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[git/platforms.git] / builtin-merge.c
blob885fad9bba1310e6ed8424f9d4b481e066760a9b
1 /*
2 * Builtin "git merge"
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
6 * Based on git-merge.sh by Junio C Hamano.
7 */
9 #include "cache.h"
10 #include "parse-options.h"
11 #include "builtin.h"
12 #include "run-command.h"
13 #include "diff.h"
14 #include "refs.h"
15 #include "commit.h"
16 #include "diffcore.h"
17 #include "revision.h"
18 #include "unpack-trees.h"
19 #include "cache-tree.h"
20 #include "dir.h"
21 #include "utf8.h"
22 #include "log-tree.h"
23 #include "color.h"
24 #include "rerere.h"
25 #include "help.h"
26 #include "merge-recursive.h"
28 #define DEFAULT_TWOHEAD (1<<0)
29 #define DEFAULT_OCTOPUS (1<<1)
30 #define NO_FAST_FORWARD (1<<2)
31 #define NO_TRIVIAL (1<<3)
33 struct strategy {
34 const char *name;
35 unsigned attr;
38 static const char * const builtin_merge_usage[] = {
39 "git merge [options] <remote>...",
40 "git merge [options] <msg> HEAD <remote>",
41 NULL
44 static int show_diffstat = 1, option_log, squash;
45 static int option_commit = 1, allow_fast_forward = 1;
46 static int allow_trivial = 1, have_message;
47 static struct strbuf merge_msg;
48 static struct commit_list *remoteheads;
49 static unsigned char head[20], stash[20];
50 static struct strategy **use_strategies;
51 static size_t use_strategies_nr, use_strategies_alloc;
52 static const char *branch;
53 static int verbosity;
55 static struct strategy all_strategy[] = {
56 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
57 { "octopus", DEFAULT_OCTOPUS },
58 { "resolve", 0 },
59 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
60 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
63 static const char *pull_twohead, *pull_octopus;
65 static int option_parse_message(const struct option *opt,
66 const char *arg, int unset)
68 struct strbuf *buf = opt->value;
70 if (unset)
71 strbuf_setlen(buf, 0);
72 else if (arg) {
73 strbuf_addf(buf, "%s\n\n", arg);
74 have_message = 1;
75 } else
76 return error("switch `m' requires a value");
77 return 0;
80 static struct strategy *get_strategy(const char *name)
82 int i;
83 struct strategy *ret;
84 static struct cmdnames main_cmds, other_cmds;
85 static int loaded;
87 if (!name)
88 return NULL;
90 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
91 if (!strcmp(name, all_strategy[i].name))
92 return &all_strategy[i];
94 if (!loaded) {
95 struct cmdnames not_strategies;
96 loaded = 1;
98 memset(&not_strategies, 0, sizeof(struct cmdnames));
99 load_command_list("git-merge-", &main_cmds, &other_cmds);
100 for (i = 0; i < main_cmds.cnt; i++) {
101 int j, found = 0;
102 struct cmdname *ent = main_cmds.names[i];
103 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
104 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
105 && !all_strategy[j].name[ent->len])
106 found = 1;
107 if (!found)
108 add_cmdname(&not_strategies, ent->name, ent->len);
109 exclude_cmds(&main_cmds, &not_strategies);
112 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
113 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
114 fprintf(stderr, "Available strategies are:");
115 for (i = 0; i < main_cmds.cnt; i++)
116 fprintf(stderr, " %s", main_cmds.names[i]->name);
117 fprintf(stderr, ".\n");
118 if (other_cmds.cnt) {
119 fprintf(stderr, "Available custom strategies are:");
120 for (i = 0; i < other_cmds.cnt; i++)
121 fprintf(stderr, " %s", other_cmds.names[i]->name);
122 fprintf(stderr, ".\n");
124 exit(1);
127 ret = xcalloc(1, sizeof(struct strategy));
128 ret->name = xstrdup(name);
129 return ret;
132 static void append_strategy(struct strategy *s)
134 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
135 use_strategies[use_strategies_nr++] = s;
138 static int option_parse_strategy(const struct option *opt,
139 const char *name, int unset)
141 if (unset)
142 return 0;
144 append_strategy(get_strategy(name));
145 return 0;
148 static int option_parse_n(const struct option *opt,
149 const char *arg, int unset)
151 show_diffstat = unset;
152 return 0;
155 static struct option builtin_merge_options[] = {
156 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
157 "do not show a diffstat at the end of the merge",
158 PARSE_OPT_NOARG, option_parse_n },
159 OPT_BOOLEAN(0, "stat", &show_diffstat,
160 "show a diffstat at the end of the merge"),
161 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
162 OPT_BOOLEAN(0, "log", &option_log,
