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