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 "advice.h"
   7 #include "cache.h"
   8 #include "cache-tree.h"
   9 #include "commit.h"
  10 #include "blob.h"
  11 #include "builtin.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "tag.h"
  16 #include "unpack-trees.h"
  17 #include "string-list.h"
  18 #include "xdiff-interface.h"
  19 #include "ll-merge.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22 #include "dir.h"
  23
  24 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  25                                       const char *subtree_shift)
  26 {
  27         unsigned char shifted[20];
  28
  29         if (!*subtree_shift) {
  30                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  31         } else {
  32                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  33                               subtree_shift);
  34         }
  35         if (!hashcmp(two->object.sha1, shifted))
  36                 return two;
  37         return lookup_tree(shifted);
  38 }
  39
  40 /*
  41  * A virtual commit has (const char *)commit->util set to the name.
  42  */
  43
  44 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  45 {
  46         struct commit *commit = xcalloc(1, sizeof(struct commit));
  47         commit->tree = tree;
  48         commit->util = (void*)comment;
  49         /* avoid warnings */
  50         commit->object.parsed = 1;
  51         return commit;
  52 }
  53
  54 /*
  55  * Since we use get_tree_entry(), which does not put the read object into
  56  * the object pool, we cannot rely on a == b.
  57  */
  58 static int sha_eq(const unsigned char *a, const unsigned char *b)
  59 {
  60         if (!a && !b)
  61                 return 2;
  62         return a && b && hashcmp(a, b) == 0;
  63 }
  64
  65 /*
  66  * Since we want to write the index eventually, we cannot reuse the index
  67  * for these (temporary) data.
  68  */
  69 struct stage_data
  70 {
  71         struct
  72         {
  73                 unsigned mode;
  74                 unsigned char sha[20];
  75         } stages[4];
  76         unsigned processed:1;
  77 };
  78
  79 static int show(struct merge_options *o, int v)
  80 {
  81         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  82 }
  83
  84 static void flush_output(struct merge_options *o)
  85 {
  86         if (o->obuf.len) {
  87                 fputs(o->obuf.buf, stdout);
  88                 strbuf_reset(&o->obuf);
  89         }
  90 }
  91
  92 __attribute__((format (printf, 3, 4)))
  93 static void output(struct merge_options *o, int v, const char *fmt, ...)
  94 {
  95         int len;
  96         va_list ap;
  97
  98         if (!show(o, v))
  99                 return;
 100
 101         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 102         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 103         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 104
 105         va_start(ap, fmt);
 106         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 107         va_end(ap);
 108
 109         if (len < 0)
 110                 len = 0;
 111         if (len >= strbuf_avail(&o->obuf)) {
 112                 strbuf_grow(&o->obuf, len + 2);
 113                 va_start(ap, fmt);
 114                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 115                 va_end(ap);
 116                 if (len >= strbuf_avail(&o->obuf)) {
 117                         die("this should not happen, your snprintf is broken");
 118                 }
 119         }
 120         strbuf_setlen(&o->obuf, o->obuf.len + len);
 121         strbuf_add(&o->obuf, "\n", 1);
 122         if (!o->buffer_output)
 123                 flush_output(o);
 124 }
 125
 126 static void output_commit_title(struct merge_options *o, struct commit *commit)
 127 {
 128         int i;
 129         flush_output(o);
 130         for (i = o->call_depth; i--;)
 131                 fputs("  ", stdout);
 132         if (commit->util)
 133                 printf("virtual %s\n", (char *)commit->util);
 134         else {
 135                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 136                 if (parse_commit(commit) != 0)
 137                         printf("(bad commit)\n");
 138                 else {
 139                         const char *s;
 140                         int len;
 141                         for (s = commit->buffer; *s; s++)
 142                                 if (*s == '\n' && s[1] == '\n') {
 143                                         s += 2;
 144                                         break;
 145                                 }
 146                         for (len = 0; s[len] && '\n' != s[len]; len++)
 147                                 ; /* do nothing */
 148                         printf("%.*s\n", len, s);
 149                 }
 150         }
 151 }
 152
 153 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 154                 const char *path, int stage, int refresh, int options)
 155 {
 156         struct cache_entry *ce;
 157         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 158         if (!ce)
 159                 return error("addinfo_cache failed for path '%s'", path);
 160         return add_cache_entry(ce, options);
 161 }
 162
 163 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 164 {
 165         parse_tree(tree);
 166         init_tree_desc(desc, tree->buffer, tree->size);
 167 }
 168
 169 static int git_merge_trees(int index_only,
 170                            struct tree *common,
 171                            struct tree *head,
 172                            struct tree *merge)
 173 {
 174         int rc;
 175         struct tree_desc t[3];
 176         struct unpack_trees_options opts;
 177
 178         memset(&opts, 0, sizeof(opts));
 179         if (index_only)
 180                 opts.index_only = 1;
 181         else
 182                 opts.update = 1;
 183         opts.merge = 1;
 184         opts.head_idx = 2;
 185         opts.fn = threeway_merge;
 186         opts.src_index = &the_index;
 187         opts.dst_index = &the_index;
 188         opts.msgs = get_porcelain_error_msgs();
 189
 190         init_tree_desc_from_tree(t+0, common);
 191         init_tree_desc_from_tree(t+1, head);
 192         init_tree_desc_from_tree(t+2, merge);
 193
 194         rc = unpack_trees(3, t, &opts);
 195         cache_tree_free(&active_cache_tree);
 196         return rc;
 197 }
 198
 199 struct tree *write_tree_from_memory(struct merge_options *o)
 200 {
 201         struct tree *result = NULL;
 202
 203         if (unmerged_cache()) {
 204                 int i;
 205                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 206                 for (i = 0; i < active_nr; i++) {
 207                         struct cache_entry *ce = active_cache[i];
 208                         if (ce_stage(ce))
 209                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 210                                         (int)ce_namelen(ce), ce->name);
 211                 }
 212                 die("Bug in merge-recursive.c");
 213         }
 214
 215         if (!active_cache_tree)
 216                 active_cache_tree = cache_tree();
 217
 218         if (!cache_tree_fully_valid(active_cache_tree) &&
 219             cache_tree_update(active_cache_tree,
 220                               active_cache, active_nr, 0, 0) < 0)
 221                 die("error building trees");
 222
 223         result = lookup_tree(active_cache_tree->sha1);
 224
 225         return result;
 226 }
 227
 228 static int save_files_dirs(const unsigned char *sha1,
 229                 const char *base, int baselen, const char *path,
 230                 unsigned int mode, int stage, void *context)
 231 {
 232         int len = strlen(path);
 233         char *newpath = xmalloc(baselen + len + 1);
 234         struct merge_options *o = context;
 235
 236         memcpy(newpath, base, baselen);
 237         memcpy(newpath + baselen, path, len);
 238         newpath[baselen + len] = '\0';
 239
 240         if (S_ISDIR(mode))
 241                 string_list_insert(newpath, &o->current_directory_set);
 242         else
 243                 string_list_insert(newpath, &o->current_file_set);
 244         free(newpath);
 245
 246         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 247 }
 248
 249 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 250 {
 251         int n;
 252         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 253                 return 0;
 254         n = o->current_file_set.nr + o->current_directory_set.nr;
 255         return n;
 256 }
 257
 258 /*
 259  * Returns an index_entry instance which doesn't have to correspond to
 260  * a real cache entry in Git's index.
