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

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "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 "attr.h"
  20 #include "merge-recursive.h"
  21 #include "dir.h"
  22
  23 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  24 {
  25         unsigned char shifted[20];
  26
  27         /*
  28          * NEEDSWORK: this limits the recursion depth to hardcoded
  29          * value '2' to avoid excessive overhead.
  30          */
  31         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  32         if (!hashcmp(two->object.sha1, shifted))
  33                 return two;
  34         return lookup_tree(shifted);
  35 }
  36
  37 /*
  38  * A virtual commit has (const char *)commit->util set to the name.
  39  */
  40
  41 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  42 {
  43         struct commit *commit = xcalloc(1, sizeof(struct commit));
  44         commit->tree = tree;
  45         commit->util = (void*)comment;
  46         /* avoid warnings */
  47         commit->object.parsed = 1;
  48         return commit;
  49 }
  50
  51 /*
  52  * Since we use get_tree_entry(), which does not put the read object into
  53  * the object pool, we cannot rely on a == b.
  54  */
  55 static int sha_eq(const unsigned char *a, const unsigned char *b)
  56 {
  57         if (!a && !b)
  58                 return 2;
  59         return a && b && hashcmp(a, b) == 0;
  60 }
  61
  62 /*
  63  * Since we want to write the index eventually, we cannot reuse the index
  64  * for these (temporary) data.
  65  */
  66 struct stage_data
  67 {
  68         struct
  69         {
  70                 unsigned mode;
  71                 unsigned char sha[20];
  72         } stages[4];
  73         unsigned processed:1;
  74 };
  75
  76 static int show(struct merge_options *o, int v)
  77 {
  78         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  79 }
  80
  81 static void flush_output(struct merge_options *o)
  82 {
  83         if (o->obuf.len) {
  84                 fputs(o->obuf.buf, stdout);
  85                 strbuf_reset(&o->obuf);
  86         }
  87 }
  88
  89 static void output(struct merge_options *o, int v, const char *fmt, ...)
  90 {
  91         int len;
  92         va_list ap;
  93
  94         if (!show(o, v))
  95                 return;
  96
  97         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
  98         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
  99         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 100
 101         va_start(ap, fmt);
 102         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 103         va_end(ap);
 104
 105         if (len < 0)
 106                 len = 0;
 107         if (len >= strbuf_avail(&o->obuf)) {
 108                 strbuf_grow(&o->obuf, len + 2);
 109                 va_start(ap, fmt);
 110                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 111                 va_end(ap);
 112                 if (len >= strbuf_avail(&o->obuf)) {
 113                         die("this should not happen, your snprintf is broken");
 114                 }
 115         }
 116         strbuf_setlen(&o->obuf, o->obuf.len + len);
 117         strbuf_add(&o->obuf, "\n", 1);
 118         if (!o->buffer_output)
 119                 flush_output(o);
 120 }
 121
 122 static void output_commit_title(struct merge_options *o, struct commit *commit)
 123 {
 124         int i;
 125         flush_output(o);
 126         for (i = o->call_depth; i--;)
 127                 fputs("  ", stdout);
 128         if (commit->util)
 129                 printf("virtual %s\n", (char *)commit->util);
 130         else {
 131                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 132                 if (parse_commit(commit) != 0)
 133                         printf("(bad commit)\n");
 134                 else {
 135                         const char *s;
 136                         int len;
 137                         for (s = commit->buffer; *s; s++)
 138                                 if (*s == '\n' && s[1] == '\n') {
 139                                         s += 2;
 140                                         break;
 141                                 }
 142                         for (len = 0; s[len] && '\n' != s[len]; len++)
 143                                 ; /* do nothing */
 144                         printf("%.*s\n", len, s);
 145                 }
 146         }
 147 }
 148
 149 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 150                 const char *path, int stage, int refresh, int options)
 151 {
 152         struct cache_entry *ce;
 153         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 154         if (!ce)
 155                 return error("addinfo_cache failed for path '%s'", path);
 156         return add_cache_entry(ce, options);
 157 }
 158
 159 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 160 {
 161         parse_tree(tree);
 162         init_tree_desc(desc, tree->buffer, tree->size);
 163 }
 164
 165 static int git_merge_trees(int index_only,
 166                            struct tree *common,
 167                            struct tree *head,
 168                            struct tree *merge)
 169 {
 170         int rc;
 171         struct tree_desc t[3];
 172         struct unpack_trees_options opts;
 173         static const struct unpack_trees_error_msgs msgs = {
 174                 /* would_overwrite */
 175                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
 176                 /* not_uptodate_file */
 177                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
 178                 /* not_uptodate_dir */
 179                 "Updating '%s' would lose untracked files in it.  Aborting.",
 180                 /* would_lose_untracked */
 181                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
 182                 /* bind_overlap -- will not happen here */
 183                 NULL,
 184         };
 185
 186         memset(&opts, 0, sizeof(opts));
 187         if (index_only)
 188                 opts.index_only = 1;
 189         else
 190                 opts.update = 1;
 191         opts.merge = 1;
 192         opts.head_idx = 2;
 193         opts.fn = threeway_merge;
 194         opts.src_index = &the_index;
 195         opts.dst_index = &the_index;
 196         opts.msgs = msgs;
 197
 198         init_tree_desc_from_tree(t+0, common);
 199         init_tree_desc_from_tree(t+1, head);
 200         init_tree_desc_from_tree(t+2, merge);
 201
 202         rc = unpack_trees(3, t, &opts);
 203         cache_tree_free(&active_cache_tree);
 204         return rc;
 205 }
 206
 207 struct tree *write_tree_from_memory(struct merge_options *o)
 208 {
 209         struct tree *result = NULL;
 210
 211         if (unmerged_cache()) {
 212                 int i;
 213                 output(o, 0, "There are unmerged index entries:");
 214                 for (i = 0; i < active_nr; i++) {
 215                         struct cache_entry *ce = active_cache[i];
 216                         if (ce_stage(ce))
 217                                 output(o, 0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 218                 }
 219                 return NULL;
 220         }
 221
 222         if (!active_cache_tree)
 223                 active_cache_tree = cache_tree();
 224
 225         if (!cache_tree_fully_valid(active_cache_tree) &&
 226             cache_tree_update(active_cache_tree,
 227                               active_cache, active_nr, 0, 0) < 0)
 228                 die("error building trees");
 229
 230         result = lookup_tree(active_cache_tree->sha1);
 231
 232         return result;
 233 }
 234
 235 static int save_files_dirs(const unsigned char *sha1,
 236                 const char *base, int baselen, const char *path,
 237                 unsigned int mode, int stage, void *context)
 238 {
 239         int len = strlen(path);
 240         char *newpath = xmalloc(baselen + len + 1);
 241         struct merge_options *o = context;
 242
 243         memcpy(newpath, base, baselen);
 244         memcpy(newpath + baselen, path, len);
 245         newpath[baselen + len] = '\0';
 246
 247         if (S_ISDIR(mode))
 248                 string_list_insert(newpath, &o->current_directory_set);
 249         else
 250                 string_list_insert(newpath, &o->current_file_set);
 251         free(newpath);
 252
 253         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 254 }
 255
 256 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 257 {
 258         int n;
 259         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 260                 return 0;
 261         n = o->current_file_set.nr + o->current_directory_set.nr;
 262         return n;
 263 }
 264
 265 /*
 266  * Returns an index_entry instance which doesn't have to correspond to
 267  * a real cache entry in Git's index.
