Update draft release notes to 1.8.3.4
[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 "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
32 #define DEFAULT_TWOHEAD (1<<0)
33 #define DEFAULT_OCTOPUS (1<<1)
34 #define NO_FAST_FORWARD (1<<2)
35 #define NO_TRIVIAL (1<<3)
36
37 struct strategy {
38 const char *name;
39 unsigned attr;
40 };
41
42 static const char * const builtin_merge_usage[] = {
43 N_("git merge [options] [<commit>...]"),
44 N_("git merge [options] <msg> HEAD <commit>"),
45 N_("git merge --abort"),
46 NULL
47 };
48
49 static int show_diffstat = 1, shortlog_len = -1, squash;
50 static int option_commit = 1, allow_fast_forward = 1;
51 static int fast_forward_only, option_edit = -1;
52 static int allow_trivial = 1, have_message, verify_signatures;
53 static int overwrite_ignore = 1;
54 static struct strbuf merge_msg = STRBUF_INIT;
55 static struct strategy **use_strategies;
56 static size_t use_strategies_nr, use_strategies_alloc;
57 static const char **xopts;
58 static size_t xopts_nr, xopts_alloc;
59 static const char *branch;
60 static char *branch_mergeoptions;
61 static int option_renormalize;
62 static int verbosity;
63 static int allow_rerere_auto;
64 static int abort_current_merge;
65 static int show_progress = -1;
66 static int default_to_upstream;
67 static const char *sign_commit;
68
69 static struct strategy all_strategy[] = {
70 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
71 { "octopus", DEFAULT_OCTOPUS },
72 { "resolve", 0 },
73 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
74 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
75 };
76
77 static const char *pull_twohead, *pull_octopus;
78
79 static int option_parse_message(const struct option *opt,
80 const char *arg, int unset)
81 {
82 struct strbuf *buf = opt->value;
83
84 if (unset)
85 strbuf_setlen(buf, 0);
86 else if (arg) {
87 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
88 have_message = 1;
89 } else
90 return error(_("switch `m' requires a value"));
91 return 0;
92 }
93
94 static struct strategy *get_strategy(const char *name)
95 {
96 int i;
97 struct strategy *ret;
98 static struct cmdnames main_cmds, other_cmds;
99 static int loaded;
100
101 if (!name)
102 return NULL;
103
104 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
105 if (!strcmp(name, all_strategy[i].name))
106 return &all_strategy[i];
107
108 if (!loaded) {
109 struct cmdnames not_strategies;
110 loaded = 1;
111
112 memset(&not_strategies, 0, sizeof(struct cmdnames));
113 load_command_list("git-merge-", &main_cmds, &other_cmds);
114 for (i = 0; i < main_cmds.cnt; i++) {
115 int j, found = 0;
116 struct cmdname *ent = main_cmds.names[i];
117 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
118 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
119 && !all_strategy[j].name[ent->len])
120 found = 1;
121 if (!found)
122 add_cmdname(&not_strategies, ent->name, ent->len);
123 }
124 exclude_cmds(&main_cmds, &not_strategies);
125 }
126 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
127 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
128 fprintf(stderr, _("Available strategies are:"));
129 for (i = 0; i < main_cmds.cnt; i++)
130 fprintf(stderr, " %s", main_cmds.names[i]->name);
131 fprintf(stderr, ".\n");
132 if (other_cmds.cnt) {
133 fprintf(stderr, _("Available custom strategies are:"));
134 for (i = 0; i < other_cmds.cnt; i++)
135 fprintf(stderr, " %s", other_cmds.names[i]->name);
136 fprintf(stderr, ".\n");
137 }
138 exit(1);
139 }
140
141 ret = xcalloc(1, sizeof(struct strategy));
142 ret->name = xstrdup(name);
143 ret->attr = NO_TRIVIAL;
144 return ret;
145 }
146
147 static void append_strategy(struct strategy *s)
148 {
149 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
150 use_strategies[use_strategies_nr++] = s;
151 }
152
153 static int option_parse_strategy(const struct option *opt,
154 const char *name, int unset)
155 {
156 if (unset)
157 return 0;
158
159 append_strategy(get_strategy(name));
160 return 0;
161 }
162
163 static int option_parse_x(const struct option *opt,
164 const char *arg, int unset)
165 {
166 if (unset)
167 return 0;
168
169 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
170 xopts[xopts_nr++] = xstrdup(arg);
171 return 0;
172 }
173
174 static int option_parse_n(const struct option *opt,
175 const char *arg, int unset)
176 {
177 show_diffstat = unset;
178 return 0;
179 }
180
181 static struct option builtin_merge_options[] = {
182 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
183 N_("do not show a diffstat at the end of the merge"),
184 PARSE_OPT_NOARG, option_parse_n },
185 OPT_BOOLEAN(0, "stat", &show_diffstat,
186 N_("show a diffstat at the end of the merge")),
187 OPT_BOOLEAN(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
188 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
189 N_("add (at most <n>) entries from shortlog to merge commit message"),
190 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
191 OPT_BOOLEAN(0, "squash", &squash,
192 N_("create a single commit instead of doing a merge")),
193 OPT_BOOLEAN(0, "commit", &option_commit,
194 N_("perform a commit if the merge succeeds (default)")),
195 OPT_BOOL('e', "edit", &option_edit,
196 N_("edit message before committing")),
197 OPT_BOOLEAN(0, "ff", &allow_fast_forward,
198 N_("allow fast-forward (default)")),
199 OPT_BOOLEAN(0, "ff-only", &fast_forward_only,
200 N_("abort if fast-forward is not possible")),
201 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
202 OPT_BOOL(0, "verify-signatures", &verify_signatures,
203 N_("Verify that the named commit has a valid GPG signature")),
