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#define USE_THE_INDEX_COMPATIBILITY_MACROS
10#include "cache.h"
11#include "config.h"
12#include "parse-options.h"
13#include "builtin.h"
14#include "lockfile.h"
15#include "run-command.h"
16#include "diff.h"
17#include "refs.h"
18#include "refspec.h"
19#include "commit.h"
20#include "diffcore.h"
21#include "revision.h"
22#include "unpack-trees.h"
23#include "cache-tree.h"
24#include "dir.h"
25#include "utf8.h"
26#include "log-tree.h"
27#include "color.h"
28#include "rerere.h"
29#include "help.h"
30#include "merge-recursive.h"
31#include "resolve-undo.h"
32#include "remote.h"
33#include "fmt-merge-msg.h"
34#include "gpg-interface.h"
35#include "sequencer.h"
36#include "string-list.h"
37#include "packfile.h"
38#include "tag.h"
39#include "alias.h"
40#include "branch.h"
41#include "commit-reach.h"
42#include "wt-status.h"
43#define DEFAULT_TWOHEAD (1<<0)
45#define DEFAULT_OCTOPUS (1<<1)
46#define NO_FAST_FORWARD (1<<2)
47#define NO_TRIVIAL (1<<3)
48struct strategy {
50 const char *name;
51 unsigned attr;
52};
53static const char * const builtin_merge_usage[] = {
55 N_("git merge [<options>] [<commit>...]"),
56 N_("git merge --abort"),
57 N_("git merge --continue"),
58 NULL
59};
60static int show_diffstat = 1, shortlog_len = -1, squash;
62static int option_commit = -1;
63static int option_edit = -1;
64static int allow_trivial = 1, have_message, verify_signatures;
65static int overwrite_ignore = 1;
66static struct strbuf merge_msg = STRBUF_INIT;
67static struct strategy **use_strategies;
68static size_t use_strategies_nr, use_strategies_alloc;
69static const char **xopts;
70static size_t xopts_nr, xopts_alloc;
71static const char *branch;
72static char *branch_mergeoptions;
73static int option_renormalize;
74static int verbosity;
75static int allow_rerere_auto;
76static int abort_current_merge;
77static int quit_current_merge;
78static int continue_current_merge;
79static int allow_unrelated_histories;
80static int show_progress = -1;
81static int default_to_upstream = 1;
82static int signoff;
83static const char *sign_commit;
84static int verify_msg = 1;
85static struct strategy all_strategy[] = {
87 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
88 { "octopus", DEFAULT_OCTOPUS },
89 { "resolve", 0 },
90 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
91 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
92};
93static const char *pull_twohead, *pull_octopus;
95enum ff_type {
97 FF_NO,
98 FF_ALLOW,
99 FF_ONLY
100};
101static enum ff_type fast_forward = FF_ALLOW;
103static const char *cleanup_arg;
105static enum commit_msg_cleanup_mode cleanup_mode;
106static int option_parse_message(const struct option *opt,
108 const char *arg, int unset)
109{
110 struct strbuf *buf = opt->value;
111 if (unset)
113 strbuf_setlen(buf, 0);
114 else if (arg) {
115 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
116 have_message = 1;
117 } else
118 return error(_("switch `m' requires a value"));
119 return 0;
120}
121static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx,
123 const struct option *opt,
124 const char *arg_not_used,
125 int unset)
126{
127 struct strbuf *buf = opt->value;
128 const char *arg;
129 BUG_ON_OPT_ARG(arg_not_used);
131 if (unset)
132 BUG("-F cannot be negated");
133 if (ctx->opt) {
135 arg = ctx->opt;
136 ctx->opt = NULL;
137 } else if (ctx->argc > 1) {
138 ctx->argc--;
139 arg = *++ctx->argv;
140 } else
141 return error(_("option `%s' requires a value"), opt->long_name);
142 if (buf->len)
144 strbuf_addch(buf, '\n');
145 if (ctx->prefix && !is_absolute_path(arg))
146 arg = prefix_filename(ctx->prefix, arg);
147 if (strbuf_read_file(buf, arg, 0) < 0)
148 return error(_("could not read file '%s'"), arg);
149 have_message = 1;
150 return 0;
152}
153static struct strategy *get_strategy(const char *name)
155{
156 int i;
157 struct strategy *ret;
158 static struct cmdnames main_cmds, other_cmds;
159 static int loaded;
160 if (!name)
162 return NULL;
163 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
165 if (!strcmp(name, all_strategy[i].name))
166 return &all_strategy[i];
167 if (!loaded) {
169 struct cmdnames not_strategies;
170 loaded = 1;
171 memset(¬_strategies, 0, sizeof(struct cmdnames));
173 load_command_list("git-merge-", &main_cmds, &other_cmds);
174 for (i = 0; i < main_cmds.cnt; i++) {
175 int j, found = 0;
176 struct cmdname *ent = main_cmds.names[i];
177 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
178 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
179 && !all_strategy[j].name[ent->len])
180 found = 1;
181 if (!found)
182 add_cmdname(¬_strategies, ent->name, ent->len);
183 }
184 exclude_cmds(&main_cmds, ¬_strategies);
185 }
186 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
187 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
188 fprintf(stderr, _("Available strategies are:"));
189 for (i = 0; i < main_cmds.cnt; i++)
190 fprintf(stderr, " %s", main_cmds.names[i]->name);
191 fprintf(stderr, ".\n");
192 if (other_cmds.cnt) {
193 fprintf(stderr, _("Available custom strategies are:"));
194 for (i = 0; i < other_cmds.cnt; i++)
195 fprintf(stderr, " %s", other_cmds.names[i]->name);
196 fprintf(stderr, ".\n");
197 }
198 exit(1);
199 }
200 ret = xcalloc(1, sizeof(struct strategy));
202 ret->name = xstrdup(name);
203 ret->attr = NO_TRIVIAL;
204 return ret;
205}
206static void append_strategy(struct strategy *s)
208{
209 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
210 use_strategies[use_strategies_nr++] = s;
211}
212static int option_parse_strategy(const struct option *opt,
214 const char *name, int unset)
215{
216 if (unset)
217 return 0;
218 append_strategy(get_strategy(name));
220 return 0;
221}
222static int option_parse_x(const struct option *opt,
224 const char *arg, int unset)
225{
226 if (unset)
227 return 0;
228 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
230 xopts[xopts_nr++] = xstrdup(arg);
231 return 0;
232}
233static int option_parse_n(const struct option *opt,
235 const char *arg, int unset)
236{
237 BUG_ON_OPT_ARG(arg);
238 show_diffstat = unset;
239 return 0;
240}
241static struct option builtin_merge_options[] = {
243 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
244 N_("do not show a diffstat at the end of the merge"),
245 PARSE_OPT_NOARG, option_parse_n },
246 OPT_BOOL(0, "stat", &show_diffstat,
247 N_("show a diffstat at the end of the merge")),
248 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
