resolve-undo: record resolved conflicts in a new index extension section
[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 #include "resolve-undo.h"
28
29 #define DEFAULT_TWOHEAD (1<<0)
30 #define DEFAULT_OCTOPUS (1<<1)
31 #define NO_FAST_FORWARD (1<<2)
32 #define NO_TRIVIAL (1<<3)
33
34 struct strategy {
35 const char *name;
36 unsigned attr;
37 };
38
39 static const char * const builtin_merge_usage[] = {
40 "git merge [options] <remote>...",
41 "git merge [options] <msg> HEAD <remote>",
42 NULL
43 };
44
45 static int show_diffstat = 1, option_log, squash;
46 static int option_commit = 1, allow_fast_forward = 1;
47 static int fast_forward_only;
48 static int allow_trivial = 1, have_message;
49 static struct strbuf merge_msg;
50 static struct commit_list *remoteheads;
51 static unsigned char head[20], stash[20];
52 static struct strategy **use_strategies;
53 static size_t use_strategies_nr, use_strategies_alloc;
54 static const char *branch;
55 static int verbosity;
56
57 static struct strategy all_strategy[] = {
58 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
59 { "octopus", DEFAULT_OCTOPUS },
60 { "resolve", 0 },
61 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
62 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
63 };
64
65 static const char *pull_twohead, *pull_octopus;
66
67 static int option_parse_message(const struct option *opt,
68 const char *arg, int unset)
69 {
70 struct strbuf *buf = opt->value;
71
72 if (unset)
73 strbuf_setlen(buf, 0);
74 else if (arg) {
75 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
76 have_message = 1;
77 } else
78 return error("switch `m' requires a value");
79 return 0;
80 }
81
82 static struct strategy *get_strategy(const char *name)
83 {
84 int i;
85 struct strategy *ret;
86 static struct cmdnames main_cmds, other_cmds;
87 static int loaded;
88
89 if (!name)
90 return NULL;
91
92 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
93 if (!strcmp(name, all_strategy[i].name))
94 return &all_strategy[i];
95
96 if (!loaded) {
97 struct cmdnames not_strategies;
98 loaded = 1;
99
100 memset(&not_strategies, 0, sizeof(struct cmdnames));
101 load_command_list("git-merge-", &main_cmds, &other_cmds);
102 for (i = 0; i < main_cmds.cnt; i++) {
103 int j, found = 0;
104 struct cmdname *ent = main_cmds.names[i];
105 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
106 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
107 && !all_strategy[j].name[ent->len])
108 found = 1;
109 if (!found)
110 add_cmdname(&not_strategies, ent->name, ent->len);
111 }
112 exclude_cmds(&main_cmds, &not_strategies);
113 }
114 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
115 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
116 fprintf(stderr, "Available strategies are:");
117 for (i = 0; i < main_cmds.cnt; i++)
118 fprintf(stderr, " %s", main_cmds.names[i]->name);
119 fprintf(stderr, ".\n");
120 if (other_cmds.cnt) {
121 fprintf(stderr, "Available custom strategies are:");
122 for (i = 0; i < other_cmds.cnt; i++)
123 fprintf(stderr, " %s", other_cmds.names[i]->name);
124 fprintf(stderr, ".\n");
125 }
126 exit(1);
127 }
128
129 ret = xcalloc(1, sizeof(struct strategy));
130 ret->name = xstrdup(name);
131 return ret;
132 }
133
134 static void append_strategy(struct strategy *s)
135 {
136 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
137 use_strategies[use_strategies_nr++] = s;
138 }
139
140 static int option_parse_strategy(const struct option *opt,
141 const char *name, int unset)
142 {
143 if (unset)
144 return 0;
145
146 append_strategy(get_strategy(name));
147 return 0;
148 }
149
150 static int option_parse_n(const struct option *opt,
151 const char *arg, int unset)
152 {
153 show_diffstat = unset;
154 return 0;
155 }
156
157 static struct option builtin_merge_options[] = {
158 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
159 "do not show a diffstat at the end of the merge",
160 PARSE_OPT_NOARG, option_parse_n },
161 OPT_BOOLEAN(0, "stat", &show_diffstat,
162 "show a diffstat at the end of the merge"),
163 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
164 OPT_BOOLEAN(0, "log", &option_log,
165 "add list of one-line log to merge commit message"),
166 OPT_BOOLEAN(0, "squash", &squash,
167 "create a single commit instead of doing a merge"),
168 OPT_BOOLEAN(0, "commit", &option_commit,
169 "perform a commit if the merge succeeds (default)"),
170 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
171 "allow fast-forward (default)"),
