Build in merge
[git/git.git] / builtin-merge.c
CommitLineData
1c7b76be
MV
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
25#define DEFAULT_TWOHEAD (1<<0)
26#define DEFAULT_OCTOPUS (1<<1)
27#define NO_FAST_FORWARD (1<<2)
28#define NO_TRIVIAL (1<<3)
29
30struct strategy {
31 const char *name;
32 unsigned attr;
33};
34
35static const char * const builtin_merge_usage[] = {
36 "git-merge [options] <remote>...",
37 "git-merge [options] <msg> HEAD <remote>",
38 NULL
39};
40
41static int show_diffstat = 1, option_log, squash;
42static int option_commit = 1, allow_fast_forward = 1;
43static int allow_trivial = 1, have_message;
44static struct strbuf merge_msg;
45static struct commit_list *remoteheads;
46static unsigned char head[20], stash[20];
47static struct strategy **use_strategies;
48static size_t use_strategies_nr, use_strategies_alloc;
49static const char *branch;
50
51static struct strategy all_strategy[] = {
52 { "recur", NO_TRIVIAL },
53 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
54 { "octopus", DEFAULT_OCTOPUS },
55 { "resolve", 0 },
56 { "stupid", 0 },
57 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
58 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
59};
60
61static const char *pull_twohead, *pull_octopus;
62
63static int option_parse_message(const struct option *opt,
64 const char *arg, int unset)
65{
66 struct strbuf *buf = opt->value;
67
68 if (unset)
69 strbuf_setlen(buf, 0);
70 else {
71 strbuf_addf(buf, "%s\n\n", arg);
72 have_message = 1;
73 }
74 return 0;
75}
76
77static struct strategy *get_strategy(const char *name)
78{
79 int i;
80
81 if (!name)
82 return NULL;
83
84 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
85 if (!strcmp(name, all_strategy[i].name))
86 return &all_strategy[i];
87 return NULL;
88}
89
90static void append_strategy(struct strategy *s)
91{
92 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
93 use_strategies[use_strategies_nr++] = s;
94}
95
96static int option_parse_strategy(const struct option *opt,
97 const char *name, int unset)
98{
99 int i;
100 struct strategy *s;
101
102 if (unset)
103 return 0;
104
105 s = get_strategy(name);
106
107 if (s)
108 append_strategy(s);
109 else {
110 struct strbuf err;
111 strbuf_init(&err, 0);
112 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
113 strbuf_addf(&err, " %s", all_strategy[i].name);
114 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
115 fprintf(stderr, "Available strategies are:%s.\n", err.buf);
116 exit(1);
117 }
118 return 0;
119}
120
121static int option_parse_n(const struct option *opt,
122 const char *arg, int unset)
123{
124 show_diffstat = unset;
125 return 0;
126}
127
128static struct option builtin_merge_options[] = {
129 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
130 "do not show a diffstat at the end of the merge",
131 PARSE_OPT_NOARG, option_parse_n },
132 OPT_BOOLEAN(0, "stat", &show_diffstat,
133 "show a diffstat at the end of the merge"),
134 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
135 OPT_BOOLEAN(0, "log", &option_log,
136 "add list of one-line log to merge commit message"),
137 OPT_BOOLEAN(0, "squash", &squash,
138 "create a single commit instead of doing a merge"),
139 OPT_BOOLEAN(0, "commit", &option_commit,
140 "perform a commit if the merge succeeds (default)"),
141 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
142 "allow fast forward (default)"),
143 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
144 "merge strategy to use", option_parse_strategy),
145 OPT_CALLBACK('m', "message", &merge_msg, "message",
146 "message to be used for the merge commit (if any)",
147 option_parse_message),
148 OPT_END()
149};
150
151/* Cleans up metadata that is uninteresting after a succeeded merge. */
152static void drop_save(void)
153{
154 unlink(git_path("MERGE_HEAD"));
155 unlink(git_path("MERGE_MSG"));
156}
157
158static void save_state(void)
159{
160 int len;
161 struct child_process cp;
162 struct strbuf buffer = STRBUF_INIT;
163 const char *argv[] = {"stash", "create", NULL};
164
165 memset(&cp, 0, sizeof(cp));
166 cp.argv = argv;
167 cp.out = -1;
168 cp.git_cmd = 1;
169
170 if (start_command(&cp))
171 die("could not run stash.");
172 len = strbuf_read(&buffer, cp.out, 1024);
173 close(cp.out);
174
175 if (finish_command(&cp) || len < 0)
176 die("stash failed");
177 else if (!len)
178 return;
179 strbuf_setlen(&buffer, buffer.len-1);
180 if (get_sha1(buffer.buf, stash))
181 die("not a valid object: %s", buffer.buf);
182}
183
184static void reset_hard(unsigned const char *sha1, int verbose)
185{
186 int i = 0;
187 const char *args[6];
188
189 args[i++] = "read-tree";
190 if (verbose)
191 args[i++] = "-v";
192 args[i++] = "--reset";
193 args[i++] = "-u";
194 args[i++] = sha1_to_hex(sha1);
195 args[i] = NULL;
196
197 if (run_command_v_opt(args, RUN_GIT_CMD))
198 die("read-tree failed");
199}
200
201static void restore_state(void)
202{
203 struct strbuf sb;
204 const char *args[] = { "stash", "apply", NULL, NULL };
205
206 if (is_null_sha1(stash))
207 return;
208
209 reset_hard(head, 1);
210
211 strbuf_init(&sb, 0);
212 args[2] = sha1_to_hex(stash);
213
214 /*
215 * It is OK to ignore error here, for example when there was
216 * nothing to restore.
