submodule: rewrite `module_list` shell function in C
[git] / submodule.c
1 #include "cache.h"
2 #include "submodule-config.h"
3 #include "submodule.h"
4 #include "dir.h"
5 #include "diff.h"
6 #include "commit.h"
7 #include "revision.h"
8 #include "run-command.h"
9 #include "diffcore.h"
10 #include "refs.h"
11 #include "string-list.h"
12 #include "sha1-array.h"
13 #include "argv-array.h"
14 #include "blob.h"
15
16 static int config_fetch_recurse_submodules = RECURSE_SUBMODULES_ON_DEMAND;
17 static struct string_list changed_submodule_paths;
18 static int initialized_fetch_ref_tips;
19 static struct sha1_array ref_tips_before_fetch;
20 static struct sha1_array ref_tips_after_fetch;
21
22 /*
23  * The following flag is set if the .gitmodules file is unmerged. We then
24  * disable recursion for all submodules where .git/config doesn't have a
25  * matching config entry because we can't guess what might be configured in
26  * .gitmodules unless the user resolves the conflict. When a command line
27  * option is given (which always overrides configuration) this flag will be
28  * ignored.
29  */
30 static int gitmodules_is_unmerged;
31
32 /*
33  * This flag is set if the .gitmodules file had unstaged modifications on
34  * startup. This must be checked before allowing modifications to the
35  * .gitmodules file with the intention to stage them later, because when
36  * continuing we would stage the modifications the user didn't stage herself
37  * too. That might change in a future version when we learn to stage the
38  * changes we do ourselves without staging any previous modifications.
39  */
40 static int gitmodules_is_modified;
41
42 int is_staging_gitmodules_ok(void)
43 {
44         return !gitmodules_is_modified;
45 }
46
47 /*
48  * Try to update the "path" entry in the "submodule.<name>" section of the
49  * .gitmodules file. Return 0 only if a .gitmodules file was found, a section
50  * with the correct path=<oldpath> setting was found and we could update it.
51  */
52 int update_path_in_gitmodules(const char *oldpath, const char *newpath)
53 {
54         struct strbuf entry = STRBUF_INIT;
55         const struct submodule *submodule;
56
57         if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
58                 return -1;
59
60         if (gitmodules_is_unmerged)
61                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
62
63         submodule = submodule_from_path(null_sha1, oldpath);
64         if (!submodule || !submodule->name) {
65                 warning(_("Could not find section in .gitmodules where path=%s"), oldpath);
66                 return -1;
67         }
68         strbuf_addstr(&entry, "submodule.");
69         strbuf_addstr(&entry, submodule->name);
70         strbuf_addstr(&entry, ".path");
71         if (git_config_set_in_file(".gitmodules", entry.buf, newpath) < 0) {
72                 /* Maybe the user already did that, don't error out here */
73                 warning(_("Could not update .gitmodules entry %s"), entry.buf);
74                 strbuf_release(&entry);
75                 return -1;
76         }
77         strbuf_release(&entry);
78         return 0;
79 }
80
81 /*
82  * Try to remove the "submodule.<name>" section from .gitmodules where the given
83  * path is configured. Return 0 only if a .gitmodules file was found, a section
84  * with the correct path=<path> setting was found and we could remove it.
85  */
86 int remove_path_from_gitmodules(const char *path)
87 {
88         struct strbuf sect = STRBUF_INIT;
89         const struct submodule *submodule;
90
91         if (!file_exists(".gitmodules")) /* Do nothing without .gitmodules */
92                 return -1;
93
94         if (gitmodules_is_unmerged)
95                 die(_("Cannot change unmerged .gitmodules, resolve merge conflicts first"));
96
97         submodule = submodule_from_path(null_sha1, path);
98         if (!submodule || !submodule->name) {
99                 warning(_("Could not find section in .gitmodules where path=%s"), path);
100                 return -1;
101         }
102         strbuf_addstr(&sect, "submodule.");
103         strbuf_addstr(&sect, submodule->name);
104         if (git_config_rename_section_in_file(".gitmodules", sect.buf, NULL) < 0) {
105                 /* Maybe the user already did that, don't error out here */
106                 warning(_("Could not remove .gitmodules entry for %s"), path);
107                 strbuf_release(&sect);
108                 return -1;
109         }
110         strbuf_release(&sect);
111         return 0;
112 }
113
114 void stage_updated_gitmodules(void)
115 {
116         if (add_file_to_cache(".gitmodules", 0))
117                 die(_("staging updated .gitmodules failed"));
118 }
119
120 static int add_submodule_odb(const char *path)
121 {
122         struct strbuf objects_directory = STRBUF_INIT;
123         struct alternate_object_database *alt_odb;
124         int ret = 0;
125         const char *git_dir;
126
127         strbuf_addf(&objects_directory, "%s/.git", path);
128         git_dir = read_gitfile(objects_directory.buf);
129         if (git_dir) {
130                 strbuf_reset(&objects_directory);
131                 strbuf_addstr(&objects_directory, git_dir);
132         }
133         strbuf_addstr(&objects_directory, "/objects/");
