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 "commit-reach.h"
41#define DEFAULT_TWOHEAD (1<<0)
43#define DEFAULT_OCTOPUS (1<<1)
44#define NO_FAST_FORWARD (1<<2)
45#define NO_TRIVIAL (1<<3)
46struct strategy {
48 const char *name;
49 unsigned attr;
50};
51static const char * const builtin_merge_usage[] = {
53 N_("git merge [<options>] [<commit>...]"),
54 N_("git merge --abort"),
55 N_("git merge --continue"),
56 NULL
57};
58static int show_diffstat = 1, shortlog_len = -1, squash;
60static int option_commit = 1;
61static int option_edit = -1;
62static int allow_trivial = 1, have_message, verify_signatures;
63static int overwrite_ignore = 1;
64static struct strbuf merge_msg = STRBUF_INIT;
65static struct strategy **use_strategies;
66static size_t use_strategies_nr, use_strategies_alloc;
67static const char **xopts;
68static size_t xopts_nr, xopts_alloc;
69static const char *branch;
70static char *branch_mergeoptions;
71static int option_renormalize;
72static int verbosity;
73static int allow_rerere_auto;
74static int abort_current_merge;
75static int continue_current_merge;
76static int allow_unrelated_histories;
77static int show_progress = -1;
78static int default_to_upstream = 1;
79static int signoff;
80static const char *sign_commit;
81static int verify_msg = 1;
82static struct strategy all_strategy[] = {
84 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
85 { "octopus", DEFAULT_OCTOPUS },
86 { "resolve", 0 },
87 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
88 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
89};
90static const char *pull_twohead, *pull_octopus;
92enum ff_type {
94 FF_NO,
95 FF_ALLOW,
96 FF_ONLY
97};
98static enum ff_type fast_forward = FF_ALLOW;
100static int option_parse_message(const struct option *opt,
102 const char *arg, int unset)
103{
104 struct strbuf *buf = opt->value;
105 if (unset)
107 strbuf_setlen(buf, 0);
108 else if (arg) {
109 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
110 have_message = 1;
111 } else
112 return error(_("switch `m' requires a value"));
113 return 0;
114}
115static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx,
117 const struct option *opt,
118 const char *arg_not_used,
119 int unset)
120{
121 struct strbuf *buf = opt->value;
122 const char *arg;
123 BUG_ON_OPT_ARG(arg_not_used);
125 if (unset)
126 BUG("-F cannot be negated");
127 if (ctx->opt) {
129 arg = ctx->opt;
130 ctx->opt = NULL;
131 } else if (ctx->argc > 1) {
132 ctx->argc--;
133 arg = *++ctx->argv;
134 } else
135 return error(_("option `%s' requires a value"), opt->long_name);
136 if (buf->len)
138 strbuf_addch(buf, '\n');
139 if (ctx->prefix && !is_absolute_path(arg))
140 arg = prefix_filename(ctx->prefix, arg);
141 if (strbuf_read_file(buf, arg, 0) < 0)
142 return error(_("could not read file '%s'"), arg);
143 have_message = 1;
144 return 0;
146}
147static struct strategy *get_strategy(const char *name)
149{
150 int i;
151 struct strategy *ret;
152 static struct cmdnames main_cmds, other_cmds;
153 static int loaded;
154 if (!name)
156 return NULL;
157 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
159 if (!strcmp(name, all_strategy[i].name))
160 return &all_strategy[i];
161 if (!loaded) {
163 struct cmdnames not_strategies;
164 loaded = 1;
165 memset(¬_strategies, 0, sizeof(struct cmdnames));
167 load_command_list("git-merge-", &main_cmds, &other_cmds);
168 for (i = 0; i < main_cmds.cnt; i++) {
169 int j, found = 0;
170 struct cmdname *ent = main_cmds.names[i];
171 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
172 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
173 && !all_strategy[j].name[ent->len])
174 found = 1;
175 if (!found)
176 add_cmdname(¬_strategies, ent->name, ent->len);
177 }
178 exclude_cmds(&main_cmds, ¬_strategies);
179 }
180 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
181 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
182 fprintf(stderr, _("Available strategies are:"));
183 for (i = 0; i < main_cmds.cnt; i++)
184 fprintf(stderr, " %s", main_cmds.names[i]->name);
185 fprintf(stderr, ".\n");
186 if (other_cmds.cnt) {
187 fprintf(stderr, _("Available custom strategies are:"));
188 for (i = 0; i < other_cmds.cnt; i++)
189 fprintf(stderr, " %s", other_cmds.names[i]->name);
190 fprintf(stderr, ".\n");
191 }
192 exit(1);
193 }
194 ret = xcalloc(1, sizeof(struct strategy));
196 ret->name = xstrdup(name);
197 ret->attr = NO_TRIVIAL;
198 return ret;
199}
200static void append_strategy(struct strategy *s)
202{
203 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
204 use_strategies[use_strategies_nr++] = s;
205}
206static int option_parse_strategy(const struct option *opt,
208 const char *name, int unset)
209{
210 if (unset)
211 return 0;
212 append_strategy(get_strategy(name));
214 return 0;
215}
216static int option_parse_x(const struct option *opt,
218 const char *arg, int unset)
219{
220 if (unset)
221 return 0;
222 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
224 xopts[xopts_nr++] = xstrdup(arg);
225 return 0;
226}
227static int option_parse_n(const struct option *opt,
229 const char *arg, int unset)
230{
231 BUG_ON_OPT_ARG(arg);
232 show_diffstat = unset;
233 return 0;
234}
235static struct option builtin_merge_options[] = {
237 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
238 N_("do not show a diffstat at the end of the merge"),
239 PARSE_OPT_NOARG, option_parse_n },
240 OPT_BOOL(0, "stat", &show_diffstat,
241 N_("show a diffstat at the end of the merge")),
242 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
243 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
244 N_("add (at most <n>) entries from shortlog to merge commit message"),
245 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
246 OPT_BOOL(0, "squash", &squash,
247 N_("create a single commit instead of doing a merge")),
248 OPT_BOOL(0, "commit", &option_commit,
249 N_("perform a commit if the merge succeeds (default)")),
250 OPT_BOOL('e', "edit", &option_edit,
251 N_("edit message before committing")),
252 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
