merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "cache.h"
   7 #include "cache-tree.h"
   8 #include "commit.h"
   9 #include "blob.h"
  10 #include "builtin.h"
  11 #include "tree-walk.h"
  12 #include "diff.h"
  13 #include "diffcore.h"
  14 #include "tag.h"
  15 #include "unpack-trees.h"
  16 #include "string-list.h"
  17 #include "xdiff-interface.h"
  18 #include "ll-merge.h"
  19 #include "interpolate.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22
  23 static 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
  39  * - (const char *)commit->util set to the name, and
  40  * - *(int *)commit->object.sha1 set to the virtual id.
  41  */
  42
  43 struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  44 {
  45         struct commit *commit = xcalloc(1, sizeof(struct commit));
  46         static unsigned virtual_id = 1;
  47         commit->tree = tree;
  48         commit->util = (void*)comment;
  49         *(int*)commit->object.sha1 = virtual_id++;
  50         /* avoid warnings */
  51         commit->object.parsed = 1;
  52         return commit;
  53 }
  54
  55 /*
  56  * Since we use get_tree_entry(), which does not put the read object into
  57  * the object pool, we cannot rely on a == b.
  58  */
  59 static int sha_eq(const unsigned char *a, const unsigned char *b)
  60 {
  61         if (!a && !b)
  62                 return 2;
  63         return a && b && hashcmp(a, b) == 0;
  64 }
  65
  66 /*
  67  * Since we want to write the index eventually, we cannot reuse the index
  68  * for these (temporary) data.
  69  */
  70 struct stage_data
  71 {
  72         struct
  73         {
  74                 unsigned mode;
  75                 unsigned char sha[20];
  76         } stages[4];
  77         unsigned processed:1;
  78 };
  79
  80 static struct string_list current_file_set = {NULL, 0, 0, 1};
  81 static struct string_list current_directory_set = {NULL, 0, 0, 1};
  82
  83 static int show(struct merge_options *o, int v)
  84 {
  85         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  86 }
  87
  88 static void flush_output(struct merge_options *o)
  89 {
  90         if (o->obuf.len) {
  91                 fputs(o->obuf.buf, stdout);
  92                 strbuf_reset(&o->obuf);
  93         }
  94 }
  95
  96 static void output(struct merge_options *o, int v, const char *fmt, ...)
  97 {
  98         int len;
  99         va_list ap;
 100
 101         if (!show(o, v))
 102                 return;
 103
 104         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 105         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 106         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 107
 108         va_start(ap, fmt);
 109         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 110         va_end(ap);
 111
 112         if (len < 0)
 113                 len = 0;
 114         if (len >= strbuf_avail(&o->obuf)) {
 115                 strbuf_grow(&o->obuf, len + 2);
 116                 va_start(ap, fmt);
 117                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 118                 va_end(ap);
 119                 if (len >= strbuf_avail(&o->obuf)) {
 120                         die("this should not happen, your snprintf is broken");
 121                 }
 122         }
 123         strbuf_setlen(&o->obuf, o->obuf.len + len);
 124         strbuf_add(&o->obuf, "\n", 1);
 125         if (!o->buffer_output)
 126                 flush_output(o);
 127 }
 128
 129 static void output_commit_title(struct merge_options *o, struct commit *commit)
 130 {
 131         int i;
 132         flush_output(o);
 133         for (i = o->call_depth; i--;)
 134                 fputs("  ", stdout);
 135         if (commit->util)
 136                 printf("virtual %s\n", (char *)commit->util);
 137         else {
 138                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 139                 if (parse_commit(commit) != 0)
 140                         printf("(bad commit)\n");
 141                 else {
 142                         const char *s;
 143                         int len;
 144                         for (s = commit->buffer; *s; s++)
 145                                 if (*s == '\n' && s[1] == '\n') {
 146                                         s += 2;
 147                                         break;
 148                                 }
 149                         for (len = 0; s[len] && '\n' != s[len]; len++)
 150                                 ; /* do nothing */
 151                         printf("%.*s\n", len, s);
 152                 }
 153         }
 154 }
 155
 156 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 157                 const char *path, int stage, int refresh, int options)
 158 {
 159         struct cache_entry *ce;
 160         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 161         if (!ce)
 162                 return error("addinfo_cache failed for path '%s'", path);
 163         return add_cache_entry(ce, options);
 164 }
 165
 166 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 167 {
 168         parse_tree(tree);
 169         init_tree_desc(desc, tree->buffer, tree->size);
 170 }
 171
 172 static int git_merge_trees(int index_only,
 173                            struct tree *common,
 174                            struct tree *head,
 175                            struct tree *merge)
 176 {
 177         int rc;
 178         struct tree_desc t[3];
 179         struct unpack_trees_options opts;
 180
 181         memset(&opts, 0, sizeof(opts));
 182         if (index_only)
 183                 opts.index_only = 1;
 184         else
 185                 opts.update = 1;
 186         opts.merge = 1;
 187         opts.head_idx = 2;
 188         opts.fn = threeway_merge;
 189         opts.src_index = &the_index;
 190         opts.dst_index = &the_index;
 191
 192         init_tree_desc_from_tree(t+0, common);
 193         init_tree_desc_from_tree(t+1, head);
 194         init_tree_desc_from_tree(t+2, merge);
 195
 196         rc = unpack_trees(3, t, &opts);
 197         cache_tree_free(&active_cache_tree);
 198         return rc;
 199 }
 200
 201 struct tree *write_tree_from_memory(struct merge_options *o)
 202 {
 203         struct tree *result = NULL;
 204
 205         if (unmerged_cache()) {
 206                 int i;
 207                 output(o, 0, "There are unmerged index entries:");
 208                 for (i = 0; i < active_nr; i++) {
 209                         struct cache_entry *ce = active_cache[i];
 210                         if (ce_stage(ce))
 211                                 output(o, 0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 212                 }
 213                 return NULL;
 214         }
 215
 216         if (!active_cache_tree)
 217                 active_cache_tree = cache_tree();
 218
 219         if (!cache_tree_fully_valid(active_cache_tree) &&
 220             cache_tree_update(active_cache_tree,
 221                               active_cache, active_nr, 0, 0) < 0)
 222                 die("error building trees");
 223
 224         result = lookup_tree(active_cache_tree->sha1);
 225
 226         return result;
 227 }
 228
 229 static int save_files_dirs(const unsigned char *sha1,
 230                 const char *base, int baselen, const char *path,
