merge: convert checkout_fast_forward to struct object_id
[git/git.git] / builtin / merge.c
1 /*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
6 * Based on git-merge.sh by Junio C Hamano.
7 */
8
9 #include "cache.h"
10 #include "parse-options.h"
11 #include "builtin.h"
12 #include "lockfile.h"
13 #include "run-command.h"
14 #include "diff.h"
15 #include "refs.h"
16 #include "commit.h"
17 #include "diffcore.h"
18 #include "revision.h"
19 #include "unpack-trees.h"
20 #include "cache-tree.h"
21 #include "dir.h"
22 #include "utf8.h"
23 #include "log-tree.h"
24 #include "color.h"
25 #include "rerere.h"
26 #include "help.h"
27 #include "merge-recursive.h"
28 #include "resolve-undo.h"
29 #include "remote.h"
30 #include "fmt-merge-msg.h"
31 #include "gpg-interface.h"
32 #include "sequencer.h"
33 #include "string-list.h"
34
35 #define DEFAULT_TWOHEAD (1<<0)
36 #define DEFAULT_OCTOPUS (1<<1)
37 #define NO_FAST_FORWARD (1<<2)
38 #define NO_TRIVIAL (1<<3)
39
40 struct strategy {
41 const char *name;
42 unsigned attr;
43 };
44
45 static const char * const builtin_merge_usage[] = {
46 N_("git merge [<options>] [<commit>...]"),
47 N_("git merge --abort"),
48 N_("git merge --continue"),
49 NULL
50 };
51
52 static int show_diffstat = 1, shortlog_len = -1, squash;
53 static int option_commit = 1;
54 static int option_edit = -1;
55 static int allow_trivial = 1, have_message, verify_signatures;
56 static int overwrite_ignore = 1;
57 static struct strbuf merge_msg = STRBUF_INIT;
58 static struct strategy **use_strategies;
59 static size_t use_strategies_nr, use_strategies_alloc;
60 static const char **xopts;
61 static size_t xopts_nr, xopts_alloc;
62 static const char *branch;
63 static char *branch_mergeoptions;
64 static int option_renormalize;
65 static int verbosity;
66 static int allow_rerere_auto;
67 static int abort_current_merge;
68 static int continue_current_merge;
69 static int allow_unrelated_histories;
70 static int show_progress = -1;
71 static int default_to_upstream = 1;
72 static const char *sign_commit;
73
74 static struct strategy all_strategy[] = {
75 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
76 { "octopus", DEFAULT_OCTOPUS },
77 { "resolve", 0 },
78 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
79 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
80 };
81
82 static const char *pull_twohead, *pull_octopus;
83
84 enum ff_type {
85 FF_NO,
86 FF_ALLOW,
87 FF_ONLY
88 };
89
90 static enum ff_type fast_forward = FF_ALLOW;
91
92 static int option_parse_message(const struct option *opt,
93 const char *arg, int unset)
94 {
95 struct strbuf *buf = opt->value;
96
97 if (unset)
98 strbuf_setlen(buf, 0);
99 else if (arg) {
100 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
101 have_message = 1;
102 } else
103 return error(_("switch `m' requires a value"));
104 return 0;
105 }
106
107 static struct strategy *get_strategy(const char *name)
108 {
109 int i;
110 struct strategy *ret;
111 static struct cmdnames main_cmds, other_cmds;
112 static int loaded;
113
114 if (!name)
115 return NULL;
116
117 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
118 if (!strcmp(name, all_strategy[i].name))
119 return &all_strategy[i];
120
121 if (!loaded) {
122 struct cmdnames not_strategies;
123 loaded = 1;
124
125 memset(&not_strategies, 0, sizeof(struct cmdnames));
126 load_command_list("git-merge-", &main_cmds, &other_cmds);
127 for (i = 0; i < main_cmds.cnt; i++) {
128 int j, found = 0;
129 struct cmdname *ent = main_cmds.names[i];
130 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
131 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
132 && !all_strategy[j].name[ent->len])
133 found = 1;
134 if (!found)
135 add_cmdname(&not_strategies, ent->name, ent->len);
136 }
137 exclude_cmds(&main_cmds, &not_strategies);
138 }
139 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
140 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
141 fprintf(stderr, _("Available strategies are:"));
142 for (i = 0; i < main_cmds.cnt; i++)
143 fprintf(stderr, " %s", main_cmds.names[i]->name);
144 fprintf(stderr, ".\n");
145 if (other_cmds.cnt) {
146 fprintf(stderr, _("Available custom strategies are:"));
147 for (i = 0; i < other_cmds.cnt; i++)
148 fprintf(stderr, " %s", other_cmds.names[i]->name);
149 fprintf(stderr, ".\n");
150 }
151 exit(1);
152 }
153
154 ret = xcalloc(1, sizeof(struct strategy));
155 ret->name = xstrdup(name);
156 ret->attr = NO_TRIVIAL;
157 return ret;
158 }
159
160 static void append_strategy(struct strategy *s)
161 {
162 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
163 use_strategies[use_strategies_nr++] = s;
164 }
165
166 static int option_parse_strategy(const struct option *opt,
167 const char *name, int unset)
168 {
169 if (unset)
170 return 0;
171
172 append_strategy(get_strategy(name));
173 return 0;
174 }
175
176 static int option_parse_x(const struct option *opt,
177 const char *arg, int unset)
178 {
179 if (unset)
180 return 0;
181
182 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
183 xopts[xopts_nr++] = xstrdup(arg);
184 return 0;
185 }
186
187 static int option_parse_n(const struct option *opt,
188 const char *arg, int unset)
189 {
190 show_diffstat = unset;
191 return 0;
192 }
193
194 static struct option builtin_merge_options[] = {
195 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
196 N_("do not show a diffstat at the end of the merge"),
197 PARSE_OPT_NOARG, option_parse_n },
198 OPT_BOOL(0, "stat", &show_diffstat,
199 N_("show a diffstat at the end of the merge")),
200 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
201 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
202 N_("add (at most <n>) entries from shortlog to merge commit message"),
203 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
204 OPT_BOOL(0, "squash", &squash,
205 N_("create a single commit instead of doing a merge")),
206 OPT_BOOL(0, "commit", &option_commit,
207 N_("perform a commit if the merge succeeds (default)")),