172 OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
173 "abort if fast-forward is not possible"),
174 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
175 "merge strategy to use", option_parse_strategy),
176 OPT_CALLBACK('m', "message", &merge_msg, "message",
177 "message to be used for the merge commit (if any)",
178 option_parse_message),
179 OPT__VERBOSITY(&verbosity),
180 OPT_END()
181 };
182
183 /* Cleans up metadata that is uninteresting after a succeeded merge. */
184 static void drop_save(void)
185 {
186 unlink(git_path("MERGE_HEAD"));
187 unlink(git_path("MERGE_MSG"));
188 unlink(git_path("MERGE_MODE"));
189 }
190
191 static void save_state(void)
192 {
193 int len;
194 struct child_process cp;
195 struct strbuf buffer = STRBUF_INIT;
196 const char *argv[] = {"stash", "create", NULL};
197
198 memset(&cp, 0, sizeof(cp));
199 cp.argv = argv;
200 cp.out = -1;
201 cp.git_cmd = 1;
202
203 if (start_command(&cp))
204 die("could not run stash.");
205 len = strbuf_read(&buffer, cp.out, 1024);
206 close(cp.out);
207
208 if (finish_command(&cp) || len < 0)
209 die("stash failed");
210 else if (!len)
211 return;
212 strbuf_setlen(&buffer, buffer.len-1);
213 if (get_sha1(buffer.buf, stash))
214 die("not a valid object: %s", buffer.buf);
215 }
216
217 static void reset_hard(unsigned const char *sha1, int verbose)
218 {
219 int i = 0;
220 const char *args[6];
221
222 args[i++] = "read-tree";
223 if (verbose)
224 args[i++] = "-v";
225 args[i++] = "--reset";
226 args[i++] = "-u";
227 args[i++] = sha1_to_hex(sha1);
228 args[i] = NULL;
229
230 if (run_command_v_opt(args, RUN_GIT_CMD))
231 die("read-tree failed");
232 }
233
234 static void restore_state(void)
235 {
236 struct strbuf sb = STRBUF_INIT;
237 const char *args[] = { "stash", "apply", NULL, NULL };
238
239 if (is_null_sha1(stash))
240 return;
241
242 reset_hard(head, 1);
243
244 args[2] = sha1_to_hex(stash);
245
246 /*
247 * It is OK to ignore error here, for example when there was
248 * nothing to restore.
249 */
250 run_command_v_opt(args, RUN_GIT_CMD);
251
252 strbuf_release(&sb);
253 refresh_cache(REFRESH_QUIET);
254 }
255
256 /* This is called when no merge was necessary. */
257 static void finish_up_to_date(const char *msg)
258 {
259 if (verbosity >= 0)
260 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
261 drop_save();
262 }
263
264 static void squash_message(void)
265 {
266 struct rev_info rev;
267 struct commit *commit;
268 struct strbuf out = STRBUF_INIT;
269 struct commit_list *j;
270 int fd;
271 struct pretty_print_context ctx = {0};
272
273 printf("Squash commit -- not updating HEAD\n");
274 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
275 if (fd < 0)
276 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
277
278 init_revisions(&rev, NULL);
279 rev.ignore_merges = 1;
280 rev.commit_format = CMIT_FMT_MEDIUM;
281
282 commit = lookup_commit(head);
283 commit->object.flags |= UNINTERESTING;
284 add_pending_object(&rev, &commit->object, NULL);
285
286 for (j = remoteheads; j; j = j->next)
287 add_pending_object(&rev, &j->item->object, NULL);
288
289 setup_revisions(0, NULL, &rev, NULL);
290 if (prepare_revision_walk(&rev))
291 die("revision walk setup failed");
292
293 ctx.abbrev = rev.abbrev;
294 ctx.date_mode = rev.date_mode;
295
296 strbuf_addstr(&out, "Squashed commit of the following:\n");
297 while ((commit = get_revision(&rev)) != NULL) {
298 strbuf_addch(&out, '\n');
299 strbuf_addf(&out, "commit %s\n",
300 sha1_to_hex(commit->object.sha1));
301 pretty_print_commit(rev.commit_format, commit, &out, &ctx);
302 }
303 if (write(fd, out.buf, out.len) < 0)
304 die_errno("Writing SQUASH_MSG");
305 if (close(fd))
306 die_errno("Finishing SQUASH_MSG");
307 strbuf_release(&out);
308 }
309
310 static void finish(const unsigned char *new_head, const char *msg)
311 {
312 struct strbuf reflog_message = STRBUF_INIT;
313
314 if (!msg)
315 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
316 else {
317 if (verbosity >= 0)
318 printf("%s\n", msg);
319 strbuf_addf(&reflog_message, "%s: %s",
320 getenv("GIT_REFLOG_ACTION"), msg);
321 }
322 if (squash) {
323 squash_message();
324 } else {
325 if (verbosity >= 0 && !merge_msg.len)
326 printf("No merge message -- not updating HEAD\n");
327 else {
328 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
329 update_ref(reflog_message.buf, "HEAD",
330 new_head, head, 0,
331 DIE_ON_ERR);
332 /*
333 * We ignore errors in 'gc --auto', since the
334 * user should see them.