 268  */
 269 static struct stage_data *insert_stage_data(const char *path,
 270                 struct tree *o, struct tree *a, struct tree *b,
 271                 struct string_list *entries)
 272 {
 273         struct string_list_item *item;
 274         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 275         get_tree_entry(o->object.sha1, path,
 276                         e->stages[1].sha, &e->stages[1].mode);
 277         get_tree_entry(a->object.sha1, path,
 278                         e->stages[2].sha, &e->stages[2].mode);
 279         get_tree_entry(b->object.sha1, path,
 280                         e->stages[3].sha, &e->stages[3].mode);
 281         item = string_list_insert(path, entries);
 282         item->util = e;
 283         return e;
 284 }
 285
 286 /*
 287  * Create a dictionary mapping file names to stage_data objects. The
 288  * dictionary contains one entry for every path with a non-zero stage entry.
 289  */
 290 static struct string_list *get_unmerged(void)
 291 {
 292         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 293         int i;
 294
 295         unmerged->strdup_strings = 1;
 296
 297         for (i = 0; i < active_nr; i++) {
 298                 struct string_list_item *item;
 299                 struct stage_data *e;
 300                 struct cache_entry *ce = active_cache[i];
 301                 if (!ce_stage(ce))
 302                         continue;
 303
 304                 item = string_list_lookup(ce->name, unmerged);
 305                 if (!item) {
 306                         item = string_list_insert(ce->name, unmerged);
 307                         item->util = xcalloc(1, sizeof(struct stage_data));
 308                 }
 309                 e = item->util;
 310                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 311                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 312         }
 313
 314         return unmerged;
 315 }
 316
 317 struct rename
 318 {
 319         struct diff_filepair *pair;
 320         struct stage_data *src_entry;
 321         struct stage_data *dst_entry;
 322         unsigned processed:1;
 323 };
 324
 325 /*
 326  * Get information of all renames which occurred between 'o_tree' and
 327  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 328  * 'b_tree') to be able to associate the correct cache entries with
 329  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 330  */
 331 static struct string_list *get_renames(struct merge_options *o,
 332                                        struct tree *tree,
 333                                        struct tree *o_tree,
 334                                        struct tree *a_tree,
 335                                        struct tree *b_tree,
 336                                        struct string_list *entries)
 337 {
 338         int i;
 339         struct string_list *renames;
 340         struct diff_options opts;
 341
 342         renames = xcalloc(1, sizeof(struct string_list));
 343         diff_setup(&opts);
 344         DIFF_OPT_SET(&opts, RECURSIVE);
 345         opts.detect_rename = DIFF_DETECT_RENAME;
 346         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 347                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 348                             500;
 349         opts.warn_on_too_large_rename = 1;
 350         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 351         if (diff_setup_done(&opts) < 0)
 352                 die("diff setup failed");
 353         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 354         diffcore_std(&opts);
 355         for (i = 0; i < diff_queued_diff.nr; ++i) {
 356                 struct string_list_item *item;
 357                 struct rename *re;
 358                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 359                 if (pair->status != 'R') {
 360                         diff_free_filepair(pair);
 361                         continue;
 362                 }
 363                 re = xmalloc(sizeof(*re));
 364                 re->processed = 0;
 365                 re->pair = pair;
 366                 item = string_list_lookup(re->pair->one->path, entries);
 367                 if (!item)
 368                         re->src_entry = insert_stage_data(re->pair->one->path,
 369                                         o_tree, a_tree, b_tree, entries);
 370                 else
 371                         re->src_entry = item->util;
 372
 373                 item = string_list_lookup(re->pair->two->path, entries);
 374                 if (!item)
 375                         re->dst_entry = insert_stage_data(re->pair->two->path,
 376                                         o_tree, a_tree, b_tree, entries);
 377                 else
 378                         re->dst_entry = item->util;
 379                 item = string_list_insert(pair->one->path, renames);
 380                 item->util = re;
 381         }
 382         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 383         diff_queued_diff.nr = 0;
 384         diff_flush(&opts);
 385         return renames;
 386 }
 387
 388 static int update_stages(const char *path, struct diff_filespec *o,
 389                          struct diff_filespec *a, struct diff_filespec *b,
 390                          int clear)
 391 {
 392         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 393         if (clear)