208 OPT_BOOL('e', "edit", &option_edit,
209 N_("edit message before committing")),
210 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
211 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
212 N_("abort if fast-forward is not possible"),
213 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
214 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
215 OPT_BOOL(0, "verify-signatures", &verify_signatures,
216 N_("verify that the named commit has a valid GPG signature")),
217 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
218 N_("merge strategy to use"), option_parse_strategy),
219 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
220 N_("option for selected merge strategy"), option_parse_x),
221 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
222 N_("merge commit message (for a non-fast-forward merge)"),
223 option_parse_message),
224 OPT__VERBOSITY(&verbosity),
225 OPT_BOOL(0, "abort", &abort_current_merge,
226 N_("abort the current in-progress merge")),
227 OPT_BOOL(0, "continue", &continue_current_merge,
228 N_("continue the current in-progress merge")),
229 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
230 N_("allow merging unrelated histories")),
231 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
232 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
233 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
234 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
235 OPT_END()
236 };
237
238 /* Cleans up metadata that is uninteresting after a succeeded merge. */
239 static void drop_save(void)
240 {
241 unlink(git_path_merge_head());
242 unlink(git_path_merge_msg());
243 unlink(git_path_merge_mode());
244 }
245
246 static int save_state(struct object_id *stash)
247 {
248 int len;
249 struct child_process cp = CHILD_PROCESS_INIT;
250 struct strbuf buffer = STRBUF_INIT;
251 const char *argv[] = {"stash", "create", NULL};
252
253 cp.argv = argv;
254 cp.out = -1;
255 cp.git_cmd = 1;
256
257 if (start_command(&cp))
258 die(_("could not run stash."));
259 len = strbuf_read(&buffer, cp.out, 1024);
260 close(cp.out);
261
262 if (finish_command(&cp) || len < 0)
263 die(_("stash failed"));
264 else if (!len) /* no changes */
265 return -1;
266 strbuf_setlen(&buffer, buffer.len-1);
267 if (get_oid(buffer.buf, stash))
268 die(_("not a valid object: %s"), buffer.buf);
269 return 0;
270 }
271
272 static void read_empty(unsigned const char *sha1, int verbose)
273 {
274 int i = 0;
275 const char *args[7];
276
277 args[i++] = "read-tree";
278 if (verbose)
279 args[i++] = "-v";
280 args[i++] = "-m";
281 args[i++] = "-u";
282 args[i++] = EMPTY_TREE_SHA1_HEX;
283 args[i++] = sha1_to_hex(sha1);
284 args[i] = NULL;
285
286 if (run_command_v_opt(args, RUN_GIT_CMD))
287 die(_("read-tree failed"));
288 }
289
290 static void reset_hard(unsigned const char *sha1, int verbose)
291 {
292 int i = 0;
293 const char *args[6];
294
295 args[i++] = "read-tree";
296 if (verbose)
297 args[i++] = "-v";
298 args[i++] = "--reset";
299 args[i++] = "-u";
300 args[i++] = sha1_to_hex(sha1);
301 args[i] = NULL;
302
303 if (run_command_v_opt(args, RUN_GIT_CMD))
304 die(_("read-tree failed"));
305 }
306
307 static void restore_state(const struct object_id *head,
308 const struct object_id *stash)
309 {
310 struct strbuf sb = STRBUF_INIT;
311 const char *args[] = { "stash", "apply", NULL, NULL };
312
313 if (is_null_oid(stash))
314 return;
315
316 reset_hard(head->hash, 1);
317
318 args[2] = oid_to_hex(stash);
319
320 /*
321 * It is OK to ignore error here, for example when there was
322 * nothing to restore.
323 */
324 run_command_v_opt(args, RUN_GIT_CMD);
325
326 strbuf_release(&sb);
327 refresh_cache(REFRESH_QUIET);
328 }
329
330 /* This is called when no merge was necessary. */
331 static void finish_up_to_date(const char *msg)
332 {
333 if (verbosity >= 0)
334 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
335 drop_save();
336 }
337
338 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
339 {
340 struct rev_info rev;
341 struct strbuf out = STRBUF_INIT;
342 struct commit_list *j;
343 struct pretty_print_context ctx = {0};
344
345 printf(_("Squash commit -- not updating HEAD\n"));
346
347 init_revisions(&rev, NULL);
348 rev.ignore_merges = 1;
349 rev.commit_format = CMIT_FMT_MEDIUM;
350
351 commit->object.flags |= UNINTERESTING;
352 add_pending_object(&rev, &commit->object, NULL);
353
354 for (j = remoteheads; j; j = j->next)
355 add_pending_object(&rev, &j->item->object, NULL);
356
357 setup_revisions(0, NULL, &rev, NULL);
358 if (prepare_revision_walk(&rev))
359 die(_("revision walk setup failed"));
360
361 ctx.abbrev = rev.abbrev;
362 ctx.date_mode = rev.date_mode;
363 ctx.fmt = rev.commit_format;
364
365 strbuf_addstr(&out, "Squashed commit of the following:\n");
366 while ((commit = get_revision(&rev)) != NULL) {
367 strbuf_addch(&out, '\n');
368 strbuf_addf(&out, "commit %s\n",
369 oid_to_hex(&commit->object.oid));
370 pretty_print_commit(&ctx, commit, &out);
371 }
372 write_file_buf(git_path_squash_msg(), out.buf, out.len);
373 strbuf_release(&out);
374 }
375
376 static void finish(struct commit *head_commit,
377 struct commit_list *remoteheads,
378 const struct object_id *new_head, const char *msg)
379 {
380 struct strbuf reflog_message = STRBUF_INIT;
381 const struct object_id *head = &head_commit->object.oid;
382
383 if (!msg)
384 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
385 else {
386 if (verbosity >= 0)
387 printf("%s\n", msg);
388 strbuf_addf(&reflog_message, "%s: %s",
389 getenv("GIT_REFLOG_ACTION"), msg);
390 }
391 if (squash) {
392 squash_message(head_commit, remoteheads);
393 } else {
394 if (verbosity >= 0 && !merge_msg.len)
395 printf(_("No merge message -- not updating HEAD\n"));
396 else {
397 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
398 update_ref(reflog_message.buf, "HEAD",
399 new_head->hash, head->hash, 0,
400 UPDATE_REFS_DIE_ON_ERR);
401 /*
402 * We ignore errors in 'gc --auto', since the
403 * user should see them.