217 */
218 run_command_v_opt(args, RUN_GIT_CMD);
219
220 strbuf_release(&sb);
221 refresh_cache(REFRESH_QUIET);
222}
223
224/* This is called when no merge was necessary. */
225static void finish_up_to_date(const char *msg)
226{
227 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
228 drop_save();
229}
230
231static void squash_message(void)
232{
233 struct rev_info rev;
234 struct commit *commit;
235 struct strbuf out;
236 struct commit_list *j;
237 int fd;
238
239 printf("Squash commit -- not updating HEAD\n");
240 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
241 if (fd < 0)
242 die("Could not write to %s", git_path("SQUASH_MSG"));
243
244 init_revisions(&rev, NULL);
245 rev.ignore_merges = 1;
246 rev.commit_format = CMIT_FMT_MEDIUM;
247
248 commit = lookup_commit(head);
249 commit->object.flags |= UNINTERESTING;
250 add_pending_object(&rev, &commit->object, NULL);
251
252 for (j = remoteheads; j; j = j->next)
253 add_pending_object(&rev, &j->item->object, NULL);
254
255 setup_revisions(0, NULL, &rev, NULL);
256 if (prepare_revision_walk(&rev))
257 die("revision walk setup failed");
258
259 strbuf_init(&out, 0);
260 strbuf_addstr(&out, "Squashed commit of the following:\n");
261 while ((commit = get_revision(&rev)) != NULL) {
262 strbuf_addch(&out, '\n');
263 strbuf_addf(&out, "commit %s\n",
264 sha1_to_hex(commit->object.sha1));
265 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
266 NULL, NULL, rev.date_mode, 0);
267 }
268 write(fd, out.buf, out.len);
269 close(fd);
270 strbuf_release(&out);
271}
272
273static int run_hook(const char *name)
274{
275 struct child_process hook;
276 const char *argv[3], *env[2];
277 char index[PATH_MAX];
278
279 argv[0] = git_path("hooks/%s", name);
280 if (access(argv[0], X_OK) < 0)
281 return 0;
282
283 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
284 env[0] = index;
285 env[1] = NULL;
286
287 if (squash)
288 argv[1] = "1";
289 else
290 argv[1] = "0";
291 argv[2] = NULL;
292
293 memset(&hook, 0, sizeof(hook));
294 hook.argv = argv;
295 hook.no_stdin = 1;
296 hook.stdout_to_stderr = 1;
297 hook.env = env;
298
299 return run_command(&hook);
300}
301
302static void finish(const unsigned char *new_head, const char *msg)
303{
304 struct strbuf reflog_message;
305
306 strbuf_init(&reflog_message, 0);
307 if (!msg)
308 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
309 else {
310 printf("%s\n", msg);
311 strbuf_addf(&reflog_message, "%s: %s",
312 getenv("GIT_REFLOG_ACTION"), msg);
313 }
314 if (squash) {
315 squash_message();
316 } else {
317 if (!merge_msg.len)
318 printf("No merge message -- not updating HEAD\n");
319 else {
320 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
321 update_ref(reflog_message.buf, "HEAD",
322 new_head, head, 0,
323 DIE_ON_ERR);
324 /*
325 * We ignore errors in 'gc --auto', since the
326 * user should see them.
