Merge commit 'refs/top-bases/girocco' into girocco
[git/repo.git] / builtin-merge.c
blob38266baf5fe9f54a0006baaae205b55f12ed15fc
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;
54 static struct strategy all_strategy[] = {
55 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
56 { "octopus", DEFAULT_OCTOPUS },
57 { "resolve", 0 },
58 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
59 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
62 static const char *pull_twohead, *pull_octopus;
64 static int option_parse_message(const struct option *opt,
65 const char *arg, int unset)
67 struct strbuf *buf = opt->value;
69 if (unset)
70 strbuf_setlen(buf, 0);
71 else if (arg) {
72 strbuf_addf(buf, "%s\n\n", arg);
73 have_message = 1;
74 } else
75 return error("switch `m' requires a value");
76 return 0;
79 static struct strategy *get_strategy(const char *name)
81 int i;
82 struct strategy *ret;
83 static struct cmdnames main_cmds, other_cmds;
84 static int loaded;
86 if (!name)
87 return NULL;
89 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
90 if (!strcmp(name, all_strategy[i].name))
91 return &all_strategy[i];
93 if (!loaded) {
94 struct cmdnames not_strategies;
95 loaded = 1;
97 memset(&not_strategies, 0, sizeof(struct cmdnames));
98 load_command_list("git-merge-", &main_cmds, &other_cmds);
99 for (i = 0; i < main_cmds.cnt; i++) {
100 int j, found = 0;
101 struct cmdname *ent = main_cmds.names[i];
102 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
103 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
104 && !all_strategy[j].name[ent->len])
105 found = 1;
106 if (!found)
107 add_cmdname(&not_strategies, ent->name, ent->len);
108 exclude_cmds(&main_cmds, &not_strategies);
111 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
112 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
113 fprintf(stderr, "Available strategies are:");
114 for (i = 0; i < main_cmds.cnt; i++)
115 fprintf(stderr, " %s", main_cmds.names[i]->name);
116 fprintf(stderr, ".\n");
117 if (other_cmds.cnt) {
118 fprintf(stderr, "Available custom strategies are:");
119 for (i = 0; i < other_cmds.cnt; i++)
120 fprintf(stderr, " %s", other_cmds.names[i]->name);
121 fprintf(stderr, ".\n");
123 exit(1);
126 ret = xcalloc(1, sizeof(struct strategy));
127 ret->name = xstrdup(name);
128 return ret;
131 static void append_strategy(struct strategy *s)
133 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
134 use_strategies[use_strategies_nr++] = s;
137 static int option_parse_strategy(const struct option *opt,
138 const char *name, int unset)
140 if (unset)
141 return 0;
143 append_strategy(get_strategy(name));
144 return 0;
147 static int option_parse_n(const struct option *opt,
148 const char *arg, int unset)
150 show_diffstat = unset;
151 return 0;
154 static struct option builtin_merge_options[] = {
155 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
156 "do not show a diffstat at the end of the merge",
157 PARSE_OPT_NOARG, option_parse_n },
158 OPT_BOOLEAN(0, "stat", &show_diffstat,
159 "show a diffstat at the end of the merge"),
160 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
161 OPT_BOOLEAN(0, "log", &option_log,
162 "add list of one-line log to merge commit message"),
163 OPT_BOOLEAN(0, "squash", &squash,
164 "create a single commit instead of doing a merge"),
165 OPT_BOOLEAN(0, "commit", &option_commit,
166 "perform a commit if the merge succeeds (default)"),
167 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
168 "allow fast forward (default)"),
169 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
170 "merge strategy to use", option_parse_strategy),
171 OPT_CALLBACK('m', "message", &merge_msg, "message",
172 "message to be used for the merge commit (if any)",
173 option_parse_message),
174 OPT_END()
177 /* Cleans up metadata that is uninteresting after a succeeded merge. */
178 static void drop_save(void)
180 unlink(git_path("MERGE_HEAD"));
181 unlink(git_path("MERGE_MSG"));
184 static void save_state(void)
186 int len;
187 struct child_process cp;
188 struct strbuf buffer = STRBUF_INIT;
189 const char *argv[] = {"stash", "create", NULL};
191 memset(&cp, 0, sizeof(cp));
192 cp.argv = argv;
193 cp.out = -1;
194 cp.git_cmd = 1;
196 if (start_command(&cp))
197 die("could not run stash.");
198 len = strbuf_read(&buffer, cp.out, 1024);
199 close(cp.out);
201 if (finish_command(&cp) || len < 0)
202 die("stash failed");
203 else if (!len)
204 return;
205 strbuf_setlen(&buffer, buffer.len-1);
206 if (get_sha1(buffer.buf, stash))
207 die("not a valid object: %s", buffer.buf);
210 static void reset_hard(unsigned const char *sha1, int verbose)
212 int i = 0;
213 const char *args[6];
215 args[i++] = "read-tree";
216 if (verbose)
217 args[i++] = "-v";
218 args[i++] = "--reset";
219 args[i++] = "-u";
220 args[i++] = sha1_to_hex(sha1);
221 args[i] = NULL;
223 if (run_command_v_opt(args, RUN_GIT_CMD))
224 die("read-tree failed");
227 static void restore_state(void)
229 struct strbuf sb;
230 const char *args[] = { "stash", "apply", NULL, NULL };
232 if (is_null_sha1(stash))
233 return;
235 reset_hard(head, 1);
237 strbuf_init(&sb, 0);
238 args[2] = sha1_to_hex(stash);
241 * It is OK to ignore error here, for example when there was
242 * nothing to restore.
