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 #include "submodule.h"
  24
  25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  26                                       const char *subtree_shift)
  27 {
  28         unsigned char shifted[20];
  29
  30         if (!*subtree_shift) {
  31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  32         } else {
  33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  34                               subtree_shift);
  35         }
  36         if (!hashcmp(two->object.sha1, shifted))
  37                 return two;
  38         return lookup_tree(shifted);
  39 }
  40
  41 /*
  42  * A virtual commit has (const char *)commit->util set to the name.
  43  */
  44
  45 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  46 {
  47         struct commit *commit = xcalloc(1, sizeof(struct commit));
  48         commit->tree = tree;
  49         commit->util = (void*)comment;
  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 int show(struct merge_options *o, int v)
  81 {
  82         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  83 }
  84
  85 static void flush_output(struct merge_options *o)
  86 {
  87         if (o->obuf.len) {
  88                 fputs(o->obuf.buf, stdout);
  89                 strbuf_reset(&o->obuf);
  90         }
  91 }
  92
  93 __attribute__((format (printf, 3, 4)))
  94 static void output(struct merge_options *o, int v, const char *fmt, ...)
  95 {
  96         int len;
  97         va_list ap;
  98
  99         if (!show(o, v))
 100                 return;
 101
 102         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 103         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 104         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 105
 106         va_start(ap, fmt);
 107         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 108         va_end(ap);
 109
 110         if (len < 0)
 111                 len = 0;
 112         if (len >= strbuf_avail(&o->obuf)) {
 113                 strbuf_grow(&o->obuf, len + 2);
 114                 va_start(ap, fmt);
 115                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 116                 va_end(ap);
 117                 if (len >= strbuf_avail(&o->obuf)) {
 118                         die("this should not happen, your snprintf is broken");
 119                 }
 120         }
 121         strbuf_setlen(&o->obuf, o->obuf.len + len);
 122         strbuf_add(&o->obuf, "\n", 1);
 123         if (!o->buffer_output)
 124                 flush_output(o);
 125 }
 126
 127 static void output_commit_title(struct merge_options *o, struct commit *commit)
 128 {
 129         int i;
 130         flush_output(o);
 131         for (i = o->call_depth; i--;)
 132                 fputs("  ", stdout);
 133         if (commit->util)
 134                 printf("virtual %s\n", (char *)commit->util);
 135         else {
 136                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 137                 if (parse_commit(commit) != 0)
 138                         printf("(bad commit)\n");
 139                 else {
 140                         const char *s;
 141                         int len;
 142                         for (s = commit->buffer; *s; s++)
 143                                 if (*s == '\n' && s[1] == '\n') {
 144                                         s += 2;
 145                                         break;
 146                                 }
 147                         for (len = 0; s[len] && '\n' != s[len]; len++)
 148                                 ; /* do nothing */
 149                         printf("%.*s\n", len, s);
 150                 }
 151         }
 152 }
 153
 154 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 155                 const char *path, int stage, int refresh, int options)
 156 {
 157         struct cache_entry *ce;
 158         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 159         if (!ce)
 160                 return error("addinfo_cache failed for path '%s'", path);
 161         return add_cache_entry(ce, options);
 162 }
 163
 164 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 165 {
 166         parse_tree(tree);
 167         init_tree_desc(desc, tree->buffer, tree->size);
 168 }
 169
 170 static int git_merge_trees(int index_only,
 171                            struct tree *common,
 172                            struct tree *head,
 173                            struct tree *merge)
 174 {
 175         int rc;
 176         struct tree_desc t[3];
 177         struct unpack_trees_options opts;
 178
 179         memset(&opts, 0, sizeof(opts));
 180         if (index_only)
 181                 opts.index_only = 1;
 182         else
 183                 opts.update = 1;
 184         opts.merge = 1;
 185         opts.head_idx = 2;
 186         opts.fn = threeway_merge;
 187         opts.src_index = &the_index;
 188         opts.dst_index = &the_index;
 189         opts.msgs = get_porcelain_error_msgs();
 190
 191         init_tree_desc_from_tree(t+0, common);
 192         init_tree_desc_from_tree(t+1, head);
 193         init_tree_desc_from_tree(t+2, merge);
 194
 195         rc = unpack_trees(3, t, &opts);
 196         cache_tree_free(&active_cache_tree);
 197         return rc;
 198 }
 199
 200 struct tree *write_tree_from_memory(struct merge_options *o)
 201 {
 202         struct tree *result = NULL;
 203
 204         if (unmerged_cache()) {
 205                 int i;
 206                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 207                 for (i = 0; i < active_nr; i++) {
 208                         struct cache_entry *ce = active_cache[i];
 209                         if (ce_stage(ce))
 210                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 211                                         (int)ce_namelen(ce), ce->name);
 212                 }
 213                 die("Bug in merge-recursive.c");
 214         }
 215
 216         if (!active_cache_tree)
 217                 active_cache_tree = cache_tree();
 218
 219         if (!cache_tree_fully_valid(active_cache_tree) &&
 220             cache_tree_update(active_cache_tree,
 221                               active_cache, active_nr, 0, 0) < 0)
 222                 die("error building trees");
 223
 224         result = lookup_tree(active_cache_tree->sha1);