327 */
328 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
329 }
330 }
331 if (new_head && show_diffstat) {
332 struct diff_options opts;
333 diff_setup(&opts);
334 opts.output_format |=
335 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
336 opts.detect_rename = DIFF_DETECT_RENAME;
337 if (diff_use_color_default > 0)
338 DIFF_OPT_SET(&opts, COLOR_DIFF);
339 if (diff_setup_done(&opts) < 0)
340 die("diff_setup_done failed");
341 diff_tree_sha1(head, new_head, "", &opts);
342 diffcore_std(&opts);
343 diff_flush(&opts);
344 }
345
346 /* Run a post-merge hook */
347 run_hook("post-merge");
348
349 strbuf_release(&reflog_message);
350}
351
352/* Get the name for the merge commit's message. */
353static void merge_name(const char *remote, struct strbuf *msg)
354{
355 struct object *remote_head;
356 unsigned char branch_head[20], buf_sha[20];
357 struct strbuf buf;
358 const char *ptr;
359 int len, early;
360
361 memset(branch_head, 0, sizeof(branch_head));
362 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
363 if (!remote_head)
364 die("'%s' does not point to a commit", remote);
365
366 strbuf_init(&buf, 0);
367 strbuf_addstr(&buf, "refs/heads/");
368 strbuf_addstr(&buf, remote);
369 resolve_ref(buf.buf, branch_head, 0, 0);
370
371 if (!hashcmp(remote_head->sha1, branch_head)) {
372 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
373 sha1_to_hex(branch_head), remote);
374 return;
375 }
376
377 /* See if remote matches <name>^^^.. or <name>~<number> */
378 for (len = 0, ptr = remote + strlen(remote);
379 remote < ptr && ptr[-1] == '^';
380 ptr--)
381 len++;
382 if (len)
383 early = 1;
384 else {
385 early = 0;
386 ptr = strrchr(remote, '~');
387 if (ptr) {
388 int seen_nonzero = 0;
389
390 len++; /* count ~ */
391 while (*++ptr && isdigit(*ptr)) {
392 seen_nonzero |= (*ptr != '0');
393 len++;
394 }
395 if (*ptr)
396 len = 0; /* not ...~<number> */
397 else if (seen_nonzero)
398 early = 1;
399 else if (len == 1)
400 early = 1; /* "name~" is "name~1"! */
401 }
402 }
403 if (len) {
404 struct strbuf truname = STRBUF_INIT;
405 strbuf_addstr(&truname, "refs/heads/");
406 strbuf_addstr(&truname, remote);
407 strbuf_setlen(&truname, len+11);
408 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
409 strbuf_addf(msg,
410 "%s\t\tbranch '%s'%s of .\n",
411 sha1_to_hex(remote_head->sha1),
412 truname.buf,
413 (early ? " (early part)" : ""));
414 return;
415 }
416 }
417
418 if (!strcmp(remote, "FETCH_HEAD") &&
419 !access(git_path("FETCH_HEAD"), R_OK)) {
420 FILE *fp;
421 struct strbuf line;
422 char *ptr;
423
424 strbuf_init(&line, 0);
425 fp = fopen(git_path("FETCH_HEAD"), "r");
426 if (!fp)
427 die("could not open %s for reading: %s",
428 git_path("FETCH_HEAD"), strerror(errno));
429 strbuf_getline(&line, fp, '\n');
430 fclose(fp);
431 ptr = strstr(line.buf, "\tnot-for-merge\t");
432 if (ptr)
433 strbuf_remove(&line, ptr-line.buf+1, 13);
434 strbuf_addbuf(msg, &line);
435 strbuf_release(&line);
436 return;
437 }
438 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
439 sha1_to_hex(remote_head->sha1), remote);
440}
441
442int git_merge_config(const char *k, const char *v, void *cb)
443{
444 if (branch && !prefixcmp(k, "branch.") &&
445 !prefixcmp(k + 7, branch) &&
446 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
447 const char **argv;
448 int argc;
449 char *buf;
450
451 buf = xstrdup(v);
452 argc = split_cmdline(buf, &argv);
453 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
454 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
455 argc++;
456 parse_options(argc, argv, builtin_merge_options,
457 builtin_merge_usage, 0);
458 free(buf);
459 }
460
461 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
462 show_diffstat = git_config_bool(k, v);
463 else if (!strcmp(k, "pull.twohead"))
464 return git_config_string(&pull_twohead, k, v);
465 else if (!strcmp(k, "pull.octopus"))
466 return git_config_string(&pull_octopus, k, v);
467 return git_diff_ui_config(k, v, cb);
468}
469
