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#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#define DEFAULT_TWOHEAD (1<<0)
41#define DEFAULT_OCTOPUS (1<<1)
42#define NO_FAST_FORWARD (1<<2)
43#define NO_TRIVIAL (1<<3)
44struct strategy {
46 const char *name;
47 unsigned attr;
48};
49static 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};
56static int show_diffstat = 1, shortlog_len = -1, squash;
58static int option_commit = 1;
59static int option_edit = -1;
60static int allow_trivial = 1, have_message, verify_signatures;
61static int overwrite_ignore = 1;
62static struct strbuf merge_msg = STRBUF_INIT;
63static struct strategy **use_strategies;
64static size_t use_strategies_nr, use_strategies_alloc;
65static const char **xopts;
66static size_t xopts_nr, xopts_alloc;
67static const char *branch;
68static char *branch_mergeoptions;
69static int option_renormalize;
70static int verbosity;
71static int allow_rerere_auto;
72static int abort_current_merge;
73static int continue_current_merge;
74static int allow_unrelated_histories;
75static int show_progress = -1;
76static int default_to_upstream = 1;
77static int signoff;
78static const char *sign_commit;
79static int verify_msg = 1;
80static 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};
88static const char *pull_twohead, *pull_octopus;
90enum ff_type {
92 FF_NO,
93 FF_ALLOW,
94 FF_ONLY
95};
96static enum ff_type fast_forward = FF_ALLOW;
98static int option_parse_message(const struct option *opt,
100 const char *arg, int unset)
101{
102 struct strbuf *buf = opt->value;
103 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}
113static 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 if (unset)
121 BUG("-F cannot be negated");
122 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 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 return 0;
141}
142static 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 if (!name)
151 return NULL;
152 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
154 if (!strcmp(name, all_strategy[i].name))
155 return &all_strategy[i];
156 if (!loaded) {
158 struct cmdnames not_strategies;
159 loaded = 1;
160 memset(¬_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(¬_strategies, ent->name, ent->len);
172 }
173 exclude_cmds(&main_cmds, ¬_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 ret = xcalloc(1, sizeof(struct strategy));
191 ret->name = xstrdup(name);
192 ret->attr = NO_TRIVIAL;
193 return ret;
194}
195static 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}
201static int option_parse_strategy(const struct option *opt,
203 const char *name, int unset)
204{
205 if (unset)
206 return 0;
207 append_strategy(get_strategy(name));
209 return 0;
210}
211static int option_parse_x(const struct option *opt,
213 const char *arg, int unset)
214{
215 if (unset)
216 return 0;
217 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
219 xopts[xopts_nr++] = xstrdup(arg);
220 return 0;
221}
222static int option_parse_n(const struct option *opt,
224 const char *arg, int unset)
225{
226 show_diffstat = unset;
227 return 0;
228}
229static 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/* Cleans up metadata that is uninteresting after a succeeded merge. */
280static void drop_save(void)
281{
282 unlink(git_path_merge_head());
283 unlink(git_path_merge_msg());
284 unlink(git_path_merge_mode());
285}
286static 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 cp.argv = argv;
296 cp.out = -1;
297 cp.git_cmd = 1;
298 if (start_command(&cp))
300 die(_("could not run stash."));
301 len = strbuf_read(&buffer, cp.out, 1024);
302 close(cp.out);
303 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;
312out:
313 strbuf_release(&buffer);
314 return rc;
315}
316static void read_empty(const struct object_id *oid, int verbose)
318{
319 int i = 0;
320 const char *args[7];
321 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 if (run_command_v_opt(args, RUN_GIT_CMD))
332 die(_("read-tree failed"));
333}
334static void reset_hard(const struct object_id *oid, int verbose)
336{
337 int i = 0;
338 const char *args[6];
339 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 if (run_command_v_opt(args, RUN_GIT_CMD))
349 die(_("read-tree failed"));
350}
351static 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 if (is_null_oid(stash))
359 return;
360 reset_hard(head, 1);
362 args[2] = oid_to_hex(stash);
364 /*
