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[alt-git.git] / builtin-merge.c
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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"
25 #include "help.h"
26 #include "merge-recursive.h"
28 #define DEFAULT_TWOHEAD (1<<0)
29 #define DEFAULT_OCTOPUS (1<<1)
30 #define NO_FAST_FORWARD (1<<2)
31 #define NO_TRIVIAL (1<<3)
33 struct strategy {
34 const char *name;
35 unsigned attr;
38 static const char * const builtin_merge_usage[] = {
39 "git merge [options] <remote>...",
40 "git merge [options] <msg> HEAD <remote>",
41 NULL
44 static int show_diffstat = 1, option_log, squash;
45 static int option_commit = 1, allow_fast_forward = 1;
46 static int allow_trivial = 1, have_message;
47 static struct strbuf merge_msg;
48 static struct commit_list *remoteheads;
49 static unsigned char head[20], stash[20];
50 static struct strategy **use_strategies;
51 static size_t use_strategies_nr, use_strategies_alloc;
52 static const char *branch;
53 static int verbosity;
55 static struct strategy all_strategy[] = {
56 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
57 { "octopus", DEFAULT_OCTOPUS },
58 { "resolve", 0 },
59 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
60 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
63 static const char *pull_twohead, *pull_octopus;
65 static int option_parse_message(const struct option *opt,
66 const char *arg, int unset)
68 struct strbuf *buf = opt->value;
70 if (unset)
71 strbuf_setlen(buf, 0);
72 else if (arg) {
73 strbuf_addf(buf, "%s\n\n", arg);
74 have_message = 1;
75 } else
76 return error("switch `m' requires a value");
77 return 0;
80 static struct strategy *get_strategy(const char *name)
82 int i;
83 struct strategy *ret;
84 static struct cmdnames main_cmds, other_cmds;
85 static int loaded;
87 if (!name)
88 return NULL;
90 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
91 if (!strcmp(name, all_strategy[i].name))
92 return &all_strategy[i];
94 if (!loaded) {
95 struct cmdnames not_strategies;
96 loaded = 1;
98 memset(&not_strategies, 0, sizeof(struct cmdnames));
99 load_command_list("git-merge-", &main_cmds, &other_cmds);
100 for (i = 0; i < main_cmds.cnt; i++) {
101 int j, found = 0;
102 struct cmdname *ent = main_cmds.names[i];
103 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
104 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
105 && !all_strategy[j].name[ent->len])
106 found = 1;
107 if (!found)
108 add_cmdname(&not_strategies, ent->name, ent->len);
109 exclude_cmds(&main_cmds, &not_strategies);
112 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
113 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
114 fprintf(stderr, "Available strategies are:");
115 for (i = 0; i < main_cmds.cnt; i++)
116 fprintf(stderr, " %s", main_cmds.names[i]->name);
117 fprintf(stderr, ".\n");
118 if (other_cmds.cnt) {
119 fprintf(stderr, "Available custom strategies are:");
120 for (i = 0; i < other_cmds.cnt; i++)
121 fprintf(stderr, " %s", other_cmds.names[i]->name);
122 fprintf(stderr, ".\n");
124 exit(1);
127 ret = xcalloc(1, sizeof(struct strategy));
128 ret->name = xstrdup(name);
129 return ret;
132 static void append_strategy(struct strategy *s)
134 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
135 use_strategies[use_strategies_nr++] = s;
138 static int option_parse_strategy(const struct option *opt,
139 const char *name, int unset)
141 if (unset)
142 return 0;
144 append_strategy(get_strategy(name));
145 return 0;
148 static int option_parse_n(const struct option *opt,
149 const char *arg, int unset)
151 show_diffstat = unset;
152 return 0;
155 static struct option builtin_merge_options[] = {
156 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
157 "do not show a diffstat at the end of the merge",
158 PARSE_OPT_NOARG, option_parse_n },
159 OPT_BOOLEAN(0, "stat", &show_diffstat,
160 "show a diffstat at the end of the merge"),
161 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
162 OPT_BOOLEAN(0, "log", &option_log,
163 "add list of one-line log to merge commit message"),
164 OPT_BOOLEAN(0, "squash", &squash,
165 "create a single commit instead of doing a merge"),
166 OPT_BOOLEAN(0, "commit", &option_commit,
