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[git/debian.git] / builtin / merge.c
bloba96d4fb501bf1441b52a313313b8c04f3187e4d9
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 #include "sequencer.h"
33 #include "string-list.h"
34
35 #define DEFAULT_TWOHEAD (1<<0)
36 #define DEFAULT_OCTOPUS (1<<1)
37 #define NO_FAST_FORWARD (1<<2)
38 #define NO_TRIVIAL (1<<3)
39
40 struct strategy {
41 const char *name;
42 unsigned attr;
43 };
44
45 static const char * const builtin_merge_usage[] = {
46 N_("git merge [<options>] [<commit>...]"),
47 N_("git merge [<options>] <msg> HEAD <commit>"),
48 N_("git merge --abort"),
49 N_("git merge --continue"),
50 NULL
51 };
52
53 static int show_diffstat = 1, shortlog_len = -1, squash;
54 static int option_commit = 1;
55 static int option_edit = -1;
56 static int allow_trivial = 1, have_message, verify_signatures;
57 static int overwrite_ignore = 1;
58 static struct strbuf merge_msg = STRBUF_INIT;
59 static struct strategy **use_strategies;
60 static size_t use_strategies_nr, use_strategies_alloc;
61 static const char **xopts;
62 static size_t xopts_nr, xopts_alloc;
63 static const char *branch;
64 static char *branch_mergeoptions;
65 static int option_renormalize;
66 static int verbosity;
67 static int allow_rerere_auto;
68 static int abort_current_merge;
69 static int continue_current_merge;
70 static int allow_unrelated_histories;
71 static int show_progress = -1;
72 static int default_to_upstream = 1;
73 static const char *sign_commit;
74
75 static struct strategy all_strategy[] = {
76 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
77 { "octopus", DEFAULT_OCTOPUS },
78 { "resolve", 0 },
79 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
80 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
81 };
82
83 static const char *pull_twohead, *pull_octopus;
84
85 enum ff_type {
86 FF_NO,
87 FF_ALLOW,
88 FF_ONLY
89 };
90
91 static enum ff_type fast_forward = FF_ALLOW;
92
93 static int option_parse_message(const struct option *opt,
94 const char *arg, int unset)
95 {
96 struct strbuf *buf = opt->value;
97
98 if (unset)
99 strbuf_setlen(buf, 0);
100 else if (arg) {
101 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
102 have_message = 1;
103 } else
104 return error(_("switch `m' requires a value"));
105 return 0;
106 }
107
108 static struct strategy *get_strategy(const char *name)
109 {
110 int i;
111 struct strategy *ret;
112 static struct cmdnames main_cmds, other_cmds;
113 static int loaded;
114
115 if (!name)
116 return NULL;
117
118 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
119 if (!strcmp(name, all_strategy[i].name))
120 return &all_strategy[i];
121
122 if (!loaded) {
123 struct cmdnames not_strategies;
124 loaded = 1;
125
126 memset(&not_strategies, 0, sizeof(struct cmdnames));
127 load_command_list("git-merge-", &main_cmds, &other_cmds);
128 for (i = 0; i < main_cmds.cnt; i++) {
129 int j, found = 0;
130 struct cmdname *ent = main_cmds.names[i];
131 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
132 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
133 && !all_strategy[j].name[ent->len])
134 found = 1;
135 if (!found)
136 add_cmdname(&not_strategies, ent->name, ent->len);
137 }
138 exclude_cmds(&main_cmds, &not_strategies);
139 }
140 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
141 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
142 fprintf(stderr, _("Available strategies are:"));
143 for (i = 0; i < main_cmds.cnt; i++)
144 fprintf(stderr, " %s", main_cmds.names[i]->name);
145 fprintf(stderr, ".\n");
146 if (other_cmds.cnt) {
147 fprintf(stderr, _("Available custom strategies are:"));
148 for (i = 0; i < other_cmds.cnt; i++)
149 fprintf(stderr, " %s", other_cmds.names[i]->name);
150 fprintf(stderr, ".\n");
151 }
152 exit(1);
153 }
154
155 ret = xcalloc(1, sizeof(struct strategy));
156 ret->name = xstrdup(name);
157 ret->attr = NO_TRIVIAL;
158 return ret;
159 }
160
161 static void append_strategy(struct strategy *s)
162 {
163 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
164 use_strategies[use_strategies_nr++] = s;
165 }
166
167 static int option_parse_strategy(const struct option *opt,
168 const char *name, int unset)
169 {
170 if (unset)
171 return 0;
172
173 append_strategy(get_strategy(name));
174 return 0;
175 }
176
177 static int option_parse_x(const struct option *opt,
178 const char *arg, int unset)
179 {
180 if (unset)
181 return 0;
182
183 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
184 xopts[xopts_nr++] = xstrdup(arg);
185 return 0;
186 }
187
188 static int option_parse_n(const struct option *opt,
189 const char *arg, int unset)
190 {
191 show_diffstat = unset;
192 return 0;
193 }
194
195 static struct option builtin_merge_options[] = {
196 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
197 N_("do not show a diffstat at the end of the merge"),
198 PARSE_OPT_NOARG, option_parse_n },
199 OPT_BOOL(0, "stat", &show_diffstat,
200 N_("show a diffstat at the end of the merge")),
201 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
202 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
203 N_("add (at most <n>) entries from shortlog to merge commit message"),
204 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
205 OPT_BOOL(0, "squash", &squash,
206 N_("create a single commit instead of doing a merge")),
207 OPT_BOOL(0, "commit", &option_commit,
208 N_("perform a commit if the merge succeeds (default)")),
209 OPT_BOOL('e', "edit", &option_edit,
210 N_("edit message before committing")),
211 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
212 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
213 N_("abort if fast-forward is not possible"),
214 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
215 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
216 OPT_BOOL(0, "verify-signatures", &verify_signatures,
217 N_("verify that the named commit has a valid GPG signature")),
218 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
219 N_("merge strategy to use"), option_parse_strategy),
220 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
221 N_("option for selected merge strategy"), option_parse_x),
