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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 #define USE_THE_REPOSITORY_VARIABLE
10 #define DISABLE_SIGN_COMPARE_WARNINGS
11
12 #include "builtin.h"
13
14 #include "abspath.h"
15 #include "advice.h"
16 #include "config.h"
17 #include "editor.h"
18 #include "environment.h"
19 #include "gettext.h"
20 #include "hex.h"
21 #include "object-name.h"
22 #include "parse-options.h"
23 #include "lockfile.h"
24 #include "repository.h"
25 #include "run-command.h"
26 #include "hook.h"
27 #include "diff.h"
28 #include "diff-merges.h"
29 #include "refs.h"
30 #include "refspec.h"
31 #include "commit.h"
32 #include "diffcore.h"
33 #include "path.h"
34 #include "revision.h"
35 #include "unpack-trees.h"
36 #include "cache-tree.h"
37 #include "dir.h"
38 #include "color.h"
39 #include "rerere.h"
40 #include "help.h"
41 #include "merge.h"
42 #include "merge-ort-wrappers.h"
43 #include "resolve-undo.h"
44 #include "remote.h"
45 #include "fmt-merge-msg.h"
46 #include "sequencer.h"
47 #include "string-list.h"
48 #include "tag.h"
49 #include "alias.h"
50 #include "branch.h"
51 #include "commit-reach.h"
52 #include "wt-status.h"
53 #include "commit-graph.h"
54
55 #define DEFAULT_TWOHEAD (1<<0)
56 #define DEFAULT_OCTOPUS (1<<1)
57 #define NO_FAST_FORWARD (1<<2)
58 #define NO_TRIVIAL (1<<3)
59
60 struct strategy {
61 const char *name;
62 unsigned attr;
63 };
64
65 static const char * const builtin_merge_usage[] = {
66 N_("git merge [<options>] [<commit>...]"),
67 "git merge --abort",
68 "git merge --continue",
69 NULL
70 };
71
72 #define MERGE_SHOW_DIFFSTAT 1
73 #define MERGE_SHOW_COMPACTSUMMARY 2
74
75 static int show_diffstat = MERGE_SHOW_DIFFSTAT, shortlog_len = -1, squash;
76 static int option_commit = -1;
77 static int option_edit = -1;
78 static int allow_trivial = 1, have_message, verify_signatures;
79 static int check_trust_level = 1;
80 static int overwrite_ignore = 1;
81 static struct strbuf merge_msg = STRBUF_INIT;
82 static struct strategy **use_strategies;
83 static size_t use_strategies_nr, use_strategies_alloc;
84 static struct strvec xopts = STRVEC_INIT;
85 static const char *branch;
86 static char *branch_mergeoptions;
87 static int verbosity;
88 static int allow_rerere_auto;
89 static int abort_current_merge;
90 static int quit_current_merge;
91 static int continue_current_merge;
92 static int allow_unrelated_histories;
93 static int show_progress = -1;
94 static int default_to_upstream = 1;
95 static int signoff;
96 static const char *sign_commit;
97 static int autostash;
98 static int no_verify;
99 static char *into_name;
100
101 static struct strategy all_strategy[] = {
102 { "recursive", NO_TRIVIAL },
103 { "octopus", DEFAULT_OCTOPUS },
104 { "ort", DEFAULT_TWOHEAD | NO_TRIVIAL },
105 { "resolve", 0 },
106 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
107 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
108 };
109
110 static char *pull_twohead, *pull_octopus;
111
112 enum ff_type {
113 FF_NO,
114 FF_ALLOW,
115 FF_ONLY
116 };
117
118 static enum ff_type fast_forward = FF_ALLOW;
119
120 static char *cleanup_arg;
121 static enum commit_msg_cleanup_mode cleanup_mode;
122
123 static int option_parse_message(const struct option *opt,
124 const char *arg, int unset)
125 {
126 struct strbuf *buf = opt->value;
127
128 if (unset)
129 strbuf_setlen(buf, 0);
130 else if (arg) {
131 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
132 have_message = 1;
133 } else
134 return error(_("switch `m' requires a value"));
135 return 0;
136 }
137
138 static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx,
139 const struct option *opt,
140 const char *arg_not_used,
141 int unset)
142 {
143 struct strbuf *buf = opt->value;
144 const char *arg;
145
146 BUG_ON_OPT_ARG(arg_not_used);
147 if (unset)
148 BUG("-F cannot be negated");
149
150 if (ctx->opt) {
151 arg = ctx->opt;
152 ctx->opt = NULL;
153 } else if (ctx->argc > 1) {
154 ctx->argc--;
155 arg = *++ctx->argv;
156 } else
157 return error(_("option `%s' requires a value"), opt->long_name);
158
159 if (buf->len)
160 strbuf_addch(buf, '\n');
161 if (ctx->prefix && !is_absolute_path(arg))
162 arg = prefix_filename(ctx->prefix, arg);
163 if (strbuf_read_file(buf, arg, 0) < 0)
164 return error(_("could not read file '%s'"), arg);
165 have_message = 1;
166
167 return 0;
168 }
169
170 static struct strategy *get_strategy(const char *name)
171 {
172 int i;
173 struct strategy *ret;
174 static struct cmdnames main_cmds = {0}, other_cmds = {0};
175 static int loaded;
176 char *default_strategy = NULL;
177
178 if (!name)
179 return NULL;
180
181 if (default_strategy &&
182 !strcmp(default_strategy, "ort") &&
183 !strcmp(name, "recursive")) {
184 name = "ort";
185 }
186
187 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
188 if (!strcmp(name, all_strategy[i].name))
189 return &all_strategy[i];
190
191 if (!loaded) {
192 struct cmdnames not_strategies = {0};
193 loaded = 1;
194
195 load_command_list("git-merge-", &main_cmds, &other_cmds);
196 for (i = 0; i < main_cmds.cnt; i++) {
197 int j, found = 0;
198 struct cmdname *ent = main_cmds.names[i];
199 for (j = 0; !found && j < ARRAY_SIZE(all_strategy); j++)
200 if (!xstrncmpz(all_strategy[j].name, ent->name, ent->len))
201 found = 1;
202 if (!found)
203 add_cmdname(&not_strategies, ent->name, ent->len);
204 }
205 exclude_cmds(&main_cmds, &not_strategies);
206
207 cmdnames_release(&not_strategies);
208 }
209 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
210 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
211 fprintf(stderr, _("Available strategies are:"));
212 for (i = 0; i < main_cmds.cnt; i++)
213 fprintf(stderr, " %s", main_cmds.names[i]->name);
214 fprintf(stderr, ".\n");
215 if (other_cmds.cnt) {
216 fprintf(stderr, _("Available custom strategies are:"));
217 for (i = 0; i < other_cmds.cnt; i++)
218 fprintf(stderr, " %s", other_cmds.names[i]->name);
219 fprintf(stderr, ".\n");
220 }
221 exit(1);
222 }
223
224 CALLOC_ARRAY(ret, 1);
225 ret->name = xstrdup(name);
226 ret->attr = NO_TRIVIAL;
227
228 cmdnames_release(&main_cmds);
229 cmdnames_release(&other_cmds);
230 return ret;
231 }
232
233 static void append_strategy(struct strategy *s)
234 {
235 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
236 use_strategies[use_strategies_nr++] = s;
237 }
238
239 static int option_parse_strategy(const struct option *opt UNUSED,
240 const char *name, int unset)
241 {
242 if (unset)
243 return 0;
244
245 append_strategy(get_strategy(name));
246 return 0;
247 }
248
249 static int option_parse_compact_summary(const struct option *opt,
250 const char *name UNUSED, int unset)
251 {
252 int *setting = opt->value;
253
254 if (unset)
255 *setting = 0;
256 else
257 *setting = MERGE_SHOW_COMPACTSUMMARY;
258 return 0;
259 }
260
261 static struct option builtin_merge_options[] = {
262 OPT_SET_INT('n', NULL, &show_diffstat,
263 N_("do not show a diffstat at the end of the merge"), 0),
264 OPT_BOOL(0, "stat", &show_diffstat,
265 N_("show a diffstat at the end of the merge")),
266 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
267 OPT_CALLBACK_F(0, "compact-summary", &show_diffstat, NULL,
268 N_("show a compact-summary at the end of the merge"),
269 PARSE_OPT_NOARG,
270 option_parse_compact_summary),
271 {
272 .type = OPTION_INTEGER,
273 .long_name = "log",
274 .value = &shortlog_len,
275 .precision = sizeof(shortlog_len),