 261  */
 262 static struct stage_data *insert_stage_data(const char *path,
 263                 struct tree *o, struct tree *a, struct tree *b,
 264                 struct string_list *entries)
 265 {
 266         struct string_list_item *item;
 267         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 268         get_tree_entry(o->object.sha1, path,
 269                         e->stages[1].sha, &e->stages[1].mode);
 270         get_tree_entry(a->object.sha1, path,
 271                         e->stages[2].sha, &e->stages[2].mode);
 272         get_tree_entry(b->object.sha1, path,
 273                         e->stages[3].sha, &e->stages[3].mode);
 274         item = string_list_insert(path, entries);
 275         item->util = e;
 276         return e;
 277 }
 278
 279 /*
 280  * Create a dictionary mapping file names to stage_data objects. The
 281  * dictionary contains one entry for every path with a non-zero stage entry.
 282  */
 283 static struct string_list *get_unmerged(void)
 284 {
 285         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 286         int i;
 287
 288         unmerged->strdup_strings = 1;
 289
 290         for (i = 0; i < active_nr; i++) {
 291                 struct string_list_item *item;
 292                 struct stage_data *e;
 293                 struct cache_entry *ce = active_cache[i];
 294                 if (!ce_stage(ce))
 295                         continue;
 296
 297                 item = string_list_lookup(ce->name, unmerged);
 298                 if (!item) {
 299                         item = string_list_insert(ce->name, unmerged);
 300                         item->util = xcalloc(1, sizeof(struct stage_data));
 301                 }
 302                 e = item->util;
 303                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 304                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 305         }
 306
 307         return unmerged;
 308 }
 309
 310 struct rename
 311 {
 312         struct diff_filepair *pair;
 313         struct stage_data *src_entry;
 314         struct stage_data *dst_entry;
 315         unsigned processed:1;
 316 };
 317
 318 /*
 319  * Get information of all renames which occurred between 'o_tree' and
 320  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 321  * 'b_tree') to be able to associate the correct cache entries with
 322  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 323  */
 324 static struct string_list *get_renames(struct merge_options *o,
 325                                        struct tree *tree,
 326                                        struct tree *o_tree,
 327                                        struct tree *a_tree,
 328                                        struct tree *b_tree,
 329                                        struct string_list *entries)
 330 {
 331         int i;
 332         struct string_list *renames;
 333         struct diff_options opts;
 334
 335         renames = xcalloc(1, sizeof(struct string_list));
 336         diff_setup(&opts);
 337         DIFF_OPT_SET(&opts, RECURSIVE);
 338         opts.detect_rename = DIFF_DETECT_RENAME;
 339         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 340                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 341                             500;
 342         opts.warn_on_too_large_rename = 1;
 343         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 344         if (diff_setup_done(&opts) < 0)
 345                 die("diff setup failed");
 346         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 347         diffcore_std(&opts);
 348         for (i = 0; i < diff_queued_diff.nr; ++i) {
 349                 struct string_list_item *item;
 350                 struct rename *re;
 351                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 352                 if (pair->status != 'R') {
 353                         diff_free_filepair(pair);
 354                         continue;
 355                 }
 356                 re = xmalloc(sizeof(*re));
 357                 re->processed = 0;
 358                 re->pair = pair;
 359                 item = string_list_lookup(re->pair->one->path, entries);
 360                 if (!item)
 361                         re->src_entry = insert_stage_data(re->pair->one->path,
 362                                         o_tree, a_tree, b_tree, entries);
 363                 else
 364                         re->src_entry = item->util;
 365
 366                 item = string_list_lookup(re->pair->two->path, entries);
 367                 if (!item)
 368                         re->dst_entry = insert_stage_data(re->pair->two->path,
 369                                         o_tree, a_tree, b_tree, entries);
 370                 else
 371                         re->dst_entry = item->util;
 372                 item = string_list_insert(pair->one->path, renames);
 373                 item->util = re;
 374         }
 375         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 376         diff_queued_diff.nr = 0;
 377         diff_flush(&opts);
 378         return renames;
 379 }
 380
 381 static int update_stages(const char *path, struct diff_filespec *o,
 382                          struct diff_filespec *a, struct diff_filespec *b,
 383                          int clear)
 384 {
 385         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 386         if (clear)
