cherry-pick/revert: add scissors line on merge conflict
[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 #define USE_THE_INDEX_COMPATIBILITY_MACROS
10 #include "cache.h"
11 #include "config.h"
12 #include "parse-options.h"
13 #include "builtin.h"
14 #include "lockfile.h"
15 #include "run-command.h"
16 #include "diff.h"
17 #include "refs.h"
18 #include "refspec.h"
19 #include "commit.h"
20 #include "diffcore.h"
21 #include "revision.h"
22 #include "unpack-trees.h"
23 #include "cache-tree.h"
24 #include "dir.h"
25 #include "utf8.h"
26 #include "log-tree.h"
27 #include "color.h"
28 #include "rerere.h"
29 #include "help.h"
30 #include "merge-recursive.h"
31 #include "resolve-undo.h"
32 #include "remote.h"
33 #include "fmt-merge-msg.h"
34 #include "gpg-interface.h"
35 #include "sequencer.h"
36 #include "string-list.h"
37 #include "packfile.h"
38 #include "tag.h"
39 #include "alias.h"
40 #include "commit-reach.h"
41 #include "wt-status.h"
42
43 #define DEFAULT_TWOHEAD (1<<0)
44 #define DEFAULT_OCTOPUS (1<<1)
45 #define NO_FAST_FORWARD (1<<2)
46 #define NO_TRIVIAL (1<<3)
47
48 struct strategy {
49 const char *name;
50 unsigned attr;
51 };
52
53 static const char * const builtin_merge_usage[] = {
54 N_("git merge [<options>] [<commit>...]"),
55 N_("git merge --abort"),
56 N_("git merge --continue"),
57 NULL
58 };
59
60 static int show_diffstat = 1, shortlog_len = -1, squash;
61 static int option_commit = 1;
62 static int option_edit = -1;
63 static int allow_trivial = 1, have_message, verify_signatures;
64 static int overwrite_ignore = 1;
65 static struct strbuf merge_msg = STRBUF_INIT;
66 static struct strategy **use_strategies;
67 static size_t use_strategies_nr, use_strategies_alloc;
68 static const char **xopts;
69 static size_t xopts_nr, xopts_alloc;
70 static const char *branch;
71 static char *branch_mergeoptions;
72 static int option_renormalize;
73 static int verbosity;
74 static int allow_rerere_auto;
75 static int abort_current_merge;
76 static int continue_current_merge;
77 static int allow_unrelated_histories;
78 static int show_progress = -1;
79 static int default_to_upstream = 1;
80 static int signoff;
81 static const char *sign_commit;
82 static int verify_msg = 1;
83
84 static struct strategy all_strategy[] = {
85 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
86 { "octopus", DEFAULT_OCTOPUS },
87 { "resolve", 0 },
88 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
89 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
90 };
91
92 static const char *pull_twohead, *pull_octopus;
93
94 enum ff_type {
95 FF_NO,
96 FF_ALLOW,
97 FF_ONLY
98 };
99
100 static enum ff_type fast_forward = FF_ALLOW;
101
102 static const char *cleanup_arg;
103 static enum commit_msg_cleanup_mode cleanup_mode;
104
105 static int option_parse_message(const struct option *opt,
106 const char *arg, int unset)
107 {
108 struct strbuf *buf = opt->value;
109
110 if (unset)
111 strbuf_setlen(buf, 0);
112 else if (arg) {
113 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
114 have_message = 1;
115 } else
116 return error(_("switch `m' requires a value"));
117 return 0;
118 }
119
120 static enum parse_opt_result option_read_message(struct parse_opt_ctx_t *ctx,
121 const struct option *opt,
122 const char *arg_not_used,
123 int unset)
124 {
125 struct strbuf *buf = opt->value;
126 const char *arg;
127
128 BUG_ON_OPT_ARG(arg_not_used);
129 if (unset)
130 BUG("-F cannot be negated");
131
132 if (ctx->opt) {
133 arg = ctx->opt;
134 ctx->opt = NULL;
135 } else if (ctx->argc > 1) {
136 ctx->argc--;
137 arg = *++ctx->argv;
138 } else
139 return error(_("option `%s' requires a value"), opt->long_name);
140
141 if (buf->len)
142 strbuf_addch(buf, '\n');
143 if (ctx->prefix && !is_absolute_path(arg))
144 arg = prefix_filename(ctx->prefix, arg);
145 if (strbuf_read_file(buf, arg, 0) < 0)
146 return error(_("could not read file '%s'"), arg);
147 have_message = 1;
148
149 return 0;
150 }
151
152 static struct strategy *get_strategy(const char *name)
153 {
154 int i;
155 struct strategy *ret;
156 static struct cmdnames main_cmds, other_cmds;
157 static int loaded;
158
159 if (!name)
160 return NULL;
161
162 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
163 if (!strcmp(name, all_strategy[i].name))
164 return &all_strategy[i];
165
166 if (!loaded) {
167 struct cmdnames not_strategies;
168 loaded = 1;
169
170 memset(&not_strategies, 0, sizeof(struct cmdnames));
171 load_command_list("git-merge-", &main_cmds, &other_cmds);
172 for (i = 0; i < main_cmds.cnt; i++) {
173 int j, found = 0;
174 struct cmdname *ent = main_cmds.names[i];
175 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
176 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
177 && !all_strategy[j].name[ent->len])
178 found = 1;
179 if (!found)
180 add_cmdname(&not_strategies, ent->name, ent->len);
181 }
182 exclude_cmds(&main_cmds, &not_strategies);
183 }
184 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
185 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
186 fprintf(stderr, _("Available strategies are:"));
187 for (i = 0; i < main_cmds.cnt; i++)
188 fprintf(stderr, " %s", main_cmds.names[i]->name);
189 fprintf(stderr, ".\n");
190 if (other_cmds.cnt) {
191 fprintf(stderr, _("Available custom strategies are:"));
192 for (i = 0; i < other_cmds.cnt; i++)
193 fprintf(stderr, " %s", other_cmds.names[i]->name);
194 fprintf(stderr, ".\n");
195 }
196 exit(1);
197 }
198
199 ret = xcalloc(1, sizeof(struct strategy));
200 ret->name = xstrdup(name);
201 ret->attr = NO_TRIVIAL;
202 return ret;
203 }
204
205 static void append_strategy(struct strategy *s)
206 {
207 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
208 use_strategies[use_strategies_nr++] = s;
209 }
210
211 static int option_parse_strategy(const struct option *opt,
212 const char *name, int unset)
213 {
214 if (unset)
215 return 0;
216
217 append_strategy(get_strategy(name));
218 return 0;
219 }
220
221 static int option_parse_x(const struct option *opt,
222 const char *arg, int unset)
223 {
224 if (unset)
225 return 0;
226
227 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
228 xopts[xopts_nr++] = xstrdup(arg);
229 return 0;
230 }
231
232 static int option_parse_n(const struct option *opt,
233 const char *arg, int unset)
234 {
235 BUG_ON_OPT_ARG(arg);
236 show_diffstat = unset;
237 return 0;
238 }
239
240 static struct option builtin_merge_options[] = {
241 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
242 N_("do not show a diffstat at the end of the merge"),
243 PARSE_OPT_NOARG, option_parse_n },
244 OPT_BOOL(0, "stat", &show_diffstat,
245 N_("show a diffstat at the end of the merge")),
246 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
247 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