 225
 226         return result;
 227 }
 228
 229 static int save_files_dirs(const unsigned char *sha1,
 230                 const char *base, int baselen, const char *path,
 231                 unsigned int mode, int stage, void *context)
 232 {
 233         int len = strlen(path);
 234         char *newpath = xmalloc(baselen + len + 1);
 235         struct merge_options *o = context;
 236
 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(&o->current_directory_set, newpath);
 243         else
 244                 string_list_insert(&o->current_file_set, newpath);
 245         free(newpath);
 246
 247         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 248 }
 249
 250 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 251 {
 252         int n;
 253         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 254                 return 0;
 255         n = o->current_file_set.nr + o->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(entries, path);
 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(unmerged, ce->name);
 299                 if (!item) {
 300                         item = string_list_insert(unmerged, ce->name);
 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(entries, re->pair->one->path);
 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(entries, re->pair->two->path);
 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(renames, pair->one->path);
 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_file(struct merge_options *o, int clean,
 403                        const char *path, int no_wd)
 404 {
 405         int update_cache = o->call_depth || clean;
 406         int update_working_directory = !o->call_depth && !no_wd;
 407
 408         if (update_cache) {
 409                 if (remove_file_from_cache(path))
 410                         return -1;
 411         }
 412         if (update_working_directory) {
 413                 if (remove_path(path))
 414                         return -1;
 415         }
 416         return 0;
 417 }
 418
 419 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 420 {
 421         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 422         int suffix = 0;
 423         struct stat st;
 424         char *p = newpath + strlen(path);
 425         strcpy(newpath, path);
 426         *(p++) = '~';
 427         strcpy(p, branch);
 428         for (; *p; ++p)
 429                 if ('/' == *p)
 430                         *p = '_';
 431         while (string_list_has_string(&o->current_file_set, newpath) ||
 432                string_list_has_string(&o->current_directory_set, newpath) ||
 433                lstat(newpath, &st) == 0)
 434                 sprintf(p, "_%d", suffix++);
 435
 436         string_list_insert(&o->current_file_set, newpath);
 437         return newpath;
 438 }
 439
 440 static void flush_buffer(int fd, const char *buf, unsigned long size)
 441 {
 442         while (size > 0) {
 443                 long ret = write_in_full(fd, buf, size);
 444                 if (ret < 0) {
 445                         /* Ignore epipe */
 446                         if (errno == EPIPE)
 447                                 break;
 448                         die_errno("merge-recursive");
 449                 } else if (!ret) {
 450                         die("merge-recursive: disk full?");
 451                 }
 452                 size -= ret;
 453                 buf += ret;
 454         }
 455 }
 456
 457 static int would_lose_untracked(const char *path)
 458 {
 459         int pos = cache_name_pos(path, strlen(path));
 460
 461         if (pos < 0)
 462                 pos = -1 - pos;
 463         while (pos < active_nr &&
 464                !strcmp(path, active_cache[pos]->name)) {
 465                 /*
 466                  * If stage #0, it is definitely tracked.
 467                  * If it has stage #2 then it was tracked
 468                  * before this merge started.  All other
 469                  * cases the path was not tracked.
 470                  */
 471                 switch (ce_stage(active_cache[pos])) {
 472                 case 0:
 473                 case 2:
 474                         return 0;
 475                 }
 476                 pos++;
 477         }
 478         return file_exists(path);
 479 }
 480
 481 static int make_room_for_path(const char *path)
 482 {
 483         int status;
 484         const char *msg = "failed to create path '%s'%s";
 485
 486         status = safe_create_leading_directories_const(path);
 487         if (status) {
 488                 if (status == -3) {
 489                         /* something else exists */
 490                         error(msg, path, ": perhaps a D/F conflict?");
 491                         return -1;
 492                 }
 493                 die(msg, path, "");
 494         }
 495
 496         /*
 497          * Do not unlink a file in the work tree if we are not
 498          * tracking it.
 499          */
 500         if (would_lose_untracked(path))
 501                 return error("refusing to lose untracked file at '%s'",
 502                              path);
 503
 504         /* Successful unlink is good.. */
 505         if (!unlink(path))
 506                 return 0;
 507         /* .. and so is no existing file */
 508         if (errno == ENOENT)
 509                 return 0;
 510         /* .. but not some other error (who really cares what?) */
 511         return error(msg, path, ": perhaps a D/F conflict?");
 512 }
 513
 514 static void update_file_flags(struct merge_options *o,
 515                               const unsigned char *sha,
 516                               unsigned mode,
 517                               const char *path,
 518                               int update_cache,
 519                               int update_wd)
 520 {
 521         if (o->call_depth)
 522                 update_wd = 0;
 523
 524         if (update_wd) {
 525                 enum object_type type;
 526                 void *buf;
 527                 unsigned long size;
 528
 529                 if (S_ISGITLINK(mode)) {
 530                         /*
 531                          * We may later decide to recursively descend into
 532                          * the submodule directory and update its index
 533                          * and/or work tree, but we do not do that now.