404 */
405 close_all_packs();
406 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
407 }
408 }
409 if (new_head && show_diffstat) {
410 struct diff_options opts;
411 diff_setup(&opts);
412 opts.stat_width = -1; /* use full terminal width */
413 opts.stat_graph_width = -1; /* respect statGraphWidth config */
414 opts.output_format |=
415 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
416 opts.detect_rename = DIFF_DETECT_RENAME;
417 diff_setup_done(&opts);
418 diff_tree_sha1(head->hash, new_head->hash, "", &opts);
419 diffcore_std(&opts);
420 diff_flush(&opts);
421 }
422
423 /* Run a post-merge hook */
424 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
425
426 strbuf_release(&reflog_message);
427 }
428
429 /* Get the name for the merge commit's message. */
430 static void merge_name(const char *remote, struct strbuf *msg)
431 {
432 struct commit *remote_head;
433 struct object_id branch_head;
434 struct strbuf buf = STRBUF_INIT;
435 struct strbuf bname = STRBUF_INIT;
436 const char *ptr;
437 char *found_ref;
438 int len, early;
439
440 strbuf_branchname(&bname, remote, 0);
441 remote = bname.buf;
442
443 oidclr(&branch_head);
444 remote_head = get_merge_parent(remote);
445 if (!remote_head)
446 die(_("'%s' does not point to a commit"), remote);
447
448 if (dwim_ref(remote, strlen(remote), branch_head.hash, &found_ref) > 0) {
449 if (starts_with(found_ref, "refs/heads/")) {
450 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
451 oid_to_hex(&branch_head), remote);
452 goto cleanup;
453 }
454 if (starts_with(found_ref, "refs/tags/")) {
455 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
456 oid_to_hex(&branch_head), remote);
457 goto cleanup;
458 }
459 if (starts_with(found_ref, "refs/remotes/")) {
460 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
461 oid_to_hex(&branch_head), remote);
462 goto cleanup;
463 }
464 }
465
466 /* See if remote matches <name>^^^.. or <name>~<number> */
467 for (len = 0, ptr = remote + strlen(remote);
468 remote < ptr && ptr[-1] == '^';
469 ptr--)
470 len++;
471 if (len)
472 early = 1;
473 else {
474 early = 0;
475 ptr = strrchr(remote, '~');
476 if (ptr) {
477 int seen_nonzero = 0;
478
479 len++; /* count ~ */
480 while (*++ptr && isdigit(*ptr)) {
481 seen_nonzero |= (*ptr != '0');
482 len++;
483 }
484 if (*ptr)
485 len = 0; /* not ...~<number> */
486 else if (seen_nonzero)
487 early = 1;
488 else if (len == 1)
489 early = 1; /* "name~" is "name~1"! */
490 }
491 }
492 if (len) {
493 struct strbuf truname = STRBUF_INIT;
494 strbuf_addf(&truname, "refs/heads/%s", remote);
495 strbuf_setlen(&truname, truname.len - len);
496 if (ref_exists(truname.buf)) {
497 strbuf_addf(msg,
498 "%s\t\tbranch '%s'%s of .\n",
499 oid_to_hex(&remote_head->object.oid),
500 truname.buf + 11,
501 (early ? " (early part)" : ""));
502 strbuf_release(&truname);
503 goto cleanup;
504 }
505 strbuf_release(&truname);
506 }
507
508 if (remote_head->util) {
509 struct merge_remote_desc *desc;
510 desc = merge_remote_util(remote_head);
511 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
512 strbuf_addf(msg, "%s\t\t%s '%s'\n",
513 oid_to_hex(&desc->obj->oid),
514 typename(desc->obj->type),
515 remote);
516 goto cleanup;
517 }
518 }
519
520 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
521 oid_to_hex(&remote_head->object.oid), remote);
522 cleanup:
523 strbuf_release(&buf);
524 strbuf_release(&bname);
525 }
526
527 static void parse_branch_merge_options(char *bmo)
528 {
529 const char **argv;
530 int argc;
531
532 if (!bmo)
533 return;
534 argc = split_cmdline(bmo, &argv);
535 if (argc < 0)
536 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
537 split_cmdline_strerror(argc));
538 REALLOC_ARRAY(argv, argc + 2);
539 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
540 argc++;
541 argv[0] = "branch.*.mergeoptions";
542 parse_options(argc, argv, NULL, builtin_merge_options,
543 builtin_merge_usage, 0);
544 free(argv);
545 }
546
547 static int git_merge_config(const char *k, const char *v, void *cb)
548 {
549 int status;
550
551 if (branch && starts_with(k, "branch.") &&
552 starts_with(k + 7, branch) &&
553 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
554 free(branch_mergeoptions);
555 branch_mergeoptions = xstrdup(v);
556 return 0;
557 }
558
559 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
560 show_diffstat = git_config_bool(k, v);
561 else if (!strcmp(k, "pull.twohead"))
562 return git_config_string(&pull_twohead, k, v);
563 else if (!strcmp(k, "pull.octopus"))
564 return git_config_string(&pull_octopus, k, v);
565 else if (!strcmp(k, "merge.renormalize"))
566 option_renormalize = git_config_bool(k, v);
567 else if (!strcmp(k, "merge.ff")) {
568 int boolval = git_config_maybe_bool(k, v);
569 if (0 <= boolval) {
570 fast_forward = boolval ? FF_ALLOW : FF_NO;
571 } else if (v && !strcmp(v, "only")) {
572 fast_forward = FF_ONLY;
573 } /* do not barf on values from future versions of git */
574 return 0;
575 } else if (!strcmp(k, "merge.defaulttoupstream")) {
576 default_to_upstream = git_config_bool(k, v);
577 return 0;
578 } else if (!strcmp(k, "commit.gpgsign")) {
579 sign_commit = git_config_bool(k, v) ? "" : NULL;
580 return 0;
581 }
582
583 status = fmt_merge_msg_config(k, v, cb);
584 if (status)
585 return status;
586 status = git_gpg_config(k, v, NULL);
587 if (status)
588 return status;
589 return git_diff_ui_config(k, v, cb);
590 }
591
592 static int read_tree_trivial(struct object_id *common, struct object_id *head,
593 struct object_id *one)
594 {
595 int i, nr_trees = 0;
596 struct tree *trees[MAX_UNPACK_TREES];