163 "add list of one-line log to merge commit message"),
164 OPT_BOOLEAN(0, "squash", &squash,
165 "create a single commit instead of doing a merge"),
166 OPT_BOOLEAN(0, "commit", &option_commit,
167 "perform a commit if the merge succeeds (default)"),
168 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
169 "allow fast forward (default)"),
170 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
171 "merge strategy to use", option_parse_strategy),
172 OPT_CALLBACK('m', "message", &merge_msg, "message",
173 "message to be used for the merge commit (if any)",
174 option_parse_message),
175 OPT__VERBOSITY(&verbosity),
176 OPT_END()
179 /* Cleans up metadata that is uninteresting after a succeeded merge. */
180 static void drop_save(void)
182 unlink(git_path("MERGE_HEAD"));
183 unlink(git_path("MERGE_MSG"));
184 unlink(git_path("MERGE_MODE"));
187 static void save_state(void)
189 int len;
190 struct child_process cp;
191 struct strbuf buffer = STRBUF_INIT;
192 const char *argv[] = {"stash", "create", NULL};
194 memset(&cp, 0, sizeof(cp));
195 cp.argv = argv;
196 cp.out = -1;
197 cp.git_cmd = 1;
199 if (start_command(&cp))
200 die("could not run stash.");
201 len = strbuf_read(&buffer, cp.out, 1024);
202 close(cp.out);
204 if (finish_command(&cp) || len < 0)
205 die("stash failed");
206 else if (!len)
207 return;
208 strbuf_setlen(&buffer, buffer.len-1);
209 if (get_sha1(buffer.buf, stash))
210 die("not a valid object: %s", buffer.buf);
213 static void reset_hard(unsigned const char *sha1, int verbose)
215 int i = 0;
216 const char *args[6];
218 args[i++] = "read-tree";
219 if (verbose)
220 args[i++] = "-v";
221 args[i++] = "--reset";
222 args[i++] = "-u";
223 args[i++] = sha1_to_hex(sha1);
224 args[i] = NULL;
226 if (run_command_v_opt(args, RUN_GIT_CMD))
227 die("read-tree failed");
230 static void restore_state(void)
232 struct strbuf sb = STRBUF_INIT;
233 const char *args[] = { "stash", "apply", NULL, NULL };
235 if (is_null_sha1(stash))
236 return;
238 reset_hard(head, 1);
240 args[2] = sha1_to_hex(stash);
243 * It is OK to ignore error here, for example when there was
244 * nothing to restore.
246 run_command_v_opt(args, RUN_GIT_CMD);
248 strbuf_release(&sb);
249 refresh_cache(REFRESH_QUIET);
252 /* This is called when no merge was necessary. */
253 static void finish_up_to_date(const char *msg)
255 if (verbosity >= 0)
256 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
257 drop_save();
260 static void squash_message(void)
262 struct rev_info rev;
263 struct commit *commit;
264 struct strbuf out = STRBUF_INIT;
265 struct commit_list *j;
266 int fd;
268 printf("Squash commit -- not updating HEAD\n");
269 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
270 if (fd < 0)
271 die("Could not write to %s", git_path("SQUASH_MSG"));
273 init_revisions(&rev, NULL);
274 rev.ignore_merges = 1;
275 rev.commit_format = CMIT_FMT_MEDIUM;
277 commit = lookup_commit(head);
278 commit->object.flags |= UNINTERESTING;
279 add_pending_object(&rev, &commit->object, NULL);
281 for (j = remoteheads; j; j = j->next)
282 add_pending_object(&rev, &j->item->object, NULL);
284 setup_revisions(0, NULL, &rev, NULL);
285 if (prepare_revision_walk(&rev))
286 die("revision walk setup failed");
288 strbuf_addstr(&out, "Squashed commit of the following:\n");
289 while ((commit = get_revision(&rev)) != NULL) {
290 strbuf_addch(&out, '\n');
291 strbuf_addf(&out, "commit %s\n",
292 sha1_to_hex(commit->object.sha1));
293 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
294 NULL, NULL, rev.date_mode, 0);
296 if (write(fd, out.buf, out.len) < 0)
297 die("Writing SQUASH_MSG: %s", strerror(errno));
298 if (close(fd))
299 die("Finishing SQUASH_MSG: %s", strerror(errno));
300 strbuf_release(&out);
303 static void finish(const unsigned char *new_head, const char *msg)
305 struct strbuf reflog_message = STRBUF_INIT;
307 if (!msg)
308 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
309 else {
310 if (verbosity >= 0)
311 printf("%s\n", msg);
312 strbuf_addf(&reflog_message, "%s: %s",
313 getenv("GIT_REFLOG_ACTION"), msg);
315 if (squash) {
316 squash_message();
317 } else {
318 if (verbosity >= 0 && !merge_msg.len)
319 printf("No merge message -- not updating HEAD\n");
320 else {
321 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
322 update_ref(reflog_message.buf, "HEAD",
323 new_head, head, 0,
324 DIE_ON_ERR);
326 * We ignore errors in 'gc --auto', since the
327 * user should see them.
