git.oblomov.eu Git - git/blob - merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "tree-walk.h"
  11 #include "diff.h"
  12 #include "diffcore.h"
  13 #include "run-command.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "path-list.h"
  17 #include "xdiff-interface.h"
  18
  19 static int subtree_merge;
  20
  21 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  22 {
  23         unsigned char shifted[20];
  24
  25         /*
  26          * NEEDSWORK: this limits the recursion depth to hardcoded
  27          * value '2' to avoid excessive overhead.
  28          */
  29         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  30         if (!hashcmp(two->object.sha1, shifted))
  31                 return two;
  32         return lookup_tree(shifted);
  33 }
  34
  35 /*
  36  * A virtual commit has
  37  * - (const char *)commit->util set to the name, and
  38  * - *(int *)commit->object.sha1 set to the virtual id.
  39  */
  40
  41 static unsigned commit_list_count(const struct commit_list *l)
  42 {
  43         unsigned c = 0;
  44         for (; l; l = l->next )
  45                 c++;
  46         return c;
  47 }
  48
  49 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  50 {
  51         struct commit *commit = xcalloc(1, sizeof(struct commit));
  52         static unsigned virtual_id = 1;
  53         commit->tree = tree;
  54         commit->util = (void*)comment;
  55         *(int*)commit->object.sha1 = virtual_id++;
  56         /* avoid warnings */
  57         commit->object.parsed = 1;
  58         return commit;
  59 }
  60
  61 /*
  62  * Since we use get_tree_entry(), which does not put the read object into
  63  * the object pool, we cannot rely on a == b.
  64  */
  65 static int sha_eq(const unsigned char *a, const unsigned char *b)
  66 {
  67         if (!a && !b)
  68                 return 2;
  69         return a && b && hashcmp(a, b) == 0;
  70 }
  71
  72 /*
  73  * Since we want to write the index eventually, we cannot reuse the index
  74  * for these (temporary) data.
  75  */
  76 struct stage_data
  77 {
  78         struct
  79         {
  80                 unsigned mode;
  81                 unsigned char sha[20];
  82         } stages[4];
  83         unsigned processed:1;
  84 };
  85
  86 struct output_buffer
  87 {
  88         struct output_buffer *next;
  89         char *str;
  90 };
  91
  92 static struct path_list current_file_set = {NULL, 0, 0, 1};
  93 static struct path_list current_directory_set = {NULL, 0, 0, 1};
  94
  95 static int call_depth = 0;
  96 static int verbosity = 2;
  97 static int buffer_output = 1;
  98 static struct output_buffer *output_list, *output_end;
  99
 100 static int show (int v)
 101 {
 102         return (!call_depth && verbosity >= v) || verbosity >= 5;
 103 }
 104
 105 static void output(int v, const char *fmt, ...)
 106 {
 107         va_list args;
 108         va_start(args, fmt);
 109         if (buffer_output && show(v)) {
 110                 struct output_buffer *b = xmalloc(sizeof(*b));
 111                 nfvasprintf(&b->str, fmt, args);
 112                 b->next = NULL;
 113                 if (output_end)
 114                         output_end->next = b;
 115                 else
 116                         output_list = b;
 117                 output_end = b;
 118         } else if (show(v)) {
 119                 int i;
 120                 for (i = call_depth; i--;)
 121                         fputs("  ", stdout);
 122                 vfprintf(stdout, fmt, args);
 123                 fputc('\n', stdout);
 124         }
 125         va_end(args);
 126 }
 127
 128 static void flush_output()
 129 {
 130         struct output_buffer *b, *n;
 131         for (b = output_list; b; b = n) {
 132                 int i;
 133                 for (i = call_depth; i--;)
 134                         fputs("  ", stdout);
 135                 fputs(b->str, stdout);
 136                 fputc('\n', stdout);
 137                 n = b->next;
 138                 free(b->str);
 139                 free(b);
 140         }
 141         output_list = NULL;
 142         output_end = NULL;
 143 }
 144
 145 static void output_commit_title(struct commit *commit)
 146 {
 147         int i;
 148         flush_output();
 149         for (i = call_depth; i--;)
 150                 fputs("  ", stdout);
 151         if (commit->util)
 152                 printf("virtual %s\n", (char *)commit->util);
 153         else {
 154                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 155                 if (parse_commit(commit) != 0)
 156                         printf("(bad commit)\n");
 157                 else {
 158                         const char *s;
 159                         int len;
 160                         for (s = commit->buffer; *s; s++)
 161                                 if (*s == '\n' && s[1] == '\n') {
 162                                         s += 2;
 163                                         break;
 164                                 }
 165                         for (len = 0; s[len] && '\n' != s[len]; len++)
 166                                 ; /* do nothing */
 167                         printf("%.*s\n", len, s);
 168                 }
 169         }
 170 }
 171
 172 static struct cache_entry *make_cache_entry(unsigned int mode,
 173                 const unsigned char *sha1, const char *path, int stage, int refresh)
 174 {
 175         int size, len;
 176         struct cache_entry *ce;
 177
 178         if (!verify_path(path))
 179                 return NULL;
 180
 181         len = strlen(path);
 182         size = cache_entry_size(len);
 183         ce = xcalloc(1, size);
 184
 185         hashcpy(ce->sha1, sha1);
 186         memcpy(ce->name, path, len);
 187         ce->ce_flags = create_ce_flags(len, stage);
 188         ce->ce_mode = create_ce_mode(mode);
 189
 190         if (refresh)
 191                 return refresh_cache_entry(ce, 0);
 192
 193         return ce;
 194 }
 195
 196 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 197                 const char *path, int stage, int refresh, int options)
 198 {
 199         struct cache_entry *ce;
 200         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 201         if (!ce)
 202                 return error("addinfo_cache failed for path '%s'", path);
 203         return add_cache_entry(ce, options);
 204 }
 205
 206 /*
 207  * This is a global variable which is used in a number of places but
 208  * only written to in the 'merge' function.
