Merge branch 'maint'
[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 #include "help.h"
26
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)
31
32 struct strategy {
33 const char *name;
34 unsigned attr;
35 };
36
37 static const char * const builtin_merge_usage[] = {
38 "git-merge [options] <remote>...",
39 "git-merge [options] <msg> HEAD <remote>",
40 NULL
41 };
42
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;
52
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 },
59 };
60
61 static const char *pull_twohead, *pull_octopus;
62
63 static 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 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;
76 }
77
78 static struct strategy *get_strategy(const char *name)
79 {
80 int i;
81 struct strategy *ret;
82 static struct cmdnames main_cmds, other_cmds;
83 static int loaded;
84
85 if (!name)
86 return NULL;
87
88 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
89 if (!strcmp(name, all_strategy[i].name))
90 return &all_strategy[i];
91
92 if (!loaded) {
93 struct cmdnames not_strategies;
94 loaded = 1;
95
96 memset(&not_strategies, 0, sizeof(struct cmdnames));
97 load_command_list("git-merge-", &main_cmds, &other_cmds);
98 for (i = 0; i < main_cmds.cnt; i++) {
99 int j, found = 0;
100 struct cmdname *ent = main_cmds.names[i];
101 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
102 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
103 && !all_strategy[j].name[ent->len])
104 found = 1;
105 if (!found)
106 add_cmdname(&not_strategies, ent->name, ent->len);
107 exclude_cmds(&main_cmds, &not_strategies);
108 }
109 }
110 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
111 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
112 fprintf(stderr, "Available strategies are:");
113 for (i = 0; i < main_cmds.cnt; i++)
114 fprintf(stderr, " %s", main_cmds.names[i]->name);
115 fprintf(stderr, ".\n");
116 if (other_cmds.cnt) {
117 fprintf(stderr, "Available custom strategies are:");
118 for (i = 0; i < other_cmds.cnt; i++)
119 fprintf(stderr, " %s", other_cmds.names[i]->name);
120 fprintf(stderr, ".\n");
121 }
122 exit(1);
123 }
124
125 ret = xmalloc(sizeof(struct strategy));
126 memset(ret, 0, sizeof(struct strategy));
127 ret->name = xstrdup(name);
128 return ret;
129 }
130
131 static void append_strategy(struct strategy *s)
132 {
133 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
134 use_strategies[use_strategies_nr++] = s;
135 }
136
137 static int option_parse_strategy(const struct option *opt,
138 const char *name, int unset)
139 {
140 if (unset)
141 return 0;
142
143 append_strategy(get_strategy(name));
144 return 0;
145 }
146
147 static int option_parse_n(const struct option *opt,
148 const char *arg, int unset)
149 {
150 show_diffstat = unset;
151 return 0;
152 }
153
154 static struct option builtin_merge_options[] = {
155 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
156 "do not show a diffstat at the end of the merge",
157 PARSE_OPT_NOARG, option_parse_n },
158 OPT_BOOLEAN(0, "stat", &show_diffstat,
159 "show a diffstat at the end of the merge"),
160 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
161 OPT_BOOLEAN(0, "log", &option_log,
162 "add list of one-line log to merge commit message"),
163 OPT_BOOLEAN(0, "squash", &squash,
164 "create a single commit instead of doing a merge"),
165 OPT_BOOLEAN(0, "commit", &option_commit,
166 "perform a commit if the merge succeeds (default)"),
167 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
168 "allow fast forward (default)"),
169 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
170 "merge strategy to use", option_parse_strategy),
171 OPT_CALLBACK('m', "message", &merge_msg, "message",
172 "message to be used for the merge commit (if any)",
173 option_parse_message),
174 OPT_END()
175 };
176
177 /* Cleans up metadata that is uninteresting after a succeeded merge. */
178 static void drop_save(void)
179 {
180 unlink(git_path("MERGE_HEAD"));
181 unlink(git_path("MERGE_MSG"));
182 }
183
184 static void save_state(void)
185 {
186 int len;
187 struct child_process cp;
188 struct strbuf buffer = STRBUF_INIT;
189 const char *argv[] = {"stash", "create", NULL};
190
191 memset(&cp, 0, sizeof(cp));
192 cp.argv = argv;
193 cp.out = -1;
194 cp.git_cmd = 1;
195
196 if (start_command(&cp))
197 die("could not run stash.");
198 len = strbuf_read(&buffer, cp.out, 1024);
199 close(cp.out);
200
201 if (finish_command(&cp) || len < 0)
202 die("stash failed");
203 else if (!len)
204 return;
205 strbuf_setlen(&buffer, buffer.len-1);
206 if (get_sha1(buffer.buf, stash))
207 die("not a valid object: %s", buffer.buf);
208 }
209
210 static void reset_hard(unsigned const char *sha1, int verbose)
211 {
212 int i = 0;
213 const char *args[6];
214
215 args[i++] = "read-tree";
216 if (verbose)
217 args[i++] = "-v";
218 args[i++] = "--reset";
219 args[i++] = "-u";
220 args[i++] = sha1_to_hex(sha1);
221 args[i] = NULL;
222
223 if (run_command_v_opt(args, RUN_GIT_CMD))
224 die("read-tree failed");
225 }
226
227 static void restore_state(void)
228 {
229 struct strbuf sb;
230 const char *args[] = { "stash", "apply", NULL, NULL };
231
232 if (is_null_sha1(stash))
233 return;
234
235 reset_hard(head, 1);
236
237 strbuf_init(&sb, 0);
238 args[2] = sha1_to_hex(stash);
239
240 /*
241 * It is OK to ignore error here, for example when there was
242 * nothing to restore.
