Merge branch 'maint'
[git/trast.git] / builtin-merge.c
blobcf869751b41c256363bf5f0c465e46684e2920b8
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 int run_hook(const char *name)
305 struct child_process hook;
306 const char *argv[3], *env[2];
307 char index[PATH_MAX];
309 argv[0] = git_path("hooks/%s", name);
310 if (access(argv[0], X_OK) < 0)
311 return 0;
313 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
314 env[0] = index;
315 env[1] = NULL;
317 if (squash)
318 argv[1] = "1";
319 else
320 argv[1] = "0";
321 argv[2] = NULL;
323 memset(&hook, 0, sizeof(hook));
324 hook.argv = argv;
325 hook.no_stdin = 1;
326 hook.stdout_to_stderr = 1;
327 hook.env = env;
329 return run_command(&hook);
332 static void finish(const unsigned char *new_head, const char *msg)
334 struct strbuf reflog_message = STRBUF_INIT;
336 if (!msg)
337 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
338 else {
339 if (verbosity >= 0)
340 printf("%s\n", msg);
341 strbuf_addf(&reflog_message, "%s: %s",
342 getenv("GIT_REFLOG_ACTION"), msg);
344 if (squash) {
345 squash_message();
346 } else {
347 if (verbosity >= 0 && !merge_msg.len)
348 printf("No merge message -- not updating HEAD\n");
349 else {
350 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
351 update_ref(reflog_message.buf, "HEAD",
352 new_head, head, 0,
353 DIE_ON_ERR);
355 * We ignore errors in 'gc --auto', since the
356 * user should see them.
358 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
361 if (new_head && show_diffstat) {
362 struct diff_options opts;
363 diff_setup(&opts);
364 opts.output_format |=
365 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
366 opts.detect_rename = DIFF_DETECT_RENAME;
367 if (diff_use_color_default > 0)
368 DIFF_OPT_SET(&opts, COLOR_DIFF);
369 if (diff_setup_done(&opts) < 0)
370 die("diff_setup_done failed");
371 diff_tree_sha1(head, new_head, "", &opts);
372 diffcore_std(&opts);
373 diff_flush(&opts);
376 /* Run a post-merge hook */
377 run_hook("post-merge");
379 strbuf_release(&reflog_message);
382 /* Get the name for the merge commit's message. */
383 static void merge_name(const char *remote, struct strbuf *msg)
385 struct object *remote_head;
386 unsigned char branch_head[20], buf_sha[20];
387 struct strbuf buf = STRBUF_INIT;
388 const char *ptr;
389 int len, early;
391 memset(branch_head, 0, sizeof(branch_head));
392 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
393 if (!remote_head)
394 die("'%s' does not point to a commit", remote);
396 strbuf_addstr(&buf, "refs/heads/");
397 strbuf_addstr(&buf, remote);
398 resolve_ref(buf.buf, branch_head, 0, 0);
400 if (!hashcmp(remote_head->sha1, branch_head)) {
401 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
402 sha1_to_hex(branch_head), remote);
403 return;
406 /* See if remote matches <name>^^^.. or <name>~<number> */
407 for (len = 0, ptr = remote + strlen(remote);
408 remote < ptr && ptr[-1] == '^';
409 ptr--)
410 len++;
411 if (len)
412 early = 1;
413 else {
414 early = 0;
415 ptr = strrchr(remote, '~');
416 if (ptr) {
417 int seen_nonzero = 0;
419 len++; /* count ~ */
420 while (*++ptr && isdigit(*ptr)) {
421 seen_nonzero |= (*ptr != '0');
422 len++;
424 if (*ptr)
425 len = 0; /* not ...~<number> */
426 else if (seen_nonzero)
427 early = 1;
428 else if (len == 1)
429 early = 1; /* "name~" is "name~1"! */
432 if (len) {
433 struct strbuf truname = STRBUF_INIT;
434 strbuf_addstr(&truname, "refs/heads/");
435 strbuf_addstr(&truname, remote);
436 strbuf_setlen(&truname, truname.len - len);
437 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
438 strbuf_addf(msg,
439 "%s\t\tbranch '%s'%s of .\n",
440 sha1_to_hex(remote_head->sha1),
441 truname.buf + 11,
442 (early ? " (early part)" : ""));
443 return;
447 if (!strcmp(remote, "FETCH_HEAD") &&
448 !access(git_path("FETCH_HEAD"), R_OK)) {
449 FILE *fp;
450 struct strbuf line = STRBUF_INIT;
451 char *ptr;
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;
466 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
467 sha1_to_hex(remote_head->sha1), remote);
470 static int git_merge_config(const char *k, const char *v, void *cb)
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);
