git.oblomov.eu Git - git/blob - builtin-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 "builtin.h"
  11 #include "tree-walk.h"
  12 #include "diff.h"
  13 #include "diffcore.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "string-list.h"
  17 #include "xdiff-interface.h"
  18 #include "ll-merge.h"
  19 #include "interpolate.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22
  23 static int subtree_merge;
  24
  25 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  26 {
  27         unsigned char shifted[20];
  28
  29         /*
  30          * NEEDSWORK: this limits the recursion depth to hardcoded
  31          * value '2' to avoid excessive overhead.
  32          */
  33         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  34         if (!hashcmp(two->object.sha1, shifted))
  35                 return two;
  36         return lookup_tree(shifted);
  37 }
  38
  39 /*
  40  * A virtual commit has
  41  * - (const char *)commit->util set to the name, and
  42  * - *(int *)commit->object.sha1 set to the virtual id.
  43  */
  44
  45 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  46 {
  47         struct commit *commit = xcalloc(1, sizeof(struct commit));
  48         static unsigned virtual_id = 1;
  49         commit->tree = tree;
  50         commit->util = (void*)comment;
  51         *(int*)commit->object.sha1 = virtual_id++;
  52         /* avoid warnings */
  53         commit->object.parsed = 1;
  54         return commit;
  55 }
  56
  57 /*
  58  * Since we use get_tree_entry(), which does not put the read object into
  59  * the object pool, we cannot rely on a == b.
  60  */
  61 static int sha_eq(const unsigned char *a, const unsigned char *b)
  62 {
  63         if (!a && !b)
  64                 return 2;
  65         return a && b && hashcmp(a, b) == 0;
  66 }
  67
  68 /*
  69  * Since we want to write the index eventually, we cannot reuse the index
  70  * for these (temporary) data.
  71  */
  72 struct stage_data
  73 {
  74         struct
  75         {
  76                 unsigned mode;
  77                 unsigned char sha[20];
  78         } stages[4];
  79         unsigned processed:1;
  80 };
  81
  82 static struct string_list current_file_set = {NULL, 0, 0, 1};
  83 static struct string_list current_directory_set = {NULL, 0, 0, 1};
  84
  85 static int call_depth = 0;
  86 static int verbosity = 2;
  87 static int diff_rename_limit = -1;
  88 static int merge_rename_limit = -1;
  89 static int buffer_output = 1;
  90 static struct strbuf obuf = STRBUF_INIT;
  91
  92 static int show(int v)
  93 {
  94         return (!call_depth && verbosity >= v) || verbosity >= 5;
  95 }
  96
  97 static void flush_output(void)
  98 {
  99         if (obuf.len) {
 100                 fputs(obuf.buf, stdout);
 101                 strbuf_reset(&obuf);
 102         }
 103 }
 104
 105 static void output(int v, const char *fmt, ...)
 106 {
 107         int len;
 108         va_list ap;
 109
 110         if (!show(v))
 111                 return;
 112
 113         strbuf_grow(&obuf, call_depth * 2 + 2);
 114         memset(obuf.buf + obuf.len, ' ', call_depth * 2);
 115         strbuf_setlen(&obuf, obuf.len + call_depth * 2);
 116
 117         va_start(ap, fmt);
 118         len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 119         va_end(ap);
 120
 121         if (len < 0)
 122                 len = 0;
 123         if (len >= strbuf_avail(&obuf)) {
 124                 strbuf_grow(&obuf, len + 2);
 125                 va_start(ap, fmt);
 126                 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 127                 va_end(ap);
 128                 if (len >= strbuf_avail(&obuf)) {
 129                         die("this should not happen, your snprintf is broken");
 130                 }
 131         }
 132         strbuf_setlen(&obuf, obuf.len + len);
 133         strbuf_add(&obuf, "\n", 1);
 134         if (!buffer_output)
 135                 flush_output();
 136 }
 137
 138 static void output_commit_title(struct commit *commit)
 139 {
 140         int i;
 141         flush_output();
 142         for (i = call_depth; i--;)
 143                 fputs("  ", stdout);
 144         if (commit->util)
 145                 printf("virtual %s\n", (char *)commit->util);
 146         else {
 147                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 148                 if (parse_commit(commit) != 0)
 149                         printf("(bad commit)\n");
 150                 else {
 151                         const char *s;
 152                         int len;
 153                         for (s = commit->buffer; *s; s++)
 154                                 if (*s == '\n' && s[1] == '\n') {
 155                                         s += 2;
 156                                         break;
 157                                 }
 158                         for (len = 0; s[len] && '\n' != s[len]; len++)
 159                                 ; /* do nothing */
 160                         printf("%.*s\n", len, s);
 161                 }
 162         }
 163 }
 164
 165 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 166                 const char *path, int stage, int refresh, int options)
 167 {
 168         struct cache_entry *ce;
 169         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 170         if (!ce)
 171                 return error("addinfo_cache failed for path '%s'", path);
 172         return add_cache_entry(ce, options);
 173 }
 174
 175 /*
 176  * This is a global variable which is used in a number of places but
 177  * only written to in the 'merge' function.
 178  *
 179  * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 180  *                       don't update the working directory.
 181  *               0    => Leave unmerged entries in the cache and update
 182  *                       the working directory.
