Merge branch 'maint-1.6.0' into maint
[git/dscho.git] / builtin-merge.c
blobf1c84d759dd44f661fb76741d528e43702dfc901
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 fast_forward_only;
47 static int allow_trivial = 1, have_message;
48 static struct strbuf merge_msg;
49 static struct commit_list *remoteheads;
50 static unsigned char head[20], stash[20];
51 static struct strategy **use_strategies;
52 static size_t use_strategies_nr, use_strategies_alloc;
53 static const char *branch;
54 static int verbosity;
56 static struct strategy all_strategy[] = {
57 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
58 { "octopus", DEFAULT_OCTOPUS },
59 { "resolve", 0 },
60 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
61 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
64 static const char *pull_twohead, *pull_octopus;
66 static int option_parse_message(const struct option *opt,
67 const char *arg, int unset)
69 struct strbuf *buf = opt->value;
71 if (unset)
72 strbuf_setlen(buf, 0);
73 else if (arg) {
74 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
75 have_message = 1;
76 } else
77 return error("switch `m' requires a value");
78 return 0;
81 static struct strategy *get_strategy(const char *name)
83 int i;
84 struct strategy *ret;
85 static struct cmdnames main_cmds, other_cmds;
86 static int loaded;
88 if (!name)
89 return NULL;
91 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
92 if (!strcmp(name, all_strategy[i].name))
93 return &all_strategy[i];
95 if (!loaded) {
96 struct cmdnames not_strategies;
97 loaded = 1;
99 memset(&not_strategies, 0, sizeof(struct cmdnames));
100 load_command_list("git-merge-", &main_cmds, &other_cmds);
101 for (i = 0; i < main_cmds.cnt; i++) {
102 int j, found = 0;
103 struct cmdname *ent = main_cmds.names[i];
104 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
105 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
106 && !all_strategy[j].name[ent->len])
107 found = 1;
108 if (!found)
109 add_cmdname(&not_strategies, ent->name, ent->len);
111 exclude_cmds(&main_cmds, &not_strategies);
113 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
114 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
115 fprintf(stderr, "Available strategies are:");
116 for (i = 0; i < main_cmds.cnt; i++)
117 fprintf(stderr, " %s", main_cmds.names[i]->name);
118 fprintf(stderr, ".\n");
119 if (other_cmds.cnt) {
120 fprintf(stderr, "Available custom strategies are:");
121 for (i = 0; i < other_cmds.cnt; i++)
122 fprintf(stderr, " %s", other_cmds.names[i]->name);
123 fprintf(stderr, ".\n");
125 exit(1);
128 ret = xcalloc(1, sizeof(struct strategy));
129 ret->name = xstrdup(name);
130 return ret;
133 static void append_strategy(struct strategy *s)
135 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
136 use_strategies[use_strategies_nr++] = s;
139 static int option_parse_strategy(const struct option *opt,
140 const char *name, int unset)
142 if (unset)
143 return 0;
145 append_strategy(get_strategy(name));
146 return 0;
149 static int option_parse_n(const struct option *opt,
150 const char *arg, int unset)
152 show_diffstat = unset;
153 return 0;
156 static struct option builtin_merge_options[] = {
157 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
158 "do not show a diffstat at the end of the merge",
159 PARSE_OPT_NOARG, option_parse_n },
160 OPT_BOOLEAN(0, "stat", &show_diffstat,
161 "show a diffstat at the end of the merge"),
162 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
163 OPT_BOOLEAN(0, "log", &option_log,
164 "add list of one-line log to merge commit message"),
165 OPT_BOOLEAN(0, "squash", &squash,
166 "create a single commit instead of doing a merge"),
167 OPT_BOOLEAN(0, "commit", &option_commit,
168 "perform a commit if the merge succeeds (default)"),
169 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
170 "allow fast-forward (default)"),
171 OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
172 "abort if fast-forward is not possible"),
173 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