248 N_("add (at most <n>) entries from shortlog to merge commit message"),
249 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
250 OPT_BOOL(0, "squash", &squash,
251 N_("create a single commit instead of doing a merge")),
252 OPT_BOOL(0, "commit", &option_commit,
253 N_("perform a commit if the merge succeeds (default)")),
254 OPT_BOOL('e', "edit", &option_edit,
255 N_("edit message before committing")),
256 OPT_CLEANUP(&cleanup_arg),
257 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
258 OPT_SET_INT_F(0, "ff-only", &fast_forward,
259 N_("abort if fast-forward is not possible"),
260 FF_ONLY, PARSE_OPT_NONEG),
261 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
262 OPT_BOOL(0, "verify-signatures", &verify_signatures,
263 N_("verify that the named commit has a valid GPG signature")),
264 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
265 N_("merge strategy to use"), option_parse_strategy),
266 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
267 N_("option for selected merge strategy"), option_parse_x),
268 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
269 N_("merge commit message (for a non-fast-forward merge)"),
270 option_parse_message),
271 { OPTION_LOWLEVEL_CALLBACK, 'F', "file", &merge_msg, N_("path"),
272 N_("read message from file"), PARSE_OPT_NONEG,
273 NULL, 0, option_read_message },
274 OPT__VERBOSITY(&verbosity),
275 OPT_BOOL(0, "abort", &abort_current_merge,
276 N_("abort the current in-progress merge")),
277 OPT_BOOL(0, "continue", &continue_current_merge,
278 N_("continue the current in-progress merge")),
279 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
280 N_("allow merging unrelated histories")),
281 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
282 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
283 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
284 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
285 OPT_BOOL(0, "signoff", &signoff, N_("add Signed-off-by:")),
286 OPT_BOOL(0, "verify", &verify_msg, N_("verify commit-msg hook")),
287 OPT_END()
288 };
289
290 /* Cleans up metadata that is uninteresting after a succeeded merge. */
291 static void drop_save(void)
292 {
293 unlink(git_path_merge_head(the_repository));
294 unlink(git_path_merge_msg(the_repository));
295 unlink(git_path_merge_mode(the_repository));
296 }
297
298 static int save_state(struct object_id *stash)
299 {
300 int len;
301 struct child_process cp = CHILD_PROCESS_INIT;
302 struct strbuf buffer = STRBUF_INIT;
303 const char *argv[] = {"stash", "create", NULL};
304 int rc = -1;
305
306 cp.argv = argv;
307 cp.out = -1;
308 cp.git_cmd = 1;
309
310 if (start_command(&cp))
311 die(_("could not run stash."));
312 len = strbuf_read(&buffer, cp.out, 1024);
313 close(cp.out);
314
315 if (finish_command(&cp) || len < 0)
316 die(_("stash failed"));
317 else if (!len) /* no changes */
318 goto out;
319 strbuf_setlen(&buffer, buffer.len-1);
320 if (get_oid(buffer.buf, stash))
321 die(_("not a valid object: %s"), buffer.buf);
322 rc = 0;
323 out:
324 strbuf_release(&buffer);
325 return rc;
326 }
327
328 static void read_empty(const struct object_id *oid, int verbose)
329 {
330 int i = 0;
331 const char *args[7];
332
333 args[i++] = "read-tree";
334 if (verbose)
335 args[i++] = "-v";
336 args[i++] = "-m";
337 args[i++] = "-u";
338 args[i++] = empty_tree_oid_hex();
339 args[i++] = oid_to_hex(oid);
340 args[i] = NULL;
341
342 if (run_command_v_opt(args, RUN_GIT_CMD))
343 die(_("read-tree failed"));
344 }
345
346 static void reset_hard(const struct object_id *oid, int verbose)
347 {
348 int i = 0;
349 const char *args[6];
350
351 args[i++] = "read-tree";
352 if (verbose)
353 args[i++] = "-v";
354 args[i++] = "--reset";
355 args[i++] = "-u";
356 args[i++] = oid_to_hex(oid);
357 args[i] = NULL;
358
359 if (run_command_v_opt(args, RUN_GIT_CMD))
360 die(_("read-tree failed"));
361 }
362
363 static void restore_state(const struct object_id *head,
364 const struct object_id *stash)
365 {
366 struct strbuf sb = STRBUF_INIT;
367 const char *args[] = { "stash", "apply", NULL, NULL };
368
369 if (is_null_oid(stash))
370 return;
371
372 reset_hard(head, 1);
373
374 args[2] = oid_to_hex(stash);
375
376 /*
377 * It is OK to ignore error here, for example when there was
378 * nothing to restore.
379 */
380 run_command_v_opt(args, RUN_GIT_CMD);
381
382 strbuf_release(&sb);
383 refresh_cache(REFRESH_QUIET);
384 }
385
386 /* This is called when no merge was necessary. */
387 static void finish_up_to_date(const char *msg)
388 {
389 if (verbosity >= 0)
390 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
391 drop_save();
392 }
393
394 static void squash_message(struct commit *commit, struct commit_list *remoteheads)
395 {
396 struct rev_info rev;
397 struct strbuf out = STRBUF_INIT;
398 struct commit_list *j;
399 struct pretty_print_context ctx = {0};
400
401 printf(_("Squash commit -- not updating HEAD\n"));
402
403 repo_init_revisions(the_repository, &rev, NULL);
404 rev.ignore_merges = 1;
405 rev.commit_format = CMIT_FMT_MEDIUM;
406
407 commit->object.flags |= UNINTERESTING;
408 add_pending_object(&rev, &commit->object, NULL);
409
410 for (j = remoteheads; j; j = j->next)
411 add_pending_object(&rev, &j->item->object, NULL);
412
413 setup_revisions(0, NULL, &rev, NULL);
414 if (prepare_revision_walk(&rev))
415 die(_("revision walk setup failed"));
416
417 ctx.abbrev = rev.abbrev;
418 ctx.date_mode = rev.date_mode;
419 ctx.fmt = rev.commit_format;
420
421 strbuf_addstr(&out, "Squashed commit of the following:\n");
422 while ((commit = get_revision(&rev)) != NULL) {
423 strbuf_addch(&out, '\n');
424 strbuf_addf(&out, "commit %s\n",
425 oid_to_hex(&commit->object.oid));
426 pretty_print_commit(&ctx, commit, &out);
427 }
428 write_file_buf(git_path_squash_msg(the_repository), out.buf, out.len);
429 strbuf_release(&out);
430 }
431
432 static void finish(struct commit *head_commit,
433 struct commit_list *remoteheads,
434 const struct object_id *new_head, const char *msg)
435 {
436 struct strbuf reflog_message = STRBUF_INIT;
437 const struct object_id *head = &head_commit->object.oid;
438
439 if (!msg)
440 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
441 else {
442 if (verbosity >= 0)
443 printf("%s\n", msg);
444 strbuf_addf(&reflog_message, "%s: %s",
445 getenv("GIT_REFLOG_ACTION"), msg);
446 }
447 if (squash) {
448 squash_message(head_commit, remoteheads);
449 } else {
450 if (verbosity >= 0 && !merge_msg.len)
451 printf(_("No merge message -- not updating HEAD\n"));
452 else {
453 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
454 update_ref(reflog_message.buf, "HEAD", new_head, head,
455 0, UPDATE_REFS_DIE_ON_ERR);
456 /*
457 * We ignore errors in 'gc --auto', since the
458 * user should see them.
