builtin-rm.c: explain and clarify the "local change" logic
[git/raj.git] / builtin-merge.c
blob7c2b90c70baed2c7f008c2b98ad26135ef12db00
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 write(fd, out.buf, out.len);
297 close(fd);
298 strbuf_release(&out);
301 static int run_hook(const char *name)
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);
330 static void finish(const unsigned char *new_head, const char *msg)
332 struct strbuf reflog_message = STRBUF_INIT;
334 if (!msg)
335 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
336 else {
337 if (verbosity >= 0)
338 printf("%s\n", msg);
339 strbuf_addf(&reflog_message, "%s: %s",
340 getenv("GIT_REFLOG_ACTION"), msg);
342 if (squash) {
343 squash_message();
344 } else {
345 if (verbosity >= 0 && !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);
353 * We ignore errors in 'gc --auto', since the
354 * user should see them.
356 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
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);
374 /* Run a post-merge hook */
375 run_hook("post-merge");
377 strbuf_release(&reflog_message);
380 /* Get the name for the merge commit's message. */
381 static void merge_name(const char *remote, struct strbuf *msg)
383 struct object *remote_head;
384 unsigned char branch_head[20], buf_sha[20];
385 struct strbuf buf = STRBUF_INIT;
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_addstr(&buf, "refs/heads/");
395 strbuf_addstr(&buf, remote);
396 resolve_ref(buf.buf, branch_head, 0, 0);
398 if (!hashcmp(remote_head->sha1, branch_head)) {
399 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
400 sha1_to_hex(branch_head), remote);
401 return;
404 /* See if remote matches <name>^^^.. or <name>~<number> */
405 for (len = 0, ptr = remote + strlen(remote);
406 remote < ptr && ptr[-1] == '^';
407 ptr--)
408 len++;
409 if (len)
410 early = 1;
411 else {
412 early = 0;
413 ptr = strrchr(remote, '~');
414 if (ptr) {
415 int seen_nonzero = 0;
417 len++; /* count ~ */
418 while (*++ptr && isdigit(*ptr)) {
419 seen_nonzero |= (*ptr != '0');
420 len++;
422 if (*ptr)
423 len = 0; /* not ...~<number> */
424 else if (seen_nonzero)
425 early = 1;
426 else if (len == 1)
427 early = 1; /* "name~" is "name~1"! */
430 if (len) {
431 struct strbuf truname = STRBUF_INIT;
432 strbuf_addstr(&truname, "refs/heads/");
433 strbuf_addstr(&truname, remote);
434 strbuf_setlen(&truname, truname.len - len);
435 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
436 strbuf_addf(msg,
437 "%s\t\tbranch '%s'%s of .\n",
438 sha1_to_hex(remote_head->sha1),
439 truname.buf + 11,
440 (early ? " (early part)" : ""));
441 return;
445 if (!strcmp(remote, "FETCH_HEAD") &&
446 !access(git_path("FETCH_HEAD"), R_OK)) {
447 FILE *fp;
448 struct strbuf line = STRBUF_INIT;
449 char *ptr;
451 fp = fopen(git_path("FETCH_HEAD"), "r");
452 if (!fp)
453 die("could not open %s for reading: %s",
454 git_path("FETCH_HEAD"), strerror(errno));
455 strbuf_getline(&line, fp, '\n');
456 fclose(fp);
457 ptr = strstr(line.buf, "\tnot-for-merge\t");
458 if (ptr)
459 strbuf_remove(&line, ptr-line.buf+1, 13);
460 strbuf_addbuf(msg, &line);
461 strbuf_release(&line);
462 return;
464 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
465 sha1_to_hex(remote_head->sha1), remote);
468 static int git_merge_config(const char *k, const char *v, void *cb)
470 if (branch && !prefixcmp(k, "branch.") &&
471 !prefixcmp(k + 7, branch) &&
472 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
473 const char **argv;
474 int argc;
475 char *buf;
477 buf = xstrdup(v);
478 argc = split_cmdline(buf, &argv);
479 if (argc < 0)
480 die("Bad branch.%s.mergeoptions string", branch);
481 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
482 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
483 argc++;
484 parse_options(argc, argv, builtin_merge_options,
485 builtin_merge_usage, 0);
486 free(buf);
489 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
490 show_diffstat = git_config_bool(k, v);
491 else if (!strcmp(k, "pull.twohead"))
492 return git_config_string(&pull_twohead, k, v);