244 run_command_v_opt(args, RUN_GIT_CMD);
246 strbuf_release(&sb);
247 refresh_cache(REFRESH_QUIET);
250 /* This is called when no merge was necessary. */
251 static void finish_up_to_date(const char *msg)
253 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
254 drop_save();
257 static void squash_message(void)
259 struct rev_info rev;
260 struct commit *commit;
261 struct strbuf out;
262 struct commit_list *j;
263 int fd;
265 printf("Squash commit -- not updating HEAD\n");
266 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
267 if (fd < 0)
268 die("Could not write to %s", git_path("SQUASH_MSG"));
270 init_revisions(&rev, NULL);
271 rev.ignore_merges = 1;
272 rev.commit_format = CMIT_FMT_MEDIUM;
274 commit = lookup_commit(head);
275 commit->object.flags |= UNINTERESTING;
276 add_pending_object(&rev, &commit->object, NULL);
278 for (j = remoteheads; j; j = j->next)
279 add_pending_object(&rev, &j->item->object, NULL);
281 setup_revisions(0, NULL, &rev, NULL);
282 if (prepare_revision_walk(&rev))
283 die("revision walk setup failed");
285 strbuf_init(&out, 0);
286 strbuf_addstr(&out, "Squashed commit of the following:\n");
287 while ((commit = get_revision(&rev)) != NULL) {
288 strbuf_addch(&out, '\n');
289 strbuf_addf(&out, "commit %s\n",
290 sha1_to_hex(commit->object.sha1));
291 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
292 NULL, NULL, rev.date_mode, 0);
294 write(fd, out.buf, out.len);
295 close(fd);
296 strbuf_release(&out);
299 static int run_hook(const char *name)
301 struct child_process hook;
302 const char *argv[3], *env[2];
303 char index[PATH_MAX];
305 argv[0] = git_path("hooks/%s", name);
306 if (access(argv[0], X_OK) < 0)
307 return 0;
309 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
310 env[0] = index;
311 env[1] = NULL;
313 if (squash)
314 argv[1] = "1";
315 else
316 argv[1] = "0";
317 argv[2] = NULL;
319 memset(&hook, 0, sizeof(hook));
320 hook.argv = argv;
321 hook.no_stdin = 1;
322 hook.stdout_to_stderr = 1;
323 hook.env = env;
325 return run_command(&hook);
328 static void finish(const unsigned char *new_head, const char *msg)
330 struct strbuf reflog_message;
332 strbuf_init(&reflog_message, 0);
333 if (!msg)
334 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
335 else {
336 printf("%s\n", msg);
337 strbuf_addf(&reflog_message, "%s: %s",
338 getenv("GIT_REFLOG_ACTION"), msg);
340 if (squash) {
341 squash_message();
342 } else {
343 if (!merge_msg.len)
344 printf("No merge message -- not updating HEAD\n");
345 else {
346 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
347 update_ref(reflog_message.buf, "HEAD",
348 new_head, head, 0,
349 DIE_ON_ERR);
351 * We ignore errors in 'gc --auto', since the
352 * user should see them.