222 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
223 N_("merge commit message (for a non-fast-forward merge)"),
224 option_parse_message),
225 OPT__VERBOSITY(&verbosity),
226 OPT_BOOL(0, "abort", &abort_current_merge,
227 N_("abort the current in-progress merge")),
228 OPT_BOOL(0, "continue", &continue_current_merge,
229 N_("continue the current in-progress merge")),
230 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
231 N_("allow merging unrelated histories")),
232 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
233 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
234 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
235 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
236 OPT_END()
237 };
238
239 /* Cleans up metadata that is uninteresting after a succeeded merge. */
240 static void drop_save(void)
241 {
242 unlink(git_path_merge_head());
243 unlink(git_path_merge_msg());
244 unlink(git_path_merge_mode());
245 }
246
247 static int save_state(unsigned char *stash)
248 {
249 int len;
250 struct child_process cp = CHILD_PROCESS_INIT;
251 struct strbuf buffer = STRBUF_INIT;
252 const char *argv[] = {"stash", "create", NULL};
253
254 cp.argv = argv;
255 cp.out = -1;
256 cp.git_cmd = 1;
257
258 if (start_command(&cp))
259 die(_("could not run stash."));
260 len = strbuf_read(&buffer, cp.out, 1024);
261 close(cp.out);
262
263 if (finish_command(&cp) || len < 0)
264 die(_("stash failed"));
265 else if (!len) /* no changes */
266 return -1;
267 strbuf_setlen(&buffer, buffer.len-1);
268 if (get_sha1(buffer.buf, stash))
269 die(_("not a valid object: %s"), buffer.buf);
270 return 0;
271 }
272
273 static void read_empty(unsigned const char *sha1, int verbose)
274 {
275 int i = 0;
276 const char *args[7];
277
278 args[i++] = "read-tree";
279 if (verbose)
280 args[i++] = "-v";
281 args[i++] = "-m";
282 args[i++] = "-u";
283 args[i++] = EMPTY_TREE_SHA1_HEX;
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 reset_hard(unsigned const char *sha1, int verbose)
292 {
293 int i = 0;
294 const char *args[6];
295
296 args[i++] = "read-tree";
297 if (verbose)
298 args[i++] = "-v";
299 args[i++] = "--reset";
300 args[i++] = "-u";
301 args[i++] = sha1_to_hex(sha1);
302 args[i] = NULL;
303
304 if (run_command_v_opt(args, RUN_GIT_CMD))
305 die(_("read-tree failed"));
306 }
307
308 static void restore_state(const unsigned char *head,
309 const unsigned char *stash)
310 {
311 struct strbuf sb = STRBUF_INIT;
312 const char *args[] = { "stash", "apply", NULL, NULL };
313
314 if (is_null_sha1(stash))
315 return;
316
317 reset_hard(head, 1);
318
319 args[2] = sha1_to_hex(stash);
320
321 /*
322 * It is OK to ignore error here, for example when there was
323 * nothing to restore.
324 */
325 run_command_v_opt(args, RUN_GIT_CMD);
326
327 strbuf_release(&sb);
328 refresh_cache(REFRESH_QUIET);
329 }
330
331 /* This is called when no merge was necessary. */
332 static void finish_up_to_date(const char *msg)
333 {
334 if (verbosity >= 0)
335 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
336 drop_save();
337 }
338
339 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
340 {
341 struct rev_info rev;
342 struct strbuf out = STRBUF_INIT;
343 struct commit_list *j;
344 struct pretty_print_context ctx = {0};
345
346 printf(_("Squash commit -- not updating HEAD\n"));
347
348 init_revisions(&rev, NULL);
349 rev.ignore_merges = 1;
350 rev.commit_format = CMIT_FMT_MEDIUM;
351
352 commit->object.flags |= UNINTERESTING;
353 add_pending_object(&rev, &commit->object, NULL);
354
355 for (j = remoteheads; j; j = j->next)
356 add_pending_object(&rev, &j->item->object, NULL);
357
358 setup_revisions(0, NULL, &rev, NULL);
359 if (prepare_revision_walk(&rev))
360 die(_("revision walk setup failed"));
361
362 ctx.abbrev = rev.abbrev;
363 ctx.date_mode = rev.date_mode;
364 ctx.fmt = rev.commit_format;
365
366 strbuf_addstr(&out, "Squashed commit of the following:\n");
367 while ((commit = get_revision(&rev)) != NULL) {
368 strbuf_addch(&out, '\n');
369 strbuf_addf(&out, "commit %s\n",
370 oid_to_hex(&commit->object.oid));
371 pretty_print_commit(&ctx, commit, &out);
372 }
373 write_file_buf(git_path_squash_msg(), out.buf, out.len);
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.oid.hash;
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 close_all_packs();
407 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
408 }
409 }
410 if (new_head && show_diffstat) {
411 struct diff_options opts;
412 diff_setup(&opts);
413 opts.stat_width = -1; /* use full terminal width */
414 opts.stat_graph_width = -1; /* respect statGraphWidth config */
415 opts.output_format |=
416 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
417 opts.detect_rename = DIFF_DETECT_RENAME;
418 diff_setup_done(&opts);
419 diff_tree_sha1(head, new_head, "", &opts);
420 diffcore_std(&opts);
421 diff_flush(&opts);
422 }
423
424 /* Run a post-merge hook */
425 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
426
427 strbuf_release(&reflog_message);
428 }
429
430 /* Get the name for the merge commit's message. */
431 static void merge_name(const char *remote, struct strbuf *msg)
432 {
433 struct commit *remote_head;
434 unsigned char branch_head[20];
435 struct strbuf buf = STRBUF_INIT;
436 struct strbuf bname = STRBUF_INIT;
437 const char *ptr;
438 char *found_ref;
439 int len, early;
440
441 strbuf_branchname(&bname, remote);
442 remote = bname.buf;
443
444 memset(branch_head, 0, sizeof(branch_head));
445 remote_head = get_merge_parent(remote);
446 if (!remote_head)
447 die(_("'%s' does not point to a commit"), remote);
448
449 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
450 if (starts_with(found_ref, "refs/heads/")) {
451 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
452 sha1_to_hex(branch_head), remote);
453 goto cleanup;
454 }
455 if (starts_with(found_ref, "refs/tags/")) {
456 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
457 sha1_to_hex(branch_head), remote);
458 goto cleanup;
459 }
460 if (starts_with(found_ref, "refs/remotes/")) {
461 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
462 sha1_to_hex(branch_head), remote);
463 goto cleanup;
464 }