276 .argh = N_("n"),
277 .help = N_("add (at most <n>) entries from shortlog to merge commit message"),
278 .flags = PARSE_OPT_OPTARG,
279 .defval = DEFAULT_MERGE_LOG_LEN,
280 },
281 OPT_BOOL(0, "squash", &squash,
282 N_("create a single commit instead of doing a merge")),
283 OPT_BOOL(0, "commit", &option_commit,
284 N_("perform a commit if the merge succeeds (default)")),
285 OPT_BOOL('e', "edit", &option_edit,
286 N_("edit message before committing")),
287 OPT_CLEANUP(&cleanup_arg),
288 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
289 OPT_SET_INT_F(0, "ff-only", &fast_forward,
290 N_("abort if fast-forward is not possible"),
291 FF_ONLY, PARSE_OPT_NONEG),
292 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
293 OPT_BOOL(0, "verify-signatures", &verify_signatures,
294 N_("verify that the named commit has a valid GPG signature")),
295 OPT_CALLBACK('s', "strategy", NULL, N_("strategy"),
296 N_("merge strategy to use"), option_parse_strategy),
297 OPT_STRVEC('X', "strategy-option", &xopts, N_("option=value"),
298 N_("option for selected merge strategy")),
299 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
300 N_("merge commit message (for a non-fast-forward merge)"),
301 option_parse_message),
302 {
303 .type = OPTION_LOWLEVEL_CALLBACK,
304 .short_name = 'F',
305 .long_name = "file",
306 .value = &merge_msg,
307 .argh = N_("path"),
308 .help = N_("read message from file"),
309 .flags = PARSE_OPT_NONEG,
310 .ll_callback = option_read_message,
311 },
312 OPT_STRING(0, "into-name", &into_name, N_("name"),
313 N_("use <name> instead of the real target")),
314 OPT__VERBOSITY(&verbosity),
315 OPT_BOOL(0, "abort", &abort_current_merge,
316 N_("abort the current in-progress merge")),
317 OPT_BOOL(0, "quit", &quit_current_merge,
318 N_("--abort but leave index and working tree alone")),
319 OPT_BOOL(0, "continue", &continue_current_merge,
320 N_("continue the current in-progress merge")),
321 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
322 N_("allow merging unrelated histories")),
323 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
324 {
325 .type = OPTION_STRING,
326 .short_name = 'S',
327 .long_name = "gpg-sign",
328 .value = &sign_commit,
329 .argh = N_("key-id"),
330 .help = N_("GPG sign commit"),
331 .flags = PARSE_OPT_OPTARG,
332 .defval = (intptr_t) "",
333 },
334 OPT_AUTOSTASH(&autostash),
335 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
336 OPT_BOOL(0, "signoff", &signoff, N_("add a Signed-off-by trailer")),
337 OPT_BOOL(0, "no-verify", &no_verify, N_("bypass pre-merge-commit and commit-msg hooks")),
338 OPT_END()
339 };
340
341 static int save_state(struct object_id *stash)
342 {
343 int len;
344 struct child_process cp = CHILD_PROCESS_INIT;
345 struct strbuf buffer = STRBUF_INIT;
346 struct lock_file lock_file = LOCK_INIT;
347 int fd;
348 int rc = -1;
349
350 fd = repo_hold_locked_index(the_repository, &lock_file, 0);
351 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL, NULL);
352 if (0 <= fd)
353 repo_update_index_if_able(the_repository, &lock_file);
354 rollback_lock_file(&lock_file);
355
356 strvec_pushl(&cp.args, "stash", "create", NULL);
357 cp.out = -1;
358 cp.git_cmd = 1;
359
360 if (start_command(&cp))
361 die(_("could not run stash."));
362 len = strbuf_read(&buffer, cp.out, 1024);
363 close(cp.out);
364
365 if (finish_command(&cp) || len < 0)
366 die(_("stash failed"));
367 else if (!len) /* no changes */
368 goto out;
369 strbuf_setlen(&buffer, buffer.len-1);
370 if (repo_get_oid(the_repository, buffer.buf, stash))
371 die(_("not a valid object: %s"), buffer.buf);
372 rc = 0;
373 out:
374 strbuf_release(&buffer);
375 return rc;
376 }
377
378 static void read_empty(const struct object_id *oid)
379 {
380 struct child_process cmd = CHILD_PROCESS_INIT;
381
382 strvec_pushl(&cmd.args, "read-tree", "-m", "-u",
383 empty_tree_oid_hex(the_repository->hash_algo),
384 oid_to_hex(oid), NULL);
385 cmd.git_cmd = 1;
386
387 if (run_command(&cmd))
388 die(_("read-tree failed"));
389 }
390
391 static void reset_hard(const struct object_id *oid)
392 {
393 struct child_process cmd = CHILD_PROCESS_INIT;
394
395 strvec_pushl(&cmd.args, "read-tree", "-v", "--reset", "-u",
396 oid_to_hex(oid), NULL);
397 cmd.git_cmd = 1;
398
399 if (run_command(&cmd))
400 die(_("read-tree failed"));
401 }
402
403 static void restore_state(const struct object_id *head,
404 const struct object_id *stash)
405 {
406 struct child_process cmd = CHILD_PROCESS_INIT;
407
408 reset_hard(head);
409
410 if (is_null_oid(stash))
411 goto refresh_cache;
412
413 strvec_pushl(&cmd.args, "stash", "apply", "--index", "--quiet", NULL);
414 strvec_push(&cmd.args, oid_to_hex(stash));
415
416 /*
417 * It is OK to ignore error here, for example when there was
418 * nothing to restore.
419 */
420 cmd.git_cmd = 1;
421 run_command(&cmd);
422
423 refresh_cache:
424 discard_index(the_repository->index);
425 if (repo_read_index(the_repository) < 0)
426 die(_("could not read index"));
427 }
428
429 /* This is called when no merge was necessary. */
430 static void finish_up_to_date(void)
431 {
432 if (verbosity >= 0) {
433 if (squash)
434 puts(_("Already up to date. (nothing to squash)"));
435 else
436 puts(_("Already up to date."));
437 }
438 remove_merge_branch_state(the_repository);
439 }
440
441 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
442 {
443 struct rev_info rev;
444 struct strbuf out = STRBUF_INIT;
445 struct commit_list *j;
446 struct pretty_print_context ctx = {0};
447
448 printf(_("Squash commit -- not updating HEAD\n"));
449
450 repo_init_revisions(the_repository, &rev, NULL);
451 diff_merges_suppress(&rev);
452 rev.commit_format = CMIT_FMT_MEDIUM;
453
454 commit->object.flags |= UNINTERESTING;
455 add_pending_object(&rev, &commit->object, NULL);
456
457 for (j = remoteheads; j; j = j->next)
458 add_pending_object(&rev, &j->item->object, NULL);
459
460 setup_revisions(0, NULL, &rev, NULL);
461 if (prepare_revision_walk(&rev))
462 die(_("revision walk setup failed"));
463
464 ctx.abbrev = rev.abbrev;
465 ctx.date_mode = rev.date_mode;
466 ctx.fmt = rev.commit_format;
467
468 strbuf_addstr(&out, "Squashed commit of the following:\n");
469 while ((commit = get_revision(&rev)) != NULL) {
470 strbuf_addch(&out, '\n');
471 strbuf_addf(&out, "commit %s\n",
472 oid_to_hex(&commit->object.oid));
473 pretty_print_commit(&ctx, commit, &out);
474 }
475 write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
476 strbuf_release(&out);
477 release_revisions(&rev);
478 }
479
480 static void finish(struct commit *head_commit,
481 struct commit_list *remoteheads,
482 const struct object_id *new_head, const char *msg)
483 {
484 struct strbuf reflog_message = STRBUF_INIT;
485 const struct object_id *head = &head_commit->object.oid;
486
487 if (!msg)
488 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
489 else {
490 if (verbosity >= 0)
491 printf("%s\n", msg);
492 strbuf_addf(&reflog_message, "%s: %s",
493 getenv("GIT_REFLOG_ACTION"), msg);
494 }
495 if (squash) {
496 squash_message(head_commit, remoteheads);
497 } else {
498 if (verbosity >= 0 && !merge_msg.len)
499 printf(_("No merge message -- not updating HEAD\n"));
500 else {
501 refs_update_ref(get_main_ref_store(the_repository),
502 reflog_message.buf, "HEAD", new_head,
503 head,
504 0, UPDATE_REFS_DIE_ON_ERR);
505 /*
506 * We ignore errors in 'gc --auto', since the
507 * user should see them.
