lockfile.h: extract new header file for the functions in lockfile.c
[git/git.git] / builtin / merge.c
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 "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
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
38 struct strategy {
39 const char *name;
40 unsigned attr;
41 };
42
43 static 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
50 static int show_diffstat = 1, shortlog_len = -1, squash;
51 static int option_commit = 1;
52 static int option_edit = -1;
53 static int allow_trivial = 1, have_message, verify_signatures;
54 static int overwrite_ignore = 1;
55 static struct strbuf merge_msg = STRBUF_INIT;
56 static struct strategy **use_strategies;
57 static size_t use_strategies_nr, use_strategies_alloc;
58 static const char **xopts;
59 static size_t xopts_nr, xopts_alloc;
60 static const char *branch;
61 static char *branch_mergeoptions;
62 static int option_renormalize;
63 static int verbosity;
64 static int allow_rerere_auto;
65 static int abort_current_merge;
66 static int show_progress = -1;
67 static int default_to_upstream = 1;
68 static const char *sign_commit;
69
70 static 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
78 static const char *pull_twohead, *pull_octopus;
79
80 enum ff_type {
81 FF_NO,
82 FF_ALLOW,
83 FF_ONLY
84 };
85
86 static enum ff_type fast_forward = FF_ALLOW;
87
88 static 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
103 static 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(&not_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(&not_strategies, ent->name, ent->len);
132 }
133 exclude_cmds(&main_cmds, &not_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
156 static 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
162 static 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
172 static 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
183 static int option_parse_n(const struct option *opt,
184 const char *arg, int unset)
185 {
186 show_diffstat = unset;
187 return 0;
188 }
189
190 static 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. */
231 static 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
238 static int save_state(unsigned char *stash)
239 {
240 int len;
241 struct child_process cp = CHILD_PROCESS_INIT;
242 struct strbuf buffer = STRBUF_INIT;
243 const char *argv[] = {"stash", "create", NULL};
244
245 cp.argv = argv;
246 cp.out = -1;
247 cp.git_cmd = 1;
248
249 if (start_command(&cp))
250 die(_("could not run stash."));
251 len = strbuf_read(&buffer, cp.out, 1024);
252 close(cp.out);
253
254 if (finish_command(&cp) || len < 0)
255 die(_("stash failed"));
256 else if (!len) /* no changes */
257 return -1;
258 strbuf_setlen(&buffer, buffer.len-1);
259 if (get_sha1(buffer.buf, stash))
260 die(_("not a valid object: %s"), buffer.buf);
261 return 0;
262 }
263
264 static void read_empty(unsigned const char *sha1, int verbose)
265 {
266 int i = 0;
267 const char *args[7];
268
269 args[i++] = "read-tree";
270 if (verbose)
271 args[i++] = "-v";
272 args[i++] = "-m";
273 args[i++] = "-u";
274 args[i++] = EMPTY_TREE_SHA1_HEX;
275 args[i++] = sha1_to_hex(sha1);
276 args[i] = NULL;
277
278 if (run_command_v_opt(args, RUN_GIT_CMD))
279 die(_("read-tree failed"));
280 }
281
282 static void reset_hard(unsigned const char *sha1, int verbose)
283 {
284 int i = 0;
285 const char *args[6];
286
287 args[i++] = "read-tree";
288 if (verbose)
289 args[i++] = "-v";
290 args[i++] = "--reset";
291 args[i++] = "-u";
292 args[i++] = sha1_to_hex(sha1);
293 args[i] = NULL;
294
295 if (run_command_v_opt(args, RUN_GIT_CMD))
296 die(_("read-tree failed"));
297 }
298
299 static void restore_state(const unsigned char *head,
300 const unsigned char *stash)
301 {
302 struct strbuf sb = STRBUF_INIT;
303 const char *args[] = { "stash", "apply", NULL, NULL };
304
305 if (is_null_sha1(stash))
306 return;
307
308 reset_hard(head, 1);
309
310 args[2] = sha1_to_hex(stash);
311
312 /*
313 * It is OK to ignore error here, for example when there was
314 * nothing to restore.
315 */
316 run_command_v_opt(args, RUN_GIT_CMD);
317
318 strbuf_release(&sb);
319 refresh_cache(REFRESH_QUIET);
320 }
321
322 /* This is called when no merge was necessary. */
323 static void finish_up_to_date(const char *msg)
324 {
325 if (verbosity >= 0)
326 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
327 drop_save();
328 }
329
330 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
331 {
332 struct rev_info rev;
333 struct strbuf out = STRBUF_INIT;
334 struct commit_list *j;
335 const char *filename;
336 int fd;
337 struct pretty_print_context ctx = {0};
338
339 printf(_("Squash commit -- not updating HEAD\n"));
340 filename = git_path("SQUASH_MSG");
341 fd = open(filename, O_WRONLY | O_CREAT, 0666);
342 if (fd < 0)
343 die_errno(_("Could not write to '%s'"), filename);
344
345 init_revisions(&rev, NULL);
346 rev.ignore_merges = 1;
347 rev.commit_format = CMIT_FMT_MEDIUM;
348
349 commit->object.flags |= UNINTERESTING;
350 add_pending_object(&rev, &commit->object, NULL);
351
352 for (j = remoteheads; j; j = j->next)
353 add_pending_object(&rev, &j->item->object, NULL);
354
355 setup_revisions(0, NULL, &rev, NULL);
356 if (prepare_revision_walk(&rev))
357 die(_("revision walk setup failed"));
358
359 ctx.abbrev = rev.abbrev;
360 ctx.date_mode = rev.date_mode;
361 ctx.fmt = rev.commit_format;
362
363 strbuf_addstr(&out, "Squashed commit of the following:\n");
364 while ((commit = get_revision(&rev)) != NULL) {
365 strbuf_addch(&out, '\n');
366 strbuf_addf(&out, "commit %s\n",
367 sha1_to_hex(commit->object.sha1));
368 pretty_print_commit(&ctx, commit, &out);
369 }
370 if (write_in_full(fd, out.buf, out.len) != out.len)
371 die_errno(_("Writing SQUASH_MSG"));
372 if (close(fd))
373 die_errno(_("Finishing SQUASH_MSG"));
374 strbuf_release(&out);
375 }
376
377 static void finish(struct commit *head_commit,
378 struct commit_list *remoteheads,
379 const unsigned char *new_head, const char *msg)
380 {
381 struct strbuf reflog_message = STRBUF_INIT;
382 const unsigned char *head = head_commit->object.sha1;
383
384 if (!msg)
385 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
386 else {
387 if (verbosity >= 0)
388 printf("%s\n", msg);
389 strbuf_addf(&reflog_message, "%s: %s",
390 getenv("GIT_REFLOG_ACTION"), msg);
391 }
392 if (squash) {
393 squash_message(head_commit, remoteheads);
394 } else {
395 if (verbosity >= 0 && !merge_msg.len)
396 printf(_("No merge message -- not updating HEAD\n"));
397 else {
398 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
399 update_ref(reflog_message.buf, "HEAD",
400 new_head, head, 0,
401 UPDATE_REFS_DIE_ON_ERR);
402 /*
403 * We ignore errors in 'gc --auto', since the
404 * user should see them.