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);
502 static int read_tree_trivial(unsigned char *common, unsigned char *head,
503 unsigned char *one)
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);
533 if (unpack_trees(nr_trees, t, &opts))
534 return -1;
535 return 0;
538 static void write_tree_trivial(unsigned char *sha1)
540 if (write_cache_as_tree(sha1, 0, NULL))
541 die("git write-tree failed to write a tree");
544 static int try_merge_strategy(const char *strategy, struct commit_list *common,
545 const char *head_arg)
547 const char **args;
548 int i = 0, ret;
549 struct commit_list *j;
550 struct strbuf buf = STRBUF_INIT;
551 int index_fd;
552 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
554 index_fd = hold_locked_index(lock, 1);
555 refresh_cache(REFRESH_QUIET);
556 if (active_cache_changed &&
557 (write_cache(index_fd, active_cache, active_nr) ||
558 commit_locked_index(lock)))
559 return error("Unable to write index.");
560 rollback_lock_file(lock);
562 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
563 int clean;
564 struct commit *result;
565 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
566 int index_fd;
567 struct commit_list *reversed = NULL;
568 struct merge_options o;
570 if (remoteheads->next) {
571 error("Not handling anything other than two heads merge.");
572 return 2;
575 init_merge_options(&o);
576 if (!strcmp(strategy, "subtree"))
577 o.subtree_merge = 1;
579 o.branch1 = head_arg;
580 o.branch2 = remoteheads->item->util;
582 for (j = common; j; j = j->next)
583 commit_list_insert(j->item, &reversed);
585 index_fd = hold_locked_index(lock, 1);
586 clean = merge_recursive(&o, lookup_commit(head),
587 remoteheads->item, reversed, &result);
588 if (active_cache_changed &&
589 (write_cache(index_fd, active_cache, active_nr) ||
590 commit_locked_index(lock)))
591 die ("unable to write %s", get_index_file());
592 rollback_lock_file(lock);
593 return clean ? 0 : 1;
594 } else {
595 args = xmalloc((4 + commit_list_count(common) +
596 commit_list_count(remoteheads)) * sizeof(char *));
597 strbuf_addf(&buf, "merge-%s", strategy);
598 args[i++] = buf.buf;
599 for (j = common; j; j = j->next)
600 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
601 args[i++] = "--";
602 args[i++] = head_arg;
603 for (j = remoteheads; j; j = j->next)
604 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
605 args[i] = NULL;
606 ret = run_command_v_opt(args, RUN_GIT_CMD);
607 strbuf_release(&buf);
608 i = 1;
609 for (j = common; j; j = j->next)
610 free((void *)args[i++]);
611 i += 2;
612 for (j = remoteheads; j; j = j->next)
613 free((void *)args[i++]);
614 free(args);
615 discard_cache();
616 if (read_cache() < 0)
617 die("failed to read the cache");
618 return -ret;
622 static void count_diff_files(struct diff_queue_struct *q,
623 struct diff_options *opt, void *data)
625 int *count = data;
627 (*count) += q->nr;
630 static int count_unmerged_entries(void)
632 const struct index_state *state = &the_index;
633 int i, ret = 0;
635 for (i = 0; i < state->cache_nr; i++)
636 if (ce_stage(state->cache[i]))
637 ret++;
639 return ret;
642 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
644 struct tree *trees[MAX_UNPACK_TREES];
645 struct unpack_trees_options opts;
646 struct tree_desc t[MAX_UNPACK_TREES];
647 int i, fd, nr_trees = 0;
648 struct dir_struct dir;
649 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
651 refresh_cache(REFRESH_QUIET);
653 fd = hold_locked_index(lock_file, 1);
655 memset(&trees, 0, sizeof(trees));
656 memset(&opts, 0, sizeof(opts));
657 memset(&t, 0, sizeof(t));
658 memset(&dir, 0, sizeof(dir));
659 dir.show_ignored = 1;
660 dir.exclude_per_dir = ".gitignore";
661 opts.dir = &dir;
663 opts.head_idx = 1;
664 opts.src_index = &the_index;
665 opts.dst_index = &the_index;
666 opts.update = 1;
667 opts.verbose_update = 1;
668 opts.merge = 1;
669 opts.fn = twoway_merge;
671 trees[nr_trees] = parse_tree_indirect(head);
672 if (!trees[nr_trees++])
673 return -1;
674 trees[nr_trees] = parse_tree_indirect(remote);
675 if (!trees[nr_trees++])
676 return -1;
677 for (i = 0; i < nr_trees; i++) {
678 parse_tree(trees[i]);