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 strbuf_release(&sb);
372 refresh_cache(REFRESH_QUIET);
373}
374/* This is called when no merge was necessary. */
376static 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}
382static 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 printf(_("Squash commit -- not updating HEAD\n"));
391 init_revisions(&rev, NULL);
393 rev.ignore_merges = 1;
394 rev.commit_format = CMIT_FMT_MEDIUM;
395 commit->object.flags |= UNINTERESTING;
397 add_pending_object(&rev, &commit->object, NULL);
398 for (j = remoteheads; j; j = j->next)
400 add_pending_object(&rev, &j->item->object, NULL);
401 setup_revisions(0, NULL, &rev, NULL);
403 if (prepare_revision_walk(&rev))
404 die(_("revision walk setup failed"));
405 ctx.abbrev = rev.abbrev;
407 ctx.date_mode = rev.date_mode;
408 ctx.fmt = rev.commit_format;
409 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(), out.buf, out.len);
418 strbuf_release(&out);
419}
420static 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 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 diff_setup(&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 /* Run a post-merge hook */
468 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
469 strbuf_release(&reflog_message);
471}
472/* Get the name for the merge commit's message. */
474static 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 strbuf_branchname(&bname, remote, 0);
486 remote = bname.buf;
487 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 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 /* 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 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 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 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
563 oid_to_hex(&remote_head->object.oid), remote);
564cleanup:
565 strbuf_release(&buf);
566 strbuf_release(&bname);
567}
568static void parse_branch_merge_options(char *bmo)
570{
571 const char **argv;
572 int argc;
573 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}
588static int git_merge_config(const char *k, const char *v, void *cb)
590{
591 int status;
592 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 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 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}
635static 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 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}
671static 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}
677static 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 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 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 if (remoteheads->next) {
699 error(_("Not handling anything other than two heads merge."));
700 return 2;
701 }
702 init_merge_options(&o);
704 if (!strcmp(strategy, "subtree"))
705 o.subtree_shift = "";
706 o.renormalize = option_renormalize;
708 o.show_rename_progress =
709 show_progress == -1 ? isatty(2) : show_progress;
710 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 o.branch1 = head_arg;
716 o.branch2 = merge_remote_util(remoteheads->item)->name;
717 for (j = common; j; j = j->next)
719 commit_list_insert(j->item, &reversed);
720 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(strategy, xopts_nr, xopts,
732 common, head_arg, remoteheads);
733 }
734}
735static void count_diff_files(struct diff_queue_struct *q,
737 struct diff_options *opt, void *data)
738{
739 int *count = data;
740 (*count) += q->nr;
742}
743static int count_unmerged_entries(void)
745{
746 int i, ret = 0;
747 for (i = 0; i < active_nr; i++)
749 if (ce_stage(active_cache[i]))
750 ret++;
751 return ret;
753}
754static void add_strategies(const char *string, unsigned attr)
756{
757 int i;
758 if (string) {
760 struct string_list list = STRING_LIST_INIT_DUP;
761 struct string_list_item *item;
762 string_list_split(&list, string, ' ', -1);
763 for_each_string_list_item(item, &list)
764 append_strategy(get_strategy(item->string));
765 string_list_clear(&list, 0);
766 return;
767 }
768 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
769 if (all_strategy[i].attr & attr)
770 append_strategy(&all_strategy[i]);
771}
773static void read_merge_msg(struct strbuf *msg)
775{
776 const char *filename = git_path_merge_msg();
777 strbuf_reset(msg);
778 if (strbuf_read_file(msg, filename, 0) < 0)
779 die_errno(_("Could not read from '%s'"), filename);
780}
