merge: make branch.<name>.mergeoptions correctly override merge.<option>
[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 char *branch_mergeoptions;
58 static int verbosity;
59 static int allow_rerere_auto;
60
61 static struct strategy all_strategy[] = {
62 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
63 { "octopus", DEFAULT_OCTOPUS },
64 { "resolve", 0 },
65 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
66 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
67 };
68
69 static const char *pull_twohead, *pull_octopus;
70
71 static int option_parse_message(const struct option *opt,
72 const char *arg, int unset)
73 {
74 struct strbuf *buf = opt->value;
75
76 if (unset)
77 strbuf_setlen(buf, 0);
78 else if (arg) {
79 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
80 have_message = 1;
81 } else
82 return error("switch `m' requires a value");
83 return 0;
84 }
85
86 static struct strategy *get_strategy(const char *name)
87 {
88 int i;
89 struct strategy *ret;
90 static struct cmdnames main_cmds, other_cmds;
91 static int loaded;
92
93 if (!name)
94 return NULL;
95
96 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
97 if (!strcmp(name, all_strategy[i].name))
98 return &all_strategy[i];
99
100 if (!loaded) {
101 struct cmdnames not_strategies;
102 loaded = 1;
103
104 memset(&not_strategies, 0, sizeof(struct cmdnames));
105 load_command_list("git-merge-", &main_cmds, &other_cmds);
106 for (i = 0; i < main_cmds.cnt; i++) {
107 int j, found = 0;
108 struct cmdname *ent = main_cmds.names[i];
109 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
110 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
111 && !all_strategy[j].name[ent->len])
112 found = 1;
113 if (!found)
114 add_cmdname(&not_strategies, ent->name, ent->len);
115 }
116 exclude_cmds(&main_cmds, &not_strategies);
117 }
118 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
119 fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
120 fprintf(stderr, "Available strategies are:");
121 for (i = 0; i < main_cmds.cnt; i++)
122 fprintf(stderr, " %s", main_cmds.names[i]->name);
123 fprintf(stderr, ".\n");
124 if (other_cmds.cnt) {
125 fprintf(stderr, "Available custom strategies are:");
126 for (i = 0; i < other_cmds.cnt; i++)
127 fprintf(stderr, " %s", other_cmds.names[i]->name);
128 fprintf(stderr, ".\n");
129 }
130 exit(1);
131 }
132
133 ret = xcalloc(1, sizeof(struct strategy));
134 ret->name = xstrdup(name);
135 return ret;
136 }
137
138 static void append_strategy(struct strategy *s)
139 {
140 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
141 use_strategies[use_strategies_nr++] = s;
142 }
143
144 static int option_parse_strategy(const struct option *opt,
145 const char *name, int unset)
146 {
147 if (unset)
148 return 0;
149
150 append_strategy(get_strategy(name));
151 return 0;
152 }
153
154 static int option_parse_x(const struct option *opt,
155 const char *arg, int unset)
156 {
157 if (unset)
158 return 0;
159
160 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
161 xopts[xopts_nr++] = xstrdup(arg);
162 return 0;
163 }
164
165 static int option_parse_n(const struct option *opt,
166 const char *arg, int unset)
167 {
168 show_diffstat = unset;
169 return 0;
170 }
171
172 static struct option builtin_merge_options[] = {
173 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
174 "do not show a diffstat at the end of the merge",
175 PARSE_OPT_NOARG, option_parse_n },
176 OPT_BOOLEAN(0, "stat", &show_diffstat,
177 "show a diffstat at the end of the merge"),
178 OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
179 OPT_BOOLEAN(0, "log", &option_log,
180 "add list of one-line log to merge commit message"),
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, 0, 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 void parse_branch_merge_options(char *bmo)
479 {
480 const char **argv;
481 int argc;
482
483 if (!bmo)
484 return;