243 */
244 run_command_v_opt(args, RUN_GIT_CMD);
245
246 strbuf_release(&sb);
247 refresh_cache(REFRESH_QUIET);
248 }
249
250 /* This is called when no merge was necessary. */
251 static void finish_up_to_date(const char *msg)
252 {
253 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
254 drop_save();
255 }
256
257 static void squash_message(void)
258 {
259 struct rev_info rev;
260 struct commit *commit;
261 struct strbuf out;
262 struct commit_list *j;
263 int fd;
264
265 printf("Squash commit -- not updating HEAD\n");
266 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
267 if (fd < 0)
268 die("Could not write to %s", git_path("SQUASH_MSG"));
269
270 init_revisions(&rev, NULL);
271 rev.ignore_merges = 1;
272 rev.commit_format = CMIT_FMT_MEDIUM;
273
274 commit = lookup_commit(head);
275 commit->object.flags |= UNINTERESTING;
276 add_pending_object(&rev, &commit->object, NULL);
277
278 for (j = remoteheads; j; j = j->next)
279 add_pending_object(&rev, &j->item->object, NULL);
280
281 setup_revisions(0, NULL, &rev, NULL);
282 if (prepare_revision_walk(&rev))
283 die("revision walk setup failed");
284
285 strbuf_init(&out, 0);
286 strbuf_addstr(&out, "Squashed commit of the following:\n");
287 while ((commit = get_revision(&rev)) != NULL) {
288 strbuf_addch(&out, '\n');
289 strbuf_addf(&out, "commit %s\n",
290 sha1_to_hex(commit->object.sha1));
291 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
292 NULL, NULL, rev.date_mode, 0);
293 }
294 write(fd, out.buf, out.len);
295 close(fd);
296 strbuf_release(&out);
297 }
298
299 static int run_hook(const char *name)
300 {
301 struct child_process hook;
302 const char *argv[3], *env[2];
303 char index[PATH_MAX];
304
305 argv[0] = git_path("hooks/%s", name);
306 if (access(argv[0], X_OK) < 0)
307 return 0;
308
309 snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
310 env[0] = index;
311 env[1] = NULL;
312
313 if (squash)
314 argv[1] = "1";
315 else
316 argv[1] = "0";
317 argv[2] = NULL;
318
319 memset(&hook, 0, sizeof(hook));
320 hook.argv = argv;
321 hook.no_stdin = 1;
322 hook.stdout_to_stderr = 1;
323 hook.env = env;
324
325 return run_command(&hook);
326 }
327
328 static void finish(const unsigned char *new_head, const char *msg)
329 {
330 struct strbuf reflog_message;
331
332 strbuf_init(&reflog_message, 0);
333 if (!msg)
334 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
335 else {
336 printf("%s\n", msg);
337 strbuf_addf(&reflog_message, "%s: %s",
338 getenv("GIT_REFLOG_ACTION"), msg);
339 }
340 if (squash) {
341 squash_message();
342 } else {
343 if (!merge_msg.len)
344 printf("No merge message -- not updating HEAD\n");
345 else {
346 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
347 update_ref(reflog_message.buf, "HEAD",
348 new_head, head, 0,
349 DIE_ON_ERR);
350 /*
351 * We ignore errors in 'gc --auto', since the
352 * user should see them.
