Merge branch 'jt/packmigrate'
[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 "config.h"
11 #include "parse-options.h"
12 #include "builtin.h"
13 #include "lockfile.h"
14 #include "run-command.h"
15 #include "diff.h"
16 #include "refs.h"
17 #include "commit.h"
18 #include "diffcore.h"
19 #include "revision.h"
20 #include "unpack-trees.h"
21 #include "cache-tree.h"
22 #include "dir.h"
23 #include "utf8.h"
24 #include "log-tree.h"
25 #include "color.h"
26 #include "rerere.h"
27 #include "help.h"
28 #include "merge-recursive.h"
29 #include "resolve-undo.h"
30 #include "remote.h"
31 #include "fmt-merge-msg.h"
32 #include "gpg-interface.h"
33 #include "sequencer.h"
34 #include "string-list.h"
35 #include "packfile.h"
36
37 #define DEFAULT_TWOHEAD (1<<0)
38 #define DEFAULT_OCTOPUS (1<<1)
39 #define NO_FAST_FORWARD (1<<2)
40 #define NO_TRIVIAL (1<<3)
41
42 struct strategy {
43 const char *name;
44 unsigned attr;
45 };
46
47 static const char * const builtin_merge_usage[] = {
48 N_("git merge [<options>] [<commit>...]"),
49 N_("git merge --abort"),
50 N_("git merge --continue"),
51 NULL
52 };
53
54 static int show_diffstat = 1, shortlog_len = -1, squash;
55 static int option_commit = 1;
56 static int option_edit = -1;
57 static int allow_trivial = 1, have_message, verify_signatures;
58 static int overwrite_ignore = 1;
59 static struct strbuf merge_msg = STRBUF_INIT;
60 static struct strategy **use_strategies;
61 static size_t use_strategies_nr, use_strategies_alloc;
62 static const char **xopts;
63 static size_t xopts_nr, xopts_alloc;
64 static const char *branch;
65 static char *branch_mergeoptions;
66 static int option_renormalize;
67 static int verbosity;
68 static int allow_rerere_auto;
69 static int abort_current_merge;
70 static int continue_current_merge;
71 static int allow_unrelated_histories;
72 static int show_progress = -1;
73 static int default_to_upstream = 1;
74 static int signoff;
75 static const char *sign_commit;
76
77 static struct strategy all_strategy[] = {
78 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
79 { "octopus", DEFAULT_OCTOPUS },
80 { "resolve", 0 },
81 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
82 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
83 };
84
85 static const char *pull_twohead, *pull_octopus;
86
87 enum ff_type {
88 FF_NO,
89 FF_ALLOW,
90 FF_ONLY
91 };
92
93 static enum ff_type fast_forward = FF_ALLOW;
94
95 static int option_parse_message(const struct option *opt,
96 const char *arg, int unset)
97 {
98 struct strbuf *buf = opt->value;
99
100 if (unset)
101 strbuf_setlen(buf, 0);
102 else if (arg) {
103 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
104 have_message = 1;
105 } else
106 return error(_("switch `m' requires a value"));
107 return 0;
108 }
109
110 static struct strategy *get_strategy(const char *name)
111 {
112 int i;
113 struct strategy *ret;
114 static struct cmdnames main_cmds, other_cmds;
115 static int loaded;
116
117 if (!name)
118 return NULL;
119
120 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
121 if (!strcmp(name, all_strategy[i].name))
122 return &all_strategy[i];
123
124 if (!loaded) {
125 struct cmdnames not_strategies;
126 loaded = 1;
127
128 memset(&not_strategies, 0, sizeof(struct cmdnames));
129 load_command_list("git-merge-", &main_cmds, &other_cmds);
130 for (i = 0; i < main_cmds.cnt; i++) {
131 int j, found = 0;
132 struct cmdname *ent = main_cmds.names[i];
133 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
134 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
135 && !all_strategy[j].name[ent->len])
136 found = 1;
137 if (!found)
138 add_cmdname(&not_strategies, ent->name, ent->len);
139 }
140 exclude_cmds(&main_cmds, &not_strategies);
141 }
142 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
143 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
144 fprintf(stderr, _("Available strategies are:"));
145 for (i = 0; i < main_cmds.cnt; i++)
146 fprintf(stderr, " %s", main_cmds.names[i]->name);
147 fprintf(stderr, ".\n");
148 if (other_cmds.cnt) {
149 fprintf(stderr, _("Available custom strategies are:"));
150 for (i = 0; i < other_cmds.cnt; i++)
151 fprintf(stderr, " %s", other_cmds.names[i]->name);
152 fprintf(stderr, ".\n");
153 }
154 exit(1);
155 }
156
157 ret = xcalloc(1, sizeof(struct strategy));
158 ret->name = xstrdup(name);
159 ret->attr = NO_TRIVIAL;
160 return ret;
161 }
162
163 static void append_strategy(struct strategy *s)
164 {
165 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
166 use_strategies[use_strategies_nr++] = s;
167 }
168
169 static int option_parse_strategy(const struct option *opt,
170 const char *name, int unset)
171 {
172 if (unset)
173 return 0;
174
175 append_strategy(get_strategy(name));
176 return 0;
177 }
178
179 static int option_parse_x(const struct option *opt,
180 const char *arg, int unset)
181 {
182 if (unset)
183 return 0;
184
185 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
186 xopts[xopts_nr++] = xstrdup(arg);
187 return 0;
188 }
189
190 static int option_parse_n(const struct option *opt,
191 const char *arg, int unset)
192 {
193 show_diffstat = unset;
194 return 0;
195 }
196
197 static struct option builtin_merge_options[] = {
198 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
199 N_("do not show a diffstat at the end of the merge"),
200 PARSE_OPT_NOARG, option_parse_n },
201 OPT_BOOL(0, "stat", &show_diffstat,
202 N_("show a diffstat at the end of the merge")),
203 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
204 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
205 N_("add (at most <n>) entries from shortlog to merge commit message"),
206 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
207 OPT_BOOL(0, "squash", &squash,
208 N_("create a single commit instead of doing a merge")),
209 OPT_BOOL(0, "commit", &option_commit,
210 N_("perform a commit if the merge succeeds (default)")),
211 OPT_BOOL('e', "edit", &option_edit,
212 N_("edit message before committing")),