485 argc = split_cmdline(bmo, &argv);
486 if (argc < 0)
487 die("Bad branch.%s.mergeoptions string", branch);
488 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
489 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
490 argc++;
491 argv[0] = "branch.*.mergeoptions";
492 parse_options(argc, argv, NULL, builtin_merge_options,
493 builtin_merge_usage, 0);
494 free(argv);
495 }
496
497 static int git_merge_config(const char *k, const char *v, void *cb)
498 {
499 if (branch && !prefixcmp(k, "branch.") &&
500 !prefixcmp(k + 7, branch) &&
501 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
502 free(branch_mergeoptions);
503 branch_mergeoptions = xstrdup(v);
504 return 0;
505 }
506
507 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
508 show_diffstat = git_config_bool(k, v);
509 else if (!strcmp(k, "pull.twohead"))
510 return git_config_string(&pull_twohead, k, v);
511 else if (!strcmp(k, "pull.octopus"))
512 return git_config_string(&pull_octopus, k, v);
513 else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
514 option_log = git_config_bool(k, v);
515 return git_diff_ui_config(k, v, cb);
516 }
517
518 static int read_tree_trivial(unsigned char *common, unsigned char *head,
519 unsigned char *one)
520 {
521 int i, nr_trees = 0;
522 struct tree *trees[MAX_UNPACK_TREES];
523 struct tree_desc t[MAX_UNPACK_TREES];
524 struct unpack_trees_options opts;
525
526 memset(&opts, 0, sizeof(opts));
527 opts.head_idx = 2;
528 opts.src_index = &the_index;
529 opts.dst_index = &the_index;
530 opts.update = 1;
531 opts.verbose_update = 1;
532 opts.trivial_merges_only = 1;
533 opts.merge = 1;
534 trees[nr_trees] = parse_tree_indirect(common);
535 if (!trees[nr_trees++])
536 return -1;
537 trees[nr_trees] = parse_tree_indirect(head);
538 if (!trees[nr_trees++])
539 return -1;
540 trees[nr_trees] = parse_tree_indirect(one);
541 if (!trees[nr_trees++])
542 return -1;
543 opts.fn = threeway_merge;
544 cache_tree_free(&active_cache_tree);
545 for (i = 0; i < nr_trees; i++) {
546 parse_tree(trees[i]);
547 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
548 }
549 if (unpack_trees(nr_trees, t, &opts))
550 return -1;
551 return 0;
552 }
553
554 static void write_tree_trivial(unsigned char *sha1)
555 {
556 if (write_cache_as_tree(sha1, 0, NULL))
557 die("git write-tree failed to write a tree");
558 }
559
560 static int try_merge_strategy(const char *strategy, struct commit_list *common,
561 const char *head_arg)
562 {
563 const char **args;
564 int i = 0, x = 0, ret;
565 struct commit_list *j;
566 struct strbuf buf = STRBUF_INIT;
567 int index_fd;
568 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
569
570 index_fd = hold_locked_index(lock, 1);
571 refresh_cache(REFRESH_QUIET);
572 if (active_cache_changed &&
573 (write_cache(index_fd, active_cache, active_nr) ||
574 commit_locked_index(lock)))
575 return error("Unable to write index.");
576 rollback_lock_file(lock);
577
578 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
579 int clean;
580 struct commit *result;
581 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
582 int index_fd;
583 struct commit_list *reversed = NULL;
584 struct merge_options o;
585
586 if (remoteheads->next) {
587 error("Not handling anything other than two heads merge.");
588 return 2;
589 }
590
591 init_merge_options(&o);
592 if (!strcmp(strategy, "subtree"))
593 o.subtree_shift = "";
594
595 for (x = 0; x < xopts_nr; x++) {
596 if (!strcmp(xopts[x], "ours"))
597 o.recursive_variant = MERGE_RECURSIVE_OURS;
598 else if (!strcmp(xopts[x], "theirs"))
599 o.recursive_variant = MERGE_RECURSIVE_THEIRS;
600 else if (!strcmp(xopts[x], "subtree"))
601 o.subtree_shift = "";
602 else if (!prefixcmp(xopts[x], "subtree="))
603 o.subtree_shift = xopts[x]+8;
604 else
605 die("Unknown option for merge-recursive: -X%s", xopts[x]);
606 }
607
608 o.branch1 = head_arg;
609 o.branch2 = remoteheads->item->util;
610
611 for (j = common; j; j = j->next)
