Make non-static functions, that may be static, static
[git/dscho.git] / builtin-merge.c
blobe78fa18b3a68e2b7f041beab0524ce1a2b7e9365
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  */
9 #include "cache.h"
10 #include "parse-options.h"
11 #include "builtin.h"
12 #include "run-command.h"
13 #include "diff.h"
14 #include "refs.h"
15 #include "commit.h"
16 #include "diffcore.h"
17 #include "revision.h"
18 #include "unpack-trees.h"
19 #include "cache-tree.h"
20 #include "dir.h"
21 #include "utf8.h"
22 #include "log-tree.h"
23 #include "color.h"
24 #include "rerere.h"
26 #define DEFAULT_TWOHEAD (1<<0)
27 #define DEFAULT_OCTOPUS (1<<1)
28 #define NO_FAST_FORWARD (1<<2)
29 #define NO_TRIVIAL      (1<<3)
31 struct strategy {
32         const char *name;
33         unsigned attr;
36 static const char * const builtin_merge_usage[] = {
37         "git-merge [options] <remote>...",
38         "git-merge [options] <msg> HEAD <remote>",
39         NULL
42 static int show_diffstat = 1, option_log, squash;
43 static int option_commit = 1, allow_fast_forward = 1;
44 static int allow_trivial = 1, have_message;
45 static struct strbuf merge_msg;
46 static struct commit_list *remoteheads;
47 static unsigned char head[20], stash[20];
48 static struct strategy **use_strategies;
49 static size_t use_strategies_nr, use_strategies_alloc;
50 static const char *branch;
52 static struct strategy all_strategy[] = {
53         { "recursive",  DEFAULT_TWOHEAD | NO_TRIVIAL },
54         { "octopus",    DEFAULT_OCTOPUS },
55         { "resolve",    0 },
56         { "ours",       NO_FAST_FORWARD | NO_TRIVIAL },
57         { "subtree",    NO_FAST_FORWARD | NO_TRIVIAL },
60 static const char *pull_twohead, *pull_octopus;
62 static int option_parse_message(const struct option *opt,
63                                 const char *arg, int unset)
65         struct strbuf *buf = opt->value;
67         if (unset)
68                 strbuf_setlen(buf, 0);
69         else if (arg) {
70                 strbuf_addf(buf, "%s\n\n", arg);
71                 have_message = 1;
72         } else
73                 return error("switch `m' requires a value");
74         return 0;
77 static struct strategy *get_strategy(const char *name)
79         int i;
80         struct strbuf err;
82         if (!name)
83                 return NULL;
85         for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
86                 if (!strcmp(name, all_strategy[i].name))
87                         return &all_strategy[i];
89         strbuf_init(&err, 0);
90         for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
91                 strbuf_addf(&err, " %s", all_strategy[i].name);
92         fprintf(stderr, "Could not find merge strategy '%s'.\n", name);
93         fprintf(stderr, "Available strategies are:%s.\n", err.buf);
94         exit(1);
97 static void append_strategy(struct strategy *s)
99         ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
100         use_strategies[use_strategies_nr++] = s;
103 static int option_parse_strategy(const struct option *opt,
104                                  const char *name, int unset)
106         if (unset)
107                 return 0;
109         append_strategy(get_strategy(name));
110         return 0;
113 static int option_parse_n(const struct option *opt,
114                           const char *arg, int unset)
116         show_diffstat = unset;
117         return 0;
120 static struct option builtin_merge_options[] = {
121         { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
122                 "do not show a diffstat at the end of the merge",
123                 PARSE_OPT_NOARG, option_parse_n },
124         OPT_BOOLEAN(0, "stat", &show_diffstat,
125                 "show a diffstat at the end of the merge"),
126         OPT_BOOLEAN(0, "summary", &show_diffstat, "(synonym to --stat)"),
127         OPT_BOOLEAN(0, "log", &option_log,
128                 "add list of one-line log to merge commit message"),
129         OPT_BOOLEAN(0, "squash", &squash,
130                 "create a single commit instead of doing a merge"),
131         OPT_BOOLEAN(0, "commit", &option_commit,
132                 "perform a commit if the merge succeeds (default)"),
133         OPT_BOOLEAN(0, "ff", &allow_fast_forward,
134                 "allow fast forward (default)"),
135         OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
136                 "merge strategy to use", option_parse_strategy),
137         OPT_CALLBACK('m', "message", &merge_msg, "message",
138                 "message to be used for the merge commit (if any)",
139                 option_parse_message),
140         OPT_END()
143 /* Cleans up metadata that is uninteresting after a succeeded merge. */
144 static void drop_save(void)
146         unlink(git_path("MERGE_HEAD"));
147         unlink(git_path("MERGE_MSG"));
150 static void save_state(void)
152         int len;
153         struct child_process cp;
154         struct strbuf buffer = STRBUF_INIT;
155         const char *argv[] = {"stash", "create", NULL};
157         memset(&cp, 0, sizeof(cp));
158         cp.argv = argv;
