129b4e62dd3bc3662f8f076e39c90b109f4bd669
[git/git.git] / builtin-merge.c
1 /*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
6 * Based on git-merge.sh by Junio C Hamano.
7 */
8
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
26 #define DEFAULT_TWOHEAD (1<<0)
27 #define DEFAULT_OCTOPUS (1<<1)
28 #define NO_FAST_FORWARD (1<<2)
29 #define NO_TRIVIAL (1<<3)
30
31 struct strategy {
32 const char *name;
33 unsigned attr;
34 };
35
36 static const char * const builtin_merge_usage[] = {
37 "git-merge [options] <remote>...",
38 "git-merge [options] <msg> HEAD <remote>",
39 NULL
40 };
41
42 static int show_diffstat = 1, option_log, squash;
43 static int option_commit = 1, allow_fast_forward = 1;
44 static int allow_trivial = 1, have_message;
45 static struct strbuf merge_msg;
46 static struct commit_list *remoteheads;
47 static unsigned char head[20], stash[20];
48 static struct strategy **use_strategies;
49 static size_t use_strategies_nr, use_strategies_alloc;
50 static const char *branch;
51
52 static struct strategy all_strategy[] = {
53 { "recur", NO_TRIVIAL },
54 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
55 { "octopus", DEFAULT_OCTOPUS },
56 { "resolve", 0 },
57 { "stupid", 0 },
58 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
59 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
60 };
61
62 static const char *pull_twohead, *pull_octopus;
63
64 static int option_parse_message(const struct option *opt,
65 const char *arg, int unset)
66 {
67 struct strbuf *buf = opt->value;
68
69 if (unset)
70 strbuf_setlen(buf, 0);
71 else {
72 strbuf_addf(buf, "%s\n\n", arg);
73 have_message = 1;
74 }
75 return 0;
76 }
77
78 static struct strategy *get_strategy(const char *name)
79 {
80 int i;
81
82 if (!name)
83 return NULL;
84
85 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
86 if (!strcmp(name, all_strategy[i].name))
87 return &all_strategy[i];
88 return NULL;
89 }
90
91 static void append_strategy(struct strategy *s)
92 {
93 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
94 use_strategies[use_strategies_nr++] = s;
95 }
96
97 static int option_parse_strategy(const struct option *opt,
98 const char *name, int unset)
99 {
100 int i;
101 struct strategy *s;
102
103 if (unset)
104 return 0;
105
106 s = get_strategy(name);
107
108 if (s)
109 append_strategy(s);
110 else {
111 struct strbuf err;
112 strbuf_init(&err, 0);
113 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
114 strbuf_addf(&err, " %s", all_strategy[i].name);
115 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
116 fprintf(stderr, "Available strategies are:%s.\n", err.buf);
117 exit(1);
118 }
119 return 0;
120 }
121
122 static int option_parse_n(const struct option *opt,
123 const char *arg, int unset)
124 {
125 show_diffstat = unset;
126 return 0;
127 }
128
129 static struct option builtin_merge_options[] = {
130 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
131 "do not show a diffstat at the end of the merge",
132 PARSE_OPT_NOARG, option_parse_n },
133 OPT_BOOLEAN(0, "stat", &show_diffstat,
134 "show a diffstat at the end of the merge"),
135 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
136 OPT_BOOLEAN(0, "log", &option_log,
137 "add list of one-line log to merge commit message"),
138 OPT_BOOLEAN(0, "squash", &squash,
139 "create a single commit instead of doing a merge"),
140 OPT_BOOLEAN(0, "commit", &option_commit,
141 "perform a commit if the merge succeeds (default)"),
142 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
143 "allow fast forward (default)"),
144 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
145 "merge strategy to use", option_parse_strategy),
146 OPT_CALLBACK('m', "message", &merge_msg, "message",
147 "message to be used for the merge commit (if any)",
148 option_parse_message),
149 OPT_END()
150 };
151
152 /* Cleans up metadata that is uninteresting after a succeeded merge. */
153 static void drop_save(void)
154 {
155 unlink(git_path("MERGE_HEAD"));
156 unlink(git_path("MERGE_MSG"));
157 }
158
159 static void save_state(void)
160 {
161 int len;
162 struct child_process cp;
163 struct strbuf buffer = STRBUF_INIT;