 394                 if (remove_file_from_cache(path))
 395                         return -1;
 396         if (o)
 397                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 398                         return -1;
 399         if (a)
 400                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 401                         return -1;
 402         if (b)
 403                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 404                         return -1;
 405         return 0;
 406 }
 407
 408 static int remove_file(struct merge_options *o, int clean,
 409                        const char *path, int no_wd)
 410 {
 411         int update_cache = o->call_depth || clean;
 412         int update_working_directory = !o->call_depth && !no_wd;
 413
 414         if (update_cache) {
 415                 if (remove_file_from_cache(path))
 416                         return -1;
 417         }
 418         if (update_working_directory) {
 419                 if (remove_path(path) && errno != ENOENT)
 420                         return -1;
 421         }
 422         return 0;
 423 }
 424
 425 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 426 {
 427         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 428         int suffix = 0;
 429         struct stat st;
 430         char *p = newpath + strlen(path);
 431         strcpy(newpath, path);
 432         *(p++) = '~';
 433         strcpy(p, branch);
 434         for (; *p; ++p)
 435                 if ('/' == *p)
 436                         *p = '_';
 437         while (string_list_has_string(&o->current_file_set, newpath) ||
 438                string_list_has_string(&o->current_directory_set, newpath) ||
 439                lstat(newpath, &st) == 0)
 440                 sprintf(p, "_%d", suffix++);
 441
 442         string_list_insert(newpath, &o->current_file_set);
 443         return newpath;
 444 }
 445
 446 static void flush_buffer(int fd, const char *buf, unsigned long size)
 447 {
 448         while (size > 0) {
 449                 long ret = write_in_full(fd, buf, size);
 450                 if (ret < 0) {
 451                         /* Ignore epipe */
 452                         if (errno == EPIPE)
 453                                 break;
 454                         die_errno("merge-recursive");
 455                 } else if (!ret) {
 456                         die("merge-recursive: disk full?");
 457                 }
 458                 size -= ret;
 459                 buf += ret;
 460         }
 461 }
 462
 463 static int would_lose_untracked(const char *path)
 464 {
 465         int pos = cache_name_pos(path, strlen(path));
 466
 467         if (pos < 0)
 468                 pos = -1 - pos;
 469         while (pos < active_nr &&
 470                !strcmp(path, active_cache[pos]->name)) {
 471                 /*
 472                  * If stage #0, it is definitely tracked.
 473                  * If it has stage #2 then it was tracked
 474                  * before this merge started.  All other
 475                  * cases the path was not tracked.
 476                  */
 477                 switch (ce_stage(active_cache[pos])) {
 478                 case 0:
 479                 case 2:
 480                         return 0;
 481                 }
 482                 pos++;
 483         }
 484         return file_exists(path);
 485 }
 486
 487 static int make_room_for_path(const char *path)
 488 {
 489         int status;
 490         const char *msg = "failed to create path '%s'%s";
 491
 492         status = safe_create_leading_directories_const(path);
 493         if (status) {
 494                 if (status == -3) {
 495                         /* something else exists */
 496                         error(msg, path, ": perhaps a D/F conflict?");
 497                         return -1;
 498                 }
 499                 die(msg, path, "");
 500         }
 501
 502         /*
 503          * Do not unlink a file in the work tree if we are not
 504          * tracking it.
 505          */
 506         if (would_lose_untracked(path))
 507                 return error("refusing to lose untracked file at '%s'",
 508                              path);
 509
 510         /* Successful unlink is good.. */
 511         if (!unlink(path))
 512                 return 0;
 513         /* .. and so is no existing file */
 514         if (errno == ENOENT)
 515                 return 0;
 516         /* .. but not some other error (who really cares what?) */
 517         return error(msg, path, ": perhaps a D/F conflict?");
 518 }
 519
 520 static void update_file_flags(struct merge_options *o,
 521                               const unsigned char *sha,
 522                               unsigned mode,
 523                               const char *path,
 524                               int update_cache,
 525                               int update_wd)
 526 {
 527         if (o->call_depth)
 528                 update_wd = 0;
 529
 530         if (update_wd) {
 531                 enum object_type type;
 532                 void *buf;
 533                 unsigned long size;
 534
 535                 if (S_ISGITLINK(mode))
 536                         /*
 537                          * We may later decide to recursively descend into
 538                          * the submodule directory and update its index
 539                          * and/or work tree, but we do not do that now.