612 commit_list_insert(j->item, &reversed);
613
614 index_fd = hold_locked_index(lock, 1);
615 clean = merge_recursive(&o, lookup_commit(head),
616 remoteheads->item, reversed, &result);
617 if (active_cache_changed &&
618 (write_cache(index_fd, active_cache, active_nr) ||
619 commit_locked_index(lock)))
620 die ("unable to write %s", get_index_file());
621 rollback_lock_file(lock);
622 return clean ? 0 : 1;
623 } else {
624 args = xmalloc((4 + xopts_nr + commit_list_count(common) +
625 commit_list_count(remoteheads)) * sizeof(char *));
626 strbuf_addf(&buf, "merge-%s", strategy);
627 args[i++] = buf.buf;
628 for (x = 0; x < xopts_nr; x++) {
629 char *s = xmalloc(strlen(xopts[x])+2+1);
630 strcpy(s, "--");
631 strcpy(s+2, xopts[x]);
632 args[i++] = s;
633 }
634 for (j = common; j; j = j->next)
635 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
636 args[i++] = "--";
637 args[i++] = head_arg;
638 for (j = remoteheads; j; j = j->next)
639 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
640 args[i] = NULL;
641 ret = run_command_v_opt(args, RUN_GIT_CMD);
642 strbuf_release(&buf);
643 i = 1;
644 for (x = 0; x < xopts_nr; x++)
645 free((void *)args[i++]);
646 for (j = common; j; j = j->next)
647 free((void *)args[i++]);
648 i += 2;
649 for (j = remoteheads; j; j = j->next)
650 free((void *)args[i++]);
651 free(args);
652 discard_cache();
653 if (read_cache() < 0)
654 die("failed to read the cache");
655 resolve_undo_clear();
656 return ret;
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 static int checkout_fast_forward(unsigned char *head, 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 if (branch_mergeoptions)
931 parse_branch_merge_options(branch_mergeoptions);
932 argc = parse_options(argc, argv, prefix, builtin_merge_options,
933 builtin_merge_usage, 0);
934 if (verbosity < 0)
935 show_diffstat = 0;
936
937 if (squash) {
938 if (!allow_fast_forward)
939 die("You cannot combine --squash with --no-ff.");
940 option_commit = 0;
941 }
942
943 if (!allow_fast_forward && fast_forward_only)
944 die("You cannot combine --no-ff with --ff-only.");
945
946 if (!argc)
947 usage_with_options(builtin_merge_usage,
948 builtin_merge_options);
949
950 /*
951 * This could be traditional "merge <msg> HEAD <commit>..." and
952 * the way we can tell it is to see if the second token is HEAD,
953 * but some people might have misused the interface and used a
954 * committish that is the same as HEAD there instead.
955 * Traditional format never would have "-m" so it is an
956 * additional safety measure to check for it.
957 */
958
959 if (!have_message && is_old_style_invocation(argc, argv)) {
960 strbuf_addstr(&merge_msg, argv[0]);
961 head_arg = argv[1];
962 argv += 2;
963 argc -= 2;
964 } else if (head_invalid) {
965 struct object *remote_head;
966 /*
967 * If the merged head is a valid one there is no reason
968 * to forbid "git merge" into a branch yet to be born.
969 * We do the same for "git pull".
970 */
971 if (argc != 1)
972 die("Can merge only exactly one commit into "
973 "empty head");
974 if (squash)
975 die("Squash commit into empty head not supported yet");
976 if (!allow_fast_forward)
977 die("Non-fast-forward commit does not make sense into "
978 "an empty head");
979 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
980 if (!remote_head)
981 die("%s - not something we can merge", argv[0]);
982 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
983 DIE_ON_ERR);
984 reset_hard(remote_head->sha1, 0);
985 return 0;
986 } else {
987 struct strbuf msg = STRBUF_INIT;
988
989 /* We are invoked directly as the first-class UI. */
990 head_arg = "HEAD";
991
992 /*
993 * All the rest are the commits being merged;
994 * prepare the standard merge summary message to
995 * be appended to the given message. If remote
996 * is invalid we will die later in the common
997 * codepath so we discard the error in this
998 * loop.