597 struct tree_desc t[MAX_UNPACK_TREES];
598 struct unpack_trees_options opts;
599
600 memset(&opts, 0, sizeof(opts));
601 opts.head_idx = 2;
602 opts.src_index = &the_index;
603 opts.dst_index = &the_index;
604 opts.update = 1;
605 opts.verbose_update = 1;
606 opts.trivial_merges_only = 1;
607 opts.merge = 1;
608 trees[nr_trees] = parse_tree_indirect(common->hash);
609 if (!trees[nr_trees++])
610 return -1;
611 trees[nr_trees] = parse_tree_indirect(head->hash);
612 if (!trees[nr_trees++])
613 return -1;
614 trees[nr_trees] = parse_tree_indirect(one->hash);
615 if (!trees[nr_trees++])
616 return -1;
617 opts.fn = threeway_merge;
618 cache_tree_free(&active_cache_tree);
619 for (i = 0; i < nr_trees; i++) {
620 parse_tree(trees[i]);
621 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
622 }
623 if (unpack_trees(nr_trees, t, &opts))
624 return -1;
625 return 0;
626 }
627
628 static void write_tree_trivial(struct object_id *oid)
629 {
630 if (write_cache_as_tree(oid->hash, 0, NULL))
631 die(_("git write-tree failed to write a tree"));
632 }
633
634 static int try_merge_strategy(const char *strategy, struct commit_list *common,
635 struct commit_list *remoteheads,
636 struct commit *head)
637 {
638 static struct lock_file lock;
639 const char *head_arg = "HEAD";
640
641 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
642 refresh_cache(REFRESH_QUIET);
643 if (active_cache_changed &&
644 write_locked_index(&the_index, &lock, COMMIT_LOCK))
645 return error(_("Unable to write index."));
646 rollback_lock_file(&lock);
647
648 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
649 int clean, x;
650 struct commit *result;
651 struct commit_list *reversed = NULL;
652 struct merge_options o;
653 struct commit_list *j;
654
655 if (remoteheads->next) {
656 error(_("Not handling anything other than two heads merge."));
657 return 2;
658 }
659
660 init_merge_options(&o);
661 if (!strcmp(strategy, "subtree"))
662 o.subtree_shift = "";
663
664 o.renormalize = option_renormalize;
665 o.show_rename_progress =
666 show_progress == -1 ? isatty(2) : show_progress;
667
668 for (x = 0; x < xopts_nr; x++)
669 if (parse_merge_opt(&o, xopts[x]))
670 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
671
672 o.branch1 = head_arg;
673 o.branch2 = merge_remote_util(remoteheads->item)->name;
674
675 for (j = common; j; j = j->next)
676 commit_list_insert(j->item, &reversed);
677
678 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
679 clean = merge_recursive(&o, head,
680 remoteheads->item, reversed, &result);
681 if (clean < 0)
682 exit(128);
683 if (active_cache_changed &&
684 write_locked_index(&the_index, &lock, COMMIT_LOCK))
685 die (_("unable to write %s"), get_index_file());
686 rollback_lock_file(&lock);
687 return clean ? 0 : 1;
688 } else {
689 return try_merge_command(strategy, xopts_nr, xopts,
690 common, head_arg, remoteheads);
691 }
692 }
693
694 static void count_diff_files(struct diff_queue_struct *q,
695 struct diff_options *opt, void *data)
696 {
697 int *count = data;
698
699 (*count) += q->nr;
700 }
701
702 static int count_unmerged_entries(void)
703 {
704 int i, ret = 0;
705
706 for (i = 0; i < active_nr; i++)
707 if (ce_stage(active_cache[i]))
708 ret++;
709
710 return ret;
711 }
712
713 static void add_strategies(const char *string, unsigned attr)
714 {
715 int i;
716
717 if (string) {
718 struct string_list list = STRING_LIST_INIT_DUP;
719 struct string_list_item *item;
720 string_list_split(&list, string, ' ', -1);
721 for_each_string_list_item(item, &list)
722 append_strategy(get_strategy(item->string));
723 string_list_clear(&list, 0);
724 return;
725 }
726 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
727 if (all_strategy[i].attr & attr)
728 append_strategy(&all_strategy[i]);
729
730 }
731
732 static void read_merge_msg(struct strbuf *msg)
733 {
734 const char *filename = git_path_merge_msg();
735 strbuf_reset(msg);
736 if (strbuf_read_file(msg, filename, 0) < 0)
737 die_errno(_("Could not read from '%s'"), filename);
738 }
739
740 static void write_merge_state(struct commit_list *);
741 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
742 {
743 if (err_msg)
744 error("%s", err_msg);
745 fprintf(stderr,
746 _("Not committing merge; use 'git commit' to complete the merge.\n"));
747 write_merge_state(remoteheads);
748 exit(1);
749 }
750
751 static const char merge_editor_comment[] =
752 N_("Please enter a commit message to explain why this merge is necessary,\n"
753 "especially if it merges an updated upstream into a topic branch.\n"
754 "\n"
755 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
756 "the commit.\n");
757
758 static void prepare_to_commit(struct commit_list *remoteheads)
759 {
760 struct strbuf msg = STRBUF_INIT;
761 strbuf_addbuf(&msg, &merge_msg);
762 strbuf_addch(&msg, '\n');
763 if (0 < option_edit)
764 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
765 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
766 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
767 git_path_merge_msg(), "merge", NULL))
768 abort_commit(remoteheads, NULL);
769 if (0 < option_edit) {
770 if (launch_editor(git_path_merge_msg(), NULL, NULL))
771 abort_commit(remoteheads, NULL);
772 }
773 read_merge_msg(&msg);
774 strbuf_stripspace(&msg, 0 < option_edit);
775 if (!msg.len)
776 abort_commit(remoteheads, _("Empty commit message."));
777 strbuf_release(&merge_msg);
778 strbuf_addbuf(&merge_msg, &msg);
779 strbuf_release(&msg);
780 }
781
782 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
783 {
784 struct object_id result_tree, result_commit;
