1/*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
6 * Based on git-merge.sh by Junio C Hamano.
7 */
8
9#include "cache.h"
10#include "parse-options.h"
11#include "builtin.h"
12#include "run-command.h"
13#include "diff.h"
14#include "refs.h"
15#include "commit.h"
16#include "diffcore.h"
17#include "revision.h"
18#include "unpack-trees.h"
19#include "cache-tree.h"
20#include "dir.h"
21#include "utf8.h"
22#include "log-tree.h"
23#include "color.h"
24#include "rerere.h"
25#include "help.h"
26#include "merge-recursive.h"
27#include "resolve-undo.h"
28#include "remote.h"
29#include "fmt-merge-msg.h"
30#include "gpg-interface.h"
31#include "sequencer.h"
32
33#define DEFAULT_TWOHEAD (1<<0)
34#define DEFAULT_OCTOPUS (1<<1)
35#define NO_FAST_FORWARD (1<<2)
36#define NO_TRIVIAL (1<<3)
37
38struct strategy {
39 const char *name;
40 unsigned attr;
41};
42
43static const char * const builtin_merge_usage[] = {
44 N_("git merge [options] [<commit>...]"),
45 N_("git merge [options] <msg> HEAD <commit>"),
46 N_("git merge --abort"),
47 NULL
48};
49
50static int show_diffstat = 1, shortlog_len = -1, squash;
51static int option_commit = 1;
52static int option_edit = -1;
53static int allow_trivial = 1, have_message, verify_signatures;
54static int overwrite_ignore = 1;
55static struct strbuf merge_msg = STRBUF_INIT;
56static struct strategy **use_strategies;
57static size_t use_strategies_nr, use_strategies_alloc;
58static const char **xopts;
59static size_t xopts_nr, xopts_alloc;
60static const char *branch;
61static char *branch_mergeoptions;
62static int option_renormalize;
63static int verbosity;
64static int allow_rerere_auto;
65static int abort_current_merge;
66static int show_progress = -1;
67static int default_to_upstream;
68static const char *sign_commit;
69
70static struct strategy all_strategy[] = {
71 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
72 { "octopus", DEFAULT_OCTOPUS },
73 { "resolve", 0 },
74 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
75 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
76};
77
78static const char *pull_twohead, *pull_octopus;
79
80enum ff_type {
81 FF_NO,
82 FF_ALLOW,
83 FF_ONLY
84};
85
86static enum ff_type fast_forward = FF_ALLOW;
87
88static int option_parse_message(const struct option *opt,
89 const char *arg, int unset)
90{
91 struct strbuf *buf = opt->value;
92
93 if (unset)
94 strbuf_setlen(buf, 0);
95 else if (arg) {
96 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
97 have_message = 1;
98 } else
99 return error(_("switch `m' requires a value"));
100 return 0;
101}
102
103static struct strategy *get_strategy(const char *name)
104{
105 int i;
106 struct strategy *ret;
107 static struct cmdnames main_cmds, other_cmds;
108 static int loaded;
109
110 if (!name)
111 return NULL;
112
113 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
114 if (!strcmp(name, all_strategy[i].name))
115 return &all_strategy[i];
116
117 if (!loaded) {
118 struct cmdnames not_strategies;
119 loaded = 1;
120
121 memset(¬_strategies, 0, sizeof(struct cmdnames));
122 load_command_list("git-merge-", &main_cmds, &other_cmds);
123 for (i = 0; i < main_cmds.cnt; i++) {
124 int j, found = 0;
125 struct cmdname *ent = main_cmds.names[i];
126 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
127 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
128 && !all_strategy[j].name[ent->len])
129 found = 1;
130 if (!found)
131 add_cmdname(¬_strategies, ent->name, ent->len);
132 }
133 exclude_cmds(&main_cmds, ¬_strategies);
134 }
135 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
136 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
137 fprintf(stderr, _("Available strategies are:"));
138 for (i = 0; i < main_cmds.cnt; i++)
139 fprintf(stderr, " %s", main_cmds.names[i]->name);
140 fprintf(stderr, ".\n");
141 if (other_cmds.cnt) {
142 fprintf(stderr, _("Available custom strategies are:"));
143 for (i = 0; i < other_cmds.cnt; i++)
144 fprintf(stderr, " %s", other_cmds.names[i]->name);
145 fprintf(stderr, ".\n");
146 }
147 exit(1);
148 }
149
150 ret = xcalloc(1, sizeof(struct strategy));
151 ret->name = xstrdup(name);
152 ret->attr = NO_TRIVIAL;
153 return ret;
154}
155
156static void append_strategy(struct strategy *s)
157{
158 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
159 use_strategies[use_strategies_nr++] = s;
160}
161
162static int option_parse_strategy(const struct option *opt,
163 const char *name, int unset)
164{
165 if (unset)
166 return 0;
167
168 append_strategy(get_strategy(name));
169 return 0;
170}
171
172static int option_parse_x(const struct option *opt,
173 const char *arg, int unset)
174{
175 if (unset)
176 return 0;
177
178 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
179 xopts[xopts_nr++] = xstrdup(arg);
180 return 0;
181}
182
183static int option_parse_n(const struct option *opt,
184 const char *arg, int unset)
185{
186 show_diffstat = unset;
187 return 0;
188}
189
190static struct option builtin_merge_options[] = {
191 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
192 N_("do not show a diffstat at the end of the merge"),
193 PARSE_OPT_NOARG, option_parse_n },
194 OPT_BOOL(0, "stat", &show_diffstat,
195 N_("show a diffstat at the end of the merge")),
196 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
197 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
198 N_("add (at most <n>) entries from shortlog to merge commit message"),
199 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
200 OPT_BOOL(0, "squash", &squash,
201 N_("create a single commit instead of doing a merge")),
202 OPT_BOOL(0, "commit", &option_commit,
203 N_("perform a commit if the merge succeeds (default)")),
204 OPT_BOOL('e', "edit", &option_edit,
205 N_("edit message before committing")),
206 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
207 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