204 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
205 N_("merge strategy to use"), option_parse_strategy),
206 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
207 N_("option for selected merge strategy"), option_parse_x),
208 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
209 N_("merge commit message (for a non-fast-forward merge)"),
210 option_parse_message),
211 OPT__VERBOSITY(&verbosity),
212 OPT_BOOLEAN(0, "abort", &abort_current_merge,
213 N_("abort the current in-progress merge")),
214 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
215 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key id"),
216 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
217 OPT_BOOLEAN(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
218 OPT_END()
219 };
220
221 /* Cleans up metadata that is uninteresting after a succeeded merge. */
222 static void drop_save(void)
223 {
224 unlink(git_path("MERGE_HEAD"));
225 unlink(git_path("MERGE_MSG"));
226 unlink(git_path("MERGE_MODE"));
227 }
228
229 static int save_state(unsigned char *stash)
230 {
231 int len;
232 struct child_process cp;
233 struct strbuf buffer = STRBUF_INIT;
234 const char *argv[] = {"stash", "create", NULL};
235
236 memset(&cp, 0, sizeof(cp));
237 cp.argv = argv;
238 cp.out = -1;
239 cp.git_cmd = 1;
240
241 if (start_command(&cp))
242 die(_("could not run stash."));
243 len = strbuf_read(&buffer, cp.out, 1024);
244 close(cp.out);
245
246 if (finish_command(&cp) || len < 0)
247 die(_("stash failed"));
248 else if (!len) /* no changes */
249 return -1;
250 strbuf_setlen(&buffer, buffer.len-1);
251 if (get_sha1(buffer.buf, stash))
252 die(_("not a valid object: %s"), buffer.buf);
253 return 0;
254 }
255
256 static void read_empty(unsigned const char *sha1, int verbose)
257 {
258 int i = 0;
259 const char *args[7];
260
261 args[i++] = "read-tree";
262 if (verbose)
263 args[i++] = "-v";
264 args[i++] = "-m";
265 args[i++] = "-u";
266 args[i++] = EMPTY_TREE_SHA1_HEX;
267 args[i++] = sha1_to_hex(sha1);
268 args[i] = NULL;
269
270 if (run_command_v_opt(args, RUN_GIT_CMD))
271 die(_("read-tree failed"));
272 }
273
274 static void reset_hard(unsigned const char *sha1, int verbose)
275 {
276 int i = 0;
277 const char *args[6];
278
279 args[i++] = "read-tree";
280 if (verbose)
281 args[i++] = "-v";
282 args[i++] = "--reset";
283 args[i++] = "-u";
284 args[i++] = sha1_to_hex(sha1);
285 args[i] = NULL;
286
287 if (run_command_v_opt(args, RUN_GIT_CMD))
288 die(_("read-tree failed"));
289 }
290
291 static void restore_state(const unsigned char *head,
292 const unsigned char *stash)
293 {
294 struct strbuf sb = STRBUF_INIT;
295 const char *args[] = { "stash", "apply", NULL, NULL };
296
297 if (is_null_sha1(stash))
298 return;
299
300 reset_hard(head, 1);
301
302 args[2] = sha1_to_hex(stash);
303
304 /*
305 * It is OK to ignore error here, for example when there was
306 * nothing to restore.
307 */
308 run_command_v_opt(args, RUN_GIT_CMD);
309
310 strbuf_release(&sb);
311 refresh_cache(REFRESH_QUIET);
312 }
313
314 /* This is called when no merge was necessary. */
315 static void finish_up_to_date(const char *msg)
316 {
317 if (verbosity >= 0)
318 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
319 drop_save();
320 }
321
322 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
323 {
324 struct rev_info rev;
325 struct strbuf out = STRBUF_INIT;
326 struct commit_list *j;
327 const char *filename;
328 int fd;
329 struct pretty_print_context ctx = {0};
330
331 printf(_("Squash commit -- not updating HEAD\n"));
332 filename = git_path("SQUASH_MSG");
333 fd = open(filename, O_WRONLY | O_CREAT, 0666);
334 if (fd < 0)
335 die_errno(_("Could not write to '%s'"), filename);
336
337 init_revisions(&rev, NULL);
338 rev.ignore_merges = 1;
339 rev.commit_format = CMIT_FMT_MEDIUM;
340
341 commit->object.flags |= UNINTERESTING;
342 add_pending_object(&rev, &commit->object, NULL);
343
344 for (j = remoteheads; j; j = j->next)
345 add_pending_object(&rev, &j->item->object, NULL);
346
347 setup_revisions(0, NULL, &rev, NULL);
348 if (prepare_revision_walk(&rev))
349 die(_("revision walk setup failed"));
350
351 ctx.abbrev = rev.abbrev;
352 ctx.date_mode = rev.date_mode;
353 ctx.fmt = rev.commit_format;
354
355 strbuf_addstr(&out, "Squashed commit of the following:\n");
356 while ((commit = get_revision(&rev)) != NULL) {
357 strbuf_addch(&out, '\n');
358 strbuf_addf(&out, "commit %s\n",
359 sha1_to_hex(commit->object.sha1));
360 pretty_print_commit(&ctx, commit, &out);
361 }
362 if (write(fd, out.buf, out.len) < 0)
363 die_errno(_("Writing SQUASH_MSG"));
364 if (close(fd))
365 die_errno(_("Finishing SQUASH_MSG"));
366 strbuf_release(&out);
367 }
368
369 static void finish(struct commit *head_commit,
370 struct commit_list *remoteheads,
371 const unsigned char *new_head, const char *msg)
372 {
373 struct strbuf reflog_message = STRBUF_INIT;
374 const unsigned char *head = head_commit->object.sha1;
375
376 if (!msg)
377 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
378 else {
379 if (verbosity >= 0)
380 printf("%s\n", msg);
381 strbuf_addf(&reflog_message, "%s: %s",
382 getenv("GIT_REFLOG_ACTION"), msg);
383 }
384 if (squash) {
385 squash_message(head_commit, remoteheads);
386 } else {
387 if (verbosity >= 0 && !merge_msg.len)
388 printf(_("No merge message -- not updating HEAD\n"));
389 else {
390 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
391 update_ref(reflog_message.buf, "HEAD",
392 new_head, head, 0,
393 DIE_ON_ERR);
394 /*
395 * We ignore errors in 'gc --auto', since the
396 * user should see them.
