Merge branch 'js/maint-am-rebase-invalid-author'
[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 **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 int try_merge_command(const char *strategy, struct commit_list *common,
552 const char *head_arg, struct commit_list *remotes)
553 {
554 const char **args;
555 int i = 0, x = 0, ret;
556 struct commit_list *j;
557 struct strbuf buf = STRBUF_INIT;
558
559 args = xmalloc((4 + xopts_nr + commit_list_count(common) +
560 commit_list_count(remotes)) * sizeof(char *));
561 strbuf_addf(&buf, "merge-%s", strategy);
562 args[i++] = buf.buf;
563 for (x = 0; x < xopts_nr; x++) {
564 char *s = xmalloc(strlen(xopts[x])+2+1);
565 strcpy(s, "--");
566 strcpy(s+2, xopts[x]);
567 args[i++] = s;
568 }
569 for (j = common; j; j = j->next)
570 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
571 args[i++] = "--";
572 args[i++] = head_arg;
573 for (j = remotes; j; j = j->next)
574 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
575 args[i] = NULL;
576 ret = run_command_v_opt(args, RUN_GIT_CMD);
577 strbuf_release(&buf);
578 i = 1;
579 for (x = 0; x < xopts_nr; x++)
580 free((void *)args[i++]);
581 for (j = common; j; j = j->next)
582 free((void *)args[i++]);
583 i += 2;
584 for (j = remotes; j; j = j->next)
585 free((void *)args[i++]);
586 free(args);
587 discard_cache();
588 if (read_cache() < 0)
589 die("failed to read the cache");
590 resolve_undo_clear();
591
592 return ret;
593 }
594
595 static int try_merge_strategy(const char *strategy, struct commit_list *common,
596 const char *head_arg)
597 {
598 int index_fd;
599 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
600
601 index_fd = hold_locked_index(lock, 1);
602 refresh_cache(REFRESH_QUIET);
603 if (active_cache_changed &&
604 (write_cache(index_fd, active_cache, active_nr) ||
605 commit_locked_index(lock)))
606 return error("Unable to write index.");
607 rollback_lock_file(lock);
608
609 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
610 int clean, x;
611 struct commit *result;
612 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
613 int index_fd;
614 struct commit_list *reversed = NULL;
615 struct merge_options o;
616 struct commit_list *j;
617
618 if (remoteheads->next) {
619 error("Not handling anything other than two heads merge.");
620 return 2;
621 }
622
623 init_merge_options(&o);
624 if (!strcmp(strategy, "subtree"))
625 o.subtree_shift = "";
626
627 for (x = 0; x < xopts_nr; x++) {
628 if (!strcmp(xopts[x], "ours"))
629 o.recursive_variant = MERGE_RECURSIVE_OURS;
630 else if (!strcmp(xopts[x], "theirs"))
631 o.recursive_variant = MERGE_RECURSIVE_THEIRS;
632 else if (!strcmp(xopts[x], "subtree"))
633 o.subtree_shift = "";
634 else if (!prefixcmp(xopts[x], "subtree="))
635 o.subtree_shift = xopts[x]+8;
636 else
637 die("Unknown option for merge-recursive: -X%s", xopts[x]);
638 }
639
640 o.branch1 = head_arg;
641 o.branch2 = remoteheads->item->util;
642
643 for (j = common; j; j = j->next)
644 commit_list_insert(j->item, &reversed);
645
646 index_fd = hold_locked_index(lock, 1);
647 clean = merge_recursive(&o, lookup_commit(head),
648 remoteheads->item, reversed, &result);
649 if (active_cache_changed &&
650 (write_cache(index_fd, active_cache, active_nr) ||
651 commit_locked_index(lock)))
652 die ("unable to write %s", get_index_file());
653 rollback_lock_file(lock);
654 return clean ? 0 : 1;
655 } else {
656 return try_merge_command(strategy, common, head_arg, remoteheads);
657 }
658 }
659
