fetch-pack: write shallow, then check connectivity
[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 "refspec.h"
18 #include "commit.h"
19 #include "diffcore.h"
20 #include "revision.h"
21 #include "unpack-trees.h"
22 #include "cache-tree.h"
23 #include "dir.h"
24 #include "utf8.h"
25 #include "log-tree.h"
26 #include "color.h"
27 #include "rerere.h"
28 #include "help.h"
29 #include "merge-recursive.h"
30 #include "resolve-undo.h"
31 #include "remote.h"
32 #include "fmt-merge-msg.h"
33 #include "gpg-interface.h"
34 #include "sequencer.h"
35 #include "string-list.h"
36 #include "packfile.h"
37 #include "tag.h"
38 #include "alias.h"
39
40 #define DEFAULT_TWOHEAD (1<<0)
41 #define DEFAULT_OCTOPUS (1<<1)
42 #define NO_FAST_FORWARD (1<<2)
43 #define NO_TRIVIAL (1<<3)
44
45 struct strategy {
46 const char *name;
47 unsigned attr;
48 };
49
50 static const char * const builtin_merge_usage[] = {
51 N_("git merge [<options>] [<commit>...]"),
52 N_("git merge --abort"),
53 N_("git merge --continue"),
54 NULL
55 };
56
57 static int show_diffstat = 1, shortlog_len = -1, squash;
58 static int option_commit = 1;
59 static int option_edit = -1;
60 static int allow_trivial = 1, have_message, verify_signatures;
61 static int overwrite_ignore = 1;
62 static struct strbuf merge_msg = STRBUF_INIT;
63 static struct strategy **use_strategies;
64 static size_t use_strategies_nr, use_strategies_alloc;
65 static const char **xopts;
66 static size_t xopts_nr, xopts_alloc;
67 static const char *branch;
68 static char *branch_mergeoptions;
69 static int option_renormalize;
70 static int verbosity;
71 static int allow_rerere_auto;
72 static int abort_current_merge;
73 static int continue_current_merge;
74 static int allow_unrelated_histories;
75 static int show_progress = -1;
76 static int default_to_upstream = 1;
77 static int signoff;
78 static const char *sign_commit;
79 static int verify_msg = 1;
80
81 static struct strategy all_strategy[] = {
82 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
83 { "octopus", DEFAULT_OCTOPUS },
84 { "resolve", 0 },
85 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
86 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
87 };
88
89 static const char *pull_twohead, *pull_octopus;
90
91 enum ff_type {
92 FF_NO,
93 FF_ALLOW,
94 FF_ONLY
95 };
96
97 static enum ff_type fast_forward = FF_ALLOW;
98
99 static int option_parse_message(const struct option *opt,
100 const char *arg, int unset)
101 {
102 struct strbuf *buf = opt->value;
103
104 if (unset)
105 strbuf_setlen(buf, 0);
106 else if (arg) {
107 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
108 have_message = 1;
109 } else
110 return error(_("switch `m' requires a value"));
111 return 0;
112 }
113
114 static struct strategy *get_strategy(const char *name)
115 {
116 int i;
117 struct strategy *ret;
118 static struct cmdnames main_cmds, other_cmds;
119 static int loaded;
120
121 if (!name)
122 return NULL;
123
124 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
125 if (!strcmp(name, all_strategy[i].name))
126 return &all_strategy[i];
127
128 if (!loaded) {
129 struct cmdnames not_strategies;
130 loaded = 1;
131
132 memset(&not_strategies, 0, sizeof(struct cmdnames));
133 load_command_list("git-merge-", &main_cmds, &other_cmds);
134 for (i = 0; i < main_cmds.cnt; i++) {
135 int j, found = 0;
136 struct cmdname *ent = main_cmds.names[i];
137 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
138 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
139 && !all_strategy[j].name[ent->len])
140 found = 1;
141 if (!found)
142 add_cmdname(&not_strategies, ent->name, ent->len);
143 }
144 exclude_cmds(&main_cmds, &not_strategies);
145 }
146 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
147 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
148 fprintf(stderr, _("Available strategies are:"));
149 for (i = 0; i < main_cmds.cnt; i++)
150 fprintf(stderr, " %s", main_cmds.names[i]->name);
151 fprintf(stderr, ".\n");
152 if (other_cmds.cnt) {
153 fprintf(stderr, _("Available custom strategies are:"));
154 for (i = 0; i < other_cmds.cnt; i++)
155 fprintf(stderr, " %s", other_cmds.names[i]->name);
156 fprintf(stderr, ".\n");
157 }
158 exit(1);
159 }
160
161 ret = xcalloc(1, sizeof(struct strategy));
162 ret->name = xstrdup(name);
163 ret->attr = NO_TRIVIAL;
164 return ret;
165 }
166
167 static void append_strategy(struct strategy *s)
168 {
169 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
170 use_strategies[use_strategies_nr++] = s;
171 }
172
173 static int option_parse_strategy(const struct option *opt,
174 const char *name, int unset)
175 {
176 if (unset)
177 return 0;
178
179 append_strategy(get_strategy(name));
180 return 0;
181 }
182
183 static int option_parse_x(const struct option *opt,
184 const char *arg, int unset)
185 {
186 if (unset)
187 return 0;
188
189 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
190 xopts[xopts_nr++] = xstrdup(arg);
191 return 0;
192 }
193
194 static int option_parse_n(const struct option *opt,
195 const char *arg, int unset)
196 {
197 show_diffstat = unset;
198 return 0;
199 }
200
201 static struct option builtin_merge_options[] = {
202 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
203 N_("do not show a diffstat at the end of the merge"),
204 PARSE_OPT_NOARG, option_parse_n },
205 OPT_BOOL(0, "stat", &show_diffstat,
206 N_("show a diffstat at the end of the merge")),
207 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
208 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
209 N_("add (at most <n>) entries from shortlog to merge commit message"),
210 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
211 OPT_BOOL(0, "squash", &squash,
212 N_("create a single commit instead of doing a merge")),
213 OPT_BOOL(0, "commit", &option_commit,
214 N_("perform a commit if the merge succeeds (default)")),
215 OPT_BOOL('e', "edit", &option_edit,
216 N_("edit message before committing")),
217 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
