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
  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 struct strbuf obuf = STRBUF_INIT;
  84
  85 static int show(struct merge_options *o, int v)
  86 {
  87         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  88 }
  89
  90 static void flush_output(void)
  91 {
  92         if (obuf.len) {
  93                 fputs(obuf.buf, stdout);
  94                 strbuf_reset(&obuf);
  95         }
  96 }
  97
  98 static void output(struct merge_options *o, int v, const char *fmt, ...)
  99 {
 100         int len;
 101         va_list ap;
 102
 103         if (!show(o, v))
 104                 return;
 105
 106         strbuf_grow(&obuf, o->call_depth * 2 + 2);
 107         memset(obuf.buf + obuf.len, ' ', o->call_depth * 2);
 108         strbuf_setlen(&obuf, obuf.len + o->call_depth * 2);
 109
 110         va_start(ap, fmt);
 111         len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 112         va_end(ap);
 113
 114         if (len < 0)
 115                 len = 0;
 116         if (len >= strbuf_avail(&obuf)) {
 117                 strbuf_grow(&obuf, len + 2);
 118                 va_start(ap, fmt);
 119                 len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 120                 va_end(ap);
 121                 if (len >= strbuf_avail(&obuf)) {
 122                         die("this should not happen, your snprintf is broken");
 123                 }
 124         }
 125         strbuf_setlen(&obuf, obuf.len + len);
 126         strbuf_add(&obuf, "\n", 1);
 127         if (!o->buffer_output)
 128                 flush_output();
 129 }
 130
 131 static void output_commit_title(struct merge_options *o, struct commit *commit)
 132 {
 133         int i;
 134         flush_output();
 135         for (i = o->call_depth; i--;)
 136                 fputs("  ", stdout);
 137         if (commit->util)
 138                 printf("virtual %s\n", (char *)commit->util);
 139         else {
 140                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 141                 if (parse_commit(commit) != 0)
 142                         printf("(bad commit)\n");
 143                 else {
 144                         const char *s;
 145                         int len;
 146                         for (s = commit->buffer; *s; s++)
 147                                 if (*s == '\n' && s[1] == '\n') {
 148                                         s += 2;
 149                                         break;
 150                                 }
 151                         for (len = 0; s[len] && '\n' != s[len]; len++)
 152                                 ; /* do nothing */
 153                         printf("%.*s\n", len, s);
 154                 }
 155         }
 156 }
 157
 158 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 159                 const char *path, int stage, int refresh, int options)
 160 {
 161         struct cache_entry *ce;
 162         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 163         if (!ce)
 164                 return error("addinfo_cache failed for path '%s'", path);
 165         return add_cache_entry(ce, options);
 166 }
 167
 168 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 169 {
 170         parse_tree(tree);
 171         init_tree_desc(desc, tree->buffer, tree->size);
 172 }
 173
 174 static int git_merge_trees(int index_only,
 175                            struct tree *common,
 176                            struct tree *head,
 177                            struct tree *merge)
 178 {
 179         int rc;
 180         struct tree_desc t[3];
 181         struct unpack_trees_options opts;
 182
 183         memset(&opts, 0, sizeof(opts));
 184         if (index_only)
 185                 opts.index_only = 1;
 186         else
 187                 opts.update = 1;
 188         opts.merge = 1;
 189         opts.head_idx = 2;
 190         opts.fn = threeway_merge;
 191         opts.src_index = &the_index;
 192         opts.dst_index = &the_index;
 193
 194         init_tree_desc_from_tree(t+0, common);
 195         init_tree_desc_from_tree(t+1, head);
 196         init_tree_desc_from_tree(t+2, merge);
 197
 198         rc = unpack_trees(3, t, &opts);
 199         cache_tree_free(&active_cache_tree);
 200         return rc;
 201 }
 202
 203 struct tree *write_tree_from_memory(struct merge_options *o)
 204 {
 205         struct tree *result = NULL;
 206
 207         if (unmerged_cache()) {
 208                 int i;
 209                 output(o, 0, "There are unmerged index entries:");
 210                 for (i = 0; i < active_nr; i++) {
 211                         struct cache_entry *ce = active_cache[i];
 212                         if (ce_stage(ce))
 213                                 output(o, 0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 214                 }
 215                 return NULL;
 216         }
 217
 218         if (!active_cache_tree)
 219                 active_cache_tree = cache_tree();
 220
 221         if (!cache_tree_fully_valid(active_cache_tree) &&
 222             cache_tree_update(active_cache_tree,
 223                               active_cache, active_nr, 0, 0) < 0)
 224                 die("error building trees");
 225
 226         result = lookup_tree(active_cache_tree->sha1);
 227
 228         return result;
 229 }
 230
 231 static int save_files_dirs(const unsigned char *sha1,
 232                 const char *base, int baselen, const char *path,
 233                 unsigned int mode, int stage, void *context)
 234 {
 235         int len = strlen(path);
 236         char *newpath = xmalloc(baselen + len + 1);
 237         memcpy(newpath, base, baselen);
 238         memcpy(newpath + baselen, path, len);
 239         newpath[baselen + len] = '\0';
 240
 241         if (S_ISDIR(mode))
 242                 string_list_insert(newpath, &current_directory_set);
 243         else
 244                 string_list_insert(newpath, &current_file_set);
 245         free(newpath);
 246
 247         return READ_TREE_RECURSIVE;
 248 }
 249
 250 static int get_files_dirs(struct tree *tree)
 251 {
 252         int n;
 253         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, NULL))
 254                 return 0;
 255         n = current_file_set.nr + current_directory_set.nr;
 256         return n;
 257 }
 258
 259 /*
 260  * Returns an index_entry instance which doesn't have to correspond to
 261  * a real cache entry in Git's index.
