Merge branch 'tg/deprecate-stash-save'
[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 static int verify_msg = 1;
77
78 static struct strategy all_strategy[] = {
79 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
80 { "octopus", DEFAULT_OCTOPUS },
81 { "resolve", 0 },
82 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
83 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
84 };
85
86 static const char *pull_twohead, *pull_octopus;
87
88 enum ff_type {
89 FF_NO,
90 FF_ALLOW,
91 FF_ONLY
92 };
93
94 static enum ff_type fast_forward = FF_ALLOW;
95
96 static int option_parse_message(const struct option *opt,
97 const char *arg, int unset)
98 {
99 struct strbuf *buf = opt->value;
100
101 if (unset)
102 strbuf_setlen(buf, 0);
103 else if (arg) {
104 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
105 have_message = 1;
106 } else
107 return error(_("switch `m' requires a value"));
108 return 0;
109 }
110
111 static struct strategy *get_strategy(const char *name)
112 {
113 int i;
114 struct strategy *ret;
115 static struct cmdnames main_cmds, other_cmds;
116 static int loaded;
117
118 if (!name)
119 return NULL;
120
121 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
122 if (!strcmp(name, all_strategy[i].name))
123 return &all_strategy[i];
124
125 if (!loaded) {
126 struct cmdnames not_strategies;
127 loaded = 1;
128
129 memset(&not_strategies, 0, sizeof(struct cmdnames));
130 load_command_list("git-merge-", &main_cmds, &other_cmds);
131 for (i = 0; i < main_cmds.cnt; i++) {
132 int j, found = 0;
133 struct cmdname *ent = main_cmds.names[i];
134 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
135 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
136 && !all_strategy[j].name[ent->len])
137 found = 1;
138 if (!found)
139 add_cmdname(&not_strategies, ent->name, ent->len);
140 }
141 exclude_cmds(&main_cmds, &not_strategies);
142 }
143 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
144 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
145 fprintf(stderr, _("Available strategies are:"));
146 for (i = 0; i < main_cmds.cnt; i++)
147 fprintf(stderr, " %s", main_cmds.names[i]->name);
148 fprintf(stderr, ".\n");
149 if (other_cmds.cnt) {
150 fprintf(stderr, _("Available custom strategies are:"));
151 for (i = 0; i < other_cmds.cnt; i++)
152 fprintf(stderr, " %s", other_cmds.names[i]->name);
153 fprintf(stderr, ".\n");
154 }
155 exit(1);
156 }
157
158 ret = xcalloc(1, sizeof(struct strategy));
159 ret->name = xstrdup(name);
160 ret->attr = NO_TRIVIAL;
161 return ret;
162 }
163
164 static void append_strategy(struct strategy *s)
165 {
166 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
167 use_strategies[use_strategies_nr++] = s;
168 }
169
170 static int option_parse_strategy(const struct option *opt,
171 const char *name, int unset)
172 {
173 if (unset)
174 return 0;
175
176 append_strategy(get_strategy(name));
177 return 0;
178 }
179
180 static int option_parse_x(const struct option *opt,
181 const char *arg, int unset)
182 {
183 if (unset)
184 return 0;
185
186 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
187 xopts[xopts_nr++] = xstrdup(arg);
188 return 0;
189 }
190
191 static int option_parse_n(const struct option *opt,
192 const char *arg, int unset)
193 {
194 show_diffstat = unset;
195 return 0;
196 }
197
198 static struct option builtin_merge_options[] = {
199 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
200 N_("do not show a diffstat at the end of the merge"),
201 PARSE_OPT_NOARG, option_parse_n },
202 OPT_BOOL(0, "stat", &show_diffstat,
203 N_("show a diffstat at the end of the merge")),
204 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
205 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
206 N_("add (at most <n>) entries from shortlog to merge commit message"),
207 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
208 OPT_BOOL(0, "squash", &squash,
209 N_("create a single commit instead of doing a merge")),
210 OPT_BOOL(0, "commit", &option_commit,
211 N_("perform a commit if the merge succeeds (default)")),
212 OPT_BOOL('e', "edit", &option_edit,
213 N_("edit message before committing")),
214 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
215 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
216 N_("abort if fast-forward is not possible"),
217 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
218 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
219 OPT_BOOL(0, "verify-signatures", &verify_signatures,
220 N_("verify that the named commit has a valid GPG signature")),
221 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
222 N_("merge strategy to use"), option_parse_strategy),
223 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
224 N_("option for selected merge strategy"), option_parse_x),
225 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
226 N_("merge commit message (for a non-fast-forward merge)"),
227 option_parse_message),
228 OPT__VERBOSITY(&verbosity),
229 OPT_BOOL(0, "abort", &abort_current_merge,
230 N_("abort the current in-progress merge")),
231 OPT_BOOL(0, "continue", &continue_current_merge,
232 N_("continue the current in-progress merge")),
233 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
234 N_("allow merging unrelated histories")),
235 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
236 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
237 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
238 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
239 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
240 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
241 OPT_END()
242 };
243
244 /* Cleans up metadata that is uninteresting after a succeeded merge. */
245 static void drop_save(void)
246 {
247 unlink(git_path_merge_head());
248 unlink(git_path_merge_msg());
249 unlink(git_path_merge_mode());
250 }
251
252 static int save_state(struct object_id *stash)
253 {
254 int len;
255 struct child_process cp = CHILD_PROCESS_INIT;
256 struct strbuf buffer = STRBUF_INIT;
257 const char *argv[] = {"stash", "create", NULL};
258 int rc = -1;
259
260 cp.argv = argv;
261 cp.out = -1;
262 cp.git_cmd = 1;
263
264 if (start_command(&cp))
265 die(_("could not run stash."));
266 len = strbuf_read(&buffer, cp.out, 1024);
267 close(cp.out);
268
269 if (finish_command(&cp) || len < 0)
270 die(_("stash failed"));
271 else if (!len) /* no changes */
272 goto out;
273 strbuf_setlen(&buffer, buffer.len-1);
274 if (get_oid(buffer.buf, stash))
275 die(_("not a valid object: %s"), buffer.buf);
276 rc = 0;
277 out:
278 strbuf_release(&buffer);
279 return rc;
280 }
281
282 static void read_empty(unsigned const char *sha1, int verbose)
283 {
284 int i = 0;
285 const char *args[7];
286
287 args[i++] = "read-tree";
288 if (verbose)
289 args[i++] = "-v";
290 args[i++] = "-m";
291 args[i++] = "-u";
292 args[i++] = EMPTY_TREE_SHA1_HEX;
293 args[i++] = sha1_to_hex(sha1);
294 args[i] = NULL;
295
296 if (run_command_v_opt(args, RUN_GIT_CMD))
297 die(_("read-tree failed"));
298 }
299
300 static void reset_hard(unsigned const char *sha1, int verbose)
301 {
302 int i = 0;
303 const char *args[6];
304
305 args[i++] = "read-tree";
306 if (verbose)
307 args[i++] = "-v";
308 args[i++] = "--reset";
309 args[i++] = "-u";
310 args[i++] = sha1_to_hex(sha1);
311 args[i] = NULL;
312
313 if (run_command_v_opt(args, RUN_GIT_CMD))
314 die(_("read-tree failed"));
315 }
316
317 static void restore_state(const struct object_id *head,
318 const struct object_id *stash)
319 {
320 struct strbuf sb = STRBUF_INIT;
321 const char *args[] = { "stash", "apply", NULL, NULL };
322
323 if (is_null_oid(stash))
324 return;
325
326 reset_hard(head->hash, 1);
327
328 args[2] = oid_to_hex(stash);
329
330 /*
331 * It is OK to ignore error here, for example when there was
332 * nothing to restore.