208 N_("abort if fast-forward is not possible"),
209 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
210 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
211 OPT_BOOL(0, "verify-signatures", &verify_signatures,
212 N_("Verify that the named commit has a valid GPG signature")),
213 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
214 N_("merge strategy to use"), option_parse_strategy),
215 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
216 N_("option for selected merge strategy"), option_parse_x),
217 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
218 N_("merge commit message (for a non-fast-forward merge)"),
219 option_parse_message),
220 OPT__VERBOSITY(&verbosity),
221 OPT_BOOL(0, "abort", &abort_current_merge,
222 N_("abort the current in-progress merge")),
223 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
224 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key id"),
225 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
226 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
227 OPT_END()
228};
229
230/* Cleans up metadata that is uninteresting after a succeeded merge. */
231static void drop_save(void)
232{
233 unlink(git_path("MERGE_HEAD"));
234 unlink(git_path("MERGE_MSG"));
235 unlink(git_path("MERGE_MODE"));
236}
237
238static int save_state(unsigned char *stash)
239{
240 int len;
241 struct child_process cp;
242 struct strbuf buffer = STRBUF_INIT;
243 const char *argv[] = {"stash", "create", NULL};
244
245 memset(&cp, 0, sizeof(cp));
246 cp.argv = argv;
247 cp.out = -1;
248 cp.git_cmd = 1;
249
250 if (start_command(&cp))
251 die(_("could not run stash."));
252 len = strbuf_read(&buffer, cp.out, 1024);
253 close(cp.out);
254
255 if (finish_command(&cp) || len < 0)
256 die(_("stash failed"));
257 else if (!len) /* no changes */
258 return -1;
259 strbuf_setlen(&buffer, buffer.len-1);
260 if (get_sha1(buffer.buf, stash))
261 die(_("not a valid object: %s"), buffer.buf);
262 return 0;
263}
264
265static void read_empty(unsigned const char *sha1, int verbose)
266{
267 int i = 0;
268 const char *args[7];
269
270 args[i++] = "read-tree";
271 if (verbose)
272 args[i++] = "-v";
273 args[i++] = "-m";
274 args[i++] = "-u";
275 args[i++] = EMPTY_TREE_SHA1_HEX;
276 args[i++] = sha1_to_hex(sha1);
277 args[i] = NULL;
278
279 if (run_command_v_opt(args, RUN_GIT_CMD))
280 die(_("read-tree failed"));
281}
282
283static void reset_hard(unsigned const char *sha1, int verbose)
284{
285 int i = 0;
286 const char *args[6];
287
288 args[i++] = "read-tree";
289 if (verbose)
290 args[i++] = "-v";
291 args[i++] = "--reset";
292 args[i++] = "-u";
293 args[i++] = sha1_to_hex(sha1);
294 args[i] = NULL;
295
296 if (run_command_v_opt(args, RUN_GIT_CMD))
297 die(_("read-tree failed"));
298}
299
300static void restore_state(const unsigned char *head,
301 const unsigned char *stash)
302{
303 struct strbuf sb = STRBUF_INIT;
304 const char *args[] = { "stash", "apply", NULL, NULL };
305
306 if (is_null_sha1(stash))
307 return;
308
309 reset_hard(head, 1);
310
311 args[2] = sha1_to_hex(stash);
312
313 /*
314 * It is OK to ignore error here, for example when there was
315 * nothing to restore.
316 */
317 run_command_v_opt(args, RUN_GIT_CMD);
318
319 strbuf_release(&sb);
320 refresh_cache(REFRESH_QUIET);
321}
322
323/* This is called when no merge was necessary. */
324static void finish_up_to_date(const char *msg)
325{
326 if (verbosity >= 0)
327 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
328 drop_save();
329}
330
331static void squash_message(struct commit *commit, struct commit_list *remoteheads)
332{
333 struct rev_info rev;
334 struct strbuf out = STRBUF_INIT;
335 struct commit_list *j;
336 const char *filename;
337 int fd;
338 struct pretty_print_context ctx = {0};
339
340 printf(_("Squash commit -- not updating HEAD\n"));
341 filename = git_path("SQUASH_MSG");
342 fd = open(filename, O_WRONLY | O_CREAT, 0666);
343 if (fd < 0)
344 die_errno(_("Could not write to '%s'"), filename);
345
346 init_revisions(&rev, NULL);
347 rev.ignore_merges = 1;
348 rev.commit_format = CMIT_FMT_MEDIUM;
349
350 commit->object.flags |= UNINTERESTING;
351 add_pending_object(&rev, &commit->object, NULL);
352
353 for (j = remoteheads; j; j = j->next)
354 add_pending_object(&rev, &j->item->object, NULL);
355
356 setup_revisions(0, NULL, &rev, NULL);
357 if (prepare_revision_walk(&rev))
358 die(_("revision walk setup failed"));
359
360 ctx.abbrev = rev.abbrev;
361 ctx.date_mode = rev.date_mode;
362 ctx.fmt = rev.commit_format;
363
364 strbuf_addstr(&out, "Squashed commit of the following:\n");
365 while ((commit = get_revision(&rev)) != NULL) {
366 strbuf_addch(&out, '\n');
367 strbuf_addf(&out, "commit %s\n",
368 sha1_to_hex(commit->object.sha1));
369 pretty_print_commit(&ctx, commit, &out);
370 }
371 if (write(fd, out.buf, out.len) < 0)
372 die_errno(_("Writing SQUASH_MSG"));
373 if (close(fd))
374 die_errno(_("Finishing SQUASH_MSG"));
375 strbuf_release(&out);
376}
377
378static void finish(struct commit *head_commit,
379 struct commit_list *remoteheads,
380 const unsigned char *new_head, const char *msg)
381{
382 struct strbuf reflog_message = STRBUF_INIT;
383 const unsigned char *head = head_commit->object.sha1;
384
385 if (!msg)
386 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
387 else {
388 if (verbosity >= 0)
389 printf("%s\n", msg);
390 strbuf_addf(&reflog_message, "%s: %s",
391 getenv("GIT_REFLOG_ACTION"), msg);
392 }
393 if (squash) {
394 squash_message(head_commit, remoteheads);
395 } else {
396 if (verbosity >= 0 && !merge_msg.len)
397 printf(_("No merge message -- not updating HEAD\n"));
398 else {
399 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
400 update_ref(reflog_message.buf, "HEAD",
401 new_head, head, 0,
402 DIE_ON_ERR);
403 /*
404 * We ignore errors in 'gc --auto', since the
405 * user should see them.
