Move read_in_full() and write_in_full() to wrapper.c
[git.git] / builtin-merge.c
blobe97c79e60cdb8227ad682a3927ae955005cbe1f3
1 /*
2 * Builtin "git merge"
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
6 * Based on git-merge.sh by Junio C Hamano.
7 */
9 #include "cache.h"
10 #include "parse-options.h"
11 #include "builtin.h"
12 #include "run-command.h"
13 #include "diff.h"
14 #include "refs.h"
15 #include "commit.h"
16 #include "diffcore.h"
17 #include "revision.h"
18 #include "unpack-trees.h"
19 #include "cache-tree.h"
20 #include "dir.h"
21 #include "utf8.h"
22 #include "log-tree.h"
23 #include "color.h"
24 #include "rerere.h"
26 #define DEFAULT_TWOHEAD (1<<0)
27 #define DEFAULT_OCTOPUS (1<<1)
28 #define NO_FAST_FORWARD (1<<2)
29 #define NO_TRIVIAL (1<<3)
31 struct strategy {
32 const char *name;
33 unsigned attr;
36 static const char * const builtin_merge_usage[] = {
37 "git-merge [options] <remote>...",
38 "git-merge [options] <msg> HEAD <remote>",
39 NULL
42 static int show_diffstat = 1, option_log, squash;
43 static int option_commit = 1, allow_fast_forward = 1;
44 static int allow_trivial = 1, have_message;
45 static struct strbuf merge_msg;
46 static struct commit_list *remoteheads;
47 static unsigned char head[20], stash[20];
48 static struct strategy **use_strategies;
49 static size_t use_strategies_nr, use_strategies_alloc;
50 static const char *branch;
52 static struct strategy all_strategy[] = {
53 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
54 { "octopus", DEFAULT_OCTOPUS },
55 { "resolve", 0 },
56 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
57 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
60 static const char *pull_twohead, *pull_octopus;
62 static int option_parse_message(const struct option *opt,
63 const char *arg, int unset)
65 struct strbuf *buf = opt->value;
67 if (unset)
68 strbuf_setlen(buf, 0);
69 else if (arg) {
70 strbuf_addf(buf, "%s\n\n", arg);
71 have_message = 1;
72 } else
73 return error("switch `m' requires a value");
74 return 0;
77 static struct strategy *get_strategy(const char *name)
79 int i;
81 if (!name)
82 return NULL;
84 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
85 if (!strcmp(name, all_strategy[i].name))
86 return &all_strategy[i];
87 return NULL;
90 static void append_strategy(struct strategy *s)
92 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
93 use_strategies[use_strategies_nr++] = s;
96 static int option_parse_strategy(const struct option *opt,
97 const char *name, int unset)
99 int i;
100 struct strategy *s;
102 if (unset)
103 return 0;
105 s = get_strategy(name);
107 if (s)
108 append_strategy(s);
109 else {
110 struct strbuf err;
111 strbuf_init(&err, 0);
112 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
113 strbuf_addf(&err, " %s", all_strategy[i].name);
114 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
115 fprintf(stderr, "Available strategies are:%s.\n", err.buf);
116 exit(1);
118 return 0;
121 static int option_parse_n(const struct option *opt,
122 const char *arg, int unset)
124 show_diffstat = unset;
125 return 0;
128 static struct option builtin_merge_options[] = {
129 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
130 "do not show a diffstat at the end of the merge",
131 PARSE_OPT_NOARG, option_parse_n },
132 OPT_BOOLEAN(0, "stat", &show_diffstat,
133 "show a diffstat at the end of the merge"),
134 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
135 OPT_BOOLEAN(0, "log", &option_log,
136 "add list of one-line log to merge commit message"),
137 OPT_BOOLEAN(0, "squash", &squash,
138 "create a single commit instead of doing a merge"),
139 OPT_BOOLEAN(0, "commit", &option_commit,
140 "perform a commit if the merge succeeds (default)"),
141 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
142 "allow fast forward (default)"),
143 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
144 "merge strategy to use", option_parse_strategy),
145 OPT_CALLBACK('m', "message", &merge_msg, "message",
146 "message to be used for the merge commit (if any)",
147 option_parse_message),
148 OPT_END()
151 /* Cleans up metadata that is uninteresting after a succeeded merge. */