781static void write_merge_state(struct commit_list *);
783static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
784{
785 if (err_msg)
786 error("%s", err_msg);
787 fprintf(stderr,
788 _("Not committing merge; use 'git commit' to complete the merge.\n"));
789 write_merge_state(remoteheads);
790 exit(1);
791}
792static const char merge_editor_comment[] =
794N_("Please enter a commit message to explain why this merge is necessary,\n"
795 "especially if it merges an updated upstream into a topic branch.\n"
796 "\n"
797 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
798 "the commit.\n");
799static void write_merge_heads(struct commit_list *);
801static void prepare_to_commit(struct commit_list *remoteheads)
802{
803 struct strbuf msg = STRBUF_INIT;
804 strbuf_addbuf(&msg, &merge_msg);
805 strbuf_addch(&msg, '\n');
806 if (squash)
807 BUG("the control must not reach here under --squash");
808 if (0 < option_edit)
809 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
810 if (signoff)
811 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
812 write_merge_heads(remoteheads);
813 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
814 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
815 git_path_merge_msg(), "merge", NULL))
816 abort_commit(remoteheads, NULL);
817 if (0 < option_edit) {
818 if (launch_editor(git_path_merge_msg(), NULL, NULL))
819 abort_commit(remoteheads, NULL);
820 }
821 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
823 "commit-msg",
824 git_path_merge_msg(), NULL))
825 abort_commit(remoteheads, NULL);
826 read_merge_msg(&msg);
828 strbuf_stripspace(&msg, 0 < option_edit);
829 if (!msg.len)
830 abort_commit(remoteheads, _("Empty commit message."));
831 strbuf_release(&merge_msg);
832 strbuf_addbuf(&merge_msg, &msg);
833 strbuf_release(&msg);
834}
835static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
837{
838 struct object_id result_tree, result_commit;
839 struct commit_list *parents, **pptr = &parents;
840 struct lock_file lock = LOCK_INIT;
841 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
843 refresh_cache(REFRESH_QUIET);
844 if (write_locked_index(&the_index, &lock,
845 COMMIT_LOCK | SKIP_IF_UNCHANGED))
846 return error(_("Unable to write index."));
847 write_tree_trivial(&result_tree);
849 printf(_("Wonderful.\n"));
850 pptr = commit_list_append(head, pptr);
851 pptr = commit_list_append(remoteheads->item, pptr);
852 prepare_to_commit(remoteheads);
853 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
854 &result_commit, NULL, sign_commit))
855 die(_("failed to write commit object"));
856 finish(head, remoteheads, &result_commit, "In-index merge");
857 drop_save();
858 return 0;
859}
860static int finish_automerge(struct commit *head,
862 int head_subsumed,
863 struct commit_list *common,
864 struct commit_list *remoteheads,
865 struct object_id *result_tree,
866 const char *wt_strategy)
867{
868 struct commit_list *parents = NULL;
869 struct strbuf buf = STRBUF_INIT;
870 struct object_id result_commit;
871 free_commit_list(common);
873 parents = remoteheads;
874 if (!head_subsumed || fast_forward == FF_NO)
875 commit_list_insert(head, &parents);
876 strbuf_addch(&merge_msg, '\n');
877 prepare_to_commit(remoteheads);
878 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
879 &result_commit, NULL, sign_commit))
880 die(_("failed to write commit object"));
881 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
882 finish(head, remoteheads, &result_commit, buf.buf);
883 strbuf_release(&buf);
884 drop_save();
885 return 0;
886}
887static int suggest_conflicts(void)
889{
890 const char *filename;
891 FILE *fp;
892 struct strbuf msgbuf = STRBUF_INIT;
893 filename = git_path_merge_msg();
895 fp = xfopen(filename, "a");
896 append_conflicts_hint(&msgbuf);
898 fputs(msgbuf.buf, fp);
899 strbuf_release(&msgbuf);
900 fclose(fp);
901 rerere(allow_rerere_auto);
902 printf(_("Automatic merge failed; "
903 "fix conflicts and then commit the result.\n"));
904 return 1;
905}
906static int evaluate_result(void)
908{
909 int cnt = 0;
910 struct rev_info rev;
911 /* Check how many files differ. */
913 init_revisions(&rev, "");
914 setup_revisions(0, NULL, &rev, NULL);
915 rev.diffopt.output_format |=
916 DIFF_FORMAT_CALLBACK;
917 rev.diffopt.format_callback = count_diff_files;
918 rev.diffopt.format_callback_data = &cnt;
919 run_diff_files(&rev, 0);
920 /*
922 * Check how many unmerged entries are
923 * there.