465 }
466
467 /* See if remote matches <name>^^^.. or <name>~<number> */
468 for (len = 0, ptr = remote + strlen(remote);
469 remote < ptr && ptr[-1] == '^';
470 ptr--)
471 len++;
472 if (len)
473 early = 1;
474 else {
475 early = 0;
476 ptr = strrchr(remote, '~');
477 if (ptr) {
478 int seen_nonzero = 0;
479
480 len++; /* count ~ */
481 while (*++ptr && isdigit(*ptr)) {
482 seen_nonzero |= (*ptr != '0');
483 len++;
484 }
485 if (*ptr)
486 len = 0; /* not ...~<number> */
487 else if (seen_nonzero)
488 early = 1;
489 else if (len == 1)
490 early = 1; /* "name~" is "name~1"! */
491 }
492 }
493 if (len) {
494 struct strbuf truname = STRBUF_INIT;
495 strbuf_addf(&truname, "refs/heads/%s", 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 oid_to_hex(&remote_head->object.oid),
501 truname.buf + 11,
502 (early ? " (early part)" : ""));
503 strbuf_release(&truname);
504 goto cleanup;
505 }
506 strbuf_release(&truname);
507 }
508
509 if (remote_head->util) {
510 struct merge_remote_desc *desc;
511 desc = merge_remote_util(remote_head);
512 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
513 strbuf_addf(msg, "%s\t\t%s '%s'\n",
514 oid_to_hex(&desc->obj->oid),
515 typename(desc->obj->type),
516 remote);
517 goto cleanup;
518 }
519 }
520
521 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
522 oid_to_hex(&remote_head->object.oid), remote);
523 cleanup:
524 strbuf_release(&buf);
525 strbuf_release(&bname);
526 }
527
528 static void parse_branch_merge_options(char *bmo)
529 {
530 const char **argv;
531 int argc;
532
533 if (!bmo)
534 return;
535 argc = split_cmdline(bmo, &argv);
536 if (argc < 0)
537 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
538 split_cmdline_strerror(argc));
539 REALLOC_ARRAY(argv, argc + 2);
540 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
541 argc++;
542 argv[0] = "branch.*.mergeoptions";
543 parse_options(argc, argv, NULL, builtin_merge_options,
544 builtin_merge_usage, 0);
545 free(argv);
546 }
547
548 static int git_merge_config(const char *k, const char *v, void *cb)
549 {
550 int status;
551
552 if (branch && starts_with(k, "branch.") &&
553 starts_with(k + 7, branch) &&
554 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
555 free(branch_mergeoptions);
556 branch_mergeoptions = xstrdup(v);
557 return 0;
558 }
559
560 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
561 show_diffstat = git_config_bool(k, v);
562 else if (!strcmp(k, "pull.twohead"))
563 return git_config_string(&pull_twohead, k, v);
564 else if (!strcmp(k, "pull.octopus"))
565 return git_config_string(&pull_octopus, k, v);
566 else if (!strcmp(k, "merge.renormalize"))
567 option_renormalize = git_config_bool(k, v);
568 else if (!strcmp(k, "merge.ff")) {
569 int boolval = git_config_maybe_bool(k, v);
570 if (0 <= boolval) {
571 fast_forward = boolval ? FF_ALLOW : FF_NO;
572 } else if (v && !strcmp(v, "only")) {
573 fast_forward = FF_ONLY;
574 } /* do not barf on values from future versions of git */
575 return 0;
576 } else if (!strcmp(k, "merge.defaulttoupstream")) {
577 default_to_upstream = git_config_bool(k, v);
578 return 0;
579 } else if (!strcmp(k, "commit.gpgsign")) {
580 sign_commit = git_config_bool(k, v) ? "" : NULL;
581 return 0;
582 }
583
584 status = fmt_merge_msg_config(k, v, cb);
585 if (status)
586 return status;
587 status = git_gpg_config(k, v, NULL);
588 if (status)
589 return status;
590 return git_diff_ui_config(k, v, cb);
591 }
592
593 static int read_tree_trivial(unsigned char *common, unsigned char *head,
594 unsigned char *one)
595 {
596 int i, nr_trees = 0;
597 struct tree *trees[MAX_UNPACK_TREES];
598 struct tree_desc t[MAX_UNPACK_TREES];
599 struct unpack_trees_options opts;
600
601 memset(&opts, 0, sizeof(opts));
602 opts.head_idx = 2;
603 opts.src_index = &the_index;
604 opts.dst_index = &the_index;
605 opts.update = 1;
606 opts.verbose_update = 1;
607 opts.trivial_merges_only = 1;
608 opts.merge = 1;
609 trees[nr_trees] = parse_tree_indirect(common);
610 if (!trees[nr_trees++])
611 return -1;
612 trees[nr_trees] = parse_tree_indirect(head);
613 if (!trees[nr_trees++])
614 return -1;
615 trees[nr_trees] = parse_tree_indirect(one);
616 if (!trees[nr_trees++])
617 return -1;
618 opts.fn = threeway_merge;
619 cache_tree_free(&active_cache_tree);
620 for (i = 0; i < nr_trees; i++) {
621 parse_tree(trees[i]);
622 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
623 }
624 if (unpack_trees(nr_trees, t, &opts))
625 return -1;
626 return 0;
627 }
628
629 static void write_tree_trivial(unsigned char *sha1)
630 {
631 if (write_cache_as_tree(sha1, 0, NULL))
632 die(_("git write-tree failed to write a tree"));
633 }
634
635 static int try_merge_strategy(const char *strategy, struct commit_list *common,
636 struct commit_list *remoteheads,
637 struct commit *head, const char *head_arg)
638 {
639 static struct lock_file lock;
640
641 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
642 refresh_cache(REFRESH_QUIET);
643 if (active_cache_changed &&
644 write_locked_index(&the_index, &lock, COMMIT_LOCK))
645 return error(_("Unable to write index."));
646 rollback_lock_file(&lock);
647
648 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
649 int clean, x;
650 struct commit *result;
651 struct commit_list *reversed = NULL;
652 struct merge_options o;
653 struct commit_list *j;
654
655 if (remoteheads->next) {
656 error(_("Not handling anything other than two heads merge."));
657 return 2;
658 }
659
660 init_merge_options(&o);
661 if (!strcmp(strategy, "subtree"))
662 o.subtree_shift = "";
663
664 o.renormalize = option_renormalize;
665 o.show_rename_progress =
666 show_progress == -1 ? isatty(2) : show_progress;
667
668 for (x = 0; x < xopts_nr; x++)
669 if (parse_merge_opt(&o, xopts[x]))
670 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
671
672 o.branch1 = head_arg;
673 o.branch2 = merge_remote_util(remoteheads->item)->name;
674
675 for (j = common; j; j = j->next)
676 commit_list_insert(j->item, &reversed);
677
678 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
679 clean = merge_recursive(&o, head,
680 remoteheads->item, reversed, &result);
681 if (clean < 0)
682 exit(128);
683 if (active_cache_changed &&