 540                          */
 541                         goto update_index;
 542
 543                 buf = read_sha1_file(sha, &type, &size);
 544                 if (!buf)
 545                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 546                 if (type != OBJ_BLOB)
 547                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 548                 if (S_ISREG(mode)) {
 549                         struct strbuf strbuf = STRBUF_INIT;
 550                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 551                                 free(buf);
 552                                 size = strbuf.len;
 553                                 buf = strbuf_detach(&strbuf, NULL);
 554                         }
 555                 }
 556
 557                 if (make_room_for_path(path) < 0) {
 558                         update_wd = 0;
 559                         free(buf);
 560                         goto update_index;
 561                 }
 562                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 563                         int fd;
 564                         if (mode & 0100)
 565                                 mode = 0777;
 566                         else
 567                                 mode = 0666;
 568                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 569                         if (fd < 0)
 570                                 die_errno("failed to open '%s'", path);
 571                         flush_buffer(fd, buf, size);
 572                         close(fd);
 573                 } else if (S_ISLNK(mode)) {
 574                         char *lnk = xmemdupz(buf, size);
 575                         safe_create_leading_directories_const(path);
 576                         unlink(path);
 577                         if (symlink(lnk, path))
 578                                 die_errno("failed to symlink '%s'", path);
 579                         free(lnk);
 580                 } else
 581                         die("do not know what to do with %06o %s '%s'",
 582                             mode, sha1_to_hex(sha), path);
 583                 free(buf);
 584         }
 585  update_index:
 586         if (update_cache)
 587                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 588 }
 589
 590 static void update_file(struct merge_options *o,
 591                         int clean,
 592                         const unsigned char *sha,
 593                         unsigned mode,
 594                         const char *path)
 595 {
 596         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 597 }
 598
 599 /* Low level file merging, update and removal */
 600
 601 struct merge_file_info
 602 {
 603         unsigned char sha[20];
 604         unsigned mode;
 605         unsigned clean:1,
 606                  merge:1;
 607 };
 608
 609 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 610 {
 611         unsigned long size;
 612         enum object_type type;
 613
 614         if (!hashcmp(sha1, null_sha1)) {
 615                 mm->ptr = xstrdup("");
 616                 mm->size = 0;
 617                 return;
 618         }
 619
 620         mm->ptr = read_sha1_file(sha1, &type, &size);
 621         if (!mm->ptr || type != OBJ_BLOB)
 622                 die("unable to read blob object %s", sha1_to_hex(sha1));
 623         mm->size = size;
 624 }
 625
 626 static int merge_3way(struct merge_options *o,
 627                       mmbuffer_t *result_buf,
 628                       struct diff_filespec *one,
 629                       struct diff_filespec *a,
 630                       struct diff_filespec *b,
 631                       const char *branch1,
 632                       const char *branch2)
 633 {
 634         mmfile_t orig, src1, src2;
 635         char *name1, *name2;
 636         int merge_status;
 637
 638         if (strcmp(a->path, b->path)) {
 639                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 640                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 641         } else {
 642                 name1 = xstrdup(mkpath("%s", branch1));
 643                 name2 = xstrdup(mkpath("%s", branch2));
 644         }
 645
 646         fill_mm(one->sha1, &orig);
 647         fill_mm(a->sha1, &src1);
 648         fill_mm(b->sha1, &src2);
 649
 650         merge_status = ll_merge(result_buf, a->path, &orig,
 651                                 &src1, name1, &src2, name2,
 652                                 o->call_depth);
 653
 654         free(name1);
 655         free(name2);
 656         free(orig.ptr);
 657         free(src1.ptr);
 658         free(src2.ptr);
 659         return merge_status;
 660 }
 661
 662 static struct merge_file_info merge_file(struct merge_options *o,
 663                                          struct diff_filespec *one,
 664                                          struct diff_filespec *a,
 665                                          struct diff_filespec *b,
 666                                          const char *branch1,
 667                                          const char *branch2)
 668 {
 669         struct merge_file_info result;
 670         result.merge = 0;
 671         result.clean = 1;
 672
 673         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 674                 result.clean = 0;
 675                 if (S_ISREG(a->mode)) {
 676                         result.mode = a->mode;
 677                         hashcpy(result.sha, a->sha1);
 678                 } else {
 679                         result.mode = b->mode;
 680                         hashcpy(result.sha, b->sha1);
 681                 }
 682         } else {
 683                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 684                         result.merge = 1;
 685
 686                 /*
 687                  * Merge modes
 688                  */
 689                 if (a->mode == b->mode || a->mode == one->mode)
 690                         result.mode = b->mode;
 691                 else {
 692                         result.mode = a->mode;
 693                         if (b->mode != one->mode) {
 694                                 result.clean = 0;
 695                                 result.merge = 1;
 696                         }
 697                 }
 698
 699                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 700                         hashcpy(result.sha, b->sha1);
 701                 else if (sha_eq(b->sha1, one->sha1))
 702                         hashcpy(result.sha, a->sha1);
 703                 else if (S_ISREG(a->mode)) {
 704                         mmbuffer_t result_buf;
 705                         int merge_status;
 706
 707                         merge_status = merge_3way(o, &result_buf, one, a, b,
 708                                                   branch1, branch2);
 709
 710                         if ((merge_status < 0) || !result_buf.ptr)
 711                                 die("Failed to execute internal merge");
 712
 713                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 714                                             blob_type, result.sha))
 715                                 die("Unable to add %s to database",
 716                                     a->path);
 717
 718                         free(result_buf.ptr);
 719                         result.clean = (merge_status == 0);
 720                 } else if (S_ISGITLINK(a->mode)) {
 721                         result.clean = 0;
 722                         hashcpy(result.sha, a->sha1);
 723                 } else if (S_ISLNK(a->mode)) {
 724                         hashcpy(result.sha, a->sha1);
 725
 726                         if (!sha_eq(a->sha1, b->sha1))
 727                                 result.clean = 0;
 728                 } else {
 729                         die("unsupported object type in the tree");
 730                 }
 731         }
 732
 733         return result;
 734 }
 735
 736 static void conflict_rename_rename(struct merge_options *o,
 737                                    struct rename *ren1,
 738                                    const char *branch1,
 739                                    struct rename *ren2,
 740                                    const char *branch2)
 741 {
 742         char *del[2];
 743         int delp = 0;
 744         const char *ren1_dst = ren1->pair->two->path;
 745         const char *ren2_dst = ren2->pair->two->path;
 746         const char *dst_name1 = ren1_dst;
 747         const char *dst_name2 = ren2_dst;
 748         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 749                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 750                 output(o, 1, "%s is a directory in %s adding as %s instead",
 751                        ren1_dst, branch2, dst_name1);
 752                 remove_file(o, 0, ren1_dst, 0);
 753         }
 754         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 755                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 756                 output(o, 1, "%s is a directory in %s adding as %s instead",
 757                        ren2_dst, branch1, dst_name2);
 758                 remove_file(o, 0, ren2_dst, 0);
 759         }
 760         if (o->call_depth) {
 761                 remove_file_from_cache(dst_name1);
 762                 remove_file_from_cache(dst_name2);
 763                 /*
 764                  * Uncomment to leave the conflicting names in the resulting tree
 765                  *
 766                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 767                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 768                  */
 769         } else {