335 */
336 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
337 }
338 }
339 if (new_head && show_diffstat) {
340 struct diff_options opts;
341 diff_setup(&opts);
342 opts.output_format |=
343 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
344 opts.detect_rename = DIFF_DETECT_RENAME;
345 if (diff_use_color_default > 0)
346 DIFF_OPT_SET(&opts, COLOR_DIFF);
347 if (diff_setup_done(&opts) < 0)
348 die("diff_setup_done failed");
349 diff_tree_sha1(head, new_head, "", &opts);
350 diffcore_std(&opts);
351 diff_flush(&opts);
352 }
353
354 /* Run a post-merge hook */
355 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
356
357 strbuf_release(&reflog_message);
358 }
359
360 /* Get the name for the merge commit's message. */
361 static void merge_name(const char *remote, struct strbuf *msg)
362 {
363 struct object *remote_head;
364 unsigned char branch_head[20], buf_sha[20];
365 struct strbuf buf = STRBUF_INIT;
366 struct strbuf bname = STRBUF_INIT;
367 const char *ptr;
368 char *found_ref;
369 int len, early;
370
371 strbuf_branchname(&bname, remote);
372 remote = bname.buf;
373
374 memset(branch_head, 0, sizeof(branch_head));
375 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
376 if (!remote_head)
377 die("'%s' does not point to a commit", remote);
378
379 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
380 if (!prefixcmp(found_ref, "refs/heads/")) {
381 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
382 sha1_to_hex(branch_head), remote);
383 goto cleanup;
384 }
385 if (!prefixcmp(found_ref, "refs/remotes/")) {
386 strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
387 sha1_to_hex(branch_head), remote);
388 goto cleanup;
389 }
390 }
391
392 /* See if remote matches <name>^^^.. or <name>~<number> */
393 for (len = 0, ptr = remote + strlen(remote);
394 remote < ptr && ptr[-1] == '^';
395 ptr--)
396 len++;
397 if (len)
398 early = 1;
399 else {
400 early = 0;
401 ptr = strrchr(remote, '~');
402 if (ptr) {
403 int seen_nonzero = 0;
404
405 len++; /* count ~ */
406 while (*++ptr && isdigit(*ptr)) {
407 seen_nonzero |= (*ptr != '0');
408 len++;
409 }
410 if (*ptr)
411 len = 0; /* not ...~<number> */
412 else if (seen_nonzero)
413 early = 1;
414 else if (len == 1)
415 early = 1; /* "name~" is "name~1"! */
416 }
417 }
418 if (len) {
419 struct strbuf truname = STRBUF_INIT;
420 strbuf_addstr(&truname, "refs/heads/");
421 strbuf_addstr(&truname, remote);
422 strbuf_setlen(&truname, truname.len - len);
423 if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
424 strbuf_addf(msg,
425 "%s\t\tbranch '%s'%s of .\n",
426 sha1_to_hex(remote_head->sha1),
427 truname.buf + 11,
428 (early ? " (early part)" : ""));
429 strbuf_release(&truname);
430 goto cleanup;
431 }
432 }
433
434 if (!strcmp(remote, "FETCH_HEAD") &&
435 !access(git_path("FETCH_HEAD"), R_OK)) {
436 FILE *fp;
437 struct strbuf line = STRBUF_INIT;
438 char *ptr;
439
440 fp = fopen(git_path("FETCH_HEAD"), "r");
441 if (!fp)
442 die_errno("could not open '%s' for reading",
443 git_path("FETCH_HEAD"));
444 strbuf_getline(&line, fp, '\n');
445 fclose(fp);
446 ptr = strstr(line.buf, "\tnot-for-merge\t");
447 if (ptr)
448 strbuf_remove(&line, ptr-line.buf+1, 13);
449 strbuf_addbuf(msg, &line);
450 strbuf_release(&line);
451 goto cleanup;
452 }
453 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
454 sha1_to_hex(remote_head->sha1), remote);
455 cleanup:
456 strbuf_release(&buf);
457 strbuf_release(&bname);
458 }
459
460 static int git_merge_config(const char *k, const char *v, void *cb)
461 {
462 if (branch && !prefixcmp(k, "branch.") &&
463 !prefixcmp(k + 7, branch) &&
464 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
465 const char **argv;
466 int argc;
467 char *buf;
468
469 buf = xstrdup(v);
470 argc = split_cmdline(buf, &argv);
471 if (argc < 0)
472 die("Bad branch.%s.mergeoptions string", branch);
473 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
474 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
475 argc++;
476 parse_options(argc, argv, NULL, builtin_merge_options,
477 builtin_merge_usage, 0);
478 free(buf);
479 }
480
481 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
482 show_diffstat = git_config_bool(k, v);
483 else if (!strcmp(k, "pull.twohead"))
484 return git_config_string(&pull_twohead, k, v);
485 else if (!strcmp(k, "pull.octopus"))