 183  */
 184 static int index_only = 0;
 185
 186 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 187 {
 188         parse_tree(tree);
 189         init_tree_desc(desc, tree->buffer, tree->size);
 190 }
 191
 192 static int git_merge_trees(int index_only,
 193                            struct tree *common,
 194                            struct tree *head,
 195                            struct tree *merge)
 196 {
 197         int rc;
 198         struct tree_desc t[3];
 199         struct unpack_trees_options opts;
 200
 201         memset(&opts, 0, sizeof(opts));
 202         if (index_only)
 203                 opts.index_only = 1;
 204         else
 205                 opts.update = 1;
 206         opts.merge = 1;
 207         opts.head_idx = 2;
 208         opts.fn = threeway_merge;
 209         opts.src_index = &the_index;
 210         opts.dst_index = &the_index;
 211
 212         init_tree_desc_from_tree(t+0, common);
 213         init_tree_desc_from_tree(t+1, head);
 214         init_tree_desc_from_tree(t+2, merge);
 215
 216         rc = unpack_trees(3, t, &opts);
 217         cache_tree_free(&active_cache_tree);
 218         return rc;
 219 }
 220
 221 struct tree *write_tree_from_memory(void)
 222 {
 223         struct tree *result = NULL;
 224
 225         if (unmerged_cache()) {
 226                 int i;
 227                 output(0, "There are unmerged index entries:");
 228                 for (i = 0; i < active_nr; i++) {
 229                         struct cache_entry *ce = active_cache[i];
 230                         if (ce_stage(ce))
 231                                 output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 232                 }
 233                 return NULL;
 234         }
 235
 236         if (!active_cache_tree)
 237                 active_cache_tree = cache_tree();
 238
 239         if (!cache_tree_fully_valid(active_cache_tree) &&
 240             cache_tree_update(active_cache_tree,
 241                               active_cache, active_nr, 0, 0) < 0)
 242                 die("error building trees");
 243
 244         result = lookup_tree(active_cache_tree->sha1);
 245
 246         return result;
 247 }
 248
 249 static int save_files_dirs(const unsigned char *sha1,
 250                 const char *base, int baselen, const char *path,
 251                 unsigned int mode, int stage, void *context)
 252 {
 253         int len = strlen(path);
 254         char *newpath = xmalloc(baselen + len + 1);
 255         memcpy(newpath, base, baselen);
 256         memcpy(newpath + baselen, path, len);
 257         newpath[baselen + len] = '\0';
 258
 259         if (S_ISDIR(mode))
 260                 string_list_insert(newpath, &current_directory_set);
 261         else
 262                 string_list_insert(newpath, &current_file_set);
 263         free(newpath);
 264
 265         return READ_TREE_RECURSIVE;
 266 }
 267
 268 static int get_files_dirs(struct tree *tree)
 269 {
 270         int n;
 271         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, NULL))
 272                 return 0;
 273         n = current_file_set.nr + current_directory_set.nr;
 274         return n;
 275 }
 276
 277 /*
 278  * Returns an index_entry instance which doesn't have to correspond to
 279  * a real cache entry in Git's index.
 280  */
 281 static struct stage_data *insert_stage_data(const char *path,
 282                 struct tree *o, struct tree *a, struct tree *b,
 283                 struct string_list *entries)
 284 {
 285         struct string_list_item *item;
 286         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 287         get_tree_entry(o->object.sha1, path,
 288                         e->stages[1].sha, &e->stages[1].mode);
 289         get_tree_entry(a->object.sha1, path,
 290                         e->stages[2].sha, &e->stages[2].mode);
 291         get_tree_entry(b->object.sha1, path,
 292                         e->stages[3].sha, &e->stages[3].mode);
 293         item = string_list_insert(path, entries);
 294         item->util = e;
 295         return e;
 296 }
 297
 298 /*
 299  * Create a dictionary mapping file names to stage_data objects. The
 300  * dictionary contains one entry for every path with a non-zero stage entry.
 301  */
 302 static struct string_list *get_unmerged(void)
 303 {
 304         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 305         int i;
 306
 307         unmerged->strdup_strings = 1;
 308
 309         for (i = 0; i < active_nr; i++) {
 310                 struct string_list_item *item;
 311                 struct stage_data *e;
 312                 struct cache_entry *ce = active_cache[i];
 313                 if (!ce_stage(ce))
 314                         continue;
 315
 316                 item = string_list_lookup(ce->name, unmerged);
 317                 if (!item) {
 318                         item = string_list_insert(ce->name, unmerged);
 319                         item->util = xcalloc(1, sizeof(struct stage_data));
 320                 }
 321                 e = item->util;
 322                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 323                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 324         }
 325
 326         return unmerged;
 327 }
 328
 329 struct rename
 330 {
 331         struct diff_filepair *pair;
 332         struct stage_data *src_entry;
 333         struct stage_data *dst_entry;
 334         unsigned processed:1;
 335 };
 336
 337 /*
 338  * Get information of all renames which occurred between 'o_tree' and
 339  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 340  * 'b_tree') to be able to associate the correct cache entries with
 341  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 342  */
 343 static struct string_list *get_renames(struct tree *tree,
 344                                         struct tree *o_tree,
 345                                         struct tree *a_tree,
 346                                         struct tree *b_tree,
 347                                         struct string_list *entries)
 348 {
 349         int i;
 350         struct string_list *renames;
 351         struct diff_options opts;
 352
 353         renames = xcalloc(1, sizeof(struct string_list));
 354         diff_setup(&opts);
 355         DIFF_OPT_SET(&opts, RECURSIVE);
 356         opts.detect_rename = DIFF_DETECT_RENAME;
 357         opts.rename_limit = merge_rename_limit >= 0 ? merge_rename_limit :
 358                             diff_rename_limit >= 0 ? diff_rename_limit :
 359                             500;
 360         opts.warn_on_too_large_rename = 1;
 361         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 362         if (diff_setup_done(&opts) < 0)
 363                 die("diff setup failed");
 364         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 365         diffcore_std(&opts);
 366         for (i = 0; i < diff_queued_diff.nr; ++i) {
 367                 struct string_list_item *item;
 368                 struct rename *re;
 369                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 370                 if (pair->status != 'R') {
 371                         diff_free_filepair(pair);
 372                         continue;
 373                 }
 374                 re = xmalloc(sizeof(*re));
 375                 re->processed = 0;
 376                 re->pair = pair;
 377                 item = string_list_lookup(re->pair->one->path, entries);
 378                 if (!item)
 379                         re->src_entry = insert_stage_data(re->pair->one->path,
 380                                         o_tree, a_tree, b_tree, entries);
