merge: Make '--log' an integer option for number of shortlog entries
[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, shortlog_len, 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 { OPTION_INTEGER, 0, "log", &shortlog_len, "n",
179 "add (at most <n>) entries from shortlog to merge commit message",
180 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
181 OPT_BOOLEAN(0, "squash", &squash,
182 "create a single commit instead of doing a merge"),
183 OPT_BOOLEAN(0, "commit", &option_commit,
184 "perform a commit if the merge succeeds (default)"),
185 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
186 "allow fast-forward (default)"),
187 OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
188 "abort if fast-forward is not possible"),
189 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
190 OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
191 "merge strategy to use", option_parse_strategy),
192 OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
193 "option for selected merge strategy", option_parse_x),
194 OPT_CALLBACK('m', "message", &merge_msg, "message",
195 "message to be used for the merge commit (if any)",
196 option_parse_message),
197 OPT__VERBOSITY(&verbosity),
198 OPT_END()
199 };
200
201 /* Cleans up metadata that is uninteresting after a succeeded merge. */
202 static void drop_save(void)
203 {
204 unlink(git_path("MERGE_HEAD"));
205 unlink(git_path("MERGE_MSG"));
206 unlink(git_path("MERGE_MODE"));
207 }
208
209 static void save_state(void)
210 {
211 int len;
212 struct child_process cp;
213 struct strbuf buffer = STRBUF_INIT;
214 const char *argv[] = {"stash", "create", NULL};
215
216 memset(&cp, 0, sizeof(cp));
217 cp.argv = argv;
218 cp.out = -1;
219 cp.git_cmd = 1;
220
221 if (start_command(&cp))
222 die("could not run stash.");
223 len = strbuf_read(&buffer, cp.out, 1024);
224 close(cp.out);
225
226 if (finish_command(&cp) || len < 0)
227 die("stash failed");
228 else if (!len)
229 return;
230 strbuf_setlen(&buffer, buffer.len-1);
231 if (get_sha1(buffer.buf, stash))
232 die("not a valid object: %s", buffer.buf);
233 }
234
235 static void reset_hard(unsigned const char *sha1, int verbose)
236 {
237 int i = 0;
238 const char *args[6];
239
240 args[i++] = "read-tree";
241 if (verbose)
242 args[i++] = "-v";
243 args[i++] = "--reset";
244 args[i++] = "-u";
245 args[i++] = sha1_to_hex(sha1);
246 args[i] = NULL;
247
248 if (run_command_v_opt(args, RUN_GIT_CMD))
249 die("read-tree failed");
250 }
251
252 static void restore_state(void)
253 {
254 struct strbuf sb = STRBUF_INIT;
255 const char *args[] = { "stash", "apply", NULL, NULL };
256
257 if (is_null_sha1(stash))
258 return;
259
260 reset_hard(head, 1);
261
262 args[2] = sha1_to_hex(stash);
263
264 /*
265 * It is OK to ignore error here, for example when there was
266 * nothing to restore.
267 */
268 run_command_v_opt(args, RUN_GIT_CMD);
269
270 strbuf_release(&sb);
271 refresh_cache(REFRESH_QUIET);
272 }
273
274 /* This is called when no merge was necessary. */
275 static void finish_up_to_date(const char *msg)
276 {
277 if (verbosity >= 0)
278 printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
279 drop_save();
280 }
281
282 static void squash_message(void)
283 {
284 struct rev_info rev;
285 struct commit *commit;
286 struct strbuf out = STRBUF_INIT;
287 struct commit_list *j;
288 int fd;
289 struct pretty_print_context ctx = {0};
290
291 printf("Squash commit -- not updating HEAD\n");
292 fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
293 if (fd < 0)
294 die_errno("Could not write to '%s'", git_path("SQUASH_MSG"));
295
296 init_revisions(&rev, NULL);
297 rev.ignore_merges = 1;
298 rev.commit_format = CMIT_FMT_MEDIUM;
299
300 commit = lookup_commit(head);
301 commit->object.flags |= UNINTERESTING;
302 add_pending_object(&rev, &commit->object, NULL);
303
304 for (j = remoteheads; j; j = j->next)
305 add_pending_object(&rev, &j->item->object, NULL);
306
307 setup_revisions(0, NULL, &rev, NULL);
308 if (prepare_revision_walk(&rev))
309 die("revision walk setup failed");
310
311 ctx.abbrev = rev.abbrev;
312 ctx.date_mode = rev.date_mode;
313
314 strbuf_addstr(&out, "Squashed commit of the following:\n");
315 while ((commit = get_revision(&rev)) != NULL) {
316 strbuf_addch(&out, '\n');
317 strbuf_addf(&out, "commit %s\n",
318 sha1_to_hex(commit->object.sha1));
319 pretty_print_commit(rev.commit_format, commit, &out, &ctx);
320 }
321 if (write(fd, out.buf, out.len) < 0)
322 die_errno("Writing SQUASH_MSG");
323 if (close(fd))
324 die_errno("Finishing SQUASH_MSG");
325 strbuf_release(&out);
326 }
327
328 static void finish(const unsigned char *new_head, const char *msg)
329 {
330 struct strbuf reflog_message = STRBUF_INIT;
331
332 if (!msg)
333 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
334 else {
335 if (verbosity >= 0)
336 printf("%s\n", msg);
337 strbuf_addf(&reflog_message, "%s: %s",
338 getenv("GIT_REFLOG_ACTION"), msg);
339 }
340 if (squash) {
341 squash_message();
342 } else {
343 if (verbosity >= 0 && !merge_msg.len)
344 printf("No merge message -- not updating HEAD\n");
345 else {
346 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
347 update_ref(reflog_message.buf, "HEAD",
348 new_head, head, 0,
349 DIE_ON_ERR);
350 /*
351 * We ignore errors in 'gc --auto', since the
352 * user should see them.
