Merge branch 'maint-1.6.1' into 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 #include "merge-recursive.h"
27
28 #define DEFAULT_TWOHEAD (1<<0)
29 #define DEFAULT_OCTOPUS (1<<1)
30 #define NO_FAST_FORWARD (1<<2)
31 #define NO_TRIVIAL (1<<3)
32
33 struct strategy {
34 const char *name;
35 unsigned attr;
36 };
37
38 static const char * const builtin_merge_usage[] = {
39 "git merge [options] <remote>...",
40 "git merge [options] <msg> HEAD <remote>",
41 NULL
42 };
43
44 static int show_diffstat = 1, option_log, squash;
45 static int option_commit = 1, allow_fast_forward = 1;
46 static int allow_trivial = 1, have_message;
47 static struct strbuf merge_msg;
48 static struct commit_list *remoteheads;
49 static unsigned char head[20], stash[20];
50 static struct strategy **use_strategies;
51 static size_t use_strategies_nr, use_strategies_alloc;
52 static const char *branch;
53 static int verbosity;
54
55 static struct strategy all_strategy[] = {
56 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
57 { "octopus", DEFAULT_OCTOPUS },
58 { "resolve", 0 },
59 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
60 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
61 };
62
63 static const char *pull_twohead, *pull_octopus;
64
65 static int option_parse_message(const struct option *opt,
66 const char *arg, int unset)
67 {
68 struct strbuf *buf = opt->value;
69
70 if (unset)
71 strbuf_setlen(buf, 0);
72 else if (arg) {
73 strbuf_addf(buf, "%s\n\n", arg);
74 have_message = 1;
75 } else
76 return error("switch `m' requires a value");
77 return 0;
78 }
79
80 static struct strategy *get_strategy(const char *name)
81 {
82 int i;
83 struct strategy *ret;
84 static struct cmdnames main_cmds, other_cmds;
85 static int loaded;
86
87 if (!name)
88 return NULL;
89
90 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
91 if (!strcmp(name, all_strategy[i].name))
92 return &all_strategy[i];
93
94 if (!loaded) {
95 struct cmdnames not_strategies;
96 loaded = 1;
97
98 memset(&not_strategies, 0, sizeof(struct cmdnames));
99 load_command_list("git-merge-", &main_cmds, &other_cmds);
100 for (i = 0; i < main_cmds.cnt; i++) {
101 int j, found = 0;
102 struct cmdname *ent = main_cmds.names[i];
103 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
104 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
105 && !all_strategy[j].name[ent->len])
106 found = 1;
107 if (!found)
108 add_cmdname(&not_strategies, ent->name, ent->len);
109 exclude_cmds(&main_cmds, &not_strategies);
110 }
111 }
112 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
113 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
114 fprintf(stderr, "Available strategies are:");
115 for (i = 0; i < main_cmds.cnt; i++)
116 fprintf(stderr, " %s", main_cmds.names[i]->name);
117 fprintf(stderr, ".\n");
118 if (other_cmds.cnt) {
119 fprintf(stderr, "Available custom strategies are:");
120 for (i = 0; i < other_cmds.cnt; i++)
121 fprintf(stderr, " %s", other_cmds.names[i]->name);
122 fprintf(stderr, ".\n");
123 }
124 exit(1);
125 }
126
127 ret = xcalloc(1, sizeof(struct strategy));
128 ret->name = xstrdup(name);
129 return ret;
130 }
131
132 static void append_strategy(struct strategy *s)
133 {
134 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
135 use_strategies[use_strategies_nr++] = s;
136 }
137
138 static int option_parse_strategy(const struct option *opt,
139 const char *name, int unset)
140 {
141 if (unset)
142 return 0;
143
144 append_strategy(get_strategy(name));
145 return 0;
146 }
147
148 static int option_parse_n(const struct option *opt,
149 const char *arg, int unset)
150 {
151 show_diffstat = unset;
152 return 0;
153 }
154
155 static struct option builtin_merge_options[] = {
156 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
157 "do not show a diffstat at the end of the merge",
158 PARSE_OPT_NOARG, option_parse_n },
159 OPT_BOOLEAN(0, "stat", &show_diffstat,
160 "show a diffstat at the end of the merge"),
161 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
162 OPT_BOOLEAN(0, "log", &option_log,
163 "add list of one-line log to merge commit message"),
164 OPT_BOOLEAN(0, "squash", &squash,
165 "create a single commit instead of doing a merge"),
166 OPT_BOOLEAN(0, "commit", &option_commit,
167 "perform a commit if the merge succeeds (default)"),