134         if (!is_directory(objects_directory.buf)) {
135                 ret = -1;
136                 goto done;
137         }
138         /* avoid adding it twice */
139         for (alt_odb = alt_odb_list; alt_odb; alt_odb = alt_odb->next)
140                 if (alt_odb->name - alt_odb->base == objects_directory.len &&
141                                 !strncmp(alt_odb->base, objects_directory.buf,
142                                         objects_directory.len))
143                         goto done;
144
145         alt_odb = xmalloc(objects_directory.len + 42 + sizeof(*alt_odb));
146         alt_odb->next = alt_odb_list;
147         strcpy(alt_odb->base, objects_directory.buf);
148         alt_odb->name = alt_odb->base + objects_directory.len;
149         alt_odb->name[2] = '/';
150         alt_odb->name[40] = '\0';
151         alt_odb->name[41] = '\0';
152         alt_odb_list = alt_odb;
153
154         /* add possible alternates from the submodule */
155         read_info_alternates(objects_directory.buf, 0);
156         prepare_alt_odb();
157 done:
158         strbuf_release(&objects_directory);
159         return ret;
160 }
161
162 void set_diffopt_flags_from_submodule_config(struct diff_options *diffopt,
163                                              const char *path)
164 {
165         const struct submodule *submodule = submodule_from_path(null_sha1, path);
166         if (submodule) {
167                 if (submodule->ignore)
168                         handle_ignore_submodules_arg(diffopt, submodule->ignore);
169                 else if (gitmodules_is_unmerged)
170                         DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
171         }
172 }
173
174 int submodule_config(const char *var, const char *value, void *cb)
175 {
176         if (starts_with(var, "submodule."))
177                 return parse_submodule_config_option(var, value);
178         else if (!strcmp(var, "fetch.recursesubmodules")) {
179                 config_fetch_recurse_submodules = parse_fetch_recurse_submodules_arg(var, value);
180                 return 0;
181         }
182         return 0;
183 }
184
185 void gitmodules_config(void)
186 {
187         const char *work_tree = get_git_work_tree();
188         if (work_tree) {
189                 struct strbuf gitmodules_path = STRBUF_INIT;
190                 int pos;
191                 strbuf_addstr(&gitmodules_path, work_tree);
192                 strbuf_addstr(&gitmodules_path, "/.gitmodules");
193                 if (read_cache() < 0)
194                         die("index file corrupt");
195                 pos = cache_name_pos(".gitmodules", 11);
196                 if (pos < 0) { /* .gitmodules not found or isn't merged */
197                         pos = -1 - pos;
198                         if (active_nr > pos) {  /* there is a .gitmodules */
199                                 const struct cache_entry *ce = active_cache[pos];
200                                 if (ce_namelen(ce) == 11 &&
201                                     !memcmp(ce->name, ".gitmodules", 11))
202                                         gitmodules_is_unmerged = 1;
203                         }
204                 } else if (pos < active_nr) {
205                         struct stat st;
206                         if (lstat(".gitmodules", &st) == 0 &&
207                             ce_match_stat(active_cache[pos], &st, 0) & DATA_CHANGED)
208                                 gitmodules_is_modified = 1;
209                 }
210
211                 if (!gitmodules_is_unmerged)
212                         git_config_from_file(submodule_config, gitmodules_path.buf, NULL);
213                 strbuf_release(&gitmodules_path);
214         }
215 }
216
217 void handle_ignore_submodules_arg(struct diff_options *diffopt,
218                                   const char *arg)
219 {
220         DIFF_OPT_CLR(diffopt, IGNORE_SUBMODULES);
221         DIFF_OPT_CLR(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
222         DIFF_OPT_CLR(diffopt, IGNORE_DIRTY_SUBMODULES);
223
224         if (!strcmp(arg, "all"))
225                 DIFF_OPT_SET(diffopt, IGNORE_SUBMODULES);
226         else if (!strcmp(arg, "untracked"))
227                 DIFF_OPT_SET(diffopt, IGNORE_UNTRACKED_IN_SUBMODULES);
228         else if (!strcmp(arg, "dirty"))
229                 DIFF_OPT_SET(diffopt, IGNORE_DIRTY_SUBMODULES);
230         else if (strcmp(arg, "none"))
231                 die("bad --ignore-submodules argument: %s", arg);
232 }
233
234 static int prepare_submodule_summary(struct rev_info *rev, const char *path,
235                 struct commit *left, struct commit *right,
236                 int *fast_forward, int *fast_backward)
237 {
238         struct commit_list *merge_bases, *list;
239
240         init_revisions(rev, NULL);
241         setup_revisions(0, NULL, rev, NULL);
242         rev->left_right = 1;
243         rev->first_parent_only = 1;
244         left->object.flags |= SYMMETRIC_LEFT;
245         add_pending_object(rev, &left->object, path);
246         add_pending_object(rev, &right->object, path);
247         merge_bases = get_merge_bases(left, right);
248         if (merge_bases) {
249                 if (merge_bases->item == left)
250                         *fast_forward = 1;
251                 else if (merge_bases->item == right)