684 write_locked_index(&the_index, &lock, COMMIT_LOCK))
685 die (_("unable to write %s"), get_index_file());
686 rollback_lock_file(&lock);
687 return clean ? 0 : 1;
688 } else {
689 return try_merge_command(strategy, xopts_nr, xopts,
690 common, head_arg, remoteheads);
691 }
692 }
693
694 static void count_diff_files(struct diff_queue_struct *q,
695 struct diff_options *opt, void *data)
696 {
697 int *count = data;
698
699 (*count) += q->nr;
700 }
701
702 static int count_unmerged_entries(void)
703 {
704 int i, ret = 0;
705
706 for (i = 0; i < active_nr; i++)
707 if (ce_stage(active_cache[i]))
708 ret++;
709
710 return ret;
711 }
712
713 static void add_strategies(const char *string, unsigned attr)
714 {
715 int i;
716
717 if (string) {
718 struct string_list list = STRING_LIST_INIT_DUP;
719 struct string_list_item *item;
720 string_list_split(&list, string, ' ', -1);
721 for_each_string_list_item(item, &list)
722 append_strategy(get_strategy(item->string));
723 string_list_clear(&list, 0);
724 return;
725 }
726 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
727 if (all_strategy[i].attr & attr)
728 append_strategy(&all_strategy[i]);
729
730 }
731
732 static void read_merge_msg(struct strbuf *msg)
733 {
734 const char *filename = git_path_merge_msg();
735 strbuf_reset(msg);
736 if (strbuf_read_file(msg, filename, 0) < 0)
737 die_errno(_("Could not read from '%s'"), filename);
738 }
739
740 static void write_merge_state(struct commit_list *);
741 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
742 {
743 if (err_msg)
744 error("%s", err_msg);
745 fprintf(stderr,
746 _("Not committing merge; use 'git commit' to complete the merge.\n"));
747 write_merge_state(remoteheads);
748 exit(1);
749 }
750
751 static const char merge_editor_comment[] =
752 N_("Please enter a commit message to explain why this merge is necessary,\n"
753 "especially if it merges an updated upstream into a topic branch.\n"
754 "\n"
755 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
756 "the commit.\n");
757
758 static void prepare_to_commit(struct commit_list *remoteheads)
759 {
760 struct strbuf msg = STRBUF_INIT;
761 strbuf_addbuf(&msg, &merge_msg);
762 strbuf_addch(&msg, '\n');
763 if (0 < option_edit)
764 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
765 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
766 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
767 git_path_merge_msg(), "merge", NULL))
768 abort_commit(remoteheads, NULL);
769 if (0 < option_edit) {
770 if (launch_editor(git_path_merge_msg(), NULL, NULL))
771 abort_commit(remoteheads, NULL);
772 }
773 read_merge_msg(&msg);
774 strbuf_stripspace(&msg, 0 < option_edit);
775 if (!msg.len)
776 abort_commit(remoteheads, _("Empty commit message."));
777 strbuf_release(&merge_msg);
778 strbuf_addbuf(&merge_msg, &msg);
779 strbuf_release(&msg);
780 }
781
782 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
783 {
784 unsigned char result_tree[20], result_commit[20];
785 struct commit_list *parents, **pptr = &parents;
786 static struct lock_file lock;
787
788 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
789 refresh_cache(REFRESH_QUIET);
790 if (active_cache_changed &&
791 write_locked_index(&the_index, &lock, COMMIT_LOCK))
792 return error(_("Unable to write index."));
793 rollback_lock_file(&lock);
794
795 write_tree_trivial(result_tree);
796 printf(_("Wonderful.\n"));
797 pptr = commit_list_append(head, pptr);
798 pptr = commit_list_append(remoteheads->item, pptr);
799 prepare_to_commit(remoteheads);
800 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
801 result_commit, NULL, sign_commit))
802 die(_("failed to write commit object"));
803 finish(head, remoteheads, result_commit, "In-index merge");
804 drop_save();
805 return 0;
806 }
807
808 static int finish_automerge(struct commit *head,
809 int head_subsumed,
810 struct commit_list *common,
811 struct commit_list *remoteheads,
812 unsigned char *result_tree,
813 const char *wt_strategy)
814 {
815 struct commit_list *parents = NULL;
816 struct strbuf buf = STRBUF_INIT;
817 unsigned char result_commit[20];
818
819 free_commit_list(common);
820 parents = remoteheads;
821 if (!head_subsumed || fast_forward == FF_NO)
822 commit_list_insert(head, &parents);
823 strbuf_addch(&merge_msg, '\n');
824 prepare_to_commit(remoteheads);
825 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
826 result_commit, NULL, sign_commit))
827 die(_("failed to write commit object"));
828 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
829 finish(head, remoteheads, result_commit, buf.buf);
830 strbuf_release(&buf);
831 drop_save();
832 return 0;
833 }
834
835 static int suggest_conflicts(void)
836 {
837 const char *filename;
838 FILE *fp;
839 struct strbuf msgbuf = STRBUF_INIT;
840
841 filename = git_path_merge_msg();
842 fp = fopen(filename, "a");
843 if (!fp)
844 die_errno(_("Could not open '%s' for writing"), filename);
845
846 append_conflicts_hint(&msgbuf);
847 fputs(msgbuf.buf, fp);
848 strbuf_release(&msgbuf);
849 fclose(fp);
850 rerere(allow_rerere_auto);
851 printf(_("Automatic merge failed; "
852 "fix conflicts and then commit the result.\n"));
853 return 1;
854 }
855
856 static struct commit *is_old_style_invocation(int argc, const char **argv,
857 const unsigned char *head)
858 {
859 struct commit *second_token = NULL;
860 if (argc > 2) {
861 unsigned char second_sha1[20];
862
863 if (get_sha1(argv[1], second_sha1))
864 return NULL;
865 second_token = lookup_commit_reference_gently(second_sha1, 0);
866 if (!second_token)
867 die(_("'%s' is not a commit"), argv[1]);
868 if (hashcmp(second_token->object.oid.hash, head))
869 return NULL;
870 }
871 return second_token;
872 }
873
874 static int evaluate_result(void)
875 {
876 int cnt = 0;
877 struct rev_info rev;
878
879 /* Check how many files differ. */
880 init_revisions(&rev, "");
881 setup_revisions(0, NULL, &rev, NULL);
882 rev.diffopt.output_format |=
883 DIFF_FORMAT_CALLBACK;
884 rev.diffopt.format_callback = count_diff_files;
885 rev.diffopt.format_callback_data = &cnt;
886 run_diff_files(&rev, 0);
887
888 /*
889 * Check how many unmerged entries are
890 * there.