 262  */
 263 static struct stage_data *insert_stage_data(const char *path,
 264                 struct tree *o, struct tree *a, struct tree *b,
 265                 struct string_list *entries)
 266 {
 267         struct string_list_item *item;
 268         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 269         get_tree_entry(o->object.sha1, path,
 270                         e->stages[1].sha, &e->stages[1].mode);
 271         get_tree_entry(a->object.sha1, path,
 272                         e->stages[2].sha, &e->stages[2].mode);
 273         get_tree_entry(b->object.sha1, path,
 274                         e->stages[3].sha, &e->stages[3].mode);
 275         item = string_list_insert(path, entries);
 276         item->util = e;
 277         return e;
 278 }
 279
 280 /*
 281  * Create a dictionary mapping file names to stage_data objects. The
 282  * dictionary contains one entry for every path with a non-zero stage entry.
 283  */
 284 static struct string_list *get_unmerged(void)
 285 {
 286         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 287         int i;
 288
 289         unmerged->strdup_strings = 1;
 290
 291         for (i = 0; i < active_nr; i++) {
 292                 struct string_list_item *item;
 293                 struct stage_data *e;
 294                 struct cache_entry *ce = active_cache[i];
 295                 if (!ce_stage(ce))
 296                         continue;
 297
 298                 item = string_list_lookup(ce->name, unmerged);
 299                 if (!item) {
 300                         item = string_list_insert(ce->name, unmerged);
 301                         item->util = xcalloc(1, sizeof(struct stage_data));
 302                 }
 303                 e = item->util;
 304                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 305                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 306         }
 307
 308         return unmerged;
 309 }
 310
 311 struct rename
 312 {
 313         struct diff_filepair *pair;
 314         struct stage_data *src_entry;
 315         struct stage_data *dst_entry;
 316         unsigned processed:1;
 317 };
 318
 319 /*
 320  * Get information of all renames which occurred between 'o_tree' and
 321  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 322  * 'b_tree') to be able to associate the correct cache entries with
 323  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 324  */
 325 static struct string_list *get_renames(struct merge_options *o,
 326                                        struct tree *tree,
 327                                        struct tree *o_tree,
 328                                        struct tree *a_tree,
 329                                        struct tree *b_tree,
 330                                        struct string_list *entries)
 331 {
 332         int i;
 333         struct string_list *renames;
 334         struct diff_options opts;
 335
 336         renames = xcalloc(1, sizeof(struct string_list));
 337         diff_setup(&opts);
 338         DIFF_OPT_SET(&opts, RECURSIVE);
 339         opts.detect_rename = DIFF_DETECT_RENAME;
 340         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 341                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 342                             500;
 343         opts.warn_on_too_large_rename = 1;
 344         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 345         if (diff_setup_done(&opts) < 0)
 346                 die("diff setup failed");
 347         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 348         diffcore_std(&opts);
 349         for (i = 0; i < diff_queued_diff.nr; ++i) {
 350                 struct string_list_item *item;
 351                 struct rename *re;
 352                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 353                 if (pair->status != 'R') {
 354                         diff_free_filepair(pair);
 355                         continue;
 356                 }
 357                 re = xmalloc(sizeof(*re));
 358                 re->processed = 0;
 359                 re->pair = pair;
 360                 item = string_list_lookup(re->pair->one->path, entries);
 361                 if (!item)
 362                         re->src_entry = insert_stage_data(re->pair->one->path,
 363                                         o_tree, a_tree, b_tree, entries);
 364                 else
 365                         re->src_entry = item->util;
 366
 367                 item = string_list_lookup(re->pair->two->path, entries);
 368                 if (!item)
 369                         re->dst_entry = insert_stage_data(re->pair->two->path,
 370                                         o_tree, a_tree, b_tree, entries);
 371                 else
 372                         re->dst_entry = item->util;
 373                 item = string_list_insert(pair->one->path, renames);
 374                 item->util = re;
 375         }
 376         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 377         diff_queued_diff.nr = 0;
 378         diff_flush(&opts);
 379         return renames;
 380 }
 381
 382 static int update_stages(const char *path, struct diff_filespec *o,
 383                          struct diff_filespec *a, struct diff_filespec *b,
 384                          int clear)
 385 {
 386         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 387         if (clear)
 388                 if (remove_file_from_cache(path))
 389                         return -1;
 390         if (o)
 391                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 392                         return -1;
 393         if (a)
 394                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 395                         return -1;
 396         if (b)
 397                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 398                         return -1;
 399         return 0;
 400 }
 401
 402 static int remove_path(const char *name)
 403 {
 404         int ret;
 405         char *slash, *dirs;
 406
 407         ret = unlink(name);
 408         if (ret)
 409                 return ret;
 410         dirs = xstrdup(name);
 411         while ((slash = strrchr(name, '/'))) {
 412                 *slash = '\0';
 413                 if (rmdir(name) != 0)
 414                         break;
 415         }
 416         free(dirs);
 417         return ret;
 418 }
 419
 420 static int remove_file(struct merge_options *o, int clean,
 421                        const char *path, int no_wd)
 422 {
 423         int update_cache = o->call_depth || clean;
 424         int update_working_directory = !o->call_depth && !no_wd;
 425
 426         if (update_cache) {
 427                 if (remove_file_from_cache(path))
 428                         return -1;
 429         }
 430         if (update_working_directory) {
 431                 unlink(path);
 432                 if (errno != ENOENT || errno != EISDIR)
 433                         return -1;
 434                 remove_path(path);
 435         }
 436         return 0;
 437 }
 438
 439 static char *unique_path(const char *path, const char *branch)
 440 {