152 static void drop_save(void)
154 unlink(git_path("MERGE_HEAD"));
155 unlink(git_path("MERGE_MSG"));
158 static void save_state(void)
160 int len;
161 struct child_process cp;
162 struct strbuf buffer = STRBUF_INIT;
163 const char *argv[] = {"stash", "create", NULL};
165 memset(&cp, 0, sizeof(cp));
166 cp.argv = argv;
167 cp.out = -1;
168 cp.git_cmd = 1;
170 if (start_command(&cp))
171 die("could not run stash.");
172 len = strbuf_read(&buffer, cp.out, 1024);
173 close(cp.out);
175 if (finish_command(&cp) || len < 0)
176 die("stash failed");
177 else if (!len)
178 return;
179 strbuf_setlen(&buffer, buffer.len-1);
180 if (get_sha1(buffer.buf, stash))
181 die("not a valid object: %s", buffer.buf);
184 static void reset_hard(unsigned const char *sha1, int verbose)
186 int i = 0;
187 const char *args[6];
189 args[i++] = "read-tree";
190 if (verbose)
191 args[i++] = "-v";
192 args[i++] = "--reset";
193 args[i++] = "-u";
194 args[i++] = sha1_to_hex(sha1);
195 args[i] = NULL;
197 if (run_command_v_opt(args, RUN_GIT_CMD))
198 die("read-tree failed");
201 static void restore_state(void)
203 struct strbuf sb;
204 const char *args[] = { "stash", "apply", NULL, NULL };
206 if (is_null_sha1(stash))
207 return;
209 reset_hard(head, 1);
211 strbuf_init(&sb, 0);
212 args[2] = sha1_to_hex(stash);
215 * It is OK to ignore error here, for example when there was
216 * nothing to restore.
218 run_command_v_opt(args, RUN_GIT_CMD);
220 strbuf_release(&sb);
221 refresh_cache(REFRESH_QUIET);
224 /* This is called when no merge was necessary. */
225 static void finish_up_to_date(const char *msg)
227 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
228 drop_save();
231 static void squash_message(void)
233 struct rev_info rev;
234 struct commit *commit;
235 struct strbuf out;
236 struct commit_list *j;
237 int fd;
239 printf("Squash commit -- not updating HEAD\n");
240 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
241 if (fd < 0)
242 die("Could not write to %s", git_path("SQUASH_MSG"));
244 init_revisions(&rev, NULL);
245 rev.ignore_merges = 1;
246 rev.commit_format = CMIT_FMT_MEDIUM;
248 commit = lookup_commit(head);
249 commit->object.flags |= UNINTERESTING;
250 add_pending_object(&rev, &commit->object, NULL);
252 for (j = remoteheads; j; j = j->next)
253 add_pending_object(&rev, &j->item->object, NULL);
255 setup_revisions(0, NULL, &rev, NULL);
256 if (prepare_revision_walk(&rev))
257 die("revision walk setup failed");
259 strbuf_init(&out, 0);
260 strbuf_addstr(&out, "Squashed commit of the following:\n");
261 while ((commit = get_revision(&rev)) != NULL) {
262 strbuf_addch(&out, '\n');
263 strbuf_addf(&out, "commit %s\n",
264 sha1_to_hex(commit->object.sha1));
265 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
266 NULL, NULL, rev.date_mode, 0);
268 write(fd, out.buf, out.len);
269 close(fd);
270 strbuf_release(&out);
273 static int run_hook(const char *name)
275 struct child_process hook;
276 const char *argv[3], *env[2];
277 char index[PATH_MAX];
279 argv[0] = git_path("hooks/%s", name);
280 if (access(argv[0], X_OK) < 0)
281 return 0;
283 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
284 env[0] = index;
285 env[1] = NULL;
287 if (squash)
288 argv[1] = "1";
289 else
290 argv[1] = "0";
291 argv[2] = NULL;
293 memset(&hook, 0, sizeof(hook));
294 hook.argv = argv;
295 hook.no_stdin = 1;
296 hook.stdout_to_stderr = 1;
297 hook.env = env;
299 return run_command(&hook);
302 static void finish(const unsigned char *new_head, const char *msg)
304 struct strbuf reflog_message;
306 strbuf_init(&reflog_message, 0);
307 if (!msg)
308 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
309 else {
310 printf("%s\n", msg);
311 strbuf_addf(&reflog_message, "%s: %s",
312 getenv("GIT_REFLOG_ACTION"), msg);
314 if (squash) {
315 squash_message();
316 } else {
317 if (!merge_msg.len)
318 printf("No merge message -- not updating HEAD\n");
319 else {
320 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
321 update_ref(reflog_message.buf, "HEAD",
322 new_head, head, 0,
323 DIE_ON_ERR);
325 * We ignore errors in 'gc --auto', since the
326 * user should see them.