508 */
509 run_auto_maintenance(the_repository, verbosity < 0);
510 }
511 }
512 if (new_head && show_diffstat) {
513 struct diff_options opts;
514 repo_diff_setup(the_repository, &opts);
515 init_diffstat_widths(&opts);
516
517 switch (show_diffstat) {
518 case MERGE_SHOW_DIFFSTAT: /* 1 */
519 opts.output_format |=
520 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
521 break;
522 case MERGE_SHOW_COMPACTSUMMARY: /* 2 */
523 opts.output_format |= DIFF_FORMAT_DIFFSTAT;
524 opts.flags.stat_with_summary = 1;
525 break;
526 default:
527 break;
528 }
529 opts.detect_rename = DIFF_DETECT_RENAME;
530 diff_setup_done(&opts);
531 diff_tree_oid(head, new_head, "", &opts);
532 diffcore_std(&opts);
533 diff_flush(&opts);
534 }
535
536 /* Run a post-merge hook */
537 run_hooks_l(the_repository, "post-merge", squash ? "1" : "0", NULL);
538
539 if (new_head)
540 apply_autostash_ref(the_repository, "MERGE_AUTOSTASH",
541 NULL, NULL, NULL, NULL);
542 strbuf_release(&reflog_message);
543 }
544
545 /* Get the name for the merge commit's message. */
546 static void merge_name(const char *remote, struct strbuf *msg)
547 {
548 struct commit *remote_head;
549 struct object_id branch_head;
550 struct strbuf bname = STRBUF_INIT;
551 struct merge_remote_desc *desc;
552 const char *ptr;
553 char *found_ref = NULL;
554 int len, early;
555
556 copy_branchname(&bname, remote, 0);
557 remote = bname.buf;
558
559 oidclr(&branch_head, the_repository->hash_algo);
560 remote_head = get_merge_parent(remote);
561 if (!remote_head)
562 die(_("'%s' does not point to a commit"), remote);
563
564 if (repo_dwim_ref(the_repository, remote, strlen(remote), &branch_head,
565 &found_ref, 0) > 0) {
566 if (starts_with(found_ref, "refs/heads/")) {
567 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
568 oid_to_hex(&branch_head), remote);
569 goto cleanup;
570 }
571 if (starts_with(found_ref, "refs/tags/")) {
572 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
573 oid_to_hex(&branch_head), remote);
574 goto cleanup;
575 }
576 if (starts_with(found_ref, "refs/remotes/")) {
577 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
578 oid_to_hex(&branch_head), remote);
579 goto cleanup;
580 }
581 }
582
583 /* See if remote matches <name>^^^.. or <name>~<number> */
584 for (len = 0, ptr = remote + strlen(remote);
585 remote < ptr && ptr[-1] == '^';
586 ptr--)
587 len++;
588 if (len)
589 early = 1;
590 else {
591 early = 0;
592 ptr = strrchr(remote, '~');
593 if (ptr) {
594 int seen_nonzero = 0;
595
596 len++; /* count ~ */
597 while (*++ptr && isdigit(*ptr)) {
598 seen_nonzero |= (*ptr != '0');
599 len++;
600 }
601 if (*ptr)
602 len = 0; /* not ...~<number> */
603 else if (seen_nonzero)
604 early = 1;
605 else if (len == 1)
606 early = 1; /* "name~" is "name~1"! */
607 }
608 }
609 if (len) {
610 struct strbuf truname = STRBUF_INIT;
611 strbuf_addf(&truname, "refs/heads/%s", remote);
612 strbuf_setlen(&truname, truname.len - len);
613 if (refs_ref_exists(get_main_ref_store(the_repository), truname.buf)) {
614 strbuf_addf(msg,
615 "%s\t\tbranch '%s'%s of .\n",
616 oid_to_hex(&remote_head->object.oid),
617 truname.buf + 11,
618 (early ? " (early part)" : ""));
619 strbuf_release(&truname);
620 goto cleanup;
621 }
622 strbuf_release(&truname);
623 }
624
625 desc = merge_remote_util(remote_head);
626 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
627 strbuf_addf(msg, "%s\t\t%s '%s'\n",
628 oid_to_hex(&desc->obj->oid),
629 type_name(desc->obj->type),
630 remote);
631 goto cleanup;
632 }
633
634 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
635 oid_to_hex(&remote_head->object.oid), remote);
636 cleanup:
637 free(found_ref);
638 strbuf_release(&bname);
639 }
640
641 static void parse_branch_merge_options(char *bmo)
642 {
643 const char **argv;
644 int argc;
645
646 if (!bmo)
647 return;
648 argc = split_cmdline(bmo, &argv);
649 if (argc < 0)
650 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
651 _(split_cmdline_strerror(argc)));
652 REALLOC_ARRAY(argv, argc + 2);
653 MOVE_ARRAY(argv + 1, argv, argc + 1);
654 argc++;
655 argv[0] = "branch.*.mergeoptions";
656 parse_options(argc, argv, NULL, builtin_merge_options,
657 builtin_merge_usage, 0);
658 free(argv);
659 }
660
661 static int git_merge_config(const char *k, const char *v,
662 const struct config_context *ctx, void *cb)
663 {
664 int status;
665 const char *str;
666
667 if (branch &&
668 skip_prefix(k, "branch.", &str) &&
669 skip_prefix(str, branch, &str) &&
670 !strcmp(str, ".mergeoptions")) {
671 free(branch_mergeoptions);
672 branch_mergeoptions = xstrdup(v);
673 return 0;
674 }
675
676 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat")) {
677 int val = git_parse_maybe_bool_text(v);
678 switch (val) {
679 case 0:
680 show_diffstat = 0;
681 break;
682 case 1:
683 show_diffstat = MERGE_SHOW_DIFFSTAT;
684 break;
685 default:
686 if (!strcmp(v, "compact"))
687 show_diffstat = MERGE_SHOW_COMPACTSUMMARY;
688 /*
689 * We do not need to have an explicit
690 *
691 * else if (!strcmp(v, "diffstat"))
692 * show_diffstat = MERGE_SHOW_DIFFSTAT;
693 *
694 * here, because the catch-all uses the
695 * diffstat style anyway.
696 */
697 else
698 /*
699 * A setting from a future? It is not an
700 * error grave enough to fail the command.
701 * proceed using the default one.