 441         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 442         int suffix = 0;
 443         struct stat st;
 444         char *p = newpath + strlen(path);
 445         strcpy(newpath, path);
 446         *(p++) = '~';
 447         strcpy(p, branch);
 448         for (; *p; ++p)
 449                 if ('/' == *p)
 450                         *p = '_';
 451         while (string_list_has_string(&current_file_set, newpath) ||
 452                string_list_has_string(&current_directory_set, newpath) ||
 453                lstat(newpath, &st) == 0)
 454                 sprintf(p, "_%d", suffix++);
 455
 456         string_list_insert(newpath, &current_file_set);
 457         return newpath;
 458 }
 459
 460 static void flush_buffer(int fd, const char *buf, unsigned long size)
 461 {
 462         while (size > 0) {
 463                 long ret = write_in_full(fd, buf, size);
 464                 if (ret < 0) {
 465                         /* Ignore epipe */
 466                         if (errno == EPIPE)
 467                                 break;
 468                         die("merge-recursive: %s", strerror(errno));
 469                 } else if (!ret) {
 470                         die("merge-recursive: disk full?");
 471                 }
 472                 size -= ret;
 473                 buf += ret;
 474         }
 475 }
 476
 477 static int make_room_for_path(const char *path)
 478 {
 479         int status;
 480         const char *msg = "failed to create path '%s'%s";
 481
 482         status = safe_create_leading_directories_const(path);
 483         if (status) {
 484                 if (status == -3) {
 485                         /* something else exists */
 486                         error(msg, path, ": perhaps a D/F conflict?");
 487                         return -1;
 488                 }
 489                 die(msg, path, "");
 490         }
 491
 492         /* Successful unlink is good.. */
 493         if (!unlink(path))
 494                 return 0;
 495         /* .. and so is no existing file */
 496         if (errno == ENOENT)
 497                 return 0;
 498         /* .. but not some other error (who really cares what?) */
 499         return error(msg, path, ": perhaps a D/F conflict?");
 500 }
 501
 502 static void update_file_flags(struct merge_options *o,
 503                               const unsigned char *sha,
 504                               unsigned mode,
 505                               const char *path,
 506                               int update_cache,
 507                               int update_wd)
 508 {
 509         if (o->call_depth)
 510                 update_wd = 0;
 511
 512         if (update_wd) {
 513                 enum object_type type;
 514                 void *buf;
 515                 unsigned long size;
 516
 517                 if (S_ISGITLINK(mode))
 518                         die("cannot read object %s '%s': It is a submodule!",
 519                             sha1_to_hex(sha), path);
 520
 521                 buf = read_sha1_file(sha, &type, &size);
 522                 if (!buf)
 523                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 524                 if (type != OBJ_BLOB)
 525                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 526                 if (S_ISREG(mode)) {
 527                         struct strbuf strbuf;
 528                         strbuf_init(&strbuf, 0);
 529                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 530                                 free(buf);
 531                                 size = strbuf.len;
 532                                 buf = strbuf_detach(&strbuf, NULL);
 533                         }
 534                 }
 535
 536                 if (make_room_for_path(path) < 0) {
 537                         update_wd = 0;
 538                         free(buf);
 539                         goto update_index;
 540                 }
 541                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 542                         int fd;
 543                         if (mode & 0100)
 544                                 mode = 0777;
 545                         else
 546                                 mode = 0666;
 547                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 548                         if (fd < 0)
 549                                 die("failed to open %s: %s", path, strerror(errno));
 550                         flush_buffer(fd, buf, size);
 551                         close(fd);
 552                 } else if (S_ISLNK(mode)) {
 553                         char *lnk = xmemdupz(buf, size);
 554                         safe_create_leading_directories_const(path);
 555                         unlink(path);
 556                         symlink(lnk, path);
 557                         free(lnk);
 558                 } else
 559                         die("do not know what to do with %06o %s '%s'",
 560                             mode, sha1_to_hex(sha), path);
 561                 free(buf);
 562         }
 563  update_index:
 564         if (update_cache)
 565                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 566 }
 567
 568 static void update_file(struct merge_options *o,
 569                         int clean,
 570                         const unsigned char *sha,
 571                         unsigned mode,
 572                         const char *path)
 573 {
 574         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 575 }
 576
 577 /* Low level file merging, update and removal */
 578
 579 struct merge_file_info
 580 {
 581         unsigned char sha[20];
 582         unsigned mode;
 583         unsigned clean:1,
 584                  merge:1;
 585 };
 586
 587 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 588 {
 589         unsigned long size;
 590         enum object_type type;
 591
 592         if (!hashcmp(sha1, null_sha1)) {
 593                 mm->ptr = xstrdup("");
 594                 mm->size = 0;
 595                 return;
 596         }
 597
 598         mm->ptr = read_sha1_file(sha1, &type, &size);
 599         if (!mm->ptr || type != OBJ_BLOB)
 600                 die("unable to read blob object %s", sha1_to_hex(sha1));
 601         mm->size = size;
 602 }
 603
 604 static int merge_3way(struct merge_options *o,
 605                       mmbuffer_t *result_buf,
 606                       struct diff_filespec *one,
 607                       struct diff_filespec *a,
 608                       struct diff_filespec *b,
 609                       const char *branch1,
 610                       const char *branch2)
 611 {
 612         mmfile_t orig, src1, src2;
 613         char *name1, *name2;
 614         int merge_status;
 615
 616         name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 617         name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 618
 619         fill_mm(one->sha1, &orig);
 620         fill_mm(a->sha1, &src1);
 621         fill_mm(b->sha1, &src2);
 622
 623         merge_status = ll_merge(result_buf, a->path, &orig,
 624                                 &src1, name1, &src2, name2,