486 return git_config_string(&pull_octopus, k, v);
487 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
488 option_log = git_config_bool(k, v);
489 return git_diff_ui_config(k, v, cb);
490 }
491
492 static int read_tree_trivial(unsigned char *common, unsigned char *head,
493 unsigned char *one)
494 {
495 int i, nr_trees = 0;
496 struct tree *trees[MAX_UNPACK_TREES];
497 struct tree_desc t[MAX_UNPACK_TREES];
498 struct unpack_trees_options opts;
499
500 memset(&opts, 0, sizeof(opts));
501 opts.head_idx = 2;
502 opts.src_index = &the_index;
503 opts.dst_index = &the_index;
504 opts.update = 1;
505 opts.verbose_update = 1;
506 opts.trivial_merges_only = 1;
507 opts.merge = 1;
508 trees[nr_trees] = parse_tree_indirect(common);
509 if (!trees[nr_trees++])
510 return -1;
511 trees[nr_trees] = parse_tree_indirect(head);
512 if (!trees[nr_trees++])
513 return -1;
514 trees[nr_trees] = parse_tree_indirect(one);
515 if (!trees[nr_trees++])
516 return -1;
517 opts.fn = threeway_merge;
518 cache_tree_free(&active_cache_tree);
519 for (i = 0; i < nr_trees; i++) {
520 parse_tree(trees[i]);
521 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
522 }
523 if (unpack_trees(nr_trees, t, &opts))
524 return -1;
525 return 0;
526 }
527
528 static void write_tree_trivial(unsigned char *sha1)
529 {
530 if (write_cache_as_tree(sha1, 0, NULL))
531 die("git write-tree failed to write a tree");
532 }
533
534 static int try_merge_strategy(const char *strategy, struct commit_list *common,
535 const char *head_arg)
536 {
537 const char **args;
538 int i = 0, ret;
539 struct commit_list *j;
540 struct strbuf buf = STRBUF_INIT;
541 int index_fd;
542 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
543
544 index_fd = hold_locked_index(lock, 1);
545 refresh_cache(REFRESH_QUIET);
546 if (active_cache_changed &&
547 (write_cache(index_fd, active_cache, active_nr) ||
548 commit_locked_index(lock)))
549 return error("Unable to write index.");
550 rollback_lock_file(lock);
551
552 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
553 int clean;
554 struct commit *result;
555 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
556 int index_fd;
557 struct commit_list *reversed = NULL;
558 struct merge_options o;
559
560 if (remoteheads->next) {
561 error("Not handling anything other than two heads merge.");
562 return 2;
563 }
564
565 init_merge_options(&o);
566 if (!strcmp(strategy, "subtree"))
567 o.subtree_merge = 1;
568
569 o.branch1 = head_arg;
570 o.branch2 = remoteheads->item->util;
571
572 for (j = common; j; j = j->next)
573 commit_list_insert(j->item, &reversed);
574
575 index_fd = hold_locked_index(lock, 1);
576 clean = merge_recursive(&o, lookup_commit(head),
577 remoteheads->item, reversed, &result);
578 if (active_cache_changed &&
579 (write_cache(index_fd, active_cache, active_nr) ||
580 commit_locked_index(lock)))
581 die ("unable to write %s", get_index_file());
582 rollback_lock_file(lock);
583 return clean ? 0 : 1;
584 } else {
585 args = xmalloc((4 + commit_list_count(common) +
586 commit_list_count(remoteheads)) * sizeof(char *));
587 strbuf_addf(&buf, "merge-%s", strategy);
588 args[i++] = buf.buf;
589 for (j = common; j; j = j->next)
590 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
591 args[i++] = "--";
592 args[i++] = head_arg;
593 for (j = remoteheads; j; j = j->next)
594 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
595 args[i] = NULL;
596 ret = run_command_v_opt(args, RUN_GIT_CMD);
597 strbuf_release(&buf);
598 i = 1;
599 for (j = common; j; j = j->next)
600 free((void *)args[i++]);
601 i += 2;
602 for (j = remoteheads; j; j = j->next)
603 free((void *)args[i++]);
604 free(args);
605 discard_cache();
606 if (read_cache() < 0)
607 die("failed to read the cache");
608 resolve_undo_clear();
609 return ret;
610 }
611 }
612
613 static void count_diff_files(struct diff_queue_struct *q,
614 struct diff_options *opt, void *data)
615 {
616 int *count = data;
617
618 (*count) += q->nr;
619 }
620
621 static int count_unmerged_entries(void)
622 {
623 int i, ret = 0;
624
625 for (i = 0; i < active_nr; i++)
626 if (ce_stage(active_cache[i]))
627 ret++;
628
629 return ret;
630 }
631
632 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
633 {
634 struct tree *trees[MAX_UNPACK_TREES];
635 struct unpack_trees_options opts;
636 struct tree_desc t[MAX_UNPACK_TREES];