252                         *fast_backward = 1;
253         }
254         for (list = merge_bases; list; list = list->next) {
255                 list->item->object.flags |= UNINTERESTING;
256                 add_pending_object(rev, &list->item->object,
257                         sha1_to_hex(list->item->object.sha1));
258         }
259         return prepare_revision_walk(rev);
260 }
261
262 static void print_submodule_summary(struct rev_info *rev, FILE *f,
263                 const char *line_prefix,
264                 const char *del, const char *add, const char *reset)
265 {
266         static const char format[] = "  %m %s";
267         struct strbuf sb = STRBUF_INIT;
268         struct commit *commit;
269
270         while ((commit = get_revision(rev))) {
271                 struct pretty_print_context ctx = {0};
272                 ctx.date_mode = rev->date_mode;
273                 ctx.output_encoding = get_log_output_encoding();
274                 strbuf_setlen(&sb, 0);
275                 strbuf_addstr(&sb, line_prefix);
276                 if (commit->object.flags & SYMMETRIC_LEFT) {
277                         if (del)
278                                 strbuf_addstr(&sb, del);
279                 }
280                 else if (add)
281                         strbuf_addstr(&sb, add);
282                 format_commit_message(commit, format, &sb, &ctx);
283                 if (reset)
284                         strbuf_addstr(&sb, reset);
285                 strbuf_addch(&sb, '\n');
286                 fprintf(f, "%s", sb.buf);
287         }
288         strbuf_release(&sb);
289 }
290
291 void show_submodule_summary(FILE *f, const char *path,
292                 const char *line_prefix,
293                 unsigned char one[20], unsigned char two[20],
294                 unsigned dirty_submodule, const char *meta,
295                 const char *del, const char *add, const char *reset)
296 {
297         struct rev_info rev;
298         struct commit *left = NULL, *right = NULL;
299         const char *message = NULL;
300         struct strbuf sb = STRBUF_INIT;
301         int fast_forward = 0, fast_backward = 0;
302
303         if (is_null_sha1(two))
304                 message = "(submodule deleted)";
305         else if (add_submodule_odb(path))
306                 message = "(not checked out)";
307         else if (is_null_sha1(one))
308                 message = "(new submodule)";
309         else if (!(left = lookup_commit_reference(one)) ||
310                  !(right = lookup_commit_reference(two)))
311                 message = "(commits not present)";
312         else if (prepare_submodule_summary(&rev, path, left, right,
313                                            &fast_forward, &fast_backward))
314                 message = "(revision walker failed)";
315
316         if (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED)
317                 fprintf(f, "%sSubmodule %s contains untracked content\n",
318                         line_prefix, path);
319         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
320                 fprintf(f, "%sSubmodule %s contains modified content\n",
321                         line_prefix, path);
322
323         if (!hashcmp(one, two)) {
324                 strbuf_release(&sb);
325                 return;
326         }
327
328         strbuf_addf(&sb, "%s%sSubmodule %s %s..", line_prefix, meta, path,
329                         find_unique_abbrev(one, DEFAULT_ABBREV));
330         if (!fast_backward && !fast_forward)
331                 strbuf_addch(&sb, '.');
332         strbuf_addf(&sb, "%s", find_unique_abbrev(two, DEFAULT_ABBREV));
333         if (message)
334                 strbuf_addf(&sb, " %s%s\n", message, reset);
335         else
336                 strbuf_addf(&sb, "%s:%s\n", fast_backward ? " (rewind)" : "", reset);
337         fwrite(sb.buf, sb.len, 1, f);
338
339         if (!message) /* only NULL if we succeeded in setting up the walk */
340                 print_submodule_summary(&rev, f, line_prefix, del, add, reset);
341         if (left)
342                 clear_commit_marks(left, ~0);
343         if (right)
344                 clear_commit_marks(right, ~0);
345
346         strbuf_release(&sb);
347 }
348
349 void set_config_fetch_recurse_submodules(int value)
350 {
351         config_fetch_recurse_submodules = value;
352 }
353
354 static int has_remote(const char *refname, const struct object_id *oid,
355                       int flags, void *cb_data)
356 {
357         return 1;
358 }
359
360 static int submodule_needs_pushing(const char *path, const unsigned char sha1[20])
361 {
362         if (add_submodule_odb(path) || !lookup_commit_reference(sha1))
363                 return 0;
364
365         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
366                 struct child_process cp = CHILD_PROCESS_INIT;
367                 const char *argv[] = {"rev-list", NULL, "--not", "--remotes", "-n", "1" , NULL};
368                 struct strbuf buf = STRBUF_INIT;
369                 int needs_pushing = 0;
370
371                 argv[1] = sha1_to_hex(sha1);
372                 cp.argv = argv;
373                 cp.env = local_repo_env;
374                 cp.git_cmd = 1;
375                 cp.no_stdin = 1;
376                 cp.out = -1;
377                 cp.dir = path;