 381                 else
 382                         re->src_entry = item->util;
 383
 384                 item = string_list_lookup(re->pair->two->path, entries);
 385                 if (!item)
 386                         re->dst_entry = insert_stage_data(re->pair->two->path,
 387                                         o_tree, a_tree, b_tree, entries);
 388                 else
 389                         re->dst_entry = item->util;
 390                 item = string_list_insert(pair->one->path, renames);
 391                 item->util = re;
 392         }
 393         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 394         diff_queued_diff.nr = 0;
 395         diff_flush(&opts);
 396         return renames;
 397 }
 398
 399 static int update_stages(const char *path, struct diff_filespec *o,
 400                          struct diff_filespec *a, struct diff_filespec *b,
 401                          int clear)
 402 {
 403         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 404         if (clear)
 405                 if (remove_file_from_cache(path))
 406                         return -1;
 407         if (o)
 408                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 409                         return -1;
 410         if (a)
 411                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 412                         return -1;
 413         if (b)
 414                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 415                         return -1;
 416         return 0;
 417 }
 418
 419 static int remove_path(const char *name)
 420 {
 421         int ret;
 422         char *slash, *dirs;
 423
 424         ret = unlink(name);
 425         if (ret)
 426                 return ret;
 427         dirs = xstrdup(name);
 428         while ((slash = strrchr(name, '/'))) {
 429                 *slash = '\0';
 430                 if (rmdir(name) != 0)
 431                         break;
 432         }
 433         free(dirs);
 434         return ret;
 435 }
 436
 437 static int remove_file(int clean, const char *path, int no_wd)
 438 {
 439         int update_cache = index_only || clean;
 440         int update_working_directory = !index_only && !no_wd;
 441
 442         if (update_cache) {
 443                 if (remove_file_from_cache(path))
 444                         return -1;
 445         }
 446         if (update_working_directory) {
 447                 if (remove_path(path) && errno != ENOENT)
 448                         return -1;
 449         }
 450         return 0;
 451 }
 452
 453 static char *unique_path(const char *path, const char *branch)
 454 {
 455         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 456         int suffix = 0;
 457         struct stat st;
 458         char *p = newpath + strlen(path);
 459         strcpy(newpath, path);
 460         *(p++) = '~';
 461         strcpy(p, branch);
 462         for (; *p; ++p)
 463                 if ('/' == *p)
 464                         *p = '_';
 465         while (string_list_has_string(&current_file_set, newpath) ||
 466                string_list_has_string(&current_directory_set, newpath) ||
 467                lstat(newpath, &st) == 0)
 468                 sprintf(p, "_%d", suffix++);
 469
 470         string_list_insert(newpath, &current_file_set);
 471         return newpath;
 472 }
 473
 474 static void flush_buffer(int fd, const char *buf, unsigned long size)
 475 {
 476         while (size > 0) {
 477                 long ret = write_in_full(fd, buf, size);
 478                 if (ret < 0) {
 479                         /* Ignore epipe */
 480                         if (errno == EPIPE)
 481                                 break;
 482                         die("merge-recursive: %s", strerror(errno));
 483                 } else if (!ret) {
 484                         die("merge-recursive: disk full?");
 485                 }
 486                 size -= ret;
 487                 buf += ret;
 488         }
 489 }
 490
 491 static int make_room_for_path(const char *path)
 492 {
 493         int status;
 494         const char *msg = "failed to create path '%s'%s";
 495
 496         status = safe_create_leading_directories_const(path);
 497         if (status) {
 498                 if (status == -3) {
 499                         /* something else exists */
 500                         error(msg, path, ": perhaps a D/F conflict?");
 501                         return -1;
 502                 }
 503                 die(msg, path, "");
 504         }
 505
 506         /* Successful unlink is good.. */
 507         if (!unlink(path))
 508                 return 0;
 509         /* .. and so is no existing file */
 510         if (errno == ENOENT)
 511                 return 0;
 512         /* .. but not some other error (who really cares what?) */
 513         return error(msg, path, ": perhaps a D/F conflict?");
 514 }
 515
 516 static void update_file_flags(const unsigned char *sha,
 517                               unsigned mode,
 518                               const char *path,
 519                               int update_cache,
 520                               int update_wd)
 521 {
 522         if (index_only)
 523                 update_wd = 0;
 524
 525         if (update_wd) {
 526                 enum object_type type;
 527                 void *buf;
 528                 unsigned long size;
 529
 530                 if (S_ISGITLINK(mode))
 531                         die("cannot read object %s '%s': It is a submodule!",
 532                             sha1_to_hex(sha), path);
 533
 534                 buf = read_sha1_file(sha, &type, &size);
 535                 if (!buf)
 536                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 537                 if (type != OBJ_BLOB)
 538                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 539                 if (S_ISREG(mode)) {
 540                         struct strbuf strbuf;
 541                         strbuf_init(&strbuf, 0);
 542                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 543                                 free(buf);
 544                                 size = strbuf.len;
 545                                 buf = strbuf_detach(&strbuf, NULL);
 546                         }
 547                 }
 548
 549                 if (make_room_for_path(path) < 0) {
 550                         update_wd = 0;
 551                         free(buf);
 552                         goto update_index;
 553                 }
 554                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 555                         int fd;
 556                         if (mode & 0100)
 557                                 mode = 0777;
 558                         else
 559                                 mode = 0666;
 560                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 561                         if (fd < 0)
 562                                 die("failed to open %s: %s", path, strerror(errno));
 563                         flush_buffer(fd, buf, size);
 564                         close(fd);
 565                 } else if (S_ISLNK(mode)) {
 566                         char *lnk = xmemdupz(buf, size);
 567                         safe_create_leading_directories_const(path);
 568                         unlink(path);
 569                         symlink(lnk, path);
 570                         free(lnk);
 571                 } else
 572                         die("do not know what to do with %06o %s '%s'",
 573                             mode, sha1_to_hex(sha), path);
 574                 free(buf);