679 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
681 if (unpack_trees(nr_trees, t, &opts))
682 return -1;
683 if (write_cache(fd, active_cache, active_nr) ||
684 commit_locked_index(lock_file))
685 die("unable to write new index file");
686 return 0;
689 static void split_merge_strategies(const char *string, struct strategy **list,
690 int *nr, int *alloc)
692 char *p, *q, *buf;
694 if (!string)
695 return;
697 buf = xstrdup(string);
698 q = buf;
699 for (;;) {
700 p = strchr(q, ' ');
701 if (!p) {
702 ALLOC_GROW(*list, *nr + 1, *alloc);
703 (*list)[(*nr)++].name = xstrdup(q);
704 free(buf);
705 return;
706 } else {
707 *p = '\0';
708 ALLOC_GROW(*list, *nr + 1, *alloc);
709 (*list)[(*nr)++].name = xstrdup(q);
710 q = ++p;
715 static void add_strategies(const char *string, unsigned attr)
717 struct strategy *list = NULL;
718 int list_alloc = 0, list_nr = 0, i;
720 memset(&list, 0, sizeof(list));
721 split_merge_strategies(string, &list, &list_nr, &list_alloc);
722 if (list) {
723 for (i = 0; i < list_nr; i++)
724 append_strategy(get_strategy(list[i].name));
725 return;
727 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
728 if (all_strategy[i].attr & attr)
729 append_strategy(&all_strategy[i]);
733 static int merge_trivial(void)
735 unsigned char result_tree[20], result_commit[20];
736 struct commit_list *parent = xmalloc(sizeof(*parent));
738 write_tree_trivial(result_tree);
739 printf("Wonderful.\n");
740 parent->item = lookup_commit(head);
741 parent->next = xmalloc(sizeof(*parent->next));
742 parent->next->item = remoteheads->item;
743 parent->next->next = NULL;
744 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
745 finish(result_commit, "In-index merge");
746 drop_save();
747 return 0;
750 static int finish_automerge(struct commit_list *common,
751 unsigned char *result_tree,
752 const char *wt_strategy)
754 struct commit_list *parents = NULL, *j;
755 struct strbuf buf = STRBUF_INIT;
756 unsigned char result_commit[20];
758 free_commit_list(common);
759 if (allow_fast_forward) {
760 parents = remoteheads;
761 commit_list_insert(lookup_commit(head), &parents);
762 parents = reduce_heads(parents);
763 } else {
764 struct commit_list **pptr = &parents;
766 pptr = &commit_list_insert(lookup_commit(head),
767 pptr)->next;
768 for (j = remoteheads; j; j = j->next)
769 pptr = &commit_list_insert(j->item, pptr)->next;
771 free_commit_list(remoteheads);
772 strbuf_addch(&merge_msg, '\n');
773 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
774 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
775 finish(result_commit, buf.buf);
776 strbuf_release(&buf);
777 drop_save();
778 return 0;
781 static int suggest_conflicts(void)
783 FILE *fp;
784 int pos;
786 fp = fopen(git_path("MERGE_MSG"), "a");
787 if (!fp)
788 die("Could open %s for writing", git_path("MERGE_MSG"));
789 fprintf(fp, "\nConflicts:\n");
790 for (pos = 0; pos < active_nr; pos++) {
791 struct cache_entry *ce = active_cache[pos];
793 if (ce_stage(ce)) {
794 fprintf(fp, "\t%s\n", ce->name);
795 while (pos + 1 < active_nr &&
796 !strcmp(ce->name,
797 active_cache[pos + 1]->name))
798 pos++;
801 fclose(fp);
802 rerere();
803 printf("Automatic merge failed; "
804 "fix conflicts and then commit the result.\n");
805 return 1;
808 static struct commit *is_old_style_invocation(int argc, const char **argv)
810 struct commit *second_token = NULL;
811 if (argc > 1) {
812 unsigned char second_sha1[20];
814 if (get_sha1(argv[1], second_sha1))
815 return NULL;
816 second_token = lookup_commit_reference_gently(second_sha1, 0);
817 if (!second_token)
818 die("'%s' is not a commit", argv[1]);
819 if (hashcmp(second_token->object.sha1, head))
820 return NULL;
822 return second_token;
825 static int evaluate_result(void)
827 int cnt = 0;
828 struct rev_info rev;
830 /* Check how many files differ. */
831 init_revisions(&rev, "");
832 setup_revisions(0, NULL, &rev, NULL);
833 rev.diffopt.output_format |=
834 DIFF_FORMAT_CALLBACK;
835 rev.diffopt.format_callback = count_diff_files;
836 rev.diffopt.format_callback_data = &cnt;
837 run_diff_files(&rev, 0);
840 * Check how many unmerged entries are
841 * there.