 770                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 771                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 772         }
 773         while (delp--)
 774                 free(del[delp]);
 775 }
 776
 777 static void conflict_rename_dir(struct merge_options *o,
 778                                 struct rename *ren1,
 779                                 const char *branch1)
 780 {
 781         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 782         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 783         remove_file(o, 0, ren1->pair->two->path, 0);
 784         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 785         free(new_path);
 786 }
 787
 788 static void conflict_rename_rename_2(struct merge_options *o,
 789                                      struct rename *ren1,
 790                                      const char *branch1,
 791                                      struct rename *ren2,
 792                                      const char *branch2)
 793 {
 794         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 795         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 796         output(o, 1, "Renaming %s to %s and %s to %s instead",
 797                ren1->pair->one->path, new_path1,
 798                ren2->pair->one->path, new_path2);
 799         remove_file(o, 0, ren1->pair->two->path, 0);
 800         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 801         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 802         free(new_path2);
 803         free(new_path1);
 804 }
 805
 806 static int process_renames(struct merge_options *o,
 807                            struct string_list *a_renames,
 808                            struct string_list *b_renames)
 809 {
 810         int clean_merge = 1, i, j;
 811         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 812         const struct rename *sre;
 813
 814         for (i = 0; i < a_renames->nr; i++) {
 815                 sre = a_renames->items[i].util;
 816                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 817                         = sre->dst_entry;
 818         }
 819         for (i = 0; i < b_renames->nr; i++) {
 820                 sre = b_renames->items[i].util;
 821                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 822                         = sre->dst_entry;
 823         }
 824
 825         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 826                 char *src;
 827                 struct string_list *renames1, *renames2Dst;
 828                 struct rename *ren1 = NULL, *ren2 = NULL;
 829                 const char *branch1, *branch2;
 830                 const char *ren1_src, *ren1_dst;
 831
 832                 if (i >= a_renames->nr) {
 833                         ren2 = b_renames->items[j++].util;
 834                 } else if (j >= b_renames->nr) {
 835                         ren1 = a_renames->items[i++].util;
 836                 } else {
 837                         int compare = strcmp(a_renames->items[i].string,
 838                                              b_renames->items[j].string);
 839                         if (compare <= 0)
 840                                 ren1 = a_renames->items[i++].util;
 841                         if (compare >= 0)
 842                                 ren2 = b_renames->items[j++].util;
 843                 }
 844
 845                 /* TODO: refactor, so that 1/2 are not needed */
 846                 if (ren1) {
 847                         renames1 = a_renames;
 848                         renames2Dst = &b_by_dst;
 849                         branch1 = o->branch1;
 850                         branch2 = o->branch2;
 851                 } else {
 852                         struct rename *tmp;
 853                         renames1 = b_renames;
 854                         renames2Dst = &a_by_dst;
 855                         branch1 = o->branch2;
 856                         branch2 = o->branch1;
 857                         tmp = ren2;
 858                         ren2 = ren1;
 859                         ren1 = tmp;
 860                 }
 861                 src = ren1->pair->one->path;
 862
 863                 ren1->dst_entry->processed = 1;
 864                 ren1->src_entry->processed = 1;
 865
 866                 if (ren1->processed)
 867                         continue;
 868                 ren1->processed = 1;
 869
 870                 ren1_src = ren1->pair->one->path;
 871                 ren1_dst = ren1->pair->two->path;
 872
 873                 if (ren2) {
 874                         const char *ren2_src = ren2->pair->one->path;
 875                         const char *ren2_dst = ren2->pair->two->path;
 876                         /* Renamed in 1 and renamed in 2 */
 877                         if (strcmp(ren1_src, ren2_src) != 0)
 878                                 die("ren1.src != ren2.src");
 879                         ren2->dst_entry->processed = 1;
 880                         ren2->processed = 1;
 881                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 882                                 clean_merge = 0;
 883                                 output(o, 1, "CONFLICT (rename/rename): "
 884                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 885                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 886                                        src, ren1_dst, branch1,
 887                                        src, ren2_dst, branch2,
 888                                        o->call_depth ? " (left unresolved)": "");
 889                                 if (o->call_depth) {
 890                                         remove_file_from_cache(src);
 891                                         update_file(o, 0, ren1->pair->one->sha1,
 892                                                     ren1->pair->one->mode, src);
 893                                 }
 894                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 895                         } else {
 896                                 struct merge_file_info mfi;
 897                                 remove_file(o, 1, ren1_src, 1);
 898                                 mfi = merge_file(o,
 899                                                  ren1->pair->one,
 900                                                  ren1->pair->two,
 901                                                  ren2->pair->two,
 902                                                  branch1,
 903                                                  branch2);
 904                                 if (mfi.merge || !mfi.clean)
 905                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 906
 907                                 if (mfi.merge)
 908                                         output(o, 2, "Auto-merging %s", ren1_dst);
 909
 910                                 if (!mfi.clean) {
 911                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 912                                                ren1_dst);
 913                                         clean_merge = 0;
 914
 915                                         if (!o->call_depth)
 916                                                 update_stages(ren1_dst,
 917                                                               ren1->pair->one,
 918                                                               ren1->pair->two,
 919                                                               ren2->pair->two,
 920                                                               1 /* clear */);
 921                                 }
 922                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 923                         }
 924                 } else {
 925                         /* Renamed in 1, maybe changed in 2 */
 926                         struct string_list_item *item;
 927                         /* we only use sha1 and mode of these */
 928                         struct diff_filespec src_other, dst_other;
 929                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 930
 931                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 932
 933                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 934                         src_other.mode = ren1->src_entry->stages[stage].mode;
 935                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 936                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 937
 938                         try_merge = 0;
 939
 940                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 941                                 clean_merge = 0;
 942                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 943                                        " directory %s added in %s",
 944                                        ren1_src, ren1_dst, branch1,
 945                                        ren1_dst, branch2);
 946                                 conflict_rename_dir(o, ren1, branch1);
 947                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 948                                 clean_merge = 0;
 949                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 950                                        "and deleted in %s",
 951                                        ren1_src, ren1_dst, branch1,
 952                                        branch2);
 953                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 954                                 if (!o->call_depth)
 955                                         update_stages(ren1_dst, NULL,
 956                                                         branch1 == o->branch1 ?
