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         struct unpack_trees_error_msgs msgs = {
 178                 /* would_overwrite */
 179                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
 180                 /* not_uptodate_file */
 181                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
 182                 /* not_uptodate_dir */
 183                 "Updating '%s' would lose untracked files in it.  Aborting.",
 184                 /* would_lose_untracked */
 185                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
 186                 /* bind_overlap -- will not happen here */
 187                 NULL,
 188         };
 189         if (advice_commit_before_merge) {
 190                 msgs.would_overwrite = msgs.not_uptodate_file =
 191                         "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
 192                         "Please, commit your changes or stash them before you can merge.";
 193         }
 194
 195         memset(&opts, 0, sizeof(opts));
 196         if (index_only)
 197                 opts.index_only = 1;
 198         else
 199                 opts.update = 1;
 200         opts.merge = 1;
 201         opts.head_idx = 2;
 202         opts.fn = threeway_merge;
 203         opts.src_index = &the_index;
 204         opts.dst_index = &the_index;
 205         opts.msgs = msgs;
 206
 207         init_tree_desc_from_tree(t+0, common);
 208         init_tree_desc_from_tree(t+1, head);
 209         init_tree_desc_from_tree(t+2, merge);
 210
 211         rc = unpack_trees(3, t, &opts);
 212         cache_tree_free(&active_cache_tree);
 213         return rc;
 214 }
 215
 216 struct tree *write_tree_from_memory(struct merge_options *o)
 217 {
 218         struct tree *result = NULL;
 219
 220         if (unmerged_cache()) {
 221                 int i;
 222                 output(o, 0, "There are unmerged index entries:");
 223                 for (i = 0; i < active_nr; i++) {
 224                         struct cache_entry *ce = active_cache[i];
 225                         if (ce_stage(ce))
 226                                 output(o, 0, "%d %.*s", ce_stage(ce),
 227                                        (int)ce_namelen(ce), ce->name);
 228                 }
 229                 return NULL;
 230         }
 231
 232         if (!active_cache_tree)
 233                 active_cache_tree = cache_tree();
 234
 235         if (!cache_tree_fully_valid(active_cache_tree) &&
 236             cache_tree_update(active_cache_tree,
 237                               active_cache, active_nr, 0, 0) < 0)
 238                 die("error building trees");
 239
 240         result = lookup_tree(active_cache_tree->sha1);
 241
 242         return result;
 243 }
 244
 245 static int save_files_dirs(const unsigned char *sha1,
 246                 const char *base, int baselen, const char *path,
 247                 unsigned int mode, int stage, void *context)
 248 {
 249         int len = strlen(path);
 250         char *newpath = xmalloc(baselen + len + 1);
 251         struct merge_options *o = context;
 252
 253         memcpy(newpath, base, baselen);
 254         memcpy(newpath + baselen, path, len);
 255         newpath[baselen + len] = '\0';
 256
 257         if (S_ISDIR(mode))
 258                 string_list_insert(newpath, &o->current_directory_set);
 259         else
 260                 string_list_insert(newpath, &o->current_file_set);
 261         free(newpath);
 262
 263         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 264 }
 265
 266 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 267 {
 268         int n;
 269         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 270                 return 0;
 271         n = o->current_file_set.nr + o->current_directory_set.nr;
 272         return n;
 273 }
 274
 275 /*
 276  * Returns an index_entry instance which doesn't have to correspond to
 277  * a real cache entry in Git's index.
 278  */
 279 static struct stage_data *insert_stage_data(const char *path,
 280                 struct tree *o, struct tree *a, struct tree *b,
 281                 struct string_list *entries)
 282 {
 283         struct string_list_item *item;
 284         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 285         get_tree_entry(o->object.sha1, path,
 286                         e->stages[1].sha, &e->stages[1].mode);
 287         get_tree_entry(a->object.sha1, path,
 288                         e->stages[2].sha, &e->stages[2].mode);
 289         get_tree_entry(b->object.sha1, path,
 290                         e->stages[3].sha, &e->stages[3].mode);
 291         item = string_list_insert(path, entries);
 292         item->util = e;
 293         return e;
 294 }
 295
 296 /*
 297  * Create a dictionary mapping file names to stage_data objects. The
 298  * dictionary contains one entry for every path with a non-zero stage entry.