329 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
332 if (new_head && show_diffstat) {
333 struct diff_options opts;
334 diff_setup(&opts);
335 opts.output_format |=
336 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
337 opts.detect_rename = DIFF_DETECT_RENAME;
338 if (diff_use_color_default > 0)
339 DIFF_OPT_SET(&opts, COLOR_DIFF);
340 if (diff_setup_done(&opts) < 0)
341 die("diff_setup_done failed");
342 diff_tree_sha1(head, new_head, "", &opts);
343 diffcore_std(&opts);
344 diff_flush(&opts);
347 /* Run a post-merge hook */
348 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
350 strbuf_release(&reflog_message);
353 /* Get the name for the merge commit's message. */
354 static void merge_name(const char *remote, struct strbuf *msg)
356 struct object *remote_head;
357 unsigned char branch_head[20], buf_sha[20];
358 struct strbuf buf = STRBUF_INIT;
359 const char *ptr;
360 int len, early;
362 memset(branch_head, 0, sizeof(branch_head));
363 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
364 if (!remote_head)
365 die("'%s' does not point to a commit", remote);
367 strbuf_addstr(&buf, "refs/heads/");
368 strbuf_addstr(&buf, remote);
369 resolve_ref(buf.buf, branch_head, 0, 0);
371 if (!hashcmp(remote_head->sha1, branch_head)) {
372 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
373 sha1_to_hex(branch_head), remote);
374 return;
377 /* See if remote matches <name>^^^.. or <name>~<number> */
378 for (len = 0, ptr = remote + strlen(remote);
379 remote < ptr && ptr[-1] == '^';
380 ptr--)
381 len++;
382 if (len)
383 early = 1;
384 else {
385 early = 0;
386 ptr = strrchr(remote, '~');
387 if (ptr) {
388 int seen_nonzero = 0;
390 len++; /* count ~ */
391 while (*++ptr && isdigit(*ptr)) {
392 seen_nonzero |= (*ptr != '0');
393 len++;
395 if (*ptr)
396 len = 0; /* not ...~<number> */
397 else if (seen_nonzero)
398 early = 1;
399 else if (len == 1)
400 early = 1; /* "name~" is "name~1"! */
403 if (len) {
404 struct strbuf truname = STRBUF_INIT;
405 strbuf_addstr(&truname, "refs/heads/");
406 strbuf_addstr(&truname, remote);
407 strbuf_setlen(&truname, truname.len - len);
408 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
409 strbuf_addf(msg,
410 "%s\t\tbranch '%s'%s of .\n",
411 sha1_to_hex(remote_head->sha1),
412 truname.buf + 11,
413 (early ? " (early part)" : ""));
414 return;
418 if (!strcmp(remote, "FETCH_HEAD") &&
419 !access(git_path("FETCH_HEAD"), R_OK)) {
420 FILE *fp;
421 struct strbuf line = STRBUF_INIT;
422 char *ptr;
424 fp = fopen(git_path("FETCH_HEAD"), "r");
425 if (!fp)
426 die("could not open %s for reading: %s",
427 git_path("FETCH_HEAD"), strerror(errno));
428 strbuf_getline(&line, fp, '\n');
429 fclose(fp);
430 ptr = strstr(line.buf, "\tnot-for-merge\t");
431 if (ptr)
432 strbuf_remove(&line, ptr-line.buf+1, 13);
433 strbuf_addbuf(msg, &line);
434 strbuf_release(&line);
435 return;
437 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
438 sha1_to_hex(remote_head->sha1), remote);
441 static int git_merge_config(const char *k, const char *v, void *cb)
443 if (branch && !prefixcmp(k, "branch.") &&
444 !prefixcmp(k + 7, branch) &&
445 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
446 const char **argv;
447 int argc;
448 char *buf;
450 buf = xstrdup(v);
451 argc = split_cmdline(buf, &argv);
452 if (argc < 0)
453 die("Bad branch.%s.mergeoptions string", branch);
454 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
455 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
456 argc++;
457 parse_options(argc, argv, builtin_merge_options,
458 builtin_merge_usage, 0);
459 free(buf);
462 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
463 show_diffstat = git_config_bool(k, v);
464 else if (!strcmp(k, "pull.twohead"))
465 return git_config_string(&pull_twohead, k, v);
466 else if (!strcmp(k, "pull.octopus"))
467 return git_config_string(&pull_octopus, k, v);
468 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
469 option_log = git_config_bool(k, v);
470 return git_diff_ui_config(k, v, cb);