 231                 unsigned int mode, int stage, void *context)
 232 {
 233         int len = strlen(path);
 234         char *newpath = xmalloc(baselen + len + 1);
 235         memcpy(newpath, base, baselen);
 236         memcpy(newpath + baselen, path, len);
 237         newpath[baselen + len] = '\0';
 238
 239         if (S_ISDIR(mode))
 240                 string_list_insert(newpath, &current_directory_set);
 241         else
 242                 string_list_insert(newpath, &current_file_set);
 243         free(newpath);
 244
 245         return READ_TREE_RECURSIVE;
 246 }
 247
 248 static int get_files_dirs(struct tree *tree)
 249 {
 250         int n;
 251         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, NULL))
 252                 return 0;
 253         n = current_file_set.nr + current_directory_set.nr;
 254         return n;
 255 }
 256
 257 /*
 258  * Returns an index_entry instance which doesn't have to correspond to
 259  * a real cache entry in Git's index.
 260  */
 261 static struct stage_data *insert_stage_data(const char *path,
 262                 struct tree *o, struct tree *a, struct tree *b,
 263                 struct string_list *entries)
 264 {
 265         struct string_list_item *item;
 266         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 267         get_tree_entry(o->object.sha1, path,
 268                         e->stages[1].sha, &e->stages[1].mode);
 269         get_tree_entry(a->object.sha1, path,
 270                         e->stages[2].sha, &e->stages[2].mode);
 271         get_tree_entry(b->object.sha1, path,
 272                         e->stages[3].sha, &e->stages[3].mode);
 273         item = string_list_insert(path, entries);
 274         item->util = e;
 275         return e;
 276 }
 277
 278 /*
 279  * Create a dictionary mapping file names to stage_data objects. The
 280  * dictionary contains one entry for every path with a non-zero stage entry.
 281  */
 282 static struct string_list *get_unmerged(void)
 283 {
 284         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 285         int i;
 286
 287         unmerged->strdup_strings = 1;
 288
 289         for (i = 0; i < active_nr; i++) {
 290                 struct string_list_item *item;
 291                 struct stage_data *e;
 292                 struct cache_entry *ce = active_cache[i];
 293                 if (!ce_stage(ce))
 294                         continue;
 295
 296                 item = string_list_lookup(ce->name, unmerged);
 297                 if (!item) {
 298                         item = string_list_insert(ce->name, unmerged);
 299                         item->util = xcalloc(1, sizeof(struct stage_data));
 300                 }
 301                 e = item->util;
 302                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 303                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 304         }
 305
 306         return unmerged;
 307 }
 308
 309 struct rename
 310 {
 311         struct diff_filepair *pair;
 312         struct stage_data *src_entry;
 313         struct stage_data *dst_entry;
 314         unsigned processed:1;
 315 };
 316
 317 /*
 318  * Get information of all renames which occurred between 'o_tree' and
 319  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 320  * 'b_tree') to be able to associate the correct cache entries with
 321  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 322  */
 323 static struct string_list *get_renames(struct merge_options *o,
 324                                        struct tree *tree,
 325                                        struct tree *o_tree,
 326                                        struct tree *a_tree,
 327                                        struct tree *b_tree,
 328                                        struct string_list *entries)
 329 {
 330         int i;
 331         struct string_list *renames;
 332         struct diff_options opts;
 333
 334         renames = xcalloc(1, sizeof(struct string_list));
 335         diff_setup(&opts);
 336         DIFF_OPT_SET(&opts, RECURSIVE);
 337         opts.detect_rename = DIFF_DETECT_RENAME;
 338         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 339                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 340                             500;
 341         opts.warn_on_too_large_rename = 1;
 342         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 343         if (diff_setup_done(&opts) < 0)
 344                 die("diff setup failed");
 345         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 346         diffcore_std(&opts);
 347         for (i = 0; i < diff_queued_diff.nr; ++i) {
 348                 struct string_list_item *item;
 349                 struct rename *re;
 350                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 351                 if (pair->status != 'R') {
 352                         diff_free_filepair(pair);
 353                         continue;
 354                 }
 355                 re = xmalloc(sizeof(*re));
 356                 re->processed = 0;
 357                 re->pair = pair;
 358                 item = string_list_lookup(re->pair->one->path, entries);
 359                 if (!item)
 360                         re->src_entry = insert_stage_data(re->pair->one->path,
 361                                         o_tree, a_tree, b_tree, entries);
 362                 else
 363                         re->src_entry = item->util;
 364
 365                 item = string_list_lookup(re->pair->two->path, entries);
 366                 if (!item)
 367                         re->dst_entry = insert_stage_data(re->pair->two->path,
 368                                         o_tree, a_tree, b_tree, entries);
 369                 else
 370                         re->dst_entry = item->util;
 371                 item = string_list_insert(pair->one->path, renames);
 372                 item->util = re;
 373         }
 374         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 375         diff_queued_diff.nr = 0;
 376         diff_flush(&opts);
 377         return renames;
 378 }
 379
 380 static int update_stages(const char *path, struct diff_filespec *o,
 381                          struct diff_filespec *a, struct diff_filespec *b,
 382                          int clear)
 383 {
 384         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 385         if (clear)
 386                 if (remove_file_from_cache(path))
 387                         return -1;
 388         if (o)
 389                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 390                         return -1;
 391         if (a)
 392                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 393                         return -1;
 394         if (b)
 395                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 396                         return -1;
 397         return 0;
 398 }
 399
 400 static int remove_path(const char *name)
 401 {
 402         int ret;
 403         char *slash, *dirs;
 404
 405         ret = unlink(name);
 406         if (ret)
 407                 return ret;
 408         dirs = xstrdup(name);
 409         while ((slash = strrchr(name, '/'))) {
 410                 *slash = '\0';
 411                 if (rmdir(name) != 0)
 412                         break;
 413         }