999 */
1000 if (!have_message) {
1001 for (i = 0; i < argc; i++)
1002 merge_name(argv[i], &msg);
1003 fmt_merge_msg(option_log, &msg, &merge_msg);
1004 if (merge_msg.len)
1005 strbuf_setlen(&merge_msg, merge_msg.len-1);
1006 }
1007 }
1008
1009 if (head_invalid || !argc)
1010 usage_with_options(builtin_merge_usage,
1011 builtin_merge_options);
1012
1013 strbuf_addstr(&buf, "merge");
1014 for (i = 0; i < argc; i++)
1015 strbuf_addf(&buf, " %s", argv[i]);
1016 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1017 strbuf_reset(&buf);
1018
1019 for (i = 0; i < argc; i++) {
1020 struct object *o;
1021 struct commit *commit;
1022
1023 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
1024 if (!o)
1025 die("%s - not something we can merge", argv[i]);
1026 commit = lookup_commit(o->sha1);
1027 commit->util = (void *)argv[i];
1028 remotes = &commit_list_insert(commit, remotes)->next;
1029
1030 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
1031 setenv(buf.buf, argv[i], 1);
1032 strbuf_reset(&buf);
1033 }
1034
1035 if (!use_strategies) {
1036 if (!remoteheads->next)
1037 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1038 else
1039 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1040 }
1041
1042 for (i = 0; i < use_strategies_nr; i++) {
1043 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1044 allow_fast_forward = 0;
1045 if (use_strategies[i]->attr & NO_TRIVIAL)
1046 allow_trivial = 0;
1047 }
1048
1049 if (!remoteheads->next)
1050 common = get_merge_bases(lookup_commit(head),
1051 remoteheads->item, 1);
1052 else {
1053 struct commit_list *list = remoteheads;
1054 commit_list_insert(lookup_commit(head), &list);
1055 common = get_octopus_merge_bases(list);
1056 free(list);
1057 }
1058
1059 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
1060 DIE_ON_ERR);
1061
1062 if (!common)
1063 ; /* No common ancestors found. We need a real merge. */
1064 else if (!remoteheads->next && !common->next &&
1065 common->item == remoteheads->item) {
1066 /*
1067 * If head can reach all the merge then we are up to date.
1068 * but first the most common case of merging one remote.
1069 */
1070 finish_up_to_date("Already up-to-date.");
1071 return 0;
1072 } else if (allow_fast_forward && !remoteheads->next &&
1073 !common->next &&
1074 !hashcmp(common->item->object.sha1, head)) {
1075 /* Again the most common case of merging one remote. */
1076 struct strbuf msg = STRBUF_INIT;
1077 struct object *o;
1078 char hex[41];
1079
1080 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
1081
1082 if (verbosity >= 0)
1083 printf("Updating %s..%s\n",
1084 hex,
1085 find_unique_abbrev(remoteheads->item->object.sha1,
1086 DEFAULT_ABBREV));
1087 strbuf_addstr(&msg, "Fast-forward");
1088 if (have_message)
1089 strbuf_addstr(&msg,
1090 " (no commit created; -m option ignored)");
1091 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
1092 0, NULL, OBJ_COMMIT);
1093 if (!o)
1094 return 1;
1095
1096 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
1097 return 1;
1098
1099 finish(o->sha1, msg.buf);
1100 drop_save();
1101 return 0;
1102 } else if (!remoteheads->next && common->next)
1103 ;
1104 /*
1105 * We are not doing octopus and not fast-forward. Need
1106 * a real merge.
1107 */
1108 else if (!remoteheads->next && !common->next && option_commit) {
1109 /*
1110 * We are not doing octopus, not fast-forward, and have
1111 * only one common.
1112 */
1113 refresh_cache(REFRESH_QUIET);
1114 if (allow_trivial && !fast_forward_only) {
1115 /* See if it is really trivial. */
1116 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1117 printf("Trying really trivial in-index merge...\n");
1118 if (!read_tree_trivial(common->item->object.sha1,
1119 head, remoteheads->item->object.sha1))
1120 return merge_trivial();
1121 printf("Nope.\n");
1122 }
1123 } else {
1124 /*
1125 * An octopus. If we can reach all the remote we are up
1126 * to date.
1127 */
1128 int up_to_date = 1;
1129 struct commit_list *j;
1130
1131 for (j = remoteheads; j; j = j->next) {
1132 struct commit_list *common_one;
1133
1134 /*
1135 * Here we *have* to calculate the individual
1136 * merge_bases again, otherwise "git merge HEAD^
1137 * HEAD^^" would be missed.
1138 */
1139 common_one = get_merge_bases(lookup_commit(head),
1140 j->item, 1);
1141 if (hashcmp(common_one->item->object.sha1,
1142 j->item->object.sha1)) {
1143 up_to_date = 0;
1144 break;
1145 }
1146 }
1147 if (up_to_date) {
1148 finish_up_to_date("Already up-to-date. Yeeah!");
1149 return 0;
1150 }
1151 }
1152
1153 if (fast_forward_only)
1154 die("Not possible to fast-forward, aborting.");
1155
1156 /* We are going to make a new commit. */
1157 git_committer_info(IDENT_ERROR_ON_NO_NAME);
1158
1159 /*
1160 * At this point, we need a real merge. No matter what strategy
1161 * we use, it would operate on the index, possibly affecting the
1162 * working tree, and when resolved cleanly, have the desired
1163 * tree in the index -- this means that the index must be in
1164 * sync with the head commit. The strategies are responsible
1165 * to ensure this.