167 "perform a commit if the merge succeeds (default)"),
168 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
169 "allow fast forward (default)"),
170 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
171 "merge strategy to use", option_parse_strategy),
172 OPT_CALLBACK('m', "message", &merge_msg, "message",
173 "message to be used for the merge commit (if any)",
174 option_parse_message),
175 OPT__VERBOSITY(&verbosity),
176 OPT_END()
179 /* Cleans up metadata that is uninteresting after a succeeded merge. */
180 static void drop_save(void)
182 unlink(git_path("MERGE_HEAD"));
183 unlink(git_path("MERGE_MSG"));
184 unlink(git_path("MERGE_MODE"));
187 static void save_state(void)
189 int len;
190 struct child_process cp;
191 struct strbuf buffer = STRBUF_INIT;
192 const char *argv[] = {"stash", "create", NULL};
194 memset(&cp, 0, sizeof(cp));
195 cp.argv = argv;
196 cp.out = -1;
197 cp.git_cmd = 1;
199 if (start_command(&cp))
200 die("could not run stash.");
201 len = strbuf_read(&buffer, cp.out, 1024);
202 close(cp.out);
204 if (finish_command(&cp) || len < 0)
205 die("stash failed");
206 else if (!len)
207 return;
208 strbuf_setlen(&buffer, buffer.len-1);
209 if (get_sha1(buffer.buf, stash))
210 die("not a valid object: %s", buffer.buf);
213 static void reset_hard(unsigned const char *sha1, int verbose)
215 int i = 0;
216 const char *args[6];
218 args[i++] = "read-tree";
219 if (verbose)
220 args[i++] = "-v";
221 args[i++] = "--reset";
222 args[i++] = "-u";
223 args[i++] = sha1_to_hex(sha1);
224 args[i] = NULL;
226 if (run_command_v_opt(args, RUN_GIT_CMD))
227 die("read-tree failed");
230 static void restore_state(void)
232 struct strbuf sb = STRBUF_INIT;
233 const char *args[] = { "stash", "apply", NULL, NULL };
235 if (is_null_sha1(stash))
236 return;
238 reset_hard(head, 1);
240 args[2] = sha1_to_hex(stash);
243 * It is OK to ignore error here, for example when there was
244 * nothing to restore.
246 run_command_v_opt(args, RUN_GIT_CMD);
248 strbuf_release(&sb);
249 refresh_cache(REFRESH_QUIET);
252 /* This is called when no merge was necessary. */
253 static void finish_up_to_date(const char *msg)
255 if (verbosity >= 0)
256 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
257 drop_save();
260 static void squash_message(void)
262 struct rev_info rev;
263 struct commit *commit;
264 struct strbuf out = STRBUF_INIT;
265 struct commit_list *j;
266 int fd;
268 printf("Squash commit -- not updating HEAD\n");
269 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
270 if (fd < 0)
271 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
273 init_revisions(&rev, NULL);
274 rev.ignore_merges = 1;
275 rev.commit_format = CMIT_FMT_MEDIUM;
277 commit = lookup_commit(head);
278 commit->object.flags |= UNINTERESTING;
279 add_pending_object(&rev, &commit->object, NULL);
281 for (j = remoteheads; j; j = j->next)
282 add_pending_object(&rev, &j->item->object, NULL);
284 setup_revisions(0, NULL, &rev, NULL);
285 if (prepare_revision_walk(&rev))
286 die("revision walk setup failed");
288 strbuf_addstr(&out, "Squashed commit of the following:\n");
289 while ((commit = get_revision(&rev)) != NULL) {
290 strbuf_addch(&out, '\n');
291 strbuf_addf(&out, "commit %s\n",
292 sha1_to_hex(commit->object.sha1));
293 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
294 NULL, NULL, rev.date_mode, 0);
296 if (write(fd, out.buf, out.len) < 0)
297 die_errno("Writing SQUASH_MSG");
298 if (close(fd))
299 die_errno("Finishing SQUASH_MSG");
300 strbuf_release(&out);
303 static void finish(const unsigned char *new_head, const char *msg)
305 struct strbuf reflog_message = STRBUF_INIT;
307 if (!msg)
308 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
309 else {
310 if (verbosity >= 0)
311 printf("%s\n", msg);
312 strbuf_addf(&reflog_message, "%s: %s",
313 getenv("GIT_REFLOG_ACTION"), msg);
315 if (squash) {
316 squash_message();
317 } else {
318 if (verbosity >= 0 && !merge_msg.len)
319 printf("No merge message -- not updating HEAD\n");
320 else {
321 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
322 update_ref(reflog_message.buf, "HEAD",
323 new_head, head, 0,
324 DIE_ON_ERR);
326 * We ignore errors in 'gc --auto', since the
327 * user should see them.
