merge.c: remove implicit dependency on the_index
[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 int option_read_message(struct parse_opt_ctx_t *ctx,
115 const struct option *opt, int unset)
116 {
117 struct strbuf *buf = opt->value;
118 const char *arg;
119
120 if (unset)
121 BUG("-F cannot be negated");
122
123 if (ctx->opt) {
124 arg = ctx->opt;
125 ctx->opt = NULL;
126 } else if (ctx->argc > 1) {
127 ctx->argc--;
128 arg = *++ctx->argv;
129 } else
130 return opterror(opt, "requires a value", 0);
131
132 if (buf->len)
133 strbuf_addch(buf, '\n');
134 if (ctx->prefix && !is_absolute_path(arg))
135 arg = prefix_filename(ctx->prefix, arg);
136 if (strbuf_read_file(buf, arg, 0) < 0)
137 return error(_("could not read file '%s'"), arg);
138 have_message = 1;
139
140 return 0;
141 }
142
143 static struct strategy *get_strategy(const char *name)
144 {
145 int i;
146 struct strategy *ret;
147 static struct cmdnames main_cmds, other_cmds;
148 static int loaded;
149
150 if (!name)
151 return NULL;
152
153 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
154 if (!strcmp(name, all_strategy[i].name))
155 return &all_strategy[i];
156
157 if (!loaded) {
158 struct cmdnames not_strategies;
159 loaded = 1;
160
161 memset(&not_strategies, 0, sizeof(struct cmdnames));
162 load_command_list("git-merge-", &main_cmds, &other_cmds);
163 for (i = 0; i < main_cmds.cnt; i++) {
164 int j, found = 0;
165 struct cmdname *ent = main_cmds.names[i];
166 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
167 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
168 && !all_strategy[j].name[ent->len])
169 found = 1;
170 if (!found)
171 add_cmdname(&not_strategies, ent->name, ent->len);
172 }
173 exclude_cmds(&main_cmds, &not_strategies);
174 }
175 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
176 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
177 fprintf(stderr, _("Available strategies are:"));
178 for (i = 0; i < main_cmds.cnt; i++)
179 fprintf(stderr, " %s", main_cmds.names[i]->name);
180 fprintf(stderr, ".\n");
181 if (other_cmds.cnt) {
182 fprintf(stderr, _("Available custom strategies are:"));
183 for (i = 0; i < other_cmds.cnt; i++)
184 fprintf(stderr, " %s", other_cmds.names[i]->name);
185 fprintf(stderr, ".\n");
186 }
187 exit(1);
188 }
189
190 ret = xcalloc(1, sizeof(struct strategy));
191 ret->name = xstrdup(name);
192 ret->attr = NO_TRIVIAL;
193 return ret;
194 }
195
196 static void append_strategy(struct strategy *s)
197 {
198 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
199 use_strategies[use_strategies_nr++] = s;
200 }
201
202 static int option_parse_strategy(const struct option *opt,
203 const char *name, int unset)
204 {
205 if (unset)
206 return 0;
207
208 append_strategy(get_strategy(name));
209 return 0;
210 }
211
212 static int option_parse_x(const struct option *opt,
213 const char *arg, int unset)
214 {
215 if (unset)
216 return 0;
217
218 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
219 xopts[xopts_nr++] = xstrdup(arg);
220 return 0;
221 }
222
223 static int option_parse_n(const struct option *opt,
224 const char *arg, int unset)
225 {
226 show_diffstat = unset;
227 return 0;
228 }
229
230 static struct option builtin_merge_options[] = {
231 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
232 N_("do not show a diffstat at the end of the merge"),
233 PARSE_OPT_NOARG, option_parse_n },
234 OPT_BOOL(0, "stat", &show_diffstat,
235 N_("show a diffstat at the end of the merge")),
236 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
237 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
238 N_("add (at most <n>) entries from shortlog to merge commit message"),
239 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
240 OPT_BOOL(0, "squash", &squash,
241 N_("create a single commit instead of doing a merge")),
242 OPT_BOOL(0, "commit", &option_commit,
243 N_("perform a commit if the merge succeeds (default)")),
244 OPT_BOOL('e', "edit", &option_edit,
245 N_("edit message before committing")),
246 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
247 OPT_SET_INT_F(0, "ff-only", &fast_forward,
248 N_("abort if fast-forward is not possible"),
249 FF_ONLY, PARSE_OPT_NONEG),
250 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
251 OPT_BOOL(0, "verify-signatures", &verify_signatures,
252 N_("verify that the named commit has a valid GPG signature")),
253 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
254 N_("merge strategy to use"), option_parse_strategy),
255 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
256 N_("option for selected merge strategy"), option_parse_x),
257 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
258 N_("merge commit message (for a non-fast-forward merge)"),
259 option_parse_message),
260 { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
261 N_("read message from file"), PARSE_OPT_NONEG,
262 (parse_opt_cb *) option_read_message },
263 OPT__VERBOSITY(&verbosity),
264 OPT_BOOL(0, "abort", &abort_current_merge,
265 N_("abort the current in-progress merge")),
266 OPT_BOOL(0, "continue", &continue_current_merge,
267 N_("continue the current in-progress merge")),
268 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
269 N_("allow merging unrelated histories")),
270 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
271 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
272 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
273 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
274 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
275 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
276 OPT_END()
277 };
278
279 /* Cleans up metadata that is uninteresting after a succeeded merge. */
280 static void drop_save(void)
281 {
282 unlink(git_path_merge_head(the_repository));
283 unlink(git_path_merge_msg(the_repository));
284 unlink(git_path_merge_mode(the_repository));
285 }
286
287 static int save_state(struct object_id *stash)
288 {
289 int len;
290 struct child_process cp = CHILD_PROCESS_INIT;
291 struct strbuf buffer = STRBUF_INIT;
292 const char *argv[] = {"stash", "create", NULL};
293 int rc = -1;
294
295 cp.argv = argv;
296 cp.out = -1;
297 cp.git_cmd = 1;
298
299 if (start_command(&cp))
300 die(_("could not run stash."));
301 len = strbuf_read(&buffer, cp.out, 1024);
302 close(cp.out);
303
304 if (finish_command(&cp) || len < 0)
305 die(_("stash failed"));
306 else if (!len) /* no changes */
307 goto out;
308 strbuf_setlen(&buffer, buffer.len-1);
309 if (get_oid(buffer.buf, stash))
310 die(_("not a valid object: %s"), buffer.buf);
311 rc = 0;
312 out:
313 strbuf_release(&buffer);
314 return rc;
315 }
316
317 static void read_empty(const struct object_id *oid, int verbose)
318 {
319 int i = 0;
320 const char *args[7];
321
322 args[i++] = "read-tree";
323 if (verbose)
324 args[i++] = "-v";
325 args[i++] = "-m";
326 args[i++] = "-u";
327 args[i++] = empty_tree_oid_hex();
328 args[i++] = oid_to_hex(oid);
329 args[i] = NULL;
330
331 if (run_command_v_opt(args, RUN_GIT_CMD))
332 die(_("read-tree failed"));
333 }
334
335 static void reset_hard(const struct object_id *oid, int verbose)
336 {
337 int i = 0;
338 const char *args[6];
339
340 args[i++] = "read-tree";
341 if (verbose)
342 args[i++] = "-v";
343 args[i++] = "--reset";
344 args[i++] = "-u";
345 args[i++] = oid_to_hex(oid);
346 args[i] = NULL;
347
348 if (run_command_v_opt(args, RUN_GIT_CMD))
349 die(_("read-tree failed"));
350 }
351
352 static void restore_state(const struct object_id *head,
353 const struct object_id *stash)
354 {
355 struct strbuf sb = STRBUF_INIT;
356 const char *args[] = { "stash", "apply", NULL, NULL };
357
358 if (is_null_oid(stash))
359 return;
360
361 reset_hard(head, 1);
362
363 args[2] = oid_to_hex(stash);
364
365 /*
366 * It is OK to ignore error here, for example when there was
367 * nothing to restore.