218 OPT_SET_INT_F(0, "ff-only", &fast_forward,
219 N_("abort if fast-forward is not possible"),
220 FF_ONLY, PARSE_OPT_NONEG),
221 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
222 OPT_BOOL(0, "verify-signatures", &verify_signatures,
223 N_("verify that the named commit has a valid GPG signature")),
224 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
225 N_("merge strategy to use"), option_parse_strategy),
226 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
227 N_("option for selected merge strategy"), option_parse_x),
228 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
229 N_("merge commit message (for a non-fast-forward merge)"),
230 option_parse_message),
231 OPT__VERBOSITY(&verbosity),
232 OPT_BOOL(0, "abort", &abort_current_merge,
233 N_("abort the current in-progress merge")),
234 OPT_BOOL(0, "continue", &continue_current_merge,
235 N_("continue the current in-progress merge")),
236 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
237 N_("allow merging unrelated histories")),
238 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
239 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
240 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
241 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
242 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
243 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
244 OPT_END()
245 };
246
247 /* Cleans up metadata that is uninteresting after a succeeded merge. */
248 static void drop_save(void)
249 {
250 unlink(git_path_merge_head());
251 unlink(git_path_merge_msg());
252 unlink(git_path_merge_mode());
253 }
254
255 static int save_state(struct object_id *stash)
256 {
257 int len;
258 struct child_process cp = CHILD_PROCESS_INIT;
259 struct strbuf buffer = STRBUF_INIT;
260 const char *argv[] = {"stash", "create", NULL};
261 int rc = -1;
262
263 cp.argv = argv;
264 cp.out = -1;
265 cp.git_cmd = 1;
266
267 if (start_command(&cp))
268 die(_("could not run stash."));
269 len = strbuf_read(&buffer, cp.out, 1024);
270 close(cp.out);
271
272 if (finish_command(&cp) || len < 0)
273 die(_("stash failed"));
274 else if (!len) /* no changes */
275 goto out;
276 strbuf_setlen(&buffer, buffer.len-1);
277 if (get_oid(buffer.buf, stash))
278 die(_("not a valid object: %s"), buffer.buf);
279 rc = 0;
280 out:
281 strbuf_release(&buffer);
282 return rc;
283 }
284
285 static void read_empty(const struct object_id *oid, int verbose)
286 {
287 int i = 0;
288 const char *args[7];
289
290 args[i++] = "read-tree";
291 if (verbose)
292 args[i++] = "-v";
293 args[i++] = "-m";
294 args[i++] = "-u";
295 args[i++] = empty_tree_oid_hex();
296 args[i++] = oid_to_hex(oid);
297 args[i] = NULL;
298
299 if (run_command_v_opt(args, RUN_GIT_CMD))
300 die(_("read-tree failed"));
301 }
302
303 static void reset_hard(const struct object_id *oid, int verbose)
304 {
305 int i = 0;
306 const char *args[6];
307
308 args[i++] = "read-tree";
309 if (verbose)
310 args[i++] = "-v";
311 args[i++] = "--reset";
312 args[i++] = "-u";
313 args[i++] = oid_to_hex(oid);
314 args[i] = NULL;
315
316 if (run_command_v_opt(args, RUN_GIT_CMD))
317 die(_("read-tree failed"));
318 }
319
320 static void restore_state(const struct object_id *head,
321 const struct object_id *stash)
322 {
323 struct strbuf sb = STRBUF_INIT;
324 const char *args[] = { "stash", "apply", NULL, NULL };
325
326 if (is_null_oid(stash))
327 return;
328
329 reset_hard(head, 1);
330
331 args[2] = oid_to_hex(stash);
332
333 /*
334 * It is OK to ignore error here, for example when there was
335 * nothing to restore.
336 */
337 run_command_v_opt(args, RUN_GIT_CMD);
338
339 strbuf_release(&sb);
340 refresh_cache(REFRESH_QUIET);
341 }
342
343 /* This is called when no merge was necessary. */
344 static void finish_up_to_date(const char *msg)
345 {
346 if (verbosity >= 0)
347 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
348 drop_save();
349 }
350
351 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
352 {
353 struct rev_info rev;
354 struct strbuf out = STRBUF_INIT;
355 struct commit_list *j;
356 struct pretty_print_context ctx = {0};
357
358 printf(_("Squash commit -- not updating HEAD\n"));
359
360 init_revisions(&rev, NULL);
361 rev.ignore_merges = 1;
362 rev.commit_format = CMIT_FMT_MEDIUM;
363
364 commit->object.flags |= UNINTERESTING;
365 add_pending_object(&rev, &commit->object, NULL);
366
367 for (j = remoteheads; j; j = j->next)
368 add_pending_object(&rev, &j->item->object, NULL);
369
370 setup_revisions(0, NULL, &rev, NULL);
371 if (prepare_revision_walk(&rev))
372 die(_("revision walk setup failed"));
373
374 ctx.abbrev = rev.abbrev;
375 ctx.date_mode = rev.date_mode;
376 ctx.fmt = rev.commit_format;
377
378 strbuf_addstr(&out, "Squashed commit of the following:\n");
379 while ((commit = get_revision(&rev)) != NULL) {
380 strbuf_addch(&out, '\n');
381 strbuf_addf(&out, "commit %s\n",
382 oid_to_hex(&commit->object.oid));
383 pretty_print_commit(&ctx, commit, &out);
384 }
385 write_file_buf(git_path_squash_msg(), out.buf, out.len);
386 strbuf_release(&out);
387 }
388
389 static void finish(struct commit *head_commit,
390 struct commit_list *remoteheads,
391 const struct object_id *new_head, const char *msg)
392 {
393 struct strbuf reflog_message = STRBUF_INIT;
394 const struct object_id *head = &head_commit->object.oid;
395
396 if (!msg)
397 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
398 else {
399 if (verbosity >= 0)
400 printf("%s\n", msg);
401 strbuf_addf(&reflog_message, "%s: %s",
402 getenv("GIT_REFLOG_ACTION"), msg);
403 }
404 if (squash) {
405 squash_message(head_commit, remoteheads);
406 } else {
407 if (verbosity >= 0 && !merge_msg.len)
408 printf(_("No merge message -- not updating HEAD\n"));
409 else {
410 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
411 update_ref(reflog_message.buf, "HEAD", new_head, head,
412 0, UPDATE_REFS_DIE_ON_ERR);
413 /*
414 * We ignore errors in 'gc --auto', since the
415 * user should see them.
