1 /*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
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;
36 };
38 static const char * const builtin_merge_usage[] = {
39 "git-merge [options] <remote>...",
40 "git-merge [options] <msg> HEAD <remote>",
41 NULL
42 };
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 },
60 };
62 static const char *pull_twohead, *pull_octopus;
64 static int option_parse_message(const struct option *opt,
65 const char *arg, int unset)
66 {
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;
77 }
79 static struct strategy *get_strategy(const char *name)
80 {
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(¬_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(¬_strategies, ent->name, ent->len);
108 exclude_cmds(&main_cmds, ¬_strategies);
109 }
110 }
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");
122 }
123 exit(1);
124 }
126 ret = xmalloc(sizeof(struct strategy));
127 memset(ret, 0, sizeof(struct strategy));
128 ret->name = xstrdup(name);
129 return ret;
130 }
132 static void append_strategy(struct strategy *s)
133 {
134 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
135 use_strategies[use_strategies_nr++] = s;
136 }
138 static int option_parse_strategy(const struct option *opt,
139 const char *name, int unset)
140 {
141 if (unset)
142 return 0;
144 append_strategy(get_strategy(name));
145 return 0;
146 }
148 static int option_parse_n(const struct option *opt,
149 const char *arg, int unset)
150 {
151 show_diffstat = unset;
152 return 0;
153 }
155 static struct option builtin_merge_options[] = {
156 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
157 "do not show a diffstat at the end of the merge",
158 PARSE_OPT_NOARG, option_parse_n },
159 OPT_BOOLEAN(0, "stat", &show_diffstat,
160 "show a diffstat at the end of the merge"),
161 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
162 OPT_BOOLEAN(0, "log", &option_log,
163 "add list of one-line log to merge commit message"),
164 OPT_BOOLEAN(0, "squash", &squash,
165 "create a single commit instead of doing a merge"),
166 OPT_BOOLEAN(0, "commit", &option_commit,
167 "perform a commit if the merge succeeds (default)"),
168 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
169 "allow fast forward (default)"),
170 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
171 "merge strategy to use", option_parse_strategy),
172 OPT_CALLBACK('m', "message", &merge_msg, "message",
173 "message to be used for the merge commit (if any)",
174 option_parse_message),
175 OPT_END()
176 };
178 /* Cleans up metadata that is uninteresting after a succeeded merge. */
179 static void drop_save(void)
180 {
181 unlink(git_path("MERGE_HEAD"));
182 unlink(git_path("MERGE_MSG"));
183 unlink(git_path("MERGE_MODE"));
184 }
186 static void save_state(void)
187 {
188 int len;
189 struct child_process cp;
190 struct strbuf buffer = STRBUF_INIT;
191 const char *argv[] = {"stash", "create", NULL};
193 memset(&cp, 0, sizeof(cp));
194 cp.argv = argv;
195 cp.out = -1;
196 cp.git_cmd = 1;
198 if (start_command(&cp))
199 die("could not run stash.");
200 len = strbuf_read(&buffer, cp.out, 1024);
201 close(cp.out);
203 if (finish_command(&cp) || len < 0)
204 die("stash failed");
205 else if (!len)
206 return;
207 strbuf_setlen(&buffer, buffer.len-1);
208 if (get_sha1(buffer.buf, stash))
209 die("not a valid object: %s", buffer.buf);
210 }
212 static void reset_hard(unsigned const char *sha1, int verbose)
213 {
214 int i = 0;
215 const char *args[6];
217 args[i++] = "read-tree";
218 if (verbose)
219 args[i++] = "-v";
220 args[i++] = "--reset";
221 args[i++] = "-u";
222 args[i++] = sha1_to_hex(sha1);
223 args[i] = NULL;
225 if (run_command_v_opt(args, RUN_GIT_CMD))
226 die("read-tree failed");
227 }
229 static void restore_state(void)
230 {
231 struct strbuf sb;
232 const char *args[] = { "stash", "apply", NULL, NULL };
234 if (is_null_sha1(stash))
235 return;
237 reset_hard(head, 1);
239 strbuf_init(&sb, 0);
240 args[2] = sha1_to_hex(stash);
242 /*
243 * It is OK to ignore error here, for example when there was
244 * nothing to restore.