 299  */
 300 static struct string_list *get_unmerged(void)
 301 {
 302         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 303         int i;
 304
 305         unmerged->strdup_strings = 1;
 306
 307         for (i = 0; i < active_nr; i++) {
 308                 struct string_list_item *item;
 309                 struct stage_data *e;
 310                 struct cache_entry *ce = active_cache[i];
 311                 if (!ce_stage(ce))
 312                         continue;
 313
 314                 item = string_list_lookup(ce->name, unmerged);
 315                 if (!item) {
 316                         item = string_list_insert(ce->name, unmerged);
 317                         item->util = xcalloc(1, sizeof(struct stage_data));
 318                 }
 319                 e = item->util;
 320                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 321                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 322         }
 323
 324         return unmerged;
 325 }
 326
 327 struct rename
 328 {
 329         struct diff_filepair *pair;
 330         struct stage_data *src_entry;
 331         struct stage_data *dst_entry;
 332         unsigned processed:1;
 333 };
 334
 335 /*
 336  * Get information of all renames which occurred between 'o_tree' and
 337  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 338  * 'b_tree') to be able to associate the correct cache entries with
 339  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 340  */
 341 static struct string_list *get_renames(struct merge_options *o,
 342                                        struct tree *tree,
 343                                        struct tree *o_tree,
 344                                        struct tree *a_tree,
 345                                        struct tree *b_tree,
 346                                        struct string_list *entries)
 347 {
 348         int i;
 349         struct string_list *renames;
 350         struct diff_options opts;
 351
 352         renames = xcalloc(1, sizeof(struct string_list));
 353         diff_setup(&opts);
 354         DIFF_OPT_SET(&opts, RECURSIVE);
 355         opts.detect_rename = DIFF_DETECT_RENAME;
 356         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 357                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 358                             500;
 359         opts.warn_on_too_large_rename = 1;
 360         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 361         if (diff_setup_done(&opts) < 0)
 362                 die("diff setup failed");
 363         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 364         diffcore_std(&opts);
 365         for (i = 0; i < diff_queued_diff.nr; ++i) {
 366                 struct string_list_item *item;
 367                 struct rename *re;
 368                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 369                 if (pair->status != 'R') {
 370                         diff_free_filepair(pair);
 371                         continue;
 372                 }
 373                 re = xmalloc(sizeof(*re));
 374                 re->processed = 0;
 375                 re->pair = pair;
 376                 item = string_list_lookup(re->pair->one->path, entries);
 377                 if (!item)
 378                         re->src_entry = insert_stage_data(re->pair->one->path,
 379                                         o_tree, a_tree, b_tree, entries);
 380                 else
 381                         re->src_entry = item->util;
 382
 383                 item = string_list_lookup(re->pair->two->path, entries);
 384                 if (!item)
 385                         re->dst_entry = insert_stage_data(re->pair->two->path,
 386                                         o_tree, a_tree, b_tree, entries);
 387                 else
 388                         re->dst_entry = item->util;
 389                 item = string_list_insert(pair->one->path, renames);
 390                 item->util = re;
 391         }
 392         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 393         diff_queued_diff.nr = 0;
 394         diff_flush(&opts);
 395         return renames;
 396 }
 397
 398 static int update_stages(const char *path, struct diff_filespec *o,
 399                          struct diff_filespec *a, struct diff_filespec *b,
 400                          int clear)
 401 {
 402         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 403         if (clear)
 404                 if (remove_file_from_cache(path))
 405                         return -1;
 406         if (o)
 407                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 408                         return -1;
 409         if (a)
 410                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 411                         return -1;
 412         if (b)
 413                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 414                         return -1;
 415         return 0;
 416 }
 417
 418 static int remove_file(struct merge_options *o, int clean,
 419                        const char *path, int no_wd)
 420 {
 421         int update_cache = o->call_depth || clean;
 422         int update_working_directory = !o->call_depth && !no_wd;
 423
 424         if (update_cache) {
 425                 if (remove_file_from_cache(path))
 426                         return -1;
 427         }
 428         if (update_working_directory) {
 429                 if (remove_path(path) && errno != ENOENT)
 430                         return -1;
 431         }
 432         return 0;
 433 }
 434
 435 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 436 {
 437         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 438         int suffix = 0;
 439         struct stat st;
 440         char *p = newpath + strlen(path);
 441         strcpy(newpath, path);
 442         *(p++) = '~';
 443         strcpy(p, branch);
 444         for (; *p; ++p)
 445                 if ('/' == *p)
 446                         *p = '_';
 447         while (string_list_has_string(&o->current_file_set, newpath) ||
 448                string_list_has_string(&o->current_directory_set, newpath) ||
 449                lstat(newpath, &st) == 0)
 450                 sprintf(p, "_%d", suffix++);
 451
 452         string_list_insert(newpath, &o->current_file_set);
 453         return newpath;
 454 }
 455
 456 static void flush_buffer(int fd, const char *buf, unsigned long size)
 457 {
 458         while (size > 0) {
 459                 long ret = write_in_full(fd, buf, size);
 460                 if (ret < 0) {
 461                         /* Ignore epipe */
 462                         if (errno == EPIPE)
 463                                 break;
 464                         die_errno("merge-recursive");
 465                 } else if (!ret) {
 466                         die("merge-recursive: disk full?");
 467                 }
 468                 size -= ret;
 469                 buf += ret;
 470         }
 471 }
 472
 473 static int would_lose_untracked(const char *path)
 474 {
 475         int pos = cache_name_pos(path, strlen(path));
 476
 477         if (pos < 0)
 478                 pos = -1 - pos;
 479         while (pos < active_nr &&
 480                !strcmp(path, active_cache[pos]->name)) {
 481                 /*
 482                  * If stage #0, it is definitely tracked.
 483                  * If it has stage #2 then it was tracked
 484                  * before this merge started.  All other
 485                  * cases the path was not tracked.
 486                  */
 487                 switch (ce_stage(active_cache[pos])) {
 488                 case 0:
 489                 case 2:
 490                         return 0;
 491                 }
 492                 pos++;
 493         }
 494         return file_exists(path);
 495 }
 496
 497 static int make_room_for_path(const char *path)
 498 {
 499         int status;
 500         const char *msg = "failed to create path '%s'%s";
 501
 502         status = safe_create_leading_directories_const(path);
 503         if (status) {
 504                 if (status == -3) {
 505                         /* something else exists */
 506                         error(msg, path, ": perhaps a D/F conflict?");
 507                         return -1;
 508                 }
 509                 die(msg, path, "");
 510         }
 511
 512         /*
 513          * Do not unlink a file in the work tree if we are not
 514          * tracking it.