333 */
334 run_command_v_opt(args, RUN_GIT_CMD);
335
336 strbuf_release(&sb);
337 refresh_cache(REFRESH_QUIET);
338 }
339
340 /* This is called when no merge was necessary. */
341 static void finish_up_to_date(const char *msg)
342 {
343 if (verbosity >= 0)
344 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
345 drop_save();
346 }
347
348 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
349 {
350 struct rev_info rev;
351 struct strbuf out = STRBUF_INIT;
352 struct commit_list *j;
353 struct pretty_print_context ctx = {0};
354
355 printf(_("Squash commit -- not updating HEAD\n"));
356
357 init_revisions(&rev, NULL);
358 rev.ignore_merges = 1;
359 rev.commit_format = CMIT_FMT_MEDIUM;
360
361 commit->object.flags |= UNINTERESTING;
362 add_pending_object(&rev, &commit->object, NULL);
363
364 for (j = remoteheads; j; j = j->next)
365 add_pending_object(&rev, &j->item->object, NULL);
366
367 setup_revisions(0, NULL, &rev, NULL);
368 if (prepare_revision_walk(&rev))
369 die(_("revision walk setup failed"));
370
371 ctx.abbrev = rev.abbrev;
372 ctx.date_mode = rev.date_mode;
373 ctx.fmt = rev.commit_format;
374
375 strbuf_addstr(&out, "Squashed commit of the following:\n");
376 while ((commit = get_revision(&rev)) != NULL) {
377 strbuf_addch(&out, '\n');
378 strbuf_addf(&out, "commit %s\n",
379 oid_to_hex(&commit->object.oid));
380 pretty_print_commit(&ctx, commit, &out);
381 }
382 write_file_buf(git_path_squash_msg(), out.buf, out.len);
383 strbuf_release(&out);
384 }
385
386 static void finish(struct commit *head_commit,
387 struct commit_list *remoteheads,
388 const struct object_id *new_head, const char *msg)
389 {
390 struct strbuf reflog_message = STRBUF_INIT;
391 const struct object_id *head = &head_commit->object.oid;
392
393 if (!msg)
394 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
395 else {
396 if (verbosity >= 0)
397 printf("%s\n", msg);
398 strbuf_addf(&reflog_message, "%s: %s",
399 getenv("GIT_REFLOG_ACTION"), msg);
400 }
401 if (squash) {
402 squash_message(head_commit, remoteheads);
403 } else {
404 if (verbosity >= 0 && !merge_msg.len)
405 printf(_("No merge message -- not updating HEAD\n"));
406 else {
407 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
408 update_ref(reflog_message.buf, "HEAD", new_head, head,
409 0, UPDATE_REFS_DIE_ON_ERR);
410 /*
411 * We ignore errors in 'gc --auto', since the
412 * user should see them.