328 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
331 if (new_head && show_diffstat) {
332 struct diff_options opts;
333 diff_setup(&opts);
334 opts.output_format |=
335 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
336 opts.detect_rename = DIFF_DETECT_RENAME;
337 if (diff_use_color_default > 0)
338 DIFF_OPT_SET(&opts, COLOR_DIFF);
339 if (diff_setup_done(&opts) < 0)
340 die("diff_setup_done failed");
341 diff_tree_sha1(head, new_head, "", &opts);
342 diffcore_std(&opts);
343 diff_flush(&opts);
346 /* Run a post-merge hook */
347 run_hook("post-merge");
349 strbuf_release(&reflog_message);
352 /* Get the name for the merge commit's message. */
353 static void merge_name(const char *remote, struct strbuf *msg)
355 struct object *remote_head;
356 unsigned char branch_head[20], buf_sha[20];
357 struct strbuf buf;
358 const char *ptr;
359 int len, early;
361 memset(branch_head, 0, sizeof(branch_head));
362 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
363 if (!remote_head)
364 die("'%s' does not point to a commit", remote);
366 strbuf_init(&buf, 0);
367 strbuf_addstr(&buf, "refs/heads/");
368 strbuf_addstr(&buf, remote);
369 resolve_ref(buf.buf, branch_head, 0, 0);
371 if (!hashcmp(remote_head->sha1, branch_head)) {
372 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
373 sha1_to_hex(branch_head), remote);
374 return;
377 /* See if remote matches <name>^^^.. or <name>~<number> */
378 for (len = 0, ptr = remote + strlen(remote);
379 remote < ptr && ptr[-1] == '^';
380 ptr--)
381 len++;
382 if (len)
383 early = 1;
384 else {
385 early = 0;
386 ptr = strrchr(remote, '~');
387 if (ptr) {
388 int seen_nonzero = 0;
390 len++; /* count ~ */
391 while (*++ptr && isdigit(*ptr)) {
392 seen_nonzero |= (*ptr != '0');
393 len++;
395 if (*ptr)
396 len = 0; /* not ...~<number> */
397 else if (seen_nonzero)
398 early = 1;
399 else if (len == 1)
400 early = 1; /* "name~" is "name~1"! */
403 if (len) {
404 struct strbuf truname = STRBUF_INIT;
405 strbuf_addstr(&truname, "refs/heads/");
406 strbuf_addstr(&truname, remote);
407 strbuf_setlen(&truname, len+11);
408 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
409 strbuf_addf(msg,
410 "%s\t\tbranch '%s'%s of .\n",
411 sha1_to_hex(remote_head->sha1),
412 truname.buf,
413 (early ? " (early part)" : ""));
414 return;
418 if (!strcmp(remote, "FETCH_HEAD") &&
419 !access(git_path("FETCH_HEAD"), R_OK)) {
420 FILE *fp;
421 struct strbuf line;
422 char *ptr;
424 strbuf_init(&line, 0);
425 fp = fopen(git_path("FETCH_HEAD"), "r");
426 if (!fp)
427 die("could not open %s for reading: %s",
428 git_path("FETCH_HEAD"), strerror(errno));
429 strbuf_getline(&line, fp, '\n');
430 fclose(fp);
431 ptr = strstr(line.buf, "\tnot-for-merge\t");
432 if (ptr)
433 strbuf_remove(&line, ptr-line.buf+1, 13);
434 strbuf_addbuf(msg, &line);
435 strbuf_release(&line);
436 return;
438 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
439 sha1_to_hex(remote_head->sha1), remote);
442 int git_merge_config(const char *k, const char *v, void *cb)
444 if (branch && !prefixcmp(k, "branch.") &&
445 !prefixcmp(k + 7, branch) &&
446 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
447 const char **argv;
448 int argc;
449 char *buf;
451 buf = xstrdup(v);
452 argc = split_cmdline(buf, &argv);
453 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
454 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
455 argc++;
456 parse_options(argc, argv, builtin_merge_options,
457 builtin_merge_usage, 0);
458 free(buf);
461 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
462 show_diffstat = git_config_bool(k, v);