213 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
214 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
215 N_("abort if fast-forward is not possible"),
216 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
217 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
218 OPT_BOOL(0, "verify-signatures", &verify_signatures,
219 N_("verify that the named commit has a valid GPG signature")),
220 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
221 N_("merge strategy to use"), option_parse_strategy),
222 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
223 N_("option for selected merge strategy"), option_parse_x),
224 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
225 N_("merge commit message (for a non-fast-forward merge)"),
226 option_parse_message),
227 OPT__VERBOSITY(&verbosity),
228 OPT_BOOL(0, "abort", &abort_current_merge,
229 N_("abort the current in-progress merge")),
230 OPT_BOOL(0, "continue", &continue_current_merge,
231 N_("continue the current in-progress merge")),
232 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
233 N_("allow merging unrelated histories")),
234 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
235 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
236 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
237 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
238 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
239 OPT_END()
240 };
241
242 /* Cleans up metadata that is uninteresting after a succeeded merge. */
243 static void drop_save(void)
244 {
245 unlink(git_path_merge_head());
246 unlink(git_path_merge_msg());
247 unlink(git_path_merge_mode());
248 }
249
250 static int save_state(struct object_id *stash)
251 {
252 int len;
253 struct child_process cp = CHILD_PROCESS_INIT;
254 struct strbuf buffer = STRBUF_INIT;
255 const char *argv[] = {"stash", "create", NULL};
256
257 cp.argv = argv;
258 cp.out = -1;
259 cp.git_cmd = 1;
260
261 if (start_command(&cp))
262 die(_("could not run stash."));
263 len = strbuf_read(&buffer, cp.out, 1024);
264 close(cp.out);
265
266 if (finish_command(&cp) || len < 0)
267 die(_("stash failed"));
268 else if (!len) /* no changes */
269 return -1;
270 strbuf_setlen(&buffer, buffer.len-1);
271 if (get_oid(buffer.buf, stash))
272 die(_("not a valid object: %s"), buffer.buf);
273 return 0;
274 }
275
276 static void read_empty(unsigned const char *sha1, int verbose)
277 {
278 int i = 0;
279 const char *args[7];
280
281 args[i++] = "read-tree";
282 if (verbose)
283 args[i++] = "-v";
284 args[i++] = "-m";
285 args[i++] = "-u";
286 args[i++] = EMPTY_TREE_SHA1_HEX;
287 args[i++] = sha1_to_hex(sha1);
288 args[i] = NULL;
289
290 if (run_command_v_opt(args, RUN_GIT_CMD))
291 die(_("read-tree failed"));
292 }
293
294 static void reset_hard(unsigned const char *sha1, int verbose)
295 {
296 int i = 0;
297 const char *args[6];
298
299 args[i++] = "read-tree";
300 if (verbose)
301 args[i++] = "-v";
302 args[i++] = "--reset";
303 args[i++] = "-u";
304 args[i++] = sha1_to_hex(sha1);
305 args[i] = NULL;
306
307 if (run_command_v_opt(args, RUN_GIT_CMD))
308 die(_("read-tree failed"));
309 }
310
311 static void restore_state(const struct object_id *head,
312 const struct object_id *stash)
313 {
314 struct strbuf sb = STRBUF_INIT;
315 const char *args[] = { "stash", "apply", NULL, NULL };
316
317 if (is_null_oid(stash))
318 return;
319
320 reset_hard(head->hash, 1);
321
322 args[2] = oid_to_hex(stash);
323
324 /*
325 * It is OK to ignore error here, for example when there was
326 * nothing to restore.
327 */
328 run_command_v_opt(args, RUN_GIT_CMD);
329
330 strbuf_release(&sb);
331 refresh_cache(REFRESH_QUIET);
332 }
333
334 /* This is called when no merge was necessary. */
335 static void finish_up_to_date(const char *msg)
336 {
337 if (verbosity >= 0)
338 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
339 drop_save();
340 }
341
342 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
343 {
344 struct rev_info rev;
345 struct strbuf out = STRBUF_INIT;
346 struct commit_list *j;
347 struct pretty_print_context ctx = {0};
348
349 printf(_("Squash commit -- not updating HEAD\n"));
350
351 init_revisions(&rev, NULL);
352 rev.ignore_merges = 1;
353 rev.commit_format = CMIT_FMT_MEDIUM;
354
355 commit->object.flags |= UNINTERESTING;
356 add_pending_object(&rev, &commit->object, NULL);
357
358 for (j = remoteheads; j; j = j->next)
359 add_pending_object(&rev, &j->item->object, NULL);
360
361 setup_revisions(0, NULL, &rev, NULL);
362 if (prepare_revision_walk(&rev))
363 die(_("revision walk setup failed"));
364
365 ctx.abbrev = rev.abbrev;
366 ctx.date_mode = rev.date_mode;
367 ctx.fmt = rev.commit_format;
368
369 strbuf_addstr(&out, "Squashed commit of the following:\n");
370 while ((commit = get_revision(&rev)) != NULL) {
371 strbuf_addch(&out, '\n');
372 strbuf_addf(&out, "commit %s\n",
373 oid_to_hex(&commit->object.oid));
374 pretty_print_commit(&ctx, commit, &out);
375 }
376 write_file_buf(git_path_squash_msg(), out.buf, out.len);
377 strbuf_release(&out);
378 }
379
380 static void finish(struct commit *head_commit,
381 struct commit_list *remoteheads,
382 const struct object_id *new_head, const char *msg)
383 {
384 struct strbuf reflog_message = STRBUF_INIT;
385 const struct object_id *head = &head_commit->object.oid;
386
387 if (!msg)
388 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
389 else {
390 if (verbosity >= 0)
391 printf("%s\n", msg);
392 strbuf_addf(&reflog_message, "%s: %s",
393 getenv("GIT_REFLOG_ACTION"), msg);
394 }
395 if (squash) {
396 squash_message(head_commit, remoteheads);
397 } else {
398 if (verbosity >= 0 && !merge_msg.len)
399 printf(_("No merge message -- not updating HEAD\n"));
400 else {
401 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
402 update_ref(reflog_message.buf, "HEAD",
403 new_head->hash, head->hash, 0,
404 UPDATE_REFS_DIE_ON_ERR);
405 /*
406 * We ignore errors in 'gc --auto', since the
407 * user should see them.