924 */
925 cnt += count_unmerged_entries();
926 return cnt;
928}
929/*
931 * Pretend as if the user told us to merge with the remote-tracking
932 * branch we have for the upstream of the current branch
933 */
934static int setup_with_upstream(const char ***argv)
935{
936 struct branch *branch = branch_get(NULL);
937 int i;
938 const char **args;
939 if (!branch)
941 die(_("No current branch."));
942 if (!branch->remote_name)
943 die(_("No remote for the current branch."));
944 if (!branch->merge_nr)
945 die(_("No default upstream defined for the current branch."));
946 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
948 for (i = 0; i < branch->merge_nr; i++) {
949 if (!branch->merge[i]->dst)
950 die(_("No remote-tracking branch for %s from %s"),
951 branch->merge[i]->src, branch->remote_name);
952 args[i] = branch->merge[i]->dst;
953 }
954 args[i] = NULL;
955 *argv = args;
956 return i;
957}
958static void write_merge_heads(struct commit_list *remoteheads)
960{
961 struct commit_list *j;
962 struct strbuf buf = STRBUF_INIT;
963 for (j = remoteheads; j; j = j->next) {
965 struct object_id *oid;
966 struct commit *c = j->item;
967 struct merge_remote_desc *desc;
968 desc = merge_remote_util(c);
970 if (desc && desc->obj) {
971 oid = &desc->obj->oid;
972 } else {
973 oid = &c->object.oid;
974 }
975 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
976 }
977 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
978 strbuf_reset(&buf);
980 if (fast_forward == FF_NO)
981 strbuf_addstr(&buf, "no-ff");
982 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
983 strbuf_release(&buf);
984}
985static void write_merge_state(struct commit_list *remoteheads)
987{
988 write_merge_heads(remoteheads);
989 strbuf_addch(&merge_msg, '\n');
990 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
991}
992static int default_edit_option(void)
994{
995 static const char name[] = "GIT_MERGE_AUTOEDIT";
996 const char *e = getenv(name);
997 struct stat st_stdin, st_stdout;
998 if (have_message)
1000 /* an explicit -m msg without --[no-]edit */
1001 return 0;
1002 if (e) {
1004 int v = git_parse_maybe_bool(e);
1005 if (v < 0)
1006 die(_("Bad value '%s' in environment '%s'"), e, name);
1007 return v;
1008 }
1009 /* Use editor if stdin and stdout are the same and is a tty */
1011 return (!fstat(0, &st_stdin) &&
1012 !fstat(1, &st_stdout) &&
1013 isatty(0) && isatty(1) &&
1014 st_stdin.st_dev == st_stdout.st_dev &&
1015 st_stdin.st_ino == st_stdout.st_ino &&
1016 st_stdin.st_mode == st_stdout.st_mode);
1017}
1018static struct commit_list *reduce_parents(struct commit *head_commit,
1020 int *head_subsumed,
1021 struct commit_list *remoteheads)
1022{
1023 struct commit_list *parents, **remotes;
1024 /*
1026 * Is the current HEAD reachable from another commit being
1027 * merged? If so we do not want to record it as a parent of
1028 * the resulting merge, unless --no-ff is given. We will flip
1029 * this variable to 0 when we find HEAD among the independent
1030 * tips being merged.
1031 */
1032 *head_subsumed = 1;
1033 /* Find what parents to record by checking independent ones. */
1035 parents = reduce_heads(remoteheads);
1036 free_commit_list(remoteheads);
1037 remoteheads = NULL;
1039 remotes = &remoteheads;
1040 while (parents) {
1041 struct commit *commit = pop_commit(&parents);
1042 if (commit == head_commit)
1043 *head_subsumed = 0;
1044 else
1045 remotes = &commit_list_insert(commit, remotes)->next;
1046 }
1047 return remoteheads;
1048}
1049static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1051{
1052 struct fmt_merge_msg_opts opts;
1053 memset(&opts, 0, sizeof(opts));
1055 opts.add_title = !have_message;
1056 opts.shortlog_len = shortlog_len;
1057 opts.credit_people = (0 < option_edit);
1058 fmt_merge_msg(merge_names, merge_msg, &opts);
1060 if (merge_msg->len)
1061 strbuf_setlen(merge_msg, merge_msg->len - 1);
1062}
1063static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1065{
1066 const char *filename;
1067 int fd, pos, npos;
1068 struct strbuf fetch_head_file = STRBUF_INIT;
1069 if (!merge_names)
1071 merge_names = &fetch_head_file;
1072 filename = git_path_fetch_head();
1074 fd = open(filename, O_RDONLY);
1075 if (fd < 0)
1076 die_errno(_("could not open '%s' for reading"), filename);
1077 if (strbuf_read(merge_names, fd, 0) < 0)
1079 die_errno(_("could not read '%s'"), filename);
1080 if (close(fd) < 0)