 414         free(dirs);
 415         return ret;
 416 }
 417
 418 static int remove_file(struct merge_options *o, int clean,
 419                        const char *path, int no_wd)
 420 {
 421         int update_cache = o->call_depth || clean;
 422         int update_working_directory = !o->call_depth && !no_wd;
 423
 424         if (update_cache) {
 425                 if (remove_file_from_cache(path))
 426                         return -1;
 427         }
 428         if (update_working_directory) {
 429                 unlink(path);
 430                 if (errno != ENOENT || errno != EISDIR)
 431                         return -1;
 432                 remove_path(path);
 433         }
 434         return 0;
 435 }
 436
 437 static char *unique_path(const char *path, const char *branch)
 438 {
 439         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 440         int suffix = 0;
 441         struct stat st;
 442         char *p = newpath + strlen(path);
 443         strcpy(newpath, path);
 444         *(p++) = '~';
 445         strcpy(p, branch);
 446         for (; *p; ++p)
 447                 if ('/' == *p)
 448                         *p = '_';
 449         while (string_list_has_string(&current_file_set, newpath) ||
 450                string_list_has_string(&current_directory_set, newpath) ||
 451                lstat(newpath, &st) == 0)
 452                 sprintf(p, "_%d", suffix++);
 453
 454         string_list_insert(newpath, &current_file_set);
 455         return newpath;
 456 }
 457
 458 static void flush_buffer(int fd, const char *buf, unsigned long size)
 459 {
 460         while (size > 0) {
 461                 long ret = write_in_full(fd, buf, size);
 462                 if (ret < 0) {
 463                         /* Ignore epipe */
 464                         if (errno == EPIPE)
 465                                 break;
 466                         die("merge-recursive: %s", strerror(errno));
 467                 } else if (!ret) {
 468                         die("merge-recursive: disk full?");
 469                 }
 470                 size -= ret;
 471                 buf += ret;
 472         }
 473 }
 474
 475 static int make_room_for_path(const char *path)
 476 {
 477         int status;
 478         const char *msg = "failed to create path '%s'%s";
 479
 480         status = safe_create_leading_directories_const(path);
 481         if (status) {
 482                 if (status == -3) {
 483                         /* something else exists */
 484                         error(msg, path, ": perhaps a D/F conflict?");
 485                         return -1;
 486                 }
 487                 die(msg, path, "");
 488         }
 489
 490         /* Successful unlink is good.. */
 491         if (!unlink(path))
 492                 return 0;
 493         /* .. and so is no existing file */
 494         if (errno == ENOENT)
 495                 return 0;
 496         /* .. but not some other error (who really cares what?) */
 497         return error(msg, path, ": perhaps a D/F conflict?");
 498 }
 499
 500 static void update_file_flags(struct merge_options *o,
 501                               const unsigned char *sha,
 502                               unsigned mode,
 503                               const char *path,
 504                               int update_cache,
 505                               int update_wd)
 506 {
 507         if (o->call_depth)
 508                 update_wd = 0;
 509
 510         if (update_wd) {
 511                 enum object_type type;
 512                 void *buf;
 513                 unsigned long size;
 514
 515                 if (S_ISGITLINK(mode))
 516                         die("cannot read object %s '%s': It is a submodule!",
 517                             sha1_to_hex(sha), path);
 518
 519                 buf = read_sha1_file(sha, &type, &size);
 520                 if (!buf)
 521                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 522                 if (type != OBJ_BLOB)
 523                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 524                 if (S_ISREG(mode)) {
 525                         struct strbuf strbuf;
 526                         strbuf_init(&strbuf, 0);
 527                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 528                                 free(buf);
 529                                 size = strbuf.len;
 530                                 buf = strbuf_detach(&strbuf, NULL);
 531                         }
 532                 }
 533
 534                 if (make_room_for_path(path) < 0) {
 535                         update_wd = 0;
 536                         free(buf);
 537                         goto update_index;
 538                 }
 539                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 540                         int fd;
 541                         if (mode & 0100)
 542                                 mode = 0777;
 543                         else
 544                                 mode = 0666;
 545                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 546                         if (fd < 0)
 547                                 die("failed to open %s: %s", path, strerror(errno));
 548                         flush_buffer(fd, buf, size);
 549                         close(fd);
 550                 } else if (S_ISLNK(mode)) {
 551                         char *lnk = xmemdupz(buf, size);
 552                         safe_create_leading_directories_const(path);
 553                         unlink(path);
 554                         symlink(lnk, path);
 555                         free(lnk);
 556                 } else
 557                         die("do not know what to do with %06o %s '%s'",
 558                             mode, sha1_to_hex(sha), path);
 559                 free(buf);
 560         }
 561  update_index:
 562         if (update_cache)
 563                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 564 }
 565
 566 static void update_file(struct merge_options *o,
 567                         int clean,
 568                         const unsigned char *sha,
 569                         unsigned mode,
 570                         const char *path)
 571 {
 572         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 573 }
 574
 575 /* Low level file merging, update and removal */
 576
 577 struct merge_file_info
 578 {
 579         unsigned char sha[20];
 580         unsigned mode;
 581         unsigned clean:1,
 582                  merge:1;
 583 };
 584
 585 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 586 {
 587         unsigned long size;
 588         enum object_type type;
 589
 590         if (!hashcmp(sha1, null_sha1)) {
 591                 mm->ptr = xstrdup("");
 592                 mm->size = 0;
 593                 return;
 594         }
 595
 596         mm->ptr = read_sha1_file(sha1, &type, &size);
 597         if (!mm->ptr || type != OBJ_BLOB)
 598                 die("unable to read blob object %s", sha1_to_hex(sha1));
 599         mm->size = size;
 600 }
 601
 602 static int merge_3way(struct merge_options *o,
 603                       mmbuffer_t *result_buf,
 604                       struct diff_filespec *one,
 605                       struct diff_filespec *a,