408 */
409 close_all_packs();
410 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
411 }
412 }
413 if (new_head && show_diffstat) {
414 struct diff_options opts;
415 diff_setup(&opts);
416 opts.stat_width = -1; /* use full terminal width */
417 opts.stat_graph_width = -1; /* respect statGraphWidth config */
418 opts.output_format |=
419 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
420 opts.detect_rename = DIFF_DETECT_RENAME;
421 diff_setup_done(&opts);
422 diff_tree_oid(head, new_head, "", &opts);
423 diffcore_std(&opts);
424 diff_flush(&opts);
425 }
426
427 /* Run a post-merge hook */
428 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
429
430 strbuf_release(&reflog_message);
431 }
432
433 /* Get the name for the merge commit's message. */
434 static void merge_name(const char *remote, struct strbuf *msg)
435 {
436 struct commit *remote_head;
437 struct object_id branch_head;
438 struct strbuf buf = STRBUF_INIT;
439 struct strbuf bname = STRBUF_INIT;
440 const char *ptr;
441 char *found_ref;
442 int len, early;
443
444 strbuf_branchname(&bname, remote, 0);
445 remote = bname.buf;
446
447 oidclr(&branch_head);
448 remote_head = get_merge_parent(remote);
449 if (!remote_head)
450 die(_("'%s' does not point to a commit"), remote);
451
452 if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
453 if (starts_with(found_ref, "refs/heads/")) {
454 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
455 oid_to_hex(&branch_head), remote);
456 goto cleanup;
457 }
458 if (starts_with(found_ref, "refs/tags/")) {
459 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
460 oid_to_hex(&branch_head), remote);
461 goto cleanup;
462 }
463 if (starts_with(found_ref, "refs/remotes/")) {
464 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
465 oid_to_hex(&branch_head), remote);
466 goto cleanup;
467 }
468 }
469
470 /* See if remote matches <name>^^^.. or <name>~<number> */
471 for (len = 0, ptr = remote + strlen(remote);
472 remote < ptr && ptr[-1] == '^';
473 ptr--)
474 len++;
475 if (len)
476 early = 1;
477 else {
478 early = 0;
479 ptr = strrchr(remote, '~');
480 if (ptr) {
481 int seen_nonzero = 0;
482
483 len++; /* count ~ */
484 while (*++ptr && isdigit(*ptr)) {
485 seen_nonzero |= (*ptr != '0');
486 len++;
487 }
488 if (*ptr)
489 len = 0; /* not ...~<number> */
490 else if (seen_nonzero)
491 early = 1;
492 else if (len == 1)
493 early = 1; /* "name~" is "name~1"! */
494 }
495 }
496 if (len) {
497 struct strbuf truname = STRBUF_INIT;
498 strbuf_addf(&truname, "refs/heads/%s", remote);
499 strbuf_setlen(&truname, truname.len - len);
500 if (ref_exists(truname.buf)) {
501 strbuf_addf(msg,
502 "%s\t\tbranch '%s'%s of .\n",
503 oid_to_hex(&remote_head->object.oid),
504 truname.buf + 11,
505 (early ? " (early part)" : ""));
506 strbuf_release(&truname);
507 goto cleanup;
508 }
509 strbuf_release(&truname);
510 }
511
512 if (remote_head->util) {
513 struct merge_remote_desc *desc;
514 desc = merge_remote_util(remote_head);
515 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
516 strbuf_addf(msg, "%s\t\t%s '%s'\n",
517 oid_to_hex(&desc->obj->oid),
518 typename(desc->obj->type),
519 remote);
520 goto cleanup;
521 }
522 }
523
524 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
525 oid_to_hex(&remote_head->object.oid), remote);
526 cleanup:
527 strbuf_release(&buf);
528 strbuf_release(&bname);
529 }
530
531 static void parse_branch_merge_options(char *bmo)
532 {
533 const char **argv;
534 int argc;
535
536 if (!bmo)
537 return;
538 argc = split_cmdline(bmo, &argv);
539 if (argc < 0)
540 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
541 split_cmdline_strerror(argc));
542 REALLOC_ARRAY(argv, argc + 2);
543 MOVE_ARRAY(argv + 1, argv, argc + 1);
544 argc++;
545 argv[0] = "branch.*.mergeoptions";
546 parse_options(argc, argv, NULL, builtin_merge_options,
547 builtin_merge_usage, 0);
548 free(argv);
549 }
550
551 static int git_merge_config(const char *k, const char *v, void *cb)
552 {
553 int status;
554
555 if (branch && starts_with(k, "branch.") &&
556 starts_with(k + 7, branch) &&
557 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
558 free(branch_mergeoptions);
559 branch_mergeoptions = xstrdup(v);
560 return 0;
561 }
562
563 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
564 show_diffstat = git_config_bool(k, v);
565 else if (!strcmp(k, "pull.twohead"))
566 return git_config_string(&pull_twohead, k, v);
567 else if (!strcmp(k, "pull.octopus"))
568 return git_config_string(&pull_octopus, k, v);
569 else if (!strcmp(k, "merge.renormalize"))
570 option_renormalize = git_config_bool(k, v);
571 else if (!strcmp(k, "merge.ff")) {
572 int boolval = git_parse_maybe_bool(v);
573 if (0 <= boolval) {
574 fast_forward = boolval ? FF_ALLOW : FF_NO;
575 } else if (v && !strcmp(v, "only")) {
576 fast_forward = FF_ONLY;
577 } /* do not barf on values from future versions of git */
578 return 0;
579 } else if (!strcmp(k, "merge.defaulttoupstream")) {
580 default_to_upstream = git_config_bool(k, v);
581 return 0;
582 } else if (!strcmp(k, "commit.gpgsign")) {
583 sign_commit = git_config_bool(k, v) ? "" : NULL;
584 return 0;
585 }
586
587 status = fmt_merge_msg_config(k, v, cb);
588 if (status)
589 return status;
590 status = git_gpg_config(k, v, NULL);
591 if (status)
592 return status;
593 return git_diff_ui_config(k, v, cb);
594 }
595
596 static int read_tree_trivial(struct object_id *common, struct object_id *head,
597 struct object_id *one)
598 {
599 int i, nr_trees = 0;
600 struct tree *trees[MAX_UNPACK_TREES];