245 */
246 run_command_v_opt(args, RUN_GIT_CMD);
248 strbuf_release(&sb);
249 refresh_cache(REFRESH_QUIET);
250 }
252 /* This is called when no merge was necessary. */
253 static void finish_up_to_date(const char *msg)
254 {
255 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
256 drop_save();
257 }
259 static void squash_message(void)
260 {
261 struct rev_info rev;
262 struct commit *commit;
263 struct strbuf out;
264 struct commit_list *j;
265 int fd;
267 printf("Squash commit -- not updating HEAD\n");
268 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
269 if (fd < 0)
270 die("Could not write to %s", git_path("SQUASH_MSG"));
272 init_revisions(&rev, NULL);
273 rev.ignore_merges = 1;
274 rev.commit_format = CMIT_FMT_MEDIUM;
276 commit = lookup_commit(head);
277 commit->object.flags |= UNINTERESTING;
278 add_pending_object(&rev, &commit->object, NULL);
280 for (j = remoteheads; j; j = j->next)
281 add_pending_object(&rev, &j->item->object, NULL);
283 setup_revisions(0, NULL, &rev, NULL);
284 if (prepare_revision_walk(&rev))
285 die("revision walk setup failed");
287 strbuf_init(&out, 0);
288 strbuf_addstr(&out, "Squashed commit of the following:\n");
289 while ((commit = get_revision(&rev)) != NULL) {
290 strbuf_addch(&out, '\n');
291 strbuf_addf(&out, "commit %s\n",
292 sha1_to_hex(commit->object.sha1));
293 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
294 NULL, NULL, rev.date_mode, 0);
295 }
296 write(fd, out.buf, out.len);
297 close(fd);
298 strbuf_release(&out);
299 }
301 static int run_hook(const char *name)
302 {
303 struct child_process hook;
304 const char *argv[3], *env[2];
305 char index[PATH_MAX];
307 argv[0] = git_path("hooks/%s", name);
308 if (access(argv[0], X_OK) < 0)
309 return 0;
311 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
312 env[0] = index;
313 env[1] = NULL;
315 if (squash)
316 argv[1] = "1";
317 else
318 argv[1] = "0";
319 argv[2] = NULL;
321 memset(&hook, 0, sizeof(hook));
322 hook.argv = argv;
323 hook.no_stdin = 1;
324 hook.stdout_to_stderr = 1;
325 hook.env = env;
327 return run_command(&hook);
328 }
330 static void finish(const unsigned char *new_head, const char *msg)
331 {
332 struct strbuf reflog_message;
334 strbuf_init(&reflog_message, 0);
335 if (!msg)
336 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
337 else {
338 printf("%s\n", msg);
339 strbuf_addf(&reflog_message, "%s: %s",
340 getenv("GIT_REFLOG_ACTION"), msg);
341 }
342 if (squash) {
343 squash_message();
344 } else {
345 if (!merge_msg.len)
346 printf("No merge message -- not updating HEAD\n");
347 else {
348 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
349 update_ref(reflog_message.buf, "HEAD",
350 new_head, head, 0,
351 DIE_ON_ERR);
352 /*
353 * We ignore errors in 'gc --auto', since the
354 * user should see them.