329 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
332 if (new_head && show_diffstat) {
333 struct diff_options opts;
334 diff_setup(&opts);
335 opts.output_format |=
336 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
337 opts.detect_rename = DIFF_DETECT_RENAME;
338 if (diff_use_color_default > 0)
339 DIFF_OPT_SET(&opts, COLOR_DIFF);
340 if (diff_setup_done(&opts) < 0)
341 die("diff_setup_done failed");
342 diff_tree_sha1(head, new_head, "", &opts);
343 diffcore_std(&opts);
344 diff_flush(&opts);
347 /* Run a post-merge hook */
348 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
350 strbuf_release(&reflog_message);
353 /* Get the name for the merge commit's message. */
354 static void merge_name(const char *remote, struct strbuf *msg)
356 struct object *remote_head;
357 unsigned char branch_head[20], buf_sha[20];
358 struct strbuf buf = STRBUF_INIT;
359 struct strbuf bname = STRBUF_INIT;
360 const char *ptr;
361 int len, early;
363 strbuf_branchname(&bname, remote);
364 remote = bname.buf;
366 memset(branch_head, 0, sizeof(branch_head));
367 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
368 if (!remote_head)
369 die("'%s' does not point to a commit", remote);
371 strbuf_addstr(&buf, "refs/heads/");
372 strbuf_addstr(&buf, remote);
373 resolve_ref(buf.buf, branch_head, 0, NULL);
375 if (!hashcmp(remote_head->sha1, branch_head)) {
376 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
377 sha1_to_hex(branch_head), remote);
378 goto cleanup;
381 /* See if remote matches <name>^^^.. or <name>~<number> */
382 for (len = 0, ptr = remote + strlen(remote);
383 remote < ptr && ptr[-1] == '^';
384 ptr--)
385 len++;
386 if (len)
387 early = 1;
388 else {
389 early = 0;
390 ptr = strrchr(remote, '~');
391 if (ptr) {
392 int seen_nonzero = 0;
394 len++; /* count ~ */
395 while (*++ptr && isdigit(*ptr)) {
396 seen_nonzero |= (*ptr != '0');
397 len++;
399 if (*ptr)
400 len = 0; /* not ...~<number> */
401 else if (seen_nonzero)
402 early = 1;
403 else if (len == 1)
404 early = 1; /* "name~" is "name~1"! */
407 if (len) {
408 struct strbuf truname = STRBUF_INIT;
409 strbuf_addstr(&truname, "refs/heads/");
410 strbuf_addstr(&truname, remote);
411 strbuf_setlen(&truname, truname.len - len);
412 if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
413 strbuf_addf(msg,
414 "%s\t\tbranch '%s'%s of .\n",
415 sha1_to_hex(remote_head->sha1),
416 truname.buf + 11,
417 (early ? " (early part)" : ""));
418 strbuf_release(&truname);
419 goto cleanup;
423 if (!strcmp(remote, "FETCH_HEAD") &&
424 !access(git_path("FETCH_HEAD"), R_OK)) {
425 FILE *fp;
426 struct strbuf line = STRBUF_INIT;
427 char *ptr;
429 fp = fopen(git_path("FETCH_HEAD"), "r");
430 if (!fp)
431 die_errno("could not open '%s' for reading",
432 git_path("FETCH_HEAD"));
433 strbuf_getline(&line, fp, '\n');
434 fclose(fp);
435 ptr = strstr(line.buf, "\tnot-for-merge\t");
436 if (ptr)
437 strbuf_remove(&line, ptr-line.buf+1, 13);
438 strbuf_addbuf(msg, &line);
439 strbuf_release(&line);
440 goto cleanup;
442 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
443 sha1_to_hex(remote_head->sha1), remote);
444 cleanup:
445 strbuf_release(&buf);
446 strbuf_release(&bname);
449 static int git_merge_config(const char *k, const char *v, void *cb)
451 if (branch && !prefixcmp(k, "branch.") &&
452 !prefixcmp(k + 7, branch) &&
453 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
454 const char **argv;
455 int argc;
456 char *buf;
458 buf = xstrdup(v);
459 argc = split_cmdline(buf, &argv);
460 if (argc < 0)
461 die("Bad branch.%s.mergeoptions string", branch);
462 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
463 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
464 argc++;
465 parse_options(argc, argv, NULL, builtin_merge_options,
466 builtin_merge_usage, 0);
467 free(buf);
470 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
471 show_diffstat = git_config_bool(k, v);
472 else if (!strcmp(k, "pull.twohead"))
473 return git_config_string(&pull_twohead, k, v);
474 else if (!strcmp(k, "pull.octopus"))
475 return git_config_string(&pull_octopus, k, v);