353 */
354 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
355 }
356 }
357 if (new_head && show_diffstat) {
358 struct diff_options opts;
359 diff_setup(&opts);
360 opts.output_format |=
361 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
362 opts.detect_rename = DIFF_DETECT_RENAME;
363 if (diff_use_color_default > 0)
364 DIFF_OPT_SET(&opts, COLOR_DIFF);
365 if (diff_setup_done(&opts) < 0)
366 die("diff_setup_done failed");
367 diff_tree_sha1(head, new_head, "", &opts);
368 diffcore_std(&opts);
369 diff_flush(&opts);
370 }
371
372 /* Run a post-merge hook */
373 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
374
375 strbuf_release(&reflog_message);
376 }
377
378 /* Get the name for the merge commit's message. */
379 static void merge_name(const char *remote, struct strbuf *msg)
380 {
381 struct object *remote_head;
382 unsigned char branch_head[20], buf_sha[20];
383 struct strbuf buf = STRBUF_INIT;
384 struct strbuf bname = STRBUF_INIT;
385 const char *ptr;
386 char *found_ref;
387 int len, early;
388
389 strbuf_branchname(&bname, remote);
390 remote = bname.buf;
391
392 memset(branch_head, 0, sizeof(branch_head));
393 remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
394 if (!remote_head)
395 die("'%s' does not point to a commit", remote);
396
397 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
398 if (!prefixcmp(found_ref, "refs/heads/")) {
399 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
400 sha1_to_hex(branch_head), remote);
401 goto cleanup;
402 }
403 if (!prefixcmp(found_ref, "refs/remotes/")) {
404 strbuf_addf(msg, "%s\t\tremote branch '%s' of .\n",
405 sha1_to_hex(branch_head), remote);
406 goto cleanup;
407 }
408 }
409
410 /* See if remote matches <name>^^^.. or <name>~<number> */
411 for (len = 0, ptr = remote + strlen(remote);
412 remote < ptr && ptr[-1] == '^';
413 ptr--)
414 len++;
415 if (len)
416 early = 1;
417 else {
418 early = 0;
419 ptr = strrchr(remote, '~');
420 if (ptr) {
421 int seen_nonzero = 0;
422
423 len++; /* count ~ */
424 while (*++ptr && isdigit(*ptr)) {
425 seen_nonzero |= (*ptr != '0');
426 len++;
427 }
428 if (*ptr)
429 len = 0; /* not ...~<number> */
430 else if (seen_nonzero)
431 early = 1;
432 else if (len == 1)
433 early = 1; /* "name~" is "name~1"! */
434 }
435 }
436 if (len) {
437 struct strbuf truname = STRBUF_INIT;
438 strbuf_addstr(&truname, "refs/heads/");
439 strbuf_addstr(&truname, remote);
440 strbuf_setlen(&truname, truname.len - len);
441 if (resolve_ref(truname.buf, buf_sha, 1, NULL)) {
442 strbuf_addf(msg,
443 "%s\t\tbranch '%s'%s of .\n",
444 sha1_to_hex(remote_head->sha1),
445 truname.buf + 11,
446 (early ? " (early part)" : ""));
447 strbuf_release(&truname);
448 goto cleanup;
449 }
450 }
451
452 if (!strcmp(remote, "FETCH_HEAD") &&
453 !access(git_path("FETCH_HEAD"), R_OK)) {
454 FILE *fp;
455 struct strbuf line = STRBUF_INIT;
456 char *ptr;
457
458 fp = fopen(git_path("FETCH_HEAD"), "r");
459 if (!fp)
460 die_errno("could not open '%s' for reading",
461 git_path("FETCH_HEAD"));
462 strbuf_getline(&line, fp, '\n');
463 fclose(fp);
464 ptr = strstr(line.buf, "\tnot-for-merge\t");
465 if (ptr)
466 strbuf_remove(&line, ptr-line.buf+1, 13);
467 strbuf_addbuf(msg, &line);
468 strbuf_release(&line);
469 goto cleanup;
470 }
471 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
472 sha1_to_hex(remote_head->sha1), remote);
473 cleanup:
474 strbuf_release(&buf);
475 strbuf_release(&bname);
476 }
477
478 static int git_merge_config(const char *k, const char *v, void *cb)
479 {
480 if (branch && !prefixcmp(k, "branch.") &&
481 !prefixcmp(k + 7, branch) &&
482 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
483 const char **argv;
484 int argc;
485 char *buf;
486
487 buf = xstrdup(v);