354 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
357 if (new_head && show_diffstat) {
358 struct diff_options opts;
359 diff_setup(&opts);
360 opts.output_format |=
361 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
362 opts.detect_rename = DIFF_DETECT_RENAME;
363 if (diff_use_color_default > 0)
364 DIFF_OPT_SET(&opts, COLOR_DIFF);
365 if (diff_setup_done(&opts) < 0)
366 die("diff_setup_done failed");
367 diff_tree_sha1(head, new_head, "", &opts);
368 diffcore_std(&opts);
369 diff_flush(&opts);
372 /* Run a post-merge hook */
373 run_hook("post-merge");
375 strbuf_release(&reflog_message);
378 /* Get the name for the merge commit's message. */
379 static void merge_name(const char *remote, struct strbuf *msg)
381 struct object *remote_head;
382 unsigned char branch_head[20], buf_sha[20];
383 struct strbuf buf;
384 const char *ptr;
385 int len, early;
387 memset(branch_head, 0, sizeof(branch_head));
388 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
389 if (!remote_head)
390 die("'%s' does not point to a commit", remote);
392 strbuf_init(&buf, 0);
393 strbuf_addstr(&buf, "refs/heads/");
394 strbuf_addstr(&buf, remote);
395 resolve_ref(buf.buf, branch_head, 0, 0);
397 if (!hashcmp(remote_head->sha1, branch_head)) {
398 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
399 sha1_to_hex(branch_head), remote);
400 return;
403 /* See if remote matches <name>^^^.. or <name>~<number> */
404 for (len = 0, ptr = remote + strlen(remote);
405 remote < ptr && ptr[-1] == '^';
406 ptr--)
407 len++;
408 if (len)
409 early = 1;
410 else {
411 early = 0;
412 ptr = strrchr(remote, '~');
413 if (ptr) {
414 int seen_nonzero = 0;
416 len++; /* count ~ */
417 while (*++ptr && isdigit(*ptr)) {
418 seen_nonzero |= (*ptr != '0');
419 len++;
421 if (*ptr)
422 len = 0; /* not ...~<number> */
423 else if (seen_nonzero)
424 early = 1;
425 else if (len == 1)
426 early = 1; /* "name~" is "name~1"! */
429 if (len) {
430 struct strbuf truname = STRBUF_INIT;
431 strbuf_addstr(&truname, "refs/heads/");
432 strbuf_addstr(&truname, remote);
433 strbuf_setlen(&truname, truname.len - len);
434 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
435 strbuf_addf(msg,
436 "%s\t\tbranch '%s'%s of .\n",
437 sha1_to_hex(remote_head->sha1),
438 truname.buf + 11,
439 (early ? " (early part)" : ""));
440 return;
444 if (!strcmp(remote, "FETCH_HEAD") &&
445 !access(git_path("FETCH_HEAD"), R_OK)) {
446 FILE *fp;
447 struct strbuf line;
448 char *ptr;
450 strbuf_init(&line, 0);
451 fp = fopen(git_path("FETCH_HEAD"), "r");
452 if (!fp)
453 die("could not open %s for reading: %s",
454 git_path("FETCH_HEAD"), strerror(errno));
455 strbuf_getline(&line, fp, '\n');
456 fclose(fp);
457 ptr = strstr(line.buf, "\tnot-for-merge\t");
458 if (ptr)
459 strbuf_remove(&line, ptr-line.buf+1, 13);
460 strbuf_addbuf(msg, &line);
461 strbuf_release(&line);
462 return;
464 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
465 sha1_to_hex(remote_head->sha1), remote);
468 static int git_merge_config(const char *k, const char *v, void *cb)
470 if (branch && !prefixcmp(k, "branch.") &&
471 !prefixcmp(k + 7, branch) &&
472 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
473 const char **argv;
474 int argc;
475 char *buf;
477 buf = xstrdup(v);
478 argc = split_cmdline(buf, &argv);
479 if (argc < 0)
480 die("Bad branch.%s.mergeoptions string", branch);
481 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
482 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
483 argc++;
484 parse_options(argc, argv, builtin_merge_options,
485 builtin_merge_usage, 0);
486 free(buf);
489 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
490 show_diffstat = git_config_bool(k, v);
491 else if (!strcmp(k, "pull.twohead"))
492 return git_config_string(&pull_twohead, k, v);
493 else if (!strcmp(k, "pull.octopus"))
494 return git_config_string(&pull_octopus, k, v);
495 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
496 option_log = git_config_bool(k, v);
497 return git_diff_ui_config(k, v, cb);