159         cp.out = -1;
160         cp.git_cmd = 1;
162         if (start_command(&cp))
163                 die("could not run stash.");
164         len = strbuf_read(&buffer, cp.out, 1024);
165         close(cp.out);
167         if (finish_command(&cp) || len < 0)
168                 die("stash failed");
169         else if (!len)
170                 return;
171         strbuf_setlen(&buffer, buffer.len-1);
172         if (get_sha1(buffer.buf, stash))
173                 die("not a valid object: %s", buffer.buf);
176 static void reset_hard(unsigned const char *sha1, int verbose)
178         int i = 0;
179         const char *args[6];
181         args[i++] = "read-tree";
182         if (verbose)
183                 args[i++] = "-v";
184         args[i++] = "--reset";
185         args[i++] = "-u";
186         args[i++] = sha1_to_hex(sha1);
187         args[i] = NULL;
189         if (run_command_v_opt(args, RUN_GIT_CMD))
190                 die("read-tree failed");
193 static void restore_state(void)
195         struct strbuf sb;
196         const char *args[] = { "stash", "apply", NULL, NULL };
198         if (is_null_sha1(stash))
199                 return;
201         reset_hard(head, 1);
203         strbuf_init(&sb, 0);
204         args[2] = sha1_to_hex(stash);
206         /*
207          * It is OK to ignore error here, for example when there was
208          * nothing to restore.
209          */
210         run_command_v_opt(args, RUN_GIT_CMD);
212         strbuf_release(&sb);
213         refresh_cache(REFRESH_QUIET);
216 /* This is called when no merge was necessary. */
217 static void finish_up_to_date(const char *msg)
219         printf("%s%s\n", squash ? " (nothing to squash)" : "", msg);
220         drop_save();
223 static void squash_message(void)
225         struct rev_info rev;
226         struct commit *commit;
227         struct strbuf out;
228         struct commit_list *j;
229         int fd;
231         printf("Squash commit -- not updating HEAD\n");
232         fd = open(git_path("SQUASH_MSG"), O_WRONLY | O_CREAT, 0666);
233         if (fd < 0)
234                 die("Could not write to %s", git_path("SQUASH_MSG"));
236         init_revisions(&rev, NULL);
237         rev.ignore_merges = 1;
238         rev.commit_format = CMIT_FMT_MEDIUM;
240         commit = lookup_commit(head);
241         commit->object.flags |= UNINTERESTING;
242         add_pending_object(&rev, &commit->object, NULL);
244         for (j = remoteheads; j; j = j->next)
245                 add_pending_object(&rev, &j->item->object, NULL);
247         setup_revisions(0, NULL, &rev, NULL);
248         if (prepare_revision_walk(&rev))
249                 die("revision walk setup failed");
251         strbuf_init(&out, 0);
252         strbuf_addstr(&out, "Squashed commit of the following:\n");
253         while ((commit = get_revision(&rev)) != NULL) {
254                 strbuf_addch(&out, '\n');
255                 strbuf_addf(&out, "commit %s\n",
256                         sha1_to_hex(commit->object.sha1));
257                 pretty_print_commit(rev.commit_format, commit, &out, rev.abbrev,
258                         NULL, NULL, rev.date_mode, 0);
259         }
260         write(fd, out.buf, out.len);
261         close(fd);
262         strbuf_release(&out);
265 static int run_hook(const char *name)
267         struct child_process hook;
268         const char *argv[3], *env[2];
269         char index[PATH_MAX];
271         argv[0] = git_path("hooks/%s", name);
272         if (access(argv[0], X_OK) < 0)
273                 return 0;
275         snprintf(index, sizeof(index), "GIT_INDEX_FILE=%s", get_index_file());
276         env[0] = index;
277         env[1] = NULL;
279         if (squash)
280                 argv[1] = "1";
281         else
282                 argv[1] = "0";
283         argv[2] = NULL;
285         memset(&hook, 0, sizeof(hook));
286         hook.argv = argv;
287         hook.no_stdin = 1;
288         hook.stdout_to_stderr = 1;
289         hook.env = env;
291         return run_command(&hook);
294 static void finish(const unsigned char *new_head, const char *msg)
296         struct strbuf reflog_message;
298         strbuf_init(&reflog_message, 0);
299         if (!msg)
300                 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
301         else {
302                 printf("%s\n", msg);
303                 strbuf_addf(&reflog_message, "%s: %s",
304                         getenv("GIT_REFLOG_ACTION"), msg);
305         }
306         if (squash) {
307                 squash_message();
308         } else {
309                 if (!merge_msg.len)
310                         printf("No merge message -- not updating HEAD\n");
311                 else {
312                         const char *argv_gc_auto[] = { "gc", "--auto", NULL };
313                         update_ref(reflog_message.buf, "HEAD",
314                                 new_head, head, 0,
315                                 DIE_ON_ERR);
316                         /*
317                          * We ignore errors in 'gc --auto', since the
318                          * user should see them.