368 */
369 run_command_v_opt(args, RUN_GIT_CMD);
370
371 strbuf_release(&sb);
372 refresh_cache(REFRESH_QUIET);
373 }
374
375 /* This is called when no merge was necessary. */
376 static void finish_up_to_date(const char *msg)
377 {
378 if (verbosity >= 0)
379 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
380 drop_save();
381 }
382
383 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
384 {
385 struct rev_info rev;
386 struct strbuf out = STRBUF_INIT;
387 struct commit_list *j;
388 struct pretty_print_context ctx = {0};
389
390 printf(_("Squash commit -- not updating HEAD\n"));
391
392 init_revisions(&rev, NULL);
393 rev.ignore_merges = 1;
394 rev.commit_format = CMIT_FMT_MEDIUM;
395
396 commit->object.flags |= UNINTERESTING;
397 add_pending_object(&rev, &commit->object, NULL);
398
399 for (j = remoteheads; j; j = j->next)
400 add_pending_object(&rev, &j->item->object, NULL);
401
402 setup_revisions(0, NULL, &rev, NULL);
403 if (prepare_revision_walk(&rev))
404 die(_("revision walk setup failed"));
405
406 ctx.abbrev = rev.abbrev;
407 ctx.date_mode = rev.date_mode;
408 ctx.fmt = rev.commit_format;
409
410 strbuf_addstr(&out, "Squashed commit of the following:\n");
411 while ((commit = get_revision(&rev)) != NULL) {
412 strbuf_addch(&out, '\n');
413 strbuf_addf(&out, "commit %s\n",
414 oid_to_hex(&commit->object.oid));
415 pretty_print_commit(&ctx, commit, &out);
416 }
417 write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
418 strbuf_release(&out);
419 }
420
421 static void finish(struct commit *head_commit,
422 struct commit_list *remoteheads,
423 const struct object_id *new_head, const char *msg)
424 {
425 struct strbuf reflog_message = STRBUF_INIT;
426 const struct object_id *head = &head_commit->object.oid;
427
428 if (!msg)
429 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
430 else {
431 if (verbosity >= 0)
432 printf("%s\n", msg);
433 strbuf_addf(&reflog_message, "%s: %s",
434 getenv("GIT_REFLOG_ACTION"), msg);
435 }
436 if (squash) {
437 squash_message(head_commit, remoteheads);
438 } else {
439 if (verbosity >= 0 && !merge_msg.len)
440 printf(_("No merge message -- not updating HEAD\n"));
441 else {
442 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
443 update_ref(reflog_message.buf, "HEAD", new_head, head,
444 0, UPDATE_REFS_DIE_ON_ERR);
445 /*
446 * We ignore errors in 'gc --auto', since the
447 * user should see them.
448 */
449 close_all_packs(the_repository->objects);
450 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
451 }
452 }
453 if (new_head && show_diffstat) {
454 struct diff_options opts;
455 repo_diff_setup(the_repository, &opts);
456 opts.stat_width = -1; /* use full terminal width */
457 opts.stat_graph_width = -1; /* respect statGraphWidth config */
458 opts.output_format |=
459 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
460 opts.detect_rename = DIFF_DETECT_RENAME;
461 diff_setup_done(&opts);
462 diff_tree_oid(head, new_head, "", &opts);
463 diffcore_std(&opts);
464 diff_flush(&opts);
465 }
466
467 /* Run a post-merge hook */
468 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
469
470 strbuf_release(&reflog_message);
471 }
472
473 /* Get the name for the merge commit's message. */
474 static void merge_name(const char *remote, struct strbuf *msg)
475 {
476 struct commit *remote_head;
477 struct object_id branch_head;
478 struct strbuf buf = STRBUF_INIT;
479 struct strbuf bname = STRBUF_INIT;
480 struct merge_remote_desc *desc;
481 const char *ptr;
482 char *found_ref;
483 int len, early;
484
485 strbuf_branchname(&bname, remote, 0);
486 remote = bname.buf;
487
488 oidclr(&branch_head);
489 remote_head = get_merge_parent(remote);
490 if (!remote_head)
491 die(_("'%s' does not point to a commit"), remote);
492
493 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
494 if (starts_with(found_ref, "refs/heads/")) {
495 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
496 oid_to_hex(&branch_head), remote);
497 goto cleanup;
498 }
499 if (starts_with(found_ref, "refs/tags/")) {
500 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
501 oid_to_hex(&branch_head), remote);
502 goto cleanup;
503 }
504 if (starts_with(found_ref, "refs/remotes/")) {
505 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
506 oid_to_hex(&branch_head), remote);
507 goto cleanup;
508 }
509 }
510
511 /* See if remote matches <name>^^^.. or <name>~<number> */
512 for (len = 0, ptr = remote + strlen(remote);
513 remote < ptr && ptr[-1] == '^';
514 ptr--)
515 len++;
516 if (len)
517 early = 1;
518 else {
519 early = 0;
520 ptr = strrchr(remote, '~');
521 if (ptr) {
522 int seen_nonzero = 0;
523
524 len++; /* count ~ */
525 while (*++ptr && isdigit(*ptr)) {
526 seen_nonzero |= (*ptr != '0');
527 len++;
528 }
529 if (*ptr)
530 len = 0; /* not ...~<number> */
531 else if (seen_nonzero)
532 early = 1;
533 else if (len == 1)
534 early = 1; /* "name~" is "name~1"! */
535 }
536 }
537 if (len) {
538 struct strbuf truname = STRBUF_INIT;
539 strbuf_addf(&truname, "refs/heads/%s", remote);
540 strbuf_setlen(&truname, truname.len - len);
541 if (ref_exists(truname.buf)) {
542 strbuf_addf(msg,
543 "%s\t\tbranch '%s'%s of .\n",
544 oid_to_hex(&remote_head->object.oid),
545 truname.buf + 11,
546 (early ? " (early part)" : ""));
547 strbuf_release(&truname);
548 goto cleanup;
549 }
550 strbuf_release(&truname);
551 }
552
553 desc = merge_remote_util(remote_head);
554 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
555 strbuf_addf(msg, "%s\t\t%s '%s'\n",
556 oid_to_hex(&desc->obj->oid),