 387                 if (remove_file_from_cache(path))
 388                         return -1;
 389         if (o)
 390                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 391                         return -1;
 392         if (a)
 393                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 394                         return -1;
 395         if (b)
 396                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 397                         return -1;
 398         return 0;
 399 }
 400
 401 static int remove_file(struct merge_options *o, int clean,
 402                        const char *path, int no_wd)
 403 {
 404         int update_cache = o->call_depth || clean;
 405         int update_working_directory = !o->call_depth && !no_wd;
 406
 407         if (update_cache) {
 408                 if (remove_file_from_cache(path))
 409                         return -1;
 410         }
 411         if (update_working_directory) {
 412                 if (remove_path(path) && errno != ENOENT)
 413                         return -1;
 414         }
 415         return 0;
 416 }
 417
 418 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 419 {
 420         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 421         int suffix = 0;
 422         struct stat st;
 423         char *p = newpath + strlen(path);
 424         strcpy(newpath, path);
 425         *(p++) = '~';
 426         strcpy(p, branch);
 427         for (; *p; ++p)
 428                 if ('/' == *p)
 429                         *p = '_';
 430         while (string_list_has_string(&o->current_file_set, newpath) ||
 431                string_list_has_string(&o->current_directory_set, newpath) ||
 432                lstat(newpath, &st) == 0)
 433                 sprintf(p, "_%d", suffix++);
 434
 435         string_list_insert(newpath, &o->current_file_set);
 436         return newpath;
 437 }
 438
 439 static void flush_buffer(int fd, const char *buf, unsigned long size)
 440 {
 441         while (size > 0) {
 442                 long ret = write_in_full(fd, buf, size);
 443                 if (ret < 0) {
 444                         /* Ignore epipe */
 445                         if (errno == EPIPE)
 446                                 break;
 447                         die_errno("merge-recursive");
 448                 } else if (!ret) {
 449                         die("merge-recursive: disk full?");
 450                 }
 451                 size -= ret;
 452                 buf += ret;
 453         }
 454 }
 455
 456 static int would_lose_untracked(const char *path)
 457 {
 458         int pos = cache_name_pos(path, strlen(path));
 459
 460         if (pos < 0)
 461                 pos = -1 - pos;
 462         while (pos < active_nr &&
 463                !strcmp(path, active_cache[pos]->name)) {
 464                 /*
 465                  * If stage #0, it is definitely tracked.
 466                  * If it has stage #2 then it was tracked
 467                  * before this merge started.  All other
 468                  * cases the path was not tracked.
 469                  */
 470                 switch (ce_stage(active_cache[pos])) {
 471                 case 0:
 472                 case 2:
 473                         return 0;
 474                 }
 475                 pos++;
 476         }
 477         return file_exists(path);
 478 }
 479
 480 static int make_room_for_path(const char *path)
 481 {
 482         int status;
 483         const char *msg = "failed to create path '%s'%s";
 484
 485         status = safe_create_leading_directories_const(path);
 486         if (status) {
 487                 if (status == -3) {
 488                         /* something else exists */
 489                         error(msg, path, ": perhaps a D/F conflict?");
 490                         return -1;
 491                 }
 492                 die(msg, path, "");
 493         }
 494
 495         /*
 496          * Do not unlink a file in the work tree if we are not
 497          * tracking it.
 498          */
 499         if (would_lose_untracked(path))
 500                 return error("refusing to lose untracked file at '%s'",
 501                              path);
 502
 503         /* Successful unlink is good.. */
 504         if (!unlink(path))
 505                 return 0;
 506         /* .. and so is no existing file */
 507         if (errno == ENOENT)
 508                 return 0;
 509         /* .. but not some other error (who really cares what?) */
 510         return error(msg, path, ": perhaps a D/F conflict?");
 511 }
 512
 513 static void update_file_flags(struct merge_options *o,
 514                               const unsigned char *sha,
 515                               unsigned mode,
 516                               const char *path,
 517                               int update_cache,
 518                               int update_wd)
 519 {
 520         if (o->call_depth)
 521                 update_wd = 0;
 522
 523         if (update_wd) {
 524                 enum object_type type;
 525                 void *buf;
 526                 unsigned long size;
 527
 528                 if (S_ISGITLINK(mode))
 529                         /*
 530                          * We may later decide to recursively descend into
 531                          * the submodule directory and update its index
 532                          * and/or work tree, but we do not do that now.