785 struct commit_list *parents, **pptr = &parents;
786 static struct lock_file lock;
787
788 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
789 refresh_cache(REFRESH_QUIET);
790 if (active_cache_changed &&
791 write_locked_index(&the_index, &lock, COMMIT_LOCK))
792 return error(_("Unable to write index."));
793 rollback_lock_file(&lock);
794
795 write_tree_trivial(&result_tree);
796 printf(_("Wonderful.\n"));
797 pptr = commit_list_append(head, pptr);
798 pptr = commit_list_append(remoteheads->item, pptr);
799 prepare_to_commit(remoteheads);
800 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree.hash, parents,
801 result_commit.hash, NULL, sign_commit))
802 die(_("failed to write commit object"));
803 finish(head, remoteheads, &result_commit, "In-index merge");
804 drop_save();
805 return 0;
806 }
807
808 static int finish_automerge(struct commit *head,
809 int head_subsumed,
810 struct commit_list *common,
811 struct commit_list *remoteheads,
812 struct object_id *result_tree,
813 const char *wt_strategy)
814 {
815 struct commit_list *parents = NULL;
816 struct strbuf buf = STRBUF_INIT;
817 struct object_id result_commit;
818
819 free_commit_list(common);
820 parents = remoteheads;
821 if (!head_subsumed || fast_forward == FF_NO)
822 commit_list_insert(head, &parents);
823 strbuf_addch(&merge_msg, '\n');
824 prepare_to_commit(remoteheads);
825 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree->hash, parents,
826 result_commit.hash, NULL, sign_commit))
827 die(_("failed to write commit object"));
828 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
829 finish(head, remoteheads, &result_commit, buf.buf);
830 strbuf_release(&buf);
831 drop_save();
832 return 0;
833 }
834
835 static int suggest_conflicts(void)
836 {
837 const char *filename;
838 FILE *fp;
839 struct strbuf msgbuf = STRBUF_INIT;
840
841 filename = git_path_merge_msg();
842 fp = fopen(filename, "a");
843 if (!fp)
844 die_errno(_("Could not open '%s' for writing"), filename);
845
846 append_conflicts_hint(&msgbuf);
847 fputs(msgbuf.buf, fp);
848 strbuf_release(&msgbuf);
849 fclose(fp);
850 rerere(allow_rerere_auto);
851 printf(_("Automatic merge failed; "
852 "fix conflicts and then commit the result.\n"));
853 return 1;
854 }
855
856 static int evaluate_result(void)
857 {
858 int cnt = 0;
859 struct rev_info rev;
860
861 /* Check how many files differ. */
862 init_revisions(&rev, "");
863 setup_revisions(0, NULL, &rev, NULL);
864 rev.diffopt.output_format |=
865 DIFF_FORMAT_CALLBACK;
866 rev.diffopt.format_callback = count_diff_files;
867 rev.diffopt.format_callback_data = &cnt;
868 run_diff_files(&rev, 0);
869
870 /*
871 * Check how many unmerged entries are
872 * there.
873 */
874 cnt += count_unmerged_entries();
875
876 return cnt;
877 }
878
879 /*
880 * Pretend as if the user told us to merge with the remote-tracking
881 * branch we have for the upstream of the current branch
882 */
883 static int setup_with_upstream(const char ***argv)
884 {
885 struct branch *branch = branch_get(NULL);
886 int i;
887 const char **args;
888
889 if (!branch)
890 die(_("No current branch."));
891 if (!branch->remote_name)
892 die(_("No remote for the current branch."));
893 if (!branch->merge_nr)
894 die(_("No default upstream defined for the current branch."));
895
896 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
897 for (i = 0; i < branch->merge_nr; i++) {
898 if (!branch->merge[i]->dst)
899 die(_("No remote-tracking branch for %s from %s"),
900 branch->merge[i]->src, branch->remote_name);
901 args[i] = branch->merge[i]->dst;
902 }
903 args[i] = NULL;
904 *argv = args;
905 return i;
906 }
907
908 static void write_merge_state(struct commit_list *remoteheads)
909 {
910 struct commit_list *j;
911 struct strbuf buf = STRBUF_INIT;
912
913 for (j = remoteheads; j; j = j->next) {
914 struct object_id *oid;
915 struct commit *c = j->item;
916 if (c->util && merge_remote_util(c)->obj) {
917 oid = &merge_remote_util(c)->obj->oid;
918 } else {
919 oid = &c->object.oid;
920 }
921 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
922 }
923 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
924 strbuf_addch(&merge_msg, '\n');
925 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
926
927 strbuf_reset(&buf);
928 if (fast_forward == FF_NO)
929 strbuf_addstr(&buf, "no-ff");
930 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
931 }
932
933 static int default_edit_option(void)
934 {
935 static const char name[] = "GIT_MERGE_AUTOEDIT";
936 const char *e = getenv(name);
937 struct stat st_stdin, st_stdout;
938
939 if (have_message)
940 /* an explicit -m msg without --[no-]edit */
941 return 0;
942
943 if (e) {
944 int v = git_config_maybe_bool(name, e);
945 if (v < 0)
946 die(_("Bad value '%s' in environment '%s'"), e, name);
947 return v;
948 }
949
950 /* Use editor if stdin and stdout are the same and is a tty */
951 return (!fstat(0, &st_stdin) &&
952 !fstat(1, &st_stdout) &&
953 isatty(0) && isatty(1) &&
954 st_stdin.st_dev == st_stdout.st_dev &&
955 st_stdin.st_ino == st_stdout.st_ino &&
956 st_stdin.st_mode == st_stdout.st_mode);
957 }
958
959 static struct commit_list *reduce_parents(struct commit *head_commit,
960 int *head_subsumed,
961 struct commit_list *remoteheads)
962 {
963 struct commit_list *parents, **remotes;
964
965 /*
966 * Is the current HEAD reachable from another commit being
967 * merged? If so we do not want to record it as a parent of
968 * the resulting merge, unless --no-ff is given. We will flip
969 * this variable to 0 when we find HEAD among the independent
970 * tips being merged.
