merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "builtin.h"
  11 #include "tree-walk.h"
  12 #include "diff.h"
  13 #include "diffcore.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "string-list.h"
  17 #include "xdiff-interface.h"
  18 #include "ll-merge.h"
  19 #include "interpolate.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22 #include "dir.h"
  23
  24 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  25 {
  26         unsigned char shifted[20];
  27
  28         /*
  29          * NEEDSWORK: this limits the recursion depth to hardcoded
  30          * value '2' to avoid excessive overhead.
  31          */
  32         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  33         if (!hashcmp(two->object.sha1, shifted))
  34                 return two;
  35         return lookup_tree(shifted);
  36 }
  37
  38 /*
  39  * A virtual commit has (const char *)commit->util set to the name.
  40  */
  41
  42 struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  43 {
  44         struct commit *commit = xcalloc(1, sizeof(struct commit));
  45         commit->tree = tree;
  46         commit->util = (void*)comment;
  47         /* avoid warnings */
  48         commit->object.parsed = 1;
  49         return commit;
  50 }
  51
  52 /*
  53  * Since we use get_tree_entry(), which does not put the read object into
  54  * the object pool, we cannot rely on a == b.
  55  */
  56 static int sha_eq(const unsigned char *a, const unsigned char *b)
  57 {
  58         if (!a && !b)
  59                 return 2;
  60         return a && b && hashcmp(a, b) == 0;
  61 }
  62
  63 /*
  64  * Since we want to write the index eventually, we cannot reuse the index
  65  * for these (temporary) data.
  66  */
  67 struct stage_data
  68 {
  69         struct
  70         {
  71                 unsigned mode;
  72                 unsigned char sha[20];
  73         } stages[4];
  74         unsigned processed:1;
  75 };
  76
  77 static int show(struct merge_options *o, int v)
  78 {
  79         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  80 }
  81
  82 static void flush_output(struct merge_options *o)
  83 {
  84         if (o->obuf.len) {
  85                 fputs(o->obuf.buf, stdout);
  86                 strbuf_reset(&o->obuf);
  87         }
  88 }
  89
  90 static void output(struct merge_options *o, int v, const char *fmt, ...)
  91 {
  92         int len;
  93         va_list ap;
  94
  95         if (!show(o, v))
  96                 return;
  97
  98         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
  99         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 100         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 101
 102         va_start(ap, fmt);
 103         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 104         va_end(ap);
 105
 106         if (len < 0)
 107                 len = 0;
 108         if (len >= strbuf_avail(&o->obuf)) {
 109                 strbuf_grow(&o->obuf, len + 2);
 110                 va_start(ap, fmt);
 111                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 112                 va_end(ap);
 113                 if (len >= strbuf_avail(&o->obuf)) {
 114                         die("this should not happen, your snprintf is broken");
 115                 }
 116         }
 117         strbuf_setlen(&o->obuf, o->obuf.len + len);
 118         strbuf_add(&o->obuf, "\n", 1);
 119         if (!o->buffer_output)
 120                 flush_output(o);
 121 }
 122
 123 static void output_commit_title(struct merge_options *o, struct commit *commit)
 124 {
 125         int i;
 126         flush_output(o);
 127         for (i = o->call_depth; i--;)
 128                 fputs("  ", stdout);
 129         if (commit->util)
 130                 printf("virtual %s\n", (char *)commit->util);
 131         else {
 132                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 133                 if (parse_commit(commit) != 0)
 134                         printf("(bad commit)\n");
 135                 else {
 136                         const char *s;
 137                         int len;
 138                         for (s = commit->buffer; *s; s++)
 139                                 if (*s == '\n' && s[1] == '\n') {
 140                                         s += 2;
 141                                         break;
 142                                 }
 143                         for (len = 0; s[len] && '\n' != s[len]; len++)
 144                                 ; /* do nothing */
 145                         printf("%.*s\n", len, s);
 146                 }
 147         }
 148 }
 149
 150 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 151                 const char *path, int stage, int refresh, int options)
 152 {
 153         struct cache_entry *ce;
 154         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 155         if (!ce)
 156                 return error("addinfo_cache failed for path '%s'", path);
 157         return add_cache_entry(ce, options);
 158 }
 159
 160 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 161 {
 162         parse_tree(tree);
 163         init_tree_desc(desc, tree->buffer, tree->size);
 164 }
 165
 166 static int git_merge_trees(int index_only,
 167                            struct tree *common,
 168                            struct tree *head,
 169                            struct tree *merge)
 170 {
 171         int rc;
 172         struct tree_desc t[3];
 173         struct unpack_trees_options opts;
 174
 175         memset(&opts, 0, sizeof(opts));
 176         if (index_only)
 177                 opts.index_only = 1;
 178         else
 179                 opts.update = 1;
 180         opts.merge = 1;
 181         opts.head_idx = 2;
 182         opts.fn = threeway_merge;
 183         opts.src_index = &the_index;
 184         opts.dst_index = &the_index;
 185
 186         init_tree_desc_from_tree(t+0, common);
 187         init_tree_desc_from_tree(t+1, head);
 188         init_tree_desc_from_tree(t+2, merge);
 189
 190         rc = unpack_trees(3, t, &opts);
 191         cache_tree_free(&active_cache_tree);
 192         return rc;
 193 }
 194
 195 struct tree *write_tree_from_memory(struct merge_options *o)
 196 {
 197         struct tree *result = NULL;
 198
 199         if (unmerged_cache()) {
 200                 int i;
 201                 output(o, 0, "There are unmerged index entries:");
 202                 for (i = 0; i < active_nr; i++) {
 203                         struct cache_entry *ce = active_cache[i];
 204                         if (ce_stage(ce))
 205                                 output(o, 0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 206                 }
 207                 return NULL;
 208         }
 209
 210         if (!active_cache_tree)
 211                 active_cache_tree = cache_tree();
 212
 213         if (!cache_tree_fully_valid(active_cache_tree) &&
 214             cache_tree_update(active_cache_tree,
 215                               active_cache, active_nr, 0, 0) < 0)
 216                 die("error building trees");
 217
 218         result = lookup_tree(active_cache_tree->sha1);
 219
 220         return result;
 221 }
 222
 223 static int save_files_dirs(const unsigned char *sha1,