 515          */
 516         if (would_lose_untracked(path))
 517                 return error("refusing to lose untracked file at '%s'",
 518                              path);
 519
 520         /* Successful unlink is good.. */
 521         if (!unlink(path))
 522                 return 0;
 523         /* .. and so is no existing file */
 524         if (errno == ENOENT)
 525                 return 0;
 526         /* .. but not some other error (who really cares what?) */
 527         return error(msg, path, ": perhaps a D/F conflict?");
 528 }
 529
 530 static void update_file_flags(struct merge_options *o,
 531                               const unsigned char *sha,
 532                               unsigned mode,
 533                               const char *path,
 534                               int update_cache,
 535                               int update_wd)
 536 {
 537         if (o->call_depth)
 538                 update_wd = 0;
 539
 540         if (update_wd) {
 541                 enum object_type type;
 542                 void *buf;
 543                 unsigned long size;
 544
 545                 if (S_ISGITLINK(mode))
 546                         /*
 547                          * We may later decide to recursively descend into
 548                          * the submodule directory and update its index
 549                          * and/or work tree, but we do not do that now.
 550                          */
 551                         goto update_index;
 552
 553                 buf = read_sha1_file(sha, &type, &size);
 554                 if (!buf)
 555                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 556                 if (type != OBJ_BLOB)
 557                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 558                 if (S_ISREG(mode)) {
 559                         struct strbuf strbuf = STRBUF_INIT;
 560                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 561                                 free(buf);
 562                                 size = strbuf.len;
 563                                 buf = strbuf_detach(&strbuf, NULL);
 564                         }
 565                 }
 566
 567                 if (make_room_for_path(path) < 0) {
 568                         update_wd = 0;
 569                         free(buf);
 570                         goto update_index;
 571                 }
 572                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 573                         int fd;
 574                         if (mode & 0100)
 575                                 mode = 0777;
 576                         else
 577                                 mode = 0666;
 578                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 579                         if (fd < 0)
 580                                 die_errno("failed to open '%s'", path);
 581                         flush_buffer(fd, buf, size);
 582                         close(fd);
 583                 } else if (S_ISLNK(mode)) {
 584                         char *lnk = xmemdupz(buf, size);
 585                         safe_create_leading_directories_const(path);
 586                         unlink(path);
 587                         if (symlink(lnk, path))
 588                                 die_errno("failed to symlink '%s'", path);
 589                         free(lnk);
 590                 } else
 591                         die("do not know what to do with %06o %s '%s'",
 592                             mode, sha1_to_hex(sha), path);
 593                 free(buf);
 594         }
 595  update_index:
 596         if (update_cache)
 597                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 598 }
 599
 600 static void update_file(struct merge_options *o,
 601                         int clean,
 602                         const unsigned char *sha,
 603                         unsigned mode,
 604                         const char *path)
 605 {
 606         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 607 }
 608
 609 /* Low level file merging, update and removal */
 610
 611 struct merge_file_info
 612 {
 613         unsigned char sha[20];
 614         unsigned mode;
 615         unsigned clean:1,
 616                  merge:1;
 617 };
 618
 619 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 620 {
 621         unsigned long size;
 622         enum object_type type;
 623
 624         if (!hashcmp(sha1, null_sha1)) {
 625                 mm->ptr = xstrdup("");
 626                 mm->size = 0;
 627                 return;
 628         }
 629
 630         mm->ptr = read_sha1_file(sha1, &type, &size);
 631         if (!mm->ptr || type != OBJ_BLOB)
 632                 die("unable to read blob object %s", sha1_to_hex(sha1));
 633         mm->size = size;
 634 }
 635
 636 static int merge_3way(struct merge_options *o,
 637                       mmbuffer_t *result_buf,
 638                       struct diff_filespec *one,
 639                       struct diff_filespec *a,
 640                       struct diff_filespec *b,
 641                       const char *branch1,
 642                       const char *branch2)
 643 {
 644         mmfile_t orig, src1, src2;
 645         char *name1, *name2;
 646         int merge_status;
 647         int favor;
 648
 649         if (o->call_depth)
 650                 favor = 0;
 651         else {
 652                 switch (o->recursive_variant) {
 653                 case MERGE_RECURSIVE_OURS:
 654                         favor = XDL_MERGE_FAVOR_OURS;
 655                         break;
 656                 case MERGE_RECURSIVE_THEIRS:
 657                         favor = XDL_MERGE_FAVOR_THEIRS;
 658                         break;
 659                 default:
 660                         favor = 0;
 661                         break;
 662                 }
 663         }
 664
 665         if (strcmp(a->path, b->path)) {
 666                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 667                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 668         } else {
 669                 name1 = xstrdup(mkpath("%s", branch1));
 670                 name2 = xstrdup(mkpath("%s", branch2));
 671         }
 672
 673         fill_mm(one->sha1, &orig);
 674         fill_mm(a->sha1, &src1);
 675         fill_mm(b->sha1, &src2);
 676
 677         merge_status = ll_merge(result_buf, a->path, &orig,
 678                                 &src1, name1, &src2, name2,
 679                                 (!!o->call_depth) | (favor << 1));
 680
 681         free(name1);
 682         free(name2);
 683         free(orig.ptr);
 684         free(src1.ptr);
 685         free(src2.ptr);
 686         return merge_status;
 687 }
 688
 689 static struct merge_file_info merge_file(struct merge_options *o,
 690                                          struct diff_filespec *one,
 691                                          struct diff_filespec *a,
 692                                          struct diff_filespec *b,
 693                                          const char *branch1,
 694                                          const char *branch2)
 695 {
 696         struct merge_file_info result;