164 const char *argv[] = {"stash", "create", NULL};
165
166 memset(&cp, 0, sizeof(cp));
167 cp.argv = argv;
168 cp.out = -1;
169 cp.git_cmd = 1;
170
171 if (start_command(&cp))
172 die("could not run stash.");
173 len = strbuf_read(&buffer, cp.out, 1024);
174 close(cp.out);
175
176 if (finish_command(&cp) || len < 0)
177 die("stash failed");
178 else if (!len)
179 return;
180 strbuf_setlen(&buffer, buffer.len-1);
181 if (get_sha1(buffer.buf, stash))
182 die("not a valid object: %s", buffer.buf);
183 }
184
185 static void reset_hard(unsigned const char *sha1, int verbose)
186 {
187 int i = 0;
188 const char *args[6];
189
190 args[i++] = "read-tree";
191 if (verbose)
192 args[i++] = "-v";
193 args[i++] = "--reset";
194 args[i++] = "-u";
195 args[i++] = sha1_to_hex(sha1);
196 args[i] = NULL;
197
198 if (run_command_v_opt(args, RUN_GIT_CMD))
199 die("read-tree failed");
200 }
201
202 static void restore_state(void)
203 {
204 struct strbuf sb;
205 const char *args[] = { "stash", "apply", NULL, NULL };
206
207 if (is_null_sha1(stash))
208 return;
209
210 reset_hard(head, 1);
211
212 strbuf_init(&sb, 0);
213 args[2] = sha1_to_hex(stash);
214
215 /*
216 * It is OK to ignore error here, for example when there was
217 * nothing to restore.
218 */
219 run_command_v_opt(args, RUN_GIT_CMD);
220
221 strbuf_release(&sb);
222 refresh_cache(REFRESH_QUIET);
223 }
224
225 /* This is called when no merge was necessary. */
226 static void finish_up_to_date(const char *msg)
227 {
228 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
229 drop_save();
230 }
231
232 static void squash_message(void)
233 {
234 struct rev_info rev;
235 struct commit *commit;
236 struct strbuf out;
237 struct commit_list *j;
238 int fd;
239
240 printf("Squash commit -- not updating HEAD\n");
241 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
242 if (fd < 0)
243 die("Could not write to %s", git_path("SQUASH_MSG"));
244
245 init_revisions(&rev, NULL);
246 rev.ignore_merges = 1;
247 rev.commit_format = CMIT_FMT_MEDIUM;
248
249 commit = lookup_commit(head);
250 commit->object.flags |= UNINTERESTING;
251 add_pending_object(&rev, &commit->object, NULL);
252
253 for (j = remoteheads; j; j = j->next)
254 add_pending_object(&rev, &j->item->object, NULL);
255
256 setup_revisions(0, NULL, &rev, NULL);
257 if (prepare_revision_walk(&rev))
258 die("revision walk setup failed");
259
260 strbuf_init(&out, 0);
261 strbuf_addstr(&out, "Squashed commit of the following:\n");
262 while ((commit = get_revision(&rev)) != NULL) {
263 strbuf_addch(&out, '\n');
264 strbuf_addf(&out, "commit %s\n",
265 sha1_to_hex(commit->object.sha1));
266 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
267 NULL, NULL, rev.date_mode, 0);
268 }
269 write(fd, out.buf, out.len);
270 close(fd);
271 strbuf_release(&out);
272 }
273
274 static int run_hook(const char *name)
275 {
276 struct child_process hook;
277 const char *argv[3], *env[2];
278 char index[PATH_MAX];
279
280 argv[0] = git_path("hooks/%s", name);
281 if (access(argv[0], X_OK) < 0)
282 return 0;
283
284 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
285 env[0] = index;
286 env[1] = NULL;
287
288 if (squash)
289 argv[1] = "1";
290 else
291 argv[1] = "0";
292 argv[2] = NULL;
293
294 memset(&hook, 0, sizeof(hook));
295 hook.argv = argv;
296 hook.no_stdin = 1;
297 hook.stdout_to_stderr = 1;
298 hook.env = env;
299
300 return run_command(&hook);
301 }
302
303 static void finish(const unsigned char *new_head, const char *msg)
304 {
305 struct strbuf reflog_message;
306
307 strbuf_init(&reflog_message, 0);
308 if (!msg)
309 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
310 else {
311 printf("%s\n", msg);
312 strbuf_addf(&reflog_message, "%s: %s",
313 getenv("GIT_REFLOG_ACTION"), msg);
314 }
315 if (squash) {
316 squash_message();
317 } else {
318 if (!merge_msg.len)
319 printf("No merge message -- not updating HEAD\n");
320 else {
321 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
322 update_ref(reflog_message.buf, "HEAD",
323 new_head, head, 0,
324 DIE_ON_ERR);
325 /*
326 * We ignore errors in 'gc --auto', since the
327 * user should see them.