 606                       struct diff_filespec *b,
 607                       const char *branch1,
 608                       const char *branch2)
 609 {
 610         mmfile_t orig, src1, src2;
 611         char *name1, *name2;
 612         int merge_status;
 613
 614         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 615         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 616
 617         fill_mm(one->sha1, &orig);
 618         fill_mm(a->sha1, &src1);
 619         fill_mm(b->sha1, &src2);
 620
 621         merge_status = ll_merge(result_buf, a->path, &orig,
 622                                 &src1, name1, &src2, name2,
 623                                 o->call_depth);
 624
 625         free(name1);
 626         free(name2);
 627         free(orig.ptr);
 628         free(src1.ptr);
 629         free(src2.ptr);
 630         return merge_status;
 631 }
 632
 633 static struct merge_file_info merge_file(struct merge_options *o,
 634                                          struct diff_filespec *one,
 635                                          struct diff_filespec *a,
 636                                          struct diff_filespec *b,
 637                                          const char *branch1,
 638                                          const char *branch2)
 639 {
 640         struct merge_file_info result;
 641         result.merge = 0;
 642         result.clean = 1;
 643
 644         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 645                 result.clean = 0;
 646                 if (S_ISREG(a->mode)) {
 647                         result.mode = a->mode;
 648                         hashcpy(result.sha, a->sha1);
 649                 } else {
 650                         result.mode = b->mode;
 651                         hashcpy(result.sha, b->sha1);
 652                 }
 653         } else {
 654                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 655                         result.merge = 1;
 656
 657                 /*
 658                  * Merge modes
 659                  */
 660                 if (a->mode == b->mode || a->mode == one->mode)
 661                         result.mode = b->mode;
 662                 else {
 663                         result.mode = a->mode;
 664                         if (b->mode != one->mode) {
 665                                 result.clean = 0;
 666                                 result.merge = 1;
 667                         }
 668                 }
 669
 670                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 671                         hashcpy(result.sha, b->sha1);
 672                 else if (sha_eq(b->sha1, one->sha1))
 673                         hashcpy(result.sha, a->sha1);
 674                 else if (S_ISREG(a->mode)) {
 675                         mmbuffer_t result_buf;
 676                         int merge_status;
 677
 678                         merge_status = merge_3way(o, &result_buf, one, a, b,
 679                                                   branch1, branch2);
 680
 681                         if ((merge_status < 0) || !result_buf.ptr)
 682                                 die("Failed to execute internal merge");
 683
 684                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 685                                             blob_type, result.sha))
 686                                 die("Unable to add %s to database",
 687                                     a->path);
 688
 689                         free(result_buf.ptr);
 690                         result.clean = (merge_status == 0);
 691                 } else if (S_ISGITLINK(a->mode)) {
 692                         result.clean = 0;
 693                         hashcpy(result.sha, a->sha1);
 694                 } else if (S_ISLNK(a->mode)) {
 695                         hashcpy(result.sha, a->sha1);
 696
 697                         if (!sha_eq(a->sha1, b->sha1))
 698                                 result.clean = 0;
 699                 } else {
 700                         die("unsupported object type in the tree");
 701                 }
 702         }
 703
 704         return result;
 705 }
 706
 707 static void conflict_rename_rename(struct merge_options *o,
 708                                    struct rename *ren1,
 709                                    const char *branch1,
 710                                    struct rename *ren2,
 711                                    const char *branch2)
 712 {
 713         char *del[2];
 714         int delp = 0;
 715         const char *ren1_dst = ren1->pair->two->path;
 716         const char *ren2_dst = ren2->pair->two->path;
 717         const char *dst_name1 = ren1_dst;
 718         const char *dst_name2 = ren2_dst;
 719         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 720                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 721                 output(o, 1, "%s is a directory in %s adding as %s instead",
 722                        ren1_dst, branch2, dst_name1);
 723                 remove_file(o, 0, ren1_dst, 0);
 724         }
 725         if (string_list_has_string(&current_directory_set, ren2_dst)) {
 726                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 727                 output(o, 1, "%s is a directory in %s adding as %s instead",
 728                        ren2_dst, branch1, dst_name2);
 729                 remove_file(o, 0, ren2_dst, 0);
 730         }
 731         if (o->call_depth) {
 732                 remove_file_from_cache(dst_name1);
 733                 remove_file_from_cache(dst_name2);
 734                 /*
 735                  * Uncomment to leave the conflicting names in the resulting tree
 736                  *
 737                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 738                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 739                  */
 740         } else {
 741                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 742                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 743         }
 744         while (delp--)
 745                 free(del[delp]);
 746 }
 747
 748 static void conflict_rename_dir(struct merge_options *o,
 749                                 struct rename *ren1,
 750                                 const char *branch1)
 751 {
 752         char *new_path = unique_path(ren1->pair->two->path, branch1);
 753         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 754         remove_file(o, 0, ren1->pair->two->path, 0);
 755         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 756         free(new_path);
 757 }
 758
 759 static void conflict_rename_rename_2(struct merge_options *o,
 760                                      struct rename *ren1,
 761                                      const char *branch1,
 762                                      struct rename *ren2,
 763                                      const char *branch2)
 764 {
 765         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 766         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 767         output(o, 1, "Renaming %s to %s and %s to %s instead",
 768                ren1->pair->one->path, new_path1,
 769                ren2->pair->one->path, new_path2);
 770         remove_file(o, 0, ren1->pair->two->path, 0);
