gitweb: use new Git::Repo API, and add optional caching
[git/gitweb-caching.git] / builtin-merge.c
blobd6bcbec705fe5a2d278cba9cafd56415127d5afc
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"
27 #define DEFAULT_TWOHEAD (1<<0)
28 #define DEFAULT_OCTOPUS (1<<1)
29 #define NO_FAST_FORWARD (1<<2)
30 #define NO_TRIVIAL (1<<3)
32 struct strategy {
33 const char *name;
34 unsigned attr;
37 static const char * const builtin_merge_usage[] = {
38 "git-merge [options] <remote>...",
39 "git-merge [options] <msg> HEAD <remote>",
40 NULL
43 static int show_diffstat = 1, option_log, squash;
44 static int option_commit = 1, allow_fast_forward = 1;
45 static int allow_trivial = 1, have_message;
46 static struct strbuf merge_msg;
47 static struct commit_list *remoteheads;
48 static unsigned char head[20], stash[20];
49 static struct strategy **use_strategies;
50 static size_t use_strategies_nr, use_strategies_alloc;
51 static const char *branch;
53 static struct strategy all_strategy[] = {
54 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
55 { "octopus", DEFAULT_OCTOPUS },
56 { "resolve", 0 },
57 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
58 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
61 static const char *pull_twohead, *pull_octopus;
63 static int option_parse_message(const struct option *opt,
64 const char *arg, int unset)
66 struct strbuf *buf = opt->value;
68 if (unset)
69 strbuf_setlen(buf, 0);
70 else if (arg) {
71 strbuf_addf(buf, "%s\n\n", arg);
72 have_message = 1;
73 } else
74 return error("switch `m' requires a value");
75 return 0;
78 static struct strategy *get_strategy(const char *name)
80 int i;
81 struct strategy *ret;
82 static struct cmdnames main_cmds, other_cmds;
83 static int longest;
85 if (!name)
86 return NULL;
88 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
89 if (!strcmp(name, all_strategy[i].name))
90 return &all_strategy[i];
92 if (!longest) {
93 struct cmdnames not_strategies;
95 memset(&main_cmds, 0, sizeof(struct cmdnames));
96 memset(&other_cmds, 0, sizeof(struct cmdnames));
97 memset(&not_strategies, 0, sizeof(struct cmdnames));
98 longest = load_command_list("git-merge-", &main_cmds,
99 &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 = xmalloc(sizeof(struct strategy));
128 memset(ret, 0, 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_CALLBACK('s', "strategy", &use_strategies, "strategy",
172 "merge strategy to use", option_parse_strategy),
173 OPT_CALLBACK('m', "message", &merge_msg, "message",
174 "message to be used for the merge commit (if any)",
175 option_parse_message),
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"));
186 static void save_state(void)
188 int len;
189 struct child_process cp;
190 struct strbuf buffer = STRBUF_INIT;
191 const char *argv[] = {"stash", "create", NULL};
193 memset(&cp, 0, sizeof(cp));
194 cp.argv = argv;
195 cp.out = -1;
196 cp.git_cmd = 1;
198 if (start_command(&cp))
199 die("could not run stash.");
200 len = strbuf_read(&buffer, cp.out, 1024);
201 close(cp.out);
203 if (finish_command(&cp) || len < 0)
204 die("stash failed");
205 else if (!len)
206 return;
207 strbuf_setlen(&buffer, buffer.len-1);
208 if (get_sha1(buffer.buf, stash))
209 die("not a valid object: %s", buffer.buf);
212 static void reset_hard(unsigned const char *sha1, int verbose)
214 int i = 0;
215 const char *args[6];
217 args[i++] = "read-tree";
218 if (verbose)
219 args[i++] = "-v";
220 args[i++] = "--reset";
221 args[i++] = "-u";
222 args[i++] = sha1_to_hex(sha1);
223 args[i] = NULL;
225 if (run_command_v_opt(args, RUN_GIT_CMD))