405 */
406 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
407 }
408 }
409 if (new_head && show_diffstat) {
410 struct diff_options opts;
411 diff_setup(&opts);
412 opts.stat_width = -1; /* use full terminal width */
413 opts.stat_graph_width = -1; /* respect statGraphWidth config */
414 opts.output_format |=
415 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
416 opts.detect_rename = DIFF_DETECT_RENAME;
417 diff_setup_done(&opts);
418 diff_tree_sha1(head, new_head, "", &opts);
419 diffcore_std(&opts);
420 diff_flush(&opts);
421 }
422
423 /* Run a post-merge hook */
424 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
425
426 strbuf_release(&reflog_message);
427 }
428
429 /* Get the name for the merge commit's message. */
430 static void merge_name(const char *remote, struct strbuf *msg)
431 {
432 struct commit *remote_head;
433 unsigned char branch_head[20];
434 struct strbuf buf = STRBUF_INIT;
435 struct strbuf bname = STRBUF_INIT;
436 const char *ptr;
437 char *found_ref;
438 int len, early;
439
440 strbuf_branchname(&bname, remote);
441 remote = bname.buf;
442
443 memset(branch_head, 0, sizeof(branch_head));
444 remote_head = get_merge_parent(remote);
445 if (!remote_head)
446 die(_("'%s' does not point to a commit"), remote);
447
448 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
449 if (starts_with(found_ref, "refs/heads/")) {
450 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
451 sha1_to_hex(branch_head), remote);
452 goto cleanup;
453 }
454 if (starts_with(found_ref, "refs/tags/")) {
455 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
456 sha1_to_hex(branch_head), remote);
457 goto cleanup;
458 }
459 if (starts_with(found_ref, "refs/remotes/")) {
460 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
461 sha1_to_hex(branch_head), remote);
462 goto cleanup;
463 }
464 }
465
466 /* See if remote matches <name>^^^.. or <name>~<number> */
467 for (len = 0, ptr = remote + strlen(remote);
468 remote < ptr && ptr[-1] == '^';
469 ptr--)
470 len++;
471 if (len)
472 early = 1;
473 else {
474 early = 0;
475 ptr = strrchr(remote, '~');
476 if (ptr) {
477 int seen_nonzero = 0;
478
479 len++; /* count ~ */
480 while (*++ptr && isdigit(*ptr)) {
481 seen_nonzero |= (*ptr != '0');
482 len++;
483 }
484 if (*ptr)
485 len = 0; /* not ...~<number> */
486 else if (seen_nonzero)
487 early = 1;
488 else if (len == 1)
489 early = 1; /* "name~" is "name~1"! */
490 }
491 }
492 if (len) {
493 struct strbuf truname = STRBUF_INIT;
494 strbuf_addstr(&truname, "refs/heads/");
495 strbuf_addstr(&truname, remote);
496 strbuf_setlen(&truname, truname.len - len);
497 if (ref_exists(truname.buf)) {
498 strbuf_addf(msg,
499 "%s\t\tbranch '%s'%s of .\n",
500 sha1_to_hex(remote_head->object.sha1),
501 truname.buf + 11,
502 (early ? " (early part)" : ""));
503 strbuf_release(&truname);
504 goto cleanup;
505 }
506 }
507
508 if (!strcmp(remote, "FETCH_HEAD") &&
509 !access(git_path("FETCH_HEAD"), R_OK)) {
510 const char *filename;
511 FILE *fp;
512 struct strbuf line = STRBUF_INIT;
513 char *ptr;
514
515 filename = git_path("FETCH_HEAD");
516 fp = fopen(filename, "r");
517 if (!fp)
518 die_errno(_("could not open '%s' for reading"),
519 filename);
520 strbuf_getline(&line, fp, '\n');
521 fclose(fp);
522 ptr = strstr(line.buf, "\tnot-for-merge\t");
523 if (ptr)
524 strbuf_remove(&line, ptr-line.buf+1, 13);
525 strbuf_addbuf(msg, &line);
526 strbuf_release(&line);
527 goto cleanup;
528 }
529
530 if (remote_head->util) {
531 struct merge_remote_desc *desc;
532 desc = merge_remote_util(remote_head);
533 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
534 strbuf_addf(msg, "%s\t\t%s '%s'\n",
535 sha1_to_hex(desc->obj->sha1),
536 typename(desc->obj->type),
537 remote);
538 goto cleanup;
539 }
540 }
541
542 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
543 sha1_to_hex(remote_head->object.sha1), remote);
544 cleanup:
545 strbuf_release(&buf);
546 strbuf_release(&bname);
547 }
548
549 static void parse_branch_merge_options(char *bmo)
550 {
551 const char **argv;
552 int argc;
553
554 if (!bmo)
555 return;
556 argc = split_cmdline(bmo, &argv);
557 if (argc < 0)
558 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
559 split_cmdline_strerror(argc));
560 REALLOC_ARRAY(argv, argc + 2);
561 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
562 argc++;
563 argv[0] = "branch.*.mergeoptions";
564 parse_options(argc, argv, NULL, builtin_merge_options,
565 builtin_merge_usage, 0);
566 free(argv);
567 }
568
569 static int git_merge_config(const char *k, const char *v, void *cb)
570 {
571 int status;
572
573 if (branch && starts_with(k, "branch.") &&
574 starts_with(k + 7, branch) &&
575 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
576 free(branch_mergeoptions);
577 branch_mergeoptions = xstrdup(v);
578 return 0;
579 }
580
581 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