 533                          */
 534                         goto update_index;
 535
 536                 buf = read_sha1_file(sha, &type, &size);
 537                 if (!buf)
 538                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 539                 if (type != OBJ_BLOB)
 540                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 541                 if (S_ISREG(mode)) {
 542                         struct strbuf strbuf = STRBUF_INIT;
 543                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 544                                 free(buf);
 545                                 size = strbuf.len;
 546                                 buf = strbuf_detach(&strbuf, NULL);
 547                         }
 548                 }
 549
 550                 if (make_room_for_path(path) < 0) {
 551                         update_wd = 0;
 552                         free(buf);
 553                         goto update_index;
 554                 }
 555                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 556                         int fd;
 557                         if (mode & 0100)
 558                                 mode = 0777;
 559                         else
 560                                 mode = 0666;
 561                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 562                         if (fd < 0)
 563                                 die_errno("failed to open '%s'", path);
 564                         flush_buffer(fd, buf, size);
 565                         close(fd);
 566                 } else if (S_ISLNK(mode)) {
 567                         char *lnk = xmemdupz(buf, size);
 568                         safe_create_leading_directories_const(path);
 569                         unlink(path);
 570                         if (symlink(lnk, path))
 571                                 die_errno("failed to symlink '%s'", path);
 572                         free(lnk);
 573                 } else
 574                         die("do not know what to do with %06o %s '%s'",
 575                             mode, sha1_to_hex(sha), path);
 576                 free(buf);
 577         }
 578  update_index:
 579         if (update_cache)
 580                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 581 }
 582
 583 static void update_file(struct merge_options *o,
 584                         int clean,
 585                         const unsigned char *sha,
 586                         unsigned mode,
 587                         const char *path)
 588 {
 589         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 590 }
 591
 592 /* Low level file merging, update and removal */
 593
 594 struct merge_file_info
 595 {
 596         unsigned char sha[20];
 597         unsigned mode;
 598         unsigned clean:1,
 599                  merge:1;
 600 };
 601
 602 static int merge_3way(struct merge_options *o,
 603                       mmbuffer_t *result_buf,
 604                       struct diff_filespec *one,
 605                       struct diff_filespec *a,
 606                       struct diff_filespec *b,
 607                       const char *branch1,
 608                       const char *branch2)
 609 {
 610         mmfile_t orig, src1, src2;
 611         char *name1, *name2;
 612         int merge_status;
 613         int favor;
 614
 615         if (o->call_depth)
 616                 favor = 0;
 617         else {
 618                 switch (o->recursive_variant) {
 619                 case MERGE_RECURSIVE_OURS:
 620                         favor = XDL_MERGE_FAVOR_OURS;
 621                         break;
 622                 case MERGE_RECURSIVE_THEIRS:
 623                         favor = XDL_MERGE_FAVOR_THEIRS;
 624                         break;
 625                 default:
 626                         favor = 0;
 627                         break;
 628                 }
 629         }
 630
 631         if (strcmp(a->path, b->path)) {
 632                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 633                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 634         } else {
 635                 name1 = xstrdup(mkpath("%s", branch1));
 636                 name2 = xstrdup(mkpath("%s", branch2));
 637         }
 638
 639         read_mmblob(&orig, one->sha1);
 640         read_mmblob(&src1, a->sha1);
 641         read_mmblob(&src2, b->sha1);
 642
 643         merge_status = ll_merge(result_buf, a->path, &orig,
 644                                 &src1, name1, &src2, name2,
 645                                 (!!o->call_depth) | (favor << 1));
 646
 647         free(name1);
 648         free(name2);
 649         free(orig.ptr);
 650         free(src1.ptr);
 651         free(src2.ptr);
 652         return merge_status;
 653 }
 654
 655 static struct merge_file_info merge_file(struct merge_options *o,
 656                                          struct diff_filespec *one,
 657                                          struct diff_filespec *a,
 658                                          struct diff_filespec *b,
 659                                          const char *branch1,
 660                                          const char *branch2)
 661 {
 662         struct merge_file_info result;
 663         result.merge = 0;
 664         result.clean = 1;
 665
 666         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 667                 result.clean = 0;
 668                 if (S_ISREG(a->mode)) {
 669                         result.mode = a->mode;
 670                         hashcpy(result.sha, a->sha1);
 671                 } else {
 672                         result.mode = b->mode;
 673                         hashcpy(result.sha, b->sha1);
 674                 }
 675         } else {
 676                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 677                         result.merge = 1;
 678
 679                 /*
 680                  * Merge modes
 681                  */
 682                 if (a->mode == b->mode || a->mode == one->mode)
 683                         result.mode = b->mode;
 684                 else {
 685                         result.mode = a->mode;
 686                         if (b->mode != one->mode) {
 687                                 result.clean = 0;
 688                                 result.merge = 1;
 689                         }
 690                 }
 691
 692                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 693                         hashcpy(result.sha, b->sha1);
 694                 else if (sha_eq(b->sha1, one->sha1))
 695                         hashcpy(result.sha, a->sha1);
 696                 else if (S_ISREG(a->mode)) {
 697                         mmbuffer_t result_buf;
 698                         int merge_status;
 699
 700                         merge_status = merge_3way(o, &result_buf, one, a, b,
 701                                                   branch1, branch2);
 702
 703                         if ((merge_status < 0) || !result_buf.ptr)
 704                                 die("Failed to execute internal merge");
 705
 706                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 707                                             blob_type, result.sha))
 708                                 die("Unable to add %s to database",
 709                                     a->path);
 710
 711                         free(result_buf.ptr);
 712                         result.clean = (merge_status == 0);
 713                 } else if (S_ISGITLINK(a->mode)) {
 714                         result.clean = 0;
 715                         hashcpy(result.sha, a->sha1);
 716                 } else if (S_ISLNK(a->mode)) {
 717                         hashcpy(result.sha, a->sha1);
 718
 719                         if (!sha_eq(a->sha1, b->sha1))
 720                                 result.clean = 0;
 721                 } else {
 722                         die("unsupported object type in the tree");
 723                 }
 724         }
 725
 726         return result;
 727 }
 728
 729 static void conflict_rename_rename(struct merge_options *o,
 730                                    struct rename *ren1,
 731                                    const char *branch1,
 732                                    struct rename *ren2,
 733                                    const char *branch2)
 734 {
 735         char *del[2];
 736         int delp = 0;
 737         const char *ren1_dst = ren1->pair->two->path;
 738         const char *ren2_dst = ren2->pair->two->path;
 739         const char *dst_name1 = ren1_dst;
 740         const char *dst_name2 = ren2_dst;
 741         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 742                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 743                 output(o, 1, "%s is a directory in %s adding as %s instead",
 744                        ren1_dst, branch2, dst_name1);
 745                 remove_file(o, 0, ren1_dst, 0);
 746         }
 747         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 748                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 749                 output(o, 1, "%s is a directory in %s adding as %s instead",
 750                        ren2_dst, branch1, dst_name2);
 751                 remove_file(o, 0, ren2_dst, 0);
 752         }
 753         if (o->call_depth) {
 754                 remove_file_from_cache(dst_name1);
 755                 remove_file_from_cache(dst_name2);
 756                 /*
 757                  * Uncomment to leave the conflicting names in the resulting tree
 758                  *
 759                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 760                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 761                  */
