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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 **xopts;
55 static size_t xopts_nr, xopts_alloc;
56 static const char *branch;
57 static int verbosity;
58 static int allow_rerere_auto;
59
60 static struct strategy all_strategy[] = {
61 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
62 { "octopus", DEFAULT_OCTOPUS },
63 { "resolve", 0 },
64 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
65 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
66 };
67
68 static const char *pull_twohead, *pull_octopus;
69
70 static int option_parse_message(const struct option *opt,
71 const char *arg, int unset)
72 {
73 struct strbuf *buf = opt->value;
74
75 if (unset)
76 strbuf_setlen(buf, 0);
77 else if (arg) {
78 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
79 have_message = 1;
80 } else
81 return error("switch `m' requires a value");
82 return 0;
83 }
84
85 static struct strategy *get_strategy(const char *name)
86 {
87 int i;
88 struct strategy *ret;
89 static struct cmdnames main_cmds, other_cmds;
90 static int loaded;
91
92 if (!name)
93 return NULL;
94
95 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
96 if (!strcmp(name, all_strategy[i].name))
97 return &all_strategy[i];
98
99 if (!loaded) {
100 struct cmdnames not_strategies;
101 loaded = 1;
102
103 memset(&not_strategies, 0, sizeof(struct cmdnames));
104 load_command_list("git-merge-", &main_cmds, &other_cmds);
105 for (i = 0; i < main_cmds.cnt; i++) {
106 int j, found = 0;
107 struct cmdname *ent = main_cmds.names[i];
108 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
109 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
110 && !all_strategy[j].name[ent->len])
111 found = 1;
112 if (!found)
113 add_cmdname(&not_strategies, ent->name, ent->len);
114 }
115 exclude_cmds(&main_cmds, &not_strategies);
116 }
117 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
118 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
119 fprintf(stderr, "Available strategies are:");
120 for (i = 0; i < main_cmds.cnt; i++)
121 fprintf(stderr, " %s", main_cmds.names[i]->name);
122 fprintf(stderr, ".\n");
123 if (other_cmds.cnt) {
124 fprintf(stderr, "Available custom strategies are:");
125 for (i = 0; i < other_cmds.cnt; i++)
126 fprintf(stderr, " %s", other_cmds.names[i]->name);
127 fprintf(stderr, ".\n");
128 }
129 exit(1);
130 }
131
132 ret = xcalloc(1, sizeof(struct strategy));
133 ret->name = xstrdup(name);
134 return ret;
135 }
136
137 static void append_strategy(struct strategy *s)
138 {
139 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
140 use_strategies[use_strategies_nr++] = s;
141 }
142
143 static int option_parse_strategy(const struct option *opt,
144 const char *name, int unset)
145 {
146 if (unset)
147 return 0;
148
149 append_strategy(get_strategy(name));
150 return 0;
151 }
152
153 static int option_parse_x(const struct option *opt,
154 const char *arg, int unset)
155 {
156 if (unset)
157 return 0;
158
159 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
160 xopts[xopts_nr++] = xstrdup(arg);
161 return 0;
162 }
163
164 static int option_parse_n(const struct option *opt,
165 const char *arg, int unset)
166 {
167 show_diffstat = unset;
168 return 0;
169 }
170
171 static struct option builtin_merge_options[] = {
172 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
173 "do not show a diffstat at the end of the merge",
174 PARSE_OPT_NOARG, option_parse_n },
175 OPT_BOOLEAN(0, "stat", &show_diffstat,
176 "show a diffstat at the end of the merge"),
177 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
178 OPT_BOOLEAN(0, "log", &option_log,
179 "add list of one-line log to merge commit message"),
180 OPT_BOOLEAN(0, "squash", &squash,
181 "create a single commit instead of doing a merge"),
182 OPT_BOOLEAN(0, "commit", &option_commit,
183 "perform a commit if the merge succeeds (default)"),
184 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
185 "allow fast-forward (default)"),
186 OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
187 "abort if fast-forward is not possible"),
188 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
189 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
190 "merge strategy to use", option_parse_strategy),
191 OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
192 "option for selected merge strategy", option_parse_x),
193 OPT_CALLBACK('m', "message", &merge_msg, "message",
194 "message to be used for the merge commit (if any)",
195 option_parse_message),
196 OPT__VERBOSITY(&verbosity),
197 OPT_END()
198 };
199
200 /* Cleans up metadata that is uninteresting after a succeeded merge. */
201 static void drop_save(void)
202 {
203 unlink(git_path("MERGE_HEAD"));
204 unlink(git_path("MERGE_MSG"));
205 unlink(git_path("MERGE_MODE"));
206 }
207
208 static void save_state(void)
209 {
210 int len;
211 struct child_process cp;
212 struct strbuf buffer = STRBUF_INIT;
213 const char *argv[] = {"stash", "create", NULL};
214
215 memset(&cp, 0, sizeof(cp));
216 cp.argv = argv;
217 cp.out = -1;
218 cp.git_cmd = 1;
219
220 if (start_command(&cp))
221 die("could not run stash.");
222 len = strbuf_read(&buffer, cp.out, 1024);
223 close(cp.out);
224
225 if (finish_command(&cp) || len < 0)
226 die("stash failed");
227 else if (!len)
228 return;
229 strbuf_setlen(&buffer, buffer.len-1);
230 if (get_sha1(buffer.buf, stash))
231 die("not a valid object: %s", buffer.buf);
232 }
233
234 static void reset_hard(unsigned const char *sha1, int verbose)
235 {
236 int i = 0;
237 const char *args[6];
238
239 args[i++] = "read-tree";
240 if (verbose)
241 args[i++] = "-v";
242 args[i++] = "--reset";
243 args[i++] = "-u";
244 args[i++] = sha1_to_hex(sha1);
245 args[i] = NULL;
246
247 if (run_command_v_opt(args, RUN_GIT_CMD))
248 die("read-tree failed");
249 }
250
251 static void restore_state(void)
252 {
253 struct strbuf sb = STRBUF_INIT;
254 const char *args[] = { "stash", "apply", NULL, NULL };
255
256 if (is_null_sha1(stash))
257 return;
258
259 reset_hard(head, 1);
260
261 args[2] = sha1_to_hex(stash);
262
263 /*
264 * It is OK to ignore error here, for example when there was
265 * nothing to restore.