601 struct tree_desc t[MAX_UNPACK_TREES];
602 struct unpack_trees_options opts;
603
604 memset(&opts, 0, sizeof(opts));
605 opts.head_idx = 2;
606 opts.src_index = &the_index;
607 opts.dst_index = &the_index;
608 opts.update = 1;
609 opts.verbose_update = 1;
610 opts.trivial_merges_only = 1;
611 opts.merge = 1;
612 trees[nr_trees] = parse_tree_indirect(common);
613 if (!trees[nr_trees++])
614 return -1;
615 trees[nr_trees] = parse_tree_indirect(head);
616 if (!trees[nr_trees++])
617 return -1;
618 trees[nr_trees] = parse_tree_indirect(one);
619 if (!trees[nr_trees++])
620 return -1;
621 opts.fn = threeway_merge;
622 cache_tree_free(&active_cache_tree);
623 for (i = 0; i < nr_trees; i++) {
624 parse_tree(trees[i]);
625 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
626 }
627 if (unpack_trees(nr_trees, t, &opts))
628 return -1;
629 return 0;
630 }
631
632 static void write_tree_trivial(struct object_id *oid)
633 {
634 if (write_cache_as_tree(oid->hash, 0, NULL))
635 die(_("git write-tree failed to write a tree"));
636 }
637
638 static int try_merge_strategy(const char *strategy, struct commit_list *common,
639 struct commit_list *remoteheads,
640 struct commit *head)
641 {
642 static struct lock_file lock;
643 const char *head_arg = "HEAD";
644
645 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
646 refresh_cache(REFRESH_QUIET);
647 if (active_cache_changed &&
648 write_locked_index(&the_index, &lock, COMMIT_LOCK))
649 return error(_("Unable to write index."));
650 rollback_lock_file(&lock);
651
652 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
653 int clean, x;
654 struct commit *result;
655 struct commit_list *reversed = NULL;
656 struct merge_options o;
657 struct commit_list *j;
658
659 if (remoteheads->next) {
660 error(_("Not handling anything other than two heads merge."));
661 return 2;
662 }
663
664 init_merge_options(&o);
665 if (!strcmp(strategy, "subtree"))
666 o.subtree_shift = "";
667
668 o.renormalize = option_renormalize;
669 o.show_rename_progress =
670 show_progress == -1 ? isatty(2) : show_progress;
671
672 for (x = 0; x < xopts_nr; x++)
673 if (parse_merge_opt(&o, xopts[x]))
674 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
675
676 o.branch1 = head_arg;
677 o.branch2 = merge_remote_util(remoteheads->item)->name;
678
679 for (j = common; j; j = j->next)
680 commit_list_insert(j->item, &reversed);
681
682 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
683 clean = merge_recursive(&o, head,
684 remoteheads->item, reversed, &result);
685 if (clean < 0)
686 exit(128);
687 if (active_cache_changed &&
688 write_locked_index(&the_index, &lock, COMMIT_LOCK))
689 die (_("unable to write %s"), get_index_file());
690 rollback_lock_file(&lock);
691 return clean ? 0 : 1;
692 } else {
693 return try_merge_command(strategy, xopts_nr, xopts,
694 common, head_arg, remoteheads);
695 }
696 }
697
698 static void count_diff_files(struct diff_queue_struct *q,
699 struct diff_options *opt, void *data)
700 {
701 int *count = data;
702
703 (*count) += q->nr;
704 }
705
706 static int count_unmerged_entries(void)
707 {
708 int i, ret = 0;
709
710 for (i = 0; i < active_nr; i++)
711 if (ce_stage(active_cache[i]))
712 ret++;
713
714 return ret;
715 }
716
717 static void add_strategies(const char *string, unsigned attr)
718 {
719 int i;
720
721 if (string) {
722 struct string_list list = STRING_LIST_INIT_DUP;
723 struct string_list_item *item;
724 string_list_split(&list, string, ' ', -1);
725 for_each_string_list_item(item, &list)
726 append_strategy(get_strategy(item->string));
727 string_list_clear(&list, 0);
728 return;
729 }
730 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
731 if (all_strategy[i].attr & attr)
732 append_strategy(&all_strategy[i]);
733
734 }
735
736 static void read_merge_msg(struct strbuf *msg)
737 {
738 const char *filename = git_path_merge_msg();
739 strbuf_reset(msg);
740 if (strbuf_read_file(msg, filename, 0) < 0)
741 die_errno(_("Could not read from '%s'"), filename);
742 }
743
744 static void write_merge_state(struct commit_list *);
745 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
746 {
747 if (err_msg)
748 error("%s", err_msg);
749 fprintf(stderr,
750 _("Not committing merge; use 'git commit' to complete the merge.\n"));
751 write_merge_state(remoteheads);
752 exit(1);
753 }
754
755 static const char merge_editor_comment[] =
756 N_("Please enter a commit message to explain why this merge is necessary,\n"
757 "especially if it merges an updated upstream into a topic branch.\n"
758 "\n"
759 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
760 "the commit.\n");
761
762 static void prepare_to_commit(struct commit_list *remoteheads)
763 {
764 struct strbuf msg = STRBUF_INIT;
765 strbuf_addbuf(&msg, &merge_msg);
766 strbuf_addch(&msg, '\n');
767 if (0 < option_edit)
768 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
769 if (signoff)
770 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
771 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
772 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
773 git_path_merge_msg(), "merge", NULL))
774 abort_commit(remoteheads, NULL);
775 if (0 < option_edit) {
776 if (launch_editor(git_path_merge_msg(), NULL, NULL))
777 abort_commit(remoteheads, NULL);
778 }
779 read_merge_msg(&msg);
780 strbuf_stripspace(&msg, 0 < option_edit);
781 if (!msg.len)
782 abort_commit(remoteheads, _("Empty commit message."));
783 strbuf_release(&merge_msg);
784 strbuf_addbuf(&merge_msg, &msg);
785 strbuf_release(&msg);
786 }
787
788 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
