Merge branch 'maint'
[git/msvc.git] / builtin-merge.c
blob5e7910bd8da0a603dd82e7502c28a603bf80fa82
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"));
182 unlink(git_path("MERGE_MODE"));
185 static void save_state(void)
187 int len;
188 struct child_process cp;
189 struct strbuf buffer = STRBUF_INIT;
190 const char *argv[] = {"stash", "create", NULL};
192 memset(&cp, 0, sizeof(cp));
193 cp.argv = argv;
194 cp.out = -1;
195 cp.git_cmd = 1;
197 if (start_command(&cp))
198 die("could not run stash.");
199 len = strbuf_read(&buffer, cp.out, 1024);
200 close(cp.out);
202 if (finish_command(&cp) || len < 0)
203 die("stash failed");
204 else if (!len)
205 return;
206 strbuf_setlen(&buffer, buffer.len-1);
207 if (get_sha1(buffer.buf, stash))
208 die("not a valid object: %s", buffer.buf);
211 static void reset_hard(unsigned const char *sha1, int verbose)
213 int i = 0;
214 const char *args[6];
216 args[i++] = "read-tree";
217 if (verbose)
218 args[i++] = "-v";
219 args[i++] = "--reset";
220 args[i++] = "-u";
221 args[i++] = sha1_to_hex(sha1);
222 args[i] = NULL;
224 if (run_command_v_opt(args, RUN_GIT_CMD))
225 die("read-tree failed");
228 static void restore_state(void)
230 struct strbuf sb = STRBUF_INIT;
231 const char *args[] = { "stash", "apply", NULL, NULL };
233 if (is_null_sha1(stash))
234 return;
236 reset_hard(head, 1);
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 = STRBUF_INIT;
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_addstr(&out, "Squashed commit of the following:\n");
286 while ((commit = get_revision(&rev)) != NULL) {
287 strbuf_addch(&out, '\n');
288 strbuf_addf(&out, "commit %s\n",
289 sha1_to_hex(commit->object.sha1));
290 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
291 NULL, NULL, rev.date_mode, 0);
293 write(fd, out.buf, out.len);
294 close(fd);
295 strbuf_release(&out);
298 static int run_hook(const char *name)
300 struct child_process hook;
301 const char *argv[3], *env[2];
302 char index[PATH_MAX];
304 argv[0] = git_path("hooks/%s", name);
305 if (access(argv[0], X_OK) < 0)
306 return 0;
308 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
309 env[0] = index;
310 env[1] = NULL;
312 if (squash)
313 argv[1] = "1";
314 else
315 argv[1] = "0";
316 argv[2] = NULL;
318 memset(&hook, 0, sizeof(hook));
319 hook.argv = argv;
320 hook.no_stdin = 1;
321 hook.stdout_to_stderr = 1;
322 hook.env = env;
324 return run_command(&hook);
327 static void finish(const unsigned char *new_head, const char *msg)
329 struct strbuf reflog_message = STRBUF_INIT;
331 if (!msg)
332 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
333 else {
334 printf("%s\n", msg);
335 strbuf_addf(&reflog_message, "%s: %s",
336 getenv("GIT_REFLOG_ACTION"), msg);
338 if (squash) {
339 squash_message();
340 } else {
341 if (!merge_msg.len)
342 printf("No merge message -- not updating HEAD\n");
343 else {
344 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
345 update_ref(reflog_message.buf, "HEAD",
346 new_head, head, 0,
347 DIE_ON_ERR);
349 * We ignore errors in 'gc --auto', since the
350 * user should see them.