843 cnt += count_unmerged_entries();
845 return cnt;
848 int cmd_merge(int argc, const char **argv, const char *prefix)
850 unsigned char result_tree[20];
851 struct strbuf buf = STRBUF_INIT;
852 const char *head_arg;
853 int flag, head_invalid = 0, i;
854 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
855 struct commit_list *common = NULL;
856 const char *best_strategy = NULL, *wt_strategy = NULL;
857 struct commit_list **remotes = &remoteheads;
859 setup_work_tree();
860 if (read_cache_unmerged())
861 die("You are in the middle of a conflicted merge.");
864 * Check if we are _not_ on a detached HEAD, i.e. if there is a
865 * current branch.
867 branch = resolve_ref("HEAD", head, 0, &flag);
868 if (branch && !prefixcmp(branch, "refs/heads/"))
869 branch += 11;
870 if (is_null_sha1(head))
871 head_invalid = 1;
873 git_config(git_merge_config, NULL);
875 /* for color.ui */
876 if (diff_use_color_default == -1)
877 diff_use_color_default = git_use_color_default;
879 argc = parse_options(argc, argv, builtin_merge_options,
880 builtin_merge_usage, 0);
881 if (verbosity < 0)
882 show_diffstat = 0;
884 if (squash) {
885 if (!allow_fast_forward)
886 die("You cannot combine --squash with --no-ff.");
887 option_commit = 0;
890 if (!argc)
891 usage_with_options(builtin_merge_usage,
892 builtin_merge_options);
895 * This could be traditional "merge <msg> HEAD <commit>..." and
896 * the way we can tell it is to see if the second token is HEAD,
897 * but some people might have misused the interface and used a
898 * committish that is the same as HEAD there instead.
899 * Traditional format never would have "-m" so it is an
900 * additional safety measure to check for it.
903 if (!have_message && is_old_style_invocation(argc, argv)) {
904 strbuf_addstr(&merge_msg, argv[0]);
905 head_arg = argv[1];
906 argv += 2;
907 argc -= 2;
908 } else if (head_invalid) {
909 struct object *remote_head;
911 * If the merged head is a valid one there is no reason
912 * to forbid "git merge" into a branch yet to be born.
913 * We do the same for "git pull".
915 if (argc != 1)
916 die("Can merge only exactly one commit into "
917 "empty head");
918 if (squash)
919 die("Squash commit into empty head not supported yet");
920 if (!allow_fast_forward)
921 die("Non-fast-forward commit does not make sense into "
922 "an empty head");
923 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
924 if (!remote_head)
925 die("%s - not something we can merge", argv[0]);
926 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
927 DIE_ON_ERR);
928 reset_hard(remote_head->sha1, 0);
929 return 0;
930 } else {
931 struct strbuf msg = STRBUF_INIT;
933 /* We are invoked directly as the first-class UI. */
934 head_arg = "HEAD";
937 * All the rest are the commits being merged;
938 * prepare the standard merge summary message to
939 * be appended to the given message. If remote
940 * is invalid we will die later in the common
941 * codepath so we discard the error in this
942 * loop.