463 else if (!strcmp(k, "pull.twohead"))
464 return git_config_string(&pull_twohead, k, v);
465 else if (!strcmp(k, "pull.octopus"))
466 return git_config_string(&pull_octopus, k, v);
467 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
468 option_log = git_config_bool(k, v);
469 return git_diff_ui_config(k, v, cb);
472 static int read_tree_trivial(unsigned char *common, unsigned char *head,
473 unsigned char *one)
475 int i, nr_trees = 0;
476 struct tree *trees[MAX_UNPACK_TREES];
477 struct tree_desc t[MAX_UNPACK_TREES];
478 struct unpack_trees_options opts;
480 memset(&opts, 0, sizeof(opts));
481 opts.head_idx = 2;
482 opts.src_index = &the_index;
483 opts.dst_index = &the_index;
484 opts.update = 1;
485 opts.verbose_update = 1;
486 opts.trivial_merges_only = 1;
487 opts.merge = 1;
488 trees[nr_trees] = parse_tree_indirect(common);
489 if (!trees[nr_trees++])
490 return -1;
491 trees[nr_trees] = parse_tree_indirect(head);
492 if (!trees[nr_trees++])
493 return -1;
494 trees[nr_trees] = parse_tree_indirect(one);
495 if (!trees[nr_trees++])
496 return -1;
497 opts.fn = threeway_merge;
498 cache_tree_free(&active_cache_tree);
499 for (i = 0; i < nr_trees; i++) {
500 parse_tree(trees[i]);
501 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
503 if (unpack_trees(nr_trees, t, &opts))
504 return -1;
505 return 0;
508 static void write_tree_trivial(unsigned char *sha1)
510 if (write_cache_as_tree(sha1, 0, NULL))
511 die("git write-tree failed to write a tree");
514 static int try_merge_strategy(const char *strategy, struct commit_list *common,
515 const char *head_arg)
517 const char **args;
518 int i = 0, ret;
519 struct commit_list *j;
520 struct strbuf buf;
522 args = xmalloc((4 + commit_list_count(common) +
523 commit_list_count(remoteheads)) * sizeof(char *));
524 strbuf_init(&buf, 0);
525 strbuf_addf(&buf, "merge-%s", strategy);
526 args[i++] = buf.buf;
527 for (j = common; j; j = j->next)
528 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
529 args[i++] = "--";
530 args[i++] = head_arg;
531 for (j = remoteheads; j; j = j->next)
532 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
533 args[i] = NULL;
534 ret = run_command_v_opt(args, RUN_GIT_CMD);
535 strbuf_release(&buf);
536 i = 1;
537 for (j = common; j; j = j->next)
538 free((void *)args[i++]);
539 i += 2;
540 for (j = remoteheads; j; j = j->next)
541 free((void *)args[i++]);
542 free(args);
543 return -ret;
546 static void count_diff_files(struct diff_queue_struct *q,
547 struct diff_options *opt, void *data)
549 int *count = data;
551 (*count) += q->nr;
554 static int count_unmerged_entries(void)
556 const struct index_state *state = &the_index;
557 int i, ret = 0;
559 for (i = 0; i < state->cache_nr; i++)
560 if (ce_stage(state->cache[i]))
561 ret++;
563 return ret;
566 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
568 struct tree *trees[MAX_UNPACK_TREES];
569 struct unpack_trees_options opts;
570 struct tree_desc t[MAX_UNPACK_TREES];
571 int i, fd, nr_trees = 0;
572 struct dir_struct dir;
573 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
575 if (read_cache_unmerged())
576 die("you need to resolve your current index first");
578 fd = hold_locked_index(lock_file, 1);
580 memset(&trees, 0, sizeof(trees));
581 memset(&opts, 0, sizeof(opts));
582 memset(&t, 0, sizeof(t));
583 dir.show_ignored = 1;
584 dir.exclude_per_dir = ".gitignore";
585 opts.dir = &dir;
587 opts.head_idx = 1;
588 opts.src_index = &the_index;
589 opts.dst_index = &the_index;
590 opts.update = 1;
591 opts.verbose_update = 1;
592 opts.merge = 1;