500 static int read_tree_trivial(unsigned char *common, unsigned char *head,
501 unsigned char *one)
503 int i, nr_trees = 0;
504 struct tree *trees[MAX_UNPACK_TREES];
505 struct tree_desc t[MAX_UNPACK_TREES];
506 struct unpack_trees_options opts;
508 memset(&opts, 0, sizeof(opts));
509 opts.head_idx = 2;
510 opts.src_index = &the_index;
511 opts.dst_index = &the_index;
512 opts.update = 1;
513 opts.verbose_update = 1;
514 opts.trivial_merges_only = 1;
515 opts.merge = 1;
516 trees[nr_trees] = parse_tree_indirect(common);
517 if (!trees[nr_trees++])
518 return -1;
519 trees[nr_trees] = parse_tree_indirect(head);
520 if (!trees[nr_trees++])
521 return -1;
522 trees[nr_trees] = parse_tree_indirect(one);
523 if (!trees[nr_trees++])
524 return -1;
525 opts.fn = threeway_merge;
526 cache_tree_free(&active_cache_tree);
527 for (i = 0; i < nr_trees; i++) {
528 parse_tree(trees[i]);
529 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
531 if (unpack_trees(nr_trees, t, &opts))
532 return -1;
533 return 0;
536 static void write_tree_trivial(unsigned char *sha1)
538 if (write_cache_as_tree(sha1, 0, NULL))
539 die("git write-tree failed to write a tree");
542 static int try_merge_strategy(const char *strategy, struct commit_list *common,
543 const char *head_arg)
545 const char **args;
546 int i = 0, ret;
547 struct commit_list *j;
548 struct strbuf buf;
549 int index_fd;
550 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
552 index_fd = hold_locked_index(lock, 1);
553 refresh_cache(REFRESH_QUIET);
554 if (active_cache_changed &&
555 (write_cache(index_fd, active_cache, active_nr) ||
556 commit_locked_index(lock)))
557 return error("Unable to write index.");
558 rollback_lock_file(lock);
560 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
561 int clean;
562 struct commit *result;
563 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
564 int index_fd;
565 struct commit_list *reversed = NULL;
566 struct merge_options o;
568 if (remoteheads->next) {
569 error("Not handling anything other than two heads merge.");
570 return 2;
573 init_merge_options(&o);
574 if (!strcmp(strategy, "subtree"))
575 o.subtree_merge = 1;
577 o.branch1 = head_arg;
578 o.branch2 = remoteheads->item->util;
580 for (j = common; j; j = j->next)
581 commit_list_insert(j->item, &reversed);
583 index_fd = hold_locked_index(lock, 1);
584 clean = merge_recursive(&o, lookup_commit(head),
585 remoteheads->item, reversed, &result);
586 if (active_cache_changed &&
587 (write_cache(index_fd, active_cache, active_nr) ||
588 commit_locked_index(lock)))
589 die ("unable to write %s", get_index_file());
590 rollback_lock_file(lock);
591 return clean ? 0 : 1;
592 } else {
593 args = xmalloc((4 + commit_list_count(common) +
594 commit_list_count(remoteheads)) * sizeof(char *));
595 strbuf_init(&buf, 0);
596 strbuf_addf(&buf, "merge-%s", strategy);
597 args[i++] = buf.buf;
598 for (j = common; j; j = j->next)
599 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
600 args[i++] = "--";
601 args[i++] = head_arg;
602 for (j = remoteheads; j; j = j->next)
603 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
604 args[i] = NULL;
605 ret = run_command_v_opt(args, RUN_GIT_CMD);
606 strbuf_release(&buf);
607 i = 1;
608 for (j = common; j; j = j->next)
609 free((void *)args[i++]);
610 i += 2;
611 for (j = remoteheads; j; j = j->next)
612 free((void *)args[i++]);
613 free(args);
614 discard_cache();
615 if (read_cache() < 0)
616 die("failed to read the cache");
617 return -ret;
621 static void count_diff_files(struct diff_queue_struct *q,
622 struct diff_options *opt, void *data)
624 int *count = data;
626 (*count) += q->nr;
629 static int count_unmerged_entries(void)
631 const struct index_state *state = &the_index;
632 int i, ret = 0;
634 for (i = 0; i < state->cache_nr; i++)
635 if (ce_stage(state->cache[i]))
636 ret++;
638 return ret;
641 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
643 struct tree *trees[MAX_UNPACK_TREES];