253 OPT_SET_INT_F(0, "ff-only", &fast_forward,
254 N_("abort if fast-forward is not possible"),
255 FF_ONLY, PARSE_OPT_NONEG),
256 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
257 OPT_BOOL(0, "verify-signatures", &verify_signatures,
258 N_("verify that the named commit has a valid GPG signature")),
259 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
260 N_("merge strategy to use"), option_parse_strategy),
261 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
262 N_("option for selected merge strategy"), option_parse_x),
263 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
264 N_("merge commit message (for a non-fast-forward merge)"),
265 option_parse_message),
266 { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
267 N_("read message from file"), PARSE_OPT_NONEG,
268 NULL, 0, option_read_message },
269 OPT__VERBOSITY(&verbosity),
270 OPT_BOOL(0, "abort", &abort_current_merge,
271 N_("abort the current in-progress merge")),
272 OPT_BOOL(0, "continue", &continue_current_merge,
273 N_("continue the current in-progress merge")),
274 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
275 N_("allow merging unrelated histories")),
276 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
277 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
278 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
279 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
280 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
281 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
282 OPT_END()
283};
284/* Cleans up metadata that is uninteresting after a succeeded merge. */
286static void drop_save(void)
287{
288 unlink(git_path_merge_head(the_repository));
289 unlink(git_path_merge_msg(the_repository));
290 unlink(git_path_merge_mode(the_repository));
291}
292static int save_state(struct object_id *stash)
294{
295 int len;
296 struct child_process cp = CHILD_PROCESS_INIT;
297 struct strbuf buffer = STRBUF_INIT;
298 const char *argv[] = {"stash", "create", NULL};
299 int rc = -1;
300 cp.argv = argv;
302 cp.out = -1;
303 cp.git_cmd = 1;
304 if (start_command(&cp))
306 die(_("could not run stash."));
307 len = strbuf_read(&buffer, cp.out, 1024);
308 close(cp.out);
309 if (finish_command(&cp) || len < 0)
311 die(_("stash failed"));
312 else if (!len) /* no changes */
313 goto out;
314 strbuf_setlen(&buffer, buffer.len-1);
315 if (get_oid(buffer.buf, stash))
316 die(_("not a valid object: %s"), buffer.buf);
317 rc = 0;
318out:
319 strbuf_release(&buffer);
320 return rc;
321}
322static void read_empty(const struct object_id *oid, int verbose)
324{
325 int i = 0;
326 const char *args[7];
327 args[i++] = "read-tree";
329 if (verbose)
330 args[i++] = "-v";
331 args[i++] = "-m";
332 args[i++] = "-u";
333 args[i++] = empty_tree_oid_hex();
334 args[i++] = oid_to_hex(oid);
335 args[i] = NULL;
336 if (run_command_v_opt(args, RUN_GIT_CMD))
338 die(_("read-tree failed"));
339}
340static void reset_hard(const struct object_id *oid, int verbose)
342{
343 int i = 0;
344 const char *args[6];
345 args[i++] = "read-tree";
347 if (verbose)
348 args[i++] = "-v";
349 args[i++] = "--reset";
350 args[i++] = "-u";
351 args[i++] = oid_to_hex(oid);
352 args[i] = NULL;
353 if (run_command_v_opt(args, RUN_GIT_CMD))
355 die(_("read-tree failed"));
356}
357static void restore_state(const struct object_id *head,
359 const struct object_id *stash)
360{
361 struct strbuf sb = STRBUF_INIT;
362 const char *args[] = { "stash", "apply", NULL, NULL };
363 if (is_null_oid(stash))
365 return;
366 reset_hard(head, 1);
368 args[2] = oid_to_hex(stash);
370 /*
372 * It is OK to ignore error here, for example when there was
373 * nothing to restore.
374 */
375 run_command_v_opt(args, RUN_GIT_CMD);
376 strbuf_release(&sb);
378 refresh_cache(REFRESH_QUIET);
379}
380/* This is called when no merge was necessary. */
382static void finish_up_to_date(const char *msg)
383{
384 if (verbosity >= 0)
385 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
386 drop_save();
387}
388static void squash_message(struct commit *commit, struct commit_list *remoteheads)
390{
391 struct rev_info rev;
392 struct strbuf out = STRBUF_INIT;
393 struct commit_list *j;
394 struct pretty_print_context ctx = {0};
395 printf(_("Squash commit -- not updating HEAD\n"));
397 repo_init_revisions(the_repository, &rev, NULL);
399 rev.ignore_merges = 1;
400 rev.commit_format = CMIT_FMT_MEDIUM;
401 commit->object.flags |= UNINTERESTING;
403 add_pending_object(&rev, &commit->object, NULL);
404 for (j = remoteheads; j; j = j->next)
406 add_pending_object(&rev, &j->item->object, NULL);
407 setup_revisions(0, NULL, &rev, NULL);
409 if (prepare_revision_walk(&rev))
410 die(_("revision walk setup failed"));
411 ctx.abbrev = rev.abbrev;
413 ctx.date_mode = rev.date_mode;
414 ctx.fmt = rev.commit_format;
415 strbuf_addstr(&out, "Squashed commit of the following:\n");
417 while ((commit = get_revision(&rev)) != NULL) {
418 strbuf_addch(&out, '\n');
419 strbuf_addf(&out, "commit %s\n",
420 oid_to_hex(&commit->object.oid));
421 pretty_print_commit(&ctx, commit, &out);
422 }
423 write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
424 strbuf_release(&out);
425}
426static void finish(struct commit *head_commit,
428 struct commit_list *remoteheads,
429 const struct object_id *new_head, const char *msg)
430{
431 struct strbuf reflog_message = STRBUF_INIT;
432 const struct object_id *head = &head_commit->object.oid;
433 if (!msg)
435 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
436 else {
437 if (verbosity >= 0)
438 printf("%s\n", msg);
439 strbuf_addf(&reflog_message, "%s: %s",
440 getenv("GIT_REFLOG_ACTION"), msg);
441 }
442 if (squash) {
443 squash_message(head_commit, remoteheads);
444 } else {
445 if (verbosity >= 0 && !merge_msg.len)
446 printf(_("No merge message -- not updating HEAD\n"));
447 else {
448 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
449 update_ref(reflog_message.buf, "HEAD", new_head, head,
450 0, UPDATE_REFS_DIE_ON_ERR);
451 /*
452 * We ignore errors in 'gc --auto', since the
453 * user should see them.