660 static void count_diff_files(struct diff_queue_struct *q,
661 struct diff_options *opt, void *data)
662 {
663 int *count = data;
664
665 (*count) += q->nr;
666 }
667
668 static int count_unmerged_entries(void)
669 {
670 int i, ret = 0;
671
672 for (i = 0; i < active_nr; i++)
673 if (ce_stage(active_cache[i]))
674 ret++;
675
676 return ret;
677 }
678
679 int checkout_fast_forward(const unsigned char *head, const unsigned char *remote)
680 {
681 struct tree *trees[MAX_UNPACK_TREES];
682 struct unpack_trees_options opts;
683 struct tree_desc t[MAX_UNPACK_TREES];
684 int i, fd, nr_trees = 0;
685 struct dir_struct dir;
686 struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
687
688 refresh_cache(REFRESH_QUIET);
689
690 fd = hold_locked_index(lock_file, 1);
691
692 memset(&trees, 0, sizeof(trees));
693 memset(&opts, 0, sizeof(opts));
694 memset(&t, 0, sizeof(t));
695 memset(&dir, 0, sizeof(dir));
696 dir.flags |= DIR_SHOW_IGNORED;
697 dir.exclude_per_dir = ".gitignore";
698 opts.dir = &dir;
699
700 opts.head_idx = 1;
701 opts.src_index = &the_index;
702 opts.dst_index = &the_index;
703 opts.update = 1;
704 opts.verbose_update = 1;
705 opts.merge = 1;
706 opts.fn = twoway_merge;
707 opts.msgs = get_porcelain_error_msgs();
708
709 trees[nr_trees] = parse_tree_indirect(head);
710 if (!trees[nr_trees++])
711 return -1;
712 trees[nr_trees] = parse_tree_indirect(remote);
713 if (!trees[nr_trees++])
714 return -1;
715 for (i = 0; i < nr_trees; i++) {
716 parse_tree(trees[i]);
717 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
718 }
719 if (unpack_trees(nr_trees, t, &opts))
720 return -1;
721 if (write_cache(fd, active_cache, active_nr) ||
722 commit_locked_index(lock_file))
723 die("unable to write new index file");
724 return 0;
725 }
726
727 static void split_merge_strategies(const char *string, struct strategy **list,
728 int *nr, int *alloc)
729 {
730 char *p, *q, *buf;
731
732 if (!string)
733 return;
734
735 buf = xstrdup(string);
736 q = buf;
737 for (;;) {
738 p = strchr(q, ' ');
739 if (!p) {
740 ALLOC_GROW(*list, *nr + 1, *alloc);
741 (*list)[(*nr)++].name = xstrdup(q);
742 free(buf);
743 return;
744 } else {
745 *p = '\0';
746 ALLOC_GROW(*list, *nr + 1, *alloc);
747 (*list)[(*nr)++].name = xstrdup(q);
748 q = ++p;
749 }
750 }
751 }
752
753 static void add_strategies(const char *string, unsigned attr)
754 {
755 struct strategy *list = NULL;
756 int list_alloc = 0, list_nr = 0, i;
757
758 memset(&list, 0, sizeof(list));
759 split_merge_strategies(string, &list, &list_nr, &list_alloc);
760 if (list) {
761 for (i = 0; i < list_nr; i++)
762 append_strategy(get_strategy(list[i].name));
763 return;
764 }
765 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
766 if (all_strategy[i].attr & attr)
767 append_strategy(&all_strategy[i]);
768
769 }
770
771 static int merge_trivial(void)
772 {
773 unsigned char result_tree[20], result_commit[20];
774 struct commit_list *parent = xmalloc(sizeof(*parent));
775
776 write_tree_trivial(result_tree);
777 printf("Wonderful.\n");
778 parent->item = lookup_commit(head);
779 parent->next = xmalloc(sizeof(*parent->next));
780 parent->next->item = remoteheads->item;
781 parent->next->next = NULL;
782 commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
783 finish(result_commit, "In-index merge");
784 drop_save();
785 return 0;
786 }
787
788 static int finish_automerge(struct commit_list *common,
789 unsigned char *result_tree,
790 const char *wt_strategy)
791 {
792 struct commit_list *parents = NULL, *j;