406 */
407 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
408 }
409 }
410 if (new_head && show_diffstat) {
411 struct diff_options opts;
412 diff_setup(&opts);
413 opts.stat_width = -1; /* use full terminal width */
414 opts.stat_graph_width = -1; /* respect statGraphWidth config */
415 opts.output_format |=
416 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
417 opts.detect_rename = DIFF_DETECT_RENAME;
418 diff_setup_done(&opts);
419 diff_tree_sha1(head, new_head, "", &opts);
420 diffcore_std(&opts);
421 diff_flush(&opts);
422 }
423
424 /* Run a post-merge hook */
425 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
426
427 strbuf_release(&reflog_message);
428}
429
430/* Get the name for the merge commit's message. */
431static void merge_name(const char *remote, struct strbuf *msg)
432{
433 struct commit *remote_head;
434 unsigned char branch_head[20];
435 struct strbuf buf = STRBUF_INIT;
436 struct strbuf bname = STRBUF_INIT;
437 const char *ptr;
438 char *found_ref;
439 int len, early;
440
441 strbuf_branchname(&bname, remote);
442 remote = bname.buf;
443
444 memset(branch_head, 0, sizeof(branch_head));
445 remote_head = get_merge_parent(remote);
446 if (!remote_head)
447 die(_("'%s' does not point to a commit"), remote);
448
449 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
450 if (!prefixcmp(found_ref, "refs/heads/")) {
451 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
452 sha1_to_hex(branch_head), remote);
453 goto cleanup;
454 }
455 if (!prefixcmp(found_ref, "refs/tags/")) {
456 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
457 sha1_to_hex(branch_head), remote);
458 goto cleanup;
459 }
460 if (!prefixcmp(found_ref, "refs/remotes/")) {
461 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
462 sha1_to_hex(branch_head), remote);
463 goto cleanup;
464 }
465 }
466
467 /* See if remote matches <name>^^^.. or <name>~<number> */
468 for (len = 0, ptr = remote + strlen(remote);
469 remote < ptr && ptr[-1] == '^';
470 ptr--)
471 len++;
472 if (len)
473 early = 1;
474 else {
475 early = 0;
476 ptr = strrchr(remote, '~');
477 if (ptr) {
478 int seen_nonzero = 0;
479
480 len++; /* count ~ */
481 while (*++ptr && isdigit(*ptr)) {
482 seen_nonzero |= (*ptr != '0');
483 len++;
484 }
485 if (*ptr)
486 len = 0; /* not ...~<number> */
487 else if (seen_nonzero)
488 early = 1;
489 else if (len == 1)
490 early = 1; /* "name~" is "name~1"! */
491 }
492 }
493 if (len) {
494 struct strbuf truname = STRBUF_INIT;
495 strbuf_addstr(&truname, "refs/heads/");
496 strbuf_addstr(&truname, remote);
497 strbuf_setlen(&truname, truname.len - len);
498 if (ref_exists(truname.buf)) {
499 strbuf_addf(msg,
500 "%s\t\tbranch '%s'%s of .\n",
501 sha1_to_hex(remote_head->object.sha1),
502 truname.buf + 11,
503 (early ? " (early part)" : ""));
504 strbuf_release(&truname);
505 goto cleanup;
506 }
507 }
508
509 if (!strcmp(remote, "FETCH_HEAD") &&
510 !access(git_path("FETCH_HEAD"), R_OK)) {
511 const char *filename;
512 FILE *fp;
513 struct strbuf line = STRBUF_INIT;
514 char *ptr;
515
516 filename = git_path("FETCH_HEAD");
517 fp = fopen(filename, "r");
518 if (!fp)
519 die_errno(_("could not open '%s' for reading"),
520 filename);
521 strbuf_getline(&line, fp, '\n');
522 fclose(fp);
523 ptr = strstr(line.buf, "\tnot-for-merge\t");
524 if (ptr)
525 strbuf_remove(&line, ptr-line.buf+1, 13);
526 strbuf_addbuf(msg, &line);
527 strbuf_release(&line);
528 goto cleanup;
529 }
530
531 if (remote_head->util) {
532 struct merge_remote_desc *desc;
533 desc = merge_remote_util(remote_head);
534 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
535 strbuf_addf(msg, "%s\t\t%s '%s'\n",
536 sha1_to_hex(desc->obj->sha1),
537 typename(desc->obj->type),
538 remote);
539 goto cleanup;
540 }
541 }
542
543 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
544 sha1_to_hex(remote_head->object.sha1), remote);
545cleanup:
546 strbuf_release(&buf);
547 strbuf_release(&bname);
548}
549
550static void parse_branch_merge_options(char *bmo)
551{
552 const char **argv;
553 int argc;
554
555 if (!bmo)
556 return;
557 argc = split_cmdline(bmo, &argv);
558 if (argc < 0)
559 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
560 split_cmdline_strerror(argc));
561 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
562 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
563 argc++;
564 argv[0] = "branch.*.mergeoptions";
565 parse_options(argc, argv, NULL, builtin_merge_options,
566 builtin_merge_usage, 0);
567 free(argv);
568}
569
570static int git_merge_config(const char *k, const char *v, void *cb)
571{
572 int status;
573
574 if (branch && !prefixcmp(k, "branch.") &&
575 !prefixcmp(k + 7, branch) &&
576 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
577 free(branch_mergeoptions);
578 branch_mergeoptions = xstrdup(v);
579 return 0;
580 }
581
582 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
583 show_diffstat = git_config_bool(k, v);
584 else if (!strcmp(k, "pull.twohead"))
585 return git_config_string(&pull_twohead, k, v);
586 else if (!strcmp(k, "pull.octopus"))
587 return git_config_string(&pull_octopus, k, v);