557 type_name(desc->obj->type),
558 remote);
559 goto cleanup;
560 }
561
562 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
563 oid_to_hex(&remote_head->object.oid), remote);
564 cleanup:
565 strbuf_release(&buf);
566 strbuf_release(&bname);
567 }
568
569 static void parse_branch_merge_options(char *bmo)
570 {
571 const char **argv;
572 int argc;
573
574 if (!bmo)
575 return;
576 argc = split_cmdline(bmo, &argv);
577 if (argc < 0)
578 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
579 split_cmdline_strerror(argc));
580 REALLOC_ARRAY(argv, argc + 2);
581 MOVE_ARRAY(argv + 1, argv, argc + 1);
582 argc++;
583 argv[0] = "branch.*.mergeoptions";
584 parse_options(argc, argv, NULL, builtin_merge_options,
585 builtin_merge_usage, 0);
586 free(argv);
587 }
588
589 static int git_merge_config(const char *k, const char *v, void *cb)
590 {
591 int status;
592
593 if (branch && starts_with(k, "branch.") &&
594 starts_with(k + 7, branch) &&
595 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
596 free(branch_mergeoptions);
597 branch_mergeoptions = xstrdup(v);
598 return 0;
599 }
600
601 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
602 show_diffstat = git_config_bool(k, v);
603 else if (!strcmp(k, "merge.verifysignatures"))
604 verify_signatures = git_config_bool(k, v);
605 else if (!strcmp(k, "pull.twohead"))
606 return git_config_string(&pull_twohead, k, v);
607 else if (!strcmp(k, "pull.octopus"))
608 return git_config_string(&pull_octopus, k, v);
609 else if (!strcmp(k, "merge.renormalize"))
610 option_renormalize = git_config_bool(k, v);
611 else if (!strcmp(k, "merge.ff")) {
612 int boolval = git_parse_maybe_bool(v);
613 if (0 <= boolval) {
614 fast_forward = boolval ? FF_ALLOW : FF_NO;
615 } else if (v && !strcmp(v, "only")) {
616 fast_forward = FF_ONLY;
617 } /* do not barf on values from future versions of git */
618 return 0;
619 } else if (!strcmp(k, "merge.defaulttoupstream")) {
620 default_to_upstream = git_config_bool(k, v);
621 return 0;
622 } else if (!strcmp(k, "commit.gpgsign")) {
623 sign_commit = git_config_bool(k, v) ? "" : NULL;
624 return 0;
625 }
626
627 status = fmt_merge_msg_config(k, v, cb);
628 if (status)
629 return status;
630 status = git_gpg_config(k, v, NULL);
631 if (status)
632 return status;
633 return git_diff_ui_config(k, v, cb);
634 }
635
636 static int read_tree_trivial(struct object_id *common, struct object_id *head,
637 struct object_id *one)
638 {
639 int i, nr_trees = 0;
640 struct tree *trees[MAX_UNPACK_TREES];
641 struct tree_desc t[MAX_UNPACK_TREES];
642 struct unpack_trees_options opts;
643
644 memset(&opts, 0, sizeof(opts));
645 opts.head_idx = 2;
646 opts.src_index = &the_index;
647 opts.dst_index = &the_index;
648 opts.update = 1;
649 opts.verbose_update = 1;
650 opts.trivial_merges_only = 1;
651 opts.merge = 1;
652 trees[nr_trees] = parse_tree_indirect(common);
653 if (!trees[nr_trees++])
654 return -1;
655 trees[nr_trees] = parse_tree_indirect(head);
656 if (!trees[nr_trees++])
657 return -1;
658 trees[nr_trees] = parse_tree_indirect(one);
659 if (!trees[nr_trees++])
660 return -1;
661 opts.fn = threeway_merge;
662 cache_tree_free(&active_cache_tree);
663 for (i = 0; i < nr_trees; i++) {
664 parse_tree(trees[i]);
665 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
666 }
667 if (unpack_trees(nr_trees, t, &opts))
668 return -1;
669 return 0;
670 }
671
672 static void write_tree_trivial(struct object_id *oid)
673 {
674 if (write_cache_as_tree(oid, 0, NULL))
675 die(_("git write-tree failed to write a tree"));
676 }
677
678 static int try_merge_strategy(const char *strategy, struct commit_list *common,
679 struct commit_list *remoteheads,
680 struct commit *head)
681 {
682 struct lock_file lock = LOCK_INIT;
683 const char *head_arg = "HEAD";
684
685 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
686 refresh_cache(REFRESH_QUIET);
687 if (write_locked_index(&the_index, &lock,
688 COMMIT_LOCK | SKIP_IF_UNCHANGED))
689 return error(_("Unable to write index."));
690
691 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
692 int clean, x;
693 struct commit *result;
694 struct commit_list *reversed = NULL;
695 struct merge_options o;
696 struct commit_list *j;
697
698 if (remoteheads->next) {
699 error(_("Not handling anything other than two heads merge."));
700 return 2;
701 }
702
703 init_merge_options(&o);
704 if (!strcmp(strategy, "subtree"))
705 o.subtree_shift = "";
706
707 o.renormalize = option_renormalize;
708 o.show_rename_progress =
709 show_progress == -1 ? isatty(2) : show_progress;
710
711 for (x = 0; x < xopts_nr; x++)
712 if (parse_merge_opt(&o, xopts[x]))
713 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
714
715 o.branch1 = head_arg;
716 o.branch2 = merge_remote_util(remoteheads->item)->name;
717
718 for (j = common; j; j = j->next)
719 commit_list_insert(j->item, &reversed);
720
721 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
722 clean = merge_recursive(&o, head,
723 remoteheads->item, reversed, &result);
724 if (clean < 0)
725 exit(128);
726 if (write_locked_index(&the_index, &lock,
727 COMMIT_LOCK | SKIP_IF_UNCHANGED))
728 die(_("unable to write %s"), get_index_file());
729 return clean ? 0 : 1;
730 } else {
731 return try_merge_command(the_repository,
732 strategy, xopts_nr, xopts,
733 common, head_arg, remoteheads);
734 }
735 }
736
737 static void count_diff_files(struct diff_queue_struct *q,
738 struct diff_options *opt, void *data)
739 {
740 int *count = data;
741
742 (*count) += q->nr;
743 }
744