493 else if (!strcmp(k, "pull.octopus"))
494 return git_config_string(&pull_octopus, k, v);
495 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
496 option_log = git_config_bool(k, v);
497 return git_diff_ui_config(k, v, cb);
500 static int read_tree_trivial(unsigned char *common, unsigned char *head,
501 unsigned char *one)
503 int i, nr_trees = 0;
504 struct tree *trees[MAX_UNPACK_TREES];
505 struct tree_desc t[MAX_UNPACK_TREES];
506 struct unpack_trees_options opts;
508 memset(&opts, 0, sizeof(opts));
509 opts.head_idx = 2;
510 opts.src_index = &the_index;
511 opts.dst_index = &the_index;
512 opts.update = 1;
513 opts.verbose_update = 1;
514 opts.trivial_merges_only = 1;
515 opts.merge = 1;
516 trees[nr_trees] = parse_tree_indirect(common);
517 if (!trees[nr_trees++])
518 return -1;
519 trees[nr_trees] = parse_tree_indirect(head);
520 if (!trees[nr_trees++])
521 return -1;
522 trees[nr_trees] = parse_tree_indirect(one);
523 if (!trees[nr_trees++])
524 return -1;
525 opts.fn = threeway_merge;
526 cache_tree_free(&active_cache_tree);
527 for (i = 0; i < nr_trees; i++) {
528 parse_tree(trees[i]);
529 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
531 if (unpack_trees(nr_trees, t, &opts))
532 return -1;
533 return 0;
536 static void write_tree_trivial(unsigned char *sha1)
538 if (write_cache_as_tree(sha1, 0, NULL))
539 die("git write-tree failed to write a tree");
542 static int try_merge_strategy(const char *strategy, struct commit_list *common,
543 const char *head_arg)
545 const char **args;
546 int i = 0, ret;
547 struct commit_list *j;
548 struct strbuf buf = STRBUF_INIT;
549 int index_fd;
550 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
552 index_fd = hold_locked_index(lock, 1);
553 refresh_cache(REFRESH_QUIET);
554 if (active_cache_changed &&
555 (write_cache(index_fd, active_cache, active_nr) ||
556 commit_locked_index(lock)))
557 return error("Unable to write index.");
558 rollback_lock_file(lock);
560 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
561 int clean;
562 struct commit *result;
563 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
564 int index_fd;
565 struct commit_list *reversed = NULL;
566 struct merge_options o;
568 if (remoteheads->next) {
569 error("Not handling anything other than two heads merge.");
570 return 2;
573 init_merge_options(&o);
574 if (!strcmp(strategy, "subtree"))
575 o.subtree_merge = 1;
577 o.branch1 = head_arg;
578 o.branch2 = remoteheads->item->util;
580 for (j = common; j; j = j->next)
581 commit_list_insert(j->item, &reversed);
583 index_fd = hold_locked_index(lock, 1);
584 clean = merge_recursive(&o, lookup_commit(head),
585 remoteheads->item, reversed, &result);
586 if (active_cache_changed &&
587 (write_cache(index_fd, active_cache, active_nr) ||
588 commit_locked_index(lock)))
589 die ("unable to write %s", get_index_file());
590 rollback_lock_file(lock);
591 return clean ? 0 : 1;
592 } else {
593 args = xmalloc((4 + commit_list_count(common) +
594 commit_list_count(remoteheads)) * sizeof(char *));
595 strbuf_addf(&buf, "merge-%s", strategy);
596 args[i++] = buf.buf;
597 for (j = common; j; j = j->next)
598 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
599 args[i++] = "--";
600 args[i++] = head_arg;
601 for (j = remoteheads; j; j = j->next)
602 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
603 args[i] = NULL;
604 ret = run_command_v_opt(args, RUN_GIT_CMD);
605 strbuf_release(&buf);
606 i = 1;
607 for (j = common; j; j = j->next)
608 free((void *)args[i++]);
609 i += 2;
610 for (j = remoteheads; j; j = j->next)
611 free((void *)args[i++]);
612 free(args);
613 discard_cache();
614 if (read_cache() < 0)
615 die("failed to read the cache");
616 return -ret;
620 static void count_diff_files(struct diff_queue_struct *q,
621 struct diff_options *opt, void *data)
623 int *count = data;
625 (*count) += q->nr;
628 static int count_unmerged_entries(void)
630 const struct index_state *state = &the_index;
631 int i, ret = 0;
633 for (i = 0; i < state->cache_nr; i++)
634 if (ce_stage(state->cache[i]))
635 ret++;
637 return ret;