397 */
398 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
399 }
400 }
401 if (new_head && show_diffstat) {
402 struct diff_options opts;
403 diff_setup(&opts);
404 opts.stat_width = -1; /* use full terminal width */
405 opts.stat_graph_width = -1; /* respect statGraphWidth config */
406 opts.output_format |=
407 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
408 opts.detect_rename = DIFF_DETECT_RENAME;
409 diff_setup_done(&opts);
410 diff_tree_sha1(head, new_head, "", &opts);
411 diffcore_std(&opts);
412 diff_flush(&opts);
413 }
414
415 /* Run a post-merge hook */
416 run_hook(NULL, "post-merge", squash ? "1" : "0", NULL);
417
418 strbuf_release(&reflog_message);
419 }
420
421 /* Get the name for the merge commit's message. */
422 static void merge_name(const char *remote, struct strbuf *msg)
423 {
424 struct commit *remote_head;
425 unsigned char branch_head[20];
426 struct strbuf buf = STRBUF_INIT;
427 struct strbuf bname = STRBUF_INIT;
428 const char *ptr;
429 char *found_ref;
430 int len, early;
431
432 strbuf_branchname(&bname, remote);
433 remote = bname.buf;
434
435 memset(branch_head, 0, sizeof(branch_head));
436 remote_head = get_merge_parent(remote);
437 if (!remote_head)
438 die(_("'%s' does not point to a commit"), remote);
439
440 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
441 if (!prefixcmp(found_ref, "refs/heads/")) {
442 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
443 sha1_to_hex(branch_head), remote);
444 goto cleanup;
445 }
446 if (!prefixcmp(found_ref, "refs/tags/")) {
447 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
448 sha1_to_hex(branch_head), remote);
449 goto cleanup;
450 }
451 if (!prefixcmp(found_ref, "refs/remotes/")) {
452 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
453 sha1_to_hex(branch_head), remote);
454 goto cleanup;
455 }
456 }
457
458 /* See if remote matches <name>^^^.. or <name>~<number> */
459 for (len = 0, ptr = remote + strlen(remote);
460 remote < ptr && ptr[-1] == '^';
461 ptr--)
462 len++;
463 if (len)
464 early = 1;
465 else {
466 early = 0;
467 ptr = strrchr(remote, '~');
468 if (ptr) {
469 int seen_nonzero = 0;
470
471 len++; /* count ~ */
472 while (*++ptr && isdigit(*ptr)) {
473 seen_nonzero |= (*ptr != '0');
474 len++;
475 }
476 if (*ptr)
477 len = 0; /* not ...~<number> */
478 else if (seen_nonzero)
479 early = 1;
480 else if (len == 1)
481 early = 1; /* "name~" is "name~1"! */
482 }
483 }
484 if (len) {
485 struct strbuf truname = STRBUF_INIT;
486 strbuf_addstr(&truname, "refs/heads/");
487 strbuf_addstr(&truname, remote);
488 strbuf_setlen(&truname, truname.len - len);
489 if (ref_exists(truname.buf)) {
490 strbuf_addf(msg,
491 "%s\t\tbranch '%s'%s of .\n",
492 sha1_to_hex(remote_head->object.sha1),
493 truname.buf + 11,
494 (early ? " (early part)" : ""));
495 strbuf_release(&truname);
496 goto cleanup;
497 }
498 }
499
500 if (!strcmp(remote, "FETCH_HEAD") &&
501 !access(git_path("FETCH_HEAD"), R_OK)) {
502 const char *filename;
503 FILE *fp;
504 struct strbuf line = STRBUF_INIT;
505 char *ptr;
506
507 filename = git_path("FETCH_HEAD");
508 fp = fopen(filename, "r");
509 if (!fp)
510 die_errno(_("could not open '%s' for reading"),
511 filename);
512 strbuf_getline(&line, fp, '\n');
513 fclose(fp);
514 ptr = strstr(line.buf, "\tnot-for-merge\t");
515 if (ptr)
516 strbuf_remove(&line, ptr-line.buf+1, 13);
517 strbuf_addbuf(msg, &line);
518 strbuf_release(&line);
519 goto cleanup;
520 }
521
522 if (remote_head->util) {
523 struct merge_remote_desc *desc;
524 desc = merge_remote_util(remote_head);
525 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
526 strbuf_addf(msg, "%s\t\t%s '%s'\n",
527 sha1_to_hex(desc->obj->sha1),
528 typename(desc->obj->type),
529 remote);
530 goto cleanup;
531 }
532 }
533
534 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
535 sha1_to_hex(remote_head->object.sha1), remote);
536 cleanup:
537 strbuf_release(&buf);
538 strbuf_release(&bname);
539 }
540
541 static void parse_branch_merge_options(char *bmo)
542 {
543 const char **argv;
544 int argc;
545
546 if (!bmo)
547 return;
548 argc = split_cmdline(bmo, &argv);
549 if (argc < 0)
550 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
551 split_cmdline_strerror(argc));
552 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
553 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
554 argc++;
555 argv[0] = "branch.*.mergeoptions";
556 parse_options(argc, argv, NULL, builtin_merge_options,
557 builtin_merge_usage, 0);
558 free(argv);
559 }
560
561 static int git_merge_config(const char *k, const char *v, void *cb)
562 {
563 int status;
564
565 if (branch && !prefixcmp(k, "branch.") &&
566 !prefixcmp(k + 7, branch) &&
567 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
568 free(branch_mergeoptions);
569 branch_mergeoptions = xstrdup(v);
570 return 0;
571 }
572
573 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
574 show_diffstat = git_config_bool(k, v);
575 else if (!strcmp(k, "pull.twohead"))
576 return git_config_string(&pull_twohead, k, v);
577 else if (!strcmp(k, "pull.octopus"))
578 return git_config_string(&pull_octopus, k, v);
579 else if (!strcmp(k, "merge.renormalize"))
580 option_renormalize = git_config_bool(k, v);
