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

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