640 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
642 struct tree *trees[MAX_UNPACK_TREES];
643 struct unpack_trees_options opts;
644 struct tree_desc t[MAX_UNPACK_TREES];
645 int i, fd, nr_trees = 0;
646 struct dir_struct dir;
647 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
649 refresh_cache(REFRESH_QUIET);
651 fd = hold_locked_index(lock_file, 1);
653 memset(&trees, 0, sizeof(trees));
654 memset(&opts, 0, sizeof(opts));
655 memset(&t, 0, sizeof(t));
656 memset(&dir, 0, sizeof(dir));
657 dir.show_ignored = 1;
658 dir.exclude_per_dir = ".gitignore";
659 opts.dir = &dir;
661 opts.head_idx = 1;
662 opts.src_index = &the_index;
663 opts.dst_index = &the_index;
664 opts.update = 1;
665 opts.verbose_update = 1;
666 opts.merge = 1;
667 opts.fn = twoway_merge;
669 trees[nr_trees] = parse_tree_indirect(head);
670 if (!trees[nr_trees++])
671 return -1;
672 trees[nr_trees] = parse_tree_indirect(remote);
673 if (!trees[nr_trees++])
674 return -1;
675 for (i = 0; i < nr_trees; i++) {
676 parse_tree(trees[i]);
677 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
679 if (unpack_trees(nr_trees, t, &opts))
680 return -1;
681 if (write_cache(fd, active_cache, active_nr) ||
682 commit_locked_index(lock_file))
683 die("unable to write new index file");
684 return 0;
687 static void split_merge_strategies(const char *string, struct strategy **list,
688 int *nr, int *alloc)
690 char *p, *q, *buf;
692 if (!string)
693 return;
695 buf = xstrdup(string);
696 q = buf;
697 for (;;) {
698 p = strchr(q, ' ');
699 if (!p) {
700 ALLOC_GROW(*list, *nr + 1, *alloc);
701 (*list)[(*nr)++].name = xstrdup(q);
702 free(buf);
703 return;
704 } else {
705 *p = '\0';
706 ALLOC_GROW(*list, *nr + 1, *alloc);
707 (*list)[(*nr)++].name = xstrdup(q);
708 q = ++p;
713 static void add_strategies(const char *string, unsigned attr)
715 struct strategy *list = NULL;
716 int list_alloc = 0, list_nr = 0, i;
718 memset(&list, 0, sizeof(list));
719 split_merge_strategies(string, &list, &list_nr, &list_alloc);
720 if (list) {
721 for (i = 0; i < list_nr; i++)
722 append_strategy(get_strategy(list[i].name));
723 return;
725 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
726 if (all_strategy[i].attr & attr)
727 append_strategy(&all_strategy[i]);
731 static int merge_trivial(void)
733 unsigned char result_tree[20], result_commit[20];
734 struct commit_list *parent = xmalloc(sizeof(*parent));
736 write_tree_trivial(result_tree);
737 printf("Wonderful.\n");
738 parent->item = lookup_commit(head);
739 parent->next = xmalloc(sizeof(*parent->next));
740 parent->next->item = remoteheads->item;
741 parent->next->next = NULL;
742 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
743 finish(result_commit, "In-index merge");
744 drop_save();
745 return 0;
748 static int finish_automerge(struct commit_list *common,
749 unsigned char *result_tree,
750 const char *wt_strategy)
752 struct commit_list *parents = NULL, *j;
753 struct strbuf buf = STRBUF_INIT;
754 unsigned char result_commit[20];
756 free_commit_list(common);
757 if (allow_fast_forward) {
758 parents = remoteheads;
759 commit_list_insert(lookup_commit(head), &parents);
760 parents = reduce_heads(parents);
761 } else {
762 struct commit_list **pptr = &parents;
764 pptr = &commit_list_insert(lookup_commit(head),
765 pptr)->next;
766 for (j = remoteheads; j; j = j->next)
767 pptr = &commit_list_insert(j->item, pptr)->next;
769 free_commit_list(remoteheads);
770 strbuf_addch(&merge_msg, '\n');
771 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
772 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
773 finish(result_commit, buf.buf);
774 strbuf_release(&buf);
775 drop_save();
776 return 0;
779 static int suggest_conflicts(void)
781 FILE *fp;
782 int pos;
784 fp = fopen(git_path("MERGE_MSG"), "a");
785 if (!fp)
786 die("Could open %s for writing", git_path("MERGE_MSG"));
787 fprintf(fp, "\nConflicts:\n");
788 for (pos = 0; pos < active_nr; pos++) {
789 struct cache_entry *ce = active_cache[pos];
791 if (ce_stage(ce)) {
792 fprintf(fp, "\t%s\n", ce->name);
793 while (pos + 1 < active_nr &&