476 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
477 option_log = git_config_bool(k, v);
478 return git_diff_ui_config(k, v, cb);
481 static int read_tree_trivial(unsigned char *common, unsigned char *head,
482 unsigned char *one)
484 int i, nr_trees = 0;
485 struct tree *trees[MAX_UNPACK_TREES];
486 struct tree_desc t[MAX_UNPACK_TREES];
487 struct unpack_trees_options opts;
489 memset(&opts, 0, sizeof(opts));
490 opts.head_idx = 2;
491 opts.src_index = &the_index;
492 opts.dst_index = &the_index;
493 opts.update = 1;
494 opts.verbose_update = 1;
495 opts.trivial_merges_only = 1;
496 opts.merge = 1;
497 trees[nr_trees] = parse_tree_indirect(common);
498 if (!trees[nr_trees++])
499 return -1;
500 trees[nr_trees] = parse_tree_indirect(head);
501 if (!trees[nr_trees++])
502 return -1;
503 trees[nr_trees] = parse_tree_indirect(one);
504 if (!trees[nr_trees++])
505 return -1;
506 opts.fn = threeway_merge;
507 cache_tree_free(&active_cache_tree);
508 for (i = 0; i < nr_trees; i++) {
509 parse_tree(trees[i]);
510 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
512 if (unpack_trees(nr_trees, t, &opts))
513 return -1;
514 return 0;
517 static void write_tree_trivial(unsigned char *sha1)
519 if (write_cache_as_tree(sha1, 0, NULL))
520 die("git write-tree failed to write a tree");
523 static int try_merge_strategy(const char *strategy, struct commit_list *common,
524 const char *head_arg)
526 const char **args;
527 int i = 0, ret;
528 struct commit_list *j;
529 struct strbuf buf = STRBUF_INIT;
530 int index_fd;
531 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
533 index_fd = hold_locked_index(lock, 1);
534 refresh_cache(REFRESH_QUIET);
535 if (active_cache_changed &&
536 (write_cache(index_fd, active_cache, active_nr) ||
537 commit_locked_index(lock)))
538 return error("Unable to write index.");
539 rollback_lock_file(lock);
541 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
542 int clean;
543 struct commit *result;
544 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
545 int index_fd;
546 struct commit_list *reversed = NULL;
547 struct merge_options o;
549 if (remoteheads->next) {
550 error("Not handling anything other than two heads merge.");
551 return 2;
554 init_merge_options(&o);
555 if (!strcmp(strategy, "subtree"))
556 o.subtree_merge = 1;
558 o.branch1 = head_arg;
559 o.branch2 = remoteheads->item->util;
561 for (j = common; j; j = j->next)
562 commit_list_insert(j->item, &reversed);
564 index_fd = hold_locked_index(lock, 1);
565 clean = merge_recursive(&o, lookup_commit(head),
566 remoteheads->item, reversed, &result);
567 if (active_cache_changed &&
568 (write_cache(index_fd, active_cache, active_nr) ||
569 commit_locked_index(lock)))
570 die ("unable to write %s", get_index_file());
571 rollback_lock_file(lock);
572 return clean ? 0 : 1;
573 } else {
574 args = xmalloc((4 + commit_list_count(common) +
575 commit_list_count(remoteheads)) * sizeof(char *));
576 strbuf_addf(&buf, "merge-%s", strategy);
577 args[i++] = buf.buf;
578 for (j = common; j; j = j->next)
579 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
580 args[i++] = "--";
581 args[i++] = head_arg;
582 for (j = remoteheads; j; j = j->next)
583 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
584 args[i] = NULL;
585 ret = run_command_v_opt(args, RUN_GIT_CMD);
586 strbuf_release(&buf);
587 i = 1;
588 for (j = common; j; j = j->next)
589 free((void *)args[i++]);
590 i += 2;
591 for (j = remoteheads; j; j = j->next)
592 free((void *)args[i++]);
593 free(args);
594 discard_cache();
595 if (read_cache() < 0)
596 die("failed to read the cache");
597 return -ret;
601 static void count_diff_files(struct diff_queue_struct *q,
602 struct diff_options *opt, void *data)
604 int *count = data;
606 (*count) += q->nr;
609 static int count_unmerged_entries(void)
611 const struct index_state *state = &the_index;
612 int i, ret = 0;
614 for (i = 0; i < state->cache_nr; i++)
615 if (ce_stage(state->cache[i]))
616 ret++;
618 return ret;
621 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
623 struct tree *trees[MAX_UNPACK_TREES];
624 struct unpack_trees_options opts;