355 */
356 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
357 }
358 }
359 if (new_head && show_diffstat) {
360 struct diff_options opts;
361 diff_setup(&opts);
362 opts.output_format |=
363 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
364 opts.detect_rename = DIFF_DETECT_RENAME;
365 if (diff_use_color_default > 0)
366 DIFF_OPT_SET(&opts, COLOR_DIFF);
367 if (diff_setup_done(&opts) < 0)
368 die("diff_setup_done failed");
369 diff_tree_sha1(head, new_head, "", &opts);
370 diffcore_std(&opts);
371 diff_flush(&opts);
372 }
374 /* Run a post-merge hook */
375 run_hook("post-merge");
377 strbuf_release(&reflog_message);
378 }
380 /* Get the name for the merge commit's message. */
381 static void merge_name(const char *remote, struct strbuf *msg)
382 {
383 struct object *remote_head;
384 unsigned char branch_head[20], buf_sha[20];
385 struct strbuf buf;
386 const char *ptr;
387 int len, early;
389 memset(branch_head, 0, sizeof(branch_head));
390 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
391 if (!remote_head)
392 die("'%s' does not point to a commit", remote);
394 strbuf_init(&buf, 0);
395 strbuf_addstr(&buf, "refs/heads/");
396 strbuf_addstr(&buf, remote);
397 resolve_ref(buf.buf, branch_head, 0, 0);
399 if (!hashcmp(remote_head->sha1, branch_head)) {
400 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
401 sha1_to_hex(branch_head), remote);
402 return;
403 }
405 /* See if remote matches <name>^^^.. or <name>~<number> */
406 for (len = 0, ptr = remote + strlen(remote);
407 remote < ptr && ptr[-1] == '^';
408 ptr--)
409 len++;
410 if (len)
411 early = 1;
412 else {
413 early = 0;
414 ptr = strrchr(remote, '~');
415 if (ptr) {
416 int seen_nonzero = 0;
418 len++; /* count ~ */
419 while (*++ptr && isdigit(*ptr)) {
420 seen_nonzero |= (*ptr != '0');
421 len++;
422 }
423 if (*ptr)
424 len = 0; /* not ...~<number> */
425 else if (seen_nonzero)
426 early = 1;
427 else if (len == 1)
428 early = 1; /* "name~" is "name~1"! */
429 }
430 }
431 if (len) {
432 struct strbuf truname = STRBUF_INIT;
433 strbuf_addstr(&truname, "refs/heads/");
434 strbuf_addstr(&truname, remote);
435 strbuf_setlen(&truname, truname.len - len);
436 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
437 strbuf_addf(msg,
438 "%s\t\tbranch '%s'%s of .\n",
439 sha1_to_hex(remote_head->sha1),
440 truname.buf + 11,
441 (early ? " (early part)" : ""));
442 return;
443 }
444 }
446 if (!strcmp(remote, "FETCH_HEAD") &&
447 !access(git_path("FETCH_HEAD"), R_OK)) {
448 FILE *fp;
449 struct strbuf line;
450 char *ptr;
452 strbuf_init(&line, 0);
453 fp = fopen(git_path("FETCH_HEAD"), "r");
454 if (!fp)
455 die("could not open %s for reading: %s",
456 git_path("FETCH_HEAD"), strerror(errno));
457 strbuf_getline(&line, fp, '\n');
458 fclose(fp);
459 ptr = strstr(line.buf, "\tnot-for-merge\t");
460 if (ptr)
461 strbuf_remove(&line, ptr-line.buf+1, 13);
462 strbuf_addbuf(msg, &line);
463 strbuf_release(&line);
464 return;
465 }
466 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
467 sha1_to_hex(remote_head->sha1), remote);
468 }
470 static int git_merge_config(const char *k, const char *v, void *cb)
471 {
472 if (branch && !prefixcmp(k, "branch.") &&
473 !prefixcmp(k + 7, branch) &&
474 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
475 const char **argv;
476 int argc;
477 char *buf;
479 buf = xstrdup(v);
480 argc = split_cmdline(buf, &argv);
481 if (argc < 0)
482 die("Bad branch.%s.mergeoptions string", branch);
483 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
484 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
485 argc++;
486 parse_options(argc, argv, builtin_merge_options,