745 static int count_unmerged_entries(void)
746 {
747 int i, ret = 0;
748
749 for (i = 0; i < active_nr; i++)
750 if (ce_stage(active_cache[i]))
751 ret++;
752
753 return ret;
754 }
755
756 static void add_strategies(const char *string, unsigned attr)
757 {
758 int i;
759
760 if (string) {
761 struct string_list list = STRING_LIST_INIT_DUP;
762 struct string_list_item *item;
763 string_list_split(&list, string, ' ', -1);
764 for_each_string_list_item(item, &list)
765 append_strategy(get_strategy(item->string));
766 string_list_clear(&list, 0);
767 return;
768 }
769 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
770 if (all_strategy[i].attr & attr)
771 append_strategy(&all_strategy[i]);
772
773 }
774
775 static void read_merge_msg(struct strbuf *msg)
776 {
777 const char *filename = git_path_merge_msg(the_repository);
778 strbuf_reset(msg);
779 if (strbuf_read_file(msg, filename, 0) < 0)
780 die_errno(_("Could not read from '%s'"), filename);
781 }
782
783 static void write_merge_state(struct commit_list *);
784 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
785 {
786 if (err_msg)
787 error("%s", err_msg);
788 fprintf(stderr,
789 _("Not committing merge; use 'git commit' to complete the merge.\n"));
790 write_merge_state(remoteheads);
791 exit(1);
792 }
793
794 static const char merge_editor_comment[] =
795 N_("Please enter a commit message to explain why this merge is necessary,\n"
796 "especially if it merges an updated upstream into a topic branch.\n"
797 "\n"
798 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
799 "the commit.\n");
800
801 static void write_merge_heads(struct commit_list *);
802 static void prepare_to_commit(struct commit_list *remoteheads)
803 {
804 struct strbuf msg = STRBUF_INIT;
805 strbuf_addbuf(&msg, &merge_msg);
806 strbuf_addch(&msg, '\n');
807 if (squash)
808 BUG("the control must not reach here under --squash");
809 if (0 < option_edit)
810 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
811 if (signoff)
812 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
813 write_merge_heads(remoteheads);
814 write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
815 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
816 git_path_merge_msg(the_repository), "merge", NULL))
817 abort_commit(remoteheads, NULL);
818 if (0 < option_edit) {
819 if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
820 abort_commit(remoteheads, NULL);
821 }
822
823 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
824 "commit-msg",
825 git_path_merge_msg(the_repository), NULL))
826 abort_commit(remoteheads, NULL);
827
828 read_merge_msg(&msg);
829 strbuf_stripspace(&msg, 0 < option_edit);
830 if (!msg.len)
831 abort_commit(remoteheads, _("Empty commit message."));
832 strbuf_release(&merge_msg);
833 strbuf_addbuf(&merge_msg, &msg);
834 strbuf_release(&msg);
835 }
836
837 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
838 {
839 struct object_id result_tree, result_commit;
840 struct commit_list *parents, **pptr = &parents;
841 struct lock_file lock = LOCK_INIT;
842
843 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
844 refresh_cache(REFRESH_QUIET);
845 if (write_locked_index(&the_index, &lock,
846 COMMIT_LOCK | SKIP_IF_UNCHANGED))
847 return error(_("Unable to write index."));
848
849 write_tree_trivial(&result_tree);
850 printf(_("Wonderful.\n"));
851 pptr = commit_list_append(head, pptr);
852 pptr = commit_list_append(remoteheads->item, pptr);
853 prepare_to_commit(remoteheads);
854 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
855 &result_commit, NULL, sign_commit))
856 die(_("failed to write commit object"));
857 finish(head, remoteheads, &result_commit, "In-index merge");
858 drop_save();
859 return 0;
860 }
861
862 static int finish_automerge(struct commit *head,
863 int head_subsumed,
864 struct commit_list *common,
865 struct commit_list *remoteheads,
866 struct object_id *result_tree,
867 const char *wt_strategy)
868 {
869 struct commit_list *parents = NULL;
870 struct strbuf buf = STRBUF_INIT;
871 struct object_id result_commit;
872
873 free_commit_list(common);
874 parents = remoteheads;
875 if (!head_subsumed || fast_forward == FF_NO)
876 commit_list_insert(head, &parents);
877 strbuf_addch(&merge_msg, '\n');
878 prepare_to_commit(remoteheads);
879 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
880 &result_commit, NULL, sign_commit))
881 die(_("failed to write commit object"));
882 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
883 finish(head, remoteheads, &result_commit, buf.buf);
884 strbuf_release(&buf);
885 drop_save();
886 return 0;
887 }
888
889 static int suggest_conflicts(void)
890 {
891 const char *filename;
892 FILE *fp;
893 struct strbuf msgbuf = STRBUF_INIT;
894
895 filename = git_path_merge_msg(the_repository);
896 fp = xfopen(filename, "a");
897
898 append_conflicts_hint(&msgbuf);
899 fputs(msgbuf.buf, fp);
900 strbuf_release(&msgbuf);
901 fclose(fp);
902 rerere(allow_rerere_auto);
903 printf(_("Automatic merge failed; "
904 "fix conflicts and then commit the result.\n"));
905 return 1;
906 }
907
908 static int evaluate_result(void)
909 {
910 int cnt = 0;
911 struct rev_info rev;
912
913 /* Check how many files differ. */
914 init_revisions(&rev, "");
915 setup_revisions(0, NULL, &rev, NULL);
916 rev.diffopt.output_format |=
917 DIFF_FORMAT_CALLBACK;
918 rev.diffopt.format_callback = count_diff_files;
919 rev.diffopt.format_callback_data = &cnt;
920 run_diff_files(&rev, 0);
921
922 /*
923 * Check how many unmerged entries are
924 * there.