 224                 const char *base, int baselen, const char *path,
 225                 unsigned int mode, int stage, void *context)
 226 {
 227         int len = strlen(path);
 228         char *newpath = xmalloc(baselen + len + 1);
 229         struct merge_options *o = context;
 230
 231         memcpy(newpath, base, baselen);
 232         memcpy(newpath + baselen, path, len);
 233         newpath[baselen + len] = '\0';
 234
 235         if (S_ISDIR(mode))
 236                 string_list_insert(newpath, &o->current_directory_set);
 237         else
 238                 string_list_insert(newpath, &o->current_file_set);
 239         free(newpath);
 240
 241         return READ_TREE_RECURSIVE;
 242 }
 243
 244 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 245 {
 246         int n;
 247         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 248                 return 0;
 249         n = o->current_file_set.nr + o->current_directory_set.nr;
 250         return n;
 251 }
 252
 253 /*
 254  * Returns an index_entry instance which doesn't have to correspond to
 255  * a real cache entry in Git's index.
 256  */
 257 static struct stage_data *insert_stage_data(const char *path,
 258                 struct tree *o, struct tree *a, struct tree *b,
 259                 struct string_list *entries)
 260 {
 261         struct string_list_item *item;
 262         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 263         get_tree_entry(o->object.sha1, path,
 264                         e->stages[1].sha, &e->stages[1].mode);
 265         get_tree_entry(a->object.sha1, path,
 266                         e->stages[2].sha, &e->stages[2].mode);
 267         get_tree_entry(b->object.sha1, path,
 268                         e->stages[3].sha, &e->stages[3].mode);
 269         item = string_list_insert(path, entries);
 270         item->util = e;
 271         return e;
 272 }
 273
 274 /*
 275  * Create a dictionary mapping file names to stage_data objects. The
 276  * dictionary contains one entry for every path with a non-zero stage entry.
 277  */
 278 static struct string_list *get_unmerged(void)
 279 {
 280         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 281         int i;
 282
 283         unmerged->strdup_strings = 1;
 284
 285         for (i = 0; i < active_nr; i++) {
 286                 struct string_list_item *item;
 287                 struct stage_data *e;
 288                 struct cache_entry *ce = active_cache[i];
 289                 if (!ce_stage(ce))
 290                         continue;
 291
 292                 item = string_list_lookup(ce->name, unmerged);
 293                 if (!item) {
 294                         item = string_list_insert(ce->name, unmerged);
 295                         item->util = xcalloc(1, sizeof(struct stage_data));
 296                 }
 297                 e = item->util;
 298                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 299                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 300         }
 301
 302         return unmerged;
 303 }
 304
 305 struct rename
 306 {
 307         struct diff_filepair *pair;
 308         struct stage_data *src_entry;
 309         struct stage_data *dst_entry;
 310         unsigned processed:1;
 311 };
 312
 313 /*
 314  * Get information of all renames which occurred between 'o_tree' and
 315  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 316  * 'b_tree') to be able to associate the correct cache entries with
 317  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 318  */
 319 static struct string_list *get_renames(struct merge_options *o,
 320                                        struct tree *tree,
 321                                        struct tree *o_tree,
 322                                        struct tree *a_tree,
 323                                        struct tree *b_tree,
 324                                        struct string_list *entries)
 325 {
 326         int i;
 327         struct string_list *renames;
 328         struct diff_options opts;
 329
 330         renames = xcalloc(1, sizeof(struct string_list));
 331         diff_setup(&opts);
 332         DIFF_OPT_SET(&opts, RECURSIVE);
 333         opts.detect_rename = DIFF_DETECT_RENAME;
 334         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 335                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 336                             500;
 337         opts.warn_on_too_large_rename = 1;
 338         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 339         if (diff_setup_done(&opts) < 0)
 340                 die("diff setup failed");
 341         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 342         diffcore_std(&opts);
 343         for (i = 0; i < diff_queued_diff.nr; ++i) {
 344                 struct string_list_item *item;
 345                 struct rename *re;
 346                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 347                 if (pair->status != 'R') {
 348                         diff_free_filepair(pair);
 349                         continue;
 350                 }
 351                 re = xmalloc(sizeof(*re));
 352                 re->processed = 0;
 353                 re->pair = pair;
 354                 item = string_list_lookup(re->pair->one->path, entries);
 355                 if (!item)
 356                         re->src_entry = insert_stage_data(re->pair->one->path,
 357                                         o_tree, a_tree, b_tree, entries);
 358                 else
 359                         re->src_entry = item->util;
 360
 361                 item = string_list_lookup(re->pair->two->path, entries);
 362                 if (!item)
 363                         re->dst_entry = insert_stage_data(re->pair->two->path,
 364                                         o_tree, a_tree, b_tree, entries);
 365                 else
 366                         re->dst_entry = item->util;
 367                 item = string_list_insert(pair->one->path, renames);
 368                 item->util = re;
 369         }
 370         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 371         diff_queued_diff.nr = 0;
 372         diff_flush(&opts);
 373         return renames;
 374 }
 375
 376 static int update_stages(const char *path, struct diff_filespec *o,
 377                          struct diff_filespec *a, struct diff_filespec *b,
 378                          int clear)
 379 {
 380         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 381         if (clear)
 382                 if (remove_file_from_cache(path))
 383                         return -1;
 384         if (o)
 385                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 386                         return -1;
 387         if (a)
 388                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 389                         return -1;
 390         if (b)
 391                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 392                         return -1;
 393         return 0;
 394 }
 395
 396 static int remove_file(struct merge_options *o, int clean,
 397                        const char *path, int no_wd)
 398 {
 399         int update_cache = o->call_depth || clean;