 534                          */
 535                         update_wd = 0;
 536                         goto update_index;
 537                 }
 538
 539                 buf = read_sha1_file(sha, &type, &size);
 540                 if (!buf)
 541                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 542                 if (type != OBJ_BLOB)
 543                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 544                 if (S_ISREG(mode)) {
 545                         struct strbuf strbuf = STRBUF_INIT;
 546                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 547                                 free(buf);
 548                                 size = strbuf.len;
 549                                 buf = strbuf_detach(&strbuf, NULL);
 550                         }
 551                 }
 552
 553                 if (make_room_for_path(path) < 0) {
 554                         update_wd = 0;
 555                         free(buf);
 556                         goto update_index;
 557                 }
 558                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 559                         int fd;
 560                         if (mode & 0100)
 561                                 mode = 0777;
 562                         else
 563                                 mode = 0666;
 564                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 565                         if (fd < 0)
 566                                 die_errno("failed to open '%s'", path);
 567                         flush_buffer(fd, buf, size);
 568                         close(fd);
 569                 } else if (S_ISLNK(mode)) {
 570                         char *lnk = xmemdupz(buf, size);
 571                         safe_create_leading_directories_const(path);
 572                         unlink(path);
 573                         if (symlink(lnk, path))
 574                                 die_errno("failed to symlink '%s'", path);
 575                         free(lnk);
 576                 } else
 577                         die("do not know what to do with %06o %s '%s'",
 578                             mode, sha1_to_hex(sha), path);
 579                 free(buf);
 580         }
 581  update_index:
 582         if (update_cache)
 583                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 584 }
 585
 586 static void update_file(struct merge_options *o,
 587                         int clean,
 588                         const unsigned char *sha,
 589                         unsigned mode,
 590                         const char *path)
 591 {
 592         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 593 }
 594
 595 /* Low level file merging, update and removal */
 596
 597 struct merge_file_info
 598 {
 599         unsigned char sha[20];
 600         unsigned mode;
 601         unsigned clean:1,
 602                  merge:1;
 603 };
 604
 605 static int merge_3way(struct merge_options *o,
 606                       mmbuffer_t *result_buf,
 607                       struct diff_filespec *one,
 608                       struct diff_filespec *a,
 609                       struct diff_filespec *b,
 610                       const char *branch1,
 611                       const char *branch2)
 612 {
 613         mmfile_t orig, src1, src2;
 614         char *base_name, *name1, *name2;
 615         int merge_status;
 616         int favor;
 617
 618         if (o->call_depth)
 619                 favor = 0;
 620         else {
 621                 switch (o->recursive_variant) {
 622                 case MERGE_RECURSIVE_OURS:
 623                         favor = XDL_MERGE_FAVOR_OURS;
 624                         break;
 625                 case MERGE_RECURSIVE_THEIRS:
 626                         favor = XDL_MERGE_FAVOR_THEIRS;
 627                         break;
 628                 default:
 629                         favor = 0;
 630                         break;
 631                 }
 632         }
 633
 634         if (strcmp(a->path, b->path) ||
 635             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 636                 base_name = o->ancestor == NULL ? NULL :
 637                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 638                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 639                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 640         } else {
 641                 base_name = o->ancestor == NULL ? NULL :
 642                         xstrdup(mkpath("%s", o->ancestor));
 643                 name1 = xstrdup(mkpath("%s", branch1));
 644                 name2 = xstrdup(mkpath("%s", branch2));
 645         }
 646
 647         read_mmblob(&orig, one->sha1);
 648         read_mmblob(&src1, a->sha1);
 649         read_mmblob(&src2, b->sha1);
 650
 651         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 652                                 &src1, name1, &src2, name2,
 653                                 (!!o->call_depth) | (favor << 1));
 654
 655         free(name1);
 656         free(name2);
 657         free(orig.ptr);
 658         free(src1.ptr);
 659         free(src2.ptr);
 660         return merge_status;
 661 }
 662
 663 static struct merge_file_info merge_file(struct merge_options *o,
 664                                          struct diff_filespec *one,
 665                                          struct diff_filespec *a,
 666                                          struct diff_filespec *b,
 667                                          const char *branch1,
 668                                          const char *branch2)
 669 {
 670         struct merge_file_info result;
 671         result.merge = 0;
 672         result.clean = 1;
 673
 674         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 675                 result.clean = 0;
 676                 if (S_ISREG(a->mode)) {
 677                         result.mode = a->mode;
 678                         hashcpy(result.sha, a->sha1);
 679                 } else {
 680                         result.mode = b->mode;
 681                         hashcpy(result.sha, b->sha1);
 682                 }
 683         } else {
 684                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 685                         result.merge = 1;
 686
 687                 /*
 688                  * Merge modes
 689                  */
 690                 if (a->mode == b->mode || a->mode == one->mode)
 691                         result.mode = b->mode;
 692                 else {
 693                         result.mode = a->mode;
 694                         if (b->mode != one->mode) {
 695                                 result.clean = 0;
 696                                 result.merge = 1;
 697                         }
 698                 }
 699
 700                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 701                         hashcpy(result.sha, b->sha1);
 702                 else if (sha_eq(b->sha1, one->sha1))
 703                         hashcpy(result.sha, a->sha1);
 704                 else if (S_ISREG(a->mode)) {
 705                         mmbuffer_t result_buf;
 706                         int merge_status;
 707
 708                         merge_status = merge_3way(o, &result_buf, one, a, b,
 709                                                   branch1, branch2);
 710
 711                         if ((merge_status < 0) || !result_buf.ptr)
 712                                 die("Failed to execute internal merge");
 713
 714                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 715                                             blob_type, result.sha))
 716                                 die("Unable to add %s to database",
 717                                     a->path);
 718
 719                         free(result_buf.ptr);
 720                         result.clean = (merge_status == 0);
 721                 } else if (S_ISGITLINK(a->mode)) {
 722                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 723                                                        a->sha1, b->sha1);
 724                 } else if (S_ISLNK(a->mode)) {
