1/*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
6 * Based on git-merge.sh by Junio C Hamano.
7 */
8#include "cache.h"
10#include "parse-options.h"
11#include "builtin.h"
12#include "lockfile.h"
13#include "run-command.h"
14#include "diff.h"
15#include "refs.h"
16#include "commit.h"
17#include "diffcore.h"
18#include "revision.h"
19#include "unpack-trees.h"
20#include "cache-tree.h"
21#include "dir.h"
22#include "utf8.h"
23#include "log-tree.h"
24#include "color.h"
25#include "rerere.h"
26#include "help.h"
27#include "merge-recursive.h"
28#include "resolve-undo.h"
29#include "remote.h"
30#include "fmt-merge-msg.h"
31#include "gpg-interface.h"
32#include "sequencer.h"
33#define DEFAULT_TWOHEAD (1<<0)
35#define DEFAULT_OCTOPUS (1<<1)
36#define NO_FAST_FORWARD (1<<2)
37#define NO_TRIVIAL (1<<3)
38struct strategy {
40 const char *name;
41 unsigned attr;
42};
43static const char * const builtin_merge_usage[] = {
45 N_("git merge [<options>] [<commit>...]"),
46 N_("git merge [<options>] <msg> HEAD <commit>"),
47 N_("git merge --abort"),
48 NULL
49};
50static int show_diffstat = 1, shortlog_len = -1, squash;
52static int option_commit = 1;
53static int option_edit = -1;
54static int allow_trivial = 1, have_message, verify_signatures;
55static int overwrite_ignore = 1;
56static struct strbuf merge_msg = STRBUF_INIT;
57static struct strategy **use_strategies;
58static size_t use_strategies_nr, use_strategies_alloc;
59static const char **xopts;
60static size_t xopts_nr, xopts_alloc;
61static const char *branch;
62static char *branch_mergeoptions;
63static int option_renormalize;
64static int verbosity;
65static int allow_rerere_auto;
66static int abort_current_merge;
67static int allow_unrelated_histories;
68static int show_progress = -1;
69static int default_to_upstream = 1;
70static const char *sign_commit;
71static struct strategy all_strategy[] = {
73 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
74 { "octopus", DEFAULT_OCTOPUS },
75 { "resolve", 0 },
76 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
77 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
78};
79static const char *pull_twohead, *pull_octopus;
81enum ff_type {
83 FF_NO,
84 FF_ALLOW,
85 FF_ONLY
86};
87static enum ff_type fast_forward = FF_ALLOW;
89static int option_parse_message(const struct option *opt,
91 const char *arg, int unset)
92{
93 struct strbuf *buf = opt->value;
94 if (unset)
96 strbuf_setlen(buf, 0);
97 else if (arg) {
98 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
99 have_message = 1;
100 } else
101 return error(_("switch `m' requires a value"));
102 return 0;
103}
104static struct strategy *get_strategy(const char *name)
106{
107 int i;
108 struct strategy *ret;
109 static struct cmdnames main_cmds, other_cmds;
110 static int loaded;
111 if (!name)
113 return NULL;
114 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
116 if (!strcmp(name, all_strategy[i].name))
117 return &all_strategy[i];
118 if (!loaded) {
120 struct cmdnames not_strategies;
121 loaded = 1;
122 memset(¬_strategies, 0, sizeof(struct cmdnames));
124 load_command_list("git-merge-", &main_cmds, &other_cmds);
125 for (i = 0; i < main_cmds.cnt; i++) {
126 int j, found = 0;
127 struct cmdname *ent = main_cmds.names[i];
128 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
129 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
130 && !all_strategy[j].name[ent->len])
131 found = 1;
132 if (!found)
133 add_cmdname(¬_strategies, ent->name, ent->len);
134 }
135 exclude_cmds(&main_cmds, ¬_strategies);
136 }
137 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
138 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
139 fprintf(stderr, _("Available strategies are:"));
140 for (i = 0; i < main_cmds.cnt; i++)
141 fprintf(stderr, " %s", main_cmds.names[i]->name);
142 fprintf(stderr, ".\n");
143 if (other_cmds.cnt) {
144 fprintf(stderr, _("Available custom strategies are:"));
145 for (i = 0; i < other_cmds.cnt; i++)
146 fprintf(stderr, " %s", other_cmds.names[i]->name);
147 fprintf(stderr, ".\n");
148 }
149 exit(1);
150 }
151 ret = xcalloc(1, sizeof(struct strategy));
153 ret->name = xstrdup(name);
154 ret->attr = NO_TRIVIAL;
155 return ret;
156}
157static void append_strategy(struct strategy *s)
159{
160 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
161 use_strategies[use_strategies_nr++] = s;
162}
163static int option_parse_strategy(const struct option *opt,
165 const char *name, int unset)
166{
167 if (unset)
168 return 0;
169 append_strategy(get_strategy(name));
171 return 0;
172}
173static int option_parse_x(const struct option *opt,
175 const char *arg, int unset)
176{
177 if (unset)
178 return 0;
179 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
181 xopts[xopts_nr++] = xstrdup(arg);
182 return 0;
183}
184static int option_parse_n(const struct option *opt,
186 const char *arg, int unset)
187{
188 show_diffstat = unset;
189 return 0;
190}
191static struct option builtin_merge_options[] = {
193 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
194 N_("do not show a diffstat at the end of the merge"),
195 PARSE_OPT_NOARG, option_parse_n },
196 OPT_BOOL(0, "stat", &show_diffstat,
197 N_("show a diffstat at the end of the merge")),
198 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
199 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
200 N_("add (at most <n>) entries from shortlog to merge commit message"),
201 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
202 OPT_BOOL(0, "squash", &squash,
203 N_("create a single commit instead of doing a merge")),
204 OPT_BOOL(0, "commit", &option_commit,
205 N_("perform a commit if the merge succeeds (default)")),
206 OPT_BOOL('e', "edit", &option_edit,