588 else if (!strcmp(k, "merge.renormalize"))
589 option_renormalize = git_config_bool(k, v);
590 else if (!strcmp(k, "merge.ff")) {
591 int boolval = git_config_maybe_bool(k, v);
592 if (0 <= boolval) {
593 fast_forward = boolval ? FF_ALLOW : FF_NO;
594 } else if (v && !strcmp(v, "only")) {
595 fast_forward = FF_ONLY;
596 } /* do not barf on values from future versions of git */
597 return 0;
598 } else if (!strcmp(k, "merge.defaulttoupstream")) {
599 default_to_upstream = git_config_bool(k, v);
600 return 0;
601 }
602
603 status = fmt_merge_msg_config(k, v, cb);
604 if (status)
605 return status;
606 status = git_gpg_config(k, v, NULL);
607 if (status)
608 return status;
609 return git_diff_ui_config(k, v, cb);
610}
611
612static int read_tree_trivial(unsigned char *common, unsigned char *head,
613 unsigned char *one)
614{
615 int i, nr_trees = 0;
616 struct tree *trees[MAX_UNPACK_TREES];
617 struct tree_desc t[MAX_UNPACK_TREES];
618 struct unpack_trees_options opts;
619
620 memset(&opts, 0, sizeof(opts));
621 opts.head_idx = 2;
622 opts.src_index = &the_index;
623 opts.dst_index = &the_index;
624 opts.update = 1;
625 opts.verbose_update = 1;
626 opts.trivial_merges_only = 1;
627 opts.merge = 1;
628 trees[nr_trees] = parse_tree_indirect(common);
629 if (!trees[nr_trees++])
630 return -1;
631 trees[nr_trees] = parse_tree_indirect(head);
632 if (!trees[nr_trees++])
633 return -1;
634 trees[nr_trees] = parse_tree_indirect(one);
635 if (!trees[nr_trees++])
636 return -1;
637 opts.fn = threeway_merge;
638 cache_tree_free(&active_cache_tree);
639 for (i = 0; i < nr_trees; i++) {
640 parse_tree(trees[i]);
641 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
642 }
643 if (unpack_trees(nr_trees, t, &opts))
644 return -1;
645 return 0;
646}
647
648static void write_tree_trivial(unsigned char *sha1)
649{
650 if (write_cache_as_tree(sha1, 0, NULL))
651 die(_("git write-tree failed to write a tree"));
652}
653
654static int try_merge_strategy(const char *strategy, struct commit_list *common,
655 struct commit_list *remoteheads,
656 struct commit *head, const char *head_arg)
657{
658 int index_fd;
659 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
660
661 index_fd = hold_locked_index(lock, 1);
662 refresh_cache(REFRESH_QUIET);
663 if (active_cache_changed &&
664 (write_cache(index_fd, active_cache, active_nr) ||
665 commit_locked_index(lock)))
666 return error(_("Unable to write index."));
667 rollback_lock_file(lock);
668
669 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
670 int clean, x;
671 struct commit *result;
672 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
673 int index_fd;
674 struct commit_list *reversed = NULL;
675 struct merge_options o;
676 struct commit_list *j;
677
678 if (remoteheads->next) {
679 error(_("Not handling anything other than two heads merge."));
680 return 2;
681 }
682
683 init_merge_options(&o);
684 if (!strcmp(strategy, "subtree"))
685 o.subtree_shift = "";
686
687 o.renormalize = option_renormalize;
688 o.show_rename_progress =
689 show_progress == -1 ? isatty(2) : show_progress;
690
691 for (x = 0; x < xopts_nr; x++)
692 if (parse_merge_opt(&o, xopts[x]))
693 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
694
695 o.branch1 = head_arg;
696 o.branch2 = merge_remote_util(remoteheads->item)->name;
697
698 for (j = common; j; j = j->next)
699 commit_list_insert(j->item, &reversed);
700
701 index_fd = hold_locked_index(lock, 1);
702 clean = merge_recursive(&o, head,
703 remoteheads->item, reversed, &result);
704 if (active_cache_changed &&
705 (write_cache(index_fd, active_cache, active_nr) ||
706 commit_locked_index(lock)))
707 die (_("unable to write %s"), get_index_file());
708 rollback_lock_file(lock);
709 return clean ? 0 : 1;
710 } else {
711 return try_merge_command(strategy, xopts_nr, xopts,
712 common, head_arg, remoteheads);
713 }
714}
715
716static void count_diff_files(struct diff_queue_struct *q,
717 struct diff_options *opt, void *data)
718{
719 int *count = data;
720
721 (*count) += q->nr;
722}
723
724static int count_unmerged_entries(void)
725{
726 int i, ret = 0;
727
728 for (i = 0; i < active_nr; i++)
729 if (ce_stage(active_cache[i]))
730 ret++;
731
732 return ret;
733}
734
735static void split_merge_strategies(const char *string, struct strategy **list,
736 int *nr, int *alloc)
737{
738 char *p, *q, *buf;
739
740 if (!string)
741 return;
742
743 buf = xstrdup(string);
744 q = buf;
745 for (;;) {
746 p = strchr(q, ' ');
747 if (!p) {
748 ALLOC_GROW(*list, *nr + 1, *alloc);
749 (*list)[(*nr)++].name = xstrdup(q);
750 free(buf);
751 return;
752 } else {
753 *p = '\0';
754 ALLOC_GROW(*list, *nr + 1, *alloc);
755 (*list)[(*nr)++].name = xstrdup(q);
756 q = ++p;
757 }
758 }
759}
760
761static void add_strategies(const char *string, unsigned attr)
762{
763 struct strategy *list = NULL;
764 int list_alloc = 0, list_nr = 0, i;
765
766 memset(&list, 0, sizeof(list));
767 split_merge_strategies(string, &list, &list_nr, &list_alloc);
768 if (list) {
769 for (i = 0; i < list_nr; i++)
770 append_strategy(get_strategy(list[i].name));
771 return;
772 }
773 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