 625                                 o->call_depth);
 626
 627         free(name1);
 628         free(name2);
 629         free(orig.ptr);
 630         free(src1.ptr);
 631         free(src2.ptr);
 632         return merge_status;
 633 }
 634
 635 static struct merge_file_info merge_file(struct merge_options *o,
 636                                          struct diff_filespec *one,
 637                                          struct diff_filespec *a,
 638                                          struct diff_filespec *b,
 639                                          const char *branch1,
 640                                          const char *branch2)
 641 {
 642         struct merge_file_info result;
 643         result.merge = 0;
 644         result.clean = 1;
 645
 646         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 647                 result.clean = 0;
 648                 if (S_ISREG(a->mode)) {
 649                         result.mode = a->mode;
 650                         hashcpy(result.sha, a->sha1);
 651                 } else {
 652                         result.mode = b->mode;
 653                         hashcpy(result.sha, b->sha1);
 654                 }
 655         } else {
 656                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 657                         result.merge = 1;
 658
 659                 /*
 660                  * Merge modes
 661                  */
 662                 if (a->mode == b->mode || a->mode == one->mode)
 663                         result.mode = b->mode;
 664                 else {
 665                         result.mode = a->mode;
 666                         if (b->mode != one->mode) {
 667                                 result.clean = 0;
 668                                 result.merge = 1;
 669                         }
 670                 }
 671
 672                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 673                         hashcpy(result.sha, b->sha1);
 674                 else if (sha_eq(b->sha1, one->sha1))
 675                         hashcpy(result.sha, a->sha1);
 676                 else if (S_ISREG(a->mode)) {
 677                         mmbuffer_t result_buf;
 678                         int merge_status;
 679
 680                         merge_status = merge_3way(o, &result_buf, one, a, b,
 681                                                   branch1, branch2);
 682
 683                         if ((merge_status < 0) || !result_buf.ptr)
 684                                 die("Failed to execute internal merge");
 685
 686                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 687                                             blob_type, result.sha))
 688                                 die("Unable to add %s to database",
 689                                     a->path);
 690
 691                         free(result_buf.ptr);
 692                         result.clean = (merge_status == 0);
 693                 } else if (S_ISGITLINK(a->mode)) {
 694                         result.clean = 0;
 695                         hashcpy(result.sha, a->sha1);
 696                 } else if (S_ISLNK(a->mode)) {
 697                         hashcpy(result.sha, a->sha1);
 698
 699                         if (!sha_eq(a->sha1, b->sha1))
 700                                 result.clean = 0;
 701                 } else {
 702                         die("unsupported object type in the tree");
 703                 }
 704         }
 705
 706         return result;
 707 }
 708
 709 static void conflict_rename_rename(struct merge_options *o,
 710                                    struct rename *ren1,
 711                                    const char *branch1,
 712                                    struct rename *ren2,
 713                                    const char *branch2)
 714 {
 715         char *del[2];
 716         int delp = 0;
 717         const char *ren1_dst = ren1->pair->two->path;
 718         const char *ren2_dst = ren2->pair->two->path;
 719         const char *dst_name1 = ren1_dst;
 720         const char *dst_name2 = ren2_dst;
 721         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 722                 dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 723                 output(o, 1, "%s is a directory in %s adding as %s instead",
 724                        ren1_dst, branch2, dst_name1);
 725                 remove_file(o, 0, ren1_dst, 0);
 726         }
 727         if (string_list_has_string(&current_directory_set, ren2_dst)) {
 728                 dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 729                 output(o, 1, "%s is a directory in %s adding as %s instead",
 730                        ren2_dst, branch1, dst_name2);
 731                 remove_file(o, 0, ren2_dst, 0);
 732         }
 733         if (o->call_depth) {
 734                 remove_file_from_cache(dst_name1);
 735                 remove_file_from_cache(dst_name2);
 736                 /*
 737                  * Uncomment to leave the conflicting names in the resulting tree
 738                  *
 739                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 740                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 741                  */
 742         } else {
 743                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 744                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 745         }
 746         while (delp--)
 747                 free(del[delp]);
 748 }
 749
 750 static void conflict_rename_dir(struct merge_options *o,
 751                                 struct rename *ren1,
 752                                 const char *branch1)
 753 {
 754         char *new_path = unique_path(ren1->pair->two->path, branch1);
 755         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 756         remove_file(o, 0, ren1->pair->two->path, 0);
 757         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 758         free(new_path);
 759 }
 760
 761 static void conflict_rename_rename_2(struct merge_options *o,
 762                                      struct rename *ren1,
 763                                      const char *branch1,
 764                                      struct rename *ren2,
 765                                      const char *branch2)
 766 {
 767         char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 768         char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 769         output(o, 1, "Renaming %s to %s and %s to %s instead",
 770                ren1->pair->one->path, new_path1,
 771                ren2->pair->one->path, new_path2);
 772         remove_file(o, 0, ren1->pair->two->path, 0);
 773         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 774         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 775         free(new_path2);
 776         free(new_path1);
 777 }
 778
 779 static int process_renames(struct merge_options *o,
 780                            struct string_list *a_renames,
 781                            struct string_list *b_renames)
 782 {
 783         int clean_merge = 1, i, j;
 784         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 785         const struct rename *sre;