 575         }
 576  update_index:
 577         if (update_cache)
 578                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 579 }
 580
 581 static void update_file(int clean,
 582                         const unsigned char *sha,
 583                         unsigned mode,
 584                         const char *path)
 585 {
 586         update_file_flags(sha, mode, path, index_only || clean, !index_only);
 587 }
 588
 589 /* Low level file merging, update and removal */
 590
 591 struct merge_file_info
 592 {
 593         unsigned char sha[20];
 594         unsigned mode;
 595         unsigned clean:1,
 596                  merge:1;
 597 };
 598
 599 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 600 {
 601         unsigned long size;
 602         enum object_type type;
 603
 604         if (!hashcmp(sha1, null_sha1)) {
 605                 mm->ptr = xstrdup("");
 606                 mm->size = 0;
 607                 return;
 608         }
 609
 610         mm->ptr = read_sha1_file(sha1, &type, &size);
 611         if (!mm->ptr || type != OBJ_BLOB)
 612                 die("unable to read blob object %s", sha1_to_hex(sha1));
 613         mm->size = size;
 614 }
 615
 616 static int merge_3way(mmbuffer_t *result_buf,
 617                       struct diff_filespec *o,
 618                       struct diff_filespec *a,
 619                       struct diff_filespec *b,
 620                       const char *branch1,
 621                       const char *branch2)
 622 {
 623         mmfile_t orig, src1, src2;
 624         char *name1, *name2;
 625         int merge_status;
 626
 627         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 628         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 629
 630         fill_mm(o->sha1, &orig);
 631         fill_mm(a->sha1, &src1);
 632         fill_mm(b->sha1, &src2);
 633
 634         merge_status = ll_merge(result_buf, a->path, &orig,
 635                                 &src1, name1, &src2, name2,
 636                                 index_only);
 637
 638         free(name1);
 639         free(name2);
 640         free(orig.ptr);
 641         free(src1.ptr);
 642         free(src2.ptr);
 643         return merge_status;
 644 }
 645
 646 static struct merge_file_info merge_file(struct diff_filespec *o,
 647                 struct diff_filespec *a, struct diff_filespec *b,
 648                 const char *branch1, const char *branch2)
 649 {
 650         struct merge_file_info result;
 651         result.merge = 0;
 652         result.clean = 1;
 653
 654         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 655                 result.clean = 0;
 656                 if (S_ISREG(a->mode)) {
 657                         result.mode = a->mode;
 658                         hashcpy(result.sha, a->sha1);
 659                 } else {
 660                         result.mode = b->mode;
 661                         hashcpy(result.sha, b->sha1);
 662                 }
 663         } else {
 664                 if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 665                         result.merge = 1;
 666
 667                 /*
 668                  * Merge modes
 669                  */
 670                 if (a->mode == b->mode || a->mode == o->mode)
 671                         result.mode = b->mode;
 672                 else {
 673                         result.mode = a->mode;
 674                         if (b->mode != o->mode) {
 675                                 result.clean = 0;
 676                                 result.merge = 1;
 677                         }
 678                 }
 679
 680                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, o->sha1))
 681                         hashcpy(result.sha, b->sha1);
 682                 else if (sha_eq(b->sha1, o->sha1))
 683                         hashcpy(result.sha, a->sha1);
 684                 else if (S_ISREG(a->mode)) {
 685                         mmbuffer_t result_buf;
 686                         int merge_status;
 687
 688                         merge_status = merge_3way(&result_buf, o, a, b,
 689                                                   branch1, branch2);
 690
 691                         if ((merge_status < 0) || !result_buf.ptr)
 692                                 die("Failed to execute internal merge");
 693
 694                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 695                                             blob_type, result.sha))
 696                                 die("Unable to add %s to database",
 697                                     a->path);
 698
 699                         free(result_buf.ptr);
 700                         result.clean = (merge_status == 0);
 701                 } else if (S_ISGITLINK(a->mode)) {
 702                         result.clean = 0;
 703                         hashcpy(result.sha, a->sha1);
 704                 } else if (S_ISLNK(a->mode)) {
 705                         hashcpy(result.sha, a->sha1);
 706
 707                         if (!sha_eq(a->sha1, b->sha1))
 708                                 result.clean = 0;
 709                 } else {
 710                         die("unsupported object type in the tree");
 711                 }
 712         }
 713
 714         return result;
 715 }
 716
 717 static void conflict_rename_rename(struct rename *ren1,
 718                                    const char *branch1,
 719                                    struct rename *ren2,
 720                                    const char *branch2)
 721 {
 722         char *del[2];
 723         int delp = 0;
 724         const char *ren1_dst = ren1->pair->two->path;
 725         const char *ren2_dst = ren2->pair->two->path;
 726         const char *dst_name1 = ren1_dst;
 727         const char *dst_name2 = ren2_dst;
 728         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 729                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 730                 output(1, "%s is a directory in %s added as %s instead",
 731                        ren1_dst, branch2, dst_name1);
 732                 remove_file(0, ren1_dst, 0);
 733         }
 734         if (string_list_has_string(&current_directory_set, ren2_dst)) {
 735                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 736                 output(1, "%s is a directory in %s added as %s instead",
 737                        ren2_dst, branch1, dst_name2);
 738                 remove_file(0, ren2_dst, 0);
 739         }
 740         if (index_only) {
 741                 remove_file_from_cache(dst_name1);
 742                 remove_file_from_cache(dst_name2);
 743                 /*
 744                  * Uncomment to leave the conflicting names in the resulting tree
 745                  *
 746                  * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 747                  * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 748                  */
 749         } else {
 750                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 751                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 752         }
 753         while (delp--)
 754                 free(del[delp]);
 755 }
 756
 757 static void conflict_rename_dir(struct rename *ren1,
 758                                 const char *branch1)
 759 {
 760         char *new_path = unique_path(ren1->pair->two->path, branch1);
 761         output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
 762         remove_file(0, ren1->pair->two->path, 0);
 763         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 764         free(new_path);
 765 }