581 else if (!strcmp(k, "merge.ff")) {
582 int boolval = git_config_maybe_bool(k, v);
583 if (0 <= boolval) {
584 allow_fast_forward = boolval;
585 } else if (v && !strcmp(v, "only")) {
586 allow_fast_forward = 1;
587 fast_forward_only = 1;
588 } /* do not barf on values from future versions of git */
589 return 0;
590 } else if (!strcmp(k, "merge.defaulttoupstream")) {
591 default_to_upstream = git_config_bool(k, v);
592 return 0;
593 }
594
595 status = fmt_merge_msg_config(k, v, cb);
596 if (status)
597 return status;
598 status = git_gpg_config(k, v, NULL);
599 if (status)
600 return status;
601 return git_diff_ui_config(k, v, cb);
602 }
603
604 static int read_tree_trivial(unsigned char *common, unsigned char *head,
605 unsigned char *one)
606 {
607 int i, nr_trees = 0;
608 struct tree *trees[MAX_UNPACK_TREES];
609 struct tree_desc t[MAX_UNPACK_TREES];
610 struct unpack_trees_options opts;
611
612 memset(&opts, 0, sizeof(opts));
613 opts.head_idx = 2;
614 opts.src_index = &the_index;
615 opts.dst_index = &the_index;
616 opts.update = 1;
617 opts.verbose_update = 1;
618 opts.trivial_merges_only = 1;
619 opts.merge = 1;
620 trees[nr_trees] = parse_tree_indirect(common);
621 if (!trees[nr_trees++])
622 return -1;
623 trees[nr_trees] = parse_tree_indirect(head);
624 if (!trees[nr_trees++])
625 return -1;
626 trees[nr_trees] = parse_tree_indirect(one);
627 if (!trees[nr_trees++])
628 return -1;
629 opts.fn = threeway_merge;
630 cache_tree_free(&active_cache_tree);
631 for (i = 0; i < nr_trees; i++) {
632 parse_tree(trees[i]);
633 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
634 }
635 if (unpack_trees(nr_trees, t, &opts))
636 return -1;
637 return 0;
638 }
639
640 static void write_tree_trivial(unsigned char *sha1)
641 {
642 if (write_cache_as_tree(sha1, 0, NULL))
643 die(_("git write-tree failed to write a tree"));
644 }
645
646 static int try_merge_strategy(const char *strategy, struct commit_list *common,
647 struct commit_list *remoteheads,
648 struct commit *head, const char *head_arg)
649 {
650 int index_fd;
651 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
652
653 index_fd = hold_locked_index(lock, 1);
654 refresh_cache(REFRESH_QUIET);
655 if (active_cache_changed &&
656 (write_cache(index_fd, active_cache, active_nr) ||
657 commit_locked_index(lock)))
658 return error(_("Unable to write index."));
659 rollback_lock_file(lock);
660
661 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
662 int clean, x;
663 struct commit *result;
664 struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
665 int index_fd;
666 struct commit_list *reversed = NULL;
667 struct merge_options o;
668 struct commit_list *j;
669
670 if (remoteheads->next) {
671 error(_("Not handling anything other than two heads merge."));
672 return 2;
673 }
674
675 init_merge_options(&o);
676 if (!strcmp(strategy, "subtree"))
677 o.subtree_shift = "";
678
679 o.renormalize = option_renormalize;
680 o.show_rename_progress =
681 show_progress == -1 ? isatty(2) : show_progress;
682
683 for (x = 0; x < xopts_nr; x++)
684 if (parse_merge_opt(&o, xopts[x]))
685 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
686
687 o.branch1 = head_arg;
688 o.branch2 = merge_remote_util(remoteheads->item)->name;
689
690 for (j = common; j; j = j->next)
691 commit_list_insert(j->item, &reversed);
692
693 index_fd = hold_locked_index(lock, 1);
694 clean = merge_recursive(&o, head,
695 remoteheads->item, reversed, &result);
696 if (active_cache_changed &&
697 (write_cache(index_fd, active_cache, active_nr) ||
698 commit_locked_index(lock)))
699 die (_("unable to write %s"), get_index_file());
700 rollback_lock_file(lock);
701 return clean ? 0 : 1;
702 } else {
703 return try_merge_command(strategy, xopts_nr, xopts,
704 common, head_arg, remoteheads);
705 }
706 }
707
708 static void count_diff_files(struct diff_queue_struct *q,
709 struct diff_options *opt, void *data)
710 {
711 int *count = data;
712
713 (*count) += q->nr;
714 }
715
716 static int count_unmerged_entries(void)
717 {
718 int i, ret = 0;
719
720 for (i = 0; i < active_nr; i++)
721 if (ce_stage(active_cache[i]))
722 ret++;
723
724 return ret;
725 }
726
727 static void split_merge_strategies(const char *string, struct strategy **list,
728 int *nr, int *alloc)
729 {
730 char *p, *q, *buf;
731
732 if (!string)
733 return;
734
735 buf = xstrdup(string);
736 q = buf;
737 for (;;) {
738 p = strchr(q, ' ');
739 if (!p) {
740 ALLOC_GROW(*list, *nr + 1, *alloc);
741 (*list)[(*nr)++].name = xstrdup(q);
742 free(buf);
743 return;
744 } else {
745 *p = '\0';
746 ALLOC_GROW(*list, *nr + 1, *alloc);
747 (*list)[(*nr)++].name = xstrdup(q);
748 q = ++p;
749 }
750 }
751 }
752
753 static void add_strategies(const char *string, unsigned attr)
754 {
755 struct strategy *list = NULL;
756 int list_alloc = 0, list_nr = 0, i;
757
758 memset(&list, 0, sizeof(list));
759 split_merge_strategies(string, &list, &list_nr, &list_alloc);
760 if (list) {
761 for (i = 0; i < list_nr; i++)
762 append_strategy(get_strategy(list[i].name));
763 return;
764 }
765 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
766 if (all_strategy[i].attr & attr)
767 append_strategy(&all_strategy[i]);
768
769 }
770
771 static void write_merge_msg(struct strbuf *msg)