207 N_("edit message before committing")),
208 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
209 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
210 N_("abort if fast-forward is not possible"),
211 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
212 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
213 OPT_BOOL(0, "verify-signatures", &verify_signatures,
214 N_("verify that the named commit has a valid GPG signature")),
215 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
216 N_("merge strategy to use"), option_parse_strategy),
217 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
218 N_("option for selected merge strategy"), option_parse_x),
219 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
220 N_("merge commit message (for a non-fast-forward merge)"),
221 option_parse_message),
222 OPT__VERBOSITY(&verbosity),
223 OPT_BOOL(0, "abort", &abort_current_merge,
224 N_("abort the current in-progress merge")),
225 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
226 N_("allow merging unrelated histories")),
227 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
228 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
229 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
230 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
231 OPT_END()
232};
233/* Cleans up metadata that is uninteresting after a succeeded merge. */
235static void drop_save(void)
236{
237 unlink(git_path_merge_head());
238 unlink(git_path_merge_msg());
239 unlink(git_path_merge_mode());
240}
241static int save_state(unsigned char *stash)
243{
244 int len;
245 struct child_process cp = CHILD_PROCESS_INIT;
246 struct strbuf buffer = STRBUF_INIT;
247 const char *argv[] = {"stash", "create", NULL};
248 cp.argv = argv;
250 cp.out = -1;
251 cp.git_cmd = 1;
252 if (start_command(&cp))
254 die(_("could not run stash."));
255 len = strbuf_read(&buffer, cp.out, 1024);
256 close(cp.out);
257 if (finish_command(&cp) || len < 0)
259 die(_("stash failed"));
260 else if (!len) /* no changes */
261 return -1;
262 strbuf_setlen(&buffer, buffer.len-1);
263 if (get_sha1(buffer.buf, stash))
264 die(_("not a valid object: %s"), buffer.buf);
265 return 0;
266}
267static void read_empty(unsigned const char *sha1, int verbose)
269{
270 int i = 0;
271 const char *args[7];
272 args[i++] = "read-tree";
274 if (verbose)
275 args[i++] = "-v";
276 args[i++] = "-m";
277 args[i++] = "-u";
278 args[i++] = EMPTY_TREE_SHA1_HEX;
279 args[i++] = sha1_to_hex(sha1);
280 args[i] = NULL;
281 if (run_command_v_opt(args, RUN_GIT_CMD))
283 die(_("read-tree failed"));
284}
285static void reset_hard(unsigned const char *sha1, int verbose)
287{
288 int i = 0;
289 const char *args[6];
290 args[i++] = "read-tree";
292 if (verbose)
293 args[i++] = "-v";
294 args[i++] = "--reset";
295 args[i++] = "-u";
296 args[i++] = sha1_to_hex(sha1);
297 args[i] = NULL;
298 if (run_command_v_opt(args, RUN_GIT_CMD))
300 die(_("read-tree failed"));
301}
302static void restore_state(const unsigned char *head,
304 const unsigned char *stash)
305{
306 struct strbuf sb = STRBUF_INIT;
307 const char *args[] = { "stash", "apply", NULL, NULL };
308 if (is_null_sha1(stash))
310 return;
311 reset_hard(head, 1);
313 args[2] = sha1_to_hex(stash);
315 /*
317 * It is OK to ignore error here, for example when there was
318 * nothing to restore.
319 */
320 run_command_v_opt(args, RUN_GIT_CMD);
321 strbuf_release(&sb);
323 refresh_cache(REFRESH_QUIET);
324}
325/* This is called when no merge was necessary. */
327static void finish_up_to_date(const char *msg)
328{
329 if (verbosity >= 0)
330 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
331 drop_save();
332}
333static void squash_message(struct commit *commit, struct commit_list *remoteheads)
335{
336 struct rev_info rev;
337 struct strbuf out = STRBUF_INIT;
338 struct commit_list *j;
339 struct pretty_print_context ctx = {0};
340 printf(_("Squash commit -- not updating HEAD\n"));
342 init_revisions(&rev, NULL);
344 rev.ignore_merges = 1;
345 rev.commit_format = CMIT_FMT_MEDIUM;
346 commit->object.flags |= UNINTERESTING;
348 add_pending_object(&rev, &commit->object, NULL);
349 for (j = remoteheads; j; j = j->next)
351 add_pending_object(&rev, &j->item->object, NULL);
352 setup_revisions(0, NULL, &rev, NULL);
354 if (prepare_revision_walk(&rev))
355 die(_("revision walk setup failed"));
356 ctx.abbrev = rev.abbrev;
358 ctx.date_mode = rev.date_mode;
359 ctx.fmt = rev.commit_format;
360 strbuf_addstr(&out, "Squashed commit of the following:\n");
362 while ((commit = get_revision(&rev)) != NULL) {
363 strbuf_addch(&out, '\n');
364 strbuf_addf(&out, "commit %s\n",
365 oid_to_hex(&commit->object.oid));
366 pretty_print_commit(&ctx, commit, &out);
367 }
368 write_file_buf(git_path_squash_msg(), out.buf, out.len);
369 strbuf_release(&out);
370}
371static void finish(struct commit *head_commit,
373 struct commit_list *remoteheads,
374 const unsigned char *new_head, const char *msg)
375{
376 struct strbuf reflog_message = STRBUF_INIT;
377 const unsigned char *head = head_commit->object.oid.hash;
378 if (!msg)
380 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
381 else {
382 if (verbosity >= 0)
383 printf("%s\n", msg);
384 strbuf_addf(&reflog_message, "%s: %s",
385 getenv("GIT_REFLOG_ACTION"), msg);
386 }
387 if (squash) {
388 squash_message(head_commit, remoteheads);
389 } else {
390 if (verbosity >= 0 && !merge_msg.len)
391 printf(_("No merge message -- not updating HEAD\n"));
392 else {
393 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
394 update_ref(reflog_message.buf, "HEAD",
395 new_head, head, 0,
396 UPDATE_REFS_DIE_ON_ERR);
397 /*
398 * We ignore errors in 'gc --auto', since the
399 * user should see them.