 697         result.merge = 0;
 698         result.clean = 1;
 699
 700         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 701                 result.clean = 0;
 702                 if (S_ISREG(a->mode)) {
 703                         result.mode = a->mode;
 704                         hashcpy(result.sha, a->sha1);
 705                 } else {
 706                         result.mode = b->mode;
 707                         hashcpy(result.sha, b->sha1);
 708                 }
 709         } else {
 710                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 711                         result.merge = 1;
 712
 713                 /*
 714                  * Merge modes
 715                  */
 716                 if (a->mode == b->mode || a->mode == one->mode)
 717                         result.mode = b->mode;
 718                 else {
 719                         result.mode = a->mode;
 720                         if (b->mode != one->mode) {
 721                                 result.clean = 0;
 722                                 result.merge = 1;
 723                         }
 724                 }
 725
 726                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 727                         hashcpy(result.sha, b->sha1);
 728                 else if (sha_eq(b->sha1, one->sha1))
 729                         hashcpy(result.sha, a->sha1);
 730                 else if (S_ISREG(a->mode)) {
 731                         mmbuffer_t result_buf;
 732                         int merge_status;
 733
 734                         merge_status = merge_3way(o, &result_buf, one, a, b,
 735                                                   branch1, branch2);
 736
 737                         if ((merge_status < 0) || !result_buf.ptr)
 738                                 die("Failed to execute internal merge");
 739
 740                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 741                                             blob_type, result.sha))
 742                                 die("Unable to add %s to database",
 743                                     a->path);
 744
 745                         free(result_buf.ptr);
 746                         result.clean = (merge_status == 0);
 747                 } else if (S_ISGITLINK(a->mode)) {
 748                         result.clean = 0;
 749                         hashcpy(result.sha, a->sha1);
 750                 } else if (S_ISLNK(a->mode)) {
 751                         hashcpy(result.sha, a->sha1);
 752
 753                         if (!sha_eq(a->sha1, b->sha1))
 754                                 result.clean = 0;
 755                 } else {
 756                         die("unsupported object type in the tree");
 757                 }
 758         }
 759
 760         return result;
 761 }
 762
 763 static void conflict_rename_rename(struct merge_options *o,
 764                                    struct rename *ren1,
 765                                    const char *branch1,
 766                                    struct rename *ren2,
 767                                    const char *branch2)
 768 {
 769         char *del[2];
 770         int delp = 0;
 771         const char *ren1_dst = ren1->pair->two->path;
 772         const char *ren2_dst = ren2->pair->two->path;
 773         const char *dst_name1 = ren1_dst;
 774         const char *dst_name2 = ren2_dst;
 775         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 776                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 777                 output(o, 1, "%s is a directory in %s adding as %s instead",
 778                        ren1_dst, branch2, dst_name1);
 779                 remove_file(o, 0, ren1_dst, 0);
 780         }
 781         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 782                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 783                 output(o, 1, "%s is a directory in %s adding as %s instead",
 784                        ren2_dst, branch1, dst_name2);
 785                 remove_file(o, 0, ren2_dst, 0);
 786         }
 787         if (o->call_depth) {
 788                 remove_file_from_cache(dst_name1);
 789                 remove_file_from_cache(dst_name2);
 790                 /*
 791                  * Uncomment to leave the conflicting names in the resulting tree
 792                  *
 793                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 794                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 795                  */
 796         } else {
 797                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 798                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 799         }
 800         while (delp--)
 801                 free(del[delp]);
 802 }
 803
 804 static void conflict_rename_dir(struct merge_options *o,
 805                                 struct rename *ren1,
 806                                 const char *branch1)
 807 {
 808         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 809         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 810         remove_file(o, 0, ren1->pair->two->path, 0);
 811         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 812         free(new_path);
 813 }
 814
 815 static void conflict_rename_rename_2(struct merge_options *o,
 816                                      struct rename *ren1,
 817                                      const char *branch1,
 818                                      struct rename *ren2,
 819                                      const char *branch2)
 820 {
 821         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 822         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 823         output(o, 1, "Renaming %s to %s and %s to %s instead",
 824                ren1->pair->one->path, new_path1,
 825                ren2->pair->one->path, new_path2);
 826         remove_file(o, 0, ren1->pair->two->path, 0);
 827         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 828         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 829         free(new_path2);
 830         free(new_path1);
 831 }
 832
 833 static int process_renames(struct merge_options *o,
 834                            struct string_list *a_renames,
 835                            struct string_list *b_renames)
 836 {
 837         int clean_merge = 1, i, j;
 838         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 839         const struct rename *sre;
 840
 841         for (i = 0; i < a_renames->nr; i++) {
 842                 sre = a_renames->items[i].util;
 843                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 844                         = sre->dst_entry;
 845         }
 846         for (i = 0; i < b_renames->nr; i++) {
 847                 sre = b_renames->items[i].util;
 848                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 849                         = sre->dst_entry;
 850         }
 851
 852         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 853                 char *src;
 854                 struct string_list *renames1, *renames2Dst;
 855                 struct rename *ren1 = NULL, *ren2 = NULL;
 856                 const char *branch1, *branch2;