413 */
414 close_all_packs();
415 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
416 }
417 }
418 if (new_head && show_diffstat) {
419 struct diff_options opts;
420 diff_setup(&opts);
421 opts.stat_width = -1; /* use full terminal width */
422 opts.stat_graph_width = -1; /* respect statGraphWidth config */
423 opts.output_format |=
424 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
425 opts.detect_rename = DIFF_DETECT_RENAME;
426 diff_setup_done(&opts);
427 diff_tree_oid(head, new_head, "", &opts);
428 diffcore_std(&opts);
429 diff_flush(&opts);
430 }
431
432 /* Run a post-merge hook */
433 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
434
435 strbuf_release(&reflog_message);
436 }
437
438 /* Get the name for the merge commit's message. */
439 static void merge_name(const char *remote, struct strbuf *msg)
440 {
441 struct commit *remote_head;
442 struct object_id branch_head;
443 struct strbuf buf = STRBUF_INIT;
444 struct strbuf bname = STRBUF_INIT;
445 const char *ptr;
446 char *found_ref;
447 int len, early;
448
449 strbuf_branchname(&bname, remote, 0);
450 remote = bname.buf;
451
452 oidclr(&branch_head);
453 remote_head = get_merge_parent(remote);
454 if (!remote_head)
455 die(_("'%s' does not point to a commit"), remote);
456
457 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
458 if (starts_with(found_ref, "refs/heads/")) {
459 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
460 oid_to_hex(&branch_head), remote);
461 goto cleanup;
462 }
463 if (starts_with(found_ref, "refs/tags/")) {
464 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
465 oid_to_hex(&branch_head), remote);
466 goto cleanup;
467 }
468 if (starts_with(found_ref, "refs/remotes/")) {
469 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
470 oid_to_hex(&branch_head), remote);
471 goto cleanup;
472 }
473 }
474
475 /* See if remote matches <name>^^^.. or <name>~<number> */
476 for (len = 0, ptr = remote + strlen(remote);
477 remote < ptr && ptr[-1] == '^';
478 ptr--)
479 len++;
480 if (len)
481 early = 1;
482 else {
483 early = 0;
484 ptr = strrchr(remote, '~');
485 if (ptr) {
486 int seen_nonzero = 0;
487
488 len++; /* count ~ */
489 while (*++ptr && isdigit(*ptr)) {
490 seen_nonzero |= (*ptr != '0');
491 len++;
492 }
493 if (*ptr)
494 len = 0; /* not ...~<number> */
495 else if (seen_nonzero)
496 early = 1;
497 else if (len == 1)
498 early = 1; /* "name~" is "name~1"! */
499 }
500 }
501 if (len) {
502 struct strbuf truname = STRBUF_INIT;
503 strbuf_addf(&truname, "refs/heads/%s", remote);
504 strbuf_setlen(&truname, truname.len - len);
505 if (ref_exists(truname.buf)) {
506 strbuf_addf(msg,
507 "%s\t\tbranch '%s'%s of .\n",
508 oid_to_hex(&remote_head->object.oid),
509 truname.buf + 11,
510 (early ? " (early part)" : ""));
511 strbuf_release(&truname);
512 goto cleanup;
513 }
514 strbuf_release(&truname);
515 }
516
517 if (remote_head->util) {
518 struct merge_remote_desc *desc;
519 desc = merge_remote_util(remote_head);
520 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
521 strbuf_addf(msg, "%s\t\t%s '%s'\n",
522 oid_to_hex(&desc->obj->oid),
523 typename(desc->obj->type),
524 remote);
525 goto cleanup;
526 }
527 }
528
529 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
530 oid_to_hex(&remote_head->object.oid), remote);
531 cleanup:
532 strbuf_release(&buf);
533 strbuf_release(&bname);
534 }
535
536 static void parse_branch_merge_options(char *bmo)
537 {
538 const char **argv;
539 int argc;
540
541 if (!bmo)
542 return;
543 argc = split_cmdline(bmo, &argv);
544 if (argc < 0)
545 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
546 split_cmdline_strerror(argc));
547 REALLOC_ARRAY(argv, argc + 2);
548 MOVE_ARRAY(argv + 1, argv, argc + 1);
549 argc++;
550 argv[0] = "branch.*.mergeoptions";
551 parse_options(argc, argv, NULL, builtin_merge_options,
552 builtin_merge_usage, 0);
553 free(argv);
554 }
555
556 static int git_merge_config(const char *k, const char *v, void *cb)
557 {
558 int status;
559
560 if (branch && starts_with(k, "branch.") &&
561 starts_with(k + 7, branch) &&
562 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
563 free(branch_mergeoptions);
564 branch_mergeoptions = xstrdup(v);
565 return 0;
566 }
567
568 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
569 show_diffstat = git_config_bool(k, v);
570 else if (!strcmp(k, "pull.twohead"))
571 return git_config_string(&pull_twohead, k, v);
572 else if (!strcmp(k, "pull.octopus"))
573 return git_config_string(&pull_octopus, k, v);
574 else if (!strcmp(k, "merge.renormalize"))
575 option_renormalize = git_config_bool(k, v);
576 else if (!strcmp(k, "merge.ff")) {
577 int boolval = git_parse_maybe_bool(v);
578 if (0 <= boolval) {
579 fast_forward = boolval ? FF_ALLOW : FF_NO;
580 } else if (v && !strcmp(v, "only")) {
581 fast_forward = FF_ONLY;
582 } /* do not barf on values from future versions of git */
583 return 0;
584 } else if (!strcmp(k, "merge.defaulttoupstream")) {
585 default_to_upstream = git_config_bool(k, v);
586 return 0;
587 } else if (!strcmp(k, "commit.gpgsign")) {
588 sign_commit = git_config_bool(k, v) ? "" : NULL;
589 return 0;
590 }
591
592 status = fmt_merge_msg_config(k, v, cb);
593 if (status)
594 return status;
595 status = git_gpg_config(k, v, NULL);
596 if (status)
597 return status;
598 return git_diff_ui_config(k, v, cb);
599 }
600
601 static int read_tree_trivial(struct object_id *common, struct object_id *head,
602 struct object_id *one)
603 {
604 int i, nr_trees = 0;
605 struct tree *trees[MAX_UNPACK_TREES];
606 struct tree_desc t[MAX_UNPACK_TREES];
607 struct unpack_trees_options opts;
608
609 memset(&opts, 0, sizeof(opts));
610 opts.head_idx = 2;
611 opts.src_index = &the_index;
612 opts.dst_index = &the_index;
613 opts.update = 1;
614 opts.verbose_update = 1;
615 opts.trivial_merges_only = 1;
616 opts.merge = 1;
617 trees[nr_trees] = parse_tree_indirect(common);
618 if (!trees[nr_trees++])
619 return -1;
620 trees[nr_trees] = parse_tree_indirect(head);
621 if (!trees[nr_trees++])
622 return -1;
623 trees[nr_trees] = parse_tree_indirect(one);
624 if (!trees[nr_trees++])
625 return -1;
626 opts.fn = threeway_merge;
627 cache_tree_free(&active_cache_tree);
628 for (i = 0; i < nr_trees; i++) {
629 parse_tree(trees[i]);
630 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
631 }
632 if (unpack_trees(nr_trees, t, &opts))
633 return -1;
634 return 0;
635 }
636
637 static void write_tree_trivial(struct object_id *oid)
638 {
639 if (write_cache_as_tree(oid->hash, 0, NULL))
640 die(_("git write-tree failed to write a tree"));
641 }
642
643 static int try_merge_strategy(const char *strategy, struct commit_list *common,
644 struct commit_list *remoteheads,
645 struct commit *head)
646 {
647 static struct lock_file lock;
648 const char *head_arg = "HEAD";
649
650 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
651 refresh_cache(REFRESH_QUIET);
652 if (active_cache_changed &&
653 write_locked_index(&the_index, &lock, COMMIT_LOCK))
654 return error(_("Unable to write index."));