582 show_diffstat = git_config_bool(k, v);
583 else if (!strcmp(k, "pull.twohead"))
584 return git_config_string(&pull_twohead, k, v);
585 else if (!strcmp(k, "pull.octopus"))
586 return git_config_string(&pull_octopus, k, v);
587 else if (!strcmp(k, "merge.renormalize"))
588 option_renormalize = git_config_bool(k, v);
589 else if (!strcmp(k, "merge.ff")) {
590 int boolval = git_config_maybe_bool(k, v);
591 if (0 <= boolval) {
592 fast_forward = boolval ? FF_ALLOW : FF_NO;
593 } else if (v && !strcmp(v, "only")) {
594 fast_forward = FF_ONLY;
595 } /* do not barf on values from future versions of git */
596 return 0;
597 } else if (!strcmp(k, "merge.defaulttoupstream")) {
598 default_to_upstream = git_config_bool(k, v);
599 return 0;
600 } else if (!strcmp(k, "commit.gpgsign")) {
601 sign_commit = git_config_bool(k, v) ? "" : NULL;
602 return 0;
603 }
604
605 status = fmt_merge_msg_config(k, v, cb);
606 if (status)
607 return status;
608 status = git_gpg_config(k, v, NULL);
609 if (status)
610 return status;
611 return git_diff_ui_config(k, v, cb);
612 }
613
614 static int read_tree_trivial(unsigned char *common, unsigned char *head,
615 unsigned char *one)
616 {
617 int i, nr_trees = 0;
618 struct tree *trees[MAX_UNPACK_TREES];
619 struct tree_desc t[MAX_UNPACK_TREES];
620 struct unpack_trees_options opts;
621
622 memset(&opts, 0, sizeof(opts));
623 opts.head_idx = 2;
624 opts.src_index = &the_index;
625 opts.dst_index = &the_index;
626 opts.update = 1;
627 opts.verbose_update = 1;
628 opts.trivial_merges_only = 1;
629 opts.merge = 1;
630 trees[nr_trees] = parse_tree_indirect(common);
631 if (!trees[nr_trees++])
632 return -1;
633 trees[nr_trees] = parse_tree_indirect(head);
634 if (!trees[nr_trees++])
635 return -1;
636 trees[nr_trees] = parse_tree_indirect(one);
637 if (!trees[nr_trees++])
638 return -1;
639 opts.fn = threeway_merge;
640 cache_tree_free(&active_cache_tree);
641 for (i = 0; i < nr_trees; i++) {
642 parse_tree(trees[i]);
643 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
644 }
645 if (unpack_trees(nr_trees, t, &opts))
646 return -1;
647 return 0;
648 }
649
650 static void write_tree_trivial(unsigned char *sha1)
651 {
652 if (write_cache_as_tree(sha1, 0, NULL))
653 die(_("git write-tree failed to write a tree"));
654 }
655
656 static int try_merge_strategy(const char *strategy, struct commit_list *common,
657 struct commit_list *remoteheads,
658 struct commit *head, const char *head_arg)
659 {
660 static struct lock_file lock;
661
662 hold_locked_index(&lock, 1);
663 refresh_cache(REFRESH_QUIET);
664 if (active_cache_changed &&
665 write_locked_index(&the_index, &lock, COMMIT_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 commit_list *reversed = NULL;
673 struct merge_options o;
674 struct commit_list *j;
675
676 if (remoteheads->next) {
677 error(_("Not handling anything other than two heads merge."));
678 return 2;
679 }
680
681 init_merge_options(&o);
682 if (!strcmp(strategy, "subtree"))
683 o.subtree_shift = "";
684
685 o.renormalize = option_renormalize;
686 o.show_rename_progress =
687 show_progress == -1 ? isatty(2) : show_progress;
688
689 for (x = 0; x < xopts_nr; x++)
690 if (parse_merge_opt(&o, xopts[x]))
691 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
692
693 o.branch1 = head_arg;
694 o.branch2 = merge_remote_util(remoteheads->item)->name;
695
696 for (j = common; j; j = j->next)
697 commit_list_insert(j->item, &reversed);
698
699 hold_locked_index(&lock, 1);
700 clean = merge_recursive(&o, head,
701 remoteheads->item, reversed, &result);
702 if (active_cache_changed &&
703 write_locked_index(&the_index, &lock, COMMIT_LOCK))
704 die (_("unable to write %s"), get_index_file());
705 rollback_lock_file(&lock);
706 return clean ? 0 : 1;
707 } else {
708 return try_merge_command(strategy, xopts_nr, xopts,
709 common, head_arg, remoteheads);
710 }
711 }
712
713 static void count_diff_files(struct diff_queue_struct *q,
714 struct diff_options *opt, void *data)
715 {
716 int *count = data;
717
718 (*count) += q->nr;
719 }
720
721 static int count_unmerged_entries(void)
722 {
723 int i, ret = 0;
724
725 for (i = 0; i < active_nr; i++)
726 if (ce_stage(active_cache[i]))
727 ret++;
728
729 return ret;
730 }
731
732 static void split_merge_strategies(const char *string, struct strategy **list,
733 int *nr, int *alloc)
734 {
735 char *p, *q, *buf;
736
737 if (!string)
738 return;
739
740 buf = xstrdup(string);
741 q = buf;
742 for (;;) {
743 p = strchr(q, ' ');
744 if (!p) {
745 ALLOC_GROW(*list, *nr + 1, *alloc);
746 (*list)[(*nr)++].name = xstrdup(q);
747 free(buf);
748 return;
749 } else {
750 *p = '\0';
751 ALLOC_GROW(*list, *nr + 1, *alloc);
752 (*list)[(*nr)++].name = xstrdup(q);
753 q = ++p;
754 }
755 }
756 }
757
758 static void add_strategies(const char *string, unsigned attr)
759 {
760 struct strategy *list = NULL;