 771         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 772         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 773         free(new_path2);
 774         free(new_path1);
 775 }
 776
 777 static int process_renames(struct merge_options *o,
 778                            struct string_list *a_renames,
 779                            struct string_list *b_renames)
 780 {
 781         int clean_merge = 1, i, j;
 782         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 783         const struct rename *sre;
 784
 785         for (i = 0; i < a_renames->nr; i++) {
 786                 sre = a_renames->items[i].util;
 787                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 788                         = sre->dst_entry;
 789         }
 790         for (i = 0; i < b_renames->nr; i++) {
 791                 sre = b_renames->items[i].util;
 792                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 793                         = sre->dst_entry;
 794         }
 795
 796         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 797                 int compare;
 798                 char *src;
 799                 struct string_list *renames1, *renames2, *renames2Dst;
 800                 struct rename *ren1 = NULL, *ren2 = NULL;
 801                 const char *branch1, *branch2;
 802                 const char *ren1_src, *ren1_dst;
 803
 804                 if (i >= a_renames->nr) {
 805                         compare = 1;
 806                         ren2 = b_renames->items[j++].util;
 807                 } else if (j >= b_renames->nr) {
 808                         compare = -1;
 809                         ren1 = a_renames->items[i++].util;
 810                 } else {
 811                         compare = strcmp(a_renames->items[i].string,
 812                                         b_renames->items[j].string);
 813                         if (compare <= 0)
 814                                 ren1 = a_renames->items[i++].util;
 815                         if (compare >= 0)
 816                                 ren2 = b_renames->items[j++].util;
 817                 }
 818
 819                 /* TODO: refactor, so that 1/2 are not needed */
 820                 if (ren1) {
 821                         renames1 = a_renames;
 822                         renames2 = b_renames;
 823                         renames2Dst = &b_by_dst;
 824                         branch1 = o->branch1;
 825                         branch2 = o->branch2;
 826                 } else {
 827                         struct rename *tmp;
 828                         renames1 = b_renames;
 829                         renames2 = a_renames;
 830                         renames2Dst = &a_by_dst;
 831                         branch1 = o->branch2;
 832                         branch2 = o->branch1;
 833                         tmp = ren2;
 834                         ren2 = ren1;
 835                         ren1 = tmp;
 836                 }
 837                 src = ren1->pair->one->path;
 838
 839                 ren1->dst_entry->processed = 1;
 840                 ren1->src_entry->processed = 1;
 841
 842                 if (ren1->processed)
 843                         continue;
 844                 ren1->processed = 1;
 845
 846                 ren1_src = ren1->pair->one->path;
 847                 ren1_dst = ren1->pair->two->path;
 848
 849                 if (ren2) {
 850                         const char *ren2_src = ren2->pair->one->path;
 851                         const char *ren2_dst = ren2->pair->two->path;
 852                         /* Renamed in 1 and renamed in 2 */
 853                         if (strcmp(ren1_src, ren2_src) != 0)
 854                                 die("ren1.src != ren2.src");
 855                         ren2->dst_entry->processed = 1;
 856                         ren2->processed = 1;
 857                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 858                                 clean_merge = 0;
 859                                 output(o, 1, "CONFLICT (rename/rename): "
 860                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 861                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 862                                        src, ren1_dst, branch1,
 863                                        src, ren2_dst, branch2,
 864                                        o->call_depth ? " (left unresolved)": "");
 865                                 if (o->call_depth) {
 866                                         remove_file_from_cache(src);
 867                                         update_file(o, 0, ren1->pair->one->sha1,
 868                                                     ren1->pair->one->mode, src);
 869                                 }
 870                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 871                         } else {
 872                                 struct merge_file_info mfi;
 873                                 remove_file(o, 1, ren1_src, 1);
 874                                 mfi = merge_file(o,
 875                                                  ren1->pair->one,
 876                                                  ren1->pair->two,
 877                                                  ren2->pair->two,
 878                                                  branch1,
 879                                                  branch2);
 880                                 if (mfi.merge || !mfi.clean)
 881                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 882
 883                                 if (mfi.merge)
 884                                         output(o, 2, "Auto-merging %s", ren1_dst);
 885
 886                                 if (!mfi.clean) {
 887                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 888                                                ren1_dst);
 889                                         clean_merge = 0;
 890
 891                                         if (!o->call_depth)
 892                                                 update_stages(ren1_dst,
 893                                                               ren1->pair->one,
 894                                                               ren1->pair->two,
 895                                                               ren2->pair->two,
 896                                                               1 /* clear */);
 897                                 }
 898                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 899                         }
 900                 } else {
 901                         /* Renamed in 1, maybe changed in 2 */
 902                         struct string_list_item *item;
 903                         /* we only use sha1 and mode of these */
 904                         struct diff_filespec src_other, dst_other;
 905                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 906
 907                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 908
 909                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 910                         src_other.mode = ren1->src_entry->stages[stage].mode;
 911                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 912                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 913