226 die("read-tree failed");
229 static void restore_state(void)
231 struct strbuf sb;
232 const char *args[] = { "stash", "apply", NULL, NULL };
234 if (is_null_sha1(stash))
235 return;
237 reset_hard(head, 1);
239 strbuf_init(&sb, 0);
240 args[2] = sha1_to_hex(stash);
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 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
256 drop_save();
259 static void squash_message(void)
261 struct rev_info rev;
262 struct commit *commit;
263 struct strbuf out;
264 struct commit_list *j;
265 int fd;
267 printf("Squash commit -- not updating HEAD\n");
268 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
269 if (fd < 0)
270 die("Could not write to %s", git_path("SQUASH_MSG"));
272 init_revisions(&rev, NULL);
273 rev.ignore_merges = 1;
274 rev.commit_format = CMIT_FMT_MEDIUM;
276 commit = lookup_commit(head);
277 commit->object.flags |= UNINTERESTING;
278 add_pending_object(&rev, &commit->object, NULL);
280 for (j = remoteheads; j; j = j->next)
281 add_pending_object(&rev, &j->item->object, NULL);
283 setup_revisions(0, NULL, &rev, NULL);
284 if (prepare_revision_walk(&rev))
285 die("revision walk setup failed");
287 strbuf_init(&out, 0);
288 strbuf_addstr(&out, "Squashed commit of the following:\n");
289 while ((commit = get_revision(&rev)) != NULL) {
290 strbuf_addch(&out, '\n');
291 strbuf_addf(&out, "commit %s\n",
292 sha1_to_hex(commit->object.sha1));
293 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
294 NULL, NULL, rev.date_mode, 0);
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;
334 strbuf_init(&reflog_message, 0);
335 if (!msg)
336 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
337 else {
338 printf("%s\n", msg);
339 strbuf_addf(&reflog_message, "%s: %s",
340 getenv("GIT_REFLOG_ACTION"), msg);
342 if (squash) {
343 squash_message();
344 } else {
345 if (!merge_msg.len)
346 printf("No merge message -- not updating HEAD\n");
347 else {
348 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
349 update_ref(reflog_message.buf, "HEAD",
350 new_head, head, 0,
351 DIE_ON_ERR);
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;
386 const char *ptr;
387 int len, early;
389 memset(branch_head, 0, sizeof(branch_head));
390 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
391 if (!remote_head)
392 die("'%s' does not point to a commit", remote);
394 strbuf_init(&buf, 0);
395 strbuf_addstr(&buf, "refs/heads/");
396 strbuf_addstr(&buf, remote);
397 resolve_ref(buf.buf, branch_head, 0, 0);
399 if (!hashcmp(remote_head->sha1, branch_head)) {
400 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
401 sha1_to_hex(branch_head), remote);
402 return;
405 /* See if remote matches <name>^^^.. or <name>~<number> */
406 for (len = 0, ptr = remote + strlen(remote);
407 remote < ptr && ptr[-1] == '^';
408 ptr--)
409 len++;
410 if (len)
411 early = 1;
412 else {
413 early = 0;
414 ptr = strrchr(remote, '~');
415 if (ptr) {
416 int seen_nonzero = 0;
418 len++; /* count ~ */
419 while (*++ptr && isdigit(*ptr)) {
420 seen_nonzero |= (*ptr != '0');
421 len++;
423 if (*ptr)
424 len = 0; /* not ...~<number> */
425 else if (seen_nonzero)
426 early = 1;
427 else if (len == 1)
428 early = 1; /* "name~" is "name~1"! */
431 if (len) {
432 struct strbuf truname = STRBUF_INIT;
433 strbuf_addstr(&truname, "refs/heads/");
434 strbuf_addstr(&truname, remote);
435 strbuf_setlen(&truname, truname.len - len);
436 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
437 strbuf_addf(msg,
438 "%s\t\tbranch '%s'%s of .\n",
439 sha1_to_hex(remote_head->sha1),