 725                         hashcpy(result.sha, a->sha1);
 726
 727                         if (!sha_eq(a->sha1, b->sha1))
 728                                 result.clean = 0;
 729                 } else {
 730                         die("unsupported object type in the tree");
 731                 }
 732         }
 733
 734         return result;
 735 }
 736
 737 static void conflict_rename_rename(struct merge_options *o,
 738                                    struct rename *ren1,
 739                                    const char *branch1,
 740                                    struct rename *ren2,
 741                                    const char *branch2)
 742 {
 743         char *del[2];
 744         int delp = 0;
 745         const char *ren1_dst = ren1->pair->two->path;
 746         const char *ren2_dst = ren2->pair->two->path;
 747         const char *dst_name1 = ren1_dst;
 748         const char *dst_name2 = ren2_dst;
 749         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 750                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 751                 output(o, 1, "%s is a directory in %s adding as %s instead",
 752                        ren1_dst, branch2, dst_name1);
 753                 remove_file(o, 0, ren1_dst, 0);
 754         }
 755         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 756                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 757                 output(o, 1, "%s is a directory in %s adding as %s instead",
 758                        ren2_dst, branch1, dst_name2);
 759                 remove_file(o, 0, ren2_dst, 0);
 760         }
 761         if (o->call_depth) {
 762                 remove_file_from_cache(dst_name1);
 763                 remove_file_from_cache(dst_name2);
 764                 /*
 765                  * Uncomment to leave the conflicting names in the resulting tree
 766                  *
 767                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 768                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 769                  */
 770         } else {
 771                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 772                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 773         }
 774         while (delp--)
 775                 free(del[delp]);
 776 }
 777
 778 static void conflict_rename_dir(struct merge_options *o,
 779                                 struct rename *ren1,
 780                                 const char *branch1)
 781 {
 782         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 783         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 784         remove_file(o, 0, ren1->pair->two->path, 0);
 785         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 786         free(new_path);
 787 }
 788
 789 static void conflict_rename_rename_2(struct merge_options *o,
 790                                      struct rename *ren1,
 791                                      const char *branch1,
 792                                      struct rename *ren2,
 793                                      const char *branch2)
 794 {
 795         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 796         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 797         output(o, 1, "Renaming %s to %s and %s to %s instead",
 798                ren1->pair->one->path, new_path1,
 799                ren2->pair->one->path, new_path2);
 800         remove_file(o, 0, ren1->pair->two->path, 0);
 801         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 802         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 803         free(new_path2);
 804         free(new_path1);
 805 }
 806
 807 static int process_renames(struct merge_options *o,
 808                            struct string_list *a_renames,
 809                            struct string_list *b_renames)
 810 {
 811         int clean_merge = 1, i, j;
 812         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 813         const struct rename *sre;
 814
 815         for (i = 0; i < a_renames->nr; i++) {
 816                 sre = a_renames->items[i].util;
 817                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 818                         = sre->dst_entry;
 819         }
 820         for (i = 0; i < b_renames->nr; i++) {
 821                 sre = b_renames->items[i].util;
 822                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 823                         = sre->dst_entry;
 824         }
 825
 826         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 827                 char *src;
 828                 struct string_list *renames1, *renames2Dst;
 829                 struct rename *ren1 = NULL, *ren2 = NULL;
 830                 const char *branch1, *branch2;
 831                 const char *ren1_src, *ren1_dst;
 832
 833                 if (i >= a_renames->nr) {
 834                         ren2 = b_renames->items[j++].util;
 835                 } else if (j >= b_renames->nr) {
 836                         ren1 = a_renames->items[i++].util;
 837                 } else {
 838                         int compare = strcmp(a_renames->items[i].string,
 839                                              b_renames->items[j].string);
 840                         if (compare <= 0)
 841                                 ren1 = a_renames->items[i++].util;
 842                         if (compare >= 0)
 843                                 ren2 = b_renames->items[j++].util;
 844                 }
 845
 846                 /* TODO: refactor, so that 1/2 are not needed */
 847                 if (ren1) {
 848                         renames1 = a_renames;
 849                         renames2Dst = &b_by_dst;
 850                         branch1 = o->branch1;
 851                         branch2 = o->branch2;
 852                 } else {
 853                         struct rename *tmp;
 854                         renames1 = b_renames;
 855                         renames2Dst = &a_by_dst;
 856                         branch1 = o->branch2;
 857                         branch2 = o->branch1;
 858                         tmp = ren2;
 859                         ren2 = ren1;
 860                         ren1 = tmp;
 861                 }
 862                 src = ren1->pair->one->path;
 863
 864                 ren1->dst_entry->processed = 1;
 865                 ren1->src_entry->processed = 1;
 866
 867                 if (ren1->processed)
 868                         continue;
 869                 ren1->processed = 1;
 870
 871                 ren1_src = ren1->pair->one->path;
 872                 ren1_dst = ren1->pair->two->path;
 873
 874                 if (ren2) {
 875                         const char *ren2_src = ren2->pair->one->path;
 876                         const char *ren2_dst = ren2->pair->two->path;
 877                         /* Renamed in 1 and renamed in 2 */
 878                         if (strcmp(ren1_src, ren2_src) != 0)
 879                                 die("ren1.src != ren2.src");
 880                         ren2->dst_entry->processed = 1;
 881                         ren2->processed = 1;
 882                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 883                                 clean_merge = 0;
 884                                 output(o, 1, "CONFLICT (rename/rename): "
 885                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 886                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 887                                        src, ren1_dst, branch1,
 888                                        src, ren2_dst, branch2,
 889                                        o->call_depth ? " (left unresolved)": "");
 890                                 if (o->call_depth) {
 891                                         remove_file_from_cache(src);
 892                                         update_file(o, 0, ren1->pair->one->sha1,
 893                                                     ren1->pair->one->mode, src);
 894                                 }
 895                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 896                         } else {