 914                         try_merge = 0;
 915
 916                         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 917                                 clean_merge = 0;
 918                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 919                                        " directory %s added in %s",
 920                                        ren1_src, ren1_dst, branch1,
 921                                        ren1_dst, branch2);
 922                                 conflict_rename_dir(o, ren1, branch1);
 923                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 924                                 clean_merge = 0;
 925                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 926                                        "and deleted in %s",
 927                                        ren1_src, ren1_dst, branch1,
 928                                        branch2);
 929                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 930                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 931                                 const char *new_path;
 932                                 clean_merge = 0;
 933                                 try_merge = 1;
 934                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 935                                        "%s added in %s",
 936                                        ren1_src, ren1_dst, branch1,
 937                                        ren1_dst, branch2);
 938                                 new_path = unique_path(ren1_dst, branch2);
 939                                 output(o, 1, "Adding as %s instead", new_path);
 940                                 update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 941                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 942                                 ren2 = item->util;
 943                                 clean_merge = 0;
 944                                 ren2->processed = 1;
 945                                 output(o, 1, "CONFLICT (rename/rename): "
 946                                        "Rename %s->%s in %s. "
 947                                        "Rename %s->%s in %s",
 948                                        ren1_src, ren1_dst, branch1,
 949                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 950                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
 951                         } else
 952                                 try_merge = 1;
 953
 954                         if (try_merge) {
 955                                 struct diff_filespec *one, *a, *b;
 956                                 struct merge_file_info mfi;
 957                                 src_other.path = (char *)ren1_src;
 958
 959                                 one = ren1->pair->one;
 960                                 if (a_renames == renames1) {
 961                                         a = ren1->pair->two;
 962                                         b = &src_other;
 963                                 } else {
 964                                         b = ren1->pair->two;
 965                                         a = &src_other;
 966                                 }
 967                                 mfi = merge_file(o, one, a, b,
 968                                                 o->branch1, o->branch2);
 969
 970                                 if (mfi.clean &&
 971                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
 972                                     mfi.mode == ren1->pair->two->mode)
 973                                         /*
 974                                          * This messaged is part of
 975                                          * t6022 test. If you change
 976                                          * it update the test too.
 977                                          */
 978                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
 979                                 else {
 980                                         if (mfi.merge || !mfi.clean)
 981                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
 982                                         if (mfi.merge)
 983                                                 output(o, 2, "Auto-merging %s", ren1_dst);
 984                                         if (!mfi.clean) {
 985                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
 986                                                        ren1_dst);
 987                                                 clean_merge = 0;
 988
 989                                                 if (!o->call_depth)
 990                                                         update_stages(ren1_dst,
 991                                                                       one, a, b, 1);
 992                                         }
 993                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 994                                 }
 995                         }
 996                 }
 997         }
 998         string_list_clear(&a_by_dst, 0);
 999         string_list_clear(&b_by_dst, 0);
1000
1001         return clean_merge;
1002 }
1003
1004 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1005 {
1006         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1007 }
1008
1009 /* Per entry merge function */
1010 static int process_entry(struct merge_options *o,
1011                          const char *path, struct stage_data *entry)
1012 {
1013         /*
1014         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1015         print_index_entry("\tpath: ", entry);
1016         */
1017         int clean_merge = 1;
1018         unsigned o_mode = entry->stages[1].mode;
1019         unsigned a_mode = entry->stages[2].mode;
1020         unsigned b_mode = entry->stages[3].mode;
1021         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1022         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1023         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1024
1025         if (o_sha && (!a_sha || !b_sha)) {
1026                 /* Case A: Deleted in one */
1027                 if ((!a_sha && !b_sha) ||
1028                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1029                     (!a_sha && sha_eq(b_sha, o_sha))) {
1030                         /* Deleted in both or deleted in one and
1031                          * unchanged in the other */
1032                         if (a_sha)
1033                                 output(o, 2, "Removing %s", path);
1034                         /* do not touch working file if it did not exist */
1035                         remove_file(o, 1, path, !a_sha);
1036                 } else {
1037                         /* Deleted in one and changed in the other */
1038                         clean_merge = 0;
1039                         if (!a_sha) {
1040                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1041                                        "and modified in %s. Version %s of %s left in tree.",
1042                                        path, o->branch1,
1043                                        o->branch2, o->branch2, path);
1044                                 update_file(o, 0, b_sha, b_mode, path);
1045                         } else {