 786
 787         for (i = 0; i < a_renames->nr; i++) {
 788                 sre = a_renames->items[i].util;
 789                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 790                         = sre->dst_entry;
 791         }
 792         for (i = 0; i < b_renames->nr; i++) {
 793                 sre = b_renames->items[i].util;
 794                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 795                         = sre->dst_entry;
 796         }
 797
 798         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 799                 int compare;
 800                 char *src;
 801                 struct string_list *renames1, *renames2, *renames2Dst;
 802                 struct rename *ren1 = NULL, *ren2 = NULL;
 803                 const char *branch1, *branch2;
 804                 const char *ren1_src, *ren1_dst;
 805
 806                 if (i >= a_renames->nr) {
 807                         compare = 1;
 808                         ren2 = b_renames->items[j++].util;
 809                 } else if (j >= b_renames->nr) {
 810                         compare = -1;
 811                         ren1 = a_renames->items[i++].util;
 812                 } else {
 813                         compare = strcmp(a_renames->items[i].string,
 814                                         b_renames->items[j].string);
 815                         if (compare <= 0)
 816                                 ren1 = a_renames->items[i++].util;
 817                         if (compare >= 0)
 818                                 ren2 = b_renames->items[j++].util;
 819                 }
 820
 821                 /* TODO: refactor, so that 1/2 are not needed */
 822                 if (ren1) {
 823                         renames1 = a_renames;
 824                         renames2 = b_renames;
 825                         renames2Dst = &b_by_dst;
 826                         branch1 = o->branch1;
 827                         branch2 = o->branch2;
 828                 } else {
 829                         struct rename *tmp;
 830                         renames1 = b_renames;
 831                         renames2 = a_renames;
 832                         renames2Dst = &a_by_dst;
 833                         branch1 = o->branch2;
 834                         branch2 = o->branch1;
 835                         tmp = ren2;
 836                         ren2 = ren1;
 837                         ren1 = tmp;
 838                 }
 839                 src = ren1->pair->one->path;
 840
 841                 ren1->dst_entry->processed = 1;
 842                 ren1->src_entry->processed = 1;
 843
 844                 if (ren1->processed)
 845                         continue;
 846                 ren1->processed = 1;
 847
 848                 ren1_src = ren1->pair->one->path;
 849                 ren1_dst = ren1->pair->two->path;
 850
 851                 if (ren2) {
 852                         const char *ren2_src = ren2->pair->one->path;
 853                         const char *ren2_dst = ren2->pair->two->path;
 854                         /* Renamed in 1 and renamed in 2 */
 855                         if (strcmp(ren1_src, ren2_src) != 0)
 856                                 die("ren1.src != ren2.src");
 857                         ren2->dst_entry->processed = 1;
 858                         ren2->processed = 1;
 859                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 860                                 clean_merge = 0;
 861                                 output(o, 1, "CONFLICT (rename/rename): "
 862                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 863                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 864                                        src, ren1_dst, branch1,
 865                                        src, ren2_dst, branch2,
 866                                        o->call_depth ? " (left unresolved)": "");
 867                                 if (o->call_depth) {
 868                                         remove_file_from_cache(src);
 869                                         update_file(o, 0, ren1->pair->one->sha1,
 870                                                     ren1->pair->one->mode, src);
 871                                 }
 872                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 873                         } else {
 874                                 struct merge_file_info mfi;
 875                                 remove_file(o, 1, ren1_src, 1);
 876                                 mfi = merge_file(o,
 877                                                  ren1->pair->one,
 878                                                  ren1->pair->two,
 879                                                  ren2->pair->two,
 880                                                  branch1,
 881                                                  branch2);
 882                                 if (mfi.merge || !mfi.clean)
 883                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 884
 885                                 if (mfi.merge)
 886                                         output(o, 2, "Auto-merging %s", ren1_dst);
 887
 888                                 if (!mfi.clean) {
 889                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 890                                                ren1_dst);
 891                                         clean_merge = 0;
 892
 893                                         if (!o->call_depth)
 894                                                 update_stages(ren1_dst,
 895                                                               ren1->pair->one,
 896                                                               ren1->pair->two,
 897                                                               ren2->pair->two,
 898                                                               1 /* clear */);
 899                                 }
 900                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 901                         }
 902                 } else {
 903                         /* Renamed in 1, maybe changed in 2 */
 904                         struct string_list_item *item;
 905                         /* we only use sha1 and mode of these */
 906                         struct diff_filespec src_other, dst_other;
 907                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 908
 909                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 910
 911                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 912                         src_other.mode = ren1->src_entry->stages[stage].mode;
 913                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 914                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 915
 916                         try_merge = 0;
 917
 918                         if (string_list_has_string(&current_directory_set, ren1_dst)) {
 919                                 clean_merge = 0;
 920                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 921                                        " directory %s added in %s",