 766
 767 static void conflict_rename_rename_2(struct rename *ren1,
 768                                      const char *branch1,
 769                                      struct rename *ren2,
 770                                      const char *branch2)
 771 {
 772         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 773         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 774         output(1, "Renamed %s to %s and %s to %s instead",
 775                ren1->pair->one->path, new_path1,
 776                ren2->pair->one->path, new_path2);
 777         remove_file(0, ren1->pair->two->path, 0);
 778         update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 779         update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 780         free(new_path2);
 781         free(new_path1);
 782 }
 783
 784 static int process_renames(struct string_list *a_renames,
 785                            struct string_list *b_renames,
 786                            const char *a_branch,
 787                            const char *b_branch)
 788 {
 789         int clean_merge = 1, i, j;
 790         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 791         const struct rename *sre;
 792
 793         for (i = 0; i < a_renames->nr; i++) {
 794                 sre = a_renames->items[i].util;
 795                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 796                         = sre->dst_entry;
 797         }
 798         for (i = 0; i < b_renames->nr; i++) {
 799                 sre = b_renames->items[i].util;
 800                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 801                         = sre->dst_entry;
 802         }
 803
 804         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 805                 int compare;
 806                 char *src;
 807                 struct string_list *renames1, *renames2, *renames2Dst;
 808                 struct rename *ren1 = NULL, *ren2 = NULL;
 809                 const char *branch1, *branch2;
 810                 const char *ren1_src, *ren1_dst;
 811
 812                 if (i >= a_renames->nr) {
 813                         compare = 1;
 814                         ren2 = b_renames->items[j++].util;
 815                 } else if (j >= b_renames->nr) {
 816                         compare = -1;
 817                         ren1 = a_renames->items[i++].util;
 818                 } else {
 819                         compare = strcmp(a_renames->items[i].string,
 820                                         b_renames->items[j].string);
 821                         if (compare <= 0)
 822                                 ren1 = a_renames->items[i++].util;
 823                         if (compare >= 0)
 824                                 ren2 = b_renames->items[j++].util;
 825                 }
 826
 827                 /* TODO: refactor, so that 1/2 are not needed */
 828                 if (ren1) {
 829                         renames1 = a_renames;
 830                         renames2 = b_renames;
 831                         renames2Dst = &b_by_dst;
 832                         branch1 = a_branch;
 833                         branch2 = b_branch;
 834                 } else {
 835                         struct rename *tmp;
 836                         renames1 = b_renames;
 837                         renames2 = a_renames;
 838                         renames2Dst = &a_by_dst;
 839                         branch1 = b_branch;
 840                         branch2 = a_branch;
 841                         tmp = ren2;
 842                         ren2 = ren1;
 843                         ren1 = tmp;
 844                 }
 845                 src = ren1->pair->one->path;
 846
 847                 ren1->dst_entry->processed = 1;
 848                 ren1->src_entry->processed = 1;
 849
 850                 if (ren1->processed)
 851                         continue;
 852                 ren1->processed = 1;
 853
 854                 ren1_src = ren1->pair->one->path;
 855                 ren1_dst = ren1->pair->two->path;
 856
 857                 if (ren2) {
 858                         const char *ren2_src = ren2->pair->one->path;
 859                         const char *ren2_dst = ren2->pair->two->path;
 860                         /* Renamed in 1 and renamed in 2 */
 861                         if (strcmp(ren1_src, ren2_src) != 0)
 862                                 die("ren1.src != ren2.src");
 863                         ren2->dst_entry->processed = 1;
 864                         ren2->processed = 1;
 865                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 866                                 clean_merge = 0;
 867                                 output(1, "CONFLICT (rename/rename): "
 868                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 869                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 870                                        src, ren1_dst, branch1,
 871                                        src, ren2_dst, branch2,
 872                                        index_only ? " (left unresolved)": "");
 873                                 if (index_only) {
 874                                         remove_file_from_cache(src);
 875                                         update_file(0, ren1->pair->one->sha1,
 876                                                     ren1->pair->one->mode, src);
 877                                 }
 878                                 conflict_rename_rename(ren1, branch1, ren2, branch2);
 879                         } else {
 880                                 struct merge_file_info mfi;
 881                                 remove_file(1, ren1_src, 1);
 882                                 mfi = merge_file(ren1->pair->one,
 883                                                  ren1->pair->two,
 884                                                  ren2->pair->two,
 885                                                  branch1,
 886                                                  branch2);
 887                                 if (mfi.merge || !mfi.clean)
 888                                         output(1, "Renamed %s->%s", src, ren1_dst);
 889
 890                                 if (mfi.merge)
 891                                         output(2, "Auto-merged %s", ren1_dst);
 892
 893                                 if (!mfi.clean) {
 894                                         output(1, "CONFLICT (content): merge conflict in %s",
 895                                                ren1_dst);
 896                                         clean_merge = 0;
 897
 898                                         if (!index_only)
 899                                                 update_stages(ren1_dst,
 900                                                               ren1->pair->one,
 901                                                               ren1->pair->two,
 902                                                               ren2->pair->two,
 903                                                               1 /* clear */);
 904                                 }
 905                                 update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 906                         }
 907                 } else {
 908                         /* Renamed in 1, maybe changed in 2 */
 909                         struct string_list_item *item;
 910                         /* we only use sha1 and mode of these */
 911                         struct diff_filespec src_other, dst_other;
 912                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 913