702 */
703 show_diffstat = MERGE_SHOW_DIFFSTAT;
704 break;
705 }
706 } else if (!strcmp(k, "merge.verifysignatures")) {
707 verify_signatures = git_config_bool(k, v);
708 } else if (!strcmp(k, "pull.twohead")) {
709 FREE_AND_NULL(pull_twohead);
710 return git_config_string(&pull_twohead, k, v);
711 } else if (!strcmp(k, "pull.octopus")) {
712 FREE_AND_NULL(pull_octopus);
713 return git_config_string(&pull_octopus, k, v);
714 } else if (!strcmp(k, "commit.cleanup")) {
715 return git_config_string(&cleanup_arg, k, v);
716 } else if (!strcmp(k, "merge.ff")) {
717 int boolval = git_parse_maybe_bool(v);
718 if (0 <= boolval) {
719 fast_forward = boolval ? FF_ALLOW : FF_NO;
720 } else if (v && !strcmp(v, "only")) {
721 fast_forward = FF_ONLY;
722 } /* do not barf on values from future versions of git */
723 return 0;
724 } else if (!strcmp(k, "merge.defaulttoupstream")) {
725 default_to_upstream = git_config_bool(k, v);
726 return 0;
727 } else if (!strcmp(k, "commit.gpgsign")) {
728 sign_commit = git_config_bool(k, v) ? "" : NULL;
729 return 0;
730 } else if (!strcmp(k, "gpg.mintrustlevel")) {
731 check_trust_level = 0;
732 } else if (!strcmp(k, "merge.autostash")) {
733 autostash = git_config_bool(k, v);
734 return 0;
735 }
736
737 status = fmt_merge_msg_config(k, v, ctx, cb);
738 if (status)
739 return status;
740 return git_diff_ui_config(k, v, ctx, cb);
741 }
742
743 static int read_tree_trivial(struct object_id *common, struct object_id *head,
744 struct object_id *one)
745 {
746 int i, nr_trees = 0;
747 struct tree *trees[MAX_UNPACK_TREES];
748 struct tree_desc t[MAX_UNPACK_TREES];
749 struct unpack_trees_options opts;
750
751 memset(&opts, 0, sizeof(opts));
752 opts.head_idx = 2;
753 opts.src_index = the_repository->index;
754 opts.dst_index = the_repository->index;
755 opts.update = 1;
756 opts.verbose_update = 1;
757 opts.trivial_merges_only = 1;
758 opts.merge = 1;
759 opts.preserve_ignored = 0; /* FIXME: !overwrite_ignore */
760 trees[nr_trees] = repo_parse_tree_indirect(the_repository, common);
761 if (!trees[nr_trees++])
762 return -1;
763 trees[nr_trees] = repo_parse_tree_indirect(the_repository, head);
764 if (!trees[nr_trees++])
765 return -1;
766 trees[nr_trees] = repo_parse_tree_indirect(the_repository, one);
767 if (!trees[nr_trees++])
768 return -1;
769 opts.fn = threeway_merge;
770 cache_tree_free(&the_repository->index->cache_tree);
771 for (i = 0; i < nr_trees; i++) {
772 repo_parse_tree(the_repository, trees[i]);
773 init_tree_desc(t+i, &trees[i]->object.oid,
774 trees[i]->buffer, trees[i]->size);
775 }
776 if (unpack_trees(nr_trees, t, &opts))
777 return -1;
778 return 0;
779 }
780
781 static void write_tree_trivial(struct object_id *oid)
782 {
783 if (write_index_as_tree(oid, the_repository->index,
784 repo_get_index_file(the_repository),
785 0, NULL))
786 die(_("git write-tree failed to write a tree"));
787 }
788
789 static int try_merge_strategy(const char *strategy, struct commit_list *common,
790 struct commit_list *remoteheads,
791 struct commit *head)
792 {
793 const char *head_arg = "HEAD";
794
795 if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET,
796 SKIP_IF_UNCHANGED, 0, NULL, NULL,
797 NULL) < 0)
798 die(_("Unable to write index."));
799
800 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree") ||
801 !strcmp(strategy, "ort")) {
802 struct lock_file lock = LOCK_INIT;
803 int clean, x;
804 struct commit *result;
805 struct commit_list *reversed = NULL;
806 struct merge_options o;
807 struct commit_list *j;
808
809 if (remoteheads->next) {
810 error(_("Not handling anything other than two heads merge."));
811 return 2;
812 }
813
814 init_ui_merge_options(&o, the_repository);
815 if (!strcmp(strategy, "subtree"))
816 o.subtree_shift = "";
817
818 o.show_rename_progress =
819 show_progress == -1 ? isatty(2) : show_progress;
820
821 for (x = 0; x < xopts.nr; x++)
822 if (parse_merge_opt(&o, xopts.v[x]))
823 die(_("unknown strategy option: -X%s"), xopts.v[x]);
824
825 o.branch1 = head_arg;
826 o.branch2 = merge_remote_util(remoteheads->item)->name;
827
828 for (j = common; j; j = j->next)
829 commit_list_insert(j->item, &reversed);
830
831 repo_hold_locked_index(the_repository, &lock,
832 LOCK_DIE_ON_ERROR);
833 clean = merge_ort_recursive(&o, head, remoteheads->item,
834 reversed, &result);
835 commit_list_free(reversed);
836 strbuf_release(&o.obuf);
837
838 if (clean < 0) {
839 rollback_lock_file(&lock);
840 return 2;
841 }
842 if (write_locked_index(the_repository->index, &lock,
843 COMMIT_LOCK | SKIP_IF_UNCHANGED))
844 die(_("unable to write %s"), repo_get_index_file(the_repository));
845 return clean ? 0 : 1;
846 } else {
847 return try_merge_command(the_repository,
848 strategy, xopts.nr, xopts.v,
849 common, head_arg, remoteheads);
850 }
851 }
852
853 static void count_diff_files(struct diff_queue_struct *q,
854 struct diff_options *opt UNUSED, void *data)
855 {
856 int *count = data;
857
858 (*count) += q->nr;
859 }
860
861 static int count_unmerged_entries(void)
862 {
863 int i, ret = 0;
864
865 for (i = 0; i < the_repository->index->cache_nr; i++)
866 if (ce_stage(the_repository->index->cache[i]))
867 ret++;
868
869 return ret;
870 }
871
872 static void add_strategies(const char *string, unsigned attr)
873 {
874 int i;
875
876 if (string) {
877 struct string_list list = STRING_LIST_INIT_DUP;
878 struct string_list_item *item;
879 string_list_split(&list, string, " ", -1);
880 for_each_string_list_item(item, &list)
881 append_strategy(get_strategy(item->string));
882 string_list_clear(&list, 0);
883 return;
884 }
885 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
886 if (all_strategy[i].attr & attr)
887 append_strategy(&all_strategy[i]);
888
889 }
890
891 static void read_merge_msg(struct strbuf *msg)
892 {
893 const char *filename = git_path_merge_msg(the_repository);
894 strbuf_reset(msg);
895 if (strbuf_read_file(msg, filename, 0) < 0)
896 die_errno(_("Could not read from '%s'"), filename);
897 }
898
899 static void write_merge_state(struct commit_list *);
900 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
901 {
902 if (err_msg)
903 error("%s", err_msg);
904 fprintf(stderr,
905 _("Not committing merge; use 'git commit' to complete the merge.\n"));
906 write_merge_state(remoteheads);
907 exit(1);
908 }
909
910 static const char merge_editor_comment[] =
911 N_("Please enter a commit message to explain why this merge is necessary,\n"
912 "especially if it merges an updated upstream into a topic branch.\n"
913 "\n");
914
915 static const char scissors_editor_comment[] =
916 N_("An empty message aborts the commit.\n");
917
918 static const char no_scissors_editor_comment[] =
919 N_("Lines starting with '%s' will be ignored, and an empty message aborts\n"
920 "the commit.\n");
921
922 static void write_merge_heads(struct commit_list *);
923 static void prepare_to_commit(struct commit_list *remoteheads)
924 {
925 struct strbuf msg = STRBUF_INIT;
926 const char *index_file = repo_get_index_file(the_repository);
927
928 if (!no_verify) {
929 int invoked_hook;
930
931 if (run_commit_hook(0 < option_edit, index_file, &invoked_hook,
932 "pre-merge-commit", NULL))
933 abort_commit(remoteheads, NULL);
934 /*
935 * Re-read the index as pre-merge-commit hook could have updated it,
936 * and write it out as a tree. We must do this before we invoke
937 * the editor and after we invoke run_status above.