168 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
169 "allow fast forward (default)"),
170 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
171 "merge strategy to use", option_parse_strategy),
172 OPT_CALLBACK('m', "message", &merge_msg, "message",
173 "message to be used for the merge commit (if any)",
174 option_parse_message),
175 OPT__VERBOSITY(&verbosity),
176 OPT_END()
177 };
178
179 /* Cleans up metadata that is uninteresting after a succeeded merge. */
180 static void drop_save(void)
181 {
182 unlink(git_path("MERGE_HEAD"));
183 unlink(git_path("MERGE_MSG"));
184 unlink(git_path("MERGE_MODE"));
185 }
186
187 static void save_state(void)
188 {
189 int len;
190 struct child_process cp;
191 struct strbuf buffer = STRBUF_INIT;
192 const char *argv[] = {"stash", "create", NULL};
193
194 memset(&cp, 0, sizeof(cp));
195 cp.argv = argv;
196 cp.out = -1;
197 cp.git_cmd = 1;
198
199 if (start_command(&cp))
200 die("could not run stash.");
201 len = strbuf_read(&buffer, cp.out, 1024);
202 close(cp.out);
203
204 if (finish_command(&cp) || len < 0)
205 die("stash failed");
206 else if (!len)
207 return;
208 strbuf_setlen(&buffer, buffer.len-1);
209 if (get_sha1(buffer.buf, stash))
210 die("not a valid object: %s", buffer.buf);
211 }
212
213 static void reset_hard(unsigned const char *sha1, int verbose)
214 {
215 int i = 0;
216 const char *args[6];
217
218 args[i++] = "read-tree";
219 if (verbose)
220 args[i++] = "-v";
221 args[i++] = "--reset";
222 args[i++] = "-u";
223 args[i++] = sha1_to_hex(sha1);
224 args[i] = NULL;
225
226 if (run_command_v_opt(args, RUN_GIT_CMD))
227 die("read-tree failed");
228 }
229
230 static void restore_state(void)
231 {
232 struct strbuf sb = STRBUF_INIT;
233 const char *args[] = { "stash", "apply", NULL, NULL };
234
235 if (is_null_sha1(stash))
236 return;
237
238 reset_hard(head, 1);
239
240 args[2] = sha1_to_hex(stash);
241
242 /*
243 * It is OK to ignore error here, for example when there was
244 * nothing to restore.
245 */
246 run_command_v_opt(args, RUN_GIT_CMD);
247
248 strbuf_release(&sb);
249 refresh_cache(REFRESH_QUIET);
250 }
251
252 /* This is called when no merge was necessary. */
253 static void finish_up_to_date(const char *msg)
254 {
255 if (verbosity >= 0)
256 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
257 drop_save();
258 }
259
260 static void squash_message(void)
261 {
262 struct rev_info rev;
263 struct commit *commit;
264 struct strbuf out = STRBUF_INIT;
265 struct commit_list *j;
266 int fd;
267
268 printf("Squash commit -- not updating HEAD\n");
269 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
270 if (fd < 0)
271 die("Could not write to %s", git_path("SQUASH_MSG"));
272
273 init_revisions(&rev, NULL);
274 rev.ignore_merges = 1;
275 rev.commit_format = CMIT_FMT_MEDIUM;
276
277 commit = lookup_commit(head);
278 commit->object.flags |= UNINTERESTING;
279 add_pending_object(&rev, &commit->object, NULL);
280
281 for (j = remoteheads; j; j = j->next)
282 add_pending_object(&rev, &j->item->object, NULL);
283
284 setup_revisions(0, NULL, &rev, NULL);
285 if (prepare_revision_walk(&rev))
286 die("revision walk setup failed");
287
288 strbuf_addstr(&out, "Squashed commit of the following:\n");
289 while ((commit = get_revision(&rev)) != NULL) {
290 strbuf_addch(&out, '\n');
291 strbuf_addf(&out, "commit %s\n",
292 sha1_to_hex(commit->object.sha1));
293 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
294 NULL, NULL, rev.date_mode, 0);
295 }
296 if (write(fd, out.buf, out.len) < 0)
297 die("Writing SQUASH_MSG: %s", strerror(errno));
298 if (close(fd))
299 die("Finishing SQUASH_MSG: %s", strerror(errno));
300 strbuf_release(&out);
301 }
302
303 static void finish(const unsigned char *new_head, const char *msg)
304 {
305 struct strbuf reflog_message = STRBUF_INIT;
306
307 if (!msg)
308 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
309 else {
310 if (verbosity >= 0)
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 (verbosity >= 0 && !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(NULL, "post-merge", squash ? "1" : "0", NULL);
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 = STRBUF_INIT;
359 struct strbuf bname = STRBUF_INIT;
360 const char *ptr;
361 int len, early;
362
363 len = strlen(remote);