944 for (i = 0; i < argc; i++)
945 merge_name(argv[i], &msg);
946 fmt_merge_msg(option_log, &msg, &merge_msg);
947 if (merge_msg.len)
948 strbuf_setlen(&merge_msg, merge_msg.len-1);
951 if (head_invalid || !argc)
952 usage_with_options(builtin_merge_usage,
953 builtin_merge_options);
955 strbuf_addstr(&buf, "merge");
956 for (i = 0; i < argc; i++)
957 strbuf_addf(&buf, " %s", argv[i]);
958 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
959 strbuf_reset(&buf);
961 for (i = 0; i < argc; i++) {
962 struct object *o;
963 struct commit *commit;
965 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
966 if (!o)
967 die("%s - not something we can merge", argv[i]);
968 commit = lookup_commit(o->sha1);
969 commit->util = (void *)argv[i];
970 remotes = &commit_list_insert(commit, remotes)->next;
972 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
973 setenv(buf.buf, argv[i], 1);
974 strbuf_reset(&buf);
977 if (!use_strategies) {
978 if (!remoteheads->next)
979 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
980 else
981 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
984 for (i = 0; i < use_strategies_nr; i++) {
985 if (use_strategies[i]->attr & NO_FAST_FORWARD)
986 allow_fast_forward = 0;
987 if (use_strategies[i]->attr & NO_TRIVIAL)
988 allow_trivial = 0;
991 if (!remoteheads->next)
992 common = get_merge_bases(lookup_commit(head),
993 remoteheads->item, 1);
994 else {
995 struct commit_list *list = remoteheads;
996 commit_list_insert(lookup_commit(head), &list);
997 common = get_octopus_merge_bases(list);
998 free(list);
1001 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1002 DIE_ON_ERR);
1004 if (!common)
1005 ; /* No common ancestors found. We need a real merge. */
1006 else if (!remoteheads->next && !common->next &&
1007 common->item == remoteheads->item) {
1009 * If head can reach all the merge then we are up to date.
1010 * but first the most common case of merging one remote.
1012 finish_up_to_date("Already up-to-date.");
1013 return 0;
1014 } else if (allow_fast_forward && !remoteheads->next &&
1015 !common->next &&
1016 !hashcmp(common->item->object.sha1, head)) {
1017 /* Again the most common case of merging one remote. */
1018 struct strbuf msg = STRBUF_INIT;
1019 struct object *o;
1020 char hex[41];
1022 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1024 if (verbosity >= 0)
1025 printf("Updating %s..%s\n",
1026 hex,
1027 find_unique_abbrev(remoteheads->item->object.sha1,
1028 DEFAULT_ABBREV));
1029 strbuf_addstr(&msg, "Fast forward");
1030 if (have_message)
1031 strbuf_addstr(&msg,
1032 " (no commit created; -m option ignored)");
1033 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1034 0, NULL, OBJ_COMMIT);
1035 if (!o)
1036 return 1;
1038 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1039 return 1;
1041 finish(o->sha1, msg.buf);
1042 drop_save();
1043 return 0;
1044 } else if (!remoteheads->next && common->next)
1047 * We are not doing octopus and not fast forward. Need
1048 * a real merge.
1050 else if (!remoteheads->next && !common->next && option_commit) {
1052 * We are not doing octopus, not fast forward, and have
1053 * only one common.
1055 refresh_cache(REFRESH_QUIET);
1056 if (allow_trivial) {
1057 /* See if it is really trivial. */
1058 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1059 printf("Trying really trivial in-index merge...\n");
1060 if (!read_tree_trivial(common->item->object.sha1,
1061 head, remoteheads->item->object.sha1))
1062 return merge_trivial();
1063 printf("Nope.\n");
1065 } else {
1067 * An octopus. If we can reach all the remote we are up
1068 * to date.
1070 int up_to_date = 1;
1071 struct commit_list *j;
1073 for (j = remoteheads; j; j = j->next) {
1074 struct commit_list *common_one;
1077 * Here we *have* to calculate the individual
1078 * merge_bases again, otherwise "git merge HEAD^
1079 * HEAD^^" would be missed.
1081 common_one = get_merge_bases(lookup_commit(head),
1082 j->item, 1);
1083 if (hashcmp(common_one->item->object.sha1,
1084 j->item->object.sha1)) {
1085 up_to_date = 0;
1086 break;
1089 if (up_to_date) {
1090 finish_up_to_date("Already up-to-date. Yeeah!");
1091 return 0;
1095 /* We are going to make a new commit. */
1096 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1099 * At this point, we need a real merge. No matter what strategy
1100 * we use, it would operate on the index, possibly affecting the
1101 * working tree, and when resolved cleanly, have the desired
1102 * tree in the index -- this means that the index must be in
1103 * sync with the head commit. The strategies are responsible
1104 * to ensure this.