266 */
267 run_command_v_opt(args, RUN_GIT_CMD);
268
269 strbuf_release(&sb);
270 refresh_cache(REFRESH_QUIET);
271 }
272
273 /* This is called when no merge was necessary. */
274 static void finish_up_to_date(const char *msg)
275 {
276 if (verbosity >= 0)
277 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
278 drop_save();
279 }
280
281 static void squash_message(void)
282 {
283 struct rev_info rev;
284 struct commit *commit;
285 struct strbuf out = STRBUF_INIT;
286 struct commit_list *j;
287 int fd;
288 struct pretty_print_context ctx = {0};
289
290 printf("Squash commit -- not updating HEAD\n");
291 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
292 if (fd < 0)
293 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
294
295 init_revisions(&rev, NULL);
296 rev.ignore_merges = 1;
297 rev.commit_format = CMIT_FMT_MEDIUM;
298
299 commit = lookup_commit(head);
300 commit->object.flags |= UNINTERESTING;
301 add_pending_object(&rev, &commit->object, NULL);
302
303 for (j = remoteheads; j; j = j->next)
304 add_pending_object(&rev, &j->item->object, NULL);
305
306 setup_revisions(0, NULL, &rev, NULL);
307 if (prepare_revision_walk(&rev))
308 die("revision walk setup failed");
309
310 ctx.abbrev = rev.abbrev;
311 ctx.date_mode = rev.date_mode;
312
313 strbuf_addstr(&out, "Squashed commit of the following:\n");
314 while ((commit = get_revision(&rev)) != NULL) {
315 strbuf_addch(&out, '\n');
316 strbuf_addf(&out, "commit %s\n",
317 sha1_to_hex(commit->object.sha1));
318 pretty_print_commit(rev.commit_format, commit, &out, &ctx);
319 }
320 if (write(fd, out.buf, out.len) < 0)
321 die_errno("Writing SQUASH_MSG");
322 if (close(fd))
323 die_errno("Finishing SQUASH_MSG");
324 strbuf_release(&out);
325 }
326
327 static void finish(const unsigned char *new_head, const char *msg)
328 {
329 struct strbuf reflog_message = STRBUF_INIT;
330
331 if (!msg)
332 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
333 else {
334 if (verbosity >= 0)
335 printf("%s\n", msg);
336 strbuf_addf(&reflog_message, "%s: %s",
337 getenv("GIT_REFLOG_ACTION"), msg);
338 }
339 if (squash) {
340 squash_message();
341 } else {
342 if (verbosity >= 0 && !merge_msg.len)
343 printf("No merge message -- not updating HEAD\n");
344 else {
345 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
346 update_ref(reflog_message.buf, "HEAD",
347 new_head, head, 0,
348 DIE_ON_ERR);
349 /*
350 * We ignore errors in 'gc --auto', since the
351 * user should see them.