353 */
354 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
355 }
356 }
357 if (new_head && show_diffstat) {
358 struct diff_options opts;
359 diff_setup(&opts);
360 opts.output_format |=
361 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
362 opts.detect_rename = DIFF_DETECT_RENAME;
363 if (diff_use_color_default > 0)
364 DIFF_OPT_SET(&opts, COLOR_DIFF);
365 if (diff_setup_done(&opts) < 0)
366 die("diff_setup_done failed");
367 diff_tree_sha1(head, new_head, "", &opts);
368 diffcore_std(&opts);
369 diff_flush(&opts);
370 }
371
372 /* Run a post-merge hook */
373 run_hook("post-merge");
374
375 strbuf_release(&reflog_message);
376 }
377
378 /* Get the name for the merge commit's message. */
379 static void merge_name(const char *remote, struct strbuf *msg)
380 {
381 struct object *remote_head;
382 unsigned char branch_head[20], buf_sha[20];
383 struct strbuf buf;
384 const char *ptr;
385 int len, early;
386
387 memset(branch_head, 0, sizeof(branch_head));
388 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
389 if (!remote_head)
390 die("'%s' does not point to a commit", remote);
391
392 strbuf_init(&buf, 0);
393 strbuf_addstr(&buf, "refs/heads/");
394 strbuf_addstr(&buf, remote);
395 resolve_ref(buf.buf, branch_head, 0, 0);
396
397 if (!hashcmp(remote_head->sha1, branch_head)) {
398 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
399 sha1_to_hex(branch_head), remote);
400 return;
401 }
402
403 /* See if remote matches <name>^^^.. or <name>~<number> */
404 for (len = 0, ptr = remote + strlen(remote);
405 remote < ptr && ptr[-1] == '^';
406 ptr--)
407 len++;
408 if (len)
409 early = 1;
410 else {
411 early = 0;
412 ptr = strrchr(remote, '~');
413 if (ptr) {
414 int seen_nonzero = 0;
415
416 len++; /* count ~ */
417 while (*++ptr && isdigit(*ptr)) {
418 seen_nonzero |= (*ptr != '0');
419 len++;
420 }
421 if (*ptr)
422 len = 0; /* not ...~<number> */
423 else if (seen_nonzero)
424 early = 1;
425 else if (len == 1)
426 early = 1; /* "name~" is "name~1"! */
427 }
428 }
429 if (len) {
430 struct strbuf truname = STRBUF_INIT;
431 strbuf_addstr(&truname, "refs/heads/");
432 strbuf_addstr(&truname, remote);
433 strbuf_setlen(&truname, truname.len - len);
434 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
435 strbuf_addf(msg,
436 "%s\t\tbranch '%s'%s of .\n",
437 sha1_to_hex(remote_head->sha1),
438 truname.buf + 11,
439 (early ? " (early part)" : ""));
440 return;
441 }
442 }
443
444 if (!strcmp(remote, "FETCH_HEAD") &&
445 !access(git_path("FETCH_HEAD"), R_OK)) {
446 FILE *fp;
447 struct strbuf line;
448 char *ptr;
449
450 strbuf_init(&line, 0);
451 fp = fopen(git_path("FETCH_HEAD"), "r");
452 if (!fp)
453 die("could not open %s for reading: %s",
454 git_path("FETCH_HEAD"), strerror(errno));
455 strbuf_getline(&line, fp, '\n');
456 fclose(fp);
457 ptr = strstr(line.buf, "\tnot-for-merge\t");
458 if (ptr)
459 strbuf_remove(&line, ptr-line.buf+1, 13);
460 strbuf_addbuf(msg, &line);
461 strbuf_release(&line);
462 return;
463 }
464 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
465 sha1_to_hex(remote_head->sha1), remote);
466 }
467
468 static int git_merge_config(const char *k, const char *v, void *cb)
469 {
470 if (branch && !prefixcmp(k, "branch.") &&
471 !prefixcmp(k + 7, branch) &&
472 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
473 const char **argv;
474 int argc;
475 char *buf;
476
477 buf = xstrdup(v);
478 argc = split_cmdline(buf, &argv);
479 if (argc < 0)
480 die("Bad branch.%s.mergeoptions string", branch);
481 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
482 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
483 argc++;
484 parse_options(argc, argv, builtin_merge_options,
485 builtin_merge_usage, 0);
486 free(buf);
487 }
488
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);
498 }
499
500 static int read_tree_trivial(unsigned char *common, unsigned char *head,
501 unsigned char *one)
502 {
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;
507
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);
530 }
531 if (unpack_trees(nr_trees, t, &opts))
532 return -1;
533 return 0;
534 }
535
536 static void write_tree_trivial(unsigned char *sha1)
537 {
538 if (write_cache_as_tree(sha1, 0, NULL))
539 die("git write-tree failed to write a tree");
540 }
541
542 static int try_merge_strategy(const char *strategy, struct commit_list *common,