440 truname.buf + 11,
441 (early ? " (early part)" : ""));
442 return;
446 if (!strcmp(remote, "FETCH_HEAD") &&
447 !access(git_path("FETCH_HEAD"), R_OK)) {
448 FILE *fp;
449 struct strbuf line;
450 char *ptr;
452 strbuf_init(&line, 0);
453 fp = fopen(git_path("FETCH_HEAD"), "r");
454 if (!fp)
455 die("could not open %s for reading: %s",
456 git_path("FETCH_HEAD"), strerror(errno));
457 strbuf_getline(&line, fp, '\n');
458 fclose(fp);
459 ptr = strstr(line.buf, "\tnot-for-merge\t");
460 if (ptr)
461 strbuf_remove(&line, ptr-line.buf+1, 13);
462 strbuf_addbuf(msg, &line);
463 strbuf_release(&line);
464 return;
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 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;
550 args = xmalloc((4 + commit_list_count(common) +
551 commit_list_count(remoteheads)) * sizeof(char *));
552 strbuf_init(&buf, 0);
553 strbuf_addf(&buf, "merge-%s", strategy);
554 args[i++] = buf.buf;
555 for (j = common; j; j = j->next)
556 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
557 args[i++] = "--";
558 args[i++] = head_arg;
559 for (j = remoteheads; j; j = j->next)
560 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
561 args[i] = NULL;
562 ret = run_command_v_opt(args, RUN_GIT_CMD);
563 strbuf_release(&buf);
564 i = 1;
565 for (j = common; j; j = j->next)
566 free((void *)args[i++]);
567 i += 2;
568 for (j = remoteheads; j; j = j->next)
569 free((void *)args[i++]);
570 free(args);
571 return -ret;
574 static void count_diff_files(struct diff_queue_struct *q,
575 struct diff_options *opt, void *data)
577 int *count = data;
579 (*count) += q->nr;
582 static int count_unmerged_entries(void)
584 const struct index_state *state = &the_index;
585 int i, ret = 0;
587 for (i = 0; i < state->cache_nr; i++)
588 if (ce_stage(state->cache[i]))
589 ret++;
591 return ret;
594 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
596 struct tree *trees[MAX_UNPACK_TREES];
597 struct unpack_trees_options opts;
598 struct tree_desc t[MAX_UNPACK_TREES];
599 int i, fd, nr_trees = 0;
600 struct dir_struct dir;
601 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
603 refresh_cache(REFRESH_QUIET);
605 fd = hold_locked_index(lock_file, 1);
607 memset(&trees, 0, sizeof(trees));
608 memset(&opts, 0, sizeof(opts));
609 memset(&t, 0, sizeof(t));
610 memset(&dir, 0, sizeof(dir));
611 dir.show_ignored = 1;
612 dir.exclude_per_dir = ".gitignore";
613 opts.dir = &dir;
615 opts.head_idx = 1;
616 opts.src_index = &the_index;
617 opts.dst_index = &the_index;
618 opts.update = 1;
619 opts.verbose_update = 1;
620 opts.merge = 1;
621 opts.fn = twoway_merge;
623 trees[nr_trees] = parse_tree_indirect(head);
624 if (!trees[nr_trees++])
625 return -1;
626 trees[nr_trees] = parse_tree_indirect(remote);
627 if (!trees[nr_trees++])
628 return -1;
629 for (i = 0; i < nr_trees; i++) {
630 parse_tree(trees[i]);
631 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
633 if (unpack_trees(nr_trees, t, &opts))
634 return -1;
635 if (write_cache(fd, active_cache, active_nr) ||
636 commit_locked_index(lock_file))
637 die("unable to write new index file");
638 return 0;
641 static void split_merge_strategies(const char *string, struct strategy **list,
642 int *nr, int *alloc)
644 char *p, *q, *buf;
646 if (!string)
647 return;
649 buf = xstrdup(string);
650 q = buf;
651 for (;;) {
652 p = strchr(q, ' ');
653 if (!p) {
654 ALLOC_GROW(*list, *nr + 1, *alloc);
655 (*list)[(*nr)++].name = xstrdup(q);
656 free(buf);
657 return;
658 } else {
659 *p = '\0';
660 ALLOC_GROW(*list, *nr + 1, *alloc);