400 */
401 close_all_packs();
402 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
403 }
404 }
405 if (new_head && show_diffstat) {
406 struct diff_options opts;
407 diff_setup(&opts);
408 opts.stat_width = -1; /* use full terminal width */
409 opts.stat_graph_width = -1; /* respect statGraphWidth config */
410 opts.output_format |=
411 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
412 opts.detect_rename = DIFF_DETECT_RENAME;
413 diff_setup_done(&opts);
414 diff_tree_sha1(head, new_head, "", &opts);
415 diffcore_std(&opts);
416 diff_flush(&opts);
417 }
418 /* Run a post-merge hook */
420 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
421 strbuf_release(&reflog_message);
423}
424/* Get the name for the merge commit's message. */
426static void merge_name(const char *remote, struct strbuf *msg)
427{
428 struct commit *remote_head;
429 unsigned char branch_head[20];
430 struct strbuf buf = STRBUF_INIT;
431 struct strbuf bname = STRBUF_INIT;
432 const char *ptr;
433 char *found_ref;
434 int len, early;
435 strbuf_branchname(&bname, remote);
437 remote = bname.buf;
438 memset(branch_head, 0, sizeof(branch_head));
440 remote_head = get_merge_parent(remote);
441 if (!remote_head)
442 die(_("'%s' does not point to a commit"), remote);
443 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
445 if (starts_with(found_ref, "refs/heads/")) {
446 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
447 sha1_to_hex(branch_head), remote);
448 goto cleanup;
449 }
450 if (starts_with(found_ref, "refs/tags/")) {
451 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
452 sha1_to_hex(branch_head), remote);
453 goto cleanup;
454 }
455 if (starts_with(found_ref, "refs/remotes/")) {
456 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
457 sha1_to_hex(branch_head), remote);
458 goto cleanup;
459 }
460 }
461 /* See if remote matches <name>^^^.. or <name>~<number> */
463 for (len = 0, ptr = remote + strlen(remote);
464 remote < ptr && ptr[-1] == '^';
465 ptr--)
466 len++;
467 if (len)
468 early = 1;
469 else {
470 early = 0;
471 ptr = strrchr(remote, '~');
472 if (ptr) {
473 int seen_nonzero = 0;
474 len++; /* count ~ */
476 while (*++ptr && isdigit(*ptr)) {
477 seen_nonzero |= (*ptr != '0');
478 len++;
479 }
480 if (*ptr)
481 len = 0; /* not ...~<number> */
482 else if (seen_nonzero)
483 early = 1;
484 else if (len == 1)
485 early = 1; /* "name~" is "name~1"! */
486 }
487 }
488 if (len) {
489 struct strbuf truname = STRBUF_INIT;
490 strbuf_addf(&truname, "refs/heads/%s", remote);
491 strbuf_setlen(&truname, truname.len - len);
492 if (ref_exists(truname.buf)) {
493 strbuf_addf(msg,
494 "%s\t\tbranch '%s'%s of .\n",
495 oid_to_hex(&remote_head->object.oid),
496 truname.buf + 11,
497 (early ? " (early part)" : ""));
498 strbuf_release(&truname);
499 goto cleanup;
500 }
501 strbuf_release(&truname);
502 }
503 if (remote_head->util) {
505 struct merge_remote_desc *desc;
506 desc = merge_remote_util(remote_head);
507 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
508 strbuf_addf(msg, "%s\t\t%s '%s'\n",
509 oid_to_hex(&desc->obj->oid),
510 typename(desc->obj->type),
511 remote);
512 goto cleanup;
513 }
514 }
515 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
517 oid_to_hex(&remote_head->object.oid), remote);
518cleanup:
519 strbuf_release(&buf);
520 strbuf_release(&bname);
521}
522static void parse_branch_merge_options(char *bmo)
524{
525 const char **argv;
526 int argc;
527 if (!bmo)
529 return;
530 argc = split_cmdline(bmo, &argv);
531 if (argc < 0)
532 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
533 split_cmdline_strerror(argc));
534 REALLOC_ARRAY(argv, argc + 2);
535 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
536 argc++;
537 argv[0] = "branch.*.mergeoptions";
538 parse_options(argc, argv, NULL, builtin_merge_options,
539 builtin_merge_usage, 0);
540 free(argv);
541}
542static int git_merge_config(const char *k, const char *v, void *cb)
544{
545 int status;
546 if (branch && starts_with(k, "branch.") &&
548 starts_with(k + 7, branch) &&
549 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
550 free(branch_mergeoptions);
551 branch_mergeoptions = xstrdup(v);
552 return 0;
553 }
554 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
556 show_diffstat = git_config_bool(k, v);
557 else if (!strcmp(k, "pull.twohead"))
558 return git_config_string(&pull_twohead, k, v);
559 else if (!strcmp(k, "pull.octopus"))
560 return git_config_string(&pull_octopus, k, v);
561 else if (!strcmp(k, "merge.renormalize"))
562 option_renormalize = git_config_bool(k, v);
563 else if (!strcmp(k, "merge.ff")) {
564 int boolval = git_config_maybe_bool(k, v);
565 if (0 <= boolval) {
566 fast_forward = boolval ? FF_ALLOW : FF_NO;
567 } else if (v && !strcmp(v, "only")) {
568 fast_forward = FF_ONLY;
569 } /* do not barf on values from future versions of git */
570 return 0;
571 } else if (!strcmp(k, "merge.defaulttoupstream")) {
572 default_to_upstream = git_config_bool(k, v);
573 return 0;
574 } else if (!strcmp(k, "commit.gpgsign")) {
575 sign_commit = git_config_bool(k, v) ? "" : NULL;
576 return 0;
577 }
578 status = fmt_merge_msg_config(k, v, cb);
580 if (status)
581 return status;
582 status = git_gpg_config(k, v, NULL);
583 if (status)
584 return status;
585 return git_diff_ui_config(k, v, cb);
586}
587static int read_tree_trivial(unsigned char *common, unsigned char *head,
589 unsigned char *one)
590{
591 int i, nr_trees = 0;
592 struct tree *trees[MAX_UNPACK_TREES];
593 struct tree_desc t[MAX_UNPACK_TREES];
594 struct unpack_trees_options opts;
595 memset(&opts, 0, sizeof(opts));
597 opts.head_idx = 2;
598 opts.src_index = &the_index;
599 opts.dst_index = &the_index;
600 opts.update = 1;
601 opts.verbose_update = 1;