793 struct strbuf buf = STRBUF_INIT;
794 unsigned char result_commit[20];
795
796 free_commit_list(common);
797 if (allow_fast_forward) {
798 parents = remoteheads;
799 commit_list_insert(lookup_commit(head), &parents);
800 parents = reduce_heads(parents);
801 } else {
802 struct commit_list **pptr = &parents;
803
804 pptr = &commit_list_insert(lookup_commit(head),
805 pptr)->next;
806 for (j = remoteheads; j; j = j->next)
807 pptr = &commit_list_insert(j->item, pptr)->next;
808 }
809 free_commit_list(remoteheads);
810 strbuf_addch(&merge_msg, '\n');
811 commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
812 strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
813 finish(result_commit, buf.buf);
814 strbuf_release(&buf);
815 drop_save();
816 return 0;
817 }
818
819 static int suggest_conflicts(void)
820 {
821 FILE *fp;
822 int pos;
823
824 fp = fopen(git_path("MERGE_MSG"), "a");
825 if (!fp)
826 die_errno("Could not open '%s' for writing",
827 git_path("MERGE_MSG"));
828 fprintf(fp, "\nConflicts:\n");
829 for (pos = 0; pos < active_nr; pos++) {
830 struct cache_entry *ce = active_cache[pos];
831
832 if (ce_stage(ce)) {
833 fprintf(fp, "\t%s\n", ce->name);
834 while (pos + 1 < active_nr &&
835 !strcmp(ce->name,
836 active_cache[pos + 1]->name))
837 pos++;
838 }
839 }
840 fclose(fp);
841 rerere(allow_rerere_auto);
842 printf("Automatic merge failed; "
843 "fix conflicts and then commit the result.\n");
844 return 1;
845 }
846
847 static struct commit *is_old_style_invocation(int argc, const char **argv)
848 {
849 struct commit *second_token = NULL;
850 if (argc > 2) {
851 unsigned char second_sha1[20];
852
853 if (get_sha1(argv[1], second_sha1))
854 return NULL;
855 second_token = lookup_commit_reference_gently(second_sha1, 0);
856 if (!second_token)
857 die("'%s' is not a commit", argv[1]);
858 if (hashcmp(second_token->object.sha1, head))
859 return NULL;
860 }
861 return second_token;
862 }
863
864 static int evaluate_result(void)
865 {
866 int cnt = 0;
867 struct rev_info rev;
868
869 /* Check how many files differ. */
870 init_revisions(&rev, "");
871 setup_revisions(0, NULL, &rev, NULL);
872 rev.diffopt.output_format |=
873 DIFF_FORMAT_CALLBACK;
874 rev.diffopt.format_callback = count_diff_files;
875 rev.diffopt.format_callback_data = &cnt;
876 run_diff_files(&rev, 0);
877
878 /*
879 * Check how many unmerged entries are
880 * there.
881 */
882 cnt += count_unmerged_entries();
883
884 return cnt;
885 }
886
887 int cmd_merge(int argc, const char **argv, const char *prefix)
888 {
889 unsigned char result_tree[20];
890 struct strbuf buf = STRBUF_INIT;
891 const char *head_arg;
892 int flag, head_invalid = 0, i;
893 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
894 struct commit_list *common = NULL;
895 const char *best_strategy = NULL, *wt_strategy = NULL;
896 struct commit_list **remotes = &remoteheads;
897
898 if (read_cache_unmerged()) {
899 die_resolve_conflict("merge");
900 }
901 if (file_exists(git_path("MERGE_HEAD"))) {
902 /*
903 * There is no unmerged entry, don't advise 'git
904 * add/rm <file>', just 'git commit'.
905 */
906 if (advice_resolve_conflict)
907 die("You have not concluded your merge (MERGE_HEAD exists).\n"
908 "Please, commit your changes before you can merge.");
909 else
910 die("You have not concluded your merge (MERGE_HEAD exists).");
911 }
912
913 resolve_undo_clear();
914 /*
915 * Check if we are _not_ on a detached HEAD, i.e. if there is a
916 * current branch.