938 */
939 if (invoked_hook)
940 discard_index(the_repository->index);
941 }
942 read_index_from(the_repository->index, index_file,
943 repo_get_git_dir(the_repository));
944 strbuf_addbuf(&msg, &merge_msg);
945 if (squash)
946 BUG("the control must not reach here under --squash");
947 if (0 < option_edit) {
948 strbuf_addch(&msg, '\n');
949 if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) {
950 wt_status_append_cut_line(&msg);
951 strbuf_commented_addf(&msg, comment_line_str, "\n");
952 }
953 strbuf_commented_addf(&msg, comment_line_str,
954 _(merge_editor_comment));
955 if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS)
956 strbuf_commented_addf(&msg, comment_line_str,
957 _(scissors_editor_comment));
958 else
959 strbuf_commented_addf(&msg, comment_line_str,
960 _(no_scissors_editor_comment), comment_line_str);
961 }
962 if (signoff)
963 append_signoff(&msg, ignored_log_message_bytes(msg.buf, msg.len), 0);
964 write_merge_heads(remoteheads);
965 write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
966 if (run_commit_hook(0 < option_edit, repo_get_index_file(the_repository),
967 NULL, "prepare-commit-msg",
968 git_path_merge_msg(the_repository), "merge", NULL))
969 abort_commit(remoteheads, NULL);
970 if (0 < option_edit) {
971 if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
972 abort_commit(remoteheads, NULL);
973 }
974
975 if (!no_verify && run_commit_hook(0 < option_edit, repo_get_index_file(the_repository),
976 NULL, "commit-msg",
977 git_path_merge_msg(the_repository), NULL))
978 abort_commit(remoteheads, NULL);
979
980 read_merge_msg(&msg);
981 cleanup_message(&msg, cleanup_mode, 0);
982 if (!msg.len)
983 abort_commit(remoteheads, _("Empty commit message."));
984 strbuf_release(&merge_msg);
985 strbuf_addbuf(&merge_msg, &msg);
986 strbuf_release(&msg);
987 }
988
989 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
990 {
991 struct object_id result_tree, result_commit;
992 struct commit_list *parents = NULL, **pptr = &parents;
993
994 if (repo_refresh_and_write_index(the_repository, REFRESH_QUIET,
995 SKIP_IF_UNCHANGED, 0, NULL, NULL,
996 NULL) < 0)
997 return error(_("Unable to write index."));
998
999 write_tree_trivial(&result_tree);
1000 printf(_("Wonderful.\n"));
1001 pptr = commit_list_append(head, pptr);
1002 pptr = commit_list_append(remoteheads->item, pptr);
1003 prepare_to_commit(remoteheads);
1004 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
1005 &result_commit, NULL, sign_commit))
1006 die(_("failed to write commit object"));
1007 finish(head, remoteheads, &result_commit, "In-index merge");
1008
1009 remove_merge_branch_state(the_repository);
1010 commit_list_free(parents);
1011 return 0;
1012 }
1013
1014 static int finish_automerge(struct commit *head,
1015 int head_subsumed,
1016 struct commit_list *common,
1017 struct commit_list *remoteheads,
1018 struct object_id *result_tree,
1019 const char *wt_strategy)
1020 {
1021 struct commit_list *parents = NULL;
1022 struct strbuf buf = STRBUF_INIT;
1023 struct object_id result_commit;
1024
1025 write_tree_trivial(result_tree);
1026 commit_list_free(common);
1027 parents = remoteheads;
1028 if (!head_subsumed || fast_forward == FF_NO)
1029 commit_list_insert(head, &parents);
1030 prepare_to_commit(remoteheads);
1031 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
1032 &result_commit, NULL, sign_commit))
1033 die(_("failed to write commit object"));
1034 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
1035 finish(head, remoteheads, &result_commit, buf.buf);
1036
1037 strbuf_release(&buf);
1038 remove_merge_branch_state(the_repository);
1039 commit_list_free(parents);
1040 return 0;
1041 }
1042
1043 static int suggest_conflicts(void)
1044 {
1045 const char *filename;
1046 FILE *fp;
1047 struct strbuf msgbuf = STRBUF_INIT;
1048
1049 filename = git_path_merge_msg(the_repository);
1050 fp = xfopen(filename, "a");
1051
1052 /*
1053 * We can't use cleanup_mode because if we're not using the editor,
1054 * get_cleanup_mode will return COMMIT_MSG_CLEANUP_SPACE instead, even
1055 * though the message is meant to be processed later by git-commit.
1056 * Thus, we will get the cleanup mode which is returned when we _are_
1057 * using an editor.
1058 */
1059 append_conflicts_hint(the_repository->index, &msgbuf,
1060 get_cleanup_mode(cleanup_arg, 1));
1061 fputs(msgbuf.buf, fp);
1062 strbuf_release(&msgbuf);
1063 fclose(fp);
1064 repo_rerere(the_repository, allow_rerere_auto);
1065 printf(_("Automatic merge failed; "
1066 "fix conflicts and then commit the result.\n"));
1067 return 1;
1068 }
1069
1070 static int evaluate_result(void)
1071 {
1072 int cnt = 0;
1073 struct rev_info rev;
1074
1075 /* Check how many files differ. */
1076 repo_init_revisions(the_repository, &rev, "");
1077 setup_revisions(0, NULL, &rev, NULL);
1078 rev.diffopt.output_format |=
1079 DIFF_FORMAT_CALLBACK;
1080 rev.diffopt.format_callback = count_diff_files;
1081 rev.diffopt.format_callback_data = &cnt;
1082 run_diff_files(&rev, 0);
1083
1084 /*
1085 * Check how many unmerged entries are
1086 * there.
1087 */
1088 cnt += count_unmerged_entries();
1089
1090 release_revisions(&rev);
1091 return cnt;
1092 }
1093
1094 /*
1095 * Pretend as if the user told us to merge with the remote-tracking
1096 * branch we have for the upstream of the current branch
1097 */
1098 static int setup_with_upstream(const char ***argv)
1099 {
1100 struct branch *branch = branch_get(NULL);
1101 int i;
1102 const char **args;
1103
1104 if (!branch)
1105 die(_("No current branch."));
1106 if (!branch->remote_name)
1107 die(_("No remote for the current branch."));
1108 if (!branch->merge_nr)
1109 die(_("No default upstream defined for the current branch."));
1110
1111 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
1112 for (i = 0; i < branch->merge_nr; i++) {
1113 if (!branch->merge[i]->dst)
1114 die(_("No remote-tracking branch for %s from %s"),
1115 branch->merge[i]->src, branch->remote_name);
1116 args[i] = branch->merge[i]->dst;
1117 }
1118 args[i] = NULL;
1119 *argv = args;
1120 return i;
1121 }
1122
1123 static void write_merge_heads(struct commit_list *remoteheads)
1124 {
1125 struct commit_list *j;
1126 struct strbuf buf = STRBUF_INIT;
1127
1128 for (j = remoteheads; j; j = j->next) {
1129 struct object_id *oid;
1130 struct commit *c = j->item;
1131 struct merge_remote_desc *desc;
1132
1133 desc = merge_remote_util(c);
1134 if (desc && desc->obj) {
1135 oid = &desc->obj->oid;
1136 } else {
1137 oid = &c->object.oid;
1138 }
1139 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
1140 }
1141 write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len);
1142
1143 strbuf_reset(&buf);
1144 if (fast_forward == FF_NO)
1145 strbuf_addstr(&buf, "no-ff");
1146 write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len);
1147 strbuf_release(&buf);
1148 }
1149
1150 static void write_merge_state(struct commit_list *remoteheads)
1151 {
1152 write_merge_heads(remoteheads);
1153 strbuf_addch(&merge_msg, '\n');
1154 write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf,
1155 merge_msg.len);
1156 }
1157
1158 static int default_edit_option(void)
1159 {
1160 static const char name[] = "GIT_MERGE_AUTOEDIT";
1161 const char *e = getenv(name);
1162 struct stat st_stdin, st_stdout;
1163
1164 if (have_message)
1165 /* an explicit -m msg without --[no-]edit */
1166 return 0;
1167
1168 if (e) {
1169 int v = git_parse_maybe_bool(e);
1170 if (v < 0)
1171 die(_("Bad value '%s' in environment '%s'"), e, name);
1172 return v;
1173 }
1174
1175 /* Use editor if stdin and stdout are the same and is a tty */
1176 return (!fstat(0, &st_stdin) &&
1177 !fstat(1, &st_stdout) &&
1178 isatty(0) && isatty(1) &&
1179 st_stdin.st_dev == st_stdout.st_dev &&
1180 st_stdin.st_ino == st_stdout.st_ino &&
1181 st_stdin.st_mode == st_stdout.st_mode);
1182 }
1183
1184 static struct commit_list *reduce_parents(struct commit *head_commit,
1185 int *head_subsumed,
1186 struct commit_list *remoteheads)
1187 {
1188 struct commit_list *parents, **remotes;
1189
1190 /*
1191 * Is the current HEAD reachable from another commit being
1192 * merged? If so we do not want to record it as a parent of
1193 * the resulting merge, unless --no-ff is given. We will flip
1194 * this variable to 0 when we find HEAD among the independent
1195 * tips being merged.