319                          */
320                         run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
321                 }
322         }
323         if (new_head && show_diffstat) {
324                 struct diff_options opts;
325                 diff_setup(&opts);
326                 opts.output_format |=
327                         DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
328                 opts.detect_rename = DIFF_DETECT_RENAME;
329                 if (diff_use_color_default > 0)
330                         DIFF_OPT_SET(&opts, COLOR_DIFF);
331                 if (diff_setup_done(&opts) < 0)
332                         die("diff_setup_done failed");
333                 diff_tree_sha1(head, new_head, "", &opts);
334                 diffcore_std(&opts);
335                 diff_flush(&opts);
336         }
338         /* Run a post-merge hook */
339         run_hook("post-merge");
341         strbuf_release(&reflog_message);
344 /* Get the name for the merge commit's message. */
345 static void merge_name(const char *remote, struct strbuf *msg)
347         struct object *remote_head;
348         unsigned char branch_head[20], buf_sha[20];
349         struct strbuf buf;
350         const char *ptr;
351         int len, early;
353         memset(branch_head, 0, sizeof(branch_head));
354         remote_head = peel_to_type(remote, 0, NULL, OBJ_COMMIT);
355         if (!remote_head)
356                 die("'%s' does not point to a commit", remote);
358         strbuf_init(&buf, 0);
359         strbuf_addstr(&buf, "refs/heads/");
360         strbuf_addstr(&buf, remote);
361         resolve_ref(buf.buf, branch_head, 0, 0);
363         if (!hashcmp(remote_head->sha1, branch_head)) {
364                 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
365                         sha1_to_hex(branch_head), remote);
366                 return;
367         }
369         /* See if remote matches <name>^^^.. or <name>~<number> */
370         for (len = 0, ptr = remote + strlen(remote);
371              remote < ptr && ptr[-1] == '^';
372              ptr--)
373                 len++;
374         if (len)
375                 early = 1;
376         else {
377                 early = 0;
378                 ptr = strrchr(remote, '~');
379                 if (ptr) {
380                         int seen_nonzero = 0;
382                         len++; /* count ~ */
383                         while (*++ptr && isdigit(*ptr)) {
384                                 seen_nonzero |= (*ptr != '0');
385                                 len++;
386                         }
387                         if (*ptr)
388                                 len = 0; /* not ...~<number> */
389                         else if (seen_nonzero)
390                                 early = 1;
391                         else if (len == 1)
392                                 early = 1; /* "name~" is "name~1"! */
393                 }
394         }
395         if (len) {
396                 struct strbuf truname = STRBUF_INIT;
397                 strbuf_addstr(&truname, "refs/heads/");
398                 strbuf_addstr(&truname, remote);
399                 strbuf_setlen(&truname, len+11);
400                 if (resolve_ref(truname.buf, buf_sha, 0, 0)) {
401                         strbuf_addf(msg,
402                                     "%s\t\tbranch '%s'%s of .\n",
403                                     sha1_to_hex(remote_head->sha1),
404                                     truname.buf,
405                                     (early ? " (early part)" : ""));
406                         return;
407                 }
408         }
410         if (!strcmp(remote, "FETCH_HEAD") &&
411                         !access(git_path("FETCH_HEAD"), R_OK)) {
412                 FILE *fp;
413                 struct strbuf line;
414                 char *ptr;
416                 strbuf_init(&line, 0);
417                 fp = fopen(git_path("FETCH_HEAD"), "r");
418                 if (!fp)
419                         die("could not open %s for reading: %s",
420                                 git_path("FETCH_HEAD"), strerror(errno));
421                 strbuf_getline(&line, fp, '\n');
422                 fclose(fp);
423                 ptr = strstr(line.buf, "\tnot-for-merge\t");
424                 if (ptr)
425                         strbuf_remove(&line, ptr-line.buf+1, 13);
426                 strbuf_addbuf(msg, &line);
427                 strbuf_release(&line);
428                 return;
429         }
430         strbuf_addf(msg, "%s\t\tcommit '%s'\n",
431                 sha1_to_hex(remote_head->sha1), remote);
434 static int git_merge_config(const char *k, const char *v, void *cb)
436         if (branch && !prefixcmp(k, "branch.") &&
437                 !prefixcmp(k + 7, branch) &&
438                 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
439                 const char **argv;
440                 int argc;
441                 char *buf;
443                 buf = xstrdup(v);
444                 argc = split_cmdline(buf, &argv);
445                 argv = xrealloc(argv, sizeof(*argv) * (argc + 2));
446                 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
447                 argc++;
448                 parse_options(argc, argv, builtin_merge_options,
449                               builtin_merge_usage, 0);
450                 free(buf);
451         }