 209  *
 210  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 211  *                       don't update the working directory.
 212  *               0    => Leave unmerged entries in the cache and update
 213  *                       the working directory.
 214  */
 215 static int index_only = 0;
 216
 217 static int git_merge_trees(int index_only,
 218                            struct tree *common,
 219                            struct tree *head,
 220                            struct tree *merge)
 221 {
 222         int rc;
 223         struct object_list *trees = NULL;
 224         struct unpack_trees_options opts;
 225
 226         memset(&opts, 0, sizeof(opts));
 227         if (index_only)
 228                 opts.index_only = 1;
 229         else
 230                 opts.update = 1;
 231         opts.merge = 1;
 232         opts.head_idx = 2;
 233         opts.fn = threeway_merge;
 234
 235         object_list_append(&common->object, &trees);
 236         object_list_append(&head->object, &trees);
 237         object_list_append(&merge->object, &trees);
 238
 239         rc = unpack_trees(trees, &opts);
 240         cache_tree_free(&active_cache_tree);
 241         return rc;
 242 }
 243
 244 static int unmerged_index(void)
 245 {
 246         int i;
 247         for (i = 0; i < active_nr; i++) {
 248                 struct cache_entry *ce = active_cache[i];
 249                 if (ce_stage(ce))
 250                         return 1;
 251         }
 252         return 0;
 253 }
 254
 255 static struct tree *git_write_tree(void)
 256 {
 257         struct tree *result = NULL;
 258
 259         if (unmerged_index()) {
 260                 int i;
 261                 output(0, "There are unmerged index entries:");
 262                 for (i = 0; i < active_nr; i++) {
 263                         struct cache_entry *ce = active_cache[i];
 264                         if (ce_stage(ce))
 265                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 266                 }
 267                 return NULL;
 268         }
 269
 270         if (!active_cache_tree)
 271                 active_cache_tree = cache_tree();
 272
 273         if (!cache_tree_fully_valid(active_cache_tree) &&
 274             cache_tree_update(active_cache_tree,
 275                               active_cache, active_nr, 0, 0) < 0)
 276                 die("error building trees");
 277
 278         result = lookup_tree(active_cache_tree->sha1);
 279
 280         return result;
 281 }
 282
 283 static int save_files_dirs(const unsigned char *sha1,
 284                 const char *base, int baselen, const char *path,
 285                 unsigned int mode, int stage)
 286 {
 287         int len = strlen(path);
 288         char *newpath = xmalloc(baselen + len + 1);
 289         memcpy(newpath, base, baselen);
 290         memcpy(newpath + baselen, path, len);
 291         newpath[baselen + len] = '\0';
 292
 293         if (S_ISDIR(mode))
 294                 path_list_insert(newpath, &current_directory_set);
 295         else
 296                 path_list_insert(newpath, &current_file_set);
 297         free(newpath);
 298
 299         return READ_TREE_RECURSIVE;
 300 }
 301
 302 static int get_files_dirs(struct tree *tree)
 303 {
 304         int n;
 305         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 306                 return 0;
 307         n = current_file_set.nr + current_directory_set.nr;
 308         return n;
 309 }
 310
 311 /*
 312  * Returns a index_entry instance which doesn't have to correspond to
 313  * a real cache entry in Git's index.
 314  */
 315 static struct stage_data *insert_stage_data(const char *path,
 316                 struct tree *o, struct tree *a, struct tree *b,
 317                 struct path_list *entries)
 318 {
 319         struct path_list_item *item;
 320         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 321         get_tree_entry(o->object.sha1, path,
 322                         e->stages[1].sha, &e->stages[1].mode);
 323         get_tree_entry(a->object.sha1, path,
 324                         e->stages[2].sha, &e->stages[2].mode);
 325         get_tree_entry(b->object.sha1, path,
 326                         e->stages[3].sha, &e->stages[3].mode);
 327         item = path_list_insert(path, entries);
 328         item->util = e;
 329         return e;
 330 }
 331
 332 /*
 333  * Create a dictionary mapping file names to stage_data objects. The
 334  * dictionary contains one entry for every path with a non-zero stage entry.