364 if (interpret_nth_last_branch(remote, &bname) == len)
365 remote = bname.buf;
366
367 memset(branch_head, 0, sizeof(branch_head));
368 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
369 if (!remote_head)
370 die("'%s' does not point to a commit", remote);
371
372 strbuf_addstr(&buf, "refs/heads/");
373 strbuf_addstr(&buf, remote);
374 resolve_ref(buf.buf, branch_head, 0, 0);
375
376 if (!hashcmp(remote_head->sha1, branch_head)) {
377 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
378 sha1_to_hex(branch_head), remote);
379 goto cleanup;
380 }
381
382 /* See if remote matches <name>^^^.. or <name>~<number> */
383 for (len = 0, ptr = remote + strlen(remote);
384 remote < ptr && ptr[-1] == '^';
385 ptr--)
386 len++;
387 if (len)
388 early = 1;
389 else {
390 early = 0;
391 ptr = strrchr(remote, '~');
392 if (ptr) {
393 int seen_nonzero = 0;
394
395 len++; /* count ~ */
396 while (*++ptr && isdigit(*ptr)) {
397 seen_nonzero |= (*ptr != '0');
398 len++;
399 }
400 if (*ptr)
401 len = 0; /* not ...~<number> */
402 else if (seen_nonzero)
403 early = 1;
404 else if (len == 1)
405 early = 1; /* "name~" is "name~1"! */
406 }
407 }
408 if (len) {
409 struct strbuf truname = STRBUF_INIT;
410 strbuf_addstr(&truname, "refs/heads/");
411 strbuf_addstr(&truname, remote);
412 strbuf_setlen(&truname, truname.len - len);
413 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
414 strbuf_addf(msg,
415 "%s\t\tbranch '%s'%s of .\n",
416 sha1_to_hex(remote_head->sha1),
417 truname.buf + 11,
418 (early ? " (early part)" : ""));
419 strbuf_release(&truname);
420 goto cleanup;
421 }
422 }
423
424 if (!strcmp(remote, "FETCH_HEAD") &&
425 !access(git_path("FETCH_HEAD"), R_OK)) {
426 FILE *fp;
427 struct strbuf line = STRBUF_INIT;
428 char *ptr;
429
430 fp = fopen(git_path("FETCH_HEAD"), "r");
431 if (!fp)
432 die("could not open %s for reading: %s",
433 git_path("FETCH_HEAD"), strerror(errno));
434 strbuf_getline(&line, fp, '\n');
435 fclose(fp);
436 ptr = strstr(line.buf, "\tnot-for-merge\t");
437 if (ptr)
438 strbuf_remove(&line, ptr-line.buf+1, 13);
439 strbuf_addbuf(msg, &line);
440 strbuf_release(&line);
441 goto cleanup;
442 }
443 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
444 sha1_to_hex(remote_head->sha1), remote);
445 cleanup:
446 strbuf_release(&buf);
447 strbuf_release(&bname);
448 }
449
450 static int git_merge_config(const char *k, const char *v, void *cb)
451 {
452 if (branch && !prefixcmp(k, "branch.") &&
453 !prefixcmp(k + 7, branch) &&
454 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
455 const char **argv;
456 int argc;
457 char *buf;
458
459 buf = xstrdup(v);
460 argc = split_cmdline(buf, &argv);
461 if (argc < 0)
462 die("Bad branch.%s.mergeoptions string", branch);
463 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
464 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
465 argc++;
466 parse_options(argc, argv, builtin_merge_options,
467 builtin_merge_usage, 0);
468 free(buf);
469 }
470
471 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
472 show_diffstat = git_config_bool(k, v);
473 else if (!strcmp(k, "pull.twohead"))
474 return git_config_string(&pull_twohead, k, v);
475 else if (!strcmp(k, "pull.octopus"))
476 return git_config_string(&pull_octopus, k, v);
477 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
478 option_log = git_config_bool(k, v);
479 return git_diff_ui_config(k, v, cb);
480 }
481
482 static int read_tree_trivial(unsigned char *common, unsigned char *head,
483 unsigned char *one)
484 {
485 int i, nr_trees = 0;
486 struct tree *trees[MAX_UNPACK_TREES];
487 struct tree_desc t[MAX_UNPACK_TREES];
488 struct unpack_trees_options opts;
489
490 memset(&opts, 0, sizeof(opts));
491 opts.head_idx = 2;
492 opts.src_index = &the_index;
493 opts.dst_index = &the_index;
494 opts.update = 1;
495 opts.verbose_update = 1;
496 opts.trivial_merges_only = 1;
497 opts.merge = 1;
498 trees[nr_trees] = parse_tree_indirect(common);
499 if (!trees[nr_trees++])
500 return -1;
501 trees[nr_trees] = parse_tree_indirect(head);
502 if (!trees[nr_trees++])
503 return -1;
504 trees[nr_trees] = parse_tree_indirect(one);
505 if (!trees[nr_trees++])
506 return -1;
507 opts.fn = threeway_merge;
508 cache_tree_free(&active_cache_tree);
509 for (i = 0; i < nr_trees; i++) {
