Merge branch 'maint'
[git/jnareb-git.git] / builtin-merge.c
blob5e2b7f12c35ab1bfebda66f7ee9180c68e7f23c4
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 = STRBUF_INIT;
230 const char *args[] = { "stash", "apply", NULL, NULL };
232 if (is_null_sha1(stash))
233 return;
235 reset_hard(head, 1);
237 args[2] = sha1_to_hex(stash);
240 * It is OK to ignore error here, for example when there was
241 * nothing to restore.
243 run_command_v_opt(args, RUN_GIT_CMD);
245 strbuf_release(&sb);
246 refresh_cache(REFRESH_QUIET);
249 /* This is called when no merge was necessary. */
250 static void finish_up_to_date(const char *msg)
252 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
253 drop_save();
256 static void squash_message(void)
258 struct rev_info rev;
259 struct commit *commit;
260 struct strbuf out = STRBUF_INIT;
261 struct commit_list *j;
262 int fd;
264 printf("Squash commit -- not updating HEAD\n");
265 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
266 if (fd < 0)
267 die("Could not write to %s", git_path("SQUASH_MSG"));
269 init_revisions(&rev, NULL);
270 rev.ignore_merges = 1;
271 rev.commit_format = CMIT_FMT_MEDIUM;
273 commit = lookup_commit(head);
274 commit->object.flags |= UNINTERESTING;
275 add_pending_object(&rev, &commit->object, NULL);
277 for (j = remoteheads; j; j = j->next)
278 add_pending_object(&rev, &j->item->object, NULL);
280 setup_revisions(0, NULL, &rev, NULL);
281 if (prepare_revision_walk(&rev))
282 die("revision walk setup failed");
284 strbuf_addstr(&out, "Squashed commit of the following:\n");
285 while ((commit = get_revision(&rev)) != NULL) {
286 strbuf_addch(&out, '\n');
287 strbuf_addf(&out, "commit %s\n",
288 sha1_to_hex(commit->object.sha1));
289 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
290 NULL, NULL, rev.date_mode, 0);
292 write(fd, out.buf, out.len);
293 close(fd);
294 strbuf_release(&out);
297 static int run_hook(const char *name)
299 struct child_process hook;
300 const char *argv[3], *env[2];
301 char index[PATH_MAX];
303 argv[0] = git_path("hooks/%s", name);
304 if (access(argv[0], X_OK) < 0)
305 return 0;
307 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
308 env[0] = index;
309 env[1] = NULL;
311 if (squash)
312 argv[1] = "1";
313 else
314 argv[1] = "0";
315 argv[2] = NULL;
317 memset(&hook, 0, sizeof(hook));
318 hook.argv = argv;
319 hook.no_stdin = 1;
320 hook.stdout_to_stderr = 1;
321 hook.env = env;
323 return run_command(&hook);
326 static void finish(const unsigned char *new_head, const char *msg)
328 struct strbuf reflog_message = STRBUF_INIT;
330 if (!msg)
331 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
332 else {
333 printf("%s\n", msg);
334 strbuf_addf(&reflog_message, "%s: %s",
335 getenv("GIT_REFLOG_ACTION"), msg);
337 if (squash) {
338 squash_message();
339 } else {
340 if (!merge_msg.len)
341 printf("No merge message -- not updating HEAD\n");
342 else {
343 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
344 update_ref(reflog_message.buf, "HEAD",
345 new_head, head, 0,
346 DIE_ON_ERR);
348 * We ignore errors in 'gc --auto', since the
349 * user should see them.