 335  */
 336 static struct path_list *get_unmerged(void)
 337 {
 338         struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 339         int i;
 340
 341         unmerged->strdup_paths = 1;
 342
 343         for (i = 0; i < active_nr; i++) {
 344                 struct path_list_item *item;
 345                 struct stage_data *e;
 346                 struct cache_entry *ce = active_cache[i];
 347                 if (!ce_stage(ce))
 348                         continue;
 349
 350                 item = path_list_lookup(ce->name, unmerged);
 351                 if (!item) {
 352                         item = path_list_insert(ce->name, unmerged);
 353                         item->util = xcalloc(1, sizeof(struct stage_data));
 354                 }
 355                 e = item->util;
 356                 e->stages[ce_stage(ce)].mode = ntohl(ce->ce_mode);
 357                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 358         }
 359
 360         return unmerged;
 361 }
 362
 363 struct rename
 364 {
 365         struct diff_filepair *pair;
 366         struct stage_data *src_entry;
 367         struct stage_data *dst_entry;
 368         unsigned processed:1;
 369 };
 370
 371 /*
 372  * Get information of all renames which occurred between 'o_tree' and
 373  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 374  * 'b_tree') to be able to associate the correct cache entries with
 375  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 376  */
 377 static struct path_list *get_renames(struct tree *tree,
 378                                         struct tree *o_tree,
 379                                         struct tree *a_tree,
 380                                         struct tree *b_tree,
 381                                         struct path_list *entries)
 382 {
 383         int i;
 384         struct path_list *renames;
 385         struct diff_options opts;
 386
 387         renames = xcalloc(1, sizeof(struct path_list));
 388         diff_setup(&opts);
 389         opts.recursive = 1;
 390         opts.detect_rename = DIFF_DETECT_RENAME;
 391         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 392         if (diff_setup_done(&opts) < 0)
 393                 die("diff setup failed");
 394         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 395         diffcore_std(&opts);
 396         for (i = 0; i < diff_queued_diff.nr; ++i) {
 397                 struct path_list_item *item;
 398                 struct rename *re;
 399                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 400                 if (pair->status != 'R') {
 401                         diff_free_filepair(pair);
 402                         continue;
 403                 }
 404                 re = xmalloc(sizeof(*re));
 405                 re->processed = 0;
 406                 re->pair = pair;
 407                 item = path_list_lookup(re->pair->one->path, entries);
 408                 if (!item)
 409                         re->src_entry = insert_stage_data(re->pair->one->path,
 410                                         o_tree, a_tree, b_tree, entries);
 411                 else
 412                         re->src_entry = item->util;
 413
 414                 item = path_list_lookup(re->pair->two->path, entries);
 415                 if (!item)
 416                         re->dst_entry = insert_stage_data(re->pair->two->path,
 417                                         o_tree, a_tree, b_tree, entries);
 418                 else
 419                         re->dst_entry = item->util;
 420                 item = path_list_insert(pair->one->path, renames);
 421                 item->util = re;
 422         }
 423         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 424         diff_queued_diff.nr = 0;
 425         diff_flush(&opts);
 426         return renames;
 427 }
 428
 429 static int update_stages(const char *path, struct diff_filespec *o,
 430                          struct diff_filespec *a, struct diff_filespec *b,
 431                          int clear)
 432 {
 433         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 434         if (clear)
 435                 if (remove_file_from_cache(path))
 436                         return -1;
 437         if (o)
 438                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 439                         return -1;
 440         if (a)
 441                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 442                         return -1;
 443         if (b)
 444                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 445                         return -1;
 446         return 0;
 447 }
 448
 449 static int remove_path(const char *name)
 450 {
 451         int ret, len;
 452         char *slash, *dirs;
 453
 454         ret = unlink(name);
 455         if (ret)
 456                 return ret;
 457         len = strlen(name);
 458         dirs = xmalloc(len+1);
 459         memcpy(dirs, name, len);
 460         dirs[len] = '\0';
 461         while ((slash = strrchr(name, '/'))) {
 462                 *slash = '\0';
 463                 len = slash - name;
 464                 if (rmdir(name) != 0)
 465                         break;
 466         }
 467         free(dirs);
 468         return ret;
 469 }
 470
 471 static int remove_file(int clean, const char *path, int no_wd)
 472 {
 473         int update_cache = index_only || clean;
 474         int update_working_directory = !index_only && !no_wd;
 475
 476         if (update_cache) {
 477                 if (remove_file_from_cache(path))
 478                         return -1;
 479         }
 480         if (update_working_directory) {
 481                 unlink(path);
 482                 if (errno != ENOENT || errno != EISDIR)
 483                         return -1;
 484                 remove_path(path);
 485         }
 486         return 0;
 487 }
 488
 489 static char *unique_path(const char *path, const char *branch)
 490 {
 491         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 492         int suffix = 0;
 493         struct stat st;
 494         char *p = newpath + strlen(path);
 495         strcpy(newpath, path);
 496         *(p++) = '~';
 497         strcpy(p, branch);
 498         for (; *p; ++p)
 499                 if ('/' == *p)
 500                         *p = '_';
 501         while (path_list_has_path(&current_file_set, newpath) ||
 502                path_list_has_path(&current_directory_set, newpath) ||
 503                lstat(newpath, &st) == 0)
 504                 sprintf(p, "_%d", suffix++);
 505
 506         path_list_insert(newpath, &current_file_set);
 507         return newpath;
 508 }
 509
 510 static int mkdir_p(const char *path, unsigned long mode)
 511 {
 512         /* path points to cache entries, so xstrdup before messing with it */
 513         char *buf = xstrdup(path);
 514         int result = safe_create_leading_directories(buf);
 515         free(buf);
 516         return result;
 517 }
 518
 519 static void flush_buffer(int fd, const char *buf, unsigned long size)
 520 {
 521         while (size > 0) {
 522                 long ret = write_in_full(fd, buf, size);
 523                 if (ret < 0) {
 524                         /* Ignore epipe */
 525                         if (errno == EPIPE)
 526                                 break;
 527                         die("merge-recursive: %s", strerror(errno));
 528                 } else if (!ret) {
 529                         die("merge-recursive: disk full?");
 530                 }
 531                 size -= ret;
 532                 buf += ret;
 533         }
 534 }
 535
 536 static int make_room_for_path(const char *path)
 537 {
 538         int status;
 539         const char *msg = "failed to create path '%s'%s";
 540
 541         status = mkdir_p(path, 0777);