971 */
972 *head_subsumed = 1;
973
974 /* Find what parents to record by checking independent ones. */
975 parents = reduce_heads(remoteheads);
976
977 remoteheads = NULL;
978 remotes = &remoteheads;
979 while (parents) {
980 struct commit *commit = pop_commit(&parents);
981 if (commit == head_commit)
982 *head_subsumed = 0;
983 else
984 remotes = &commit_list_insert(commit, remotes)->next;
985 }
986 return remoteheads;
987 }
988
989 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
990 {
991 struct fmt_merge_msg_opts opts;
992
993 memset(&opts, 0, sizeof(opts));
994 opts.add_title = !have_message;
995 opts.shortlog_len = shortlog_len;
996 opts.credit_people = (0 < option_edit);
997
998 fmt_merge_msg(merge_names, merge_msg, &opts);
999 if (merge_msg->len)
1000 strbuf_setlen(merge_msg, merge_msg->len - 1);
1001 }
1002
1003 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1004 {
1005 const char *filename;
1006 int fd, pos, npos;
1007 struct strbuf fetch_head_file = STRBUF_INIT;
1008
1009 if (!merge_names)
1010 merge_names = &fetch_head_file;
1011
1012 filename = git_path_fetch_head();
1013 fd = open(filename, O_RDONLY);
1014 if (fd < 0)
1015 die_errno(_("could not open '%s' for reading"), filename);
1016
1017 if (strbuf_read(merge_names, fd, 0) < 0)
1018 die_errno(_("could not read '%s'"), filename);
1019 if (close(fd) < 0)
1020 die_errno(_("could not close '%s'"), filename);
1021
1022 for (pos = 0; pos < merge_names->len; pos = npos) {
1023 struct object_id oid;
1024 char *ptr;
1025 struct commit *commit;
1026
1027 ptr = strchr(merge_names->buf + pos, '\n');
1028 if (ptr)
1029 npos = ptr - merge_names->buf + 1;
1030 else
1031 npos = merge_names->len;
1032
1033 if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
1034 get_oid_hex(merge_names->buf + pos, &oid))
1035 commit = NULL; /* bad */
1036 else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
1037 continue; /* not-for-merge */
1038 else {
1039 char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
1040 merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
1041 commit = get_merge_parent(merge_names->buf + pos);
1042 merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
1043 }
1044 if (!commit) {
1045 if (ptr)
1046 *ptr = '\0';
1047 die(_("not something we can merge in %s: %s"),
1048 filename, merge_names->buf + pos);
1049 }
1050 remotes = &commit_list_insert(commit, remotes)->next;
1051 }
1052
1053 if (merge_names == &fetch_head_file)
1054 strbuf_release(&fetch_head_file);
1055 }
1056
1057 static struct commit_list *collect_parents(struct commit *head_commit,
1058 int *head_subsumed,
1059 int argc, const char **argv,
1060 struct strbuf *merge_msg)
1061 {
1062 int i;
1063 struct commit_list *remoteheads = NULL;
1064 struct commit_list **remotes = &remoteheads;
1065 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1066
1067 if (merge_msg && (!have_message || shortlog_len))
1068 autogen = &merge_names;
1069
1070 if (head_commit)
1071 remotes = &commit_list_insert(head_commit, remotes)->next;
1072
1073 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1074 handle_fetch_head(remotes, autogen);
1075 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1076 } else {
1077 for (i = 0; i < argc; i++) {
1078 struct commit *commit = get_merge_parent(argv[i]);
1079 if (!commit)
1080 help_unknown_ref(argv[i], "merge",
1081 _("not something we can merge"));
1082 remotes = &commit_list_insert(commit, remotes)->next;
1083 }
1084 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1085 if (autogen) {
1086 struct commit_list *p;
1087 for (p = remoteheads; p; p = p->next)
1088 merge_name(merge_remote_util(p->item)->name, autogen);
1089 }
1090 }
1091
1092 if (autogen) {
1093 prepare_merge_message(autogen, merge_msg);
1094 strbuf_release(autogen);
1095 }
1096
1097 return remoteheads;
1098 }
1099
1100 int cmd_merge(int argc, const char **argv, const char *prefix)
1101 {
1102 struct object_id result_tree, stash, head_oid;
1103 struct commit *head_commit;
1104 struct strbuf buf = STRBUF_INIT;
1105 int i, ret = 0, head_subsumed;
1106 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1107 struct commit_list *common = NULL;
1108 const char *best_strategy = NULL, *wt_strategy = NULL;
1109 struct commit_list *remoteheads, *p;
1110 void *branch_to_free;
1111 int orig_argc = argc;
1112
1113 if (argc == 2 && !strcmp(argv[1], "-h"))
1114 usage_with_options(builtin_merge_usage, builtin_merge_options);
1115
1116 /*
1117 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1118 * current branch.
1119 */
1120 branch = branch_to_free = resolve_refdup("HEAD", 0, head_oid.hash, NULL);
1121 if (branch && starts_with(branch, "refs/heads/"))
1122 branch += 11;
1123 if (!branch || is_null_oid(&head_oid))
1124 head_commit = NULL;
1125 else
1126 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1127
1128 init_diff_ui_defaults();
1129 git_config(git_merge_config, NULL);
1130
1131 if (branch_mergeoptions)
1132 parse_branch_merge_options(branch_mergeoptions);
1133 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1134 builtin_merge_usage, 0);
1135 if (shortlog_len < 0)
1136 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1137
1138 if (verbosity < 0 && show_progress == -1)
1139 show_progress = 0;
1140
1141 if (abort_current_merge) {
1142 int nargc = 2;
1143 const char *nargv[] = {"reset", "--merge", NULL};
1144
1145 if (orig_argc != 2)
1146 usage_msg_opt(_("--abort expects no arguments"),
1147 builtin_merge_usage, builtin_merge_options);
1148
1149 if (!file_exists(git_path_merge_head()))
1150 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1151
1152 /* Invoke 'git reset --merge' */
1153 ret = cmd_reset(nargc, nargv, prefix);
1154 goto done;
1155 }
1156
1157 if (continue_current_merge) {
1158 int nargc = 1;
1159 const char *nargv[] = {"commit", NULL};
1160
1161 if (orig_argc != 2)
1162 usage_msg_opt(_("--continue expects no arguments"),
1163 builtin_merge_usage, builtin_merge_options);
1164
1165 if (!file_exists(git_path_merge_head()))
1166 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1167
1168 /* Invoke 'git commit' */
1169 ret = cmd_commit(nargc, nargv, prefix);
1170 goto done;
1171 }
1172
1173 if (read_cache_unmerged())
1174 die_resolve_conflict("merge");
1175
1176 if (file_exists(git_path_merge_head())) {
1177 /*
1178 * There is no unmerged entry, don't advise 'git
1179 * add/rm <file>', just 'git commit'.