352 */
353 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
354 }
355 }
356 if (new_head && show_diffstat) {
357 struct diff_options opts;
358 diff_setup(&opts);
359 opts.output_format |=
360 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
361 opts.detect_rename = DIFF_DETECT_RENAME;
362 if (diff_use_color_default > 0)
363 DIFF_OPT_SET(&opts, COLOR_DIFF);
364 if (diff_setup_done(&opts) < 0)
365 die("diff_setup_done failed");
366 diff_tree_sha1(head, new_head, "", &opts);
367 diffcore_std(&opts);
368 diff_flush(&opts);
369 }
370
371 /* Run a post-merge hook */
372 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
373
374 strbuf_release(&reflog_message);
375 }
376
377 /* Get the name for the merge commit's message. */
378 static void merge_name(const char *remote, struct strbuf *msg)
379 {
380 struct object *remote_head;
381 unsigned char branch_head[20], buf_sha[20];
382 struct strbuf buf = STRBUF_INIT;
383 struct strbuf bname = STRBUF_INIT;
384 const char *ptr;
385 char *found_ref;
386 int len, early;
387
388 strbuf_branchname(&bname, remote);
389 remote = bname.buf;
390
391 memset(branch_head, 0, sizeof(branch_head));
392 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
393 if (!remote_head)
394 die("'%s' does not point to a commit", remote);
395
396 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
397 if (!prefixcmp(found_ref, "refs/heads/")) {
398 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
399 sha1_to_hex(branch_head), remote);
400 goto cleanup;
401 }
402 if (!prefixcmp(found_ref, "refs/remotes/")) {
403 strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
404 sha1_to_hex(branch_head), remote);
405 goto cleanup;
406 }
407 }
408
409 /* See if remote matches <name>^^^.. or <name>~<number> */
410 for (len = 0, ptr = remote + strlen(remote);
411 remote < ptr && ptr[-1] == '^';
412 ptr--)
413 len++;
414 if (len)
415 early = 1;
416 else {
417 early = 0;
418 ptr = strrchr(remote, '~');
419 if (ptr) {
420 int seen_nonzero = 0;
421
422 len++; /* count ~ */
423 while (*++ptr && isdigit(*ptr)) {
424 seen_nonzero |= (*ptr != '0');
425 len++;
426 }
427 if (*ptr)
428 len = 0; /* not ...~<number> */
429 else if (seen_nonzero)
430 early = 1;
431 else if (len == 1)
432 early = 1; /* "name~" is "name~1"! */
433 }
434 }
435 if (len) {
436 struct strbuf truname = STRBUF_INIT;
437 strbuf_addstr(&truname, "refs/heads/");
438 strbuf_addstr(&truname, remote);
439 strbuf_setlen(&truname, truname.len - len);
440 if (resolve_ref(truname.buf, buf_sha, 0, NULL)) {
441 strbuf_addf(msg,
442 "%s\t\tbranch '%s'%s of .\n",
443 sha1_to_hex(remote_head->sha1),
444 truname.buf + 11,
445 (early ? " (early part)" : ""));
446 strbuf_release(&truname);
447 goto cleanup;
448 }
449 }
450
451 if (!strcmp(remote, "FETCH_HEAD") &&
452 !access(git_path("FETCH_HEAD"), R_OK)) {
453 FILE *fp;
454 struct strbuf line = STRBUF_INIT;
455 char *ptr;
456
457 fp = fopen(git_path("FETCH_HEAD"), "r");
458 if (!fp)
459 die_errno("could not open '%s' for reading",
460 git_path("FETCH_HEAD"));
461 strbuf_getline(&line, fp, '\n');
462 fclose(fp);
463 ptr = strstr(line.buf, "\tnot-for-merge\t");
464 if (ptr)
465 strbuf_remove(&line, ptr-line.buf+1, 13);
466 strbuf_addbuf(msg, &line);
467 strbuf_release(&line);
468 goto cleanup;
469 }
470 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
471 sha1_to_hex(remote_head->sha1), remote);
472 cleanup:
473 strbuf_release(&buf);
474 strbuf_release(&bname);
475 }
476
477 static int git_merge_config(const char *k, const char *v, void *cb)
478 {
479 if (branch && !prefixcmp(k, "branch.") &&
480 !prefixcmp(k + 7, branch) &&
481 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
482 const char **argv;
483 int argc;
484 char *buf;
485
486 buf = xstrdup(v);
487 argc = split_cmdline(buf, &argv);
488 if (argc < 0)
489 die("Bad branch.%s.mergeoptions string", branch);
490 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
491 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
492 argc++;
493 parse_options(argc, argv, NULL, builtin_merge_options,
494 builtin_merge_usage, 0);
495 free(buf);
496 }
497
498 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
499 show_diffstat = git_config_bool(k, v);
500 else if (!strcmp(k, "pull.twohead"))
501 return git_config_string(&pull_twohead, k, v);
502 else if (!strcmp(k, "pull.octopus"))
503 return git_config_string(&pull_octopus, k, v);
504 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
505 option_log = git_config_bool(k, v);
506 return git_diff_ui_config(k, v, cb);
507 }
508
509 static int read_tree_trivial(unsigned char *common, unsigned char *head,
510 unsigned char *one)
511 {
512 int i, nr_trees = 0;
513 struct tree *trees[MAX_UNPACK_TREES];
514 struct tree_desc t[MAX_UNPACK_TREES];
515 struct unpack_trees_options opts;
516
517 memset(&opts, 0, sizeof(opts));
518 opts.head_idx = 2;
519 opts.src_index = &the_index;