416 */
417 close_all_packs(the_repository->objects);
418 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
419 }
420 }
421 if (new_head && show_diffstat) {
422 struct diff_options opts;
423 diff_setup(&opts);
424 opts.stat_width = -1; /* use full terminal width */
425 opts.stat_graph_width = -1; /* respect statGraphWidth config */
426 opts.output_format |=
427 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
428 opts.detect_rename = DIFF_DETECT_RENAME;
429 diff_setup_done(&opts);
430 diff_tree_oid(head, new_head, "", &opts);
431 diffcore_std(&opts);
432 diff_flush(&opts);
433 }
434
435 /* Run a post-merge hook */
436 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
437
438 strbuf_release(&reflog_message);
439 }
440
441 /* Get the name for the merge commit's message. */
442 static void merge_name(const char *remote, struct strbuf *msg)
443 {
444 struct commit *remote_head;
445 struct object_id branch_head;
446 struct strbuf buf = STRBUF_INIT;
447 struct strbuf bname = STRBUF_INIT;
448 const char *ptr;
449 char *found_ref;
450 int len, early;
451
452 strbuf_branchname(&bname, remote, 0);
453 remote = bname.buf;
454
455 oidclr(&branch_head);
456 remote_head = get_merge_parent(remote);
457 if (!remote_head)
458 die(_("'%s' does not point to a commit"), remote);
459
460 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
461 if (starts_with(found_ref, "refs/heads/")) {
462 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
463 oid_to_hex(&branch_head), remote);
464 goto cleanup;
465 }
466 if (starts_with(found_ref, "refs/tags/")) {
467 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
468 oid_to_hex(&branch_head), remote);
469 goto cleanup;
470 }
471 if (starts_with(found_ref, "refs/remotes/")) {
472 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
473 oid_to_hex(&branch_head), remote);
474 goto cleanup;
475 }
476 }
477
478 /* See if remote matches <name>^^^.. or <name>~<number> */
479 for (len = 0, ptr = remote + strlen(remote);
480 remote < ptr && ptr[-1] == '^';
481 ptr--)
482 len++;
483 if (len)
484 early = 1;
485 else {
486 early = 0;
487 ptr = strrchr(remote, '~');
488 if (ptr) {
489 int seen_nonzero = 0;
490
491 len++; /* count ~ */
492 while (*++ptr && isdigit(*ptr)) {
493 seen_nonzero |= (*ptr != '0');
494 len++;
495 }
496 if (*ptr)
497 len = 0; /* not ...~<number> */
498 else if (seen_nonzero)
499 early = 1;
500 else if (len == 1)
501 early = 1; /* "name~" is "name~1"! */
502 }
503 }
504 if (len) {
505 struct strbuf truname = STRBUF_INIT;
506 strbuf_addf(&truname, "refs/heads/%s", remote);
507 strbuf_setlen(&truname, truname.len - len);
508 if (ref_exists(truname.buf)) {
509 strbuf_addf(msg,
510 "%s\t\tbranch '%s'%s of .\n",
511 oid_to_hex(&remote_head->object.oid),
512 truname.buf + 11,
513 (early ? " (early part)" : ""));
514 strbuf_release(&truname);
515 goto cleanup;
516 }
517 strbuf_release(&truname);
518 }
519
520 if (remote_head->util) {
521 struct merge_remote_desc *desc;
522 desc = merge_remote_util(remote_head);
523 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
524 strbuf_addf(msg, "%s\t\t%s '%s'\n",
525 oid_to_hex(&desc->obj->oid),
526 type_name(desc->obj->type),
527 remote);
528 goto cleanup;
529 }
530 }
531
532 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
533 oid_to_hex(&remote_head->object.oid), remote);
534 cleanup:
535 strbuf_release(&buf);
536 strbuf_release(&bname);
537 }
538
539 static void parse_branch_merge_options(char *bmo)
540 {
541 const char **argv;
542 int argc;
543
544 if (!bmo)
545 return;
546 argc = split_cmdline(bmo, &argv);
547 if (argc < 0)
548 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
549 split_cmdline_strerror(argc));
550 REALLOC_ARRAY(argv, argc + 2);
551 MOVE_ARRAY(argv + 1, argv, argc + 1);
552 argc++;
553 argv[0] = "branch.*.mergeoptions";
554 parse_options(argc, argv, NULL, builtin_merge_options,
555 builtin_merge_usage, 0);
556 free(argv);
557 }
558
559 static int git_merge_config(const char *k, const char *v, void *cb)
560 {
561 int status;
562
563 if (branch && starts_with(k, "branch.") &&
564 starts_with(k + 7, branch) &&
565 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
566 free(branch_mergeoptions);
567 branch_mergeoptions = xstrdup(v);
568 return 0;
569 }
570
571 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
572 show_diffstat = git_config_bool(k, v);
573 else if (!strcmp(k, "merge.verifysignatures"))
574 verify_signatures = git_config_bool(k, v);
575 else if (!strcmp(k, "pull.twohead"))
576 return git_config_string(&pull_twohead, k, v);
577 else if (!strcmp(k, "pull.octopus"))
578 return git_config_string(&pull_octopus, k, v);
579 else if (!strcmp(k, "merge.renormalize"))
580 option_renormalize = git_config_bool(k, v);
581 else if (!strcmp(k, "merge.ff")) {
582 int boolval = git_parse_maybe_bool(v);
583 if (0 <= boolval) {
584 fast_forward = boolval ? FF_ALLOW : FF_NO;
585 } else if (v && !strcmp(v, "only")) {
586 fast_forward = FF_ONLY;
587 } /* do not barf on values from future versions of git */
588 return 0;
589 } else if (!strcmp(k, "merge.defaulttoupstream")) {
590 default_to_upstream = git_config_bool(k, v);
591 return 0;
592 } else if (!strcmp(k, "commit.gpgsign")) {
593 sign_commit = git_config_bool(k, v) ? "" : NULL;
594 return 0;
595 }
596
597 status = fmt_merge_msg_config(k, v, cb);
598 if (status)
599 return status;
600 status = git_gpg_config(k, v, NULL);
601 if (status)
602 return status;
603 return git_diff_ui_config(k, v, cb);
604 }
605
606 static int read_tree_trivial(struct object_id *common, struct object_id *head,
607 struct object_id *one)
608 {
609 int i, nr_trees = 0;
610 struct tree *trees[MAX_UNPACK_TREES];
611 struct tree_desc t[MAX_UNPACK_TREES];