 857                 const char *ren1_src, *ren1_dst;
 858
 859                 if (i >= a_renames->nr) {
 860                         ren2 = b_renames->items[j++].util;
 861                 } else if (j >= b_renames->nr) {
 862                         ren1 = a_renames->items[i++].util;
 863                 } else {
 864                         int compare = strcmp(a_renames->items[i].string,
 865                                              b_renames->items[j].string);
 866                         if (compare <= 0)
 867                                 ren1 = a_renames->items[i++].util;
 868                         if (compare >= 0)
 869                                 ren2 = b_renames->items[j++].util;
 870                 }
 871
 872                 /* TODO: refactor, so that 1/2 are not needed */
 873                 if (ren1) {
 874                         renames1 = a_renames;
 875                         renames2Dst = &b_by_dst;
 876                         branch1 = o->branch1;
 877                         branch2 = o->branch2;
 878                 } else {
 879                         struct rename *tmp;
 880                         renames1 = b_renames;
 881                         renames2Dst = &a_by_dst;
 882                         branch1 = o->branch2;
 883                         branch2 = o->branch1;
 884                         tmp = ren2;
 885                         ren2 = ren1;
 886                         ren1 = tmp;
 887                 }
 888                 src = ren1->pair->one->path;
 889
 890                 ren1->dst_entry->processed = 1;
 891                 ren1->src_entry->processed = 1;
 892
 893                 if (ren1->processed)
 894                         continue;
 895                 ren1->processed = 1;
 896
 897                 ren1_src = ren1->pair->one->path;
 898                 ren1_dst = ren1->pair->two->path;
 899
 900                 if (ren2) {
 901                         const char *ren2_src = ren2->pair->one->path;
 902                         const char *ren2_dst = ren2->pair->two->path;
 903                         /* Renamed in 1 and renamed in 2 */
 904                         if (strcmp(ren1_src, ren2_src) != 0)
 905                                 die("ren1.src != ren2.src");
 906                         ren2->dst_entry->processed = 1;
 907                         ren2->processed = 1;
 908                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 909                                 clean_merge = 0;
 910                                 output(o, 1, "CONFLICT (rename/rename): "
 911                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 912                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 913                                        src, ren1_dst, branch1,
 914                                        src, ren2_dst, branch2,
 915                                        o->call_depth ? " (left unresolved)": "");
 916                                 if (o->call_depth) {
 917                                         remove_file_from_cache(src);
 918                                         update_file(o, 0, ren1->pair->one->sha1,
 919                                                     ren1->pair->one->mode, src);
 920                                 }
 921                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 922                         } else {
 923                                 struct merge_file_info mfi;
 924                                 remove_file(o, 1, ren1_src, 1);
 925                                 mfi = merge_file(o,
 926                                                  ren1->pair->one,
 927                                                  ren1->pair->two,
 928                                                  ren2->pair->two,
 929                                                  branch1,
 930                                                  branch2);
 931                                 if (mfi.merge || !mfi.clean)
 932                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 933
 934                                 if (mfi.merge)
 935                                         output(o, 2, "Auto-merging %s", ren1_dst);
 936
 937                                 if (!mfi.clean) {
 938                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 939                                                ren1_dst);
 940                                         clean_merge = 0;
 941
 942                                         if (!o->call_depth)
 943                                                 update_stages(ren1_dst,
 944                                                               ren1->pair->one,
 945                                                               ren1->pair->two,
 946                                                               ren2->pair->two,
 947                                                               1 /* clear */);
 948                                 }
 949                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 950                         }
 951                 } else {
 952                         /* Renamed in 1, maybe changed in 2 */
 953                         struct string_list_item *item;
 954                         /* we only use sha1 and mode of these */
 955                         struct diff_filespec src_other, dst_other;
 956                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 957
 958                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 959
 960                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 961                         src_other.mode = ren1->src_entry->stages[stage].mode;
 962                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 963                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 964
 965                         try_merge = 0;
 966
 967                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 968                                 clean_merge = 0;
 969                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 970                                        " directory %s added in %s",
 971                                        ren1_src, ren1_dst, branch1,
 972                                        ren1_dst, branch2);
 973                                 conflict_rename_dir(o, ren1, branch1);
 974                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 975                                 clean_merge = 0;
 976                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 977                                        "and deleted in %s",
 978                                        ren1_src, ren1_dst, branch1,
 979                                        branch2);
 980                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 981                                 if (!o->call_depth)
 982                                         update_stages(ren1_dst, NULL,
 983                                                         branch1 == o->branch1 ?
 984                                                         ren1->pair->two : NULL,
 985                                                         branch1 == o->branch1 ?