1046                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1047                                        "and modified in %s. Version %s of %s left in tree.",
1048                                        path, o->branch2,
1049                                        o->branch1, o->branch1, path);
1050                                 update_file(o, 0, a_sha, a_mode, path);
1051                         }
1052                 }
1053
1054         } else if ((!o_sha && a_sha && !b_sha) ||
1055                    (!o_sha && !a_sha && b_sha)) {
1056                 /* Case B: Added in one. */
1057                 const char *add_branch;
1058                 const char *other_branch;
1059                 unsigned mode;
1060                 const unsigned char *sha;
1061                 const char *conf;
1062
1063                 if (a_sha) {
1064                         add_branch = o->branch1;
1065                         other_branch = o->branch2;
1066                         mode = a_mode;
1067                         sha = a_sha;
1068                         conf = "file/directory";
1069                 } else {
1070                         add_branch = o->branch2;
1071                         other_branch = o->branch1;
1072                         mode = b_mode;
1073                         sha = b_sha;
1074                         conf = "directory/file";
1075                 }
1076                 if (string_list_has_string(&current_directory_set, path)) {
1077                         const char *new_path = unique_path(path, add_branch);
1078                         clean_merge = 0;
1079                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1080                                "Adding %s as %s",
1081                                conf, path, other_branch, path, new_path);
1082                         remove_file(o, 0, path, 0);
1083                         update_file(o, 0, sha, mode, new_path);
1084                 } else {
1085                         output(o, 2, "Adding %s", path);
1086                         update_file(o, 1, sha, mode, path);
1087                 }
1088         } else if (a_sha && b_sha) {
1089                 /* Case C: Added in both (check for same permissions) and */
1090                 /* case D: Modified in both, but differently. */
1091                 const char *reason = "content";
1092                 struct merge_file_info mfi;
1093                 struct diff_filespec one, a, b;
1094
1095                 if (!o_sha) {
1096                         reason = "add/add";
1097                         o_sha = (unsigned char *)null_sha1;
1098                 }
1099                 output(o, 2, "Auto-merging %s", path);
1100                 one.path = a.path = b.path = (char *)path;
1101                 hashcpy(one.sha1, o_sha);
1102                 one.mode = o_mode;
1103                 hashcpy(a.sha1, a_sha);
1104                 a.mode = a_mode;
1105                 hashcpy(b.sha1, b_sha);
1106                 b.mode = b_mode;
1107
1108                 mfi = merge_file(o, &one, &a, &b,
1109                                  o->branch1, o->branch2);
1110
1111                 clean_merge = mfi.clean;
1112                 if (mfi.clean)
1113                         update_file(o, 1, mfi.sha, mfi.mode, path);
1114                 else if (S_ISGITLINK(mfi.mode))
1115                         output(o, 1, "CONFLICT (submodule): Merge conflict in %s "
1116                                "- needs %s", path, sha1_to_hex(b.sha1));
1117                 else {
1118                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1119                                         reason, path);
1120
1121                         if (o->call_depth)
1122                                 update_file(o, 0, mfi.sha, mfi.mode, path);
1123                         else
1124                                 update_file_flags(o, mfi.sha, mfi.mode, path,
1125                                               0 /* update_cache */, 1 /* update_working_directory */);
1126                 }
1127         } else if (!o_sha && !a_sha && !b_sha) {
1128                 /*
1129                  * this entry was deleted altogether. a_mode == 0 means
1130                  * we had that path and want to actively remove it.
1131                  */
1132                 remove_file(o, 1, path, !a_mode);
1133         } else
1134                 die("Fatal merge failure, shouldn't happen.");
1135
1136         return clean_merge;
1137 }
1138
1139 int merge_trees(struct merge_options *o,
1140                 struct tree *head,
1141                 struct tree *merge,
1142                 struct tree *common,
1143                 struct tree **result)
1144 {
1145         int code, clean;
1146
1147         if (o->subtree_merge) {
1148                 merge = shift_tree_object(head, merge);
1149                 common = shift_tree_object(head, common);
1150         }
1151
1152         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1153                 output(o, 0, "Already uptodate!");
1154                 *result = head;
1155                 return 1;
1156         }
1157
1158         code = git_merge_trees(o->call_depth, common, head, merge);
1159
1160         if (code != 0)
1161                 die("merging of trees %s and %s failed",
1162                     sha1_to_hex(head->object.sha1),
1163                     sha1_to_hex(merge->object.sha1));
1164
1165         if (unmerged_cache()) {
1166                 struct string_list *entries, *re_head, *re_merge;
1167                 int i;
1168                 string_list_clear(&current_file_set, 1);
1169                 string_list_clear(&current_directory_set, 1);
1170                 get_files_dirs(head);
1171                 get_files_dirs(merge);
1172
1173                 entries = get_unmerged();
1174                 re_head  = get_renames(o, head, common, head, merge, entries);
1175                 re_merge = get_renames(o, merge, common, head, merge, entries);
1176                 clean = process_renames(o, re_head, re_merge);
1177                 for (i = 0; i < entries->nr; i++) {
1178                         const char *path = entries->items[i].string;
1179                         struct stage_data *e = entries->items[i].util;
1180                         if (!e->processed
1181                                 && !process_entry(o, path, e))
1182                                 clean = 0;
1183                 }
1184
1185                 string_list_clear(re_merge, 0);
1186                 string_list_clear(re_head, 0);
1187                 string_list_clear(entries, 1);
1188
1189         }
1190         else
1191                 clean = 1;
1192
1193         if (o->call_depth)
1194                 *result = write_tree_from_memory(o);
1195
1196         return clean;
1197 }
1198
1199 static struct commit_list *reverse_commit_list(struct commit_list *list)
1200 {
1201         struct commit_list *next = NULL, *current, *backup;
1202         for (current = list; current; current = backup) {
1203                 backup = current->next;
1204                 current->next = next;
1205                 next = current;
1206         }
1207         return next;
1208 }
1209
1210 /*
1211  * Merge the commits h1 and h2, return the resulting virtual
1212  * commit object and a flag indicating the cleanness of the merge.