174 "merge strategy to use", option_parse_strategy),
175 OPT_CALLBACK('m', "message", &merge_msg, "message",
176 "message to be used for the merge commit (if any)",
177 option_parse_message),
178 OPT__VERBOSITY(&verbosity),
179 OPT_END()
182 /* Cleans up metadata that is uninteresting after a succeeded merge. */
183 static void drop_save(void)
185 unlink(git_path("MERGE_HEAD"));
186 unlink(git_path("MERGE_MSG"));
187 unlink(git_path("MERGE_MODE"));
190 static void save_state(void)
192 int len;
193 struct child_process cp;
194 struct strbuf buffer = STRBUF_INIT;
195 const char *argv[] = {"stash", "create", NULL};
197 memset(&cp, 0, sizeof(cp));
198 cp.argv = argv;
199 cp.out = -1;
200 cp.git_cmd = 1;
202 if (start_command(&cp))
203 die("could not run stash.");
204 len = strbuf_read(&buffer, cp.out, 1024);
205 close(cp.out);
207 if (finish_command(&cp) || len < 0)
208 die("stash failed");
209 else if (!len)
210 return;
211 strbuf_setlen(&buffer, buffer.len-1);
212 if (get_sha1(buffer.buf, stash))
213 die("not a valid object: %s", buffer.buf);
216 static void reset_hard(unsigned const char *sha1, int verbose)
218 int i = 0;
219 const char *args[6];
221 args[i++] = "read-tree";
222 if (verbose)
223 args[i++] = "-v";
224 args[i++] = "--reset";
225 args[i++] = "-u";
226 args[i++] = sha1_to_hex(sha1);
227 args[i] = NULL;
229 if (run_command_v_opt(args, RUN_GIT_CMD))
230 die("read-tree failed");
233 static void restore_state(void)
235 struct strbuf sb = STRBUF_INIT;
236 const char *args[] = { "stash", "apply", NULL, NULL };
238 if (is_null_sha1(stash))
239 return;
241 reset_hard(head, 1);
243 args[2] = sha1_to_hex(stash);
246 * It is OK to ignore error here, for example when there was
247 * nothing to restore.
249 run_command_v_opt(args, RUN_GIT_CMD);
251 strbuf_release(&sb);
252 refresh_cache(REFRESH_QUIET);
255 /* This is called when no merge was necessary. */
256 static void finish_up_to_date(const char *msg)
258 if (verbosity >= 0)
259 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
260 drop_save();
263 static void squash_message(void)
265 struct rev_info rev;
266 struct commit *commit;
267 struct strbuf out = STRBUF_INIT;
268 struct commit_list *j;
269 int fd;
270 struct pretty_print_context ctx = {0};
272 printf("Squash commit -- not updating HEAD\n");
273 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
274 if (fd < 0)
275 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
277 init_revisions(&rev, NULL);
278 rev.ignore_merges = 1;
279 rev.commit_format = CMIT_FMT_MEDIUM;
281 commit = lookup_commit(head);
282 commit->object.flags |= UNINTERESTING;
283 add_pending_object(&rev, &commit->object, NULL);
285 for (j = remoteheads; j; j = j->next)
286 add_pending_object(&rev, &j->item->object, NULL);
288 setup_revisions(0, NULL, &rev, NULL);
289 if (prepare_revision_walk(&rev))
290 die("revision walk setup failed");
292 ctx.abbrev = rev.abbrev;
293 ctx.date_mode = rev.date_mode;
295 strbuf_addstr(&out, "Squashed commit of the following:\n");
296 while ((commit = get_revision(&rev)) != NULL) {
297 strbuf_addch(&out, '\n');
298 strbuf_addf(&out, "commit %s\n",
299 sha1_to_hex(commit->object.sha1));
300 pretty_print_commit(rev.commit_format, commit, &out, &ctx);
302 if (write(fd, out.buf, out.len) < 0)
303 die_errno("Writing SQUASH_MSG");
304 if (close(fd))
305 die_errno("Finishing SQUASH_MSG");
306 strbuf_release(&out);
309 static void finish(const unsigned char *new_head, const char *msg)
311 struct strbuf reflog_message = STRBUF_INIT;
313 if (!msg)
314 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
315 else {
316 if (verbosity >= 0)
317 printf("%s\n", msg);
318 strbuf_addf(&reflog_message, "%s: %s",
319 getenv("GIT_REFLOG_ACTION"), msg);
321 if (squash) {
322 squash_message();
323 } else {
324 if (verbosity >= 0 && !merge_msg.len)
325 printf("No merge message -- not updating HEAD\n");
326 else {
327 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
328 update_ref(reflog_message.buf, "HEAD",
329 new_head, head, 0,
330 DIE_ON_ERR);
332 * We ignore errors in 'gc --auto', since the
333 * user should see them.