 922                                        ren1_src, ren1_dst, branch1,
 923                                        ren1_dst, branch2);
 924                                 conflict_rename_dir(o, ren1, branch1);
 925                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 926                                 clean_merge = 0;
 927                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 928                                        "and deleted in %s",
 929                                        ren1_src, ren1_dst, branch1,
 930                                        branch2);
 931                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 932                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 933                                 const char *new_path;
 934                                 clean_merge = 0;
 935                                 try_merge = 1;
 936                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 937                                        "%s added in %s",
 938                                        ren1_src, ren1_dst, branch1,
 939                                        ren1_dst, branch2);
 940                                 new_path = unique_path(ren1_dst, branch2);
 941                                 output(o, 1, "Adding as %s instead", new_path);
 942                                 update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 943                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 944                                 ren2 = item->util;
 945                                 clean_merge = 0;
 946                                 ren2->processed = 1;
 947                                 output(o, 1, "CONFLICT (rename/rename): "
 948                                        "Rename %s->%s in %s. "
 949                                        "Rename %s->%s in %s",
 950                                        ren1_src, ren1_dst, branch1,
 951                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 952                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
 953                         } else
 954                                 try_merge = 1;
 955
 956                         if (try_merge) {
 957                                 struct diff_filespec *one, *a, *b;
 958                                 struct merge_file_info mfi;
 959                                 src_other.path = (char *)ren1_src;
 960
 961                                 one = ren1->pair->one;
 962                                 if (a_renames == renames1) {
 963                                         a = ren1->pair->two;
 964                                         b = &src_other;
 965                                 } else {
 966                                         b = ren1->pair->two;
 967                                         a = &src_other;
 968                                 }
 969                                 mfi = merge_file(o, one, a, b,
 970                                                 o->branch1, o->branch2);
 971
 972                                 if (mfi.clean &&
 973                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
 974                                     mfi.mode == ren1->pair->two->mode)
 975                                         /*
 976                                          * This messaged is part of
 977                                          * t6022 test. If you change
 978                                          * it update the test too.
 979                                          */
 980                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
 981                                 else {
 982                                         if (mfi.merge || !mfi.clean)
 983                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
 984                                         if (mfi.merge)
 985                                                 output(o, 2, "Auto-merging %s", ren1_dst);
 986                                         if (!mfi.clean) {
 987                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
 988                                                        ren1_dst);
 989                                                 clean_merge = 0;
 990
 991                                                 if (!o->call_depth)
 992                                                         update_stages(ren1_dst,
 993                                                                       one, a, b, 1);
 994                                         }
 995                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 996                                 }
 997                         }
 998                 }
 999         }
1000         string_list_clear(&a_by_dst, 0);
1001         string_list_clear(&b_by_dst, 0);
1002
1003         return clean_merge;
1004 }
1005
1006 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1007 {
1008         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1009 }
1010
1011 /* Per entry merge function */
1012 static int process_entry(struct merge_options *o,
1013                          const char *path, struct stage_data *entry)
1014 {
1015         /*
1016         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1017         print_index_entry("\tpath: ", entry);
1018         */
1019         int clean_merge = 1;
1020         unsigned o_mode = entry->stages[1].mode;
1021         unsigned a_mode = entry->stages[2].mode;
1022         unsigned b_mode = entry->stages[3].mode;
1023         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1024         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1025         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1026
1027         if (o_sha && (!a_sha || !b_sha)) {
1028                 /* Case A: Deleted in one */
1029                 if ((!a_sha && !b_sha) ||
1030                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1031                     (!a_sha && sha_eq(b_sha, o_sha))) {
1032                         /* Deleted in both or deleted in one and
1033                          * unchanged in the other */
1034                         if (a_sha)
1035                                 output(o, 2, "Removing %s", path);
1036                         /* do not touch working file if it did not exist */
1037                         remove_file(o, 1, path, !a_sha);
1038                 } else {
1039                         /* Deleted in one and changed in the other */
1040                         clean_merge = 0;
1041                         if (!a_sha) {
1042                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1043                                        "and modified in %s. Version %s of %s left in tree.",
1044                                        path, o->branch1,
1045                                        o->branch2, o->branch2, path);
1046                                 update_file(o, 0, b_sha, b_mode, path);
1047                         } else {
1048                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1049                                        "and modified in %s. Version %s of %s left in tree.",