761 int list_alloc = 0, list_nr = 0, i;
762
763 memset(&list, 0, sizeof(list));
764 split_merge_strategies(string, &list, &list_nr, &list_alloc);
765 if (list) {
766 for (i = 0; i < list_nr; i++)
767 append_strategy(get_strategy(list[i].name));
768 return;
769 }
770 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
771 if (all_strategy[i].attr & attr)
772 append_strategy(&all_strategy[i]);
773
774 }
775
776 static void write_merge_msg(struct strbuf *msg)
777 {
778 const char *filename = git_path("MERGE_MSG");
779 int fd = open(filename, O_WRONLY | O_CREAT, 0666);
780 if (fd < 0)
781 die_errno(_("Could not open '%s' for writing"),
782 filename);
783 if (write_in_full(fd, msg->buf, msg->len) != msg->len)
784 die_errno(_("Could not write to '%s'"), filename);
785 close(fd);
786 }
787
788 static void read_merge_msg(struct strbuf *msg)
789 {
790 const char *filename = git_path("MERGE_MSG");
791 strbuf_reset(msg);
792 if (strbuf_read_file(msg, filename, 0) < 0)
793 die_errno(_("Could not read from '%s'"), filename);
794 }
795
796 static void write_merge_state(struct commit_list *);
797 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
798 {
799 if (err_msg)
800 error("%s", err_msg);
801 fprintf(stderr,
802 _("Not committing merge; use 'git commit' to complete the merge.\n"));
803 write_merge_state(remoteheads);
804 exit(1);
805 }
806
807 static const char merge_editor_comment[] =
808 N_("Please enter a commit message to explain why this merge is necessary,\n"
809 "especially if it merges an updated upstream into a topic branch.\n"
810 "\n"
811 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
812 "the commit.\n");
813
814 static void prepare_to_commit(struct commit_list *remoteheads)
815 {
816 struct strbuf msg = STRBUF_INIT;
817 strbuf_addbuf(&msg, &merge_msg);
818 strbuf_addch(&msg, '\n');
819 if (0 < option_edit)
820 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
821 write_merge_msg(&msg);
822 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
823 git_path("MERGE_MSG"), "merge", NULL))
824 abort_commit(remoteheads, NULL);
825 if (0 < option_edit) {
826 if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
827 abort_commit(remoteheads, NULL);
828 }
829 read_merge_msg(&msg);
830 stripspace(&msg, 0 < option_edit);
831 if (!msg.len)
832 abort_commit(remoteheads, _("Empty commit message."));
833 strbuf_release(&merge_msg);
834 strbuf_addbuf(&merge_msg, &msg);
835 strbuf_release(&msg);
836 }
837
838 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
839 {
840 unsigned char result_tree[20], result_commit[20];
841 struct commit_list *parents, **pptr = &parents;
842
843 write_tree_trivial(result_tree);
844 printf(_("Wonderful.\n"));
845 pptr = commit_list_append(head, pptr);
846 pptr = commit_list_append(remoteheads->item, pptr);
847 prepare_to_commit(remoteheads);
848 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
849 result_commit, NULL, sign_commit))
850 die(_("failed to write commit object"));
851 finish(head, remoteheads, result_commit, "In-index merge");
852 drop_save();
853 return 0;
854 }
855
856 static int finish_automerge(struct commit *head,
857 int head_subsumed,
858 struct commit_list *common,
859 struct commit_list *remoteheads,
860 unsigned char *result_tree,
861 const char *wt_strategy)
862 {
863 struct commit_list *parents = NULL;
864 struct strbuf buf = STRBUF_INIT;
865 unsigned char result_commit[20];
866
867 free_commit_list(common);
868 parents = remoteheads;
869 if (!head_subsumed || fast_forward == FF_NO)
870 commit_list_insert(head, &parents);
871 strbuf_addch(&merge_msg, '\n');
872 prepare_to_commit(remoteheads);
873 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
874 result_commit, NULL, sign_commit))
875 die(_("failed to write commit object"));
876 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
877 finish(head, remoteheads, result_commit, buf.buf);
878 strbuf_release(&buf);
879 drop_save();
880 return 0;
881 }
882
883 static int suggest_conflicts(int renormalizing)
884 {
885 const char *filename;
886 FILE *fp;
887 int pos;
888
889 filename = git_path("MERGE_MSG");
890 fp = fopen(filename, "a");
891 if (!fp)
892 die_errno(_("Could not open '%s' for writing"), filename);
893 fprintf(fp, "\nConflicts:\n");
894 for (pos = 0; pos < active_nr; pos++) {
895 const struct cache_entry *ce = active_cache[pos];
896
897 if (ce_stage(ce)) {
898 fprintf(fp, "\t%s\n", ce->name);
899 while (pos + 1 < active_nr &&
900 !strcmp(ce->name,
901 active_cache[pos + 1]->name))
902 pos++;
903 }
904 }
905 fclose(fp);
906 rerere(allow_rerere_auto);
907 printf(_("Automatic merge failed; "
908 "fix conflicts and then commit the result.\n"));
909 return 1;
910 }
911
912 static struct commit *is_old_style_invocation(int argc, const char **argv,
913 const unsigned char *head)
914 {
915 struct commit *second_token = NULL;
916 if (argc > 2) {
917 unsigned char second_sha1[20];