 762         } else {
 763                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 764                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 765         }
 766         while (delp--)
 767                 free(del[delp]);
 768 }
 769
 770 static void conflict_rename_dir(struct merge_options *o,
 771                                 struct rename *ren1,
 772                                 const char *branch1)
 773 {
 774         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 775         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 776         remove_file(o, 0, ren1->pair->two->path, 0);
 777         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 778         free(new_path);
 779 }
 780
 781 static void conflict_rename_rename_2(struct merge_options *o,
 782                                      struct rename *ren1,
 783                                      const char *branch1,
 784                                      struct rename *ren2,
 785                                      const char *branch2)
 786 {
 787         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 788         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 789         output(o, 1, "Renaming %s to %s and %s to %s instead",
 790                ren1->pair->one->path, new_path1,
 791                ren2->pair->one->path, new_path2);
 792         remove_file(o, 0, ren1->pair->two->path, 0);
 793         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 794         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 795         free(new_path2);
 796         free(new_path1);
 797 }
 798
 799 static int process_renames(struct merge_options *o,
 800                            struct string_list *a_renames,
 801                            struct string_list *b_renames)
 802 {
 803         int clean_merge = 1, i, j;
 804         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 805         const struct rename *sre;
 806
 807         for (i = 0; i < a_renames->nr; i++) {
 808                 sre = a_renames->items[i].util;
 809                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 810                         = sre->dst_entry;
 811         }
 812         for (i = 0; i < b_renames->nr; i++) {
 813                 sre = b_renames->items[i].util;
 814                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 815                         = sre->dst_entry;
 816         }
 817
 818         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 819                 char *src;
 820                 struct string_list *renames1, *renames2Dst;
 821                 struct rename *ren1 = NULL, *ren2 = NULL;
 822                 const char *branch1, *branch2;
 823                 const char *ren1_src, *ren1_dst;
 824
 825                 if (i >= a_renames->nr) {
 826                         ren2 = b_renames->items[j++].util;
 827                 } else if (j >= b_renames->nr) {
 828                         ren1 = a_renames->items[i++].util;
 829                 } else {
 830                         int compare = strcmp(a_renames->items[i].string,
 831                                              b_renames->items[j].string);
 832                         if (compare <= 0)
 833                                 ren1 = a_renames->items[i++].util;
 834                         if (compare >= 0)
 835                                 ren2 = b_renames->items[j++].util;
 836                 }
 837
 838                 /* TODO: refactor, so that 1/2 are not needed */
 839                 if (ren1) {
 840                         renames1 = a_renames;
 841                         renames2Dst = &b_by_dst;
 842                         branch1 = o->branch1;
 843                         branch2 = o->branch2;
 844                 } else {
 845                         struct rename *tmp;
 846                         renames1 = b_renames;
 847                         renames2Dst = &a_by_dst;
 848                         branch1 = o->branch2;
 849                         branch2 = o->branch1;
 850                         tmp = ren2;
 851                         ren2 = ren1;
 852                         ren1 = tmp;
 853                 }
 854                 src = ren1->pair->one->path;
 855
 856                 ren1->dst_entry->processed = 1;
 857                 ren1->src_entry->processed = 1;
 858
 859                 if (ren1->processed)
 860                         continue;
 861                 ren1->processed = 1;
 862
 863                 ren1_src = ren1->pair->one->path;
 864                 ren1_dst = ren1->pair->two->path;
 865
 866                 if (ren2) {
 867                         const char *ren2_src = ren2->pair->one->path;
 868                         const char *ren2_dst = ren2->pair->two->path;
 869                         /* Renamed in 1 and renamed in 2 */
 870                         if (strcmp(ren1_src, ren2_src) != 0)
 871                                 die("ren1.src != ren2.src");
 872                         ren2->dst_entry->processed = 1;
 873                         ren2->processed = 1;
 874                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 875                                 clean_merge = 0;
 876                                 output(o, 1, "CONFLICT (rename/rename): "
 877                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 878                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 879                                        src, ren1_dst, branch1,
 880                                        src, ren2_dst, branch2,
 881                                        o->call_depth ? " (left unresolved)": "");
 882                                 if (o->call_depth) {
 883                                         remove_file_from_cache(src);
 884                                         update_file(o, 0, ren1->pair->one->sha1,
 885                                                     ren1->pair->one->mode, src);
 886                                 }
 887                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 888                         } else {
 889                                 struct merge_file_info mfi;
 890                                 remove_file(o, 1, ren1_src, 1);
 891                                 mfi = merge_file(o,
 892                                                  ren1->pair->one,
 893                                                  ren1->pair->two,
 894                                                  ren2->pair->two,
 895                                                  branch1,
 896                                                  branch2);
 897                                 if (mfi.merge || !mfi.clean)
 898                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 899
 900                                 if (mfi.merge)
 901                                         output(o, 2, "Auto-merging %s", ren1_dst);
 902
 903                                 if (!mfi.clean) {
 904                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 905                                                ren1_dst);
 906                                         clean_merge = 0;
 907
 908                                         if (!o->call_depth)
 909                                                 update_stages(ren1_dst,
 910                                                               ren1->pair->one,
 911                                                               ren1->pair->two,
 912                                                               ren2->pair->two,
 913                                                               1 /* clear */);
 914                                 }
 915                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 916                         }
 917                 } else {
 918                         /* Renamed in 1, maybe changed in 2 */
 919                         struct string_list_item *item;
 920                         /* we only use sha1 and mode of these */
 921                         struct diff_filespec src_other, dst_other;
 922                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 923
 924                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 925
 926                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 927                         src_other.mode = ren1->src_entry->stages[stage].mode;
 928                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 929                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 930
 931                         try_merge = 0;
 932
 933                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 934                                 clean_merge = 0;
 935                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 936                                        " directory %s added in %s",
 937                                        ren1_src, ren1_dst, branch1,
 938                                        ren1_dst, branch2);
 939                                 conflict_rename_dir(o, ren1, branch1);
 940                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 941                                 clean_merge = 0;
 942                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 943                                        "and deleted in %s",
 944                                        ren1_src, ren1_dst, branch1,
 945                                        branch2);
 946                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 947                                 if (!o->call_depth)
 948                                         update_stages(ren1_dst, NULL,
 949                                                         branch1 == o->branch1 ?