335 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
338 if (new_head && show_diffstat) {
339 struct diff_options opts;
340 diff_setup(&opts);
341 opts.output_format |=
342 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
343 opts.detect_rename = DIFF_DETECT_RENAME;
344 if (diff_use_color_default > 0)
345 DIFF_OPT_SET(&opts, COLOR_DIFF);
346 if (diff_setup_done(&opts) < 0)
347 die("diff_setup_done failed");
348 diff_tree_sha1(head, new_head, "", &opts);
349 diffcore_std(&opts);
350 diff_flush(&opts);
353 /* Run a post-merge hook */
354 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
356 strbuf_release(&reflog_message);
359 /* Get the name for the merge commit's message. */
360 static void merge_name(const char *remote, struct strbuf *msg)
362 struct object *remote_head;
363 unsigned char branch_head[20], buf_sha[20];
364 struct strbuf buf = STRBUF_INIT;
365 struct strbuf bname = STRBUF_INIT;
366 const char *ptr;
367 char *found_ref;
368 int len, early;
370 strbuf_branchname(&bname, remote);
371 remote = bname.buf;
373 memset(branch_head, 0, sizeof(branch_head));
374 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
375 if (!remote_head)
376 die("'%s' does not point to a commit", remote);
378 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
379 if (!prefixcmp(found_ref, "refs/heads/")) {
380 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
381 sha1_to_hex(branch_head), remote);
382 goto cleanup;
384 if (!prefixcmp(found_ref, "refs/remotes/")) {
385 strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
386 sha1_to_hex(branch_head), remote);
387 goto cleanup;
391 /* See if remote matches <name>^^^.. or <name>~<number> */
392 for (len = 0, ptr = remote + strlen(remote);
393 remote < ptr && ptr[-1] == '^';
394 ptr--)
395 len++;
396 if (len)
397 early = 1;
398 else {
399 early = 0;
400 ptr = strrchr(remote, '~');
401 if (ptr) {
402 int seen_nonzero = 0;
404 len++; /* count ~ */
405 while (*++ptr && isdigit(*ptr)) {
406 seen_nonzero |= (*ptr != '0');
407 len++;
409 if (*ptr)
410 len = 0; /* not ...~<number> */
411 else if (seen_nonzero)
412 early = 1;
413 else if (len == 1)
414 early = 1; /* "name~" is "name~1"! */
417 if (len) {
418 struct strbuf truname = STRBUF_INIT;
419 strbuf_addstr(&truname, "refs/heads/");
420 strbuf_addstr(&truname, remote);
421 strbuf_setlen(&truname, truname.len - len);
422 if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
423 strbuf_addf(msg,
424 "%s\t\tbranch '%s'%s of .\n",
425 sha1_to_hex(remote_head->sha1),
426 truname.buf + 11,
427 (early ? " (early part)" : ""));
428 strbuf_release(&truname);
429 goto cleanup;
433 if (!strcmp(remote, "FETCH_HEAD") &&
434 !access(git_path("FETCH_HEAD"), R_OK)) {
435 FILE *fp;
436 struct strbuf line = STRBUF_INIT;
437 char *ptr;
439 fp = fopen(git_path("FETCH_HEAD"), "r");
440 if (!fp)
441 die_errno("could not open '%s' for reading",
442 git_path("FETCH_HEAD"));
443 strbuf_getline(&line, fp, '\n');
444 fclose(fp);
445 ptr = strstr(line.buf, "\tnot-for-merge\t");
446 if (ptr)
447 strbuf_remove(&line, ptr-line.buf+1, 13);
448 strbuf_addbuf(msg, &line);
449 strbuf_release(&line);
450 goto cleanup;
452 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
453 sha1_to_hex(remote_head->sha1), remote);
454 cleanup:
455 strbuf_release(&buf);
456 strbuf_release(&bname);
459 static int git_merge_config(const char *k, const char *v, void *cb)