 897                                 struct merge_file_info mfi;
 898                                 remove_file(o, 1, ren1_src, 1);
 899                                 mfi = merge_file(o,
 900                                                  ren1->pair->one,
 901                                                  ren1->pair->two,
 902                                                  ren2->pair->two,
 903                                                  branch1,
 904                                                  branch2);
 905                                 if (mfi.merge || !mfi.clean)
 906                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 907
 908                                 if (mfi.merge)
 909                                         output(o, 2, "Auto-merging %s", ren1_dst);
 910
 911                                 if (!mfi.clean) {
 912                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 913                                                ren1_dst);
 914                                         clean_merge = 0;
 915
 916                                         if (!o->call_depth)
 917                                                 update_stages(ren1_dst,
 918                                                               ren1->pair->one,
 919                                                               ren1->pair->two,
 920                                                               ren2->pair->two,
 921                                                               1 /* clear */);
 922                                 }
 923                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 924                         }
 925                 } else {
 926                         /* Renamed in 1, maybe changed in 2 */
 927                         struct string_list_item *item;
 928                         /* we only use sha1 and mode of these */
 929                         struct diff_filespec src_other, dst_other;
 930                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 931
 932                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 933
 934                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 935                         src_other.mode = ren1->src_entry->stages[stage].mode;
 936                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 937                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 938
 939                         try_merge = 0;
 940
 941                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 942                                 clean_merge = 0;
 943                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 944                                        " directory %s added in %s",
 945                                        ren1_src, ren1_dst, branch1,
 946                                        ren1_dst, branch2);
 947                                 conflict_rename_dir(o, ren1, branch1);
 948                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 949                                 clean_merge = 0;
 950                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 951                                        "and deleted in %s",
 952                                        ren1_src, ren1_dst, branch1,
 953                                        branch2);
 954                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 955                                 if (!o->call_depth)
 956                                         update_stages(ren1_dst, NULL,
 957                                                         branch1 == o->branch1 ?
 958                                                         ren1->pair->two : NULL,
 959                                                         branch1 == o->branch1 ?
 960                                                         NULL : ren1->pair->two, 1);
 961                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 962                                 const char *new_path;
 963                                 clean_merge = 0;
 964                                 try_merge = 1;
 965                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 966                                        "%s added in %s",
 967                                        ren1_src, ren1_dst, branch1,
 968                                        ren1_dst, branch2);
 969                                 if (o->call_depth) {
 970                                         struct merge_file_info mfi;
 971                                         struct diff_filespec one, a, b;
 972
 973                                         one.path = a.path = b.path =
 974                                                 (char *)ren1_dst;
 975                                         hashcpy(one.sha1, null_sha1);
 976                                         one.mode = 0;
 977                                         hashcpy(a.sha1, ren1->pair->two->sha1);
 978                                         a.mode = ren1->pair->two->mode;
 979                                         hashcpy(b.sha1, dst_other.sha1);
 980                                         b.mode = dst_other.mode;
 981                                         mfi = merge_file(o, &one, &a, &b,
 982                                                          branch1,
 983                                                          branch2);
 984                                         output(o, 1, "Adding merged %s", ren1_dst);
 985                                         update_file(o, 0,
 986                                                     mfi.sha,
 987                                                     mfi.mode,
 988                                                     ren1_dst);
 989                                 } else {
 990                                         new_path = unique_path(o, ren1_dst, branch2);
 991                                         output(o, 1, "Adding as %s instead", new_path);
 992                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 993                                 }
 994                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
 995                                 ren2 = item->util;
 996                                 clean_merge = 0;
 997                                 ren2->processed = 1;
 998                                 output(o, 1, "CONFLICT (rename/rename): "
 999                                        "Rename %s->%s in %s. "
1000                                        "Rename %s->%s in %s",
1001                                        ren1_src, ren1_dst, branch1,
1002                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1003                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1004                         } else
1005                                 try_merge = 1;
1006
1007                         if (try_merge) {
1008                                 struct diff_filespec *one, *a, *b;
1009                                 struct merge_file_info mfi;
1010                                 src_other.path = (char *)ren1_src;
1011
1012                                 one = ren1->pair->one;
1013                                 if (a_renames == renames1) {
1014                                         a = ren1->pair->two;
1015                                         b = &src_other;
1016                                 } else {
1017                                         b = ren1->pair->two;
1018                                         a = &src_other;
1019                                 }
1020                                 mfi = merge_file(o, one, a, b,
1021                                                 o->branch1, o->branch2);
1022
1023                                 if (mfi.clean &&
1024                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1025                                     mfi.mode == ren1->pair->two->mode)
1026                                         /*
1027                                          * This messaged is part of
1028                                          * t6022 test. If you change
1029                                          * it update the test too.
