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#include "remote.h"
29#include "fmt-merge-msg.h"
30#include "gpg-interface.h"
31
32#define DEFAULT_TWOHEAD (1<<0)
33#define DEFAULT_OCTOPUS (1<<1)
34#define NO_FAST_FORWARD (1<<2)
35#define NO_TRIVIAL (1<<3)
36
37struct strategy {
38 const char *name;
39 unsigned attr;
40};
41
42static const char * const builtin_merge_usage[] = {
43 N_("git merge [options] [<commit>...]"),
44 N_("git merge [options] <msg> HEAD <commit>"),
45 N_("git merge --abort"),
46 NULL
47};
48
49static int show_diffstat = 1, shortlog_len = -1, squash;
50static int option_commit = 1;
51static int option_edit = -1;
52static int allow_trivial = 1, have_message, verify_signatures;
53static int overwrite_ignore = 1;
54static struct strbuf merge_msg = STRBUF_INIT;
55static struct strategy **use_strategies;
56static size_t use_strategies_nr, use_strategies_alloc;
57static const char **xopts;
58static size_t xopts_nr, xopts_alloc;
59static const char *branch;
60static char *branch_mergeoptions;
61static int option_renormalize;
62static int verbosity;
63static int allow_rerere_auto;
64static int abort_current_merge;
65static int show_progress = -1;
66static int default_to_upstream;
67static const char *sign_commit;
68
69static struct strategy all_strategy[] = {
70 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
71 { "octopus", DEFAULT_OCTOPUS },
72 { "resolve", 0 },
73 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
74 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
75};
76
77static const char *pull_twohead, *pull_octopus;
78
79enum ff_type {
80 FF_NO,
81 FF_ALLOW,
82 FF_ONLY
83};
84
85static enum ff_type fast_forward = FF_ALLOW;
86
87static int option_parse_message(const struct option *opt,
88 const char *arg, int unset)
89{
90 struct strbuf *buf = opt->value;
91
92 if (unset)
93 strbuf_setlen(buf, 0);
94 else if (arg) {
95 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
96 have_message = 1;
97 } else
98 return error(_("switch `m' requires a value"));
99 return 0;
100}
101
102static struct strategy *get_strategy(const char *name)
103{
104 int i;
105 struct strategy *ret;
106 static struct cmdnames main_cmds, other_cmds;
107 static int loaded;
108
109 if (!name)
110 return NULL;
111
112 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
113 if (!strcmp(name, all_strategy[i].name))
114 return &all_strategy[i];
115
116 if (!loaded) {
117 struct cmdnames not_strategies;
118 loaded = 1;
119
120 memset(¬_strategies, 0, sizeof(struct cmdnames));
121 load_command_list("git-merge-", &main_cmds, &other_cmds);
122 for (i = 0; i < main_cmds.cnt; i++) {
123 int j, found = 0;
124 struct cmdname *ent = main_cmds.names[i];
125 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
126 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
127 && !all_strategy[j].name[ent->len])
128 found = 1;
129 if (!found)
130 add_cmdname(¬_strategies, ent->name, ent->len);
131 }
132 exclude_cmds(&main_cmds, ¬_strategies);
133 }
134 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
135 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
136 fprintf(stderr, _("Available strategies are:"));
137 for (i = 0; i < main_cmds.cnt; i++)
138 fprintf(stderr, " %s", main_cmds.names[i]->name);
139 fprintf(stderr, ".\n");
140 if (other_cmds.cnt) {
141 fprintf(stderr, _("Available custom strategies are:"));
142 for (i = 0; i < other_cmds.cnt; i++)
143 fprintf(stderr, " %s", other_cmds.names[i]->name);
144 fprintf(stderr, ".\n");
145 }
146 exit(1);
147 }
148
149 ret = xcalloc(1, sizeof(struct strategy));
150 ret->name = xstrdup(name);
151 ret->attr = NO_TRIVIAL;
152 return ret;
153}
154
155static void append_strategy(struct strategy *s)
156{
157 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
158 use_strategies[use_strategies_nr++] = s;
159}
160
161static int option_parse_strategy(const struct option *opt,
162 const char *name, int unset)
163{
164 if (unset)
165 return 0;
166
167 append_strategy(get_strategy(name));
168 return 0;
169}
170
171static int option_parse_x(const struct option *opt,
172 const char *arg, int unset)
173{
174 if (unset)
175 return 0;
176
177 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
178 xopts[xopts_nr++] = xstrdup(arg);
179 return 0;
180}
181
182static int option_parse_n(const struct option *opt,
183 const char *arg, int unset)
184{
185 show_diffstat = unset;
186 return 0;
187}
188
189static struct option builtin_merge_options[] = {
190 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
191 N_("do not show a diffstat at the end of the merge"),
192 PARSE_OPT_NOARG, option_parse_n },
193 OPT_BOOL(0, "stat", &show_diffstat,
194 N_("show a diffstat at the end of the merge")),
195 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
196 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
197 N_("add (at most <n>) entries from shortlog to merge commit message"),
198 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
199 OPT_BOOL(0, "squash", &squash,
200 N_("create a single commit instead of doing a merge")),
201 OPT_BOOL(0, "commit", &option_commit,
202 N_("perform a commit if the merge succeeds (default)")),
203 OPT_BOOL('e', "edit", &option_edit,
204 N_("edit message before committing")),
205 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
206 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
207 N_("abort if fast-forward is not possible"),
208 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
209 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
210 OPT_BOOL(0, "verify-signatures", &verify_signatures,
211 N_("Verify that the named commit has a valid GPG signature")),