891 */
892 cnt += count_unmerged_entries();
893
894 return cnt;
895 }
896
897 /*
898 * Pretend as if the user told us to merge with the remote-tracking
899 * branch we have for the upstream of the current branch
900 */
901 static int setup_with_upstream(const char ***argv)
902 {
903 struct branch *branch = branch_get(NULL);
904 int i;
905 const char **args;
906
907 if (!branch)
908 die(_("No current branch."));
909 if (!branch->remote_name)
910 die(_("No remote for the current branch."));
911 if (!branch->merge_nr)
912 die(_("No default upstream defined for the current branch."));
913
914 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
915 for (i = 0; i < branch->merge_nr; i++) {
916 if (!branch->merge[i]->dst)
917 die(_("No remote-tracking branch for %s from %s"),
918 branch->merge[i]->src, branch->remote_name);
919 args[i] = branch->merge[i]->dst;
920 }
921 args[i] = NULL;
922 *argv = args;
923 return i;
924 }
925
926 static void write_merge_state(struct commit_list *remoteheads)
927 {
928 struct commit_list *j;
929 struct strbuf buf = STRBUF_INIT;
930
931 for (j = remoteheads; j; j = j->next) {
932 struct object_id *oid;
933 struct commit *c = j->item;
934 if (c->util && merge_remote_util(c)->obj) {
935 oid = &merge_remote_util(c)->obj->oid;
936 } else {
937 oid = &c->object.oid;
938 }
939 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
940 }
941 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
942 strbuf_addch(&merge_msg, '\n');
943 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
944
945 strbuf_reset(&buf);
946 if (fast_forward == FF_NO)
947 strbuf_addstr(&buf, "no-ff");
948 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
949 }
950
951 static int default_edit_option(void)
952 {
953 static const char name[] = "GIT_MERGE_AUTOEDIT";
954 const char *e = getenv(name);
955 struct stat st_stdin, st_stdout;
956
957 if (have_message)
958 /* an explicit -m msg without --[no-]edit */
959 return 0;
960
961 if (e) {
962 int v = git_config_maybe_bool(name, e);
963 if (v < 0)
964 die(_("Bad value '%s' in environment '%s'"), e, name);
965 return v;
966 }
967
968 /* Use editor if stdin and stdout are the same and is a tty */
969 return (!fstat(0, &st_stdin) &&
970 !fstat(1, &st_stdout) &&
971 isatty(0) && isatty(1) &&
972 st_stdin.st_dev == st_stdout.st_dev &&
973 st_stdin.st_ino == st_stdout.st_ino &&
974 st_stdin.st_mode == st_stdout.st_mode);
975 }
976
977 static struct commit_list *reduce_parents(struct commit *head_commit,
978 int *head_subsumed,
979 struct commit_list *remoteheads)
980 {
981 struct commit_list *parents, **remotes;
982
983 /*
984 * Is the current HEAD reachable from another commit being
985 * merged? If so we do not want to record it as a parent of
986 * the resulting merge, unless --no-ff is given. We will flip
987 * this variable to 0 when we find HEAD among the independent
988 * tips being merged.
989 */
990 *head_subsumed = 1;
991
992 /* Find what parents to record by checking independent ones. */
993 parents = reduce_heads(remoteheads);
994
995 remoteheads = NULL;
996 remotes = &remoteheads;
997 while (parents) {
998 struct commit *commit = pop_commit(&parents);
999 if (commit == head_commit)
1000 *head_subsumed = 0;
1001 else
1002 remotes = &commit_list_insert(commit, remotes)->next;
1003 }
1004 return remoteheads;
1005 }
1006
1007 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1008 {
1009 struct fmt_merge_msg_opts opts;
1010
1011 memset(&opts, 0, sizeof(opts));
1012 opts.add_title = !have_message;
1013 opts.shortlog_len = shortlog_len;
1014 opts.credit_people = (0 < option_edit);
1015
1016 fmt_merge_msg(merge_names, merge_msg, &opts);
1017 if (merge_msg->len)
1018 strbuf_setlen(merge_msg, merge_msg->len - 1);
1019 }
1020
1021 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1022 {
1023 const char *filename;
1024 int fd, pos, npos;
1025 struct strbuf fetch_head_file = STRBUF_INIT;
1026
1027 if (!merge_names)
1028 merge_names = &fetch_head_file;
1029
1030 filename = git_path_fetch_head();
1031 fd = open(filename, O_RDONLY);
1032 if (fd < 0)
1033 die_errno(_("could not open '%s' for reading"), filename);
1034
1035 if (strbuf_read(merge_names, fd, 0) < 0)
1036 die_errno(_("could not read '%s'"), filename);
1037 if (close(fd) < 0)
1038 die_errno(_("could not close '%s'"), filename);
1039
1040 for (pos = 0; pos < merge_names->len; pos = npos) {
1041 unsigned char sha1[20];
1042 char *ptr;
1043 struct commit *commit;
1044
1045 ptr = strchr(merge_names->buf + pos, '\n');
1046 if (ptr)
1047 npos = ptr - merge_names->buf + 1;
1048 else
1049 npos = merge_names->len;
1050
1051 if (npos - pos < 40 + 2 ||
1052 get_sha1_hex(merge_names->buf + pos, sha1))
1053 commit = NULL; /* bad */
1054 else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
1055 continue; /* not-for-merge */
1056 else {
1057 char saved = merge_names->buf[pos + 40];
1058 merge_names->buf[pos + 40] = '\0';
1059 commit = get_merge_parent(merge_names->buf + pos);
1060 merge_names->buf[pos + 40] = saved;
1061 }
1062 if (!commit) {
1063 if (ptr)
1064 *ptr = '\0';
1065 die(_("not something we can merge in %s: %s"),
1066 filename, merge_names->buf + pos);
1067 }
1068 remotes = &commit_list_insert(commit, remotes)->next;
1069 }
1070
1071 if (merge_names == &fetch_head_file)