520 opts.dst_index = &the_index;
521 opts.update = 1;
522 opts.verbose_update = 1;
523 opts.trivial_merges_only = 1;
524 opts.merge = 1;
525 trees[nr_trees] = parse_tree_indirect(common);
526 if (!trees[nr_trees++])
527 return -1;
528 trees[nr_trees] = parse_tree_indirect(head);
529 if (!trees[nr_trees++])
530 return -1;
531 trees[nr_trees] = parse_tree_indirect(one);
532 if (!trees[nr_trees++])
533 return -1;
534 opts.fn = threeway_merge;
535 cache_tree_free(&active_cache_tree);
536 for (i = 0; i < nr_trees; i++) {
537 parse_tree(trees[i]);
538 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
539 }
540 if (unpack_trees(nr_trees, t, &opts))
541 return -1;
542 return 0;
543 }
544
545 static void write_tree_trivial(unsigned char *sha1)
546 {
547 if (write_cache_as_tree(sha1, 0, NULL))
548 die("git write-tree failed to write a tree");
549 }
550
551 static int try_merge_strategy(const char *strategy, struct commit_list *common,
552 const char *head_arg)
553 {
554 const char **args;
555 int i = 0, x = 0, ret;
556 struct commit_list *j;
557 struct strbuf buf = STRBUF_INIT;
558 int index_fd;
559 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
560
561 index_fd = hold_locked_index(lock, 1);
562 refresh_cache(REFRESH_QUIET);
563 if (active_cache_changed &&
564 (write_cache(index_fd, active_cache, active_nr) ||
565 commit_locked_index(lock)))
566 return error("Unable to write index.");
567 rollback_lock_file(lock);
568
569 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
570 int clean;
571 struct commit *result;
572 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
573 int index_fd;
574 struct commit_list *reversed = NULL;
575 struct merge_options o;
576
577 if (remoteheads->next) {
578 error("Not handling anything other than two heads merge.");
579 return 2;
580 }
581
582 init_merge_options(&o);
583 if (!strcmp(strategy, "subtree"))
584 o.subtree_shift = "";
585
586 for (x = 0; x < xopts_nr; x++) {
587 if (!strcmp(xopts[x], "ours"))
588 o.recursive_variant = MERGE_RECURSIVE_OURS;
589 else if (!strcmp(xopts[x], "theirs"))
590 o.recursive_variant = MERGE_RECURSIVE_THEIRS;
591 else if (!strcmp(xopts[x], "subtree"))
592 o.subtree_shift = "";
593 else if (!prefixcmp(xopts[x], "subtree="))
594 o.subtree_shift = xopts[x]+8;
595 else
596 die("Unknown option for merge-recursive: -X%s", xopts[x]);
597 }
598
599 o.branch1 = head_arg;
600 o.branch2 = remoteheads->item->util;
601
602 for (j = common; j; j = j->next)
603 commit_list_insert(j->item, &reversed);
604
605 index_fd = hold_locked_index(lock, 1);
606 clean = merge_recursive(&o, lookup_commit(head),
607 remoteheads->item, reversed, &result);
608 if (active_cache_changed &&
609 (write_cache(index_fd, active_cache, active_nr) ||
610 commit_locked_index(lock)))
611 die ("unable to write %s", get_index_file());
612 rollback_lock_file(lock);
613 return clean ? 0 : 1;
614 } else {
615 args = xmalloc((4 + xopts_nr + commit_list_count(common) +
616 commit_list_count(remoteheads)) * sizeof(char *));
617 strbuf_addf(&buf, "merge-%s", strategy);
618 args[i++] = buf.buf;
619 for (x = 0; x < xopts_nr; x++) {
620 char *s = xmalloc(strlen(xopts[x])+2+1);
621 strcpy(s, "--");
622 strcpy(s+2, xopts[x]);
623 args[i++] = s;
624 }
625 for (j = common; j; j = j->next)
626 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
627 args[i++] = "--";
628 args[i++] = head_arg;
629 for (j = remoteheads; j; j = j->next)
630 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
631 args[i] = NULL;
632 ret = run_command_v_opt(args, RUN_GIT_CMD);
633 strbuf_release(&buf);
634 i = 1;
635 for (x = 0; x < xopts_nr; x++)
636 free((void *)args[i++]);
637 for (j = common; j; j = j->next)
638 free((void *)args[i++]);
639 i += 2;
640 for (j = remoteheads; j; j = j->next)
641 free((void *)args[i++]);
642 free(args);
643 discard_cache();
644 if (read_cache() < 0)
645 die("failed to read the cache");
646 resolve_undo_clear();
647 return ret;
648 }
649 }
650
651 static void count_diff_files(struct diff_queue_struct *q,
652 struct diff_options *opt, void *data)
653 {
654 int *count = data;
655
656 (*count) += q->nr;
657 }
658
659 static int count_unmerged_entries(void)
660 {
661 int i, ret = 0;
662
663 for (i = 0; i < active_nr; i++)
664 if (ce_stage(active_cache[i]))
665 ret++;
666
667 return ret;
668 }
669
670 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
671 {
672 struct tree *trees[MAX_UNPACK_TREES];
673 struct unpack_trees_options opts;
674 struct tree_desc t[MAX_UNPACK_TREES];
675 int i, fd, nr_trees = 0;
676 struct dir_struct dir;
677 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
678
679 refresh_cache(REFRESH_QUIET);
680
681 fd = hold_locked_index(lock_file, 1);
682
683 memset(&trees, 0, sizeof(trees));
684 memset(&opts, 0, sizeof(opts));
685 memset(&t, 0, sizeof(t));
686 memset(&dir, 0, sizeof(dir));
687 dir.flags |= DIR_SHOW_IGNORED;
688 dir.exclude_per_dir = ".gitignore";
689 opts.dir = &dir;