461 if (branch && !prefixcmp(k, "branch.") &&
462 !prefixcmp(k + 7, branch) &&
463 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
464 const char **argv;
465 int argc;
466 char *buf;
468 buf = xstrdup(v);
469 argc = split_cmdline(buf, &argv);
470 if (argc < 0)
471 die("Bad branch.%s.mergeoptions string", branch);
472 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
473 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
474 argc++;
475 parse_options(argc, argv, NULL, builtin_merge_options,
476 builtin_merge_usage, 0);
477 free(buf);
480 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
481 show_diffstat = git_config_bool(k, v);
482 else if (!strcmp(k, "pull.twohead"))
483 return git_config_string(&pull_twohead, k, v);
484 else if (!strcmp(k, "pull.octopus"))
485 return git_config_string(&pull_octopus, k, v);
486 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
487 option_log = git_config_bool(k, v);
488 return git_diff_ui_config(k, v, cb);
491 static int read_tree_trivial(unsigned char *common, unsigned char *head,
492 unsigned char *one)
494 int i, nr_trees = 0;
495 struct tree *trees[MAX_UNPACK_TREES];
496 struct tree_desc t[MAX_UNPACK_TREES];
497 struct unpack_trees_options opts;
499 memset(&opts, 0, sizeof(opts));
500 opts.head_idx = 2;
501 opts.src_index = &the_index;
502 opts.dst_index = &the_index;
503 opts.update = 1;
504 opts.verbose_update = 1;
505 opts.trivial_merges_only = 1;
506 opts.merge = 1;
507 trees[nr_trees] = parse_tree_indirect(common);
508 if (!trees[nr_trees++])
509 return -1;
510 trees[nr_trees] = parse_tree_indirect(head);
511 if (!trees[nr_trees++])
512 return -1;
513 trees[nr_trees] = parse_tree_indirect(one);
514 if (!trees[nr_trees++])
515 return -1;
516 opts.fn = threeway_merge;
517 cache_tree_free(&active_cache_tree);
518 for (i = 0; i < nr_trees; i++) {
519 parse_tree(trees[i]);
520 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
522 if (unpack_trees(nr_trees, t, &opts))
523 return -1;
524 return 0;
527 static void write_tree_trivial(unsigned char *sha1)
529 if (write_cache_as_tree(sha1, 0, NULL))
530 die("git write-tree failed to write a tree");
533 static int try_merge_strategy(const char *strategy, struct commit_list *common,
534 const char *head_arg)
536 const char **args;
537 int i = 0, ret;
538 struct commit_list *j;
539 struct strbuf buf = STRBUF_INIT;
540 int index_fd;
541 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
543 index_fd = hold_locked_index(lock, 1);
544 refresh_cache(REFRESH_QUIET);
545 if (active_cache_changed &&
546 (write_cache(index_fd, active_cache, active_nr) ||
547 commit_locked_index(lock)))
548 return error("Unable to write index.");
549 rollback_lock_file(lock);
551 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
552 int clean;
553 struct commit *result;
554 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
555 int index_fd;
556 struct commit_list *reversed = NULL;
557 struct merge_options o;
559 if (remoteheads->next) {
560 error("Not handling anything other than two heads merge.");
561 return 2;
564 init_merge_options(&o);
565 if (!strcmp(strategy, "subtree"))
566 o.subtree_merge = 1;
568 o.branch1 = head_arg;
569 o.branch2 = remoteheads->item->util;
571 for (j = common; j; j = j->next)
572 commit_list_insert(j->item, &reversed);
574 index_fd = hold_locked_index(lock, 1);