473 static int read_tree_trivial(unsigned char *common, unsigned char *head,
474 unsigned char *one)
476 int i, nr_trees = 0;
477 struct tree *trees[MAX_UNPACK_TREES];
478 struct tree_desc t[MAX_UNPACK_TREES];
479 struct unpack_trees_options opts;
481 memset(&opts, 0, sizeof(opts));
482 opts.head_idx = 2;
483 opts.src_index = &the_index;
484 opts.dst_index = &the_index;
485 opts.update = 1;
486 opts.verbose_update = 1;
487 opts.trivial_merges_only = 1;
488 opts.merge = 1;
489 trees[nr_trees] = parse_tree_indirect(common);
490 if (!trees[nr_trees++])
491 return -1;
492 trees[nr_trees] = parse_tree_indirect(head);
493 if (!trees[nr_trees++])
494 return -1;
495 trees[nr_trees] = parse_tree_indirect(one);
496 if (!trees[nr_trees++])
497 return -1;
498 opts.fn = threeway_merge;
499 cache_tree_free(&active_cache_tree);
500 for (i = 0; i < nr_trees; i++) {
501 parse_tree(trees[i]);
502 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
504 if (unpack_trees(nr_trees, t, &opts))
505 return -1;
506 return 0;
509 static void write_tree_trivial(unsigned char *sha1)
511 if (write_cache_as_tree(sha1, 0, NULL))
512 die("git write-tree failed to write a tree");
515 static int try_merge_strategy(const char *strategy, struct commit_list *common,
516 const char *head_arg)
518 const char **args;
519 int i = 0, ret;
520 struct commit_list *j;
521 struct strbuf buf = STRBUF_INIT;
522 int index_fd;
523 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
525 index_fd = hold_locked_index(lock, 1);
526 refresh_cache(REFRESH_QUIET);
527 if (active_cache_changed &&
528 (write_cache(index_fd, active_cache, active_nr) ||
529 commit_locked_index(lock)))
530 return error("Unable to write index.");
531 rollback_lock_file(lock);
533 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
534 int clean;
535 struct commit *result;
536 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
537 int index_fd;
538 struct commit_list *reversed = NULL;
539 struct merge_options o;
541 if (remoteheads->next) {
542 error("Not handling anything other than two heads merge.");
543 return 2;
546 init_merge_options(&o);
547 if (!strcmp(strategy, "subtree"))
548 o.subtree_merge = 1;
550 o.branch1 = head_arg;
551 o.branch2 = remoteheads->item->util;
553 for (j = common; j; j = j->next)
554 commit_list_insert(j->item, &reversed);
556 index_fd = hold_locked_index(lock, 1);
557 clean = merge_recursive(&o, lookup_commit(head),
558 remoteheads->item, reversed, &result);
559 if (active_cache_changed &&
560 (write_cache(index_fd, active_cache, active_nr) ||
561 commit_locked_index(lock)))
562 die ("unable to write %s", get_index_file());
563 rollback_lock_file(lock);
564 return clean ? 0 : 1;
565 } else {
566 args = xmalloc((4 + commit_list_count(common) +
567 commit_list_count(remoteheads)) * sizeof(char *));
568 strbuf_addf(&buf, "merge-%s", strategy);
569 args[i++] = buf.buf;
570 for (j = common; j; j = j->next)
571 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
572 args[i++] = "--";
573 args[i++] = head_arg;
574 for (j = remoteheads; j; j = j->next)
575 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
576 args[i] = NULL;
577 ret = run_command_v_opt(args, RUN_GIT_CMD);
578 strbuf_release(&buf);
579 i = 1;
580 for (j = common; j; j = j->next)
581 free((void *)args[i++]);
582 i += 2;
583 for (j = remoteheads; j; j = j->next)
584 free((void *)args[i++]);
585 free(args);
586 discard_cache();
587 if (read_cache() < 0)
588 die("failed to read the cache");
589 return -ret;
593 static void count_diff_files(struct diff_queue_struct *q,
594 struct diff_options *opt, void *data)
596 int *count = data;
598 (*count) += q->nr;
601 static int count_unmerged_entries(void)
603 const struct index_state *state = &the_index;
604 int i, ret = 0;
606 for (i = 0; i < state->cache_nr; i++)
607 if (ce_stage(state->cache[i]))
608 ret++;
610 return ret;
613 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
615 struct tree *trees[MAX_UNPACK_TREES];
616 struct unpack_trees_options opts;