789 {
790 struct object_id result_tree, result_commit;
791 struct commit_list *parents, **pptr = &parents;
792 static struct lock_file lock;
793
794 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
795 refresh_cache(REFRESH_QUIET);
796 if (active_cache_changed &&
797 write_locked_index(&the_index, &lock, COMMIT_LOCK))
798 return error(_("Unable to write index."));
799 rollback_lock_file(&lock);
800
801 write_tree_trivial(&result_tree);
802 printf(_("Wonderful.\n"));
803 pptr = commit_list_append(head, pptr);
804 pptr = commit_list_append(remoteheads->item, pptr);
805 prepare_to_commit(remoteheads);
806 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
807 result_commit.hash, NULL, sign_commit))
808 die(_("failed to write commit object"));
809 finish(head, remoteheads, &result_commit, "In-index merge");
810 drop_save();
811 return 0;
812 }
813
814 static int finish_automerge(struct commit *head,
815 int head_subsumed,
816 struct commit_list *common,
817 struct commit_list *remoteheads,
818 struct object_id *result_tree,
819 const char *wt_strategy)
820 {
821 struct commit_list *parents = NULL;
822 struct strbuf buf = STRBUF_INIT;
823 struct object_id result_commit;
824
825 free_commit_list(common);
826 parents = remoteheads;
827 if (!head_subsumed || fast_forward == FF_NO)
828 commit_list_insert(head, &parents);
829 strbuf_addch(&merge_msg, '\n');
830 prepare_to_commit(remoteheads);
831 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
832 result_commit.hash, NULL, sign_commit))
833 die(_("failed to write commit object"));
834 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
835 finish(head, remoteheads, &result_commit, buf.buf);
836 strbuf_release(&buf);
837 drop_save();
838 return 0;
839 }
840
841 static int suggest_conflicts(void)
842 {
843 const char *filename;
844 FILE *fp;
845 struct strbuf msgbuf = STRBUF_INIT;
846
847 filename = git_path_merge_msg();
848 fp = xfopen(filename, "a");
849
850 append_conflicts_hint(&msgbuf);
851 fputs(msgbuf.buf, fp);
852 strbuf_release(&msgbuf);
853 fclose(fp);
854 rerere(allow_rerere_auto);
855 printf(_("Automatic merge failed; "
856 "fix conflicts and then commit the result.\n"));
857 return 1;
858 }
859
860 static int evaluate_result(void)
861 {
862 int cnt = 0;
863 struct rev_info rev;
864
865 /* Check how many files differ. */
866 init_revisions(&rev, "");
867 setup_revisions(0, NULL, &rev, NULL);
868 rev.diffopt.output_format |=
869 DIFF_FORMAT_CALLBACK;
870 rev.diffopt.format_callback = count_diff_files;
871 rev.diffopt.format_callback_data = &cnt;
872 run_diff_files(&rev, 0);
873
874 /*
875 * Check how many unmerged entries are
876 * there.
877 */
878 cnt += count_unmerged_entries();
879
880 return cnt;
881 }
882
883 /*
884 * Pretend as if the user told us to merge with the remote-tracking
885 * branch we have for the upstream of the current branch
886 */
887 static int setup_with_upstream(const char ***argv)
888 {
889 struct branch *branch = branch_get(NULL);
890 int i;
891 const char **args;
892
893 if (!branch)
894 die(_("No current branch."));
895 if (!branch->remote_name)
896 die(_("No remote for the current branch."));
897 if (!branch->merge_nr)
898 die(_("No default upstream defined for the current branch."));
899
900 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
901 for (i = 0; i < branch->merge_nr; i++) {
902 if (!branch->merge[i]->dst)
903 die(_("No remote-tracking branch for %s from %s"),
904 branch->merge[i]->src, branch->remote_name);
905 args[i] = branch->merge[i]->dst;
906 }
907 args[i] = NULL;
908 *argv = args;
909 return i;
910 }
911
912 static void write_merge_state(struct commit_list *remoteheads)
913 {
914 struct commit_list *j;
915 struct strbuf buf = STRBUF_INIT;
916
917 for (j = remoteheads; j; j = j->next) {
918 struct object_id *oid;
919 struct commit *c = j->item;
920 if (c->util && merge_remote_util(c)->obj) {
921 oid = &merge_remote_util(c)->obj->oid;
922 } else {
923 oid = &c->object.oid;
924 }
925 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
926 }
927 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
928 strbuf_addch(&merge_msg, '\n');
929 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
930
931 strbuf_reset(&buf);
932 if (fast_forward == FF_NO)
933 strbuf_addstr(&buf, "no-ff");
934 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
935 }
936
937 static int default_edit_option(void)
938 {
939 static const char name[] = "GIT_MERGE_AUTOEDIT";
940 const char *e = getenv(name);
941 struct stat st_stdin, st_stdout;
942
943 if (have_message)
944 /* an explicit -m msg without --[no-]edit */
945 return 0;
946
947 if (e) {
948 int v = git_parse_maybe_bool(e);
949 if (v < 0)
950 die(_("Bad value '%s' in environment '%s'"), e, name);
951 return v;
952 }
953
954 /* Use editor if stdin and stdout are the same and is a tty */
955 return (!fstat(0, &st_stdin) &&
956 !fstat(1, &st_stdout) &&
957 isatty(0) && isatty(1) &&
958 st_stdin.st_dev == st_stdout.st_dev &&
959 st_stdin.st_ino == st_stdout.st_ino &&
960 st_stdin.st_mode == st_stdout.st_mode);
961 }
962
963 static struct commit_list *reduce_parents(struct commit *head_commit,
964 int *head_subsumed,
965 struct commit_list *remoteheads)
966 {
967 struct commit_list *parents, **remotes;
968
969 /*
970 * Is the current HEAD reachable from another commit being
971 * merged? If so we do not want to record it as a parent of
972 * the resulting merge, unless --no-ff is given. We will flip
973 * this variable to 0 when we find HEAD among the independent
974 * tips being merged.