772 {
773 const char *filename = git_path("MERGE_MSG");
774 int fd = open(filename, O_WRONLY | O_CREAT, 0666);
775 if (fd < 0)
776 die_errno(_("Could not open '%s' for writing"),
777 filename);
778 if (write_in_full(fd, msg->buf, msg->len) != msg->len)
779 die_errno(_("Could not write to '%s'"), filename);
780 close(fd);
781 }
782
783 static void read_merge_msg(struct strbuf *msg)
784 {
785 const char *filename = git_path("MERGE_MSG");
786 strbuf_reset(msg);
787 if (strbuf_read_file(msg, filename, 0) < 0)
788 die_errno(_("Could not read from '%s'"), filename);
789 }
790
791 static void write_merge_state(struct commit_list *);
792 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
793 {
794 if (err_msg)
795 error("%s", err_msg);
796 fprintf(stderr,
797 _("Not committing merge; use 'git commit' to complete the merge.\n"));
798 write_merge_state(remoteheads);
799 exit(1);
800 }
801
802 static const char merge_editor_comment[] =
803 N_("Please enter a commit message to explain why this merge is necessary,\n"
804 "especially if it merges an updated upstream into a topic branch.\n"
805 "\n"
806 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
807 "the commit.\n");
808
809 static void prepare_to_commit(struct commit_list *remoteheads)
810 {
811 struct strbuf msg = STRBUF_INIT;
812 strbuf_addbuf(&msg, &merge_msg);
813 strbuf_addch(&msg, '\n');
814 if (0 < option_edit)
815 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
816 write_merge_msg(&msg);
817 if (run_hook(get_index_file(), "prepare-commit-msg",
818 git_path("MERGE_MSG"), "merge", NULL, NULL))
819 abort_commit(remoteheads, NULL);
820 if (0 < option_edit) {
821 if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
822 abort_commit(remoteheads, NULL);
823 }
824 read_merge_msg(&msg);
825 stripspace(&msg, 0 < option_edit);
826 if (!msg.len)
827 abort_commit(remoteheads, _("Empty commit message."));
828 strbuf_release(&merge_msg);
829 strbuf_addbuf(&merge_msg, &msg);
830 strbuf_release(&msg);
831 }
832
833 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
834 {
835 unsigned char result_tree[20], result_commit[20];
836 struct commit_list *parent = xmalloc(sizeof(*parent));
837
838 write_tree_trivial(result_tree);
839 printf(_("Wonderful.\n"));
840 parent->item = head;
841 parent->next = xmalloc(sizeof(*parent->next));
842 parent->next->item = remoteheads->item;
843 parent->next->next = NULL;
844 prepare_to_commit(remoteheads);
845 if (commit_tree(&merge_msg, result_tree, parent, result_commit, NULL,
846 sign_commit))
847 die(_("failed to write commit object"));
848 finish(head, remoteheads, result_commit, "In-index merge");
849 drop_save();
850 return 0;
851 }
852
853 static int finish_automerge(struct commit *head,
854 int head_subsumed,
855 struct commit_list *common,
856 struct commit_list *remoteheads,
857 unsigned char *result_tree,
858 const char *wt_strategy)
859 {
860 struct commit_list *parents = NULL;
861 struct strbuf buf = STRBUF_INIT;
862 unsigned char result_commit[20];
863
864 free_commit_list(common);
865 parents = remoteheads;
866 if (!head_subsumed || !allow_fast_forward)
867 commit_list_insert(head, &parents);
868 strbuf_addch(&merge_msg, '\n');
869 prepare_to_commit(remoteheads);
870 if (commit_tree(&merge_msg, result_tree, parents, result_commit,
871 NULL, sign_commit))
872 die(_("failed to write commit object"));
873 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
874 finish(head, remoteheads, result_commit, buf.buf);
875 strbuf_release(&buf);
876 drop_save();
877 return 0;
878 }
879
880 static int suggest_conflicts(int renormalizing)
881 {
882 const char *filename;
883 FILE *fp;
884 int pos;
885
886 filename = git_path("MERGE_MSG");
887 fp = fopen(filename, "a");
888 if (!fp)
889 die_errno(_("Could not open '%s' for writing"), filename);
890 fprintf(fp, "\nConflicts:\n");
891 for (pos = 0; pos < active_nr; pos++) {
892 struct cache_entry *ce = active_cache[pos];
893
894 if (ce_stage(ce)) {
895 fprintf(fp, "\t%s\n", ce->name);
896 while (pos + 1 < active_nr &&
897 !strcmp(ce->name,
898 active_cache[pos + 1]->name))
899 pos++;
900 }
901 }
902 fclose(fp);
903 rerere(allow_rerere_auto);
904 printf(_("Automatic merge failed; "
905 "fix conflicts and then commit the result.\n"));
906 return 1;
907 }
908
909 static struct commit *is_old_style_invocation(int argc, const char **argv,
910 const unsigned char *head)
911 {
912 struct commit *second_token = NULL;
913 if (argc > 2) {
914 unsigned char second_sha1[20];
915
916 if (get_sha1(argv[1], second_sha1))
917 return NULL;
918 second_token = lookup_commit_reference_gently(second_sha1, 0);
919 if (!second_token)
920 die(_("'%s' is not a commit"), argv[1]);
921 if (hashcmp(second_token->object.sha1, head))
922 return NULL;
923 }
924 return second_token;
925 }
926
927 static int evaluate_result(void)
928 {
929 int cnt = 0;
930 struct rev_info rev;
931
932 /* Check how many files differ. */
933 init_revisions(&rev, "");
934 setup_revisions(0, NULL, &rev, NULL);
935 rev.diffopt.output_format |=
936 DIFF_FORMAT_CALLBACK;
937 rev.diffopt.format_callback = count_diff_files;
938 rev.diffopt.format_callback_data = &cnt;
939 run_diff_files(&rev, 0);
940
941 /*
942 * Check how many unmerged entries are
943 * there.