328 */
329 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
330 }
331 }
332 if (new_head && show_diffstat) {
333 struct diff_options opts;
334 diff_setup(&opts);
335 opts.output_format |=
336 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
337 opts.detect_rename = DIFF_DETECT_RENAME;
338 if (diff_use_color_default > 0)
339 DIFF_OPT_SET(&opts, COLOR_DIFF);
340 if (diff_setup_done(&opts) < 0)
341 die("diff_setup_done failed");
342 diff_tree_sha1(head, new_head, "", &opts);
343 diffcore_std(&opts);
344 diff_flush(&opts);
345 }
346
347 /* Run a post-merge hook */
348 run_hook("post-merge");
349
350 strbuf_release(&reflog_message);
351 }
352
353 /* Get the name for the merge commit's message. */
354 static void merge_name(const char *remote, struct strbuf *msg)
355 {
356 struct object *remote_head;
357 unsigned char branch_head[20], buf_sha[20];
358 struct strbuf buf;
359 const char *ptr;
360 int len, early;
361
362 memset(branch_head, 0, sizeof(branch_head));
363 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
364 if (!remote_head)
365 die("'%s' does not point to a commit", remote);
366
367 strbuf_init(&buf, 0);
368 strbuf_addstr(&buf, "refs/heads/");
369 strbuf_addstr(&buf, remote);
370 resolve_ref(buf.buf, branch_head, 0, 0);
371
372 if (!hashcmp(remote_head->sha1, branch_head)) {
373 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
374 sha1_to_hex(branch_head), remote);
375 return;
376 }
377
378 /* See if remote matches <name>^^^.. or <name>~<number> */
379 for (len = 0, ptr = remote + strlen(remote);
380 remote < ptr && ptr[-1] == '^';
381 ptr--)
382 len++;
383 if (len)
384 early = 1;
385 else {
386 early = 0;
387 ptr = strrchr(remote, '~');
388 if (ptr) {
389 int seen_nonzero = 0;
390
391 len++; /* count ~ */
392 while (*++ptr && isdigit(*ptr)) {
393 seen_nonzero |= (*ptr != '0');
394 len++;
395 }
396 if (*ptr)
397 len = 0; /* not ...~<number> */
398 else if (seen_nonzero)
399 early = 1;
400 else if (len == 1)
401 early = 1; /* "name~" is "name~1"! */
402 }
403 }
404 if (len) {
405 struct strbuf truname = STRBUF_INIT;
406 strbuf_addstr(&truname, "refs/heads/");
407 strbuf_addstr(&truname, remote);
408 strbuf_setlen(&truname, len+11);
409 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
410 strbuf_addf(msg,
411 "%s\t\tbranch '%s'%s of .\n",
412 sha1_to_hex(remote_head->sha1),
413 truname.buf,
414 (early ? " (early part)" : ""));
415 return;
416 }
417 }
418
419 if (!strcmp(remote, "FETCH_HEAD") &&
420 !access(git_path("FETCH_HEAD"), R_OK)) {
421 FILE *fp;
422 struct strbuf line;
423 char *ptr;
424
425 strbuf_init(&line, 0);
426 fp = fopen(git_path("FETCH_HEAD"), "r");
427 if (!fp)
428 die("could not open %s for reading: %s",
429 git_path("FETCH_HEAD"), strerror(errno));
430 strbuf_getline(&line, fp, '\n');
431 fclose(fp);
432 ptr = strstr(line.buf, "\tnot-for-merge\t");
433 if (ptr)
434 strbuf_remove(&line, ptr-line.buf+1, 13);
435 strbuf_addbuf(msg, &line);
436 strbuf_release(&line);
437 return;
438 }
439 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
440 sha1_to_hex(remote_head->sha1), remote);
441 }
442
443 int git_merge_config(const char *k, const char *v, void *cb)
444 {
445 if (branch && !prefixcmp(k, "branch.") &&
446 !prefixcmp(k + 7, branch) &&
447 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
448 const char **argv;
449 int argc;
450 char *buf;
451
452 buf = xstrdup(v);
453 argc = split_cmdline(buf, &argv);
454 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
455 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
456 argc++;
457 parse_options(argc, argv, builtin_merge_options,
458 builtin_merge_usage, 0);
459 free(buf);
460 }
461
462 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
463 show_diffstat = git_config_bool(k, v);
464 else if (!strcmp(k, "pull.twohead"))
465 return git_config_string(&pull_twohead, k, v);
466 else if (!strcmp(k, "pull.octopus"))
467 return git_config_string(&pull_octopus, k, v);
468 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
469 option_log = git_config_bool(k, v);