352 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
355 if (new_head && show_diffstat) {
356 struct diff_options opts;
357 diff_setup(&opts);
358 opts.output_format |=
359 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
360 opts.detect_rename = DIFF_DETECT_RENAME;
361 if (diff_use_color_default > 0)
362 DIFF_OPT_SET(&opts, COLOR_DIFF);
363 if (diff_setup_done(&opts) < 0)
364 die("diff_setup_done failed");
365 diff_tree_sha1(head, new_head, "", &opts);
366 diffcore_std(&opts);
367 diff_flush(&opts);
370 /* Run a post-merge hook */
371 run_hook("post-merge");
373 strbuf_release(&reflog_message);
376 /* Get the name for the merge commit's message. */
377 static void merge_name(const char *remote, struct strbuf *msg)
379 struct object *remote_head;
380 unsigned char branch_head[20], buf_sha[20];
381 struct strbuf buf = STRBUF_INIT;
382 const char *ptr;
383 int len, early;
385 memset(branch_head, 0, sizeof(branch_head));
386 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
387 if (!remote_head)
388 die("'%s' does not point to a commit", remote);
390 strbuf_addstr(&buf, "refs/heads/");
391 strbuf_addstr(&buf, remote);
392 resolve_ref(buf.buf, branch_head, 0, 0);
394 if (!hashcmp(remote_head->sha1, branch_head)) {
395 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
396 sha1_to_hex(branch_head), remote);
397 return;
400 /* See if remote matches <name>^^^.. or <name>~<number> */
401 for (len = 0, ptr = remote + strlen(remote);
402 remote < ptr && ptr[-1] == '^';
403 ptr--)
404 len++;
405 if (len)
406 early = 1;
407 else {
408 early = 0;
409 ptr = strrchr(remote, '~');
410 if (ptr) {
411 int seen_nonzero = 0;
413 len++; /* count ~ */
414 while (*++ptr && isdigit(*ptr)) {
415 seen_nonzero |= (*ptr != '0');
416 len++;
418 if (*ptr)
419 len = 0; /* not ...~<number> */
420 else if (seen_nonzero)
421 early = 1;
422 else if (len == 1)
423 early = 1; /* "name~" is "name~1"! */
426 if (len) {
427 struct strbuf truname = STRBUF_INIT;
428 strbuf_addstr(&truname, "refs/heads/");
429 strbuf_addstr(&truname, remote);
430 strbuf_setlen(&truname, truname.len - len);
431 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
432 strbuf_addf(msg,
433 "%s\t\tbranch '%s'%s of .\n",
434 sha1_to_hex(remote_head->sha1),
435 truname.buf + 11,
436 (early ? " (early part)" : ""));
437 return;
441 if (!strcmp(remote, "FETCH_HEAD") &&
442 !access(git_path("FETCH_HEAD"), R_OK)) {
443 FILE *fp;
444 struct strbuf line = STRBUF_INIT;
445 char *ptr;
447 fp = fopen(git_path("FETCH_HEAD"), "r");
448 if (!fp)
449 die("could not open %s for reading: %s",
450 git_path("FETCH_HEAD"), strerror(errno));
451 strbuf_getline(&line, fp, '\n');
452 fclose(fp);
453 ptr = strstr(line.buf, "\tnot-for-merge\t");
454 if (ptr)
455 strbuf_remove(&line, ptr-line.buf+1, 13);
456 strbuf_addbuf(msg, &line);
457 strbuf_release(&line);
458 return;
460 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
461 sha1_to_hex(remote_head->sha1), remote);
464 static int git_merge_config(const char *k, const char *v, void *cb)
466 if (branch && !prefixcmp(k, "branch.") &&
467 !prefixcmp(k + 7, branch) &&
468 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
469 const char **argv;
470 int argc;
471 char *buf;
473 buf = xstrdup(v);
474 argc = split_cmdline(buf, &argv);
475 if (argc < 0)
476 die("Bad branch.%s.mergeoptions string", branch);
477 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
478 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
479 argc++;
480 parse_options(argc, argv, builtin_merge_options,
481 builtin_merge_usage, 0);
482 free(buf);
485 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
486 show_diffstat = git_config_bool(k, v);
487 else if (!strcmp(k, "pull.twohead"))
488 return git_config_string(&pull_twohead, k, v);
489 else if (!strcmp(k, "pull.octopus"))
490 return git_config_string(&pull_octopus, k, v);
491 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
492 option_log = git_config_bool(k, v);
493 return git_diff_ui_config(k, v, cb);
496 static int read_tree_trivial(unsigned char *common, unsigned char *head,
497 unsigned char *one)
499 int i, nr_trees = 0;
500 struct tree *trees[MAX_UNPACK_TREES];
501 struct tree_desc t[MAX_UNPACK_TREES];
502 struct unpack_trees_options opts;
504 memset(&opts, 0, sizeof(opts));
505 opts.head_idx = 2;
506 opts.src_index = &the_index;