1081 die_errno(_("could not close '%s'"), filename);
1082 for (pos = 0; pos < merge_names->len; pos = npos) {
1084 struct object_id oid;
1085 char *ptr;
1086 struct commit *commit;
1087 ptr = strchr(merge_names->buf + pos, '\n');
1089 if (ptr)
1090 npos = ptr - merge_names->buf + 1;
1091 else
1092 npos = merge_names->len;
1093 if (npos - pos < GIT_SHA1_HEXSZ + 2 ||
1095 get_oid_hex(merge_names->buf + pos, &oid))
1096 commit = NULL; /* bad */
1097 else if (memcmp(merge_names->buf + pos + GIT_SHA1_HEXSZ, "\t\t", 2))
1098 continue; /* not-for-merge */
1099 else {
1100 char saved = merge_names->buf[pos + GIT_SHA1_HEXSZ];
1101 merge_names->buf[pos + GIT_SHA1_HEXSZ] = '\0';
1102 commit = get_merge_parent(merge_names->buf + pos);
1103 merge_names->buf[pos + GIT_SHA1_HEXSZ] = saved;
1104 }
1105 if (!commit) {
1106 if (ptr)
1107 *ptr = '\0';
1108 die(_("not something we can merge in %s: %s"),
1109 filename, merge_names->buf + pos);
1110 }
1111 remotes = &commit_list_insert(commit, remotes)->next;
1112 }
1113 if (merge_names == &fetch_head_file)
1115 strbuf_release(&fetch_head_file);
1116}
1117static struct commit_list *collect_parents(struct commit *head_commit,
1119 int *head_subsumed,
1120 int argc, const char **argv,
1121 struct strbuf *merge_msg)
1122{
1123 int i;
1124 struct commit_list *remoteheads = NULL;
1125 struct commit_list **remotes = &remoteheads;
1126 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1127 if (merge_msg && (!have_message || shortlog_len))
1129 autogen = &merge_names;
1130 if (head_commit)
1132 remotes = &commit_list_insert(head_commit, remotes)->next;
1133 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1135 handle_fetch_head(remotes, autogen);
1136 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1137 } else {
1138 for (i = 0; i < argc; i++) {
1139 struct commit *commit = get_merge_parent(argv[i]);
1140 if (!commit)
1141 help_unknown_ref(argv[i], "merge",
1142 _("not something we can merge"));
1143 remotes = &commit_list_insert(commit, remotes)->next;
1144 }
1145 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1146 if (autogen) {
1147 struct commit_list *p;
1148 for (p = remoteheads; p; p = p->next)
1149 merge_name(merge_remote_util(p->item)->name, autogen);
1150 }
1151 }
1152 if (autogen) {
1154 prepare_merge_message(autogen, merge_msg);
1155 strbuf_release(autogen);
1156 }
1157 return remoteheads;
1159}
1160static int merging_a_throwaway_tag(struct commit *commit)
1162{
1163 char *tag_ref;
1164 struct object_id oid;
1165 int is_throwaway_tag = 0;
1166 /* Are we merging a tag? */
1168 if (!merge_remote_util(commit) ||
1169 !merge_remote_util(commit)->obj ||
1170 merge_remote_util(commit)->obj->type != OBJ_TAG)
1171 return is_throwaway_tag;
1172 /*
1174 * Now we know we are merging a tag object. Are we downstream
1175 * and following the tags from upstream? If so, we must have
1176 * the tag object pointed at by "refs/tags/$T" where $T is the
1177 * tagname recorded in the tag object. We want to allow such
1178 * a "just to catch up" merge to fast-forward.
1179 *
1180 * Otherwise, we are playing an integrator's role, making a
1181 * merge with a throw-away tag from a contributor with
1182 * something like "git pull $contributor $signed_tag".
1183 * We want to forbid such a merge from fast-forwarding
1184 * by default; otherwise we would not keep the signature
1185 * anywhere.
1186 */
1187 tag_ref = xstrfmt("refs/tags/%s",
1188 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1189 if (!read_ref(tag_ref, &oid) &&
1190 !oidcmp(&oid, &merge_remote_util(commit)->obj->oid))
1191 is_throwaway_tag = 0;
1192 else
1193 is_throwaway_tag = 1;
1194 free(tag_ref);
1195 return is_throwaway_tag;
1196}
1197int cmd_merge(int argc, const char **argv, const char *prefix)
1199{
1200 struct object_id result_tree, stash, head_oid;
1201 struct commit *head_commit;
1202 struct strbuf buf = STRBUF_INIT;
1203 int i, ret = 0, head_subsumed;
1204 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1205 struct commit_list *common = NULL;
1206 const char *best_strategy = NULL, *wt_strategy = NULL;
1207 struct commit_list *remoteheads, *p;
1208 void *branch_to_free;
1209 int orig_argc = argc;
1210 if (argc == 2 && !strcmp(argv[1], "-h"))
1212 usage_with_options(builtin_merge_usage, builtin_merge_options);
1213 /*
1215 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1216 * current branch.