212 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
213 N_("merge strategy to use"), option_parse_strategy),
214 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
215 N_("option for selected merge strategy"), option_parse_x),
216 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
217 N_("merge commit message (for a non-fast-forward merge)"),
218 option_parse_message),
219 OPT__VERBOSITY(&verbosity),
220 OPT_BOOL(0, "abort", &abort_current_merge,
221 N_("abort the current in-progress merge")),
222 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
223 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
224 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
225 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
226 OPT_END()
227};
228
229/* Cleans up metadata that is uninteresting after a succeeded merge. */
230static void drop_save(void)
231{
232 unlink(git_path("MERGE_HEAD"));
233 unlink(git_path("MERGE_MSG"));
234 unlink(git_path("MERGE_MODE"));
235}
236
237static int save_state(unsigned char *stash)
238{
239 int len;
240 struct child_process cp;
241 struct strbuf buffer = STRBUF_INIT;
242 const char *argv[] = {"stash", "create", NULL};
243
244 memset(&cp, 0, sizeof(cp));
245 cp.argv = argv;
246 cp.out = -1;
247 cp.git_cmd = 1;
248
249 if (start_command(&cp))
250 die(_("could not run stash."));
251 len = strbuf_read(&buffer, cp.out, 1024);
252 close(cp.out);
253
254 if (finish_command(&cp) || len < 0)
255 die(_("stash failed"));
256 else if (!len) /* no changes */
257 return -1;
258 strbuf_setlen(&buffer, buffer.len-1);
259 if (get_sha1(buffer.buf, stash))
260 die(_("not a valid object: %s"), buffer.buf);
261 return 0;
262}
263
264static void read_empty(unsigned const char *sha1, int verbose)
265{
266 int i = 0;
267 const char *args[7];
268
269 args[i++] = "read-tree";
270 if (verbose)
271 args[i++] = "-v";
272 args[i++] = "-m";
273 args[i++] = "-u";
274 args[i++] = EMPTY_TREE_SHA1_HEX;
275 args[i++] = sha1_to_hex(sha1);
276 args[i] = NULL;
277
278 if (run_command_v_opt(args, RUN_GIT_CMD))
279 die(_("read-tree failed"));
280}
281
282static void reset_hard(unsigned const char *sha1, int verbose)
283{
284 int i = 0;
285 const char *args[6];
286
287 args[i++] = "read-tree";
288 if (verbose)
289 args[i++] = "-v";
290 args[i++] = "--reset";
291 args[i++] = "-u";
292 args[i++] = sha1_to_hex(sha1);
293 args[i] = NULL;
294
295 if (run_command_v_opt(args, RUN_GIT_CMD))
296 die(_("read-tree failed"));
297}
298
299static void restore_state(const unsigned char *head,
300 const unsigned char *stash)
301{
302 struct strbuf sb = STRBUF_INIT;
303 const char *args[] = { "stash", "apply", NULL, NULL };
304
305 if (is_null_sha1(stash))
306 return;
307
308 reset_hard(head, 1);
309
310 args[2] = sha1_to_hex(stash);
311
312 /*
313 * It is OK to ignore error here, for example when there was
314 * nothing to restore.
315 */
316 run_command_v_opt(args, RUN_GIT_CMD);
317
318 strbuf_release(&sb);
319 refresh_cache(REFRESH_QUIET);
320}
321
322/* This is called when no merge was necessary. */
323static void finish_up_to_date(const char *msg)
324{
325 if (verbosity >= 0)
326 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
327 drop_save();
328}
329
330static void squash_message(struct commit *commit, struct commit_list *remoteheads)
331{
332 struct rev_info rev;
333 struct strbuf out = STRBUF_INIT;
334 struct commit_list *j;
335 const char *filename;
336 int fd;
337 struct pretty_print_context ctx = {0};
338
339 printf(_("Squash commit -- not updating HEAD\n"));
340 filename = git_path("SQUASH_MSG");
341 fd = open(filename, O_WRONLY | O_CREAT, 0666);
342 if (fd < 0)
343 die_errno(_("Could not write to '%s'"), filename);
344
345 init_revisions(&rev, NULL);
346 rev.ignore_merges = 1;
347 rev.commit_format = CMIT_FMT_MEDIUM;
348
349 commit->object.flags |= UNINTERESTING;
350 add_pending_object(&rev, &commit->object, NULL);
351
352 for (j = remoteheads; j; j = j->next)
353 add_pending_object(&rev, &j->item->object, NULL);
354
355 setup_revisions(0, NULL, &rev, NULL);
356 if (prepare_revision_walk(&rev))
357 die(_("revision walk setup failed"));
358
359 ctx.abbrev = rev.abbrev;
360 ctx.date_mode = rev.date_mode;
361 ctx.fmt = rev.commit_format;
362
363 strbuf_addstr(&out, "Squashed commit of the following:\n");
364 while ((commit = get_revision(&rev)) != NULL) {
365 strbuf_addch(&out, '\n');
366 strbuf_addf(&out, "commit %s\n",
367 sha1_to_hex(commit->object.sha1));
368 pretty_print_commit(&ctx, commit, &out);
369 }
370 if (write_in_full(fd, out.buf, out.len) != out.len)
371 die_errno(_("Writing SQUASH_MSG"));
372 if (close(fd))
373 die_errno(_("Finishing SQUASH_MSG"));
374 strbuf_release(&out);
375}
376
377static void finish(struct commit *head_commit,
378 struct commit_list *remoteheads,
379 const unsigned char *new_head, const char *msg)
380{
381 struct strbuf reflog_message = STRBUF_INIT;
382 const unsigned char *head = head_commit->object.sha1;
383
384 if (!msg)
385 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
386 else {
387 if (verbosity >= 0)
388 printf("%s\n", msg);
389 strbuf_addf(&reflog_message, "%s: %s",
390 getenv("GIT_REFLOG_ACTION"), msg);
391 }
392 if (squash) {
393 squash_message(head_commit, remoteheads);
394 } else {
395 if (verbosity >= 0 && !merge_msg.len)
396 printf(_("No merge message -- not updating HEAD\n"));
397 else {
398 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
399 update_ref(reflog_message.buf, "HEAD",
400 new_head, head, 0,
401 DIE_ON_ERR);
402 /*
403 * We ignore errors in 'gc --auto', since the
404 * user should see them.