454 */
455 close_all_packs(the_repository->objects);
456 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
457 }
458 }
459 if (new_head && show_diffstat) {
460 struct diff_options opts;
461 repo_diff_setup(the_repository, &opts);
462 opts.stat_width = -1; /* use full terminal width */
463 opts.stat_graph_width = -1; /* respect statGraphWidth config */
464 opts.output_format |=
465 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
466 opts.detect_rename = DIFF_DETECT_RENAME;
467 diff_setup_done(&opts);
468 diff_tree_oid(head, new_head, "", &opts);
469 diffcore_std(&opts);
470 diff_flush(&opts);
471 }
472 /* Run a post-merge hook */
474 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
475 strbuf_release(&reflog_message);
477}
478/* Get the name for the merge commit's message. */
480static void merge_name(const char *remote, struct strbuf *msg)
481{
482 struct commit *remote_head;
483 struct object_id branch_head;
484 struct strbuf buf = STRBUF_INIT;
485 struct strbuf bname = STRBUF_INIT;
486 struct merge_remote_desc *desc;
487 const char *ptr;
488 char *found_ref;
489 int len, early;
490 strbuf_branchname(&bname, remote, 0);
492 remote = bname.buf;
493 oidclr(&branch_head);
495 remote_head = get_merge_parent(remote);
496 if (!remote_head)
497 die(_("'%s' does not point to a commit"), remote);
498 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
500 if (starts_with(found_ref, "refs/heads/")) {
501 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
502 oid_to_hex(&branch_head), remote);
503 goto cleanup;
504 }
505 if (starts_with(found_ref, "refs/tags/")) {
506 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
507 oid_to_hex(&branch_head), remote);
508 goto cleanup;
509 }
510 if (starts_with(found_ref, "refs/remotes/")) {
511 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
512 oid_to_hex(&branch_head), remote);
513 goto cleanup;
514 }
515 }
516 /* See if remote matches <name>^^^.. or <name>~<number> */
518 for (len = 0, ptr = remote + strlen(remote);
519 remote < ptr && ptr[-1] == '^';
520 ptr--)
521 len++;
522 if (len)
523 early = 1;
524 else {
525 early = 0;
526 ptr = strrchr(remote, '~');
527 if (ptr) {
528 int seen_nonzero = 0;
529 len++; /* count ~ */
531 while (*++ptr && isdigit(*ptr)) {
532 seen_nonzero |= (*ptr != '0');
533 len++;
534 }
535 if (*ptr)
536 len = 0; /* not ...~<number> */
537 else if (seen_nonzero)
538 early = 1;
539 else if (len == 1)
540 early = 1; /* "name~" is "name~1"! */
541 }
542 }
543 if (len) {
544 struct strbuf truname = STRBUF_INIT;
545 strbuf_addf(&truname, "refs/heads/%s", remote);
546 strbuf_setlen(&truname, truname.len - len);
547 if (ref_exists(truname.buf)) {
548 strbuf_addf(msg,
549 "%s\t\tbranch '%s'%s of .\n",
550 oid_to_hex(&remote_head->object.oid),
551 truname.buf + 11,
552 (early ? " (early part)" : ""));
553 strbuf_release(&truname);
554 goto cleanup;
555 }
556 strbuf_release(&truname);
557 }
558 desc = merge_remote_util(remote_head);
560 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
561 strbuf_addf(msg, "%s\t\t%s '%s'\n",
562 oid_to_hex(&desc->obj->oid),
563 type_name(desc->obj->type),
564 remote);
565 goto cleanup;
566 }
567 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
569 oid_to_hex(&remote_head->object.oid), remote);
570cleanup:
571 strbuf_release(&buf);
572 strbuf_release(&bname);
573}
574static void parse_branch_merge_options(char *bmo)
576{
577 const char **argv;
578 int argc;
579 if (!bmo)
581 return;
582 argc = split_cmdline(bmo, &argv);
583 if (argc < 0)
584 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
585 _(split_cmdline_strerror(argc)));
586 REALLOC_ARRAY(argv, argc + 2);
587 MOVE_ARRAY(argv + 1, argv, argc + 1);
588 argc++;
589 argv[0] = "branch.*.mergeoptions";
590 parse_options(argc, argv, NULL, builtin_merge_options,
591 builtin_merge_usage, 0);
592 free(argv);
593}
594static int git_merge_config(const char *k, const char *v, void *cb)
596{
597 int status;
598 if (branch && starts_with(k, "branch.") &&
600 starts_with(k + 7, branch) &&
601 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
602 free(branch_mergeoptions);
603 branch_mergeoptions = xstrdup(v);
604 return 0;
605 }
606 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
608 show_diffstat = git_config_bool(k, v);
609 else if (!strcmp(k, "merge.verifysignatures"))
610 verify_signatures = git_config_bool(k, v);
611 else if (!strcmp(k, "pull.twohead"))
612 return git_config_string(&pull_twohead, k, v);
613 else if (!strcmp(k, "pull.octopus"))
614 return git_config_string(&pull_octopus, k, v);
615 else if (!strcmp(k, "merge.renormalize"))
616 option_renormalize = git_config_bool(k, v);
617 else if (!strcmp(k, "merge.ff")) {
618 int boolval = git_parse_maybe_bool(v);
619 if (0 <= boolval) {
620 fast_forward = boolval ? FF_ALLOW : FF_NO;
621 } else if (v && !strcmp(v, "only")) {
622 fast_forward = FF_ONLY;
623 } /* do not barf on values from future versions of git */
624 return 0;
625 } else if (!strcmp(k, "merge.defaulttoupstream")) {
626 default_to_upstream = git_config_bool(k, v);
627 return 0;
628 } else if (!strcmp(k, "commit.gpgsign")) {
629 sign_commit = git_config_bool(k, v) ? "" : NULL;
630 return 0;
631 }
632 status = fmt_merge_msg_config(k, v, cb);
634 if (status)
635 return status;
636 status = git_gpg_config(k, v, NULL);
637 if (status)
638 return status;
639 return git_diff_ui_config(k, v, cb);
640}
641static int read_tree_trivial(struct object_id *common, struct object_id *head,
643 struct object_id *one)
644{
645 int i, nr_trees = 0;
646 struct tree *trees[MAX_UNPACK_TREES];
647 struct tree_desc t[MAX_UNPACK_TREES];
648 struct unpack_trees_options opts;
649 memset(&opts, 0, sizeof(opts));