925 */
926 cnt += count_unmerged_entries();
927
928 return cnt;
929 }
930
931 /*
932 * Pretend as if the user told us to merge with the remote-tracking
933 * branch we have for the upstream of the current branch
934 */
935 static int setup_with_upstream(const char ***argv)
936 {
937 struct branch *branch = branch_get(NULL);
938 int i;
939 const char **args;
940
941 if (!branch)
942 die(_("No current branch."));
943 if (!branch->remote_name)
944 die(_("No remote for the current branch."));
945 if (!branch->merge_nr)
946 die(_("No default upstream defined for the current branch."));
947
948 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
949 for (i = 0; i < branch->merge_nr; i++) {
950 if (!branch->merge[i]->dst)
951 die(_("No remote-tracking branch for %s from %s"),
952 branch->merge[i]->src, branch->remote_name);
953 args[i] = branch->merge[i]->dst;
954 }
955 args[i] = NULL;
956 *argv = args;
957 return i;
958 }
959
960 static void write_merge_heads(struct commit_list *remoteheads)
961 {
962 struct commit_list *j;
963 struct strbuf buf = STRBUF_INIT;
964
965 for (j = remoteheads; j; j = j->next) {
966 struct object_id *oid;
967 struct commit *c = j->item;
968 struct merge_remote_desc *desc;
969
970 desc = merge_remote_util(c);
971 if (desc && desc->obj) {
972 oid = &desc->obj->oid;
973 } else {
974 oid = &c->object.oid;
975 }
976 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
977 }
978 write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len);
979
980 strbuf_reset(&buf);
981 if (fast_forward == FF_NO)
982 strbuf_addstr(&buf, "no-ff");
983 write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len);
984 strbuf_release(&buf);
985 }
986
987 static void write_merge_state(struct commit_list *remoteheads)
988 {
989 write_merge_heads(remoteheads);
990 strbuf_addch(&merge_msg, '\n');
991 write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf,
992 merge_msg.len);
993 }
994
995 static int default_edit_option(void)
996 {
997 static const char name[] = "GIT_MERGE_AUTOEDIT";
998 const char *e = getenv(name);
999 struct stat st_stdin, st_stdout;
1000
1001 if (have_message)
1002 /* an explicit -m msg without --[no-]edit */
1003 return 0;
1004
1005 if (e) {
1006 int v = git_parse_maybe_bool(e);
1007 if (v < 0)
1008 die(_("Bad value '%s' in environment '%s'"), e, name);
1009 return v;
1010 }
1011
1012 /* Use editor if stdin and stdout are the same and is a tty */
1013 return (!fstat(0, &st_stdin) &&
1014 !fstat(1, &st_stdout) &&
1015 isatty(0) && isatty(1) &&
1016 st_stdin.st_dev == st_stdout.st_dev &&
1017 st_stdin.st_ino == st_stdout.st_ino &&
1018 st_stdin.st_mode == st_stdout.st_mode);
1019 }
1020
1021 static struct commit_list *reduce_parents(struct commit *head_commit,
1022 int *head_subsumed,
1023 struct commit_list *remoteheads)
1024 {
1025 struct commit_list *parents, **remotes;
1026
1027 /*
1028 * Is the current HEAD reachable from another commit being
1029 * merged? If so we do not want to record it as a parent of
1030 * the resulting merge, unless --no-ff is given. We will flip
1031 * this variable to 0 when we find HEAD among the independent
1032 * tips being merged.
1033 */
1034 *head_subsumed = 1;
1035
1036 /* Find what parents to record by checking independent ones. */
1037 parents = reduce_heads(remoteheads);
1038 free_commit_list(remoteheads);
1039
1040 remoteheads = NULL;
1041 remotes = &remoteheads;
1042 while (parents) {
1043 struct commit *commit = pop_commit(&parents);
1044 if (commit == head_commit)
1045 *head_subsumed = 0;
1046 else
1047 remotes = &commit_list_insert(commit, remotes)->next;
1048 }
1049 return remoteheads;
1050 }
1051
1052 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1053 {
1054 struct fmt_merge_msg_opts opts;
1055
1056 memset(&opts, 0, sizeof(opts));
1057 opts.add_title = !have_message;
1058 opts.shortlog_len = shortlog_len;
1059 opts.credit_people = (0 < option_edit);
1060
1061 fmt_merge_msg(merge_names, merge_msg, &opts);
1062 if (merge_msg->len)
1063 strbuf_setlen(merge_msg, merge_msg->len - 1);
1064 }
1065
1066 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1067 {
1068 const char *filename;
1069 int fd, pos, npos;
1070 struct strbuf fetch_head_file = STRBUF_INIT;
1071 const unsigned hexsz = the_hash_algo->hexsz;
1072
1073 if (!merge_names)
1074 merge_names = &fetch_head_file;
1075
1076 filename = git_path_fetch_head(the_repository);
1077 fd = open(filename, O_RDONLY);
1078 if (fd < 0)
1079 die_errno(_("could not open '%s' for reading"), filename);
1080
1081 if (strbuf_read(merge_names, fd, 0) < 0)
1082 die_errno(_("could not read '%s'"), filename);
1083 if (close(fd) < 0)
1084 die_errno(_("could not close '%s'"), filename);
1085
1086 for (pos = 0; pos < merge_names->len; pos = npos) {
1087 struct object_id oid;
1088 char *ptr;
1089 struct commit *commit;
1090
1091 ptr = strchr(merge_names->buf + pos, '\n');
1092 if (ptr)
1093 npos = ptr - merge_names->buf + 1;
1094 else
1095 npos = merge_names->len;
1096
1097 if (npos - pos < hexsz + 2 ||
1098 get_oid_hex(merge_names->buf + pos, &oid))
1099 commit = NULL; /* bad */
1100 else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2))
1101 continue; /* not-for-merge */
1102 else {
1103 char saved = merge_names->buf[pos + hexsz];
1104 merge_names->buf[pos + hexsz] = '\0';
1105 commit = get_merge_parent(merge_names->buf + pos);
1106 merge_names->buf[pos + hexsz] = saved;
1107 }
1108 if (!commit) {
1109 if (ptr)
1110 *ptr = '\0';
1111 die(_("not something we can merge in %s: %s"),