405 */
406 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
407 }
408 }
409 if (new_head && show_diffstat) {
410 struct diff_options opts;
411 diff_setup(&opts);
412 opts.stat_width = -1; /* use full terminal width */
413 opts.stat_graph_width = -1; /* respect statGraphWidth config */
414 opts.output_format |=
415 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
416 opts.detect_rename = DIFF_DETECT_RENAME;
417 diff_setup_done(&opts);
418 diff_tree_sha1(head, new_head, "", &opts);
419 diffcore_std(&opts);
420 diff_flush(&opts);
421 }
422
423 /* Run a post-merge hook */
424 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
425
426 strbuf_release(&reflog_message);
427}
428
429/* Get the name for the merge commit's message. */
430static void merge_name(const char *remote, struct strbuf *msg)
431{
432 struct commit *remote_head;
433 unsigned char branch_head[20];
434 struct strbuf buf = STRBUF_INIT;
435 struct strbuf bname = STRBUF_INIT;
436 const char *ptr;
437 char *found_ref;
438 int len, early;
439
440 strbuf_branchname(&bname, remote);
441 remote = bname.buf;
442
443 memset(branch_head, 0, sizeof(branch_head));
444 remote_head = get_merge_parent(remote);
445 if (!remote_head)
446 die(_("'%s' does not point to a commit"), remote);
447
448 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
449 if (starts_with(found_ref, "refs/heads/")) {
450 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
451 sha1_to_hex(branch_head), remote);
452 goto cleanup;
453 }
454 if (starts_with(found_ref, "refs/tags/")) {
455 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
456 sha1_to_hex(branch_head), remote);
457 goto cleanup;
458 }
459 if (starts_with(found_ref, "refs/remotes/")) {
460 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
461 sha1_to_hex(branch_head), remote);
462 goto cleanup;
463 }
464 }
465
466 /* See if remote matches <name>^^^.. or <name>~<number> */
467 for (len = 0, ptr = remote + strlen(remote);
468 remote < ptr && ptr[-1] == '^';
469 ptr--)
470 len++;
471 if (len)
472 early = 1;
473 else {
474 early = 0;
475 ptr = strrchr(remote, '~');
476 if (ptr) {
477 int seen_nonzero = 0;
478
479 len++; /* count ~ */
480 while (*++ptr && isdigit(*ptr)) {
481 seen_nonzero |= (*ptr != '0');
482 len++;
483 }
484 if (*ptr)
485 len = 0; /* not ...~<number> */
486 else if (seen_nonzero)
487 early = 1;
488 else if (len == 1)
489 early = 1; /* "name~" is "name~1"! */
490 }
491 }
492 if (len) {
493 struct strbuf truname = STRBUF_INIT;
494 strbuf_addstr(&truname, "refs/heads/");
495 strbuf_addstr(&truname, remote);
496 strbuf_setlen(&truname, truname.len - len);
497 if (ref_exists(truname.buf)) {
498 strbuf_addf(msg,
499 "%s\t\tbranch '%s'%s of .\n",
500 sha1_to_hex(remote_head->object.sha1),
501 truname.buf + 11,
502 (early ? " (early part)" : ""));
503 strbuf_release(&truname);
504 goto cleanup;
505 }
506 }
507
508 if (!strcmp(remote, "FETCH_HEAD") &&
509 !access(git_path("FETCH_HEAD"), R_OK)) {
510 const char *filename;
511 FILE *fp;
512 struct strbuf line = STRBUF_INIT;
513 char *ptr;
514
515 filename = git_path("FETCH_HEAD");
516 fp = fopen(filename, "r");
517 if (!fp)
518 die_errno(_("could not open '%s' for reading"),
519 filename);
520 strbuf_getline(&line, fp, '\n');
521 fclose(fp);
522 ptr = strstr(line.buf, "\tnot-for-merge\t");
523 if (ptr)
524 strbuf_remove(&line, ptr-line.buf+1, 13);
525 strbuf_addbuf(msg, &line);
526 strbuf_release(&line);
527 goto cleanup;
528 }
529
530 if (remote_head->util) {
531 struct merge_remote_desc *desc;
532 desc = merge_remote_util(remote_head);
533 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
534 strbuf_addf(msg, "%s\t\t%s '%s'\n",
535 sha1_to_hex(desc->obj->sha1),
536 typename(desc->obj->type),
537 remote);
538 goto cleanup;
539 }
540 }
541
542 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
543 sha1_to_hex(remote_head->object.sha1), remote);
544cleanup:
545 strbuf_release(&buf);
546 strbuf_release(&bname);
547}
548
549static void parse_branch_merge_options(char *bmo)
550{
551 const char **argv;
552 int argc;
553
554 if (!bmo)
555 return;
556 argc = split_cmdline(bmo, &argv);
557 if (argc < 0)
558 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
559 split_cmdline_strerror(argc));
560 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
561 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
562 argc++;
563 argv[0] = "branch.*.mergeoptions";
564 parse_options(argc, argv, NULL, builtin_merge_options,
565 builtin_merge_usage, 0);
566 free(argv);
567}
568
569static int git_merge_config(const char *k, const char *v, void *cb)
570{
571 int status;
572
573 if (branch && starts_with(k, "branch.") &&
574 starts_with(k + 7, branch) &&
575 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
576 free(branch_mergeoptions);
577 branch_mergeoptions = xstrdup(v);
578 return 0;
579 }
580
581 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
582 show_diffstat = git_config_bool(k, v);
583 else if (!strcmp(k, "pull.twohead"))
584 return git_config_string(&pull_twohead, k, v);
585 else if (!strcmp(k, "pull.octopus"))
586 return git_config_string(&pull_octopus, k, v);
587 else if (!strcmp(k, "merge.renormalize"))
588 option_renormalize = git_config_bool(k, v);
589 else if (!strcmp(k, "merge.ff")) {
590 int boolval = git_config_maybe_bool(k, v);