 957                                                         ren1->pair->two : NULL,
 958                                                         branch1 == o->branch1 ?
 959                                                         NULL : ren1->pair->two, 1);
 960                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 961                                 const char *new_path;
 962                                 clean_merge = 0;
 963                                 try_merge = 1;
 964                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 965                                        "%s added in %s",
 966                                        ren1_src, ren1_dst, branch1,
 967                                        ren1_dst, branch2);
 968                                 if (o->call_depth) {
 969                                         struct merge_file_info mfi;
 970                                         struct diff_filespec one, a, b;
 971
 972                                         one.path = a.path = b.path =
 973                                                 (char *)ren1_dst;
 974                                         hashcpy(one.sha1, null_sha1);
 975                                         one.mode = 0;
 976                                         hashcpy(a.sha1, ren1->pair->two->sha1);
 977                                         a.mode = ren1->pair->two->mode;
 978                                         hashcpy(b.sha1, dst_other.sha1);
 979                                         b.mode = dst_other.mode;
 980                                         mfi = merge_file(o, &one, &a, &b,
 981                                                          branch1,
 982                                                          branch2);
 983                                         output(o, 1, "Adding merged %s", ren1_dst);
 984                                         update_file(o, 0,
 985                                                     mfi.sha,
 986                                                     mfi.mode,
 987                                                     ren1_dst);
 988                                 } else {
 989                                         new_path = unique_path(o, ren1_dst, branch2);
 990                                         output(o, 1, "Adding as %s instead", new_path);
 991                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 992                                 }
 993                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 994                                 ren2 = item->util;
 995                                 clean_merge = 0;
 996                                 ren2->processed = 1;
 997                                 output(o, 1, "CONFLICT (rename/rename): "
 998                                        "Rename %s->%s in %s. "
 999                                        "Rename %s->%s in %s",
1000                                        ren1_src, ren1_dst, branch1,
1001                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1002                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1003                         } else
1004                                 try_merge = 1;
1005
1006                         if (try_merge) {
1007                                 struct diff_filespec *one, *a, *b;
1008                                 struct merge_file_info mfi;
1009                                 src_other.path = (char *)ren1_src;
1010
1011                                 one = ren1->pair->one;
1012                                 if (a_renames == renames1) {
1013                                         a = ren1->pair->two;
1014                                         b = &src_other;
1015                                 } else {
1016                                         b = ren1->pair->two;
1017                                         a = &src_other;
1018                                 }
1019                                 mfi = merge_file(o, one, a, b,
1020                                                 o->branch1, o->branch2);
1021
1022                                 if (mfi.clean &&
1023                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1024                                     mfi.mode == ren1->pair->two->mode)
1025                                         /*
1026                                          * This messaged is part of
1027                                          * t6022 test. If you change
1028                                          * it update the test too.
1029                                          */
1030                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1031                                 else {
1032                                         if (mfi.merge || !mfi.clean)
1033                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1034                                         if (mfi.merge)
1035                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1036                                         if (!mfi.clean) {
1037                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1038                                                        ren1_dst);
1039                                                 clean_merge = 0;
1040
1041                                                 if (!o->call_depth)
1042                                                         update_stages(ren1_dst,
1043                                                                       one, a, b, 1);
1044                                         }
1045                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1046                                 }
1047                         }
1048                 }
1049         }
1050         string_list_clear(&a_by_dst, 0);
1051         string_list_clear(&b_by_dst, 0);
1052
1053         return clean_merge;
1054 }
1055
1056 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1057 {
1058         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1059 }
1060
1061 /* Per entry merge function */
1062 static int process_entry(struct merge_options *o,
1063                          const char *path, struct stage_data *entry)
1064 {
1065         /*
1066         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1067         print_index_entry("\tpath: ", entry);
1068         */
1069         int clean_merge = 1;
1070         unsigned o_mode = entry->stages[1].mode;
1071         unsigned a_mode = entry->stages[2].mode;
1072         unsigned b_mode = entry->stages[3].mode;
1073         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1074         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1075         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1076
1077         if (o_sha && (!a_sha || !b_sha)) {
1078                 /* Case A: Deleted in one */
1079                 if ((!a_sha && !b_sha) ||
1080                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1081                     (!a_sha && sha_eq(b_sha, o_sha))) {
1082                         /* Deleted in both or deleted in one and
1083                          * unchanged in the other */
1084                         if (a_sha)
1085                                 output(o, 2, "Removing %s", path);
1086                         /* do not touch working file if it did not exist */
1087                         remove_file(o, 1, path, !a_sha);
1088                 } else {
1089                         /* Deleted in one and changed in the other */