612 struct unpack_trees_options opts;
613
614 memset(&opts, 0, sizeof(opts));
615 opts.head_idx = 2;
616 opts.src_index = &the_index;
617 opts.dst_index = &the_index;
618 opts.update = 1;
619 opts.verbose_update = 1;
620 opts.trivial_merges_only = 1;
621 opts.merge = 1;
622 trees[nr_trees] = parse_tree_indirect(common);
623 if (!trees[nr_trees++])
624 return -1;
625 trees[nr_trees] = parse_tree_indirect(head);
626 if (!trees[nr_trees++])
627 return -1;
628 trees[nr_trees] = parse_tree_indirect(one);
629 if (!trees[nr_trees++])
630 return -1;
631 opts.fn = threeway_merge;
632 cache_tree_free(&active_cache_tree);
633 for (i = 0; i < nr_trees; i++) {
634 parse_tree(trees[i]);
635 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
636 }
637 if (unpack_trees(nr_trees, t, &opts))
638 return -1;
639 return 0;
640 }
641
642 static void write_tree_trivial(struct object_id *oid)
643 {
644 if (write_cache_as_tree(oid, 0, NULL))
645 die(_("git write-tree failed to write a tree"));
646 }
647
648 static int try_merge_strategy(const char *strategy, struct commit_list *common,
649 struct commit_list *remoteheads,
650 struct commit *head)
651 {
652 struct lock_file lock = LOCK_INIT;
653 const char *head_arg = "HEAD";
654
655 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
656 refresh_cache(REFRESH_QUIET);
657 if (write_locked_index(&the_index, &lock,
658 COMMIT_LOCK | SKIP_IF_UNCHANGED))
659 return error(_("Unable to write index."));
660
661 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
662 int clean, x;
663 struct commit *result;
664 struct commit_list *reversed = NULL;
665 struct merge_options o;
666 struct commit_list *j;
667
668 if (remoteheads->next) {
669 error(_("Not handling anything other than two heads merge."));
670 return 2;
671 }
672
673 init_merge_options(&o);
674 if (!strcmp(strategy, "subtree"))
675 o.subtree_shift = "";
676
677 o.renormalize = option_renormalize;
678 o.show_rename_progress =
679 show_progress == -1 ? isatty(2) : show_progress;
680
681 for (x = 0; x < xopts_nr; x++)
682 if (parse_merge_opt(&o, xopts[x]))
683 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
684
685 o.branch1 = head_arg;
686 o.branch2 = merge_remote_util(remoteheads->item)->name;
687
688 for (j = common; j; j = j->next)
689 commit_list_insert(j->item, &reversed);
690
691 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
692 clean = merge_recursive(&o, head,
693 remoteheads->item, reversed, &result);
694 if (clean < 0)
695 exit(128);
696 if (write_locked_index(&the_index, &lock,
697 COMMIT_LOCK | SKIP_IF_UNCHANGED))
698 die (_("unable to write %s"), get_index_file());
699 return clean ? 0 : 1;
700 } else {
701 return try_merge_command(strategy, xopts_nr, xopts,
702 common, head_arg, remoteheads);
703 }
704 }
705
706 static void count_diff_files(struct diff_queue_struct *q,
707 struct diff_options *opt, void *data)
708 {
709 int *count = data;
710
711 (*count) += q->nr;
712 }
713
714 static int count_unmerged_entries(void)
715 {
716 int i, ret = 0;
717
718 for (i = 0; i < active_nr; i++)
719 if (ce_stage(active_cache[i]))
720 ret++;
721
722 return ret;
723 }
724
725 static void add_strategies(const char *string, unsigned attr)
726 {
727 int i;
728
729 if (string) {
730 struct string_list list = STRING_LIST_INIT_DUP;
731 struct string_list_item *item;
732 string_list_split(&list, string, ' ', -1);
733 for_each_string_list_item(item, &list)
734 append_strategy(get_strategy(item->string));
735 string_list_clear(&list, 0);
736 return;
737 }
738 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
739 if (all_strategy[i].attr & attr)
740 append_strategy(&all_strategy[i]);
741
742 }
743
744 static void read_merge_msg(struct strbuf *msg)
745 {
746 const char *filename = git_path_merge_msg();
747 strbuf_reset(msg);
748 if (strbuf_read_file(msg, filename, 0) < 0)
749 die_errno(_("Could not read from '%s'"), filename);
750 }
751
752 static void write_merge_state(struct commit_list *);
753 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
754 {
755 if (err_msg)
756 error("%s", err_msg);
757 fprintf(stderr,
758 _("Not committing merge; use 'git commit' to complete the merge.\n"));
759 write_merge_state(remoteheads);
760 exit(1);
761 }
762
763 static const char merge_editor_comment[] =
764 N_("Please enter a commit message to explain why this merge is necessary,\n"
765 "especially if it merges an updated upstream into a topic branch.\n"
766 "\n"
767 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
768 "the commit.\n");
769
770 static void write_merge_heads(struct commit_list *);
771 static void prepare_to_commit(struct commit_list *remoteheads)
772 {
773 struct strbuf msg = STRBUF_INIT;
774 strbuf_addbuf(&msg, &merge_msg);
775 strbuf_addch(&msg, '\n');
776 if (squash)
777 BUG("the control must not reach here under --squash");
778 if (0 < option_edit)
779 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
780 if (signoff)
781 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
782 write_merge_heads(remoteheads);
783 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
784 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
785 git_path_merge_msg(), "merge", NULL))
786 abort_commit(remoteheads, NULL);
787 if (0 < option_edit) {
788 if (launch_editor(git_path_merge_msg(), NULL, NULL))
789 abort_commit(remoteheads, NULL);
790 }
791
792 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
793 "commit-msg",
794 git_path_merge_msg(), NULL))
795 abort_commit(remoteheads, NULL);
796
797 read_merge_msg(&msg);
798 strbuf_stripspace(&msg, 0 < option_edit);
799 if (!msg.len)
800 abort_commit(remoteheads, _("Empty commit message."));
801 strbuf_release(&merge_msg);
802 strbuf_addbuf(&merge_msg, &msg);
803 strbuf_release(&msg);