 400         int update_working_directory = !o->call_depth && !no_wd;
 401
 402         if (update_cache) {
 403                 if (remove_file_from_cache(path))
 404                         return -1;
 405         }
 406         if (update_working_directory) {
 407                 if (remove_path(path) && errno != ENOENT)
 408                         return -1;
 409         }
 410         return 0;
 411 }
 412
 413 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 414 {
 415         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 416         int suffix = 0;
 417         struct stat st;
 418         char *p = newpath + strlen(path);
 419         strcpy(newpath, path);
 420         *(p++) = '~';
 421         strcpy(p, branch);
 422         for (; *p; ++p)
 423                 if ('/' == *p)
 424                         *p = '_';
 425         while (string_list_has_string(&o->current_file_set, newpath) ||
 426                string_list_has_string(&o->current_directory_set, newpath) ||
 427                lstat(newpath, &st) == 0)
 428                 sprintf(p, "_%d", suffix++);
 429
 430         string_list_insert(newpath, &o->current_file_set);
 431         return newpath;
 432 }
 433
 434 static void flush_buffer(int fd, const char *buf, unsigned long size)
 435 {
 436         while (size > 0) {
 437                 long ret = write_in_full(fd, buf, size);
 438                 if (ret < 0) {
 439                         /* Ignore epipe */
 440                         if (errno == EPIPE)
 441                                 break;
 442                         die("merge-recursive: %s", strerror(errno));
 443                 } else if (!ret) {
 444                         die("merge-recursive: disk full?");
 445                 }
 446                 size -= ret;
 447                 buf += ret;
 448         }
 449 }
 450
 451 static int make_room_for_path(const char *path)
 452 {
 453         int status;
 454         const char *msg = "failed to create path '%s'%s";
 455
 456         status = safe_create_leading_directories_const(path);
 457         if (status) {
 458                 if (status == -3) {
 459                         /* something else exists */
 460                         error(msg, path, ": perhaps a D/F conflict?");
 461                         return -1;
 462                 }
 463                 die(msg, path, "");
 464         }
 465
 466         /* Successful unlink is good.. */
 467         if (!unlink(path))
 468                 return 0;
 469         /* .. and so is no existing file */
 470         if (errno == ENOENT)
 471                 return 0;
 472         /* .. but not some other error (who really cares what?) */
 473         return error(msg, path, ": perhaps a D/F conflict?");
 474 }
 475
 476 static void update_file_flags(struct merge_options *o,
 477                               const unsigned char *sha,
 478                               unsigned mode,
 479                               const char *path,
 480                               int update_cache,
 481                               int update_wd)
 482 {
 483         if (o->call_depth)
 484                 update_wd = 0;
 485
 486         if (update_wd) {
 487                 enum object_type type;
 488                 void *buf;
 489                 unsigned long size;
 490
 491                 if (S_ISGITLINK(mode))
 492                         die("cannot read object %s '%s': It is a submodule!",
 493                             sha1_to_hex(sha), path);
 494
 495                 buf = read_sha1_file(sha, &type, &size);
 496                 if (!buf)
 497                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 498                 if (type != OBJ_BLOB)
 499                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 500                 if (S_ISREG(mode)) {
 501                         struct strbuf strbuf = STRBUF_INIT;
 502                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 503                                 free(buf);
 504                                 size = strbuf.len;
 505                                 buf = strbuf_detach(&strbuf, NULL);
 506                         }
 507                 }
 508
 509                 if (make_room_for_path(path) < 0) {
 510                         update_wd = 0;
 511                         free(buf);
 512                         goto update_index;
 513                 }
 514                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 515                         int fd;
 516                         if (mode & 0100)
 517                                 mode = 0777;
 518                         else
 519                                 mode = 0666;
 520                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 521                         if (fd < 0)
 522                                 die("failed to open %s: %s", path, strerror(errno));
 523                         flush_buffer(fd, buf, size);
 524                         close(fd);
 525                 } else if (S_ISLNK(mode)) {
 526                         char *lnk = xmemdupz(buf, size);
 527                         safe_create_leading_directories_const(path);
 528                         unlink(path);
 529                         symlink(lnk, path);
 530                         free(lnk);
 531                 } else
 532                         die("do not know what to do with %06o %s '%s'",
 533                             mode, sha1_to_hex(sha), path);
 534                 free(buf);
 535         }
 536  update_index:
 537         if (update_cache)
 538                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 539 }
 540
 541 static void update_file(struct merge_options *o,
 542                         int clean,
 543                         const unsigned char *sha,
 544                         unsigned mode,
 545                         const char *path)
 546 {
 547         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 548 }
 549
 550 /* Low level file merging, update and removal */
 551
 552 struct merge_file_info
 553 {
 554         unsigned char sha[20];
 555         unsigned mode;
 556         unsigned clean:1,
 557                  merge:1;
 558 };
 559
 560 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 561 {
 562         unsigned long size;
 563         enum object_type type;
 564
 565         if (!hashcmp(sha1, null_sha1)) {
 566                 mm->ptr = xstrdup("");
 567                 mm->size = 0;
 568                 return;
 569         }
 570
 571         mm->ptr = read_sha1_file(sha1, &type, &size);
 572         if (!mm->ptr || type != OBJ_BLOB)
 573                 die("unable to read blob object %s", sha1_to_hex(sha1));
 574         mm->size = size;
 575 }
 576
 577 static int merge_3way(struct merge_options *o,
 578                       mmbuffer_t *result_buf,
 579                       struct diff_filespec *one,
 580                       struct diff_filespec *a,
 581                       struct diff_filespec *b,
 582                       const char *branch1,
 583                       const char *branch2)
 584 {
 585         mmfile_t orig, src1, src2;
 586         char *name1, *name2;
 587         int merge_status;
 588