487 builtin_merge_usage, 0);
488 free(buf);
489 }
491 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
492 show_diffstat = git_config_bool(k, v);
493 else if (!strcmp(k, "pull.twohead"))
494 return git_config_string(&pull_twohead, k, v);
495 else if (!strcmp(k, "pull.octopus"))
496 return git_config_string(&pull_octopus, k, v);
497 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
498 option_log = git_config_bool(k, v);
499 return git_diff_ui_config(k, v, cb);
500 }
502 static int read_tree_trivial(unsigned char *common, unsigned char *head,
503 unsigned char *one)
504 {
505 int i, nr_trees = 0;
506 struct tree *trees[MAX_UNPACK_TREES];
507 struct tree_desc t[MAX_UNPACK_TREES];
508 struct unpack_trees_options opts;
510 memset(&opts, 0, sizeof(opts));
511 opts.head_idx = 2;
512 opts.src_index = &the_index;
513 opts.dst_index = &the_index;
514 opts.update = 1;
515 opts.verbose_update = 1;
516 opts.trivial_merges_only = 1;
517 opts.merge = 1;
518 trees[nr_trees] = parse_tree_indirect(common);
519 if (!trees[nr_trees++])
520 return -1;
521 trees[nr_trees] = parse_tree_indirect(head);
522 if (!trees[nr_trees++])
523 return -1;
524 trees[nr_trees] = parse_tree_indirect(one);
525 if (!trees[nr_trees++])
526 return -1;
527 opts.fn = threeway_merge;
528 cache_tree_free(&active_cache_tree);
529 for (i = 0; i < nr_trees; i++) {
530 parse_tree(trees[i]);
531 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
532 }
533 if (unpack_trees(nr_trees, t, &opts))
534 return -1;
535 return 0;
536 }
538 static void write_tree_trivial(unsigned char *sha1)
539 {
540 if (write_cache_as_tree(sha1, 0, NULL))
541 die("git write-tree failed to write a tree");
542 }
544 static int try_merge_strategy(const char *strategy, struct commit_list *common,
545 const char *head_arg)
546 {
547 const char **args;
548 int i = 0, ret;
549 struct commit_list *j;
550 struct strbuf buf;
552 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
553 int clean;
554 struct commit *result;
555 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
556 int index_fd;
557 struct commit_list *reversed = NULL;
558 struct merge_options o;
560 if (remoteheads->next) {
561 error("Not handling anything other than two heads merge.");
562 return 2;
563 }
565 init_merge_options(&o);
566 if (!strcmp(strategy, "subtree"))
567 o.subtree_merge = 1;
569 o.branch1 = head_arg;
570 o.branch2 = remoteheads->item->util;
572 for (j = common; j; j = j->next)
573 commit_list_insert(j->item, &reversed);
575 index_fd = hold_locked_index(lock, 1);
576 clean = merge_recursive(&o, lookup_commit(head),
577 remoteheads->item, reversed, &result);
578 if (active_cache_changed &&
579 (write_cache(index_fd, active_cache, active_nr) ||
580 commit_locked_index(lock)))
581 die ("unable to write %s", get_index_file());
582 rollback_lock_file(lock);
583 return clean ? 0 : 1;
584 } else {
585 args = xmalloc((4 + commit_list_count(common) +
586 commit_list_count(remoteheads)) * sizeof(char *));
587 strbuf_init(&buf, 0);
588 strbuf_addf(&buf, "merge-%s", strategy);
589 args[i++] = buf.buf;
590 for (j = common; j; j = j->next)
591 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
592 args[i++] = "--";
593 args[i++] = head_arg;
594 for (j = remoteheads; j; j = j->next)
595 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
596 args[i] = NULL;
597 ret = run_command_v_opt(args, RUN_GIT_CMD);
598 strbuf_release(&buf);
599 i = 1;
600 for (j = common; j; j = j->next)
601 free((void *)args[i++]);
602 i += 2;
603 for (j = remoteheads; j; j = j->next)
604 free((void *)args[i++]);
605 free(args);
606 discard_cache();
607 if (read_cache() < 0)
608 die("failed to read the cache");
609 return -ret;