1112 filename, merge_names->buf + pos);
1113 }
1114 remotes = &commit_list_insert(commit, remotes)->next;
1115 }
1116
1117 if (merge_names == &fetch_head_file)
1118 strbuf_release(&fetch_head_file);
1119 }
1120
1121 static struct commit_list *collect_parents(struct commit *head_commit,
1122 int *head_subsumed,
1123 int argc, const char **argv,
1124 struct strbuf *merge_msg)
1125 {
1126 int i;
1127 struct commit_list *remoteheads = NULL;
1128 struct commit_list **remotes = &remoteheads;
1129 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1130
1131 if (merge_msg && (!have_message || shortlog_len))
1132 autogen = &merge_names;
1133
1134 if (head_commit)
1135 remotes = &commit_list_insert(head_commit, remotes)->next;
1136
1137 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1138 handle_fetch_head(remotes, autogen);
1139 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1140 } else {
1141 for (i = 0; i < argc; i++) {
1142 struct commit *commit = get_merge_parent(argv[i]);
1143 if (!commit)
1144 help_unknown_ref(argv[i], "merge",
1145 _("not something we can merge"));
1146 remotes = &commit_list_insert(commit, remotes)->next;
1147 }
1148 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1149 if (autogen) {
1150 struct commit_list *p;
1151 for (p = remoteheads; p; p = p->next)
1152 merge_name(merge_remote_util(p->item)->name, autogen);
1153 }
1154 }
1155
1156 if (autogen) {
1157 prepare_merge_message(autogen, merge_msg);
1158 strbuf_release(autogen);
1159 }
1160
1161 return remoteheads;
1162 }
1163
1164 static int merging_a_throwaway_tag(struct commit *commit)
1165 {
1166 char *tag_ref;
1167 struct object_id oid;
1168 int is_throwaway_tag = 0;
1169
1170 /* Are we merging a tag? */
1171 if (!merge_remote_util(commit) ||
1172 !merge_remote_util(commit)->obj ||
1173 merge_remote_util(commit)->obj->type != OBJ_TAG)
1174 return is_throwaway_tag;
1175
1176 /*
1177 * Now we know we are merging a tag object. Are we downstream
1178 * and following the tags from upstream? If so, we must have
1179 * the tag object pointed at by "refs/tags/$T" where $T is the
1180 * tagname recorded in the tag object. We want to allow such
1181 * a "just to catch up" merge to fast-forward.
1182 *
1183 * Otherwise, we are playing an integrator's role, making a
1184 * merge with a throw-away tag from a contributor with
1185 * something like "git pull $contributor $signed_tag".
1186 * We want to forbid such a merge from fast-forwarding
1187 * by default; otherwise we would not keep the signature
1188 * anywhere.
1189 */
1190 tag_ref = xstrfmt("refs/tags/%s",
1191 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1192 if (!read_ref(tag_ref, &oid) &&
1193 !oidcmp(&oid, &merge_remote_util(commit)->obj->oid))
1194 is_throwaway_tag = 0;
1195 else
1196 is_throwaway_tag = 1;
1197 free(tag_ref);
1198 return is_throwaway_tag;
1199 }
1200
1201 int cmd_merge(int argc, const char **argv, const char *prefix)
1202 {
1203 struct object_id result_tree, stash, head_oid;
1204 struct commit *head_commit;
1205 struct strbuf buf = STRBUF_INIT;
1206 int i, ret = 0, head_subsumed;
1207 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1208 struct commit_list *common = NULL;
1209 const char *best_strategy = NULL, *wt_strategy = NULL;
1210 struct commit_list *remoteheads, *p;
1211 void *branch_to_free;
1212 int orig_argc = argc;
1213
1214 if (argc == 2 && !strcmp(argv[1], "-h"))
1215 usage_with_options(builtin_merge_usage, builtin_merge_options);
1216
1217 /*
1218 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1219 * current branch.
1220 */
1221 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1222 if (branch)
1223 skip_prefix(branch, "refs/heads/", &branch);
1224
1225 init_diff_ui_defaults();
1226 git_config(git_merge_config, NULL);
1227
1228 if (!branch || is_null_oid(&head_oid))
1229 head_commit = NULL;
1230 else
1231 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1232
1233 if (branch_mergeoptions)
1234 parse_branch_merge_options(branch_mergeoptions);
1235 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1236 builtin_merge_usage, 0);
1237 if (shortlog_len < 0)
1238 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1239
1240 if (verbosity < 0 && show_progress == -1)
1241 show_progress = 0;
1242
1243 if (abort_current_merge) {
1244 int nargc = 2;
1245 const char *nargv[] = {"reset", "--merge", NULL};
1246
1247 if (orig_argc != 2)
1248 usage_msg_opt(_("--abort expects no arguments"),
1249 builtin_merge_usage, builtin_merge_options);
1250
1251 if (!file_exists(git_path_merge_head(the_repository)))
1252 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1253
1254 /* Invoke 'git reset --merge' */
1255 ret = cmd_reset(nargc, nargv, prefix);
1256 goto done;
1257 }
1258
1259 if (continue_current_merge) {
1260 int nargc = 1;
1261 const char *nargv[] = {"commit", NULL};
1262
1263 if (orig_argc != 2)
1264 usage_msg_opt(_("--continue expects no arguments"),
1265 builtin_merge_usage, builtin_merge_options);
1266
1267 if (!file_exists(git_path_merge_head(the_repository)))
1268 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1269
1270 /* Invoke 'git commit' */
1271 ret = cmd_commit(nargc, nargv, prefix);
1272 goto done;
1273 }
1274
1275 if (read_cache_unmerged())
1276 die_resolve_conflict("merge");
1277
1278 if (file_exists(git_path_merge_head(the_repository))) {
1279 /*
1280 * There is no unmerged entry, don't advise 'git
1281 * add/rm <file>', just 'git commit'.