 589         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 590         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 591
 592         fill_mm(one->sha1, &orig);
 593         fill_mm(a->sha1, &src1);
 594         fill_mm(b->sha1, &src2);
 595
 596         merge_status = ll_merge(result_buf, a->path, &orig,
 597                                 &src1, name1, &src2, name2,
 598                                 o->call_depth);
 599
 600         free(name1);
 601         free(name2);
 602         free(orig.ptr);
 603         free(src1.ptr);
 604         free(src2.ptr);
 605         return merge_status;
 606 }
 607
 608 static struct merge_file_info merge_file(struct merge_options *o,
 609                                          struct diff_filespec *one,
 610                                          struct diff_filespec *a,
 611                                          struct diff_filespec *b,
 612                                          const char *branch1,
 613                                          const char *branch2)
 614 {
 615         struct merge_file_info result;
 616         result.merge = 0;
 617         result.clean = 1;
 618
 619         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 620                 result.clean = 0;
 621                 if (S_ISREG(a->mode)) {
 622                         result.mode = a->mode;
 623                         hashcpy(result.sha, a->sha1);
 624                 } else {
 625                         result.mode = b->mode;
 626                         hashcpy(result.sha, b->sha1);
 627                 }
 628         } else {
 629                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 630                         result.merge = 1;
 631
 632                 /*
 633                  * Merge modes
 634                  */
 635                 if (a->mode == b->mode || a->mode == one->mode)
 636                         result.mode = b->mode;
 637                 else {
 638                         result.mode = a->mode;
 639                         if (b->mode != one->mode) {
 640                                 result.clean = 0;
 641                                 result.merge = 1;
 642                         }
 643                 }
 644
 645                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 646                         hashcpy(result.sha, b->sha1);
 647                 else if (sha_eq(b->sha1, one->sha1))
 648                         hashcpy(result.sha, a->sha1);
 649                 else if (S_ISREG(a->mode)) {
 650                         mmbuffer_t result_buf;
 651                         int merge_status;
 652
 653                         merge_status = merge_3way(o, &result_buf, one, a, b,
 654                                                   branch1, branch2);
 655
 656                         if ((merge_status < 0) || !result_buf.ptr)
 657                                 die("Failed to execute internal merge");
 658
 659                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 660                                             blob_type, result.sha))
 661                                 die("Unable to add %s to database",
 662                                     a->path);
 663
 664                         free(result_buf.ptr);
 665                         result.clean = (merge_status == 0);
 666                 } else if (S_ISGITLINK(a->mode)) {
 667                         result.clean = 0;
 668                         hashcpy(result.sha, a->sha1);
 669                 } else if (S_ISLNK(a->mode)) {
 670                         hashcpy(result.sha, a->sha1);
 671
 672                         if (!sha_eq(a->sha1, b->sha1))
 673                                 result.clean = 0;
 674                 } else {
 675                         die("unsupported object type in the tree");
 676                 }
 677         }
 678
 679         return result;
 680 }
 681
 682 static void conflict_rename_rename(struct merge_options *o,
 683                                    struct rename *ren1,
 684                                    const char *branch1,
 685                                    struct rename *ren2,
 686                                    const char *branch2)
 687 {
 688         char *del[2];
 689         int delp = 0;
 690         const char *ren1_dst = ren1->pair->two->path;
 691         const char *ren2_dst = ren2->pair->two->path;
 692         const char *dst_name1 = ren1_dst;
 693         const char *dst_name2 = ren2_dst;
 694         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 695                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 696                 output(o, 1, "%s is a directory in %s adding as %s instead",
 697                        ren1_dst, branch2, dst_name1);
 698                 remove_file(o, 0, ren1_dst, 0);
 699         }
 700         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 701                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 702                 output(o, 1, "%s is a directory in %s adding as %s instead",
 703                        ren2_dst, branch1, dst_name2);
 704                 remove_file(o, 0, ren2_dst, 0);
 705         }
 706         if (o->call_depth) {
 707                 remove_file_from_cache(dst_name1);
 708                 remove_file_from_cache(dst_name2);
 709                 /*
 710                  * Uncomment to leave the conflicting names in the resulting tree
 711                  *
 712                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 713                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 714                  */
 715         } else {
 716                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 717                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 718         }
 719         while (delp--)
 720                 free(del[delp]);
 721 }
 722
 723 static void conflict_rename_dir(struct merge_options *o,
 724                                 struct rename *ren1,
 725                                 const char *branch1)
 726 {
 727         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 728         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 729         remove_file(o, 0, ren1->pair->two->path, 0);
 730         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 731         free(new_path);
 732 }
 733
 734 static void conflict_rename_rename_2(struct merge_options *o,
 735                                      struct rename *ren1,
 736                                      const char *branch1,
 737                                      struct rename *ren2,
 738                                      const char *branch2)
 739 {
 740         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 741         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 742         output(o, 1, "Renaming %s to %s and %s to %s instead",
 743                ren1->pair->one->path, new_path1,
 744                ren2->pair->one->path, new_path2);
 745         remove_file(o, 0, ren1->pair->two->path, 0);
 746         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 747         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 748         free(new_path2);
 749         free(new_path1);
 750 }
 751
 752 static int process_renames(struct merge_options *o,