351 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
354 if (new_head && show_diffstat) {
355 struct diff_options opts;
356 diff_setup(&opts);
357 opts.output_format |=
358 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
359 opts.detect_rename = DIFF_DETECT_RENAME;
360 if (diff_use_color_default > 0)
361 DIFF_OPT_SET(&opts, COLOR_DIFF);
362 if (diff_setup_done(&opts) < 0)
363 die("diff_setup_done failed");
364 diff_tree_sha1(head, new_head, "", &opts);
365 diffcore_std(&opts);
366 diff_flush(&opts);
369 /* Run a post-merge hook */
370 run_hook("post-merge");
372 strbuf_release(&reflog_message);
375 /* Get the name for the merge commit's message. */
376 static void merge_name(const char *remote, struct strbuf *msg)
378 struct object *remote_head;
379 unsigned char branch_head[20], buf_sha[20];
380 struct strbuf buf = STRBUF_INIT;
381 const char *ptr;
382 int len, early;
384 memset(branch_head, 0, sizeof(branch_head));
385 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
386 if (!remote_head)
387 die("'%s' does not point to a commit", remote);
389 strbuf_addstr(&buf, "refs/heads/");
390 strbuf_addstr(&buf, remote);
391 resolve_ref(buf.buf, branch_head, 0, 0);
393 if (!hashcmp(remote_head->sha1, branch_head)) {
394 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
395 sha1_to_hex(branch_head), remote);
396 return;
399 /* See if remote matches <name>^^^.. or <name>~<number> */
400 for (len = 0, ptr = remote + strlen(remote);
401 remote < ptr && ptr[-1] == '^';
402 ptr--)
403 len++;
404 if (len)
405 early = 1;
406 else {
407 early = 0;
408 ptr = strrchr(remote, '~');
409 if (ptr) {
410 int seen_nonzero = 0;
412 len++; /* count ~ */
413 while (*++ptr && isdigit(*ptr)) {
414 seen_nonzero |= (*ptr != '0');
415 len++;
417 if (*ptr)
418 len = 0; /* not ...~<number> */
419 else if (seen_nonzero)
420 early = 1;
421 else if (len == 1)
422 early = 1; /* "name~" is "name~1"! */
425 if (len) {
426 struct strbuf truname = STRBUF_INIT;
427 strbuf_addstr(&truname, "refs/heads/");
428 strbuf_addstr(&truname, remote);
429 strbuf_setlen(&truname, truname.len - len);
430 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
431 strbuf_addf(msg,
432 "%s\t\tbranch '%s'%s of .\n",
433 sha1_to_hex(remote_head->sha1),
434 truname.buf + 11,
435 (early ? " (early part)" : ""));
436 return;
440 if (!strcmp(remote, "FETCH_HEAD") &&
441 !access(git_path("FETCH_HEAD"), R_OK)) {
442 FILE *fp;
443 struct strbuf line = STRBUF_INIT;
444 char *ptr;
446 fp = fopen(git_path("FETCH_HEAD"), "r");
447 if (!fp)
448 die("could not open %s for reading: %s",
449 git_path("FETCH_HEAD"), strerror(errno));
450 strbuf_getline(&line, fp, '\n');
451 fclose(fp);
452 ptr = strstr(line.buf, "\tnot-for-merge\t");
453 if (ptr)
454 strbuf_remove(&line, ptr-line.buf+1, 13);
455 strbuf_addbuf(msg, &line);
456 strbuf_release(&line);
457 return;
459 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
460 sha1_to_hex(remote_head->sha1), remote);
463 static int git_merge_config(const char *k, const char *v, void *cb)
465 if (branch && !prefixcmp(k, "branch.") &&
466 !prefixcmp(k + 7, branch) &&
467 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
468 const char **argv;
469 int argc;
470 char *buf;
472 buf = xstrdup(v);
473 argc = split_cmdline(buf, &argv);
474 if (argc < 0)
475 die("Bad branch.%s.mergeoptions string", branch);
476 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
477 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
478 argc++;
479 parse_options(argc, argv, builtin_merge_options,
480 builtin_merge_usage, 0);
481 free(buf);
484 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
485 show_diffstat = git_config_bool(k, v);
486 else if (!strcmp(k, "pull.twohead"))
487 return git_config_string(&pull_twohead, k, v);
488 else if (!strcmp(k, "pull.octopus"))
489 return git_config_string(&pull_octopus, k, v);
490 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
491 option_log = git_config_bool(k, v);
492 return git_diff_ui_config(k, v, cb);