617 struct tree_desc t[MAX_UNPACK_TREES];
618 int i, fd, nr_trees = 0;
619 struct dir_struct dir;
620 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
622 refresh_cache(REFRESH_QUIET);
624 fd = hold_locked_index(lock_file, 1);
626 memset(&trees, 0, sizeof(trees));
627 memset(&opts, 0, sizeof(opts));
628 memset(&t, 0, sizeof(t));
629 memset(&dir, 0, sizeof(dir));
630 dir.show_ignored = 1;
631 dir.exclude_per_dir = ".gitignore";
632 opts.dir = &dir;
634 opts.head_idx = 1;
635 opts.src_index = &the_index;
636 opts.dst_index = &the_index;
637 opts.update = 1;
638 opts.verbose_update = 1;
639 opts.merge = 1;
640 opts.fn = twoway_merge;
642 trees[nr_trees] = parse_tree_indirect(head);
643 if (!trees[nr_trees++])
644 return -1;
645 trees[nr_trees] = parse_tree_indirect(remote);
646 if (!trees[nr_trees++])
647 return -1;
648 for (i = 0; i < nr_trees; i++) {
649 parse_tree(trees[i]);
650 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
652 if (unpack_trees(nr_trees, t, &opts))
653 return -1;
654 if (write_cache(fd, active_cache, active_nr) ||
655 commit_locked_index(lock_file))
656 die("unable to write new index file");
657 return 0;
660 static void split_merge_strategies(const char *string, struct strategy **list,
661 int *nr, int *alloc)
663 char *p, *q, *buf;
665 if (!string)
666 return;
668 buf = xstrdup(string);
669 q = buf;
670 for (;;) {
671 p = strchr(q, ' ');
672 if (!p) {
673 ALLOC_GROW(*list, *nr + 1, *alloc);
674 (*list)[(*nr)++].name = xstrdup(q);
675 free(buf);
676 return;
677 } else {
678 *p = '\0';
679 ALLOC_GROW(*list, *nr + 1, *alloc);
680 (*list)[(*nr)++].name = xstrdup(q);
681 q = ++p;
686 static void add_strategies(const char *string, unsigned attr)
688 struct strategy *list = NULL;
689 int list_alloc = 0, list_nr = 0, i;
691 memset(&list, 0, sizeof(list));
692 split_merge_strategies(string, &list, &list_nr, &list_alloc);
693 if (list) {
694 for (i = 0; i < list_nr; i++)
695 append_strategy(get_strategy(list[i].name));
696 return;
698 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
699 if (all_strategy[i].attr & attr)
700 append_strategy(&all_strategy[i]);
704 static int merge_trivial(void)
706 unsigned char result_tree[20], result_commit[20];
707 struct commit_list *parent = xmalloc(sizeof(*parent));
709 write_tree_trivial(result_tree);
710 printf("Wonderful.\n");
711 parent->item = lookup_commit(head);
712 parent->next = xmalloc(sizeof(*parent->next));
713 parent->next->item = remoteheads->item;
714 parent->next->next = NULL;
715 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
716 finish(result_commit, "In-index merge");
717 drop_save();
718 return 0;
721 static int finish_automerge(struct commit_list *common,
722 unsigned char *result_tree,
723 const char *wt_strategy)
725 struct commit_list *parents = NULL, *j;
726 struct strbuf buf = STRBUF_INIT;
727 unsigned char result_commit[20];
729 free_commit_list(common);
730 if (allow_fast_forward) {
731 parents = remoteheads;
732 commit_list_insert(lookup_commit(head), &parents);
733 parents = reduce_heads(parents);
734 } else {
735 struct commit_list **pptr = &parents;
737 pptr = &commit_list_insert(lookup_commit(head),
738 pptr)->next;
739 for (j = remoteheads; j; j = j->next)
740 pptr = &commit_list_insert(j->item, pptr)->next;
742 free_commit_list(remoteheads);
743 strbuf_addch(&merge_msg, '\n');
744 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
745 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
746 finish(result_commit, buf.buf);
747 strbuf_release(&buf);
748 drop_save();
749 return 0;
752 static int suggest_conflicts(void)
754 FILE *fp;
755 int pos;
757 fp = fopen(git_path("MERGE_MSG"), "a");
758 if (!fp)
759 die("Could open %s for writing", git_path("MERGE_MSG"));
760 fprintf(fp, "\nConflicts:\n");
761 for (pos = 0; pos < active_nr; pos++) {
762 struct cache_entry *ce = active_cache[pos];
764 if (ce_stage(ce)) {
765 fprintf(fp, "\t%s\n", ce->name);
766 while (pos + 1 < active_nr &&
767 !strcmp(ce->name,
768 active_cache[pos + 1]->name))
769 pos++;