249 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
250 N_("add (at most <n>) entries from shortlog to merge commit message"),
251 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
252 OPT_BOOL(0, "squash", &squash,
253 N_("create a single commit instead of doing a merge")),
254 OPT_BOOL(0, "commit", &option_commit,
255 N_("perform a commit if the merge succeeds (default)")),
256 OPT_BOOL('e', "edit", &option_edit,
257 N_("edit message before committing")),
258 OPT_CLEANUP(&cleanup_arg),
259 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
260 OPT_SET_INT_F(0, "ff-only", &fast_forward,
261 N_("abort if fast-forward is not possible"),
262 FF_ONLY, PARSE_OPT_NONEG),
263 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
264 OPT_BOOL(0, "verify-signatures", &verify_signatures,
265 N_("verify that the named commit has a valid GPG signature")),
266 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
267 N_("merge strategy to use"), option_parse_strategy),
268 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
269 N_("option for selected merge strategy"), option_parse_x),
270 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
271 N_("merge commit message (for a non-fast-forward merge)"),
272 option_parse_message),
273 { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
274 N_("read message from file"), PARSE_OPT_NONEG,
275 NULL, 0, option_read_message },
276 OPT__VERBOSITY(&verbosity),
277 OPT_BOOL(0, "abort", &abort_current_merge,
278 N_("abort the current in-progress merge")),
279 OPT_BOOL(0, "quit", &quit_current_merge,
280 N_("--abort but leave index and working tree alone")),
281 OPT_BOOL(0, "continue", &continue_current_merge,
282 N_("continue the current in-progress merge")),
283 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
284 N_("allow merging unrelated histories")),
285 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
286 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
287 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
288 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
289 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
290 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
291 OPT_END()
292};
293static int save_state(struct object_id *stash)
295{
296 int len;
297 struct child_process cp = CHILD_PROCESS_INIT;
298 struct strbuf buffer = STRBUF_INIT;
299 const char *argv[] = {"stash", "create", NULL};
300 int rc = -1;
301 cp.argv = argv;
303 cp.out = -1;
304 cp.git_cmd = 1;
305 if (start_command(&cp))
307 die(_("could not run stash."));
308 len = strbuf_read(&buffer, cp.out, 1024);
309 close(cp.out);
310 if (finish_command(&cp) || len < 0)
312 die(_("stash failed"));
313 else if (!len) /* no changes */
314 goto out;
315 strbuf_setlen(&buffer, buffer.len-1);
316 if (get_oid(buffer.buf, stash))
317 die(_("not a valid object: %s"), buffer.buf);
318 rc = 0;
319out:
320 strbuf_release(&buffer);
321 return rc;
322}
323static void read_empty(const struct object_id *oid, int verbose)
325{
326 int i = 0;
327 const char *args[7];
328 args[i++] = "read-tree";
330 if (verbose)
331 args[i++] = "-v";
332 args[i++] = "-m";
333 args[i++] = "-u";
334 args[i++] = empty_tree_oid_hex();
335 args[i++] = oid_to_hex(oid);
336 args[i] = NULL;
337 if (run_command_v_opt(args, RUN_GIT_CMD))
339 die(_("read-tree failed"));
340}
341static void reset_hard(const struct object_id *oid, int verbose)
343{
344 int i = 0;
345 const char *args[6];
346 args[i++] = "read-tree";
348 if (verbose)
349 args[i++] = "-v";
350 args[i++] = "--reset";
351 args[i++] = "-u";
352 args[i++] = oid_to_hex(oid);
353 args[i] = NULL;
354 if (run_command_v_opt(args, RUN_GIT_CMD))
356 die(_("read-tree failed"));
357}
358static void restore_state(const struct object_id *head,
360 const struct object_id *stash)
361{
362 struct strbuf sb = STRBUF_INIT;
363 const char *args[] = { "stash", "apply", NULL, NULL };
364 if (is_null_oid(stash))
366 return;
367 reset_hard(head, 1);
369 args[2] = oid_to_hex(stash);
371 /*
373 * It is OK to ignore error here, for example when there was
374 * nothing to restore.
375 */
376 run_command_v_opt(args, RUN_GIT_CMD);
377 strbuf_release(&sb);
379 refresh_cache(REFRESH_QUIET);
380}
381/* This is called when no merge was necessary. */
383static void finish_up_to_date(const char *msg)
384{
385 if (verbosity >= 0)
386 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
387 remove_merge_branch_state(the_repository);
388}
389static void squash_message(struct commit *commit, struct commit_list *remoteheads)
391{
392 struct rev_info rev;
393 struct strbuf out = STRBUF_INIT;
394 struct commit_list *j;
395 struct pretty_print_context ctx = {0};
396 printf(_("Squash commit -- not updating HEAD\n"));
398 repo_init_revisions(the_repository, &rev, NULL);
400 rev.ignore_merges = 1;
401 rev.commit_format = CMIT_FMT_MEDIUM;
402 commit->object.flags |= UNINTERESTING;
404 add_pending_object(&rev, &commit->object, NULL);
405 for (j = remoteheads; j; j = j->next)
407 add_pending_object(&rev, &j->item->object, NULL);
408 setup_revisions(0, NULL, &rev, NULL);
410 if (prepare_revision_walk(&rev))
411 die(_("revision walk setup failed"));
412 ctx.abbrev = rev.abbrev;
414 ctx.date_mode = rev.date_mode;
415 ctx.fmt = rev.commit_format;
416 strbuf_addstr(&out, "Squashed commit of the following:\n");
418 while ((commit = get_revision(&rev)) != NULL) {
419 strbuf_addch(&out, '\n');
420 strbuf_addf(&out, "commit %s\n",
421 oid_to_hex(&commit->object.oid));
422 pretty_print_commit(&ctx, commit, &out);
423 }
424 write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
425 strbuf_release(&out);
426}
427static void finish(struct commit *head_commit,
429 struct commit_list *remoteheads,
430 const struct object_id *new_head, const char *msg)
431{
432 struct strbuf reflog_message = STRBUF_INIT;
433 const struct object_id *head = &head_commit->object.oid;
434 if (!msg)
436 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
437 else {
438 if (verbosity >= 0)
439 printf("%s\n", msg);
440 strbuf_addf(&reflog_message, "%s: %s",
441 getenv("GIT_REFLOG_ACTION"), msg);
442 }
443 if (squash) {
444 squash_message(head_commit, remoteheads);
445 } else {
446 if (verbosity >= 0 && !merge_msg.len)
447 printf(_("No merge message -- not updating HEAD\n"));
448 else {
449 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
450 update_ref(reflog_message.buf, "HEAD", new_head, head,
451 0, UPDATE_REFS_DIE_ON_ERR);
452 /*
453 * We ignore errors in 'gc --auto', since the
454 * user should see them.