690
691 opts.head_idx = 1;
692 opts.src_index = &the_index;
693 opts.dst_index = &the_index;
694 opts.update = 1;
695 opts.verbose_update = 1;
696 opts.merge = 1;
697 opts.fn = twoway_merge;
698 opts.msgs = get_porcelain_error_msgs();
699
700 trees[nr_trees] = parse_tree_indirect(head);
701 if (!trees[nr_trees++])
702 return -1;
703 trees[nr_trees] = parse_tree_indirect(remote);
704 if (!trees[nr_trees++])
705 return -1;
706 for (i = 0; i < nr_trees; i++) {
707 parse_tree(trees[i]);
708 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
709 }
710 if (unpack_trees(nr_trees, t, &opts))
711 return -1;
712 if (write_cache(fd, active_cache, active_nr) ||
713 commit_locked_index(lock_file))
714 die("unable to write new index file");
715 return 0;
716 }
717
718 static void split_merge_strategies(const char *string, struct strategy **list,
719 int *nr, int *alloc)
720 {
721 char *p, *q, *buf;
722
723 if (!string)
724 return;
725
726 buf = xstrdup(string);
727 q = buf;
728 for (;;) {
729 p = strchr(q, ' ');
730 if (!p) {
731 ALLOC_GROW(*list, *nr + 1, *alloc);
732 (*list)[(*nr)++].name = xstrdup(q);
733 free(buf);
734 return;
735 } else {
736 *p = '\0';
737 ALLOC_GROW(*list, *nr + 1, *alloc);
738 (*list)[(*nr)++].name = xstrdup(q);
739 q = ++p;
740 }
741 }
742 }
743
744 static void add_strategies(const char *string, unsigned attr)
745 {
746 struct strategy *list = NULL;
747 int list_alloc = 0, list_nr = 0, i;
748
749 memset(&list, 0, sizeof(list));
750 split_merge_strategies(string, &list, &list_nr, &list_alloc);
751 if (list) {
752 for (i = 0; i < list_nr; i++)
753 append_strategy(get_strategy(list[i].name));
754 return;
755 }
756 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
757 if (all_strategy[i].attr & attr)
758 append_strategy(&all_strategy[i]);
759
760 }
761
762 static int merge_trivial(void)
763 {
764 unsigned char result_tree[20], result_commit[20];
765 struct commit_list *parent = xmalloc(sizeof(*parent));
766
767 write_tree_trivial(result_tree);
768 printf("Wonderful.\n");
769 parent->item = lookup_commit(head);
770 parent->next = xmalloc(sizeof(*parent->next));
771 parent->next->item = remoteheads->item;
772 parent->next->next = NULL;
773 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
774 finish(result_commit, "In-index merge");
775 drop_save();
776 return 0;
777 }
778
779 static int finish_automerge(struct commit_list *common,
780 unsigned char *result_tree,
781 const char *wt_strategy)
782 {
783 struct commit_list *parents = NULL, *j;
784 struct strbuf buf = STRBUF_INIT;
785 unsigned char result_commit[20];
786
787 free_commit_list(common);
788 if (allow_fast_forward) {
789 parents = remoteheads;
790 commit_list_insert(lookup_commit(head), &parents);
791 parents = reduce_heads(parents);
792 } else {
793 struct commit_list **pptr = &parents;
794
795 pptr = &commit_list_insert(lookup_commit(head),
796 pptr)->next;
797 for (j = remoteheads; j; j = j->next)
798 pptr = &commit_list_insert(j->item, pptr)->next;
799 }
800 free_commit_list(remoteheads);
801 strbuf_addch(&merge_msg, '\n');
802 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
803 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
804 finish(result_commit, buf.buf);
805 strbuf_release(&buf);
806 drop_save();
807 return 0;
808 }
809
810 static int suggest_conflicts(void)
811 {
812 FILE *fp;
813 int pos;
814
815 fp = fopen(git_path("MERGE_MSG"), "a");
816 if (!fp)
817 die_errno("Could not open '%s' for writing",
818 git_path("MERGE_MSG"));
819 fprintf(fp, "\nConflicts:\n");
820 for (pos = 0; pos < active_nr; pos++) {
821 struct cache_entry *ce = active_cache[pos];
822
823 if (ce_stage(ce)) {
824 fprintf(fp, "\t%s\n", ce->name);
825 while (pos + 1 < active_nr &&
826 !strcmp(ce->name,
827 active_cache[pos + 1]->name))
828 pos++;
829 }
830 }
831 fclose(fp);
832 rerere(allow_rerere_auto);
833 printf("Automatic merge failed; "
834 "fix conflicts and then commit the result.\n");
835 return 1;
836 }
837
838 static struct commit *is_old_style_invocation(int argc, const char **argv)
839 {
840 struct commit *second_token = NULL;
841 if (argc > 2) {
842 unsigned char second_sha1[20];
843
844 if (get_sha1(argv[1], second_sha1))
845 return NULL;
846 second_token = lookup_commit_reference_gently(second_sha1, 0);
847 if (!second_token)
848 die("'%s' is not a commit", argv[1]);
849 if (hashcmp(second_token->object.sha1, head))
850 return NULL;
851 }
852 return second_token;
853 }
854
855 static int evaluate_result(void)
856 {
857 int cnt = 0;
858 struct rev_info rev;
859
860 /* Check how many files differ. */
861 init_revisions(&rev, "");
862 setup_revisions(0, NULL, &rev, NULL);
863 rev.diffopt.output_format |=
864 DIFF_FORMAT_CALLBACK;
865 rev.diffopt.format_callback = count_diff_files;
866 rev.diffopt.format_callback_data = &cnt;
867 run_diff_files(&rev, 0);
868
869 /*
870 * Check how many unmerged entries are
871 * there.