591 if (0 <= boolval) {
592 fast_forward = boolval ? FF_ALLOW : FF_NO;
593 } else if (v && !strcmp(v, "only")) {
594 fast_forward = FF_ONLY;
595 } /* do not barf on values from future versions of git */
596 return 0;
597 } else if (!strcmp(k, "merge.defaulttoupstream")) {
598 default_to_upstream = git_config_bool(k, v);
599 return 0;
600 } else if (!strcmp(k, "commit.gpgsign")) {
601 sign_commit = git_config_bool(k, v) ? "" : NULL;
602 return 0;
603 }
604
605 status = fmt_merge_msg_config(k, v, cb);
606 if (status)
607 return status;
608 status = git_gpg_config(k, v, NULL);
609 if (status)
610 return status;
611 return git_diff_ui_config(k, v, cb);
612}
613
614static int read_tree_trivial(unsigned char *common, unsigned char *head,
615 unsigned char *one)
616{
617 int i, nr_trees = 0;
618 struct tree *trees[MAX_UNPACK_TREES];
619 struct tree_desc t[MAX_UNPACK_TREES];
620 struct unpack_trees_options opts;
621
622 memset(&opts, 0, sizeof(opts));
623 opts.head_idx = 2;
624 opts.src_index = &the_index;
625 opts.dst_index = &the_index;
626 opts.update = 1;
627 opts.verbose_update = 1;
628 opts.trivial_merges_only = 1;
629 opts.merge = 1;
630 trees[nr_trees] = parse_tree_indirect(common);
631 if (!trees[nr_trees++])
632 return -1;
633 trees[nr_trees] = parse_tree_indirect(head);
634 if (!trees[nr_trees++])
635 return -1;
636 trees[nr_trees] = parse_tree_indirect(one);
637 if (!trees[nr_trees++])
638 return -1;
639 opts.fn = threeway_merge;
640 cache_tree_free(&active_cache_tree);
641 for (i = 0; i < nr_trees; i++) {
642 parse_tree(trees[i]);
643 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
644 }
645 if (unpack_trees(nr_trees, t, &opts))
646 return -1;
647 return 0;
648}
649
650static void write_tree_trivial(unsigned char *sha1)
651{
652 if (write_cache_as_tree(sha1, 0, NULL))
653 die(_("git write-tree failed to write a tree"));
654}
655
656static int try_merge_strategy(const char *strategy, struct commit_list *common,
657 struct commit_list *remoteheads,
658 struct commit *head, const char *head_arg)
659{
660 int index_fd;
661 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
662
663 index_fd = hold_locked_index(lock, 1);
664 refresh_cache(REFRESH_QUIET);
665 if (active_cache_changed &&
666 (write_cache(index_fd, active_cache, active_nr) ||
667 commit_locked_index(lock)))
668 return error(_("Unable to write index."));
669 rollback_lock_file(lock);
670
671 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
672 int clean, x;
673 struct commit *result;
674 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
675 int index_fd;
676 struct commit_list *reversed = NULL;
677 struct merge_options o;
678 struct commit_list *j;
679
680 if (remoteheads->next) {
681 error(_("Not handling anything other than two heads merge."));
682 return 2;
683 }
684
685 init_merge_options(&o);
686 if (!strcmp(strategy, "subtree"))
687 o.subtree_shift = "";
688
689 o.renormalize = option_renormalize;
690 if (verbosity < 0)
691 o.verbosity = verbosity;
692 else if (verbosity > 0)
693 o.verbosity += verbosity;
694 o.show_rename_progress =
695 show_progress == -1 ? isatty(2) : show_progress;
696
697 for (x = 0; x < xopts_nr; x++)
698 if (parse_merge_opt(&o, xopts[x]))
699 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
700
701 o.branch1 = head_arg;
702 o.branch2 = merge_remote_util(remoteheads->item)->name;
703
704 for (j = common; j; j = j->next)
705 commit_list_insert(j->item, &reversed);
706
707 index_fd = hold_locked_index(lock, 1);
708 clean = merge_recursive(&o, head,
709 remoteheads->item, reversed, &result);
710 if (active_cache_changed &&
711 (write_cache(index_fd, active_cache, active_nr) ||
712 commit_locked_index(lock)))
713 die (_("unable to write %s"), get_index_file());
714 rollback_lock_file(lock);
715 return clean ? 0 : 1;
716 } else {
717 return try_merge_command(strategy, xopts_nr, xopts,
718 common, head_arg, remoteheads);
719 }
720}
721
722static void count_diff_files(struct diff_queue_struct *q,
723 struct diff_options *opt, void *data)
724{
725 int *count = data;
726
727 (*count) += q->nr;
728}
729
730static int count_unmerged_entries(void)
731{
732 int i, ret = 0;
733
734 for (i = 0; i < active_nr; i++)
735 if (ce_stage(active_cache[i]))
736 ret++;
737
738 return ret;
739}
740
741static void split_merge_strategies(const char *string, struct strategy **list,
742 int *nr, int *alloc)
743{
744 char *p, *q, *buf;
745
746 if (!string)
747 return;
748
749 buf = xstrdup(string);
750 q = buf;
751 for (;;) {
752 p = strchr(q, ' ');
753 if (!p) {
754 ALLOC_GROW(*list, *nr + 1, *alloc);
755 (*list)[(*nr)++].name = xstrdup(q);
756 free(buf);
757 return;
758 } else {
759 *p = '\0';
760 ALLOC_GROW(*list, *nr + 1, *alloc);
761 (*list)[(*nr)++].name = xstrdup(q);
762 q = ++p;
763 }
764 }
765}
766
767static void add_strategies(const char *string, unsigned attr)
768{
769 struct strategy *list = NULL;
770 int list_alloc = 0, list_nr = 0, i;
771
772 memset(&list, 0, sizeof(list));
773 split_merge_strategies(string, &list, &list_nr, &list_alloc);
774 if (list) {
775 for (i = 0; i < list_nr; i++)
776 append_strategy(get_strategy(list[i].name));
777 return;
778 }
779 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
780 if (all_strategy[i].attr & attr)
781 append_strategy(&all_strategy[i]);
782