507 opts.dst_index = &the_index;
508 opts.update = 1;
509 opts.verbose_update = 1;
510 opts.trivial_merges_only = 1;
511 opts.merge = 1;
512 trees[nr_trees] = parse_tree_indirect(common);
513 if (!trees[nr_trees++])
514 return -1;
515 trees[nr_trees] = parse_tree_indirect(head);
516 if (!trees[nr_trees++])
517 return -1;
518 trees[nr_trees] = parse_tree_indirect(one);
519 if (!trees[nr_trees++])
520 return -1;
521 opts.fn = threeway_merge;
522 cache_tree_free(&active_cache_tree);
523 for (i = 0; i < nr_trees; i++) {
524 parse_tree(trees[i]);
525 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
527 if (unpack_trees(nr_trees, t, &opts))
528 return -1;
529 return 0;
532 static void write_tree_trivial(unsigned char *sha1)
534 if (write_cache_as_tree(sha1, 0, NULL))
535 die("git write-tree failed to write a tree");
538 static int try_merge_strategy(const char *strategy, struct commit_list *common,
539 const char *head_arg)
541 const char **args;
542 int i = 0, ret;
543 struct commit_list *j;
544 struct strbuf buf = STRBUF_INIT;
545 int index_fd;
546 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
548 index_fd = hold_locked_index(lock, 1);
549 refresh_cache(REFRESH_QUIET);
550 if (active_cache_changed &&
551 (write_cache(index_fd, active_cache, active_nr) ||
552 commit_locked_index(lock)))
553 return error("Unable to write index.");
554 rollback_lock_file(lock);
556 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
557 int clean;
558 struct commit *result;
559 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
560 int index_fd;
561 struct commit_list *reversed = NULL;
562 struct merge_options o;
564 if (remoteheads->next) {
565 error("Not handling anything other than two heads merge.");
566 return 2;
569 init_merge_options(&o);
570 if (!strcmp(strategy, "subtree"))
571 o.subtree_merge = 1;
573 o.branch1 = head_arg;
574 o.branch2 = remoteheads->item->util;
576 for (j = common; j; j = j->next)
577 commit_list_insert(j->item, &reversed);
579 index_fd = hold_locked_index(lock, 1);
580 clean = merge_recursive(&o, lookup_commit(head),
581 remoteheads->item, reversed, &result);
582 if (active_cache_changed &&
583 (write_cache(index_fd, active_cache, active_nr) ||
584 commit_locked_index(lock)))
585 die ("unable to write %s", get_index_file());
586 rollback_lock_file(lock);
587 return clean ? 0 : 1;
588 } else {
589 args = xmalloc((4 + commit_list_count(common) +
590 commit_list_count(remoteheads)) * sizeof(char *));
591 strbuf_addf(&buf, "merge-%s", strategy);
592 args[i++] = buf.buf;
593 for (j = common; j; j = j->next)
594 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
595 args[i++] = "--";
596 args[i++] = head_arg;
597 for (j = remoteheads; j; j = j->next)
598 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
599 args[i] = NULL;
600 ret = run_command_v_opt(args, RUN_GIT_CMD);
601 strbuf_release(&buf);
602 i = 1;
603 for (j = common; j; j = j->next)
604 free((void *)args[i++]);
605 i += 2;
606 for (j = remoteheads; j; j = j->next)
607 free((void *)args[i++]);
608 free(args);
609 discard_cache();
610 if (read_cache() < 0)
611 die("failed to read the cache");
612 return -ret;
616 static void count_diff_files(struct diff_queue_struct *q,
617 struct diff_options *opt, void *data)
619 int *count = data;
621 (*count) += q->nr;
624 static int count_unmerged_entries(void)
626 const struct index_state *state = &the_index;
627 int i, ret = 0;
629 for (i = 0; i < state->cache_nr; i++)
630 if (ce_stage(state->cache[i]))
631 ret++;
633 return ret;
636 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
638 struct tree *trees[MAX_UNPACK_TREES];
639 struct unpack_trees_options opts;
640 struct tree_desc t[MAX_UNPACK_TREES];
641 int i, fd, nr_trees = 0;
642 struct dir_struct dir;
643 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
645 refresh_cache(REFRESH_QUIET);
647 fd = hold_locked_index(lock_file, 1);
649 memset(&trees, 0, sizeof(trees));
650 memset(&opts, 0, sizeof(opts));
651 memset(&t, 0, sizeof(t));
652 memset(&dir, 0, sizeof(dir));
653 dir.show_ignored = 1;
654 dir.exclude_per_dir = ".gitignore";
655 opts.dir = &dir;
657 opts.head_idx = 1;
658 opts.src_index = &the_index;
659 opts.dst_index = &the_index;
660 opts.update = 1;
661 opts.verbose_update = 1;
662 opts.merge = 1;
663 opts.fn = twoway_merge;
665 trees[nr_trees] = parse_tree_indirect(head);