610 }
611 }
613 static void count_diff_files(struct diff_queue_struct *q,
614 struct diff_options *opt, void *data)
615 {
616 int *count = data;
618 (*count) += q->nr;
619 }
621 static int count_unmerged_entries(void)
622 {
623 const struct index_state *state = &the_index;
624 int i, ret = 0;
626 for (i = 0; i < state->cache_nr; i++)
627 if (ce_stage(state->cache[i]))
628 ret++;
630 return ret;
631 }
633 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
634 {
635 struct tree *trees[MAX_UNPACK_TREES];
636 struct unpack_trees_options opts;
637 struct tree_desc t[MAX_UNPACK_TREES];
638 int i, fd, nr_trees = 0;
639 struct dir_struct dir;
640 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
642 refresh_cache(REFRESH_QUIET);
644 fd = hold_locked_index(lock_file, 1);
646 memset(&trees, 0, sizeof(trees));
647 memset(&opts, 0, sizeof(opts));
648 memset(&t, 0, sizeof(t));
649 memset(&dir, 0, sizeof(dir));
650 dir.show_ignored = 1;
651 dir.exclude_per_dir = ".gitignore";
652 opts.dir = &dir;
654 opts.head_idx = 1;
655 opts.src_index = &the_index;
656 opts.dst_index = &the_index;
657 opts.update = 1;
658 opts.verbose_update = 1;
659 opts.merge = 1;
660 opts.fn = twoway_merge;
662 trees[nr_trees] = parse_tree_indirect(head);
663 if (!trees[nr_trees++])
664 return -1;
665 trees[nr_trees] = parse_tree_indirect(remote);
666 if (!trees[nr_trees++])
667 return -1;
668 for (i = 0; i < nr_trees; i++) {
669 parse_tree(trees[i]);
670 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
671 }
672 if (unpack_trees(nr_trees, t, &opts))
673 return -1;
674 if (write_cache(fd, active_cache, active_nr) ||
675 commit_locked_index(lock_file))
676 die("unable to write new index file");
677 return 0;
678 }
680 static void split_merge_strategies(const char *string, struct strategy **list,
681 int *nr, int *alloc)
682 {
683 char *p, *q, *buf;
685 if (!string)
686 return;
688 buf = xstrdup(string);
689 q = buf;
690 for (;;) {
691 p = strchr(q, ' ');
692 if (!p) {
693 ALLOC_GROW(*list, *nr + 1, *alloc);
694 (*list)[(*nr)++].name = xstrdup(q);
695 free(buf);
696 return;
697 } else {
698 *p = '\0';
699 ALLOC_GROW(*list, *nr + 1, *alloc);
700 (*list)[(*nr)++].name = xstrdup(q);
701 q = ++p;
702 }
703 }
704 }
706 static void add_strategies(const char *string, unsigned attr)
707 {
708 struct strategy *list = NULL;
709 int list_alloc = 0, list_nr = 0, i;
711 memset(&list, 0, sizeof(list));
712 split_merge_strategies(string, &list, &list_nr, &list_alloc);
713 if (list) {
714 for (i = 0; i < list_nr; i++)
715 append_strategy(get_strategy(list[i].name));
716 return;
717 }
718 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
719 if (all_strategy[i].attr & attr)
720 append_strategy(&all_strategy[i]);
722 }
724 static int merge_trivial(void)
725 {
726 unsigned char result_tree[20], result_commit[20];
727 struct commit_list *parent = xmalloc(sizeof(struct commit_list *));
729 write_tree_trivial(result_tree);
730 printf("Wonderful.\n");
731 parent->item = lookup_commit(head);
732 parent->next = xmalloc(sizeof(struct commit_list *));
733 parent->next->item = remoteheads->item;
734 parent->next->next = NULL;
735 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
736 finish(result_commit, "In-index merge");
737 drop_save();
738 return 0;
739 }
741 static int finish_automerge(struct commit_list *common,
742 unsigned char *result_tree,
743 const char *wt_strategy)
744 {
745 struct commit_list *parents = NULL, *j;
746 struct strbuf buf = STRBUF_INIT;
747 unsigned char result_commit[20];
749 free_commit_list(common);
750 if (allow_fast_forward) {
751 parents = remoteheads;
752 commit_list_insert(lookup_commit(head), &parents);