495 static int read_tree_trivial(unsigned char *common, unsigned char *head,
496 unsigned char *one)
498 int i, nr_trees = 0;
499 struct tree *trees[MAX_UNPACK_TREES];
500 struct tree_desc t[MAX_UNPACK_TREES];
501 struct unpack_trees_options opts;
503 memset(&opts, 0, sizeof(opts));
504 opts.head_idx = 2;
505 opts.src_index = &the_index;
506 opts.dst_index = &the_index;
507 opts.update = 1;
508 opts.verbose_update = 1;
509 opts.trivial_merges_only = 1;
510 opts.merge = 1;
511 trees[nr_trees] = parse_tree_indirect(common);
512 if (!trees[nr_trees++])
513 return -1;
514 trees[nr_trees] = parse_tree_indirect(head);
515 if (!trees[nr_trees++])
516 return -1;
517 trees[nr_trees] = parse_tree_indirect(one);
518 if (!trees[nr_trees++])
519 return -1;
520 opts.fn = threeway_merge;
521 cache_tree_free(&active_cache_tree);
522 for (i = 0; i < nr_trees; i++) {
523 parse_tree(trees[i]);
524 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
526 if (unpack_trees(nr_trees, t, &opts))
527 return -1;
528 return 0;
531 static void write_tree_trivial(unsigned char *sha1)
533 if (write_cache_as_tree(sha1, 0, NULL))
534 die("git write-tree failed to write a tree");
537 static int try_merge_strategy(const char *strategy, struct commit_list *common,
538 const char *head_arg)
540 const char **args;
541 int i = 0, ret;
542 struct commit_list *j;
543 struct strbuf buf = STRBUF_INIT;
544 int index_fd;
545 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
547 index_fd = hold_locked_index(lock, 1);
548 refresh_cache(REFRESH_QUIET);
549 if (active_cache_changed &&
550 (write_cache(index_fd, active_cache, active_nr) ||
551 commit_locked_index(lock)))
552 return error("Unable to write index.");
553 rollback_lock_file(lock);
555 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
556 int clean;
557 struct commit *result;
558 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
559 int index_fd;
560 struct commit_list *reversed = NULL;
561 struct merge_options o;
563 if (remoteheads->next) {
564 error("Not handling anything other than two heads merge.");
565 return 2;
568 init_merge_options(&o);
569 if (!strcmp(strategy, "subtree"))
570 o.subtree_merge = 1;
572 o.branch1 = head_arg;
573 o.branch2 = remoteheads->item->util;
575 for (j = common; j; j = j->next)
576 commit_list_insert(j->item, &reversed);
578 index_fd = hold_locked_index(lock, 1);
579 clean = merge_recursive(&o, lookup_commit(head),
580 remoteheads->item, reversed, &result);
581 if (active_cache_changed &&
582 (write_cache(index_fd, active_cache, active_nr) ||
583 commit_locked_index(lock)))
584 die ("unable to write %s", get_index_file());
585 rollback_lock_file(lock);
586 return clean ? 0 : 1;
587 } else {
588 args = xmalloc((4 + commit_list_count(common) +
589 commit_list_count(remoteheads)) * sizeof(char *));
590 strbuf_addf(&buf, "merge-%s", strategy);
591 args[i++] = buf.buf;
592 for (j = common; j; j = j->next)
593 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
594 args[i++] = "--";
595 args[i++] = head_arg;
596 for (j = remoteheads; j; j = j->next)
597 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
598 args[i] = NULL;
599 ret = run_command_v_opt(args, RUN_GIT_CMD);
600 strbuf_release(&buf);
601 i = 1;
602 for (j = common; j; j = j->next)
603 free((void *)args[i++]);
604 i += 2;
605 for (j = remoteheads; j; j = j->next)
606 free((void *)args[i++]);
607 free(args);
608 discard_cache();
609 if (read_cache() < 0)
610 die("failed to read the cache");
611 return -ret;
615 static void count_diff_files(struct diff_queue_struct *q,
616 struct diff_options *opt, void *data)
618 int *count = data;
620 (*count) += q->nr;
623 static int count_unmerged_entries(void)
625 const struct index_state *state = &the_index;
626 int i, ret = 0;
628 for (i = 0; i < state->cache_nr; i++)
629 if (ce_stage(state->cache[i]))
630 ret++;
632 return ret;
635 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
637 struct tree *trees[MAX_UNPACK_TREES];
638 struct unpack_trees_options opts;