794 !strcmp(ce->name,
795 active_cache[pos + 1]->name))
796 pos++;
799 fclose(fp);
800 rerere();
801 printf("Automatic merge failed; "
802 "fix conflicts and then commit the result.\n");
803 return 1;
806 static struct commit *is_old_style_invocation(int argc, const char **argv)
808 struct commit *second_token = NULL;
809 if (argc > 1) {
810 unsigned char second_sha1[20];
812 if (get_sha1(argv[1], second_sha1))
813 return NULL;
814 second_token = lookup_commit_reference_gently(second_sha1, 0);
815 if (!second_token)
816 die("'%s' is not a commit", argv[1]);
817 if (hashcmp(second_token->object.sha1, head))
818 return NULL;
820 return second_token;
823 static int evaluate_result(void)
825 int cnt = 0;
826 struct rev_info rev;
828 /* Check how many files differ. */
829 init_revisions(&rev, "");
830 setup_revisions(0, NULL, &rev, NULL);
831 rev.diffopt.output_format |=
832 DIFF_FORMAT_CALLBACK;
833 rev.diffopt.format_callback = count_diff_files;
834 rev.diffopt.format_callback_data = &cnt;
835 run_diff_files(&rev, 0);
838 * Check how many unmerged entries are
839 * there.
841 cnt += count_unmerged_entries();
843 return cnt;
846 int cmd_merge(int argc, const char **argv, const char *prefix)
848 unsigned char result_tree[20];
849 struct strbuf buf = STRBUF_INIT;
850 const char *head_arg;
851 int flag, head_invalid = 0, i;
852 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
853 struct commit_list *common = NULL;
854 const char *best_strategy = NULL, *wt_strategy = NULL;
855 struct commit_list **remotes = &remoteheads;
857 setup_work_tree();
858 if (read_cache_unmerged())
859 die("You are in the middle of a conflicted merge.");
862 * Check if we are _not_ on a detached HEAD, i.e. if there is a
863 * current branch.
865 branch = resolve_ref("HEAD", head, 0, &flag);
866 if (branch && !prefixcmp(branch, "refs/heads/"))
867 branch += 11;
868 if (is_null_sha1(head))
869 head_invalid = 1;
871 git_config(git_merge_config, NULL);
873 /* for color.ui */
874 if (diff_use_color_default == -1)
875 diff_use_color_default = git_use_color_default;
877 argc = parse_options(argc, argv, builtin_merge_options,
878 builtin_merge_usage, 0);
879 if (verbosity < 0)
880 show_diffstat = 0;
882 if (squash) {
883 if (!allow_fast_forward)
884 die("You cannot combine --squash with --no-ff.");
885 option_commit = 0;
888 if (!argc)
889 usage_with_options(builtin_merge_usage,
890 builtin_merge_options);
893 * This could be traditional "merge <msg> HEAD <commit>..." and
894 * the way we can tell it is to see if the second token is HEAD,
895 * but some people might have misused the interface and used a
896 * committish that is the same as HEAD there instead.
897 * Traditional format never would have "-m" so it is an
898 * additional safety measure to check for it.
901 if (!have_message && is_old_style_invocation(argc, argv)) {
902 strbuf_addstr(&merge_msg, argv[0]);
903 head_arg = argv[1];
904 argv += 2;
905 argc -= 2;
906 } else if (head_invalid) {
907 struct object *remote_head;
909 * If the merged head is a valid one there is no reason
910 * to forbid "git merge" into a branch yet to be born.
911 * We do the same for "git pull".
913 if (argc != 1)
914 die("Can merge only exactly one commit into "
915 "empty head");
916 if (squash)
917 die("Squash commit into empty head not supported yet");
918 if (!allow_fast_forward)
919 die("Non-fast-forward commit does not make sense into "
920 "an empty head");
921 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
922 if (!remote_head)
923 die("%s - not something we can merge", argv[0]);
924 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
925 DIE_ON_ERR);
926 reset_hard(remote_head->sha1, 0);
927 return 0;
928 } else {
929 struct strbuf msg = STRBUF_INIT;
931 /* We are invoked directly as the first-class UI. */
932 head_arg = "HEAD";
935 * All the rest are the commits being merged;
936 * prepare the standard merge summary message to
937 * be appended to the given message. If remote
938 * is invalid we will die later in the common
939 * codepath so we discard the error in this
940 * loop.