625 struct tree_desc t[MAX_UNPACK_TREES];
626 int i, fd, nr_trees = 0;
627 struct dir_struct dir;
628 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
630 refresh_cache(REFRESH_QUIET);
632 fd = hold_locked_index(lock_file, 1);
634 memset(&trees, 0, sizeof(trees));
635 memset(&opts, 0, sizeof(opts));
636 memset(&t, 0, sizeof(t));
637 memset(&dir, 0, sizeof(dir));
638 dir.flags |= DIR_SHOW_IGNORED;
639 dir.exclude_per_dir = ".gitignore";
640 opts.dir = &dir;
642 opts.head_idx = 1;
643 opts.src_index = &the_index;
644 opts.dst_index = &the_index;
645 opts.update = 1;
646 opts.verbose_update = 1;
647 opts.merge = 1;
648 opts.fn = twoway_merge;
650 trees[nr_trees] = parse_tree_indirect(head);
651 if (!trees[nr_trees++])
652 return -1;
653 trees[nr_trees] = parse_tree_indirect(remote);
654 if (!trees[nr_trees++])
655 return -1;
656 for (i = 0; i < nr_trees; i++) {
657 parse_tree(trees[i]);
658 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
660 if (unpack_trees(nr_trees, t, &opts))
661 return -1;
662 if (write_cache(fd, active_cache, active_nr) ||
663 commit_locked_index(lock_file))
664 die("unable to write new index file");
665 return 0;
668 static void split_merge_strategies(const char *string, struct strategy **list,
669 int *nr, int *alloc)
671 char *p, *q, *buf;
673 if (!string)
674 return;
676 buf = xstrdup(string);
677 q = buf;
678 for (;;) {
679 p = strchr(q, ' ');
680 if (!p) {
681 ALLOC_GROW(*list, *nr + 1, *alloc);
682 (*list)[(*nr)++].name = xstrdup(q);
683 free(buf);
684 return;
685 } else {
686 *p = '\0';
687 ALLOC_GROW(*list, *nr + 1, *alloc);
688 (*list)[(*nr)++].name = xstrdup(q);
689 q = ++p;
694 static void add_strategies(const char *string, unsigned attr)
696 struct strategy *list = NULL;
697 int list_alloc = 0, list_nr = 0, i;
699 memset(&list, 0, sizeof(list));
700 split_merge_strategies(string, &list, &list_nr, &list_alloc);
701 if (list) {
702 for (i = 0; i < list_nr; i++)
703 append_strategy(get_strategy(list[i].name));
704 return;
706 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
707 if (all_strategy[i].attr & attr)
708 append_strategy(&all_strategy[i]);
712 static int merge_trivial(void)
714 unsigned char result_tree[20], result_commit[20];
715 struct commit_list *parent = xmalloc(sizeof(*parent));
717 write_tree_trivial(result_tree);
718 printf("Wonderful.\n");
719 parent->item = lookup_commit(head);
720 parent->next = xmalloc(sizeof(*parent->next));
721 parent->next->item = remoteheads->item;
722 parent->next->next = NULL;
723 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
724 finish(result_commit, "In-index merge");
725 drop_save();
726 return 0;
729 static int finish_automerge(struct commit_list *common,
730 unsigned char *result_tree,
731 const char *wt_strategy)
733 struct commit_list *parents = NULL, *j;
734 struct strbuf buf = STRBUF_INIT;
735 unsigned char result_commit[20];
737 free_commit_list(common);
738 if (allow_fast_forward) {
739 parents = remoteheads;
740 commit_list_insert(lookup_commit(head), &parents);
741 parents = reduce_heads(parents);
742 } else {
743 struct commit_list **pptr = &parents;
745 pptr = &commit_list_insert(lookup_commit(head),
746 pptr)->next;
747 for (j = remoteheads; j; j = j->next)
748 pptr = &commit_list_insert(j->item, pptr)->next;
750 free_commit_list(remoteheads);
751 strbuf_addch(&merge_msg, '\n');
752 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
753 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
754 finish(result_commit, buf.buf);
755 strbuf_release(&buf);
756 drop_save();
757 return 0;
760 static int suggest_conflicts(void)
762 FILE *fp;
763 int pos;
765 fp = fopen(git_path("MERGE_MSG"), "a");
766 if (!fp)
767 die_errno("Could not open '%s' for writing",
768 git_path("MERGE_MSG"));
769 fprintf(fp, "\nConflicts:\n");
770 for (pos = 0; pos < active_nr; pos++) {
771 struct cache_entry *ce = active_cache[pos];
773 if (ce_stage(ce)) {
774 fprintf(fp, "\t%s\n", ce->name);
775 while (pos + 1 < active_nr &&
776 !strcmp(ce->name,
777 active_cache[pos + 1]->name))
778 pos++;
781 fclose(fp);
782 rerere();