602 opts.trivial_merges_only = 1;
603 opts.merge = 1;
604 trees[nr_trees] = parse_tree_indirect(common);
605 if (!trees[nr_trees++])
606 return -1;
607 trees[nr_trees] = parse_tree_indirect(head);
608 if (!trees[nr_trees++])
609 return -1;
610 trees[nr_trees] = parse_tree_indirect(one);
611 if (!trees[nr_trees++])
612 return -1;
613 opts.fn = threeway_merge;
614 cache_tree_free(&active_cache_tree);
615 for (i = 0; i < nr_trees; i++) {
616 parse_tree(trees[i]);
617 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
618 }
619 if (unpack_trees(nr_trees, t, &opts))
620 return -1;
621 return 0;
622}
623static void write_tree_trivial(unsigned char *sha1)
625{
626 if (write_cache_as_tree(sha1, 0, NULL))
627 die(_("git write-tree failed to write a tree"));
628}
629static int try_merge_strategy(const char *strategy, struct commit_list *common,
631 struct commit_list *remoteheads,
632 struct commit *head, const char *head_arg)
633{
634 static struct lock_file lock;
635 hold_locked_index(&lock, 1);
637 refresh_cache(REFRESH_QUIET);
638 if (active_cache_changed &&
639 write_locked_index(&the_index, &lock, COMMIT_LOCK))
640 return error(_("Unable to write index."));
641 rollback_lock_file(&lock);
642 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
644 int clean, x;
645 struct commit *result;
646 struct commit_list *reversed = NULL;
647 struct merge_options o;
648 struct commit_list *j;
649 if (remoteheads->next) {
651 error(_("Not handling anything other than two heads merge."));
652 return 2;
653 }
654 init_merge_options(&o);
656 if (!strcmp(strategy, "subtree"))
657 o.subtree_shift = "";
658 o.renormalize = option_renormalize;
660 o.show_rename_progress =
661 show_progress == -1 ? isatty(2) : show_progress;
662 for (x = 0; x < xopts_nr; x++)
664 if (parse_merge_opt(&o, xopts[x]))
665 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
666 o.branch1 = head_arg;
668 o.branch2 = merge_remote_util(remoteheads->item)->name;
669 for (j = common; j; j = j->next)
671 commit_list_insert(j->item, &reversed);
672 hold_locked_index(&lock, 1);
674 clean = merge_recursive(&o, head,
675 remoteheads->item, reversed, &result);
676 if (active_cache_changed &&
677 write_locked_index(&the_index, &lock, COMMIT_LOCK))
678 die (_("unable to write %s"), get_index_file());
679 rollback_lock_file(&lock);
680 return clean ? 0 : 1;
681 } else {
682 return try_merge_command(strategy, xopts_nr, xopts,
683 common, head_arg, remoteheads);
684 }
685}
686static void count_diff_files(struct diff_queue_struct *q,
688 struct diff_options *opt, void *data)
689{
690 int *count = data;
691 (*count) += q->nr;
693}
694static int count_unmerged_entries(void)
696{
697 int i, ret = 0;
698 for (i = 0; i < active_nr; i++)
700 if (ce_stage(active_cache[i]))
701 ret++;
702 return ret;
704}
705static void split_merge_strategies(const char *string, struct strategy **list,
707 int *nr, int *alloc)
708{
709 char *p, *q, *buf;
710 if (!string)
712 return;
713 buf = xstrdup(string);
715 q = buf;
716 for (;;) {
717 p = strchr(q, ' ');
718 if (!p) {
719 ALLOC_GROW(*list, *nr + 1, *alloc);
720 (*list)[(*nr)++].name = xstrdup(q);
721 free(buf);
722 return;
723 } else {
724 *p = '\0';
725 ALLOC_GROW(*list, *nr + 1, *alloc);
726 (*list)[(*nr)++].name = xstrdup(q);
727 q = ++p;
728 }
729 }
730}
731static void add_strategies(const char *string, unsigned attr)
733{
734 struct strategy *list = NULL;
735 int list_alloc = 0, list_nr = 0, i;
736 memset(&list, 0, sizeof(list));
738 split_merge_strategies(string, &list, &list_nr, &list_alloc);
739 if (list) {
740 for (i = 0; i < list_nr; i++)
741 append_strategy(get_strategy(list[i].name));
742 return;
743 }
744 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
745 if (all_strategy[i].attr & attr)
746 append_strategy(&all_strategy[i]);
747}
749static void read_merge_msg(struct strbuf *msg)
751{
752 const char *filename = git_path_merge_msg();
753 strbuf_reset(msg);
754 if (strbuf_read_file(msg, filename, 0) < 0)
755 die_errno(_("Could not read from '%s'"), filename);
756}
757static void write_merge_state(struct commit_list *);
759static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
760{
761 if (err_msg)
762 error("%s", err_msg);
763 fprintf(stderr,
764 _("Not committing merge; use 'git commit' to complete the merge.\n"));
765 write_merge_state(remoteheads);
766 exit(1);
767}
768static const char merge_editor_comment[] =
770N_("Please enter a commit message to explain why this merge is necessary,\n"
771 "especially if it merges an updated upstream into a topic branch.\n"
772 "\n"
773 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
774 "the commit.\n");
775static void prepare_to_commit(struct commit_list *remoteheads)
777{
778 struct strbuf msg = STRBUF_INIT;
779 strbuf_addbuf(&msg, &merge_msg);
780 strbuf_addch(&msg, '\n');
781 if (0 < option_edit)
782 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
783 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
784 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
785 git_path_merge_msg(), "merge", NULL))
786 abort_commit(remoteheads, NULL);
787 if (0 < option_edit) {
788 if (launch_editor(git_path_merge_msg(), NULL, NULL))
789 abort_commit(remoteheads, NULL);
790 }
791 read_merge_msg(&msg);
792 strbuf_stripspace(&msg, 0 < option_edit);
793 if (!msg.len)
794 abort_commit(remoteheads, _("Empty commit message."));
795 strbuf_release(&merge_msg);
796 strbuf_addbuf(&merge_msg, &msg);
797 strbuf_release(&msg);
798}
799static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
801{
802 unsigned char result_tree[20], result_commit[20];
803 struct commit_list *parents, **pptr = &parents;
804 static struct lock_file lock;
805 hold_locked_index(&lock, 1);
807 refresh_cache(REFRESH_QUIET);