453         if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
454                 show_diffstat = git_config_bool(k, v);
455         else if (!strcmp(k, "pull.twohead"))
456                 return git_config_string(&pull_twohead, k, v);
457         else if (!strcmp(k, "pull.octopus"))
458                 return git_config_string(&pull_octopus, k, v);
459         else if (!strcmp(k, "merge.log") || !strcmp(k, "merge.summary"))
460                 option_log = git_config_bool(k, v);
461         return git_diff_ui_config(k, v, cb);
464 static int read_tree_trivial(unsigned char *common, unsigned char *head,
465                              unsigned char *one)
467         int i, nr_trees = 0;
468         struct tree *trees[MAX_UNPACK_TREES];
469         struct tree_desc t[MAX_UNPACK_TREES];
470         struct unpack_trees_options opts;
472         memset(&opts, 0, sizeof(opts));
473         opts.head_idx = 2;
474         opts.src_index = &the_index;
475         opts.dst_index = &the_index;
476         opts.update = 1;
477         opts.verbose_update = 1;
478         opts.trivial_merges_only = 1;
479         opts.merge = 1;
480         trees[nr_trees] = parse_tree_indirect(common);
481         if (!trees[nr_trees++])
482                 return -1;
483         trees[nr_trees] = parse_tree_indirect(head);
484         if (!trees[nr_trees++])
485                 return -1;
486         trees[nr_trees] = parse_tree_indirect(one);
487         if (!trees[nr_trees++])
488                 return -1;
489         opts.fn = threeway_merge;
490         cache_tree_free(&active_cache_tree);
491         for (i = 0; i < nr_trees; i++) {
492                 parse_tree(trees[i]);
493                 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
494         }
495         if (unpack_trees(nr_trees, t, &opts))
496                 return -1;
497         return 0;
500 static void write_tree_trivial(unsigned char *sha1)
502         if (write_cache_as_tree(sha1, 0, NULL))
503                 die("git write-tree failed to write a tree");
506 static int try_merge_strategy(const char *strategy, struct commit_list *common,
507                               const char *head_arg)
509         const char **args;
510         int i = 0, ret;
511         struct commit_list *j;
512         struct strbuf buf;
514         args = xmalloc((4 + commit_list_count(common) +
515                         commit_list_count(remoteheads)) * sizeof(char *));
516         strbuf_init(&buf, 0);
517         strbuf_addf(&buf, "merge-%s", strategy);
518         args[i++] = buf.buf;
519         for (j = common; j; j = j->next)
520                 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
521         args[i++] = "--";
522         args[i++] = head_arg;
523         for (j = remoteheads; j; j = j->next)
524                 args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
525         args[i] = NULL;
526         ret = run_command_v_opt(args, RUN_GIT_CMD);
527         strbuf_release(&buf);
528         i = 1;
529         for (j = common; j; j = j->next)
530                 free((void *)args[i++]);
531         i += 2;
532         for (j = remoteheads; j; j = j->next)
533                 free((void *)args[i++]);
534         free(args);
535         return -ret;
538 static void count_diff_files(struct diff_queue_struct *q,
539                              struct diff_options *opt, void *data)
541         int *count = data;
543         (*count) += q->nr;
546 static int count_unmerged_entries(void)
548         const struct index_state *state = &the_index;
549         int i, ret = 0;
551         for (i = 0; i < state->cache_nr; i++)
552                 if (ce_stage(state->cache[i]))
553                         ret++;
555         return ret;
558 static int checkout_fast_forward(unsigned char *head, unsigned char *remote)
560         struct tree *trees[MAX_UNPACK_TREES];
561         struct unpack_trees_options opts;
562         struct tree_desc t[MAX_UNPACK_TREES];
563         int i, fd, nr_trees = 0;
564         struct dir_struct dir;
565         struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
567         if (read_cache_unmerged())
568                 die("you need to resolve your current index first");
570         fd = hold_locked_index(lock_file, 1);
572         memset(&trees, 0, sizeof(trees));
573         memset(&opts, 0, sizeof(opts));
574         memset(&t, 0, sizeof(t));
575         memset(&dir, 0, sizeof(dir));
576         dir.show_ignored = 1;
577         dir.exclude_per_dir = ".gitignore";
578         opts.dir = &dir;
580         opts.head_idx = 1;
581         opts.src_index = &the_index;
582         opts.dst_index = &the_index;
583         opts.update = 1;
584         opts.verbose_update = 1;
585         opts.merge = 1;
586         opts.fn = twoway_merge;
588         trees[nr_trees] = parse_tree_indirect(head);
589         if (!trees[nr_trees++])
590                 return -1;
591         trees[nr_trees] = parse_tree_indirect(remote);
592         if (!trees[nr_trees++])
593                 return -1;
594         for (i = 0; i < nr_trees; i++) {
595                 parse_tree(trees[i]);
596                 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
597         }
598         if (unpack_trees(nr_trees, t, &opts))
599                 return -1;
600         if (write_cache(fd, active_cache, active_nr) ||
601                 commit_locked_index(lock_file))
602                 die("unable to write new index file");