 753                            struct string_list *a_renames,
 754                            struct string_list *b_renames)
 755 {
 756         int clean_merge = 1, i, j;
 757         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 758         const struct rename *sre;
 759
 760         for (i = 0; i < a_renames->nr; i++) {
 761                 sre = a_renames->items[i].util;
 762                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 763                         = sre->dst_entry;
 764         }
 765         for (i = 0; i < b_renames->nr; i++) {
 766                 sre = b_renames->items[i].util;
 767                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 768                         = sre->dst_entry;
 769         }
 770
 771         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 772                 int compare;
 773                 char *src;
 774                 struct string_list *renames1, *renames2, *renames2Dst;
 775                 struct rename *ren1 = NULL, *ren2 = NULL;
 776                 const char *branch1, *branch2;
 777                 const char *ren1_src, *ren1_dst;
 778
 779                 if (i >= a_renames->nr) {
 780                         compare = 1;
 781                         ren2 = b_renames->items[j++].util;
 782                 } else if (j >= b_renames->nr) {
 783                         compare = -1;
 784                         ren1 = a_renames->items[i++].util;
 785                 } else {
 786                         compare = strcmp(a_renames->items[i].string,
 787                                         b_renames->items[j].string);
 788                         if (compare <= 0)
 789                                 ren1 = a_renames->items[i++].util;
 790                         if (compare >= 0)
 791                                 ren2 = b_renames->items[j++].util;
 792                 }
 793
 794                 /* TODO: refactor, so that 1/2 are not needed */
 795                 if (ren1) {
 796                         renames1 = a_renames;
 797                         renames2 = b_renames;
 798                         renames2Dst = &b_by_dst;
 799                         branch1 = o->branch1;
 800                         branch2 = o->branch2;
 801                 } else {
 802                         struct rename *tmp;
 803                         renames1 = b_renames;
 804                         renames2 = a_renames;
 805                         renames2Dst = &a_by_dst;
 806                         branch1 = o->branch2;
 807                         branch2 = o->branch1;
 808                         tmp = ren2;
 809                         ren2 = ren1;
 810                         ren1 = tmp;
 811                 }
 812                 src = ren1->pair->one->path;
 813
 814                 ren1->dst_entry->processed = 1;
 815                 ren1->src_entry->processed = 1;
 816
 817                 if (ren1->processed)
 818                         continue;
 819                 ren1->processed = 1;
 820
 821                 ren1_src = ren1->pair->one->path;
 822                 ren1_dst = ren1->pair->two->path;
 823
 824                 if (ren2) {
 825                         const char *ren2_src = ren2->pair->one->path;
 826                         const char *ren2_dst = ren2->pair->two->path;
 827                         /* Renamed in 1 and renamed in 2 */
 828                         if (strcmp(ren1_src, ren2_src) != 0)
 829                                 die("ren1.src != ren2.src");
 830                         ren2->dst_entry->processed = 1;
 831                         ren2->processed = 1;
 832                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 833                                 clean_merge = 0;
 834                                 output(o, 1, "CONFLICT (rename/rename): "
 835                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 836                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 837                                        src, ren1_dst, branch1,
 838                                        src, ren2_dst, branch2,
 839                                        o->call_depth ? " (left unresolved)": "");
 840                                 if (o->call_depth) {
 841                                         remove_file_from_cache(src);
 842                                         update_file(o, 0, ren1->pair->one->sha1,
 843                                                     ren1->pair->one->mode, src);
 844                                 }
 845                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 846                         } else {
 847                                 struct merge_file_info mfi;
 848                                 remove_file(o, 1, ren1_src, 1);
 849                                 mfi = merge_file(o,
 850                                                  ren1->pair->one,
 851                                                  ren1->pair->two,
 852                                                  ren2->pair->two,
 853                                                  branch1,
 854                                                  branch2);
 855                                 if (mfi.merge || !mfi.clean)
 856                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 857
 858                                 if (mfi.merge)
 859                                         output(o, 2, "Auto-merging %s", ren1_dst);
 860
 861                                 if (!mfi.clean) {
 862                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 863                                                ren1_dst);
 864                                         clean_merge = 0;
 865
 866                                         if (!o->call_depth)
 867                                                 update_stages(ren1_dst,
 868                                                               ren1->pair->one,
 869                                                               ren1->pair->two,
 870                                                               ren2->pair->two,
 871                                                               1 /* clear */);
 872                                 }
 873                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 874                         }
 875                 } else {
 876                         /* Renamed in 1, maybe changed in 2 */
 877                         struct string_list_item *item;
 878                         /* we only use sha1 and mode of these */
 879                         struct diff_filespec src_other, dst_other;
 880                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 881
 882                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 883
 884                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 885                         src_other.mode = ren1->src_entry->stages[stage].mode;
 886                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 887                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 888
 889                         try_merge = 0;
 890
 891                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 892                                 clean_merge = 0;