918
919 if (get_sha1(argv[1], second_sha1))
920 return NULL;
921 second_token = lookup_commit_reference_gently(second_sha1, 0);
922 if (!second_token)
923 die(_("'%s' is not a commit"), argv[1]);
924 if (hashcmp(second_token->object.sha1, head))
925 return NULL;
926 }
927 return second_token;
928 }
929
930 static int evaluate_result(void)
931 {
932 int cnt = 0;
933 struct rev_info rev;
934
935 /* Check how many files differ. */
936 init_revisions(&rev, "");
937 setup_revisions(0, NULL, &rev, NULL);
938 rev.diffopt.output_format |=
939 DIFF_FORMAT_CALLBACK;
940 rev.diffopt.format_callback = count_diff_files;
941 rev.diffopt.format_callback_data = &cnt;
942 run_diff_files(&rev, 0);
943
944 /*
945 * Check how many unmerged entries are
946 * there.
947 */
948 cnt += count_unmerged_entries();
949
950 return cnt;
951 }
952
953 /*
954 * Pretend as if the user told us to merge with the remote-tracking
955 * branch we have for the upstream of the current branch
956 */
957 static int setup_with_upstream(const char ***argv)
958 {
959 struct branch *branch = branch_get(NULL);
960 int i;
961 const char **args;
962
963 if (!branch)
964 die(_("No current branch."));
965 if (!branch->remote)
966 die(_("No remote for the current branch."));
967 if (!branch->merge_nr)
968 die(_("No default upstream defined for the current branch."));
969
970 args = xcalloc(branch->merge_nr + 1, sizeof(char *));
971 for (i = 0; i < branch->merge_nr; i++) {
972 if (!branch->merge[i]->dst)
973 die(_("No remote-tracking branch for %s from %s"),
974 branch->merge[i]->src, branch->remote_name);
975 args[i] = branch->merge[i]->dst;
976 }
977 args[i] = NULL;
978 *argv = args;
979 return i;
980 }
981
982 static void write_merge_state(struct commit_list *remoteheads)
983 {
984 const char *filename;
985 int fd;
986 struct commit_list *j;
987 struct strbuf buf = STRBUF_INIT;
988
989 for (j = remoteheads; j; j = j->next) {
990 unsigned const char *sha1;
991 struct commit *c = j->item;
992 if (c->util && merge_remote_util(c)->obj) {
993 sha1 = merge_remote_util(c)->obj->sha1;
994 } else {
995 sha1 = c->object.sha1;
996 }
997 strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
998 }
999 filename = git_path("MERGE_HEAD");
1000 fd = open(filename, O_WRONLY | O_CREAT, 0666);
1001 if (fd < 0)
1002 die_errno(_("Could not open '%s' for writing"), filename);
1003 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1004 die_errno(_("Could not write to '%s'"), filename);
1005 close(fd);
1006 strbuf_addch(&merge_msg, '\n');
1007 write_merge_msg(&merge_msg);
1008
1009 filename = git_path("MERGE_MODE");
1010 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
1011 if (fd < 0)
1012 die_errno(_("Could not open '%s' for writing"), filename);
1013 strbuf_reset(&buf);
1014 if (fast_forward == FF_NO)
1015 strbuf_addf(&buf, "no-ff");
1016 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1017 die_errno(_("Could not write to '%s'"), filename);
1018 close(fd);
1019 }
1020
1021 static int default_edit_option(void)
1022 {
1023 static const char name[] = "GIT_MERGE_AUTOEDIT";
1024 const char *e = getenv(name);
1025 struct stat st_stdin, st_stdout;
1026
1027 if (have_message)
1028 /* an explicit -m msg without --[no-]edit */
1029 return 0;
1030
1031 if (e) {
1032 int v = git_config_maybe_bool(name, e);
1033 if (v < 0)
1034 die("Bad value '%s' in environment '%s'", e, name);
1035 return v;
1036 }
1037
1038 /* Use editor if stdin and stdout are the same and is a tty */
1039 return (!fstat(0, &st_stdin) &&
1040 !fstat(1, &st_stdout) &&
1041 isatty(0) && isatty(1) &&
1042 st_stdin.st_dev == st_stdout.st_dev &&
1043 st_stdin.st_ino == st_stdout.st_ino &&
1044 st_stdin.st_mode == st_stdout.st_mode);
1045 }
1046
1047 static struct commit_list *collect_parents(struct commit *head_commit,
1048 int *head_subsumed,
1049 int argc, const char **argv)
1050 {
1051 int i;
1052 struct commit_list *remoteheads = NULL, *parents, *next;
1053 struct commit_list **remotes = &remoteheads;
1054
1055 if (head_commit)
1056 remotes = &commit_list_insert(head_commit, remotes)->next;
1057 for (i = 0; i < argc; i++) {
1058 struct commit *commit = get_merge_parent(argv[i]);
1059 if (!commit)
1060 help_unknown_ref(argv[i], "merge",
1061 "not something we can merge");
1062 remotes = &commit_list_insert(commit, remotes)->next;
1063 }
1064 *remotes = NULL;
1065
1066 parents = reduce_heads(remoteheads);
1067
1068 *head_subsumed = 1; /* we will flip this to 0 when we find it */
1069 for (remoteheads = NULL, remotes = &remoteheads;
1070 parents;
1071 parents = next) {
1072 struct commit *commit = parents->item;
1073 next = parents->next;
1074 if (commit == head_commit)
1075 *head_subsumed = 0;
1076 else
1077 remotes = &commit_list_insert(commit, remotes)->next;
1078 }
1079 return remoteheads;
1080 }
1081
1082 int cmd_merge(int argc, const char **argv, const char *prefix)
1083 {