455 */
456 close_object_store(the_repository->objects);
457 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
458 }
459 }
460 if (new_head && show_diffstat) {
461 struct diff_options opts;
462 repo_diff_setup(the_repository, &opts);
463 opts.stat_width = -1; /* use full terminal width */
464 opts.stat_graph_width = -1; /* respect statGraphWidth config */
465 opts.output_format |=
466 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
467 opts.detect_rename = DIFF_DETECT_RENAME;
468 diff_setup_done(&opts);
469 diff_tree_oid(head, new_head, "", &opts);
470 diffcore_std(&opts);
471 diff_flush(&opts);
472 }
473 /* Run a post-merge hook */
475 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
476 strbuf_release(&reflog_message);
478}
479/* Get the name for the merge commit's message. */
481static void merge_name(const char *remote, struct strbuf *msg)
482{
483 struct commit *remote_head;
484 struct object_id branch_head;
485 struct strbuf buf = STRBUF_INIT;
486 struct strbuf bname = STRBUF_INIT;
487 struct merge_remote_desc *desc;
488 const char *ptr;
489 char *found_ref;
490 int len, early;
491 strbuf_branchname(&bname, remote, 0);
493 remote = bname.buf;
494 oidclr(&branch_head);
496 remote_head = get_merge_parent(remote);
497 if (!remote_head)
498 die(_("'%s' does not point to a commit"), remote);
499 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
501 if (starts_with(found_ref, "refs/heads/")) {
502 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
503 oid_to_hex(&branch_head), remote);
504 goto cleanup;
505 }
506 if (starts_with(found_ref, "refs/tags/")) {
507 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
508 oid_to_hex(&branch_head), remote);
509 goto cleanup;
510 }
511 if (starts_with(found_ref, "refs/remotes/")) {
512 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
513 oid_to_hex(&branch_head), remote);
514 goto cleanup;
515 }
516 }
517 /* See if remote matches <name>^^^.. or <name>~<number> */
519 for (len = 0, ptr = remote + strlen(remote);
520 remote < ptr && ptr[-1] == '^';
521 ptr--)
522 len++;
523 if (len)
524 early = 1;
525 else {
526 early = 0;
527 ptr = strrchr(remote, '~');
528 if (ptr) {
529 int seen_nonzero = 0;
530 len++; /* count ~ */
532 while (*++ptr && isdigit(*ptr)) {
533 seen_nonzero |= (*ptr != '0');
534 len++;
535 }
536 if (*ptr)
537 len = 0; /* not ...~<number> */
538 else if (seen_nonzero)
539 early = 1;
540 else if (len == 1)
541 early = 1; /* "name~" is "name~1"! */
542 }
543 }
544 if (len) {
545 struct strbuf truname = STRBUF_INIT;
546 strbuf_addf(&truname, "refs/heads/%s", remote);
547 strbuf_setlen(&truname, truname.len - len);
548 if (ref_exists(truname.buf)) {
549 strbuf_addf(msg,
550 "%s\t\tbranch '%s'%s of .\n",
551 oid_to_hex(&remote_head->object.oid),
552 truname.buf + 11,
553 (early ? " (early part)" : ""));
554 strbuf_release(&truname);
555 goto cleanup;
556 }
557 strbuf_release(&truname);
558 }
559 desc = merge_remote_util(remote_head);
561 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
562 strbuf_addf(msg, "%s\t\t%s '%s'\n",
563 oid_to_hex(&desc->obj->oid),
564 type_name(desc->obj->type),
565 remote);
566 goto cleanup;
567 }
568 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
570 oid_to_hex(&remote_head->object.oid), remote);
571cleanup:
572 strbuf_release(&buf);
573 strbuf_release(&bname);
574}
575static void parse_branch_merge_options(char *bmo)
577{
578 const char **argv;
579 int argc;
580 if (!bmo)
582 return;
583 argc = split_cmdline(bmo, &argv);
584 if (argc < 0)
585 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
586 _(split_cmdline_strerror(argc)));
587 REALLOC_ARRAY(argv, argc + 2);
588 MOVE_ARRAY(argv + 1, argv, argc + 1);
589 argc++;
590 argv[0] = "branch.*.mergeoptions";
591 parse_options(argc, argv, NULL, builtin_merge_options,
592 builtin_merge_usage, 0);
593 free(argv);
594}
595static int git_merge_config(const char *k, const char *v, void *cb)
597{
598 int status;
599 if (branch && starts_with(k, "branch.") &&
601 starts_with(k + 7, branch) &&
602 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
603 free(branch_mergeoptions);
604 branch_mergeoptions = xstrdup(v);
605 return 0;
606 }
607 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
609 show_diffstat = git_config_bool(k, v);
610 else if (!strcmp(k, "merge.verifysignatures"))
611 verify_signatures = git_config_bool(k, v);
612 else if (!strcmp(k, "pull.twohead"))
613 return git_config_string(&pull_twohead, k, v);
614 else if (!strcmp(k, "pull.octopus"))
615 return git_config_string(&pull_octopus, k, v);
616 else if (!strcmp(k, "commit.cleanup"))
617 return git_config_string(&cleanup_arg, k, v);
618 else if (!strcmp(k, "merge.renormalize"))
619 option_renormalize = git_config_bool(k, v);
620 else if (!strcmp(k, "merge.ff")) {
621 int boolval = git_parse_maybe_bool(v);
622 if (0 <= boolval) {
623 fast_forward = boolval ? FF_ALLOW : FF_NO;
624 } else if (v && !strcmp(v, "only")) {
625 fast_forward = FF_ONLY;
626 } /* do not barf on values from future versions of git */
627 return 0;
628 } else if (!strcmp(k, "merge.defaulttoupstream")) {
629 default_to_upstream = git_config_bool(k, v);
630 return 0;
631 } else if (!strcmp(k, "commit.gpgsign")) {
632 sign_commit = git_config_bool(k, v) ? "" : NULL;
633 return 0;
634 }
635 status = fmt_merge_msg_config(k, v, cb);
637 if (status)
638 return status;
639 status = git_gpg_config(k, v, NULL);
640 if (status)
641 return status;
642 return git_diff_ui_config(k, v, cb);