 542         if (status) {
 543                 if (status == -3) {
 544                         /* something else exists */
 545                         error(msg, path, ": perhaps a D/F conflict?");
 546                         return -1;
 547                 }
 548                 die(msg, path, "");
 549         }
 550
 551         /* Successful unlink is good.. */
 552         if (!unlink(path))
 553                 return 0;
 554         /* .. and so is no existing file */
 555         if (errno == ENOENT)
 556                 return 0;
 557         /* .. but not some other error (who really cares what?) */
 558         return error(msg, path, ": perhaps a D/F conflict?");
 559 }
 560
 561 static void update_file_flags(const unsigned char *sha,
 562                               unsigned mode,
 563                               const char *path,
 564                               int update_cache,
 565                               int update_wd)
 566 {
 567         if (index_only)
 568                 update_wd = 0;
 569
 570         if (update_wd) {
 571                 enum object_type type;
 572                 void *buf;
 573                 unsigned long size;
 574
 575                 buf = read_sha1_file(sha, &type, &size);
 576                 if (!buf)
 577                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 578                 if (type != OBJ_BLOB)
 579                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 580
 581                 if (make_room_for_path(path) < 0) {
 582                         update_wd = 0;
 583                         goto update_index;
 584                 }
 585                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 586                         int fd;
 587                         if (mode & 0100)
 588                                 mode = 0777;
 589                         else
 590                                 mode = 0666;
 591                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 592                         if (fd < 0)
 593                                 die("failed to open %s: %s", path, strerror(errno));
 594                         flush_buffer(fd, buf, size);
 595                         close(fd);
 596                 } else if (S_ISLNK(mode)) {
 597                         char *lnk = xmalloc(size + 1);
 598                         memcpy(lnk, buf, size);
 599                         lnk[size] = '\0';
 600                         mkdir_p(path, 0777);
 601                         unlink(path);
 602                         symlink(lnk, path);
 603                         free(lnk);
 604                 } else
 605                         die("do not know what to do with %06o %s '%s'",
 606                             mode, sha1_to_hex(sha), path);
 607         }
 608  update_index:
 609         if (update_cache)
 610                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 611 }
 612
 613 static void update_file(int clean,
 614                         const unsigned char *sha,
 615                         unsigned mode,
 616                         const char *path)
 617 {
 618         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 619 }
 620
 621 /* Low level file merging, update and removal */
 622
 623 struct merge_file_info
 624 {
 625         unsigned char sha[20];
 626         unsigned mode;
 627         unsigned clean:1,
 628                  merge:1;
 629 };
 630
 631 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 632 {
 633         unsigned long size;
 634         enum object_type type;
 635
 636         if (!hashcmp(sha1, null_sha1)) {
 637                 mm->ptr = xstrdup("");
 638                 mm->size = 0;
 639                 return;
 640         }
 641
 642         mm->ptr = read_sha1_file(sha1, &type, &size);
 643         if (!mm->ptr || type != OBJ_BLOB)
 644                 die("unable to read blob object %s", sha1_to_hex(sha1));
 645         mm->size = size;
 646 }
 647
 648 static struct merge_file_info merge_file(struct diff_filespec *o,
 649                 struct diff_filespec *a, struct diff_filespec *b,
 650                 const char *branch1, const char *branch2)
 651 {
 652         struct merge_file_info result;
 653         result.merge = 0;
 654         result.clean = 1;
 655
 656         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 657                 result.clean = 0;
 658                 if (S_ISREG(a->mode)) {
 659                         result.mode = a->mode;
 660                         hashcpy(result.sha, a->sha1);
 661                 } else {
 662                         result.mode = b->mode;
 663                         hashcpy(result.sha, b->sha1);
 664                 }
 665         } else {
 666                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 667                         result.merge = 1;
 668
 669                 result.mode = a->mode == o->mode ? b->mode: a->mode;
 670
 671                 if (sha_eq(a->sha1, o->sha1))
 672                         hashcpy(result.sha, b->sha1);
 673                 else if (sha_eq(b->sha1, o->sha1))
 674                         hashcpy(result.sha, a->sha1);
 675                 else if (S_ISREG(a->mode)) {
 676                         mmfile_t orig, src1, src2;
 677                         mmbuffer_t result_buf;
 678                         xpparam_t xpp;
 679                         char *name1, *name2;
 680                         int merge_status;
 681
 682                         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 683                         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 684
 685                         fill_mm(o->sha1, &orig);
 686                         fill_mm(a->sha1, &src1);
 687                         fill_mm(b->sha1, &src2);
 688
 689                         memset(&xpp, 0, sizeof(xpp));
 690                         merge_status = xdl_merge(&orig,
 691                                                  &src1, name1,
 692                                                  &src2, name2,
 693                                                  &xpp, XDL_MERGE_ZEALOUS,
 694                                                  &result_buf);
 695                         free(name1);
 696                         free(name2);
 697                         free(orig.ptr);
 698                         free(src1.ptr);
 699                         free(src2.ptr);
 700
 701                         if ((merge_status < 0) || !result_buf.ptr)
 702                                 die("Failed to execute internal merge");
 703
 704                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 705                                             blob_type, result.sha))
 706                                 die("Unable to add %s to database",
 707                                     a->path);
 708
 709                         free(result_buf.ptr);
 710                         result.clean = (merge_status == 0);
 711                 } else {
 712                         if (!(S_ISLNK(a->mode) || S_ISLNK(b->mode)))
 713                                 die("cannot merge modes?");
 714
 715                         hashcpy(result.sha, a->sha1);
 716
 717                         if (!sha_eq(a->sha1, b->sha1))
 718                                 result.clean = 0;
 719                 }
 720         }
 721
 722         return result;
 723 }
 724
 725 static void conflict_rename_rename(struct rename *ren1,
 726                                    const char *branch1,
 727                                    struct rename *ren2,
 728                                    const char *branch2)
 729 {
 730         char *del[2];
 731         int delp = 0;
 732         const char *ren1_dst = ren1->pair->two->path;
 733         const char *ren2_dst = ren2->pair->two->path;
 734         const char *dst_name1 = ren1_dst;