488 argc = split_cmdline(buf, &argv);
489 if (argc < 0)
490 die("Bad branch.%s.mergeoptions string", branch);
491 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
492 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
493 argc++;
494 parse_options(argc, argv, NULL, builtin_merge_options,
495 builtin_merge_usage, 0);
496 free(buf);
497 }
498
499 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
500 show_diffstat = git_config_bool(k, v);
501 else if (!strcmp(k, "pull.twohead"))
502 return git_config_string(&pull_twohead, k, v);
503 else if (!strcmp(k, "pull.octopus"))
504 return git_config_string(&pull_octopus, k, v);
505 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary")) {
506 shortlog_len = git_config_bool(k, v) ? DEFAULT_MERGE_LOG_LEN : 0;
507 return 0;
508 }
509 return git_diff_ui_config(k, v, cb);
510 }
511
512 static int read_tree_trivial(unsigned char *common, unsigned char *head,
513 unsigned char *one)
514 {
515 int i, nr_trees = 0;
516 struct tree *trees[MAX_UNPACK_TREES];
517 struct tree_desc t[MAX_UNPACK_TREES];
518 struct unpack_trees_options opts;
519
520 memset(&opts, 0, sizeof(opts));
521 opts.head_idx = 2;
522 opts.src_index = &the_index;
523 opts.dst_index = &the_index;
524 opts.update = 1;
525 opts.verbose_update = 1;
526 opts.trivial_merges_only = 1;
527 opts.merge = 1;
528 trees[nr_trees] = parse_tree_indirect(common);
529 if (!trees[nr_trees++])
530 return -1;
531 trees[nr_trees] = parse_tree_indirect(head);
532 if (!trees[nr_trees++])
533 return -1;
534 trees[nr_trees] = parse_tree_indirect(one);
535 if (!trees[nr_trees++])
536 return -1;
537 opts.fn = threeway_merge;
538 cache_tree_free(&active_cache_tree);
539 for (i = 0; i < nr_trees; i++) {
540 parse_tree(trees[i]);
541 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
542 }
543 if (unpack_trees(nr_trees, t, &opts))
544 return -1;
545 return 0;
546 }
547
548 static void write_tree_trivial(unsigned char *sha1)
549 {
550 if (write_cache_as_tree(sha1, 0, NULL))
551 die("git write-tree failed to write a tree");
552 }
553
554 int try_merge_command(const char *strategy, struct commit_list *common,
555 const char *head_arg, struct commit_list *remotes)
556 {
557 const char **args;
558 int i = 0, x = 0, ret;
559 struct commit_list *j;
560 struct strbuf buf = STRBUF_INIT;
561
562 args = xmalloc((4 + xopts_nr + commit_list_count(common) +
563 commit_list_count(remotes)) * sizeof(char *));
564 strbuf_addf(&buf, "merge-%s", strategy);
565 args[i++] = buf.buf;
566 for (x = 0; x < xopts_nr; x++) {
567 char *s = xmalloc(strlen(xopts[x])+2+1);
568 strcpy(s, "--");
569 strcpy(s+2, xopts[x]);
570 args[i++] = s;
571 }
572 for (j = common; j; j = j->next)
573 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
574 args[i++] = "--";
575 args[i++] = head_arg;
576 for (j = remotes; j; j = j->next)
577 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
578 args[i] = NULL;
579 ret = run_command_v_opt(args, RUN_GIT_CMD);
580 strbuf_release(&buf);
581 i = 1;
582 for (x = 0; x < xopts_nr; x++)
583 free((void *)args[i++]);
584 for (j = common; j; j = j->next)
585 free((void *)args[i++]);
586 i += 2;
587 for (j = remotes; j; j = j->next)
588 free((void *)args[i++]);
589 free(args);
590 discard_cache();
591 if (read_cache() < 0)
592 die("failed to read the cache");
593 resolve_undo_clear();
594
595 return ret;
596 }
597
598 static int try_merge_strategy(const char *strategy, struct commit_list *common,
599 const char *head_arg)
600 {
601 int index_fd;
602 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
603
604 index_fd = hold_locked_index(lock, 1);
605 refresh_cache(REFRESH_QUIET);
606 if (active_cache_changed &&
607 (write_cache(index_fd, active_cache, active_nr) ||
608 commit_locked_index(lock)))