753 parents = reduce_heads(parents);
754 } else {
755 struct commit_list **pptr = &parents;
757 pptr = &commit_list_insert(lookup_commit(head),
758 pptr)->next;
759 for (j = remoteheads; j; j = j->next)
760 pptr = &commit_list_insert(j->item, pptr)->next;
761 }
762 free_commit_list(remoteheads);
763 strbuf_addch(&merge_msg, '\n');
764 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
765 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
766 finish(result_commit, buf.buf);
767 strbuf_release(&buf);
768 drop_save();
769 return 0;
770 }
772 static int suggest_conflicts(void)
773 {
774 FILE *fp;
775 int pos;
777 fp = fopen(git_path("MERGE_MSG"), "a");
778 if (!fp)
779 die("Could open %s for writing", git_path("MERGE_MSG"));
780 fprintf(fp, "\nConflicts:\n");
781 for (pos = 0; pos < active_nr; pos++) {
782 struct cache_entry *ce = active_cache[pos];
784 if (ce_stage(ce)) {
785 fprintf(fp, "\t%s\n", ce->name);
786 while (pos + 1 < active_nr &&
787 !strcmp(ce->name,
788 active_cache[pos + 1]->name))
789 pos++;
790 }
791 }
792 fclose(fp);
793 rerere();
794 printf("Automatic merge failed; "
795 "fix conflicts and then commit the result.\n");
796 return 1;
797 }
799 static struct commit *is_old_style_invocation(int argc, const char **argv)
800 {
801 struct commit *second_token = NULL;
802 if (argc > 1) {
803 unsigned char second_sha1[20];
805 if (get_sha1(argv[1], second_sha1))
806 return NULL;
807 second_token = lookup_commit_reference_gently(second_sha1, 0);
808 if (!second_token)
809 die("'%s' is not a commit", argv[1]);
810 if (hashcmp(second_token->object.sha1, head))
811 return NULL;
812 }
813 return second_token;
814 }
816 static int evaluate_result(void)
817 {
818 int cnt = 0;
819 struct rev_info rev;
821 /* Check how many files differ. */
822 init_revisions(&rev, "");
823 setup_revisions(0, NULL, &rev, NULL);
824 rev.diffopt.output_format |=
825 DIFF_FORMAT_CALLBACK;
826 rev.diffopt.format_callback = count_diff_files;
827 rev.diffopt.format_callback_data = &cnt;
828 run_diff_files(&rev, 0);
830 /*
831 * Check how many unmerged entries are
832 * there.
833 */
834 cnt += count_unmerged_entries();
836 return cnt;
837 }
839 int cmd_merge(int argc, const char **argv, const char *prefix)
840 {
841 unsigned char result_tree[20];
842 struct strbuf buf;
843 const char *head_arg;
844 int flag, head_invalid = 0, i;
845 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
846 struct commit_list *common = NULL;
847 const char *best_strategy = NULL, *wt_strategy = NULL;
848 struct commit_list **remotes = &remoteheads;
850 setup_work_tree();
851 if (read_cache_unmerged())
852 die("You are in the middle of a conflicted merge.");
854 /*
855 * Check if we are _not_ on a detached HEAD, i.e. if there is a
856 * current branch.
857 */
858 branch = resolve_ref("HEAD", head, 0, &flag);
859 if (branch && !prefixcmp(branch, "refs/heads/"))
860 branch += 11;
861 if (is_null_sha1(head))
862 head_invalid = 1;
864 git_config(git_merge_config, NULL);
866 /* for color.ui */
867 if (diff_use_color_default == -1)
868 diff_use_color_default = git_use_color_default;
870 argc = parse_options(argc, argv, builtin_merge_options,
871 builtin_merge_usage, 0);
873 if (squash) {
874 if (!allow_fast_forward)
875 die("You cannot combine --squash with --no-ff.");
876 option_commit = 0;
877 }
879 if (!argc)
880 usage_with_options(builtin_merge_usage,
881 builtin_merge_options);
883 /*
884 * This could be traditional "merge <msg> HEAD <commit>..." and
885 * the way we can tell it is to see if the second token is HEAD,
886 * but some people might have misused the interface and used a
887 * committish that is the same as HEAD there instead.