944 */
945 cnt += count_unmerged_entries();
946
947 return cnt;
948 }
949
950 /*
951 * Pretend as if the user told us to merge with the tracking
952 * branch we have for the upstream of the current branch
953 */
954 static int setup_with_upstream(const char ***argv)
955 {
956 struct branch *branch = branch_get(NULL);
957 int i;
958 const char **args;
959
960 if (!branch)
961 die(_("No current branch."));
962 if (!branch->remote)
963 die(_("No remote for the current branch."));
964 if (!branch->merge_nr)
965 die(_("No default upstream defined for the current branch."));
966
967 args = xcalloc(branch->merge_nr + 1, sizeof(char *));
968 for (i = 0; i < branch->merge_nr; i++) {
969 if (!branch->merge[i]->dst)
970 die(_("No remote tracking branch for %s from %s"),
971 branch->merge[i]->src, branch->remote_name);
972 args[i] = branch->merge[i]->dst;
973 }
974 args[i] = NULL;
975 *argv = args;
976 return i;
977 }
978
979 static void write_merge_state(struct commit_list *remoteheads)
980 {
981 const char *filename;
982 int fd;
983 struct commit_list *j;
984 struct strbuf buf = STRBUF_INIT;
985
986 for (j = remoteheads; j; j = j->next) {
987 unsigned const char *sha1;
988 struct commit *c = j->item;
989 if (c->util && merge_remote_util(c)->obj) {
990 sha1 = merge_remote_util(c)->obj->sha1;
991 } else {
992 sha1 = c->object.sha1;
993 }
994 strbuf_addf(&buf, "%s\n", sha1_to_hex(sha1));
995 }
996 filename = git_path("MERGE_HEAD");
997 fd = open(filename, O_WRONLY | O_CREAT, 0666);
998 if (fd < 0)
999 die_errno(_("Could not open '%s' for writing"), filename);
1000 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1001 die_errno(_("Could not write to '%s'"), filename);
1002 close(fd);
1003 strbuf_addch(&merge_msg, '\n');
1004 write_merge_msg(&merge_msg);
1005
1006 filename = git_path("MERGE_MODE");
1007 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
1008 if (fd < 0)
1009 die_errno(_("Could not open '%s' for writing"), filename);
1010 strbuf_reset(&buf);
1011 if (!allow_fast_forward)
1012 strbuf_addf(&buf, "no-ff");
1013 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1014 die_errno(_("Could not write to '%s'"), filename);
1015 close(fd);
1016 }
1017
1018 static int default_edit_option(void)
1019 {
1020 static const char name[] = "GIT_MERGE_AUTOEDIT";
1021 const char *e = getenv(name);
1022 struct stat st_stdin, st_stdout;
1023
1024 if (have_message)
1025 /* an explicit -m msg without --[no-]edit */
1026 return 0;
1027
1028 if (e) {
1029 int v = git_config_maybe_bool(name, e);
1030 if (v < 0)
1031 die("Bad value '%s' in environment '%s'", e, name);
1032 return v;
1033 }
1034
1035 /* Use editor if stdin and stdout are the same and is a tty */
1036 return (!fstat(0, &st_stdin) &&
1037 !fstat(1, &st_stdout) &&
1038 isatty(0) && isatty(1) &&
1039 st_stdin.st_dev == st_stdout.st_dev &&
1040 st_stdin.st_ino == st_stdout.st_ino &&
1041 st_stdin.st_mode == st_stdout.st_mode);
1042 }
1043
1044 static struct commit_list *collect_parents(struct commit *head_commit,
1045 int *head_subsumed,
1046 int argc, const char **argv)
1047 {
1048 int i;
1049 struct commit_list *remoteheads = NULL, *parents, *next;
1050 struct commit_list **remotes = &remoteheads;
1051
1052 if (head_commit)
1053 remotes = &commit_list_insert(head_commit, remotes)->next;
1054 for (i = 0; i < argc; i++) {
1055 struct commit *commit = get_merge_parent(argv[i]);
1056 if (!commit)
1057 help_unknown_ref(argv[i], "merge",
1058 "not something we can merge");
1059 remotes = &commit_list_insert(commit, remotes)->next;
1060 }
1061 *remotes = NULL;
1062
1063 parents = reduce_heads(remoteheads);
1064
1065 *head_subsumed = 1; /* we will flip this to 0 when we find it */
1066 for (remoteheads = NULL, remotes = &remoteheads;
1067 parents;
1068 parents = next) {
1069 struct commit *commit = parents->item;
1070 next = parents->next;
1071 if (commit == head_commit)
1072 *head_subsumed = 0;
1073 else
1074 remotes = &commit_list_insert(commit, remotes)->next;
1075 }
1076 return remoteheads;
1077 }
1078
1079 int cmd_merge(int argc, const char **argv, const char *prefix)
1080 {
1081 unsigned char result_tree[20];
1082 unsigned char stash[20];
1083 unsigned char head_sha1[20];
1084 struct commit *head_commit;
1085 struct strbuf buf = STRBUF_INIT;
1086 const char *head_arg;
1087 int flag, i, ret = 0, head_subsumed;
1088 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1089 struct commit_list *common = NULL;
1090 const char *best_strategy = NULL, *wt_strategy = NULL;
1091 struct commit_list *remoteheads, *p;
1092 void *branch_to_free;
1093
1094 if (argc == 2 && !strcmp(argv[1], "-h"))
1095 usage_with_options(builtin_merge_usage, builtin_merge_options);
1096
1097 /*
1098 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1099 * current branch.