 735         const char *dst_name2 = ren2_dst;
 736         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 737                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 738                 output(1, "%s is a directory in %s added as %s instead",
 739                        ren1_dst, branch2, dst_name1);
 740                 remove_file(0, ren1_dst, 0);
 741         }
 742         if (path_list_has_path(&current_directory_set, ren2_dst)) {
 743                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 744                 output(1, "%s is a directory in %s added as %s instead",
 745                        ren2_dst, branch1, dst_name2);
 746                 remove_file(0, ren2_dst, 0);
 747         }
 748         if (index_only) {
 749                 remove_file_from_cache(dst_name1);
 750                 remove_file_from_cache(dst_name2);
 751                 /*
 752                  * Uncomment to leave the conflicting names in the resulting tree
 753                  *
 754                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 755                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 756                  */
 757         } else {
 758                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 759                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 760         }
 761         while (delp--)
 762                 free(del[delp]);
 763 }
 764
 765 static void conflict_rename_dir(struct rename *ren1,
 766                                 const char *branch1)
 767 {
 768         char *new_path = unique_path(ren1->pair->two->path, branch1);
 769         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
 770         remove_file(0, ren1->pair->two->path, 0);
 771         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 772         free(new_path);
 773 }
 774
 775 static void conflict_rename_rename_2(struct rename *ren1,
 776                                      const char *branch1,
 777                                      struct rename *ren2,
 778                                      const char *branch2)
 779 {
 780         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 781         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 782         output(1, "Renamed %s to %s and %s to %s instead",
 783                ren1->pair->one->path, new_path1,
 784                ren2->pair->one->path, new_path2);
 785         remove_file(0, ren1->pair->two->path, 0);
 786         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 787         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 788         free(new_path2);
 789         free(new_path1);
 790 }
 791
 792 static int process_renames(struct path_list *a_renames,
 793                            struct path_list *b_renames,
 794                            const char *a_branch,
 795                            const char *b_branch)
 796 {
 797         int clean_merge = 1, i, j;
 798         struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 799         const struct rename *sre;
 800
 801         for (i = 0; i < a_renames->nr; i++) {
 802                 sre = a_renames->items[i].util;
 803                 path_list_insert(sre->pair->two->path, &a_by_dst)->util
 804                         = sre->dst_entry;
 805         }
 806         for (i = 0; i < b_renames->nr; i++) {
 807                 sre = b_renames->items[i].util;
 808                 path_list_insert(sre->pair->two->path, &b_by_dst)->util
 809                         = sre->dst_entry;
 810         }
 811
 812         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 813                 int compare;
 814                 char *src;
 815                 struct path_list *renames1, *renames2, *renames2Dst;
 816                 struct rename *ren1 = NULL, *ren2 = NULL;
 817                 const char *branch1, *branch2;
 818                 const char *ren1_src, *ren1_dst;
 819
 820                 if (i >= a_renames->nr) {
 821                         compare = 1;
 822                         ren2 = b_renames->items[j++].util;
 823                 } else if (j >= b_renames->nr) {
 824                         compare = -1;
 825                         ren1 = a_renames->items[i++].util;
 826                 } else {
 827                         compare = strcmp(a_renames->items[i].path,
 828                                         b_renames->items[j].path);
 829                         if (compare <= 0)
 830                                 ren1 = a_renames->items[i++].util;
 831                         if (compare >= 0)
 832                                 ren2 = b_renames->items[j++].util;
 833                 }
 834
 835                 /* TODO: refactor, so that 1/2 are not needed */
 836                 if (ren1) {
 837                         renames1 = a_renames;
 838                         renames2 = b_renames;
 839                         renames2Dst = &b_by_dst;
 840                         branch1 = a_branch;
 841                         branch2 = b_branch;
 842                 } else {
 843                         struct rename *tmp;
 844                         renames1 = b_renames;
 845                         renames2 = a_renames;
 846                         renames2Dst = &a_by_dst;
 847                         branch1 = b_branch;
 848                         branch2 = a_branch;
 849                         tmp = ren2;
 850                         ren2 = ren1;
 851                         ren1 = tmp;
 852                 }
 853                 src = ren1->pair->one->path;
 854
 855                 ren1->dst_entry->processed = 1;
 856                 ren1->src_entry->processed = 1;
 857
 858                 if (ren1->processed)
 859                         continue;
 860                 ren1->processed = 1;
 861
 862                 ren1_src = ren1->pair->one->path;
 863                 ren1_dst = ren1->pair->two->path;
 864
 865                 if (ren2) {
 866                         const char *ren2_src = ren2->pair->one->path;
 867                         const char *ren2_dst = ren2->pair->two->path;
 868                         /* Renamed in 1 and renamed in 2 */
 869                         if (strcmp(ren1_src, ren2_src) != 0)
 870                                 die("ren1.src != ren2.src");
 871                         ren2->dst_entry->processed = 1;
 872                         ren2->processed = 1;
 873                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 874                                 clean_merge = 0;
 875                                 output(1, "CONFLICT (rename/rename): "
 876                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 877                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 878                                        src, ren1_dst, branch1,
 879                                        src, ren2_dst, branch2,
 880                                        index_only ? " (left unresolved)": "");
 881                                 if (index_only) {
 882                                         remove_file_from_cache(src);
 883                                         update_file(0, ren1->pair->one->sha1,
 884                                                     ren1->pair->one->mode, src);
 885                                 }
 886                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 887                         } else {
 888                                 struct merge_file_info mfi;
 889                                 remove_file(1, ren1_src, 1);
 890                                 mfi = merge_file(ren1->pair->one,
 891                                                  ren1->pair->two,
 892                                                  ren2->pair->two,
 893                                                  branch1,
 894                                                  branch2);