609 return error("Unable to write index.");
610 rollback_lock_file(lock);
611
612 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
613 int clean, x;
614 struct commit *result;
615 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
616 int index_fd;
617 struct commit_list *reversed = NULL;
618 struct merge_options o;
619 struct commit_list *j;
620
621 if (remoteheads->next) {
622 error("Not handling anything other than two heads merge.");
623 return 2;
624 }
625
626 init_merge_options(&o);
627 if (!strcmp(strategy, "subtree"))
628 o.subtree_shift = "";
629
630 for (x = 0; x < xopts_nr; x++) {
631 if (!strcmp(xopts[x], "ours"))
632 o.recursive_variant = MERGE_RECURSIVE_OURS;
633 else if (!strcmp(xopts[x], "theirs"))
634 o.recursive_variant = MERGE_RECURSIVE_THEIRS;
635 else if (!strcmp(xopts[x], "subtree"))
636 o.subtree_shift = "";
637 else if (!prefixcmp(xopts[x], "subtree="))
638 o.subtree_shift = xopts[x]+8;
639 else
640 die("Unknown option for merge-recursive: -X%s", xopts[x]);
641 }
642
643 o.branch1 = head_arg;
644 o.branch2 = remoteheads->item->util;
645
646 for (j = common; j; j = j->next)
647 commit_list_insert(j->item, &reversed);
648
649 index_fd = hold_locked_index(lock, 1);
650 clean = merge_recursive(&o, lookup_commit(head),
651 remoteheads->item, reversed, &result);
652 if (active_cache_changed &&
653 (write_cache(index_fd, active_cache, active_nr) ||
654 commit_locked_index(lock)))
655 die ("unable to write %s", get_index_file());
656 rollback_lock_file(lock);
657 return clean ? 0 : 1;
658 } else {
659 return try_merge_command(strategy, common, head_arg, remoteheads);
660 }
661 }
662
663 static void count_diff_files(struct diff_queue_struct *q,
664 struct diff_options *opt, void *data)
665 {
666 int *count = data;
667
668 (*count) += q->nr;
669 }
670
671 static int count_unmerged_entries(void)
672 {
673 int i, ret = 0;
674
675 for (i = 0; i < active_nr; i++)
676 if (ce_stage(active_cache[i]))
677 ret++;
678
679 return ret;
680 }
681
682 int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
683 {
684 struct tree *trees[MAX_UNPACK_TREES];
685 struct unpack_trees_options opts;
686 struct tree_desc t[MAX_UNPACK_TREES];
687 int i, fd, nr_trees = 0;
688 struct dir_struct dir;
689 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
690
691 refresh_cache(REFRESH_QUIET);
692
693 fd = hold_locked_index(lock_file, 1);
694
695 memset(&trees, 0, sizeof(trees));
696 memset(&opts, 0, sizeof(opts));
697 memset(&t, 0, sizeof(t));
698 memset(&dir, 0, sizeof(dir));
699 dir.flags |= DIR_SHOW_IGNORED;
700 dir.exclude_per_dir = ".gitignore";
701 opts.dir = &dir;
702
703 opts.head_idx = 1;
704 opts.src_index = &the_index;
705 opts.dst_index = &the_index;
706 opts.update = 1;
707 opts.verbose_update = 1;
708 opts.merge = 1;
709 opts.fn = twoway_merge;
710 opts.msgs = get_porcelain_error_msgs();
711
712 trees[nr_trees] = parse_tree_indirect(head);
713 if (!trees[nr_trees++])
714 return -1;
715 trees[nr_trees] = parse_tree_indirect(remote);
716 if (!trees[nr_trees++])
717 return -1;
718 for (i = 0; i < nr_trees; i++) {
719 parse_tree(trees[i]);
720 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
721 }
722 if (unpack_trees(nr_trees, t, &opts))
723 return -1;
724 if (write_cache(fd, active_cache, active_nr) ||
725 commit_locked_index(lock_file))
726 die("unable to write new index file");
727 return 0;
728 }
729
730 static void split_merge_strategies(const char *string, struct strategy **list,
731 int *nr, int *alloc)
732 {
733 char *p, *q, *buf;
734
735 if (!string)
736 return;
737
738 buf = xstrdup(string);
739 q = buf;
740 for (;;) {
741 p = strchr(q, ' ');
742 if (!p) {
743 ALLOC_GROW(*list, *nr + 1, *alloc);
744 (*list)[(*nr)++].name = xstrdup(q);
745 free(buf);
746 return;