661 (*list)[(*nr)++].name = xstrdup(q);
662 q = ++p;
667 static void add_strategies(const char *string, unsigned attr)
669 struct strategy *list = NULL;
670 int list_alloc = 0, list_nr = 0, i;
672 memset(&list, 0, sizeof(list));
673 split_merge_strategies(string, &list, &list_nr, &list_alloc);
674 if (list) {
675 for (i = 0; i < list_nr; i++)
676 append_strategy(get_strategy(list[i].name));
677 return;
679 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
680 if (all_strategy[i].attr & attr)
681 append_strategy(&all_strategy[i]);
685 static int merge_trivial(void)
687 unsigned char result_tree[20], result_commit[20];
688 struct commit_list *parent = xmalloc(sizeof(struct commit_list *));
690 write_tree_trivial(result_tree);
691 printf("Wonderful.\n");
692 parent->item = lookup_commit(head);
693 parent->next = xmalloc(sizeof(struct commit_list *));
694 parent->next->item = remoteheads->item;
695 parent->next->next = NULL;
696 commit_tree(merge_msg.buf, result_tree, parent, result_commit);
697 finish(result_commit, "In-index merge");
698 drop_save();
699 return 0;
702 static int finish_automerge(struct commit_list *common,
703 unsigned char *result_tree,
704 const char *wt_strategy)
706 struct commit_list *parents = NULL, *j;
707 struct strbuf buf = STRBUF_INIT;
708 unsigned char result_commit[20];
710 free_commit_list(common);
711 if (allow_fast_forward) {
712 parents = remoteheads;
713 commit_list_insert(lookup_commit(head), &parents);
714 parents = reduce_heads(parents);
715 } else {
716 struct commit_list **pptr = &parents;
718 pptr = &commit_list_insert(lookup_commit(head),
719 pptr)->next;
720 for (j = remoteheads; j; j = j->next)
721 pptr = &commit_list_insert(j->item, pptr)->next;
723 free_commit_list(remoteheads);
724 strbuf_addch(&merge_msg, '\n');
725 commit_tree(merge_msg.buf, result_tree, parents, result_commit);
726 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
727 finish(result_commit, buf.buf);
728 strbuf_release(&buf);
729 drop_save();
730 return 0;
733 static int suggest_conflicts(void)
735 FILE *fp;
736 int pos;
738 fp = fopen(git_path("MERGE_MSG"), "a");
739 if (!fp)
740 die("Could open %s for writing", git_path("MERGE_MSG"));
741 fprintf(fp, "\nConflicts:\n");
742 for (pos = 0; pos < active_nr; pos++) {
743 struct cache_entry *ce = active_cache[pos];
745 if (ce_stage(ce)) {
746 fprintf(fp, "\t%s\n", ce->name);
747 while (pos + 1 < active_nr &&
748 !strcmp(ce->name,
749 active_cache[pos + 1]->name))
750 pos++;
753 fclose(fp);
754 rerere();
755 printf("Automatic merge failed; "
756 "fix conflicts and then commit the result.\n");
757 return 1;
760 static struct commit *is_old_style_invocation(int argc, const char **argv)
762 struct commit *second_token = NULL;
763 if (argc > 1) {
764 unsigned char second_sha1[20];
766 if (get_sha1(argv[1], second_sha1))
767 return NULL;
768 second_token = lookup_commit_reference_gently(second_sha1, 0);
769 if (!second_token)
770 die("'%s' is not a commit", argv[1]);
771 if (hashcmp(second_token->object.sha1, head))
772 return NULL;
774 return second_token;
777 static int evaluate_result(void)
779 int cnt = 0;
780 struct rev_info rev;
782 discard_cache();
783 if (read_cache() < 0)
784 die("failed to read the cache");
786 /* Check how many files differ. */
787 init_revisions(&rev, "");
788 setup_revisions(0, NULL, &rev, NULL);
789 rev.diffopt.output_format |=
790 DIFF_FORMAT_CALLBACK;
791 rev.diffopt.format_callback = count_diff_files;
792 rev.diffopt.format_callback_data = &cnt;
793 run_diff_files(&rev, 0);
796 * Check how many unmerged entries are
797 * there.