459 */
460 close_all_packs(the_repository->objects);
461 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
462 }
463 }
464 if (new_head && show_diffstat) {
465 struct diff_options opts;
466 repo_diff_setup(the_repository, &opts);
467 opts.stat_width = -1; /* use full terminal width */
468 opts.stat_graph_width = -1; /* respect statGraphWidth config */
469 opts.output_format |=
470 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
471 opts.detect_rename = DIFF_DETECT_RENAME;
472 diff_setup_done(&opts);
473 diff_tree_oid(head, new_head, "", &opts);
474 diffcore_std(&opts);
475 diff_flush(&opts);
476 }
477
478 /* Run a post-merge hook */
479 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
480
481 strbuf_release(&reflog_message);
482 }
483
484 /* Get the name for the merge commit's message. */
485 static void merge_name(const char *remote, struct strbuf *msg)
486 {
487 struct commit *remote_head;
488 struct object_id branch_head;
489 struct strbuf buf = STRBUF_INIT;
490 struct strbuf bname = STRBUF_INIT;
491 struct merge_remote_desc *desc;
492 const char *ptr;
493 char *found_ref;
494 int len, early;
495
496 strbuf_branchname(&bname, remote, 0);
497 remote = bname.buf;
498
499 oidclr(&branch_head);
500 remote_head = get_merge_parent(remote);
501 if (!remote_head)
502 die(_("'%s' does not point to a commit"), remote);
503
504 if (dwim_ref(remote, strlen(remote), &branch_head, &found_ref) > 0) {
505 if (starts_with(found_ref, "refs/heads/")) {
506 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
507 oid_to_hex(&branch_head), remote);
508 goto cleanup;
509 }
510 if (starts_with(found_ref, "refs/tags/")) {
511 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
512 oid_to_hex(&branch_head), remote);
513 goto cleanup;
514 }
515 if (starts_with(found_ref, "refs/remotes/")) {
516 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
517 oid_to_hex(&branch_head), remote);
518 goto cleanup;
519 }
520 }
521
522 /* See if remote matches <name>^^^.. or <name>~<number> */
523 for (len = 0, ptr = remote + strlen(remote);
524 remote < ptr && ptr[-1] == '^';
525 ptr--)
526 len++;
527 if (len)
528 early = 1;
529 else {
530 early = 0;
531 ptr = strrchr(remote, '~');
532 if (ptr) {
533 int seen_nonzero = 0;
534
535 len++; /* count ~ */
536 while (*++ptr && isdigit(*ptr)) {
537 seen_nonzero |= (*ptr != '0');
538 len++;
539 }
540 if (*ptr)
541 len = 0; /* not ...~<number> */
542 else if (seen_nonzero)
543 early = 1;
544 else if (len == 1)
545 early = 1; /* "name~" is "name~1"! */
546 }
547 }
548 if (len) {
549 struct strbuf truname = STRBUF_INIT;
550 strbuf_addf(&truname, "refs/heads/%s", remote);
551 strbuf_setlen(&truname, truname.len - len);
552 if (ref_exists(truname.buf)) {
553 strbuf_addf(msg,
554 "%s\t\tbranch '%s'%s of .\n",
555 oid_to_hex(&remote_head->object.oid),
556 truname.buf + 11,
557 (early ? " (early part)" : ""));
558 strbuf_release(&truname);
559 goto cleanup;
560 }
561 strbuf_release(&truname);
562 }
563
564 desc = merge_remote_util(remote_head);
565 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
566 strbuf_addf(msg, "%s\t\t%s '%s'\n",
567 oid_to_hex(&desc->obj->oid),
568 type_name(desc->obj->type),
569 remote);
570 goto cleanup;
571 }
572
573 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
574 oid_to_hex(&remote_head->object.oid), remote);
575 cleanup:
576 strbuf_release(&buf);
577 strbuf_release(&bname);
578 }
579
580 static void parse_branch_merge_options(char *bmo)
581 {
582 const char **argv;
583 int argc;
584
585 if (!bmo)
586 return;
587 argc = split_cmdline(bmo, &argv);
588 if (argc < 0)
589 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
590 _(split_cmdline_strerror(argc)));
591 REALLOC_ARRAY(argv, argc + 2);
592 MOVE_ARRAY(argv + 1, argv, argc + 1);
593 argc++;
594 argv[0] = "branch.*.mergeoptions";
595 parse_options(argc, argv, NULL, builtin_merge_options,
596 builtin_merge_usage, 0);
597 free(argv);
598 }
599
600 static int git_merge_config(const char *k, const char *v, void *cb)
601 {
602 int status;
603
604 if (branch && starts_with(k, "branch.") &&
605 starts_with(k + 7, branch) &&
606 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
607 free(branch_mergeoptions);
608 branch_mergeoptions = xstrdup(v);
609 return 0;
610 }
611
612 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
613 show_diffstat = git_config_bool(k, v);
614 else if (!strcmp(k, "merge.verifysignatures"))
615 verify_signatures = git_config_bool(k, v);
616 else if (!strcmp(k, "pull.twohead"))
617 return git_config_string(&pull_twohead, k, v);
618 else if (!strcmp(k, "pull.octopus"))
619 return git_config_string(&pull_octopus, k, v);
620 else if (!strcmp(k, "commit.cleanup"))
621 return git_config_string(&cleanup_arg, k, v);
622 else if (!strcmp(k, "merge.renormalize"))
623 option_renormalize = git_config_bool(k, v);
624 else if (!strcmp(k, "merge.ff")) {
625 int boolval = git_parse_maybe_bool(v);
626 if (0 <= boolval) {
627 fast_forward = boolval ? FF_ALLOW : FF_NO;
628 } else if (v && !strcmp(v, "only")) {
629 fast_forward = FF_ONLY;
630 } /* do not barf on values from future versions of git */
631 return 0;
632 } else if (!strcmp(k, "merge.defaulttoupstream")) {
633 default_to_upstream = git_config_bool(k, v);
634 return 0;
635 } else if (!strcmp(k, "commit.gpgsign")) {
636 sign_commit = git_config_bool(k, v) ? "" : NULL;
637 return 0;
638 }
639
640 status = fmt_merge_msg_config(k, v, cb);
641 if (status)
642 return status;
643 status = git_gpg_config(k, v, NULL);
644 if (status)
645 return status;
646 return git_diff_ui_config(k, v, cb);
647 }
648