783}
784
785static void write_merge_msg(struct strbuf *msg)
786{
787 const char *filename = git_path("MERGE_MSG");
788 int fd = open(filename, O_WRONLY | O_CREAT, 0666);
789 if (fd < 0)
790 die_errno(_("Could not open '%s' for writing"),
791 filename);
792 if (write_in_full(fd, msg->buf, msg->len) != msg->len)
793 die_errno(_("Could not write to '%s'"), filename);
794 close(fd);
795}
796
797static void read_merge_msg(struct strbuf *msg)
798{
799 const char *filename = git_path("MERGE_MSG");
800 strbuf_reset(msg);
801 if (strbuf_read_file(msg, filename, 0) < 0)
802 die_errno(_("Could not read from '%s'"), filename);
803}
804
805static void write_merge_state(struct commit_list *);
806static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
807{
808 if (err_msg)
809 error("%s", err_msg);
810 fprintf(stderr,
811 _("Not committing merge; use 'git commit' to complete the merge.\n"));
812 write_merge_state(remoteheads);
813 exit(1);
814}
815
816static const char merge_editor_comment[] =
817N_("Please enter a commit message to explain why this merge is necessary,\n"
818 "especially if it merges an updated upstream into a topic branch.\n"
819 "\n"
820 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
821 "the commit.\n");
822
823static void prepare_to_commit(struct commit_list *remoteheads)
824{
825 struct strbuf msg = STRBUF_INIT;
826 strbuf_addbuf(&msg, &merge_msg);
827 strbuf_addch(&msg, '\n');
828 if (0 < option_edit)
829 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
830 write_merge_msg(&msg);
831 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
832 git_path("MERGE_MSG"), "merge", NULL))
833 abort_commit(remoteheads, NULL);
834 if (0 < option_edit) {
835 if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
836 abort_commit(remoteheads, NULL);
837 }
838 read_merge_msg(&msg);
839 stripspace(&msg, 0 < option_edit);
840 if (!msg.len)
841 abort_commit(remoteheads, _("Empty commit message."));
842 strbuf_release(&merge_msg);
843 strbuf_addbuf(&merge_msg, &msg);
844 strbuf_release(&msg);
845}
846
847static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
848{
849 unsigned char result_tree[20], result_commit[20];
850 struct commit_list *parent = xmalloc(sizeof(*parent));
851
852 write_tree_trivial(result_tree);
853 printf(_("Wonderful.\n"));
854 parent->item = head;
855 parent->next = xmalloc(sizeof(*parent->next));
856 parent->next->item = remoteheads->item;
857 parent->next->next = NULL;
858 prepare_to_commit(remoteheads);
859 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parent,
860 result_commit, NULL, sign_commit))
861 die(_("failed to write commit object"));
862 finish(head, remoteheads, result_commit, "In-index merge");
863 drop_save();
864 return 0;
865}
866
867static int finish_automerge(struct commit *head,
868 int head_subsumed,
869 struct commit_list *common,
870 struct commit_list *remoteheads,
871 unsigned char *result_tree,
872 const char *wt_strategy)
873{
874 struct commit_list *parents = NULL;
875 struct strbuf buf = STRBUF_INIT;
876 unsigned char result_commit[20];
877
878 free_commit_list(common);
879 parents = remoteheads;
880 if (!head_subsumed || fast_forward == FF_NO)
881 commit_list_insert(head, &parents);
882 strbuf_addch(&merge_msg, '\n');
883 prepare_to_commit(remoteheads);
884 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
885 result_commit, NULL, sign_commit))
886 die(_("failed to write commit object"));
887 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
888 finish(head, remoteheads, result_commit, buf.buf);
889 strbuf_release(&buf);
890 drop_save();
891 return 0;
892}
893
894static int suggest_conflicts(int renormalizing)
895{
896 const char *filename;
897 FILE *fp;
898 int pos;
899
900 filename = git_path("MERGE_MSG");
901 fp = fopen(filename, "a");
902 if (!fp)
903 die_errno(_("Could not open '%s' for writing"), filename);
904 fprintf(fp, "\nConflicts:\n");
905 for (pos = 0; pos < active_nr; pos++) {
906 const struct cache_entry *ce = active_cache[pos];
907
908 if (ce_stage(ce)) {
909 fprintf(fp, "\t%s\n", ce->name);
910 while (pos + 1 < active_nr &&
911 !strcmp(ce->name,
912 active_cache[pos + 1]->name))
913 pos++;
914 }
915 }
916 fclose(fp);
917 rerere(allow_rerere_auto);
918 printf(_("Automatic merge failed; "
919 "fix conflicts and then commit the result.\n"));
920 return 1;
921}
922
923static struct commit *is_old_style_invocation(int argc, const char **argv,
924 const unsigned char *head)
925{
926 struct commit *second_token = NULL;
927 if (argc > 2) {
928 unsigned char second_sha1[20];
929
930 if (get_sha1(argv[1], second_sha1))
931 return NULL;
932 second_token = lookup_commit_reference_gently(second_sha1, 0);
933 if (!second_token)
934 die(_("'%s' is not a commit"), argv[1]);
935 if (hashcmp(second_token->object.sha1, head))
936 return NULL;
937 }
938 return second_token;
939}
940
941static int evaluate_result(void)
942{
943 int cnt = 0;
944 struct rev_info rev;
945
946 /* Check how many files differ. */
947 init_revisions(&rev, "");
948 setup_revisions(0, NULL, &rev, NULL);
949 rev.diffopt.output_format |=
950 DIFF_FORMAT_CALLBACK;
951 rev.diffopt.format_callback = count_diff_files;
952 rev.diffopt.format_callback_data = &cnt;
953 run_diff_files(&rev, 0);
954
955 /*
956 * Check how many unmerged entries are
957 * there.