639 struct tree_desc t[MAX_UNPACK_TREES];
640 int i, fd, nr_trees = 0;
641 struct dir_struct dir;
642 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
644 refresh_cache(REFRESH_QUIET);
646 fd = hold_locked_index(lock_file, 1);
648 memset(&trees, 0, sizeof(trees));
649 memset(&opts, 0, sizeof(opts));
650 memset(&t, 0, sizeof(t));
651 memset(&dir, 0, sizeof(dir));
652 dir.show_ignored = 1;
653 dir.exclude_per_dir = ".gitignore";
654 opts.dir = &dir;
656 opts.head_idx = 1;
657 opts.src_index = &the_index;
658 opts.dst_index = &the_index;
659 opts.update = 1;
660 opts.verbose_update = 1;
661 opts.merge = 1;
662 opts.fn = twoway_merge;
664 trees[nr_trees] = parse_tree_indirect(head);
665 if (!trees[nr_trees++])
666 return -1;
667 trees[nr_trees] = parse_tree_indirect(remote);
668 if (!trees[nr_trees++])
669 return -1;
670 for (i = 0; i < nr_trees; i++) {
671 parse_tree(trees[i]);
672 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
674 if (unpack_trees(nr_trees, t, &opts))
675 return -1;
676 if (write_cache(fd, active_cache, active_nr) ||
677 commit_locked_index(lock_file))
678 die("unable to write new index file");
679 return 0;
682 static void split_merge_strategies(const char *string, struct strategy **list,
683 int *nr, int *alloc)
685 char *p, *q, *buf;
687 if (!string)
688 return;
690 buf = xstrdup(string);
691 q = buf;
692 for (;;) {
693 p = strchr(q, ' ');
694 if (!p) {
695 ALLOC_GROW(*list, *nr + 1, *alloc);
696 (*list)[(*nr)++].name = xstrdup(q);
697 free(buf);
698 return;
699 } else {
700 *p = '\0';
701 ALLOC_GROW(*list, *nr + 1, *alloc);
702 (*list)[(*nr)++].name = xstrdup(q);
703 q = ++p;
708 static void add_strategies(const char *string, unsigned attr)
710 struct strategy *list = NULL;
711 int list_alloc = 0, list_nr = 0, i;
713 memset(&list, 0, sizeof(list));
714 split_merge_strategies(string, &list, &list_nr, &list_alloc);
715 if (list) {
716 for (i = 0; i < list_nr; i++)
717 append_strategy(get_strategy(list[i].name));
718 return;
720 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
721 if (all_strategy[i].attr & attr)
722 append_strategy(&all_strategy[i]);
726 static int merge_trivial(void)
728 unsigned char result_tree[20], result_commit[20];
729 struct commit_list *parent = xmalloc(sizeof(*parent));
731 write_tree_trivial(result_tree);
732 printf("Wonderful.\n");
733 parent->item = lookup_commit(head);
734 parent->next = xmalloc(sizeof(*parent->next));
735 parent->next->item = remoteheads->item;
736 parent->next->next = NULL;
737 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
738 finish(result_commit, "In-index merge");
739 drop_save();
740 return 0;
743 static int finish_automerge(struct commit_list *common,
744 unsigned char *result_tree,
745 const char *wt_strategy)
747 struct commit_list *parents = NULL, *j;
748 struct strbuf buf = STRBUF_INIT;
749 unsigned char result_commit[20];
751 free_commit_list(common);
752 if (allow_fast_forward) {
753 parents = remoteheads;
754 commit_list_insert(lookup_commit(head), &parents);
755 parents = reduce_heads(parents);
756 } else {
757 struct commit_list **pptr = &parents;
759 pptr = &commit_list_insert(lookup_commit(head),
760 pptr)->next;
761 for (j = remoteheads; j; j = j->next)
762 pptr = &commit_list_insert(j->item, pptr)->next;
764 free_commit_list(remoteheads);
765 strbuf_addch(&merge_msg, '\n');
766 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
767 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
768 finish(result_commit, buf.buf);
769 strbuf_release(&buf);
770 drop_save();
771 return 0;
774 static int suggest_conflicts(void)
776 FILE *fp;
777 int pos;
779 fp = fopen(git_path("MERGE_MSG"), "a");
780 if (!fp)
781 die("Could open %s for writing", git_path("MERGE_MSG"));
782 fprintf(fp, "\nConflicts:\n");
783 for (pos = 0; pos < active_nr; pos++) {
784 struct cache_entry *ce = active_cache[pos];
786 if (ce_stage(ce)) {
787 fprintf(fp, "\t%s\n", ce->name);
788 while (pos + 1 < active_nr &&
789 !strcmp(ce->name,