1196 */
1197 *head_subsumed = 1;
1198
1199 /* Find what parents to record by checking independent ones. */
1200 parents = reduce_heads(remoteheads);
1201 commit_list_free(remoteheads);
1202
1203 remoteheads = NULL;
1204 remotes = &remoteheads;
1205 while (parents) {
1206 struct commit *commit = pop_commit(&parents);
1207 if (commit == head_commit)
1208 *head_subsumed = 0;
1209 else
1210 remotes = &commit_list_insert(commit, remotes)->next;
1211 }
1212 return remoteheads;
1213 }
1214
1215 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1216 {
1217 struct fmt_merge_msg_opts opts;
1218
1219 memset(&opts, 0, sizeof(opts));
1220 opts.add_title = !have_message;
1221 opts.shortlog_len = shortlog_len;
1222 opts.credit_people = (0 < option_edit);
1223 opts.into_name = into_name;
1224
1225 fmt_merge_msg(merge_names, merge_msg, &opts);
1226 if (merge_msg->len)
1227 strbuf_setlen(merge_msg, merge_msg->len - 1);
1228 }
1229
1230 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1231 {
1232 const char *filename;
1233 int fd, pos, npos;
1234 struct strbuf fetch_head_file = STRBUF_INIT;
1235 const unsigned hexsz = the_hash_algo->hexsz;
1236
1237 if (!merge_names)
1238 merge_names = &fetch_head_file;
1239
1240 filename = git_path_fetch_head(the_repository);
1241 fd = xopen(filename, O_RDONLY);
1242
1243 if (strbuf_read(merge_names, fd, 0) < 0)
1244 die_errno(_("could not read '%s'"), filename);
1245 if (close(fd) < 0)
1246 die_errno(_("could not close '%s'"), filename);
1247
1248 for (pos = 0; pos < merge_names->len; pos = npos) {
1249 struct object_id oid;
1250 char *ptr;
1251 struct commit *commit;
1252
1253 ptr = strchr(merge_names->buf + pos, '\n');
1254 if (ptr)
1255 npos = ptr - merge_names->buf + 1;
1256 else
1257 npos = merge_names->len;
1258
1259 if (npos - pos < hexsz + 2 ||
1260 get_oid_hex(merge_names->buf + pos, &oid))
1261 commit = NULL; /* bad */
1262 else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2))
1263 continue; /* not-for-merge */
1264 else {
1265 char saved = merge_names->buf[pos + hexsz];
1266 merge_names->buf[pos + hexsz] = '\0';
1267 commit = get_merge_parent(merge_names->buf + pos);
1268 merge_names->buf[pos + hexsz] = saved;
1269 }
1270 if (!commit) {
1271 if (ptr)
1272 *ptr = '\0';
1273 die(_("not something we can merge in %s: %s"),
1274 filename, merge_names->buf + pos);
1275 }
1276 remotes = &commit_list_insert(commit, remotes)->next;
1277 }
1278
1279 if (merge_names == &fetch_head_file)
1280 strbuf_release(&fetch_head_file);
1281 }
1282
1283 static struct commit_list *collect_parents(struct commit *head_commit,
1284 int *head_subsumed,
1285 int argc, const char **argv,
1286 struct strbuf *merge_msg)
1287 {
1288 int i;
1289 struct commit_list *remoteheads = NULL;
1290 struct commit_list **remotes = &remoteheads;
1291 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1292
1293 if (merge_msg && (!have_message || shortlog_len))
1294 autogen = &merge_names;
1295
1296 if (head_commit)
1297 remotes = &commit_list_insert(head_commit, remotes)->next;
1298
1299 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1300 handle_fetch_head(remotes, autogen);
1301 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1302 } else {
1303 for (i = 0; i < argc; i++) {
1304 struct commit *commit = get_merge_parent(argv[i]);
1305 if (!commit)
1306 help_unknown_ref(argv[i], "merge",
1307 _("not something we can merge"));
1308 remotes = &commit_list_insert(commit, remotes)->next;
1309 }
1310 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1311 if (autogen) {
1312 struct commit_list *p;
1313 for (p = remoteheads; p; p = p->next)
1314 merge_name(merge_remote_util(p->item)->name, autogen);
1315 }
1316 }
1317
1318 if (autogen) {
1319 prepare_merge_message(autogen, merge_msg);
1320 strbuf_release(autogen);
1321 }
1322
1323 return remoteheads;
1324 }
1325
1326 static int merging_a_throwaway_tag(struct commit *commit)
1327 {
1328 char *tag_ref;
1329 struct object_id oid;
1330 int is_throwaway_tag = 0;
1331
1332 /* Are we merging a tag? */
1333 if (!merge_remote_util(commit) ||
1334 !merge_remote_util(commit)->obj ||
1335 merge_remote_util(commit)->obj->type != OBJ_TAG)
1336 return is_throwaway_tag;
1337
1338 /*
1339 * Now we know we are merging a tag object. Are we downstream
1340 * and following the tags from upstream? If so, we must have
1341 * the tag object pointed at by "refs/tags/$T" where $T is the
1342 * tagname recorded in the tag object. We want to allow such
1343 * a "just to catch up" merge to fast-forward.
1344 *
1345 * Otherwise, we are playing an integrator's role, making a
1346 * merge with a throw-away tag from a contributor with
1347 * something like "git pull $contributor $signed_tag".
1348 * We want to forbid such a merge from fast-forwarding
1349 * by default; otherwise we would not keep the signature
1350 * anywhere.
1351 */
1352 tag_ref = xstrfmt("refs/tags/%s",
1353 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1354 if (!refs_read_ref(get_main_ref_store(the_repository), tag_ref, &oid) &&
1355 oideq(&oid, &merge_remote_util(commit)->obj->oid))
1356 is_throwaway_tag = 0;
1357 else
1358 is_throwaway_tag = 1;
1359 free(tag_ref);
1360 return is_throwaway_tag;
1361 }
1362
1363 int cmd_merge(int argc,
1364 const char **argv,
1365 const char *prefix,
1366 struct repository *repo UNUSED)
1367 {
1368 struct object_id result_tree, stash, head_oid;
1369 struct commit *head_commit;
1370 struct strbuf buf = STRBUF_INIT;
1371 int i, ret = 0, head_subsumed;
1372 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1373 struct commit_list *common = NULL;
1374 const char *best_strategy = NULL, *wt_strategy = NULL;
1375 struct commit_list *remoteheads = NULL, *p;
1376 void *branch_to_free;
1377 int orig_argc = argc;
1378 int merge_log_config = -1;
1379
1380 show_usage_with_options_if_asked(argc, argv,
1381 builtin_merge_usage, builtin_merge_options);
1382
1383 #ifndef WITH_BREAKING_CHANGES
1384 warn_on_auto_comment_char = true;
1385 #endif /* !WITH_BREAKING_CHANGES */
1386 prepare_repo_settings(the_repository);
1387 the_repository->settings.command_requires_full_index = 0;
1388
1389 /*
1390 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1391 * current branch.