666 if (!trees[nr_trees++])
667 return -1;
668 trees[nr_trees] = parse_tree_indirect(remote);
669 if (!trees[nr_trees++])
670 return -1;
671 for (i = 0; i < nr_trees; i++) {
672 parse_tree(trees[i]);
673 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
675 if (unpack_trees(nr_trees, t, &opts))
676 return -1;
677 if (write_cache(fd, active_cache, active_nr) ||
678 commit_locked_index(lock_file))
679 die("unable to write new index file");
680 return 0;
683 static void split_merge_strategies(const char *string, struct strategy **list,
684 int *nr, int *alloc)
686 char *p, *q, *buf;
688 if (!string)
689 return;
691 buf = xstrdup(string);
692 q = buf;
693 for (;;) {
694 p = strchr(q, ' ');
695 if (!p) {
696 ALLOC_GROW(*list, *nr + 1, *alloc);
697 (*list)[(*nr)++].name = xstrdup(q);
698 free(buf);
699 return;
700 } else {
701 *p = '\0';
702 ALLOC_GROW(*list, *nr + 1, *alloc);
703 (*list)[(*nr)++].name = xstrdup(q);
704 q = ++p;
709 static void add_strategies(const char *string, unsigned attr)
711 struct strategy *list = NULL;
712 int list_alloc = 0, list_nr = 0, i;
714 memset(&list, 0, sizeof(list));
715 split_merge_strategies(string, &list, &list_nr, &list_alloc);
716 if (list) {
717 for (i = 0; i < list_nr; i++)
718 append_strategy(get_strategy(list[i].name));
719 return;
721 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
722 if (all_strategy[i].attr & attr)
723 append_strategy(&all_strategy[i]);
727 static int merge_trivial(void)
729 unsigned char result_tree[20], result_commit[20];
730 struct commit_list *parent = xmalloc(sizeof(*parent));
732 write_tree_trivial(result_tree);
733 printf("Wonderful.\n");
734 parent->item = lookup_commit(head);
735 parent->next = xmalloc(sizeof(*parent->next));
736 parent->next->item = remoteheads->item;
737 parent->next->next = NULL;
738 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
739 finish(result_commit, "In-index merge");
740 drop_save();
741 return 0;
744 static int finish_automerge(struct commit_list *common,
745 unsigned char *result_tree,
746 const char *wt_strategy)
748 struct commit_list *parents = NULL, *j;
749 struct strbuf buf = STRBUF_INIT;
750 unsigned char result_commit[20];
752 free_commit_list(common);
753 if (allow_fast_forward) {
754 parents = remoteheads;
755 commit_list_insert(lookup_commit(head), &parents);
756 parents = reduce_heads(parents);
757 } else {
758 struct commit_list **pptr = &parents;
760 pptr = &commit_list_insert(lookup_commit(head),
761 pptr)->next;
762 for (j = remoteheads; j; j = j->next)
763 pptr = &commit_list_insert(j->item, pptr)->next;
765 free_commit_list(remoteheads);
766 strbuf_addch(&merge_msg, '\n');
767 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
768 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
769 finish(result_commit, buf.buf);
770 strbuf_release(&buf);
771 drop_save();
772 return 0;
775 static int suggest_conflicts(void)
777 FILE *fp;
778 int pos;
780 fp = fopen(git_path("MERGE_MSG"), "a");
781 if (!fp)
782 die("Could open %s for writing", git_path("MERGE_MSG"));
783 fprintf(fp, "\nConflicts:\n");
784 for (pos = 0; pos < active_nr; pos++) {
785 struct cache_entry *ce = active_cache[pos];
787 if (ce_stage(ce)) {
788 fprintf(fp, "\t%s\n", ce->name);
789 while (pos + 1 < active_nr &&
790 !strcmp(ce->name,
791 active_cache[pos + 1]->name))
792 pos++;
795 fclose(fp);
796 rerere();
797 printf("Automatic merge failed; "
798 "fix conflicts and then commit the result.\n");
799 return 1;
802 static struct commit *is_old_style_invocation(int argc, const char **argv)
804 struct commit *second_token = NULL;
805 if (argc > 1) {
806 unsigned char second_sha1[20];
808 if (get_sha1(argv[1], second_sha1))
809 return NULL;
810 second_token = lookup_commit_reference_gently(second_sha1, 0);
811 if (!second_token)
812 die("'%s' is not a commit", argv[1]);
813 if (hashcmp(second_token->object.sha1, head))
814 return NULL;
816 return second_token;
819 static int evaluate_result(void)
821 int cnt = 0;
822 struct rev_info rev;
824 /* Check how many files differ. */
825 init_revisions(&rev, "");
826 setup_revisions(0, NULL, &rev, NULL);
827 rev.diffopt.output_format |=
828 DIFF_FORMAT_CALLBACK;
829 rev.diffopt.format_callback = count_diff_files;
830 rev.diffopt.format_callback_data = &cnt;
831 run_diff_files(&rev, 0);
834 * Check how many unmerged entries are
835 * there.
