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