958 */
959 cnt += count_unmerged_entries();
960
961 return cnt;
962}
963
964/*
965 * Pretend as if the user told us to merge with the remote-tracking
966 * branch we have for the upstream of the current branch
967 */
968static int setup_with_upstream(const char ***argv)
969{
970 struct branch *branch = branch_get(NULL);
971 int i;
972 const char **args;
973
974 if (!branch)
975 die(_("No current branch."));
976 if (!branch->remote)
977 die(_("No remote for the current branch."));
978 if (!branch->merge_nr)
979 die(_("No default upstream defined for the current branch."));
980
981 args = xcalloc(branch->merge_nr + 1, sizeof(char *));
982 for (i = 0; i < branch->merge_nr; i++) {
983 if (!branch->merge[i]->dst)
984 die(_("No remote-tracking branch for %s from %s"),
985 branch->merge[i]->src, branch->remote_name);
986 args[i] = branch->merge[i]->dst;
987 }
988 args[i] = NULL;
989 *argv = args;
990 return i;
991}
992
993static void write_merge_state(struct commit_list *remoteheads)
994{
995 const char *filename;
996 int fd;
997 struct commit_list *j;
998 struct strbuf buf = STRBUF_INIT;
999
1000 for (j = remoteheads; j; j = j->next) {
1001 unsigned const char *sha1;
1002 struct commit *c = j->item;
1003 if (c->util && merge_remote_util(c)->obj) {
1004 sha1 = merge_remote_util(c)->obj->sha1;
1005 } else {
1006 sha1 = c->object.sha1;
1007 }
1008 strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
1009 }
1010 filename = git_path("MERGE_HEAD");
1011 fd = open(filename, O_WRONLY | O_CREAT, 0666);
1012 if (fd < 0)
1013 die_errno(_("Could not open '%s' for writing"), filename);
1014 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1015 die_errno(_("Could not write to '%s'"), filename);
1016 close(fd);
1017 strbuf_addch(&merge_msg, '\n');
1018 write_merge_msg(&merge_msg);
1019
1020 filename = git_path("MERGE_MODE");
1021 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
1022 if (fd < 0)
1023 die_errno(_("Could not open '%s' for writing"), filename);
1024 strbuf_reset(&buf);
1025 if (fast_forward == FF_NO)
1026 strbuf_addf(&buf, "no-ff");
1027 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1028 die_errno(_("Could not write to '%s'"), filename);
1029 close(fd);
1030}
1031
1032static int default_edit_option(void)
1033{
1034 static const char name[] = "GIT_MERGE_AUTOEDIT";
1035 const char *e = getenv(name);
1036 struct stat st_stdin, st_stdout;
1037
1038 if (have_message)
1039 /* an explicit -m msg without --[no-]edit */
1040 return 0;
1041
1042 if (e) {
1043 int v = git_config_maybe_bool(name, e);
1044 if (v < 0)
1045 die("Bad value '%s' in environment '%s'", e, name);
1046 return v;
1047 }
1048
1049 /* Use editor if stdin and stdout are the same and is a tty */
1050 return (!fstat(0, &st_stdin) &&
1051 !fstat(1, &st_stdout) &&
1052 isatty(0) && isatty(1) &&
1053 st_stdin.st_dev == st_stdout.st_dev &&
1054 st_stdin.st_ino == st_stdout.st_ino &&
1055 st_stdin.st_mode == st_stdout.st_mode);
1056}
1057
1058static struct commit_list *collect_parents(struct commit *head_commit,
1059 int *head_subsumed,
1060 int argc, const char **argv)
1061{
1062 int i;
1063 struct commit_list *remoteheads = NULL, *parents, *next;
1064 struct commit_list **remotes = &remoteheads;
1065
1066 if (head_commit)
1067 remotes = &commit_list_insert(head_commit, remotes)->next;
1068 for (i = 0; i < argc; i++) {
1069 struct commit *commit = get_merge_parent(argv[i]);
1070 if (!commit)
1071 help_unknown_ref(argv[i], "merge",
1072 "not something we can merge");
1073 remotes = &commit_list_insert(commit, remotes)->next;
1074 }
1075 *remotes = NULL;
1076
1077 parents = reduce_heads(remoteheads);
1078
1079 *head_subsumed = 1; /* we will flip this to 0 when we find it */
1080 for (remoteheads = NULL, remotes = &remoteheads;
1081 parents;
1082 parents = next) {
1083 struct commit *commit = parents->item;
1084 next = parents->next;
1085 if (commit == head_commit)
1086 *head_subsumed = 0;
1087 else
1088 remotes = &commit_list_insert(commit, remotes)->next;
1089 }
1090 return remoteheads;
1091}
1092
1093int cmd_merge(int argc, const char **argv, const char *prefix)
1094{
1095 unsigned char result_tree[20];
1096 unsigned char stash[20];
1097 unsigned char head_sha1[20];
1098 struct commit *head_commit;
1099 struct strbuf buf = STRBUF_INIT;
1100 const char *head_arg;
1101 int flag, i, ret = 0, head_subsumed;
1102 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1103 struct commit_list *common = NULL;
1104 const char *best_strategy = NULL, *wt_strategy = NULL;
1105 struct commit_list *remoteheads, *p;
1106 void *branch_to_free;
1107
1108 if (argc == 2 && !strcmp(argv[1], "-h"))
1109 usage_with_options(builtin_merge_usage, builtin_merge_options);
1110
1111 /*
1112 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1113 * current branch.
1114 */
1115 branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
1116 if (branch && starts_with(branch, "refs/heads/"))
1117 branch += 11;
1118 if (!branch || is_null_sha1(head_sha1))
1119 head_commit = NULL;
1120 else
1121 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1122
1123 git_config(git_merge_config, NULL);
1124
1125 if (branch_mergeoptions)
1126 parse_branch_merge_options(branch_mergeoptions);
1127 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1128 builtin_merge_usage, 0);
1129 if (shortlog_len < 0)
1130 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1131
1132 if (verbosity < 0 && show_progress == -1)
1133 show_progress = 0;
1134
1135 if (abort_current_merge) {
1136 int nargc = 2;
1137 const char *nargv[] = {"reset", "--merge", NULL};
1138
1139 if (!file_exists(git_path("MERGE_HEAD")))
1140 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1141
1142 /* Invoke 'git reset --merge' */
1143 ret = cmd_reset(nargc, nargv, prefix);
1144 goto done;
1145 }
1146
1147 if (read_cache_unmerged())
1148 die_resolve_conflict("merge");
1149
1150 if (file_exists(git_path("MERGE_HEAD"))) {
1151 /*
1152 * There is no unmerged entry, don't advise 'git
1153 * add/rm <file>', just 'git commit'.
1154 */
1155 if (advice_resolve_conflict)
1156 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1157 "Please, commit your changes before you can merge."));
1158 else
1159 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1160 }
1161 if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
1162 if (advice_resolve_conflict)
1163 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1164 "Please, commit your changes before you can merge."));
1165 else
1166 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1167 }
1168 resolve_undo_clear();
1169
1170 if (verbosity < 0)
1171 show_diffstat = 0;
1172
1173 if (squash) {
1174 if (fast_forward == FF_NO)
1175 die(_("You cannot combine --squash with --no-ff."));
1176 option_commit = 0;
1177 }
1178
1179 if (!abort_current_merge) {
1180 if (!argc) {
1181 if (default_to_upstream)
1182 argc = setup_with_upstream(&argv);
1183 else
1184 die(_("No commit specified and merge.defaultToUpstream not set."));
1185 } else if (argc == 1 && !strcmp(argv[0], "-"))
1186 argv[0] = "@{-1}";
1187 }
1188 if (!argc)
1189 usage_with_options(builtin_merge_usage,
1190 builtin_merge_options);
1191
1192 /*
1193 * This could be traditional "merge <msg> HEAD <commit>..." and
1194 * the way we can tell it is to see if the second token is HEAD,
1195 * but some people might have misused the interface and used a
1196 * commit-ish that is the same as HEAD there instead.
1197 * Traditional format never would have "-m" so it is an
1198 * additional safety measure to check for it.