1282 */
1283 if (advice_resolve_conflict)
1284 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1285 "Please, commit your changes before you merge."));
1286 else
1287 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1288 }
1289 if (file_exists(git_path_cherry_pick_head(the_repository))) {
1290 if (advice_resolve_conflict)
1291 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1292 "Please, commit your changes before you merge."));
1293 else
1294 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1295 }
1296 resolve_undo_clear();
1297
1298 if (verbosity < 0)
1299 show_diffstat = 0;
1300
1301 if (squash) {
1302 if (fast_forward == FF_NO)
1303 die(_("You cannot combine --squash with --no-ff."));
1304 option_commit = 0;
1305 }
1306
1307 if (!argc) {
1308 if (default_to_upstream)
1309 argc = setup_with_upstream(&argv);
1310 else
1311 die(_("No commit specified and merge.defaultToUpstream not set."));
1312 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1313 argv[0] = "@{-1}";
1314 }
1315
1316 if (!argc)
1317 usage_with_options(builtin_merge_usage,
1318 builtin_merge_options);
1319
1320 if (!head_commit) {
1321 /*
1322 * If the merged head is a valid one there is no reason
1323 * to forbid "git merge" into a branch yet to be born.
1324 * We do the same for "git pull".
1325 */
1326 struct object_id *remote_head_oid;
1327 if (squash)
1328 die(_("Squash commit into empty head not supported yet"));
1329 if (fast_forward == FF_NO)
1330 die(_("Non-fast-forward commit does not make sense into "
1331 "an empty head"));
1332 remoteheads = collect_parents(head_commit, &head_subsumed,
1333 argc, argv, NULL);
1334 if (!remoteheads)
1335 die(_("%s - not something we can merge"), argv[0]);
1336 if (remoteheads->next)
1337 die(_("Can merge only exactly one commit into empty head"));
1338 remote_head_oid = &remoteheads->item->object.oid;
1339 read_empty(remote_head_oid, 0);
1340 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1341 UPDATE_REFS_DIE_ON_ERR);
1342 goto done;
1343 }
1344
1345 /*
1346 * All the rest are the commits being merged; prepare
1347 * the standard merge summary message to be appended
1348 * to the given message.
1349 */
1350 remoteheads = collect_parents(head_commit, &head_subsumed,
1351 argc, argv, &merge_msg);
1352
1353 if (!head_commit || !argc)
1354 usage_with_options(builtin_merge_usage,
1355 builtin_merge_options);
1356
1357 if (verify_signatures) {
1358 for (p = remoteheads; p; p = p->next) {
1359 struct commit *commit = p->item;
1360 char hex[GIT_MAX_HEXSZ + 1];
1361 struct signature_check signature_check;
1362 memset(&signature_check, 0, sizeof(signature_check));
1363
1364 check_commit_signature(commit, &signature_check);
1365
1366 find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1367 switch (signature_check.result) {
1368 case 'G':
1369 break;
1370 case 'U':
1371 die(_("Commit %s has an untrusted GPG signature, "
1372 "allegedly by %s."), hex, signature_check.signer);
1373 case 'B':
1374 die(_("Commit %s has a bad GPG signature "
1375 "allegedly by %s."), hex, signature_check.signer);
1376 default: /* 'N' */
1377 die(_("Commit %s does not have a GPG signature."), hex);
1378 }
1379 if (verbosity >= 0 && signature_check.result == 'G')
1380 printf(_("Commit %s has a good GPG signature by %s\n"),
1381 hex, signature_check.signer);
1382
1383 signature_check_clear(&signature_check);
1384 }
1385 }
1386
1387 strbuf_addstr(&buf, "merge");
1388 for (p = remoteheads; p; p = p->next)
1389 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1390 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1391 strbuf_reset(&buf);
1392
1393 for (p = remoteheads; p; p = p->next) {
1394 struct commit *commit = p->item;
1395 strbuf_addf(&buf, "GITHEAD_%s",
1396 oid_to_hex(&commit->object.oid));
1397 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1398 strbuf_reset(&buf);
1399 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1400 fast_forward = FF_NO;
1401 }
1402
1403 if (option_edit < 0)
1404 option_edit = default_edit_option();
1405
1406 if (!use_strategies) {
1407 if (!remoteheads)
1408 ; /* already up-to-date */
1409 else if (!remoteheads->next)
1410 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1411 else
1412 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1413 }
1414
1415 for (i = 0; i < use_strategies_nr; i++) {
1416 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1417 fast_forward = FF_NO;
1418 if (use_strategies[i]->attr & NO_TRIVIAL)
1419 allow_trivial = 0;
1420 }
1421
1422 if (!remoteheads)
1423 ; /* already up-to-date */
1424 else if (!remoteheads->next)
1425 common = get_merge_bases(head_commit, remoteheads->item);
1426 else {
1427 struct commit_list *list = remoteheads;
1428 commit_list_insert(head_commit, &list);
1429 common = get_octopus_merge_bases(list);
1430 free(list);
1431 }
1432
1433 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1434 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1435
1436 if (remoteheads && !common) {
1437 /* No common ancestors found. */
1438 if (!allow_unrelated_histories)
1439 die(_("refusing to merge unrelated histories"));
1440 /* otherwise, we need a real merge. */
1441 } else if (!remoteheads ||
1442 (!remoteheads->next && !common->next &&
1443 common->item == remoteheads->item)) {
1444 /*
1445 * If head can reach all the merge then we are up to date.
1446 * but first the most common case of merging one remote.