649 static int read_tree_trivial(struct object_id *common, struct object_id *head,
650 struct object_id *one)
651 {
652 int i, nr_trees = 0;
653 struct tree *trees[MAX_UNPACK_TREES];
654 struct tree_desc t[MAX_UNPACK_TREES];
655 struct unpack_trees_options opts;
656
657 memset(&opts, 0, sizeof(opts));
658 opts.head_idx = 2;
659 opts.src_index = &the_index;
660 opts.dst_index = &the_index;
661 opts.update = 1;
662 opts.verbose_update = 1;
663 opts.trivial_merges_only = 1;
664 opts.merge = 1;
665 trees[nr_trees] = parse_tree_indirect(common);
666 if (!trees[nr_trees++])
667 return -1;
668 trees[nr_trees] = parse_tree_indirect(head);
669 if (!trees[nr_trees++])
670 return -1;
671 trees[nr_trees] = parse_tree_indirect(one);
672 if (!trees[nr_trees++])
673 return -1;
674 opts.fn = threeway_merge;
675 cache_tree_free(&active_cache_tree);
676 for (i = 0; i < nr_trees; i++) {
677 parse_tree(trees[i]);
678 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
679 }
680 if (unpack_trees(nr_trees, t, &opts))
681 return -1;
682 return 0;
683 }
684
685 static void write_tree_trivial(struct object_id *oid)
686 {
687 if (write_cache_as_tree(oid, 0, NULL))
688 die(_("git write-tree failed to write a tree"));
689 }
690
691 static int try_merge_strategy(const char *strategy, struct commit_list *common,
692 struct commit_list *remoteheads,
693 struct commit *head)
694 {
695 struct lock_file lock = LOCK_INIT;
696 const char *head_arg = "HEAD";
697
698 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
699 refresh_cache(REFRESH_QUIET);
700 if (write_locked_index(&the_index, &lock,
701 COMMIT_LOCK | SKIP_IF_UNCHANGED))
702 return error(_("Unable to write index."));
703
704 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
705 int clean, x;
706 struct commit *result;
707 struct commit_list *reversed = NULL;
708 struct merge_options o;
709 struct commit_list *j;
710
711 if (remoteheads->next) {
712 error(_("Not handling anything other than two heads merge."));
713 return 2;
714 }
715
716 init_merge_options(&o, the_repository);
717 if (!strcmp(strategy, "subtree"))
718 o.subtree_shift = "";
719
720 o.renormalize = option_renormalize;
721 o.show_rename_progress =
722 show_progress == -1 ? isatty(2) : show_progress;
723
724 for (x = 0; x < xopts_nr; x++)
725 if (parse_merge_opt(&o, xopts[x]))
726 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
727
728 o.branch1 = head_arg;
729 o.branch2 = merge_remote_util(remoteheads->item)->name;
730
731 for (j = common; j; j = j->next)
732 commit_list_insert(j->item, &reversed);
733
734 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
735 clean = merge_recursive(&o, head,
736 remoteheads->item, reversed, &result);
737 if (clean < 0)
738 exit(128);
739 if (write_locked_index(&the_index, &lock,
740 COMMIT_LOCK | SKIP_IF_UNCHANGED))
741 die(_("unable to write %s"), get_index_file());
742 return clean ? 0 : 1;
743 } else {
744 return try_merge_command(the_repository,
745 strategy, xopts_nr, xopts,
746 common, head_arg, remoteheads);
747 }
748 }
749
750 static void count_diff_files(struct diff_queue_struct *q,
751 struct diff_options *opt, void *data)
752 {
753 int *count = data;
754
755 (*count) += q->nr;
756 }
757
758 static int count_unmerged_entries(void)
759 {
760 int i, ret = 0;
761
762 for (i = 0; i < active_nr; i++)
763 if (ce_stage(active_cache[i]))
764 ret++;
765
766 return ret;
767 }
768
769 static void add_strategies(const char *string, unsigned attr)
770 {
771 int i;
772
773 if (string) {
774 struct string_list list = STRING_LIST_INIT_DUP;
775 struct string_list_item *item;
776 string_list_split(&list, string, ' ', -1);
777 for_each_string_list_item(item, &list)
778 append_strategy(get_strategy(item->string));
779 string_list_clear(&list, 0);
780 return;
781 }
782 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
783 if (all_strategy[i].attr & attr)
784 append_strategy(&all_strategy[i]);
785
786 }
787
788 static void read_merge_msg(struct strbuf *msg)
789 {
790 const char *filename = git_path_merge_msg(the_repository);
791 strbuf_reset(msg);
792 if (strbuf_read_file(msg, filename, 0) < 0)
793 die_errno(_("Could not read from '%s'"), filename);
794 }
795
796 static void write_merge_state(struct commit_list *);
797 static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
798 {
799 if (err_msg)
800 error("%s", err_msg);
801 fprintf(stderr,
802 _("Not committing merge; use 'git commit' to complete the merge.\n"));
803 write_merge_state(remoteheads);
804 exit(1);
805 }
806
807 static const char merge_editor_comment[] =
808 N_("Please enter a commit message to explain why this merge is necessary,\n"
809 "especially if it merges an updated upstream into a topic branch.\n"
810 "\n");
811
812 static const char scissors_editor_comment[] =
813 N_("An empty message aborts the commit.\n");
814
815 static const char no_scissors_editor_comment[] =
816 N_("Lines starting with '%c' will be ignored, and an empty message aborts\n"
817 "the commit.\n");
818
819 static void write_merge_heads(struct commit_list *);
820 static void prepare_to_commit(struct commit_list *remoteheads)
821 {
822 struct strbuf msg = STRBUF_INIT;
823 strbuf_addbuf(&msg, &merge_msg);
824 if (squash)
825 BUG("the control must not reach here under --squash");
826 if (0 < option_edit) {
827 strbuf_addch(&msg, '\n');
828 if (cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS) {
829 wt_status_append_cut_line(&msg);
830 strbuf_commented_addf(&msg, "\n");
831 }
832 strbuf_commented_addf(&msg, _(merge_editor_comment));
833 strbuf_commented_addf(&msg, _(cleanup_mode == COMMIT_MSG_CLEANUP_SCISSORS ?