1072 strbuf_release(&fetch_head_file);
1073 }
1074
1075 static struct commit_list *collect_parents(struct commit *head_commit,
1076 int *head_subsumed,
1077 int argc, const char **argv,
1078 struct strbuf *merge_msg)
1079 {
1080 int i;
1081 struct commit_list *remoteheads = NULL;
1082 struct commit_list **remotes = &remoteheads;
1083 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1084
1085 if (merge_msg && (!have_message || shortlog_len))
1086 autogen = &merge_names;
1087
1088 if (head_commit)
1089 remotes = &commit_list_insert(head_commit, remotes)->next;
1090
1091 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1092 handle_fetch_head(remotes, autogen);
1093 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1094 } else {
1095 for (i = 0; i < argc; i++) {
1096 struct commit *commit = get_merge_parent(argv[i]);
1097 if (!commit)
1098 help_unknown_ref(argv[i], "merge",
1099 _("not something we can merge"));
1100 remotes = &commit_list_insert(commit, remotes)->next;
1101 }
1102 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1103 if (autogen) {
1104 struct commit_list *p;
1105 for (p = remoteheads; p; p = p->next)
1106 merge_name(merge_remote_util(p->item)->name, autogen);
1107 }
1108 }
1109
1110 if (autogen) {
1111 prepare_merge_message(autogen, merge_msg);
1112 strbuf_release(autogen);
1113 }
1114
1115 return remoteheads;
1116 }
1117
1118 int cmd_merge(int argc, const char **argv, const char *prefix)
1119 {
1120 unsigned char result_tree[20];
1121 unsigned char stash[20];
1122 unsigned char head_sha1[20];
1123 struct commit *head_commit;
1124 struct strbuf buf = STRBUF_INIT;
1125 const char *head_arg;
1126 int i, ret = 0, head_subsumed;
1127 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1128 struct commit_list *common = NULL;
1129 const char *best_strategy = NULL, *wt_strategy = NULL;
1130 struct commit_list *remoteheads, *p;
1131 void *branch_to_free;
1132 int orig_argc = argc;
1133
1134 if (argc == 2 && !strcmp(argv[1], "-h"))
1135 usage_with_options(builtin_merge_usage, builtin_merge_options);
1136
1137 /*
1138 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1139 * current branch.
1140 */
1141 branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, NULL);
1142 if (branch && starts_with(branch, "refs/heads/"))
1143 branch += 11;
1144 if (!branch || is_null_sha1(head_sha1))
1145 head_commit = NULL;
1146 else
1147 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1148
1149 init_diff_ui_defaults();
1150 git_config(git_merge_config, NULL);
1151
1152 if (branch_mergeoptions)
1153 parse_branch_merge_options(branch_mergeoptions);
1154 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1155 builtin_merge_usage, 0);
1156 if (shortlog_len < 0)
1157 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1158
1159 if (verbosity < 0 && show_progress == -1)
1160 show_progress = 0;
1161
1162 if (abort_current_merge) {
1163 int nargc = 2;
1164 const char *nargv[] = {"reset", "--merge", NULL};
1165
1166 if (orig_argc != 2)
1167 usage_msg_opt(_("--abort expects no arguments"),
1168 builtin_merge_usage, builtin_merge_options);
1169
1170 if (!file_exists(git_path_merge_head()))
1171 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1172
1173 /* Invoke 'git reset --merge' */
1174 ret = cmd_reset(nargc, nargv, prefix);
1175 goto done;
1176 }
1177
1178 if (continue_current_merge) {
1179 int nargc = 1;
1180 const char *nargv[] = {"commit", NULL};
1181
1182 if (orig_argc != 2)
1183 usage_msg_opt(_("--continue expects no arguments"),
1184 builtin_merge_usage, builtin_merge_options);
1185
1186 if (!file_exists(git_path_merge_head()))
1187 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1188
1189 /* Invoke 'git commit' */
1190 ret = cmd_commit(nargc, nargv, prefix);
1191 goto done;
1192 }
1193
1194 if (read_cache_unmerged())
1195 die_resolve_conflict("merge");
1196
1197 if (file_exists(git_path_merge_head())) {
1198 /*
1199 * There is no unmerged entry, don't advise 'git
1200 * add/rm <file>', just 'git commit'.
1201 */
1202 if (advice_resolve_conflict)
1203 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1204 "Please, commit your changes before you merge."));
1205 else
1206 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1207 }
1208 if (file_exists(git_path_cherry_pick_head())) {
1209 if (advice_resolve_conflict)
1210 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1211 "Please, commit your changes before you merge."));
1212 else
1213 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1214 }
1215 resolve_undo_clear();
1216
1217 if (verbosity < 0)
1218 show_diffstat = 0;
1219
1220 if (squash) {
1221 if (fast_forward == FF_NO)
1222 die(_("You cannot combine --squash with --no-ff."));
1223 option_commit = 0;
1224 }
1225
1226 if (!argc) {
1227 if (default_to_upstream)
1228 argc = setup_with_upstream(&argv);
1229 else
1230 die(_("No commit specified and merge.defaultToUpstream not set."));
1231 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1232 argv[0] = "@{-1}";
1233 }
1234
1235 if (!argc)
1236 usage_with_options(builtin_merge_usage,
1237 builtin_merge_options);
1238
1239 if (!head_commit) {
1240 /*
1241 * If the merged head is a valid one there is no reason
1242 * to forbid "git merge" into a branch yet to be born.