603         return 0;
606 static void split_merge_strategies(const char *string, struct strategy **list,
607                                    int *nr, int *alloc)
609         char *p, *q, *buf;
611         if (!string)
612                 return;
614         buf = xstrdup(string);
615         q = buf;
616         for (;;) {
617                 p = strchr(q, ' ');
618                 if (!p) {
619                         ALLOC_GROW(*list, *nr + 1, *alloc);
620                         (*list)[(*nr)++].name = xstrdup(q);
621                         free(buf);
622                         return;
623                 } else {
624                         *p = '\0';
625                         ALLOC_GROW(*list, *nr + 1, *alloc);
626                         (*list)[(*nr)++].name = xstrdup(q);
627                         q = ++p;
628                 }
629         }
632 static void add_strategies(const char *string, unsigned attr)
634         struct strategy *list = NULL;
635         int list_alloc = 0, list_nr = 0, i;
637         memset(&list, 0, sizeof(list));
638         split_merge_strategies(string, &list, &list_nr, &list_alloc);
639         if (list) {
640                 for (i = 0; i < list_nr; i++)
641                         append_strategy(get_strategy(list[i].name));
642                 return;
643         }
644         for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
645                 if (all_strategy[i].attr & attr)
646                         append_strategy(&all_strategy[i]);
650 static int merge_trivial(void)
652         unsigned char result_tree[20], result_commit[20];
653         struct commit_list parent;
655         write_tree_trivial(result_tree);
656         printf("Wonderful.\n");
657         parent.item = remoteheads->item;
658         parent.next = NULL;
659         commit_tree(merge_msg.buf, result_tree, &parent, result_commit);
660         finish(result_commit, "In-index merge");
661         drop_save();
662         return 0;
665 static int finish_automerge(struct commit_list *common,
666                             unsigned char *result_tree,
667                             const char *wt_strategy)
669         struct commit_list *parents = NULL, *j;
670         struct strbuf buf = STRBUF_INIT;
671         unsigned char result_commit[20];
673         free_commit_list(common);
674         if (allow_fast_forward) {
675                 parents = remoteheads;
676                 commit_list_insert(lookup_commit(head), &parents);
677                 parents = reduce_heads(parents);
678         } else {
679                 struct commit_list **pptr = &parents;
681                 pptr = &commit_list_insert(lookup_commit(head),
682                                 pptr)->next;
683                 for (j = remoteheads; j; j = j->next)
684                         pptr = &commit_list_insert(j->item, pptr)->next;
685         }
686         free_commit_list(remoteheads);
687         strbuf_addch(&merge_msg, '\n');
688         commit_tree(merge_msg.buf, result_tree, parents, result_commit);
689         strbuf_addf(&buf, "Merge made by %s.", wt_strategy);
690         finish(result_commit, buf.buf);
691         strbuf_release(&buf);
692         drop_save();
693         return 0;
696 static int suggest_conflicts(void)
698         FILE *fp;
699         int pos;
701         fp = fopen(git_path("MERGE_MSG"), "a");
702         if (!fp)
703                 die("Could open %s for writing", git_path("MERGE_MSG"));
704         fprintf(fp, "\nConflicts:\n");
705         for (pos = 0; pos < active_nr; pos++) {
706                 struct cache_entry *ce = active_cache[pos];
708                 if (ce_stage(ce)) {
709                         fprintf(fp, "\t%s\n", ce->name);
710                         while (pos + 1 < active_nr &&
711                                         !strcmp(ce->name,
712                                                 active_cache[pos + 1]->name))
713                                 pos++;
714                 }
715         }
716         fclose(fp);
717         rerere();
718         printf("Automatic merge failed; "
719                         "fix conflicts and then commit the result.\n");
720         return 1;
723 static struct commit *is_old_style_invocation(int argc, const char **argv)
725         struct commit *second_token = NULL;
726         if (argc > 1) {
727                 unsigned char second_sha1[20];
729                 if (get_sha1(argv[1], second_sha1))
730                         return NULL;
731                 second_token = lookup_commit_reference_gently(second_sha1, 0);
732                 if (!second_token)
733                         die("'%s' is not a commit", argv[1]);
734                 if (hashcmp(second_token->object.sha1, head))
735                         return NULL;
736         }
737         return second_token;
740 static int evaluate_result(void)
742         int cnt = 0;
743         struct rev_info rev;
745         if (read_cache() < 0)
746                 die("failed to read the cache");
748         /* Check how many files differ. */
749         init_revisions(&rev, "");
750         setup_revisions(0, NULL, &rev, NULL);
751         rev.diffopt.output_format |=
752                 DIFF_FORMAT_CALLBACK;
753         rev.diffopt.format_callback = count_diff_files;
754         rev.diffopt.format_callback_data = &cnt;
755         run_diff_files(&rev, 0);
757         /*
758          * Check how many unmerged entries are
759          * there.