 950                                                         ren1->pair->two : NULL,
 951                                                         branch1 == o->branch1 ?
 952                                                         NULL : ren1->pair->two, 1);
 953                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 954                                 const char *new_path;
 955                                 clean_merge = 0;
 956                                 try_merge = 1;
 957                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 958                                        "%s added in %s",
 959                                        ren1_src, ren1_dst, branch1,
 960                                        ren1_dst, branch2);
 961                                 if (o->call_depth) {
 962                                         struct merge_file_info mfi;
 963                                         struct diff_filespec one, a, b;
 964
 965                                         one.path = a.path = b.path =
 966                                                 (char *)ren1_dst;
 967                                         hashcpy(one.sha1, null_sha1);
 968                                         one.mode = 0;
 969                                         hashcpy(a.sha1, ren1->pair->two->sha1);
 970                                         a.mode = ren1->pair->two->mode;
 971                                         hashcpy(b.sha1, dst_other.sha1);
 972                                         b.mode = dst_other.mode;
 973                                         mfi = merge_file(o, &one, &a, &b,
 974                                                          branch1,
 975                                                          branch2);
 976                                         output(o, 1, "Adding merged %s", ren1_dst);
 977                                         update_file(o, 0,
 978                                                     mfi.sha,
 979                                                     mfi.mode,
 980                                                     ren1_dst);
 981                                 } else {
 982                                         new_path = unique_path(o, ren1_dst, branch2);
 983                                         output(o, 1, "Adding as %s instead", new_path);
 984                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 985                                 }
 986                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 987                                 ren2 = item->util;
 988                                 clean_merge = 0;
 989                                 ren2->processed = 1;
 990                                 output(o, 1, "CONFLICT (rename/rename): "
 991                                        "Rename %s->%s in %s. "
 992                                        "Rename %s->%s in %s",
 993                                        ren1_src, ren1_dst, branch1,
 994                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 995                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
 996                         } else
 997                                 try_merge = 1;
 998
 999                         if (try_merge) {
1000                                 struct diff_filespec *one, *a, *b;
1001                                 struct merge_file_info mfi;
1002                                 src_other.path = (char *)ren1_src;
1003
1004                                 one = ren1->pair->one;
1005                                 if (a_renames == renames1) {
1006                                         a = ren1->pair->two;
1007                                         b = &src_other;
1008                                 } else {
1009                                         b = ren1->pair->two;
1010                                         a = &src_other;
1011                                 }
1012                                 mfi = merge_file(o, one, a, b,
1013                                                 o->branch1, o->branch2);
1014
1015                                 if (mfi.clean &&
1016                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1017                                     mfi.mode == ren1->pair->two->mode)
1018                                         /*
1019                                          * This messaged is part of
1020                                          * t6022 test. If you change
1021                                          * it update the test too.
1022                                          */
1023                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1024                                 else {
1025                                         if (mfi.merge || !mfi.clean)
1026                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1027                                         if (mfi.merge)
1028                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1029                                         if (!mfi.clean) {
1030                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1031                                                        ren1_dst);
1032                                                 clean_merge = 0;
1033
1034                                                 if (!o->call_depth)
1035                                                         update_stages(ren1_dst,
1036                                                                       one, a, b, 1);
1037                                         }
1038                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1039                                 }
1040                         }
1041                 }
1042         }
1043         string_list_clear(&a_by_dst, 0);
1044         string_list_clear(&b_by_dst, 0);
1045
1046         return clean_merge;
1047 }
1048
1049 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1050 {
1051         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1052 }
1053
1054 /* Per entry merge function */
1055 static int process_entry(struct merge_options *o,
1056                          const char *path, struct stage_data *entry)
1057 {
1058         /*
1059         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1060         print_index_entry("\tpath: ", entry);
1061         */
1062         int clean_merge = 1;
1063         unsigned o_mode = entry->stages[1].mode;
1064         unsigned a_mode = entry->stages[2].mode;
1065         unsigned b_mode = entry->stages[3].mode;
1066         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1067         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1068         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1069
1070         if (o_sha && (!a_sha || !b_sha)) {
1071                 /* Case A: Deleted in one */
1072                 if ((!a_sha && !b_sha) ||
1073                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1074                     (!a_sha && sha_eq(b_sha, o_sha))) {
1075                         /* Deleted in both or deleted in one and
1076                          * unchanged in the other */
1077                         if (a_sha)
1078                                 output(o, 2, "Removing %s", path);
1079                         /* do not touch working file if it did not exist */
1080                         remove_file(o, 1, path, !a_sha);
1081                 } else {
1082                         /* Deleted in one and changed in the other */
1083                         clean_merge = 0;
1084                         if (!a_sha) {
1085                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1086                                        "and modified in %s. Version %s of %s left in tree.",
1087                                        path, o->branch1,
1088                                        o->branch2, o->branch2, path);
1089                                 update_file(o, 0, b_sha, b_mode, path);
1090                         } else {