747 } else {
748 *p = '\0';
749 ALLOC_GROW(*list, *nr + 1, *alloc);
750 (*list)[(*nr)++].name = xstrdup(q);
751 q = ++p;
752 }
753 }
754 }
755
756 static void add_strategies(const char *string, unsigned attr)
757 {
758 struct strategy *list = NULL;
759 int list_alloc = 0, list_nr = 0, i;
760
761 memset(&list, 0, sizeof(list));
762 split_merge_strategies(string, &list, &list_nr, &list_alloc);
763 if (list) {
764 for (i = 0; i < list_nr; i++)
765 append_strategy(get_strategy(list[i].name));
766 return;
767 }
768 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
769 if (all_strategy[i].attr & attr)
770 append_strategy(&all_strategy[i]);
771
772 }
773
774 static int merge_trivial(void)
775 {
776 unsigned char result_tree[20], result_commit[20];
777 struct commit_list *parent = xmalloc(sizeof(*parent));
778
779 write_tree_trivial(result_tree);
780 printf("Wonderful.\n");
781 parent->item = lookup_commit(head);
782 parent->next = xmalloc(sizeof(*parent->next));
783 parent->next->item = remoteheads->item;
784 parent->next->next = NULL;
785 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
786 finish(result_commit, "In-index merge");
787 drop_save();
788 return 0;
789 }
790
791 static int finish_automerge(struct commit_list *common,
792 unsigned char *result_tree,
793 const char *wt_strategy)
794 {
795 struct commit_list *parents = NULL, *j;
796 struct strbuf buf = STRBUF_INIT;
797 unsigned char result_commit[20];
798
799 free_commit_list(common);
800 if (allow_fast_forward) {
801 parents = remoteheads;
802 commit_list_insert(lookup_commit(head), &parents);
803 parents = reduce_heads(parents);
804 } else {
805 struct commit_list **pptr = &parents;
806
807 pptr = &commit_list_insert(lookup_commit(head),
808 pptr)->next;
809 for (j = remoteheads; j; j = j->next)
810 pptr = &commit_list_insert(j->item, pptr)->next;
811 }
812 free_commit_list(remoteheads);
813 strbuf_addch(&merge_msg, '\n');
814 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
815 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
816 finish(result_commit, buf.buf);
817 strbuf_release(&buf);
818 drop_save();
819 return 0;
820 }
821
822 static int suggest_conflicts(void)
823 {
824 FILE *fp;
825 int pos;
826
827 fp = fopen(git_path("MERGE_MSG"), "a");
828 if (!fp)
829 die_errno("Could not open '%s' for writing",
830 git_path("MERGE_MSG"));
831 fprintf(fp, "\nConflicts:\n");
832 for (pos = 0; pos < active_nr; pos++) {
833 struct cache_entry *ce = active_cache[pos];
834
835 if (ce_stage(ce)) {
836 fprintf(fp, "\t%s\n", ce->name);
837 while (pos + 1 < active_nr &&
838 !strcmp(ce->name,
839 active_cache[pos + 1]->name))
840 pos++;
841 }
842 }
843 fclose(fp);
844 rerere(allow_rerere_auto);
845 printf("Automatic merge failed; "
846 "fix conflicts and then commit the result.\n");
847 return 1;
848 }
849
850 static struct commit *is_old_style_invocation(int argc, const char **argv)
851 {
852 struct commit *second_token = NULL;
853 if (argc > 2) {
854 unsigned char second_sha1[20];
855
856 if (get_sha1(argv[1], second_sha1))
857 return NULL;
858 second_token = lookup_commit_reference_gently(second_sha1, 0);
859 if (!second_token)
860 die("'%s' is not a commit", argv[1]);
861 if (hashcmp(second_token->object.sha1, head))
862 return NULL;
863 }
864 return second_token;
865 }
866
867 static int evaluate_result(void)
868 {
869 int cnt = 0;
870 struct rev_info rev;
871
872 /* Check how many files differ. */
873 init_revisions(&rev, "");
874 setup_revisions(0, NULL, &rev, NULL);
875 rev.diffopt.output_format |=
876 DIFF_FORMAT_CALLBACK;
877 rev.diffopt.format_callback = count_diff_files;
878 rev.diffopt.format_callback_data = &cnt;
879 run_diff_files(&rev, 0);
880
881 /*
882 * Check how many unmerged entries are
883 * there.