804 }
805
806 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
807 {
808 struct object_id result_tree, result_commit;
809 struct commit_list *parents, **pptr = &parents;
810 struct lock_file lock = LOCK_INIT;
811
812 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
813 refresh_cache(REFRESH_QUIET);
814 if (write_locked_index(&the_index, &lock,
815 COMMIT_LOCK | SKIP_IF_UNCHANGED))
816 return error(_("Unable to write index."));
817
818 write_tree_trivial(&result_tree);
819 printf(_("Wonderful.\n"));
820 pptr = commit_list_append(head, pptr);
821 pptr = commit_list_append(remoteheads->item, pptr);
822 prepare_to_commit(remoteheads);
823 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
824 &result_commit, NULL, sign_commit))
825 die(_("failed to write commit object"));
826 finish(head, remoteheads, &result_commit, "In-index merge");
827 drop_save();
828 return 0;
829 }
830
831 static int finish_automerge(struct commit *head,
832 int head_subsumed,
833 struct commit_list *common,
834 struct commit_list *remoteheads,
835 struct object_id *result_tree,
836 const char *wt_strategy)
837 {
838 struct commit_list *parents = NULL;
839 struct strbuf buf = STRBUF_INIT;
840 struct object_id result_commit;
841
842 free_commit_list(common);
843 parents = remoteheads;
844 if (!head_subsumed || fast_forward == FF_NO)
845 commit_list_insert(head, &parents);
846 strbuf_addch(&merge_msg, '\n');
847 prepare_to_commit(remoteheads);
848 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
849 &result_commit, NULL, sign_commit))
850 die(_("failed to write commit object"));
851 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
852 finish(head, remoteheads, &result_commit, buf.buf);
853 strbuf_release(&buf);
854 drop_save();
855 return 0;
856 }
857
858 static int suggest_conflicts(void)
859 {
860 const char *filename;
861 FILE *fp;
862 struct strbuf msgbuf = STRBUF_INIT;
863
864 filename = git_path_merge_msg();
865 fp = xfopen(filename, "a");
866
867 append_conflicts_hint(&msgbuf);
868 fputs(msgbuf.buf, fp);
869 strbuf_release(&msgbuf);
870 fclose(fp);
871 rerere(allow_rerere_auto);
872 printf(_("Automatic merge failed; "
873 "fix conflicts and then commit the result.\n"));
874 return 1;
875 }
876
877 static int evaluate_result(void)
878 {
879 int cnt = 0;
880 struct rev_info rev;
881
882 /* Check how many files differ. */
883 init_revisions(&rev, "");
884 setup_revisions(0, NULL, &rev, NULL);
885 rev.diffopt.output_format |=
886 DIFF_FORMAT_CALLBACK;
887 rev.diffopt.format_callback = count_diff_files;
888 rev.diffopt.format_callback_data = &cnt;
889 run_diff_files(&rev, 0);
890
891 /*
892 * Check how many unmerged entries are
893 * there.
894 */
895 cnt += count_unmerged_entries();
896
897 return cnt;
898 }
899
900 /*
901 * Pretend as if the user told us to merge with the remote-tracking
902 * branch we have for the upstream of the current branch
903 */
904 static int setup_with_upstream(const char ***argv)
905 {
906 struct branch *branch = branch_get(NULL);
907 int i;
908 const char **args;
909
910 if (!branch)
911 die(_("No current branch."));
912 if (!branch->remote_name)
913 die(_("No remote for the current branch."));
914 if (!branch->merge_nr)
915 die(_("No default upstream defined for the current branch."));
916
917 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
918 for (i = 0; i < branch->merge_nr; i++) {
919 if (!branch->merge[i]->dst)
920 die(_("No remote-tracking branch for %s from %s"),
921 branch->merge[i]->src, branch->remote_name);
922 args[i] = branch->merge[i]->dst;
923 }
924 args[i] = NULL;
925 *argv = args;
926 return i;
927 }
928
929 static void write_merge_heads(struct commit_list *remoteheads)
930 {
931 struct commit_list *j;
932 struct strbuf buf = STRBUF_INIT;
933
934 for (j = remoteheads; j; j = j->next) {
935 struct object_id *oid;
936 struct commit *c = j->item;
937 if (c->util && merge_remote_util(c)->obj) {
938 oid = &merge_remote_util(c)->obj->oid;
939 } else {
940 oid = &c->object.oid;
941 }
942 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
943 }
944 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
945
946 strbuf_reset(&buf);
947 if (fast_forward == FF_NO)
948 strbuf_addstr(&buf, "no-ff");
949 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
950 strbuf_release(&buf);
951 }
952
953 static void write_merge_state(struct commit_list *remoteheads)
954 {
955 write_merge_heads(remoteheads);
956 strbuf_addch(&merge_msg, '\n');
957 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
958 }
959
960 static int default_edit_option(void)
961 {
962 static const char name[] = "GIT_MERGE_AUTOEDIT";
963 const char *e = getenv(name);
964 struct stat st_stdin, st_stdout;
965
966 if (have_message)
967 /* an explicit -m msg without --[no-]edit */
968 return 0;
969
970 if (e) {
971 int v = git_parse_maybe_bool(e);
972 if (v < 0)
973 die(_("Bad value '%s' in environment '%s'"), e, name);
974 return v;
975 }
976
977 /* Use editor if stdin and stdout are the same and is a tty */
978 return (!fstat(0, &st_stdin) &&
979 !fstat(1, &st_stdout) &&
980 isatty(0) && isatty(1) &&
981 st_stdin.st_dev == st_stdout.st_dev &&
982 st_stdin.st_ino == st_stdout.st_ino &&
983 st_stdin.st_mode == st_stdout.st_mode);
984 }
985
986 static struct commit_list *reduce_parents(struct commit *head_commit,
987 int *head_subsumed,
988 struct commit_list *remoteheads)
989 {
990 struct commit_list *parents, **remotes;
991
992 /*
993 * Is the current HEAD reachable from another commit being
994 * merged? If so we do not want to record it as a parent of
995 * the resulting merge, unless --no-ff is given. We will flip
996 * this variable to 0 when we find HEAD among the independent
997 * tips being merged.