470static int read_tree_trivial(unsigned char *common, unsigned char *head,
471 unsigned char *one)
472{
473 int i, nr_trees = 0;
474 struct tree *trees[MAX_UNPACK_TREES];
475 struct tree_desc t[MAX_UNPACK_TREES];
476 struct unpack_trees_options opts;
477
478 memset(&opts, 0, sizeof(opts));
479 opts.head_idx = 2;
480 opts.src_index = &the_index;
481 opts.dst_index = &the_index;
482 opts.update = 1;
483 opts.verbose_update = 1;
484 opts.trivial_merges_only = 1;
485 opts.merge = 1;
486 trees[nr_trees] = parse_tree_indirect(common);
487 if (!trees[nr_trees++])
488 return -1;
489 trees[nr_trees] = parse_tree_indirect(head);
490 if (!trees[nr_trees++])
491 return -1;
492 trees[nr_trees] = parse_tree_indirect(one);
493 if (!trees[nr_trees++])
494 return -1;
495 opts.fn = threeway_merge;
496 cache_tree_free(&active_cache_tree);
497 for (i = 0; i < nr_trees; i++) {
498 parse_tree(trees[i]);
499 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
500 }
501 if (unpack_trees(nr_trees, t, &opts))
502 return -1;
503 return 0;
504}
505
506static void write_tree_trivial(unsigned char *sha1)
507{
508 if (write_cache_as_tree(sha1, 0, NULL))
509 die("git write-tree failed to write a tree");
510}
511
512static int try_merge_strategy(const char *strategy, struct commit_list *common,
513 const char *head_arg)
514{
515 const char **args;
516 int i = 0, ret;
517 struct commit_list *j;
518 struct strbuf buf;
519
520 args = xmalloc((4 + commit_list_count(common) +
521 commit_list_count(remoteheads)) * sizeof(char *));
522 strbuf_init(&buf, 0);
523 strbuf_addf(&buf, "merge-%s", strategy);
524 args[i++] = buf.buf;
525 for (j = common; j; j = j->next)
526 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
527 args[i++] = "--";
528 args[i++] = head_arg;
529 for (j = remoteheads; j; j = j->next)
530 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
531 args[i] = NULL;
532 ret = run_command_v_opt(args, RUN_GIT_CMD);
533 strbuf_release(&buf);
534 i = 1;
535 for (j = common; j; j = j->next)
536 free((void *)args[i++]);
537 i += 2;
538 for (j = remoteheads; j; j = j->next)
539 free((void *)args[i++]);
540 free(args);
541 return -ret;
542}
543
544static void count_diff_files(struct diff_queue_struct *q,
545 struct diff_options *opt, void *data)
546{
547 int *count = data;
548
549 (*count) += q->nr;
550}
551
552static int count_unmerged_entries(void)
553{
554 const struct index_state *state = &the_index;
555 int i, ret = 0;
556
557 for (i = 0; i < state->cache_nr; i++)
558 if (ce_stage(state->cache[i]))
559 ret++;
560
561 return ret;
562}
563
564static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
565{
566 struct tree *trees[MAX_UNPACK_TREES];
567 struct unpack_trees_options opts;
568 struct tree_desc t[MAX_UNPACK_TREES];
569 int i, fd, nr_trees = 0;
570 struct dir_struct dir;
571 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
572
573 if (read_cache_unmerged())
574 die("you need to resolve your current index first");
575
576 fd = hold_locked_index(lock_file, 1);
577
578 memset(&trees, 0, sizeof(trees));
579 memset(&opts, 0, sizeof(opts));
580 memset(&t, 0, sizeof(t));
581 dir.show_ignored = 1;
582 dir.exclude_per_dir = ".gitignore";
583 opts.dir = &dir;
584
585 opts.head_idx = 1;
586 opts.src_index = &the_index;
587 opts.dst_index = &the_index;
588 opts.update = 1;
589 opts.verbose_update = 1;
590 opts.merge = 1;
591 opts.fn = twoway_merge;
592
593 trees[nr_trees] = parse_tree_indirect(head);
594 if (!trees[nr_trees++])
595 return -1;
596 trees[nr_trees] = parse_tree_indirect(remote);
597 if (!trees[nr_trees++])
598 return -1;
599 for (i = 0; i < nr_trees; i++) {
600 parse_tree(trees[i]);
601 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
602 }
603 if (unpack_trees(nr_trees, t, &opts))
604 return -1;
605 if (write_cache(fd, active_cache, active_nr) ||
606 commit_locked_index(lock_file))
607 die("unable to write new index file");
608 return 0;
609}
610
611static void split_merge_strategies(const char *string, struct strategy **list,