637 int i, fd, nr_trees = 0;
638 struct dir_struct dir;
639 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
640
641 refresh_cache(REFRESH_QUIET);
642
643 fd = hold_locked_index(lock_file, 1);
644
645 memset(&trees, 0, sizeof(trees));
646 memset(&opts, 0, sizeof(opts));
647 memset(&t, 0, sizeof(t));
648 memset(&dir, 0, sizeof(dir));
649 dir.flags |= DIR_SHOW_IGNORED;
650 dir.exclude_per_dir = ".gitignore";
651 opts.dir = &dir;
652
653 opts.head_idx = 1;
654 opts.src_index = &the_index;
655 opts.dst_index = &the_index;
656 opts.update = 1;
657 opts.verbose_update = 1;
658 opts.merge = 1;
659 opts.fn = twoway_merge;
660 opts.msgs = get_porcelain_error_msgs();
661
662 trees[nr_trees] = parse_tree_indirect(head);
663 if (!trees[nr_trees++])
664 return -1;
665 trees[nr_trees] = parse_tree_indirect(remote);
666 if (!trees[nr_trees++])
667 return -1;
668 for (i = 0; i < nr_trees; i++) {
669 parse_tree(trees[i]);
670 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
671 }
672 if (unpack_trees(nr_trees, t, &opts))
673 return -1;
674 if (write_cache(fd, active_cache, active_nr) ||
675 commit_locked_index(lock_file))
676 die("unable to write new index file");
677 return 0;
678 }
679
680 static void split_merge_strategies(const char *string, struct strategy **list,
681 int *nr, int *alloc)
682 {
683 char *p, *q, *buf;
684
685 if (!string)
686 return;
687
688 buf = xstrdup(string);
689 q = buf;
690 for (;;) {
691 p = strchr(q, ' ');
692 if (!p) {
693 ALLOC_GROW(*list, *nr + 1, *alloc);
694 (*list)[(*nr)++].name = xstrdup(q);
695 free(buf);
696 return;
697 } else {
698 *p = '\0';
699 ALLOC_GROW(*list, *nr + 1, *alloc);
700 (*list)[(*nr)++].name = xstrdup(q);
701 q = ++p;
702 }
703 }
704 }
705
706 static void add_strategies(const char *string, unsigned attr)
707 {
708 struct strategy *list = NULL;
709 int list_alloc = 0, list_nr = 0, i;
710
711 memset(&list, 0, sizeof(list));
712 split_merge_strategies(string, &list, &list_nr, &list_alloc);
713 if (list) {
714 for (i = 0; i < list_nr; i++)
715 append_strategy(get_strategy(list[i].name));
716 return;
717 }
718 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
719 if (all_strategy[i].attr & attr)
720 append_strategy(&all_strategy[i]);
721
722 }
723
724 static int merge_trivial(void)
725 {
726 unsigned char result_tree[20], result_commit[20];
727 struct commit_list *parent = xmalloc(sizeof(*parent));
728
729 write_tree_trivial(result_tree);
730 printf("Wonderful.\n");
731 parent->item = lookup_commit(head);
732 parent->next = xmalloc(sizeof(*parent->next));
733 parent->next->item = remoteheads->item;
734 parent->next->next = NULL;
735 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
736 finish(result_commit, "In-index merge");
737 drop_save();
738 return 0;
739 }
740
741 static int finish_automerge(struct commit_list *common,
742 unsigned char *result_tree,
743 const char *wt_strategy)
744 {
745 struct commit_list *parents = NULL, *j;
746 struct strbuf buf = STRBUF_INIT;
747 unsigned char result_commit[20];
748
749 free_commit_list(common);
750 if (allow_fast_forward) {
751 parents = remoteheads;
752 commit_list_insert(lookup_commit(head), &parents);
753 parents = reduce_heads(parents);
754 } else {
755 struct commit_list **pptr = &parents;
756
757 pptr = &commit_list_insert(lookup_commit(head),
758 pptr)->next;
759 for (j = remoteheads; j; j = j->next)
760 pptr = &commit_list_insert(j->item, pptr)->next;
761 }
762 free_commit_list(remoteheads);
763 strbuf_addch(&merge_msg, '\n');
764 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
765 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
766 finish(result_commit, buf.buf);
767 strbuf_release(&buf);
768 drop_save();
769 return 0;
770 }
771
772 static int suggest_conflicts(void)
773 {
774 FILE *fp;
775 int pos;
776
777 fp = fopen(git_path("MERGE_MSG"), "a");
778 if (!fp)
779 die_errno("Could not open '%s' for writing",
780 git_path("MERGE_MSG"));
781 fprintf(fp, "\nConflicts:\n");
782 for (pos = 0; pos < active_nr; pos++) {
783 struct cache_entry *ce = active_cache[pos];
784
785 if (ce_stage(ce)) {
786 fprintf(fp, "\t%s\n", ce->name);
787 while (pos + 1 < active_nr &&
788 !strcmp(ce->name,
789 active_cache[pos + 1]->name))
790 pos++;
791 }
792 }
793 fclose(fp);
794 rerere();
795 printf("Automatic merge failed; "
796 "fix conflicts and then commit the result.\n");