790 active_cache[pos + 1]->name))
791 pos++;
794 fclose(fp);
795 rerere();
796 printf("Automatic merge failed; "
797 "fix conflicts and then commit the result.\n");
798 return 1;
801 static struct commit *is_old_style_invocation(int argc, const char **argv)
803 struct commit *second_token = NULL;
804 if (argc > 1) {
805 unsigned char second_sha1[20];
807 if (get_sha1(argv[1], second_sha1))
808 return NULL;
809 second_token = lookup_commit_reference_gently(second_sha1, 0);
810 if (!second_token)
811 die("'%s' is not a commit", argv[1]);
812 if (hashcmp(second_token->object.sha1, head))
813 return NULL;
815 return second_token;
818 static int evaluate_result(void)
820 int cnt = 0;
821 struct rev_info rev;
823 /* Check how many files differ. */
824 init_revisions(&rev, "");
825 setup_revisions(0, NULL, &rev, NULL);
826 rev.diffopt.output_format |=
827 DIFF_FORMAT_CALLBACK;
828 rev.diffopt.format_callback = count_diff_files;
829 rev.diffopt.format_callback_data = &cnt;
830 run_diff_files(&rev, 0);
833 * Check how many unmerged entries are
834 * there.
836 cnt += count_unmerged_entries();
838 return cnt;
841 int cmd_merge(int argc, const char **argv, const char *prefix)
843 unsigned char result_tree[20];
844 struct strbuf buf = STRBUF_INIT;
845 const char *head_arg;
846 int flag, head_invalid = 0, i;
847 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
848 struct commit_list *common = NULL;
849 const char *best_strategy = NULL, *wt_strategy = NULL;
850 struct commit_list **remotes = &remoteheads;
852 setup_work_tree();
853 if (read_cache_unmerged())
854 die("You are in the middle of a conflicted merge.");
857 * Check if we are _not_ on a detached HEAD, i.e. if there is a
858 * current branch.
860 branch = resolve_ref("HEAD", head, 0, &flag);
861 if (branch && !prefixcmp(branch, "refs/heads/"))
862 branch += 11;
863 if (is_null_sha1(head))
864 head_invalid = 1;
866 git_config(git_merge_config, NULL);
868 /* for color.ui */
869 if (diff_use_color_default == -1)
870 diff_use_color_default = git_use_color_default;
872 argc = parse_options(argc, argv, builtin_merge_options,
873 builtin_merge_usage, 0);
875 if (squash) {
876 if (!allow_fast_forward)
877 die("You cannot combine --squash with --no-ff.");
878 option_commit = 0;
881 if (!argc)
882 usage_with_options(builtin_merge_usage,
883 builtin_merge_options);
886 * This could be traditional "merge <msg> HEAD <commit>..." and
887 * the way we can tell it is to see if the second token is HEAD,
888 * but some people might have misused the interface and used a
889 * committish that is the same as HEAD there instead.
890 * Traditional format never would have "-m" so it is an
891 * additional safety measure to check for it.
894 if (!have_message && is_old_style_invocation(argc, argv)) {
895 strbuf_addstr(&merge_msg, argv[0]);
896 head_arg = argv[1];
897 argv += 2;
898 argc -= 2;
899 } else if (head_invalid) {
900 struct object *remote_head;
902 * If the merged head is a valid one there is no reason
903 * to forbid "git merge" into a branch yet to be born.
904 * We do the same for "git pull".
906 if (argc != 1)
907 die("Can merge only exactly one commit into "
908 "empty head");
909 if (squash)
910 die("Squash commit into empty head not supported yet");
911 if (!allow_fast_forward)
912 die("Non-fast-forward commit does not make sense into "
913 "an empty head");
914 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
915 if (!remote_head)
916 die("%s - not something we can merge", argv[0]);
917 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
918 DIE_ON_ERR);
919 reset_hard(remote_head->sha1, 0);
920 return 0;
921 } else {
922 struct strbuf msg = STRBUF_INIT;
924 /* We are invoked directly as the first-class UI. */
925 head_arg = "HEAD";
928 * All the rest are the commits being merged;
929 * prepare the standard merge summary message to
930 * be appended to the given message. If remote
931 * is invalid we will die later in the common
932 * codepath so we discard the error in this
933 * loop.