998 */
999 *head_subsumed = 1;
1000
1001 /* Find what parents to record by checking independent ones. */
1002 parents = reduce_heads(remoteheads);
1003 free_commit_list(remoteheads);
1004
1005 remoteheads = NULL;
1006 remotes = &remoteheads;
1007 while (parents) {
1008 struct commit *commit = pop_commit(&parents);
1009 if (commit == head_commit)
1010 *head_subsumed = 0;
1011 else
1012 remotes = &commit_list_insert(commit, remotes)->next;
1013 }
1014 return remoteheads;
1015 }
1016
1017 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1018 {
1019 struct fmt_merge_msg_opts opts;
1020
1021 memset(&opts, 0, sizeof(opts));
1022 opts.add_title = !have_message;
1023 opts.shortlog_len = shortlog_len;
1024 opts.credit_people = (0 < option_edit);
1025
1026 fmt_merge_msg(merge_names, merge_msg, &opts);
1027 if (merge_msg->len)
1028 strbuf_setlen(merge_msg, merge_msg->len - 1);
1029 }
1030
1031 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1032 {
1033 const char *filename;
1034 int fd, pos, npos;
1035 struct strbuf fetch_head_file = STRBUF_INIT;
1036
1037 if (!merge_names)
1038 merge_names = &fetch_head_file;
1039
1040 filename = git_path_fetch_head();
1041 fd = open(filename, O_RDONLY);
1042 if (fd < 0)
1043 die_errno(_("could not open '%s' for reading"), filename);
1044
1045 if (strbuf_read(merge_names, fd, 0) < 0)
1046 die_errno(_("could not read '%s'"), filename);
1047 if (close(fd) < 0)
1048 die_errno(_("could not close '%s'"), filename);
1049
1050 for (pos = 0; pos < merge_names->len; pos = npos) {
1051 struct object_id oid;
1052 char *ptr;
1053 struct commit *commit;
1054
1055 ptr = strchr(merge_names->buf + pos, '\n');
1056 if (ptr)
1057 npos = ptr - merge_names->buf + 1;
1058 else
1059 npos = merge_names->len;
1060
1061 if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
1062 get_oid_hex(merge_names->buf + pos, &oid))
1063 commit = NULL; /* bad */
1064 else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
1065 continue; /* not-for-merge */
1066 else {
1067 char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
1068 merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
1069 commit = get_merge_parent(merge_names->buf + pos);
1070 merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
1071 }
1072 if (!commit) {
1073 if (ptr)
1074 *ptr = '\0';
1075 die(_("not something we can merge in %s: %s"),
1076 filename, merge_names->buf + pos);
1077 }
1078 remotes = &commit_list_insert(commit, remotes)->next;
1079 }
1080
1081 if (merge_names == &fetch_head_file)
1082 strbuf_release(&fetch_head_file);
1083 }
1084
1085 static struct commit_list *collect_parents(struct commit *head_commit,
1086 int *head_subsumed,
1087 int argc, const char **argv,
1088 struct strbuf *merge_msg)
1089 {
1090 int i;
1091 struct commit_list *remoteheads = NULL;
1092 struct commit_list **remotes = &remoteheads;
1093 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1094
1095 if (merge_msg && (!have_message || shortlog_len))
1096 autogen = &merge_names;
1097
1098 if (head_commit)
1099 remotes = &commit_list_insert(head_commit, remotes)->next;
1100
1101 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1102 handle_fetch_head(remotes, autogen);
1103 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1104 } else {
1105 for (i = 0; i < argc; i++) {
1106 struct commit *commit = get_merge_parent(argv[i]);
1107 if (!commit)
1108 help_unknown_ref(argv[i], "merge",
1109 _("not something we can merge"));
1110 remotes = &commit_list_insert(commit, remotes)->next;
1111 }
1112 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1113 if (autogen) {
1114 struct commit_list *p;
1115 for (p = remoteheads; p; p = p->next)
1116 merge_name(merge_remote_util(p->item)->name, autogen);
1117 }
1118 }
1119
1120 if (autogen) {
1121 prepare_merge_message(autogen, merge_msg);
1122 strbuf_release(autogen);
1123 }
1124
1125 return remoteheads;
1126 }
1127
1128 static int merging_a_throwaway_tag(struct commit *commit)
1129 {
1130 char *tag_ref;
1131 struct object_id oid;
1132 int is_throwaway_tag = 0;
1133
1134 /* Are we merging a tag? */
1135 if (!merge_remote_util(commit) ||
1136 !merge_remote_util(commit)->obj ||
1137 merge_remote_util(commit)->obj->type != OBJ_TAG)
1138 return is_throwaway_tag;
1139
1140 /*
1141 * Now we know we are merging a tag object. Are we downstream
1142 * and following the tags from upstream? If so, we must have
1143 * the tag object pointed at by "refs/tags/$T" where $T is the
1144 * tagname recorded in the tag object. We want to allow such
1145 * a "just to catch up" merge to fast-forward.
1146 *
1147 * Otherwise, we are playing an integrator's role, making a
1148 * merge with a throw-away tag from a contributor with
1149 * something like "git pull $contributor $signed_tag".
1150 * We want to forbid such a merge from fast-forwarding
1151 * by default; otherwise we would not keep the signature
1152 * anywhere.
1153 */
1154 tag_ref = xstrfmt("refs/tags/%s",
1155 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1156 if (!read_ref(tag_ref, &oid) &&
1157 !oidcmp(&oid, &merge_remote_util(commit)->obj->oid))
1158 is_throwaway_tag = 0;
1159 else
1160 is_throwaway_tag = 1;
1161 free(tag_ref);
1162 return is_throwaway_tag;
1163 }
1164
1165 int cmd_merge(int argc, const char **argv, const char *prefix)
1166 {
1167 struct object_id result_tree, stash, head_oid;
1168 struct commit *head_commit;
1169 struct strbuf buf = STRBUF_INIT;
1170 int i, ret = 0, head_subsumed;
1171 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1172 struct commit_list *common = NULL;
1173 const char *best_strategy = NULL, *wt_strategy = NULL;
1174 struct commit_list *remoteheads, *p;
1175 void *branch_to_free;
1176 int orig_argc = argc;
1177
1178 if (argc == 2 && !strcmp(argv[1], "-h"))
1179 usage_with_options(builtin_merge_usage, builtin_merge_options);
1180
1181 /*
1182 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1183 * current branch.
1184 */
1185 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1186 if (branch)
1187 skip_prefix(branch, "refs/heads/", &branch);
1188 if (!branch || is_null_oid(&head_oid))
1189 head_commit = NULL;
1190 else
1191 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1192
1193 init_diff_ui_defaults();
1194 git_config(git_merge_config, NULL);
1195
1196 if (branch_mergeoptions)
1197 parse_branch_merge_options(branch_mergeoptions);
1198 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1199 builtin_merge_usage, 0);
1200 if (shortlog_len < 0)
1201 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1202
1203 if (verbosity < 0 && show_progress == -1)
1204 show_progress = 0;
1205
1206 if (abort_current_merge) {
1207 int nargc = 2;
1208 const char *nargv[] = {"reset", "--merge", NULL};
1209
1210 if (orig_argc != 2)
1211 usage_msg_opt(_("--abort expects no arguments"),
1212 builtin_merge_usage, builtin_merge_options);
1213
1214 if (!file_exists(git_path_merge_head()))
1215 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1216
1217 /* Invoke 'git reset --merge' */
1218 ret = cmd_reset(nargc, nargv, prefix);
1219 goto done;
1220 }
1221
1222 if (continue_current_merge) {
1223 int nargc = 1;
1224 const char *nargv[] = {"commit", NULL};
1225
1226 if (orig_argc != 2)
1227 usage_msg_opt(_("--continue expects no arguments"),
1228 builtin_merge_usage, builtin_merge_options);
1229
1230 if (!file_exists(git_path_merge_head()))
1231 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1232
1233 /* Invoke 'git commit' */
1234 ret = cmd_commit(nargc, nargv, prefix);
1235 goto done;
1236 }
1237
1238 if (read_cache_unmerged())
1239 die_resolve_conflict("merge");
1240
1241 if (file_exists(git_path_merge_head())) {
1242 /*
1243 * There is no unmerged entry, don't advise 'git
1244 * add/rm <file>', just 'git commit'.