872 */
873 cnt += count_unmerged_entries();
874
875 return cnt;
876 }
877
878 int cmd_merge(int argc, const char **argv, const char *prefix)
879 {
880 unsigned char result_tree[20];
881 struct strbuf buf = STRBUF_INIT;
882 const char *head_arg;
883 int flag, head_invalid = 0, i;
884 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
885 struct commit_list *common = NULL;
886 const char *best_strategy = NULL, *wt_strategy = NULL;
887 struct commit_list **remotes = &remoteheads;
888
889 if (read_cache_unmerged()) {
890 die_resolve_conflict("merge");
891 }
892 if (file_exists(git_path("MERGE_HEAD"))) {
893 /*
894 * There is no unmerged entry, don't advise 'git
895 * add/rm <file>', just 'git commit'.
896 */
897 if (advice_resolve_conflict)
898 die("You have not concluded your merge (MERGE_HEAD exists).\n"
899 "Please, commit your changes before you can merge.");
900 else
901 die("You have not concluded your merge (MERGE_HEAD exists).");
902 }
903
904 resolve_undo_clear();
905 /*
906 * Check if we are _not_ on a detached HEAD, i.e. if there is a
907 * current branch.
908 */
909 branch = resolve_ref("HEAD", head, 0, &flag);
910 if (branch && !prefixcmp(branch, "refs/heads/"))
911 branch += 11;
912 if (is_null_sha1(head))
913 head_invalid = 1;
914
915 git_config(git_merge_config, NULL);
916
917 /* for color.ui */
918 if (diff_use_color_default == -1)
919 diff_use_color_default = git_use_color_default;
920
921 argc = parse_options(argc, argv, prefix, builtin_merge_options,
922 builtin_merge_usage, 0);
923 if (verbosity < 0)
924 show_diffstat = 0;
925
926 if (squash) {
927 if (!allow_fast_forward)
928 die("You cannot combine --squash with --no-ff.");
929 option_commit = 0;
930 }
931
932 if (!allow_fast_forward && fast_forward_only)
933 die("You cannot combine --no-ff with --ff-only.");
934
935 if (!argc)
936 usage_with_options(builtin_merge_usage,
937 builtin_merge_options);
938
939 /*
940 * This could be traditional "merge <msg> HEAD <commit>..." and
941 * the way we can tell it is to see if the second token is HEAD,
942 * but some people might have misused the interface and used a
943 * committish that is the same as HEAD there instead.
944 * Traditional format never would have "-m" so it is an
945 * additional safety measure to check for it.
946 */
947
948 if (!have_message && is_old_style_invocation(argc, argv)) {
949 strbuf_addstr(&merge_msg, argv[0]);
950 head_arg = argv[1];
951 argv += 2;
952 argc -= 2;
953 } else if (head_invalid) {
954 struct object *remote_head;
955 /*
956 * If the merged head is a valid one there is no reason
957 * to forbid "git merge" into a branch yet to be born.
958 * We do the same for "git pull".
959 */
960 if (argc != 1)
961 die("Can merge only exactly one commit into "
962 "empty head");
963 if (squash)
964 die("Squash commit into empty head not supported yet");
965 if (!allow_fast_forward)
966 die("Non-fast-forward commit does not make sense into "
967 "an empty head");
968 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
969 if (!remote_head)
970 die("%s - not something we can merge", argv[0]);
971 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
972 DIE_ON_ERR);
973 reset_hard(remote_head->sha1, 0);
974 return 0;
975 } else {
976 struct strbuf msg = STRBUF_INIT;
977
978 /* We are invoked directly as the first-class UI. */
979 head_arg = "HEAD";
980
981 /*
982 * All the rest are the commits being merged;
983 * prepare the standard merge summary message to
984 * be appended to the given message. If remote
985 * is invalid we will die later in the common
986 * codepath so we discard the error in this
987 * loop.