774 if (all_strategy[i].attr & attr)
775 append_strategy(&all_strategy[i]);
776
777}
778
779static void write_merge_msg(struct strbuf *msg)
780{
781 const char *filename = git_path("MERGE_MSG");
782 int fd = open(filename, O_WRONLY | O_CREAT, 0666);
783 if (fd < 0)
784 die_errno(_("Could not open '%s' for writing"),
785 filename);
786 if (write_in_full(fd, msg->buf, msg->len) != msg->len)
787 die_errno(_("Could not write to '%s'"), filename);
788 close(fd);
789}
790
791static void read_merge_msg(struct strbuf *msg)
792{
793 const char *filename = git_path("MERGE_MSG");
794 strbuf_reset(msg);
795 if (strbuf_read_file(msg, filename, 0) < 0)
796 die_errno(_("Could not read from '%s'"), filename);
797}
798
799static void write_merge_state(struct commit_list *);
800static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
801{
802 if (err_msg)
803 error("%s", err_msg);
804 fprintf(stderr,
805 _("Not committing merge; use 'git commit' to complete the merge.\n"));
806 write_merge_state(remoteheads);
807 exit(1);
808}
809
810static const char merge_editor_comment[] =
811N_("Please enter a commit message to explain why this merge is necessary,\n"
812 "especially if it merges an updated upstream into a topic branch.\n"
813 "\n"
814 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
815 "the commit.\n");
816
817static void prepare_to_commit(struct commit_list *remoteheads)
818{
819 struct strbuf msg = STRBUF_INIT;
820 strbuf_addbuf(&msg, &merge_msg);
821 strbuf_addch(&msg, '\n');
822 if (0 < option_edit)
823 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
824 write_merge_msg(&msg);
825 if (run_hook(get_index_file(), "prepare-commit-msg",
826 git_path("MERGE_MSG"), "merge", NULL, NULL))
827 abort_commit(remoteheads, NULL);
828 if (0 < option_edit) {
829 if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
830 abort_commit(remoteheads, NULL);
831 }
832 read_merge_msg(&msg);
833 stripspace(&msg, 0 < option_edit);
834 if (!msg.len)
835 abort_commit(remoteheads, _("Empty commit message."));
836 strbuf_release(&merge_msg);
837 strbuf_addbuf(&merge_msg, &msg);
838 strbuf_release(&msg);
839}
840
841static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
842{
843 unsigned char result_tree[20], result_commit[20];
844 struct commit_list *parent = xmalloc(sizeof(*parent));
845
846 write_tree_trivial(result_tree);
847 printf(_("Wonderful.\n"));
848 parent->item = head;
849 parent->next = xmalloc(sizeof(*parent->next));
850 parent->next->item = remoteheads->item;
851 parent->next->next = NULL;
852 prepare_to_commit(remoteheads);
853 if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL,
854 sign_commit))
855 die(_("failed to write commit object"));
856 finish(head, remoteheads, result_commit, "In-index merge");
857 drop_save();
858 return 0;
859}
860
861static int finish_automerge(struct commit *head,
862 int head_subsumed,
863 struct commit_list *common,
864 struct commit_list *remoteheads,
865 unsigned char *result_tree,
866 const char *wt_strategy)
867{
868 struct commit_list *parents = NULL;
869 struct strbuf buf = STRBUF_INIT;
870 unsigned char result_commit[20];
871
872 free_commit_list(common);
873 parents = remoteheads;
874 if (!head_subsumed || fast_forward == FF_NO)
875 commit_list_insert(head, &parents);
876 strbuf_addch(&merge_msg, '\n');
877 prepare_to_commit(remoteheads);
878 if (commit_tree(&merge_msg, result_tree, parents, result_commit,
879 NULL, sign_commit))
880 die(_("failed to write commit object"));
881 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
882 finish(head, remoteheads, result_commit, buf.buf);
883 strbuf_release(&buf);
884 drop_save();
885 return 0;
886}
887
888static int suggest_conflicts(void)
889{
890 const char *filename;
891 FILE *fp;
892 struct strbuf msgbuf = STRBUF_INIT;
893
894 filename = git_path("MERGE_MSG");
895 fp = fopen(filename, "a");
896 if (!fp)
897 die_errno(_("Could not open '%s' for writing"), filename);
898
899 append_conflicts_hint(&msgbuf);
900 fputs(msgbuf.buf, fp);
901 fclose(fp);
902 rerere(allow_rerere_auto);
903 printf(_("Automatic merge failed; "
904 "fix conflicts and then commit the result.\n"));
905 return 1;
906}
907
908static struct commit *is_old_style_invocation(int argc, const char **argv,
909 const unsigned char *head)
910{
911 struct commit *second_token = NULL;
912 if (argc > 2) {
913 unsigned char second_sha1[20];
914
915 if (get_sha1(argv[1], second_sha1))
916 return NULL;
917 second_token = lookup_commit_reference_gently(second_sha1, 0);
918 if (!second_token)
919 die(_("'%s' is not a commit"), argv[1]);
920 if (hashcmp(second_token->object.sha1, head))
921 return NULL;
922 }
923 return second_token;
924}
925
926static int evaluate_result(void)
927{
928 int cnt = 0;
929 struct rev_info rev;
930
931 /* Check how many files differ. */
932 init_revisions(&rev, "");
933 setup_revisions(0, NULL, &rev, NULL);
934 rev.diffopt.output_format |=
935 DIFF_FORMAT_CALLBACK;
936 rev.diffopt.format_callback = count_diff_files;
937 rev.diffopt.format_callback_data = &cnt;
938 run_diff_files(&rev, 0);
939
940 /*
941 * Check how many unmerged entries are
942 * there.