797 return 1;
798 }
799
800 static struct commit *is_old_style_invocation(int argc, const char **argv)
801 {
802 struct commit *second_token = NULL;
803 if (argc > 2) {
804 unsigned char second_sha1[20];
805
806 if (get_sha1(argv[1], second_sha1))
807 return NULL;
808 second_token = lookup_commit_reference_gently(second_sha1, 0);
809 if (!second_token)
810 die("'%s' is not a commit", argv[1]);
811 if (hashcmp(second_token->object.sha1, head))
812 return NULL;
813 }
814 return second_token;
815 }
816
817 static int evaluate_result(void)
818 {
819 int cnt = 0;
820 struct rev_info rev;
821
822 /* Check how many files differ. */
823 init_revisions(&rev, "");
824 setup_revisions(0, NULL, &rev, NULL);
825 rev.diffopt.output_format |=
826 DIFF_FORMAT_CALLBACK;
827 rev.diffopt.format_callback = count_diff_files;
828 rev.diffopt.format_callback_data = &cnt;
829 run_diff_files(&rev, 0);
830
831 /*
832 * Check how many unmerged entries are
833 * there.
834 */
835 cnt += count_unmerged_entries();
836
837 return cnt;
838 }
839
840 int cmd_merge(int argc, const char **argv, const char *prefix)
841 {
842 unsigned char result_tree[20];
843 struct strbuf buf = STRBUF_INIT;
844 const char *head_arg;
845 int flag, head_invalid = 0, i;
846 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
847 struct commit_list *common = NULL;
848 const char *best_strategy = NULL, *wt_strategy = NULL;
849 struct commit_list **remotes = &remoteheads;
850
851 if (file_exists(git_path("MERGE_HEAD")))
852 die("You have not concluded your merge. (MERGE_HEAD exists)");
853 if (read_cache_unmerged())
854 die("You are in the middle of a conflicted merge."
855 " (index unmerged)");
856 resolve_undo_clear();
857 /*
858 * Check if we are _not_ on a detached HEAD, i.e. if there is a
859 * current branch.
860 */
861 branch = resolve_ref("HEAD", head, 0, &flag);
862 if (branch && !prefixcmp(branch, "refs/heads/"))
863 branch += 11;
864 if (is_null_sha1(head))
865 head_invalid = 1;
866
867 git_config(git_merge_config, NULL);
868
869 /* for color.ui */
870 if (diff_use_color_default == -1)
871 diff_use_color_default = git_use_color_default;
872
873 argc = parse_options(argc, argv, prefix, builtin_merge_options,
874 builtin_merge_usage, 0);
875 if (verbosity < 0)
876 show_diffstat = 0;
877
878 if (squash) {
879 if (!allow_fast_forward)
880 die("You cannot combine --squash with --no-ff.");
881 option_commit = 0;
882 }
883
884 if (!allow_fast_forward && fast_forward_only)
885 die("You cannot combine --no-ff with --ff-only.");
886
887 if (!argc)
888 usage_with_options(builtin_merge_usage,
889 builtin_merge_options);
890
891 /*
892 * This could be traditional "merge <msg> HEAD <commit>..." and
893 * the way we can tell it is to see if the second token is HEAD,
894 * but some people might have misused the interface and used a
895 * committish that is the same as HEAD there instead.
896 * Traditional format never would have "-m" so it is an
897 * additional safety measure to check for it.
898 */
899
900 if (!have_message && is_old_style_invocation(argc, argv)) {
901 strbuf_addstr(&merge_msg, argv[0]);
902 head_arg = argv[1];
903 argv += 2;
904 argc -= 2;
905 } else if (head_invalid) {
906 struct object *remote_head;
907 /*
908 * If the merged head is a valid one there is no reason
909 * to forbid "git merge" into a branch yet to be born.
910 * We do the same for "git pull".
911 */
912 if (argc != 1)
913 die("Can merge only exactly one commit into "
914 "empty head");
915 if (squash)
916 die("Squash commit into empty head not supported yet");
917 if (!allow_fast_forward)
918 die("Non-fast-forward commit does not make sense into "
919 "an empty head");
920 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
921 if (!remote_head)
922 die("%s - not something we can merge", argv[0]);
923 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
924 DIE_ON_ERR);
925 reset_hard(remote_head->sha1, 0);
926 return 0;
927 } else {
928 struct strbuf msg = STRBUF_INIT;
929
930 /* We are invoked directly as the first-class UI. */
931 head_arg = "HEAD";
932
933 /*
934 * All the rest are the commits being merged;
935 * prepare the standard merge summary message to
936 * be appended to the given message. If remote
937 * is invalid we will die later in the common
938 * codepath so we discard the error in this
939 * loop.