543 const char *head_arg)
544 {
545 const char **args;
546 int i = 0, ret;
547 struct commit_list *j;
548 struct strbuf buf;
549
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;
572 }
573
574 static void count_diff_files(struct diff_queue_struct *q,
575 struct diff_options *opt, void *data)
576 {
577 int *count = data;
578
579 (*count) += q->nr;
580 }
581
582 static int count_unmerged_entries(void)
583 {
584 const struct index_state *state = &the_index;
585 int i, ret = 0;
586
587 for (i = 0; i < state->cache_nr; i++)
588 if (ce_stage(state->cache[i]))
589 ret++;
590
591 return ret;
592 }
593
594 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
595 {
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));
602
603 refresh_cache(REFRESH_QUIET);
604
605 fd = hold_locked_index(lock_file, 1);
606
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;
614
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;
622
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);
632 }
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;
639 }
640
641 static void split_merge_strategies(const char *string, struct strategy **list,
642 int *nr, int *alloc)
643 {
644 char *p, *q, *buf;
645
646 if (!string)
647 return;
648
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;
663 }
664 }
665 }
666
667 static void add_strategies(const char *string, unsigned attr)
668 {
669 struct strategy *list = NULL;
670 int list_alloc = 0, list_nr = 0, i;
671
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;
678 }
679 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
680 if (all_strategy[i].attr & attr)
681 append_strategy(&all_strategy[i]);
682
683 }
684
685 static int merge_trivial(void)
686 {
687 unsigned char result_tree[20], result_commit[20];
688 struct commit_list *parent = xmalloc(sizeof(struct commit_list *));
689
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;
700 }
701
702 static int finish_automerge(struct commit_list *common,
703 unsigned char *result_tree,
704 const char *wt_strategy)
705 {
706 struct commit_list *parents = NULL, *j;
707 struct strbuf buf = STRBUF_INIT;
708 unsigned char result_commit[20];
709
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;
717
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;
722 }
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;
731 }
732
733 static int suggest_conflicts(void)
734 {
735 FILE *fp;
736 int pos;
737
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];
744
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++;
751 }
752 }
753 fclose(fp);
754 rerere();
755 printf("Automatic merge failed; "
756 "fix conflicts and then commit the result.\n");
757 return 1;
758 }
759
760 static struct commit *is_old_style_invocation(int argc, const char **argv)
761 {
762 struct commit *second_token = NULL;
763 if (argc > 1) {
764 unsigned char second_sha1[20];
765
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;
773 }
774 return second_token;
775 }
776
777 static int evaluate_result(void)
778 {
779 int cnt = 0;
780 struct rev_info rev;
781
782 discard_cache();
783 if (read_cache() < 0)
784 die("failed to read the cache");
785
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);
794
795 /*
796 * Check how many unmerged entries are
797 * there.
798 */
799 cnt += count_unmerged_entries();
800
801 return cnt;
802 }
803
804 int cmd_merge(int argc, const char **argv, const char *prefix)
805 {
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;
814
815 setup_work_tree();
816 if (read_cache_unmerged())
817 die("You are in the middle of a conflicted merge.");
818
819 /*
820 * Check if we are _not_ on a detached HEAD, i.e. if there is a
821 * current branch.
822 */
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;
828
829 git_config(git_merge_config, NULL);
830
831 /* for color.ui */
832 if (diff_use_color_default == -1)
833 diff_use_color_default = git_use_color_default;
834
835 argc = parse_options(argc, argv, builtin_merge_options,
836 builtin_merge_usage, 0);
837
838 if (squash) {
839 if (!allow_fast_forward)
840 die("You cannot combine --squash with --no-ff.");
841 option_commit = 0;
842 }
843
844 if (!argc)
845 usage_with_options(builtin_merge_usage,
846 builtin_merge_options);
847
848 /*
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.