 893                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 894                                        " directory %s added in %s",
 895                                        ren1_src, ren1_dst, branch1,
 896                                        ren1_dst, branch2);
 897                                 conflict_rename_dir(o, ren1, branch1);
 898                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 899                                 clean_merge = 0;
 900                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 901                                        "and deleted in %s",
 902                                        ren1_src, ren1_dst, branch1,
 903                                        branch2);
 904                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 905                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 906                                 const char *new_path;
 907                                 clean_merge = 0;
 908                                 try_merge = 1;
 909                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 910                                        "%s added in %s",
 911                                        ren1_src, ren1_dst, branch1,
 912                                        ren1_dst, branch2);
 913                                 new_path = unique_path(o, ren1_dst, branch2);
 914                                 output(o, 1, "Adding as %s instead", new_path);
 915                                 update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 916                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 917                                 ren2 = item->util;
 918                                 clean_merge = 0;
 919                                 ren2->processed = 1;
 920                                 output(o, 1, "CONFLICT (rename/rename): "
 921                                        "Rename %s->%s in %s. "
 922                                        "Rename %s->%s in %s",
 923                                        ren1_src, ren1_dst, branch1,
 924                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 925                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
 926                         } else
 927                                 try_merge = 1;
 928
 929                         if (try_merge) {
 930                                 struct diff_filespec *one, *a, *b;
 931                                 struct merge_file_info mfi;
 932                                 src_other.path = (char *)ren1_src;
 933
 934                                 one = ren1->pair->one;
 935                                 if (a_renames == renames1) {
 936                                         a = ren1->pair->two;
 937                                         b = &src_other;
 938                                 } else {
 939                                         b = ren1->pair->two;
 940                                         a = &src_other;
 941                                 }
 942                                 mfi = merge_file(o, one, a, b,
 943                                                 o->branch1, o->branch2);
 944
 945                                 if (mfi.clean &&
 946                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
 947                                     mfi.mode == ren1->pair->two->mode)
 948                                         /*
 949                                          * This messaged is part of
 950                                          * t6022 test. If you change
 951                                          * it update the test too.
 952                                          */
 953                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
 954                                 else {
 955                                         if (mfi.merge || !mfi.clean)
 956                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
 957                                         if (mfi.merge)
 958                                                 output(o, 2, "Auto-merging %s", ren1_dst);
 959                                         if (!mfi.clean) {
 960                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
 961                                                        ren1_dst);
 962                                                 clean_merge = 0;
 963
 964                                                 if (!o->call_depth)
 965                                                         update_stages(ren1_dst,
 966                                                                       one, a, b, 1);
 967                                         }
 968                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 969                                 }
 970                         }
 971                 }
 972         }
 973         string_list_clear(&a_by_dst, 0);
 974         string_list_clear(&b_by_dst, 0);
 975
 976         return clean_merge;
 977 }
 978
 979 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 980 {
 981         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 982 }
 983
 984 /* Per entry merge function */
 985 static int process_entry(struct merge_options *o,
 986                          const char *path, struct stage_data *entry)
 987 {
 988         /*
 989         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
 990         print_index_entry("\tpath: ", entry);
 991         */
 992         int clean_merge = 1;
 993         unsigned o_mode = entry->stages[1].mode;
 994         unsigned a_mode = entry->stages[2].mode;
 995         unsigned b_mode = entry->stages[3].mode;
 996         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
 997         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
 998         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
 999
1000         if (o_sha && (!a_sha || !b_sha)) {
1001                 /* Case A: Deleted in one */
1002                 if ((!a_sha && !b_sha) ||
1003                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1004                     (!a_sha && sha_eq(b_sha, o_sha))) {
1005                         /* Deleted in both or deleted in one and
1006                          * unchanged in the other */
1007                         if (a_sha)
1008                                 output(o, 2, "Removing %s", path);
1009                         /* do not touch working file if it did not exist */
1010                         remove_file(o, 1, path, !a_sha);
1011                 } else {
1012                         /* Deleted in one and changed in the other */
1013                         clean_merge = 0;
1014                         if (!a_sha) {
1015                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1016                                        "and modified in %s. Version %s of %s left in tree.",
1017                                        path, o->branch1,
1018                                        o->branch2, o->branch2, path);
1019                                 update_file(o, 0, b_sha, b_mode, path);
1020                         } else {
1021                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1022                                        "and modified in %s. Version %s of %s left in tree.",