1100 */
1101 branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
1102 if (branch && !prefixcmp(branch, "refs/heads/"))
1103 branch += 11;
1104 if (!branch || is_null_sha1(head_sha1))
1105 head_commit = NULL;
1106 else
1107 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1108
1109 git_config(git_merge_config, NULL);
1110
1111 if (branch_mergeoptions)
1112 parse_branch_merge_options(branch_mergeoptions);
1113 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1114 builtin_merge_usage, 0);
1115 if (shortlog_len < 0)
1116 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1117
1118 if (verbosity < 0 && show_progress == -1)
1119 show_progress = 0;
1120
1121 if (abort_current_merge) {
1122 int nargc = 2;
1123 const char *nargv[] = {"reset", "--merge", NULL};
1124
1125 if (!file_exists(git_path("MERGE_HEAD")))
1126 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1127
1128 /* Invoke 'git reset --merge' */
1129 ret = cmd_reset(nargc, nargv, prefix);
1130 goto done;
1131 }
1132
1133 if (read_cache_unmerged())
1134 die_resolve_conflict("merge");
1135
1136 if (file_exists(git_path("MERGE_HEAD"))) {
1137 /*
1138 * There is no unmerged entry, don't advise 'git
1139 * add/rm <file>', just 'git commit'.
1140 */
1141 if (advice_resolve_conflict)
1142 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1143 "Please, commit your changes before you can merge."));
1144 else
1145 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1146 }
1147 if (file_exists(git_path("CHERRY_PICK_HEAD"))) {
1148 if (advice_resolve_conflict)
1149 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1150 "Please, commit your changes before you can merge."));
1151 else
1152 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1153 }
1154 resolve_undo_clear();
1155
1156 if (verbosity < 0)
1157 show_diffstat = 0;
1158
1159 if (squash) {
1160 if (!allow_fast_forward)
1161 die(_("You cannot combine --squash with --no-ff."));
1162 option_commit = 0;
1163 }
1164
1165 if (!allow_fast_forward && fast_forward_only)
1166 die(_("You cannot combine --no-ff with --ff-only."));
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 * committish 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 (!allow_fast_forward)
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, 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 free(signature_check.gpg_output);
1279 free(signature_check.gpg_status);
1280 free(signature_check.signer);
1281 free(signature_check.key);
1282 }
1283 }
1284
1285 strbuf_addstr(&buf, "merge");
1286 for (p = remoteheads; p; p = p->next)
1287 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1288 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1289 strbuf_reset(&buf);
1290
1291 for (p = remoteheads; p; p = p->next) {
1292 struct commit *commit = p->item;
1293 strbuf_addf(&buf, "GITHEAD_%s",
1294 sha1_to_hex(commit->object.sha1));
1295 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1296 strbuf_reset(&buf);
1297 if (!fast_forward_only &&
1298 merge_remote_util(commit) &&
1299 merge_remote_util(commit)->obj &&
1300 merge_remote_util(commit)->obj->type == OBJ_TAG)
1301 allow_fast_forward = 0;
1302 }
1303
1304 if (option_edit < 0)
1305 option_edit = default_edit_option();
1306
1307 if (!use_strategies) {
1308 if (!remoteheads)
1309 ; /* already up-to-date */
1310 else if (!remoteheads->next)
1311 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1312 else
1313 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1314 }
1315
1316 for (i = 0; i < use_strategies_nr; i++) {
1317 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1318 allow_fast_forward = 0;
1319 if (use_strategies[i]->attr & NO_TRIVIAL)
1320 allow_trivial = 0;
1321 }
1322
1323 if (!remoteheads)
1324 ; /* already up-to-date */
1325 else if (!remoteheads->next)
1326 common = get_merge_bases(head_commit, remoteheads->item, 1);
1327 else {
1328 struct commit_list *list = remoteheads;
1329 commit_list_insert(head_commit, &list);
1330 common = get_octopus_merge_bases(list);
1331 free(list);
1332 }
1333
1334 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.sha1,
1335 NULL, 0, DIE_ON_ERR);
1336
1337 if (remoteheads && !common)
1338 ; /* No common ancestors found. We need a real merge. */
1339 else if (!remoteheads ||
1340 (!remoteheads->next && !common->next &&
1341 common->item == remoteheads->item)) {
1342 /*
1343 * If head can reach all the merge then we are up to date.
1344 * but first the most common case of merging one remote.
1345 */
1346 finish_up_to_date("Already up-to-date.");
1347 goto done;
1348 } else if (allow_fast_forward && !remoteheads->next &&
1349 !common->next &&
1350 !hashcmp(common->item->object.sha1, head_commit->object.sha1)) {
1351 /* Again the most common case of merging one remote. */
1352 struct strbuf msg = STRBUF_INIT;
1353 struct commit *commit;
1354 char hex[41];
1355
1356 strcpy(hex, find_unique_abbrev(head_commit->object.sha1, DEFAULT_ABBREV));
1357
1358 if (verbosity >= 0)
1359 printf(_("Updating %s..%s\n"),
1360 hex,
1361 find_unique_abbrev(remoteheads->item->object.sha1,
1362 DEFAULT_ABBREV));
1363 strbuf_addstr(&msg, "Fast-forward");
1364 if (have_message)
1365 strbuf_addstr(&msg,
1366 " (no commit created; -m option ignored)");
1367 commit = remoteheads->item;
1368 if (!commit) {
1369 ret = 1;
1370 goto done;
1371 }
1372
1373 if (checkout_fast_forward(head_commit->object.sha1,
1374 commit->object.sha1,
1375 overwrite_ignore)) {
1376 ret = 1;
1377 goto done;
1378 }
1379
1380 finish(head_commit, remoteheads, commit->object.sha1, msg.buf);
1381 drop_save();
1382 goto done;
1383 } else if (!remoteheads->next && common->next)
1384 ;
1385 /*
1386 * We are not doing octopus and not fast-forward. Need
1387 * a real merge.