470 return git_diff_ui_config(k, v, cb);
471 }
472
473 static int read_tree_trivial(unsigned char *common, unsigned char *head,
474 unsigned char *one)
475 {
476 int i, nr_trees = 0;
477 struct tree *trees[MAX_UNPACK_TREES];
478 struct tree_desc t[MAX_UNPACK_TREES];
479 struct unpack_trees_options opts;
480
481 memset(&opts, 0, sizeof(opts));
482 opts.head_idx = 2;
483 opts.src_index = &the_index;
484 opts.dst_index = &the_index;
485 opts.update = 1;
486 opts.verbose_update = 1;
487 opts.trivial_merges_only = 1;
488 opts.merge = 1;
489 trees[nr_trees] = parse_tree_indirect(common);
490 if (!trees[nr_trees++])
491 return -1;
492 trees[nr_trees] = parse_tree_indirect(head);
493 if (!trees[nr_trees++])
494 return -1;
495 trees[nr_trees] = parse_tree_indirect(one);
496 if (!trees[nr_trees++])
497 return -1;
498 opts.fn = threeway_merge;
499 cache_tree_free(&active_cache_tree);
500 for (i = 0; i < nr_trees; i++) {
501 parse_tree(trees[i]);
502 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
503 }
504 if (unpack_trees(nr_trees, t, &opts))
505 return -1;
506 return 0;
507 }
508
509 static void write_tree_trivial(unsigned char *sha1)
510 {
511 if (write_cache_as_tree(sha1, 0, NULL))
512 die("git write-tree failed to write a tree");
513 }
514
515 static int try_merge_strategy(const char *strategy, struct commit_list *common,
516 const char *head_arg)
517 {
518 const char **args;
519 int i = 0, ret;
520 struct commit_list *j;
521 struct strbuf buf;
522
523 args = xmalloc((4 + commit_list_count(common) +
524 commit_list_count(remoteheads)) * sizeof(char *));
525 strbuf_init(&buf, 0);
526 strbuf_addf(&buf, "merge-%s", strategy);
527 args[i++] = buf.buf;
528 for (j = common; j; j = j->next)
529 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
530 args[i++] = "--";
531 args[i++] = head_arg;
532 for (j = remoteheads; j; j = j->next)
533 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
534 args[i] = NULL;
535 ret = run_command_v_opt(args, RUN_GIT_CMD);
536 strbuf_release(&buf);
537 i = 1;
538 for (j = common; j; j = j->next)
539 free((void *)args[i++]);
540 i += 2;
541 for (j = remoteheads; j; j = j->next)
542 free((void *)args[i++]);
543 free(args);
544 return -ret;
545 }
546
547 static void count_diff_files(struct diff_queue_struct *q,
548 struct diff_options *opt, void *data)
549 {
550 int *count = data;
551
552 (*count) += q->nr;
553 }
554
555 static int count_unmerged_entries(void)
556 {
557 const struct index_state *state = &the_index;
558 int i, ret = 0;
559
560 for (i = 0; i < state->cache_nr; i++)
561 if (ce_stage(state->cache[i]))
562 ret++;
563
564 return ret;
565 }
566
567 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
568 {
569 struct tree *trees[MAX_UNPACK_TREES];
570 struct unpack_trees_options opts;
571 struct tree_desc t[MAX_UNPACK_TREES];
572 int i, fd, nr_trees = 0;
573 struct dir_struct dir;
574 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
575
576 if (read_cache_unmerged())
577 die("you need to resolve your current index first");
578
579 fd = hold_locked_index(lock_file, 1);
580
581 memset(&trees, 0, sizeof(trees));
582 memset(&opts, 0, sizeof(opts));
583 memset(&t, 0, sizeof(t));
584 dir.show_ignored = 1;
585 dir.exclude_per_dir = ".gitignore";
586 opts.dir = &dir;
587
588 opts.head_idx = 1;
589 opts.src_index = &the_index;
590 opts.dst_index = &the_index;
591 opts.update = 1;
592 opts.verbose_update = 1;
593 opts.merge = 1;
594 opts.fn = twoway_merge;
595
596 trees[nr_trees] = parse_tree_indirect(head);
597 if (!trees[nr_trees++])
598 return -1;
599 trees[nr_trees] = parse_tree_indirect(remote);
600 if (!trees[nr_trees++])
601 return -1;
602 for (i = 0; i < nr_trees; i++) {
603 parse_tree(trees[i]);
604 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
605 }
606 if (unpack_trees(nr_trees, t, &opts))
607 return -1;
608 if (write_cache(fd, active_cache, active_nr) ||
609 commit_locked_index(lock_file))
610 die("unable to write new index file");
611 return 0;
612 }
613
614 static void split_merge_strategies(const char *string, struct strategy **list,