1217 */
1218 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1219 if (branch)
1220 skip_prefix(branch, "refs/heads/", &branch);
1221 init_diff_ui_defaults();
1223 git_config(git_merge_config, NULL);
1224 if (!branch || is_null_oid(&head_oid))
1226 head_commit = NULL;
1227 else
1228 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1229 if (branch_mergeoptions)
1231 parse_branch_merge_options(branch_mergeoptions);
1232 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1233 builtin_merge_usage, 0);
1234 if (shortlog_len < 0)
1235 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1236 if (verbosity < 0 && show_progress == -1)
1238 show_progress = 0;
1239 if (abort_current_merge) {
1241 int nargc = 2;
1242 const char *nargv[] = {"reset", "--merge", NULL};
1243 if (orig_argc != 2)
1245 usage_msg_opt(_("--abort expects no arguments"),
1246 builtin_merge_usage, builtin_merge_options);
1247 if (!file_exists(git_path_merge_head()))
1249 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1250 /* Invoke 'git reset --merge' */
1252 ret = cmd_reset(nargc, nargv, prefix);
1253 goto done;
1254 }
1255 if (continue_current_merge) {
1257 int nargc = 1;
1258 const char *nargv[] = {"commit", NULL};
1259 if (orig_argc != 2)
1261 usage_msg_opt(_("--continue expects no arguments"),
1262 builtin_merge_usage, builtin_merge_options);
1263 if (!file_exists(git_path_merge_head()))
1265 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1266 /* Invoke 'git commit' */
1268 ret = cmd_commit(nargc, nargv, prefix);
1269 goto done;
1270 }
1271 if (read_cache_unmerged())
1273 die_resolve_conflict("merge");
1274 if (file_exists(git_path_merge_head())) {
1276 /*
1277 * There is no unmerged entry, don't advise 'git
1278 * add/rm <file>', just 'git commit'.
1279 */
1280 if (advice_resolve_conflict)
1281 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1282 "Please, commit your changes before you merge."));
1283 else
1284 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1285 }
1286 if (file_exists(git_path_cherry_pick_head())) {
1287 if (advice_resolve_conflict)
1288 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1289 "Please, commit your changes before you merge."));
1290 else
1291 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1292 }
1293 resolve_undo_clear();
1294 if (verbosity < 0)
1296 show_diffstat = 0;
1297 if (squash) {
1299 if (fast_forward == FF_NO)
1300 die(_("You cannot combine --squash with --no-ff."));
1301 option_commit = 0;
1302 }
1303 if (!argc) {
1305 if (default_to_upstream)
1306 argc = setup_with_upstream(&argv);
1307 else
1308 die(_("No commit specified and merge.defaultToUpstream not set."));
1309 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1310 argv[0] = "@{-1}";
1311 }
1312 if (!argc)
1314 usage_with_options(builtin_merge_usage,
1315 builtin_merge_options);
1316 if (!head_commit) {
1318 /*
1319 * If the merged head is a valid one there is no reason
1320 * to forbid "git merge" into a branch yet to be born.
1321 * We do the same for "git pull".
1322 */
1323 struct object_id *remote_head_oid;
1324 if (squash)
1325 die(_("Squash commit into empty head not supported yet"));
1326 if (fast_forward == FF_NO)
1327 die(_("Non-fast-forward commit does not make sense into "
1328 "an empty head"));
1329 remoteheads = collect_parents(head_commit, &head_subsumed,
1330 argc, argv, NULL);
1331 if (!remoteheads)
1332 die(_("%s - not something we can merge"), argv[0]);
1333 if (remoteheads->next)
1334 die(_("Can merge only exactly one commit into empty head"));
1335 remote_head_oid = &remoteheads->item->object.oid;
1336 read_empty(remote_head_oid, 0);
1337 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1338 UPDATE_REFS_DIE_ON_ERR);
1339 goto done;
1340 }
1341 /*
1343 * All the rest are the commits being merged; prepare
1344 * the standard merge summary message to be appended
1345 * to the given message.