575 clean = merge_recursive(&o, lookup_commit(head),
576 remoteheads->item, reversed, &result);
577 if (active_cache_changed &&
578 (write_cache(index_fd, active_cache, active_nr) ||
579 commit_locked_index(lock)))
580 die ("unable to write %s", get_index_file());
581 rollback_lock_file(lock);
582 return clean ? 0 : 1;
583 } else {
584 args = xmalloc((4 + commit_list_count(common) +
585 commit_list_count(remoteheads)) * sizeof(char *));
586 strbuf_addf(&buf, "merge-%s", strategy);
587 args[i++] = buf.buf;
588 for (j = common; j; j = j->next)
589 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
590 args[i++] = "--";
591 args[i++] = head_arg;
592 for (j = remoteheads; j; j = j->next)
593 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
594 args[i] = NULL;
595 ret = run_command_v_opt(args, RUN_GIT_CMD);
596 strbuf_release(&buf);
597 i = 1;
598 for (j = common; j; j = j->next)
599 free((void *)args[i++]);
600 i += 2;
601 for (j = remoteheads; j; j = j->next)
602 free((void *)args[i++]);
603 free(args);
604 discard_cache();
605 if (read_cache() < 0)
606 die("failed to read the cache");
607 return ret;
611 static void count_diff_files(struct diff_queue_struct *q,
612 struct diff_options *opt, void *data)
614 int *count = data;
616 (*count) += q->nr;
619 static int count_unmerged_entries(void)
621 const struct index_state *state = &the_index;
622 int i, ret = 0;
624 for (i = 0; i < state->cache_nr; i++)
625 if (ce_stage(state->cache[i]))
626 ret++;
628 return ret;
631 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
633 struct tree *trees[MAX_UNPACK_TREES];
634 struct unpack_trees_options opts;
635 struct tree_desc t[MAX_UNPACK_TREES];
636 int i, fd, nr_trees = 0;
637 struct dir_struct dir;
638 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
640 refresh_cache(REFRESH_QUIET);
642 fd = hold_locked_index(lock_file, 1);
644 memset(&trees, 0, sizeof(trees));
645 memset(&opts, 0, sizeof(opts));
646 memset(&t, 0, sizeof(t));
647 memset(&dir, 0, sizeof(dir));
648 dir.flags |= DIR_SHOW_IGNORED;
649 dir.exclude_per_dir = ".gitignore";
650 opts.dir = &dir;
652 opts.head_idx = 1;
653 opts.src_index = &the_index;
654 opts.dst_index = &the_index;
655 opts.update = 1;
656 opts.verbose_update = 1;
657 opts.merge = 1;
658 opts.fn = twoway_merge;
659 opts.msgs = get_porcelain_error_msgs();
661 trees[nr_trees] = parse_tree_indirect(head);
662 if (!trees[nr_trees++])
663 return -1;
664 trees[nr_trees] = parse_tree_indirect(remote);
665 if (!trees[nr_trees++])
666 return -1;
667 for (i = 0; i < nr_trees; i++) {
668 parse_tree(trees[i]);
669 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
671 if (unpack_trees(nr_trees, t, &opts))
672 return -1;
673 if (write_cache(fd, active_cache, active_nr) ||
674 commit_locked_index(lock_file))
675 die("unable to write new index file");
676 return 0;
679 static void split_merge_strategies(const char *string, struct strategy **list,
680 int *nr, int *alloc)
682 char *p, *q, *buf;
684 if (!string)
685 return;
687 buf = xstrdup(string);
688 q = buf;
689 for (;;) {
690 p = strchr(q, ' ');
691 if (!p) {
692 ALLOC_GROW(*list, *nr + 1, *alloc);
693 (*list)[(*nr)++].name = xstrdup(q);
694 free(buf);
695 return;
696 } else {
697 *p = '\0';
698 ALLOC_GROW(*list, *nr + 1, *alloc);
699 (*list)[(*nr)++].name = xstrdup(q);
700 q = ++p;
705 static void add_strategies(const char *string, unsigned attr)