760          */
761         cnt += count_unmerged_entries();
763         return cnt;
766 int cmd_merge(int argc, const char **argv, const char *prefix)
768         unsigned char result_tree[20];
769         struct strbuf buf;
770         const char *head_arg;
771         int flag, head_invalid = 0, i;
772         int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
773         struct commit_list *common = NULL;
774         const char *best_strategy = NULL, *wt_strategy = NULL;
775         struct commit_list **remotes = &remoteheads;
777         setup_work_tree();
778         if (unmerged_cache())
779                 die("You are in the middle of a conflicted merge.");
781         /*
782          * Check if we are _not_ on a detached HEAD, i.e. if there is a
783          * current branch.
784          */
785         branch = resolve_ref("HEAD", head, 0, &flag);
786         if (branch && !prefixcmp(branch, "refs/heads/"))
787                 branch += 11;
788         if (is_null_sha1(head))
789                 head_invalid = 1;
791         git_config(git_merge_config, NULL);
793         /* for color.ui */
794         if (diff_use_color_default == -1)
795                 diff_use_color_default = git_use_color_default;
797         argc = parse_options(argc, argv, builtin_merge_options,
798                         builtin_merge_usage, 0);
800         if (squash) {
801                 if (!allow_fast_forward)
802                         die("You cannot combine --squash with --no-ff.");
803                 option_commit = 0;
804         }
806         if (!argc)
807                 usage_with_options(builtin_merge_usage,
808                         builtin_merge_options);
810         /*
811          * This could be traditional "merge <msg> HEAD <commit>..."  and
812          * the way we can tell it is to see if the second token is HEAD,
813          * but some people might have misused the interface and used a
814          * committish that is the same as HEAD there instead.
815          * Traditional format never would have "-m" so it is an
816          * additional safety measure to check for it.
817          */
818         strbuf_init(&buf, 0);
820         if (!have_message && is_old_style_invocation(argc, argv)) {
821                 strbuf_addstr(&merge_msg, argv[0]);
822                 head_arg = argv[1];
823                 argv += 2;
824                 argc -= 2;
825         } else if (head_invalid) {
826                 struct object *remote_head;
827                 /*
828                  * If the merged head is a valid one there is no reason
829                  * to forbid "git merge" into a branch yet to be born.
830                  * We do the same for "git pull".
831                  */
832                 if (argc != 1)
833                         die("Can merge only exactly one commit into "
834                                 "empty head");
835                 remote_head = peel_to_type(argv[0], 0, NULL, OBJ_COMMIT);
836                 if (!remote_head)
837                         die("%s - not something we can merge", argv[0]);
838                 update_ref("initial pull", "HEAD", remote_head->sha1, NULL, 0,
839                                 DIE_ON_ERR);
840                 reset_hard(remote_head->sha1, 0);
841                 return 0;
842         } else {
843                 struct strbuf msg;
845                 /* We are invoked directly as the first-class UI. */
846                 head_arg = "HEAD";
848                 /*
849                  * All the rest are the commits being merged;
850                  * prepare the standard merge summary message to
851                  * be appended to the given message.  If remote
852                  * is invalid we will die later in the common
853                  * codepath so we discard the error in this
854                  * loop.