612 int *nr, int *alloc)
613{
614 char *p, *q, *buf;
615
616 if (!string)
617 return;
618
619 buf = xstrdup(string);
620 q = buf;
621 for (;;) {
622 p = strchr(q, ' ');
623 if (!p) {
624 ALLOC_GROW(*list, *nr + 1, *alloc);
625 (*list)[(*nr)++].name = xstrdup(q);
626 free(buf);
627 return;
628 } else {
629 *p = '\0';
630 ALLOC_GROW(*list, *nr + 1, *alloc);
631 (*list)[(*nr)++].name = xstrdup(q);
632 q = ++p;
633 }
634 }
635}
636
637static void add_strategies(const char *string, unsigned attr)
638{
639 struct strategy *list = NULL;
640 int list_alloc = 0, list_nr = 0, i;
641
642 memset(&list, 0, sizeof(list));
643 split_merge_strategies(string, &list, &list_nr, &list_alloc);
644 if (list != NULL) {
645 for (i = 0; i < list_nr; i++) {
646 struct strategy *s;
647
648 s = get_strategy(list[i].name);
649 if (s)
650 append_strategy(s);
651 }
652 return;
653 }
654 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
655 if (all_strategy[i].attr & attr)
656 append_strategy(&all_strategy[i]);
657
658}
659
660static int merge_trivial(void)
661{
662 unsigned char result_tree[20], result_commit[20];
663 struct commit_list parent;
664
665 write_tree_trivial(result_tree);
666 printf("Wonderful.\n");
667 parent.item = remoteheads->item;
668 parent.next = NULL;
669 commit_tree(merge_msg.buf, result_tree, &parent, result_commit);
670 finish(result_commit, "In-index merge");
671 drop_save();
672 return 0;
673}
674
675static int finish_automerge(struct commit_list *common,
676 unsigned char *result_tree,
677 const char *wt_strategy)
678{
679 struct commit_list *parents = NULL, *j;
680 struct strbuf buf = STRBUF_INIT;
681 unsigned char result_commit[20];
682
683 free_commit_list(common);
684 if (allow_fast_forward) {
685 parents = remoteheads;
686 commit_list_insert(lookup_commit(head), &parents);
687 parents = reduce_heads(parents);
688 } else {
689 struct commit_list **pptr = &parents;
690
691 pptr = &commit_list_insert(lookup_commit(head),
692 pptr)->next;
693 for (j = remoteheads; j; j = j->next)
694 pptr = &commit_list_insert(j->item, pptr)->next;
695 }
696 free_commit_list(remoteheads);
697 strbuf_addch(&merge_msg, '\n');
698 commit_tree(merge_msg.buf, result_tree, parents, result_commit);
699 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
700 finish(result_commit, buf.buf);
701 strbuf_release(&buf);
702 drop_save();
703 return 0;
704}
705
706static int suggest_conflicts(void)
707{
708 FILE *fp;
709 int pos;
710
711 fp = fopen(git_path("MERGE_MSG"), "a");
712 if (!fp)
713 die("Could open %s for writing", git_path("MERGE_MSG"));
714 fprintf(fp, "\nConflicts:\n");
715 for (pos = 0; pos < active_nr; pos++) {
716 struct cache_entry *ce = active_cache[pos];
717
718 if (ce_stage(ce)) {
719 fprintf(fp, "\t%s\n", ce->name);
720 while (pos + 1 < active_nr &&
721 !strcmp(ce->name,
722 active_cache[pos + 1]->name))
723 pos++;
724 }
725 }
726 fclose(fp);
727 rerere();
728 printf("Automatic merge failed; "
729 "fix conflicts and then commit the result.\n");
730 return 1;
731}
732
733static struct commit *is_old_style_invocation(int argc, const char **argv)
734{
735 struct commit *second_token = NULL;
736 if (argc > 1) {
737 unsigned char second_sha1[20];
738
739 if (get_sha1(argv[1], second_sha1))
740 return NULL;
741 second_token = lookup_commit_reference_gently(second_sha1, 0);
742 if (!second_token)
743 die("'%s' is not a commit", argv[1]);
744 if (hashcmp(second_token->object.sha1, head))
745 return NULL;
746 }
747 return second_token;
748}
749
750static int evaluate_result(void)
751{
752 int cnt = 0;
753 struct rev_info rev;
754
755 if (read_cache() < 0)
756 die("failed to read the cache");
757
758 /* Check how many files differ. */
759 init_revisions(&rev, "");
760 setup_revisions(0, NULL, &rev, NULL);
761 rev.diffopt.output_format |=
762 DIFF_FORMAT_CALLBACK;
763 rev.diffopt.format_callback = count_diff_files;
764 rev.diffopt.format_callback_data = &cnt;
765 run_diff_files(&rev, 0);
766
767 /*
768 * Check how many unmerged entries are
769 * there.