834 scissors_editor_comment :
835 no_scissors_editor_comment), comment_line_char);
836 }
837 if (signoff)
838 append_signoff(&msg, ignore_non_trailer(msg.buf, msg.len), 0);
839 write_merge_heads(remoteheads);
840 write_file_buf(git_path_merge_msg(the_repository), msg.buf, msg.len);
841 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
842 git_path_merge_msg(the_repository), "merge", NULL))
843 abort_commit(remoteheads, NULL);
844 if (0 < option_edit) {
845 if (launch_editor(git_path_merge_msg(the_repository), NULL, NULL))
846 abort_commit(remoteheads, NULL);
847 }
848
849 if (verify_msg && run_commit_hook(0 < option_edit, get_index_file(),
850 "commit-msg",
851 git_path_merge_msg(the_repository), NULL))
852 abort_commit(remoteheads, NULL);
853
854 read_merge_msg(&msg);
855 cleanup_message(&msg, cleanup_mode, 0);
856 if (!msg.len)
857 abort_commit(remoteheads, _("Empty commit message."));
858 strbuf_release(&merge_msg);
859 strbuf_addbuf(&merge_msg, &msg);
860 strbuf_release(&msg);
861 }
862
863 static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
864 {
865 struct object_id result_tree, result_commit;
866 struct commit_list *parents, **pptr = &parents;
867 struct lock_file lock = LOCK_INIT;
868
869 hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
870 refresh_cache(REFRESH_QUIET);
871 if (write_locked_index(&the_index, &lock,
872 COMMIT_LOCK | SKIP_IF_UNCHANGED))
873 return error(_("Unable to write index."));
874
875 write_tree_trivial(&result_tree);
876 printf(_("Wonderful.\n"));
877 pptr = commit_list_append(head, pptr);
878 pptr = commit_list_append(remoteheads->item, pptr);
879 prepare_to_commit(remoteheads);
880 if (commit_tree(merge_msg.buf, merge_msg.len, &result_tree, parents,
881 &result_commit, NULL, sign_commit))
882 die(_("failed to write commit object"));
883 finish(head, remoteheads, &result_commit, "In-index merge");
884 drop_save();
885 return 0;
886 }
887
888 static int finish_automerge(struct commit *head,
889 int head_subsumed,
890 struct commit_list *common,
891 struct commit_list *remoteheads,
892 struct object_id *result_tree,
893 const char *wt_strategy)
894 {
895 struct commit_list *parents = NULL;
896 struct strbuf buf = STRBUF_INIT;
897 struct object_id result_commit;
898
899 free_commit_list(common);
900 parents = remoteheads;
901 if (!head_subsumed || fast_forward == FF_NO)
902 commit_list_insert(head, &parents);
903 prepare_to_commit(remoteheads);
904 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
905 &result_commit, NULL, sign_commit))
906 die(_("failed to write commit object"));
907 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
908 finish(head, remoteheads, &result_commit, buf.buf);
909 strbuf_release(&buf);
910 drop_save();
911 return 0;
912 }
913
914 static int suggest_conflicts(void)
915 {
916 const char *filename;
917 FILE *fp;
918 struct strbuf msgbuf = STRBUF_INIT;
919
920 filename = git_path_merge_msg(the_repository);
921 fp = xfopen(filename, "a");
922
923 /*
924 * We can't use cleanup_mode because if we're not using the editor,
925 * get_cleanup_mode will return COMMIT_MSG_CLEANUP_SPACE instead, even
926 * though the message is meant to be processed later by git-commit.
927 * Thus, we will get the cleanup mode which is returned when we _are_
928 * using an editor.
929 */
930 append_conflicts_hint(&the_index, &msgbuf,
931 get_cleanup_mode(cleanup_arg, 1));
932 fputs(msgbuf.buf, fp);
933 strbuf_release(&msgbuf);
934 fclose(fp);
935 repo_rerere(the_repository, allow_rerere_auto);
936 printf(_("Automatic merge failed; "
937 "fix conflicts and then commit the result.\n"));
938 return 1;
939 }
940
941 static int evaluate_result(void)
942 {
943 int cnt = 0;
944 struct rev_info rev;
945
946 /* Check how many files differ. */
947 repo_init_revisions(the_repository, &rev, "");
948 setup_revisions(0, NULL, &rev, NULL);
949 rev.diffopt.output_format |=
950 DIFF_FORMAT_CALLBACK;
951 rev.diffopt.format_callback = count_diff_files;
952 rev.diffopt.format_callback_data = &cnt;
953 run_diff_files(&rev, 0);
954
955 /*
956 * Check how many unmerged entries are
957 * there.
958 */
959 cnt += count_unmerged_entries();
960
961 return cnt;
962 }
963
964 /*
965 * Pretend as if the user told us to merge with the remote-tracking
966 * branch we have for the upstream of the current branch
967 */
968 static int setup_with_upstream(const char ***argv)
969 {
970 struct branch *branch = branch_get(NULL);
971 int i;
972 const char **args;
973
974 if (!branch)
975 die(_("No current branch."));
976 if (!branch->remote_name)
977 die(_("No remote for the current branch."));
978 if (!branch->merge_nr)
979 die(_("No default upstream defined for the current branch."));
980
981 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
982 for (i = 0; i < branch->merge_nr; i++) {
983 if (!branch->merge[i]->dst)
984 die(_("No remote-tracking branch for %s from %s"),
985 branch->merge[i]->src, branch->remote_name);
986 args[i] = branch->merge[i]->dst;
987 }
988 args[i] = NULL;
989 *argv = args;
990 return i;
991 }
992
993 static void write_merge_heads(struct commit_list *remoteheads)
994 {
995 struct commit_list *j;
996 struct strbuf buf = STRBUF_INIT;
997
998 for (j = remoteheads; j; j = j->next) {
999 struct object_id *oid;
1000 struct commit *c = j->item;
1001 struct merge_remote_desc *desc;
1002
1003 desc = merge_remote_util(c);
1004 if (desc && desc->obj) {
1005 oid = &desc->obj->oid;
1006 } else {
1007 oid = &c->object.oid;
1008 }
1009 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
1010 }
1011 write_file_buf(git_path_merge_head(the_repository), buf.buf, buf.len);
1012
1013 strbuf_reset(&buf);
1014 if (fast_forward == FF_NO)
1015 strbuf_addstr(&buf, "no-ff");
1016 write_file_buf(git_path_merge_mode(the_repository), buf.buf, buf.len);
1017 strbuf_release(&buf);
1018 }
1019
1020 static void write_merge_state(struct commit_list *remoteheads)
1021 {
1022 write_merge_heads(remoteheads);
1023 strbuf_addch(&merge_msg, '\n');
1024 write_file_buf(git_path_merge_msg(the_repository), merge_msg.buf,
1025 merge_msg.len);
1026 }
1027
1028 static int default_edit_option(void)
1029 {
1030 static const char name[] = "GIT_MERGE_AUTOEDIT";
1031 const char *e = getenv(name);
1032 struct stat st_stdin, st_stdout;
1033
1034 if (have_message)
1035 /* an explicit -m msg without --[no-]edit */
1036 return 0;
1037
1038 if (e) {
1039 int v = git_parse_maybe_bool(e);
1040 if (v < 0)
1041 die(_("Bad value '%s' in environment '%s'"), e, name);
1042 return v;
1043 }
1044
1045 /* Use editor if stdin and stdout are the same and is a tty */
1046 return (!fstat(0, &st_stdin) &&
1047 !fstat(1, &st_stdout) &&
1048 isatty(0) && isatty(1) &&
1049 st_stdin.st_dev == st_stdout.st_dev &&
1050 st_stdin.st_ino == st_stdout.st_ino &&
1051 st_stdin.st_mode == st_stdout.st_mode);
1052 }
1053
1054 static struct commit_list *reduce_parents(struct commit *head_commit,
1055 int *head_subsumed,
1056 struct commit_list *remoteheads)
1057 {
1058 struct commit_list *parents, **remotes;
1059
1060 /*
1061 * Is the current HEAD reachable from another commit being
1062 * merged? If so we do not want to record it as a parent of
1063 * the resulting merge, unless --no-ff is given. We will flip
1064 * this variable to 0 when we find HEAD among the independent
1065 * tips being merged.