799 cnt += count_unmerged_entries();
801 return cnt;
804 int cmd_merge(int argc, const char **argv, const char *prefix)
806 unsigned char result_tree[20];
807 struct strbuf buf;
808 const char *head_arg;
809 int flag, head_invalid = 0, i;
810 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
811 struct commit_list *common = NULL;
812 const char *best_strategy = NULL, *wt_strategy = NULL;
813 struct commit_list **remotes = &remoteheads;
815 setup_work_tree();
816 if (read_cache_unmerged())
817 die("You are in the middle of a conflicted merge.");
820 * Check if we are _not_ on a detached HEAD, i.e. if there is a
821 * current branch.
823 branch = resolve_ref("HEAD", head, 0, &flag);
824 if (branch && !prefixcmp(branch, "refs/heads/"))
825 branch += 11;
826 if (is_null_sha1(head))
827 head_invalid = 1;
829 git_config(git_merge_config, NULL);
831 /* for color.ui */
832 if (diff_use_color_default == -1)
833 diff_use_color_default = git_use_color_default;
835 argc = parse_options(argc, argv, builtin_merge_options,
836 builtin_merge_usage, 0);
838 if (squash) {
839 if (!allow_fast_forward)
840 die("You cannot combine --squash with --no-ff.");
841 option_commit = 0;
844 if (!argc)
845 usage_with_options(builtin_merge_usage,
846 builtin_merge_options);
849 * This could be traditional "merge <msg> HEAD <commit>..." and
850 * the way we can tell it is to see if the second token is HEAD,
851 * but some people might have misused the interface and used a
852 * committish that is the same as HEAD there instead.
853 * Traditional format never would have "-m" so it is an
854 * additional safety measure to check for it.
856 strbuf_init(&buf, 0);
858 if (!have_message && is_old_style_invocation(argc, argv)) {
859 strbuf_addstr(&merge_msg, argv[0]);
860 head_arg = argv[1];
861 argv += 2;
862 argc -= 2;
863 } else if (head_invalid) {
864 struct object *remote_head;
866 * If the merged head is a valid one there is no reason
867 * to forbid "git merge" into a branch yet to be born.
868 * We do the same for "git pull".
870 if (argc != 1)
871 die("Can merge only exactly one commit into "
872 "empty head");
873 if (squash)
874 die("Squash commit into empty head not supported yet");
875 if (!allow_fast_forward)
876 die("Non-fast-forward commit does not make sense into "
877 "an empty head");
878 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
879 if (!remote_head)
880 die("%s - not something we can merge", argv[0]);
881 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
882 DIE_ON_ERR);
883 reset_hard(remote_head->sha1, 0);
884 return 0;
885 } else {
886 struct strbuf msg;
888 /* We are invoked directly as the first-class UI. */
889 head_arg = "HEAD";
892 * All the rest are the commits being merged;
893 * prepare the standard merge summary message to
894 * be appended to the given message. If remote
895 * is invalid we will die later in the common
896 * codepath so we discard the error in this
897 * loop.