378                 if (start_command(&cp))
379                         die("Could not run 'git rev-list %s --not --remotes -n 1' command in submodule %s",
380                                 sha1_to_hex(sha1), path);
381                 if (strbuf_read(&buf, cp.out, 41))
382                         needs_pushing = 1;
383                 finish_command(&cp);
384                 close(cp.out);
385                 strbuf_release(&buf);
386                 return needs_pushing;
387         }
388
389         return 0;
390 }
391
392 static void collect_submodules_from_diff(struct diff_queue_struct *q,
393                                          struct diff_options *options,
394                                          void *data)
395 {
396         int i;
397         struct string_list *needs_pushing = data;
398
399         for (i = 0; i < q->nr; i++) {
400                 struct diff_filepair *p = q->queue[i];
401                 if (!S_ISGITLINK(p->two->mode))
402                         continue;
403                 if (submodule_needs_pushing(p->two->path, p->two->sha1))
404                         string_list_insert(needs_pushing, p->two->path);
405         }
406 }
407
408 static void find_unpushed_submodule_commits(struct commit *commit,
409                 struct string_list *needs_pushing)
410 {
411         struct rev_info rev;
412
413         init_revisions(&rev, NULL);
414         rev.diffopt.output_format |= DIFF_FORMAT_CALLBACK;
415         rev.diffopt.format_callback = collect_submodules_from_diff;
416         rev.diffopt.format_callback_data = needs_pushing;
417         diff_tree_combined_merge(commit, 1, &rev);
418 }
419
420 int find_unpushed_submodules(unsigned char new_sha1[20],
421                 const char *remotes_name, struct string_list *needs_pushing)
422 {
423         struct rev_info rev;
424         struct commit *commit;
425         const char *argv[] = {NULL, NULL, "--not", "NULL", NULL};
426         int argc = ARRAY_SIZE(argv) - 1;
427         char *sha1_copy;
428
429         struct strbuf remotes_arg = STRBUF_INIT;
430
431         strbuf_addf(&remotes_arg, "--remotes=%s", remotes_name);
432         init_revisions(&rev, NULL);
433         sha1_copy = xstrdup(sha1_to_hex(new_sha1));
434         argv[1] = sha1_copy;
435         argv[3] = remotes_arg.buf;
436         setup_revisions(argc, argv, &rev, NULL);
437         if (prepare_revision_walk(&rev))
438                 die("revision walk setup failed");
439
440         while ((commit = get_revision(&rev)) != NULL)
441                 find_unpushed_submodule_commits(commit, needs_pushing);
442
443         reset_revision_walk();
444         free(sha1_copy);
445         strbuf_release(&remotes_arg);
446
447         return needs_pushing->nr;
448 }
449
450 static int push_submodule(const char *path)
451 {
452         if (add_submodule_odb(path))
453                 return 1;
454
455         if (for_each_remote_ref_submodule(path, has_remote, NULL) > 0) {
456                 struct child_process cp = CHILD_PROCESS_INIT;
457                 const char *argv[] = {"push", NULL};
458
459                 cp.argv = argv;
460                 cp.env = local_repo_env;
461                 cp.git_cmd = 1;
462                 cp.no_stdin = 1;
463                 cp.dir = path;
464                 if (run_command(&cp))
465                         return 0;
466                 close(cp.out);
467         }
468
469         return 1;
470 }
471
472 int push_unpushed_submodules(unsigned char new_sha1[20], const char *remotes_name)
473 {
474         int i, ret = 1;
475         struct string_list needs_pushing = STRING_LIST_INIT_DUP;
476
477         if (!find_unpushed_submodules(new_sha1, remotes_name, &needs_pushing))
478                 return 1;
479
480         for (i = 0; i < needs_pushing.nr; i++) {
481                 const char *path = needs_pushing.items[i].string;
482                 fprintf(stderr, "Pushing submodule '%s'\n", path);
483                 if (!push_submodule(path)) {
484                         fprintf(stderr, "Unable to push submodule '%s'\n", path);
485                         ret = 0;
486                 }
487         }
488
489         string_list_clear(&needs_pushing, 0);
490
491         return ret;
492 }
493
494 static int is_submodule_commit_present(const char *path, unsigned char sha1[20])
495 {
496         int is_present = 0;
497         if (!add_submodule_odb(path) && lookup_commit_reference(sha1)) {
498                 /* Even if the submodule is checked out and the commit is
499                  * present, make sure it is reachable from a ref. */
500                 struct child_process cp = CHILD_PROCESS_INIT;
501                 const char *argv[] = {"rev-list", "-n", "1", NULL, "--not", "--all", NULL};
502                 struct strbuf buf = STRBUF_INIT;
503
504                 argv[3] = sha1_to_hex(sha1);
505                 cp.argv = argv;
506                 cp.env = local_repo_env;
507                 cp.git_cmd = 1;
508                 cp.no_stdin = 1;
509                 cp.dir = path;
510                 if (!capture_command(&cp, &buf, 1024) && !buf.len)
511                         is_present = 1;
512
513                 strbuf_release(&buf);
514         }
515         return is_present;
516 }
517
518 static void submodule_collect_changed_cb(struct diff_queue_struct *q,