1245 */
1246 if (advice_resolve_conflict)
1247 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1248 "Please, commit your changes before you merge."));
1249 else
1250 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1251 }
1252 if (file_exists(git_path_cherry_pick_head())) {
1253 if (advice_resolve_conflict)
1254 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1255 "Please, commit your changes before you merge."));
1256 else
1257 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1258 }
1259 resolve_undo_clear();
1260
1261 if (verbosity < 0)
1262 show_diffstat = 0;
1263
1264 if (squash) {
1265 if (fast_forward == FF_NO)
1266 die(_("You cannot combine --squash with --no-ff."));
1267 option_commit = 0;
1268 }
1269
1270 if (!argc) {
1271 if (default_to_upstream)
1272 argc = setup_with_upstream(&argv);
1273 else
1274 die(_("No commit specified and merge.defaultToUpstream not set."));
1275 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1276 argv[0] = "@{-1}";
1277 }
1278
1279 if (!argc)
1280 usage_with_options(builtin_merge_usage,
1281 builtin_merge_options);
1282
1283 if (!head_commit) {
1284 /*
1285 * If the merged head is a valid one there is no reason
1286 * to forbid "git merge" into a branch yet to be born.
1287 * We do the same for "git pull".
1288 */
1289 struct object_id *remote_head_oid;
1290 if (squash)
1291 die(_("Squash commit into empty head not supported yet"));
1292 if (fast_forward == FF_NO)
1293 die(_("Non-fast-forward commit does not make sense into "
1294 "an empty head"));
1295 remoteheads = collect_parents(head_commit, &head_subsumed,
1296 argc, argv, NULL);
1297 if (!remoteheads)
1298 die(_("%s - not something we can merge"), argv[0]);
1299 if (remoteheads->next)
1300 die(_("Can merge only exactly one commit into empty head"));
1301 remote_head_oid = &remoteheads->item->object.oid;
1302 read_empty(remote_head_oid, 0);
1303 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1304 UPDATE_REFS_DIE_ON_ERR);
1305 goto done;
1306 }
1307
1308 /*
1309 * All the rest are the commits being merged; prepare
1310 * the standard merge summary message to be appended
1311 * to the given message.
1312 */
1313 remoteheads = collect_parents(head_commit, &head_subsumed,
1314 argc, argv, &merge_msg);
1315
1316 if (!head_commit || !argc)
1317 usage_with_options(builtin_merge_usage,
1318 builtin_merge_options);
1319
1320 if (verify_signatures) {
1321 for (p = remoteheads; p; p = p->next) {
1322 struct commit *commit = p->item;
1323 char hex[GIT_MAX_HEXSZ + 1];
1324 struct signature_check signature_check;
1325 memset(&signature_check, 0, sizeof(signature_check));
1326
1327 check_commit_signature(commit, &signature_check);
1328
1329 find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1330 switch (signature_check.result) {
1331 case 'G':
1332 break;
1333 case 'U':
1334 die(_("Commit %s has an untrusted GPG signature, "
1335 "allegedly by %s."), hex, signature_check.signer);
1336 case 'B':
1337 die(_("Commit %s has a bad GPG signature "
1338 "allegedly by %s."), hex, signature_check.signer);
1339 default: /* 'N' */
1340 die(_("Commit %s does not have a GPG signature."), hex);
1341 }
1342 if (verbosity >= 0 && signature_check.result == 'G')
1343 printf(_("Commit %s has a good GPG signature by %s\n"),
1344 hex, signature_check.signer);
1345
1346 signature_check_clear(&signature_check);
1347 }
1348 }
1349
1350 strbuf_addstr(&buf, "merge");
1351 for (p = remoteheads; p; p = p->next)
1352 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1353 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1354 strbuf_reset(&buf);
1355
1356 for (p = remoteheads; p; p = p->next) {
1357 struct commit *commit = p->item;
1358 strbuf_addf(&buf, "GITHEAD_%s",
1359 oid_to_hex(&commit->object.oid));
1360 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1361 strbuf_reset(&buf);
1362 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1363 fast_forward = FF_NO;
1364 }
1365
1366 if (option_edit < 0)
1367 option_edit = default_edit_option();
1368
1369 if (!use_strategies) {
1370 if (!remoteheads)
1371 ; /* already up-to-date */
1372 else if (!remoteheads->next)
1373 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1374 else
1375 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1376 }
1377
1378 for (i = 0; i < use_strategies_nr; i++) {
1379 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1380 fast_forward = FF_NO;
1381 if (use_strategies[i]->attr & NO_TRIVIAL)
1382 allow_trivial = 0;
1383 }
1384
1385 if (!remoteheads)
1386 ; /* already up-to-date */
1387 else if (!remoteheads->next)
1388 common = get_merge_bases(head_commit, remoteheads->item);
1389 else {
1390 struct commit_list *list = remoteheads;
1391 commit_list_insert(head_commit, &list);
1392 common = get_octopus_merge_bases(list);
1393 free(list);
1394 }
1395
1396 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1397 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1398
1399 if (remoteheads && !common) {
1400 /* No common ancestors found. */
1401 if (!allow_unrelated_histories)
1402 die(_("refusing to merge unrelated histories"));
1403 /* otherwise, we need a real merge. */
1404 } else if (!remoteheads ||
1405 (!remoteheads->next && !common->next &&
1406 common->item == remoteheads->item)) {
1407 /*
1408 * If head can reach all the merge then we are up to date.
1409 * but first the most common case of merging one remote.