1392 */
1393 branch = branch_to_free = refs_resolve_refdup(get_main_ref_store(the_repository),
1394 "HEAD", 0, &head_oid,
1395 NULL);
1396 if (branch)
1397 skip_prefix(branch, "refs/heads/", &branch);
1398
1399 init_diff_ui_defaults();
1400 repo_config(the_repository, git_merge_config, &merge_log_config);
1401
1402 if (!branch || is_null_oid(&head_oid))
1403 head_commit = NULL;
1404 else
1405 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1406
1407 if (branch_mergeoptions)
1408 parse_branch_merge_options(branch_mergeoptions);
1409 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1410 builtin_merge_usage, 0);
1411 if (shortlog_len < 0)
1412 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1413
1414 if (verbosity < 0 && show_progress == -1)
1415 show_progress = 0;
1416
1417 if (abort_current_merge) {
1418 int nargc = 2;
1419 const char *nargv[] = {"reset", "--merge", NULL};
1420 char stash_oid_hex[GIT_MAX_HEXSZ + 1];
1421 struct object_id stash_oid = {0};
1422
1423 if (orig_argc != 2)
1424 usage_msg_opt(_("--abort expects no arguments"),
1425 builtin_merge_usage, builtin_merge_options);
1426
1427 if (!file_exists(git_path_merge_head(the_repository)))
1428 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1429
1430 if (!refs_read_ref(get_main_ref_store(the_repository), "MERGE_AUTOSTASH", &stash_oid))
1431 refs_delete_ref(get_main_ref_store(the_repository),
1432 "", "MERGE_AUTOSTASH", &stash_oid,
1433 REF_NO_DEREF);
1434
1435 /* Invoke 'git reset --merge' */
1436 ret = cmd_reset(nargc, nargv, prefix, the_repository);
1437
1438 if (!is_null_oid(&stash_oid)) {
1439 oid_to_hex_r(stash_oid_hex, &stash_oid);
1440 apply_autostash_oid(stash_oid_hex);
1441 }
1442
1443 goto done;
1444 }
1445
1446 if (quit_current_merge) {
1447 if (orig_argc != 2)
1448 usage_msg_opt(_("--quit expects no arguments"),
1449 builtin_merge_usage,
1450 builtin_merge_options);
1451
1452 remove_merge_branch_state(the_repository);
1453 goto done;
1454 }
1455
1456 if (continue_current_merge) {
1457 int nargc = 1;
1458 const char *nargv[] = {"commit", NULL};
1459
1460 if (orig_argc != 2)
1461 usage_msg_opt(_("--continue expects no arguments"),
1462 builtin_merge_usage, builtin_merge_options);
1463
1464 if (!file_exists(git_path_merge_head(the_repository)))
1465 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1466
1467 /* Invoke 'git commit' */
1468 ret = cmd_commit(nargc, nargv, prefix, the_repository);
1469 goto done;
1470 }
1471
1472 if (repo_read_index_unmerged(the_repository))
1473 die_resolve_conflict("merge");
1474
1475 if (file_exists(git_path_merge_head(the_repository))) {
1476 /*
1477 * There is no unmerged entry, don't advise 'git
1478 * add/rm <file>', just 'git commit'.
1479 */
1480 if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
1481 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1482 "Please, commit your changes before you merge."));
1483 else
1484 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1485 }
1486 if (refs_ref_exists(get_main_ref_store(the_repository), "CHERRY_PICK_HEAD")) {
1487 if (advice_enabled(ADVICE_RESOLVE_CONFLICT))
1488 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1489 "Please, commit your changes before you merge."));
1490 else
1491 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1492 }
1493 resolve_undo_clear_index(the_repository->index);
1494
1495 if (option_edit < 0)
1496 option_edit = default_edit_option();
1497
1498 cleanup_mode = get_cleanup_mode(cleanup_arg, 0 < option_edit);
1499
1500 if (verbosity < 0)
1501 show_diffstat = 0;
1502
1503 if (squash) {
1504 if (fast_forward == FF_NO)
1505 die(_("options '%s' and '%s' cannot be used together"), "--squash", "--no-ff.");
1506 if (option_commit > 0)
1507 die(_("options '%s' and '%s' cannot be used together"), "--squash", "--commit.");
1508 /*
1509 * squash can now silently disable option_commit - this is not
1510 * a problem as it is only overriding the default, not a user
1511 * supplied option.
1512 */
1513 option_commit = 0;
1514 }
1515
1516 if (option_commit < 0)
1517 option_commit = 1;
1518
1519 if (!argc) {
1520 if (default_to_upstream)
1521 argc = setup_with_upstream(&argv);
1522 else
1523 die(_("No commit specified and merge.defaultToUpstream not set."));
1524 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1525 argv[0] = "@{-1}";
1526 }
1527
1528 if (!argc)
1529 usage_with_options(builtin_merge_usage,
1530 builtin_merge_options);
1531
1532 if (!head_commit) {
1533 /*
1534 * If the merged head is a valid one there is no reason
1535 * to forbid "git merge" into a branch yet to be born.
1536 * We do the same for "git pull".
1537 */
1538 struct object_id *remote_head_oid;
1539 if (squash)
1540 die(_("Squash commit into empty head not supported yet"));
1541 if (fast_forward == FF_NO)
1542 die(_("Non-fast-forward commit does not make sense into "
1543 "an empty head"));
1544 remoteheads = collect_parents(head_commit, &head_subsumed,
1545 argc, argv, NULL);
1546 if (!remoteheads)
1547 die(_("%s - not something we can merge"), argv[0]);
1548 if (remoteheads->next)
1549 die(_("Can merge only exactly one commit into empty head"));
1550
1551 if (verify_signatures)
1552 verify_merge_signature(remoteheads->item, verbosity,
1553 check_trust_level);
1554
1555 remote_head_oid = &remoteheads->item->object.oid;
1556 read_empty(remote_head_oid);
1557 refs_update_ref(get_main_ref_store(the_repository),
1558 "initial pull", "HEAD", remote_head_oid, NULL,
1559 0,
1560 UPDATE_REFS_DIE_ON_ERR);
1561 goto done;
1562 }
1563
1564 /*
1565 * All the rest are the commits being merged; prepare
1566 * the standard merge summary message to be appended
1567 * to the given message.
1568 */
1569 remoteheads = collect_parents(head_commit, &head_subsumed,
1570 argc, argv, &merge_msg);
1571
1572 if (!head_commit || !argc)
1573 usage_with_options(builtin_merge_usage,
1574 builtin_merge_options);
1575
1576 if (verify_signatures) {
1577 for (p = remoteheads; p; p = p->next) {
1578 verify_merge_signature(p->item, verbosity,
1579 check_trust_level);
1580 }
1581 }
1582
1583 strbuf_addstr(&buf, "merge");
1584 for (p = remoteheads; p; p = p->next)
1585 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1586 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1587 strbuf_reset(&buf);
1588
1589 for (p = remoteheads; p; p = p->next) {
1590 struct commit *commit = p->item;
1591 strbuf_addf(&buf, "GITHEAD_%s",
1592 oid_to_hex(&commit->object.oid));
1593 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1594 strbuf_reset(&buf);
1595 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1596 fast_forward = FF_NO;
1597 }
1598
1599 if (!use_strategies) {
1600 if (!remoteheads)
1601 ; /* already up-to-date */
1602 else if (!remoteheads->next)
1603 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1604 else
1605 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1606 }
1607
1608 for (i = 0; i < use_strategies_nr; i++) {
1609 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1610 fast_forward = FF_NO;
1611 if (use_strategies[i]->attr & NO_TRIVIAL)
1612 allow_trivial = 0;
1613 }
1614
1615 if (!remoteheads)
1616 ; /* already up-to-date */
1617 else if (!remoteheads->next) {
1618 if (repo_get_merge_bases(the_repository, head_commit,
1619 remoteheads->item, &common) < 0) {
1620 ret = 2;
1621 goto done;
1622 }
1623 } else {
1624 struct commit_list *list = remoteheads;
1625 commit_list_insert(head_commit, &list);
1626 if (get_octopus_merge_bases(list, &common) < 0) {
1627 free(list);
1628 ret = 2;
1629 goto done;
1630 }
1631 free(list);
1632 }
1633
1634 refs_update_ref(get_main_ref_store(the_repository),
1635 "updating ORIG_HEAD", "ORIG_HEAD",
1636 &head_commit->object.oid, NULL, 0,
1637 UPDATE_REFS_DIE_ON_ERR);
1638
1639 if (remoteheads && !common) {
1640 /* No common ancestors found. */
1641 if (!allow_unrelated_histories)
1642 die(_("refusing to merge unrelated histories"));
1643 /* otherwise, we need a real merge. */
1644 } else if (!remoteheads ||
1645 (!remoteheads->next && !common->next &&
1646 common->item == remoteheads->item)) {
1647 /*
1648 * If head can reach all the merge then we are up to date.
1649 * but first the most common case of merging one remote.