837 cnt += count_unmerged_entries();
839 return cnt;
842 int cmd_merge(int argc, const char **argv, const char *prefix)
844 unsigned char result_tree[20];
845 struct strbuf buf = STRBUF_INIT;
846 const char *head_arg;
847 int flag, head_invalid = 0, i;
848 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
849 struct commit_list *common = NULL;
850 const char *best_strategy = NULL, *wt_strategy = NULL;
851 struct commit_list **remotes = &remoteheads;
853 setup_work_tree();
854 if (read_cache_unmerged())
855 die("You are in the middle of a conflicted merge.");
858 * Check if we are _not_ on a detached HEAD, i.e. if there is a
859 * current branch.
861 branch = resolve_ref("HEAD", head, 0, &flag);
862 if (branch && !prefixcmp(branch, "refs/heads/"))
863 branch += 11;
864 if (is_null_sha1(head))
865 head_invalid = 1;
867 git_config(git_merge_config, NULL);
869 /* for color.ui */
870 if (diff_use_color_default == -1)
871 diff_use_color_default = git_use_color_default;
873 argc = parse_options(argc, argv, builtin_merge_options,
874 builtin_merge_usage, 0);
876 if (squash) {
877 if (!allow_fast_forward)
878 die("You cannot combine --squash with --no-ff.");
879 option_commit = 0;
882 if (!argc)
883 usage_with_options(builtin_merge_usage,
884 builtin_merge_options);
887 * This could be traditional "merge <msg> HEAD <commit>..." and
888 * the way we can tell it is to see if the second token is HEAD,
889 * but some people might have misused the interface and used a
890 * committish that is the same as HEAD there instead.
891 * Traditional format never would have "-m" so it is an
892 * additional safety measure to check for it.
895 if (!have_message && is_old_style_invocation(argc, argv)) {
896 strbuf_addstr(&merge_msg, argv[0]);
897 head_arg = argv[1];
898 argv += 2;
899 argc -= 2;
900 } else if (head_invalid) {
901 struct object *remote_head;
903 * If the merged head is a valid one there is no reason
904 * to forbid "git merge" into a branch yet to be born.
905 * We do the same for "git pull".
907 if (argc != 1)
908 die("Can merge only exactly one commit into "
909 "empty head");
910 if (squash)
911 die("Squash commit into empty head not supported yet");
912 if (!allow_fast_forward)
913 die("Non-fast-forward commit does not make sense into "
914 "an empty head");
915 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
916 if (!remote_head)
917 die("%s - not something we can merge", argv[0]);
918 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
919 DIE_ON_ERR);
920 reset_hard(remote_head->sha1, 0);
921 return 0;
922 } else {
923 struct strbuf msg = STRBUF_INIT;
925 /* We are invoked directly as the first-class UI. */
926 head_arg = "HEAD";
929 * All the rest are the commits being merged;
930 * prepare the standard merge summary message to
931 * be appended to the given message. If remote
932 * is invalid we will die later in the common
933 * codepath so we discard the error in this
934 * loop.