643}
644static int read_tree_trivial(struct object_id *common, struct object_id *head,
646 struct object_id *one)
647{
648 int i, nr_trees = 0;
649 struct tree *trees[MAX_UNPACK_TREES];
650 struct tree_desc t[MAX_UNPACK_TREES];
651 struct unpack_trees_options opts;
652 memset(&opts, 0, sizeof(opts));
654 opts.head_idx = 2;
655 opts.src_index = &the_index;
656 opts.dst_index = &the_index;
657 opts.update = 1;
658 opts.verbose_update = 1;
659 opts.trivial_merges_only = 1;
660 opts.merge = 1;
661 trees[nr_trees] = parse_tree_indirect(common);
662 if (!trees[nr_trees++])
663 return -1;
664 trees[nr_trees] = parse_tree_indirect(head);
665 if (!trees[nr_trees++])
666 return -1;
667 trees[nr_trees] = parse_tree_indirect(one);
668 if (!trees[nr_trees++])
669 return -1;
670 opts.fn = threeway_merge;
671 cache_tree_free(&active_cache_tree);
672 for (i = 0; i < nr_trees; i++) {
673 parse_tree(trees[i]);
674 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
675 }
676 if (unpack_trees(nr_trees, t, &opts))
677 return -1;
678 return 0;
679}
680static void write_tree_trivial(struct object_id *oid)
682{
683 if (write_cache_as_tree(oid, 0, NULL))
684 die(_("git write-tree failed to write a tree"));
685}
686static int try_merge_strategy(const char *strategy, struct commit_list *common,
688 struct commit_list *remoteheads,
689 struct commit *head)
690{
691 struct lock_file lock = LOCK_INIT;
692 const char *head_arg = "HEAD";
693 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
695 refresh_cache(REFRESH_QUIET);
696 if (write_locked_index(&the_index, &lock,
697 COMMIT_LOCK | SKIP_IF_UNCHANGED))
698 return error(_("Unable to write index."));
699 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
701 int clean, x;
702 struct commit *result;
703 struct commit_list *reversed = NULL;
704 struct merge_options o;
705 struct commit_list *j;
706 if (remoteheads->next) {
708 error(_("Not handling anything other than two heads merge."));
709 return 2;
710 }
711 init_merge_options(&o, the_repository);
713 if (!strcmp(strategy, "subtree"))
714 o.subtree_shift = "";
715 o.renormalize = option_renormalize;
717 o.show_rename_progress =
718 show_progress == -1 ? isatty(2) : show_progress;
719 for (x = 0; x < xopts_nr; x++)
721 if (parse_merge_opt(&o, xopts[x]))
722 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
723 o.branch1 = head_arg;
725 o.branch2 = merge_remote_util(remoteheads->item)->name;
726 for (j = common; j; j = j->next)
728 commit_list_insert(j->item, &reversed);
729 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
731 clean = merge_recursive(&o, head,
732 remoteheads->item, reversed, &result);
733 if (clean < 0)
734 exit(128);
735 if (write_locked_index(&the_index, &lock,
736 COMMIT_LOCK | SKIP_IF_UNCHANGED))
737 die(_("unable to write %s"), get_index_file());
738 return clean ? 0 : 1;
739 } else {
740 return try_merge_command(the_repository,
741 strategy, xopts_nr, xopts,
742 common, head_arg, remoteheads);
743 }
744}
745static void count_diff_files(struct diff_queue_struct *q,
747 struct diff_options *opt, void *data)
748{
749 int *count = data;
750 (*count) += q->nr;
752}
753static int count_unmerged_entries(void)
755{
756 int i, ret = 0;
757 for (i = 0; i < active_nr; i++)
759 if (ce_stage(active_cache[i]))
760 ret++;
761 return ret;
763}
764static void add_strategies(const char *string, unsigned attr)
766{
767 int i;
768 if (string) {
770 struct string_list list = STRING_LIST_INIT_DUP;
771 struct string_list_item *item;
772 string_list_split(&list, string, ' ', -1);
773 for_each_string_list_item(item, &list)
774 append_strategy(get_strategy(item->string));
775 string_list_clear(&list, 0);
776 return;
777 }
778 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
779 if (all_strategy[i].attr & attr)
780 append_strategy(&all_strategy[i]);
781}
783static void read_merge_msg(struct strbuf *msg)
785{
786 const char *filename = git_path_merge_msg(the_repository);
787 strbuf_reset(msg);
788 if (strbuf_read_file(msg, filename, 0) < 0)
789 die_errno(_("Could not read from '%s'"), filename);
790}
791static void write_merge_state(struct commit_list *);
793static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
794{
795 if (err_msg)
796 error("%s", err_msg);
797 fprintf(stderr,
798 _("Not committing merge; use 'git commit' to complete the merge.\n"));
799 write_merge_state(remoteheads);
800 exit(1);
801}
802static const char merge_editor_comment[] =
804N_("Please enter a commit message to explain why this merge is necessary,\n"
805 "especially if it merges an updated upstream into a topic branch.\n"
806 "\n");
807static const char scissors_editor_comment[] =
809N_("An empty message aborts the commit.\n");
810static const char no_scissors_editor_comment[] =
812N_("Lines starting with '%c' will be ignored, and an empty message aborts\n"
813 "the commit.\n");
814static void write_merge_heads(struct commit_list *);
816static void prepare_to_commit(struct commit_list *remoteheads)
817{
818 struct strbuf msg = STRBUF_INIT;
819 strbuf_addbuf(&msg, &merge_msg);
820 if (squash)
821 BUG("the control must not reach here under --squash");
822 if (0 < option_edit) {
823 strbuf_addch(&msg, '\n');
824 if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) {
825 wt_status_append_cut_line(&msg);
826 strbuf_commented_addf(&msg, "\n");
827 }
828 strbuf_commented_addf(&msg, _(merge_editor_comment));
829 strbuf_commented_addf(&msg, _(cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS ?