1091                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1092                                        "and modified in %s. Version %s of %s left in tree.",
1093                                        path, o->branch2,
1094                                        o->branch1, o->branch1, path);
1095                                 update_file(o, 0, a_sha, a_mode, path);
1096                         }
1097                 }
1098
1099         } else if ((!o_sha && a_sha && !b_sha) ||
1100                    (!o_sha && !a_sha && b_sha)) {
1101                 /* Case B: Added in one. */
1102                 const char *add_branch;
1103                 const char *other_branch;
1104                 unsigned mode;
1105                 const unsigned char *sha;
1106                 const char *conf;
1107
1108                 if (a_sha) {
1109                         add_branch = o->branch1;
1110                         other_branch = o->branch2;
1111                         mode = a_mode;
1112                         sha = a_sha;
1113                         conf = "file/directory";
1114                 } else {
1115                         add_branch = o->branch2;
1116                         other_branch = o->branch1;
1117                         mode = b_mode;
1118                         sha = b_sha;
1119                         conf = "directory/file";
1120                 }
1121                 if (string_list_has_string(&o->current_directory_set, path)) {
1122                         const char *new_path = unique_path(o, path, add_branch);
1123                         clean_merge = 0;
1124                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1125                                "Adding %s as %s",
1126                                conf, path, other_branch, path, new_path);
1127                         remove_file(o, 0, path, 0);
1128                         update_file(o, 0, sha, mode, new_path);
1129                 } else {
1130                         output(o, 2, "Adding %s", path);
1131                         update_file(o, 1, sha, mode, path);
1132                 }
1133         } else if (a_sha && b_sha) {
1134                 /* Case C: Added in both (check for same permissions) and */
1135                 /* case D: Modified in both, but differently. */
1136                 const char *reason = "content";
1137                 struct merge_file_info mfi;
1138                 struct diff_filespec one, a, b;
1139
1140                 if (!o_sha) {
1141                         reason = "add/add";
1142                         o_sha = (unsigned char *)null_sha1;
1143                 }
1144                 output(o, 2, "Auto-merging %s", path);
1145                 one.path = a.path = b.path = (char *)path;
1146                 hashcpy(one.sha1, o_sha);
1147                 one.mode = o_mode;
1148                 hashcpy(a.sha1, a_sha);
1149                 a.mode = a_mode;
1150                 hashcpy(b.sha1, b_sha);
1151                 b.mode = b_mode;
1152
1153                 mfi = merge_file(o, &one, &a, &b,
1154                                  o->branch1, o->branch2);
1155
1156                 clean_merge = mfi.clean;
1157                 if (!mfi.clean) {
1158                         if (S_ISGITLINK(mfi.mode))
1159                                 reason = "submodule";
1160                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1161                                         reason, path);
1162                 }
1163                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1164         } else if (!o_sha && !a_sha && !b_sha) {
1165                 /*
1166                  * this entry was deleted altogether. a_mode == 0 means
1167                  * we had that path and want to actively remove it.
1168                  */
1169                 remove_file(o, 1, path, !a_mode);
1170         } else
1171                 die("Fatal merge failure, shouldn't happen.");
1172
1173         return clean_merge;
1174 }
1175
1176 struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
1177 {
1178         struct unpack_trees_error_msgs msgs = {
1179                 /* would_overwrite */
1180                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1181                 /* not_uptodate_file */
1182                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1183                 /* not_uptodate_dir */
1184                 "Updating '%s' would lose untracked files in it.  Aborting.",
1185                 /* would_lose_untracked */
1186                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
1187                 /* bind_overlap -- will not happen here */
1188                 NULL,
1189         };
1190         if (advice_commit_before_merge) {
1191                 msgs.would_overwrite = msgs.not_uptodate_file =
1192                         "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
1193                         "Please, commit your changes or stash them before you can merge.";
1194         }
1195         return msgs;
1196 }
1197
1198 int merge_trees(struct merge_options *o,
1199                 struct tree *head,
1200                 struct tree *merge,
1201                 struct tree *common,
1202                 struct tree **result)
1203 {
1204         int code, clean;
1205
1206         if (o->subtree_shift) {
1207                 merge = shift_tree_object(head, merge, o->subtree_shift);
1208                 common = shift_tree_object(head, common, o->subtree_shift);
1209         }
1210
1211         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1212                 output(o, 0, "Already uptodate!");
1213                 *result = head;
1214                 return 1;
1215         }
1216
1217         code = git_merge_trees(o->call_depth, common, head, merge);
1218
1219         if (code != 0) {
1220                 if (show(o, 4) || o->call_depth)
1221                         die("merging of trees %s and %s failed",
1222                             sha1_to_hex(head->object.sha1),
1223                             sha1_to_hex(merge->object.sha1));
1224                 else
1225                         exit(128);
1226         }
1227
1228         if (unmerged_cache()) {
1229                 struct string_list *entries, *re_head, *re_merge;
1230                 int i;
1231                 string_list_clear(&o->current_file_set, 1);
1232                 string_list_clear(&o->current_directory_set, 1);
1233                 get_files_dirs(o, head);
1234                 get_files_dirs(o, merge);
1235
1236                 entries = get_unmerged();
1237                 re_head  = get_renames(o, head, common, head, merge, entries);
1238                 re_merge = get_renames(o, merge, common, head, merge, entries);
1239                 clean = process_renames(o, re_head, re_merge);
1240                 for (i = 0; i < entries->nr; i++) {
1241                         const char *path = entries->items[i].string;
1242                         struct stage_data *e = entries->items[i].util;
1243                         if (!e->processed
1244                                 && !process_entry(o, path, e))
1245                                 clean = 0;
1246                 }
1247
1248                 string_list_clear(re_merge, 0);
1249                 string_list_clear(re_head, 0);
1250                 string_list_clear(entries, 1);
1251
1252         }
1253         else
1254                 clean = 1;
1255
1256         if (o->call_depth)
1257                 *result = write_tree_from_memory(o);
1258
1259         return clean;
1260 }
1261
1262 static struct commit_list *reverse_commit_list(struct commit_list *list)
1263 {
1264         struct commit_list *next = NULL, *current, *backup;
1265         for (current = list; current; current = backup) {
1266                 backup = current->next;
1267                 current->next = next;
1268                 next = current;
1269         }
1270         return next;
1271 }
1272
1273 /*
1274  * Merge the commits h1 and h2, return the resulting virtual
1275  * commit object and a flag indicating the cleanness of the merge.