651 opts.head_idx = 2;
652 opts.src_index = &the_index;
653 opts.dst_index = &the_index;
654 opts.update = 1;
655 opts.verbose_update = 1;
656 opts.trivial_merges_only = 1;
657 opts.merge = 1;
658 trees[nr_trees] = parse_tree_indirect(common);
659 if (!trees[nr_trees++])
660 return -1;
661 trees[nr_trees] = parse_tree_indirect(head);
662 if (!trees[nr_trees++])
663 return -1;
664 trees[nr_trees] = parse_tree_indirect(one);
665 if (!trees[nr_trees++])
666 return -1;
667 opts.fn = threeway_merge;
668 cache_tree_free(&active_cache_tree);
669 for (i = 0; i < nr_trees; i++) {
670 parse_tree(trees[i]);
671 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
672 }
673 if (unpack_trees(nr_trees, t, &opts))
674 return -1;
675 return 0;
676}
677static void write_tree_trivial(struct object_id *oid)
679{
680 if (write_cache_as_tree(oid, 0, NULL))
681 die(_("git write-tree failed to write a tree"));
682}
683static int try_merge_strategy(const char *strategy, struct commit_list *common,
685 struct commit_list *remoteheads,
686 struct commit *head)
687{
688 struct lock_file lock = LOCK_INIT;
689 const char *head_arg = "HEAD";
690 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
692 refresh_cache(REFRESH_QUIET);
693 if (write_locked_index(&the_index, &lock,
694 COMMIT_LOCK | SKIP_IF_UNCHANGED))
695 return error(_("Unable to write index."));
696 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
698 int clean, x;
699 struct commit *result;
700 struct commit_list *reversed = NULL;
701 struct merge_options o;
702 struct commit_list *j;
703 if (remoteheads->next) {
705 error(_("Not handling anything other than two heads merge."));
706 return 2;
707 }
708 init_merge_options(&o, the_repository);
710 if (!strcmp(strategy, "subtree"))
711 o.subtree_shift = "";
712 o.renormalize = option_renormalize;
714 o.show_rename_progress =
715 show_progress == -1 ? isatty(2) : show_progress;
716 for (x = 0; x < xopts_nr; x++)
718 if (parse_merge_opt(&o, xopts[x]))
719 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
720 o.branch1 = head_arg;
722 o.branch2 = merge_remote_util(remoteheads->item)->name;
723 for (j = common; j; j = j->next)
725 commit_list_insert(j->item, &reversed);
726 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
728 clean = merge_recursive(&o, head,
729 remoteheads->item, reversed, &result);
730 if (clean < 0)
731 exit(128);
732 if (write_locked_index(&the_index, &lock,
733 COMMIT_LOCK | SKIP_IF_UNCHANGED))
734 die(_("unable to write %s"), get_index_file());
735 return clean ? 0 : 1;
736 } else {
737 return try_merge_command(the_repository,
738 strategy, xopts_nr, xopts,
739 common, head_arg, remoteheads);
740 }
741}
742static void count_diff_files(struct diff_queue_struct *q,
744 struct diff_options *opt, void *data)
745{
746 int *count = data;
747 (*count) += q->nr;
749}
750static int count_unmerged_entries(void)
752{
753 int i, ret = 0;
754 for (i = 0; i < active_nr; i++)
756 if (ce_stage(active_cache[i]))
757 ret++;
758 return ret;
760}
761static void add_strategies(const char *string, unsigned attr)
763{
764 int i;
765 if (string) {
767 struct string_list list = STRING_LIST_INIT_DUP;
768 struct string_list_item *item;
769 string_list_split(&list, string, ' ', -1);
770 for_each_string_list_item(item, &list)
771 append_strategy(get_strategy(item->string));
772 string_list_clear(&list, 0);
773 return;
774 }
775 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
776 if (all_strategy[i].attr & attr)
777 append_strategy(&all_strategy[i]);
778}
780static void read_merge_msg(struct strbuf *msg)
782{
783 const char *filename = git_path_merge_msg(the_repository);
784 strbuf_reset(msg);
785 if (strbuf_read_file(msg, filename, 0) < 0)
786 die_errno(_("Could not read from '%s'"), filename);
787}
788static void write_merge_state(struct commit_list *);
790static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
791{
792 if (err_msg)
793 error("%s", err_msg);
794 fprintf(stderr,
795 _("Not committing merge; use 'git commit' to complete the merge.\n"));
796 write_merge_state(remoteheads);
797 exit(1);
798}
799static const char merge_editor_comment[] =
801N_("Please enter a commit message to explain why this merge is necessary,\n"
802 "especially if it merges an updated upstream into a topic branch.\n"
803 "\n"
804 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
805 "the commit.\n");
806static void write_merge_heads(struct commit_list *);
808static void prepare_to_commit(struct commit_list *remoteheads)
809{
810 struct strbuf msg = STRBUF_INIT;
811 strbuf_addbuf(&msg, &merge_msg);
812 strbuf_addch(&msg, '\n');
813 if (squash)
814 BUG("the control must not reach here under --squash");
815 if (0 < option_edit)
816 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
817 if (signoff)
818 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
819 write_merge_heads(remoteheads);
820 write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
821 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
822 git_path_merge_msg(the_repository), "merge", NULL))
823 abort_commit(remoteheads, NULL);
824 if (0 < option_edit) {
825 if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
826 abort_commit(remoteheads, NULL);
827 }
828 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
830 "commit-msg",
831 git_path_merge_msg(the_repository), NULL))
832 abort_commit(remoteheads, NULL);
833 read_merge_msg(&msg);
835 strbuf_stripspace(&msg, 0 < option_edit);
836 if (!msg.len)
837 abort_commit(remoteheads, _("Empty commit message."));
838 strbuf_release(&merge_msg);
839 strbuf_addbuf(&merge_msg, &msg);
840 strbuf_release(&msg);
841}
842static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
844{