1199 */
1200
1201 if (!have_message && head_commit &&
1202 is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
1203 strbuf_addstr(&merge_msg, argv[0]);
1204 head_arg = argv[1];
1205 argv += 2;
1206 argc -= 2;
1207 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1208 } else if (!head_commit) {
1209 struct commit *remote_head;
1210 /*
1211 * If the merged head is a valid one there is no reason
1212 * to forbid "git merge" into a branch yet to be born.
1213 * We do the same for "git pull".
1214 */
1215 if (argc != 1)
1216 die(_("Can merge only exactly one commit into "
1217 "empty head"));
1218 if (squash)
1219 die(_("Squash commit into empty head not supported yet"));
1220 if (fast_forward == FF_NO)
1221 die(_("Non-fast-forward commit does not make sense into "
1222 "an empty head"));
1223 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1224 remote_head = remoteheads->item;
1225 if (!remote_head)
1226 die(_("%s - not something we can merge"), argv[0]);
1227 read_empty(remote_head->object.sha1, 0);
1228 update_ref("initial pull", "HEAD", remote_head->object.sha1,
1229 NULL, 0, DIE_ON_ERR);
1230 goto done;
1231 } else {
1232 struct strbuf merge_names = STRBUF_INIT;
1233
1234 /* We are invoked directly as the first-class UI. */
1235 head_arg = "HEAD";
1236
1237 /*
1238 * All the rest are the commits being merged; prepare
1239 * the standard merge summary message to be appended
1240 * to the given message.
1241 */
1242 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1243 for (p = remoteheads; p; p = p->next)
1244 merge_name(merge_remote_util(p->item)->name, &merge_names);
1245
1246 if (!have_message || shortlog_len) {
1247 struct fmt_merge_msg_opts opts;
1248 memset(&opts, 0, sizeof(opts));
1249 opts.add_title = !have_message;
1250 opts.shortlog_len = shortlog_len;
1251 opts.credit_people = (0 < option_edit);
1252
1253 fmt_merge_msg(&merge_names, &merge_msg, &opts);
1254 if (merge_msg.len)
1255 strbuf_setlen(&merge_msg, merge_msg.len - 1);
1256 }
1257 }
1258
1259 if (!head_commit || !argc)
1260 usage_with_options(builtin_merge_usage,
1261 builtin_merge_options);
1262
1263 if (verify_signatures) {
1264 for (p = remoteheads; p; p = p->next) {
1265 struct commit *commit = p->item;
1266 char hex[41];
1267 struct signature_check signature_check;
1268 memset(&signature_check, 0, sizeof(signature_check));
1269
1270 check_commit_signature(commit, &signature_check);
1271
1272 strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
1273 switch (signature_check.result) {
1274 case 'G':
1275 break;
1276 case 'U':
1277 die(_("Commit %s has an untrusted GPG signature, "
1278 "allegedly by %s."), hex, signature_check.signer);
1279 case 'B':
1280 die(_("Commit %s has a bad GPG signature "
1281 "allegedly by %s."), hex, signature_check.signer);
1282 default: /* 'N' */
1283 die(_("Commit %s does not have a GPG signature."), hex);
1284 }
1285 if (verbosity >= 0 && signature_check.result == 'G')
1286 printf(_("Commit %s has a good GPG signature by %s\n"),
1287 hex, signature_check.signer);
1288
1289 free(signature_check.gpg_output);
1290 free(signature_check.gpg_status);
1291 free(signature_check.signer);
1292 free(signature_check.key);
1293 }
1294 }
1295
1296 strbuf_addstr(&buf, "merge");
1297 for (p = remoteheads; p; p = p->next)
1298 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1299 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1300 strbuf_reset(&buf);
1301
1302 for (p = remoteheads; p; p = p->next) {
1303 struct commit *commit = p->item;
1304 strbuf_addf(&buf, "GITHEAD_%s",
1305 sha1_to_hex(commit->object.sha1));
1306 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1307 strbuf_reset(&buf);
1308 if (fast_forward != FF_ONLY &&
1309 merge_remote_util(commit) &&
1310 merge_remote_util(commit)->obj &&
1311 merge_remote_util(commit)->obj->type == OBJ_TAG)
1312 fast_forward = FF_NO;
1313 }
1314
1315 if (option_edit < 0)
1316 option_edit = default_edit_option();
1317
1318 if (!use_strategies) {
1319 if (!remoteheads)
1320 ; /* already up-to-date */
1321 else if (!remoteheads->next)
1322 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1323 else
1324 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1325 }
1326
1327 for (i = 0; i < use_strategies_nr; i++) {
1328 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1329 fast_forward = FF_NO;
1330 if (use_strategies[i]->attr & NO_TRIVIAL)
1331 allow_trivial = 0;
1332 }
1333
1334 if (!remoteheads)
1335 ; /* already up-to-date */
1336 else if (!remoteheads->next)
1337 common = get_merge_bases(head_commit, remoteheads->item, 1);
1338 else {
1339 struct commit_list *list = remoteheads;
1340 commit_list_insert(head_commit, &list);
1341 common = get_octopus_merge_bases(list);
1342 free(list);
1343 }
1344
1345 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
1346 NULL, 0, DIE_ON_ERR);
1347
1348 if (remoteheads && !common)
1349 ; /* No common ancestors found. We need a real merge. */
1350 else if (!remoteheads ||
1351 (!remoteheads->next && !common->next &&
1352 common->item == remoteheads->item)) {
1353 /*
1354 * If head can reach all the merge then we are up to date.
1355 * but first the most common case of merging one remote.
1356 */
1357 finish_up_to_date("Already up-to-date.");
1358 goto done;
1359 } else if (fast_forward != FF_NO && !remoteheads->next &&
1360 !common->next &&
1361 !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
1362 /* Again the most common case of merging one remote. */
1363 struct strbuf msg = STRBUF_INIT;
1364 struct commit *commit;
1365 char hex[41];
1366
1367 strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
1368
1369 if (verbosity >= 0)
1370 printf(_("Updating %s..%s\n"),
1371 hex,
1372 find_unique_abbrev(remoteheads->item->object.sha1,
1373 DEFAULT_ABBREV));
1374 strbuf_addstr(&msg, "Fast-forward");
1375 if (have_message)
1376 strbuf_addstr(&msg,
1377 " (no commit created; -m option ignored)");
1378 commit = remoteheads->item;
1379 if (!commit) {
1380 ret = 1;
1381 goto done;
1382 }
1383
1384 if (checkout_fast_forward(head_commit->object.sha1,
1385 commit->object.sha1,
1386 overwrite_ignore)) {
1387 ret = 1;
1388 goto done;
1389 }
1390
1391 finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
1392 drop_save();
1393 goto done;
1394 } else if (!remoteheads->next && common->next)
1395 ;
1396 /*
1397 * We are not doing octopus and not fast-forward. Need
1398 * a real merge.