519                                          struct diff_options *options,
520                                          void *data)
521 {
522         int i;
523         for (i = 0; i < q->nr; i++) {
524                 struct diff_filepair *p = q->queue[i];
525                 if (!S_ISGITLINK(p->two->mode))
526                         continue;
527
528                 if (S_ISGITLINK(p->one->mode)) {
529                         /* NEEDSWORK: We should honor the name configured in
530                          * the .gitmodules file of the commit we are examining
531                          * here to be able to correctly follow submodules
532                          * being moved around. */
533                         struct string_list_item *path;
534                         path = unsorted_string_list_lookup(&changed_submodule_paths, p->two->path);
535                         if (!path && !is_submodule_commit_present(p->two->path, p->two->sha1))
536                                 string_list_append(&changed_submodule_paths, xstrdup(p->two->path));
537                 } else {
538                         /* Submodule is new or was moved here */
539                         /* NEEDSWORK: When the .git directories of submodules
540                          * live inside the superprojects .git directory some
541                          * day we should fetch new submodules directly into
542                          * that location too when config or options request
543                          * that so they can be checked out from there. */
544                         continue;
545                 }
546         }
547 }
548
549 static int add_sha1_to_array(const char *ref, const struct object_id *oid,
550                              int flags, void *data)
551 {
552         sha1_array_append(data, oid->hash);
553         return 0;
554 }
555
556 void check_for_new_submodule_commits(unsigned char new_sha1[20])
557 {
558         if (!initialized_fetch_ref_tips) {
559                 for_each_ref(add_sha1_to_array, &ref_tips_before_fetch);
560                 initialized_fetch_ref_tips = 1;
561         }
562
563         sha1_array_append(&ref_tips_after_fetch, new_sha1);
564 }
565
566 static void add_sha1_to_argv(const unsigned char sha1[20], void *data)
567 {
568         argv_array_push(data, sha1_to_hex(sha1));
569 }
570
571 static void calculate_changed_submodule_paths(void)
572 {
573         struct rev_info rev;
574         struct commit *commit;
575         struct argv_array argv = ARGV_ARRAY_INIT;
576
577         /* No need to check if there are no submodules configured */
578         if (!submodule_from_path(NULL, NULL))
579                 return;
580
581         init_revisions(&rev, NULL);
582         argv_array_push(&argv, "--"); /* argv[0] program name */
583         sha1_array_for_each_unique(&ref_tips_after_fetch,
584                                    add_sha1_to_argv, &argv);
585         argv_array_push(&argv, "--not");
586         sha1_array_for_each_unique(&ref_tips_before_fetch,
587                                    add_sha1_to_argv, &argv);
588         setup_revisions(argv.argc, argv.argv, &rev, NULL);
589         if (prepare_revision_walk(&rev))
590                 die("revision walk setup failed");
591
592         /*
593          * Collect all submodules (whether checked out or not) for which new
594          * commits have been recorded upstream in "changed_submodule_paths".
595          */
596         while ((commit = get_revision(&rev))) {
597                 struct commit_list *parent = commit->parents;
598                 while (parent) {
599                         struct diff_options diff_opts;
600                         diff_setup(&diff_opts);
601                         DIFF_OPT_SET(&diff_opts, RECURSIVE);
602                         diff_opts.output_format |= DIFF_FORMAT_CALLBACK;
603                         diff_opts.format_callback = submodule_collect_changed_cb;
604                         diff_setup_done(&diff_opts);
605                         diff_tree_sha1(parent->item->object.sha1, commit->object.sha1, "", &diff_opts);
606                         diffcore_std(&diff_opts);
607                         diff_flush(&diff_opts);
608                         parent = parent->next;
609                 }
610         }
611
612         argv_array_clear(&argv);
613         sha1_array_clear(&ref_tips_before_fetch);
614         sha1_array_clear(&ref_tips_after_fetch);
615         initialized_fetch_ref_tips = 0;
616 }
617
618 int fetch_populated_submodules(const struct argv_array *options,
619                                const char *prefix, int command_line_option,
620                                int quiet)
621 {
622         int i, result = 0;
623         struct child_process cp = CHILD_PROCESS_INIT;
624         struct argv_array argv = ARGV_ARRAY_INIT;
625         const char *work_tree = get_git_work_tree();
626         if (!work_tree)
627                 goto out;
628
629         if (read_cache() < 0)
630                 die("index file corrupt");
631
632         argv_array_push(&argv, "fetch");
633         for (i = 0; i < options->argc; i++)
634                 argv_array_push(&argv, options->argv[i]);
635         argv_array_push(&argv, "--recurse-submodules-default");
636         /* default value, "--submodule-prefix" and its value are added later */
