odb(path)) {
671 MERGE_WARNING(path, "not checked out");
672 return 0;
673 }
674
675 if (!(commit_base = lookup_commit_reference(base)) ||
676 !(commit_a = lookup_commit_reference(a)) ||
677 !(commit_b = lookup_commit_reference(b))) {
678 MERGE_WARNING(path, "commits not present");
679 return 0;
680 }
681
682 /* check whether both changes are forward */
683 if (!in_merge_bases(commit_base, &commit_a, 1) ||
684 !in_merge_bases(commit_base, &commit_b, 1)) {
685 MERGE_WARNING(path, "commits don't follow merge-base");
686 return 0;
687 }
688
689 /* Case #1: a is contained in b or vice versa */
690 if (in_merge_bases(commit_a, &commit_b, 1)) {
691 hashcpy(result, b);
692 return 1;
693 }
694 if (in_merge_bases(commit_b, &commit_a, 1)) {
695 hashcpy(result, a);
696 return 1;
697 }
698
699 /*
700 * Case #2: There are one or more merges that contain a and b in
701 * the submodule. If there is only one, then present it as a
702 * suggestion to the user, but leave it marked unmerged so the
703 * user needs to confirm the resolution.
704 */
705
706 /* find commit which merges them */
707 parent_count = find_first_merges(&merges, path, commit_a, commit_b);
708 switch (parent_count) {
709 case 0:
710 MERGE_WARNING(path, "merge following commits not found");
711 break;
712
713 case 1:
714 MERGE_WARNING(path, "not fast-forward");
715 fprintf(stderr, "Found a possible merge resolution "
716 "for the submodule:\n");
717 print_commit((struct commit *) merges.objects[0].item);
718 fprintf(stderr,
719 "If this is correct simply add it to the index "
720 "for example\n"
721 "by using:\n\n"
722 " git update-index --cacheinfo 160000 %s \"%s\"\n\n"
723 "which will accept this suggestion.\n",
724 sha1_to_hex(merges.objects[0].item->sha1), path);
725 break;
726
727 default:
728 MERGE_WARNING(path, "multiple merges found");
729 for (i = 0; i < merges.nr; i++)
730 print_commit((struct commit *) merges.objects[i].item);
731 }
732
733 free(merges.objects);
734 return 0;
735 }