707 struct strategy *list = NULL;
708 int list_alloc = 0, list_nr = 0, i;
710 memset(&list, 0, sizeof(list));
711 split_merge_strategies(string, &list, &list_nr, &list_alloc);
712 if (list) {
713 for (i = 0; i < list_nr; i++)
714 append_strategy(get_strategy(list[i].name));
715 return;
717 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
718 if (all_strategy[i].attr & attr)
719 append_strategy(&all_strategy[i]);
723 static int merge_trivial(void)
725 unsigned char result_tree[20], result_commit[20];
726 struct commit_list *parent = xmalloc(sizeof(*parent));
728 write_tree_trivial(result_tree);
729 printf("Wonderful.\n");
730 parent->item = lookup_commit(head);
731 parent->next = xmalloc(sizeof(*parent->next));
732 parent->next->item = remoteheads->item;
733 parent->next->next = NULL;
734 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
735 finish(result_commit, "In-index merge");
736 drop_save();
737 return 0;
740 static int finish_automerge(struct commit_list *common,
741 unsigned char *result_tree,
742 const char *wt_strategy)
744 struct commit_list *parents = NULL, *j;
745 struct strbuf buf = STRBUF_INIT;
746 unsigned char result_commit[20];
748 free_commit_list(common);
749 if (allow_fast_forward) {
750 parents = remoteheads;
751 commit_list_insert(lookup_commit(head), &parents);
752 parents = reduce_heads(parents);
753 } else {
754 struct commit_list **pptr = &parents;
756 pptr = &commit_list_insert(lookup_commit(head),
757 pptr)->next;
758 for (j = remoteheads; j; j = j->next)
759 pptr = &commit_list_insert(j->item, pptr)->next;
761 free_commit_list(remoteheads);
762 strbuf_addch(&merge_msg, '\n');
763 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
764 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
765 finish(result_commit, buf.buf);
766 strbuf_release(&buf);
767 drop_save();
768 return 0;
771 static int suggest_conflicts(void)
773 FILE *fp;
774 int pos;
776 fp = fopen(git_path("MERGE_MSG"), "a");
777 if (!fp)
778 die_errno("Could not open '%s' for writing",
779 git_path("MERGE_MSG"));
780 fprintf(fp, "\nConflicts:\n");
781 for (pos = 0; pos < active_nr; pos++) {
782 struct cache_entry *ce = active_cache[pos];
784 if (ce_stage(ce)) {
785 fprintf(fp, "\t%s\n", ce->name);
786 while (pos + 1 < active_nr &&
787 !strcmp(ce->name,
788 active_cache[pos + 1]->name))
789 pos++;
792 fclose(fp);
793 rerere();
794 printf("Automatic merge failed; "
795 "fix conflicts and then commit the result.\n");
796 return 1;
799 static struct commit *is_old_style_invocation(int argc, const char **argv)
801 struct commit *second_token = NULL;
802 if (argc > 2) {
803 unsigned char second_sha1[20];
805 if (get_sha1(argv[1], second_sha1))
806 return NULL;
807 second_token = lookup_commit_reference_gently(second_sha1, 0);
808 if (!second_token)
809 die("'%s' is not a commit", argv[1]);
810 if (hashcmp(second_token->object.sha1, head))
811 return NULL;
813 return second_token;
816 static int evaluate_result(void)
818 int cnt = 0;
819 struct rev_info rev;
821 /* Check how many files differ. */
822 init_revisions(&rev, "");
823 setup_revisions(0, NULL, &rev, NULL);
824 rev.diffopt.output_format |=
825 DIFF_FORMAT_CALLBACK;
826 rev.diffopt.format_callback = count_diff_files;
827 rev.diffopt.format_callback_data = &cnt;
828 run_diff_files(&rev, 0);
831 * Check how many unmerged entries are
832 * there.