1050                                        path, o->branch2,
1051                                        o->branch1, o->branch1, path);
1052                                 update_file(o, 0, a_sha, a_mode, path);
1053                         }
1054                 }
1055
1056         } else if ((!o_sha && a_sha && !b_sha) ||
1057                    (!o_sha && !a_sha && b_sha)) {
1058                 /* Case B: Added in one. */
1059                 const char *add_branch;
1060                 const char *other_branch;
1061                 unsigned mode;
1062                 const unsigned char *sha;
1063                 const char *conf;
1064
1065                 if (a_sha) {
1066                         add_branch = o->branch1;
1067                         other_branch = o->branch2;
1068                         mode = a_mode;
1069                         sha = a_sha;
1070                         conf = "file/directory";
1071                 } else {
1072                         add_branch = o->branch2;
1073                         other_branch = o->branch1;
1074                         mode = b_mode;
1075                         sha = b_sha;
1076                         conf = "directory/file";
1077                 }
1078                 if (string_list_has_string(&current_directory_set, path)) {
1079                         const char *new_path = unique_path(path, add_branch);
1080                         clean_merge = 0;
1081                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1082                                "Adding %s as %s",
1083                                conf, path, other_branch, path, new_path);
1084                         remove_file(o, 0, path, 0);
1085                         update_file(o, 0, sha, mode, new_path);
1086                 } else {
1087                         output(o, 2, "Adding %s", path);
1088                         update_file(o, 1, sha, mode, path);
1089                 }
1090         } else if (a_sha && b_sha) {
1091                 /* Case C: Added in both (check for same permissions) and */
1092                 /* case D: Modified in both, but differently. */
1093                 const char *reason = "content";
1094                 struct merge_file_info mfi;
1095                 struct diff_filespec one, a, b;
1096
1097                 if (!o_sha) {
1098                         reason = "add/add";
1099                         o_sha = (unsigned char *)null_sha1;
1100                 }
1101                 output(o, 2, "Auto-merging %s", path);
1102                 one.path = a.path = b.path = (char *)path;
1103                 hashcpy(one.sha1, o_sha);
1104                 one.mode = o_mode;
1105                 hashcpy(a.sha1, a_sha);
1106                 a.mode = a_mode;
1107                 hashcpy(b.sha1, b_sha);
1108                 b.mode = b_mode;
1109
1110                 mfi = merge_file(o, &one, &a, &b,
1111                                  o->branch1, o->branch2);
1112
1113                 clean_merge = mfi.clean;
1114                 if (mfi.clean)
1115                         update_file(o, 1, mfi.sha, mfi.mode, path);
1116                 else if (S_ISGITLINK(mfi.mode))
1117                         output(o, 1, "CONFLICT (submodule): Merge conflict in %s "
1118                                "- needs %s", path, sha1_to_hex(b.sha1));
1119                 else {
1120                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1121                                         reason, path);
1122
1123                         if (o->call_depth)
1124                                 update_file(o, 0, mfi.sha, mfi.mode, path);
1125                         else
1126                                 update_file_flags(o, mfi.sha, mfi.mode, path,
1127                                               0 /* update_cache */, 1 /* update_working_directory */);
1128                 }
1129         } else if (!o_sha && !a_sha && !b_sha) {
1130                 /*
1131                  * this entry was deleted altogether. a_mode == 0 means
1132                  * we had that path and want to actively remove it.
1133                  */
1134                 remove_file(o, 1, path, !a_mode);
1135         } else
1136                 die("Fatal merge failure, shouldn't happen.");
1137
1138         return clean_merge;
1139 }
1140
1141 int merge_trees(struct merge_options *o,
1142                 struct tree *head,
1143                 struct tree *merge,
1144                 struct tree *common,
1145                 struct tree **result)
1146 {
1147         int code, clean;
1148
1149         if (o->subtree_merge) {
1150                 merge = shift_tree_object(head, merge);
1151                 common = shift_tree_object(head, common);
1152         }
1153
1154         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1155                 output(o, 0, "Already uptodate!");
1156                 *result = head;
1157                 return 1;
1158         }
1159
1160         code = git_merge_trees(o->call_depth, common, head, merge);
1161
1162         if (code != 0)
1163                 die("merging of trees %s and %s failed",
1164                     sha1_to_hex(head->object.sha1),
1165                     sha1_to_hex(merge->object.sha1));
1166
1167         if (unmerged_cache()) {
1168                 struct string_list *entries, *re_head, *re_merge;
1169                 int i;
1170                 string_list_clear(&current_file_set, 1);
1171                 string_list_clear(&current_directory_set, 1);
1172                 get_files_dirs(head);
1173                 get_files_dirs(merge);
1174
1175                 entries = get_unmerged();
1176                 re_head  = get_renames(o, head, common, head, merge, entries);
1177                 re_merge = get_renames(o, merge, common, head, merge, entries);
1178                 clean = process_renames(o, re_head, re_merge);
1179                 for (i = 0; i < entries->nr; i++) {
1180                         const char *path = entries->items[i].string;
1181                         struct stage_data *e = entries->items[i].util;
1182                         if (!e->processed
1183                                 && !process_entry(o, path, e))
1184                                 clean = 0;
1185                 }
1186
1187                 string_list_clear(re_merge, 0);
1188                 string_list_clear(re_head, 0);
1189                 string_list_clear(entries, 1);
1190
1191         }
1192         else
1193                 clean = 1;
1194
1195         if (o->call_depth)
1196                 *result = write_tree_from_memory(o);
1197
1198         return clean;
1199 }
1200
1201 static struct commit_list *reverse_commit_list(struct commit_list *list)
1202 {
1203         struct commit_list *next = NULL, *current, *backup;
1204         for (current = list; current; current = backup) {
1205                 backup = current->next;
1206                 current->next = next;
1207                 next = current;
1208         }
1209         return next;
1210 }
1211
1212 /*
1213  * Merge the commits h1 and h2, return the resulting virtual
1214  * commit object and a flag indicating the cleanness of the merge.