1030                                          */
1031                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1032                                 else {
1033                                         if (mfi.merge || !mfi.clean)
1034                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1035                                         if (mfi.merge)
1036                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1037                                         if (!mfi.clean) {
1038                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1039                                                        ren1_dst);
1040                                                 clean_merge = 0;
1041
1042                                                 if (!o->call_depth)
1043                                                         update_stages(ren1_dst,
1044                                                                       one, a, b, 1);
1045                                         }
1046                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1047                                 }
1048                         }
1049                 }
1050         }
1051         string_list_clear(&a_by_dst, 0);
1052         string_list_clear(&b_by_dst, 0);
1053
1054         return clean_merge;
1055 }
1056
1057 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1058 {
1059         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1060 }
1061
1062 /* Per entry merge function */
1063 static int process_entry(struct merge_options *o,
1064                          const char *path, struct stage_data *entry)
1065 {
1066         /*
1067         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1068         print_index_entry("\tpath: ", entry);
1069         */
1070         int clean_merge = 1;
1071         unsigned o_mode = entry->stages[1].mode;
1072         unsigned a_mode = entry->stages[2].mode;
1073         unsigned b_mode = entry->stages[3].mode;
1074         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1075         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1076         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1077
1078         if (o_sha && (!a_sha || !b_sha)) {
1079                 /* Case A: Deleted in one */
1080                 if ((!a_sha && !b_sha) ||
1081                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1082                     (!a_sha && sha_eq(b_sha, o_sha))) {
1083                         /* Deleted in both or deleted in one and
1084                          * unchanged in the other */
1085                         if (a_sha)
1086                                 output(o, 2, "Removing %s", path);
1087                         /* do not touch working file if it did not exist */
1088                         remove_file(o, 1, path, !a_sha);
1089                 } else {
1090                         /* Deleted in one and changed in the other */
1091                         clean_merge = 0;
1092                         if (!a_sha) {
1093                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1094                                        "and modified in %s. Version %s of %s left in tree.",
1095                                        path, o->branch1,
1096                                        o->branch2, o->branch2, path);
1097                                 update_file(o, 0, b_sha, b_mode, path);
1098                         } else {
1099                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1100                                        "and modified in %s. Version %s of %s left in tree.",
1101                                        path, o->branch2,
1102                                        o->branch1, o->branch1, path);
1103                                 update_file(o, 0, a_sha, a_mode, path);
1104                         }
1105                 }
1106
1107         } else if ((!o_sha && a_sha && !b_sha) ||
1108                    (!o_sha && !a_sha && b_sha)) {
1109                 /* Case B: Added in one. */
1110                 const char *add_branch;
1111                 const char *other_branch;
1112                 unsigned mode;
1113                 const unsigned char *sha;
1114                 const char *conf;
1115
1116                 if (a_sha) {
1117                         add_branch = o->branch1;
1118                         other_branch = o->branch2;
1119                         mode = a_mode;
1120                         sha = a_sha;
1121                         conf = "file/directory";
1122                 } else {
1123                         add_branch = o->branch2;
1124                         other_branch = o->branch1;
1125                         mode = b_mode;
1126                         sha = b_sha;
1127                         conf = "directory/file";
1128                 }
1129                 if (string_list_has_string(&o->current_directory_set, path)) {
1130                         const char *new_path = unique_path(o, path, add_branch);
1131                         clean_merge = 0;
1132                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1133                                "Adding %s as %s",
1134                                conf, path, other_branch, path, new_path);
1135                         remove_file(o, 0, path, 0);
1136                         update_file(o, 0, sha, mode, new_path);
1137                 } else {
1138                         output(o, 2, "Adding %s", path);
1139                         update_file(o, 1, sha, mode, path);
1140                 }
1141         } else if (a_sha && b_sha) {
1142                 /* Case C: Added in both (check for same permissions) and */
1143                 /* case D: Modified in both, but differently. */
1144                 const char *reason = "content";
1145                 struct merge_file_info mfi;
1146                 struct diff_filespec one, a, b;
1147
1148                 if (!o_sha) {
1149                         reason = "add/add";
1150                         o_sha = (unsigned char *)null_sha1;
1151                 }
1152                 output(o, 2, "Auto-merging %s", path);
1153                 one.path = a.path = b.path = (char *)path;
1154                 hashcpy(one.sha1, o_sha);
1155                 one.mode = o_mode;
1156                 hashcpy(a.sha1, a_sha);
1157                 a.mode = a_mode;
1158                 hashcpy(b.sha1, b_sha);
1159                 b.mode = b_mode;
1160
1161                 mfi = merge_file(o, &one, &a, &b,
1162                                  o->branch1, o->branch2);
1163
1164                 clean_merge = mfi.clean;
1165                 if (!mfi.clean) {
1166                         if (S_ISGITLINK(mfi.mode))
1167                                 reason = "submodule";
1168                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1169                                         reason, path);
1170                 }
1171                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1172         } else if (!o_sha && !a_sha && !b_sha) {
1173                 /*
1174                  * this entry was deleted altogether. a_mode == 0 means
1175                  * we had that path and want to actively remove it.