830 scissors_editor_comment :
831 no_scissors_editor_comment), comment_line_char);
832 }
833 if (signoff)
834 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
835 write_merge_heads(remoteheads);
836 write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
837 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
838 git_path_merge_msg(the_repository), "merge", NULL))
839 abort_commit(remoteheads, NULL);
840 if (0 < option_edit) {
841 if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
842 abort_commit(remoteheads, NULL);
843 }
844 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
846 "commit-msg",
847 git_path_merge_msg(the_repository), NULL))
848 abort_commit(remoteheads, NULL);
849 read_merge_msg(&msg);
851 cleanup_message(&msg, cleanup_mode, 0);
852 if (!msg.len)
853 abort_commit(remoteheads, _("Empty commit message."));
854 strbuf_release(&merge_msg);
855 strbuf_addbuf(&merge_msg, &msg);
856 strbuf_release(&msg);
857}
858static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
860{
861 struct object_id result_tree, result_commit;
862 struct commit_list *parents, **pptr = &parents;
863 struct lock_file lock = LOCK_INIT;
864 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
866 refresh_cache(REFRESH_QUIET);
867 if (write_locked_index(&the_index, &lock,
868 COMMIT_LOCK | SKIP_IF_UNCHANGED))
869 return error(_("Unable to write index."));
870 write_tree_trivial(&result_tree);
872 printf(_("Wonderful.\n"));
873 pptr = commit_list_append(head, pptr);
874 pptr = commit_list_append(remoteheads->item, pptr);
875 prepare_to_commit(remoteheads);
876 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
877 &result_commit, NULL, sign_commit))
878 die(_("failed to write commit object"));
879 finish(head, remoteheads, &result_commit, "In-index merge");
880 remove_merge_branch_state(the_repository);
881 return 0;
882}
883static int finish_automerge(struct commit *head,
885 int head_subsumed,
886 struct commit_list *common,
887 struct commit_list *remoteheads,
888 struct object_id *result_tree,
889 const char *wt_strategy)
890{
891 struct commit_list *parents = NULL;
892 struct strbuf buf = STRBUF_INIT;
893 struct object_id result_commit;
894 write_tree_trivial(result_tree);
896 free_commit_list(common);
897 parents = remoteheads;
898 if (!head_subsumed || fast_forward == FF_NO)
899 commit_list_insert(head, &parents);
900 prepare_to_commit(remoteheads);
901 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
902 &result_commit, NULL, sign_commit))
903 die(_("failed to write commit object"));
904 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
905 finish(head, remoteheads, &result_commit, buf.buf);
906 strbuf_release(&buf);
907 remove_merge_branch_state(the_repository);
908 return 0;
909}
910static int suggest_conflicts(void)
912{
913 const char *filename;
914 FILE *fp;
915 struct strbuf msgbuf = STRBUF_INIT;
916 filename = git_path_merge_msg(the_repository);
918 fp = xfopen(filename, "a");
919 /*
921 * We can't use cleanup_mode because if we're not using the editor,
922 * get_cleanup_mode will return COMMIT_MSG_CLEANUP_SPACE instead, even
923 * though the message is meant to be processed later by git-commit.
924 * Thus, we will get the cleanup mode which is returned when we _are_
925 * using an editor.
926 */
927 append_conflicts_hint(&the_index, &msgbuf,
928 get_cleanup_mode(cleanup_arg, 1));
929 fputs(msgbuf.buf, fp);
930 strbuf_release(&msgbuf);
931 fclose(fp);
932 repo_rerere(the_repository, allow_rerere_auto);
933 printf(_("Automatic merge failed; "
934 "fix conflicts and then commit the result.\n"));
935 return 1;
936}
937static int evaluate_result(void)
939{
940 int cnt = 0;
941 struct rev_info rev;
942 /* Check how many files differ. */
944 repo_init_revisions(the_repository, &rev, "");
945 setup_revisions(0, NULL, &rev, NULL);
946 rev.diffopt.output_format |=
947 DIFF_FORMAT_CALLBACK;
948 rev.diffopt.format_callback = count_diff_files;
949 rev.diffopt.format_callback_data = &cnt;
950 run_diff_files(&rev, 0);
951 /*
953 * Check how many unmerged entries are
954 * there.
955 */
956 cnt += count_unmerged_entries();
957 return cnt;
959}
960/*
962 * Pretend as if the user told us to merge with the remote-tracking
963 * branch we have for the upstream of the current branch
964 */
965static int setup_with_upstream(const char ***argv)
966{
967 struct branch *branch = branch_get(NULL);
968 int i;
969 const char **args;
970 if (!branch)
972 die(_("No current branch."));
973 if (!branch->remote_name)
974 die(_("No remote for the current branch."));
975 if (!branch->merge_nr)
976 die(_("No default upstream defined for the current branch."));
977 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
979 for (i = 0; i < branch->merge_nr; i++) {
980 if (!branch->merge[i]->dst)
981 die(_("No remote-tracking branch for %s from %s"),
982 branch->merge[i]->src, branch->remote_name);
983 args[i] = branch->merge[i]->dst;
984 }
985 args[i] = NULL;
986 *argv = args;
987 return i;
988}
989static void write_merge_heads(struct commit_list *remoteheads)
991{
992 struct commit_list *j;
993 struct strbuf buf = STRBUF_INIT;
994 for (j = remoteheads; j; j = j->next) {
996 struct object_id *oid;
997 struct commit *c = j->item;
998 struct merge_remote_desc *desc;
999 desc = merge_remote_util(c);
1001 if (desc && desc->obj) {
1002 oid = &desc->obj->oid;
1003 } else {
1004 oid = &c->object.oid;
1005 }
1006 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
1007 }
1008 write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len);
1009 strbuf_reset(&buf);
1011 if (fast_forward == FF_NO)
1012 strbuf_addstr(&buf, "no-ff");
1013 write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len);
1014 strbuf_release(&buf);
1015}
1016static void write_merge_state(struct commit_list *remoteheads)
1018{
1019 write_merge_heads(remoteheads);
1020 strbuf_addch(&merge_msg, '\n');
1021 write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf,
1022 merge_msg.len);
1023}
1024static int default_edit_option(void)
1026{
1027 static const char name[] = "GIT_MERGE_AUTOEDIT";
1028 const char *e = getenv(name);
1029 struct stat st_stdin, st_stdout;
1030 if (have_message)
1032 /* an explicit -m msg without --[no-]edit */
1033 return 0;
1034 if (e) {
1036 int v = git_parse_maybe_bool(e);
1037 if (v < 0)
1038 die(_("Bad value '%s' in environment '%s'"), e, name);
1039 return v;
1040 }
1041 /* Use editor if stdin and stdout are the same and is a tty */
1043 return (!fstat(0, &st_stdin) &&
1044 !fstat(1, &st_stdout) &&
1045 isatty(0) && isatty(1) &&
1046 st_stdin.st_dev == st_stdout.st_dev &&
1047 st_stdin.st_ino == st_stdout.st_ino &&
1048 st_stdin.st_mode == st_stdout.st_mode);
1049}
1050static struct commit_list *reduce_parents(struct commit *head_commit,
1052 int *head_subsumed,
1053 struct commit_list *remoteheads)
1054{
1055 struct commit_list *parents, **remotes;
1056 /*
1058 * Is the current HEAD reachable from another commit being
1059 * merged? If so we do not want to record it as a parent of
1060 * the resulting merge, unless --no-ff is given. We will flip
1061 * this variable to 0 when we find HEAD among the independent
1062 * tips being merged.