655 rollback_lock_file(&lock);
656
657 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
658 int clean, x;
659 struct commit *result;
660 struct commit_list *reversed = NULL;
661 struct merge_options o;
662 struct commit_list *j;
663
664 if (remoteheads->next) {
665 error(_("Not handling anything other than two heads merge."));
666 return 2;
667 }
668
669 init_merge_options(&o);
670 if (!strcmp(strategy, "subtree"))
671 o.subtree_shift = "";
672
673 o.renormalize = option_renormalize;
674 o.show_rename_progress =
675 show_progress == -1 ? isatty(2) : show_progress;
676
677 for (x = 0; x < xopts_nr; x++)
678 if (parse_merge_opt(&o, xopts[x]))
679 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
680
681 o.branch1 = head_arg;
682 o.branch2 = merge_remote_util(remoteheads->item)->name;
683
684 for (j = common; j; j = j->next)
685 commit_list_insert(j->item, &reversed);
686
687 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
688 clean = merge_recursive(&o, head,
689 remoteheads->item, reversed, &result);
690 if (clean < 0)
691 exit(128);
692 if (active_cache_changed &&
693 write_locked_index(&the_index, &lock, COMMIT_LOCK))
694 die (_("unable to write %s"), get_index_file());
695 rollback_lock_file(&lock);
696 return clean ? 0 : 1;
697 } else {
698 return try_merge_command(strategy, xopts_nr, xopts,
699 common, head_arg, remoteheads);
700 }
701 }
702
703 static void count_diff_files(struct diff_queue_struct *q,
704 struct diff_options *opt, void *data)
705 {
706 int *count = data;
707
708 (*count) += q->nr;
709 }
710
711 static int count_unmerged_entries(void)
712 {
713 int i, ret = 0;
714
715 for (i = 0; i < active_nr; i++)
716 if (ce_stage(active_cache[i]))
717 ret++;
718
719 return ret;
720 }
721
722 static void add_strategies(const char *string, unsigned attr)
723 {
724 int i;
725
726 if (string) {
727 struct string_list list = STRING_LIST_INIT_DUP;
728 struct string_list_item *item;
729 string_list_split(&list, string, ' ', -1);
730 for_each_string_list_item(item, &list)
731 append_strategy(get_strategy(item->string));
732 string_list_clear(&list, 0);
733 return;
734 }
735 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
736 if (all_strategy[i].attr & attr)
737 append_strategy(&all_strategy[i]);
738
739 }
740
741 static void read_merge_msg(struct strbuf *msg)
742 {
743 const char *filename = git_path_merge_msg();
744 strbuf_reset(msg);
745 if (strbuf_read_file(msg, filename, 0) < 0)
746 die_errno(_("Could not read from '%s'"), filename);
747 }
748
749 static void write_merge_state(struct commit_list *);
750 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
751 {
752 if (err_msg)
753 error("%s", err_msg);
754 fprintf(stderr,
755 _("Not committing merge; use 'git commit' to complete the merge.\n"));
756 write_merge_state(remoteheads);
757 exit(1);
758 }
759
760 static const char merge_editor_comment[] =
761 N_("Please enter a commit message to explain why this merge is necessary,\n"
762 "especially if it merges an updated upstream into a topic branch.\n"
763 "\n"
764 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
765 "the commit.\n");
766
767 static void write_merge_heads(struct commit_list *);
768 static void prepare_to_commit(struct commit_list *remoteheads)
769 {
770 struct strbuf msg = STRBUF_INIT;
771 strbuf_addbuf(&msg, &merge_msg);
772 strbuf_addch(&msg, '\n');
773 if (squash)
774 BUG("the control must not reach here under --squash");
775 if (0 < option_edit)
776 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
777 if (signoff)
778 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
779 write_merge_heads(remoteheads);
780 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
781 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
782 git_path_merge_msg(), "merge", NULL))
783 abort_commit(remoteheads, NULL);
784 if (0 < option_edit) {
785 if (launch_editor(git_path_merge_msg(), NULL, NULL))
786 abort_commit(remoteheads, NULL);
787 }
788
789 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
790 "commit-msg",
791 git_path_merge_msg(), NULL))
792 abort_commit(remoteheads, NULL);
793
794 read_merge_msg(&msg);
795 strbuf_stripspace(&msg, 0 < option_edit);
796 if (!msg.len)
797 abort_commit(remoteheads, _("Empty commit message."));
798 strbuf_release(&merge_msg);
799 strbuf_addbuf(&merge_msg, &msg);
800 strbuf_release(&msg);
801 }
802
803 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
804 {
805 struct object_id result_tree, result_commit;
806 struct commit_list *parents, **pptr = &parents;
807 static struct lock_file lock;
808
809 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
810 refresh_cache(REFRESH_QUIET);
811 if (active_cache_changed &&
812 write_locked_index(&the_index, &lock, COMMIT_LOCK))
813 return error(_("Unable to write index."));
814 rollback_lock_file(&lock);
815
816 write_tree_trivial(&result_tree);
817 printf(_("Wonderful.\n"));
818 pptr = commit_list_append(head, pptr);
819 pptr = commit_list_append(remoteheads->item, pptr);
820 prepare_to_commit(remoteheads);
821 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
822 result_commit.hash, NULL, sign_commit))
823 die(_("failed to write commit object"));
824 finish(head, remoteheads, &result_commit, "In-index merge");
825 drop_save();
826 return 0;
827 }
828
829 static int finish_automerge(struct commit *head,
830 int head_subsumed,
831 struct commit_list *common,
832 struct commit_list *remoteheads,
833 struct object_id *result_tree,
834 const char *wt_strategy)
835 {
836 struct commit_list *parents = NULL;
837 struct strbuf buf = STRBUF_INIT;
838 struct object_id result_commit;
839
840 free_commit_list(common);
841 parents = remoteheads;
842 if (!head_subsumed || fast_forward == FF_NO)
843 commit_list_insert(head, &parents);
844 strbuf_addch(&merge_msg, '\n');
845 prepare_to_commit(remoteheads);
846 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
847 result_commit.hash, NULL, sign_commit))
848 die(_("failed to write commit object"));
849 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
850 finish(head, remoteheads, &result_commit, buf.buf);
851 strbuf_release(&buf);
852 drop_save();
853 return 0;
854 }
855
856 static int suggest_conflicts(void)
857 {
858 const char *filename;
859 FILE *fp;
860 struct strbuf msgbuf = STRBUF_INIT;
861
862 filename = git_path_merge_msg();
863 fp = xfopen(filename, "a");
864
865 append_conflicts_hint(&msgbuf);
866 fputs(msgbuf.buf, fp);
867 strbuf_release(&msgbuf);
868 fclose(fp);
869 rerere(allow_rerere_auto);
870 printf(_("Automatic merge failed; "
871 "fix conflicts and then commit the result.\n"));
872 return 1;
873 }
874
875 static int evaluate_result(void)
876 {
877 int cnt = 0;
878 struct rev_info rev;
879
880 /* Check how many files differ. */
881 init_revisions(&rev, "");
882 setup_revisions(0, NULL, &rev, NULL);
883 rev.diffopt.output_format |=
884 DIFF_FORMAT_CALLBACK;
885 rev.diffopt.format_callback = count_diff_files;
886 rev.diffopt.format_callback_data = &cnt;
887 run_diff_files(&rev, 0);
888
889 /*
890 * Check how many unmerged entries are
891 * there.