975 */
976 *head_subsumed = 1;
977
978 /* Find what parents to record by checking independent ones. */
979 parents = reduce_heads(remoteheads);
980
981 remoteheads = NULL;
982 remotes = &remoteheads;
983 while (parents) {
984 struct commit *commit = pop_commit(&parents);
985 if (commit == head_commit)
986 *head_subsumed = 0;
987 else
988 remotes = &commit_list_insert(commit, remotes)->next;
989 }
990 return remoteheads;
991 }
992
993 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
994 {
995 struct fmt_merge_msg_opts opts;
996
997 memset(&opts, 0, sizeof(opts));
998 opts.add_title = !have_message;
999 opts.shortlog_len = shortlog_len;
1000 opts.credit_people = (0 < option_edit);
1001
1002 fmt_merge_msg(merge_names, merge_msg, &opts);
1003 if (merge_msg->len)
1004 strbuf_setlen(merge_msg, merge_msg->len - 1);
1005 }
1006
1007 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1008 {
1009 const char *filename;
1010 int fd, pos, npos;
1011 struct strbuf fetch_head_file = STRBUF_INIT;
1012
1013 if (!merge_names)
1014 merge_names = &fetch_head_file;
1015
1016 filename = git_path_fetch_head();
1017 fd = open(filename, O_RDONLY);
1018 if (fd < 0)
1019 die_errno(_("could not open '%s' for reading"), filename);
1020
1021 if (strbuf_read(merge_names, fd, 0) < 0)
1022 die_errno(_("could not read '%s'"), filename);
1023 if (close(fd) < 0)
1024 die_errno(_("could not close '%s'"), filename);
1025
1026 for (pos = 0; pos < merge_names->len; pos = npos) {
1027 struct object_id oid;
1028 char *ptr;
1029 struct commit *commit;
1030
1031 ptr = strchr(merge_names->buf + pos, '\n');
1032 if (ptr)
1033 npos = ptr - merge_names->buf + 1;
1034 else
1035 npos = merge_names->len;
1036
1037 if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
1038 get_oid_hex(merge_names->buf + pos, &oid))
1039 commit = NULL; /* bad */
1040 else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
1041 continue; /* not-for-merge */
1042 else {
1043 char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
1044 merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
1045 commit = get_merge_parent(merge_names->buf + pos);
1046 merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
1047 }
1048 if (!commit) {
1049 if (ptr)
1050 *ptr = '\0';
1051 die(_("not something we can merge in %s: %s"),
1052 filename, merge_names->buf + pos);
1053 }
1054 remotes = &commit_list_insert(commit, remotes)->next;
1055 }
1056
1057 if (merge_names == &fetch_head_file)
1058 strbuf_release(&fetch_head_file);
1059 }
1060
1061 static struct commit_list *collect_parents(struct commit *head_commit,
1062 int *head_subsumed,
1063 int argc, const char **argv,
1064 struct strbuf *merge_msg)
1065 {
1066 int i;
1067 struct commit_list *remoteheads = NULL;
1068 struct commit_list **remotes = &remoteheads;
1069 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1070
1071 if (merge_msg && (!have_message || shortlog_len))
1072 autogen = &merge_names;
1073
1074 if (head_commit)
1075 remotes = &commit_list_insert(head_commit, remotes)->next;
1076
1077 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1078 handle_fetch_head(remotes, autogen);
1079 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1080 } else {
1081 for (i = 0; i < argc; i++) {
1082 struct commit *commit = get_merge_parent(argv[i]);
1083 if (!commit)
1084 help_unknown_ref(argv[i], "merge",
1085 _("not something we can merge"));
1086 remotes = &commit_list_insert(commit, remotes)->next;
1087 }
1088 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1089 if (autogen) {
1090 struct commit_list *p;
1091 for (p = remoteheads; p; p = p->next)
1092 merge_name(merge_remote_util(p->item)->name, autogen);
1093 }
1094 }
1095
1096 if (autogen) {
1097 prepare_merge_message(autogen, merge_msg);
1098 strbuf_release(autogen);
1099 }
1100
1101 return remoteheads;
1102 }
1103
1104 int cmd_merge(int argc, const char **argv, const char *prefix)
1105 {
1106 struct object_id result_tree, stash, head_oid;
1107 struct commit *head_commit;
1108 struct strbuf buf = STRBUF_INIT;
1109 int i, ret = 0, head_subsumed;
1110 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1111 struct commit_list *common = NULL;
1112 const char *best_strategy = NULL, *wt_strategy = NULL;
1113 struct commit_list *remoteheads, *p;
1114 void *branch_to_free;
1115 int orig_argc = argc;
1116
1117 if (argc == 2 && !strcmp(argv[1], "-h"))
1118 usage_with_options(builtin_merge_usage, builtin_merge_options);
1119
1120 /*
1121 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1122 * current branch.
1123 */
1124 branch = branch_to_free = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
1125 if (branch)
1126 skip_prefix(branch, "refs/heads/", &branch);
1127 if (!branch || is_null_oid(&head_oid))
1128 head_commit = NULL;
1129 else
1130 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1131
1132 init_diff_ui_defaults();
1133 git_config(git_merge_config, NULL);
1134
1135 if (branch_mergeoptions)
1136 parse_branch_merge_options(branch_mergeoptions);
1137 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1138 builtin_merge_usage, 0);
1139 if (shortlog_len < 0)
1140 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1141
1142 if (verbosity < 0 && show_progress == -1)
1143 show_progress = 0;
1144
1145 if (abort_current_merge) {
1146 int nargc = 2;
1147 const char *nargv[] = {"reset", "--merge", NULL};
1148
1149 if (orig_argc != 2)
1150 usage_msg_opt(_("--abort expects no arguments"),
1151 builtin_merge_usage, builtin_merge_options);
1152
1153 if (!file_exists(git_path_merge_head()))
1154 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1155
1156 /* Invoke 'git reset --merge' */
1157 ret = cmd_reset(nargc, nargv, prefix);
1158 goto done;
1159 }
1160
1161 if (continue_current_merge) {
1162 int nargc = 1;
1163 const char *nargv[] = {"commit", NULL};
1164
1165 if (orig_argc != 2)
1166 usage_msg_opt(_("--continue expects no arguments"),
1167 builtin_merge_usage, builtin_merge_options);
1168
1169 if (!file_exists(git_path_merge_head()))
1170 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1171
1172 /* Invoke 'git commit' */
1173 ret = cmd_commit(nargc, nargv, prefix);
1174 goto done;
1175 }
1176
1177 if (read_cache_unmerged())
1178 die_resolve_conflict("merge");
1179
1180 if (file_exists(git_path_merge_head())) {
1181 /*
1182 * There is no unmerged entry, don't advise 'git
1183 * add/rm <file>', just 'git commit'.