783 printf("Automatic merge failed; "
784 "fix conflicts and then commit the result.\n");
785 return 1;
788 static struct commit *is_old_style_invocation(int argc, const char **argv)
790 struct commit *second_token = NULL;
791 if (argc > 1) {
792 unsigned char second_sha1[20];
794 if (get_sha1(argv[1], second_sha1))
795 return NULL;
796 second_token = lookup_commit_reference_gently(second_sha1, 0);
797 if (!second_token)
798 die("'%s' is not a commit", argv[1]);
799 if (hashcmp(second_token->object.sha1, head))
800 return NULL;
802 return second_token;
805 static int evaluate_result(void)
807 int cnt = 0;
808 struct rev_info rev;
810 /* Check how many files differ. */
811 init_revisions(&rev, "");
812 setup_revisions(0, NULL, &rev, NULL);
813 rev.diffopt.output_format |=
814 DIFF_FORMAT_CALLBACK;
815 rev.diffopt.format_callback = count_diff_files;
816 rev.diffopt.format_callback_data = &cnt;
817 run_diff_files(&rev, 0);
820 * Check how many unmerged entries are
821 * there.
823 cnt += count_unmerged_entries();
825 return cnt;
828 int cmd_merge(int argc, const char **argv, const char *prefix)
830 unsigned char result_tree[20];
831 struct strbuf buf = STRBUF_INIT;
832 const char *head_arg;
833 int flag, head_invalid = 0, i;
834 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
835 struct commit_list *common = NULL;
836 const char *best_strategy = NULL, *wt_strategy = NULL;
837 struct commit_list **remotes = &remoteheads;
839 setup_work_tree();
840 if (file_exists(git_path("MERGE_HEAD")))
841 die("You have not concluded your merge. (MERGE_HEAD exists)");
842 if (read_cache_unmerged())
843 die("You are in the middle of a conflicted merge."
844 " (index unmerged)");
847 * Check if we are _not_ on a detached HEAD, i.e. if there is a
848 * current branch.
850 branch = resolve_ref("HEAD", head, 0, &flag);
851 if (branch && !prefixcmp(branch, "refs/heads/"))
852 branch += 11;
853 if (is_null_sha1(head))
854 head_invalid = 1;
856 git_config(git_merge_config, NULL);
858 /* for color.ui */
859 if (diff_use_color_default == -1)
860 diff_use_color_default = git_use_color_default;
862 argc = parse_options(argc, argv, prefix, builtin_merge_options,
863 builtin_merge_usage, 0);
864 if (verbosity < 0)
865 show_diffstat = 0;
867 if (squash) {
868 if (!allow_fast_forward)
869 die("You cannot combine --squash with --no-ff.");
870 option_commit = 0;
873 if (!argc)
874 usage_with_options(builtin_merge_usage,
875 builtin_merge_options);
878 * This could be traditional "merge <msg> HEAD <commit>..." and
879 * the way we can tell it is to see if the second token is HEAD,
880 * but some people might have misused the interface and used a
881 * committish that is the same as HEAD there instead.
882 * Traditional format never would have "-m" so it is an
883 * additional safety measure to check for it.
886 if (!have_message && is_old_style_invocation(argc, argv)) {
887 strbuf_addstr(&merge_msg, argv[0]);
888 head_arg = argv[1];
889 argv += 2;
890 argc -= 2;
891 } else if (head_invalid) {
892 struct object *remote_head;
894 * If the merged head is a valid one there is no reason
895 * to forbid "git merge" into a branch yet to be born.
896 * We do the same for "git pull".
898 if (argc != 1)
899 die("Can merge only exactly one commit into "
900 "empty head");
901 if (squash)
902 die("Squash commit into empty head not supported yet");
903 if (!allow_fast_forward)
904 die("Non-fast-forward commit does not make sense into "
905 "an empty head");
906 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
907 if (!remote_head)
908 die("%s - not something we can merge", argv[0]);
909 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
910 DIE_ON_ERR);
911 reset_hard(remote_head->sha1, 0);
912 return 0;
913 } else {
914 struct strbuf msg = STRBUF_INIT;
916 /* We are invoked directly as the first-class UI. */
917 head_arg = "HEAD";
920 * All the rest are the commits being merged;
921 * prepare the standard merge summary message to
922 * be appended to the given message. If remote
923 * is invalid we will die later in the common
924 * codepath so we discard the error in this
925 * loop.