1063 */
1064 *head_subsumed = 1;
1065 /* Find what parents to record by checking independent ones. */
1067 parents = reduce_heads(remoteheads);
1068 free_commit_list(remoteheads);
1069 remoteheads = NULL;
1071 remotes = &remoteheads;
1072 while (parents) {
1073 struct commit *commit = pop_commit(&parents);
1074 if (commit == head_commit)
1075 *head_subsumed = 0;
1076 else
1077 remotes = &commit_list_insert(commit, remotes)->next;
1078 }
1079 return remoteheads;
1080}
1081static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1083{
1084 struct fmt_merge_msg_opts opts;
1085 memset(&opts, 0, sizeof(opts));
1087 opts.add_title = !have_message;
1088 opts.shortlog_len = shortlog_len;
1089 opts.credit_people = (0 < option_edit);
1090 fmt_merge_msg(merge_names, merge_msg, &opts);
1092 if (merge_msg->len)
1093 strbuf_setlen(merge_msg, merge_msg->len - 1);
1094}
1095static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1097{
1098 const char *filename;
1099 int fd, pos, npos;
1100 struct strbuf fetch_head_file = STRBUF_INIT;
1101 const unsigned hexsz = the_hash_algo->hexsz;
1102 if (!merge_names)
1104 merge_names = &fetch_head_file;
1105 filename = git_path_fetch_head(the_repository);
1107 fd = open(filename, O_RDONLY);
1108 if (fd < 0)
1109 die_errno(_("could not open '%s' for reading"), filename);
1110 if (strbuf_read(merge_names, fd, 0) < 0)
1112 die_errno(_("could not read '%s'"), filename);
1113 if (close(fd) < 0)
1114 die_errno(_("could not close '%s'"), filename);
1115 for (pos = 0; pos < merge_names->len; pos = npos) {
1117 struct object_id oid;
1118 char *ptr;
1119 struct commit *commit;
1120 ptr = strchr(merge_names->buf + pos, '\n');
1122 if (ptr)
1123 npos = ptr - merge_names->buf + 1;
1124 else
1125 npos = merge_names->len;
1126 if (npos - pos < hexsz + 2 ||
1128 get_oid_hex(merge_names->buf + pos, &oid))
1129 commit = NULL; /* bad */
1130 else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2))
1131 continue; /* not-for-merge */
1132 else {
1133 char saved = merge_names->buf[pos + hexsz];
1134 merge_names->buf[pos + hexsz] = '\0';
1135 commit = get_merge_parent(merge_names->buf + pos);
1136 merge_names->buf[pos + hexsz] = saved;
1137 }
1138 if (!commit) {
1139 if (ptr)
1140 *ptr = '\0';
1141 die(_("not something we can merge in %s: %s"),
1142 filename, merge_names->buf + pos);
1143 }
1144 remotes = &commit_list_insert(commit, remotes)->next;
1145 }
1146 if (merge_names == &fetch_head_file)
1148 strbuf_release(&fetch_head_file);
1149}
1150static struct commit_list *collect_parents(struct commit *head_commit,
1152 int *head_subsumed,
1153 int argc, const char **argv,
1154 struct strbuf *merge_msg)
1155{
1156 int i;
1157 struct commit_list *remoteheads = NULL;
1158 struct commit_list **remotes = &remoteheads;
1159 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1160 if (merge_msg && (!have_message || shortlog_len))
1162 autogen = &merge_names;
1163 if (head_commit)
1165 remotes = &commit_list_insert(head_commit, remotes)->next;
1166 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1168 handle_fetch_head(remotes, autogen);
1169 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1170 } else {
1171 for (i = 0; i < argc; i++) {
1172 struct commit *commit = get_merge_parent(argv[i]);
1173 if (!commit)
1174 help_unknown_ref(argv[i], "merge",
1175 _("not something we can merge"));
1176 remotes = &commit_list_insert(commit, remotes)->next;
1177 }
1178 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1179 if (autogen) {
1180 struct commit_list *p;
1181 for (p = remoteheads; p; p = p->next)
1182 merge_name(merge_remote_util(p->item)->name, autogen);
1183 }
1184 }
1185 if (autogen) {
1187 prepare_merge_message(autogen, merge_msg);
1188 strbuf_release(autogen);
1189 }
1190 return remoteheads;
1192}
1193static int merging_a_throwaway_tag(struct commit *commit)
1195{
1196 char *tag_ref;
1197 struct object_id oid;
1198 int is_throwaway_tag = 0;
1199 /* Are we merging a tag? */
1201 if (!merge_remote_util(commit) ||
1202 !merge_remote_util(commit)->obj ||
1203 merge_remote_util(commit)->obj->type != OBJ_TAG)
1204 return is_throwaway_tag;
1205 /*
1207 * Now we know we are merging a tag object. Are we downstream
1208 * and following the tags from upstream? If so, we must have
1209 * the tag object pointed at by "refs/tags/$T" where $T is the
1210 * tagname recorded in the tag object. We want to allow such
1211 * a "just to catch up" merge to fast-forward.
1212 *
1213 * Otherwise, we are playing an integrator's role, making a
1214 * merge with a throw-away tag from a contributor with
1215 * something like "git pull $contributor $signed_tag".
1216 * We want to forbid such a merge from fast-forwarding
1217 * by default; otherwise we would not keep the signature
1218 * anywhere.
1219 */
1220 tag_ref = xstrfmt("refs/tags/%s",
1221 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1222 if (!read_ref(tag_ref, &oid) &&
1223 oideq(&oid, &merge_remote_util(commit)->obj->oid))
1224 is_throwaway_tag = 0;
1225 else
1226 is_throwaway_tag = 1;
1227 free(tag_ref);
1228 return is_throwaway_tag;
1229}
1230int cmd_merge(int argc, const char **argv, const char *prefix)
1232{
1233 struct object_id result_tree, stash, head_oid;
1234 struct commit *head_commit;
1235 struct strbuf buf = STRBUF_INIT;
1236 int i, ret = 0, head_subsumed;
1237 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1238 struct commit_list *common = NULL;
1239 const char *best_strategy = NULL, *wt_strategy = NULL;
1240 struct commit_list *remoteheads, *p;
1241 void *branch_to_free;
1242 int orig_argc = argc;
1243 if (argc == 2 && !strcmp(argv[1], "-h"))
1245 usage_with_options(builtin_merge_usage, builtin_merge_options);
1246 /*
1248 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1249 * current branch.