1184 */
1185 if (advice_resolve_conflict)
1186 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1187 "Please, commit your changes before you merge."));
1188 else
1189 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1190 }
1191 if (file_exists(git_path_cherry_pick_head())) {
1192 if (advice_resolve_conflict)
1193 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1194 "Please, commit your changes before you merge."));
1195 else
1196 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1197 }
1198 resolve_undo_clear();
1199
1200 if (verbosity < 0)
1201 show_diffstat = 0;
1202
1203 if (squash) {
1204 if (fast_forward == FF_NO)
1205 die(_("You cannot combine --squash with --no-ff."));
1206 option_commit = 0;
1207 }
1208
1209 if (!argc) {
1210 if (default_to_upstream)
1211 argc = setup_with_upstream(&argv);
1212 else
1213 die(_("No commit specified and merge.defaultToUpstream not set."));
1214 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1215 argv[0] = "@{-1}";
1216 }
1217
1218 if (!argc)
1219 usage_with_options(builtin_merge_usage,
1220 builtin_merge_options);
1221
1222 if (!head_commit) {
1223 /*
1224 * If the merged head is a valid one there is no reason
1225 * to forbid "git merge" into a branch yet to be born.
1226 * We do the same for "git pull".
1227 */
1228 struct object_id *remote_head_oid;
1229 if (squash)
1230 die(_("Squash commit into empty head not supported yet"));
1231 if (fast_forward == FF_NO)
1232 die(_("Non-fast-forward commit does not make sense into "
1233 "an empty head"));
1234 remoteheads = collect_parents(head_commit, &head_subsumed,
1235 argc, argv, NULL);
1236 if (!remoteheads)
1237 die(_("%s - not something we can merge"), argv[0]);
1238 if (remoteheads->next)
1239 die(_("Can merge only exactly one commit into empty head"));
1240 remote_head_oid = &remoteheads->item->object.oid;
1241 read_empty(remote_head_oid->hash, 0);
1242 update_ref("initial pull", "HEAD", remote_head_oid->hash,
1243 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1244 goto done;
1245 }
1246
1247 /*
1248 * All the rest are the commits being merged; prepare
1249 * the standard merge summary message to be appended
1250 * to the given message.
1251 */
1252 remoteheads = collect_parents(head_commit, &head_subsumed,
1253 argc, argv, &merge_msg);
1254
1255 if (!head_commit || !argc)
1256 usage_with_options(builtin_merge_usage,
1257 builtin_merge_options);
1258
1259 if (verify_signatures) {
1260 for (p = remoteheads; p; p = p->next) {
1261 struct commit *commit = p->item;
1262 char hex[GIT_MAX_HEXSZ + 1];
1263 struct signature_check signature_check;
1264 memset(&signature_check, 0, sizeof(signature_check));
1265
1266 check_commit_signature(commit, &signature_check);
1267
1268 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1269 switch (signature_check.result) {
1270 case 'G':
1271 break;
1272 case 'U':
1273 die(_("Commit %s has an untrusted GPG signature, "
1274 "allegedly by %s."), hex, signature_check.signer);
1275 case 'B':
1276 die(_("Commit %s has a bad GPG signature "
1277 "allegedly by %s."), hex, signature_check.signer);
1278 default: /* 'N' */
1279 die(_("Commit %s does not have a GPG signature."), hex);
1280 }
1281 if (verbosity >= 0 && signature_check.result == 'G')
1282 printf(_("Commit %s has a good GPG signature by %s\n"),
1283 hex, signature_check.signer);
1284
1285 signature_check_clear(&signature_check);
1286 }
1287 }
1288
1289 strbuf_addstr(&buf, "merge");
1290 for (p = remoteheads; p; p = p->next)
1291 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1292 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1293 strbuf_reset(&buf);
1294
1295 for (p = remoteheads; p; p = p->next) {
1296 struct commit *commit = p->item;
1297 strbuf_addf(&buf, "GITHEAD_%s",
1298 oid_to_hex(&commit->object.oid));
1299 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1300 strbuf_reset(&buf);
1301 if (fast_forward != FF_ONLY &&
1302 merge_remote_util(commit) &&
1303 merge_remote_util(commit)->obj &&
1304 merge_remote_util(commit)->obj->type == OBJ_TAG)
1305 fast_forward = FF_NO;
1306 }
1307
1308 if (option_edit < 0)
1309 option_edit = default_edit_option();
1310
1311 if (!use_strategies) {
1312 if (!remoteheads)
1313 ; /* already up-to-date */
1314 else if (!remoteheads->next)
1315 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1316 else
1317 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1318 }
1319
1320 for (i = 0; i < use_strategies_nr; i++) {
1321 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1322 fast_forward = FF_NO;
1323 if (use_strategies[i]->attr & NO_TRIVIAL)
1324 allow_trivial = 0;
1325 }
1326
1327 if (!remoteheads)
1328 ; /* already up-to-date */
1329 else if (!remoteheads->next)
1330 common = get_merge_bases(head_commit, remoteheads->item);
1331 else {
1332 struct commit_list *list = remoteheads;
1333 commit_list_insert(head_commit, &list);
1334 common = get_octopus_merge_bases(list);
1335 free(list);
1336 }
1337
1338 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
1339 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1340
1341 if (remoteheads && !common) {
1342 /* No common ancestors found. */
1343 if (!allow_unrelated_histories)
1344 die(_("refusing to merge unrelated histories"));
1345 /* otherwise, we need a real merge. */
1346 } else if (!remoteheads ||
1347 (!remoteheads->next && !common->next &&
1348 common->item == remoteheads->item)) {
1349 /*
1350 * If head can reach all the merge then we are up to date.
1351 * but first the most common case of merging one remote.
1352 */
1353 finish_up_to_date(_("Already up-to-date."));
1354 goto done;
1355 } else if (fast_forward != FF_NO && !remoteheads->next &&
1356 !common->next &&
1357 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1358 /* Again the most common case of merging one remote. */
1359 struct strbuf msg = STRBUF_INIT;
1360 struct commit *commit;
1361
1362 if (verbosity >= 0) {
1363 printf(_("Updating %s..%s\n"),
1364 find_unique_abbrev(head_commit->object.oid.hash,
1365 DEFAULT_ABBREV),
1366 find_unique_abbrev(remoteheads->item->object.oid.hash,
1367 DEFAULT_ABBREV));
1368 }
1369 strbuf_addstr(&msg, "Fast-forward");
1370 if (have_message)
1371 strbuf_addstr(&msg,
1372 " (no commit created; -m option ignored)");
1373 commit = remoteheads->item;
1374 if (!commit) {
1375 ret = 1;
1376 goto done;
1377 }
1378
1379 if (checkout_fast_forward(&head_commit->object.oid,
1380 &commit->object.oid,
1381 overwrite_ignore)) {
1382 ret = 1;
1383 goto done;
1384 }
1385
1386 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1387 drop_save();
1388 goto done;
1389 } else if (!remoteheads->next && common->next)
1390 ;
1391 /*
1392 * We are not doing octopus and not fast-forward. Need
1393 * a real merge.