808 if (active_cache_changed &&
809 write_locked_index(&the_index, &lock, COMMIT_LOCK))
810 return error(_("Unable to write index."));
811 rollback_lock_file(&lock);
812 write_tree_trivial(result_tree);
814 printf(_("Wonderful.\n"));
815 pptr = commit_list_append(head, pptr);
816 pptr = commit_list_append(remoteheads->item, pptr);
817 prepare_to_commit(remoteheads);
818 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
819 result_commit, NULL, sign_commit))
820 die(_("failed to write commit object"));
821 finish(head, remoteheads, result_commit, "In-index merge");
822 drop_save();
823 return 0;
824}
825static int finish_automerge(struct commit *head,
827 int head_subsumed,
828 struct commit_list *common,
829 struct commit_list *remoteheads,
830 unsigned char *result_tree,
831 const char *wt_strategy)
832{
833 struct commit_list *parents = NULL;
834 struct strbuf buf = STRBUF_INIT;
835 unsigned char result_commit[20];
836 free_commit_list(common);
838 parents = remoteheads;
839 if (!head_subsumed || fast_forward == FF_NO)
840 commit_list_insert(head, &parents);
841 strbuf_addch(&merge_msg, '\n');
842 prepare_to_commit(remoteheads);
843 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
844 result_commit, NULL, sign_commit))
845 die(_("failed to write commit object"));
846 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
847 finish(head, remoteheads, result_commit, buf.buf);
848 strbuf_release(&buf);
849 drop_save();
850 return 0;
851}
852static int suggest_conflicts(void)
854{
855 const char *filename;
856 FILE *fp;
857 struct strbuf msgbuf = STRBUF_INIT;
858 filename = git_path_merge_msg();
860 fp = fopen(filename, "a");
861 if (!fp)
862 die_errno(_("Could not open '%s' for writing"), filename);
863 append_conflicts_hint(&msgbuf);
865 fputs(msgbuf.buf, fp);
866 strbuf_release(&msgbuf);
867 fclose(fp);
868 rerere(allow_rerere_auto);
869 printf(_("Automatic merge failed; "
870 "fix conflicts and then commit the result.\n"));
871 return 1;
872}
873static struct commit *is_old_style_invocation(int argc, const char **argv,
875 const unsigned char *head)
876{
877 struct commit *second_token = NULL;
878 if (argc > 2) {
879 unsigned char second_sha1[20];
880 if (get_sha1(argv[1], second_sha1))
882 return NULL;
883 second_token = lookup_commit_reference_gently(second_sha1, 0);
884 if (!second_token)
885 die(_("'%s' is not a commit"), argv[1]);
886 if (hashcmp(second_token->object.oid.hash, head))
887 return NULL;
888 }
889 return second_token;
890}
891static int evaluate_result(void)
893{
894 int cnt = 0;
895 struct rev_info rev;
896 /* Check how many files differ. */
898 init_revisions(&rev, "");
899 setup_revisions(0, NULL, &rev, NULL);
900 rev.diffopt.output_format |=
901 DIFF_FORMAT_CALLBACK;
902 rev.diffopt.format_callback = count_diff_files;
903 rev.diffopt.format_callback_data = &cnt;
904 run_diff_files(&rev, 0);
905 /*
907 * Check how many unmerged entries are
908 * there.
909 */
910 cnt += count_unmerged_entries();
911 return cnt;
913}
914/*
916 * Pretend as if the user told us to merge with the remote-tracking
917 * branch we have for the upstream of the current branch
918 */
919static int setup_with_upstream(const char ***argv)
920{
921 struct branch *branch = branch_get(NULL);
922 int i;
923 const char **args;
924 if (!branch)
926 die(_("No current branch."));
927 if (!branch->remote_name)
928 die(_("No remote for the current branch."));
929 if (!branch->merge_nr)
930 die(_("No default upstream defined for the current branch."));
931 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
933 for (i = 0; i < branch->merge_nr; i++) {
934 if (!branch->merge[i]->dst)
935 die(_("No remote-tracking branch for %s from %s"),
936 branch->merge[i]->src, branch->remote_name);
937 args[i] = branch->merge[i]->dst;
938 }
939 args[i] = NULL;
940 *argv = args;
941 return i;
942}
943static void write_merge_state(struct commit_list *remoteheads)
945{
946 struct commit_list *j;
947 struct strbuf buf = STRBUF_INIT;
948 for (j = remoteheads; j; j = j->next) {
950 struct object_id *oid;
951 struct commit *c = j->item;
952 if (c->util && merge_remote_util(c)->obj) {
953 oid = &merge_remote_util(c)->obj->oid;
954 } else {
955 oid = &c->object.oid;
956 }
957 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
958 }
959 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
960 strbuf_addch(&merge_msg, '\n');
961 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
962 strbuf_reset(&buf);
964 if (fast_forward == FF_NO)
965 strbuf_addf(&buf, "no-ff");
966 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
967}
968static int default_edit_option(void)
970{
971 static const char name[] = "GIT_MERGE_AUTOEDIT";
972 const char *e = getenv(name);
973 struct stat st_stdin, st_stdout;
974 if (have_message)
976 /* an explicit -m msg without --[no-]edit */
977 return 0;
978 if (e) {
980 int v = git_config_maybe_bool(name, e);
981 if (v < 0)
982 die(_("Bad value '%s' in environment '%s'"), e, name);
983 return v;
984 }
985 /* Use editor if stdin and stdout are the same and is a tty */
987 return (!fstat(0, &st_stdin) &&
988 !fstat(1, &st_stdout) &&
989 isatty(0) && isatty(1) &&
990 st_stdin.st_dev == st_stdout.st_dev &&
991 st_stdin.st_ino == st_stdout.st_ino &&
992 st_stdin.st_mode == st_stdout.st_mode);
993}
994static struct commit_list *reduce_parents(struct commit *head_commit,
996 int *head_subsumed,
997 struct commit_list *remoteheads)
998{
999 struct commit_list *parents, **remotes;
1000 /*
1002 * Is the current HEAD reachable from another commit being
1003 * merged? If so we do not want to record it as a parent of
1004 * the resulting merge, unless --no-ff is given. We will flip
1005 * this variable to 0 when we find HEAD among the independent
1006 * tips being merged.