940 */
941 if (!have_message) {
942 for (i = 0; i < argc; i++)
943 merge_name(argv[i], &msg);
944 fmt_merge_msg(option_log, &msg, &merge_msg);
945 if (merge_msg.len)
946 strbuf_setlen(&merge_msg, merge_msg.len-1);
947 }
948 }
949
950 if (head_invalid || !argc)
951 usage_with_options(builtin_merge_usage,
952 builtin_merge_options);
953
954 strbuf_addstr(&buf, "merge");
955 for (i = 0; i < argc; i++)
956 strbuf_addf(&buf, " %s", argv[i]);
957 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
958 strbuf_reset(&buf);
959
960 for (i = 0; i < argc; i++) {
961 struct object *o;
962 struct commit *commit;
963
964 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
965 if (!o)
966 die("%s - not something we can merge", argv[i]);
967 commit = lookup_commit(o->sha1);
968 commit->util = (void *)argv[i];
969 remotes = &commit_list_insert(commit, remotes)->next;
970
971 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
972 setenv(buf.buf, argv[i], 1);
973 strbuf_reset(&buf);
974 }
975
976 if (!use_strategies) {
977 if (!remoteheads->next)
978 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
979 else
980 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
981 }
982
983 for (i = 0; i < use_strategies_nr; i++) {
984 if (use_strategies[i]->attr & NO_FAST_FORWARD)
985 allow_fast_forward = 0;
986 if (use_strategies[i]->attr & NO_TRIVIAL)
987 allow_trivial = 0;
988 }
989
990 if (!remoteheads->next)
991 common = get_merge_bases(lookup_commit(head),
992 remoteheads->item, 1);
993 else {
994 struct commit_list *list = remoteheads;
995 commit_list_insert(lookup_commit(head), &list);
996 common = get_octopus_merge_bases(list);
997 free(list);
998 }
999
1000 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1001 DIE_ON_ERR);
1002
1003 if (!common)
1004 ; /* No common ancestors found. We need a real merge. */
1005 else if (!remoteheads->next && !common->next &&
1006 common->item == remoteheads->item) {
1007 /*
1008 * If head can reach all the merge then we are up to date.
1009 * but first the most common case of merging one remote.
1010 */
1011 finish_up_to_date("Already up-to-date.");
1012 return 0;
1013 } else if (allow_fast_forward && !remoteheads->next &&
1014 !common->next &&
1015 !hashcmp(common->item->object.sha1, head)) {
1016 /* Again the most common case of merging one remote. */
1017 struct strbuf msg = STRBUF_INIT;
1018 struct object *o;
1019 char hex[41];
1020
1021 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1022
1023 if (verbosity >= 0)
1024 printf("Updating %s..%s\n",
1025 hex,
1026 find_unique_abbrev(remoteheads->item->object.sha1,
1027 DEFAULT_ABBREV));
1028 strbuf_addstr(&msg, "Fast-forward");
1029 if (have_message)
1030 strbuf_addstr(&msg,
1031 " (no commit created; -m option ignored)");
1032 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1033 0, NULL, OBJ_COMMIT);
1034 if (!o)
1035 return 1;
1036
1037 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1038 return 1;
1039
1040 finish(o->sha1, msg.buf);
1041 drop_save();
1042 return 0;
1043 } else if (!remoteheads->next && common->next)
1044 ;
1045 /*
1046 * We are not doing octopus and not fast-forward. Need
1047 * a real merge.
1048 */
1049 else if (!remoteheads->next && !common->next && option_commit) {
1050 /*
1051 * We are not doing octopus, not fast-forward, and have
1052 * only one common.
1053 */
1054 refresh_cache(REFRESH_QUIET);
1055 if (allow_trivial && !fast_forward_only) {
1056 /* See if it is really trivial. */
1057 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1058 printf("Trying really trivial in-index merge...\n");
1059 if (!read_tree_trivial(common->item->object.sha1,
1060 head, remoteheads->item->object.sha1))
1061 return merge_trivial();
1062 printf("Nope.\n");
1063 }
1064 } else {
1065 /*
1066 * An octopus. If we can reach all the remote we are up
1067 * to date.
1068 */
1069 int up_to_date = 1;
1070 struct commit_list *j;
1071
1072 for (j = remoteheads; j; j = j->next) {
1073 struct commit_list *common_one;
1074
1075 /*
1076 * Here we *have* to calculate the individual
1077 * merge_bases again, otherwise "git merge HEAD^
1078 * HEAD^^" would be missed.