1106 if (use_strategies_nr != 1) {
1108 * Stash away the local changes so that we can try more
1109 * than one.
1111 save_state();
1112 } else {
1113 memcpy(stash, null_sha1, 20);
1116 for (i = 0; i < use_strategies_nr; i++) {
1117 int ret;
1118 if (i) {
1119 printf("Rewinding the tree to pristine...\n");
1120 restore_state();
1122 if (use_strategies_nr != 1)
1123 printf("Trying merge strategy %s...\n",
1124 use_strategies[i]->name);
1126 * Remember which strategy left the state in the working
1127 * tree.
1129 wt_strategy = use_strategies[i]->name;
1131 ret = try_merge_strategy(use_strategies[i]->name,
1132 common, head_arg);
1133 if (!option_commit && !ret) {
1134 merge_was_ok = 1;
1136 * This is necessary here just to avoid writing
1137 * the tree, but later we will *not* exit with
1138 * status code 1 because merge_was_ok is set.
1140 ret = 1;
1143 if (ret) {
1145 * The backend exits with 1 when conflicts are
1146 * left to be resolved, with 2 when it does not
1147 * handle the given merge at all.
1149 if (ret == 1) {
1150 int cnt = evaluate_result();
1152 if (best_cnt <= 0 || cnt <= best_cnt) {
1153 best_strategy = use_strategies[i]->name;
1154 best_cnt = cnt;
1157 if (merge_was_ok)
1158 break;
1159 else
1160 continue;
1163 /* Automerge succeeded. */
1164 write_tree_trivial(result_tree);
1165 automerge_was_ok = 1;
1166 break;
1170 * If we have a resulting tree, that means the strategy module
1171 * auto resolved the merge cleanly.
1173 if (automerge_was_ok)
1174 return finish_automerge(common, result_tree, wt_strategy);
1177 * Pick the result from the best strategy and have the user fix
1178 * it up.
1180 if (!best_strategy) {
1181 restore_state();
1182 if (use_strategies_nr > 1)
1183 fprintf(stderr,
1184 "No merge strategy handled the merge.\n");
1185 else
1186 fprintf(stderr, "Merge with strategy %s failed.\n",
1187 use_strategies[0]->name);
1188 return 2;
1189 } else if (best_strategy == wt_strategy)
1190 ; /* We already have its result in the working tree. */
1191 else {
1192 printf("Rewinding the tree to pristine...\n");
1193 restore_state();
1194 printf("Using the %s to prepare resolving by hand.\n",
1195 best_strategy);
1196 try_merge_strategy(best_strategy, common, head_arg);
1199 if (squash)
1200 finish(NULL, NULL);
1201 else {
1202 int fd;
1203 struct commit_list *j;
1205 for (j = remoteheads; j; j = j->next)
1206 strbuf_addf(&buf, "%s\n",
1207 sha1_to_hex(j->item->object.sha1));
1208 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1209 if (fd < 0)
1210 die("Could open %s for writing",
1211 git_path("MERGE_HEAD"));
1212 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1213 die("Could not write to %s", git_path("MERGE_HEAD"));
1214 close(fd);
1215 strbuf_addch(&merge_msg, '\n');
1216 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1217 if (fd < 0)
1218 die("Could open %s for writing", git_path("MERGE_MSG"));
1219 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1220 merge_msg.len)
1221 die("Could not write to %s", git_path("MERGE_MSG"));
1222 close(fd);
1223 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1224 if (fd < 0)
1225 die("Could open %s for writing", git_path("MERGE_MODE"));
1226 strbuf_reset(&buf);
1227 if (!allow_fast_forward)
1228 strbuf_addf(&buf, "no-ff");
1229 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1230 die("Could not write to %s", git_path("MERGE_MODE"));
1231 close(fd);
1234 if (merge_was_ok) {
1235 fprintf(stderr, "Automatic merge went well; "
1236 "stopped before committing as requested\n");
1237 return 0;
1238 } else
1239 return suggest_conflicts();