644 struct unpack_trees_options opts;
645 struct tree_desc t[MAX_UNPACK_TREES];
646 int i, fd, nr_trees = 0;
647 struct dir_struct dir;
648 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
650 refresh_cache(REFRESH_QUIET);
652 fd = hold_locked_index(lock_file, 1);
654 memset(&trees, 0, sizeof(trees));
655 memset(&opts, 0, sizeof(opts));
656 memset(&t, 0, sizeof(t));
657 memset(&dir, 0, sizeof(dir));
658 dir.show_ignored = 1;
659 dir.exclude_per_dir = ".gitignore";
660 opts.dir = &dir;
662 opts.head_idx = 1;
663 opts.src_index = &the_index;
664 opts.dst_index = &the_index;
665 opts.update = 1;
666 opts.verbose_update = 1;
667 opts.merge = 1;
668 opts.fn = twoway_merge;
670 trees[nr_trees] = parse_tree_indirect(head);
671 if (!trees[nr_trees++])
672 return -1;
673 trees[nr_trees] = parse_tree_indirect(remote);
674 if (!trees[nr_trees++])
675 return -1;
676 for (i = 0; i < nr_trees; i++) {
677 parse_tree(trees[i]);
678 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
680 if (unpack_trees(nr_trees, t, &opts))
681 return -1;
682 if (write_cache(fd, active_cache, active_nr) ||
683 commit_locked_index(lock_file))
684 die("unable to write new index file");
685 return 0;
688 static void split_merge_strategies(const char *string, struct strategy **list,
689 int *nr, int *alloc)
691 char *p, *q, *buf;
693 if (!string)
694 return;
696 buf = xstrdup(string);
697 q = buf;
698 for (;;) {
699 p = strchr(q, ' ');
700 if (!p) {
701 ALLOC_GROW(*list, *nr + 1, *alloc);
702 (*list)[(*nr)++].name = xstrdup(q);
703 free(buf);
704 return;
705 } else {
706 *p = '\0';
707 ALLOC_GROW(*list, *nr + 1, *alloc);
708 (*list)[(*nr)++].name = xstrdup(q);
709 q = ++p;
714 static void add_strategies(const char *string, unsigned attr)
716 struct strategy *list = NULL;
717 int list_alloc = 0, list_nr = 0, i;
719 memset(&list, 0, sizeof(list));
720 split_merge_strategies(string, &list, &list_nr, &list_alloc);
721 if (list) {
722 for (i = 0; i < list_nr; i++)
723 append_strategy(get_strategy(list[i].name));
724 return;
726 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
727 if (all_strategy[i].attr & attr)
728 append_strategy(&all_strategy[i]);
732 static int merge_trivial(void)
734 unsigned char result_tree[20], result_commit[20];
735 struct commit_list *parent = xmalloc(sizeof(*parent));
737 write_tree_trivial(result_tree);
738 printf("Wonderful.\n");
739 parent->item = lookup_commit(head);
740 parent->next = xmalloc(sizeof(*parent->next));
741 parent->next->item = remoteheads->item;
742 parent->next->next = NULL;
743 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
744 finish(result_commit, "In-index merge");
745 drop_save();
746 return 0;
749 static int finish_automerge(struct commit_list *common,
750 unsigned char *result_tree,
751 const char *wt_strategy)
753 struct commit_list *parents = NULL, *j;
754 struct strbuf buf = STRBUF_INIT;
755 unsigned char result_commit[20];
757 free_commit_list(common);
758 if (allow_fast_forward) {
759 parents = remoteheads;
760 commit_list_insert(lookup_commit(head), &parents);
761 parents = reduce_heads(parents);
762 } else {
763 struct commit_list **pptr = &parents;
765 pptr = &commit_list_insert(lookup_commit(head),
766 pptr)->next;
767 for (j = remoteheads; j; j = j->next)
768 pptr = &commit_list_insert(j->item, pptr)->next;
770 free_commit_list(remoteheads);
771 strbuf_addch(&merge_msg, '\n');
772 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
773 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
774 finish(result_commit, buf.buf);
775 strbuf_release(&buf);
776 drop_save();
777 return 0;
780 static int suggest_conflicts(void)
782 FILE *fp;
783 int pos;
785 fp = fopen(git_path("MERGE_MSG"), "a");
786 if (!fp)
787 die("Could open %s for writing", git_path("MERGE_MSG"));
788 fprintf(fp, "\nConflicts:\n");
789 for (pos = 0; pos < active_nr; pos++) {
790 struct cache_entry *ce = active_cache[pos];
792 if (ce_stage(ce)) {
793 fprintf(fp, "\t%s\n", ce->name);
794 while (pos + 1 < active_nr &&
795 !strcmp(ce->name,