 914                         remove_file(1, ren1_src, index_only || stage == 3);
 915
 916                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 917                         src_other.mode = ren1->src_entry->stages[stage].mode;
 918                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 919                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 920
 921                         try_merge = 0;
 922
 923                         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 924                                 clean_merge = 0;
 925                                 output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
 926                                        " directory %s added in %s",
 927                                        ren1_src, ren1_dst, branch1,
 928                                        ren1_dst, branch2);
 929                                 conflict_rename_dir(ren1, branch1);
 930                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 931                                 clean_merge = 0;
 932                                 output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
 933                                        "and deleted in %s",
 934                                        ren1_src, ren1_dst, branch1,
 935                                        branch2);
 936                                 update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 937                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 938                                 const char *new_path;
 939                                 clean_merge = 0;
 940                                 try_merge = 1;
 941                                 output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
 942                                        "%s added in %s",
 943                                        ren1_src, ren1_dst, branch1,
 944                                        ren1_dst, branch2);
 945                                 new_path = unique_path(ren1_dst, branch2);
 946                                 output(1, "Added as %s instead", new_path);
 947                                 update_file(0, dst_other.sha1, dst_other.mode, new_path);
 948                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 949                                 ren2 = item->util;
 950                                 clean_merge = 0;
 951                                 ren2->processed = 1;
 952                                 output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
 953                                        "Renamed %s->%s in %s",
 954                                        ren1_src, ren1_dst, branch1,
 955                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 956                                 conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 957                         } else
 958                                 try_merge = 1;
 959
 960                         if (try_merge) {
 961                                 struct diff_filespec *o, *a, *b;
 962                                 struct merge_file_info mfi;
 963                                 src_other.path = (char *)ren1_src;
 964
 965                                 o = ren1->pair->one;
 966                                 if (a_renames == renames1) {
 967                                         a = ren1->pair->two;
 968                                         b = &src_other;
 969                                 } else {
 970                                         b = ren1->pair->two;
 971                                         a = &src_other;
 972                                 }
 973                                 mfi = merge_file(o, a, b,
 974                                                 a_branch, b_branch);
 975
 976                                 if (mfi.clean &&
 977                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
 978                                     mfi.mode == ren1->pair->two->mode)
 979                                         /*
 980                                          * This messaged is part of
 981                                          * t6022 test. If you change
 982                                          * it update the test too.
 983                                          */
 984                                         output(3, "Skipped %s (merged same as existing)", ren1_dst);
 985                                 else {
 986                                         if (mfi.merge || !mfi.clean)
 987                                                 output(1, "Renamed %s => %s", ren1_src, ren1_dst);
 988                                         if (mfi.merge)
 989                                                 output(2, "Auto-merged %s", ren1_dst);
 990                                         if (!mfi.clean) {
 991                                                 output(1, "CONFLICT (rename/modify): Merge conflict in %s",
 992                                                        ren1_dst);
 993                                                 clean_merge = 0;
 994
 995                                                 if (!index_only)
 996                                                         update_stages(ren1_dst,
 997                                                                       o, a, b, 1);
 998                                         }
 999                                         update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1000                                 }
1001                         }
1002                 }
1003         }
1004         string_list_clear(&a_by_dst, 0);
1005         string_list_clear(&b_by_dst, 0);
1006
1007         return clean_merge;
1008 }
1009
1010 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1011 {
1012         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1013 }
1014
1015 /* Per entry merge function */
1016 static int process_entry(const char *path, struct stage_data *entry,
1017                          const char *branch1,
1018                          const char *branch2)
1019 {
1020         /*
1021         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1022         print_index_entry("\tpath: ", entry);
1023         */
1024         int clean_merge = 1;
1025         unsigned o_mode = entry->stages[1].mode;
1026         unsigned a_mode = entry->stages[2].mode;
1027         unsigned b_mode = entry->stages[3].mode;
1028         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1029         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1030         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1031
1032         if (o_sha && (!a_sha || !b_sha)) {
1033                 /* Case A: Deleted in one */
1034                 if ((!a_sha && !b_sha) ||
1035                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1036                     (!a_sha && sha_eq(b_sha, o_sha))) {
1037                         /* Deleted in both or deleted in one and
1038                          * unchanged in the other */
1039                         if (a_sha)
1040                                 output(2, "Removed %s", path);
1041                         /* do not touch working file if it did not exist */
1042                         remove_file(1, path, !a_sha);
1043                 } else {
1044                         /* Deleted in one and changed in the other */
1045                         clean_merge = 0;
1046                         if (!a_sha) {
1047                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1048                                        "and modified in %s. Version %s of %s left in tree.",