884 */
885 cnt += count_unmerged_entries();
886
887 return cnt;
888 }
889
890 int cmd_merge(int argc, const char **argv, const char *prefix)
891 {
892 unsigned char result_tree[20];
893 struct strbuf buf = STRBUF_INIT;
894 const char *head_arg;
895 int flag, head_invalid = 0, i;
896 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
897 struct commit_list *common = NULL;
898 const char *best_strategy = NULL, *wt_strategy = NULL;
899 struct commit_list **remotes = &remoteheads;
900
901 if (read_cache_unmerged()) {
902 die_resolve_conflict("merge");
903 }
904 if (file_exists(git_path("MERGE_HEAD"))) {
905 /*
906 * There is no unmerged entry, don't advise 'git
907 * add/rm <file>', just 'git commit'.
908 */
909 if (advice_resolve_conflict)
910 die("You have not concluded your merge (MERGE_HEAD exists).\n"
911 "Please, commit your changes before you can merge.");
912 else
913 die("You have not concluded your merge (MERGE_HEAD exists).");
914 }
915
916 resolve_undo_clear();
917 /*
918 * Check if we are _not_ on a detached HEAD, i.e. if there is a
919 * current branch.
920 */
921 branch = resolve_ref("HEAD", head, 0, &flag);
922 if (branch && !prefixcmp(branch, "refs/heads/"))
923 branch += 11;
924 if (is_null_sha1(head))
925 head_invalid = 1;
926
927 git_config(git_merge_config, NULL);
928
929 /* for color.ui */
930 if (diff_use_color_default == -1)
931 diff_use_color_default = git_use_color_default;
932
933 argc = parse_options(argc, argv, prefix, builtin_merge_options,
934 builtin_merge_usage, 0);
935 if (verbosity < 0)
936 show_diffstat = 0;
937
938 if (squash) {
939 if (!allow_fast_forward)
940 die("You cannot combine --squash with --no-ff.");
941 option_commit = 0;
942 }
943
944 if (!allow_fast_forward && fast_forward_only)
945 die("You cannot combine --no-ff with --ff-only.");
946
947 if (!argc)
948 usage_with_options(builtin_merge_usage,
949 builtin_merge_options);
950
951 /*
952 * This could be traditional "merge <msg> HEAD <commit>..." and
953 * the way we can tell it is to see if the second token is HEAD,
954 * but some people might have misused the interface and used a
955 * committish that is the same as HEAD there instead.
956 * Traditional format never would have "-m" so it is an
957 * additional safety measure to check for it.
958 */
959
960 if (!have_message && is_old_style_invocation(argc, argv)) {
961 strbuf_addstr(&merge_msg, argv[0]);
962 head_arg = argv[1];
963 argv += 2;
964 argc -= 2;
965 } else if (head_invalid) {
966 struct object *remote_head;
967 /*
968 * If the merged head is a valid one there is no reason
969 * to forbid "git merge" into a branch yet to be born.
970 * We do the same for "git pull".
971 */
972 if (argc != 1)
973 die("Can merge only exactly one commit into "
974 "empty head");
975 if (squash)
976 die("Squash commit into empty head not supported yet");
977 if (!allow_fast_forward)
978 die("Non-fast-forward commit does not make sense into "
979 "an empty head");
980 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
981 if (!remote_head)
982 die("%s - not something we can merge", argv[0]);
983 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
984 DIE_ON_ERR);
985 reset_hard(remote_head->sha1, 0);
986 return 0;
987 } else {
988 struct strbuf merge_names = STRBUF_INIT;
989
990 /* We are invoked directly as the first-class UI. */
991 head_arg = "HEAD";
992
993 /*
994 * All the rest are the commits being merged;
995 * prepare the standard merge summary message to
996 * be appended to the given message. If remote
997 * is invalid we will die later in the common
998 * codepath so we discard the error in this
999 * loop.