845 struct object_id result_tree, result_commit;
846 struct commit_list *parents, **pptr = &parents;
847 struct lock_file lock = LOCK_INIT;
848 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
850 refresh_cache(REFRESH_QUIET);
851 if (write_locked_index(&the_index, &lock,
852 COMMIT_LOCK | SKIP_IF_UNCHANGED))
853 return error(_("Unable to write index."));
854 write_tree_trivial(&result_tree);
856 printf(_("Wonderful.\n"));
857 pptr = commit_list_append(head, pptr);
858 pptr = commit_list_append(remoteheads->item, pptr);
859 prepare_to_commit(remoteheads);
860 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
861 &result_commit, NULL, sign_commit))
862 die(_("failed to write commit object"));
863 finish(head, remoteheads, &result_commit, "In-index merge");
864 drop_save();
865 return 0;
866}
867static int finish_automerge(struct commit *head,
869 int head_subsumed,
870 struct commit_list *common,
871 struct commit_list *remoteheads,
872 struct object_id *result_tree,
873 const char *wt_strategy)
874{
875 struct commit_list *parents = NULL;
876 struct strbuf buf = STRBUF_INIT;
877 struct object_id result_commit;
878 free_commit_list(common);
880 parents = remoteheads;
881 if (!head_subsumed || fast_forward == FF_NO)
882 commit_list_insert(head, &parents);
883 strbuf_addch(&merge_msg, '\n');
884 prepare_to_commit(remoteheads);
885 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
886 &result_commit, NULL, sign_commit))
887 die(_("failed to write commit object"));
888 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
889 finish(head, remoteheads, &result_commit, buf.buf);
890 strbuf_release(&buf);
891 drop_save();
892 return 0;
893}
894static int suggest_conflicts(void)
896{
897 const char *filename;
898 FILE *fp;
899 struct strbuf msgbuf = STRBUF_INIT;
900 filename = git_path_merge_msg(the_repository);
902 fp = xfopen(filename, "a");
903 append_conflicts_hint(&the_index, &msgbuf);
905 fputs(msgbuf.buf, fp);
906 strbuf_release(&msgbuf);
907 fclose(fp);
908 repo_rerere(the_repository, allow_rerere_auto);
909 printf(_("Automatic merge failed; "
910 "fix conflicts and then commit the result.\n"));
911 return 1;
912}
913static int evaluate_result(void)
915{
916 int cnt = 0;
917 struct rev_info rev;
918 /* Check how many files differ. */
920 repo_init_revisions(the_repository, &rev, "");
921 setup_revisions(0, NULL, &rev, NULL);
922 rev.diffopt.output_format |=
923 DIFF_FORMAT_CALLBACK;
924 rev.diffopt.format_callback = count_diff_files;
925 rev.diffopt.format_callback_data = &cnt;
926 run_diff_files(&rev, 0);
927 /*
929 * Check how many unmerged entries are
930 * there.
931 */
932 cnt += count_unmerged_entries();
933 return cnt;
935}
936/*
938 * Pretend as if the user told us to merge with the remote-tracking
939 * branch we have for the upstream of the current branch
940 */
941static int setup_with_upstream(const char ***argv)
942{
943 struct branch *branch = branch_get(NULL);
944 int i;
945 const char **args;
946 if (!branch)
948 die(_("No current branch."));
949 if (!branch->remote_name)
950 die(_("No remote for the current branch."));
951 if (!branch->merge_nr)
952 die(_("No default upstream defined for the current branch."));
953 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
955 for (i = 0; i < branch->merge_nr; i++) {
956 if (!branch->merge[i]->dst)
957 die(_("No remote-tracking branch for %s from %s"),
958 branch->merge[i]->src, branch->remote_name);
959 args[i] = branch->merge[i]->dst;
960 }
961 args[i] = NULL;
962 *argv = args;
963 return i;
964}
965static void write_merge_heads(struct commit_list *remoteheads)
967{
968 struct commit_list *j;
969 struct strbuf buf = STRBUF_INIT;
970 for (j = remoteheads; j; j = j->next) {
972 struct object_id *oid;
973 struct commit *c = j->item;
974 struct merge_remote_desc *desc;
975 desc = merge_remote_util(c);
977 if (desc && desc->obj) {
978 oid = &desc->obj->oid;
979 } else {
980 oid = &c->object.oid;
981 }
982 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
983 }
984 write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len);
985 strbuf_reset(&buf);
987 if (fast_forward == FF_NO)
988 strbuf_addstr(&buf, "no-ff");
989 write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len);
990 strbuf_release(&buf);
991}
992static void write_merge_state(struct commit_list *remoteheads)
994{
995 write_merge_heads(remoteheads);
996 strbuf_addch(&merge_msg, '\n');
997 write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf,
998 merge_msg.len);
999}
1000static int default_edit_option(void)
1002{
1003 static const char name[] = "GIT_MERGE_AUTOEDIT";
1004 const char *e = getenv(name);
1005 struct stat st_stdin, st_stdout;
1006 if (have_message)
1008 /* an explicit -m msg without --[no-]edit */
1009 return 0;
1010 if (e) {
1012 int v = git_parse_maybe_bool(e);
1013 if (v < 0)
1014 die(_("Bad value '%s' in environment '%s'"), e, name);
1015 return v;
1016 }
1017 /* Use editor if stdin and stdout are the same and is a tty */
1019 return (!fstat(0, &st_stdin) &&
1020 !fstat(1, &st_stdout) &&
1021 isatty(0) && isatty(1) &&
1022 st_stdin.st_dev == st_stdout.st_dev &&
1023 st_stdin.st_ino == st_stdout.st_ino &&
1024 st_stdin.st_mode == st_stdout.st_mode);
1025}
1026static struct commit_list *reduce_parents(struct commit *head_commit,
1028 int *head_subsumed,
1029 struct commit_list *remoteheads)
1030{
1031 struct commit_list *parents, **remotes;
1032 /*
1034 * Is the current HEAD reachable from another commit being
1035 * merged? If so we do not want to record it as a parent of
1036 * the resulting merge, unless --no-ff is given. We will flip
1037 * this variable to 0 when we find HEAD among the independent
1038 * tips being merged.