936 for (i = 0; i < argc; i++)
937 merge_name(argv[i], &msg);
938 fmt_merge_msg(option_log, &msg, &merge_msg);
939 if (merge_msg.len)
940 strbuf_setlen(&merge_msg, merge_msg.len-1);
943 if (head_invalid || !argc)
944 usage_with_options(builtin_merge_usage,
945 builtin_merge_options);
947 strbuf_addstr(&buf, "merge");
948 for (i = 0; i < argc; i++)
949 strbuf_addf(&buf, " %s", argv[i]);
950 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
951 strbuf_reset(&buf);
953 for (i = 0; i < argc; i++) {
954 struct object *o;
955 struct commit *commit;
957 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
958 if (!o)
959 die("%s - not something we can merge", argv[i]);
960 commit = lookup_commit(o->sha1);
961 commit->util = (void *)argv[i];
962 remotes = &commit_list_insert(commit, remotes)->next;
964 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
965 setenv(buf.buf, argv[i], 1);
966 strbuf_reset(&buf);
969 if (!use_strategies) {
970 if (!remoteheads->next)
971 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
972 else
973 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
976 for (i = 0; i < use_strategies_nr; i++) {
977 if (use_strategies[i]->attr & NO_FAST_FORWARD)
978 allow_fast_forward = 0;
979 if (use_strategies[i]->attr & NO_TRIVIAL)
980 allow_trivial = 0;
983 if (!remoteheads->next)
984 common = get_merge_bases(lookup_commit(head),
985 remoteheads->item, 1);
986 else {
987 struct commit_list *list = remoteheads;
988 commit_list_insert(lookup_commit(head), &list);
989 common = get_octopus_merge_bases(list);
990 free(list);
993 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
994 DIE_ON_ERR);
996 if (!common)
997 ; /* No common ancestors found. We need a real merge. */
998 else if (!remoteheads->next && !common->next &&
999 common->item == remoteheads->item) {
1001 * If head can reach all the merge then we are up to date.
1002 * but first the most common case of merging one remote.
1004 finish_up_to_date("Already up-to-date.");
1005 return 0;
1006 } else if (allow_fast_forward && !remoteheads->next &&
1007 !common->next &&
1008 !hashcmp(common->item->object.sha1, head)) {
1009 /* Again the most common case of merging one remote. */
1010 struct strbuf msg = STRBUF_INIT;
1011 struct object *o;
1012 char hex[41];
1014 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1016 printf("Updating %s..%s\n",
1017 hex,
1018 find_unique_abbrev(remoteheads->item->object.sha1,
1019 DEFAULT_ABBREV));
1020 strbuf_addstr(&msg, "Fast forward");
1021 if (have_message)
1022 strbuf_addstr(&msg,
1023 " (no commit created; -m option ignored)");
1024 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1025 0, NULL, OBJ_COMMIT);
1026 if (!o)
1027 return 1;
1029 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1030 return 1;
1032 finish(o->sha1, msg.buf);
1033 drop_save();
1034 return 0;
1035 } else if (!remoteheads->next && common->next)
1038 * We are not doing octopus and not fast forward. Need
1039 * a real merge.
1041 else if (!remoteheads->next && !common->next && option_commit) {
1043 * We are not doing octopus, not fast forward, and have
1044 * only one common.
1046 refresh_cache(REFRESH_QUIET);
1047 if (allow_trivial) {
1048 /* See if it is really trivial. */
1049 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1050 printf("Trying really trivial in-index merge...\n");
1051 if (!read_tree_trivial(common->item->object.sha1,
1052 head, remoteheads->item->object.sha1))
1053 return merge_trivial();
1054 printf("Nope.\n");
1056 } else {
1058 * An octopus. If we can reach all the remote we are up
1059 * to date.
1061 int up_to_date = 1;
1062 struct commit_list *j;
1064 for (j = remoteheads; j; j = j->next) {
1065 struct commit_list *common_one;
1068 * Here we *have* to calculate the individual
1069 * merge_bases again, otherwise "git merge HEAD^
1070 * HEAD^^" would be missed.
1072 common_one = get_merge_bases(lookup_commit(head),
1073 j->item, 1);
1074 if (hashcmp(common_one->item->object.sha1,
1075 j->item->object.sha1)) {
1076 up_to_date = 0;
1077 break;
1080 if (up_to_date) {
1081 finish_up_to_date("Already up-to-date. Yeeah!");
1082 return 0;
1086 /* We are going to make a new commit. */
1087 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1090 * At this point, we need a real merge. No matter what strategy
1091 * we use, it would operate on the index, possibly affecting the
1092 * working tree, and when resolved cleanly, have the desired
1093 * tree in the index -- this means that the index must be in
1094 * sync with the head commit. The strategies are responsible
1095 * to ensure this.