942 for (i = 0; i < argc; i++)
943 merge_name(argv[i], &msg);
944 fmt_merge_msg(option_log, &msg, &merge_msg);
945 if (merge_msg.len)
946 strbuf_setlen(&merge_msg, merge_msg.len-1);
949 if (head_invalid || !argc)
950 usage_with_options(builtin_merge_usage,
951 builtin_merge_options);
953 strbuf_addstr(&buf, "merge");
954 for (i = 0; i < argc; i++)
955 strbuf_addf(&buf, " %s", argv[i]);
956 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
957 strbuf_reset(&buf);
959 for (i = 0; i < argc; i++) {
960 struct object *o;
961 struct commit *commit;
963 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
964 if (!o)
965 die("%s - not something we can merge", argv[i]);
966 commit = lookup_commit(o->sha1);
967 commit->util = (void *)argv[i];
968 remotes = &commit_list_insert(commit, remotes)->next;
970 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
971 setenv(buf.buf, argv[i], 1);
972 strbuf_reset(&buf);
975 if (!use_strategies) {
976 if (!remoteheads->next)
977 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
978 else
979 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
982 for (i = 0; i < use_strategies_nr; i++) {
983 if (use_strategies[i]->attr & NO_FAST_FORWARD)
984 allow_fast_forward = 0;
985 if (use_strategies[i]->attr & NO_TRIVIAL)
986 allow_trivial = 0;
989 if (!remoteheads->next)
990 common = get_merge_bases(lookup_commit(head),
991 remoteheads->item, 1);
992 else {
993 struct commit_list *list = remoteheads;
994 commit_list_insert(lookup_commit(head), &list);
995 common = get_octopus_merge_bases(list);
996 free(list);
999 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1000 DIE_ON_ERR);
1002 if (!common)
1003 ; /* No common ancestors found. We need a real merge. */
1004 else if (!remoteheads->next && !common->next &&
1005 common->item == remoteheads->item) {
1007 * If head can reach all the merge then we are up to date.
1008 * but first the most common case of merging one remote.
1010 finish_up_to_date("Already up-to-date.");
1011 return 0;
1012 } else if (allow_fast_forward && !remoteheads->next &&
1013 !common->next &&
1014 !hashcmp(common->item->object.sha1, head)) {
1015 /* Again the most common case of merging one remote. */
1016 struct strbuf msg = STRBUF_INIT;
1017 struct object *o;
1018 char hex[41];
1020 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1022 if (verbosity >= 0)
1023 printf("Updating %s..%s\n",
1024 hex,
1025 find_unique_abbrev(remoteheads->item->object.sha1,
1026 DEFAULT_ABBREV));
1027 strbuf_addstr(&msg, "Fast forward");
1028 if (have_message)
1029 strbuf_addstr(&msg,
1030 " (no commit created; -m option ignored)");
1031 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1032 0, NULL, OBJ_COMMIT);
1033 if (!o)
1034 return 1;
1036 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1037 return 1;
1039 finish(o->sha1, msg.buf);
1040 drop_save();
1041 return 0;
1042 } else if (!remoteheads->next && common->next)
1045 * We are not doing octopus and not fast forward. Need
1046 * a real merge.
1048 else if (!remoteheads->next && !common->next && option_commit) {
1050 * We are not doing octopus, not fast forward, and have
1051 * only one common.
1053 refresh_cache(REFRESH_QUIET);
1054 if (allow_trivial) {
1055 /* See if it is really trivial. */
1056 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1057 printf("Trying really trivial in-index merge...\n");
1058 if (!read_tree_trivial(common->item->object.sha1,
1059 head, remoteheads->item->object.sha1))
1060 return merge_trivial();
1061 printf("Nope.\n");
1063 } else {
1065 * An octopus. If we can reach all the remote we are up
1066 * to date.
1068 int up_to_date = 1;
1069 struct commit_list *j;
1071 for (j = remoteheads; j; j = j->next) {
1072 struct commit_list *common_one;
1075 * Here we *have* to calculate the individual
1076 * merge_bases again, otherwise "git merge HEAD^
1077 * HEAD^^" would be missed.