1243 * We do the same for "git pull".
1244 */
1245 unsigned char *remote_head_sha1;
1246 if (squash)
1247 die(_("Squash commit into empty head not supported yet"));
1248 if (fast_forward == FF_NO)
1249 die(_("Non-fast-forward commit does not make sense into "
1250 "an empty head"));
1251 remoteheads = collect_parents(head_commit, &head_subsumed,
1252 argc, argv, NULL);
1253 if (!remoteheads)
1254 die(_("%s - not something we can merge"), argv[0]);
1255 if (remoteheads->next)
1256 die(_("Can merge only exactly one commit into empty head"));
1257 remote_head_sha1 = remoteheads->item->object.oid.hash;
1258 read_empty(remote_head_sha1, 0);
1259 update_ref("initial pull", "HEAD", remote_head_sha1,
1260 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1261 goto done;
1262 }
1263
1264 /*
1265 * This could be traditional "merge <msg> HEAD <commit>..." and
1266 * the way we can tell it is to see if the second token is HEAD,
1267 * but some people might have misused the interface and used a
1268 * commit-ish that is the same as HEAD there instead.
1269 * Traditional format never would have "-m" so it is an
1270 * additional safety measure to check for it.
1271 */
1272 if (!have_message &&
1273 is_old_style_invocation(argc, argv, head_commit->object.oid.hash)) {
1274 warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
1275 strbuf_addstr(&merge_msg, argv[0]);
1276 head_arg = argv[1];
1277 argv += 2;
1278 argc -= 2;
1279 remoteheads = collect_parents(head_commit, &head_subsumed,
1280 argc, argv, NULL);
1281 } else {
1282 /* We are invoked directly as the first-class UI. */
1283 head_arg = "HEAD";
1284
1285 /*
1286 * All the rest are the commits being merged; prepare
1287 * the standard merge summary message to be appended
1288 * to the given message.
1289 */
1290 remoteheads = collect_parents(head_commit, &head_subsumed,
1291 argc, argv, &merge_msg);
1292 }
1293
1294 if (!head_commit || !argc)
1295 usage_with_options(builtin_merge_usage,
1296 builtin_merge_options);
1297
1298 if (verify_signatures) {
1299 for (p = remoteheads; p; p = p->next) {
1300 struct commit *commit = p->item;
1301 char hex[GIT_SHA1_HEXSZ + 1];
1302 struct signature_check signature_check;
1303 memset(&signature_check, 0, sizeof(signature_check));
1304
1305 check_commit_signature(commit, &signature_check);
1306
1307 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1308 switch (signature_check.result) {
1309 case 'G':
1310 break;
1311 case 'U':
1312 die(_("Commit %s has an untrusted GPG signature, "
1313 "allegedly by %s."), hex, signature_check.signer);
1314 case 'B':
1315 die(_("Commit %s has a bad GPG signature "
1316 "allegedly by %s."), hex, signature_check.signer);
1317 default: /* 'N' */
1318 die(_("Commit %s does not have a GPG signature."), hex);
1319 }
1320 if (verbosity >= 0 && signature_check.result == 'G')
1321 printf(_("Commit %s has a good GPG signature by %s\n"),
1322 hex, signature_check.signer);
1323
1324 signature_check_clear(&signature_check);
1325 }
1326 }
1327
1328 strbuf_addstr(&buf, "merge");
1329 for (p = remoteheads; p; p = p->next)
1330 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1331 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1332 strbuf_reset(&buf);
1333
1334 for (p = remoteheads; p; p = p->next) {
1335 struct commit *commit = p->item;
1336 strbuf_addf(&buf, "GITHEAD_%s",
1337 oid_to_hex(&commit->object.oid));
1338 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1339 strbuf_reset(&buf);
1340 if (fast_forward != FF_ONLY &&
1341 merge_remote_util(commit) &&
1342 merge_remote_util(commit)->obj &&
1343 merge_remote_util(commit)->obj->type == OBJ_TAG)
1344 fast_forward = FF_NO;
1345 }
1346
1347 if (option_edit < 0)
1348 option_edit = default_edit_option();
1349
1350 if (!use_strategies) {
1351 if (!remoteheads)
1352 ; /* already up-to-date */
1353 else if (!remoteheads->next)
1354 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1355 else
1356 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1357 }
1358
1359 for (i = 0; i < use_strategies_nr; i++) {
1360 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1361 fast_forward = FF_NO;
1362 if (use_strategies[i]->attr & NO_TRIVIAL)
1363 allow_trivial = 0;
1364 }
1365
1366 if (!remoteheads)
1367 ; /* already up-to-date */
1368 else if (!remoteheads->next)
1369 common = get_merge_bases(head_commit, remoteheads->item);
1370 else {
1371 struct commit_list *list = remoteheads;
1372 commit_list_insert(head_commit, &list);
1373 common = get_octopus_merge_bases(list);
1374 free(list);
1375 }
1376
1377 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
1378 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1379
1380 if (remoteheads && !common) {
1381 /* No common ancestors found. */
1382 if (!allow_unrelated_histories)
1383 die(_("refusing to merge unrelated histories"));
1384 /* otherwise, we need a real merge. */
1385 } else if (!remoteheads ||
1386 (!remoteheads->next && !common->next &&
1387 common->item == remoteheads->item)) {
1388 /*
1389 * If head can reach all the merge then we are up to date.
1390 * but first the most common case of merging one remote.
1391 */
1392 finish_up_to_date(_("Already up-to-date."));
1393 goto done;
1394 } else if (fast_forward != FF_NO && !remoteheads->next &&
1395 !common->next &&
1396 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1397 /* Again the most common case of merging one remote. */
1398 struct strbuf msg = STRBUF_INIT;
1399 struct commit *commit;
1400
1401 if (verbosity >= 0) {
1402 printf(_("Updating %s..%s\n"),
1403 find_unique_abbrev(head_commit->object.oid.hash,
1404 DEFAULT_ABBREV),
1405 find_unique_abbrev(remoteheads->item->object.oid.hash,
1406 DEFAULT_ABBREV));
1407 }
1408 strbuf_addstr(&msg, "Fast-forward");
1409 if (have_message)
1410 strbuf_addstr(&msg,
1411 " (no commit created; -m option ignored)");
1412 commit = remoteheads->item;
1413 if (!commit) {
1414 ret = 1;
1415 goto done;
1416 }
1417
1418 if (checkout_fast_forward(head_commit->object.oid.hash,
1419 commit->object.oid.hash,
1420 overwrite_ignore)) {
1421 ret = 1;
1422 goto done;
1423 }
1424
1425 finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
1426 drop_save();
1427 goto done;
1428 } else if (!remoteheads->next && common->next)
1429 ;
1430 /*
1431 * We are not doing octopus and not fast-forward. Need
1432 * a real merge.