888 * Traditional format never would have "-m" so it is an
889 * additional safety measure to check for it.
890 */
891 strbuf_init(&buf, 0);
893 if (!have_message && is_old_style_invocation(argc, argv)) {
894 strbuf_addstr(&merge_msg, argv[0]);
895 head_arg = argv[1];
896 argv += 2;
897 argc -= 2;
898 } else if (head_invalid) {
899 struct object *remote_head;
900 /*
901 * If the merged head is a valid one there is no reason
902 * to forbid "git merge" into a branch yet to be born.
903 * We do the same for "git pull".
904 */
905 if (argc != 1)
906 die("Can merge only exactly one commit into "
907 "empty head");
908 if (squash)
909 die("Squash commit into empty head not supported yet");
910 if (!allow_fast_forward)
911 die("Non-fast-forward commit does not make sense into "
912 "an empty head");
913 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
914 if (!remote_head)
915 die("%s - not something we can merge", argv[0]);
916 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
917 DIE_ON_ERR);
918 reset_hard(remote_head->sha1, 0);
919 return 0;
920 } else {
921 struct strbuf msg;
923 /* We are invoked directly as the first-class UI. */
924 head_arg = "HEAD";
926 /*
927 * All the rest are the commits being merged;
928 * prepare the standard merge summary message to
929 * be appended to the given message. If remote
930 * is invalid we will die later in the common
931 * codepath so we discard the error in this
932 * loop.
933 */
934 strbuf_init(&msg, 0);
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);
940 }
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);
966 }
968 if (!use_strategies) {
969 if (!remoteheads->next)
970 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
971 else
972 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
973 }
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;
980 }
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);
990 }
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) {
999 /*
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.
1002 */
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;
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_init(&msg, 0);
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)
1036 ;
1037 /*
1038 * We are not doing octopus and not fast forward. Need
1039 * a real merge.
1040 */
1041 else if (!remoteheads->next && !common->next && option_commit) {
1042 /*
1043 * We are not doing octopus, not fast forward, and have
1044 * only one common.
1045 */
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");
1055 }
1056 } else {
1057 /*
1058 * An octopus. If we can reach all the remote we are up
1059 * to date.
1060 */
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;
1067 /*
1068 * Here we *have* to calculate the individual
1069 * merge_bases again, otherwise "git merge HEAD^
1070 * HEAD^^" would be missed.
1071 */
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;
1078 }
1079 }
1080 if (up_to_date) {
1081 finish_up_to_date("Already up-to-date. Yeeah!");
1082 return 0;
1083 }
1084 }
1086 /* We are going to make a new commit. */
1087 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1089 /*
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.
1096 */
1097 if (use_strategies_nr != 1) {
1098 /*
1099 * Stash away the local changes so that we can try more
1100 * than one.
1101 */
1102 save_state();
1103 } else {
1104 memcpy(stash, null_sha1, 20);
1105 }
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();
1112 }
1113 if (use_strategies_nr != 1)
1114 printf("Trying merge strategy %s...\n",
1115 use_strategies[i]->name);
1116 /*
1117 * Remember which strategy left the state in the working
1118 * tree.
1119 */
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;
1126 /*
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.
1130 */
1131 ret = 1;
1132 }
1134 if (ret) {
1135 /*
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.
1139 */
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;
1146 }
1147 }
1148 if (merge_was_ok)
1149 break;
1150 else
1151 continue;
1152 }
1154 /* Automerge succeeded. */
1155 write_tree_trivial(result_tree);
1156 automerge_was_ok = 1;
1157 break;
1158 }
1160 /*
1161 * If we have a resulting tree, that means the strategy module
1162 * auto resolved the merge cleanly.
1163 */
1164 if (automerge_was_ok)
1165 return finish_automerge(common, result_tree, wt_strategy);
1167 /*
1168 * Pick the result from the best strategy and have the user fix
1169 * it up.
1170 */
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);
1188 }
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);
1223 }
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();
1231 }