834 cnt += count_unmerged_entries();
836 return cnt;
839 int cmd_merge(int argc, const char **argv, const char *prefix)
841 unsigned char result_tree[20];
842 struct strbuf buf = STRBUF_INIT;
843 const char *head_arg;
844 int flag, head_invalid = 0, i;
845 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
846 struct commit_list *common = NULL;
847 const char *best_strategy = NULL, *wt_strategy = NULL;
848 struct commit_list **remotes = &remoteheads;
850 if (file_exists(git_path("MERGE_HEAD")))
851 die("You have not concluded your merge. (MERGE_HEAD exists)");
852 if (read_cache_unmerged())
853 die("You are in the middle of a conflicted merge."
854 " (index unmerged)");
857 * Check if we are _not_ on a detached HEAD, i.e. if there is a
858 * current branch.
860 branch = resolve_ref("HEAD", head, 0, &flag);
861 if (branch && !prefixcmp(branch, "refs/heads/"))
862 branch += 11;
863 if (is_null_sha1(head))
864 head_invalid = 1;
866 git_config(git_merge_config, NULL);
868 /* for color.ui */
869 if (diff_use_color_default == -1)
870 diff_use_color_default = git_use_color_default;
872 argc = parse_options(argc, argv, prefix, builtin_merge_options,
873 builtin_merge_usage, 0);
874 if (verbosity < 0)
875 show_diffstat = 0;
877 if (squash) {
878 if (!allow_fast_forward)
879 die("You cannot combine --squash with --no-ff.");
880 option_commit = 0;
883 if (!allow_fast_forward && fast_forward_only)
884 die("You cannot combine --no-ff with --ff-only.");
886 if (!argc)
887 usage_with_options(builtin_merge_usage,
888 builtin_merge_options);
891 * This could be traditional "merge <msg> HEAD <commit>..." and
892 * the way we can tell it is to see if the second token is HEAD,
893 * but some people might have misused the interface and used a
894 * committish that is the same as HEAD there instead.
895 * Traditional format never would have "-m" so it is an
896 * additional safety measure to check for it.
899 if (!have_message && is_old_style_invocation(argc, argv)) {
900 strbuf_addstr(&merge_msg, argv[0]);
901 head_arg = argv[1];
902 argv += 2;
903 argc -= 2;
904 } else if (head_invalid) {
905 struct object *remote_head;
907 * If the merged head is a valid one there is no reason
908 * to forbid "git merge" into a branch yet to be born.
909 * We do the same for "git pull".
911 if (argc != 1)
912 die("Can merge only exactly one commit into "
913 "empty head");
914 if (squash)
915 die("Squash commit into empty head not supported yet");
916 if (!allow_fast_forward)
917 die("Non-fast-forward commit does not make sense into "
918 "an empty head");
919 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
920 if (!remote_head)
921 die("%s - not something we can merge", argv[0]);
922 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
923 DIE_ON_ERR);
924 reset_hard(remote_head->sha1, 0);
925 return 0;
926 } else {
927 struct strbuf msg = STRBUF_INIT;
929 /* We are invoked directly as the first-class UI. */
930 head_arg = "HEAD";
933 * All the rest are the commits being merged;
934 * prepare the standard merge summary message to
935 * be appended to the given message. If remote
936 * is invalid we will die later in the common
937 * codepath so we discard the error in this
938 * loop.
940 if (!have_message) {
941 for (i = 0; i < argc; i++)
942 merge_name(argv[i], &msg);
943 fmt_merge_msg(option_log, &msg, &merge_msg);
944 if (merge_msg.len)
945 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 && !fast_forward_only) {
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 if (fast_forward_only)
1094 die("Not possible to fast-forward, aborting.");
1096 /* We are going to make a new commit. */
1097 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1100 * At this point, we need a real merge. No matter what strategy
1101 * we use, it would operate on the index, possibly affecting the
1102 * working tree, and when resolved cleanly, have the desired
1103 * tree in the index -- this means that the index must be in
1104 * sync with the head commit. The strategies are responsible
1105 * to ensure this.