615 int *nr, int *alloc)
616 {
617 char *p, *q, *buf;
618
619 if (!string)
620 return;
621
622 buf = xstrdup(string);
623 q = buf;
624 for (;;) {
625 p = strchr(q, ' ');
626 if (!p) {
627 ALLOC_GROW(*list, *nr + 1, *alloc);
628 (*list)[(*nr)++].name = xstrdup(q);
629 free(buf);
630 return;
631 } else {
632 *p = '\0';
633 ALLOC_GROW(*list, *nr + 1, *alloc);
634 (*list)[(*nr)++].name = xstrdup(q);
635 q = ++p;
636 }
637 }
638 }
639
640 static void add_strategies(const char *string, unsigned attr)
641 {
642 struct strategy *list = NULL;
643 int list_alloc = 0, list_nr = 0, i;
644
645 memset(&list, 0, sizeof(list));
646 split_merge_strategies(string, &list, &list_nr, &list_alloc);
647 if (list != NULL) {
648 for (i = 0; i < list_nr; i++) {
649 struct strategy *s;
650
651 s = get_strategy(list[i].name);
652 if (s)
653 append_strategy(s);
654 }
655 return;
656 }
657 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
658 if (all_strategy[i].attr & attr)
659 append_strategy(&all_strategy[i]);
660
661 }
662
663 static int merge_trivial(void)
664 {
665 unsigned char result_tree[20], result_commit[20];
666 struct commit_list parent;
667
668 write_tree_trivial(result_tree);
669 printf("Wonderful.\n");
670 parent.item = remoteheads->item;
671 parent.next = NULL;
672 commit_tree(merge_msg.buf, result_tree, &parent, result_commit);
673 finish(result_commit, "In-index merge");
674 drop_save();
675 return 0;
676 }
677
678 static int finish_automerge(struct commit_list *common,
679 unsigned char *result_tree,
680 const char *wt_strategy)
681 {
682 struct commit_list *parents = NULL, *j;
683 struct strbuf buf = STRBUF_INIT;
684 unsigned char result_commit[20];
685
686 free_commit_list(common);
687 if (allow_fast_forward) {
688 parents = remoteheads;
689 commit_list_insert(lookup_commit(head), &parents);
690 parents = reduce_heads(parents);
691 } else {
692 struct commit_list **pptr = &parents;
693
694 pptr = &commit_list_insert(lookup_commit(head),
695 pptr)->next;
696 for (j = remoteheads; j; j = j->next)
697 pptr = &commit_list_insert(j->item, pptr)->next;
698 }
699 free_commit_list(remoteheads);
700 strbuf_addch(&merge_msg, '\n');
701 commit_tree(merge_msg.buf, result_tree, parents, result_commit);
702 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
703 finish(result_commit, buf.buf);
704 strbuf_release(&buf);
705 drop_save();
706 return 0;
707 }
708
709 static int suggest_conflicts(void)
710 {
711 FILE *fp;
712 int pos;
713
714 fp = fopen(git_path("MERGE_MSG"), "a");
715 if (!fp)
716 die("Could open %s for writing", git_path("MERGE_MSG"));
717 fprintf(fp, "\nConflicts:\n");
718 for (pos = 0; pos < active_nr; pos++) {
719 struct cache_entry *ce = active_cache[pos];
720
721 if (ce_stage(ce)) {
722 fprintf(fp, "\t%s\n", ce->name);
723 while (pos + 1 < active_nr &&
724 !strcmp(ce->name,
725 active_cache[pos + 1]->name))
726 pos++;
727 }
728 }
729 fclose(fp);
730 rerere();
731 printf("Automatic merge failed; "
732 "fix conflicts and then commit the result.\n");
733 return 1;
734 }
735
736 static struct commit *is_old_style_invocation(int argc, const char **argv)
737 {
738 struct commit *second_token = NULL;
739 if (argc > 1) {
740 unsigned char second_sha1[20];
741
742 if (get_sha1(argv[1], second_sha1))
743 return NULL;
744 second_token = lookup_commit_reference_gently(second_sha1, 0);
745 if (!second_token)
746 die("'%s' is not a commit", argv[1]);
747 if (hashcmp(second_token->object.sha1, head))
748 return NULL;
749 }
750 return second_token;
751 }
752
753 static int evaluate_result(void)
754 {
755 int cnt = 0;
756 struct rev_info rev;
757
758 if (read_cache() < 0)
759 die("failed to read the cache");
760
761 /* Check how many files differ. */
762 init_revisions(&rev, "");
763 setup_revisions(0, NULL, &rev, NULL);
764 rev.diffopt.output_format |=
765 DIFF_FORMAT_CALLBACK;
766 rev.diffopt.format_callback = count_diff_files;
767 rev.diffopt.format_callback_data = &cnt;
768 run_diff_files(&rev, 0);
769
770 /*
771 * Check how many unmerged entries are
772 * there.