1079 common_one = get_merge_bases(lookup_commit(head),
1080 j->item, 1);
1081 if (hashcmp(common_one->item->object.sha1,
1082 j->item->object.sha1)) {
1083 up_to_date = 0;
1084 break;
1087 if (up_to_date) {
1088 finish_up_to_date("Already up-to-date. Yeeah!");
1089 return 0;
1093 /* We are going to make a new commit. */
1094 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1097 * At this point, we need a real merge. No matter what strategy
1098 * we use, it would operate on the index, possibly affecting the
1099 * working tree, and when resolved cleanly, have the desired
1100 * tree in the index -- this means that the index must be in
1101 * sync with the head commit. The strategies are responsible
1102 * to ensure this.
1104 if (use_strategies_nr != 1) {
1106 * Stash away the local changes so that we can try more
1107 * than one.
1109 save_state();
1110 } else {
1111 memcpy(stash, null_sha1, 20);
1114 for (i = 0; i < use_strategies_nr; i++) {
1115 int ret;
1116 if (i) {
1117 printf("Rewinding the tree to pristine...\n");
1118 restore_state();
1120 if (use_strategies_nr != 1)
1121 printf("Trying merge strategy %s...\n",
1122 use_strategies[i]->name);
1124 * Remember which strategy left the state in the working
1125 * tree.
1127 wt_strategy = use_strategies[i]->name;
1129 ret = try_merge_strategy(use_strategies[i]->name,
1130 common, head_arg);
1131 if (!option_commit && !ret) {
1132 merge_was_ok = 1;
1134 * This is necessary here just to avoid writing
1135 * the tree, but later we will *not* exit with
1136 * status code 1 because merge_was_ok is set.
1138 ret = 1;
1141 if (ret) {
1143 * The backend exits with 1 when conflicts are
1144 * left to be resolved, with 2 when it does not
1145 * handle the given merge at all.
1147 if (ret == 1) {
1148 int cnt = evaluate_result();
1150 if (best_cnt <= 0 || cnt <= best_cnt) {
1151 best_strategy = use_strategies[i]->name;
1152 best_cnt = cnt;
1155 if (merge_was_ok)
1156 break;
1157 else
1158 continue;
1161 /* Automerge succeeded. */
1162 write_tree_trivial(result_tree);
1163 automerge_was_ok = 1;
1164 break;
1168 * If we have a resulting tree, that means the strategy module
1169 * auto resolved the merge cleanly.
1171 if (automerge_was_ok)
1172 return finish_automerge(common, result_tree, wt_strategy);
1175 * Pick the result from the best strategy and have the user fix
1176 * it up.
1178 if (!best_strategy) {
1179 restore_state();
1180 if (use_strategies_nr > 1)
1181 fprintf(stderr,
1182 "No merge strategy handled the merge.\n");
1183 else
1184 fprintf(stderr, "Merge with strategy %s failed.\n",
1185 use_strategies[0]->name);
1186 return 2;
1187 } else if (best_strategy == wt_strategy)
1188 ; /* We already have its result in the working tree. */
1189 else {
1190 printf("Rewinding the tree to pristine...\n");
1191 restore_state();
1192 printf("Using the %s to prepare resolving by hand.\n",
1193 best_strategy);
1194 try_merge_strategy(best_strategy, common, head_arg);
1197 if (squash)
1198 finish(NULL, NULL);
1199 else {
1200 int fd;
1201 struct commit_list *j;
1203 for (j = remoteheads; j; j = j->next)
1204 strbuf_addf(&buf, "%s\n",
1205 sha1_to_hex(j->item->object.sha1));
1206 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1207 if (fd < 0)
1208 die("Could open %s for writing",
1209 git_path("MERGE_HEAD"));
1210 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1211 die("Could not write to %s", git_path("MERGE_HEAD"));
1212 close(fd);
1213 strbuf_addch(&merge_msg, '\n');
1214 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1215 if (fd < 0)
1216 die("Could open %s for writing", git_path("MERGE_MSG"));
1217 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1218 merge_msg.len)
1219 die("Could not write to %s", git_path("MERGE_MSG"));
1220 close(fd);
1221 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1222 if (fd < 0)
1223 die("Could open %s for writing", git_path("MERGE_MODE"));
1224 strbuf_reset(&buf);
1225 if (!allow_fast_forward)
1226 strbuf_addf(&buf, "no-ff");
1227 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1228 die("Could not write to %s", git_path("MERGE_MODE"));
1229 close(fd);
1232 if (merge_was_ok) {
1233 fprintf(stderr, "Automatic merge went well; "
1234 "stopped before committing as requested\n");
1235 return 0;
1236 } else
1237 return suggest_conflicts();