1000 */
1001 for (i = 0; i < argc; i++)
1002 merge_name(argv[i], &merge_names);
1003
1004 if (!have_message || shortlog_len) {
1005 fmt_merge_msg(&merge_names, &merge_msg, !have_message,
1006 shortlog_len);
1007 if (merge_msg.len)
1008 strbuf_setlen(&merge_msg, merge_msg.len - 1);
1009 }
1010 }
1011
1012 if (head_invalid || !argc)
1013 usage_with_options(builtin_merge_usage,
1014 builtin_merge_options);
1015
1016 strbuf_addstr(&buf, "merge");
1017 for (i = 0; i < argc; i++)
1018 strbuf_addf(&buf, " %s", argv[i]);
1019 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1020 strbuf_reset(&buf);
1021
1022 for (i = 0; i < argc; i++) {
1023 struct object *o;
1024 struct commit *commit;
1025
1026 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1027 if (!o)
1028 die("%s - not something we can merge", argv[i]);
1029 commit = lookup_commit(o->sha1);
1030 commit->util = (void *)argv[i];
1031 remotes = &commit_list_insert(commit, remotes)->next;
1032
1033 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1034 setenv(buf.buf, argv[i], 1);
1035 strbuf_reset(&buf);
1036 }
1037
1038 if (!use_strategies) {
1039 if (!remoteheads->next)
1040 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1041 else
1042 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1043 }
1044
1045 for (i = 0; i < use_strategies_nr; i++) {
1046 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1047 allow_fast_forward = 0;
1048 if (use_strategies[i]->attr & NO_TRIVIAL)
1049 allow_trivial = 0;
1050 }
1051
1052 if (!remoteheads->next)
1053 common = get_merge_bases(lookup_commit(head),
1054 remoteheads->item, 1);
1055 else {
1056 struct commit_list *list = remoteheads;
1057 commit_list_insert(lookup_commit(head), &list);
1058 common = get_octopus_merge_bases(list);
1059 free(list);
1060 }
1061
1062 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1063 DIE_ON_ERR);
1064
1065 if (!common)
1066 ; /* No common ancestors found. We need a real merge. */
1067 else if (!remoteheads->next && !common->next &&
1068 common->item == remoteheads->item) {
1069 /*
1070 * If head can reach all the merge then we are up to date.
1071 * but first the most common case of merging one remote.
1072 */
1073 finish_up_to_date("Already up-to-date.");
1074 return 0;
1075 } else if (allow_fast_forward && !remoteheads->next &&
1076 !common->next &&
1077 !hashcmp(common->item->object.sha1, head)) {
1078 /* Again the most common case of merging one remote. */
1079 struct strbuf msg = STRBUF_INIT;
1080 struct object *o;
1081 char hex[41];
1082
1083 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1084
1085 if (verbosity >= 0)
1086 printf("Updating %s..%s\n",
1087 hex,
1088 find_unique_abbrev(remoteheads->item->object.sha1,
1089 DEFAULT_ABBREV));
1090 strbuf_addstr(&msg, "Fast-forward");
1091 if (have_message)
1092 strbuf_addstr(&msg,
1093 " (no commit created; -m option ignored)");
1094 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1095 0, NULL, OBJ_COMMIT);
1096 if (!o)
1097 return 1;
1098
1099 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1100 return 1;
1101
1102 finish(o->sha1, msg.buf);
1103 drop_save();
1104 return 0;
1105 } else if (!remoteheads->next && common->next)
1106 ;
1107 /*
1108 * We are not doing octopus and not fast-forward. Need
1109 * a real merge.
1110 */
1111 else if (!remoteheads->next && !common->next && option_commit) {
1112 /*
1113 * We are not doing octopus, not fast-forward, and have
1114 * only one common.
1115 */
1116 refresh_cache(REFRESH_QUIET);
1117 if (allow_trivial && !fast_forward_only) {
1118 /* See if it is really trivial. */
1119 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1120 printf("Trying really trivial in-index merge...\n");
1121 if (!read_tree_trivial(common->item->object.sha1,
1122 head, remoteheads->item->object.sha1))
1123 return merge_trivial();
1124 printf("Nope.\n");
1125 }
1126 } else {
1127 /*
1128 * An octopus. If we can reach all the remote we are up
1129 * to date.
1130 */
1131 int up_to_date = 1;
1132 struct commit_list *j;
1133
1134 for (j = remoteheads; j; j = j->next) {
1135 struct commit_list *common_one;
1136
1137 /*
1138 * Here we *have* to calculate the individual
1139 * merge_bases again, otherwise "git merge HEAD^
1140 * HEAD^^" would be missed.
1141 */
1142 common_one = get_merge_bases(lookup_commit(head),
1143 j->item, 1);
1144 if (hashcmp(common_one->item->object.sha1,
1145 j->item->object.sha1)) {
1146 up_to_date = 0;
1147 break;
1148 }
1149 }
1150 if (up_to_date) {
1151 finish_up_to_date("Already up-to-date. Yeeah!");
1152 return 0;
1153 }
1154 }
1155
1156 if (fast_forward_only)
1157 die("Not possible to fast-forward, aborting.");
1158
1159 /* We are going to make a new commit. */
1160 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1161
1162 /*
1163 * At this point, we need a real merge. No matter what strategy
1164 * we use, it would operate on the index, possibly affecting the
1165 * working tree, and when resolved cleanly, have the desired
1166 * tree in the index -- this means that the index must be in
1167 * sync with the head commit. The strategies are responsible
1168 * to ensure this.