935 for (i = 0; i < argc; i++)
936 merge_name(argv[i], &msg);
937 fmt_merge_msg(option_log, &msg, &merge_msg);
938 if (merge_msg.len)
939 strbuf_setlen(&merge_msg, merge_msg.len-1);
942 if (head_invalid || !argc)
943 usage_with_options(builtin_merge_usage,
944 builtin_merge_options);
946 strbuf_addstr(&buf, "merge");
947 for (i = 0; i < argc; i++)
948 strbuf_addf(&buf, " %s", argv[i]);
949 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
950 strbuf_reset(&buf);
952 for (i = 0; i < argc; i++) {
953 struct object *o;
954 struct commit *commit;
956 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
957 if (!o)
958 die("%s - not something we can merge", argv[i]);
959 commit = lookup_commit(o->sha1);
960 commit->util = (void *)argv[i];
961 remotes = &commit_list_insert(commit, remotes)->next;
963 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
964 setenv(buf.buf, argv[i], 1);
965 strbuf_reset(&buf);
968 if (!use_strategies) {
969 if (!remoteheads->next)
970 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
971 else
972 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
975 for (i = 0; i < use_strategies_nr; i++) {
976 if (use_strategies[i]->attr & NO_FAST_FORWARD)
977 allow_fast_forward = 0;
978 if (use_strategies[i]->attr & NO_TRIVIAL)
979 allow_trivial = 0;
982 if (!remoteheads->next)
983 common = get_merge_bases(lookup_commit(head),
984 remoteheads->item, 1);
985 else {
986 struct commit_list *list = remoteheads;
987 commit_list_insert(lookup_commit(head), &list);
988 common = get_octopus_merge_bases(list);
989 free(list);
992 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
993 DIE_ON_ERR);
995 if (!common)
996 ; /* No common ancestors found. We need a real merge. */
997 else if (!remoteheads->next && !common->next &&
998 common->item == remoteheads->item) {
1000 * If head can reach all the merge then we are up to date.
1001 * but first the most common case of merging one remote.
1003 finish_up_to_date("Already up-to-date.");
1004 return 0;
1005 } else if (allow_fast_forward && !remoteheads->next &&
1006 !common->next &&
1007 !hashcmp(common->item->object.sha1, head)) {
1008 /* Again the most common case of merging one remote. */
1009 struct strbuf msg = STRBUF_INIT;
1010 struct object *o;
1011 char hex[41];
1013 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1015 printf("Updating %s..%s\n",
1016 hex,
1017 find_unique_abbrev(remoteheads->item->object.sha1,
1018 DEFAULT_ABBREV));
1019 strbuf_addstr(&msg, "Fast forward");
1020 if (have_message)
1021 strbuf_addstr(&msg,
1022 " (no commit created; -m option ignored)");
1023 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1024 0, NULL, OBJ_COMMIT);
1025 if (!o)
1026 return 1;
1028 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1029 return 1;
1031 finish(o->sha1, msg.buf);
1032 drop_save();
1033 return 0;
1034 } else if (!remoteheads->next && common->next)
1037 * We are not doing octopus and not fast forward. Need
1038 * a real merge.
1040 else if (!remoteheads->next && !common->next && option_commit) {
1042 * We are not doing octopus, not fast forward, and have
1043 * only one common.
1045 refresh_cache(REFRESH_QUIET);
1046 if (allow_trivial) {
1047 /* See if it is really trivial. */
1048 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1049 printf("Trying really trivial in-index merge...\n");
1050 if (!read_tree_trivial(common->item->object.sha1,
1051 head, remoteheads->item->object.sha1))
1052 return merge_trivial();
1053 printf("Nope.\n");
1055 } else {
1057 * An octopus. If we can reach all the remote we are up
1058 * to date.
1060 int up_to_date = 1;
1061 struct commit_list *j;
1063 for (j = remoteheads; j; j = j->next) {
1064 struct commit_list *common_one;
1067 * Here we *have* to calculate the individual
1068 * merge_bases again, otherwise "git merge HEAD^
1069 * HEAD^^" would be missed.