855                  */
856                 strbuf_init(&msg, 0);
857                 for (i = 0; i < argc; i++)
858                         merge_name(argv[i], &msg);
859                 fmt_merge_msg(option_log, &msg, &merge_msg);
860                 if (merge_msg.len)
861                         strbuf_setlen(&merge_msg, merge_msg.len-1);
862         }
864         if (head_invalid || !argc)
865                 usage_with_options(builtin_merge_usage,
866                         builtin_merge_options);
868         strbuf_addstr(&buf, "merge");
869         for (i = 0; i < argc; i++)
870                 strbuf_addf(&buf, " %s", argv[i]);
871         setenv("GIT_REFLOG_ACTION", buf.buf, 0);
872         strbuf_reset(&buf);
874         for (i = 0; i < argc; i++) {
875                 struct object *o;
877                 o = peel_to_type(argv[i], 0, NULL, OBJ_COMMIT);
878                 if (!o)
879                         die("%s - not something we can merge", argv[i]);
880                 remotes = &commit_list_insert(lookup_commit(o->sha1),
881                         remotes)->next;
883                 strbuf_addf(&buf, "GITHEAD_%s", sha1_to_hex(o->sha1));
884                 setenv(buf.buf, argv[i], 1);
885                 strbuf_reset(&buf);
886         }
888         if (!use_strategies) {
889                 if (!remoteheads->next)
890                         add_strategies(pull_twohead, DEFAULT_TWOHEAD);
891                 else
892                         add_strategies(pull_octopus, DEFAULT_OCTOPUS);
893         }
895         for (i = 0; i < use_strategies_nr; i++) {
896                 if (use_strategies[i]->attr & NO_FAST_FORWARD)
897                         allow_fast_forward = 0;
898                 if (use_strategies[i]->attr & NO_TRIVIAL)
899                         allow_trivial = 0;
900         }
902         if (!remoteheads->next)
903                 common = get_merge_bases(lookup_commit(head),
904                                 remoteheads->item, 1);
905         else {
906                 struct commit_list *list = remoteheads;
907                 commit_list_insert(lookup_commit(head), &list);
908                 common = get_octopus_merge_bases(list);
909                 free(list);
910         }
912         update_ref("updating ORIG_HEAD", "ORIG_HEAD", head, NULL, 0,
913                 DIE_ON_ERR);
915         if (!common)
916                 ; /* No common ancestors found. We need a real merge. */
917         else if (!remoteheads->next && !common->next &&
918                         common->item == remoteheads->item) {
919                 /*
920                  * If head can reach all the merge then we are up to date.
921                  * but first the most common case of merging one remote.
922                  */
923                 finish_up_to_date("Already up-to-date.");
924                 return 0;
925         } else if (allow_fast_forward && !remoteheads->next &&
926                         !common->next &&
927                         !hashcmp(common->item->object.sha1, head)) {
928                 /* Again the most common case of merging one remote. */
929                 struct strbuf msg;
930                 struct object *o;
931                 char hex[41];
933                 strcpy(hex, find_unique_abbrev(head, DEFAULT_ABBREV));
935                 printf("Updating %s..%s\n",
936                         hex,
937                         find_unique_abbrev(remoteheads->item->object.sha1,
938                         DEFAULT_ABBREV));
939                 refresh_cache(REFRESH_QUIET);
940                 strbuf_init(&msg, 0);
941                 strbuf_addstr(&msg, "Fast forward");
942                 if (have_message)
943                         strbuf_addstr(&msg,
944                                 " (no commit created; -m option ignored)");
945                 o = peel_to_type(sha1_to_hex(remoteheads->item->object.sha1),
946                         0, NULL, OBJ_COMMIT);
947                 if (!o)
948                         return 1;
950                 if (checkout_fast_forward(head, remoteheads->item->object.sha1))
951                         return 1;
953                 finish(o->sha1, msg.buf);
954                 drop_save();
955                 return 0;
956         } else if (!remoteheads->next && common->next)
957                 ;
958                 /*
959                  * We are not doing octopus and not fast forward.  Need
960                  * a real merge.
961                  */
962         else if (!remoteheads->next && !common->next && option_commit) {
963                 /*
964                  * We are not doing octopus, not fast forward, and have
965                  * only one common.
966                  */
967                 refresh_cache(REFRESH_QUIET);
968                 if (allow_trivial) {
969                         /* See if it is really trivial. */
970                         git_committer_info(IDENT_ERROR_ON_NO_NAME);
971                         printf("Trying really trivial in-index merge...\n");
972                         if (!read_tree_trivial(common->item->object.sha1,
973                                         head, remoteheads->item->object.sha1))
974                                 return merge_trivial();
975                         printf("Nope.\n");
976                 }
977         } else {
978                 /*
979                  * An octopus.  If we can reach all the remote we are up
980                  * to date.
981                  */
982                 int up_to_date = 1;
983                 struct commit_list *j;
985                 for (j = remoteheads; j; j = j->next) {
986                         struct commit_list *common_one;
988                         /*
989                          * Here we *have* to calculate the individual
990                          * merge_bases again, otherwise "git merge HEAD^
991                          * HEAD^^" would be missed.
992                          */
993                         common_one = get_merge_bases(lookup_commit(head),
994                                 j->item, 1);
995                         if (hashcmp(common_one->item->object.sha1,
996                                 j->item->object.sha1)) {
997                                 up_to_date = 0;
998                                 break;
999                         }
1000                 }
1001                 if (up_to_date) {
1002                         finish_up_to_date("Already up-to-date. Yeeah!");
1003                         return 0;
1004                 }
1005         }
1007         /* We are going to make a new commit. */
1008         git_committer_info(IDENT_ERROR_ON_NO_NAME);
1010         /*
1011          * At this point, we need a real merge.  No matter what strategy
1012          * we use, it would operate on the index, possibly affecting the
1013          * working tree, and when resolved cleanly, have the desired
1014          * tree in the index -- this means that the index must be in
1015          * sync with the head commit.  The strategies are responsible
1016          * to ensure this.