1084 unsigned char result_tree[20];
1085 unsigned char stash[20];
1086 unsigned char head_sha1[20];
1087 struct commit *head_commit;
1088 struct strbuf buf = STRBUF_INIT;
1089 const char *head_arg;
1090 int flag, i, ret = 0, head_subsumed;
1091 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1092 struct commit_list *common = NULL;
1093 const char *best_strategy = NULL, *wt_strategy = NULL;
1094 struct commit_list *remoteheads, *p;
1095 void *branch_to_free;
1096
1097 if (argc == 2 && !strcmp(argv[1], "-h"))
1098 usage_with_options(builtin_merge_usage, builtin_merge_options);
1099
1100 /*
1101 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1102 * current branch.
1103 */
1104 branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
1105 if (branch && starts_with(branch, "refs/heads/"))
1106 branch += 11;
1107 if (!branch || is_null_sha1(head_sha1))
1108 head_commit = NULL;
1109 else
1110 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1111
1112 git_config(git_merge_config, NULL);
1113
1114 if (branch_mergeoptions)
1115 parse_branch_merge_options(branch_mergeoptions);
1116 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1117 builtin_merge_usage, 0);
1118 if (shortlog_len < 0)
1119 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1120
1121 if (verbosity < 0 && show_progress == -1)
1122 show_progress = 0;
1123
1124 if (abort_current_merge) {
1125 int nargc = 2;
1126 const char *nargv[] = {"reset", "--merge", NULL};
1127
1128 if (!file_exists(git_path("MERGE_HEAD")))
1129 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1130
1131 /* Invoke 'git reset --merge' */
1132 ret = cmd_reset(nargc, nargv, prefix);
1133 goto done;
1134 }
1135
1136 if (read_cache_unmerged())
1137 die_resolve_conflict("merge");
1138
1139 if (file_exists(git_path("MERGE_HEAD"))) {
1140 /*
1141 * There is no unmerged entry, don't advise 'git
1142 * add/rm <file>', just 'git commit'.
1143 */
1144 if (advice_resolve_conflict)
1145 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1146 "Please, commit your changes before you merge."));
1147 else
1148 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1149 }
1150 if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
1151 if (advice_resolve_conflict)
1152 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1153 "Please, commit your changes before you merge."));
1154 else
1155 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1156 }
1157 resolve_undo_clear();
1158
1159 if (verbosity < 0)
1160 show_diffstat = 0;
1161
1162 if (squash) {
1163 if (fast_forward == FF_NO)
1164 die(_("You cannot combine --squash with --no-ff."));
1165 option_commit = 0;
1166 }
1167
1168 if (!abort_current_merge) {
1169 if (!argc) {
1170 if (default_to_upstream)
1171 argc = setup_with_upstream(&argv);
1172 else
1173 die(_("No commit specified and merge.defaultToUpstream not set."));
1174 } else if (argc == 1 && !strcmp(argv[0], "-"))
1175 argv[0] = "@{-1}";
1176 }
1177 if (!argc)
1178 usage_with_options(builtin_merge_usage,
1179 builtin_merge_options);
1180
1181 /*
1182 * This could be traditional "merge <msg> HEAD <commit>..." and
1183 * the way we can tell it is to see if the second token is HEAD,
1184 * but some people might have misused the interface and used a
1185 * commit-ish that is the same as HEAD there instead.
1186 * Traditional format never would have "-m" so it is an
1187 * additional safety measure to check for it.
1188 */
1189
1190 if (!have_message && head_commit &&
1191 is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
1192 strbuf_addstr(&merge_msg, argv[0]);
1193 head_arg = argv[1];
1194 argv += 2;
1195 argc -= 2;
1196 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1197 } else if (!head_commit) {
1198 struct commit *remote_head;
1199 /*
1200 * If the merged head is a valid one there is no reason
1201 * to forbid "git merge" into a branch yet to be born.
1202 * We do the same for "git pull".
1203 */
1204 if (argc != 1)
1205 die(_("Can merge only exactly one commit into "
1206 "empty head"));
1207 if (squash)
1208 die(_("Squash commit into empty head not supported yet"));
1209 if (fast_forward == FF_NO)
1210 die(_("Non-fast-forward commit does not make sense into "
1211 "an empty head"));
1212 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1213 remote_head = remoteheads->item;
1214 if (!remote_head)
1215 die(_("%s - not something we can merge"), argv[0]);
1216 read_empty(remote_head->object.sha1, 0);
1217 update_ref("initial pull", "HEAD", remote_head->object.sha1,
1218 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1219 goto done;
1220 } else {
1221 struct strbuf merge_names = STRBUF_INIT;
1222
1223 /* We are invoked directly as the first-class UI. */
1224 head_arg = "HEAD";
1225
1226 /*
1227 * All the rest are the commits being merged; prepare
1228 * the standard merge summary message to be appended
1229 * to the given message.