770 */
771 cnt += count_unmerged_entries();
772
773 return cnt;
774}
775
776int cmd_merge(int argc, const char **argv, const char *prefix)
777{
778 unsigned char result_tree[20];
779 struct strbuf buf;
780 const char *head_arg;
781 int flag, head_invalid = 0, i;
782 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
783 struct commit_list *common = NULL;
784 const char *best_strategy = NULL, *wt_strategy = NULL;
785 struct commit_list **remotes = &remoteheads;
786
787 setup_work_tree();
788 if (unmerged_cache())
789 die("You are in the middle of a conflicted merge.");
790
791 /*
792 * Check if we are _not_ on a detached HEAD, i.e. if there is a
793 * current branch.
794 */
795 branch = resolve_ref("HEAD", head, 0, &flag);
796 if (branch && !prefixcmp(branch, "refs/heads/"))
797 branch += 11;
798 if (is_null_sha1(head))
799 head_invalid = 1;
800
801 git_config(git_merge_config, NULL);
802
803 /* for color.ui */
804 if (diff_use_color_default == -1)
805 diff_use_color_default = git_use_color_default;
806
807 argc = parse_options(argc, argv, builtin_merge_options,
808 builtin_merge_usage, 0);
809
810 if (squash) {
811 if (!allow_fast_forward)
812 die("You cannot combine --squash with --no-ff.");
813 option_commit = 0;
814 }
815
816 if (!argc)
817 usage_with_options(builtin_merge_usage,
818 builtin_merge_options);
819
820 /*
821 * This could be traditional "merge <msg> HEAD <commit>..." and
822 * the way we can tell it is to see if the second token is HEAD,
823 * but some people might have misused the interface and used a
824 * committish that is the same as HEAD there instead.
825 * Traditional format never would have "-m" so it is an
826 * additional safety measure to check for it.
827 */
828 strbuf_init(&buf, 0);
829
830 if (!have_message && is_old_style_invocation(argc, argv)) {
831 strbuf_addstr(&merge_msg, argv[0]);
832 head_arg = argv[1];
833 argv += 2;
834 argc -= 2;
835 } else if (head_invalid) {
836 struct object *remote_head;
837 /*
838 * If the merged head is a valid one there is no reason
839 * to forbid "git merge" into a branch yet to be born.
840 * We do the same for "git pull".
841 */
842 if (argc != 1)
843 die("Can merge only exactly one commit into "
844 "empty head");
845 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
846 if (!remote_head)
847 die("%s - not something we can merge", argv[0]);
848 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
849 DIE_ON_ERR);
850 reset_hard(remote_head->sha1, 0);
851 return 0;
852 } else {
853 struct strbuf msg;
854
855 /* We are invoked directly as the first-class UI. */
856 head_arg = "HEAD";
857
858 /*
859 * All the rest are the commits being merged;
860 * prepare the standard merge summary message to
861 * be appended to the given message. If remote
862 * is invalid we will die later in the common
863 * codepath so we discard the error in this
864 * loop.