899 strbuf_init(&msg, 0);
900 for (i = 0; i < argc; i++)
901 merge_name(argv[i], &msg);
902 fmt_merge_msg(option_log, &msg, &merge_msg);
903 if (merge_msg.len)
904 strbuf_setlen(&merge_msg, merge_msg.len-1);
907 if (head_invalid || !argc)
908 usage_with_options(builtin_merge_usage,
909 builtin_merge_options);
911 strbuf_addstr(&buf, "merge");
912 for (i = 0; i < argc; i++)
913 strbuf_addf(&buf, " %s", argv[i]);
914 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
915 strbuf_reset(&buf);
917 for (i = 0; i < argc; i++) {
918 struct object *o;
920 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
921 if (!o)
922 die("%s - not something we can merge", argv[i]);
923 remotes = &commit_list_insert(lookup_commit(o->sha1),
924 remotes)->next;
926 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
927 setenv(buf.buf, argv[i], 1);
928 strbuf_reset(&buf);
931 if (!use_strategies) {
932 if (!remoteheads->next)
933 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
934 else
935 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
938 for (i = 0; i < use_strategies_nr; i++) {
939 if (use_strategies[i]->attr & NO_FAST_FORWARD)
940 allow_fast_forward = 0;
941 if (use_strategies[i]->attr & NO_TRIVIAL)
942 allow_trivial = 0;
945 if (!remoteheads->next)
946 common = get_merge_bases(lookup_commit(head),
947 remoteheads->item, 1);
948 else {
949 struct commit_list *list = remoteheads;
950 commit_list_insert(lookup_commit(head), &list);
951 common = get_octopus_merge_bases(list);
952 free(list);
955 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
956 DIE_ON_ERR);
958 if (!common)
959 ; /* No common ancestors found. We need a real merge. */
960 else if (!remoteheads->next && !common->next &&
961 common->item == remoteheads->item) {
963 * If head can reach all the merge then we are up to date.
964 * but first the most common case of merging one remote.
966 finish_up_to_date("Already up-to-date.");
967 return 0;
968 } else if (allow_fast_forward && !remoteheads->next &&
969 !common->next &&
970 !hashcmp(common->item->object.sha1, head)) {
971 /* Again the most common case of merging one remote. */
972 struct strbuf msg;
973 struct object *o;
974 char hex[41];
976 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
978 printf("Updating %s..%s\n",
979 hex,
980 find_unique_abbrev(remoteheads->item->object.sha1,
981 DEFAULT_ABBREV));
982 strbuf_init(&msg, 0);
983 strbuf_addstr(&msg, "Fast forward");
984 if (have_message)
985 strbuf_addstr(&msg,
986 " (no commit created; -m option ignored)");
987 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
988 0, NULL, OBJ_COMMIT);
989 if (!o)
990 return 1;
992 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
993 return 1;
995 finish(o->sha1, msg.buf);
996 drop_save();
997 return 0;
998 } else if (!remoteheads->next && common->next)
1001 * We are not doing octopus and not fast forward. Need
1002 * a real merge.
1004 else if (!remoteheads->next && !common->next && option_commit) {
1006 * We are not doing octopus, not fast forward, and have
1007 * only one common.
1009 refresh_cache(REFRESH_QUIET);
1010 if (allow_trivial) {
1011 /* See if it is really trivial. */
1012 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1013 printf("Trying really trivial in-index merge...\n");
1014 if (!read_tree_trivial(common->item->object.sha1,
1015 head, remoteheads->item->object.sha1))
1016 return merge_trivial();
1017 printf("Nope.\n");
1019 } else {
1021 * An octopus. If we can reach all the remote we are up
1022 * to date.
1024 int up_to_date = 1;
1025 struct commit_list *j;
1027 for (j = remoteheads; j; j = j->next) {
1028 struct commit_list *common_one;
1031 * Here we *have* to calculate the individual
1032 * merge_bases again, otherwise "git merge HEAD^
1033 * HEAD^^" would be missed.
1035 common_one = get_merge_bases(lookup_commit(head),
1036 j->item, 1);
1037 if (hashcmp(common_one->item->object.sha1,
1038 j->item->object.sha1)) {
1039 up_to_date = 0;
1040 break;
1043 if (up_to_date) {
1044 finish_up_to_date("Already up-to-date. Yeeah!");
1045 return 0;
1049 /* We are going to make a new commit. */
1050 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1053 * At this point, we need a real merge. No matter what strategy
1054 * we use, it would operate on the index, possibly affecting the
1055 * working tree, and when resolved cleanly, have the desired
1056 * tree in the index -- this means that the index must be in
1057 * sync with the head commit. The strategies are responsible
1058 * to ensure this.