1017          */
1018         if (use_strategies_nr != 1) {
1019                 /*
1020                  * Stash away the local changes so that we can try more
1021                  * than one.
1022                  */
1023                 save_state();
1024         } else {
1025                 memcpy(stash, null_sha1, 20);
1026         }
1028         for (i = 0; i < use_strategies_nr; i++) {
1029                 int ret;
1030                 if (i) {
1031                         printf("Rewinding the tree to pristine...\n");
1032                         restore_state();
1033                 }
1034                 if (use_strategies_nr != 1)
1035                         printf("Trying merge strategy %s...\n",
1036                                 use_strategies[i]->name);
1037                 /*
1038                  * Remember which strategy left the state in the working
1039                  * tree.
1040                  */
1041                 wt_strategy = use_strategies[i]->name;
1043                 ret = try_merge_strategy(use_strategies[i]->name,
1044                         common, head_arg);
1045                 if (!option_commit && !ret) {
1046                         merge_was_ok = 1;
1047                         /*
1048                          * This is necessary here just to avoid writing
1049                          * the tree, but later we will *not* exit with
1050                          * status code 1 because merge_was_ok is set.
1051                          */
1052                         ret = 1;
1053                 }
1055                 if (ret) {
1056                         /*
1057                          * The backend exits with 1 when conflicts are
1058                          * left to be resolved, with 2 when it does not
1059                          * handle the given merge at all.
1060                          */
1061                         if (ret == 1) {
1062                                 int cnt = evaluate_result();
1064                                 if (best_cnt <= 0 || cnt <= best_cnt) {
1065                                         best_strategy = use_strategies[i]->name;
1066                                         best_cnt = cnt;
1067                                 }
1068                         }
1069                         if (merge_was_ok)
1070                                 break;
1071                         else
1072                                 continue;
1073                 }
1075                 /* Automerge succeeded. */
1076                 write_tree_trivial(result_tree);
1077                 automerge_was_ok = 1;
1078                 break;
1079         }
1081         /*
1082          * If we have a resulting tree, that means the strategy module
1083          * auto resolved the merge cleanly.
1084          */
1085         if (automerge_was_ok)
1086                 return finish_automerge(common, result_tree, wt_strategy);
1088         /*
1089          * Pick the result from the best strategy and have the user fix
1090          * it up.
1091          */
1092         if (!best_strategy) {
1093                 restore_state();
1094                 if (use_strategies_nr > 1)
1095                         fprintf(stderr,
1096                                 "No merge strategy handled the merge.\n");
1097                 else
1098                         fprintf(stderr, "Merge with strategy %s failed.\n",
1099                                 use_strategies[0]->name);
1100                 return 2;
1101         } else if (best_strategy == wt_strategy)
1102                 ; /* We already have its result in the working tree. */
1103         else {
1104                 printf("Rewinding the tree to pristine...\n");
1105                 restore_state();
1106                 printf("Using the %s to prepare resolving by hand.\n",
1107                         best_strategy);
1108                 try_merge_strategy(best_strategy, common, head_arg);
1109         }
1111         if (squash)
1112                 finish(NULL, NULL);
1113         else {
1114                 int fd;
1115                 struct commit_list *j;
1117                 for (j = remoteheads; j; j = j->next)
1118                         strbuf_addf(&buf, "%s\n",
1119                                 sha1_to_hex(j->item->object.sha1));
1120                 fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
1121                 if (fd < 0)
1122                         die("Could open %s for writing",
1123                                 git_path("MERGE_HEAD"));
1124                 if (write_in_full(fd, buf.buf, buf.len) != buf.len)
1125                         die("Could not write to %s", git_path("MERGE_HEAD"));
1126                 close(fd);
1127                 strbuf_addch(&merge_msg, '\n');
1128                 fd = open(git_path("MERGE_MSG"), O_WRONLY | O_CREAT, 0666);
1129                 if (fd < 0)
1130                         die("Could open %s for writing", git_path("MERGE_MSG"));
1131                 if (write_in_full(fd, merge_msg.buf, merge_msg.len) !=
1132                         merge_msg.len)
1133                         die("Could not write to %s", git_path("MERGE_MSG"));
1134                 close(fd);
1135         }
1137         if (merge_was_ok) {
1138                 fprintf(stderr, "Automatic merge went well; "
1139                         "stopped before committing as requested\n");
1140                 return 0;
1141         } else
1142                 return suggest_conflicts();