1097 if (use_strategies_nr != 1) {
1099 * Stash away the local changes so that we can try more
1100 * than one.
1102 save_state();
1103 } else {
1104 memcpy(stash, null_sha1, 20);
1107 for (i = 0; i < use_strategies_nr; i++) {
1108 int ret;
1109 if (i) {
1110 printf("Rewinding the tree to pristine...\n");
1111 restore_state();
1113 if (use_strategies_nr != 1)
1114 printf("Trying merge strategy %s...\n",
1115 use_strategies[i]->name);
1117 * Remember which strategy left the state in the working
1118 * tree.
1120 wt_strategy = use_strategies[i]->name;
1122 ret = try_merge_strategy(use_strategies[i]->name,
1123 common, head_arg);
1124 if (!option_commit && !ret) {
1125 merge_was_ok = 1;
1127 * This is necessary here just to avoid writing
1128 * the tree, but later we will *not* exit with
1129 * status code 1 because merge_was_ok is set.
1131 ret = 1;
1134 if (ret) {
1136 * The backend exits with 1 when conflicts are
1137 * left to be resolved, with 2 when it does not
1138 * handle the given merge at all.
1140 if (ret == 1) {
1141 int cnt = evaluate_result();
1143 if (best_cnt <= 0 || cnt <= best_cnt) {
1144 best_strategy = use_strategies[i]->name;
1145 best_cnt = cnt;
1148 if (merge_was_ok)
1149 break;
1150 else
1151 continue;
1154 /* Automerge succeeded. */
1155 write_tree_trivial(result_tree);
1156 automerge_was_ok = 1;
1157 break;
1161 * If we have a resulting tree, that means the strategy module
1162 * auto resolved the merge cleanly.
1164 if (automerge_was_ok)
1165 return finish_automerge(common, result_tree, wt_strategy);
1168 * Pick the result from the best strategy and have the user fix
1169 * it up.
1171 if (!best_strategy) {
1172 restore_state();
1173 if (use_strategies_nr > 1)
1174 fprintf(stderr,
1175 "No merge strategy handled the merge.\n");
1176 else
1177 fprintf(stderr, "Merge with strategy %s failed.\n",
1178 use_strategies[0]->name);
1179 return 2;
1180 } else if (best_strategy == wt_strategy)
1181 ; /* We already have its result in the working tree. */
1182 else {
1183 printf("Rewinding the tree to pristine...\n");
1184 restore_state();
1185 printf("Using the %s to prepare resolving by hand.\n",
1186 best_strategy);
1187 try_merge_strategy(best_strategy, common, head_arg);
1190 if (squash)
1191 finish(NULL, NULL);
1192 else {
1193 int fd;
1194 struct commit_list *j;
1196 for (j = remoteheads; j; j = j->next)
1197 strbuf_addf(&buf, "%s\n",
1198 sha1_to_hex(j->item->object.sha1));
1199 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1200 if (fd < 0)
1201 die("Could open %s for writing",
1202 git_path("MERGE_HEAD"));
1203 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1204 die("Could not write to %s", git_path("MERGE_HEAD"));
1205 close(fd);
1206 strbuf_addch(&merge_msg, '\n');
1207 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1208 if (fd < 0)
1209 die("Could open %s for writing", git_path("MERGE_MSG"));
1210 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1211 merge_msg.len)
1212 die("Could not write to %s", git_path("MERGE_MSG"));
1213 close(fd);
1214 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1215 if (fd < 0)
1216 die("Could open %s for writing", git_path("MERGE_MODE"));
1217 strbuf_reset(&buf);
1218 if (!allow_fast_forward)
1219 strbuf_addf(&buf, "no-ff");
1220 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1221 die("Could not write to %s", git_path("MERGE_MODE"));
1222 close(fd);
1225 if (merge_was_ok) {
1226 fprintf(stderr, "Automatic merge went well; "
1227 "stopped before committing as requested\n");
1228 return 0;
1229 } else
1230 return suggest_conflicts();