1066 */
1067 *head_subsumed = 1;
1068
1069 /* Find what parents to record by checking independent ones. */
1070 parents = reduce_heads(remoteheads);
1071 free_commit_list(remoteheads);
1072
1073 remoteheads = NULL;
1074 remotes = &remoteheads;
1075 while (parents) {
1076 struct commit *commit = pop_commit(&parents);
1077 if (commit == head_commit)
1078 *head_subsumed = 0;
1079 else
1080 remotes = &commit_list_insert(commit, remotes)->next;
1081 }
1082 return remoteheads;
1083 }
1084
1085 static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1086 {
1087 struct fmt_merge_msg_opts opts;
1088
1089 memset(&opts, 0, sizeof(opts));
1090 opts.add_title = !have_message;
1091 opts.shortlog_len = shortlog_len;
1092 opts.credit_people = (0 < option_edit);
1093
1094 fmt_merge_msg(merge_names, merge_msg, &opts);
1095 if (merge_msg->len)
1096 strbuf_setlen(merge_msg, merge_msg->len - 1);
1097 }
1098
1099 static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1100 {
1101 const char *filename;
1102 int fd, pos, npos;
1103 struct strbuf fetch_head_file = STRBUF_INIT;
1104 const unsigned hexsz = the_hash_algo->hexsz;
1105
1106 if (!merge_names)
1107 merge_names = &fetch_head_file;
1108
1109 filename = git_path_fetch_head(the_repository);
1110 fd = open(filename, O_RDONLY);
1111 if (fd < 0)
1112 die_errno(_("could not open '%s' for reading"), filename);
1113
1114 if (strbuf_read(merge_names, fd, 0) < 0)
1115 die_errno(_("could not read '%s'"), filename);
1116 if (close(fd) < 0)
1117 die_errno(_("could not close '%s'"), filename);
1118
1119 for (pos = 0; pos < merge_names->len; pos = npos) {
1120 struct object_id oid;
1121 char *ptr;
1122 struct commit *commit;
1123
1124 ptr = strchr(merge_names->buf + pos, '\n');
1125 if (ptr)
1126 npos = ptr - merge_names->buf + 1;
1127 else
1128 npos = merge_names->len;
1129
1130 if (npos - pos < hexsz + 2 ||
1131 get_oid_hex(merge_names->buf + pos, &oid))
1132 commit = NULL; /* bad */
1133 else if (memcmp(merge_names->buf + pos + hexsz, "\t\t", 2))
1134 continue; /* not-for-merge */
1135 else {
1136 char saved = merge_names->buf[pos + hexsz];
1137 merge_names->buf[pos + hexsz] = '\0';
1138 commit = get_merge_parent(merge_names->buf + pos);
1139 merge_names->buf[pos + hexsz] = saved;
1140 }
1141 if (!commit) {
1142 if (ptr)
1143 *ptr = '\0';
1144 die(_("not something we can merge in %s: %s"),
1145 filename, merge_names->buf + pos);
1146 }
1147 remotes = &commit_list_insert(commit, remotes)->next;
1148 }
1149
1150 if (merge_names == &fetch_head_file)
1151 strbuf_release(&fetch_head_file);
1152 }
1153
1154 static struct commit_list *collect_parents(struct commit *head_commit,
1155 int *head_subsumed,
1156 int argc, const char **argv,
1157 struct strbuf *merge_msg)
1158 {
1159 int i;
1160 struct commit_list *remoteheads = NULL;
1161 struct commit_list **remotes = &remoteheads;
1162 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1163
1164 if (merge_msg && (!have_message || shortlog_len))
1165 autogen = &merge_names;
1166
1167 if (head_commit)
1168 remotes = &commit_list_insert(head_commit, remotes)->next;
1169
1170 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1171 handle_fetch_head(remotes, autogen);
1172 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1173 } else {
1174 for (i = 0; i < argc; i++) {
1175 struct commit *commit = get_merge_parent(argv[i]);
1176 if (!commit)
1177 help_unknown_ref(argv[i], "merge",
1178 _("not something we can merge"));
1179 remotes = &commit_list_insert(commit, remotes)->next;
1180 }
1181 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1182 if (autogen) {
1183 struct commit_list *p;
1184 for (p = remoteheads; p; p = p->next)
1185 merge_name(merge_remote_util(p->item)->name, autogen);
1186 }
1187 }
1188
1189 if (autogen) {
1190 prepare_merge_message(autogen, merge_msg);
1191 strbuf_release(autogen);
1192 }
1193
1194 return remoteheads;
1195 }
1196
1197 static int merging_a_throwaway_tag(struct commit *commit)
1198 {
1199 char *tag_ref;
1200 struct object_id oid;
1201 int is_throwaway_tag = 0;
1202
1203 /* Are we merging a tag? */
1204 if (!merge_remote_util(commit) ||
1205 !merge_remote_util(commit)->obj ||
1206 merge_remote_util(commit)->obj->type != OBJ_TAG)
1207 return is_throwaway_tag;
1208
1209 /*
1210 * Now we know we are merging a tag object. Are we downstream
1211 * and following the tags from upstream? If so, we must have
1212 * the tag object pointed at by "refs/tags/$T" where $T is the
1213 * tagname recorded in the tag object. We want to allow such
1214 * a "just to catch up" merge to fast-forward.
1215 *
1216 * Otherwise, we are playing an integrator's role, making a
1217 * merge with a throw-away tag from a contributor with
1218 * something like "git pull $contributor $signed_tag".
1219 * We want to forbid such a merge from fast-forwarding
1220 * by default; otherwise we would not keep the signature
1221 * anywhere.
1222 */
1223 tag_ref = xstrfmt("refs/tags/%s",
1224 ((struct tag *)merge_remote_util(commit)->obj)->tag);
1225 if (!read_ref(tag_ref, &oid) &&
1226 oideq(&oid, &merge_remote_util(commit)->obj->oid))
1227 is_throwaway_tag = 0;
1228 else
1229 is_throwaway_tag = 1;
1230 free(tag_ref);
1231 return is_throwaway_tag;
1232 }
1233
1234 int cmd_merge(int argc, const char **argv, const char *prefix)
1235 {
1236 struct object_id result_tree, stash, head_oid;
1237 struct commit *head_commit;
1238 struct strbuf buf = STRBUF_INIT;
1239 int i, ret = 0, head_subsumed;
1240 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1241 struct commit_list *common = NULL;
1242 const char *best_strategy = NULL, *wt_strategy = NULL;
1243 struct commit_list *remoteheads, *p;
1244 void *branch_to_free;
1245 int orig_argc = argc;
1246
1247 if (argc == 2 && !strcmp(argv[1], "-h"))
1248 usage_with_options(builtin_merge_usage, builtin_merge_options);
1249
1250 /*
1251 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1252 * current branch.