1079 */
1080 common_one = get_merge_bases(lookup_commit(head),
1081 j->item, 1);
1082 if (hashcmp(common_one->item->object.sha1,
1083 j->item->object.sha1)) {
1084 up_to_date = 0;
1085 break;
1086 }
1087 }
1088 if (up_to_date) {
1089 finish_up_to_date("Already up-to-date. Yeeah!");
1090 return 0;
1091 }
1092 }
1093
1094 if (fast_forward_only)
1095 die("Not possible to fast-forward, aborting.");
1096
1097 /* We are going to make a new commit. */
1098 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1099
1100 /*
1101 * At this point, we need a real merge. No matter what strategy
1102 * we use, it would operate on the index, possibly affecting the
1103 * working tree, and when resolved cleanly, have the desired
1104 * tree in the index -- this means that the index must be in
1105 * sync with the head commit. The strategies are responsible
1106 * to ensure this.
1107 */
1108 if (use_strategies_nr != 1) {
1109 /*
1110 * Stash away the local changes so that we can try more
1111 * than one.
1112 */
1113 save_state();
1114 } else {
1115 memcpy(stash, null_sha1, 20);
1116 }
1117
1118 for (i = 0; i < use_strategies_nr; i++) {
1119 int ret;
1120 if (i) {
1121 printf("Rewinding the tree to pristine...\n");
1122 restore_state();
1123 }
1124 if (use_strategies_nr != 1)
1125 printf("Trying merge strategy %s...\n",
1126 use_strategies[i]->name);
1127 /*
1128 * Remember which strategy left the state in the working
1129 * tree.
1130 */
1131 wt_strategy = use_strategies[i]->name;
1132
1133 ret = try_merge_strategy(use_strategies[i]->name,
1134 common, head_arg);
1135 if (!option_commit && !ret) {
1136 merge_was_ok = 1;
1137 /*
1138 * This is necessary here just to avoid writing
1139 * the tree, but later we will *not* exit with
1140 * status code 1 because merge_was_ok is set.
1141 */
1142 ret = 1;
1143 }
1144
1145 if (ret) {
1146 /*
1147 * The backend exits with 1 when conflicts are
1148 * left to be resolved, with 2 when it does not
1149 * handle the given merge at all.
1150 */
1151 if (ret == 1) {
1152 int cnt = evaluate_result();
1153
1154 if (best_cnt <= 0 || cnt <= best_cnt) {
1155 best_strategy = use_strategies[i]->name;
1156 best_cnt = cnt;
1157 }
1158 }
1159 if (merge_was_ok)
1160 break;
1161 else
1162 continue;
1163 }
1164
1165 /* Automerge succeeded. */
1166 write_tree_trivial(result_tree);
1167 automerge_was_ok = 1;
1168 break;
1169 }
1170
1171 /*
1172 * If we have a resulting tree, that means the strategy module
1173 * auto resolved the merge cleanly.
1174 */
1175 if (automerge_was_ok)
1176 return finish_automerge(common, result_tree, wt_strategy);
1177
1178 /*
1179 * Pick the result from the best strategy and have the user fix
1180 * it up.
1181 */
1182 if (!best_strategy) {
1183 restore_state();
1184 if (use_strategies_nr > 1)
1185 fprintf(stderr,
1186 "No merge strategy handled the merge.\n");
1187 else
1188 fprintf(stderr, "Merge with strategy %s failed.\n",
1189 use_strategies[0]->name);
1190 return 2;
1191 } else if (best_strategy == wt_strategy)
1192 ; /* We already have its result in the working tree. */
1193 else {
1194 printf("Rewinding the tree to pristine...\n");
1195 restore_state();
1196 printf("Using the %s to prepare resolving by hand.\n",
1197 best_strategy);
1198 try_merge_strategy(best_strategy, common, head_arg);
1199 }
1200
1201 if (squash)
1202 finish(NULL, NULL);
1203 else {
1204 int fd;
1205 struct commit_list *j;
1206
1207 for (j = remoteheads; j; j = j->next)
1208 strbuf_addf(&buf, "%s\n",
1209 sha1_to_hex(j->item->object.sha1));
1210 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1211 if (fd < 0)
1212 die_errno("Could not open '%s' for writing",
1213 git_path("MERGE_HEAD"));
1214 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1215 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1216 close(fd);
1217 strbuf_addch(&merge_msg, '\n');
1218 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1219 if (fd < 0)
1220 die_errno("Could not open '%s' for writing",
1221 git_path("MERGE_MSG"));
1222 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1223 merge_msg.len)
1224 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1225 close(fd);
1226 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1227 if (fd < 0)
1228 die_errno("Could not open '%s' for writing",
1229 git_path("MERGE_MODE"));
1230 strbuf_reset(&buf);
1231 if (!allow_fast_forward)
1232 strbuf_addf(&buf, "no-ff");
1233 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1234 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1235 close(fd);
1236 }
1237
1238 if (merge_was_ok) {
1239 fprintf(stderr, "Automatic merge went well; "
1240 "stopped before committing as requested\n");
1241 return 0;
1242 } else
1243 return suggest_conflicts();
1244 }