917 */
918 branch = resolve_ref("HEAD", head, 0, &flag);
919 if (branch && !prefixcmp(branch, "refs/heads/"))
920 branch += 11;
921 if (is_null_sha1(head))
922 head_invalid = 1;
923
924 git_config(git_merge_config, NULL);
925
926 /* for color.ui */
927 if (diff_use_color_default == -1)
928 diff_use_color_default = git_use_color_default;
929
930 argc = parse_options(argc, argv, prefix, builtin_merge_options,
931 builtin_merge_usage, 0);
932 if (verbosity < 0)
933 show_diffstat = 0;
934
935 if (squash) {
936 if (!allow_fast_forward)
937 die("You cannot combine --squash with --no-ff.");
938 option_commit = 0;
939 }
940
941 if (!allow_fast_forward && fast_forward_only)
942 die("You cannot combine --no-ff with --ff-only.");
943
944 if (!argc)
945 usage_with_options(builtin_merge_usage,
946 builtin_merge_options);
947
948 /*
949 * This could be traditional "merge <msg> HEAD <commit>..." and
950 * the way we can tell it is to see if the second token is HEAD,
951 * but some people might have misused the interface and used a
952 * committish that is the same as HEAD there instead.
953 * Traditional format never would have "-m" so it is an
954 * additional safety measure to check for it.
955 */
956
957 if (!have_message && is_old_style_invocation(argc, argv)) {
958 strbuf_addstr(&merge_msg, argv[0]);
959 head_arg = argv[1];
960 argv += 2;
961 argc -= 2;
962 } else if (head_invalid) {
963 struct object *remote_head;
964 /*
965 * If the merged head is a valid one there is no reason
966 * to forbid "git merge" into a branch yet to be born.
967 * We do the same for "git pull".
968 */
969 if (argc != 1)
970 die("Can merge only exactly one commit into "
971 "empty head");
972 if (squash)
973 die("Squash commit into empty head not supported yet");
974 if (!allow_fast_forward)
975 die("Non-fast-forward commit does not make sense into "
976 "an empty head");
977 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
978 if (!remote_head)
979 die("%s - not something we can merge", argv[0]);
980 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
981 DIE_ON_ERR);
982 reset_hard(remote_head->sha1, 0);
983 return 0;
984 } else {
985 struct strbuf merge_names = STRBUF_INIT;
986
987 /* We are invoked directly as the first-class UI. */
988 head_arg = "HEAD";
989
990 /*
991 * All the rest are the commits being merged;
992 * prepare the standard merge summary message to
993 * be appended to the given message. If remote
994 * is invalid we will die later in the common
995 * codepath so we discard the error in this
996 * loop.
997 */
998 for (i = 0; i < argc; i++)
999 merge_name(argv[i], &merge_names);
1000
1001 if (have_message && option_log)
1002 fmt_merge_msg_shortlog(&merge_names, &merge_msg);
1003 else if (!have_message)
1004 fmt_merge_msg(option_log, &merge_names, &merge_msg);
1005
1006
1007 if (!(have_message && !option_log) && merge_msg.len)
1008 strbuf_setlen(&merge_msg, merge_msg.len-1);
1009 }
1010
1011 if (head_invalid || !argc)
1012 usage_with_options(builtin_merge_usage,
1013 builtin_merge_options);
1014
1015 strbuf_addstr(&buf, "merge");
1016 for (i = 0; i < argc; i++)
1017 strbuf_addf(&buf, " %s", argv[i]);
1018 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1019 strbuf_reset(&buf);
1020
1021 for (i = 0; i < argc; i++) {
1022 struct object *o;
1023 struct commit *commit;
1024
1025 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1026 if (!o)
1027 die("%s - not something we can merge", argv[i]);
1028 commit = lookup_commit(o->sha1);
1029 commit->util = (void *)argv[i];
1030 remotes = &commit_list_insert(commit, remotes)->next;
1031
1032 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1033 setenv(buf.buf, argv[i], 1);
1034 strbuf_reset(&buf);
1035 }
1036
1037 if (!use_strategies) {
1038 if (!remoteheads->next)
1039 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1040 else
1041 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1042 }
1043
1044 for (i = 0; i < use_strategies_nr; i++) {
1045 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1046 allow_fast_forward = 0;
1047 if (use_strategies[i]->attr & NO_TRIVIAL)
1048 allow_trivial = 0;
1049 }
1050
1051 if (!remoteheads->next)
1052 common = get_merge_bases(lookup_commit(head),
1053 remoteheads->item, 1);
1054 else {
1055 struct commit_list *list = remoteheads;
1056 commit_list_insert(lookup_commit(head), &list);
1057 common = get_octopus_merge_bases(list);
1058 free(list);
1059 }
1060
1061 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1062 DIE_ON_ERR);
1063
1064 if (!common)
1065 ; /* No common ancestors found. We need a real merge. */
1066 else if (!remoteheads->next && !common->next &&
1067 common->item == remoteheads->item) {
1068 /*
1069 * If head can reach all the merge then we are up to date.