1166 */
1167 if (use_strategies_nr != 1) {
1168 /*
1169 * Stash away the local changes so that we can try more
1170 * than one.
1171 */
1172 save_state();
1173 } else {
1174 memcpy(stash, null_sha1, 20);
1175 }
1176
1177 for (i = 0; i < use_strategies_nr; i++) {
1178 int ret;
1179 if (i) {
1180 printf("Rewinding the tree to pristine...\n");
1181 restore_state();
1182 }
1183 if (use_strategies_nr != 1)
1184 printf("Trying merge strategy %s...\n",
1185 use_strategies[i]->name);
1186 /*
1187 * Remember which strategy left the state in the working
1188 * tree.
1189 */
1190 wt_strategy = use_strategies[i]->name;
1191
1192 ret = try_merge_strategy(use_strategies[i]->name,
1193 common, head_arg);
1194 if (!option_commit && !ret) {
1195 merge_was_ok = 1;
1196 /*
1197 * This is necessary here just to avoid writing
1198 * the tree, but later we will *not* exit with
1199 * status code 1 because merge_was_ok is set.
1200 */
1201 ret = 1;
1202 }
1203
1204 if (ret) {
1205 /*
1206 * The backend exits with 1 when conflicts are
1207 * left to be resolved, with 2 when it does not
1208 * handle the given merge at all.
1209 */
1210 if (ret == 1) {
1211 int cnt = evaluate_result();
1212
1213 if (best_cnt <= 0 || cnt <= best_cnt) {
1214 best_strategy = use_strategies[i]->name;
1215 best_cnt = cnt;
1216 }
1217 }
1218 if (merge_was_ok)
1219 break;
1220 else
1221 continue;
1222 }
1223
1224 /* Automerge succeeded. */
1225 write_tree_trivial(result_tree);
1226 automerge_was_ok = 1;
1227 break;
1228 }
1229
1230 /*
1231 * If we have a resulting tree, that means the strategy module
1232 * auto resolved the merge cleanly.
1233 */
1234 if (automerge_was_ok)
1235 return finish_automerge(common, result_tree, wt_strategy);
1236
1237 /*
1238 * Pick the result from the best strategy and have the user fix
1239 * it up.
1240 */
1241 if (!best_strategy) {
1242 restore_state();
1243 if (use_strategies_nr > 1)
1244 fprintf(stderr,
1245 "No merge strategy handled the merge.\n");
1246 else
1247 fprintf(stderr, "Merge with strategy %s failed.\n",
1248 use_strategies[0]->name);
1249 return 2;
1250 } else if (best_strategy == wt_strategy)
1251 ; /* We already have its result in the working tree. */
1252 else {
1253 printf("Rewinding the tree to pristine...\n");
1254 restore_state();
1255 printf("Using the %s to prepare resolving by hand.\n",
1256 best_strategy);
1257 try_merge_strategy(best_strategy, common, head_arg);
1258 }
1259
1260 if (squash)
1261 finish(NULL, NULL);
1262 else {
1263 int fd;
1264 struct commit_list *j;
1265
1266 for (j = remoteheads; j; j = j->next)
1267 strbuf_addf(&buf, "%s\n",
1268 sha1_to_hex(j->item->object.sha1));
1269 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1270 if (fd < 0)
1271 die_errno("Could not open '%s' for writing",
1272 git_path("MERGE_HEAD"));
1273 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1274 die_errno("Could not write to '%s'", git_path("MERGE_HEAD"));
1275 close(fd);
1276 strbuf_addch(&merge_msg, '\n');
1277 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1278 if (fd < 0)
1279 die_errno("Could not open '%s' for writing",
1280 git_path("MERGE_MSG"));
1281 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1282 merge_msg.len)
1283 die_errno("Could not write to '%s'", git_path("MERGE_MSG"));
1284 close(fd);
1285 fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
1286 if (fd < 0)
1287 die_errno("Could not open '%s' for writing",
1288 git_path("MERGE_MODE"));
1289 strbuf_reset(&buf);
1290 if (!allow_fast_forward)
1291 strbuf_addf(&buf, "no-ff");
1292 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1293 die_errno("Could not write to '%s'", git_path("MERGE_MODE"));
1294 close(fd);
1295 }
1296
1297 if (merge_was_ok) {
1298 fprintf(stderr, "Automatic merge went well; "
1299 "stopped before committing as requested\n");
1300 return 0;
1301 } else
1302 return suggest_conflicts();
1303 }