510 parse_tree(trees[i]);
511 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
512 }
513 if (unpack_trees(nr_trees, t, &opts))
514 return -1;
515 return 0;
516 }
517
518 static void write_tree_trivial(unsigned char *sha1)
519 {
520 if (write_cache_as_tree(sha1, 0, NULL))
521 die("git write-tree failed to write a tree");
522 }
523
524 static int try_merge_strategy(const char *strategy, struct commit_list *common,
525 const char *head_arg)
526 {
527 const char **args;
528 int i = 0, ret;
529 struct commit_list *j;
530 struct strbuf buf = STRBUF_INIT;
531 int index_fd;
532 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
533
534 index_fd = hold_locked_index(lock, 1);
535 refresh_cache(REFRESH_QUIET);
536 if (active_cache_changed &&
537 (write_cache(index_fd, active_cache, active_nr) ||
538 commit_locked_index(lock)))
539 return error("Unable to write index.");
540 rollback_lock_file(lock);
541
542 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
543 int clean;
544 struct commit *result;
545 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
546 int index_fd;
547 struct commit_list *reversed = NULL;
548 struct merge_options o;
549
550 if (remoteheads->next) {
551 error("Not handling anything other than two heads merge.");
552 return 2;
553 }
554
555 init_merge_options(&o);
556 if (!strcmp(strategy, "subtree"))
557 o.subtree_merge = 1;
558
559 o.branch1 = head_arg;
560 o.branch2 = remoteheads->item->util;
561
562 for (j = common; j; j = j->next)
563 commit_list_insert(j->item, &reversed);
564
565 index_fd = hold_locked_index(lock, 1);
566 clean = merge_recursive(&o, lookup_commit(head),
567 remoteheads->item, reversed, &result);
568 if (active_cache_changed &&
569 (write_cache(index_fd, active_cache, active_nr) ||
570 commit_locked_index(lock)))
571 die ("unable to write %s", get_index_file());
572 rollback_lock_file(lock);
573 return clean ? 0 : 1;
574 } else {
575 args = xmalloc((4 + commit_list_count(common) +
576 commit_list_count(remoteheads)) * sizeof(char *));
577 strbuf_addf(&buf, "merge-%s", strategy);
578 args[i++] = buf.buf;
579 for (j = common; j; j = j->next)
580 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
581 args[i++] = "--";
582 args[i++] = head_arg;
583 for (j = remoteheads; j; j = j->next)
584 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
585 args[i] = NULL;
586 ret = run_command_v_opt(args, RUN_GIT_CMD);
587 strbuf_release(&buf);
588 i = 1;
589 for (j = common; j; j = j->next)
590 free((void *)args[i++]);
591 i += 2;
592 for (j = remoteheads; j; j = j->next)
593 free((void *)args[i++]);
594 free(args);
595 discard_cache();
596 if (read_cache() < 0)
597 die("failed to read the cache");
598 return -ret;
599 }
600 }
601
602 static void count_diff_files(struct diff_queue_struct *q,
603 struct diff_options *opt, void *data)
604 {
605 int *count = data;
606
607 (*count) += q->nr;
608 }
609
610 static int count_unmerged_entries(void)
611 {
612 const struct index_state *state = &the_index;
613 int i, ret = 0;
614
615 for (i = 0; i < state->cache_nr; i++)
616 if (ce_stage(state->cache[i]))
617 ret++;
618
619 return ret;
620 }
621
622 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
623 {
624 struct tree *trees[MAX_UNPACK_TREES];
625 struct unpack_trees_options opts;
626 struct tree_desc t[MAX_UNPACK_TREES];
627 int i, fd, nr_trees = 0;
628 struct dir_struct dir;
629 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
630
631 refresh_cache(REFRESH_QUIET);
632
633 fd = hold_locked_index(lock_file, 1);
634
635 memset(&trees, 0, sizeof(trees));
636 memset(&opts, 0, sizeof(opts));
637 memset(&t, 0, sizeof(t));
638 memset(&dir, 0, sizeof(dir));
639 dir.show_ignored = 1;
640 dir.exclude_per_dir = ".gitignore";
641 opts.dir = &dir;
642
643 opts.head_idx = 1;
644 opts.src_index = &the_index;
645 opts.dst_index = &the_index;
646 opts.update = 1;
647 opts.verbose_update = 1;
648 opts.merge = 1;
649 opts.fn = twoway_merge;
650
651 trees[nr_trees] = parse_tree_indirect(head);
652 if (!trees[nr_trees++])
653 return -1;
654 trees[nr_trees] = parse_tree_indirect(remote);
655 if (!trees[nr_trees++])
656 return -1;
657 for (i = 0; i < nr_trees; i++) {
658 parse_tree(trees[i]);
659 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
660 }
661 if (unpack_trees(nr_trees, t, &opts))