1049                                        path, branch1,
1050                                        branch2, branch2, path);
1051                                 update_file(0, b_sha, b_mode, path);
1052                         } else {
1053                                 output(1, "CONFLICT (delete/modify): %s deleted in %s "
1054                                        "and modified in %s. Version %s of %s left in tree.",
1055                                        path, branch2,
1056                                        branch1, branch1, path);
1057                                 update_file(0, a_sha, a_mode, path);
1058                         }
1059                 }
1060
1061         } else if ((!o_sha && a_sha && !b_sha) ||
1062                    (!o_sha && !a_sha && b_sha)) {
1063                 /* Case B: Added in one. */
1064                 const char *add_branch;
1065                 const char *other_branch;
1066                 unsigned mode;
1067                 const unsigned char *sha;
1068                 const char *conf;
1069
1070                 if (a_sha) {
1071                         add_branch = branch1;
1072                         other_branch = branch2;
1073                         mode = a_mode;
1074                         sha = a_sha;
1075                         conf = "file/directory";
1076                 } else {
1077                         add_branch = branch2;
1078                         other_branch = branch1;
1079                         mode = b_mode;
1080                         sha = b_sha;
1081                         conf = "directory/file";
1082                 }
1083                 if (string_list_has_string(&current_directory_set, path)) {
1084                         const char *new_path = unique_path(path, add_branch);
1085                         clean_merge = 0;
1086                         output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1087                                "Added %s as %s",
1088                                conf, path, other_branch, path, new_path);
1089                         remove_file(0, path, 0);
1090                         update_file(0, sha, mode, new_path);
1091                 } else {
1092                         output(2, "Added %s", path);
1093                         update_file(1, sha, mode, path);
1094                 }
1095         } else if (a_sha && b_sha) {
1096                 /* Case C: Added in both (check for same permissions) and */
1097                 /* case D: Modified in both, but differently. */
1098                 const char *reason = "content";
1099                 struct merge_file_info mfi;
1100                 struct diff_filespec o, a, b;
1101
1102                 if (!o_sha) {
1103                         reason = "add/add";
1104                         o_sha = (unsigned char *)null_sha1;
1105                 }
1106                 output(2, "Auto-merged %s", path);
1107                 o.path = a.path = b.path = (char *)path;
1108                 hashcpy(o.sha1, o_sha);
1109                 o.mode = o_mode;
1110                 hashcpy(a.sha1, a_sha);
1111                 a.mode = a_mode;
1112                 hashcpy(b.sha1, b_sha);
1113                 b.mode = b_mode;
1114
1115                 mfi = merge_file(&o, &a, &b,
1116                                  branch1, branch2);
1117
1118                 clean_merge = mfi.clean;
1119                 if (mfi.clean)
1120                         update_file(1, mfi.sha, mfi.mode, path);
1121                 else if (S_ISGITLINK(mfi.mode))
1122                         output(1, "CONFLICT (submodule): Merge conflict in %s "
1123                                "- needs %s", path, sha1_to_hex(b.sha1));
1124                 else {
1125                         output(1, "CONFLICT (%s): Merge conflict in %s",
1126                                         reason, path);
1127
1128                         if (index_only)
1129                                 update_file(0, mfi.sha, mfi.mode, path);
1130                         else
1131                                 update_file_flags(mfi.sha, mfi.mode, path,
1132                                               0 /* update_cache */, 1 /* update_working_directory */);
1133                 }
1134         } else if (!o_sha && !a_sha && !b_sha) {
1135                 /*
1136                  * this entry was deleted altogether. a_mode == 0 means
1137                  * we had that path and want to actively remove it.
1138                  */
1139                 remove_file(1, path, !a_mode);
1140         } else
1141                 die("Fatal merge failure, shouldn't happen.");
1142
1143         return clean_merge;
1144 }
1145
1146 int merge_trees(struct tree *head,
1147                 struct tree *merge,
1148                 struct tree *common,
1149                 const char *branch1,
1150                 const char *branch2,
1151                 struct tree **result)
1152 {
1153         int code, clean;
1154
1155         if (subtree_merge) {
1156                 merge = shift_tree_object(head, merge);
1157                 common = shift_tree_object(head, common);
1158         }
1159
1160         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1161                 output(0, "Already uptodate!");
1162                 *result = head;
1163                 return 1;
1164         }
1165
1166         code = git_merge_trees(index_only, common, head, merge);
1167
1168         if (code != 0)
1169                 die("merging of trees %s and %s failed",
1170                     sha1_to_hex(head->object.sha1),
1171                     sha1_to_hex(merge->object.sha1));
1172
1173         if (unmerged_cache()) {
1174                 struct string_list *entries, *re_head, *re_merge;
1175                 int i;
1176                 string_list_clear(&current_file_set, 1);
1177                 string_list_clear(&current_directory_set, 1);
1178                 get_files_dirs(head);
1179                 get_files_dirs(merge);
1180
1181                 entries = get_unmerged();
1182                 re_head  = get_renames(head, common, head, merge, entries);
1183                 re_merge = get_renames(merge, common, head, merge, entries);
1184                 clean = process_renames(re_head, re_merge,
1185                                 branch1, branch2);
1186                 for (i = 0; i < entries->nr; i++) {
1187                         const char *path = entries->items[i].string;
1188                         struct stage_data *e = entries->items[i].util;
1189                         if (!e->processed
1190                                 && !process_entry(path, e, branch1, branch2))
1191                                 clean = 0;
1192                 }
1193
1194                 string_list_clear(re_merge, 0);
1195                 string_list_clear(re_head, 0);
1196                 string_list_clear(entries, 1);
1197
1198         }
1199         else
1200                 clean = 1;
1201
1202         if (index_only)
1203                 *result = write_tree_from_memory();
1204
1205         return clean;
1206 }
1207
1208 static struct commit_list *reverse_commit_list(struct commit_list *list)
1209 {
1210         struct commit_list *next = NULL, *current, *backup;
1211         for (current = list; current; current = backup) {
1212                 backup = current->next;
1213                 current->next = next;
1214                 next = current;
1215         }
1216         return next;
1217 }
1218
1219 /*
1220  * Merge the commits h1 and h2, return the resulting virtual
1221  * commit object and a flag indicating the cleanness of the merge.