988 */
989 if (!have_message) {
990 for (i = 0; i < argc; i++)
991 merge_name(argv[i], &msg);
992 fmt_merge_msg(option_log, &msg, &merge_msg);
993 if (merge_msg.len)
994 strbuf_setlen(&merge_msg, merge_msg.len-1);
995 }
996 }
997
998 if (head_invalid || !argc)
999 usage_with_options(builtin_merge_usage,
1000 builtin_merge_options);
1001
1002 strbuf_addstr(&buf, "merge");
1003 for (i = 0; i < argc; i++)
1004 strbuf_addf(&buf, " %s", argv[i]);
1005 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1006 strbuf_reset(&buf);
1007
1008 for (i = 0; i < argc; i++) {
1009 struct object *o;
1010 struct commit *commit;
1011
1012 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1013 if (!o)
1014 die("%s - not something we can merge", argv[i]);
1015 commit = lookup_commit(o->sha1);
1016 commit->util = (void *)argv[i];
1017 remotes = &commit_list_insert(commit, remotes)->next;
1018
1019 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1020 setenv(buf.buf, argv[i], 1);
1021 strbuf_reset(&buf);
1022 }
1023
1024 if (!use_strategies) {
1025 if (!remoteheads->next)
1026 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1027 else
1028 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1029 }
1030
1031 for (i = 0; i < use_strategies_nr; i++) {
1032 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1033 allow_fast_forward = 0;
1034 if (use_strategies[i]->attr & NO_TRIVIAL)
1035 allow_trivial = 0;
1036 }
1037
1038 if (!remoteheads->next)
1039 common = get_merge_bases(lookup_commit(head),
1040 remoteheads->item, 1);
1041 else {
1042 struct commit_list *list = remoteheads;
1043 commit_list_insert(lookup_commit(head), &list);
1044 common = get_octopus_merge_bases(list);
1045 free(list);
1046 }
1047
1048 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1049 DIE_ON_ERR);
1050
1051 if (!common)
1052 ; /* No common ancestors found. We need a real merge. */
1053 else if (!remoteheads->next && !common->next &&
1054 common->item == remoteheads->item) {
1055 /*
1056 * If head can reach all the merge then we are up to date.
1057 * but first the most common case of merging one remote.
1058 */
1059 finish_up_to_date("Already up-to-date.");
1060 return 0;
1061 } else if (allow_fast_forward && !remoteheads->next &&
1062 !common->next &&
1063 !hashcmp(common->item->object.sha1, head)) {
1064 /* Again the most common case of merging one remote. */
1065 struct strbuf msg = STRBUF_INIT;
1066 struct object *o;
1067 char hex[41];
1068
1069 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1070
1071 if (verbosity >= 0)
1072 printf("Updating %s..%s\n",
1073 hex,
1074 find_unique_abbrev(remoteheads->item->object.sha1,
1075 DEFAULT_ABBREV));
1076 strbuf_addstr(&msg, "Fast-forward");
1077 if (have_message)
1078 strbuf_addstr(&msg,
1079 " (no commit created; -m option ignored)");
1080 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1081 0, NULL, OBJ_COMMIT);
1082 if (!o)
1083 return 1;
1084
1085 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1086 return 1;
1087
1088 finish(o->sha1, msg.buf);
1089 drop_save();
1090 return 0;
1091 } else if (!remoteheads->next && common->next)
1092 ;
1093 /*
1094 * We are not doing octopus and not fast-forward. Need
1095 * a real merge.
1096 */
1097 else if (!remoteheads->next && !common->next && option_commit) {
1098 /*
1099 * We are not doing octopus, not fast-forward, and have
1100 * only one common.
1101 */
1102 refresh_cache(REFRESH_QUIET);
1103 if (allow_trivial && !fast_forward_only) {
1104 /* See if it is really trivial. */
1105 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1106 printf("Trying really trivial in-index merge...\n");
1107 if (!read_tree_trivial(common->item->object.sha1,
1108 head, remoteheads->item->object.sha1))
1109 return merge_trivial();
1110 printf("Nope.\n");
1111 }
1112 } else {
1113 /*
1114 * An octopus. If we can reach all the remote we are up
1115 * to date.
1116 */
1117 int up_to_date = 1;
1118 struct commit_list *j;
1119
1120 for (j = remoteheads; j; j = j->next) {
1121 struct commit_list *common_one;
1122
1123 /*
1124 * Here we *have* to calculate the individual
1125 * merge_bases again, otherwise "git merge HEAD^
1126 * HEAD^^" would be missed.