1215  */
1216 int merge_recursive(struct merge_options *o,
1217                     struct commit *h1,
1218                     struct commit *h2,
1219                     struct commit_list *ca,
1220                     struct commit **result)
1221 {
1222         struct commit_list *iter;
1223         struct commit *merged_common_ancestors;
1224         struct tree *mrtree = mrtree;
1225         int clean;
1226
1227         if (show(o, 4)) {
1228                 output(o, 4, "Merging:");
1229                 output_commit_title(o, h1);
1230                 output_commit_title(o, h2);
1231         }
1232
1233         if (!ca) {
1234                 ca = get_merge_bases(h1, h2, 1);
1235                 ca = reverse_commit_list(ca);
1236         }
1237
1238         if (show(o, 5)) {
1239                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1240                 for (iter = ca; iter; iter = iter->next)
1241                         output_commit_title(o, iter->item);
1242         }
1243
1244         merged_common_ancestors = pop_commit(&ca);
1245         if (merged_common_ancestors == NULL) {
1246                 /* if there is no common ancestor, make an empty tree */
1247                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1248
1249                 tree->object.parsed = 1;
1250                 tree->object.type = OBJ_TREE;
1251                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1252                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1253         }
1254
1255         for (iter = ca; iter; iter = iter->next) {
1256                 const char *saved_b1, *saved_b2;
1257                 o->call_depth++;
1258                 /*
1259                  * When the merge fails, the result contains files
1260                  * with conflict markers. The cleanness flag is
1261                  * ignored, it was never actually used, as result of
1262                  * merge_trees has always overwritten it: the committed
1263                  * "conflicts" were already resolved.
1264                  */
1265                 discard_cache();
1266                 saved_b1 = o->branch1;
1267                 saved_b2 = o->branch2;
1268                 o->branch1 = "Temporary merge branch 1";
1269                 o->branch2 = "Temporary merge branch 2";
1270                 merge_recursive(o, merged_common_ancestors, iter->item,
1271                                 NULL, &merged_common_ancestors);
1272                 o->branch1 = saved_b1;
1273                 o->branch2 = saved_b2;
1274                 o->call_depth--;
1275
1276                 if (!merged_common_ancestors)
1277                         die("merge returned no commit");
1278         }
1279
1280         discard_cache();
1281         if (!o->call_depth)
1282                 read_cache();
1283
1284         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1285                             &mrtree);
1286
1287         if (o->call_depth) {
1288                 *result = make_virtual_commit(mrtree, "merged tree");
1289                 commit_list_insert(h1, &(*result)->parents);
1290                 commit_list_insert(h2, &(*result)->parents->next);
1291         }
1292         flush_output();
1293         return clean;
1294 }
1295
1296 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1297 {
1298         struct object *object;
1299
1300         object = deref_tag(parse_object(sha1), name, strlen(name));
1301         if (!object)
1302                 return NULL;
1303         if (object->type == OBJ_TREE)
1304                 return make_virtual_commit((struct tree*)object, name);
1305         if (object->type != OBJ_COMMIT)
1306                 return NULL;
1307         if (parse_commit((struct commit *)object))
1308                 return NULL;
1309         return (struct commit *)object;
1310 }
1311
1312 int merge_recursive_generic(struct merge_options *o,
1313                             const unsigned char *head,
1314                             const unsigned char *merge,
1315                             int num_base_list,
1316                             const unsigned char **base_list,
1317                             struct commit **result)
1318 {
1319         int clean, index_fd;
1320         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1321         struct commit *head_commit = get_ref(head, o->branch1);
1322         struct commit *next_commit = get_ref(merge, o->branch2);
1323         struct commit_list *ca = NULL;
1324
1325         if (base_list) {
1326                 int i;
1327                 for (i = 0; i < num_base_list; ++i) {
1328                         struct commit *base;
1329                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1330                                 return error("Could not parse object '%s'",
1331                                         sha1_to_hex(base_list[i]));
1332                         commit_list_insert(base, &ca);
1333                 }
1334         }
1335
1336         index_fd = hold_locked_index(lock, 1);
1337         clean = merge_recursive(o, head_commit, next_commit, ca,
1338                         result);
1339         if (active_cache_changed &&
1340                         (write_cache(index_fd, active_cache, active_nr) ||
1341                          commit_locked_index(lock)))
1342                 return error("Unable to write index.");
1343
1344         return clean ? 0 : 1;
1345 }
1346
1347 static int merge_recursive_config(const char *var, const char *value, void *cb)
1348 {
1349         struct merge_options *o = cb;
1350         if (!strcasecmp(var, "merge.verbosity")) {
1351                 o->verbosity = git_config_int(var, value);
1352                 return 0;
1353         }
1354         if (!strcasecmp(var, "diff.renamelimit")) {
1355                 o->diff_rename_limit = git_config_int(var, value);
1356                 return 0;
1357         }
1358         if (!strcasecmp(var, "merge.renamelimit")) {
1359                 o->merge_rename_limit = git_config_int(var, value);
1360                 return 0;
1361         }
1362         return git_default_config(var, value, cb);
1363 }
1364
1365 void init_merge_options(struct merge_options *o)
1366 {
1367         memset(o, 0, sizeof(struct merge_options));
1368         o->verbosity = 2;
1369         o->buffer_output = 1;
1370         o->diff_rename_limit = -1;
1371         o->merge_rename_limit = -1;
1372         git_config(merge_recursive_config, o);
1373         if (getenv("GIT_MERGE_VERBOSITY"))
1374                 o->verbosity =
1375                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1376         if (o->verbosity >= 5)
1377                 o->buffer_output = 0;
1378 }