1090                         clean_merge = 0;
1091                         if (!a_sha) {
1092                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1093                                        "and modified in %s. Version %s of %s left in tree.",
1094                                        path, o->branch1,
1095                                        o->branch2, o->branch2, path);
1096                                 update_file(o, 0, b_sha, b_mode, path);
1097                         } else {
1098                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1099                                        "and modified in %s. Version %s of %s left in tree.",
1100                                        path, o->branch2,
1101                                        o->branch1, o->branch1, path);
1102                                 update_file(o, 0, a_sha, a_mode, path);
1103                         }
1104                 }
1105
1106         } else if ((!o_sha && a_sha && !b_sha) ||
1107                    (!o_sha && !a_sha && b_sha)) {
1108                 /* Case B: Added in one. */
1109                 const char *add_branch;
1110                 const char *other_branch;
1111                 unsigned mode;
1112                 const unsigned char *sha;
1113                 const char *conf;
1114
1115                 if (a_sha) {
1116                         add_branch = o->branch1;
1117                         other_branch = o->branch2;
1118                         mode = a_mode;
1119                         sha = a_sha;
1120                         conf = "file/directory";
1121                 } else {
1122                         add_branch = o->branch2;
1123                         other_branch = o->branch1;
1124                         mode = b_mode;
1125                         sha = b_sha;
1126                         conf = "directory/file";
1127                 }
1128                 if (string_list_has_string(&o->current_directory_set, path)) {
1129                         const char *new_path = unique_path(o, path, add_branch);
1130                         clean_merge = 0;
1131                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1132                                "Adding %s as %s",
1133                                conf, path, other_branch, path, new_path);
1134                         remove_file(o, 0, path, 0);
1135                         update_file(o, 0, sha, mode, new_path);
1136                 } else {
1137                         output(o, 2, "Adding %s", path);
1138                         update_file(o, 1, sha, mode, path);
1139                 }
1140         } else if (a_sha && b_sha) {
1141                 /* Case C: Added in both (check for same permissions) and */
1142                 /* case D: Modified in both, but differently. */
1143                 const char *reason = "content";
1144                 struct merge_file_info mfi;
1145                 struct diff_filespec one, a, b;
1146
1147                 if (!o_sha) {
1148                         reason = "add/add";
1149                         o_sha = (unsigned char *)null_sha1;
1150                 }
1151                 output(o, 2, "Auto-merging %s", path);
1152                 one.path = a.path = b.path = (char *)path;
1153                 hashcpy(one.sha1, o_sha);
1154                 one.mode = o_mode;
1155                 hashcpy(a.sha1, a_sha);
1156                 a.mode = a_mode;
1157                 hashcpy(b.sha1, b_sha);
1158                 b.mode = b_mode;
1159
1160                 mfi = merge_file(o, &one, &a, &b,
1161                                  o->branch1, o->branch2);
1162
1163                 clean_merge = mfi.clean;
1164                 if (!mfi.clean) {
1165                         if (S_ISGITLINK(mfi.mode))
1166                                 reason = "submodule";
1167                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1168                                         reason, path);
1169                 }
1170                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1171         } else if (!o_sha && !a_sha && !b_sha) {
1172                 /*
1173                  * this entry was deleted altogether. a_mode == 0 means
1174                  * we had that path and want to actively remove it.
1175                  */
1176                 remove_file(o, 1, path, !a_mode);
1177         } else
1178                 die("Fatal merge failure, shouldn't happen.");
1179
1180         return clean_merge;
1181 }
1182
1183 int merge_trees(struct merge_options *o,
1184                 struct tree *head,
1185                 struct tree *merge,
1186                 struct tree *common,
1187                 struct tree **result)
1188 {
1189         int code, clean;
1190
1191         if (o->subtree_merge) {
1192                 merge = shift_tree_object(head, merge);
1193                 common = shift_tree_object(head, common);
1194         }
1195
1196         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1197                 output(o, 0, "Already uptodate!");
1198                 *result = head;
1199                 return 1;
1200         }
1201
1202         code = git_merge_trees(o->call_depth, common, head, merge);
1203
1204         if (code != 0) {
1205                 if (show(o, 4) || o->call_depth)
1206                         die("merging of trees %s and %s failed",
1207                             sha1_to_hex(head->object.sha1),
1208                             sha1_to_hex(merge->object.sha1));
1209                 else
1210                         exit(128);
1211         }
1212
1213         if (unmerged_cache()) {
1214                 struct string_list *entries, *re_head, *re_merge;
1215                 int i;
1216                 string_list_clear(&o->current_file_set, 1);
1217                 string_list_clear(&o->current_directory_set, 1);
1218                 get_files_dirs(o, head);
1219                 get_files_dirs(o, merge);
1220
1221                 entries = get_unmerged();
1222                 re_head  = get_renames(o, head, common, head, merge, entries);
1223                 re_merge = get_renames(o, merge, common, head, merge, entries);
1224                 clean = process_renames(o, re_head, re_merge);
1225                 for (i = 0; i < entries->nr; i++) {
1226                         const char *path = entries->items[i].string;
1227                         struct stage_data *e = entries->items[i].util;
1228                         if (!e->processed
1229                                 && !process_entry(o, path, e))
1230                                 clean = 0;
1231                 }
1232
1233                 string_list_clear(re_merge, 0);
1234                 string_list_clear(re_head, 0);
1235                 string_list_clear(entries, 1);
1236
1237         }
1238         else
1239                 clean = 1;
1240
1241         if (o->call_depth)
1242                 *result = write_tree_from_memory(o);
1243
1244         return clean;
1245 }
1246
1247 static struct commit_list *reverse_commit_list(struct commit_list *list)
1248 {
1249         struct commit_list *next = NULL, *current, *backup;
1250         for (current = list; current; current = backup) {
1251                 backup = current->next;
1252                 current->next = next;
1253                 next = current;
1254         }
1255         return next;
1256 }
1257
1258 /*
1259  * Merge the commits h1 and h2, return the resulting virtual
1260  * commit object and a flag indicating the cleanness of the merge.