 895                                 if (mfi.merge || !mfi.clean)
 896                                         output(1, "Renamed %s->%s", src, ren1_dst);
 897
 898                                 if (mfi.merge)
 899                                         output(2, "Auto-merged %s", ren1_dst);
 900
 901                                 if (!mfi.clean) {
 902                                         output(1, "CONFLICT (content): merge conflict in %s",
 903                                                ren1_dst);
 904                                         clean_merge = 0;
 905
 906                                         if (!index_only)
 907                                                 update_stages(ren1_dst,
 908                                                               ren1->pair->one,
 909                                                               ren1->pair->two,
 910                                                               ren2->pair->two,
 911                                                               1 /* clear */);
 912                                 }
 913                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 914                         }
 915                 } else {
 916                         /* Renamed in 1, maybe changed in 2 */
 917                         struct path_list_item *item;
 918                         /* we only use sha1 and mode of these */
 919                         struct diff_filespec src_other, dst_other;
 920                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 921
 922                         remove_file(1, ren1_src, index_only || stage == 3);
 923
 924                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 925                         src_other.mode = ren1->src_entry->stages[stage].mode;
 926                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 927                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 928
 929                         try_merge = 0;
 930
 931                         if (path_list_has_path(&current_directory_set, ren1_dst)) {
 932                                 clean_merge = 0;
 933                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
 934                                        " directory %s added in %s",
 935                                        ren1_src, ren1_dst, branch1,
 936                                        ren1_dst, branch2);
 937                                 conflict_rename_dir(ren1, branch1);
 938                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 939                                 clean_merge = 0;
 940                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
 941                                        "and deleted in %s",
 942                                        ren1_src, ren1_dst, branch1,
 943                                        branch2);
 944                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 945                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 946                                 const char *new_path;
 947                                 clean_merge = 0;
 948                                 try_merge = 1;
 949                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
 950                                        "%s added in %s",
 951                                        ren1_src, ren1_dst, branch1,
 952                                        ren1_dst, branch2);
 953                                 new_path = unique_path(ren1_dst, branch2);
 954                                 output(1, "Added as %s instead", new_path);
 955                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 956                         } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 957                                 ren2 = item->util;
 958                                 clean_merge = 0;
 959                                 ren2->processed = 1;
 960                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
 961                                        "Renamed %s->%s in %s",
 962                                        ren1_src, ren1_dst, branch1,
 963                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 964                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 965                         } else
 966                                 try_merge = 1;
 967
 968                         if (try_merge) {
 969                                 struct diff_filespec *o, *a, *b;
 970                                 struct merge_file_info mfi;
 971                                 src_other.path = (char *)ren1_src;
 972
 973                                 o = ren1->pair->one;
 974                                 if (a_renames == renames1) {
 975                                         a = ren1->pair->two;
 976                                         b = &src_other;
 977                                 } else {
 978                                         b = ren1->pair->two;
 979                                         a = &src_other;
 980                                 }
 981                                 mfi = merge_file(o, a, b,
 982                                                 a_branch, b_branch);
 983
 984                                 if (mfi.merge || !mfi.clean)
 985                                         output(1, "Renamed %s => %s", ren1_src, ren1_dst);
 986                                 if (mfi.merge)
 987                                         output(2, "Auto-merged %s", ren1_dst);
 988                                 if (!mfi.clean) {
 989                                         output(1, "CONFLICT (rename/modify): Merge conflict in %s",
 990                                                ren1_dst);
 991                                         clean_merge = 0;
 992
 993                                         if (!index_only)
 994                                                 update_stages(ren1_dst,
 995                                                                 o, a, b, 1);
 996                                 }
 997                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 998                         }
 999                 }
1000         }
1001         path_list_clear(&a_by_dst, 0);
1002         path_list_clear(&b_by_dst, 0);
1003
1004         return clean_merge;
1005 }
1006
1007 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1008 {
1009         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1010 }
1011
1012 /* Per entry merge function */
1013 static int process_entry(const char *path, struct stage_data *entry,
1014                          const char *branch1,
1015                          const char *branch2)
1016 {
1017         /*
1018         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1019         print_index_entry("\tpath: ", entry);
1020         */
1021         int clean_merge = 1;
1022         unsigned o_mode = entry->stages[1].mode;
1023         unsigned a_mode = entry->stages[2].mode;
1024         unsigned b_mode = entry->stages[3].mode;
1025         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1026         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1027         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1028
1029         if (o_sha && (!a_sha || !b_sha)) {
1030                 /* Case A: Deleted in one */
1031                 if ((!a_sha && !b_sha) ||
1032                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1033                     (!a_sha && sha_eq(b_sha, o_sha))) {
1034                         /* Deleted in both or deleted in one and
1035                          * unchanged in the other */
1036                         if (a_sha)
1037                                 output(2, "Removed %s", path);
1038                         /* do not touch working file if it did not exist */