1071 common_one = get_merge_bases(lookup_commit(head),
1072 j->item, 1);
1073 if (hashcmp(common_one->item->object.sha1,
1074 j->item->object.sha1)) {
1075 up_to_date = 0;
1076 break;
1079 if (up_to_date) {
1080 finish_up_to_date("Already up-to-date. Yeeah!");
1081 return 0;
1085 /* We are going to make a new commit. */
1086 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1089 * At this point, we need a real merge. No matter what strategy
1090 * we use, it would operate on the index, possibly affecting the
1091 * working tree, and when resolved cleanly, have the desired
1092 * tree in the index -- this means that the index must be in
1093 * sync with the head commit. The strategies are responsible
1094 * to ensure this.
1096 if (use_strategies_nr != 1) {
1098 * Stash away the local changes so that we can try more
1099 * than one.
1101 save_state();
1102 } else {
1103 memcpy(stash, null_sha1, 20);
1106 for (i = 0; i < use_strategies_nr; i++) {
1107 int ret;
1108 if (i) {
1109 printf("Rewinding the tree to pristine...\n");
1110 restore_state();
1112 if (use_strategies_nr != 1)
1113 printf("Trying merge strategy %s...\n",
1114 use_strategies[i]->name);
1116 * Remember which strategy left the state in the working
1117 * tree.
1119 wt_strategy = use_strategies[i]->name;
1121 ret = try_merge_strategy(use_strategies[i]->name,
1122 common, head_arg);
1123 if (!option_commit && !ret) {
1124 merge_was_ok = 1;
1126 * This is necessary here just to avoid writing
1127 * the tree, but later we will *not* exit with
1128 * status code 1 because merge_was_ok is set.
1130 ret = 1;
1133 if (ret) {
1135 * The backend exits with 1 when conflicts are
1136 * left to be resolved, with 2 when it does not
1137 * handle the given merge at all.
1139 if (ret == 1) {
1140 int cnt = evaluate_result();
1142 if (best_cnt <= 0 || cnt <= best_cnt) {
1143 best_strategy = use_strategies[i]->name;
1144 best_cnt = cnt;
1147 if (merge_was_ok)
1148 break;
1149 else
1150 continue;
1153 /* Automerge succeeded. */
1154 write_tree_trivial(result_tree);
1155 automerge_was_ok = 1;
1156 break;
1160 * If we have a resulting tree, that means the strategy module
1161 * auto resolved the merge cleanly.
1163 if (automerge_was_ok)
1164 return finish_automerge(common, result_tree, wt_strategy);
1167 * Pick the result from the best strategy and have the user fix
1168 * it up.
1170 if (!best_strategy) {
1171 restore_state();
1172 if (use_strategies_nr > 1)
1173 fprintf(stderr,
1174 "No merge strategy handled the merge.\n");
1175 else
1176 fprintf(stderr, "Merge with strategy %s failed.\n",
1177 use_strategies[0]->name);
1178 return 2;
1179 } else if (best_strategy == wt_strategy)
1180 ; /* We already have its result in the working tree. */
1181 else {
1182 printf("Rewinding the tree to pristine...\n");
1183 restore_state();
1184 printf("Using the %s to prepare resolving by hand.\n",
1185 best_strategy);
1186 try_merge_strategy(best_strategy, common, head_arg);
1189 if (squash)
1190 finish(NULL, NULL);
1191 else {
1192 int fd;
1193 struct commit_list *j;
1195 for (j = remoteheads; j; j = j->next)
1196 strbuf_addf(&buf, "%s\n",
1197 sha1_to_hex(j->item->object.sha1));
1198 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1199 if (fd < 0)
1200 die("Could open %s for writing",
1201 git_path("MERGE_HEAD"));
1202 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1203 die("Could not write to %s", git_path("MERGE_HEAD"));
1204 close(fd);
1205 strbuf_addch(&merge_msg, '\n');
1206 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1207 if (fd < 0)
1208 die("Could open %s for writing", git_path("MERGE_MSG"));
1209 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1210 merge_msg.len)
1211 die("Could not write to %s", git_path("MERGE_MSG"));
1212 close(fd);
1215 if (merge_was_ok) {
1216 fprintf(stderr, "Automatic merge went well; "
1217 "stopped before committing as requested\n");
1218 return 0;
1219 } else
1220 return suggest_conflicts();