796 active_cache[pos + 1]->name))
797 pos++;
800 fclose(fp);
801 rerere();
802 printf("Automatic merge failed; "
803 "fix conflicts and then commit the result.\n");
804 return 1;
807 static struct commit *is_old_style_invocation(int argc, const char **argv)
809 struct commit *second_token = NULL;
810 if (argc > 1) {
811 unsigned char second_sha1[20];
813 if (get_sha1(argv[1], second_sha1))
814 return NULL;
815 second_token = lookup_commit_reference_gently(second_sha1, 0);
816 if (!second_token)
817 die("'%s' is not a commit", argv[1]);
818 if (hashcmp(second_token->object.sha1, head))
819 return NULL;
821 return second_token;
824 static int evaluate_result(void)
826 int cnt = 0;
827 struct rev_info rev;
829 /* Check how many files differ. */
830 init_revisions(&rev, "");
831 setup_revisions(0, NULL, &rev, NULL);
832 rev.diffopt.output_format |=
833 DIFF_FORMAT_CALLBACK;
834 rev.diffopt.format_callback = count_diff_files;
835 rev.diffopt.format_callback_data = &cnt;
836 run_diff_files(&rev, 0);
839 * Check how many unmerged entries are
840 * there.
842 cnt += count_unmerged_entries();
844 return cnt;
847 int cmd_merge(int argc, const char **argv, const char *prefix)
849 unsigned char result_tree[20];
850 struct strbuf buf;
851 const char *head_arg;
852 int flag, head_invalid = 0, i;
853 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
854 struct commit_list *common = NULL;
855 const char *best_strategy = NULL, *wt_strategy = NULL;
856 struct commit_list **remotes = &remoteheads;
858 setup_work_tree();
859 if (read_cache_unmerged())
860 die("You are in the middle of a conflicted merge.");
863 * Check if we are _not_ on a detached HEAD, i.e. if there is a
864 * current branch.
866 branch = resolve_ref("HEAD", head, 0, &flag);
867 if (branch && !prefixcmp(branch, "refs/heads/"))
868 branch += 11;
869 if (is_null_sha1(head))
870 head_invalid = 1;
872 git_config(git_merge_config, NULL);
874 /* for color.ui */
875 if (diff_use_color_default == -1)
876 diff_use_color_default = git_use_color_default;
878 argc = parse_options(argc, argv, builtin_merge_options,
879 builtin_merge_usage, 0);
881 if (squash) {
882 if (!allow_fast_forward)
883 die("You cannot combine --squash with --no-ff.");
884 option_commit = 0;
887 if (!argc)
888 usage_with_options(builtin_merge_usage,
889 builtin_merge_options);
892 * This could be traditional "merge <msg> HEAD <commit>..." and
893 * the way we can tell it is to see if the second token is HEAD,
894 * but some people might have misused the interface and used a
895 * committish that is the same as HEAD there instead.
896 * Traditional format never would have "-m" so it is an
897 * additional safety measure to check for it.
899 strbuf_init(&buf, 0);
901 if (!have_message && is_old_style_invocation(argc, argv)) {
902 strbuf_addstr(&merge_msg, argv[0]);
903 head_arg = argv[1];
904 argv += 2;
905 argc -= 2;
906 } else if (head_invalid) {
907 struct object *remote_head;
909 * If the merged head is a valid one there is no reason
910 * to forbid "git merge" into a branch yet to be born.
911 * We do the same for "git pull".
913 if (argc != 1)
914 die("Can merge only exactly one commit into "
915 "empty head");
916 if (squash)
917 die("Squash commit into empty head not supported yet");
918 if (!allow_fast_forward)
919 die("Non-fast-forward commit does not make sense into "
920 "an empty head");
921 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
922 if (!remote_head)
923 die("%s - not something we can merge", argv[0]);
924 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
925 DIE_ON_ERR);
926 reset_hard(remote_head->sha1, 0);
927 return 0;
928 } else {
929 struct strbuf msg;
931 /* We are invoked directly as the first-class UI. */
932 head_arg = "HEAD";
935 * All the rest are the commits being merged;
936 * prepare the standard merge summary message to
937 * be appended to the given message. If remote
938 * is invalid we will die later in the common
939 * codepath so we discard the error in this
940 * loop.