1447 */
1448 finish_up_to_date(_("Already up to date."));
1449 goto done;
1450 } else if (fast_forward != FF_NO && !remoteheads->next &&
1451 !common->next &&
1452 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1453 /* Again the most common case of merging one remote. */
1454 struct strbuf msg = STRBUF_INIT;
1455 struct commit *commit;
1456
1457 if (verbosity >= 0) {
1458 printf(_("Updating %s..%s\n"),
1459 find_unique_abbrev(&head_commit->object.oid,
1460 DEFAULT_ABBREV),
1461 find_unique_abbrev(&remoteheads->item->object.oid,
1462 DEFAULT_ABBREV));
1463 }
1464 strbuf_addstr(&msg, "Fast-forward");
1465 if (have_message)
1466 strbuf_addstr(&msg,
1467 " (no commit created; -m option ignored)");
1468 commit = remoteheads->item;
1469 if (!commit) {
1470 ret = 1;
1471 goto done;
1472 }
1473
1474 if (checkout_fast_forward(the_repository,
1475 &head_commit->object.oid,
1476 &commit->object.oid,
1477 overwrite_ignore)) {
1478 ret = 1;
1479 goto done;
1480 }
1481
1482 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1483 drop_save();
1484 goto done;
1485 } else if (!remoteheads->next && common->next)
1486 ;
1487 /*
1488 * We are not doing octopus and not fast-forward. Need
1489 * a real merge.
1490 */
1491 else if (!remoteheads->next && !common->next && option_commit) {
1492 /*
1493 * We are not doing octopus, not fast-forward, and have
1494 * only one common.
1495 */
1496 refresh_cache(REFRESH_QUIET);
1497 if (allow_trivial && fast_forward != FF_ONLY) {
1498 /* See if it is really trivial. */
1499 git_committer_info(IDENT_STRICT);
1500 printf(_("Trying really trivial in-index merge...\n"));
1501 if (!read_tree_trivial(&common->item->object.oid,
1502 &head_commit->object.oid,
1503 &remoteheads->item->object.oid)) {
1504 ret = merge_trivial(head_commit, remoteheads);
1505 goto done;
1506 }
1507 printf(_("Nope.\n"));
1508 }
1509 } else {
1510 /*
1511 * An octopus. If we can reach all the remote we are up
1512 * to date.
1513 */
1514 int up_to_date = 1;
1515 struct commit_list *j;
1516
1517 for (j = remoteheads; j; j = j->next) {
1518 struct commit_list *common_one;
1519
1520 /*
1521 * Here we *have* to calculate the individual
1522 * merge_bases again, otherwise "git merge HEAD^
1523 * HEAD^^" would be missed.
1524 */
1525 common_one = get_merge_bases(head_commit, j->item);
1526 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1527 up_to_date = 0;
1528 break;
1529 }
1530 }
1531 if (up_to_date) {
1532 finish_up_to_date(_("Already up to date. Yeeah!"));
1533 goto done;
1534 }
1535 }
1536
1537 if (fast_forward == FF_ONLY)
1538 die(_("Not possible to fast-forward, aborting."));
1539
1540 /* We are going to make a new commit. */
1541 git_committer_info(IDENT_STRICT);
1542
1543 /*
1544 * At this point, we need a real merge. No matter what strategy
1545 * we use, it would operate on the index, possibly affecting the
1546 * working tree, and when resolved cleanly, have the desired
1547 * tree in the index -- this means that the index must be in
1548 * sync with the head commit. The strategies are responsible
1549 * to ensure this.
1550 */
1551 if (use_strategies_nr == 1 ||
1552 /*
1553 * Stash away the local changes so that we can try more than one.
1554 */
1555 save_state(&stash))
1556 oidclr(&stash);
1557
1558 for (i = 0; i < use_strategies_nr; i++) {
1559 int ret;
1560 if (i) {
1561 printf(_("Rewinding the tree to pristine...\n"));
1562 restore_state(&head_commit->object.oid, &stash);
1563 }
1564 if (use_strategies_nr != 1)
1565 printf(_("Trying merge strategy %s...\n"),
1566 use_strategies[i]->name);
1567 /*
1568 * Remember which strategy left the state in the working
1569 * tree.
1570 */
1571 wt_strategy = use_strategies[i]->name;
1572
1573 ret = try_merge_strategy(use_strategies[i]->name,
1574 common, remoteheads,
1575 head_commit);
1576 if (!option_commit && !ret) {
1577 merge_was_ok = 1;
1578 /*
1579 * This is necessary here just to avoid writing
1580 * the tree, but later we will *not* exit with
1581 * status code 1 because merge_was_ok is set.
1582 */
1583 ret = 1;
1584 }
1585
1586 if (ret) {
1587 /*
1588 * The backend exits with 1 when conflicts are
1589 * left to be resolved, with 2 when it does not
1590 * handle the given merge at all.
1591 */
1592 if (ret == 1) {
1593 int cnt = evaluate_result();
1594
1595 if (best_cnt <= 0 || cnt <= best_cnt) {
1596 best_strategy = use_strategies[i]->name;
1597 best_cnt = cnt;
1598 }
1599 }
1600 if (merge_was_ok)
1601 break;
1602 else
1603 continue;
1604 }
1605
1606 /* Automerge succeeded. */
1607 write_tree_trivial(&result_tree);
1608 automerge_was_ok = 1;
1609 break;
1610 }
1611
1612 /*
1613 * If we have a resulting tree, that means the strategy module
1614 * auto resolved the merge cleanly.
1615 */
1616 if (automerge_was_ok) {
1617 ret = finish_automerge(head_commit, head_subsumed,
1618 common, remoteheads,
1619 &result_tree, wt_strategy);
1620 goto done;
1621 }
1622
1623 /*
1624 * Pick the result from the best strategy and have the user fix
1625 * it up.
1626 */
1627 if (!best_strategy) {
1628 restore_state(&head_commit->object.oid, &stash);
1629 if (use_strategies_nr > 1)
1630 fprintf(stderr,
1631 _("No merge strategy handled the merge.\n"));
1632 else
1633 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1634 use_strategies[0]->name);
1635 ret = 2;
1636 goto done;
1637 } else if (best_strategy == wt_strategy)
1638 ; /* We already have its result in the working tree. */
1639 else {
1640 printf(_("Rewinding the tree to pristine...\n"));
1641 restore_state(&head_commit->object.oid, &stash);
1642 printf(_("Using the %s to prepare resolving by hand.\n"),
1643 best_strategy);
1644 try_merge_strategy(best_strategy, common, remoteheads,
1645 head_commit);
1646 }
1647
1648 if (squash)
1649 finish(head_commit, remoteheads, NULL, NULL);
1650 else
1651 write_merge_state(remoteheads);
1652
1653 if (merge_was_ok)
1654 fprintf(stderr, _("Automatic merge went well; "
1655 "stopped before committing as requested\n"));
1656 else
1657 ret = suggest_conflicts();
1658
1659 done:
1660 free(branch_to_free);
1661 return ret;
1662 }