1650 */
1651 finish_up_to_date();
1652 goto done;
1653 } else if (fast_forward != FF_NO && !remoteheads->next &&
1654 !common->next &&
1655 oideq(&common->item->object.oid, &head_commit->object.oid)) {
1656 /* Again the most common case of merging one remote. */
1657 const char *msg = have_message ?
1658 "Fast-forward (no commit created; -m option ignored)" :
1659 "Fast-forward";
1660 struct commit *commit;
1661
1662 if (verbosity >= 0) {
1663 printf(_("Updating %s..%s\n"),
1664 repo_find_unique_abbrev(the_repository, &head_commit->object.oid,
1665 DEFAULT_ABBREV),
1666 repo_find_unique_abbrev(the_repository, &remoteheads->item->object.oid,
1667 DEFAULT_ABBREV));
1668 }
1669 commit = remoteheads->item;
1670 if (!commit) {
1671 ret = 1;
1672 goto done;
1673 }
1674
1675 if (autostash)
1676 create_autostash_ref(the_repository, "MERGE_AUTOSTASH",
1677 NULL, false);
1678 if (checkout_fast_forward(the_repository,
1679 &head_commit->object.oid,
1680 &commit->object.oid,
1681 overwrite_ignore)) {
1682 apply_autostash_ref(the_repository, "MERGE_AUTOSTASH",
1683 NULL, NULL, NULL, NULL);
1684 ret = 1;
1685 goto done;
1686 }
1687
1688 finish(head_commit, remoteheads, &commit->object.oid, msg);
1689 remove_merge_branch_state(the_repository);
1690 goto done;
1691 } else if (!remoteheads->next && common->next)
1692 ;
1693 /*
1694 * We are not doing octopus and not fast-forward. Need
1695 * a real merge.
1696 */
1697 else if (!remoteheads->next && !common->next && option_commit) {
1698 /*
1699 * We are not doing octopus, not fast-forward, and have
1700 * only one common.
1701 */
1702 refresh_index(the_repository->index, REFRESH_QUIET, NULL, NULL, NULL);
1703 if (allow_trivial && fast_forward != FF_ONLY) {
1704 /*
1705 * Must first ensure that index matches HEAD before
1706 * attempting a trivial merge.
1707 */
1708 struct tree *head_tree = repo_get_commit_tree(the_repository,
1709 head_commit);
1710 struct strbuf sb = STRBUF_INIT;
1711
1712 if (repo_index_has_changes(the_repository, head_tree,
1713 &sb)) {
1714 error(_("Your local changes to the following files would be overwritten by merge:\n %s"),
1715 sb.buf);
1716 strbuf_release(&sb);
1717 ret = 2;
1718 goto done;
1719 }
1720
1721 /* See if it is really trivial. */
1722 git_committer_info(IDENT_STRICT);
1723 printf(_("Trying really trivial in-index merge...\n"));
1724 if (!read_tree_trivial(&common->item->object.oid,
1725 &head_commit->object.oid,
1726 &remoteheads->item->object.oid)) {
1727 ret = merge_trivial(head_commit, remoteheads);
1728 goto done;
1729 }
1730 printf(_("Nope.\n"));
1731 }
1732 } else {
1733 /*
1734 * An octopus. If we can reach all the remote we are up
1735 * to date.
1736 */
1737 int up_to_date = 1;
1738 struct commit_list *j;
1739
1740 for (j = remoteheads; j; j = j->next) {
1741 int ret = repo_in_merge_bases(the_repository,
1742 j->item, head_commit);
1743 if (ret < 0)
1744 exit(128);
1745 if (!ret) {
1746 up_to_date = 0;
1747 break;
1748 }
1749 }
1750 if (up_to_date) {
1751 finish_up_to_date();
1752 goto done;
1753 }
1754 }
1755
1756 if (fast_forward == FF_ONLY)
1757 die_ff_impossible();
1758
1759 if (autostash)
1760 create_autostash_ref(the_repository, "MERGE_AUTOSTASH",
1761 NULL, false);
1762
1763 /* We are going to make a new commit. */
1764 git_committer_info(IDENT_STRICT);
1765
1766 /*
1767 * At this point, we need a real merge. No matter what strategy
1768 * we use, it would operate on the index, possibly affecting the
1769 * working tree, and when resolved cleanly, have the desired
1770 * tree in the index -- this means that the index must be in
1771 * sync with the head commit. The strategies are responsible
1772 * to ensure this.
1773 *
1774 * Stash away the local changes so that we can try more than one
1775 * and/or recover from merge strategies bailing while leaving the
1776 * index and working tree polluted.
1777 */
1778 if (save_state(&stash))
1779 oidclr(&stash, the_repository->hash_algo);
1780
1781 for (i = 0; i < use_strategies_nr; i++) {
1782 int ret, cnt;
1783 if (i) {
1784 printf(_("Rewinding the tree to pristine...\n"));
1785 restore_state(&head_commit->object.oid, &stash);
1786 }
1787 if (use_strategies_nr != 1)
1788 printf(_("Trying merge strategy %s...\n"),
1789 use_strategies[i]->name);
1790 /*
1791 * Remember which strategy left the state in the working
1792 * tree.
1793 */
1794 wt_strategy = use_strategies[i]->name;
1795
1796 ret = try_merge_strategy(wt_strategy,
1797 common, remoteheads,
1798 head_commit);
1799 /*
1800 * The backend exits with 1 when conflicts are
1801 * left to be resolved, with 2 when it does not
1802 * handle the given merge at all.
1803 */
1804 if (ret < 2) {
1805 if (!ret) {
1806 /*
1807 * This strategy worked; no point in trying
1808 * another.
1809 */
1810 merge_was_ok = 1;
1811 best_strategy = wt_strategy;
1812 break;
1813 }
1814 cnt = (use_strategies_nr > 1) ? evaluate_result() : 0;
1815 if (best_cnt <= 0 || cnt <= best_cnt) {
1816 best_strategy = wt_strategy;
1817 best_cnt = cnt;
1818 }
1819 }
1820 }
1821
1822 /*
1823 * If we have a resulting tree, that means the strategy module
1824 * auto resolved the merge cleanly.
1825 */
1826 if (merge_was_ok && option_commit) {
1827 automerge_was_ok = 1;
1828 ret = finish_automerge(head_commit, head_subsumed,
1829 common, remoteheads,
1830 &result_tree, wt_strategy);
1831 goto done;
1832 }
1833
1834 /*
1835 * Pick the result from the best strategy and have the user fix
1836 * it up.
1837 */
1838 if (!best_strategy) {
1839 restore_state(&head_commit->object.oid, &stash);
1840 if (use_strategies_nr > 1)
1841 fprintf(stderr,
1842 _("No merge strategy handled the merge.\n"));
1843 else
1844 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1845 use_strategies[0]->name);
1846 apply_autostash_ref(the_repository, "MERGE_AUTOSTASH",
1847 NULL, NULL, NULL, NULL);
1848 ret = 2;
1849 goto done;
1850 } else if (best_strategy == wt_strategy)
1851 ; /* We already have its result in the working tree. */
1852 else {
1853 printf(_("Rewinding the tree to pristine...\n"));
1854 restore_state(&head_commit->object.oid, &stash);
1855 printf(_("Using the %s strategy to prepare resolving by hand.\n"),
1856 best_strategy);
1857 try_merge_strategy(best_strategy, common, remoteheads,
1858 head_commit);
1859 }
1860
1861 if (squash) {
1862 finish(head_commit, remoteheads, NULL, NULL);
1863
1864 git_test_write_commit_graph_or_die(the_repository->objects->sources);
1865 } else
1866 write_merge_state(remoteheads);
1867
1868 if (merge_was_ok)
1869 fprintf(stderr, _("Automatic merge went well; "
1870 "stopped before committing as requested\n"));
1871 else
1872 ret = suggest_conflicts();
1873 if (autostash)
1874 printf(_("When finished, apply stashed changes with `git stash pop`\n"));
1875
1876 done:
1877 if (!automerge_was_ok) {
1878 commit_list_free(common);
1879 commit_list_free(remoteheads);
1880 }
1881 strbuf_release(&buf);
1882 free(branch_to_free);
1883 free(pull_twohead);
1884 free(pull_octopus);
1885 discard_index(the_repository->index);
1886 return ret;
1887 }