892 */
893 cnt += count_unmerged_entries();
894
895 return cnt;
896 }
897
898 /*
899 * Pretend as if the user told us to merge with the remote-tracking
900 * branch we have for the upstream of the current branch
901 */
902 static int setup_with_upstream(const char ***argv)
903 {
904 struct branch *branch = branch_get(NULL);
905 int i;
906 const char **args;
907
908 if (!branch)
909 die(_("No current branch."));
910 if (!branch->remote_name)
911 die(_("No remote for the current branch."));
912 if (!branch->merge_nr)
913 die(_("No default upstream defined for the current branch."));
914
915 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
916 for (i = 0; i < branch->merge_nr; i++) {
917 if (!branch->merge[i]->dst)
918 die(_("No remote-tracking branch for %s from %s"),
919 branch->merge[i]->src, branch->remote_name);
920 args[i] = branch->merge[i]->dst;
921 }
922 args[i] = NULL;
923 *argv = args;
924 return i;
925 }
926
927 static void write_merge_heads(struct commit_list *remoteheads)
928 {
929 struct commit_list *j;
930 struct strbuf buf = STRBUF_INIT;
931
932 for (j = remoteheads; j; j = j->next) {
933 struct object_id *oid;
934 struct commit *c = j->item;
935 if (c->util && merge_remote_util(c)->obj) {
936 oid = &merge_remote_util(c)->obj->oid;
937 } else {
938 oid = &c->object.oid;
939 }
940 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
941 }
942 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
943
944 strbuf_reset(&buf);
945 if (fast_forward == FF_NO)
946 strbuf_addstr(&buf, "no-ff");
947 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
948 strbuf_release(&buf);
949 }
950
951 static void write_merge_state(struct commit_list *remoteheads)
952 {
953 write_merge_heads(remoteheads);
954 strbuf_addch(&merge_msg, '\n');
955 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
956 }
957
958 static int default_edit_option(void)
959 {
960 static const char name[] = "GIT_MERGE_AUTOEDIT";
961 const char *e = getenv(name);
962 struct stat st_stdin, st_stdout;
963
964 if (have_message)
965 /* an explicit -m msg without --[no-]edit */
966 return 0;
967
968 if (e) {
969 int v = git_parse_maybe_bool(e);
970 if (v < 0)
971 die(_("Bad value '%s' in environment '%s'"), e, name);
972 return v;
973 }
974
975 /* Use editor if stdin and stdout are the same and is a tty */
976 return (!fstat(0, &st_stdin) &&
977 !fstat(1, &st_stdout) &&
978 isatty(0) && isatty(1) &&
979 st_stdin.st_dev == st_stdout.st_dev &&
980 st_stdin.st_ino == st_stdout.st_ino &&
981 st_stdin.st_mode == st_stdout.st_mode);
982 }
983
984 static struct commit_list *reduce_parents(struct commit *head_commit,
985 int *head_subsumed,
986 struct commit_list *remoteheads)
987 {
988 struct commit_list *parents, **remotes;
989
990 /*
991 * Is the current HEAD reachable from another commit being
992 * merged? If so we do not want to record it as a parent of
993 * the resulting merge, unless --no-ff is given. We will flip
994 * this variable to 0 when we find HEAD among the independent
995 * tips being merged.