1253 */
1254 branch = branch_to_free = resolve_refdup("HEAD", 0, &head_oid, NULL);
1255 if (branch)
1256 skip_prefix(branch, "refs/heads/", &branch);
1257
1258 init_diff_ui_defaults();
1259 git_config(git_merge_config, NULL);
1260
1261 if (!branch || is_null_oid(&head_oid))
1262 head_commit = NULL;
1263 else
1264 head_commit = lookup_commit_or_die(&head_oid, "HEAD");
1265
1266 if (branch_mergeoptions)
1267 parse_branch_merge_options(branch_mergeoptions);
1268 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1269 builtin_merge_usage, 0);
1270 if (shortlog_len < 0)
1271 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1272
1273 if (verbosity < 0 && show_progress == -1)
1274 show_progress = 0;
1275
1276 if (abort_current_merge) {
1277 int nargc = 2;
1278 const char *nargv[] = {"reset", "--merge", NULL};
1279
1280 if (orig_argc != 2)
1281 usage_msg_opt(_("--abort expects no arguments"),
1282 builtin_merge_usage, builtin_merge_options);
1283
1284 if (!file_exists(git_path_merge_head(the_repository)))
1285 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1286
1287 /* Invoke 'git reset --merge' */
1288 ret = cmd_reset(nargc, nargv, prefix);
1289 goto done;
1290 }
1291
1292 if (continue_current_merge) {
1293 int nargc = 1;
1294 const char *nargv[] = {"commit", NULL};
1295
1296 if (orig_argc != 2)
1297 usage_msg_opt(_("--continue expects no arguments"),
1298 builtin_merge_usage, builtin_merge_options);
1299
1300 if (!file_exists(git_path_merge_head(the_repository)))
1301 die(_("There is no merge in progress (MERGE_HEAD missing)."));
1302
1303 /* Invoke 'git commit' */
1304 ret = cmd_commit(nargc, nargv, prefix);
1305 goto done;
1306 }
1307
1308 if (read_cache_unmerged())
1309 die_resolve_conflict("merge");
1310
1311 if (file_exists(git_path_merge_head(the_repository))) {
1312 /*
1313 * There is no unmerged entry, don't advise 'git
1314 * add/rm <file>', just 'git commit'.
1315 */
1316 if (advice_resolve_conflict)
1317 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1318 "Please, commit your changes before you merge."));
1319 else
1320 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1321 }
1322 if (file_exists(git_path_cherry_pick_head(the_repository))) {
1323 if (advice_resolve_conflict)
1324 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1325 "Please, commit your changes before you merge."));
1326 else
1327 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1328 }
1329 resolve_undo_clear();
1330
1331 if (option_edit < 0)
1332 option_edit = default_edit_option();
1333
1334 cleanup_mode = get_cleanup_mode(cleanup_arg, 0 < option_edit);
1335
1336 if (verbosity < 0)
1337 show_diffstat = 0;
1338
1339 if (squash) {
1340 if (fast_forward == FF_NO)
1341 die(_("You cannot combine --squash with --no-ff."));
1342 option_commit = 0;
1343 }
1344
1345 if (!argc) {
1346 if (default_to_upstream)
1347 argc = setup_with_upstream(&argv);
1348 else
1349 die(_("No commit specified and merge.defaultToUpstream not set."));
1350 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1351 argv[0] = "@{-1}";
1352 }
1353
1354 if (!argc)
1355 usage_with_options(builtin_merge_usage,
1356 builtin_merge_options);
1357
1358 if (!head_commit) {
1359 /*
1360 * If the merged head is a valid one there is no reason
1361 * to forbid "git merge" into a branch yet to be born.
1362 * We do the same for "git pull".
1363 */
1364 struct object_id *remote_head_oid;
1365 if (squash)
1366 die(_("Squash commit into empty head not supported yet"));
1367 if (fast_forward == FF_NO)
1368 die(_("Non-fast-forward commit does not make sense into "
1369 "an empty head"));
1370 remoteheads = collect_parents(head_commit, &head_subsumed,
1371 argc, argv, NULL);
1372 if (!remoteheads)
1373 die(_("%s - not something we can merge"), argv[0]);
1374 if (remoteheads->next)
1375 die(_("Can merge only exactly one commit into empty head"));
1376
1377 if (verify_signatures)
1378 verify_merge_signature(remoteheads->item, verbosity);
1379
1380 remote_head_oid = &remoteheads->item->object.oid;
1381 read_empty(remote_head_oid, 0);
1382 update_ref("initial pull", "HEAD", remote_head_oid, NULL, 0,
1383 UPDATE_REFS_DIE_ON_ERR);
1384 goto done;
1385 }
1386
1387 /*
1388 * All the rest are the commits being merged; prepare
1389 * the standard merge summary message to be appended
1390 * to the given message.
1391 */
1392 remoteheads = collect_parents(head_commit, &head_subsumed,
1393 argc, argv, &merge_msg);
1394
1395 if (!head_commit || !argc)
1396 usage_with_options(builtin_merge_usage,
1397 builtin_merge_options);
1398
1399 if (verify_signatures) {
1400 for (p = remoteheads; p; p = p->next) {
1401 verify_merge_signature(p->item, verbosity);
1402 }
1403 }
1404
1405 strbuf_addstr(&buf, "merge");
1406 for (p = remoteheads; p; p = p->next)
1407 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1408 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1409 strbuf_reset(&buf);
1410
1411 for (p = remoteheads; p; p = p->next) {
1412 struct commit *commit = p->item;
1413 strbuf_addf(&buf, "GITHEAD_%s",
1414 oid_to_hex(&commit->object.oid));
1415 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1416 strbuf_reset(&buf);
1417 if (fast_forward != FF_ONLY && merging_a_throwaway_tag(commit))
1418 fast_forward = FF_NO;
1419 }
1420
1421 if (!use_strategies) {
1422 if (!remoteheads)
1423 ; /* already up-to-date */
1424 else if (!remoteheads->next)
1425 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1426 else
1427 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1428 }
1429
1430 for (i = 0; i < use_strategies_nr; i++) {
1431 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1432 fast_forward = FF_NO;
1433 if (use_strategies[i]->attr & NO_TRIVIAL)
1434 allow_trivial = 0;
1435 }
1436
1437 if (!remoteheads)
1438 ; /* already up-to-date */
1439 else if (!remoteheads->next)
1440 common = get_merge_bases(head_commit, remoteheads->item);
1441 else {
1442 struct commit_list *list = remoteheads;
1443 commit_list_insert(head_commit, &list);
1444 common = get_octopus_merge_bases(list);
1445 free(list);
1446 }
1447
1448 update_ref("updating ORIG_HEAD", "ORIG_HEAD",
1449 &head_commit->object.oid, NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1450
1451 if (remoteheads && !common) {
1452 /* No common ancestors found. */
1453 if (!allow_unrelated_histories)
1454 die(_("refusing to merge unrelated histories"));
1455 /* otherwise, we need a real merge. */
1456 } else if (!remoteheads ||
1457 (!remoteheads->next && !common->next &&
1458 common->item == remoteheads->item)) {
1459 /*
1460 * If head can reach all the merge then we are up to date.
1461 * but first the most common case of merging one remote.