1346 */
1347 remoteheads = collect_parents(head_commit, &head_subsumed,
1348 argc, argv, &merge_msg);
1349 if (!head_commit || !argc)
1351 usage_with_options(builtin_merge_usage,
1352 builtin_merge_options);
1353 if (verify_signatures) {
1355 for (p = remoteheads; p; p = p->next) {
1356 struct commit *commit = p->item;
1357 char hex[GIT_MAX_HEXSZ + 1];
1358 struct signature_check signature_check;
1359 memset(&signature_check, 0, sizeof(signature_check));
1360 check_commit_signature(commit, &signature_check);
1362 find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1364 switch (signature_check.result) {
1365 case 'G':
1366 break;
1367 case 'U':
1368 die(_("Commit %s has an untrusted GPG signature, "
1369 "allegedly by %s."), hex, signature_check.signer);
1370 case 'B':
1371 die(_("Commit %s has a bad GPG signature "
1372 "allegedly by %s."), hex, signature_check.signer);
1373 default: /* 'N' */
1374 die(_("Commit %s does not have a GPG signature."), hex);
1375 }
1376 if (verbosity >= 0 && signature_check.result == 'G')
1377 printf(_("Commit %s has a good GPG signature by %s\n"),
1378 hex, signature_check.signer);
1379 signature_check_clear(&signature_check);
1381 }
1382 }
1383 strbuf_addstr(&buf, "merge");
1385 for (p = remoteheads; p; p = p->next)
1386 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1387 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1388 strbuf_reset(&buf);
1389 for (p = remoteheads; p; p = p->next) {
1391 struct commit *commit = p->item;
1392 strbuf_addf(&buf, "GITHEAD_%s",
1393 oid_to_hex(&commit->object.oid));
1394 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1395 strbuf_reset(&buf);
1396 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1397 fast_forward = FF_NO;
1398 }
1399 if (option_edit < 0)
1401 option_edit = default_edit_option();
1402 if (!use_strategies) {
1404 if (!remoteheads)
1405 ; /* already up-to-date */
1406 else if (!remoteheads->next)
1407 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1408 else
1409 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1410 }
1411 for (i = 0; i < use_strategies_nr; i++) {
1413 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1414 fast_forward = FF_NO;
1415 if (use_strategies[i]->attr & NO_TRIVIAL)
1416 allow_trivial = 0;
1417 }
1418 if (!remoteheads)
1420 ; /* already up-to-date */
1421 else if (!remoteheads->next)
1422 common = get_merge_bases(head_commit, remoteheads->item);
1423 else {
1424 struct commit_list *list = remoteheads;
1425 commit_list_insert(head_commit, &list);
1426 common = get_octopus_merge_bases(list);
1427 free(list);
1428 }
1429 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1431 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1432 if (remoteheads && !common) {
1434 /* No common ancestors found. */
1435 if (!allow_unrelated_histories)
1436 die(_("refusing to merge unrelated histories"));
1437 /* otherwise, we need a real merge. */
1438 } else if (!remoteheads ||
1439 (!remoteheads->next && !common->next &&
1440 common->item == remoteheads->item)) {
1441 /*
1442 * If head can reach all the merge then we are up to date.
1443 * but first the most common case of merging one remote.
1444 */
1445 finish_up_to_date(_("Already up to date."));
1446 goto done;
1447 } else if (fast_forward != FF_NO && !remoteheads->next &&
1448 !common->next &&
1449 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1450 /* Again the most common case of merging one remote. */
1451 struct strbuf msg = STRBUF_INIT;
1452 struct commit *commit;
1453 if (verbosity >= 0) {
1455 printf(_("Updating %s..%s\n"),
1456 find_unique_abbrev(&head_commit->object.oid,
1457 DEFAULT_ABBREV),
1458 find_unique_abbrev(&remoteheads->item->object.oid,
1459 DEFAULT_ABBREV));
1460 }
1461 strbuf_addstr(&msg, "Fast-forward");
1462 if (have_message)
1463 strbuf_addstr(&msg,
1464 " (no commit created; -m option ignored)");
1465 commit = remoteheads->item;
1466 if (!commit) {
1467 ret = 1;
1468 goto done;
1469 }
1470 if (checkout_fast_forward(&head_commit->object.oid,
1472 &commit->object.oid,
1473 overwrite_ignore)) {
1474 ret = 1;
1475 goto done;
1476 }
1477 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1479 drop_save();
1480 goto done;
1481 } else if (!remoteheads->next && common->next)
1482 ;
1483 /*
1484 * We are not doing octopus and not fast-forward. Need
1485 * a real merge.
1486 */
1487 else if (!remoteheads->next && !common->next && option_commit) {
1488 /*
1489 * We are not doing octopus, not fast-forward, and have
1490 * only one common.
1491 */
1492 refresh_cache(REFRESH_QUIET);
1493 if (allow_trivial && fast_forward != FF_ONLY) {
1494 /* See if it is really trivial. */
1495 git_committer_info(IDENT_STRICT);
1496 printf(_("Trying really trivial in-index merge...\n"));
1497 if (!read_tree_trivial(&common->item->object.oid,
1498 &head_commit->object.oid,
1499 &remoteheads->item->object.oid)) {
1500 ret = merge_trivial(head_commit, remoteheads);
1501 goto done;
1502 }
1503 printf(_("Nope.\n"));
1504 }
1505 } else {
1506 /*
1507 * An octopus. If we can reach all the remote we are up
1508 * to date.
