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