1213  */
1214 int merge_recursive(struct merge_options *o,
1215                     struct commit *h1,
1216                     struct commit *h2,
1217                     struct commit_list *ca,
1218                     struct commit **result)
1219 {
1220         struct commit_list *iter;
1221         struct commit *merged_common_ancestors;
1222         struct tree *mrtree = mrtree;
1223         int clean;
1224
1225         if (show(o, 4)) {
1226                 output(o, 4, "Merging:");
1227                 output_commit_title(o, h1);
1228                 output_commit_title(o, h2);
1229         }
1230
1231         if (!ca) {
1232                 ca = get_merge_bases(h1, h2, 1);
1233                 ca = reverse_commit_list(ca);
1234         }
1235
1236         if (show(o, 5)) {
1237                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1238                 for (iter = ca; iter; iter = iter->next)
1239                         output_commit_title(o, iter->item);
1240         }
1241
1242         merged_common_ancestors = pop_commit(&ca);
1243         if (merged_common_ancestors == NULL) {
1244                 /* if there is no common ancestor, make an empty tree */
1245                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1246
1247                 tree->object.parsed = 1;
1248                 tree->object.type = OBJ_TREE;
1249                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1250                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1251         }
1252
1253         for (iter = ca; iter; iter = iter->next) {
1254                 const char *saved_b1, *saved_b2;
1255                 o->call_depth++;
1256                 /*
1257                  * When the merge fails, the result contains files
1258                  * with conflict markers. The cleanness flag is
1259                  * ignored, it was never actually used, as result of
1260                  * merge_trees has always overwritten it: the committed
1261                  * "conflicts" were already resolved.
1262                  */
1263                 discard_cache();
1264                 saved_b1 = o->branch1;
1265                 saved_b2 = o->branch2;
1266                 o->branch1 = "Temporary merge branch 1";
1267                 o->branch2 = "Temporary merge branch 2";
1268                 merge_recursive(o, merged_common_ancestors, iter->item,
1269                                 NULL, &merged_common_ancestors);
1270                 o->branch1 = saved_b1;
1271                 o->branch2 = saved_b2;
1272                 o->call_depth--;
1273
1274                 if (!merged_common_ancestors)
1275                         die("merge returned no commit");
1276         }
1277
1278         discard_cache();
1279         if (!o->call_depth)
1280                 read_cache();
1281
1282         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1283                             &mrtree);
1284
1285         if (o->call_depth) {
1286                 *result = make_virtual_commit(mrtree, "merged tree");
1287                 commit_list_insert(h1, &(*result)->parents);
1288                 commit_list_insert(h2, &(*result)->parents->next);
1289         }
1290         flush_output(o);
1291         return clean;
1292 }
1293
1294 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1295 {
1296         struct object *object;
1297
1298         object = deref_tag(parse_object(sha1), name, strlen(name));
1299         if (!object)
1300                 return NULL;
1301         if (object->type == OBJ_TREE)
1302                 return make_virtual_commit((struct tree*)object, name);
1303         if (object->type != OBJ_COMMIT)
1304                 return NULL;
1305         if (parse_commit((struct commit *)object))
1306                 return NULL;
1307         return (struct commit *)object;
1308 }
1309
1310 int merge_recursive_generic(struct merge_options *o,
1311                             const unsigned char *head,
1312                             const unsigned char *merge,
1313                             int num_base_list,
1314                             const unsigned char **base_list,
1315                             struct commit **result)
1316 {
1317         int clean, index_fd;
1318         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1319         struct commit *head_commit = get_ref(head, o->branch1);
1320         struct commit *next_commit = get_ref(merge, o->branch2);
1321         struct commit_list *ca = NULL;
1322
1323         if (base_list) {
1324                 int i;
1325                 for (i = 0; i < num_base_list; ++i) {
1326                         struct commit *base;
1327                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1328                                 return error("Could not parse object '%s'",
1329                                         sha1_to_hex(base_list[i]));
1330                         commit_list_insert(base, &ca);
1331                 }
1332         }
1333
1334         index_fd = hold_locked_index(lock, 1);
1335         clean = merge_recursive(o, head_commit, next_commit, ca,
1336                         result);
1337         if (active_cache_changed &&
1338                         (write_cache(index_fd, active_cache, active_nr) ||
1339                          commit_locked_index(lock)))
1340                 return error("Unable to write index.");
1341
1342         return clean ? 0 : 1;
1343 }
1344
1345 static int merge_recursive_config(const char *var, const char *value, void *cb)
1346 {
1347         struct merge_options *o = cb;
1348         if (!strcasecmp(var, "merge.verbosity")) {
1349                 o->verbosity = git_config_int(var, value);
1350                 return 0;
1351         }
1352         if (!strcasecmp(var, "diff.renamelimit")) {
1353                 o->diff_rename_limit = git_config_int(var, value);
1354                 return 0;
1355         }
1356         if (!strcasecmp(var, "merge.renamelimit")) {
1357                 o->merge_rename_limit = git_config_int(var, value);
1358                 return 0;
1359         }
1360         return git_default_config(var, value, cb);
1361 }
1362
1363 void init_merge_options(struct merge_options *o)
1364 {
1365         memset(o, 0, sizeof(struct merge_options));
1366         o->verbosity = 2;
1367         o->buffer_output = 1;
1368         o->diff_rename_limit = -1;
1369         o->merge_rename_limit = -1;
1370         git_config(merge_recursive_config, o);
1371         if (getenv("GIT_MERGE_VERBOSITY"))
1372                 o->verbosity =
1373                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1374         if (o->verbosity >= 5)
1375                 o->buffer_output = 0;
1376         strbuf_init(&o->obuf, 0);
1377 }