996 */
997 *head_subsumed = 1;
998
999 /* Find what parents to record by checking independent ones. */
1000 parents = reduce_heads(remoteheads);
1001 free_commit_list(remoteheads);
1002
1003 remoteheads = NULL;
1004 remotes = &remoteheads;
1005 while (parents) {
1006 struct commit *commit = pop_commit(&parents);
1007 if (commit == head_commit)
1008 *head_subsumed = 0;
1009 else
1010 remotes = &commit_list_insert(commit, remotes)->next;
1011 }
1012 return remoteheads;
1013 }
1014
1015 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1016 {
1017 struct fmt_merge_msg_opts opts;
1018
1019 memset(&opts, 0, sizeof(opts));
1020 opts.add_title = !have_message;
1021 opts.shortlog_len = shortlog_len;
1022 opts.credit_people = (0 < option_edit);
1023
1024 fmt_merge_msg(merge_names, merge_msg, &opts);
1025 if (merge_msg->len)
1026 strbuf_setlen(merge_msg, merge_msg->len - 1);
1027 }
1028
1029 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1030 {
1031 const char *filename;
1032 int fd, pos, npos;
1033 struct strbuf fetch_head_file = STRBUF_INIT;
1034
1035 if (!merge_names)
1036 merge_names = &fetch_head_file;
1037
1038 filename = git_path_fetch_head();
1039 fd = open(filename, O_RDONLY);
1040 if (fd < 0)
1041 die_errno(_("could not open '%s' for reading"), filename);
1042
1043 if (strbuf_read(merge_names, fd, 0) < 0)
1044 die_errno(_("could not read '%s'"), filename);
1045 if (close(fd) < 0)
1046 die_errno(_("could not close '%s'"), filename);
1047
1048 for (pos = 0; pos < merge_names->len; pos = npos) {
1049 struct object_id oid;
1050 char *ptr;
1051 struct commit *commit;
1052
1053 ptr = strchr(merge_names->buf + pos, '\n');
1054 if (ptr)
1055 npos = ptr - merge_names->buf + 1;
1056 else
1057 npos = merge_names->len;
1058
1059 if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
1060 get_oid_hex(merge_names->buf + pos, &oid))
1061 commit = NULL; /* bad */
1062 else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
1063 continue; /* not-for-merge */
1064 else {
1065 char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
1066 merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
1067 commit = get_merge_parent(merge_names->buf + pos);
1068 merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
1069 }
1070 if (!commit) {
1071 if (ptr)
1072 *ptr = '\0';
1073 die(_("not something we can merge in %s: %s"),
1074 filename, merge_names->buf + pos);
1075 }
1076 remotes = &commit_list_insert(commit, remotes)->next;
1077 }
1078
1079 if (merge_names == &fetch_head_file)
1080 strbuf_release(&fetch_head_file);
1081 }
1082
1083 static struct commit_list *collect_parents(struct commit *head_commit,
1084 int *head_subsumed,
1085 int argc, const char **argv,
1086 struct strbuf *merge_msg)
1087 {
1088 int i;
1089 struct commit_list *remoteheads = NULL;
1090 struct commit_list **remotes = &remoteheads;
1091 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1092
1093 if (merge_msg && (!have_message || shortlog_len))
1094 autogen = &merge_names;
1095
1096 if (head_commit)
1097 remotes = &commit_list_insert(head_commit, remotes)->next;
1098
1099 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1100 handle_fetch_head(remotes, autogen);
1101 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1102 } else {
1103 for (i = 0; i < argc; i++) {
1104 struct commit *commit = get_merge_parent(argv[i]);
1105 if (!commit)
1106 help_unknown_ref(argv[i], "merge",
1107 _("not something we can merge"));
1108 remotes = &commit_list_insert(commit, remotes)->next;
1109 }
1110 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1111 if (autogen) {
1112 struct commit_list *p;
1113 for (p = remoteheads; p; p = p->next)
1114 merge_name(merge_remote_util(p->item)->name, autogen);
1115 }
1116 }
1117
1118 if (autogen) {
1119 prepare_merge_message(autogen, merge_msg);
1120 strbuf_release(autogen);
1121 }
1122
1123 return remoteheads;
1124 }
1125
1126 int cmd_merge(int argc, const char **argv, const char *prefix)
1127 {
1128 struct object_id result_tree, stash, head_oid;
1129 struct commit *head_commit;
1130 struct strbuf buf = STRBUF_INIT;
1131 int i, ret = 0, head_subsumed;
1132 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1133 struct commit_list *common = NULL;
1134 const char *best_strategy = NULL, *wt_strategy = NULL;
1135 struct commit_list *remoteheads, *p;
1136 void *branch_to_free;
1137 int orig_argc = argc;
1138
1139 if (argc == 2 && !strcmp(argv[1], "-h"))
1140 usage_with_options(builtin_merge_usage, builtin_merge_options);
1141
1142 /*
1143 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1144 * current branch.
1145 */
1146 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1147 if (branch)
1148 skip_prefix(branch, "refs/heads/", &branch);
1149 if (!branch || is_null_oid(&head_oid))
1150 head_commit = NULL;
1151 else
1152 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1153
1154 init_diff_ui_defaults();
1155 git_config(git_merge_config, NULL);
1156
1157 if (branch_mergeoptions)
1158 parse_branch_merge_options(branch_mergeoptions);
1159 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1160 builtin_merge_usage, 0);
1161 if (shortlog_len < 0)
1162 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1163
1164 if (verbosity < 0 && show_progress == -1)
1165 show_progress = 0;
1166
1167 if (abort_current_merge) {
1168 int nargc = 2;
1169 const char *nargv[] = {"reset", "--merge", NULL};
1170
1171 if (orig_argc != 2)
1172 usage_msg_opt(_("--abort expects no arguments"),
1173 builtin_merge_usage, builtin_merge_options);
1174
1175 if (!file_exists(git_path_merge_head()))
1176 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1177
1178 /* Invoke 'git reset --merge' */
1179 ret = cmd_reset(nargc, nargv, prefix);
1180 goto done;
1181 }
1182
1183 if (continue_current_merge) {
1184 int nargc = 1;
1185 const char *nargv[] = {"commit", NULL};
1186
1187 if (orig_argc != 2)
1188 usage_msg_opt(_("--continue expects no arguments"),
1189 builtin_merge_usage, builtin_merge_options);
1190
1191 if (!file_exists(git_path_merge_head()))
1192 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1193
1194 /* Invoke 'git commit' */
1195 ret = cmd_commit(nargc, nargv, prefix);
1196 goto done;
1197 }
1198
1199 if (read_cache_unmerged())
1200 die_resolve_conflict("merge");
1201
1202 if (file_exists(git_path_merge_head())) {
1203 /*
1204 * There is no unmerged entry, don't advise 'git
1205 * add/rm <file>', just 'git commit'.