855 */
856 strbuf_init(&buf, 0);
857
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;
865 /*
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".
869 */
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;
887
888 /* We are invoked directly as the first-class UI. */
889 head_arg = "HEAD";
890
891 /*
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.
898 */
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);
905 }
906
907 if (head_invalid || !argc)
908 usage_with_options(builtin_merge_usage,
909 builtin_merge_options);
910
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);
916
917 for (i = 0; i < argc; i++) {
918 struct object *o;
919
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;
925
926 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
927 setenv(buf.buf, argv[i], 1);
928 strbuf_reset(&buf);
929 }
930
931 if (!use_strategies) {
932 if (!remoteheads->next)
933 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
934 else
935 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
936 }
937
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;
943 }
944
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);
953 }
954
955 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
956 DIE_ON_ERR);
957
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) {
962 /*
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.
965 */
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];
975
976 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
977
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;
991
992 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
993 return 1;
994
995 finish(o->sha1, msg.buf);
996 drop_save();
997 return 0;
998 } else if (!remoteheads->next && common->next)
999 ;
1000 /*
1001 * We are not doing octopus and not fast forward. Need
1002 * a real merge.
1003 */
1004 else if (!remoteheads->next && !common->next && option_commit) {
1005 /*
1006 * We are not doing octopus, not fast forward, and have
1007 * only one common.
1008 */
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");
1018 }
1019 } else {
1020 /*
1021 * An octopus. If we can reach all the remote we are up
1022 * to date.
1023 */
1024 int up_to_date = 1;
1025 struct commit_list *j;
1026
1027 for (j = remoteheads; j; j = j->next) {
1028 struct commit_list *common_one;
1029
1030 /*
1031 * Here we *have* to calculate the individual
1032 * merge_bases again, otherwise "git merge HEAD^
1033 * HEAD^^" would be missed.
1034 */
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;
1041 }
1042 }
1043 if (up_to_date) {
1044 finish_up_to_date("Already up-to-date. Yeeah!");
1045 return 0;
1046 }
1047 }
1048
1049 /* We are going to make a new commit. */
1050 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1051
1052 /*
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.
1059 */
1060 if (use_strategies_nr != 1) {
1061 /*
1062 * Stash away the local changes so that we can try more
1063 * than one.
1064 */
1065 save_state();
1066 } else {
1067 memcpy(stash, null_sha1, 20);
1068 }
1069
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();
1075 }
1076 if (use_strategies_nr != 1)
1077 printf("Trying merge strategy %s...\n",
1078 use_strategies[i]->name);
1079 /*
1080 * Remember which strategy left the state in the working
1081 * tree.
1082 */
1083 wt_strategy = use_strategies[i]->name;
1084
1085 ret = try_merge_strategy(use_strategies[i]->name,
1086 common, head_arg);
1087 if (!option_commit && !ret) {
1088 merge_was_ok = 1;
1089 /*
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.
1093 */
1094 ret = 1;
1095 }
1096
1097 if (ret) {
1098 /*
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.
1102 */
1103 if (ret == 1) {
1104 int cnt = evaluate_result();
1105
1106 if (best_cnt <= 0 || cnt <= best_cnt) {
1107 best_strategy = use_strategies[i]->name;
1108 best_cnt = cnt;
1109 }
1110 }
1111 if (merge_was_ok)
1112 break;
1113 else
1114 continue;
1115 }
1116
1117 /* Automerge succeeded. */
1118 discard_cache();
1119 write_tree_trivial(result_tree);
1120 automerge_was_ok = 1;
1121 break;
1122 }
1123
1124 /*
1125 * If we have a resulting tree, that means the strategy module
1126 * auto resolved the merge cleanly.
1127 */
1128 if (automerge_was_ok)
1129 return finish_automerge(common, result_tree, wt_strategy);
1130
1131 /*
1132 * Pick the result from the best strategy and have the user fix
1133 * it up.
1134 */
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);
1152 }
1153
1154 if (squash)
1155 finish(NULL, NULL);
1156 else {
1157 int fd;
1158 struct commit_list *j;
1159
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);
1178 }
1179
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();
1186 }