662 return -1;
663 if (write_cache(fd, active_cache, active_nr) ||
664 commit_locked_index(lock_file))
665 die("unable to write new index file");
666 return 0;
667 }
668
669 static void split_merge_strategies(const char *string, struct strategy **list,
670 int *nr, int *alloc)
671 {
672 char *p, *q, *buf;
673
674 if (!string)
675 return;
676
677 buf = xstrdup(string);
678 q = buf;
679 for (;;) {
680 p = strchr(q, ' ');
681 if (!p) {
682 ALLOC_GROW(*list, *nr + 1, *alloc);
683 (*list)[(*nr)++].name = xstrdup(q);
684 free(buf);
685 return;
686 } else {
687 *p = '\0';
688 ALLOC_GROW(*list, *nr + 1, *alloc);
689 (*list)[(*nr)++].name = xstrdup(q);
690 q = ++p;
691 }
692 }
693 }
694
695 static void add_strategies(const char *string, unsigned attr)
696 {
697 struct strategy *list = NULL;
698 int list_alloc = 0, list_nr = 0, i;
699
700 memset(&list, 0, sizeof(list));
701 split_merge_strategies(string, &list, &list_nr, &list_alloc);
702 if (list) {
703 for (i = 0; i < list_nr; i++)
704 append_strategy(get_strategy(list[i].name));
705 return;
706 }
707 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
708 if (all_strategy[i].attr & attr)
709 append_strategy(&all_strategy[i]);
710
711 }
712
713 static int merge_trivial(void)
714 {
715 unsigned char result_tree[20], result_commit[20];
716 struct commit_list *parent = xmalloc(sizeof(*parent));
717
718 write_tree_trivial(result_tree);
719 printf("Wonderful.\n");
720 parent->item = lookup_commit(head);
721 parent->next = xmalloc(sizeof(*parent->next));
722 parent->next->item = remoteheads->item;
723 parent->next->next = NULL;
724 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
725 finish(result_commit, "In-index merge");
726 drop_save();
727 return 0;
728 }
729
730 static int finish_automerge(struct commit_list *common,
731 unsigned char *result_tree,
732 const char *wt_strategy)
733 {
734 struct commit_list *parents = NULL, *j;
735 struct strbuf buf = STRBUF_INIT;
736 unsigned char result_commit[20];
737
738 free_commit_list(common);
739 if (allow_fast_forward) {
740 parents = remoteheads;
741 commit_list_insert(lookup_commit(head), &parents);
742 parents = reduce_heads(parents);
743 } else {
744 struct commit_list **pptr = &parents;
745
746 pptr = &commit_list_insert(lookup_commit(head),
747 pptr)->next;
748 for (j = remoteheads; j; j = j->next)
749 pptr = &commit_list_insert(j->item, pptr)->next;
750 }
751 free_commit_list(remoteheads);
752 strbuf_addch(&merge_msg, '\n');
753 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
754 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
755 finish(result_commit, buf.buf);
756 strbuf_release(&buf);
757 drop_save();
758 return 0;
759 }
760
761 static int suggest_conflicts(void)
762 {
763 FILE *fp;
764 int pos;
765
766 fp = fopen(git_path("MERGE_MSG"), "a");
767 if (!fp)
768 die("Could not open %s for writing", git_path("MERGE_MSG"));
769 fprintf(fp, "\nConflicts:\n");
770 for (pos = 0; pos < active_nr; pos++) {
771 struct cache_entry *ce = active_cache[pos];
772
773 if (ce_stage(ce)) {
774 fprintf(fp, "\t%s\n", ce->name);
775 while (pos + 1 < active_nr &&
776 !strcmp(ce->name,
777 active_cache[pos + 1]->name))
778 pos++;
779 }
780 }
781 fclose(fp);
782 rerere();
783 printf("Automatic merge failed; "
784 "fix conflicts and then commit the result.\n");
785 return 1;
786 }
787
788 static struct commit *is_old_style_invocation(int argc, const char **argv)
789 {
790 struct commit *second_token = NULL;
791 if (argc > 1) {
792 unsigned char second_sha1[20];
793
794 if (get_sha1(argv[1], second_sha1))
795 return NULL;
796 second_token = lookup_commit_reference_gently(second_sha1, 0);
797 if (!second_token)
798 die("'%s' is not a commit", argv[1]);
799 if (hashcmp(second_token->object.sha1, head))
800 return NULL;
801 }
802 return second_token;
803 }
804
805 static int evaluate_result(void)
806 {
807 int cnt = 0;
808 struct rev_info rev;
809
810 /* Check how many files differ. */
811 init_revisions(&rev, "");
812 setup_revisions(0, NULL, &rev, NULL);
813 rev.diffopt.output_format |=
814 DIFF_FORMAT_CALLBACK;
815 rev.diffopt.format_callback = count_diff_files;
816 rev.diffopt.format_callback_data = &cnt;
817 run_diff_files(&rev, 0);
818
819 /*
820 * Check how many unmerged entries are
821 * there.