1039 */
1040 *head_subsumed = 1;
1041 /* Find what parents to record by checking independent ones. */
1043 parents = reduce_heads(remoteheads);
1044 free_commit_list(remoteheads);
1045 remoteheads = NULL;
1047 remotes = &remoteheads;
1048 while (parents) {
1049 struct commit *commit = pop_commit(&parents);
1050 if (commit == head_commit)
1051 *head_subsumed = 0;
1052 else
1053 remotes = &commit_list_insert(commit, remotes)->next;
1054 }
1055 return remoteheads;
1056}
1057static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1059{
1060 struct fmt_merge_msg_opts opts;
1061 memset(&opts, 0, sizeof(opts));
1063 opts.add_title = !have_message;
1064 opts.shortlog_len = shortlog_len;
1065 opts.credit_people = (0 < option_edit);
1066 fmt_merge_msg(merge_names, merge_msg, &opts);
1068 if (merge_msg->len)
1069 strbuf_setlen(merge_msg, merge_msg->len - 1);
1070}
1071static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1073{
1074 const char *filename;
1075 int fd, pos, npos;
1076 struct strbuf fetch_head_file = STRBUF_INIT;
1077 const unsigned hexsz = the_hash_algo->hexsz;
1078 if (!merge_names)
1080 merge_names = &fetch_head_file;
1081 filename = git_path_fetch_head(the_repository);
1083 fd = open(filename, O_RDONLY);
1084 if (fd < 0)
1085 die_errno(_("could not open '%s' for reading"), filename);
1086 if (strbuf_read(merge_names, fd, 0) < 0)
1088 die_errno(_("could not read '%s'"), filename);
1089 if (close(fd) < 0)
1090 die_errno(_("could not close '%s'"), filename);
1091 for (pos = 0; pos < merge_names->len; pos = npos) {
1093 struct object_id oid;
1094 char *ptr;
1095 struct commit *commit;
1096 ptr = strchr(merge_names->buf + pos, '\n');
1098 if (ptr)
1099 npos = ptr - merge_names->buf + 1;
1100 else
1101 npos = merge_names->len;
1102 if (npos - pos < hexsz + 2 ||
1104 get_oid_hex(merge_names->buf + pos, &oid))
1105 commit = NULL; /* bad */
1106 else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2))
1107 continue; /* not-for-merge */
1108 else {
1109 char saved = merge_names->buf[pos + hexsz];
1110 merge_names->buf[pos + hexsz] = '\0';
1111 commit = get_merge_parent(merge_names->buf + pos);
1112 merge_names->buf[pos + hexsz] = saved;
1113 }
1114 if (!commit) {
1115 if (ptr)
1116 *ptr = '\0';
1117 die(_("not something we can merge in %s: %s"),
1118 filename, merge_names->buf + pos);
1119 }
1120 remotes = &commit_list_insert(commit, remotes)->next;
1121 }
1122 if (merge_names == &fetch_head_file)
1124 strbuf_release(&fetch_head_file);
1125}
1126static struct commit_list *collect_parents(struct commit *head_commit,
1128 int *head_subsumed,
1129 int argc, const char **argv,
1130 struct strbuf *merge_msg)
1131{
1132 int i;
1133 struct commit_list *remoteheads = NULL;
1134 struct commit_list **remotes = &remoteheads;
1135 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1136 if (merge_msg && (!have_message || shortlog_len))
1138 autogen = &merge_names;
1139 if (head_commit)
1141 remotes = &commit_list_insert(head_commit, remotes)->next;
1142 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1144 handle_fetch_head(remotes, autogen);
1145 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1146 } else {
1147 for (i = 0; i < argc; i++) {
1148 struct commit *commit = get_merge_parent(argv[i]);
1149 if (!commit)
1150 help_unknown_ref(argv[i], "merge",
1151 _("not something we can merge"));
1152 remotes = &commit_list_insert(commit, remotes)->next;
1153 }
1154 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1155 if (autogen) {
1156 struct commit_list *p;
1157 for (p = remoteheads; p; p = p->next)
1158 merge_name(merge_remote_util(p->item)->name, autogen);
1159 }
1160 }
1161 if (autogen) {
1163 prepare_merge_message(autogen, merge_msg);
1164 strbuf_release(autogen);
1165 }
1166 return remoteheads;
1168}
1169static int merging_a_throwaway_tag(struct commit *commit)
1171{
1172 char *tag_ref;
1173 struct object_id oid;
1174 int is_throwaway_tag = 0;
1175 /* Are we merging a tag? */
1177 if (!merge_remote_util(commit) ||
1178 !merge_remote_util(commit)->obj ||
1179 merge_remote_util(commit)->obj->type != OBJ_TAG)
1180 return is_throwaway_tag;
1181 /*
1183 * Now we know we are merging a tag object. Are we downstream
1184 * and following the tags from upstream? If so, we must have
1185 * the tag object pointed at by "refs/tags/$T" where $T is the
1186 * tagname recorded in the tag object. We want to allow such
1187 * a "just to catch up" merge to fast-forward.
1188 *
1189 * Otherwise, we are playing an integrator's role, making a
1190 * merge with a throw-away tag from a contributor with
1191 * something like "git pull $contributor $signed_tag".
1192 * We want to forbid such a merge from fast-forwarding
1193 * by default; otherwise we would not keep the signature
1194 * anywhere.
1195 */
1196 tag_ref = xstrfmt("refs/tags/%s",
1197 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1198 if (!read_ref(tag_ref, &oid) &&
1199 oideq(&oid, &merge_remote_util(commit)->obj->oid))
1200 is_throwaway_tag = 0;
1201 else
1202 is_throwaway_tag = 1;
1203 free(tag_ref);
1204 return is_throwaway_tag;
1205}
1206int cmd_merge(int argc, const char **argv, const char *prefix)
1208{
1209 struct object_id result_tree, stash, head_oid;
1210 struct commit *head_commit;
1211 struct strbuf buf = STRBUF_INIT;
1212 int i, ret = 0, head_subsumed;
1213 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1214 struct commit_list *common = NULL;
1215 const char *best_strategy = NULL, *wt_strategy = NULL;
1216 struct commit_list *remoteheads, *p;
1217 void *branch_to_free;
1218 int orig_argc = argc;
1219 if (argc == 2 && !strcmp(argv[1], "-h"))
1221 usage_with_options(builtin_merge_usage, builtin_merge_options);
1222 /*
1224 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1225 * current branch.