1230 */
1231 remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
1232 for (p = remoteheads; p; p = p->next)
1233 merge_name(merge_remote_util(p->item)->name, &merge_names);
1234
1235 if (!have_message || shortlog_len) {
1236 struct fmt_merge_msg_opts opts;
1237 memset(&opts, 0, sizeof(opts));
1238 opts.add_title = !have_message;
1239 opts.shortlog_len = shortlog_len;
1240 opts.credit_people = (0 < option_edit);
1241
1242 fmt_merge_msg(&merge_names, &merge_msg, &opts);
1243 if (merge_msg.len)
1244 strbuf_setlen(&merge_msg, merge_msg.len - 1);
1245 }
1246 }
1247
1248 if (!head_commit || !argc)
1249 usage_with_options(builtin_merge_usage,
1250 builtin_merge_options);
1251
1252 if (verify_signatures) {
1253 for (p = remoteheads; p; p = p->next) {
1254 struct commit *commit = p->item;
1255 char hex[41];
1256 struct signature_check signature_check;
1257 memset(&signature_check, 0, sizeof(signature_check));
1258
1259 check_commit_signature(commit, &signature_check);
1260
1261 strcpy(hex, find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
1262 switch (signature_check.result) {
1263 case 'G':
1264 break;
1265 case 'U':
1266 die(_("Commit %s has an untrusted GPG signature, "
1267 "allegedly by %s."), hex, signature_check.signer);
1268 case 'B':
1269 die(_("Commit %s has a bad GPG signature "
1270 "allegedly by %s."), hex, signature_check.signer);
1271 default: /* 'N' */
1272 die(_("Commit %s does not have a GPG signature."), hex);
1273 }
1274 if (verbosity >= 0 && signature_check.result == 'G')
1275 printf(_("Commit %s has a good GPG signature by %s\n"),
1276 hex, signature_check.signer);
1277
1278 signature_check_clear(&signature_check);
1279 }
1280 }
1281
1282 strbuf_addstr(&buf, "merge");
1283 for (p = remoteheads; p; p = p->next)
1284 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1285 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1286 strbuf_reset(&buf);
1287
1288 for (p = remoteheads; p; p = p->next) {
1289 struct commit *commit = p->item;
1290 strbuf_addf(&buf, "GITHEAD_%s",
1291 sha1_to_hex(commit->object.sha1));
1292 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1293 strbuf_reset(&buf);
1294 if (fast_forward != FF_ONLY &&
1295 merge_remote_util(commit) &&
1296 merge_remote_util(commit)->obj &&
1297 merge_remote_util(commit)->obj->type == OBJ_TAG)
1298 fast_forward = FF_NO;
1299 }
1300
1301 if (option_edit < 0)
1302 option_edit = default_edit_option();
1303
1304 if (!use_strategies) {
1305 if (!remoteheads)
1306 ; /* already up-to-date */
1307 else if (!remoteheads->next)
1308 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1309 else
1310 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1311 }
1312
1313 for (i = 0; i < use_strategies_nr; i++) {
1314 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1315 fast_forward = FF_NO;
1316 if (use_strategies[i]->attr & NO_TRIVIAL)
1317 allow_trivial = 0;
1318 }
1319
1320 if (!remoteheads)
1321 ; /* already up-to-date */
1322 else if (!remoteheads->next)
1323 common = get_merge_bases(head_commit, remoteheads->item, 1);
1324 else {
1325 struct commit_list *list = remoteheads;
1326 commit_list_insert(head_commit, &list);
1327 common = get_octopus_merge_bases(list);
1328 free(list);
1329 }
1330
1331 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
1332 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1333
1334 if (remoteheads && !common)
1335 ; /* No common ancestors found. We need a real merge. */
1336 else if (!remoteheads ||
1337 (!remoteheads->next && !common->next &&
1338 common->item == remoteheads->item)) {
1339 /*
1340 * If head can reach all the merge then we are up to date.
1341 * but first the most common case of merging one remote.
1342 */
1343 finish_up_to_date("Already up-to-date.");
1344 goto done;
1345 } else if (fast_forward != FF_NO && !remoteheads->next &&
1346 !common->next &&
1347 !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
1348 /* Again the most common case of merging one remote. */
1349 struct strbuf msg = STRBUF_INIT;
1350 struct commit *commit;
1351 char hex[41];
1352
1353 strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
1354
1355 if (verbosity >= 0)
1356 printf(_("Updating %s..%s\n"),
1357 hex,
1358 find_unique_abbrev(remoteheads->item->object.sha1,
1359 DEFAULT_ABBREV));
1360 strbuf_addstr(&msg, "Fast-forward");
1361 if (have_message)
1362 strbuf_addstr(&msg,
1363 " (no commit created; -m option ignored)");
1364 commit = remoteheads->item;
1365 if (!commit) {
1366 ret = 1;
1367 goto done;
1368 }
1369
1370 if (checkout_fast_forward(head_commit->object.sha1,
1371 commit->object.sha1,
1372 overwrite_ignore)) {
1373 ret = 1;
1374 goto done;
1375 }
1376
1377 finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
1378 drop_save();
1379 goto done;
1380 } else if (!remoteheads->next && common->next)
1381 ;
1382 /*
1383 * We are not doing octopus and not fast-forward. Need
1384 * a real merge.
1385 */
1386 else if (!remoteheads->next && !common->next && option_commit) {
1387 /*
1388 * We are not doing octopus, not fast-forward, and have
1389 * only one common.