1222  */
1223 int merge_recursive(struct commit *h1,
1224                     struct commit *h2,
1225                     const char *branch1,
1226                     const char *branch2,
1227                     struct commit_list *ca,
1228                     struct commit **result)
1229 {
1230         struct commit_list *iter;
1231         struct commit *merged_common_ancestors;
1232         struct tree *mrtree = mrtree;
1233         int clean;
1234
1235         if (show(4)) {
1236                 output(4, "Merging:");
1237                 output_commit_title(h1);
1238                 output_commit_title(h2);
1239         }
1240
1241         if (!ca) {
1242                 ca = get_merge_bases(h1, h2, 1);
1243                 ca = reverse_commit_list(ca);
1244         }
1245
1246         if (show(5)) {
1247                 output(5, "found %u common ancestor(s):", commit_list_count(ca));
1248                 for (iter = ca; iter; iter = iter->next)
1249                         output_commit_title(iter->item);
1250         }
1251
1252         merged_common_ancestors = pop_commit(&ca);
1253         if (merged_common_ancestors == NULL) {
1254                 /* if there is no common ancestor, make an empty tree */
1255                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1256
1257                 tree->object.parsed = 1;
1258                 tree->object.type = OBJ_TREE;
1259                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1260                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1261         }
1262
1263         for (iter = ca; iter; iter = iter->next) {
1264                 call_depth++;
1265                 /*
1266                  * When the merge fails, the result contains files
1267                  * with conflict markers. The cleanness flag is
1268                  * ignored, it was never actually used, as result of
1269                  * merge_trees has always overwritten it: the committed
1270                  * "conflicts" were already resolved.
1271                  */
1272                 discard_cache();
1273                 merge_recursive(merged_common_ancestors, iter->item,
1274                                 "Temporary merge branch 1",
1275                                 "Temporary merge branch 2",
1276                                 NULL,
1277                                 &merged_common_ancestors);
1278                 call_depth--;
1279
1280                 if (!merged_common_ancestors)
1281                         die("merge returned no commit");
1282         }
1283
1284         discard_cache();
1285         if (!call_depth) {
1286                 read_cache();
1287                 index_only = 0;
1288         } else
1289                 index_only = 1;
1290
1291         clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1292                             branch1, branch2, &mrtree);
1293
1294         if (index_only) {
1295                 *result = make_virtual_commit(mrtree, "merged tree");
1296                 commit_list_insert(h1, &(*result)->parents);
1297                 commit_list_insert(h2, &(*result)->parents->next);
1298         }
1299         flush_output();
1300         return clean;
1301 }
1302
1303 static const char *better_branch_name(const char *branch)
1304 {
1305         static char githead_env[8 + 40 + 1];
1306         char *name;
1307
1308         if (strlen(branch) != 40)
1309                 return branch;
1310         sprintf(githead_env, "GITHEAD_%s", branch);
1311         name = getenv(githead_env);
1312         return name ? name : branch;
1313 }
1314
1315 static struct commit *get_ref(const char *ref)
1316 {
1317         unsigned char sha1[20];
1318         struct object *object;
1319
1320         if (get_sha1(ref, sha1))
1321                 die("Could not resolve ref '%s'", ref);
1322         object = deref_tag(parse_object(sha1), ref, strlen(ref));
1323         if (!object)
1324                 return NULL;
1325         if (object->type == OBJ_TREE)
1326                 return make_virtual_commit((struct tree*)object,
1327                         better_branch_name(ref));
1328         if (object->type != OBJ_COMMIT)
1329                 return NULL;
1330         if (parse_commit((struct commit *)object))
1331                 die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1332         return (struct commit *)object;
1333 }
1334
1335 static int merge_config(const char *var, const char *value, void *cb)
1336 {
1337         if (!strcasecmp(var, "merge.verbosity")) {
1338                 verbosity = git_config_int(var, value);
1339                 return 0;
1340         }
1341         if (!strcasecmp(var, "diff.renamelimit")) {
1342                 diff_rename_limit = git_config_int(var, value);
1343                 return 0;
1344         }
1345         if (!strcasecmp(var, "merge.renamelimit")) {
1346                 merge_rename_limit = git_config_int(var, value);
1347                 return 0;
1348         }
1349         return git_default_config(var, value, cb);
1350 }
1351
1352 int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
1353 {
1354         static const char *bases[20];
1355         static unsigned bases_count = 0;
1356         int i, clean;
1357         const char *branch1, *branch2;
1358         struct commit *result, *h1, *h2;
1359         struct commit_list *ca = NULL;
1360         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1361         int index_fd;
1362
1363         if (argv[0]) {
1364                 int namelen = strlen(argv[0]);
1365                 if (8 < namelen &&
1366                     !strcmp(argv[0] + namelen - 8, "-subtree"))
1367                         subtree_merge = 1;
1368         }
1369
1370         git_config(merge_config, NULL);
1371         if (getenv("GIT_MERGE_VERBOSITY"))
1372                 verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1373
1374         if (argc < 4)
1375                 die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1376
1377         for (i = 1; i < argc; ++i) {
1378                 if (!strcmp(argv[i], "--"))
1379                         break;
1380                 if (bases_count < sizeof(bases)/sizeof(*bases))
1381                         bases[bases_count++] = argv[i];
1382         }
1383         if (argc - i != 3) /* "--" "<head>" "<remote>" */
1384                 die("Not handling anything other than two heads merge.");
1385         if (verbosity >= 5)
1386                 buffer_output = 0;
1387
1388         branch1 = argv[++i];
1389         branch2 = argv[++i];
1390
1391         h1 = get_ref(branch1);
1392         h2 = get_ref(branch2);
1393
1394         branch1 = better_branch_name(branch1);
1395         branch2 = better_branch_name(branch2);
1396
1397         if (show(3))
1398                 printf("Merging %s with %s\n", branch1, branch2);
1399
1400         index_fd = hold_locked_index(lock, 1);
1401
1402         for (i = 0; i < bases_count; i++) {
1403                 struct commit *ancestor = get_ref(bases[i]);
1404                 ca = commit_list_insert(ancestor, &ca);
1405         }
1406         clean = merge_recursive(h1, h2, branch1, branch2, ca, &result);
1407
1408         if (active_cache_changed &&
1409             (write_cache(index_fd, active_cache, active_nr) ||
1410              commit_locked_index(lock)))
1411                         die ("unable to write %s", get_index_file());
1412
1413         return clean ? 0: 1;
1414 }