1176                  */
1177                 remove_file(o, 1, path, !a_mode);
1178         } else
1179                 die("Fatal merge failure, shouldn't happen.");
1180
1181         return clean_merge;
1182 }
1183
1184 struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
1185 {
1186         struct unpack_trees_error_msgs msgs = {
1187                 /* would_overwrite */
1188                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1189                 /* not_uptodate_file */
1190                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1191                 /* not_uptodate_dir */
1192                 "Updating '%s' would lose untracked files in it.  Aborting.",
1193                 /* would_lose_untracked */
1194                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
1195                 /* bind_overlap -- will not happen here */
1196                 NULL,
1197         };
1198         if (advice_commit_before_merge) {
1199                 msgs.would_overwrite = msgs.not_uptodate_file =
1200                         "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
1201                         "Please, commit your changes or stash them before you can merge.";
1202         }
1203         return msgs;
1204 }
1205
1206 int merge_trees(struct merge_options *o,
1207                 struct tree *head,
1208                 struct tree *merge,
1209                 struct tree *common,
1210                 struct tree **result)
1211 {
1212         int code, clean;
1213
1214         if (o->subtree_shift) {
1215                 merge = shift_tree_object(head, merge, o->subtree_shift);
1216                 common = shift_tree_object(head, common, o->subtree_shift);
1217         }
1218
1219         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1220                 output(o, 0, "Already uptodate!");
1221                 *result = head;
1222                 return 1;
1223         }
1224
1225         code = git_merge_trees(o->call_depth, common, head, merge);
1226
1227         if (code != 0) {
1228                 if (show(o, 4) || o->call_depth)
1229                         die("merging of trees %s and %s failed",
1230                             sha1_to_hex(head->object.sha1),
1231                             sha1_to_hex(merge->object.sha1));
1232                 else
1233                         exit(128);
1234         }
1235
1236         if (unmerged_cache()) {
1237                 struct string_list *entries, *re_head, *re_merge;
1238                 int i;
1239                 string_list_clear(&o->current_file_set, 1);
1240                 string_list_clear(&o->current_directory_set, 1);
1241                 get_files_dirs(o, head);
1242                 get_files_dirs(o, merge);
1243
1244                 entries = get_unmerged();
1245                 re_head  = get_renames(o, head, common, head, merge, entries);
1246                 re_merge = get_renames(o, merge, common, head, merge, entries);
1247                 clean = process_renames(o, re_head, re_merge);
1248                 for (i = 0; i < entries->nr; i++) {
1249                         const char *path = entries->items[i].string;
1250                         struct stage_data *e = entries->items[i].util;
1251                         if (!e->processed
1252                                 && !process_entry(o, path, e))
1253                                 clean = 0;
1254                 }
1255
1256                 string_list_clear(re_merge, 0);
1257                 string_list_clear(re_head, 0);
1258                 string_list_clear(entries, 1);
1259
1260         }
1261         else
1262                 clean = 1;
1263
1264         if (o->call_depth)
1265                 *result = write_tree_from_memory(o);
1266
1267         return clean;
1268 }
1269
1270 static struct commit_list *reverse_commit_list(struct commit_list *list)
1271 {
1272         struct commit_list *next = NULL, *current, *backup;
1273         for (current = list; current; current = backup) {
1274                 backup = current->next;
1275                 current->next = next;
1276                 next = current;
1277         }
1278         return next;
1279 }
1280
1281 /*
1282  * Merge the commits h1 and h2, return the resulting virtual
1283  * commit object and a flag indicating the cleanness of the merge.