1023                                        path, o->branch2,
1024                                        o->branch1, o->branch1, path);
1025                                 update_file(o, 0, a_sha, a_mode, path);
1026                         }
1027                 }
1028
1029         } else if ((!o_sha && a_sha && !b_sha) ||
1030                    (!o_sha && !a_sha && b_sha)) {
1031                 /* Case B: Added in one. */
1032                 const char *add_branch;
1033                 const char *other_branch;
1034                 unsigned mode;
1035                 const unsigned char *sha;
1036                 const char *conf;
1037
1038                 if (a_sha) {
1039                         add_branch = o->branch1;
1040                         other_branch = o->branch2;
1041                         mode = a_mode;
1042                         sha = a_sha;
1043                         conf = "file/directory";
1044                 } else {
1045                         add_branch = o->branch2;
1046                         other_branch = o->branch1;
1047                         mode = b_mode;
1048                         sha = b_sha;
1049                         conf = "directory/file";
1050                 }
1051                 if (string_list_has_string(&o->current_directory_set, path)) {
1052                         const char *new_path = unique_path(o, path, add_branch);
1053                         clean_merge = 0;
1054                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1055                                "Adding %s as %s",
1056                                conf, path, other_branch, path, new_path);
1057                         remove_file(o, 0, path, 0);
1058                         update_file(o, 0, sha, mode, new_path);
1059                 } else {
1060                         output(o, 2, "Adding %s", path);
1061                         update_file(o, 1, sha, mode, path);
1062                 }
1063         } else if (a_sha && b_sha) {
1064                 /* Case C: Added in both (check for same permissions) and */
1065                 /* case D: Modified in both, but differently. */
1066                 const char *reason = "content";
1067                 struct merge_file_info mfi;
1068                 struct diff_filespec one, a, b;
1069
1070                 if (!o_sha) {
1071                         reason = "add/add";
1072                         o_sha = (unsigned char *)null_sha1;
1073                 }
1074                 output(o, 2, "Auto-merging %s", path);
1075                 one.path = a.path = b.path = (char *)path;
1076                 hashcpy(one.sha1, o_sha);
1077                 one.mode = o_mode;
1078                 hashcpy(a.sha1, a_sha);
1079                 a.mode = a_mode;
1080                 hashcpy(b.sha1, b_sha);
1081                 b.mode = b_mode;
1082
1083                 mfi = merge_file(o, &one, &a, &b,
1084                                  o->branch1, o->branch2);
1085
1086                 clean_merge = mfi.clean;
1087                 if (mfi.clean)
1088                         update_file(o, 1, mfi.sha, mfi.mode, path);
1089                 else if (S_ISGITLINK(mfi.mode))
1090                         output(o, 1, "CONFLICT (submodule): Merge conflict in %s "
1091                                "- needs %s", path, sha1_to_hex(b.sha1));
1092                 else {
1093                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1094                                         reason, path);
1095
1096                         if (o->call_depth)
1097                                 update_file(o, 0, mfi.sha, mfi.mode, path);
1098                         else
1099                                 update_file_flags(o, mfi.sha, mfi.mode, path,
1100                                               0 /* update_cache */, 1 /* update_working_directory */);
1101                 }
1102         } else if (!o_sha && !a_sha && !b_sha) {
1103                 /*
1104                  * this entry was deleted altogether. a_mode == 0 means
1105                  * we had that path and want to actively remove it.
1106                  */
1107                 remove_file(o, 1, path, !a_mode);
1108         } else
1109                 die("Fatal merge failure, shouldn't happen.");
1110
1111         return clean_merge;
1112 }
1113
1114 int merge_trees(struct merge_options *o,
1115                 struct tree *head,
1116                 struct tree *merge,
1117                 struct tree *common,
1118                 struct tree **result)
1119 {
1120         int code, clean;
1121
1122         if (o->subtree_merge) {
1123                 merge = shift_tree_object(head, merge);
1124                 common = shift_tree_object(head, common);
1125         }
1126
1127         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1128                 output(o, 0, "Already uptodate!");
1129                 *result = head;
1130                 return 1;
1131         }
1132
1133         code = git_merge_trees(o->call_depth, common, head, merge);
1134
1135         if (code != 0)
1136                 die("merging of trees %s and %s failed",
1137                     sha1_to_hex(head->object.sha1),
1138                     sha1_to_hex(merge->object.sha1));
1139
1140         if (unmerged_cache()) {
1141                 struct string_list *entries, *re_head, *re_merge;
1142                 int i;
1143                 string_list_clear(&o->current_file_set, 1);
1144                 string_list_clear(&o->current_directory_set, 1);
1145                 get_files_dirs(o, head);
1146                 get_files_dirs(o, merge);
1147
1148                 entries = get_unmerged();
1149                 re_head  = get_renames(o, head, common, head, merge, entries);
1150                 re_merge = get_renames(o, merge, common, head, merge, entries);
1151                 clean = process_renames(o, re_head, re_merge);
1152                 for (i = 0; i < entries->nr; i++) {
1153                         const char *path = entries->items[i].string;
1154                         struct stage_data *e = entries->items[i].util;
1155                         if (!e->processed
1156                                 && !process_entry(o, path, e))
1157                                 clean = 0;
1158                 }
1159
1160                 string_list_clear(re_merge, 0);
1161                 string_list_clear(re_head, 0);
1162                 string_list_clear(entries, 1);
1163
1164         }
1165         else
1166                 clean = 1;
1167
1168         if (o->call_depth)
1169                 *result = write_tree_from_memory(o);
1170
1171         return clean;
1172 }
1173
1174 static struct commit_list *reverse_commit_list(struct commit_list *list)
1175 {
1176         struct commit_list *next = NULL, *current, *backup;
1177         for (current = list; current; current = backup) {
1178                 backup = current->next;
1179                 current->next = next;
1180                 next = current;
1181         }
1182         return next;
1183 }
1184
1185 /*
1186  * Merge the commits h1 and h2, return the resulting virtual
1187  * commit object and a flag indicating the cleanness of the merge.