1388 */
1389 else if (!remoteheads->next && !common->next && option_commit) {
1390 /*
1391 * We are not doing octopus, not fast-forward, and have
1392 * only one common.
1393 */
1394 refresh_cache(REFRESH_QUIET);
1395 if (allow_trivial && !fast_forward_only) {
1396 /* See if it is really trivial. */
1397 git_committer_info(IDENT_STRICT);
1398 printf(_("Trying really trivial in-index merge...\n"));
1399 if (!read_tree_trivial(common->item->object.sha1,
1400 head_commit->object.sha1,
1401 remoteheads->item->object.sha1)) {
1402 ret = merge_trivial(head_commit, remoteheads);
1403 goto done;
1404 }
1405 printf(_("Nope.\n"));
1406 }
1407 } else {
1408 /*
1409 * An octopus. If we can reach all the remote we are up
1410 * to date.
1411 */
1412 int up_to_date = 1;
1413 struct commit_list *j;
1414
1415 for (j = remoteheads; j; j = j->next) {
1416 struct commit_list *common_one;
1417
1418 /*
1419 * Here we *have* to calculate the individual
1420 * merge_bases again, otherwise "git merge HEAD^
1421 * HEAD^^" would be missed.
1422 */
1423 common_one = get_merge_bases(head_commit, j->item, 1);
1424 if (hashcmp(common_one->item->object.sha1,
1425 j->item->object.sha1)) {
1426 up_to_date = 0;
1427 break;
1428 }
1429 }
1430 if (up_to_date) {
1431 finish_up_to_date("Already up-to-date. Yeeah!");
1432 goto done;
1433 }
1434 }
1435
1436 if (fast_forward_only)
1437 die(_("Not possible to fast-forward, aborting."));
1438
1439 /* We are going to make a new commit. */
1440 git_committer_info(IDENT_STRICT);
1441
1442 /*
1443 * At this point, we need a real merge. No matter what strategy
1444 * we use, it would operate on the index, possibly affecting the
1445 * working tree, and when resolved cleanly, have the desired
1446 * tree in the index -- this means that the index must be in
1447 * sync with the head commit. The strategies are responsible
1448 * to ensure this.
1449 */
1450 if (use_strategies_nr == 1 ||
1451 /*
1452 * Stash away the local changes so that we can try more than one.
1453 */
1454 save_state(stash))
1455 hashcpy(stash, null_sha1);
1456
1457 for (i = 0; i < use_strategies_nr; i++) {
1458 int ret;
1459 if (i) {
1460 printf(_("Rewinding the tree to pristine...\n"));
1461 restore_state(head_commit->object.sha1, stash);
1462 }
1463 if (use_strategies_nr != 1)
1464 printf(_("Trying merge strategy %s...\n"),
1465 use_strategies[i]->name);
1466 /*
1467 * Remember which strategy left the state in the working
1468 * tree.
1469 */
1470 wt_strategy = use_strategies[i]->name;
1471
1472 ret = try_merge_strategy(use_strategies[i]->name,
1473 common, remoteheads,
1474 head_commit, head_arg);
1475 if (!option_commit && !ret) {
1476 merge_was_ok = 1;
1477 /*
1478 * This is necessary here just to avoid writing
1479 * the tree, but later we will *not* exit with
1480 * status code 1 because merge_was_ok is set.
1481 */
1482 ret = 1;
1483 }
1484
1485 if (ret) {
1486 /*
1487 * The backend exits with 1 when conflicts are
1488 * left to be resolved, with 2 when it does not
1489 * handle the given merge at all.
1490 */
1491 if (ret == 1) {
1492 int cnt = evaluate_result();
1493
1494 if (best_cnt <= 0 || cnt <= best_cnt) {
1495 best_strategy = use_strategies[i]->name;
1496 best_cnt = cnt;
1497 }
1498 }
1499 if (merge_was_ok)
1500 break;
1501 else
1502 continue;
1503 }
1504
1505 /* Automerge succeeded. */
1506 write_tree_trivial(result_tree);
1507 automerge_was_ok = 1;
1508 break;
1509 }
1510
1511 /*
1512 * If we have a resulting tree, that means the strategy module
1513 * auto resolved the merge cleanly.
1514 */
1515 if (automerge_was_ok) {
1516 ret = finish_automerge(head_commit, head_subsumed,
1517 common, remoteheads,
1518 result_tree, wt_strategy);
1519 goto done;
1520 }
1521
1522 /*
1523 * Pick the result from the best strategy and have the user fix
1524 * it up.
1525 */
1526 if (!best_strategy) {
1527 restore_state(head_commit->object.sha1, stash);
1528 if (use_strategies_nr > 1)
1529 fprintf(stderr,
1530 _("No merge strategy handled the merge.\n"));
1531 else
1532 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1533 use_strategies[0]->name);
1534 ret = 2;
1535 goto done;
1536 } else if (best_strategy == wt_strategy)
1537 ; /* We already have its result in the working tree. */
1538 else {
1539 printf(_("Rewinding the tree to pristine...\n"));
1540 restore_state(head_commit->object.sha1, stash);
1541 printf(_("Using the %s to prepare resolving by hand.\n"),
1542 best_strategy);
1543 try_merge_strategy(best_strategy, common, remoteheads,
1544 head_commit, head_arg);
1545 }
1546
1547 if (squash)
1548 finish(head_commit, remoteheads, NULL, NULL);
1549 else
1550 write_merge_state(remoteheads);
1551
1552 if (merge_was_ok)
1553 fprintf(stderr, _("Automatic merge went well; "
1554 "stopped before committing as requested\n"));
1555 else
1556 ret = suggest_conflicts(option_renormalize);
1557
1558 done:
1559 free(branch_to_free);
1560 return ret;
1561 }