865 */
866 strbuf_init(&msg, 0);
867 for (i = 0; i < argc; i++)
868 merge_name(argv[i], &msg);
869 fmt_merge_msg(option_log, &msg, &merge_msg);
870 if (merge_msg.len)
871 strbuf_setlen(&merge_msg, merge_msg.len-1);
872 }
873
874 if (head_invalid || !argc)
875 usage_with_options(builtin_merge_usage,
876 builtin_merge_options);
877
878 strbuf_addstr(&buf, "merge");
879 for (i = 0; i < argc; i++)
880 strbuf_addf(&buf, " %s", argv[i]);
881 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
882 strbuf_reset(&buf);
883
884 for (i = 0; i < argc; i++) {
885 struct object *o;
886
887 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
888 if (!o)
889 die("%s - not something we can merge", argv[i]);
890 remotes = &commit_list_insert(lookup_commit(o->sha1),
891 remotes)->next;
892
893 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
894 setenv(buf.buf, argv[i], 1);
895 strbuf_reset(&buf);
896 }
897
898 if (!use_strategies) {
899 if (!remoteheads->next)
900 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
901 else
902 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
903 }
904
905 for (i = 0; i < use_strategies_nr; i++) {
906 if (use_strategies[i]->attr & NO_FAST_FORWARD)
907 allow_fast_forward = 0;
908 if (use_strategies[i]->attr & NO_TRIVIAL)
909 allow_trivial = 0;
910 }
911
912 if (!remoteheads->next)
913 common = get_merge_bases(lookup_commit(head),
914 remoteheads->item, 1);
915 else {
916 struct commit_list *list = remoteheads;
917 commit_list_insert(lookup_commit(head), &list);
918 common = get_octopus_merge_bases(list);
919 free(list);
920 }
921
922 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
923 DIE_ON_ERR);
924
925 if (!common)
926 ; /* No common ancestors found. We need a real merge. */
927 else if (!remoteheads->next && !common->next &&
928 common->item == remoteheads->item) {
929 /*
930 * If head can reach all the merge then we are up to date.
931 * but first the most common case of merging one remote.
932 */
933 finish_up_to_date("Already up-to-date.");
934 return 0;
935 } else if (allow_fast_forward && !remoteheads->next &&
936 !common->next &&
937 !hashcmp(common->item->object.sha1, head)) {
938 /* Again the most common case of merging one remote. */
939 struct strbuf msg;
940 struct object *o;
941 char hex[41];
942
943 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
944
945 printf("Updating %s..%s\n",
946 hex,
947 find_unique_abbrev(remoteheads->item->object.sha1,
948 DEFAULT_ABBREV));
949 refresh_cache(REFRESH_QUIET);
950 strbuf_init(&msg, 0);
951 strbuf_addstr(&msg, "Fast forward");
952 if (have_message)
953 strbuf_addstr(&msg,
954 " (no commit created; -m option ignored)");
955 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
956 0, NULL, OBJ_COMMIT);
957 if (!o)
958 return 1;
959
960 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
961 return 1;
962
963 finish(o->sha1, msg.buf);
964 drop_save();
965 return 0;
966 } else if (!remoteheads->next && common->next)
967 ;
968 /*
969 * We are not doing octopus and not fast forward. Need
970 * a real merge.
971 */
972 else if (!remoteheads->next && !common->next && option_commit) {
973 /*
974 * We are not doing octopus, not fast forward, and have
975 * only one common.
976 */
977 refresh_cache(REFRESH_QUIET);
978 if (allow_trivial) {
979 /* See if it is really trivial. */
980 git_committer_info(IDENT_ERROR_ON_NO_NAME);
981 printf("Trying really trivial in-index merge...\n");
982 if (!read_tree_trivial(common->item->object.sha1,
983 head, remoteheads->item->object.sha1))
984 return merge_trivial();
985 printf("Nope.\n");
986 }
987 } else {
988 /*
989 * An octopus. If we can reach all the remote we are up
990 * to date.
991 */
992 int up_to_date = 1;
993 struct commit_list *j;
994
995 for (j = remoteheads; j; j = j->next) {
996 struct commit_list *common_one;
997
998 /*
999 * Here we *have* to calculate the individual
1000 * merge_bases again, otherwise "git merge HEAD^
1001 * HEAD^^" would be missed.
1002 */
1003 common_one = get_merge_bases(lookup_commit(head),
1004 j->item, 1);
1005 if (hashcmp(common_one->item->object.sha1,
1006 j->item->object.sha1)) {
1007 up_to_date = 0;
1008 break;
1009 }
1010 }
1011 if (up_to_date) {
1012 finish_up_to_date("Already up-to-date. Yeeah!");
1013 return 0;
1014 }
1015 }
1016
1017 /* We are going to make a new commit. */
1018 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1019
1020 /*
1021 * At this point, we need a real merge. No matter what strategy
1022 * we use, it would operate on the index, possibly affecting the
1023 * working tree, and when resolved cleanly, have the desired
1024 * tree in the index -- this means that the index must be in
1025 * sync with the head commit. The strategies are responsible
1026 * to ensure this.