1226 */
1227 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1228 if (branch)
1229 skip_prefix(branch, "refs/heads/", &branch);
1230 init_diff_ui_defaults();
1232 git_config(git_merge_config, NULL);
1233 if (!branch || is_null_oid(&head_oid))
1235 head_commit = NULL;
1236 else
1237 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1238 if (branch_mergeoptions)
1240 parse_branch_merge_options(branch_mergeoptions);
1241 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1242 builtin_merge_usage, 0);
1243 if (shortlog_len < 0)
1244 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1245 if (verbosity < 0 && show_progress == -1)
1247 show_progress = 0;
1248 if (abort_current_merge) {
1250 int nargc = 2;
1251 const char *nargv[] = {"reset", "--merge", NULL};
1252 if (orig_argc != 2)
1254 usage_msg_opt(_("--abort expects no arguments"),
1255 builtin_merge_usage, builtin_merge_options);
1256 if (!file_exists(git_path_merge_head(the_repository)))
1258 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1259 /* Invoke 'git reset --merge' */
1261 ret = cmd_reset(nargc, nargv, prefix);
1262 goto done;
1263 }
1264 if (continue_current_merge) {
1266 int nargc = 1;
1267 const char *nargv[] = {"commit", NULL};
1268 if (orig_argc != 2)
1270 usage_msg_opt(_("--continue expects no arguments"),
1271 builtin_merge_usage, builtin_merge_options);
1272 if (!file_exists(git_path_merge_head(the_repository)))
1274 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1275 /* Invoke 'git commit' */
1277 ret = cmd_commit(nargc, nargv, prefix);
1278 goto done;
1279 }
1280 if (read_cache_unmerged())
1282 die_resolve_conflict("merge");
1283 if (file_exists(git_path_merge_head(the_repository))) {
1285 /*
1286 * There is no unmerged entry, don't advise 'git
1287 * add/rm <file>', just 'git commit'.
1288 */
1289 if (advice_resolve_conflict)
1290 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1291 "Please, commit your changes before you merge."));
1292 else
1293 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1294 }
1295 if (file_exists(git_path_cherry_pick_head(the_repository))) {
1296 if (advice_resolve_conflict)
1297 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1298 "Please, commit your changes before you merge."));
1299 else
1300 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1301 }
1302 resolve_undo_clear();
1303 if (verbosity < 0)
1305 show_diffstat = 0;
1306 if (squash) {
1308 if (fast_forward == FF_NO)
1309 die(_("You cannot combine --squash with --no-ff."));
1310 option_commit = 0;
1311 }
1312 if (!argc) {
1314 if (default_to_upstream)
1315 argc = setup_with_upstream(&argv);
1316 else
1317 die(_("No commit specified and merge.defaultToUpstream not set."));
1318 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1319 argv[0] = "@{-1}";
1320 }
1321 if (!argc)
1323 usage_with_options(builtin_merge_usage,
1324 builtin_merge_options);
1325 if (!head_commit) {
1327 /*
1328 * If the merged head is a valid one there is no reason
1329 * to forbid "git merge" into a branch yet to be born.
1330 * We do the same for "git pull".
1331 */
1332 struct object_id *remote_head_oid;
1333 if (squash)
1334 die(_("Squash commit into empty head not supported yet"));
1335 if (fast_forward == FF_NO)
1336 die(_("Non-fast-forward commit does not make sense into "
1337 "an empty head"));
1338 remoteheads = collect_parents(head_commit, &head_subsumed,
1339 argc, argv, NULL);
1340 if (!remoteheads)
1341 die(_("%s - not something we can merge"), argv[0]);
1342 if (remoteheads->next)
1343 die(_("Can merge only exactly one commit into empty head"));
1344 if (verify_signatures)
1346 verify_merge_signature(remoteheads->item, verbosity);
1347 remote_head_oid = &remoteheads->item->object.oid;
1349 read_empty(remote_head_oid, 0);
1350 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1351 UPDATE_REFS_DIE_ON_ERR);
1352 goto done;
1353 }
1354 /*
1356 * All the rest are the commits being merged; prepare
1357 * the standard merge summary message to be appended
1358 * to the given message.
1359 */
1360 remoteheads = collect_parents(head_commit, &head_subsumed,
1361 argc, argv, &merge_msg);
1362 if (!head_commit || !argc)
1364 usage_with_options(builtin_merge_usage,
1365 builtin_merge_options);
1366 if (verify_signatures) {
1368 for (p = remoteheads; p; p = p->next) {
1369 verify_merge_signature(p->item, verbosity);
1370 }
1371 }
1372 strbuf_addstr(&buf, "merge");
1374 for (p = remoteheads; p; p = p->next)
1375 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1376 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1377 strbuf_reset(&buf);
1378 for (p = remoteheads; p; p = p->next) {
1380 struct commit *commit = p->item;
1381 strbuf_addf(&buf, "GITHEAD_%s",
1382 oid_to_hex(&commit->object.oid));
1383 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1384 strbuf_reset(&buf);
1385 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1386 fast_forward = FF_NO;
1387 }
1388 if (option_edit < 0)
1390 option_edit = default_edit_option();
1391 if (!use_strategies) {
1393 if (!remoteheads)
1394 ; /* already up-to-date */
1395 else if (!remoteheads->next)
1396 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1397 else
1398 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1399 }
1400 for (i = 0; i < use_strategies_nr; i++) {
1402 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1403 fast_forward = FF_NO;
1404 if (use_strategies[i]->attr & NO_TRIVIAL)
1405 allow_trivial = 0;
1406 }
1407 if (!remoteheads)
1409 ; /* already up-to-date */
1410 else if (!remoteheads->next)
1411 common = get_merge_bases(head_commit, remoteheads->item);
1412 else {
1413 struct commit_list *list = remoteheads;
1414 commit_list_insert(head_commit, &list);
1415 common = get_octopus_merge_bases(list);
1416 free(list);
1417 }
1418 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1420 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1421 if (remoteheads && !common) {
1423 /* No common ancestors found. */
1424 if (!allow_unrelated_histories)
1425 die(_("refusing to merge unrelated histories"));
1426 /* otherwise, we need a real merge. */
1427 } else if (!remoteheads ||
1428 (!remoteheads->next && !common->next &&
1429 common->item == remoteheads->item)) {
1430 /*
1431 * If head can reach all the merge then we are up to date.
1432 * but first the most common case of merging one remote.