943 */
944 cnt += count_unmerged_entries();
945
946 return cnt;
947}
948
949/*
950 * Pretend as if the user told us to merge with the remote-tracking
951 * branch we have for the upstream of the current branch
952 */
953static int setup_with_upstream(const char ***argv)
954{
955 struct branch *branch = branch_get(NULL);
956 int i;
957 const char **args;
958
959 if (!branch)
960 die(_("No current branch."));
961 if (!branch->remote)
962 die(_("No remote for the current branch."));
963 if (!branch->merge_nr)
964 die(_("No default upstream defined for the current branch."));
965
966 args = xcalloc(branch->merge_nr + 1, sizeof(char *));
967 for (i = 0; i < branch->merge_nr; i++) {
968 if (!branch->merge[i]->dst)
969 die(_("No remote-tracking branch for %s from %s"),
970 branch->merge[i]->src, branch->remote_name);
971 args[i] = branch->merge[i]->dst;
972 }
973 args[i] = NULL;
974 *argv = args;
975 return i;
976}
977
978static void write_merge_state(struct commit_list *remoteheads)
979{
980 const char *filename;
981 int fd;
982 struct commit_list *j;
983 struct strbuf buf = STRBUF_INIT;
984
985 for (j = remoteheads; j; j = j->next) {
986 unsigned const char *sha1;
987 struct commit *c = j->item;
988 if (c->util && merge_remote_util(c)->obj) {
989 sha1 = merge_remote_util(c)->obj->sha1;
990 } else {
991 sha1 = c->object.sha1;
992 }
993 strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
994 }
995 filename = git_path("MERGE_HEAD");
996 fd = open(filename, O_WRONLY | O_CREAT, 0666);
997 if (fd < 0)
998 die_errno(_("Could not open '%s' for writing"), filename);
999 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1000 die_errno(_("Could not write to '%s'"), filename);
1001 close(fd);
1002 strbuf_addch(&merge_msg, '\n');
1003 write_merge_msg(&merge_msg);
1004
1005 filename = git_path("MERGE_MODE");
1006 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
1007 if (fd < 0)
1008 die_errno(_("Could not open '%s' for writing"), filename);
1009 strbuf_reset(&buf);
1010 if (fast_forward == FF_NO)
1011 strbuf_addf(&buf, "no-ff");
1012 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1013 die_errno(_("Could not write to '%s'"), filename);
1014 close(fd);
1015}
1016
1017static int default_edit_option(void)
1018{
1019 static const char name[] = "GIT_MERGE_AUTOEDIT";
1020 const char *e = getenv(name);
1021 struct stat st_stdin, st_stdout;
1022
1023 if (have_message)
1024 /* an explicit -m msg without --[no-]edit */
1025 return 0;
1026
1027 if (e) {
1028 int v = git_config_maybe_bool(name, e);
1029 if (v < 0)
1030 die("Bad value '%s' in environment '%s'", e, name);
1031 return v;
1032 }
1033
1034 /* Use editor if stdin and stdout are the same and is a tty */
1035 return (!fstat(0, &st_stdin) &&
1036 !fstat(1, &st_stdout) &&
1037 isatty(0) && isatty(1) &&
1038 st_stdin.st_dev == st_stdout.st_dev &&
1039 st_stdin.st_ino == st_stdout.st_ino &&
1040 st_stdin.st_mode == st_stdout.st_mode);
1041}
1042
1043static struct commit_list *collect_parents(struct commit *head_commit,
1044 int *head_subsumed,
1045 int argc, const char **argv)
1046{
1047 int i;
1048 struct commit_list *remoteheads = NULL, *parents, *next;
1049 struct commit_list **remotes = &remoteheads;
1050
1051 if (head_commit)
1052 remotes = &commit_list_insert(head_commit, remotes)->next;
1053 for (i = 0; i < argc; i++) {
1054 struct commit *commit = get_merge_parent(argv[i]);
1055 if (!commit)
1056 help_unknown_ref(argv[i], "merge",
1057 "not something we can merge");
1058 remotes = &commit_list_insert(commit, remotes)->next;
1059 }
1060 *remotes = NULL;
1061
1062 parents = reduce_heads(remoteheads);
1063
1064 *head_subsumed = 1; /* we will flip this to 0 when we find it */
1065 for (remoteheads = NULL, remotes = &remoteheads;
1066 parents;
1067 parents = next) {
1068 struct commit *commit = parents->item;
1069 next = parents->next;
1070 if (commit == head_commit)
1071 *head_subsumed = 0;
1072 else
1073 remotes = &commit_list_insert(commit, remotes)->next;
1074 }
1075 return remoteheads;
1076}
1077
1078int cmd_merge(int argc, const char **argv, const char *prefix)
1079{
1080 unsigned char result_tree[20];
1081 unsigned char stash[20];
1082 unsigned char head_sha1[20];
1083 struct commit *head_commit;
1084 struct strbuf buf = STRBUF_INIT;
1085 const char *head_arg;
1086 int flag, i, ret = 0, head_subsumed;
1087 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1088 struct commit_list *common = NULL;
1089 const char *best_strategy = NULL, *wt_strategy = NULL;
1090 struct commit_list *remoteheads, *p;
1091 void *branch_to_free;
1092
1093 if (argc == 2 && !strcmp(argv[1], "-h"))
1094 usage_with_options(builtin_merge_usage, builtin_merge_options);
1095
1096 /*
1097 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1098 * current branch.
1099 */
1100 branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
1101 if (branch && !prefixcmp(branch, "refs/heads/"))
1102 branch += 11;
1103 if (!branch || is_null_sha1(head_sha1))
1104 head_commit = NULL;
1105 else
1106 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1107
1108 git_config(git_merge_config, NULL);
1109
1110 if (branch_mergeoptions)
1111 parse_branch_merge_options(branch_mergeoptions);
1112 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1113 builtin_merge_usage, 0);
1114 if (shortlog_len < 0)
1115 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1116
1117 if (verbosity < 0 && show_progress == -1)
1118 show_progress = 0;
1119
1120 if (abort_current_merge) {
1121 int nargc = 2;
1122 const char *nargv[] = {"reset", "--merge", NULL};
1123
1124 if (!file_exists(git_path("MERGE_HEAD")))
1125 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1126
1127 /* Invoke 'git reset --merge' */
1128 ret = cmd_reset(nargc, nargv, prefix);
1129 goto done;
1130 }
1131
1132 if (read_cache_unmerged())
1133 die_resolve_conflict("merge");
1134
1135 if (file_exists(git_path("MERGE_HEAD"))) {
1136 /*
1137 * There is no unmerged entry, don't advise 'git
1138 * add/rm <file>', just 'git commit'.
1139 */
1140 if (advice_resolve_conflict)
1141 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1142 "Please, commit your changes before you can merge."));
1143 else
1144 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1145 }
1146 if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
1147 if (advice_resolve_conflict)
1148 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1149 "Please, commit your changes before you can merge."));
1150 else
1151 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1152 }
1153 resolve_undo_clear();
1154
1155 if (verbosity < 0)
1156 show_diffstat = 0;
1157
1158 if (squash) {
1159 if (fast_forward == FF_NO)
1160 die(_("You cannot combine --squash with --no-ff."));
1161 option_commit = 0;
1162 }
1163
1164 if (!abort_current_merge) {
1165 if (!argc) {
1166 if (default_to_upstream)
1167 argc = setup_with_upstream(&argv);
1168 else
1169 die(_("No commit specified and merge.defaultToUpstream not set."));
1170 } else if (argc == 1 && !strcmp(argv[0], "-"))
1171 argv[0] = "@{-1}";
1172 }
1173 if (!argc)
1174 usage_with_options(builtin_merge_usage,
1175 builtin_merge_options);
1176
1177 /*
1178 * This could be traditional "merge <msg> HEAD <commit>..." and
1179 * the way we can tell it is to see if the second token is HEAD,
1180 * but some people might have misused the interface and used a
1181 * commit-ish that is the same as HEAD there instead.
1182 * Traditional format never would have "-m" so it is an
1183 * additional safety measure to check for it.