637
638         cp.env = local_repo_env;
639         cp.git_cmd = 1;
640         cp.no_stdin = 1;
641
642         calculate_changed_submodule_paths();
643
644         for (i = 0; i < active_nr; i++) {
645                 struct strbuf submodule_path = STRBUF_INIT;
646                 struct strbuf submodule_git_dir = STRBUF_INIT;
647                 struct strbuf submodule_prefix = STRBUF_INIT;
648                 const struct cache_entry *ce = active_cache[i];
649                 const char *git_dir, *default_argv;
650                 const struct submodule *submodule;
651
652                 if (!S_ISGITLINK(ce->ce_mode))
653                         continue;
654
655                 submodule = submodule_from_path(null_sha1, ce->name);
656                 if (!submodule)
657                         submodule = submodule_from_name(null_sha1, ce->name);
658
659                 default_argv = "yes";
660                 if (command_line_option == RECURSE_SUBMODULES_DEFAULT) {
661                         if (submodule &&
662                             submodule->fetch_recurse !=
663                                                 RECURSE_SUBMODULES_NONE) {
664                                 if (submodule->fetch_recurse ==
665                                                 RECURSE_SUBMODULES_OFF)
666                                         continue;
667                                 if (submodule->fetch_recurse ==
668                                                 RECURSE_SUBMODULES_ON_DEMAND) {
669                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
670                                                 continue;
671                                         default_argv = "on-demand";
672                                 }
673                         } else {
674                                 if ((config_fetch_recurse_submodules == RECURSE_SUBMODULES_OFF) ||
675                                     gitmodules_is_unmerged)
676                                         continue;
677                                 if (config_fetch_recurse_submodules == RECURSE_SUBMODULES_ON_DEMAND) {
678                                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
679                                                 continue;
680                                         default_argv = "on-demand";
681                                 }
682                         }
683                 } else if (command_line_option == RECURSE_SUBMODULES_ON_DEMAND) {
684                         if (!unsorted_string_list_lookup(&changed_submodule_paths, ce->name))
685                                 continue;
686                         default_argv = "on-demand";
687                 }
688
689                 strbuf_addf(&submodule_path, "%s/%s", work_tree, ce->name);
690                 strbuf_addf(&submodule_git_dir, "%s/.git", submodule_path.buf);
691                 strbuf_addf(&submodule_prefix, "%s%s/", prefix, ce->name);
692                 git_dir = read_gitfile(submodule_git_dir.buf);
693                 if (!git_dir)
694                         git_dir = submodule_git_dir.buf;
695                 if (is_directory(git_dir)) {
696                         if (!quiet)
697                                 printf("Fetching submodule %s%s\n", prefix, ce->name);
698                         cp.dir = submodule_path.buf;
699                         argv_array_push(&argv, default_argv);
700                         argv_array_push(&argv, "--submodule-prefix");
701                         argv_array_push(&argv, submodule_prefix.buf);
702                         cp.argv = argv.argv;
703                         if (run_command(&cp))
704                                 result = 1;
705                         argv_array_pop(&argv);
706                         argv_array_pop(&argv);
707                         argv_array_pop(&argv);
708                 }
709                 strbuf_release(&submodule_path);
710                 strbuf_release(&submodule_git_dir);
711                 strbuf_release(&submodule_prefix);
712         }
713         argv_array_clear(&argv);
714 out:
715         string_list_clear(&changed_submodule_paths, 1);
716         return result;
717 }
718
719 unsigned is_submodule_modified(const char *path, int ignore_untracked)
720 {
721         ssize_t len;
722         struct child_process cp = CHILD_PROCESS_INIT;
723         const char *argv[] = {
724                 "status",
725                 "--porcelain",
726                 NULL,
727                 NULL,
728         };
729         struct strbuf buf = STRBUF_INIT;
730         unsigned dirty_submodule = 0;
731         const char *line, *next_line;
732         const char *git_dir;
733
734         strbuf_addf(&buf, "%s/.git", path);
735         git_dir = read_gitfile(buf.buf);
736         if (!git_dir)
737                 git_dir = buf.buf;
738         if (!is_directory(git_dir)) {
739                 strbuf_release(&buf);
740                 /* The submodule is not checked out, so it is not modified */
741                 return 0;
742
743         }
744         strbuf_reset(&buf);
745
746         if (ignore_untracked)
747                 argv[2] = "-uno";
748
749         cp.argv = argv;
750         cp.env = local_repo_env;
751         cp.git_cmd = 1;
752         cp.no_stdin = 1;
753         cp.out = -1;