1039                         remove_file(1, path, !a_sha);
1040                 } else {
1041                         /* Deleted in one and changed in the other */
1042                         clean_merge = 0;
1043                         if (!a_sha) {
1044                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1045                                        "and modified in %s. Version %s of %s left in tree.",
1046                                        path, branch1,
1047                                        branch2, branch2, path);
1048                                 update_file(0, b_sha, b_mode, path);
1049                         } else {
1050                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1051                                        "and modified in %s. Version %s of %s left in tree.",
1052                                        path, branch2,
1053                                        branch1, branch1, path);
1054                                 update_file(0, a_sha, a_mode, path);
1055                         }
1056                 }
1057
1058         } else if ((!o_sha && a_sha && !b_sha) ||
1059                    (!o_sha && !a_sha && b_sha)) {
1060                 /* Case B: Added in one. */
1061                 const char *add_branch;
1062                 const char *other_branch;
1063                 unsigned mode;
1064                 const unsigned char *sha;
1065                 const char *conf;
1066
1067                 if (a_sha) {
1068                         add_branch = branch1;
1069                         other_branch = branch2;
1070                         mode = a_mode;
1071                         sha = a_sha;
1072                         conf = "file/directory";
1073                 } else {
1074                         add_branch = branch2;
1075                         other_branch = branch1;
1076                         mode = b_mode;
1077                         sha = b_sha;
1078                         conf = "directory/file";
1079                 }
1080                 if (path_list_has_path(&current_directory_set, path)) {
1081                         const char *new_path = unique_path(path, add_branch);
1082                         clean_merge = 0;
1083                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1084                                "Added %s as %s",
1085                                conf, path, other_branch, path, new_path);
1086                         remove_file(0, path, 0);
1087                         update_file(0, sha, mode, new_path);
1088                 } else {
1089                         output(2, "Added %s", path);
1090                         update_file(1, sha, mode, path);
1091                 }
1092         } else if (a_sha && b_sha) {
1093                 /* Case C: Added in both (check for same permissions) and */
1094                 /* case D: Modified in both, but differently. */
1095                 const char *reason = "content";
1096                 struct merge_file_info mfi;
1097                 struct diff_filespec o, a, b;
1098
1099                 if (!o_sha) {
1100                         reason = "add/add";
1101                         o_sha = (unsigned char *)null_sha1;
1102                 }
1103                 output(2, "Auto-merged %s", path);
1104                 o.path = a.path = b.path = (char *)path;
1105                 hashcpy(o.sha1, o_sha);
1106                 o.mode = o_mode;
1107                 hashcpy(a.sha1, a_sha);
1108                 a.mode = a_mode;
1109                 hashcpy(b.sha1, b_sha);
1110                 b.mode = b_mode;
1111
1112                 mfi = merge_file(&o, &a, &b,
1113                                  branch1, branch2);
1114
1115                 if (mfi.clean)
1116                         update_file(1, mfi.sha, mfi.mode, path);
1117                 else {
1118                         clean_merge = 0;
1119                         output(1, "CONFLICT (%s): Merge conflict in %s",
1120                                         reason, path);
1121
1122                         if (index_only)
1123                                 update_file(0, mfi.sha, mfi.mode, path);
1124                         else
1125                                 update_file_flags(mfi.sha, mfi.mode, path,
1126                                               0 /* update_cache */, 1 /* update_working_directory */);
1127                 }
1128         } else if (!o_sha && !a_sha && !b_sha) {
1129                 /*
1130                  * this entry was deleted altogether. a_mode == 0 means
1131                  * we had that path and want to actively remove it.
1132                  */
1133                 remove_file(1, path, !a_mode);
1134         } else
1135                 die("Fatal merge failure, shouldn't happen.");
1136
1137         return clean_merge;
1138 }
1139
1140 static int merge_trees(struct tree *head,
1141                        struct tree *merge,
1142                        struct tree *common,
1143                        const char *branch1,
1144                        const char *branch2,
1145                        struct tree **result)
1146 {
1147         int code, clean;
1148
1149         if (subtree_merge) {
1150                 merge = shift_tree_object(head, merge);
1151                 common = shift_tree_object(head, common);
1152         }
1153
1154         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1155                 output(0, "Already uptodate!");
1156                 *result = head;
1157                 return 1;
1158         }
1159
1160         code = git_merge_trees(index_only, common, head, merge);
1161
1162         if (code != 0)
1163                 die("merging of trees %s and %s failed",
1164                     sha1_to_hex(head->object.sha1),
1165                     sha1_to_hex(merge->object.sha1));
1166
1167         if (unmerged_index()) {
1168                 struct path_list *entries, *re_head, *re_merge;
1169                 int i;
1170                 path_list_clear(&current_file_set, 1);
1171                 path_list_clear(&current_directory_set, 1);
1172                 get_files_dirs(head);
1173                 get_files_dirs(merge);
1174
1175                 entries = get_unmerged();
1176                 re_head  = get_renames(head, common, head, merge, entries);
1177                 re_merge = get_renames(merge, common, head, merge, entries);
1178                 clean = process_renames(re_head, re_merge,
1179                                 branch1, branch2);
1180                 for (i = 0; i < entries->nr; i++) {
1181                         const char *path = entries->items[i].path;
1182                         struct stage_data *e = entries->items[i].util;
1183                         if (!e->processed
1184                                 && !process_entry(path, e, branch1, branch2))
1185                                 clean = 0;
1186                 }
1187
1188                 path_list_clear(re_merge, 0);
1189                 path_list_clear(re_head, 0);
1190                 path_list_clear(entries, 1);
1191
1192         }
1193         else
1194                 clean = 1;
1195
1196         if (index_only)
1197                 *result = git_write_tree();
1198
1199         return clean;
1200 }
1201
1202 static struct commit_list *reverse_commit_list(struct commit_list *list)
1203 {
1204         struct commit_list *next = NULL, *current, *backup;
1205         for (current = list; current; current = backup) {
1206                 backup = current->next;
1207                 current->next = next;
1208                 next = current;
1209         }
1210         return next;
1211 }
1212
1213 /*
1214  * Merge the commits h1 and h2, return the resulting virtual
1215  * commit object and a flag indicating the cleanness of the merge.