773 */
774 cnt += count_unmerged_entries();
775
776 return cnt;
777 }
778
779 int cmd_merge(int argc, const char **argv, const char *prefix)
780 {
781 unsigned char result_tree[20];
782 struct strbuf buf;
783 const char *head_arg;
784 int flag, head_invalid = 0, i;
785 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
786 struct commit_list *common = NULL;
787 const char *best_strategy = NULL, *wt_strategy = NULL;
788 struct commit_list **remotes = &remoteheads;
789
790 setup_work_tree();
791 if (unmerged_cache())
792 die("You are in the middle of a conflicted merge.");
793
794 /*
795 * Check if we are _not_ on a detached HEAD, i.e. if there is a
796 * current branch.
797 */
798 branch = resolve_ref("HEAD", head, 0, &flag);
799 if (branch && !prefixcmp(branch, "refs/heads/"))
800 branch += 11;
801 if (is_null_sha1(head))
802 head_invalid = 1;
803
804 git_config(git_merge_config, NULL);
805
806 /* for color.ui */
807 if (diff_use_color_default == -1)
808 diff_use_color_default = git_use_color_default;
809
810 argc = parse_options(argc, argv, builtin_merge_options,
811 builtin_merge_usage, 0);
812
813 if (squash) {
814 if (!allow_fast_forward)
815 die("You cannot combine --squash with --no-ff.");
816 option_commit = 0;
817 }
818
819 if (!argc)
820 usage_with_options(builtin_merge_usage,
821 builtin_merge_options);
822
823 /*
824 * This could be traditional "merge <msg> HEAD <commit>..." and
825 * the way we can tell it is to see if the second token is HEAD,
826 * but some people might have misused the interface and used a
827 * committish that is the same as HEAD there instead.
828 * Traditional format never would have "-m" so it is an
829 * additional safety measure to check for it.
830 */
831 strbuf_init(&buf, 0);
832
833 if (!have_message && is_old_style_invocation(argc, argv)) {
834 strbuf_addstr(&merge_msg, argv[0]);
835 head_arg = argv[1];
836 argv += 2;
837 argc -= 2;
838 } else if (head_invalid) {
839 struct object *remote_head;
840 /*
841 * If the merged head is a valid one there is no reason
842 * to forbid "git merge" into a branch yet to be born.
843 * We do the same for "git pull".
844 */
845 if (argc != 1)
846 die("Can merge only exactly one commit into "
847 "empty head");
848 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
849 if (!remote_head)
850 die("%s - not something we can merge", argv[0]);
851 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
852 DIE_ON_ERR);
853 reset_hard(remote_head->sha1, 0);
854 return 0;
855 } else {
856 struct strbuf msg;
857
858 /* We are invoked directly as the first-class UI. */
859 head_arg = "HEAD";
860
861 /*
862 * All the rest are the commits being merged;
863 * prepare the standard merge summary message to
864 * be appended to the given message. If remote
865 * is invalid we will die later in the common
866 * codepath so we discard the error in this
867 * loop.