1070 * but first the most common case of merging one remote.
1071 */
1072 finish_up_to_date("Already up-to-date.");
1073 return 0;
1074 } else if (allow_fast_forward && !remoteheads->next &&
1075 !common->next &&
1076 !hashcmp(common->item->object.sha1, head)) {
1077 /* Again the most common case of merging one remote. */
1078 struct strbuf msg = STRBUF_INIT;
1079 struct object *o;
1080 char hex[41];
1081
1082 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1083
1084 if (verbosity >= 0)
1085 printf("Updating %s..%s\n",
1086 hex,
1087 find_unique_abbrev(remoteheads->item->object.sha1,
1088 DEFAULT_ABBREV));
1089 strbuf_addstr(&msg, "Fast-forward");
1090 if (have_message)
1091 strbuf_addstr(&msg,
1092 " (no commit created; -m option ignored)");
1093 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1094 0, NULL, OBJ_COMMIT);
1095 if (!o)
1096 return 1;
1097
1098 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1099 return 1;
1100
1101 finish(o->sha1, msg.buf);
1102 drop_save();
1103 return 0;
1104 } else if (!remoteheads->next && common->next)
1105 ;
1106 /*
1107 * We are not doing octopus and not fast-forward. Need
1108 * a real merge.
1109 */
1110 else if (!remoteheads->next && !common->next && option_commit) {
1111 /*
1112 * We are not doing octopus, not fast-forward, and have
1113 * only one common.
1114 */
1115 refresh_cache(REFRESH_QUIET);
1116 if (allow_trivial && !fast_forward_only) {
1117 /* See if it is really trivial. */
1118 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1119 printf("Trying really trivial in-index merge...\n");
1120 if (!read_tree_trivial(common->item->object.sha1,
1121 head, remoteheads->item->object.sha1))
1122 return merge_trivial();
1123 printf("Nope.\n");
1124 }
1125 } else {
1126 /*
1127 * An octopus. If we can reach all the remote we are up
1128 * to date.
1129 */
1130 int up_to_date = 1;
1131 struct commit_list *j;
1132
1133 for (j = remoteheads; j; j = j->next) {
1134 struct commit_list *common_one;
1135
1136 /*
1137 * Here we *have* to calculate the individual
1138 * merge_bases again, otherwise "git merge HEAD^
1139 * HEAD^^" would be missed.
1140 */
1141 common_one = get_merge_bases(lookup_commit(head),
1142 j->item, 1);
1143 if (hashcmp(common_one->item->object.sha1,
1144 j->item->object.sha1)) {
1145 up_to_date = 0;
1146 break;
1147 }
1148 }
1149 if (up_to_date) {
1150 finish_up_to_date("Already up-to-date. Yeeah!");
1151 return 0;
1152 }
1153 }
1154
1155 if (fast_forward_only)
1156 die("Not possible to fast-forward, aborting.");
1157
1158 /* We are going to make a new commit. */
1159 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1160
1161 /*
1162 * At this point, we need a real merge. No matter what strategy
1163 * we use, it would operate on the index, possibly affecting the
1164 * working tree, and when resolved cleanly, have the desired
1165 * tree in the index -- this means that the index must be in
1166 * sync with the head commit. The strategies are responsible
1167 * to ensure this.
1168 */
1169 if (use_strategies_nr != 1) {
1170 /*
1171 * Stash away the local changes so that we can try more
1172 * than one.