1107 if (use_strategies_nr != 1) {
1109 * Stash away the local changes so that we can try more
1110 * than one.
1112 save_state();
1113 } else {
1114 memcpy(stash, null_sha1, 20);
1117 for (i = 0; i < use_strategies_nr; i++) {
1118 int ret;
1119 if (i) {
1120 printf("Rewinding the tree to pristine...\n");
1121 restore_state();
1123 if (use_strategies_nr != 1)
1124 printf("Trying merge strategy %s...\n",
1125 use_strategies[i]->name);
1127 * Remember which strategy left the state in the working
1128 * tree.
1130 wt_strategy = use_strategies[i]->name;
1132 ret = try_merge_strategy(use_strategies[i]->name,
1133 common, head_arg);
1134 if (!option_commit && !ret) {
1135 merge_was_ok = 1;
1137 * This is necessary here just to avoid writing
1138 * the tree, but later we will *not* exit with
1139 * status code 1 because merge_was_ok is set.
1141 ret = 1;
1144 if (ret) {
1146 * The backend exits with 1 when conflicts are
1147 * left to be resolved, with 2 when it does not
1148 * handle the given merge at all.
1150 if (ret == 1) {
1151 int cnt = evaluate_result();
1153 if (best_cnt <= 0 || cnt <= best_cnt) {
1154 best_strategy = use_strategies[i]->name;
1155 best_cnt = cnt;
1158 if (merge_was_ok)
1159 break;
1160 else
1161 continue;
1164 /* Automerge succeeded. */
1165 write_tree_trivial(result_tree);
1166 automerge_was_ok = 1;
1167 break;
1171 * If we have a resulting tree, that means the strategy module
1172 * auto resolved the merge cleanly.
1174 if (automerge_was_ok)
1175 return finish_automerge(common, result_tree, wt_strategy);
1178 * Pick the result from the best strategy and have the user fix
1179 * it up.
1181 if (!best_strategy) {
1182 restore_state();
1183 if (use_strategies_nr > 1)
1184 fprintf(stderr,
1185 "No merge strategy handled the merge.\n");
1186 else
1187 fprintf(stderr, "Merge with strategy %s failed.\n",
1188 use_strategies[0]->name);
1189 return 2;
1190 } else if (best_strategy == wt_strategy)
1191 ; /* We already have its result in the working tree. */
1192 else {
1193 printf("Rewinding the tree to pristine...\n");
1194 restore_state();
1195 printf("Using the %s to prepare resolving by hand.\n",
1196 best_strategy);
1197 try_merge_strategy(best_strategy, common, head_arg);
1200 if (squash)
1201 finish(NULL, NULL);
1202 else {
1203 int fd;
1204 struct commit_list *j;
1206 for (j = remoteheads; j; j = j->next)
1207 strbuf_addf(&buf, "%s\n",
1208 sha1_to_hex(j->item->object.sha1));
1209 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1210 if (fd < 0)
1211 die_errno("Could not open '%s' for writing",
1212 git_path("MERGE_HEAD"));
1213 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1214 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1215 close(fd);
1216 strbuf_addch(&merge_msg, '\n');
1217 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1218 if (fd < 0)
1219 die_errno("Could not open '%s' for writing",
1220 git_path("MERGE_MSG"));
1221 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1222 merge_msg.len)
1223 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1224 close(fd);
1225 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1226 if (fd < 0)
1227 die_errno("Could not open '%s' for writing",
1228 git_path("MERGE_MODE"));
1229 strbuf_reset(&buf);
1230 if (!allow_fast_forward)
1231 strbuf_addf(&buf, "no-ff");
1232 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1233 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1234 close(fd);
1237 if (merge_was_ok) {
1238 fprintf(stderr, "Automatic merge went well; "
1239 "stopped before committing as requested\n");
1240 return 0;
1241 } else
1242 return suggest_conflicts();