1184 */
1185
1186 if (!have_message && head_commit &&
1187 is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
1188 strbuf_addstr(&merge_msg, argv[0]);
1189 head_arg = argv[1];
1190 argv += 2;
1191 argc -= 2;
1192 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1193 } else if (!head_commit) {
1194 struct commit *remote_head;
1195 /*
1196 * If the merged head is a valid one there is no reason
1197 * to forbid "git merge" into a branch yet to be born.
1198 * We do the same for "git pull".
1199 */
1200 if (argc != 1)
1201 die(_("Can merge only exactly one commit into "
1202 "empty head"));
1203 if (squash)
1204 die(_("Squash commit into empty head not supported yet"));
1205 if (fast_forward == FF_NO)
1206 die(_("Non-fast-forward commit does not make sense into "
1207 "an empty head"));
1208 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1209 remote_head = remoteheads->item;
1210 if (!remote_head)
1211 die(_("%s - not something we can merge"), argv[0]);
1212 read_empty(remote_head->object.sha1, 0);
1213 update_ref("initial pull", "HEAD", remote_head->object.sha1,
1214 NULL, 0, DIE_ON_ERR);
1215 goto done;
1216 } else {
1217 struct strbuf merge_names = STRBUF_INIT;
1218
1219 /* We are invoked directly as the first-class UI. */
1220 head_arg = "HEAD";
1221
1222 /*
1223 * All the rest are the commits being merged; prepare
1224 * the standard merge summary message to be appended
1225 * to the given message.
1226 */
1227 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1228 for (p = remoteheads; p; p = p->next)
1229 merge_name(merge_remote_util(p->item)->name, &merge_names);
1230
1231 if (!have_message || shortlog_len) {
1232 struct fmt_merge_msg_opts opts;
1233 memset(&opts, 0, sizeof(opts));
1234 opts.add_title = !have_message;
1235 opts.shortlog_len = shortlog_len;
1236 opts.credit_people = (0 < option_edit);
1237
1238 fmt_merge_msg(&merge_names, &merge_msg, &opts);
1239 if (merge_msg.len)
1240 strbuf_setlen(&merge_msg, merge_msg.len - 1);
1241 }
1242 }
1243
1244 if (!head_commit || !argc)
1245 usage_with_options(builtin_merge_usage,
1246 builtin_merge_options);
1247
1248 if (verify_signatures) {
1249 for (p = remoteheads; p; p = p->next) {
1250 struct commit *commit = p->item;
1251 char hex[41];
1252 struct signature_check signature_check;
1253 memset(&signature_check, 0, sizeof(signature_check));
1254
1255 check_commit_signature(commit, &signature_check);
1256
1257 strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
1258 switch (signature_check.result) {
1259 case 'G':
1260 break;
1261 case 'U':
1262 die(_("Commit %s has an untrusted GPG signature, "
1263 "allegedly by %s."), hex, signature_check.signer);
1264 case 'B':
1265 die(_("Commit %s has a bad GPG signature "
1266 "allegedly by %s."), hex, signature_check.signer);
1267 default: /* 'N' */
1268 die(_("Commit %s does not have a GPG signature."), hex);
1269 }
1270 if (verbosity >= 0 && signature_check.result == 'G')
1271 printf(_("Commit %s has a good GPG signature by %s\n"),
1272 hex, signature_check.signer);
1273
1274 free(signature_check.gpg_output);
1275 free(signature_check.gpg_status);
1276 free(signature_check.signer);
1277 free(signature_check.key);
1278 }
1279 }
1280
1281 strbuf_addstr(&buf, "merge");
1282 for (p = remoteheads; p; p = p->next)
1283 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1284 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1285 strbuf_reset(&buf);
1286
1287 for (p = remoteheads; p; p = p->next) {
1288 struct commit *commit = p->item;
1289 strbuf_addf(&buf, "GITHEAD_%s",
1290 sha1_to_hex(commit->object.sha1));
1291 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1292 strbuf_reset(&buf);
1293 if (fast_forward != FF_ONLY &&
1294 merge_remote_util(commit) &&
1295 merge_remote_util(commit)->obj &&
1296 merge_remote_util(commit)->obj->type == OBJ_TAG)
1297 fast_forward = FF_NO;
1298 }
1299
1300 if (option_edit < 0)
1301 option_edit = default_edit_option();
1302
1303 if (!use_strategies) {
1304 if (!remoteheads)
1305 ; /* already up-to-date */
1306 else if (!remoteheads->next)
1307 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1308 else
1309 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1310 }
1311
1312 for (i = 0; i < use_strategies_nr; i++) {
1313 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1314 fast_forward = FF_NO;
1315 if (use_strategies[i]->attr & NO_TRIVIAL)
1316 allow_trivial = 0;
1317 }
1318
1319 if (!remoteheads)
1320 ; /* already up-to-date */
1321 else if (!remoteheads->next)
1322 common = get_merge_bases(head_commit, remoteheads->item, 1);
1323 else {
1324 struct commit_list *list = remoteheads;
1325 commit_list_insert(head_commit, &list);
1326 common = get_octopus_merge_bases(list);
1327 free(list);
1328 }
1329
1330 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
1331 NULL, 0, DIE_ON_ERR);
1332
1333 if (remoteheads && !common)
1334 ; /* No common ancestors found. We need a real merge. */
1335 else if (!remoteheads ||
1336 (!remoteheads->next && !common->next &&
1337 common->item == remoteheads->item)) {
1338 /*
1339 * If head can reach all the merge then we are up to date.
1340 * but first the most common case of merging one remote.
1341 */
1342 finish_up_to_date("Already up-to-date.");
1343 goto done;
1344 } else if (fast_forward != FF_NO && !remoteheads->next &&
1345 !common->next &&
1346 !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
1347 /* Again the most common case of merging one remote. */
1348 struct strbuf msg = STRBUF_INIT;
1349 struct commit *commit;
1350 char hex[41];
1351
1352 strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
1353
1354 if (verbosity >= 0)
1355 printf(_("Updating %s..%s\n"),
1356 hex,
1357 find_unique_abbrev(remoteheads->item->object.sha1,
1358 DEFAULT_ABBREV));
1359 strbuf_addstr(&msg, "Fast-forward");
1360 if (have_message)
1361 strbuf_addstr(&msg,
1362 " (no commit created; -m option ignored)");
1363 commit = remoteheads->item;
1364 if (!commit) {
1365 ret = 1;
1366 goto done;
1367 }
1368
1369 if (checkout_fast_forward(head_commit->object.sha1,
1370 commit->object.sha1,
1371 overwrite_ignore)) {
1372 ret = 1;
1373 goto done;
1374 }
1375
1376 finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
1377 drop_save();
1378 goto done;
1379 } else if (!remoteheads->next && common->next)
1380 ;
1381 /*
1382 * We are not doing octopus and not fast-forward. Need
1383 * a real merge.