822 */
823 cnt += count_unmerged_entries();
824
825 return cnt;
826 }
827
828 int cmd_merge(int argc, const char **argv, const char *prefix)
829 {
830 unsigned char result_tree[20];
831 struct strbuf buf = STRBUF_INIT;
832 const char *head_arg;
833 int flag, head_invalid = 0, i;
834 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
835 struct commit_list *common = NULL;
836 const char *best_strategy = NULL, *wt_strategy = NULL;
837 struct commit_list **remotes = &remoteheads;
838
839 setup_work_tree();
840 if (read_cache_unmerged())
841 die("You are in the middle of a conflicted merge.");
842
843 /*
844 * Check if we are _not_ on a detached HEAD, i.e. if there is a
845 * current branch.
846 */
847 branch = resolve_ref("HEAD", head, 0, &flag);
848 if (branch && !prefixcmp(branch, "refs/heads/"))
849 branch += 11;
850 if (is_null_sha1(head))
851 head_invalid = 1;
852
853 git_config(git_merge_config, NULL);
854
855 /* for color.ui */
856 if (diff_use_color_default == -1)
857 diff_use_color_default = git_use_color_default;
858
859 argc = parse_options(argc, argv, builtin_merge_options,
860 builtin_merge_usage, 0);
861 if (verbosity < 0)
862 show_diffstat = 0;
863
864 if (squash) {
865 if (!allow_fast_forward)
866 die("You cannot combine --squash with --no-ff.");
867 option_commit = 0;
868 }
869
870 if (!argc)
871 usage_with_options(builtin_merge_usage,
872 builtin_merge_options);
873
874 /*
875 * This could be traditional "merge <msg> HEAD <commit>..." and
876 * the way we can tell it is to see if the second token is HEAD,
877 * but some people might have misused the interface and used a
878 * committish that is the same as HEAD there instead.
879 * Traditional format never would have "-m" so it is an
880 * additional safety measure to check for it.
881 */
882
883 if (!have_message && is_old_style_invocation(argc, argv)) {
884 strbuf_addstr(&merge_msg, argv[0]);
885 head_arg = argv[1];
886 argv += 2;
887 argc -= 2;
888 } else if (head_invalid) {
889 struct object *remote_head;
890 /*
891 * If the merged head is a valid one there is no reason
892 * to forbid "git merge" into a branch yet to be born.
893 * We do the same for "git pull".
894 */
895 if (argc != 1)
896 die("Can merge only exactly one commit into "
897 "empty head");
898 if (squash)
899 die("Squash commit into empty head not supported yet");
900 if (!allow_fast_forward)
901 die("Non-fast-forward commit does not make sense into "
902 "an empty head");
903 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
904 if (!remote_head)
905 die("%s - not something we can merge", argv[0]);
906 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
907 DIE_ON_ERR);
908 reset_hard(remote_head->sha1, 0);
909 return 0;
910 } else {
911 struct strbuf msg = STRBUF_INIT;
912
913 /* We are invoked directly as the first-class UI. */
914 head_arg = "HEAD";
915
916 /*
917 * All the rest are the commits being merged;
918 * prepare the standard merge summary message to
919 * be appended to the given message. If remote
920 * is invalid we will die later in the common
921 * codepath so we discard the error in this
922 * loop.