 986                                                         NULL : ren1->pair->two, 1);
 987                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 988                                 const char *new_path;
 989                                 clean_merge = 0;
 990                                 try_merge = 1;
 991                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 992                                        "%s added in %s",
 993                                        ren1_src, ren1_dst, branch1,
 994                                        ren1_dst, branch2);
 995                                 if (o->call_depth) {
 996                                         struct merge_file_info mfi;
 997                                         struct diff_filespec one, a, b;
 998
 999                                         one.path = a.path = b.path =
1000                                                 (char *)ren1_dst;
1001                                         hashcpy(one.sha1, null_sha1);
1002                                         one.mode = 0;
1003                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1004                                         a.mode = ren1->pair->two->mode;
1005                                         hashcpy(b.sha1, dst_other.sha1);
1006                                         b.mode = dst_other.mode;
1007                                         mfi = merge_file(o, &one, &a, &b,
1008                                                          branch1,
1009                                                          branch2);
1010                                         output(o, 1, "Adding merged %s", ren1_dst);
1011                                         update_file(o, 0,
1012                                                     mfi.sha,
1013                                                     mfi.mode,
1014                                                     ren1_dst);
1015                                 } else {
1016                                         new_path = unique_path(o, ren1_dst, branch2);
1017                                         output(o, 1, "Adding as %s instead", new_path);
1018                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1019                                 }
1020                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
1021                                 ren2 = item->util;
1022                                 clean_merge = 0;
1023                                 ren2->processed = 1;
1024                                 output(o, 1, "CONFLICT (rename/rename): "
1025                                        "Rename %s->%s in %s. "
1026                                        "Rename %s->%s in %s",
1027                                        ren1_src, ren1_dst, branch1,
1028                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1029                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1030                         } else
1031                                 try_merge = 1;
1032
1033                         if (try_merge) {
1034                                 struct diff_filespec *one, *a, *b;
1035                                 struct merge_file_info mfi;
1036                                 src_other.path = (char *)ren1_src;
1037
1038                                 one = ren1->pair->one;
1039                                 if (a_renames == renames1) {
1040                                         a = ren1->pair->two;
1041                                         b = &src_other;
1042                                 } else {
1043                                         b = ren1->pair->two;
1044                                         a = &src_other;
1045                                 }
1046                                 mfi = merge_file(o, one, a, b,
1047                                                 o->branch1, o->branch2);
1048
1049                                 if (mfi.clean &&
1050                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1051                                     mfi.mode == ren1->pair->two->mode)
1052                                         /*
1053                                          * This messaged is part of
1054                                          * t6022 test. If you change
1055                                          * it update the test too.
1056                                          */
1057                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1058                                 else {
1059                                         if (mfi.merge || !mfi.clean)
1060                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1061                                         if (mfi.merge)
1062                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1063                                         if (!mfi.clean) {
1064                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1065                                                        ren1_dst);
1066                                                 clean_merge = 0;
1067
1068                                                 if (!o->call_depth)
1069                                                         update_stages(ren1_dst,
1070                                                                       one, a, b, 1);
1071                                         }
1072                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1073                                 }
1074                         }
1075                 }
1076         }
1077         string_list_clear(&a_by_dst, 0);
1078         string_list_clear(&b_by_dst, 0);
1079
1080         return clean_merge;
1081 }
1082
1083 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1084 {
1085         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1086 }
1087
1088 /* Per entry merge function */
1089 static int process_entry(struct merge_options *o,
1090                          const char *path, struct stage_data *entry)
1091 {
1092         /*
1093         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1094         print_index_entry("\tpath: ", entry);
1095         */
1096         int clean_merge = 1;
1097         unsigned o_mode = entry->stages[1].mode;
1098         unsigned a_mode = entry->stages[2].mode;
1099         unsigned b_mode = entry->stages[3].mode;
1100         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1101         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1102         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1103
1104         if (o_sha && (!a_sha || !b_sha)) {
1105                 /* Case A: Deleted in one */
1106                 if ((!a_sha && !b_sha) ||
1107                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1108                     (!a_sha && sha_eq(b_sha, o_sha))) {
1109                         /* Deleted in both or deleted in one and
1110                          * unchanged in the other */
1111                         if (a_sha)
1112                                 output(o, 2, "Removing %s", path);
1113                         /* do not touch working file if it did not exist */
1114                         remove_file(o, 1, path, !a_sha);
1115                 } else {
1116                         /* Deleted in one and changed in the other */
1117                         clean_merge = 0;
1118                         if (!a_sha) {