1027 */
1028 if (use_strategies_nr != 1) {
1029 /*
1030 * Stash away the local changes so that we can try more
1031 * than one.
1032 */
1033 save_state();
1034 } else {
1035 memcpy(stash, null_sha1, 20);
1036 }
1037
1038 for (i = 0; i < use_strategies_nr; i++) {
1039 int ret;
1040 if (i) {
1041 printf("Rewinding the tree to pristine...\n");
1042 restore_state();
1043 }
1044 if (use_strategies_nr != 1)
1045 printf("Trying merge strategy %s...\n",
1046 use_strategies[i]->name);
1047 /*
1048 * Remember which strategy left the state in the working
1049 * tree.
1050 */
1051 wt_strategy = use_strategies[i]->name;
1052
1053 ret = try_merge_strategy(use_strategies[i]->name,
1054 common, head_arg);
1055 if (!option_commit && !ret) {
1056 merge_was_ok = 1;
1057 /*
1058 * This is necessary here just to avoid writing
1059 * the tree, but later we will *not* exit with
1060 * status code 1 because merge_was_ok is set.
1061 */
1062 ret = 1;
1063 }
1064
1065 if (ret) {
1066 /*
1067 * The backend exits with 1 when conflicts are
1068 * left to be resolved, with 2 when it does not
1069 * handle the given merge at all.
1070 */
1071 if (ret == 1) {
1072 int cnt = evaluate_result();
1073
1074 if (best_cnt <= 0 || cnt <= best_cnt) {
1075 best_strategy = use_strategies[i]->name;
1076 best_cnt = cnt;
1077 }
1078 }
1079 if (merge_was_ok)
1080 break;
1081 else
1082 continue;
1083 }
1084
1085 /* Automerge succeeded. */
1086 write_tree_trivial(result_tree);
1087 automerge_was_ok = 1;
1088 break;
1089 }
1090
1091 /*
1092 * If we have a resulting tree, that means the strategy module
1093 * auto resolved the merge cleanly.
1094 */
1095 if (automerge_was_ok)
1096 return finish_automerge(common, result_tree, wt_strategy);
1097
1098 /*
1099 * Pick the result from the best strategy and have the user fix
1100 * it up.
1101 */
1102 if (!best_strategy) {
1103 restore_state();
1104 if (use_strategies_nr > 1)
1105 fprintf(stderr,
1106 "No merge strategy handled the merge.\n");
1107 else
1108 fprintf(stderr, "Merge with strategy %s failed.\n",
1109 use_strategies[0]->name);
1110 return 2;
1111 } else if (best_strategy == wt_strategy)
1112 ; /* We already have its result in the working tree. */
1113 else {
1114 printf("Rewinding the tree to pristine...\n");
1115 restore_state();
1116 printf("Using the %s to prepare resolving by hand.\n",
1117 best_strategy);
1118 try_merge_strategy(best_strategy, common, head_arg);
1119 }
1120
1121 if (squash)
1122 finish(NULL, NULL);
1123 else {
1124 int fd;
1125 struct commit_list *j;
1126
1127 for (j = remoteheads; j; j = j->next)
1128 strbuf_addf(&buf, "%s\n",
1129 sha1_to_hex(j->item->object.sha1));
1130 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1131 if (fd < 0)
1132 die("Could open %s for writing",
1133 git_path("MERGE_HEAD"));
1134 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1135 die("Could not write to %s", git_path("MERGE_HEAD"));
1136 close(fd);
1137 strbuf_addch(&merge_msg, '\n');
1138 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1139 if (fd < 0)
1140 die("Could open %s for writing", git_path("MERGE_MSG"));
1141 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1142 merge_msg.len)
1143 die("Could not write to %s", git_path("MERGE_MSG"));
1144 close(fd);
1145 }
1146
1147 if (merge_was_ok) {
1148 fprintf(stderr, "Automatic merge went well; "
1149 "stopped before committing as requested\n");
1150 return 0;
1151 } else
1152 return suggest_conflicts();
1153}