927 for (i = 0; i < argc; i++)
928 merge_name(argv[i], &msg);
929 fmt_merge_msg(option_log, &msg, &merge_msg);
930 if (merge_msg.len)
931 strbuf_setlen(&merge_msg, merge_msg.len-1);
934 if (head_invalid || !argc)
935 usage_with_options(builtin_merge_usage,
936 builtin_merge_options);
938 strbuf_addstr(&buf, "merge");
939 for (i = 0; i < argc; i++)
940 strbuf_addf(&buf, " %s", argv[i]);
941 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
942 strbuf_reset(&buf);
944 for (i = 0; i < argc; i++) {
945 struct object *o;
946 struct commit *commit;
948 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
949 if (!o)
950 die("%s - not something we can merge", argv[i]);
951 commit = lookup_commit(o->sha1);
952 commit->util = (void *)argv[i];
953 remotes = &commit_list_insert(commit, remotes)->next;
955 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
956 setenv(buf.buf, argv[i], 1);
957 strbuf_reset(&buf);
960 if (!use_strategies) {
961 if (!remoteheads->next)
962 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
963 else
964 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
967 for (i = 0; i < use_strategies_nr; i++) {
968 if (use_strategies[i]->attr & NO_FAST_FORWARD)
969 allow_fast_forward = 0;
970 if (use_strategies[i]->attr & NO_TRIVIAL)
971 allow_trivial = 0;
974 if (!remoteheads->next)
975 common = get_merge_bases(lookup_commit(head),
976 remoteheads->item, 1);
977 else {
978 struct commit_list *list = remoteheads;
979 commit_list_insert(lookup_commit(head), &list);
980 common = get_octopus_merge_bases(list);
981 free(list);
984 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
985 DIE_ON_ERR);
987 if (!common)
988 ; /* No common ancestors found. We need a real merge. */
989 else if (!remoteheads->next && !common->next &&
990 common->item == remoteheads->item) {
992 * If head can reach all the merge then we are up to date.
993 * but first the most common case of merging one remote.
995 finish_up_to_date("Already up-to-date.");
996 return 0;
997 } else if (allow_fast_forward && !remoteheads->next &&
998 !common->next &&
999 !hashcmp(common->item->object.sha1, head)) {
1000 /* Again the most common case of merging one remote. */
1001 struct strbuf msg = STRBUF_INIT;
1002 struct object *o;
1003 char hex[41];
1005 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1007 if (verbosity >= 0)
1008 printf("Updating %s..%s\n",
1009 hex,
1010 find_unique_abbrev(remoteheads->item->object.sha1,
1011 DEFAULT_ABBREV));
1012 strbuf_addstr(&msg, "Fast forward");
1013 if (have_message)
1014 strbuf_addstr(&msg,
1015 " (no commit created; -m option ignored)");
1016 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1017 0, NULL, OBJ_COMMIT);
1018 if (!o)
1019 return 1;
1021 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1022 return 1;
1024 finish(o->sha1, msg.buf);
1025 drop_save();
1026 return 0;
1027 } else if (!remoteheads->next && common->next)
1030 * We are not doing octopus and not fast forward. Need
1031 * a real merge.
1033 else if (!remoteheads->next && !common->next && option_commit) {
1035 * We are not doing octopus, not fast forward, and have
1036 * only one common.
1038 refresh_cache(REFRESH_QUIET);
1039 if (allow_trivial) {
1040 /* See if it is really trivial. */
1041 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1042 printf("Trying really trivial in-index merge...\n");
1043 if (!read_tree_trivial(common->item->object.sha1,
1044 head, remoteheads->item->object.sha1))
1045 return merge_trivial();
1046 printf("Nope.\n");
1048 } else {
1050 * An octopus. If we can reach all the remote we are up
1051 * to date.
1053 int up_to_date = 1;
1054 struct commit_list *j;
1056 for (j = remoteheads; j; j = j->next) {
1057 struct commit_list *common_one;
1060 * Here we *have* to calculate the individual
1061 * merge_bases again, otherwise "git merge HEAD^
1062 * HEAD^^" would be missed.