1169 */
1170 if (use_strategies_nr != 1) {
1171 /*
1172 * Stash away the local changes so that we can try more
1173 * than one.
1174 */
1175 save_state();
1176 } else {
1177 memcpy(stash, null_sha1, 20);
1178 }
1179
1180 for (i = 0; i < use_strategies_nr; i++) {
1181 int ret;
1182 if (i) {
1183 printf("Rewinding the tree to pristine...\n");
1184 restore_state();
1185 }
1186 if (use_strategies_nr != 1)
1187 printf("Trying merge strategy %s...\n",
1188 use_strategies[i]->name);
1189 /*
1190 * Remember which strategy left the state in the working
1191 * tree.
1192 */
1193 wt_strategy = use_strategies[i]->name;
1194
1195 ret = try_merge_strategy(use_strategies[i]->name,
1196 common, head_arg);
1197 if (!option_commit && !ret) {
1198 merge_was_ok = 1;
1199 /*
1200 * This is necessary here just to avoid writing
1201 * the tree, but later we will *not* exit with
1202 * status code 1 because merge_was_ok is set.
1203 */
1204 ret = 1;
1205 }
1206
1207 if (ret) {
1208 /*
1209 * The backend exits with 1 when conflicts are
1210 * left to be resolved, with 2 when it does not
1211 * handle the given merge at all.
1212 */
1213 if (ret == 1) {
1214 int cnt = evaluate_result();
1215
1216 if (best_cnt <= 0 || cnt <= best_cnt) {
1217 best_strategy = use_strategies[i]->name;
1218 best_cnt = cnt;
1219 }
1220 }
1221 if (merge_was_ok)
1222 break;
1223 else
1224 continue;
1225 }
1226
1227 /* Automerge succeeded. */
1228 write_tree_trivial(result_tree);
1229 automerge_was_ok = 1;
1230 break;
1231 }
1232
1233 /*
1234 * If we have a resulting tree, that means the strategy module
1235 * auto resolved the merge cleanly.
1236 */
1237 if (automerge_was_ok)
1238 return finish_automerge(common, result_tree, wt_strategy);
1239
1240 /*
1241 * Pick the result from the best strategy and have the user fix
1242 * it up.
1243 */
1244 if (!best_strategy) {
1245 restore_state();
1246 if (use_strategies_nr > 1)
1247 fprintf(stderr,
1248 "No merge strategy handled the merge.\n");
1249 else
1250 fprintf(stderr, "Merge with strategy %s failed.\n",
1251 use_strategies[0]->name);
1252 return 2;
1253 } else if (best_strategy == wt_strategy)
1254 ; /* We already have its result in the working tree. */
1255 else {
1256 printf("Rewinding the tree to pristine...\n");
1257 restore_state();
1258 printf("Using the %s to prepare resolving by hand.\n",
1259 best_strategy);
1260 try_merge_strategy(best_strategy, common, head_arg);
1261 }
1262
1263 if (squash)
1264 finish(NULL, NULL);
1265 else {
1266 int fd;
1267 struct commit_list *j;
1268
1269 for (j = remoteheads; j; j = j->next)
1270 strbuf_addf(&buf, "%s\n",
1271 sha1_to_hex(j->item->object.sha1));
1272 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1273 if (fd < 0)
1274 die_errno("Could not open '%s' for writing",
1275 git_path("MERGE_HEAD"));
1276 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1277 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1278 close(fd);
1279 strbuf_addch(&merge_msg, '\n');
1280 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1281 if (fd < 0)
1282 die_errno("Could not open '%s' for writing",
1283 git_path("MERGE_MSG"));
1284 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1285 merge_msg.len)
1286 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1287 close(fd);
1288 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1289 if (fd < 0)
1290 die_errno("Could not open '%s' for writing",
1291 git_path("MERGE_MODE"));
1292 strbuf_reset(&buf);
1293 if (!allow_fast_forward)
1294 strbuf_addf(&buf, "no-ff");
1295 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1296 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1297 close(fd);
1298 }
1299
1300 if (merge_was_ok) {
1301 fprintf(stderr, "Automatic merge went well; "
1302 "stopped before committing as requested\n");
1303 return 0;
1304 } else
1305 return suggest_conflicts();
1306 }