1250 */
1251 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1252 if (branch)
1253 skip_prefix(branch, "refs/heads/", &branch);
1254 init_diff_ui_defaults();
1256 git_config(git_merge_config, NULL);
1257 if (!branch || is_null_oid(&head_oid))
1259 head_commit = NULL;
1260 else
1261 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1262 if (branch_mergeoptions)
1264 parse_branch_merge_options(branch_mergeoptions);
1265 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1266 builtin_merge_usage, 0);
1267 if (shortlog_len < 0)
1268 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1269 if (verbosity < 0 && show_progress == -1)
1271 show_progress = 0;
1272 if (abort_current_merge) {
1274 int nargc = 2;
1275 const char *nargv[] = {"reset", "--merge", NULL};
1276 if (orig_argc != 2)
1278 usage_msg_opt(_("--abort expects no arguments"),
1279 builtin_merge_usage, builtin_merge_options);
1280 if (!file_exists(git_path_merge_head(the_repository)))
1282 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1283 /* Invoke 'git reset --merge' */
1285 ret = cmd_reset(nargc, nargv, prefix);
1286 goto done;
1287 }
1288 if (quit_current_merge) {
1290 if (orig_argc != 2)
1291 usage_msg_opt(_("--quit expects no arguments"),
1292 builtin_merge_usage,
1293 builtin_merge_options);
1294 remove_merge_branch_state(the_repository);
1296 goto done;
1297 }
1298 if (continue_current_merge) {
1300 int nargc = 1;
1301 const char *nargv[] = {"commit", NULL};
1302 if (orig_argc != 2)
1304 usage_msg_opt(_("--continue expects no arguments"),
1305 builtin_merge_usage, builtin_merge_options);
1306 if (!file_exists(git_path_merge_head(the_repository)))
1308 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1309 /* Invoke 'git commit' */
1311 ret = cmd_commit(nargc, nargv, prefix);
1312 goto done;
1313 }
1314 if (read_cache_unmerged())
1316 die_resolve_conflict("merge");
1317 if (file_exists(git_path_merge_head(the_repository))) {
1319 /*
1320 * There is no unmerged entry, don't advise 'git
1321 * add/rm <file>', just 'git commit'.
1322 */
1323 if (advice_resolve_conflict)
1324 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1325 "Please, commit your changes before you merge."));
1326 else
1327 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1328 }
1329 if (file_exists(git_path_cherry_pick_head(the_repository))) {
1330 if (advice_resolve_conflict)
1331 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1332 "Please, commit your changes before you merge."));
1333 else
1334 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1335 }
1336 resolve_undo_clear();
1337 if (option_edit < 0)
1339 option_edit = default_edit_option();
1340 cleanup_mode = get_cleanup_mode(cleanup_arg, 0 < option_edit);
1342 if (verbosity < 0)
1344 show_diffstat = 0;
1345 if (squash) {
1347 if (fast_forward == FF_NO)
1348 die(_("You cannot combine --squash with --no-ff."));
1349 if (option_commit > 0)
1350 die(_("You cannot combine --squash with --commit."));
1351 /*
1352 * squash can now silently disable option_commit - this is not
1353 * a problem as it is only overriding the default, not a user
1354 * supplied option.
1355 */
1356 option_commit = 0;
1357 }
1358 if (option_commit < 0)
1360 option_commit = 1;
1361 if (!argc) {
1363 if (default_to_upstream)
1364 argc = setup_with_upstream(&argv);
1365 else
1366 die(_("No commit specified and merge.defaultToUpstream not set."));
1367 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1368 argv[0] = "@{-1}";
1369 }
1370 if (!argc)
1372 usage_with_options(builtin_merge_usage,
1373 builtin_merge_options);
1374 if (!head_commit) {
1376 /*
1377 * If the merged head is a valid one there is no reason
1378 * to forbid "git merge" into a branch yet to be born.
1379 * We do the same for "git pull".
1380 */
1381 struct object_id *remote_head_oid;
1382 if (squash)
1383 die(_("Squash commit into empty head not supported yet"));
1384 if (fast_forward == FF_NO)
1385 die(_("Non-fast-forward commit does not make sense into "
1386 "an empty head"));
1387 remoteheads = collect_parents(head_commit, &head_subsumed,
1388 argc, argv, NULL);
1389 if (!remoteheads)
1390 die(_("%s - not something we can merge"), argv[0]);
1391 if (remoteheads->next)
1392 die(_("Can merge only exactly one commit into empty head"));
1393 if (verify_signatures)
1395 verify_merge_signature(remoteheads->item, verbosity);
1396 remote_head_oid = &remoteheads->item->object.oid;
1398 read_empty(remote_head_oid, 0);
1399 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1400 UPDATE_REFS_DIE_ON_ERR);
1401 goto done;
1402 }
1403 /*
1405 * All the rest are the commits being merged; prepare
1406 * the standard merge summary message to be appended
1407 * to the given message.
1408 */
1409 remoteheads = collect_parents(head_commit, &head_subsumed,
1410 argc, argv, &merge_msg);
1411 if (!head_commit || !argc)
1413 usage_with_options(builtin_merge_usage,
1414 builtin_merge_options);
1415 if (verify_signatures) {
1417 for (p = remoteheads; p; p = p->next) {
1418 verify_merge_signature(p->item, verbosity);
1419 }
1420 }
1421 strbuf_addstr(&buf, "merge");
1423 for (p = remoteheads; p; p = p->next)
1424 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1425 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1426 strbuf_reset(&buf);
1427 for (p = remoteheads; p; p = p->next) {
1429 struct commit *commit = p->item;
1430 strbuf_addf(&buf, "GITHEAD_%s",
1431 oid_to_hex(&commit->object.oid));
1432 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1433 strbuf_reset(&buf);
1434 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1435 fast_forward = FF_NO;
1436 }
1437 if (!use_strategies) {
1439 if (!remoteheads)
1440 ; /* already up-to-date */
1441 else if (!remoteheads->next)
1442 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1443 else
1444 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1445 }
1446 for (i = 0; i < use_strategies_nr; i++) {
1448 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1449 fast_forward = FF_NO;
1450 if (use_strategies[i]->attr & NO_TRIVIAL)
1451 allow_trivial = 0;
1452 }
1453 if (!remoteheads)
1455 ; /* already up-to-date */
1456 else if (!remoteheads->next)
1457 common = get_merge_bases(head_commit, remoteheads->item);
1458 else {
1459 struct commit_list *list = remoteheads;
1460 commit_list_insert(head_commit, &list);
1461 common = get_octopus_merge_bases(list);
1462 free(list);
1463 }
1464 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1466 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1467 if (remoteheads && !common) {
1469 /* No common ancestors found. */
1470 if (!allow_unrelated_histories)
1471 die(_("refusing to merge unrelated histories"));
1472 /* otherwise, we need a real merge. */
1473 } else if (!remoteheads ||
1474 (!remoteheads->next && !common->next &&
1475 common->item == remoteheads->item)) {
1476 /*
1477 * If head can reach all the merge then we are up to date.
1478 * but first the most common case of merging one remote.