1509 */
1510 int up_to_date = 1;
1511 struct commit_list *j;
1512 for (j = remoteheads; j; j = j->next) {
1514 struct commit_list *common_one;
1515 /*
1517 * Here we *have* to calculate the individual
1518 * merge_bases again, otherwise "git merge HEAD^
1519 * HEAD^^" would be missed.
1520 */
1521 common_one = get_merge_bases(head_commit, j->item);
1522 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1523 up_to_date = 0;
1524 break;
1525 }
1526 }
1527 if (up_to_date) {
1528 finish_up_to_date(_("Already up to date. Yeeah!"));
1529 goto done;
1530 }
1531 }
1532 if (fast_forward == FF_ONLY)
1534 die(_("Not possible to fast-forward, aborting."));
1535 /* We are going to make a new commit. */
1537 git_committer_info(IDENT_STRICT);
1538 /*
1540 * At this point, we need a real merge. No matter what strategy
1541 * we use, it would operate on the index, possibly affecting the
1542 * working tree, and when resolved cleanly, have the desired
1543 * tree in the index -- this means that the index must be in
1544 * sync with the head commit. The strategies are responsible
1545 * to ensure this.
1546 */
1547 if (use_strategies_nr == 1 ||
1548 /*
1549 * Stash away the local changes so that we can try more than one.
1550 */
1551 save_state(&stash))
1552 oidclr(&stash);
1553 for (i = 0; i < use_strategies_nr; i++) {
1555 int ret;
1556 if (i) {
1557 printf(_("Rewinding the tree to pristine...\n"));
1558 restore_state(&head_commit->object.oid, &stash);
1559 }
1560 if (use_strategies_nr != 1)
1561 printf(_("Trying merge strategy %s...\n"),
1562 use_strategies[i]->name);
1563 /*
1564 * Remember which strategy left the state in the working
1565 * tree.
1566 */
1567 wt_strategy = use_strategies[i]->name;
1568 ret = try_merge_strategy(use_strategies[i]->name,
1570 common, remoteheads,
1571 head_commit);
1572 if (!option_commit && !ret) {
1573 merge_was_ok = 1;
1574 /*
1575 * This is necessary here just to avoid writing
1576 * the tree, but later we will *not* exit with
1577 * status code 1 because merge_was_ok is set.
1578 */
1579 ret = 1;
1580 }
1581 if (ret) {
1583 /*
1584 * The backend exits with 1 when conflicts are
1585 * left to be resolved, with 2 when it does not
1586 * handle the given merge at all.
1587 */
1588 if (ret == 1) {
1589 int cnt = evaluate_result();
1590 if (best_cnt <= 0 || cnt <= best_cnt) {
1592 best_strategy = use_strategies[i]->name;
1593 best_cnt = cnt;
1594 }
1595 }
1596 if (merge_was_ok)
1597 break;
1598 else
1599 continue;
1600 }
1601 /* Automerge succeeded. */
1603 write_tree_trivial(&result_tree);
1604 automerge_was_ok = 1;
1605 break;
1606 }
1607 /*
1609 * If we have a resulting tree, that means the strategy module
1610 * auto resolved the merge cleanly.
1611 */
1612 if (automerge_was_ok) {
1613 ret = finish_automerge(head_commit, head_subsumed,
1614 common, remoteheads,
1615 &result_tree, wt_strategy);
1616 goto done;
1617 }
1618 /*
1620 * Pick the result from the best strategy and have the user fix
1621 * it up.
1622 */
1623 if (!best_strategy) {
1624 restore_state(&head_commit->object.oid, &stash);
1625 if (use_strategies_nr > 1)
1626 fprintf(stderr,
1627 _("No merge strategy handled the merge.\n"));
1628 else
1629 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1630 use_strategies[0]->name);
1631 ret = 2;
1632 goto done;
1633 } else if (best_strategy == wt_strategy)
1634 ; /* We already have its result in the working tree. */
1635 else {
1636 printf(_("Rewinding the tree to pristine...\n"));
1637 restore_state(&head_commit->object.oid, &stash);
1638 printf(_("Using the %s to prepare resolving by hand.\n"),
1639 best_strategy);
1640 try_merge_strategy(best_strategy, common, remoteheads,
1641 head_commit);
1642 }
1643 if (squash)
1645 finish(head_commit, remoteheads, NULL, NULL);
1646 else
1647 write_merge_state(remoteheads);
1648 if (merge_was_ok)
1650 fprintf(stderr, _("Automatic merge went well; "
1651 "stopped before committing as requested\n"));
1652 else
1653 ret = suggest_conflicts();
1654done:
1656 free(branch_to_free);
1657 return ret;
1658}