1399 */
1400 else if (!remoteheads->next && !common->next && option_commit) {
1401 /*
1402 * We are not doing octopus, not fast-forward, and have
1403 * only one common.
1404 */
1405 refresh_cache(REFRESH_QUIET);
1406 if (allow_trivial && fast_forward != FF_ONLY) {
1407 /* See if it is really trivial. */
1408 git_committer_info(IDENT_STRICT);
1409 printf(_("Trying really trivial in-index merge...\n"));
1410 if (!read_tree_trivial(common->item->object.sha1,
1411 head_commit->object.sha1,
1412 remoteheads->item->object.sha1)) {
1413 ret = merge_trivial(head_commit, remoteheads);
1414 goto done;
1415 }
1416 printf(_("Nope.\n"));
1417 }
1418 } else {
1419 /*
1420 * An octopus. If we can reach all the remote we are up
1421 * to date.
1422 */
1423 int up_to_date = 1;
1424 struct commit_list *j;
1425
1426 for (j = remoteheads; j; j = j->next) {
1427 struct commit_list *common_one;
1428
1429 /*
1430 * Here we *have* to calculate the individual
1431 * merge_bases again, otherwise "git merge HEAD^
1432 * HEAD^^" would be missed.
1433 */
1434 common_one = get_merge_bases(head_commit, j->item, 1);
1435 if (hashcmp(common_one->item->object.sha1,
1436 j->item->object.sha1)) {
1437 up_to_date = 0;
1438 break;
1439 }
1440 }
1441 if (up_to_date) {
1442 finish_up_to_date("Already up-to-date. Yeeah!");
1443 goto done;
1444 }
1445 }
1446
1447 if (fast_forward == FF_ONLY)
1448 die(_("Not possible to fast-forward, aborting."));
1449
1450 /* We are going to make a new commit. */
1451 git_committer_info(IDENT_STRICT);
1452
1453 /*
1454 * At this point, we need a real merge. No matter what strategy
1455 * we use, it would operate on the index, possibly affecting the
1456 * working tree, and when resolved cleanly, have the desired
1457 * tree in the index -- this means that the index must be in
1458 * sync with the head commit. The strategies are responsible
1459 * to ensure this.
1460 */
1461 if (use_strategies_nr == 1 ||
1462 /*
1463 * Stash away the local changes so that we can try more than one.
1464 */
1465 save_state(stash))
1466 hashcpy(stash, null_sha1);
1467
1468 for (i = 0; i < use_strategies_nr; i++) {
1469 int ret;
1470 if (i) {
1471 printf(_("Rewinding the tree to pristine...\n"));
1472 restore_state(head_commit->object.sha1, stash);
1473 }
1474 if (use_strategies_nr != 1)
1475 printf(_("Trying merge strategy %s...\n"),
1476 use_strategies[i]->name);
1477 /*
1478 * Remember which strategy left the state in the working
1479 * tree.
1480 */
1481 wt_strategy = use_strategies[i]->name;
1482
1483 ret = try_merge_strategy(use_strategies[i]->name,
1484 common, remoteheads,
1485 head_commit, head_arg);
1486 if (!option_commit && !ret) {
1487 merge_was_ok = 1;
1488 /*
1489 * This is necessary here just to avoid writing
1490 * the tree, but later we will *not* exit with
1491 * status code 1 because merge_was_ok is set.
1492 */
1493 ret = 1;
1494 }
1495
1496 if (ret) {
1497 /*
1498 * The backend exits with 1 when conflicts are
1499 * left to be resolved, with 2 when it does not
1500 * handle the given merge at all.
1501 */
1502 if (ret == 1) {
1503 int cnt = evaluate_result();
1504
1505 if (best_cnt <= 0 || cnt <= best_cnt) {
1506 best_strategy = use_strategies[i]->name;
1507 best_cnt = cnt;
1508 }
1509 }
1510 if (merge_was_ok)
1511 break;
1512 else
1513 continue;
1514 }
1515
1516 /* Automerge succeeded. */
1517 write_tree_trivial(result_tree);
1518 automerge_was_ok = 1;
1519 break;
1520 }
1521
1522 /*
1523 * If we have a resulting tree, that means the strategy module
1524 * auto resolved the merge cleanly.
1525 */
1526 if (automerge_was_ok) {
1527 ret = finish_automerge(head_commit, head_subsumed,
1528 common, remoteheads,
1529 result_tree, wt_strategy);
1530 goto done;
1531 }
1532
1533 /*
1534 * Pick the result from the best strategy and have the user fix
1535 * it up.
1536 */
1537 if (!best_strategy) {
1538 restore_state(head_commit->object.sha1, stash);
1539 if (use_strategies_nr > 1)
1540 fprintf(stderr,
1541 _("No merge strategy handled the merge.\n"));
1542 else
1543 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1544 use_strategies[0]->name);
1545 ret = 2;
1546 goto done;
1547 } else if (best_strategy == wt_strategy)
1548 ; /* We already have its result in the working tree. */
1549 else {
1550 printf(_("Rewinding the tree to pristine...\n"));
1551 restore_state(head_commit->object.sha1, stash);
1552 printf(_("Using the %s to prepare resolving by hand.\n"),
1553 best_strategy);
1554 try_merge_strategy(best_strategy, common, remoteheads,
1555 head_commit, head_arg);
1556 }
1557
1558 if (squash)
1559 finish(head_commit, remoteheads, NULL, NULL);
1560 else
1561 write_merge_state(remoteheads);
1562
1563 if (merge_was_ok)
1564 fprintf(stderr, _("Automatic merge went well; "
1565 "stopped before committing as requested\n"));
1566 else
1567 ret = suggest_conflicts(option_renormalize);
1568
1569done:
1570 free(branch_to_free);
1571 return ret;
1572}