1384 */
1385 else if (!remoteheads->next && !common->next && option_commit) {
1386 /*
1387 * We are not doing octopus, not fast-forward, and have
1388 * only one common.
1389 */
1390 refresh_cache(REFRESH_QUIET);
1391 if (allow_trivial && fast_forward != FF_ONLY) {
1392 /* See if it is really trivial. */
1393 git_committer_info(IDENT_STRICT);
1394 printf(_("Trying really trivial in-index merge...\n"));
1395 if (!read_tree_trivial(common->item->object.sha1,
1396 head_commit->object.sha1,
1397 remoteheads->item->object.sha1)) {
1398 ret = merge_trivial(head_commit, remoteheads);
1399 goto done;
1400 }
1401 printf(_("Nope.\n"));
1402 }
1403 } else {
1404 /*
1405 * An octopus. If we can reach all the remote we are up
1406 * to date.
1407 */
1408 int up_to_date = 1;
1409 struct commit_list *j;
1410
1411 for (j = remoteheads; j; j = j->next) {
1412 struct commit_list *common_one;
1413
1414 /*
1415 * Here we *have* to calculate the individual
1416 * merge_bases again, otherwise "git merge HEAD^
1417 * HEAD^^" would be missed.
1418 */
1419 common_one = get_merge_bases(head_commit, j->item, 1);
1420 if (hashcmp(common_one->item->object.sha1,
1421 j->item->object.sha1)) {
1422 up_to_date = 0;
1423 break;
1424 }
1425 }
1426 if (up_to_date) {
1427 finish_up_to_date("Already up-to-date. Yeeah!");
1428 goto done;
1429 }
1430 }
1431
1432 if (fast_forward == FF_ONLY)
1433 die(_("Not possible to fast-forward, aborting."));
1434
1435 /* We are going to make a new commit. */
1436 git_committer_info(IDENT_STRICT);
1437
1438 /*
1439 * At this point, we need a real merge. No matter what strategy
1440 * we use, it would operate on the index, possibly affecting the
1441 * working tree, and when resolved cleanly, have the desired
1442 * tree in the index -- this means that the index must be in
1443 * sync with the head commit. The strategies are responsible
1444 * to ensure this.
1445 */
1446 if (use_strategies_nr == 1 ||
1447 /*
1448 * Stash away the local changes so that we can try more than one.
1449 */
1450 save_state(stash))
1451 hashcpy(stash, null_sha1);
1452
1453 for (i = 0; i < use_strategies_nr; i++) {
1454 int ret;
1455 if (i) {
1456 printf(_("Rewinding the tree to pristine...\n"));
1457 restore_state(head_commit->object.sha1, stash);
1458 }
1459 if (use_strategies_nr != 1)
1460 printf(_("Trying merge strategy %s...\n"),
1461 use_strategies[i]->name);
1462 /*
1463 * Remember which strategy left the state in the working
1464 * tree.
1465 */
1466 wt_strategy = use_strategies[i]->name;
1467
1468 ret = try_merge_strategy(use_strategies[i]->name,
1469 common, remoteheads,
1470 head_commit, head_arg);
1471 if (!option_commit && !ret) {
1472 merge_was_ok = 1;
1473 /*
1474 * This is necessary here just to avoid writing
1475 * the tree, but later we will *not* exit with
1476 * status code 1 because merge_was_ok is set.
1477 */
1478 ret = 1;
1479 }
1480
1481 if (ret) {
1482 /*
1483 * The backend exits with 1 when conflicts are
1484 * left to be resolved, with 2 when it does not
1485 * handle the given merge at all.
1486 */
1487 if (ret == 1) {
1488 int cnt = evaluate_result();
1489
1490 if (best_cnt <= 0 || cnt <= best_cnt) {
1491 best_strategy = use_strategies[i]->name;
1492 best_cnt = cnt;
1493 }
1494 }
1495 if (merge_was_ok)
1496 break;
1497 else
1498 continue;
1499 }
1500
1501 /* Automerge succeeded. */
1502 write_tree_trivial(result_tree);
1503 automerge_was_ok = 1;
1504 break;
1505 }
1506
1507 /*
1508 * If we have a resulting tree, that means the strategy module
1509 * auto resolved the merge cleanly.
1510 */
1511 if (automerge_was_ok) {
1512 ret = finish_automerge(head_commit, head_subsumed,
1513 common, remoteheads,
1514 result_tree, wt_strategy);
1515 goto done;
1516 }
1517
1518 /*
1519 * Pick the result from the best strategy and have the user fix
1520 * it up.
1521 */
1522 if (!best_strategy) {
1523 restore_state(head_commit->object.sha1, stash);
1524 if (use_strategies_nr > 1)
1525 fprintf(stderr,
1526 _("No merge strategy handled the merge.\n"));
1527 else
1528 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1529 use_strategies[0]->name);
1530 ret = 2;
1531 goto done;
1532 } else if (best_strategy == wt_strategy)
1533 ; /* We already have its result in the working tree. */
1534 else {
1535 printf(_("Rewinding the tree to pristine...\n"));
1536 restore_state(head_commit->object.sha1, stash);
1537 printf(_("Using the %s to prepare resolving by hand.\n"),
1538 best_strategy);
1539 try_merge_strategy(best_strategy, common, remoteheads,
1540 head_commit, head_arg);
1541 }
1542
1543 if (squash)
1544 finish(head_commit, remoteheads, NULL, NULL);
1545 else
1546 write_merge_state(remoteheads);
1547
1548 if (merge_was_ok)
1549 fprintf(stderr, _("Automatic merge went well; "
1550 "stopped before committing as requested\n"));
1551 else
1552 ret = suggest_conflicts();
1553
1554done:
1555 free(branch_to_free);
1556 return ret;
1557}