1180 */
1181 if (advice_resolve_conflict)
1182 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1183 "Please, commit your changes before you merge."));
1184 else
1185 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1186 }
1187 if (file_exists(git_path_cherry_pick_head())) {
1188 if (advice_resolve_conflict)
1189 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1190 "Please, commit your changes before you merge."));
1191 else
1192 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1193 }
1194 resolve_undo_clear();
1195
1196 if (verbosity < 0)
1197 show_diffstat = 0;
1198
1199 if (squash) {
1200 if (fast_forward == FF_NO)
1201 die(_("You cannot combine --squash with --no-ff."));
1202 option_commit = 0;
1203 }
1204
1205 if (!argc) {
1206 if (default_to_upstream)
1207 argc = setup_with_upstream(&argv);
1208 else
1209 die(_("No commit specified and merge.defaultToUpstream not set."));
1210 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1211 argv[0] = "@{-1}";
1212 }
1213
1214 if (!argc)
1215 usage_with_options(builtin_merge_usage,
1216 builtin_merge_options);
1217
1218 if (!head_commit) {
1219 /*
1220 * If the merged head is a valid one there is no reason
1221 * to forbid "git merge" into a branch yet to be born.
1222 * We do the same for "git pull".
1223 */
1224 struct object_id *remote_head_oid;
1225 if (squash)
1226 die(_("Squash commit into empty head not supported yet"));
1227 if (fast_forward == FF_NO)
1228 die(_("Non-fast-forward commit does not make sense into "
1229 "an empty head"));
1230 remoteheads = collect_parents(head_commit, &head_subsumed,
1231 argc, argv, NULL);
1232 if (!remoteheads)
1233 die(_("%s - not something we can merge"), argv[0]);
1234 if (remoteheads->next)
1235 die(_("Can merge only exactly one commit into empty head"));
1236 remote_head_oid = &remoteheads->item->object.oid;
1237 read_empty(remote_head_oid->hash, 0);
1238 update_ref("initial pull", "HEAD", remote_head_oid->hash,
1239 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1240 goto done;
1241 }
1242
1243 /*
1244 * All the rest are the commits being merged; prepare
1245 * the standard merge summary message to be appended
1246 * to the given message.
1247 */
1248 remoteheads = collect_parents(head_commit, &head_subsumed,
1249 argc, argv, &merge_msg);
1250
1251 if (!head_commit || !argc)
1252 usage_with_options(builtin_merge_usage,
1253 builtin_merge_options);
1254
1255 if (verify_signatures) {
1256 for (p = remoteheads; p; p = p->next) {
1257 struct commit *commit = p->item;
1258 char hex[GIT_MAX_HEXSZ + 1];
1259 struct signature_check signature_check;
1260 memset(&signature_check, 0, sizeof(signature_check));
1261
1262 check_commit_signature(commit, &signature_check);
1263
1264 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1265 switch (signature_check.result) {
1266 case 'G':
1267 break;
1268 case 'U':
1269 die(_("Commit %s has an untrusted GPG signature, "
1270 "allegedly by %s."), hex, signature_check.signer);
1271 case 'B':
1272 die(_("Commit %s has a bad GPG signature "
1273 "allegedly by %s."), hex, signature_check.signer);
1274 default: /* 'N' */
1275 die(_("Commit %s does not have a GPG signature."), hex);
1276 }
1277 if (verbosity >= 0 && signature_check.result == 'G')
1278 printf(_("Commit %s has a good GPG signature by %s\n"),
1279 hex, signature_check.signer);
1280
1281 signature_check_clear(&signature_check);
1282 }
1283 }
1284
1285 strbuf_addstr(&buf, "merge");
1286 for (p = remoteheads; p; p = p->next)
1287 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1288 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1289 strbuf_reset(&buf);
1290
1291 for (p = remoteheads; p; p = p->next) {
1292 struct commit *commit = p->item;
1293 strbuf_addf(&buf, "GITHEAD_%s",
1294 oid_to_hex(&commit->object.oid));
1295 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1296 strbuf_reset(&buf);
1297 if (fast_forward != FF_ONLY &&
1298 merge_remote_util(commit) &&
1299 merge_remote_util(commit)->obj &&
1300 merge_remote_util(commit)->obj->type == OBJ_TAG)
1301 fast_forward = FF_NO;
1302 }
1303
1304 if (option_edit < 0)
1305 option_edit = default_edit_option();
1306
1307 if (!use_strategies) {
1308 if (!remoteheads)
1309 ; /* already up-to-date */
1310 else if (!remoteheads->next)
1311 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1312 else
1313 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1314 }
1315
1316 for (i = 0; i < use_strategies_nr; i++) {
1317 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1318 fast_forward = FF_NO;
1319 if (use_strategies[i]->attr & NO_TRIVIAL)
1320 allow_trivial = 0;
1321 }
1322
1323 if (!remoteheads)
1324 ; /* already up-to-date */
1325 else if (!remoteheads->next)
1326 common = get_merge_bases(head_commit, remoteheads->item);
1327 else {
1328 struct commit_list *list = remoteheads;
1329 commit_list_insert(head_commit, &list);
1330 common = get_octopus_merge_bases(list);
1331 free(list);
1332 }
1333
1334 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
1335 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1336
1337 if (remoteheads && !common) {
1338 /* No common ancestors found. */
1339 if (!allow_unrelated_histories)
1340 die(_("refusing to merge unrelated histories"));
1341 /* otherwise, we need a real merge. */
1342 } else if (!remoteheads ||
1343 (!remoteheads->next && !common->next &&
1344 common->item == remoteheads->item)) {
1345 /*
1346 * If head can reach all the merge then we are up to date.
1347 * but first the most common case of merging one remote.
1348 */
1349 finish_up_to_date(_("Already up-to-date."));
1350 goto done;
1351 } else if (fast_forward != FF_NO && !remoteheads->next &&
1352 !common->next &&
1353 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1354 /* Again the most common case of merging one remote. */
1355 struct strbuf msg = STRBUF_INIT;
1356 struct commit *commit;
1357
1358 if (verbosity >= 0) {
1359 printf(_("Updating %s..%s\n"),
1360 find_unique_abbrev(head_commit->object.oid.hash,
1361 DEFAULT_ABBREV),
1362 find_unique_abbrev(remoteheads->item->object.oid.hash,
1363 DEFAULT_ABBREV));
1364 }
1365 strbuf_addstr(&msg, "Fast-forward");
1366 if (have_message)
1367 strbuf_addstr(&msg,
1368 " (no commit created; -m option ignored)");
1369 commit = remoteheads->item;
1370 if (!commit) {
1371 ret = 1;
1372 goto done;
1373 }
1374
1375 if (checkout_fast_forward(&head_commit->object.oid,
1376 &commit->object.oid,
1377 overwrite_ignore)) {
1378 ret = 1;
1379 goto done;
1380 }
1381
1382 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1383 drop_save();
1384 goto done;
1385 } else if (!remoteheads->next && common->next)
1386 ;
1387 /*
1388 * We are not doing octopus and not fast-forward. Need
1389 * a real merge.