593 opts.fn = twoway_merge;
595 trees[nr_trees] = parse_tree_indirect(head);
596 if (!trees[nr_trees++])
597 return -1;
598 trees[nr_trees] = parse_tree_indirect(remote);
599 if (!trees[nr_trees++])
600 return -1;
601 for (i = 0; i < nr_trees; i++) {
602 parse_tree(trees[i]);
603 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
605 if (unpack_trees(nr_trees, t, &opts))
606 return -1;
607 if (write_cache(fd, active_cache, active_nr) ||
608 commit_locked_index(lock_file))
609 die("unable to write new index file");
610 return 0;
613 static void split_merge_strategies(const char *string, struct strategy **list,
614 int *nr, int *alloc)
616 char *p, *q, *buf;
618 if (!string)
619 return;
621 buf = xstrdup(string);
622 q = buf;
623 for (;;) {
624 p = strchr(q, ' ');
625 if (!p) {
626 ALLOC_GROW(*list, *nr + 1, *alloc);
627 (*list)[(*nr)++].name = xstrdup(q);
628 free(buf);
629 return;
630 } else {
631 *p = '\0';
632 ALLOC_GROW(*list, *nr + 1, *alloc);
633 (*list)[(*nr)++].name = xstrdup(q);
634 q = ++p;
639 static void add_strategies(const char *string, unsigned attr)
641 struct strategy *list = NULL;
642 int list_alloc = 0, list_nr = 0, i;
644 memset(&list, 0, sizeof(list));
645 split_merge_strategies(string, &list, &list_nr, &list_alloc);
646 if (list != NULL) {
647 for (i = 0; i < list_nr; i++) {
648 struct strategy *s;
650 s = get_strategy(list[i].name);
651 if (s)
652 append_strategy(s);
654 return;
656 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
657 if (all_strategy[i].attr & attr)
658 append_strategy(&all_strategy[i]);
662 static int merge_trivial(void)
664 unsigned char result_tree[20], result_commit[20];
665 struct commit_list parent;
667 write_tree_trivial(result_tree);
668 printf("Wonderful.\n");
669 parent.item = remoteheads->item;
670 parent.next = NULL;
671 commit_tree(merge_msg.buf, result_tree, &parent, result_commit);
672 finish(result_commit, "In-index merge");
673 drop_save();
674 return 0;
677 static int finish_automerge(struct commit_list *common,
678 unsigned char *result_tree,
679 const char *wt_strategy)
681 struct commit_list *parents = NULL, *j;
682 struct strbuf buf = STRBUF_INIT;
683 unsigned char result_commit[20];
685 free_commit_list(common);
686 if (allow_fast_forward) {
687 parents = remoteheads;
688 commit_list_insert(lookup_commit(head), &parents);
689 parents = reduce_heads(parents);
690 } else {
691 struct commit_list **pptr = &parents;
693 pptr = &commit_list_insert(lookup_commit(head),
694 pptr)->next;
695 for (j = remoteheads; j; j = j->next)
696 pptr = &commit_list_insert(j->item, pptr)->next;
698 free_commit_list(remoteheads);
699 strbuf_addch(&merge_msg, '\n');
700 commit_tree(merge_msg.buf, result_tree, parents, result_commit);
701 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
702 finish(result_commit, buf.buf);
703 strbuf_release(&buf);
704 drop_save();
705 return 0;
708 static int suggest_conflicts(void)
710 FILE *fp;
711 int pos;
713 fp = fopen(git_path("MERGE_MSG"), "a");
714 if (!fp)
715 die("Could open %s for writing", git_path("MERGE_MSG"));
716 fprintf(fp, "\nConflicts:\n");
717 for (pos = 0; pos < active_nr; pos++) {
718 struct cache_entry *ce = active_cache[pos];
720 if (ce_stage(ce)) {
721 fprintf(fp, "\t%s\n", ce->name);
722 while (pos + 1 < active_nr &&
723 !strcmp(ce->name,
724 active_cache[pos + 1]->name))
725 pos++;
728 fclose(fp);
729 rerere();
730 printf("Automatic merge failed; "
731 "fix conflicts and then commit the result.\n");
732 return 1;
735 static struct commit *is_old_style_invocation(int argc, const char **argv)
737 struct commit *second_token = NULL;