1479 */
1480 finish_up_to_date(_("Already up to date."));
1481 goto done;
1482 } else if (fast_forward != FF_NO && !remoteheads->next &&
1483 !common->next &&
1484 oideq(&common->item->object.oid, &head_commit->object.oid)) {
1485 /* Again the most common case of merging one remote. */
1486 struct strbuf msg = STRBUF_INIT;
1487 struct commit *commit;
1488 if (verbosity >= 0) {
1490 printf(_("Updating %s..%s\n"),
1491 find_unique_abbrev(&head_commit->object.oid,
1492 DEFAULT_ABBREV),
1493 find_unique_abbrev(&remoteheads->item->object.oid,
1494 DEFAULT_ABBREV));
1495 }
1496 strbuf_addstr(&msg, "Fast-forward");
1497 if (have_message)
1498 strbuf_addstr(&msg,
1499 " (no commit created; -m option ignored)");
1500 commit = remoteheads->item;
1501 if (!commit) {
1502 ret = 1;
1503 goto done;
1504 }
1505 if (checkout_fast_forward(the_repository,
1507 &head_commit->object.oid,
1508 &commit->object.oid,
1509 overwrite_ignore)) {
1510 ret = 1;
1511 goto done;
1512 }
1513 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1515 remove_merge_branch_state(the_repository);
1516 goto done;
1517 } else if (!remoteheads->next && common->next)
1518 ;
1519 /*
1520 * We are not doing octopus and not fast-forward. Need
1521 * a real merge.
1522 */
1523 else if (!remoteheads->next && !common->next && option_commit) {
1524 /*
1525 * We are not doing octopus, not fast-forward, and have
1526 * only one common.
1527 */
1528 refresh_cache(REFRESH_QUIET);
1529 if (allow_trivial && fast_forward != FF_ONLY) {
1530 /* See if it is really trivial. */
1531 git_committer_info(IDENT_STRICT);
1532 printf(_("Trying really trivial in-index merge...\n"));
1533 if (!read_tree_trivial(&common->item->object.oid,
1534 &head_commit->object.oid,
1535 &remoteheads->item->object.oid)) {
1536 ret = merge_trivial(head_commit, remoteheads);
1537 goto done;
1538 }
1539 printf(_("Nope.\n"));
1540 }
1541 } else {
1542 /*
1543 * An octopus. If we can reach all the remote we are up
1544 * to date.
1545 */
1546 int up_to_date = 1;
1547 struct commit_list *j;
1548 for (j = remoteheads; j; j = j->next) {
1550 struct commit_list *common_one;
1551 /*
1553 * Here we *have* to calculate the individual
1554 * merge_bases again, otherwise "git merge HEAD^
1555 * HEAD^^" would be missed.
1556 */
1557 common_one = get_merge_bases(head_commit, j->item);
1558 if (!oideq(&common_one->item->object.oid, &j->item->object.oid)) {
1559 up_to_date = 0;
1560 break;
1561 }
1562 }
1563 if (up_to_date) {
1564 finish_up_to_date(_("Already up to date. Yeeah!"));
1565 goto done;
1566 }
1567 }
1568 if (fast_forward == FF_ONLY)
1570 die(_("Not possible to fast-forward, aborting."));
1571 /* We are going to make a new commit. */
1573 git_committer_info(IDENT_STRICT);
1574 /*
1576 * At this point, we need a real merge. No matter what strategy
1577 * we use, it would operate on the index, possibly affecting the
1578 * working tree, and when resolved cleanly, have the desired
1579 * tree in the index -- this means that the index must be in
1580 * sync with the head commit. The strategies are responsible
1581 * to ensure this.
1582 */
1583 if (use_strategies_nr == 1 ||
1584 /*
1585 * Stash away the local changes so that we can try more than one.
1586 */
1587 save_state(&stash))
1588 oidclr(&stash);
1589 for (i = 0; !merge_was_ok && i < use_strategies_nr; i++) {
1591 int ret, cnt;
1592 if (i) {
1593 printf(_("Rewinding the tree to pristine...\n"));
1594 restore_state(&head_commit->object.oid, &stash);
1595 }
1596 if (use_strategies_nr != 1)
1597 printf(_("Trying merge strategy %s...\n"),
1598 use_strategies[i]->name);
1599 /*
1600 * Remember which strategy left the state in the working
1601 * tree.
1602 */
1603 wt_strategy = use_strategies[i]->name;
1604 ret = try_merge_strategy(use_strategies[i]->name,
1606 common, remoteheads,
1607 head_commit);
1608 /*
1609 * The backend exits with 1 when conflicts are
1610 * left to be resolved, with 2 when it does not
1611 * handle the given merge at all.
1612 */
1613 if (ret < 2) {
1614 if (!ret) {
1615 if (option_commit) {
1616 /* Automerge succeeded. */
1617 automerge_was_ok = 1;
1618 break;
1619 }
1620 merge_was_ok = 1;
1621 }
1622 cnt = evaluate_result();
1623 if (best_cnt <= 0 || cnt <= best_cnt) {
1624 best_strategy = use_strategies[i]->name;
1625 best_cnt = cnt;
1626 }
1627 }
1628 }
1629 /*
1631 * If we have a resulting tree, that means the strategy module
1632 * auto resolved the merge cleanly.
1633 */
1634 if (automerge_was_ok) {
1635 ret = finish_automerge(head_commit, head_subsumed,
1636 common, remoteheads,
1637 &result_tree, wt_strategy);
1638 goto done;
1639 }
1640 /*
1642 * Pick the result from the best strategy and have the user fix
1643 * it up.
1644 */
1645 if (!best_strategy) {
1646 restore_state(&head_commit->object.oid, &stash);
1647 if (use_strategies_nr > 1)
1648 fprintf(stderr,
1649 _("No merge strategy handled the merge.\n"));
1650 else
1651 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1652 use_strategies[0]->name);
1653 ret = 2;
1654 goto done;
1655 } else if (best_strategy == wt_strategy)
1656 ; /* We already have its result in the working tree. */
1657 else {
1658 printf(_("Rewinding the tree to pristine...\n"));
1659 restore_state(&head_commit->object.oid, &stash);
1660 printf(_("Using the %s to prepare resolving by hand.\n"),
1661 best_strategy);
1662 try_merge_strategy(best_strategy, common, remoteheads,
1663 head_commit);
1664 }
1665 if (squash)
1667 finish(head_commit, remoteheads, NULL, NULL);
1668 else
1669 write_merge_state(remoteheads);
1670 if (merge_was_ok)
1672 fprintf(stderr, _("Automatic merge went well; "
1673 "stopped before committing as requested\n"));
1674 else
1675 ret = suggest_conflicts();
1676done:
1678 free(branch_to_free);
1679 return ret;
1680}