1119                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1120                                        "and modified in %s. Version %s of %s left in tree.",
1121                                        path, o->branch1,
1122                                        o->branch2, o->branch2, path);
1123                                 update_file(o, 0, b_sha, b_mode, path);
1124                         } else {
1125                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1126                                        "and modified in %s. Version %s of %s left in tree.",
1127                                        path, o->branch2,
1128                                        o->branch1, o->branch1, path);
1129                                 update_file(o, 0, a_sha, a_mode, path);
1130                         }
1131                 }
1132
1133         } else if ((!o_sha && a_sha && !b_sha) ||
1134                    (!o_sha && !a_sha && b_sha)) {
1135                 /* Case B: Added in one. */
1136                 const char *add_branch;
1137                 const char *other_branch;
1138                 unsigned mode;
1139                 const unsigned char *sha;
1140                 const char *conf;
1141
1142                 if (a_sha) {
1143                         add_branch = o->branch1;
1144                         other_branch = o->branch2;
1145                         mode = a_mode;
1146                         sha = a_sha;
1147                         conf = "file/directory";
1148                 } else {
1149                         add_branch = o->branch2;
1150                         other_branch = o->branch1;
1151                         mode = b_mode;
1152                         sha = b_sha;
1153                         conf = "directory/file";
1154                 }
1155                 if (string_list_has_string(&o->current_directory_set, path)) {
1156                         const char *new_path = unique_path(o, path, add_branch);
1157                         clean_merge = 0;
1158                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1159                                "Adding %s as %s",
1160                                conf, path, other_branch, path, new_path);
1161                         remove_file(o, 0, path, 0);
1162                         update_file(o, 0, sha, mode, new_path);
1163                 } else {
1164                         output(o, 2, "Adding %s", path);
1165                         update_file(o, 1, sha, mode, path);
1166                 }
1167         } else if (a_sha && b_sha) {
1168                 /* Case C: Added in both (check for same permissions) and */
1169                 /* case D: Modified in both, but differently. */
1170                 const char *reason = "content";
1171                 struct merge_file_info mfi;
1172                 struct diff_filespec one, a, b;
1173
1174                 if (!o_sha) {
1175                         reason = "add/add";
1176                         o_sha = (unsigned char *)null_sha1;
1177                 }
1178                 output(o, 2, "Auto-merging %s", path);
1179                 one.path = a.path = b.path = (char *)path;
1180                 hashcpy(one.sha1, o_sha);
1181                 one.mode = o_mode;
1182                 hashcpy(a.sha1, a_sha);
1183                 a.mode = a_mode;
1184                 hashcpy(b.sha1, b_sha);
1185                 b.mode = b_mode;
1186
1187                 mfi = merge_file(o, &one, &a, &b,
1188                                  o->branch1, o->branch2);
1189
1190                 clean_merge = mfi.clean;
1191                 if (!mfi.clean) {
1192                         if (S_ISGITLINK(mfi.mode))
1193                                 reason = "submodule";
1194                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1195                                         reason, path);
1196                 }
1197                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1198         } else if (!o_sha && !a_sha && !b_sha) {
1199                 /*
1200                  * this entry was deleted altogether. a_mode == 0 means
1201                  * we had that path and want to actively remove it.
1202                  */
1203                 remove_file(o, 1, path, !a_mode);
1204         } else
1205                 die("Fatal merge failure, shouldn't happen.");
1206
1207         return clean_merge;
1208 }
1209
1210 int merge_trees(struct merge_options *o,
1211                 struct tree *head,
1212                 struct tree *merge,
1213                 struct tree *common,
1214                 struct tree **result)
1215 {
1216         int code, clean;
1217
1218         if (o->subtree_shift) {
1219                 merge = shift_tree_object(head, merge, o->subtree_shift);
1220                 common = shift_tree_object(head, common, o->subtree_shift);
1221         }
1222
1223         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1224                 output(o, 0, "Already uptodate!");
1225                 *result = head;
1226                 return 1;
1227         }
1228
1229         code = git_merge_trees(o->call_depth, common, head, merge);
1230
1231         if (code != 0) {
1232                 if (show(o, 4) || o->call_depth)
1233                         die("merging of trees %s and %s failed",
1234                             sha1_to_hex(head->object.sha1),
1235                             sha1_to_hex(merge->object.sha1));
1236                 else
1237                         exit(128);
1238         }
1239
1240         if (unmerged_cache()) {
1241                 struct string_list *entries, *re_head, *re_merge;
1242                 int i;
1243                 string_list_clear(&o->current_file_set, 1);
1244                 string_list_clear(&o->current_directory_set, 1);
1245                 get_files_dirs(o, head);
1246                 get_files_dirs(o, merge);
1247
1248                 entries = get_unmerged();
1249                 re_head  = get_renames(o, head, common, head, merge, entries);
1250                 re_merge = get_renames(o, merge, common, head, merge, entries);
1251                 clean = process_renames(o, re_head, re_merge);
1252                 for (i = 0; i < entries->nr; i++) {
1253                         const char *path = entries->items[i].string;
1254                         struct stage_data *e = entries->items[i].util;
1255                         if (!e->processed
1256                                 && !process_entry(o, path, e))
1257                                 clean = 0;
1258                 }
1259
1260                 string_list_clear(re_merge, 0);
1261                 string_list_clear(re_head, 0);
1262                 string_list_clear(entries, 1);
1263
1264         }
1265         else
1266                 clean = 1;
1267
1268         if (o->call_depth)
1269                 *result = write_tree_from_memory(o);
1270
1271         return clean;
1272 }
1273
1274 static struct commit_list *reverse_commit_list(struct commit_list *list)
1275 {
1276         struct commit_list *next = NULL, *current, *backup;
1277         for (current = list; current; current = backup) {
1278                 backup = current->next;
1279                 current->next = next;
1280                 next = current;
1281         }
1282         return next;
1283 }
1284
1285 /*
1286  * Merge the commits h1 and h2, return the resulting virtual
1287  * commit object and a flag indicating the cleanness of the merge.