1410 */
1411 finish_up_to_date(_("Already up to date."));
1412 goto done;
1413 } else if (fast_forward != FF_NO && !remoteheads->next &&
1414 !common->next &&
1415 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1416 /* Again the most common case of merging one remote. */
1417 struct strbuf msg = STRBUF_INIT;
1418 struct commit *commit;
1419
1420 if (verbosity >= 0) {
1421 printf(_("Updating %s..%s\n"),
1422 find_unique_abbrev(&head_commit->object.oid,
1423 DEFAULT_ABBREV),
1424 find_unique_abbrev(&remoteheads->item->object.oid,
1425 DEFAULT_ABBREV));
1426 }
1427 strbuf_addstr(&msg, "Fast-forward");
1428 if (have_message)
1429 strbuf_addstr(&msg,
1430 " (no commit created; -m option ignored)");
1431 commit = remoteheads->item;
1432 if (!commit) {
1433 ret = 1;
1434 goto done;
1435 }
1436
1437 if (checkout_fast_forward(&head_commit->object.oid,
1438 &commit->object.oid,
1439 overwrite_ignore)) {
1440 ret = 1;
1441 goto done;
1442 }
1443
1444 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1445 drop_save();
1446 goto done;
1447 } else if (!remoteheads->next && common->next)
1448 ;
1449 /*
1450 * We are not doing octopus and not fast-forward. Need
1451 * a real merge.
1452 */
1453 else if (!remoteheads->next && !common->next && option_commit) {
1454 /*
1455 * We are not doing octopus, not fast-forward, and have
1456 * only one common.
1457 */
1458 refresh_cache(REFRESH_QUIET);
1459 if (allow_trivial && fast_forward != FF_ONLY) {
1460 /* See if it is really trivial. */
1461 git_committer_info(IDENT_STRICT);
1462 printf(_("Trying really trivial in-index merge...\n"));
1463 if (!read_tree_trivial(&common->item->object.oid,
1464 &head_commit->object.oid,
1465 &remoteheads->item->object.oid)) {
1466 ret = merge_trivial(head_commit, remoteheads);
1467 goto done;
1468 }
1469 printf(_("Nope.\n"));
1470 }
1471 } else {
1472 /*
1473 * An octopus. If we can reach all the remote we are up
1474 * to date.
1475 */
1476 int up_to_date = 1;
1477 struct commit_list *j;
1478
1479 for (j = remoteheads; j; j = j->next) {
1480 struct commit_list *common_one;
1481
1482 /*
1483 * Here we *have* to calculate the individual
1484 * merge_bases again, otherwise "git merge HEAD^
1485 * HEAD^^" would be missed.
1486 */
1487 common_one = get_merge_bases(head_commit, j->item);
1488 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1489 up_to_date = 0;
1490 break;
1491 }
1492 }
1493 if (up_to_date) {
1494 finish_up_to_date(_("Already up to date. Yeeah!"));
1495 goto done;
1496 }
1497 }
1498
1499 if (fast_forward == FF_ONLY)
1500 die(_("Not possible to fast-forward, aborting."));
1501
1502 /* We are going to make a new commit. */
1503 git_committer_info(IDENT_STRICT);
1504
1505 /*
1506 * At this point, we need a real merge. No matter what strategy
1507 * we use, it would operate on the index, possibly affecting the
1508 * working tree, and when resolved cleanly, have the desired
1509 * tree in the index -- this means that the index must be in
1510 * sync with the head commit. The strategies are responsible
1511 * to ensure this.
1512 */
1513 if (use_strategies_nr == 1 ||
1514 /*
1515 * Stash away the local changes so that we can try more than one.
1516 */
1517 save_state(&stash))
1518 oidclr(&stash);
1519
1520 for (i = 0; i < use_strategies_nr; i++) {
1521 int ret;
1522 if (i) {
1523 printf(_("Rewinding the tree to pristine...\n"));
1524 restore_state(&head_commit->object.oid, &stash);
1525 }
1526 if (use_strategies_nr != 1)
1527 printf(_("Trying merge strategy %s...\n"),
1528 use_strategies[i]->name);
1529 /*
1530 * Remember which strategy left the state in the working
1531 * tree.
1532 */
1533 wt_strategy = use_strategies[i]->name;
1534
1535 ret = try_merge_strategy(use_strategies[i]->name,
1536 common, remoteheads,
1537 head_commit);
1538 if (!option_commit && !ret) {
1539 merge_was_ok = 1;
1540 /*
1541 * This is necessary here just to avoid writing
1542 * the tree, but later we will *not* exit with
1543 * status code 1 because merge_was_ok is set.
1544 */
1545 ret = 1;
1546 }
1547
1548 if (ret) {
1549 /*
1550 * The backend exits with 1 when conflicts are
1551 * left to be resolved, with 2 when it does not
1552 * handle the given merge at all.
1553 */
1554 if (ret == 1) {
1555 int cnt = evaluate_result();
1556
1557 if (best_cnt <= 0 || cnt <= best_cnt) {
1558 best_strategy = use_strategies[i]->name;
1559 best_cnt = cnt;
1560 }
1561 }
1562 if (merge_was_ok)
1563 break;
1564 else
1565 continue;
1566 }
1567
1568 /* Automerge succeeded. */
1569 write_tree_trivial(&result_tree);
1570 automerge_was_ok = 1;
1571 break;
1572 }
1573
1574 /*
1575 * If we have a resulting tree, that means the strategy module
1576 * auto resolved the merge cleanly.
1577 */
1578 if (automerge_was_ok) {
1579 ret = finish_automerge(head_commit, head_subsumed,
1580 common, remoteheads,
1581 &result_tree, wt_strategy);
1582 goto done;
1583 }
1584
1585 /*
1586 * Pick the result from the best strategy and have the user fix
1587 * it up.
1588 */
1589 if (!best_strategy) {
1590 restore_state(&head_commit->object.oid, &stash);
1591 if (use_strategies_nr > 1)
1592 fprintf(stderr,
1593 _("No merge strategy handled the merge.\n"));
1594 else
1595 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1596 use_strategies[0]->name);
1597 ret = 2;
1598 goto done;
1599 } else if (best_strategy == wt_strategy)
1600 ; /* We already have its result in the working tree. */
1601 else {
1602 printf(_("Rewinding the tree to pristine...\n"));
1603 restore_state(&head_commit->object.oid, &stash);
1604 printf(_("Using the %s to prepare resolving by hand.\n"),
1605 best_strategy);
1606 try_merge_strategy(best_strategy, common, remoteheads,
1607 head_commit);
1608 }
1609
1610 if (squash)
1611 finish(head_commit, remoteheads, NULL, NULL);
1612 else
1613 write_merge_state(remoteheads);
1614
1615 if (merge_was_ok)
1616 fprintf(stderr, _("Automatic merge went well; "
1617 "stopped before committing as requested\n"));
1618 else
1619 ret = suggest_conflicts();
1620
1621 done:
1622 free(branch_to_free);
1623 return ret;
1624 }