942 strbuf_init(&msg, 0);
943 for (i = 0; i < argc; i++)
944 merge_name(argv[i], &msg);
945 fmt_merge_msg(option_log, &msg, &merge_msg);
946 if (merge_msg.len)
947 strbuf_setlen(&merge_msg, merge_msg.len-1);
950 if (head_invalid || !argc)
951 usage_with_options(builtin_merge_usage,
952 builtin_merge_options);
954 strbuf_addstr(&buf, "merge");
955 for (i = 0; i < argc; i++)
956 strbuf_addf(&buf, " %s", argv[i]);
957 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
958 strbuf_reset(&buf);
960 for (i = 0; i < argc; i++) {
961 struct object *o;
962 struct commit *commit;
964 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
965 if (!o)
966 die("%s - not something we can merge", argv[i]);
967 commit = lookup_commit(o->sha1);
968 commit->util = (void *)argv[i];
969 remotes = &commit_list_insert(commit, remotes)->next;
971 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
972 setenv(buf.buf, argv[i], 1);
973 strbuf_reset(&buf);
976 if (!use_strategies) {
977 if (!remoteheads->next)
978 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
979 else
980 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
983 for (i = 0; i < use_strategies_nr; i++) {
984 if (use_strategies[i]->attr & NO_FAST_FORWARD)
985 allow_fast_forward = 0;
986 if (use_strategies[i]->attr & NO_TRIVIAL)
987 allow_trivial = 0;
990 if (!remoteheads->next)
991 common = get_merge_bases(lookup_commit(head),
992 remoteheads->item, 1);
993 else {
994 struct commit_list *list = remoteheads;
995 commit_list_insert(lookup_commit(head), &list);
996 common = get_octopus_merge_bases(list);
997 free(list);
1000 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1001 DIE_ON_ERR);
1003 if (!common)
1004 ; /* No common ancestors found. We need a real merge. */
1005 else if (!remoteheads->next && !common->next &&
1006 common->item == remoteheads->item) {
1008 * If head can reach all the merge then we are up to date.
1009 * but first the most common case of merging one remote.
1011 finish_up_to_date("Already up-to-date.");
1012 return 0;
1013 } else if (allow_fast_forward && !remoteheads->next &&
1014 !common->next &&
1015 !hashcmp(common->item->object.sha1, head)) {
1016 /* Again the most common case of merging one remote. */
1017 struct strbuf msg;
1018 struct object *o;
1019 char hex[41];
1021 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1023 printf("Updating %s..%s\n",
1024 hex,
1025 find_unique_abbrev(remoteheads->item->object.sha1,
1026 DEFAULT_ABBREV));
1027 strbuf_init(&msg, 0);
1028 strbuf_addstr(&msg, "Fast forward");
1029 if (have_message)
1030 strbuf_addstr(&msg,
1031 " (no commit created; -m option ignored)");
1032 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1033 0, NULL, OBJ_COMMIT);
1034 if (!o)
1035 return 1;
1037 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1038 return 1;
1040 finish(o->sha1, msg.buf);
1041 drop_save();
1042 return 0;
1043 } else if (!remoteheads->next && common->next)
1046 * We are not doing octopus and not fast forward. Need
1047 * a real merge.
1049 else if (!remoteheads->next && !common->next && option_commit) {
1051 * We are not doing octopus, not fast forward, and have
1052 * only one common.
1054 refresh_cache(REFRESH_QUIET);
1055 if (allow_trivial) {
1056 /* See if it is really trivial. */
1057 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1058 printf("Trying really trivial in-index merge...\n");
1059 if (!read_tree_trivial(common->item->object.sha1,
1060 head, remoteheads->item->object.sha1))
1061 return merge_trivial();
1062 printf("Nope.\n");
1064 } else {
1066 * An octopus. If we can reach all the remote we are up
1067 * to date.
1069 int up_to_date = 1;
1070 struct commit_list *j;
1072 for (j = remoteheads; j; j = j->next) {
1073 struct commit_list *common_one;
1076 * Here we *have* to calculate the individual
1077 * merge_bases again, otherwise "git merge HEAD^
1078 * HEAD^^" would be missed.