868 */
869 strbuf_init(&msg, 0);
870 for (i = 0; i < argc; i++)
871 merge_name(argv[i], &msg);
872 fmt_merge_msg(option_log, &msg, &merge_msg);
873 if (merge_msg.len)
874 strbuf_setlen(&merge_msg, merge_msg.len-1);
875 }
876
877 if (head_invalid || !argc)
878 usage_with_options(builtin_merge_usage,
879 builtin_merge_options);
880
881 strbuf_addstr(&buf, "merge");
882 for (i = 0; i < argc; i++)
883 strbuf_addf(&buf, " %s", argv[i]);
884 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
885 strbuf_reset(&buf);
886
887 for (i = 0; i < argc; i++) {
888 struct object *o;
889
890 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
891 if (!o)
892 die("%s - not something we can merge", argv[i]);
893 remotes = &commit_list_insert(lookup_commit(o->sha1),
894 remotes)->next;
895
896 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
897 setenv(buf.buf, argv[i], 1);
898 strbuf_reset(&buf);
899 }
900
901 if (!use_strategies) {
902 if (!remoteheads->next)
903 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
904 else
905 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
906 }
907
908 for (i = 0; i < use_strategies_nr; i++) {
909 if (use_strategies[i]->attr & NO_FAST_FORWARD)
910 allow_fast_forward = 0;
911 if (use_strategies[i]->attr & NO_TRIVIAL)
912 allow_trivial = 0;
913 }
914
915 if (!remoteheads->next)
916 common = get_merge_bases(lookup_commit(head),
917 remoteheads->item, 1);
918 else {
919 struct commit_list *list = remoteheads;
920 commit_list_insert(lookup_commit(head), &list);
921 common = get_octopus_merge_bases(list);
922 free(list);
923 }
924
925 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
926 DIE_ON_ERR);
927
928 if (!common)
929 ; /* No common ancestors found. We need a real merge. */
930 else if (!remoteheads->next && !common->next &&
931 common->item == remoteheads->item) {
932 /*
933 * If head can reach all the merge then we are up to date.
934 * but first the most common case of merging one remote.
935 */
936 finish_up_to_date("Already up-to-date.");
937 return 0;
938 } else if (allow_fast_forward && !remoteheads->next &&
939 !common->next &&
940 !hashcmp(common->item->object.sha1, head)) {
941 /* Again the most common case of merging one remote. */
942 struct strbuf msg;
943 struct object *o;
944 char hex[41];
945
946 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
947
948 printf("Updating %s..%s\n",
949 hex,
950 find_unique_abbrev(remoteheads->item->object.sha1,
951 DEFAULT_ABBREV));
952 refresh_cache(REFRESH_QUIET);
953 strbuf_init(&msg, 0);
954 strbuf_addstr(&msg, "Fast forward");
955 if (have_message)
956 strbuf_addstr(&msg,
957 " (no commit created; -m option ignored)");
958 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
959 0, NULL, OBJ_COMMIT);
960 if (!o)
961 return 1;
962
963 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
964 return 1;
965
966 finish(o->sha1, msg.buf);
967 drop_save();
968 return 0;
969 } else if (!remoteheads->next && common->next)
970 ;
971 /*
972 * We are not doing octopus and not fast forward. Need
973 * a real merge.
974 */
975 else if (!remoteheads->next && !common->next && option_commit) {
976 /*
977 * We are not doing octopus, not fast forward, and have
978 * only one common.
979 */
980 refresh_cache(REFRESH_QUIET);
981 if (allow_trivial) {
982 /* See if it is really trivial. */
983 git_committer_info(IDENT_ERROR_ON_NO_NAME);
984 printf("Trying really trivial in-index merge...\n");
985 if (!read_tree_trivial(common->item->object.sha1,
986 head, remoteheads->item->object.sha1))
987 return merge_trivial();
988 printf("Nope.\n");
989 }
990 } else {
991 /*
992 * An octopus. If we can reach all the remote we are up
993 * to date.
994 */
995 int up_to_date = 1;
996 struct commit_list *j;
997
998 for (j = remoteheads; j; j = j->next) {
999 struct commit_list *common_one;
1000
1001 /*
1002 * Here we *have* to calculate the individual
1003 * merge_bases again, otherwise "git merge HEAD^
1004 * HEAD^^" would be missed.