1390 */
1391 refresh_cache(REFRESH_QUIET);
1392 if (allow_trivial && fast_forward != FF_ONLY) {
1393 /* See if it is really trivial. */
1394 git_committer_info(IDENT_STRICT);
1395 printf(_("Trying really trivial in-index merge...\n"));
1396 if (!read_tree_trivial(common->item->object.sha1,
1397 head_commit->object.sha1,
1398 remoteheads->item->object.sha1)) {
1399 ret = merge_trivial(head_commit, remoteheads);
1400 goto done;
1401 }
1402 printf(_("Nope.\n"));
1403 }
1404 } else {
1405 /*
1406 * An octopus. If we can reach all the remote we are up
1407 * to date.
1408 */
1409 int up_to_date = 1;
1410 struct commit_list *j;
1411
1412 for (j = remoteheads; j; j = j->next) {
1413 struct commit_list *common_one;
1414
1415 /*
1416 * Here we *have* to calculate the individual
1417 * merge_bases again, otherwise "git merge HEAD^
1418 * HEAD^^" would be missed.
1419 */
1420 common_one = get_merge_bases(head_commit, j->item, 1);
1421 if (hashcmp(common_one->item->object.sha1,
1422 j->item->object.sha1)) {
1423 up_to_date = 0;
1424 break;
1425 }
1426 }
1427 if (up_to_date) {
1428 finish_up_to_date("Already up-to-date. Yeeah!");
1429 goto done;
1430 }
1431 }
1432
1433 if (fast_forward == FF_ONLY)
1434 die(_("Not possible to fast-forward, aborting."));
1435
1436 /* We are going to make a new commit. */
1437 git_committer_info(IDENT_STRICT);
1438
1439 /*
1440 * At this point, we need a real merge. No matter what strategy
1441 * we use, it would operate on the index, possibly affecting the
1442 * working tree, and when resolved cleanly, have the desired
1443 * tree in the index -- this means that the index must be in
1444 * sync with the head commit. The strategies are responsible
1445 * to ensure this.
1446 */
1447 if (use_strategies_nr == 1 ||
1448 /*
1449 * Stash away the local changes so that we can try more than one.
1450 */
1451 save_state(stash))
1452 hashcpy(stash, null_sha1);
1453
1454 for (i = 0; i < use_strategies_nr; i++) {
1455 int ret;
1456 if (i) {
1457 printf(_("Rewinding the tree to pristine...\n"));
1458 restore_state(head_commit->object.sha1, stash);
1459 }
1460 if (use_strategies_nr != 1)
1461 printf(_("Trying merge strategy %s...\n"),
1462 use_strategies[i]->name);
1463 /*
1464 * Remember which strategy left the state in the working
1465 * tree.
1466 */
1467 wt_strategy = use_strategies[i]->name;
1468
1469 ret = try_merge_strategy(use_strategies[i]->name,
1470 common, remoteheads,
1471 head_commit, head_arg);
1472 if (!option_commit && !ret) {
1473 merge_was_ok = 1;
1474 /*
1475 * This is necessary here just to avoid writing
1476 * the tree, but later we will *not* exit with
1477 * status code 1 because merge_was_ok is set.
1478 */
1479 ret = 1;
1480 }
1481
1482 if (ret) {
1483 /*
1484 * The backend exits with 1 when conflicts are
1485 * left to be resolved, with 2 when it does not
1486 * handle the given merge at all.
1487 */
1488 if (ret == 1) {
1489 int cnt = evaluate_result();
1490
1491 if (best_cnt <= 0 || cnt <= best_cnt) {
1492 best_strategy = use_strategies[i]->name;
1493 best_cnt = cnt;
1494 }
1495 }
1496 if (merge_was_ok)
1497 break;
1498 else
1499 continue;
1500 }
1501
1502 /* Automerge succeeded. */
1503 write_tree_trivial(result_tree);
1504 automerge_was_ok = 1;
1505 break;
1506 }
1507
1508 /*
1509 * If we have a resulting tree, that means the strategy module
1510 * auto resolved the merge cleanly.
1511 */
1512 if (automerge_was_ok) {
1513 ret = finish_automerge(head_commit, head_subsumed,
1514 common, remoteheads,
1515 result_tree, wt_strategy);
1516 goto done;
1517 }
1518
1519 /*
1520 * Pick the result from the best strategy and have the user fix
1521 * it up.
1522 */
1523 if (!best_strategy) {
1524 restore_state(head_commit->object.sha1, stash);
1525 if (use_strategies_nr > 1)
1526 fprintf(stderr,
1527 _("No merge strategy handled the merge.\n"));
1528 else
1529 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1530 use_strategies[0]->name);
1531 ret = 2;
1532 goto done;
1533 } else if (best_strategy == wt_strategy)
1534 ; /* We already have its result in the working tree. */
1535 else {
1536 printf(_("Rewinding the tree to pristine...\n"));
1537 restore_state(head_commit->object.sha1, stash);
1538 printf(_("Using the %s to prepare resolving by hand.\n"),
1539 best_strategy);
1540 try_merge_strategy(best_strategy, common, remoteheads,
1541 head_commit, head_arg);
1542 }
1543
1544 if (squash)
1545 finish(head_commit, remoteheads, NULL, NULL);
1546 else
1547 write_merge_state(remoteheads);
1548
1549 if (merge_was_ok)
1550 fprintf(stderr, _("Automatic merge went well; "
1551 "stopped before committing as requested\n"));
1552 else
1553 ret = suggest_conflicts(option_renormalize);
1554
1555 done:
1556 free(branch_to_free);
1557 return ret;
1558 }