1173 */
1174 save_state();
1175 } else {
1176 memcpy(stash, null_sha1, 20);
1177 }
1178
1179 for (i = 0; i < use_strategies_nr; i++) {
1180 int ret;
1181 if (i) {
1182 printf("Rewinding the tree to pristine...\n");
1183 restore_state();
1184 }
1185 if (use_strategies_nr != 1)
1186 printf("Trying merge strategy %s...\n",
1187 use_strategies[i]->name);
1188 /*
1189 * Remember which strategy left the state in the working
1190 * tree.
1191 */
1192 wt_strategy = use_strategies[i]->name;
1193
1194 ret = try_merge_strategy(use_strategies[i]->name,
1195 common, head_arg);
1196 if (!option_commit && !ret) {
1197 merge_was_ok = 1;
1198 /*
1199 * This is necessary here just to avoid writing
1200 * the tree, but later we will *not* exit with
1201 * status code 1 because merge_was_ok is set.
1202 */
1203 ret = 1;
1204 }
1205
1206 if (ret) {
1207 /*
1208 * The backend exits with 1 when conflicts are
1209 * left to be resolved, with 2 when it does not
1210 * handle the given merge at all.
1211 */
1212 if (ret == 1) {
1213 int cnt = evaluate_result();
1214
1215 if (best_cnt <= 0 || cnt <= best_cnt) {
1216 best_strategy = use_strategies[i]->name;
1217 best_cnt = cnt;
1218 }
1219 }
1220 if (merge_was_ok)
1221 break;
1222 else
1223 continue;
1224 }
1225
1226 /* Automerge succeeded. */
1227 write_tree_trivial(result_tree);
1228 automerge_was_ok = 1;
1229 break;
1230 }
1231
1232 /*
1233 * If we have a resulting tree, that means the strategy module
1234 * auto resolved the merge cleanly.
1235 */
1236 if (automerge_was_ok)
1237 return finish_automerge(common, result_tree, wt_strategy);
1238
1239 /*
1240 * Pick the result from the best strategy and have the user fix
1241 * it up.
1242 */
1243 if (!best_strategy) {
1244 restore_state();
1245 if (use_strategies_nr > 1)
1246 fprintf(stderr,
1247 "No merge strategy handled the merge.\n");
1248 else
1249 fprintf(stderr, "Merge with strategy %s failed.\n",
1250 use_strategies[0]->name);
1251 return 2;
1252 } else if (best_strategy == wt_strategy)
1253 ; /* We already have its result in the working tree. */
1254 else {
1255 printf("Rewinding the tree to pristine...\n");
1256 restore_state();
1257 printf("Using the %s to prepare resolving by hand.\n",
1258 best_strategy);
1259 try_merge_strategy(best_strategy, common, head_arg);
1260 }
1261
1262 if (squash)
1263 finish(NULL, NULL);
1264 else {
1265 int fd;
1266 struct commit_list *j;
1267
1268 for (j = remoteheads; j; j = j->next)
1269 strbuf_addf(&buf, "%s\n",
1270 sha1_to_hex(j->item->object.sha1));
1271 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1272 if (fd < 0)
1273 die_errno("Could not open '%s' for writing",
1274 git_path("MERGE_HEAD"));
1275 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1276 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1277 close(fd);
1278 strbuf_addch(&merge_msg, '\n');
1279 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1280 if (fd < 0)
1281 die_errno("Could not open '%s' for writing",
1282 git_path("MERGE_MSG"));
1283 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1284 merge_msg.len)
1285 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1286 close(fd);
1287 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1288 if (fd < 0)
1289 die_errno("Could not open '%s' for writing",
1290 git_path("MERGE_MODE"));
1291 strbuf_reset(&buf);
1292 if (!allow_fast_forward)
1293 strbuf_addf(&buf, "no-ff");
1294 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1295 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1296 close(fd);
1297 }
1298
1299 if (merge_was_ok) {
1300 fprintf(stderr, "Automatic merge went well; "
1301 "stopped before committing as requested\n");
1302 return 0;
1303 } else
1304 return suggest_conflicts();
1305 }