1433 */
1434 else if (!remoteheads->next && !common->next && option_commit) {
1435 /*
1436 * We are not doing octopus, not fast-forward, and have
1437 * only one common.
1438 */
1439 refresh_cache(REFRESH_QUIET);
1440 if (allow_trivial && fast_forward != FF_ONLY) {
1441 /* See if it is really trivial. */
1442 git_committer_info(IDENT_STRICT);
1443 printf(_("Trying really trivial in-index merge...\n"));
1444 if (!read_tree_trivial(common->item->object.oid.hash,
1445 head_commit->object.oid.hash,
1446 remoteheads->item->object.oid.hash)) {
1447 ret = merge_trivial(head_commit, remoteheads);
1448 goto done;
1449 }
1450 printf(_("Nope.\n"));
1451 }
1452 } else {
1453 /*
1454 * An octopus. If we can reach all the remote we are up
1455 * to date.
1456 */
1457 int up_to_date = 1;
1458 struct commit_list *j;
1459
1460 for (j = remoteheads; j; j = j->next) {
1461 struct commit_list *common_one;
1462
1463 /*
1464 * Here we *have* to calculate the individual
1465 * merge_bases again, otherwise "git merge HEAD^
1466 * HEAD^^" would be missed.
1467 */
1468 common_one = get_merge_bases(head_commit, j->item);
1469 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1470 up_to_date = 0;
1471 break;
1472 }
1473 }
1474 if (up_to_date) {
1475 finish_up_to_date(_("Already up-to-date. Yeeah!"));
1476 goto done;
1477 }
1478 }
1479
1480 if (fast_forward == FF_ONLY)
1481 die(_("Not possible to fast-forward, aborting."));
1482
1483 /* We are going to make a new commit. */
1484 git_committer_info(IDENT_STRICT);
1485
1486 /*
1487 * At this point, we need a real merge. No matter what strategy
1488 * we use, it would operate on the index, possibly affecting the
1489 * working tree, and when resolved cleanly, have the desired
1490 * tree in the index -- this means that the index must be in
1491 * sync with the head commit. The strategies are responsible
1492 * to ensure this.
1493 */
1494 if (use_strategies_nr == 1 ||
1495 /*
1496 * Stash away the local changes so that we can try more than one.
1497 */
1498 save_state(stash))
1499 hashclr(stash);
1500
1501 for (i = 0; i < use_strategies_nr; i++) {
1502 int ret;
1503 if (i) {
1504 printf(_("Rewinding the tree to pristine...\n"));
1505 restore_state(head_commit->object.oid.hash, stash);
1506 }
1507 if (use_strategies_nr != 1)
1508 printf(_("Trying merge strategy %s...\n"),
1509 use_strategies[i]->name);
1510 /*
1511 * Remember which strategy left the state in the working
1512 * tree.
1513 */
1514 wt_strategy = use_strategies[i]->name;
1515
1516 ret = try_merge_strategy(use_strategies[i]->name,
1517 common, remoteheads,
1518 head_commit, head_arg);
1519 if (!option_commit && !ret) {
1520 merge_was_ok = 1;
1521 /*
1522 * This is necessary here just to avoid writing
1523 * the tree, but later we will *not* exit with
1524 * status code 1 because merge_was_ok is set.
1525 */
1526 ret = 1;
1527 }
1528
1529 if (ret) {
1530 /*
1531 * The backend exits with 1 when conflicts are
1532 * left to be resolved, with 2 when it does not
1533 * handle the given merge at all.
1534 */
1535 if (ret == 1) {
1536 int cnt = evaluate_result();
1537
1538 if (best_cnt <= 0 || cnt <= best_cnt) {
1539 best_strategy = use_strategies[i]->name;
1540 best_cnt = cnt;
1541 }
1542 }
1543 if (merge_was_ok)
1544 break;
1545 else
1546 continue;
1547 }
1548
1549 /* Automerge succeeded. */
1550 write_tree_trivial(result_tree);
1551 automerge_was_ok = 1;
1552 break;
1553 }
1554
1555 /*
1556 * If we have a resulting tree, that means the strategy module
1557 * auto resolved the merge cleanly.
1558 */
1559 if (automerge_was_ok) {
1560 ret = finish_automerge(head_commit, head_subsumed,
1561 common, remoteheads,
1562 result_tree, wt_strategy);
1563 goto done;
1564 }
1565
1566 /*
1567 * Pick the result from the best strategy and have the user fix
1568 * it up.
1569 */
1570 if (!best_strategy) {
1571 restore_state(head_commit->object.oid.hash, stash);
1572 if (use_strategies_nr > 1)
1573 fprintf(stderr,
1574 _("No merge strategy handled the merge.\n"));
1575 else
1576 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1577 use_strategies[0]->name);
1578 ret = 2;
1579 goto done;
1580 } else if (best_strategy == wt_strategy)
1581 ; /* We already have its result in the working tree. */
1582 else {
1583 printf(_("Rewinding the tree to pristine...\n"));
1584 restore_state(head_commit->object.oid.hash, stash);
1585 printf(_("Using the %s to prepare resolving by hand.\n"),
1586 best_strategy);
1587 try_merge_strategy(best_strategy, common, remoteheads,
1588 head_commit, head_arg);
1589 }
1590
1591 if (squash)
1592 finish(head_commit, remoteheads, NULL, NULL);
1593 else
1594 write_merge_state(remoteheads);
1595
1596 if (merge_was_ok)
1597 fprintf(stderr, _("Automatic merge went well; "
1598 "stopped before committing as requested\n"));
1599 else
1600 ret = suggest_conflicts();
1601
1602 done:
1603 free(branch_to_free);
1604 return ret;
1605 }
git for Debian