1206 */
1207 if (advice_resolve_conflict)
1208 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1209 "Please, commit your changes before you merge."));
1210 else
1211 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1212 }
1213 if (file_exists(git_path_cherry_pick_head())) {
1214 if (advice_resolve_conflict)
1215 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1216 "Please, commit your changes before you merge."));
1217 else
1218 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1219 }
1220 resolve_undo_clear();
1221
1222 if (verbosity < 0)
1223 show_diffstat = 0;
1224
1225 if (squash) {
1226 if (fast_forward == FF_NO)
1227 die(_("You cannot combine --squash with --no-ff."));
1228 option_commit = 0;
1229 }
1230
1231 if (!argc) {
1232 if (default_to_upstream)
1233 argc = setup_with_upstream(&argv);
1234 else
1235 die(_("No commit specified and merge.defaultToUpstream not set."));
1236 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1237 argv[0] = "@{-1}";
1238 }
1239
1240 if (!argc)
1241 usage_with_options(builtin_merge_usage,
1242 builtin_merge_options);
1243
1244 if (!head_commit) {
1245 /*
1246 * If the merged head is a valid one there is no reason
1247 * to forbid "git merge" into a branch yet to be born.
1248 * We do the same for "git pull".
1249 */
1250 struct object_id *remote_head_oid;
1251 if (squash)
1252 die(_("Squash commit into empty head not supported yet"));
1253 if (fast_forward == FF_NO)
1254 die(_("Non-fast-forward commit does not make sense into "
1255 "an empty head"));
1256 remoteheads = collect_parents(head_commit, &head_subsumed,
1257 argc, argv, NULL);
1258 if (!remoteheads)
1259 die(_("%s - not something we can merge"), argv[0]);
1260 if (remoteheads->next)
1261 die(_("Can merge only exactly one commit into empty head"));
1262 remote_head_oid = &remoteheads->item->object.oid;
1263 read_empty(remote_head_oid->hash, 0);
1264 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1265 UPDATE_REFS_DIE_ON_ERR);
1266 goto done;
1267 }
1268
1269 /*
1270 * All the rest are the commits being merged; prepare
1271 * the standard merge summary message to be appended
1272 * to the given message.
1273 */
1274 remoteheads = collect_parents(head_commit, &head_subsumed,
1275 argc, argv, &merge_msg);
1276
1277 if (!head_commit || !argc)
1278 usage_with_options(builtin_merge_usage,
1279 builtin_merge_options);
1280
1281 if (verify_signatures) {
1282 for (p = remoteheads; p; p = p->next) {
1283 struct commit *commit = p->item;
1284 char hex[GIT_MAX_HEXSZ + 1];
1285 struct signature_check signature_check;
1286 memset(&signature_check, 0, sizeof(signature_check));
1287
1288 check_commit_signature(commit, &signature_check);
1289
1290 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1291 switch (signature_check.result) {
1292 case 'G':
1293 break;
1294 case 'U':
1295 die(_("Commit %s has an untrusted GPG signature, "
1296 "allegedly by %s."), hex, signature_check.signer);
1297 case 'B':
1298 die(_("Commit %s has a bad GPG signature "
1299 "allegedly by %s."), hex, signature_check.signer);
1300 default: /* 'N' */
1301 die(_("Commit %s does not have a GPG signature."), hex);
1302 }
1303 if (verbosity >= 0 && signature_check.result == 'G')
1304 printf(_("Commit %s has a good GPG signature by %s\n"),
1305 hex, signature_check.signer);
1306
1307 signature_check_clear(&signature_check);
1308 }
1309 }
1310
1311 strbuf_addstr(&buf, "merge");
1312 for (p = remoteheads; p; p = p->next)
1313 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1314 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1315 strbuf_reset(&buf);
1316
1317 for (p = remoteheads; p; p = p->next) {
1318 struct commit *commit = p->item;
1319 strbuf_addf(&buf, "GITHEAD_%s",
1320 oid_to_hex(&commit->object.oid));
1321 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1322 strbuf_reset(&buf);
1323 if (fast_forward != FF_ONLY &&
1324 merge_remote_util(commit) &&
1325 merge_remote_util(commit)->obj &&
1326 merge_remote_util(commit)->obj->type == OBJ_TAG)
1327 fast_forward = FF_NO;
1328 }
1329
1330 if (option_edit < 0)
1331 option_edit = default_edit_option();
1332
1333 if (!use_strategies) {
1334 if (!remoteheads)
1335 ; /* already up-to-date */
1336 else if (!remoteheads->next)
1337 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1338 else
1339 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1340 }
1341
1342 for (i = 0; i < use_strategies_nr; i++) {
1343 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1344 fast_forward = FF_NO;
1345 if (use_strategies[i]->attr & NO_TRIVIAL)
1346 allow_trivial = 0;
1347 }
1348
1349 if (!remoteheads)
1350 ; /* already up-to-date */
1351 else if (!remoteheads->next)
1352 common = get_merge_bases(head_commit, remoteheads->item);
1353 else {
1354 struct commit_list *list = remoteheads;
1355 commit_list_insert(head_commit, &list);
1356 common = get_octopus_merge_bases(list);
1357 free(list);
1358 }
1359
1360 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1361 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1362
1363 if (remoteheads && !common) {
1364 /* No common ancestors found. */
1365 if (!allow_unrelated_histories)
1366 die(_("refusing to merge unrelated histories"));
1367 /* otherwise, we need a real merge. */
1368 } else if (!remoteheads ||
1369 (!remoteheads->next && !common->next &&
1370 common->item == remoteheads->item)) {
1371 /*
1372 * If head can reach all the merge then we are up to date.
1373 * but first the most common case of merging one remote.
1374 */
1375 finish_up_to_date(_("Already up to date."));
1376 goto done;
1377 } else if (fast_forward != FF_NO && !remoteheads->next &&
1378 !common->next &&
1379 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1380 /* Again the most common case of merging one remote. */
1381 struct strbuf msg = STRBUF_INIT;
1382 struct commit *commit;
1383
1384 if (verbosity >= 0) {
1385 printf(_("Updating %s..%s\n"),
1386 find_unique_abbrev(head_commit->object.oid.hash,
1387 DEFAULT_ABBREV),
1388 find_unique_abbrev(remoteheads->item->object.oid.hash,
1389 DEFAULT_ABBREV));
1390 }
1391 strbuf_addstr(&msg, "Fast-forward");
1392 if (have_message)
1393 strbuf_addstr(&msg,
1394 " (no commit created; -m option ignored)");
1395 commit = remoteheads->item;
1396 if (!commit) {
1397 ret = 1;
1398 goto done;
1399 }
1400
1401 if (checkout_fast_forward(&head_commit->object.oid,
1402 &commit->object.oid,
1403 overwrite_ignore)) {
1404 ret = 1;
1405 goto done;
1406 }
1407
1408 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1409 drop_save();
1410 goto done;
1411 } else if (!remoteheads->next && common->next)
1412 ;
1413 /*
1414 * We are not doing octopus and not fast-forward. Need
1415 * a real merge.