1007 */
1008 *head_subsumed = 1;
1009 /* Find what parents to record by checking independent ones. */
1011 parents = reduce_heads(remoteheads);
1012 remoteheads = NULL;
1014 remotes = &remoteheads;
1015 while (parents) {
1016 struct commit *commit = pop_commit(&parents);
1017 if (commit == head_commit)
1018 *head_subsumed = 0;
1019 else
1020 remotes = &commit_list_insert(commit, remotes)->next;
1021 }
1022 return remoteheads;
1023}
1024static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1026{
1027 struct fmt_merge_msg_opts opts;
1028 memset(&opts, 0, sizeof(opts));
1030 opts.add_title = !have_message;
1031 opts.shortlog_len = shortlog_len;
1032 opts.credit_people = (0 < option_edit);
1033 fmt_merge_msg(merge_names, merge_msg, &opts);
1035 if (merge_msg->len)
1036 strbuf_setlen(merge_msg, merge_msg->len - 1);
1037}
1038static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1040{
1041 const char *filename;
1042 int fd, pos, npos;
1043 struct strbuf fetch_head_file = STRBUF_INIT;
1044 if (!merge_names)
1046 merge_names = &fetch_head_file;
1047 filename = git_path_fetch_head();
1049 fd = open(filename, O_RDONLY);
1050 if (fd < 0)
1051 die_errno(_("could not open '%s' for reading"), filename);
1052 if (strbuf_read(merge_names, fd, 0) < 0)
1054 die_errno(_("could not read '%s'"), filename);
1055 if (close(fd) < 0)
1056 die_errno(_("could not close '%s'"), filename);
1057 for (pos = 0; pos < merge_names->len; pos = npos) {
1059 unsigned char sha1[20];
1060 char *ptr;
1061 struct commit *commit;
1062 ptr = strchr(merge_names->buf + pos, '\n');
1064 if (ptr)
1065 npos = ptr - merge_names->buf + 1;
1066 else
1067 npos = merge_names->len;
1068 if (npos - pos < 40 + 2 ||
1070 get_sha1_hex(merge_names->buf + pos, sha1))
1071 commit = NULL; /* bad */
1072 else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
1073 continue; /* not-for-merge */
1074 else {
1075 char saved = merge_names->buf[pos + 40];
1076 merge_names->buf[pos + 40] = '\0';
1077 commit = get_merge_parent(merge_names->buf + pos);
1078 merge_names->buf[pos + 40] = saved;
1079 }
1080 if (!commit) {
1081 if (ptr)
1082 *ptr = '\0';
1083 die(_("not something we can merge in %s: %s"),
1084 filename, merge_names->buf + pos);
1085 }
1086 remotes = &commit_list_insert(commit, remotes)->next;
1087 }
1088 if (merge_names == &fetch_head_file)
1090 strbuf_release(&fetch_head_file);
1091}
1092static struct commit_list *collect_parents(struct commit *head_commit,
1094 int *head_subsumed,
1095 int argc, const char **argv,
1096 struct strbuf *merge_msg)
1097{
1098 int i;
1099 struct commit_list *remoteheads = NULL;
1100 struct commit_list **remotes = &remoteheads;
1101 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1102 if (merge_msg && (!have_message || shortlog_len))
1104 autogen = &merge_names;
1105 if (head_commit)
1107 remotes = &commit_list_insert(head_commit, remotes)->next;
1108 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1110 handle_fetch_head(remotes, autogen);
1111 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1112 } else {
1113 for (i = 0; i < argc; i++) {
1114 struct commit *commit = get_merge_parent(argv[i]);
1115 if (!commit)
1116 help_unknown_ref(argv[i], "merge",
1117 _("not something we can merge"));
1118 remotes = &commit_list_insert(commit, remotes)->next;
1119 }
1120 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1121 if (autogen) {
1122 struct commit_list *p;
1123 for (p = remoteheads; p; p = p->next)
1124 merge_name(merge_remote_util(p->item)->name, autogen);
1125 }
1126 }
1127 if (autogen) {
1129 prepare_merge_message(autogen, merge_msg);
1130 strbuf_release(autogen);
1131 }
1132 return remoteheads;
1134}
1135int cmd_merge(int argc, const char **argv, const char *prefix)
1137{
1138 unsigned char result_tree[20];
1139 unsigned char stash[20];
1140 unsigned char head_sha1[20];
1141 struct commit *head_commit;
1142 struct strbuf buf = STRBUF_INIT;
1143 const char *head_arg;
1144 int i, ret = 0, head_subsumed;
1145 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1146 struct commit_list *common = NULL;
1147 const char *best_strategy = NULL, *wt_strategy = NULL;
1148 struct commit_list *remoteheads, *p;
1149 void *branch_to_free;
1150 if (argc == 2 && !strcmp(argv[1], "-h"))
1152 usage_with_options(builtin_merge_usage, builtin_merge_options);
1153 /*
1155 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1156 * current branch.
1157 */
1158 branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, NULL);
1159 if (branch && starts_with(branch, "refs/heads/"))
1160 branch += 11;
1161 if (!branch || is_null_sha1(head_sha1))
1162 head_commit = NULL;
1163 else
1164 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1165 init_diff_ui_defaults();
1167 git_config(git_merge_config, NULL);
1168 if (branch_mergeoptions)
1170 parse_branch_merge_options(branch_mergeoptions);
1171 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1172 builtin_merge_usage, 0);
1173 if (shortlog_len < 0)
1174 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1175 if (verbosity < 0 && show_progress == -1)
1177 show_progress = 0;
1178 if (abort_current_merge) {
1180 int nargc = 2;
1181 const char *nargv[] = {"reset", "--merge", NULL};
1182 if (!file_exists(git_path_merge_head()))
1184 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1185 /* Invoke 'git reset --merge' */
1187 ret = cmd_reset(nargc, nargv, prefix);
1188 goto done;
1189 }
1190 if (read_cache_unmerged())
1192 die_resolve_conflict("merge");
1193 if (file_exists(git_path_merge_head())) {
1195 /*
1196 * There is no unmerged entry, don't advise 'git
1197 * add/rm <file>', just 'git commit'.
1198 */
1199 if (advice_resolve_conflict)
1200 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1201 "Please, commit your changes before you merge."));
1202 else
1203 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1204 }
1205 if (file_exists(git_path_cherry_pick_head())) {
1206 if (advice_resolve_conflict)
1207 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1208 "Please, commit your changes before you merge."));
1209 else
1210 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1211 }
1212 resolve_undo_clear();
1213 if (verbosity < 0)
1215 show_diffstat = 0;
1216 if (squash) {
1218 if (fast_forward == FF_NO)
1219 die(_("You cannot combine --squash with --no-ff."));
1220 option_commit = 0;
1221 }
1222 if (!argc) {
1224 if (default_to_upstream)
1225 argc = setup_with_upstream(&argv);
1226 else
1227 die(_("No commit specified and merge.defaultToUpstream not set."));
1228 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1229 argv[0] = "@{-1}";
1230 }
1231 if (!argc)
1233 usage_with_options(builtin_merge_usage,
1234 builtin_merge_options);
1235 if (!head_commit) {
1237 /*
1238 * If the merged head is a valid one there is no reason
1239 * to forbid "git merge" into a branch yet to be born.