754         cp.dir = path;
755         if (start_command(&cp))
756                 die("Could not run 'git status --porcelain' in submodule %s", path);
757
758         len = strbuf_read(&buf, cp.out, 1024);
759         line = buf.buf;
760         while (len > 2) {
761                 if ((line[0] == '?') && (line[1] == '?')) {
762                         dirty_submodule |= DIRTY_SUBMODULE_UNTRACKED;
763                         if (dirty_submodule & DIRTY_SUBMODULE_MODIFIED)
764                                 break;
765                 } else {
766                         dirty_submodule |= DIRTY_SUBMODULE_MODIFIED;
767                         if (ignore_untracked ||
768                             (dirty_submodule & DIRTY_SUBMODULE_UNTRACKED))
769                                 break;
770                 }
771                 next_line = strchr(line, '\n');
772                 if (!next_line)
773                         break;
774                 next_line++;
775                 len -= (next_line - line);
776                 line = next_line;
777         }
778         close(cp.out);
779
780         if (finish_command(&cp))
781                 die("'git status --porcelain' failed in submodule %s", path);
782
783         strbuf_release(&buf);
784         return dirty_submodule;
785 }
786
787 int submodule_uses_gitfile(const char *path)
788 {
789         struct child_process cp = CHILD_PROCESS_INIT;
790         const char *argv[] = {
791                 "submodule",
792                 "foreach",
793                 "--quiet",
794                 "--recursive",
795                 "test -f .git",
796                 NULL,
797         };
798         struct strbuf buf = STRBUF_INIT;
799         const char *git_dir;
800
801         strbuf_addf(&buf, "%s/.git", path);
802         git_dir = read_gitfile(buf.buf);
803         if (!git_dir) {
804                 strbuf_release(&buf);
805                 return 0;
806         }
807         strbuf_release(&buf);
808
809         /* Now test that all nested submodules use a gitfile too */
810         cp.argv = argv;
811         cp.env = local_repo_env;
812         cp.git_cmd = 1;
813         cp.no_stdin = 1;
814         cp.no_stderr = 1;
815         cp.no_stdout = 1;
816         cp.dir = path;
817         if (run_command(&cp))
818                 return 0;
819
820         return 1;
821 }
822
823 int ok_to_remove_submodule(const char *path)
824 {
825         ssize_t len;
826         struct child_process cp = CHILD_PROCESS_INIT;
827         const char *argv[] = {
828                 "status",
829                 "--porcelain",
830                 "-u",
831                 "--ignore-submodules=none",
832                 NULL,
833         };
834         struct strbuf buf = STRBUF_INIT;
835         int ok_to_remove = 1;
836
837         if (!file_exists(path) || is_empty_dir(path))
838                 return 1;
839
840         if (!submodule_uses_gitfile(path))
841                 return 0;
842
843         cp.argv = argv;
844         cp.env = local_repo_env;
845         cp.git_cmd = 1;
846         cp.no_stdin = 1;
847         cp.out = -1;
848         cp.dir = path;
849         if (start_command(&cp))
850                 die("Could not run 'git status --porcelain -uall --ignore-submodules=none' in submodule %s", path);
851
852         len = strbuf_read(&buf, cp.out, 1024);
853         if (len > 2)
854                 ok_to_remove = 0;
855         close(cp.out);
856
857         if (finish_command(&cp))
858                 die("'git status --porcelain -uall --ignore-submodules=none' failed in submodule %s", path);
859
860         strbuf_release(&buf);
861         return ok_to_remove;
862 }
863
864 static int find_first_merges(struct object_array *result, const char *path,
865                 struct commit *a, struct commit *b)
866 {
867         int i, j;
868         struct object_array merges = OBJECT_ARRAY_INIT;
869         struct commit *commit;
870         int contains_another;
871
872         char merged_revision[42];
873         const char *rev_args[] = { "rev-list", "--merges", "--ancestry-path",
874                                    "--all", merged_revision, NULL };
875         struct rev_info revs;
876         struct setup_revision_opt rev_opts;
877
878         memset(result, 0, sizeof(struct object_array));
879         memset(&rev_opts, 0, sizeof(rev_opts));
880
881         /* get all revisions that merge commit a */
882         snprintf(merged_revision, sizeof(merged_revision), "^%s",
883                         sha1_to_hex(a->object.sha1));
884         init_revisions(&revs, NULL);
885         rev_opts.submodule = path;
886         setup_revisions(ARRAY_SIZE(rev_args)-1, rev_args, &revs, &rev_opts);
887
888         /* save all revisions from the above list that contain b */
889         if (prepare_revision_walk(&revs))
890                 die("revision walk setup failed");
891         while ((commit = get_revision(&revs)) != NULL) {
892                 struct object *o = &(commit->object);
893                 if (in_merge_bases(b, commit))
894                         add_object_array(o, NULL, &merges);
895         }
896         reset_revision_walk();
897
898         /* Now we've got all merges that contain a and b. Prune all
899          * merges that contain another found merge and save them in
900          * result.