1080 common_one = get_merge_bases(lookup_commit(head),
1081 j->item, 1);
1082 if (hashcmp(common_one->item->object.sha1,
1083 j->item->object.sha1)) {
1084 up_to_date = 0;
1085 break;
1088 if (up_to_date) {
1089 finish_up_to_date("Already up-to-date. Yeeah!");
1090 return 0;
1094 /* We are going to make a new commit. */
1095 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1098 * At this point, we need a real merge. No matter what strategy
1099 * we use, it would operate on the index, possibly affecting the
1100 * working tree, and when resolved cleanly, have the desired
1101 * tree in the index -- this means that the index must be in
1102 * sync with the head commit. The strategies are responsible
1103 * to ensure this.
1105 if (use_strategies_nr != 1) {
1107 * Stash away the local changes so that we can try more
1108 * than one.
1110 save_state();
1111 } else {
1112 memcpy(stash, null_sha1, 20);
1115 for (i = 0; i < use_strategies_nr; i++) {
1116 int ret;
1117 if (i) {
1118 printf("Rewinding the tree to pristine...\n");
1119 restore_state();
1121 if (use_strategies_nr != 1)
1122 printf("Trying merge strategy %s...\n",
1123 use_strategies[i]->name);
1125 * Remember which strategy left the state in the working
1126 * tree.
1128 wt_strategy = use_strategies[i]->name;
1130 ret = try_merge_strategy(use_strategies[i]->name,
1131 common, head_arg);
1132 if (!option_commit && !ret) {
1133 merge_was_ok = 1;
1135 * This is necessary here just to avoid writing
1136 * the tree, but later we will *not* exit with
1137 * status code 1 because merge_was_ok is set.
1139 ret = 1;
1142 if (ret) {
1144 * The backend exits with 1 when conflicts are
1145 * left to be resolved, with 2 when it does not
1146 * handle the given merge at all.
1148 if (ret == 1) {
1149 int cnt = evaluate_result();
1151 if (best_cnt <= 0 || cnt <= best_cnt) {
1152 best_strategy = use_strategies[i]->name;
1153 best_cnt = cnt;
1156 if (merge_was_ok)
1157 break;
1158 else
1159 continue;
1162 /* Automerge succeeded. */
1163 write_tree_trivial(result_tree);
1164 automerge_was_ok = 1;
1165 break;
1169 * If we have a resulting tree, that means the strategy module
1170 * auto resolved the merge cleanly.
1172 if (automerge_was_ok)
1173 return finish_automerge(common, result_tree, wt_strategy);
1176 * Pick the result from the best strategy and have the user fix
1177 * it up.
1179 if (!best_strategy) {
1180 restore_state();
1181 if (use_strategies_nr > 1)
1182 fprintf(stderr,
1183 "No merge strategy handled the merge.\n");
1184 else
1185 fprintf(stderr, "Merge with strategy %s failed.\n",
1186 use_strategies[0]->name);
1187 return 2;
1188 } else if (best_strategy == wt_strategy)
1189 ; /* We already have its result in the working tree. */
1190 else {
1191 printf("Rewinding the tree to pristine...\n");
1192 restore_state();
1193 printf("Using the %s to prepare resolving by hand.\n",
1194 best_strategy);
1195 try_merge_strategy(best_strategy, common, head_arg);
1198 if (squash)
1199 finish(NULL, NULL);
1200 else {
1201 int fd;
1202 struct commit_list *j;
1204 for (j = remoteheads; j; j = j->next)
1205 strbuf_addf(&buf, "%s\n",
1206 sha1_to_hex(j->item->object.sha1));
1207 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1208 if (fd < 0)
1209 die("Could open %s for writing",
1210 git_path("MERGE_HEAD"));
1211 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1212 die("Could not write to %s", git_path("MERGE_HEAD"));
1213 close(fd);
1214 strbuf_addch(&merge_msg, '\n');
1215 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1216 if (fd < 0)
1217 die("Could open %s for writing", git_path("MERGE_MSG"));
1218 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1219 merge_msg.len)
1220 die("Could not write to %s", git_path("MERGE_MSG"));
1221 close(fd);
1224 if (merge_was_ok) {
1225 fprintf(stderr, "Automatic merge went well; "
1226 "stopped before committing as requested\n");
1227 return 0;
1228 } else
1229 return suggest_conflicts();