738 if (argc > 1) {
739 unsigned char second_sha1[20];
741 if (get_sha1(argv[1], second_sha1))
742 return NULL;
743 second_token = lookup_commit_reference_gently(second_sha1, 0);
744 if (!second_token)
745 die("'%s' is not a commit", argv[1]);
746 if (hashcmp(second_token->object.sha1, head))
747 return NULL;
749 return second_token;
752 static int evaluate_result(void)
754 int cnt = 0;
755 struct rev_info rev;
757 if (read_cache() < 0)
758 die("failed to read the cache");
760 /* Check how many files differ. */
761 init_revisions(&rev, "");
762 setup_revisions(0, NULL, &rev, NULL);
763 rev.diffopt.output_format |=
764 DIFF_FORMAT_CALLBACK;
765 rev.diffopt.format_callback = count_diff_files;
766 rev.diffopt.format_callback_data = &cnt;
767 run_diff_files(&rev, 0);
770 * Check how many unmerged entries are
771 * there.
773 cnt += count_unmerged_entries();
775 return cnt;
778 int cmd_merge(int argc, const char **argv, const char *prefix)
780 unsigned char result_tree[20];
781 struct strbuf buf;
782 const char *head_arg;
783 int flag, head_invalid = 0, i;
784 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
785 struct commit_list *common = NULL;
786 const char *best_strategy = NULL, *wt_strategy = NULL;
787 struct commit_list **remotes = &remoteheads;
789 setup_work_tree();
790 if (unmerged_cache())
791 die("You are in the middle of a conflicted merge.");
794 * Check if we are _not_ on a detached HEAD, i.e. if there is a
795 * current branch.
797 branch = resolve_ref("HEAD", head, 0, &flag);
798 if (branch && !prefixcmp(branch, "refs/heads/"))
799 branch += 11;
800 if (is_null_sha1(head))
801 head_invalid = 1;
803 git_config(git_merge_config, NULL);
805 /* for color.ui */
806 if (diff_use_color_default == -1)
807 diff_use_color_default = git_use_color_default;
809 argc = parse_options(argc, argv, builtin_merge_options,
810 builtin_merge_usage, 0);
812 if (squash) {
813 if (!allow_fast_forward)
814 die("You cannot combine --squash with --no-ff.");
815 option_commit = 0;
818 if (!argc)
819 usage_with_options(builtin_merge_usage,
820 builtin_merge_options);
823 * This could be traditional "merge <msg> HEAD <commit>..." and
824 * the way we can tell it is to see if the second token is HEAD,
825 * but some people might have misused the interface and used a
826 * committish that is the same as HEAD there instead.
827 * Traditional format never would have "-m" so it is an
828 * additional safety measure to check for it.
830 strbuf_init(&buf, 0);
832 if (!have_message && is_old_style_invocation(argc, argv)) {
833 strbuf_addstr(&merge_msg, argv[0]);
834 head_arg = argv[1];
835 argv += 2;
836 argc -= 2;
837 } else if (head_invalid) {
838 struct object *remote_head;
840 * If the merged head is a valid one there is no reason
841 * to forbid "git merge" into a branch yet to be born.
842 * We do the same for "git pull".
844 if (argc != 1)
845 die("Can merge only exactly one commit into "
846 "empty head");
847 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
848 if (!remote_head)
849 die("%s - not something we can merge", argv[0]);
850 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
851 DIE_ON_ERR);
852 reset_hard(remote_head->sha1, 0);
853 return 0;
854 } else {
855 struct strbuf msg;
857 /* We are invoked directly as the first-class UI. */
858 head_arg = "HEAD";
861 * All the rest are the commits being merged;
862 * prepare the standard merge summary message to
863 * be appended to the given message. If remote
864 * is invalid we will die later in the common
865 * codepath so we discard the error in this
866 * loop.