901          */
902         for (i = 0; i < merges.nr; i++) {
903                 struct commit *m1 = (struct commit *) merges.objects[i].item;
904
905                 contains_another = 0;
906                 for (j = 0; j < merges.nr; j++) {
907                         struct commit *m2 = (struct commit *) merges.objects[j].item;
908                         if (i != j && in_merge_bases(m2, m1)) {
909                                 contains_another = 1;
910                                 break;
911                         }
912                 }
913
914                 if (!contains_another)
915                         add_object_array(merges.objects[i].item, NULL, result);
916         }
917
918         free(merges.objects);
919         return result->nr;
920 }
921
922 static void print_commit(struct commit *commit)
923 {
924         struct strbuf sb = STRBUF_INIT;
925         struct pretty_print_context ctx = {0};
926         ctx.date_mode.type = DATE_NORMAL;
927         format_commit_message(commit, " %h: %m %s", &sb, &ctx);
928         fprintf(stderr, "%s\n", sb.buf);
929         strbuf_release(&sb);
930 }
931
932 #define MERGE_WARNING(path, msg) \
933         warning("Failed to merge submodule %s (%s)", path, msg);
934
935 int merge_submodule(unsigned char result[20], const char *path,
936                     const unsigned char base[20], const unsigned char a[20],
937                     const unsigned char b[20], int search)
938 {
939         struct commit *commit_base, *commit_a, *commit_b;
940         int parent_count;
941         struct object_array merges;
942
943         int i;
944
945         /* store a in result in case we fail */
946         hashcpy(result, a);
947
948         /* we can not handle deletion conflicts */
949         if (is_null_sha1(base))
950                 return 0;
951         if (is_null_sha1(a))
952                 return 0;
953         if (is_null_sha1(b))
954                 return 0;
955
956         if (add_submodule_odb(path)) {
957                 MERGE_WARNING(path, "not checked out");
958                 return 0;
959         }
960
961         if (!(commit_base = lookup_commit_reference(base)) ||
962             !(commit_a = lookup_commit_reference(a)) ||
963             !(commit_b = lookup_commit_reference(b))) {
964                 MERGE_WARNING(path, "commits not present");
965                 return 0;
966         }
967
968         /* check whether both changes are forward */
969         if (!in_merge_bases(commit_base, commit_a) ||
970             !in_merge_bases(commit_base, commit_b)) {
971                 MERGE_WARNING(path, "commits don't follow merge-base");
972                 return 0;
973         }
974
975         /* Case #1: a is contained in b or vice versa */
976         if (in_merge_bases(commit_a, commit_b)) {
977                 hashcpy(result, b);
978                 return 1;
979         }
980         if (in_merge_bases(commit_b, commit_a)) {
981                 hashcpy(result, a);
982                 return 1;
983         }
984
985         /*
986          * Case #2: There are one or more merges that contain a and b in
987          * the submodule. If there is only one, then present it as a
988          * suggestion to the user, but leave it marked unmerged so the
989          * user needs to confirm the resolution.
990          */
991
992         /* Skip the search if makes no sense to the calling context.  */
993         if (!search)
994                 return 0;
995
996         /* find commit which merges them */
997         parent_count = find_first_merges(&merges, path, commit_a, commit_b);
998         switch (parent_count) {
999         case 0:
1000                 MERGE_WARNING(path, "merge following commits not found");
1001                 break;
1002
1003         case 1:
1004                 MERGE_WARNING(path, "not fast-forward");
1005                 fprintf(stderr, "Found a possible merge resolution "
1006                                 "for the submodule:\n");
1007                 print_commit((struct commit *) merges.objects[0].item);
1008                 fprintf(stderr,
1009                         "If this is correct simply add it to the index "
1010                         "for example\n"
1011                         "by using:\n\n"
1012                         "  git update-index --cacheinfo 160000 %s \"%s\"\n\n"
1013                         "which will accept this suggestion.\n",
1014                         sha1_to_hex(merges.objects[0].item->sha1), path);
1015                 break;
1016
1017         default:
1018                 MERGE_WARNING(path, "multiple merges found");
1019                 for (i = 0; i < merges.nr; i++)
1020                         print_commit((struct commit *) merges.objects[i].item);
1021         }
1022
1023         free(merges.objects);
1024         return 0;
1025 }
1026
1027 /* Update gitfile and core.worktree setting to connect work tree and git dir */
1028 void connect_work_tree_and_git_dir(const char *work_tree, const char *git_dir)
1029 {
1030         struct strbuf file_name = STRBUF_INIT;
1031         struct strbuf rel_path = STRBUF_INIT;
1032         const char *real_work_tree = xstrdup(real_path(work_tree));
1033
1034         /* Update gitfile */
1035         strbuf_addf(&file_name, "%s/.git", work_tree);
1036         write_file(file_name.buf, 1, "gitdir: %s\n",
1037                    relative_path(git_dir, real_work_tree, &rel_path));
1038
1039         /* Update core.worktree setting */
1040         strbuf_reset(&file_name);
1041         strbuf_addf(&file_name, "%s/config", git_dir);
1042         if (git_config_set_in_file(file_name.buf, "core.worktree",
1043                                    relative_path(real_work_tree, git_dir,
1044                                                  &rel_path)))
1045                 die(_("Could not set core.worktree in %s"),
1046                     file_name.buf);
1047
1048         strbuf_release(&file_name);
1049         strbuf_release(&rel_path);
1050         free((void *)real_work_tree);
1051 }