1390 */
1391 else if (!remoteheads->next && !common->next && option_commit) {
1392 /*
1393 * We are not doing octopus, not fast-forward, and have
1394 * only one common.
1395 */
1396 refresh_cache(REFRESH_QUIET);
1397 if (allow_trivial && fast_forward != FF_ONLY) {
1398 /* See if it is really trivial. */
1399 git_committer_info(IDENT_STRICT);
1400 printf(_("Trying really trivial in-index merge...\n"));
1401 if (!read_tree_trivial(&common->item->object.oid,
1402 &head_commit->object.oid,
1403 &remoteheads->item->object.oid)) {
1404 ret = merge_trivial(head_commit, remoteheads);
1405 goto done;
1406 }
1407 printf(_("Nope.\n"));
1408 }
1409 } else {
1410 /*
1411 * An octopus. If we can reach all the remote we are up
1412 * to date.
1413 */
1414 int up_to_date = 1;
1415 struct commit_list *j;
1416
1417 for (j = remoteheads; j; j = j->next) {
1418 struct commit_list *common_one;
1419
1420 /*
1421 * Here we *have* to calculate the individual
1422 * merge_bases again, otherwise "git merge HEAD^
1423 * HEAD^^" would be missed.
1424 */
1425 common_one = get_merge_bases(head_commit, j->item);
1426 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1427 up_to_date = 0;
1428 break;
1429 }
1430 }
1431 if (up_to_date) {
1432 finish_up_to_date(_("Already up-to-date. Yeeah!"));
1433 goto done;
1434 }
1435 }
1436
1437 if (fast_forward == FF_ONLY)
1438 die(_("Not possible to fast-forward, aborting."));
1439
1440 /* We are going to make a new commit. */
1441 git_committer_info(IDENT_STRICT);
1442
1443 /*
1444 * At this point, we need a real merge. No matter what strategy
1445 * we use, it would operate on the index, possibly affecting the
1446 * working tree, and when resolved cleanly, have the desired
1447 * tree in the index -- this means that the index must be in
1448 * sync with the head commit. The strategies are responsible
1449 * to ensure this.
1450 */
1451 if (use_strategies_nr == 1 ||
1452 /*
1453 * Stash away the local changes so that we can try more than one.
1454 */
1455 save_state(&stash))
1456 oidclr(&stash);
1457
1458 for (i = 0; i < use_strategies_nr; i++) {
1459 int ret;
1460 if (i) {
1461 printf(_("Rewinding the tree to pristine...\n"));
1462 restore_state(&head_commit->object.oid, &stash);
1463 }
1464 if (use_strategies_nr != 1)
1465 printf(_("Trying merge strategy %s...\n"),
1466 use_strategies[i]->name);
1467 /*
1468 * Remember which strategy left the state in the working
1469 * tree.
1470 */
1471 wt_strategy = use_strategies[i]->name;
1472
1473 ret = try_merge_strategy(use_strategies[i]->name,
1474 common, remoteheads,
1475 head_commit);
1476 if (!option_commit && !ret) {
1477 merge_was_ok = 1;
1478 /*
1479 * This is necessary here just to avoid writing
1480 * the tree, but later we will *not* exit with
1481 * status code 1 because merge_was_ok is set.
1482 */
1483 ret = 1;
1484 }
1485
1486 if (ret) {
1487 /*
1488 * The backend exits with 1 when conflicts are
1489 * left to be resolved, with 2 when it does not
1490 * handle the given merge at all.
1491 */
1492 if (ret == 1) {
1493 int cnt = evaluate_result();
1494
1495 if (best_cnt <= 0 || cnt <= best_cnt) {
1496 best_strategy = use_strategies[i]->name;
1497 best_cnt = cnt;
1498 }
1499 }
1500 if (merge_was_ok)
1501 break;
1502 else
1503 continue;
1504 }
1505
1506 /* Automerge succeeded. */
1507 write_tree_trivial(&result_tree);
1508 automerge_was_ok = 1;
1509 break;
1510 }
1511
1512 /*
1513 * If we have a resulting tree, that means the strategy module
1514 * auto resolved the merge cleanly.
1515 */
1516 if (automerge_was_ok) {
1517 ret = finish_automerge(head_commit, head_subsumed,
1518 common, remoteheads,
1519 &result_tree, wt_strategy);
1520 goto done;
1521 }
1522
1523 /*
1524 * Pick the result from the best strategy and have the user fix
1525 * it up.
1526 */
1527 if (!best_strategy) {
1528 restore_state(&head_commit->object.oid, &stash);
1529 if (use_strategies_nr > 1)
1530 fprintf(stderr,
1531 _("No merge strategy handled the merge.\n"));
1532 else
1533 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1534 use_strategies[0]->name);
1535 ret = 2;
1536 goto done;
1537 } else if (best_strategy == wt_strategy)
1538 ; /* We already have its result in the working tree. */
1539 else {
1540 printf(_("Rewinding the tree to pristine...\n"));
1541 restore_state(&head_commit->object.oid, &stash);
1542 printf(_("Using the %s to prepare resolving by hand.\n"),
1543 best_strategy);
1544 try_merge_strategy(best_strategy, common, remoteheads,
1545 head_commit);
1546 }
1547
1548 if (squash)
1549 finish(head_commit, remoteheads, NULL, NULL);
1550 else
1551 write_merge_state(remoteheads);
1552
1553 if (merge_was_ok)
1554 fprintf(stderr, _("Automatic merge went well; "
1555 "stopped before committing as requested\n"));
1556 else
1557 ret = suggest_conflicts();
1558
1559 done:
1560 free(branch_to_free);
1561 return ret;
1562 }