1188  */
1189 int merge_recursive(struct merge_options *o,
1190                     struct commit *h1,
1191                     struct commit *h2,
1192                     struct commit_list *ca,
1193                     struct commit **result)
1194 {
1195         struct commit_list *iter;
1196         struct commit *merged_common_ancestors;
1197         struct tree *mrtree = mrtree;
1198         int clean;
1199
1200         if (show(o, 4)) {
1201                 output(o, 4, "Merging:");
1202                 output_commit_title(o, h1);
1203                 output_commit_title(o, h2);
1204         }
1205
1206         if (!ca) {
1207                 ca = get_merge_bases(h1, h2, 1);
1208                 ca = reverse_commit_list(ca);
1209         }
1210
1211         if (show(o, 5)) {
1212                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1213                 for (iter = ca; iter; iter = iter->next)
1214                         output_commit_title(o, iter->item);
1215         }
1216
1217         merged_common_ancestors = pop_commit(&ca);
1218         if (merged_common_ancestors == NULL) {
1219                 /* if there is no common ancestor, make an empty tree */
1220                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1221
1222                 tree->object.parsed = 1;
1223                 tree->object.type = OBJ_TREE;
1224                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1225                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1226         }
1227
1228         for (iter = ca; iter; iter = iter->next) {
1229                 const char *saved_b1, *saved_b2;
1230                 o->call_depth++;
1231                 /*
1232                  * When the merge fails, the result contains files
1233                  * with conflict markers. The cleanness flag is
1234                  * ignored, it was never actually used, as result of
1235                  * merge_trees has always overwritten it: the committed
1236                  * "conflicts" were already resolved.
1237                  */
1238                 discard_cache();
1239                 saved_b1 = o->branch1;
1240                 saved_b2 = o->branch2;
1241                 o->branch1 = "Temporary merge branch 1";
1242                 o->branch2 = "Temporary merge branch 2";
1243                 merge_recursive(o, merged_common_ancestors, iter->item,
1244                                 NULL, &merged_common_ancestors);
1245                 o->branch1 = saved_b1;
1246                 o->branch2 = saved_b2;
1247                 o->call_depth--;
1248
1249                 if (!merged_common_ancestors)
1250                         die("merge returned no commit");
1251         }
1252
1253         discard_cache();
1254         if (!o->call_depth)
1255                 read_cache();
1256
1257         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1258                             &mrtree);
1259
1260         if (o->call_depth) {
1261                 *result = make_virtual_commit(mrtree, "merged tree");
1262                 commit_list_insert(h1, &(*result)->parents);
1263                 commit_list_insert(h2, &(*result)->parents->next);
1264         }
1265         flush_output(o);
1266         return clean;
1267 }
1268
1269 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1270 {
1271         struct object *object;
1272
1273         object = deref_tag(parse_object(sha1), name, strlen(name));
1274         if (!object)
1275                 return NULL;
1276         if (object->type == OBJ_TREE)
1277                 return make_virtual_commit((struct tree*)object, name);
1278         if (object->type != OBJ_COMMIT)
1279                 return NULL;
1280         if (parse_commit((struct commit *)object))
1281                 return NULL;
1282         return (struct commit *)object;
1283 }
1284
1285 int merge_recursive_generic(struct merge_options *o,
1286                             const unsigned char *head,
1287                             const unsigned char *merge,
1288                             int num_base_list,
1289                             const unsigned char **base_list,
1290                             struct commit **result)
1291 {
1292         int clean, index_fd;
1293         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1294         struct commit *head_commit = get_ref(head, o->branch1);
1295         struct commit *next_commit = get_ref(merge, o->branch2);
1296         struct commit_list *ca = NULL;
1297
1298         if (base_list) {
1299                 int i;
1300                 for (i = 0; i < num_base_list; ++i) {
1301                         struct commit *base;
1302                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1303                                 return error("Could not parse object '%s'",
1304                                         sha1_to_hex(base_list[i]));
1305                         commit_list_insert(base, &ca);
1306                 }
1307         }
1308
1309         index_fd = hold_locked_index(lock, 1);
1310         clean = merge_recursive(o, head_commit, next_commit, ca,
1311                         result);
1312         if (active_cache_changed &&
1313                         (write_cache(index_fd, active_cache, active_nr) ||
1314                          commit_locked_index(lock)))
1315                 return error("Unable to write index.");
1316
1317         return clean ? 0 : 1;
1318 }
1319
1320 static int merge_recursive_config(const char *var, const char *value, void *cb)
1321 {
1322         struct merge_options *o = cb;
1323         if (!strcasecmp(var, "merge.verbosity")) {
1324                 o->verbosity = git_config_int(var, value);
1325                 return 0;
1326         }
1327         if (!strcasecmp(var, "diff.renamelimit")) {
1328                 o->diff_rename_limit = git_config_int(var, value);
1329                 return 0;
1330         }
1331         if (!strcasecmp(var, "merge.renamelimit")) {
1332                 o->merge_rename_limit = git_config_int(var, value);
1333                 return 0;
1334         }
1335         return git_xmerge_config(var, value, cb);
1336 }
1337
1338 void init_merge_options(struct merge_options *o)
1339 {
1340         memset(o, 0, sizeof(struct merge_options));
1341         o->verbosity = 2;
1342         o->buffer_output = 1;
1343         o->diff_rename_limit = -1;
1344         o->merge_rename_limit = -1;
1345         git_config(merge_recursive_config, o);
1346         if (getenv("GIT_MERGE_VERBOSITY"))
1347                 o->verbosity =
1348                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1349         if (o->verbosity >= 5)
1350                 o->buffer_output = 0;
1351         strbuf_init(&o->obuf, 0);
1352         memset(&o->current_file_set, 0, sizeof(struct string_list));
1353         o->current_file_set.strdup_strings = 1;
1354         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1355         o->current_directory_set.strdup_strings = 1;
1356 }