1127 */
1128 common_one = get_merge_bases(lookup_commit(head),
1129 j->item, 1);
1130 if (hashcmp(common_one->item->object.sha1,
1131 j->item->object.sha1)) {
1132 up_to_date = 0;
1133 break;
1134 }
1135 }
1136 if (up_to_date) {
1137 finish_up_to_date("Already up-to-date. Yeeah!");
1138 return 0;
1139 }
1140 }
1141
1142 if (fast_forward_only)
1143 die("Not possible to fast-forward, aborting.");
1144
1145 /* We are going to make a new commit. */
1146 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1147
1148 /*
1149 * At this point, we need a real merge. No matter what strategy
1150 * we use, it would operate on the index, possibly affecting the
1151 * working tree, and when resolved cleanly, have the desired
1152 * tree in the index -- this means that the index must be in
1153 * sync with the head commit. The strategies are responsible
1154 * to ensure this.
1155 */
1156 if (use_strategies_nr != 1) {
1157 /*
1158 * Stash away the local changes so that we can try more
1159 * than one.
1160 */
1161 save_state();
1162 } else {
1163 memcpy(stash, null_sha1, 20);
1164 }
1165
1166 for (i = 0; i < use_strategies_nr; i++) {
1167 int ret;
1168 if (i) {
1169 printf("Rewinding the tree to pristine...\n");
1170 restore_state();
1171 }
1172 if (use_strategies_nr != 1)
1173 printf("Trying merge strategy %s...\n",
1174 use_strategies[i]->name);
1175 /*
1176 * Remember which strategy left the state in the working
1177 * tree.
1178 */
1179 wt_strategy = use_strategies[i]->name;
1180
1181 ret = try_merge_strategy(use_strategies[i]->name,
1182 common, head_arg);
1183 if (!option_commit && !ret) {
1184 merge_was_ok = 1;
1185 /*
1186 * This is necessary here just to avoid writing
1187 * the tree, but later we will *not* exit with
1188 * status code 1 because merge_was_ok is set.
1189 */
1190 ret = 1;
1191 }
1192
1193 if (ret) {
1194 /*
1195 * The backend exits with 1 when conflicts are
1196 * left to be resolved, with 2 when it does not
1197 * handle the given merge at all.
1198 */
1199 if (ret == 1) {
1200 int cnt = evaluate_result();
1201
1202 if (best_cnt <= 0 || cnt <= best_cnt) {
1203 best_strategy = use_strategies[i]->name;
1204 best_cnt = cnt;
1205 }
1206 }
1207 if (merge_was_ok)
1208 break;
1209 else
1210 continue;
1211 }
1212
1213 /* Automerge succeeded. */
1214 write_tree_trivial(result_tree);
1215 automerge_was_ok = 1;
1216 break;
1217 }
1218
1219 /*
1220 * If we have a resulting tree, that means the strategy module
1221 * auto resolved the merge cleanly.
1222 */
1223 if (automerge_was_ok)
1224 return finish_automerge(common, result_tree, wt_strategy);
1225
1226 /*
1227 * Pick the result from the best strategy and have the user fix
1228 * it up.
1229 */
1230 if (!best_strategy) {
1231 restore_state();
1232 if (use_strategies_nr > 1)
1233 fprintf(stderr,
1234 "No merge strategy handled the merge.\n");
1235 else
1236 fprintf(stderr, "Merge with strategy %s failed.\n",
1237 use_strategies[0]->name);
1238 return 2;
1239 } else if (best_strategy == wt_strategy)
1240 ; /* We already have its result in the working tree. */
1241 else {
1242 printf("Rewinding the tree to pristine...\n");
1243 restore_state();
1244 printf("Using the %s to prepare resolving by hand.\n",
1245 best_strategy);
1246 try_merge_strategy(best_strategy, common, head_arg);
1247 }
1248
1249 if (squash)
1250 finish(NULL, NULL);
1251 else {
1252 int fd;
1253 struct commit_list *j;
1254
1255 for (j = remoteheads; j; j = j->next)
1256 strbuf_addf(&buf, "%s\n",
1257 sha1_to_hex(j->item->object.sha1));
1258 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1259 if (fd < 0)
1260 die_errno("Could not open '%s' for writing",
1261 git_path("MERGE_HEAD"));
1262 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1263 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1264 close(fd);
1265 strbuf_addch(&merge_msg, '\n');
1266 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1267 if (fd < 0)
1268 die_errno("Could not open '%s' for writing",
1269 git_path("MERGE_MSG"));
1270 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1271 merge_msg.len)
1272 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1273 close(fd);
1274 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1275 if (fd < 0)
1276 die_errno("Could not open '%s' for writing",
1277 git_path("MERGE_MODE"));
1278 strbuf_reset(&buf);
1279 if (!allow_fast_forward)
1280 strbuf_addf(&buf, "no-ff");
1281 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1282 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1283 close(fd);
1284 }
1285
1286 if (merge_was_ok) {
1287 fprintf(stderr, "Automatic merge went well; "
1288 "stopped before committing as requested\n");
1289 return 0;
1290 } else
1291 return suggest_conflicts();
1292 }