868 strbuf_init(&msg, 0);
869 for (i = 0; i < argc; i++)
870 merge_name(argv[i], &msg);
871 fmt_merge_msg(option_log, &msg, &merge_msg);
872 if (merge_msg.len)
873 strbuf_setlen(&merge_msg, merge_msg.len-1);
876 if (head_invalid || !argc)
877 usage_with_options(builtin_merge_usage,
878 builtin_merge_options);
880 strbuf_addstr(&buf, "merge");
881 for (i = 0; i < argc; i++)
882 strbuf_addf(&buf, " %s", argv[i]);
883 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
884 strbuf_reset(&buf);
886 for (i = 0; i < argc; i++) {
887 struct object *o;
889 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
890 if (!o)
891 die("%s - not something we can merge", argv[i]);
892 remotes = &commit_list_insert(lookup_commit(o->sha1),
893 remotes)->next;
895 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
896 setenv(buf.buf, argv[i], 1);
897 strbuf_reset(&buf);
900 if (!use_strategies) {
901 if (!remoteheads->next)
902 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
903 else
904 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
907 for (i = 0; i < use_strategies_nr; i++) {
908 if (use_strategies[i]->attr & NO_FAST_FORWARD)
909 allow_fast_forward = 0;
910 if (use_strategies[i]->attr & NO_TRIVIAL)
911 allow_trivial = 0;
914 if (!remoteheads->next)
915 common = get_merge_bases(lookup_commit(head),
916 remoteheads->item, 1);
917 else {
918 struct commit_list *list = remoteheads;
919 commit_list_insert(lookup_commit(head), &list);
920 common = get_octopus_merge_bases(list);
921 free(list);
924 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
925 DIE_ON_ERR);
927 if (!common)
928 ; /* No common ancestors found. We need a real merge. */
929 else if (!remoteheads->next && !common->next &&
930 common->item == remoteheads->item) {
932 * If head can reach all the merge then we are up to date.
933 * but first the most common case of merging one remote.
935 finish_up_to_date("Already up-to-date.");
936 return 0;
937 } else if (allow_fast_forward && !remoteheads->next &&
938 !common->next &&
939 !hashcmp(common->item->object.sha1, head)) {
940 /* Again the most common case of merging one remote. */
941 struct strbuf msg;
942 struct object *o;
943 char hex[41];
945 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
947 printf("Updating %s..%s\n",
948 hex,
949 find_unique_abbrev(remoteheads->item->object.sha1,
950 DEFAULT_ABBREV));
951 refresh_cache(REFRESH_QUIET);
952 strbuf_init(&msg, 0);
953 strbuf_addstr(&msg, "Fast forward");
954 if (have_message)
955 strbuf_addstr(&msg,
956 " (no commit created; -m option ignored)");
957 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
958 0, NULL, OBJ_COMMIT);
959 if (!o)
960 return 1;
962 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
963 return 1;
965 finish(o->sha1, msg.buf);
966 drop_save();
967 return 0;
968 } else if (!remoteheads->next && common->next)
971 * We are not doing octopus and not fast forward. Need
972 * a real merge.
974 else if (!remoteheads->next && !common->next && option_commit) {
976 * We are not doing octopus, not fast forward, and have
977 * only one common.
979 refresh_cache(REFRESH_QUIET);
980 if (allow_trivial) {
981 /* See if it is really trivial. */
982 git_committer_info(IDENT_ERROR_ON_NO_NAME);
983 printf("Trying really trivial in-index merge...\n");
984 if (!read_tree_trivial(common->item->object.sha1,
985 head, remoteheads->item->object.sha1))
986 return merge_trivial();
987 printf("Nope.\n");
989 } else {
991 * An octopus. If we can reach all the remote we are up
992 * to date.
994 int up_to_date = 1;
995 struct commit_list *j;
997 for (j = remoteheads; j; j = j->next) {
998 struct commit_list *common_one;
1001 * Here we *have* to calculate the individual
1002 * merge_bases again, otherwise "git merge HEAD^
1003 * HEAD^^" would be missed.