772 fclose(fp);
773 rerere();
774 printf("Automatic merge failed; "
775 "fix conflicts and then commit the result.\n");
776 return 1;
779 static struct commit *is_old_style_invocation(int argc, const char **argv)
781 struct commit *second_token = NULL;
782 if (argc > 1) {
783 unsigned char second_sha1[20];
785 if (get_sha1(argv[1], second_sha1))
786 return NULL;
787 second_token = lookup_commit_reference_gently(second_sha1, 0);
788 if (!second_token)
789 die("'%s' is not a commit", argv[1]);
790 if (hashcmp(second_token->object.sha1, head))
791 return NULL;
793 return second_token;
796 static int evaluate_result(void)
798 int cnt = 0;
799 struct rev_info rev;
801 /* Check how many files differ. */
802 init_revisions(&rev, "");
803 setup_revisions(0, NULL, &rev, NULL);
804 rev.diffopt.output_format |=
805 DIFF_FORMAT_CALLBACK;
806 rev.diffopt.format_callback = count_diff_files;
807 rev.diffopt.format_callback_data = &cnt;
808 run_diff_files(&rev, 0);
811 * Check how many unmerged entries are
812 * there.
814 cnt += count_unmerged_entries();
816 return cnt;
819 int cmd_merge(int argc, const char **argv, const char *prefix)
821 unsigned char result_tree[20];
822 struct strbuf buf = STRBUF_INIT;
823 const char *head_arg;
824 int flag, head_invalid = 0, i;
825 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
826 struct commit_list *common = NULL;
827 const char *best_strategy = NULL, *wt_strategy = NULL;
828 struct commit_list **remotes = &remoteheads;
830 setup_work_tree();
831 if (read_cache_unmerged())
832 die("You are in the middle of a conflicted merge.");
835 * Check if we are _not_ on a detached HEAD, i.e. if there is a
836 * current branch.
838 branch = resolve_ref("HEAD", head, 0, &flag);
839 if (branch && !prefixcmp(branch, "refs/heads/"))
840 branch += 11;
841 if (is_null_sha1(head))
842 head_invalid = 1;
844 git_config(git_merge_config, NULL);
846 /* for color.ui */
847 if (diff_use_color_default == -1)
848 diff_use_color_default = git_use_color_default;
850 argc = parse_options(argc, argv, builtin_merge_options,
851 builtin_merge_usage, 0);
852 if (verbosity < 0)
853 show_diffstat = 0;
855 if (squash) {
856 if (!allow_fast_forward)
857 die("You cannot combine --squash with --no-ff.");
858 option_commit = 0;
861 if (!argc)
862 usage_with_options(builtin_merge_usage,
863 builtin_merge_options);
866 * This could be traditional "merge <msg> HEAD <commit>..." and
867 * the way we can tell it is to see if the second token is HEAD,
868 * but some people might have misused the interface and used a
869 * committish that is the same as HEAD there instead.
870 * Traditional format never would have "-m" so it is an
871 * additional safety measure to check for it.
874 if (!have_message && is_old_style_invocation(argc, argv)) {
875 strbuf_addstr(&merge_msg, argv[0]);
876 head_arg = argv[1];
877 argv += 2;
878 argc -= 2;
879 } else if (head_invalid) {
880 struct object *remote_head;
882 * If the merged head is a valid one there is no reason
883 * to forbid "git merge" into a branch yet to be born.
884 * We do the same for "git pull".
886 if (argc != 1)
887 die("Can merge only exactly one commit into "
888 "empty head");
889 if (squash)
890 die("Squash commit into empty head not supported yet");
891 if (!allow_fast_forward)
892 die("Non-fast-forward commit does not make sense into "
893 "an empty head");
894 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
895 if (!remote_head)
896 die("%s - not something we can merge", argv[0]);
897 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
898 DIE_ON_ERR);
899 reset_hard(remote_head->sha1, 0);
900 return 0;
901 } else {
902 struct strbuf msg = STRBUF_INIT;
904 /* We are invoked directly as the first-class UI. */
905 head_arg = "HEAD";
908 * All the rest are the commits being merged;
909 * prepare the standard merge summary message to
910 * be appended to the given message. If remote
911 * is invalid we will die later in the common
912 * codepath so we discard the error in this
913 * loop.