1240 * We do the same for "git pull".
1241 */
1242 unsigned char *remote_head_sha1;
1243 if (squash)
1244 die(_("Squash commit into empty head not supported yet"));
1245 if (fast_forward == FF_NO)
1246 die(_("Non-fast-forward commit does not make sense into "
1247 "an empty head"));
1248 remoteheads = collect_parents(head_commit, &head_subsumed,
1249 argc, argv, NULL);
1250 if (!remoteheads)
1251 die(_("%s - not something we can merge"), argv[0]);
1252 if (remoteheads->next)
1253 die(_("Can merge only exactly one commit into empty head"));
1254 remote_head_sha1 = remoteheads->item->object.oid.hash;
1255 read_empty(remote_head_sha1, 0);
1256 update_ref("initial pull", "HEAD", remote_head_sha1,
1257 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1258 goto done;
1259 }
1260 /*
1262 * This could be traditional "merge <msg> HEAD <commit>..." and
1263 * the way we can tell it is to see if the second token is HEAD,
1264 * but some people might have misused the interface and used a
1265 * commit-ish that is the same as HEAD there instead.
1266 * Traditional format never would have "-m" so it is an
1267 * additional safety measure to check for it.
1268 */
1269 if (!have_message &&
1270 is_old_style_invocation(argc, argv, head_commit->object.oid.hash)) {
1271 warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
1272 strbuf_addstr(&merge_msg, argv[0]);
1273 head_arg = argv[1];
1274 argv += 2;
1275 argc -= 2;
1276 remoteheads = collect_parents(head_commit, &head_subsumed,
1277 argc, argv, NULL);
1278 } else {
1279 /* We are invoked directly as the first-class UI. */
1280 head_arg = "HEAD";
1281 /*
1283 * All the rest are the commits being merged; prepare
1284 * the standard merge summary message to be appended
1285 * to the given message.
1286 */
1287 remoteheads = collect_parents(head_commit, &head_subsumed,
1288 argc, argv, &merge_msg);
1289 }
1290 if (!head_commit || !argc)
1292 usage_with_options(builtin_merge_usage,
1293 builtin_merge_options);
1294 if (verify_signatures) {
1296 for (p = remoteheads; p; p = p->next) {
1297 struct commit *commit = p->item;
1298 char hex[GIT_SHA1_HEXSZ + 1];
1299 struct signature_check signature_check;
1300 memset(&signature_check, 0, sizeof(signature_check));
1301 check_commit_signature(commit, &signature_check);
1303 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1305 switch (signature_check.result) {
1306 case 'G':
1307 break;
1308 case 'U':
1309 die(_("Commit %s has an untrusted GPG signature, "
1310 "allegedly by %s."), hex, signature_check.signer);
1311 case 'B':
1312 die(_("Commit %s has a bad GPG signature "
1313 "allegedly by %s."), hex, signature_check.signer);
1314 default: /* 'N' */
1315 die(_("Commit %s does not have a GPG signature."), hex);
1316 }
1317 if (verbosity >= 0 && signature_check.result == 'G')
1318 printf(_("Commit %s has a good GPG signature by %s\n"),
1319 hex, signature_check.signer);
1320 signature_check_clear(&signature_check);
1322 }
1323 }
1324 strbuf_addstr(&buf, "merge");
1326 for (p = remoteheads; p; p = p->next)
1327 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1328 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1329 strbuf_reset(&buf);
1330 for (p = remoteheads; p; p = p->next) {
1332 struct commit *commit = p->item;
1333 strbuf_addf(&buf, "GITHEAD_%s",
1334 oid_to_hex(&commit->object.oid));
1335 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1336 strbuf_reset(&buf);
1337 if (fast_forward != FF_ONLY &&
1338 merge_remote_util(commit) &&
1339 merge_remote_util(commit)->obj &&
1340 merge_remote_util(commit)->obj->type == OBJ_TAG)
1341 fast_forward = FF_NO;
1342 }
1343 if (option_edit < 0)
1345 option_edit = default_edit_option();
1346 if (!use_strategies) {
1348 if (!remoteheads)
1349 ; /* already up-to-date */
1350 else if (!remoteheads->next)
1351 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1352 else
1353 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1354 }
1355 for (i = 0; i < use_strategies_nr; i++) {
1357 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1358 fast_forward = FF_NO;
1359 if (use_strategies[i]->attr & NO_TRIVIAL)
1360 allow_trivial = 0;
1361 }
1362 if (!remoteheads)
1364 ; /* already up-to-date */
1365 else if (!remoteheads->next)
1366 common = get_merge_bases(head_commit, remoteheads->item);
1367 else {
1368 struct commit_list *list = remoteheads;
1369 commit_list_insert(head_commit, &list);
1370 common = get_octopus_merge_bases(list);
1371 free(list);
1372 }
1373 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
1375 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1376 if (remoteheads && !common) {
1378 /* No common ancestors found. */
1379 if (!allow_unrelated_histories)
1380 die(_("refusing to merge unrelated histories"));
1381 /* otherwise, we need a real merge. */
1382 } else if (!remoteheads ||
1383 (!remoteheads->next && !common->next &&
1384 common->item == remoteheads->item)) {
1385 /*
1386 * If head can reach all the merge then we are up to date.
1387 * but first the most common case of merging one remote.