1005 common_one = get_merge_bases(lookup_commit(head),
1006 j->item, 1);
1007 if (hashcmp(common_one->item->object.sha1,
1008 j->item->object.sha1)) {
1009 up_to_date = 0;
1010 break;
1013 if (up_to_date) {
1014 finish_up_to_date("Already up-to-date. Yeeah!");
1015 return 0;
1019 /* We are going to make a new commit. */
1020 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1023 * At this point, we need a real merge. No matter what strategy
1024 * we use, it would operate on the index, possibly affecting the
1025 * working tree, and when resolved cleanly, have the desired
1026 * tree in the index -- this means that the index must be in
1027 * sync with the head commit. The strategies are responsible
1028 * to ensure this.
1030 if (use_strategies_nr != 1) {
1032 * Stash away the local changes so that we can try more
1033 * than one.
1035 save_state();
1036 } else {
1037 memcpy(stash, null_sha1, 20);
1040 for (i = 0; i < use_strategies_nr; i++) {
1041 int ret;
1042 if (i) {
1043 printf("Rewinding the tree to pristine...\n");
1044 restore_state();
1046 if (use_strategies_nr != 1)
1047 printf("Trying merge strategy %s...\n",
1048 use_strategies[i]->name);
1050 * Remember which strategy left the state in the working
1051 * tree.
1053 wt_strategy = use_strategies[i]->name;
1055 ret = try_merge_strategy(use_strategies[i]->name,
1056 common, head_arg);
1057 if (!option_commit && !ret) {
1058 merge_was_ok = 1;
1060 * This is necessary here just to avoid writing
1061 * the tree, but later we will *not* exit with
1062 * status code 1 because merge_was_ok is set.
1064 ret = 1;
1067 if (ret) {
1069 * The backend exits with 1 when conflicts are
1070 * left to be resolved, with 2 when it does not
1071 * handle the given merge at all.
1073 if (ret == 1) {
1074 int cnt = evaluate_result();
1076 if (best_cnt <= 0 || cnt <= best_cnt) {
1077 best_strategy = use_strategies[i]->name;
1078 best_cnt = cnt;
1081 if (merge_was_ok)
1082 break;
1083 else
1084 continue;
1087 /* Automerge succeeded. */
1088 write_tree_trivial(result_tree);
1089 automerge_was_ok = 1;
1090 break;
1094 * If we have a resulting tree, that means the strategy module
1095 * auto resolved the merge cleanly.
1097 if (automerge_was_ok)
1098 return finish_automerge(common, result_tree, wt_strategy);
1101 * Pick the result from the best strategy and have the user fix
1102 * it up.
1104 if (!best_strategy) {
1105 restore_state();
1106 if (use_strategies_nr > 1)
1107 fprintf(stderr,
1108 "No merge strategy handled the merge.\n");
1109 else
1110 fprintf(stderr, "Merge with strategy %s failed.\n",
1111 use_strategies[0]->name);
1112 return 2;
1113 } else if (best_strategy == wt_strategy)
1114 ; /* We already have its result in the working tree. */
1115 else {
1116 printf("Rewinding the tree to pristine...\n");
1117 restore_state();
1118 printf("Using the %s to prepare resolving by hand.\n",
1119 best_strategy);
1120 try_merge_strategy(best_strategy, common, head_arg);
1123 if (squash)
1124 finish(NULL, NULL);
1125 else {
1126 int fd;
1127 struct commit_list *j;
1129 for (j = remoteheads; j; j = j->next)
1130 strbuf_addf(&buf, "%s\n",
1131 sha1_to_hex(j->item->object.sha1));
1132 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1133 if (fd < 0)
1134 die("Could open %s for writing",
1135 git_path("MERGE_HEAD"));
1136 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1137 die("Could not write to %s", git_path("MERGE_HEAD"));
1138 close(fd);
1139 strbuf_addch(&merge_msg, '\n');
1140 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1141 if (fd < 0)
1142 die("Could open %s for writing", git_path("MERGE_MSG"));
1143 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1144 merge_msg.len)
1145 die("Could not write to %s", git_path("MERGE_MSG"));
1146 close(fd);
1149 if (merge_was_ok) {
1150 fprintf(stderr, "Automatic merge went well; "
1151 "stopped before committing as requested\n");
1152 return 0;
1153 } else
1154 return suggest_conflicts();