1462 */
1463 finish_up_to_date(_("Already up to date."));
1464 goto done;
1465 } else if (fast_forward != FF_NO && !remoteheads->next &&
1466 !common->next &&
1467 oideq(&common->item->object.oid, &head_commit->object.oid)) {
1468 /* Again the most common case of merging one remote. */
1469 struct strbuf msg = STRBUF_INIT;
1470 struct commit *commit;
1471
1472 if (verbosity >= 0) {
1473 printf(_("Updating %s..%s\n"),
1474 find_unique_abbrev(&head_commit->object.oid,
1475 DEFAULT_ABBREV),
1476 find_unique_abbrev(&remoteheads->item->object.oid,
1477 DEFAULT_ABBREV));
1478 }
1479 strbuf_addstr(&msg, "Fast-forward");
1480 if (have_message)
1481 strbuf_addstr(&msg,
1482 " (no commit created; -m option ignored)");
1483 commit = remoteheads->item;
1484 if (!commit) {
1485 ret = 1;
1486 goto done;
1487 }
1488
1489 if (checkout_fast_forward(the_repository,
1490 &head_commit->object.oid,
1491 &commit->object.oid,
1492 overwrite_ignore)) {
1493 ret = 1;
1494 goto done;
1495 }
1496
1497 finish(head_commit, remoteheads, &commit->object.oid, msg.buf);
1498 drop_save();
1499 goto done;
1500 } else if (!remoteheads->next && common->next)
1501 ;
1502 /*
1503 * We are not doing octopus and not fast-forward. Need
1504 * a real merge.
1505 */
1506 else if (!remoteheads->next && !common->next && option_commit) {
1507 /*
1508 * We are not doing octopus, not fast-forward, and have
1509 * only one common.
1510 */
1511 refresh_cache(REFRESH_QUIET);
1512 if (allow_trivial && fast_forward != FF_ONLY) {
1513 /* See if it is really trivial. */
1514 git_committer_info(IDENT_STRICT);
1515 printf(_("Trying really trivial in-index merge...\n"));
1516 if (!read_tree_trivial(&common->item->object.oid,
1517 &head_commit->object.oid,
1518 &remoteheads->item->object.oid)) {
1519 ret = merge_trivial(head_commit, remoteheads);
1520 goto done;
1521 }
1522 printf(_("Nope.\n"));
1523 }
1524 } else {
1525 /*
1526 * An octopus. If we can reach all the remote we are up
1527 * to date.
1528 */
1529 int up_to_date = 1;
1530 struct commit_list *j;
1531
1532 for (j = remoteheads; j; j = j->next) {
1533 struct commit_list *common_one;
1534
1535 /*
1536 * Here we *have* to calculate the individual
1537 * merge_bases again, otherwise "git merge HEAD^
1538 * HEAD^^" would be missed.
1539 */
1540 common_one = get_merge_bases(head_commit, j->item);
1541 if (!oideq(&common_one->item->object.oid, &j->item->object.oid)) {
1542 up_to_date = 0;
1543 break;
1544 }
1545 }
1546 if (up_to_date) {
1547 finish_up_to_date(_("Already up to date. Yeeah!"));
1548 goto done;
1549 }
1550 }
1551
1552 if (fast_forward == FF_ONLY)
1553 die(_("Not possible to fast-forward, aborting."));
1554
1555 /* We are going to make a new commit. */
1556 git_committer_info(IDENT_STRICT);
1557
1558 /*
1559 * At this point, we need a real merge. No matter what strategy
1560 * we use, it would operate on the index, possibly affecting the
1561 * working tree, and when resolved cleanly, have the desired
1562 * tree in the index -- this means that the index must be in
1563 * sync with the head commit. The strategies are responsible
1564 * to ensure this.
1565 */
1566 if (use_strategies_nr == 1 ||
1567 /*
1568 * Stash away the local changes so that we can try more than one.
1569 */
1570 save_state(&stash))
1571 oidclr(&stash);
1572
1573 for (i = 0; i < use_strategies_nr; i++) {
1574 int ret;
1575 if (i) {
1576 printf(_("Rewinding the tree to pristine...\n"));
1577 restore_state(&head_commit->object.oid, &stash);
1578 }
1579 if (use_strategies_nr != 1)
1580 printf(_("Trying merge strategy %s...\n"),
1581 use_strategies[i]->name);
1582 /*
1583 * Remember which strategy left the state in the working
1584 * tree.
1585 */
1586 wt_strategy = use_strategies[i]->name;
1587
1588 ret = try_merge_strategy(use_strategies[i]->name,
1589 common, remoteheads,
1590 head_commit);
1591 if (!option_commit && !ret) {
1592 merge_was_ok = 1;
1593 /*
1594 * This is necessary here just to avoid writing
1595 * the tree, but later we will *not* exit with
1596 * status code 1 because merge_was_ok is set.
1597 */
1598 ret = 1;
1599 }
1600
1601 if (ret) {
1602 /*
1603 * The backend exits with 1 when conflicts are
1604 * left to be resolved, with 2 when it does not
1605 * handle the given merge at all.
1606 */
1607 if (ret == 1) {
1608 int cnt = evaluate_result();
1609
1610 if (best_cnt <= 0 || cnt <= best_cnt) {
1611 best_strategy = use_strategies[i]->name;
1612 best_cnt = cnt;
1613 }
1614 }
1615 if (merge_was_ok)
1616 break;
1617 else
1618 continue;
1619 }
1620
1621 /* Automerge succeeded. */
1622 write_tree_trivial(&result_tree);
1623 automerge_was_ok = 1;
1624 break;
1625 }
1626
1627 /*
1628 * If we have a resulting tree, that means the strategy module
1629 * auto resolved the merge cleanly.
1630 */
1631 if (automerge_was_ok) {
1632 ret = finish_automerge(head_commit, head_subsumed,
1633 common, remoteheads,
1634 &result_tree, wt_strategy);
1635 goto done;
1636 }
1637
1638 /*
1639 * Pick the result from the best strategy and have the user fix
1640 * it up.
1641 */
1642 if (!best_strategy) {
1643 restore_state(&head_commit->object.oid, &stash);
1644 if (use_strategies_nr > 1)
1645 fprintf(stderr,
1646 _("No merge strategy handled the merge.\n"));
1647 else
1648 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1649 use_strategies[0]->name);
1650 ret = 2;
1651 goto done;
1652 } else if (best_strategy == wt_strategy)
1653 ; /* We already have its result in the working tree. */
1654 else {
1655 printf(_("Rewinding the tree to pristine...\n"));
1656 restore_state(&head_commit->object.oid, &stash);
1657 printf(_("Using the %s to prepare resolving by hand.\n"),
1658 best_strategy);
1659 try_merge_strategy(best_strategy, common, remoteheads,
1660 head_commit);
1661 }
1662
1663 if (squash)
1664 finish(head_commit, remoteheads, NULL, NULL);
1665 else
1666 write_merge_state(remoteheads);
1667
1668 if (merge_was_ok)
1669 fprintf(stderr, _("Automatic merge went well; "
1670 "stopped before committing as requested\n"));
1671 else
1672 ret = suggest_conflicts();
1673
1674 done:
1675 free(branch_to_free);
1676 return ret;
1677 }