1064 common_one = get_merge_bases(lookup_commit(head),
1065 j->item, 1);
1066 if (hashcmp(common_one->item->object.sha1,
1067 j->item->object.sha1)) {
1068 up_to_date = 0;
1069 break;
1072 if (up_to_date) {
1073 finish_up_to_date("Already up-to-date. Yeeah!");
1074 return 0;
1078 /* We are going to make a new commit. */
1079 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1082 * At this point, we need a real merge. No matter what strategy
1083 * we use, it would operate on the index, possibly affecting the
1084 * working tree, and when resolved cleanly, have the desired
1085 * tree in the index -- this means that the index must be in
1086 * sync with the head commit. The strategies are responsible
1087 * to ensure this.
1089 if (use_strategies_nr != 1) {
1091 * Stash away the local changes so that we can try more
1092 * than one.
1094 save_state();
1095 } else {
1096 memcpy(stash, null_sha1, 20);
1099 for (i = 0; i < use_strategies_nr; i++) {
1100 int ret;
1101 if (i) {
1102 printf("Rewinding the tree to pristine...\n");
1103 restore_state();
1105 if (use_strategies_nr != 1)
1106 printf("Trying merge strategy %s...\n",
1107 use_strategies[i]->name);
1109 * Remember which strategy left the state in the working
1110 * tree.
1112 wt_strategy = use_strategies[i]->name;
1114 ret = try_merge_strategy(use_strategies[i]->name,
1115 common, head_arg);
1116 if (!option_commit && !ret) {
1117 merge_was_ok = 1;
1119 * This is necessary here just to avoid writing
1120 * the tree, but later we will *not* exit with
1121 * status code 1 because merge_was_ok is set.
1123 ret = 1;
1126 if (ret) {
1128 * The backend exits with 1 when conflicts are
1129 * left to be resolved, with 2 when it does not
1130 * handle the given merge at all.
1132 if (ret == 1) {
1133 int cnt = evaluate_result();
1135 if (best_cnt <= 0 || cnt <= best_cnt) {
1136 best_strategy = use_strategies[i]->name;
1137 best_cnt = cnt;
1140 if (merge_was_ok)
1141 break;
1142 else
1143 continue;
1146 /* Automerge succeeded. */
1147 write_tree_trivial(result_tree);
1148 automerge_was_ok = 1;
1149 break;
1153 * If we have a resulting tree, that means the strategy module
1154 * auto resolved the merge cleanly.
1156 if (automerge_was_ok)
1157 return finish_automerge(common, result_tree, wt_strategy);
1160 * Pick the result from the best strategy and have the user fix
1161 * it up.
1163 if (!best_strategy) {
1164 restore_state();
1165 if (use_strategies_nr > 1)
1166 fprintf(stderr,
1167 "No merge strategy handled the merge.\n");
1168 else
1169 fprintf(stderr, "Merge with strategy %s failed.\n",
1170 use_strategies[0]->name);
1171 return 2;
1172 } else if (best_strategy == wt_strategy)
1173 ; /* We already have its result in the working tree. */
1174 else {
1175 printf("Rewinding the tree to pristine...\n");
1176 restore_state();
1177 printf("Using the %s to prepare resolving by hand.\n",
1178 best_strategy);
1179 try_merge_strategy(best_strategy, common, head_arg);
1182 if (squash)
1183 finish(NULL, NULL);
1184 else {
1185 int fd;
1186 struct commit_list *j;
1188 for (j = remoteheads; j; j = j->next)
1189 strbuf_addf(&buf, "%s\n",
1190 sha1_to_hex(j->item->object.sha1));
1191 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1192 if (fd < 0)
1193 die_errno("Could not open '%s' for writing",
1194 git_path("MERGE_HEAD"));
1195 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1196 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1197 close(fd);
1198 strbuf_addch(&merge_msg, '\n');
1199 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1200 if (fd < 0)
1201 die_errno("Could not open '%s' for writing",
1202 git_path("MERGE_MSG"));
1203 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1204 merge_msg.len)
1205 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1206 close(fd);
1207 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1208 if (fd < 0)
1209 die_errno("Could not open '%s' for writing",
1210 git_path("MERGE_MODE"));
1211 strbuf_reset(&buf);
1212 if (!allow_fast_forward)
1213 strbuf_addf(&buf, "no-ff");
1214 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1215 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1216 close(fd);
1219 if (merge_was_ok) {
1220 fprintf(stderr, "Automatic merge went well; "
1221 "stopped before committing as requested\n");
1222 return 0;
1223 } else
1224 return suggest_conflicts();