1394 */
1395 else if (!remoteheads->next && !common->next && option_commit) {
1396 /*
1397 * We are not doing octopus, not fast-forward, and have
1398 * only one common.
1399 */
1400 refresh_cache(REFRESH_QUIET);
1401 if (allow_trivial && fast_forward != FF_ONLY) {
1402 /* See if it is really trivial. */
1403 git_committer_info(IDENT_STRICT);
1404 printf(_("Trying really trivial in-index merge...\n"));
1405 if (!read_tree_trivial(&common->item->object.oid,
1406 &head_commit->object.oid,
1407 &remoteheads->item->object.oid)) {
1408 ret = merge_trivial(head_commit, remoteheads);
1409 goto done;
1410 }
1411 printf(_("Nope.\n"));
1412 }
1413 } else {
1414 /*
1415 * An octopus. If we can reach all the remote we are up
1416 * to date.
1417 */
1418 int up_to_date = 1;
1419 struct commit_list *j;
1420
1421 for (j = remoteheads; j; j = j->next) {
1422 struct commit_list *common_one;
1423
1424 /*
1425 * Here we *have* to calculate the individual
1426 * merge_bases again, otherwise "git merge HEAD^
1427 * HEAD^^" would be missed.
1428 */
1429 common_one = get_merge_bases(head_commit, j->item);
1430 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1431 up_to_date = 0;
1432 break;
1433 }
1434 }
1435 if (up_to_date) {
1436 finish_up_to_date(_("Already up-to-date. Yeeah!"));
1437 goto done;
1438 }
1439 }
1440
1441 if (fast_forward == FF_ONLY)
1442 die(_("Not possible to fast-forward, aborting."));
1443
1444 /* We are going to make a new commit. */
1445 git_committer_info(IDENT_STRICT);
1446
1447 /*
1448 * At this point, we need a real merge. No matter what strategy
1449 * we use, it would operate on the index, possibly affecting the
1450 * working tree, and when resolved cleanly, have the desired
1451 * tree in the index -- this means that the index must be in
1452 * sync with the head commit. The strategies are responsible
1453 * to ensure this.
1454 */
1455 if (use_strategies_nr == 1 ||
1456 /*
1457 * Stash away the local changes so that we can try more than one.
1458 */
1459 save_state(&stash))
1460 oidclr(&stash);
1461
1462 for (i = 0; i < use_strategies_nr; i++) {
1463 int ret;
1464 if (i) {
1465 printf(_("Rewinding the tree to pristine...\n"));
1466 restore_state(&head_commit->object.oid, &stash);
1467 }
1468 if (use_strategies_nr != 1)
1469 printf(_("Trying merge strategy %s...\n"),
1470 use_strategies[i]->name);
1471 /*
1472 * Remember which strategy left the state in the working
1473 * tree.
1474 */
1475 wt_strategy = use_strategies[i]->name;
1476
1477 ret = try_merge_strategy(use_strategies[i]->name,
1478 common, remoteheads,
1479 head_commit);
1480 if (!option_commit && !ret) {
1481 merge_was_ok = 1;
1482 /*
1483 * This is necessary here just to avoid writing
1484 * the tree, but later we will *not* exit with
1485 * status code 1 because merge_was_ok is set.
1486 */
1487 ret = 1;
1488 }
1489
1490 if (ret) {
1491 /*
1492 * The backend exits with 1 when conflicts are
1493 * left to be resolved, with 2 when it does not
1494 * handle the given merge at all.
1495 */
1496 if (ret == 1) {
1497 int cnt = evaluate_result();
1498
1499 if (best_cnt <= 0 || cnt <= best_cnt) {
1500 best_strategy = use_strategies[i]->name;
1501 best_cnt = cnt;
1502 }
1503 }
1504 if (merge_was_ok)
1505 break;
1506 else
1507 continue;
1508 }
1509
1510 /* Automerge succeeded. */
1511 write_tree_trivial(&result_tree);
1512 automerge_was_ok = 1;
1513 break;
1514 }
1515
1516 /*
1517 * If we have a resulting tree, that means the strategy module
1518 * auto resolved the merge cleanly.
1519 */
1520 if (automerge_was_ok) {
1521 ret = finish_automerge(head_commit, head_subsumed,
1522 common, remoteheads,
1523 &result_tree, wt_strategy);
1524 goto done;
1525 }
1526
1527 /*
1528 * Pick the result from the best strategy and have the user fix
1529 * it up.
1530 */
1531 if (!best_strategy) {
1532 restore_state(&head_commit->object.oid, &stash);
1533 if (use_strategies_nr > 1)
1534 fprintf(stderr,
1535 _("No merge strategy handled the merge.\n"));
1536 else
1537 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1538 use_strategies[0]->name);
1539 ret = 2;
1540 goto done;
1541 } else if (best_strategy == wt_strategy)
1542 ; /* We already have its result in the working tree. */
1543 else {
1544 printf(_("Rewinding the tree to pristine...\n"));
1545 restore_state(&head_commit->object.oid, &stash);
1546 printf(_("Using the %s to prepare resolving by hand.\n"),
1547 best_strategy);
1548 try_merge_strategy(best_strategy, common, remoteheads,
1549 head_commit);
1550 }
1551
1552 if (squash)
1553 finish(head_commit, remoteheads, NULL, NULL);
1554 else
1555 write_merge_state(remoteheads);
1556
1557 if (merge_was_ok)
1558 fprintf(stderr, _("Automatic merge went well; "
1559 "stopped before committing as requested\n"));
1560 else
1561 ret = suggest_conflicts();
1562
1563 done:
1564 free(branch_to_free);
1565 return ret;
1566 }