1388 */
1389 finish_up_to_date(_("Already up-to-date."));
1390 goto done;
1391 } else if (fast_forward != FF_NO && !remoteheads->next &&
1392 !common->next &&
1393 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1394 /* Again the most common case of merging one remote. */
1395 struct strbuf msg = STRBUF_INIT;
1396 struct commit *commit;
1397 if (verbosity >= 0) {
1399 char from[GIT_SHA1_HEXSZ + 1], to[GIT_SHA1_HEXSZ + 1];
1400 find_unique_abbrev_r(from, head_commit->object.oid.hash,
1401 DEFAULT_ABBREV);
1402 find_unique_abbrev_r(to, remoteheads->item->object.oid.hash,
1403 DEFAULT_ABBREV);
1404 printf(_("Updating %s..%s\n"), from, to);
1405 }
1406 strbuf_addstr(&msg, "Fast-forward");
1407 if (have_message)
1408 strbuf_addstr(&msg,
1409 " (no commit created; -m option ignored)");
1410 commit = remoteheads->item;
1411 if (!commit) {
1412 ret = 1;
1413 goto done;
1414 }
1415 if (checkout_fast_forward(head_commit->object.oid.hash,
1417 commit->object.oid.hash,
1418 overwrite_ignore)) {
1419 ret = 1;
1420 goto done;
1421 }
1422 finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
1424 drop_save();
1425 goto done;
1426 } else if (!remoteheads->next && common->next)
1427 ;
1428 /*
1429 * We are not doing octopus and not fast-forward. Need
1430 * a real merge.
1431 */
1432 else if (!remoteheads->next && !common->next && option_commit) {
1433 /*
1434 * We are not doing octopus, not fast-forward, and have
1435 * only one common.
1436 */
1437 refresh_cache(REFRESH_QUIET);
1438 if (allow_trivial && fast_forward != FF_ONLY) {
1439 /* See if it is really trivial. */
1440 git_committer_info(IDENT_STRICT);
1441 printf(_("Trying really trivial in-index merge...\n"));
1442 if (!read_tree_trivial(common->item->object.oid.hash,
1443 head_commit->object.oid.hash,
1444 remoteheads->item->object.oid.hash)) {
1445 ret = merge_trivial(head_commit, remoteheads);
1446 goto done;
1447 }
1448 printf(_("Nope.\n"));
1449 }
1450 } else {
1451 /*
1452 * An octopus. If we can reach all the remote we are up
1453 * to date.
1454 */
1455 int up_to_date = 1;
1456 struct commit_list *j;
1457 for (j = remoteheads; j; j = j->next) {
1459 struct commit_list *common_one;
1460 /*
1462 * Here we *have* to calculate the individual
1463 * merge_bases again, otherwise "git merge HEAD^
1464 * HEAD^^" would be missed.
1465 */
1466 common_one = get_merge_bases(head_commit, j->item);
1467 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1468 up_to_date = 0;
1469 break;
1470 }
1471 }
1472 if (up_to_date) {
1473 finish_up_to_date(_("Already up-to-date. Yeeah!"));
1474 goto done;
1475 }
1476 }
1477 if (fast_forward == FF_ONLY)
1479 die(_("Not possible to fast-forward, aborting."));
1480 /* We are going to make a new commit. */
1482 git_committer_info(IDENT_STRICT);
1483 /*
1485 * At this point, we need a real merge. No matter what strategy
1486 * we use, it would operate on the index, possibly affecting the
1487 * working tree, and when resolved cleanly, have the desired
1488 * tree in the index -- this means that the index must be in
1489 * sync with the head commit. The strategies are responsible
1490 * to ensure this.
1491 */
1492 if (use_strategies_nr == 1 ||
1493 /*
1494 * Stash away the local changes so that we can try more than one.
1495 */
1496 save_state(stash))
1497 hashclr(stash);
1498 for (i = 0; i < use_strategies_nr; i++) {
1500 int ret;
1501 if (i) {
1502 printf(_("Rewinding the tree to pristine...\n"));
1503 restore_state(head_commit->object.oid.hash, stash);
1504 }
1505 if (use_strategies_nr != 1)
1506 printf(_("Trying merge strategy %s...\n"),
1507 use_strategies[i]->name);
1508 /*
1509 * Remember which strategy left the state in the working
1510 * tree.
1511 */
1512 wt_strategy = use_strategies[i]->name;
1513 ret = try_merge_strategy(use_strategies[i]->name,
1515 common, remoteheads,
1516 head_commit, head_arg);
1517 if (!option_commit && !ret) {
1518 merge_was_ok = 1;
1519 /*
1520 * This is necessary here just to avoid writing
1521 * the tree, but later we will *not* exit with
1522 * status code 1 because merge_was_ok is set.
1523 */
1524 ret = 1;
1525 }
1526 if (ret) {
1528 /*
1529 * The backend exits with 1 when conflicts are
1530 * left to be resolved, with 2 when it does not
1531 * handle the given merge at all.
1532 */
1533 if (ret == 1) {
1534 int cnt = evaluate_result();
1535 if (best_cnt <= 0 || cnt <= best_cnt) {
1537 best_strategy = use_strategies[i]->name;
1538 best_cnt = cnt;
1539 }
1540 }
1541 if (merge_was_ok)
1542 break;
1543 else
1544 continue;
1545 }
1546 /* Automerge succeeded. */
1548 write_tree_trivial(result_tree);
1549 automerge_was_ok = 1;
1550 break;
1551 }
1552 /*
1554 * If we have a resulting tree, that means the strategy module
1555 * auto resolved the merge cleanly.
1556 */
1557 if (automerge_was_ok) {
1558 ret = finish_automerge(head_commit, head_subsumed,
1559 common, remoteheads,
1560 result_tree, wt_strategy);
1561 goto done;
1562 }
1563 /*
1565 * Pick the result from the best strategy and have the user fix
1566 * it up.
1567 */
1568 if (!best_strategy) {
1569 restore_state(head_commit->object.oid.hash, stash);
1570 if (use_strategies_nr > 1)
1571 fprintf(stderr,
1572 _("No merge strategy handled the merge.\n"));
1573 else
1574 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1575 use_strategies[0]->name);
1576 ret = 2;
1577 goto done;
1578 } else if (best_strategy == wt_strategy)
1579 ; /* We already have its result in the working tree. */
1580 else {
1581 printf(_("Rewinding the tree to pristine...\n"));
1582 restore_state(head_commit->object.oid.hash, stash);
1583 printf(_("Using the %s to prepare resolving by hand.\n"),
1584 best_strategy);
1585 try_merge_strategy(best_strategy, common, remoteheads,
1586 head_commit, head_arg);
1587 }
1588 if (squash)
1590 finish(head_commit, remoteheads, NULL, NULL);
1591 else
1592 write_merge_state(remoteheads);
1593 if (merge_was_ok)
1595 fprintf(stderr, _("Automatic merge went well; "
1596 "stopped before committing as requested\n"));
1597 else
1598 ret = suggest_conflicts();
1599done:
1601 free(branch_to_free);
1602 return ret;
1603}