1416 */
1417 else if (!remoteheads->next && !common->next && option_commit) {
1418 /*
1419 * We are not doing octopus, not fast-forward, and have
1420 * only one common.
1421 */
1422 refresh_cache(REFRESH_QUIET);
1423 if (allow_trivial && fast_forward != FF_ONLY) {
1424 /* See if it is really trivial. */
1425 git_committer_info(IDENT_STRICT);
1426 printf(_("Trying really trivial in-index merge...\n"));
1427 if (!read_tree_trivial(&common->item->object.oid,
1428 &head_commit->object.oid,
1429 &remoteheads->item->object.oid)) {
1430 ret = merge_trivial(head_commit, remoteheads);
1431 goto done;
1432 }
1433 printf(_("Nope.\n"));
1434 }
1435 } else {
1436 /*
1437 * An octopus. If we can reach all the remote we are up
1438 * to date.
1439 */
1440 int up_to_date = 1;
1441 struct commit_list *j;
1442
1443 for (j = remoteheads; j; j = j->next) {
1444 struct commit_list *common_one;
1445
1446 /*
1447 * Here we *have* to calculate the individual
1448 * merge_bases again, otherwise "git merge HEAD^
1449 * HEAD^^" would be missed.
1450 */
1451 common_one = get_merge_bases(head_commit, j->item);
1452 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1453 up_to_date = 0;
1454 break;
1455 }
1456 }
1457 if (up_to_date) {
1458 finish_up_to_date(_("Already up to date. Yeeah!"));
1459 goto done;
1460 }
1461 }
1462
1463 if (fast_forward == FF_ONLY)
1464 die(_("Not possible to fast-forward, aborting."));
1465
1466 /* We are going to make a new commit. */
1467 git_committer_info(IDENT_STRICT);
1468
1469 /*
1470 * At this point, we need a real merge. No matter what strategy
1471 * we use, it would operate on the index, possibly affecting the
1472 * working tree, and when resolved cleanly, have the desired
1473 * tree in the index -- this means that the index must be in
1474 * sync with the head commit. The strategies are responsible
1475 * to ensure this.
1476 */
1477 if (use_strategies_nr == 1 ||
1478 /*
1479 * Stash away the local changes so that we can try more than one.
1480 */
1481 save_state(&stash))
1482 oidclr(&stash);
1483
1484 for (i = 0; i < use_strategies_nr; i++) {
1485 int ret;
1486 if (i) {
1487 printf(_("Rewinding the tree to pristine...\n"));
1488 restore_state(&head_commit->object.oid, &stash);
1489 }
1490 if (use_strategies_nr != 1)
1491 printf(_("Trying merge strategy %s...\n"),
1492 use_strategies[i]->name);
1493 /*
1494 * Remember which strategy left the state in the working
1495 * tree.
1496 */
1497 wt_strategy = use_strategies[i]->name;
1498
1499 ret = try_merge_strategy(use_strategies[i]->name,
1500 common, remoteheads,
1501 head_commit);
1502 if (!option_commit && !ret) {
1503 merge_was_ok = 1;
1504 /*
1505 * This is necessary here just to avoid writing
1506 * the tree, but later we will *not* exit with
1507 * status code 1 because merge_was_ok is set.
1508 */
1509 ret = 1;
1510 }
1511
1512 if (ret) {
1513 /*
1514 * The backend exits with 1 when conflicts are
1515 * left to be resolved, with 2 when it does not
1516 * handle the given merge at all.
1517 */
1518 if (ret == 1) {
1519 int cnt = evaluate_result();
1520
1521 if (best_cnt <= 0 || cnt <= best_cnt) {
1522 best_strategy = use_strategies[i]->name;
1523 best_cnt = cnt;
1524 }
1525 }
1526 if (merge_was_ok)
1527 break;
1528 else
1529 continue;
1530 }
1531
1532 /* Automerge succeeded. */
1533 write_tree_trivial(&result_tree);
1534 automerge_was_ok = 1;
1535 break;
1536 }
1537
1538 /*
1539 * If we have a resulting tree, that means the strategy module
1540 * auto resolved the merge cleanly.
1541 */
1542 if (automerge_was_ok) {
1543 ret = finish_automerge(head_commit, head_subsumed,
1544 common, remoteheads,
1545 &result_tree, wt_strategy);
1546 goto done;
1547 }
1548
1549 /*
1550 * Pick the result from the best strategy and have the user fix
1551 * it up.
1552 */
1553 if (!best_strategy) {
1554 restore_state(&head_commit->object.oid, &stash);
1555 if (use_strategies_nr > 1)
1556 fprintf(stderr,
1557 _("No merge strategy handled the merge.\n"));
1558 else
1559 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1560 use_strategies[0]->name);
1561 ret = 2;
1562 goto done;
1563 } else if (best_strategy == wt_strategy)
1564 ; /* We already have its result in the working tree. */
1565 else {
1566 printf(_("Rewinding the tree to pristine...\n"));
1567 restore_state(&head_commit->object.oid, &stash);
1568 printf(_("Using the %s to prepare resolving by hand.\n"),
1569 best_strategy);
1570 try_merge_strategy(best_strategy, common, remoteheads,
1571 head_commit);
1572 }
1573
1574 if (squash)
1575 finish(head_commit, remoteheads, NULL, NULL);
1576 else
1577 write_merge_state(remoteheads);
1578
1579 if (merge_was_ok)
1580 fprintf(stderr, _("Automatic merge went well; "
1581 "stopped before committing as requested\n"));
1582 else
1583 ret = suggest_conflicts();
1584
1585 done:
1586 free(branch_to_free);
1587 return ret;
1588 }