1284  */
1285 int merge_recursive(struct merge_options *o,
1286                     struct commit *h1,
1287                     struct commit *h2,
1288                     struct commit_list *ca,
1289                     struct commit **result)
1290 {
1291         struct commit_list *iter;
1292         struct commit *merged_common_ancestors;
1293         struct tree *mrtree = mrtree;
1294         int clean;
1295
1296         if (show(o, 4)) {
1297                 output(o, 4, "Merging:");
1298                 output_commit_title(o, h1);
1299                 output_commit_title(o, h2);
1300         }
1301
1302         if (!ca) {
1303                 ca = get_merge_bases(h1, h2, 1);
1304                 ca = reverse_commit_list(ca);
1305         }
1306
1307         if (show(o, 5)) {
1308                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1309                 for (iter = ca; iter; iter = iter->next)
1310                         output_commit_title(o, iter->item);
1311         }
1312
1313         merged_common_ancestors = pop_commit(&ca);
1314         if (merged_common_ancestors == NULL) {
1315                 /* if there is no common ancestor, make an empty tree */
1316                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1317
1318                 tree->object.parsed = 1;
1319                 tree->object.type = OBJ_TREE;
1320                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1321                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1322         }
1323
1324         for (iter = ca; iter; iter = iter->next) {
1325                 const char *saved_b1, *saved_b2;
1326                 o->call_depth++;
1327                 /*
1328                  * When the merge fails, the result contains files
1329                  * with conflict markers. The cleanness flag is
1330                  * ignored, it was never actually used, as result of
1331                  * merge_trees has always overwritten it: the committed
1332                  * "conflicts" were already resolved.
1333                  */
1334                 discard_cache();
1335                 saved_b1 = o->branch1;
1336                 saved_b2 = o->branch2;
1337                 o->branch1 = "Temporary merge branch 1";
1338                 o->branch2 = "Temporary merge branch 2";
1339                 merge_recursive(o, merged_common_ancestors, iter->item,
1340                                 NULL, &merged_common_ancestors);
1341                 o->branch1 = saved_b1;
1342                 o->branch2 = saved_b2;
1343                 o->call_depth--;
1344
1345                 if (!merged_common_ancestors)
1346                         die("merge returned no commit");
1347         }
1348
1349         discard_cache();
1350         if (!o->call_depth)
1351                 read_cache();
1352
1353         o->ancestor = "merged common ancestors";
1354         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1355                             &mrtree);
1356
1357         if (o->call_depth) {
1358                 *result = make_virtual_commit(mrtree, "merged tree");
1359                 commit_list_insert(h1, &(*result)->parents);
1360                 commit_list_insert(h2, &(*result)->parents->next);
1361         }
1362         flush_output(o);
1363         return clean;
1364 }
1365
1366 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1367 {
1368         struct object *object;
1369
1370         object = deref_tag(parse_object(sha1), name, strlen(name));
1371         if (!object)
1372                 return NULL;
1373         if (object->type == OBJ_TREE)
1374                 return make_virtual_commit((struct tree*)object, name);
1375         if (object->type != OBJ_COMMIT)
1376                 return NULL;
1377         if (parse_commit((struct commit *)object))
1378                 return NULL;
1379         return (struct commit *)object;
1380 }
1381
1382 int merge_recursive_generic(struct merge_options *o,
1383                             const unsigned char *head,
1384                             const unsigned char *merge,
1385                             int num_base_list,
1386                             const unsigned char **base_list,
1387                             struct commit **result)
1388 {
1389         int clean, index_fd;
1390         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1391         struct commit *head_commit = get_ref(head, o->branch1);
1392         struct commit *next_commit = get_ref(merge, o->branch2);
1393         struct commit_list *ca = NULL;
1394
1395         if (base_list) {
1396                 int i;
1397                 for (i = 0; i < num_base_list; ++i) {
1398                         struct commit *base;
1399                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1400                                 return error("Could not parse object '%s'",
1401                                         sha1_to_hex(base_list[i]));
1402                         commit_list_insert(base, &ca);
1403                 }
1404         }
1405
1406         index_fd = hold_locked_index(lock, 1);
1407         clean = merge_recursive(o, head_commit, next_commit, ca,
1408                         result);
1409         if (active_cache_changed &&
1410                         (write_cache(index_fd, active_cache, active_nr) ||
1411                          commit_locked_index(lock)))
1412                 return error("Unable to write index.");
1413
1414         return clean ? 0 : 1;
1415 }
1416
1417 static int merge_recursive_config(const char *var, const char *value, void *cb)
1418 {
1419         struct merge_options *o = cb;
1420         if (!strcasecmp(var, "merge.verbosity")) {
1421                 o->verbosity = git_config_int(var, value);
1422                 return 0;
1423         }
1424         if (!strcasecmp(var, "diff.renamelimit")) {
1425                 o->diff_rename_limit = git_config_int(var, value);
1426                 return 0;
1427         }
1428         if (!strcasecmp(var, "merge.renamelimit")) {
1429                 o->merge_rename_limit = git_config_int(var, value);
1430                 return 0;
1431         }
1432         return git_xmerge_config(var, value, cb);
1433 }
1434
1435 void init_merge_options(struct merge_options *o)
1436 {
1437         memset(o, 0, sizeof(struct merge_options));
1438         o->verbosity = 2;
1439         o->buffer_output = 1;
1440         o->diff_rename_limit = -1;
1441         o->merge_rename_limit = -1;
1442         git_config(merge_recursive_config, o);
1443         if (getenv("GIT_MERGE_VERBOSITY"))
1444                 o->verbosity =
1445                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1446         if (o->verbosity >= 5)
1447                 o->buffer_output = 0;
1448         strbuf_init(&o->obuf, 0);
1449         memset(&o->current_file_set, 0, sizeof(struct string_list));
1450         o->current_file_set.strdup_strings = 1;
1451         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1452         o->current_directory_set.strdup_strings = 1;
1453 }