915 for (i = 0; i < argc; i++)
916 merge_name(argv[i], &msg);
917 fmt_merge_msg(option_log, &msg, &merge_msg);
918 if (merge_msg.len)
919 strbuf_setlen(&merge_msg, merge_msg.len-1);
922 if (head_invalid || !argc)
923 usage_with_options(builtin_merge_usage,
924 builtin_merge_options);
926 strbuf_addstr(&buf, "merge");
927 for (i = 0; i < argc; i++)
928 strbuf_addf(&buf, " %s", argv[i]);
929 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
930 strbuf_reset(&buf);
932 for (i = 0; i < argc; i++) {
933 struct object *o;
934 struct commit *commit;
936 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
937 if (!o)
938 die("%s - not something we can merge", argv[i]);
939 commit = lookup_commit(o->sha1);
940 commit->util = (void *)argv[i];
941 remotes = &commit_list_insert(commit, remotes)->next;
943 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
944 setenv(buf.buf, argv[i], 1);
945 strbuf_reset(&buf);
948 if (!use_strategies) {
949 if (!remoteheads->next)
950 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
951 else
952 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
955 for (i = 0; i < use_strategies_nr; i++) {
956 if (use_strategies[i]->attr & NO_FAST_FORWARD)
957 allow_fast_forward = 0;
958 if (use_strategies[i]->attr & NO_TRIVIAL)
959 allow_trivial = 0;
962 if (!remoteheads->next)
963 common = get_merge_bases(lookup_commit(head),
964 remoteheads->item, 1);
965 else {
966 struct commit_list *list = remoteheads;
967 commit_list_insert(lookup_commit(head), &list);
968 common = get_octopus_merge_bases(list);
969 free(list);
972 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
973 DIE_ON_ERR);
975 if (!common)
976 ; /* No common ancestors found. We need a real merge. */
977 else if (!remoteheads->next && !common->next &&
978 common->item == remoteheads->item) {
980 * If head can reach all the merge then we are up to date.
981 * but first the most common case of merging one remote.
983 finish_up_to_date("Already up-to-date.");
984 return 0;
985 } else if (allow_fast_forward && !remoteheads->next &&
986 !common->next &&
987 !hashcmp(common->item->object.sha1, head)) {
988 /* Again the most common case of merging one remote. */
989 struct strbuf msg = STRBUF_INIT;
990 struct object *o;
991 char hex[41];
993 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
995 if (verbosity >= 0)
996 printf("Updating %s..%s\n",
997 hex,
998 find_unique_abbrev(remoteheads->item->object.sha1,
999 DEFAULT_ABBREV));
1000 strbuf_addstr(&msg, "Fast forward");
1001 if (have_message)
1002 strbuf_addstr(&msg,
1003 " (no commit created; -m option ignored)");
1004 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1005 0, NULL, OBJ_COMMIT);
1006 if (!o)
1007 return 1;
1009 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1010 return 1;
1012 finish(o->sha1, msg.buf);
1013 drop_save();
1014 return 0;
1015 } else if (!remoteheads->next && common->next)
1018 * We are not doing octopus and not fast forward. Need
1019 * a real merge.
1021 else if (!remoteheads->next && !common->next && option_commit) {
1023 * We are not doing octopus, not fast forward, and have
1024 * only one common.
1026 refresh_cache(REFRESH_QUIET);
1027 if (allow_trivial) {
1028 /* See if it is really trivial. */
1029 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1030 printf("Trying really trivial in-index merge...\n");
1031 if (!read_tree_trivial(common->item->object.sha1,
1032 head, remoteheads->item->object.sha1))
1033 return merge_trivial();
1034 printf("Nope.\n");
1036 } else {
1038 * An octopus. If we can reach all the remote we are up
1039 * to date.
1041 int up_to_date = 1;
1042 struct commit_list *j;
1044 for (j = remoteheads; j; j = j->next) {
1045 struct commit_list *common_one;
1048 * Here we *have* to calculate the individual
1049 * merge_bases again, otherwise "git merge HEAD^
1050 * HEAD^^" would be missed.