1433 */
1434 finish_up_to_date(_("Already up to date."));
1435 goto done;
1436 } else if (fast_forward != FF_NO && !remoteheads->next &&
1437 !common->next &&
1438 oideq(&common->item->object.oid, &head_commit->object.oid)) {
1439 /* Again the most common case of merging one remote. */
1440 struct strbuf msg = STRBUF_INIT;
1441 struct commit *commit;
1442 if (verbosity >= 0) {
1444 printf(_("Updating %s..%s\n"),
1445 find_unique_abbrev(&head_commit->object.oid,
1446 DEFAULT_ABBREV),
1447 find_unique_abbrev(&remoteheads->item->object.oid,
1448 DEFAULT_ABBREV));
1449 }
1450 strbuf_addstr(&msg, "Fast-forward");
1451 if (have_message)
1452 strbuf_addstr(&msg,
1453 " (no commit created; -m option ignored)");
1454 commit = remoteheads->item;
1455 if (!commit) {
1456 ret = 1;
1457 goto done;
1458 }
1459 if (checkout_fast_forward(the_repository,
1461 &head_commit->object.oid,
1462 &commit->object.oid,
1463 overwrite_ignore)) {
1464 ret = 1;
1465 goto done;
1466 }
1467 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1469 drop_save();
1470 goto done;
1471 } else if (!remoteheads->next && common->next)
1472 ;
1473 /*
1474 * We are not doing octopus and not fast-forward. Need
1475 * a real merge.
1476 */
1477 else if (!remoteheads->next && !common->next && option_commit) {
1478 /*
1479 * We are not doing octopus, not fast-forward, and have
1480 * only one common.
1481 */
1482 refresh_cache(REFRESH_QUIET);
1483 if (allow_trivial && fast_forward != FF_ONLY) {
1484 /* See if it is really trivial. */
1485 git_committer_info(IDENT_STRICT);
1486 printf(_("Trying really trivial in-index merge...\n"));
1487 if (!read_tree_trivial(&common->item->object.oid,
1488 &head_commit->object.oid,
1489 &remoteheads->item->object.oid)) {
1490 ret = merge_trivial(head_commit, remoteheads);
1491 goto done;
1492 }
1493 printf(_("Nope.\n"));
1494 }
1495 } else {
1496 /*
1497 * An octopus. If we can reach all the remote we are up
1498 * to date.
1499 */
1500 int up_to_date = 1;
1501 struct commit_list *j;
1502 for (j = remoteheads; j; j = j->next) {
1504 struct commit_list *common_one;
1505 /*
1507 * Here we *have* to calculate the individual
1508 * merge_bases again, otherwise "git merge HEAD^
1509 * HEAD^^" would be missed.
1510 */
1511 common_one = get_merge_bases(head_commit, j->item);
1512 if (!oideq(&common_one->item->object.oid, &j->item->object.oid)) {
1513 up_to_date = 0;
1514 break;
1515 }
1516 }
1517 if (up_to_date) {
1518 finish_up_to_date(_("Already up to date. Yeeah!"));
1519 goto done;
1520 }
1521 }
1522 if (fast_forward == FF_ONLY)
1524 die(_("Not possible to fast-forward, aborting."));
1525 /* We are going to make a new commit. */
1527 git_committer_info(IDENT_STRICT);
1528 /*
1530 * At this point, we need a real merge. No matter what strategy
1531 * we use, it would operate on the index, possibly affecting the
1532 * working tree, and when resolved cleanly, have the desired
1533 * tree in the index -- this means that the index must be in
1534 * sync with the head commit. The strategies are responsible
1535 * to ensure this.
1536 */
1537 if (use_strategies_nr == 1 ||
1538 /*
1539 * Stash away the local changes so that we can try more than one.
1540 */
1541 save_state(&stash))
1542 oidclr(&stash);
1543 for (i = 0; i < use_strategies_nr; i++) {
1545 int ret;
1546 if (i) {
1547 printf(_("Rewinding the tree to pristine...\n"));
1548 restore_state(&head_commit->object.oid, &stash);
1549 }
1550 if (use_strategies_nr != 1)
1551 printf(_("Trying merge strategy %s...\n"),
1552 use_strategies[i]->name);
1553 /*
1554 * Remember which strategy left the state in the working
1555 * tree.
1556 */
1557 wt_strategy = use_strategies[i]->name;
1558 ret = try_merge_strategy(use_strategies[i]->name,
1560 common, remoteheads,
1561 head_commit);
1562 if (!option_commit && !ret) {
1563 merge_was_ok = 1;
1564 /*
1565 * This is necessary here just to avoid writing
1566 * the tree, but later we will *not* exit with
1567 * status code 1 because merge_was_ok is set.
1568 */
1569 ret = 1;
1570 }
1571 if (ret) {
1573 /*
1574 * The backend exits with 1 when conflicts are
1575 * left to be resolved, with 2 when it does not
1576 * handle the given merge at all.
1577 */
1578 if (ret == 1) {
1579 int cnt = evaluate_result();
1580 if (best_cnt <= 0 || cnt <= best_cnt) {
1582 best_strategy = use_strategies[i]->name;
1583 best_cnt = cnt;
1584 }
1585 }
1586 if (merge_was_ok)
1587 break;
1588 else
1589 continue;
1590 }
1591 /* Automerge succeeded. */
1593 write_tree_trivial(&result_tree);
1594 automerge_was_ok = 1;
1595 break;
1596 }
1597 /*
1599 * If we have a resulting tree, that means the strategy module
1600 * auto resolved the merge cleanly.
1601 */
1602 if (automerge_was_ok) {
1603 ret = finish_automerge(head_commit, head_subsumed,
1604 common, remoteheads,
1605 &result_tree, wt_strategy);
1606 goto done;
1607 }
1608 /*
1610 * Pick the result from the best strategy and have the user fix
1611 * it up.
1612 */
1613 if (!best_strategy) {
1614 restore_state(&head_commit->object.oid, &stash);
1615 if (use_strategies_nr > 1)
1616 fprintf(stderr,
1617 _("No merge strategy handled the merge.\n"));
1618 else
1619 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1620 use_strategies[0]->name);
1621 ret = 2;
1622 goto done;
1623 } else if (best_strategy == wt_strategy)
1624 ; /* We already have its result in the working tree. */
1625 else {
1626 printf(_("Rewinding the tree to pristine...\n"));
1627 restore_state(&head_commit->object.oid, &stash);
1628 printf(_("Using the %s to prepare resolving by hand.\n"),
1629 best_strategy);
1630 try_merge_strategy(best_strategy, common, remoteheads,
1631 head_commit);
1632 }
1633 if (squash)
1635 finish(head_commit, remoteheads, NULL, NULL);
1636 else
1637 write_merge_state(remoteheads);
1638 if (merge_was_ok)
1640 fprintf(stderr, _("Automatic merge went well; "
1641 "stopped before committing as requested\n"));
1642 else
1643 ret = suggest_conflicts();
1644done:
1646 free(branch_to_free);
1647 return ret;
1648}