923 */
924 for (i = 0; i < argc; i++)
925 merge_name(argv[i], &msg);
926 fmt_merge_msg(option_log, &msg, &merge_msg);
927 if (merge_msg.len)
928 strbuf_setlen(&merge_msg, merge_msg.len-1);
929 }
930
931 if (head_invalid || !argc)
932 usage_with_options(builtin_merge_usage,
933 builtin_merge_options);
934
935 strbuf_addstr(&buf, "merge");
936 for (i = 0; i < argc; i++)
937 strbuf_addf(&buf, " %s", argv[i]);
938 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
939 strbuf_reset(&buf);
940
941 for (i = 0; i < argc; i++) {
942 struct object *o;
943 struct commit *commit;
944
945 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
946 if (!o)
947 die("%s - not something we can merge", argv[i]);
948 commit = lookup_commit(o->sha1);
949 commit->util = (void *)argv[i];
950 remotes = &commit_list_insert(commit, remotes)->next;
951
952 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
953 setenv(buf.buf, argv[i], 1);
954 strbuf_reset(&buf);
955 }
956
957 if (!use_strategies) {
958 if (!remoteheads->next)
959 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
960 else
961 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
962 }
963
964 for (i = 0; i < use_strategies_nr; i++) {
965 if (use_strategies[i]->attr & NO_FAST_FORWARD)
966 allow_fast_forward = 0;
967 if (use_strategies[i]->attr & NO_TRIVIAL)
968 allow_trivial = 0;
969 }
970
971 if (!remoteheads->next)
972 common = get_merge_bases(lookup_commit(head),
973 remoteheads->item, 1);
974 else {
975 struct commit_list *list = remoteheads;
976 commit_list_insert(lookup_commit(head), &list);
977 common = get_octopus_merge_bases(list);
978 free(list);
979 }
980
981 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
982 DIE_ON_ERR);
983
984 if (!common)
985 ; /* No common ancestors found. We need a real merge. */
986 else if (!remoteheads->next && !common->next &&
987 common->item == remoteheads->item) {
988 /*
989 * If head can reach all the merge then we are up to date.
990 * but first the most common case of merging one remote.
991 */
992 finish_up_to_date("Already up-to-date.");
993 return 0;
994 } else if (allow_fast_forward && !remoteheads->next &&
995 !common->next &&
996 !hashcmp(common->item->object.sha1, head)) {
997 /* Again the most common case of merging one remote. */
998 struct strbuf msg = STRBUF_INIT;
999 struct object *o;
1000 char hex[41];
1001
1002 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1003
1004 if (verbosity >= 0)
1005 printf("Updating %s..%s\n",
1006 hex,
1007 find_unique_abbrev(remoteheads->item->object.sha1,
1008 DEFAULT_ABBREV));
1009 strbuf_addstr(&msg, "Fast forward");
1010 if (have_message)
1011 strbuf_addstr(&msg,
1012 " (no commit created; -m option ignored)");
1013 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1014 0, NULL, OBJ_COMMIT);
1015 if (!o)
1016 return 1;
1017
1018 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1019 return 1;
1020
1021 finish(o->sha1, msg.buf);
1022 drop_save();
1023 return 0;
1024 } else if (!remoteheads->next && common->next)
1025 ;
1026 /*
1027 * We are not doing octopus and not fast forward. Need
1028 * a real merge.
1029 */
1030 else if (!remoteheads->next && !common->next && option_commit) {
1031 /*
1032 * We are not doing octopus, not fast forward, and have
1033 * only one common.
1034 */
1035 refresh_cache(REFRESH_QUIET);
1036 if (allow_trivial) {
1037 /* See if it is really trivial. */
1038 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1039 printf("Trying really trivial in-index merge...\n");
1040 if (!read_tree_trivial(common->item->object.sha1,
1041 head, remoteheads->item->object.sha1))
1042 return merge_trivial();
1043 printf("Nope.\n");
1044 }
1045 } else {
1046 /*
1047 * An octopus. If we can reach all the remote we are up
1048 * to date.
1049 */
1050 int up_to_date = 1;
1051 struct commit_list *j;
1052
1053 for (j = remoteheads; j; j = j->next) {
1054 struct commit_list *common_one;
1055
1056 /*
1057 * Here we *have* to calculate the individual
1058 * merge_bases again, otherwise "git merge HEAD^
1059 * HEAD^^" would be missed.
1060 */
1061 common_one = get_merge_bases(lookup_commit(head),
1062 j->item, 1);
1063 if (hashcmp(common_one->item->object.sha1,
1064 j->item->object.sha1)) {
1065 up_to_date = 0;
1066 break;
1067 }
1068 }
1069 if (up_to_date) {
1070 finish_up_to_date("Already up-to-date. Yeeah!");
1071 return 0;
1072 }
1073 }
1074
1075 /* We are going to make a new commit. */
1076 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1077
1078 /*
1079 * At this point, we need a real merge. No matter what strategy
1080 * we use, it would operate on the index, possibly affecting the
1081 * working tree, and when resolved cleanly, have the desired
1082 * tree in the index -- this means that the index must be in
1083 * sync with the head commit. The strategies are responsible
1084 * to ensure this.