1052 common_one = get_merge_bases(lookup_commit(head),
1053 j->item, 1);
1054 if (hashcmp(common_one->item->object.sha1,
1055 j->item->object.sha1)) {
1056 up_to_date = 0;
1057 break;
1060 if (up_to_date) {
1061 finish_up_to_date("Already up-to-date. Yeeah!");
1062 return 0;
1066 /* We are going to make a new commit. */
1067 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1070 * At this point, we need a real merge. No matter what strategy
1071 * we use, it would operate on the index, possibly affecting the
1072 * working tree, and when resolved cleanly, have the desired
1073 * tree in the index -- this means that the index must be in
1074 * sync with the head commit. The strategies are responsible
1075 * to ensure this.
1077 if (use_strategies_nr != 1) {
1079 * Stash away the local changes so that we can try more
1080 * than one.
1082 save_state();
1083 } else {
1084 memcpy(stash, null_sha1, 20);
1087 for (i = 0; i < use_strategies_nr; i++) {
1088 int ret;
1089 if (i) {
1090 printf("Rewinding the tree to pristine...\n");
1091 restore_state();
1093 if (use_strategies_nr != 1)
1094 printf("Trying merge strategy %s...\n",
1095 use_strategies[i]->name);
1097 * Remember which strategy left the state in the working
1098 * tree.
1100 wt_strategy = use_strategies[i]->name;
1102 ret = try_merge_strategy(use_strategies[i]->name,
1103 common, head_arg);
1104 if (!option_commit && !ret) {
1105 merge_was_ok = 1;
1107 * This is necessary here just to avoid writing
1108 * the tree, but later we will *not* exit with
1109 * status code 1 because merge_was_ok is set.
1111 ret = 1;
1114 if (ret) {
1116 * The backend exits with 1 when conflicts are
1117 * left to be resolved, with 2 when it does not
1118 * handle the given merge at all.
1120 if (ret == 1) {
1121 int cnt = evaluate_result();
1123 if (best_cnt <= 0 || cnt <= best_cnt) {
1124 best_strategy = use_strategies[i]->name;
1125 best_cnt = cnt;
1128 if (merge_was_ok)
1129 break;
1130 else
1131 continue;
1134 /* Automerge succeeded. */
1135 write_tree_trivial(result_tree);
1136 automerge_was_ok = 1;
1137 break;
1141 * If we have a resulting tree, that means the strategy module
1142 * auto resolved the merge cleanly.
1144 if (automerge_was_ok)
1145 return finish_automerge(common, result_tree, wt_strategy);
1148 * Pick the result from the best strategy and have the user fix
1149 * it up.
1151 if (!best_strategy) {
1152 restore_state();
1153 if (use_strategies_nr > 1)
1154 fprintf(stderr,
1155 "No merge strategy handled the merge.\n");
1156 else
1157 fprintf(stderr, "Merge with strategy %s failed.\n",
1158 use_strategies[0]->name);
1159 return 2;
1160 } else if (best_strategy == wt_strategy)
1161 ; /* We already have its result in the working tree. */
1162 else {
1163 printf("Rewinding the tree to pristine...\n");
1164 restore_state();
1165 printf("Using the %s to prepare resolving by hand.\n",
1166 best_strategy);
1167 try_merge_strategy(best_strategy, common, head_arg);
1170 if (squash)
1171 finish(NULL, NULL);
1172 else {
1173 int fd;
1174 struct commit_list *j;
1176 for (j = remoteheads; j; j = j->next)
1177 strbuf_addf(&buf, "%s\n",
1178 sha1_to_hex(j->item->object.sha1));
1179 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1180 if (fd < 0)
1181 die("Could open %s for writing",
1182 git_path("MERGE_HEAD"));
1183 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1184 die("Could not write to %s", git_path("MERGE_HEAD"));
1185 close(fd);
1186 strbuf_addch(&merge_msg, '\n');
1187 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1188 if (fd < 0)
1189 die("Could open %s for writing", git_path("MERGE_MSG"));
1190 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1191 merge_msg.len)
1192 die("Could not write to %s", git_path("MERGE_MSG"));
1193 close(fd);
1194 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1195 if (fd < 0)
1196 die("Could open %s for writing", git_path("MERGE_MODE"));
1197 strbuf_reset(&buf);
1198 if (!allow_fast_forward)
1199 strbuf_addf(&buf, "no-ff");
1200 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1201 die("Could not write to %s", git_path("MERGE_MODE"));
1202 close(fd);
1205 if (merge_was_ok) {
1206 fprintf(stderr, "Automatic merge went well; "
1207 "stopped before committing as requested\n");
1208 return 0;
1209 } else
1210 return suggest_conflicts();