1261  */
1262 int merge_recursive(struct merge_options *o,
1263                     struct commit *h1,
1264                     struct commit *h2,
1265                     struct commit_list *ca,
1266                     struct commit **result)
1267 {
1268         struct commit_list *iter;
1269         struct commit *merged_common_ancestors;
1270         struct tree *mrtree = mrtree;
1271         int clean;
1272
1273         if (show(o, 4)) {
1274                 output(o, 4, "Merging:");
1275                 output_commit_title(o, h1);
1276                 output_commit_title(o, h2);
1277         }
1278
1279         if (!ca) {
1280                 ca = get_merge_bases(h1, h2, 1);
1281                 ca = reverse_commit_list(ca);
1282         }
1283
1284         if (show(o, 5)) {
1285                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1286                 for (iter = ca; iter; iter = iter->next)
1287                         output_commit_title(o, iter->item);
1288         }
1289
1290         merged_common_ancestors = pop_commit(&ca);
1291         if (merged_common_ancestors == NULL) {
1292                 /* if there is no common ancestor, make an empty tree */
1293                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1294
1295                 tree->object.parsed = 1;
1296                 tree->object.type = OBJ_TREE;
1297                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1298                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1299         }
1300
1301         for (iter = ca; iter; iter = iter->next) {
1302                 const char *saved_b1, *saved_b2;
1303                 o->call_depth++;
1304                 /*
1305                  * When the merge fails, the result contains files
1306                  * with conflict markers. The cleanness flag is
1307                  * ignored, it was never actually used, as result of
1308                  * merge_trees has always overwritten it: the committed
1309                  * "conflicts" were already resolved.
1310                  */
1311                 discard_cache();
1312                 saved_b1 = o->branch1;
1313                 saved_b2 = o->branch2;
1314                 o->branch1 = "Temporary merge branch 1";
1315                 o->branch2 = "Temporary merge branch 2";
1316                 merge_recursive(o, merged_common_ancestors, iter->item,
1317                                 NULL, &merged_common_ancestors);
1318                 o->branch1 = saved_b1;
1319                 o->branch2 = saved_b2;
1320                 o->call_depth--;
1321
1322                 if (!merged_common_ancestors)
1323                         die("merge returned no commit");
1324         }
1325
1326         discard_cache();
1327         if (!o->call_depth)
1328                 read_cache();
1329
1330         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1331                             &mrtree);
1332
1333         if (o->call_depth) {
1334                 *result = make_virtual_commit(mrtree, "merged tree");
1335                 commit_list_insert(h1, &(*result)->parents);
1336                 commit_list_insert(h2, &(*result)->parents->next);
1337         }
1338         flush_output(o);
1339         return clean;
1340 }
1341
1342 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1343 {
1344         struct object *object;
1345
1346         object = deref_tag(parse_object(sha1), name, strlen(name));
1347         if (!object)
1348                 return NULL;
1349         if (object->type == OBJ_TREE)
1350                 return make_virtual_commit((struct tree*)object, name);
1351         if (object->type != OBJ_COMMIT)
1352                 return NULL;
1353         if (parse_commit((struct commit *)object))
1354                 return NULL;
1355         return (struct commit *)object;
1356 }
1357
1358 int merge_recursive_generic(struct merge_options *o,
1359                             const unsigned char *head,
1360                             const unsigned char *merge,
1361                             int num_base_list,
1362                             const unsigned char **base_list,
1363                             struct commit **result)
1364 {
1365         int clean, index_fd;
1366         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1367         struct commit *head_commit = get_ref(head, o->branch1);
1368         struct commit *next_commit = get_ref(merge, o->branch2);
1369         struct commit_list *ca = NULL;
1370
1371         if (base_list) {
1372                 int i;
1373                 for (i = 0; i < num_base_list; ++i) {
1374                         struct commit *base;
1375                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1376                                 return error("Could not parse object '%s'",
1377                                         sha1_to_hex(base_list[i]));
1378                         commit_list_insert(base, &ca);
1379                 }
1380         }
1381
1382         index_fd = hold_locked_index(lock, 1);
1383         clean = merge_recursive(o, head_commit, next_commit, ca,
1384                         result);
1385         if (active_cache_changed &&
1386                         (write_cache(index_fd, active_cache, active_nr) ||
1387                          commit_locked_index(lock)))
1388                 return error("Unable to write index.");
1389
1390         return clean ? 0 : 1;
1391 }
1392
1393 static int merge_recursive_config(const char *var, const char *value, void *cb)
1394 {
1395         struct merge_options *o = cb;
1396         if (!strcasecmp(var, "merge.verbosity")) {
1397                 o->verbosity = git_config_int(var, value);
1398                 return 0;
1399         }
1400         if (!strcasecmp(var, "diff.renamelimit")) {
1401                 o->diff_rename_limit = git_config_int(var, value);
1402                 return 0;
1403         }
1404         if (!strcasecmp(var, "merge.renamelimit")) {
1405                 o->merge_rename_limit = git_config_int(var, value);
1406                 return 0;
1407         }
1408         return git_xmerge_config(var, value, cb);
1409 }
1410
1411 void init_merge_options(struct merge_options *o)
1412 {
1413         memset(o, 0, sizeof(struct merge_options));
1414         o->verbosity = 2;
1415         o->buffer_output = 1;
1416         o->diff_rename_limit = -1;
1417         o->merge_rename_limit = -1;
1418         git_config(merge_recursive_config, o);
1419         if (getenv("GIT_MERGE_VERBOSITY"))
1420                 o->verbosity =
1421                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1422         if (o->verbosity >= 5)
1423                 o->buffer_output = 0;
1424         strbuf_init(&o->obuf, 0);
1425         memset(&o->current_file_set, 0, sizeof(struct string_list));
1426         o->current_file_set.strdup_strings = 1;
1427         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1428         o->current_directory_set.strdup_strings = 1;
1429 }