1060 if (use_strategies_nr != 1) {
1062 * Stash away the local changes so that we can try more
1063 * than one.
1065 save_state();
1066 } else {
1067 memcpy(stash, null_sha1, 20);
1070 for (i = 0; i < use_strategies_nr; i++) {
1071 int ret;
1072 if (i) {
1073 printf("Rewinding the tree to pristine...\n");
1074 restore_state();
1076 if (use_strategies_nr != 1)
1077 printf("Trying merge strategy %s...\n",
1078 use_strategies[i]->name);
1080 * Remember which strategy left the state in the working
1081 * tree.
1083 wt_strategy = use_strategies[i]->name;
1085 ret = try_merge_strategy(use_strategies[i]->name,
1086 common, head_arg);
1087 if (!option_commit && !ret) {
1088 merge_was_ok = 1;
1090 * This is necessary here just to avoid writing
1091 * the tree, but later we will *not* exit with
1092 * status code 1 because merge_was_ok is set.
1094 ret = 1;
1097 if (ret) {
1099 * The backend exits with 1 when conflicts are
1100 * left to be resolved, with 2 when it does not
1101 * handle the given merge at all.
1103 if (ret == 1) {
1104 int cnt = evaluate_result();
1106 if (best_cnt <= 0 || cnt <= best_cnt) {
1107 best_strategy = use_strategies[i]->name;
1108 best_cnt = cnt;
1111 if (merge_was_ok)
1112 break;
1113 else
1114 continue;
1117 /* Automerge succeeded. */
1118 discard_cache();
1119 write_tree_trivial(result_tree);
1120 automerge_was_ok = 1;
1121 break;
1125 * If we have a resulting tree, that means the strategy module
1126 * auto resolved the merge cleanly.
1128 if (automerge_was_ok)
1129 return finish_automerge(common, result_tree, wt_strategy);
1132 * Pick the result from the best strategy and have the user fix
1133 * it up.
1135 if (!best_strategy) {
1136 restore_state();
1137 if (use_strategies_nr > 1)
1138 fprintf(stderr,
1139 "No merge strategy handled the merge.\n");
1140 else
1141 fprintf(stderr, "Merge with strategy %s failed.\n",
1142 use_strategies[0]->name);
1143 return 2;
1144 } else if (best_strategy == wt_strategy)
1145 ; /* We already have its result in the working tree. */
1146 else {
1147 printf("Rewinding the tree to pristine...\n");
1148 restore_state();
1149 printf("Using the %s to prepare resolving by hand.\n",
1150 best_strategy);
1151 try_merge_strategy(best_strategy, common, head_arg);
1154 if (squash)
1155 finish(NULL, NULL);
1156 else {
1157 int fd;
1158 struct commit_list *j;
1160 for (j = remoteheads; j; j = j->next)
1161 strbuf_addf(&buf, "%s\n",
1162 sha1_to_hex(j->item->object.sha1));
1163 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1164 if (fd < 0)
1165 die("Could open %s for writing",
1166 git_path("MERGE_HEAD"));
1167 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1168 die("Could not write to %s", git_path("MERGE_HEAD"));
1169 close(fd);
1170 strbuf_addch(&merge_msg, '\n');
1171 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1172 if (fd < 0)
1173 die("Could open %s for writing", git_path("MERGE_MSG"));
1174 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1175 merge_msg.len)
1176 die("Could not write to %s", git_path("MERGE_MSG"));
1177 close(fd);
1180 if (merge_was_ok) {
1181 fprintf(stderr, "Automatic merge went well; "
1182 "stopped before committing as requested\n");
1183 return 0;
1184 } else
1185 return suggest_conflicts();