1005 */
1006 common_one = get_merge_bases(lookup_commit(head),
1007 j->item, 1);
1008 if (hashcmp(common_one->item->object.sha1,
1009 j->item->object.sha1)) {
1010 up_to_date = 0;
1011 break;
1012 }
1013 }
1014 if (up_to_date) {
1015 finish_up_to_date("Already up-to-date. Yeeah!");
1016 return 0;
1017 }
1018 }
1019
1020 /* We are going to make a new commit. */
1021 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1022
1023 /*
1024 * At this point, we need a real merge. No matter what strategy
1025 * we use, it would operate on the index, possibly affecting the
1026 * working tree, and when resolved cleanly, have the desired
1027 * tree in the index -- this means that the index must be in
1028 * sync with the head commit. The strategies are responsible
1029 * to ensure this.
1030 */
1031 if (use_strategies_nr != 1) {
1032 /*
1033 * Stash away the local changes so that we can try more
1034 * than one.
1035 */
1036 save_state();
1037 } else {
1038 memcpy(stash, null_sha1, 20);
1039 }
1040
1041 for (i = 0; i < use_strategies_nr; i++) {
1042 int ret;
1043 if (i) {
1044 printf("Rewinding the tree to pristine...\n");
1045 restore_state();
1046 }
1047 if (use_strategies_nr != 1)
1048 printf("Trying merge strategy %s...\n",
1049 use_strategies[i]->name);
1050 /*
1051 * Remember which strategy left the state in the working
1052 * tree.
1053 */
1054 wt_strategy = use_strategies[i]->name;
1055
1056 ret = try_merge_strategy(use_strategies[i]->name,
1057 common, head_arg);
1058 if (!option_commit && !ret) {
1059 merge_was_ok = 1;
1060 /*
1061 * This is necessary here just to avoid writing
1062 * the tree, but later we will *not* exit with
1063 * status code 1 because merge_was_ok is set.
1064 */
1065 ret = 1;
1066 }
1067
1068 if (ret) {
1069 /*
1070 * The backend exits with 1 when conflicts are
1071 * left to be resolved, with 2 when it does not
1072 * handle the given merge at all.
1073 */
1074 if (ret == 1) {
1075 int cnt = evaluate_result();
1076
1077 if (best_cnt <= 0 || cnt <= best_cnt) {
1078 best_strategy = use_strategies[i]->name;
1079 best_cnt = cnt;
1080 }
1081 }
1082 if (merge_was_ok)
1083 break;
1084 else
1085 continue;
1086 }
1087
1088 /* Automerge succeeded. */
1089 write_tree_trivial(result_tree);
1090 automerge_was_ok = 1;
1091 break;
1092 }
1093
1094 /*
1095 * If we have a resulting tree, that means the strategy module
1096 * auto resolved the merge cleanly.
1097 */
1098 if (automerge_was_ok)
1099 return finish_automerge(common, result_tree, wt_strategy);
1100
1101 /*
1102 * Pick the result from the best strategy and have the user fix
1103 * it up.
1104 */
1105 if (!best_strategy) {
1106 restore_state();
1107 if (use_strategies_nr > 1)
1108 fprintf(stderr,
1109 "No merge strategy handled the merge.\n");
1110 else
1111 fprintf(stderr, "Merge with strategy %s failed.\n",
1112 use_strategies[0]->name);
1113 return 2;
1114 } else if (best_strategy == wt_strategy)
1115 ; /* We already have its result in the working tree. */
1116 else {
1117 printf("Rewinding the tree to pristine...\n");
1118 restore_state();
1119 printf("Using the %s to prepare resolving by hand.\n",
1120 best_strategy);
1121 try_merge_strategy(best_strategy, common, head_arg);
1122 }
1123
1124 if (squash)
1125 finish(NULL, NULL);
1126 else {
1127 int fd;
1128 struct commit_list *j;
1129
1130 for (j = remoteheads; j; j = j->next)
1131 strbuf_addf(&buf, "%s\n",
1132 sha1_to_hex(j->item->object.sha1));
1133 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1134 if (fd < 0)
1135 die("Could open %s for writing",
1136 git_path("MERGE_HEAD"));
1137 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1138 die("Could not write to %s", git_path("MERGE_HEAD"));
1139 close(fd);
1140 strbuf_addch(&merge_msg, '\n');
1141 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1142 if (fd < 0)
1143 die("Could open %s for writing", git_path("MERGE_MSG"));
1144 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1145 merge_msg.len)
1146 die("Could not write to %s", git_path("MERGE_MSG"));
1147 close(fd);
1148 }
1149
1150 if (merge_was_ok) {
1151 fprintf(stderr, "Automatic merge went well; "
1152 "stopped before committing as requested\n");
1153 return 0;
1154 } else
1155 return suggest_conflicts();
1156 }