1276  */
1277 int merge_recursive(struct merge_options *o,
1278                     struct commit *h1,
1279                     struct commit *h2,
1280                     struct commit_list *ca,
1281                     struct commit **result)
1282 {
1283         struct commit_list *iter;
1284         struct commit *merged_common_ancestors;
1285         struct tree *mrtree = mrtree;
1286         int clean;
1287
1288         if (show(o, 4)) {
1289                 output(o, 4, "Merging:");
1290                 output_commit_title(o, h1);
1291                 output_commit_title(o, h2);
1292         }
1293
1294         if (!ca) {
1295                 ca = get_merge_bases(h1, h2, 1);
1296                 ca = reverse_commit_list(ca);
1297         }
1298
1299         if (show(o, 5)) {
1300                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1301                 for (iter = ca; iter; iter = iter->next)
1302                         output_commit_title(o, iter->item);
1303         }
1304
1305         merged_common_ancestors = pop_commit(&ca);
1306         if (merged_common_ancestors == NULL) {
1307                 /* if there is no common ancestor, make an empty tree */
1308                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1309
1310                 tree->object.parsed = 1;
1311                 tree->object.type = OBJ_TREE;
1312                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1313                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1314         }
1315
1316         for (iter = ca; iter; iter = iter->next) {
1317                 const char *saved_b1, *saved_b2;
1318                 o->call_depth++;
1319                 /*
1320                  * When the merge fails, the result contains files
1321                  * with conflict markers. The cleanness flag is
1322                  * ignored, it was never actually used, as result of
1323                  * merge_trees has always overwritten it: the committed
1324                  * "conflicts" were already resolved.
1325                  */
1326                 discard_cache();
1327                 saved_b1 = o->branch1;
1328                 saved_b2 = o->branch2;
1329                 o->branch1 = "Temporary merge branch 1";
1330                 o->branch2 = "Temporary merge branch 2";
1331                 merge_recursive(o, merged_common_ancestors, iter->item,
1332                                 NULL, &merged_common_ancestors);
1333                 o->branch1 = saved_b1;
1334                 o->branch2 = saved_b2;
1335                 o->call_depth--;
1336
1337                 if (!merged_common_ancestors)
1338                         die("merge returned no commit");
1339         }
1340
1341         discard_cache();
1342         if (!o->call_depth)
1343                 read_cache();
1344
1345         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1346                             &mrtree);
1347
1348         if (o->call_depth) {
1349                 *result = make_virtual_commit(mrtree, "merged tree");
1350                 commit_list_insert(h1, &(*result)->parents);
1351                 commit_list_insert(h2, &(*result)->parents->next);
1352         }
1353         flush_output(o);
1354         return clean;
1355 }
1356
1357 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1358 {
1359         struct object *object;
1360
1361         object = deref_tag(parse_object(sha1), name, strlen(name));
1362         if (!object)
1363                 return NULL;
1364         if (object->type == OBJ_TREE)
1365                 return make_virtual_commit((struct tree*)object, name);
1366         if (object->type != OBJ_COMMIT)
1367                 return NULL;
1368         if (parse_commit((struct commit *)object))
1369                 return NULL;
1370         return (struct commit *)object;
1371 }
1372
1373 int merge_recursive_generic(struct merge_options *o,
1374                             const unsigned char *head,
1375                             const unsigned char *merge,
1376                             int num_base_list,
1377                             const unsigned char **base_list,
1378                             struct commit **result)
1379 {
1380         int clean, index_fd;
1381         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1382         struct commit *head_commit = get_ref(head, o->branch1);
1383         struct commit *next_commit = get_ref(merge, o->branch2);
1384         struct commit_list *ca = NULL;
1385
1386         if (base_list) {
1387                 int i;
1388                 for (i = 0; i < num_base_list; ++i) {
1389                         struct commit *base;
1390                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1391                                 return error("Could not parse object '%s'",
1392                                         sha1_to_hex(base_list[i]));
1393                         commit_list_insert(base, &ca);
1394                 }
1395         }
1396
1397         index_fd = hold_locked_index(lock, 1);
1398         clean = merge_recursive(o, head_commit, next_commit, ca,
1399                         result);
1400         if (active_cache_changed &&
1401                         (write_cache(index_fd, active_cache, active_nr) ||
1402                          commit_locked_index(lock)))
1403                 return error("Unable to write index.");
1404
1405         return clean ? 0 : 1;
1406 }
1407
1408 static int merge_recursive_config(const char *var, const char *value, void *cb)
1409 {
1410         struct merge_options *o = cb;
1411         if (!strcasecmp(var, "merge.verbosity")) {
1412                 o->verbosity = git_config_int(var, value);
1413                 return 0;
1414         }
1415         if (!strcasecmp(var, "diff.renamelimit")) {
1416                 o->diff_rename_limit = git_config_int(var, value);
1417                 return 0;
1418         }
1419         if (!strcasecmp(var, "merge.renamelimit")) {
1420                 o->merge_rename_limit = git_config_int(var, value);
1421                 return 0;
1422         }
1423         return git_xmerge_config(var, value, cb);
1424 }
1425
1426 void init_merge_options(struct merge_options *o)
1427 {
1428         memset(o, 0, sizeof(struct merge_options));
1429         o->verbosity = 2;
1430         o->buffer_output = 1;
1431         o->diff_rename_limit = -1;
1432         o->merge_rename_limit = -1;
1433         git_config(merge_recursive_config, o);
1434         if (getenv("GIT_MERGE_VERBOSITY"))
1435                 o->verbosity =
1436                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1437         if (o->verbosity >= 5)
1438                 o->buffer_output = 0;
1439         strbuf_init(&o->obuf, 0);
1440         memset(&o->current_file_set, 0, sizeof(struct string_list));
1441         o->current_file_set.strdup_strings = 1;
1442         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1443         o->current_directory_set.strdup_strings = 1;
1444 }