1085 */
1086 if (use_strategies_nr != 1) {
1087 /*
1088 * Stash away the local changes so that we can try more
1089 * than one.
1090 */
1091 save_state();
1092 } else {
1093 memcpy(stash, null_sha1, 20);
1094 }
1095
1096 for (i = 0; i < use_strategies_nr; i++) {
1097 int ret;
1098 if (i) {
1099 printf("Rewinding the tree to pristine...\n");
1100 restore_state();
1101 }
1102 if (use_strategies_nr != 1)
1103 printf("Trying merge strategy %s...\n",
1104 use_strategies[i]->name);
1105 /*
1106 * Remember which strategy left the state in the working
1107 * tree.
1108 */
1109 wt_strategy = use_strategies[i]->name;
1110
1111 ret = try_merge_strategy(use_strategies[i]->name,
1112 common, head_arg);
1113 if (!option_commit && !ret) {
1114 merge_was_ok = 1;
1115 /*
1116 * This is necessary here just to avoid writing
1117 * the tree, but later we will *not* exit with
1118 * status code 1 because merge_was_ok is set.
1119 */
1120 ret = 1;
1121 }
1122
1123 if (ret) {
1124 /*
1125 * The backend exits with 1 when conflicts are
1126 * left to be resolved, with 2 when it does not
1127 * handle the given merge at all.
1128 */
1129 if (ret == 1) {
1130 int cnt = evaluate_result();
1131
1132 if (best_cnt <= 0 || cnt <= best_cnt) {
1133 best_strategy = use_strategies[i]->name;
1134 best_cnt = cnt;
1135 }
1136 }
1137 if (merge_was_ok)
1138 break;
1139 else
1140 continue;
1141 }
1142
1143 /* Automerge succeeded. */
1144 write_tree_trivial(result_tree);
1145 automerge_was_ok = 1;
1146 break;
1147 }
1148
1149 /*
1150 * If we have a resulting tree, that means the strategy module
1151 * auto resolved the merge cleanly.
1152 */
1153 if (automerge_was_ok)
1154 return finish_automerge(common, result_tree, wt_strategy);
1155
1156 /*
1157 * Pick the result from the best strategy and have the user fix
1158 * it up.
1159 */
1160 if (!best_strategy) {
1161 restore_state();
1162 if (use_strategies_nr > 1)
1163 fprintf(stderr,
1164 "No merge strategy handled the merge.\n");
1165 else
1166 fprintf(stderr, "Merge with strategy %s failed.\n",
1167 use_strategies[0]->name);
1168 return 2;
1169 } else if (best_strategy == wt_strategy)
1170 ; /* We already have its result in the working tree. */
1171 else {
1172 printf("Rewinding the tree to pristine...\n");
1173 restore_state();
1174 printf("Using the %s to prepare resolving by hand.\n",
1175 best_strategy);
1176 try_merge_strategy(best_strategy, common, head_arg);
1177 }
1178
1179 if (squash)
1180 finish(NULL, NULL);
1181 else {
1182 int fd;
1183 struct commit_list *j;
1184
1185 for (j = remoteheads; j; j = j->next)
1186 strbuf_addf(&buf, "%s\n",
1187 sha1_to_hex(j->item->object.sha1));
1188 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1189 if (fd < 0)
1190 die("Could open %s for writing",
1191 git_path("MERGE_HEAD"));
1192 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1193 die("Could not write to %s", git_path("MERGE_HEAD"));
1194 close(fd);
1195 strbuf_addch(&merge_msg, '\n');
1196 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1197 if (fd < 0)
1198 die("Could open %s for writing", git_path("MERGE_MSG"));
1199 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1200 merge_msg.len)
1201 die("Could not write to %s", git_path("MERGE_MSG"));
1202 close(fd);
1203 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1204 if (fd < 0)
1205 die("Could open %s for writing", git_path("MERGE_MODE"));
1206 strbuf_reset(&buf);
1207 if (!allow_fast_forward)
1208 strbuf_addf(&buf, "no-ff");
1209 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1210 die("Could not write to %s", git_path("MERGE_MODE"));
1211 close(fd);
1212 }
1213
1214 if (merge_was_ok) {
1215 fprintf(stderr, "Automatic merge went well; "
1216 "stopped before committing as requested\n");
1217 return 0;
1218 } else
1219 return suggest_conflicts();
1220 }