1216  */
1217 static int merge(struct commit *h1,
1218                  struct commit *h2,
1219                  const char *branch1,
1220                  const char *branch2,
1221                  struct commit_list *ca,
1222                  struct commit **result)
1223 {
1224         struct commit_list *iter;
1225         struct commit *merged_common_ancestors;
1226         struct tree *mrtree;
1227         int clean;
1228
1229         if (show(4)) {
1230                 output(4, "Merging:");
1231                 output_commit_title(h1);
1232                 output_commit_title(h2);
1233         }
1234
1235         if (!ca) {
1236                 ca = get_merge_bases(h1, h2, 1);
1237                 ca = reverse_commit_list(ca);
1238         }
1239
1240         if (show(5)) {
1241                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1242                 for (iter = ca; iter; iter = iter->next)
1243                         output_commit_title(iter->item);
1244         }
1245
1246         merged_common_ancestors = pop_commit(&ca);
1247         if (merged_common_ancestors == NULL) {
1248                 /* if there is no common ancestor, make an empty tree */
1249                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1250
1251                 tree->object.parsed = 1;
1252                 tree->object.type = OBJ_TREE;
1253                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1254                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1255         }
1256
1257         for (iter = ca; iter; iter = iter->next) {
1258                 call_depth++;
1259                 /*
1260                  * When the merge fails, the result contains files
1261                  * with conflict markers. The cleanness flag is
1262                  * ignored, it was never actually used, as result of
1263                  * merge_trees has always overwritten it: the committed
1264                  * "conflicts" were already resolved.
1265                  */
1266                 discard_cache();
1267                 merge(merged_common_ancestors, iter->item,
1268                       "Temporary merge branch 1",
1269                       "Temporary merge branch 2",
1270                       NULL,
1271                       &merged_common_ancestors);
1272                 call_depth--;
1273
1274                 if (!merged_common_ancestors)
1275                         die("merge returned no commit");
1276         }
1277
1278         discard_cache();
1279         if (!call_depth) {
1280                 read_cache();
1281                 index_only = 0;
1282         } else
1283                 index_only = 1;
1284
1285         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1286                             branch1, branch2, &mrtree);
1287
1288         if (index_only) {
1289                 *result = make_virtual_commit(mrtree, "merged tree");
1290                 commit_list_insert(h1, &(*result)->parents);
1291                 commit_list_insert(h2, &(*result)->parents->next);
1292         }
1293         flush_output();
1294         return clean;
1295 }
1296
1297 static const char *better_branch_name(const char *branch)
1298 {
1299         static char githead_env[8 + 40 + 1];
1300         char *name;
1301
1302         if (strlen(branch) != 40)
1303                 return branch;
1304         sprintf(githead_env, "GITHEAD_%s", branch);
1305         name = getenv(githead_env);
1306         return name ? name : branch;
1307 }
1308
1309 static struct commit *get_ref(const char *ref)
1310 {
1311         unsigned char sha1[20];
1312         struct object *object;
1313
1314         if (get_sha1(ref, sha1))
1315                 die("Could not resolve ref '%s'", ref);
1316         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1317         if (object->type == OBJ_TREE)
1318                 return make_virtual_commit((struct tree*)object,
1319                         better_branch_name(ref));
1320         if (object->type != OBJ_COMMIT)
1321                 return NULL;
1322         if (parse_commit((struct commit *)object))
1323                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1324         return (struct commit *)object;
1325 }
1326
1327 static int merge_config(const char *var, const char *value)
1328 {
1329         if (!strcasecmp(var, "merge.verbosity")) {
1330                 verbosity = git_config_int(var, value);
1331                 return 0;
1332         }
1333         return git_default_config(var, value);
1334 }
1335
1336 int main(int argc, char *argv[])
1337 {
1338         static const char *bases[20];
1339         static unsigned bases_count = 0;
1340         int i, clean;
1341         const char *branch1, *branch2;
1342         struct commit *result, *h1, *h2;
1343         struct commit_list *ca = NULL;
1344         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1345         int index_fd;
1346
1347         if (argv[0]) {
1348                 int namelen = strlen(argv[0]);
1349                 if (8 < namelen &&
1350                     !strcmp(argv[0] + namelen - 8, "-subtree"))
1351                         subtree_merge = 1;
1352         }
1353
1354         git_config(merge_config);
1355         if (getenv("GIT_MERGE_VERBOSITY"))
1356                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1357
1358         if (argc < 4)
1359                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1360
1361         for (i = 1; i < argc; ++i) {
1362                 if (!strcmp(argv[i], "--"))
1363                         break;
1364                 if (bases_count < sizeof(bases)/sizeof(*bases))
1365                         bases[bases_count++] = argv[i];
1366         }
1367         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1368                 die("Not handling anything other than two heads merge.");
1369         if (verbosity >= 5)
1370                 buffer_output = 0;
1371
1372         branch1 = argv[++i];
1373         branch2 = argv[++i];
1374
1375         h1 = get_ref(branch1);
1376         h2 = get_ref(branch2);
1377
1378         branch1 = better_branch_name(branch1);
1379         branch2 = better_branch_name(branch2);
1380
1381         if (show(3))
1382                 printf("Merging %s with %s\n", branch1, branch2);
1383
1384         index_fd = hold_locked_index(lock, 1);
1385
1386         for (i = 0; i < bases_count; i++) {
1387                 struct commit *ancestor = get_ref(bases[i]);
1388                 ca = commit_list_insert(ancestor, &ca);
1389         }
1390         clean = merge(h1, h2, branch1, branch2, ca, &result);
1391
1392         if (active_cache_changed &&
1393             (write_cache(index_fd, active_cache, active_nr) ||
1394              close(index_fd) || commit_locked_index(lock)))
1395                         die ("unable to write %s", get_index_file());
1396
1397         return clean ? 0: 1;
1398 }