1288  */
1289 int merge_recursive(struct merge_options *o,
1290                     struct commit *h1,
1291                     struct commit *h2,
1292                     struct commit_list *ca,
1293                     struct commit **result)
1294 {
1295         struct commit_list *iter;
1296         struct commit *merged_common_ancestors;
1297         struct tree *mrtree = mrtree;
1298         int clean;
1299
1300         if (show(o, 4)) {
1301                 output(o, 4, "Merging:");
1302                 output_commit_title(o, h1);
1303                 output_commit_title(o, h2);
1304         }
1305
1306         if (!ca) {
1307                 ca = get_merge_bases(h1, h2, 1);
1308                 ca = reverse_commit_list(ca);
1309         }
1310
1311         if (show(o, 5)) {
1312                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1313                 for (iter = ca; iter; iter = iter->next)
1314                         output_commit_title(o, iter->item);
1315         }
1316
1317         merged_common_ancestors = pop_commit(&ca);
1318         if (merged_common_ancestors == NULL) {
1319                 /* if there is no common ancestor, make an empty tree */
1320                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1321
1322                 tree->object.parsed = 1;
1323                 tree->object.type = OBJ_TREE;
1324                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1325                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1326         }
1327
1328         for (iter = ca; iter; iter = iter->next) {
1329                 const char *saved_b1, *saved_b2;
1330                 o->call_depth++;
1331                 /*
1332                  * When the merge fails, the result contains files
1333                  * with conflict markers. The cleanness flag is
1334                  * ignored, it was never actually used, as result of
1335                  * merge_trees has always overwritten it: the committed
1336                  * "conflicts" were already resolved.
1337                  */
1338                 discard_cache();
1339                 saved_b1 = o->branch1;
1340                 saved_b2 = o->branch2;
1341                 o->branch1 = "Temporary merge branch 1";
1342                 o->branch2 = "Temporary merge branch 2";
1343                 merge_recursive(o, merged_common_ancestors, iter->item,
1344                                 NULL, &merged_common_ancestors);
1345                 o->branch1 = saved_b1;
1346                 o->branch2 = saved_b2;
1347                 o->call_depth--;
1348
1349                 if (!merged_common_ancestors)
1350                         die("merge returned no commit");
1351         }
1352
1353         discard_cache();
1354         if (!o->call_depth)
1355                 read_cache();
1356
1357         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1358                             &mrtree);
1359
1360         if (o->call_depth) {
1361                 *result = make_virtual_commit(mrtree, "merged tree");
1362                 commit_list_insert(h1, &(*result)->parents);
1363                 commit_list_insert(h2, &(*result)->parents->next);
1364         }
1365         flush_output(o);
1366         return clean;
1367 }
1368
1369 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1370 {
1371         struct object *object;
1372
1373         object = deref_tag(parse_object(sha1), name, strlen(name));
1374         if (!object)
1375                 return NULL;
1376         if (object->type == OBJ_TREE)
1377                 return make_virtual_commit((struct tree*)object, name);
1378         if (object->type != OBJ_COMMIT)
1379                 return NULL;
1380         if (parse_commit((struct commit *)object))
1381                 return NULL;
1382         return (struct commit *)object;
1383 }
1384
1385 int merge_recursive_generic(struct merge_options *o,
1386                             const unsigned char *head,
1387                             const unsigned char *merge,
1388                             int num_base_list,
1389                             const unsigned char **base_list,
1390                             struct commit **result)
1391 {
1392         int clean, index_fd;
1393         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1394         struct commit *head_commit = get_ref(head, o->branch1);
1395         struct commit *next_commit = get_ref(merge, o->branch2);
1396         struct commit_list *ca = NULL;
1397
1398         if (base_list) {
1399                 int i;
1400                 for (i = 0; i < num_base_list; ++i) {
1401                         struct commit *base;
1402                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1403                                 return error("Could not parse object '%s'",
1404                                         sha1_to_hex(base_list[i]));
1405                         commit_list_insert(base, &ca);
1406                 }
1407         }
1408
1409         index_fd = hold_locked_index(lock, 1);
1410         clean = merge_recursive(o, head_commit, next_commit, ca,
1411                         result);
1412         if (active_cache_changed &&
1413                         (write_cache(index_fd, active_cache, active_nr) ||
1414                          commit_locked_index(lock)))
1415                 return error("Unable to write index.");
1416
1417         return clean ? 0 : 1;
1418 }
1419
1420 static int merge_recursive_config(const char *var, const char *value, void *cb)
1421 {
1422         struct merge_options *o = cb;
1423         if (!strcasecmp(var, "merge.verbosity")) {
1424                 o->verbosity = git_config_int(var, value);
1425                 return 0;
1426         }
1427         if (!strcasecmp(var, "diff.renamelimit")) {
1428                 o->diff_rename_limit = git_config_int(var, value);
1429                 return 0;
1430         }
1431         if (!strcasecmp(var, "merge.renamelimit")) {
1432                 o->merge_rename_limit = git_config_int(var, value);
1433                 return 0;
1434         }
1435         return git_xmerge_config(var, value, cb);
1436 }
1437
1438 void init_merge_options(struct merge_options *o)
1439 {
1440         memset(o, 0, sizeof(struct merge_options));
1441         o->verbosity = 2;
1442         o->buffer_output = 1;
1443         o->diff_rename_limit = -1;
1444         o->merge_rename_limit = -1;
1445         git_config(merge_recursive_config, o);
1446         if (getenv("GIT_MERGE_VERBOSITY"))
1447                 o->verbosity =
1448                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1449         if (o->verbosity >= 5)
1450                 o->buffer_output = 0;
1451         strbuf_init(&o->obuf, 0);
1452         memset(&o->current_file_set, 0, sizeof(struct string_list));
1453         o->current_file_set.strdup_strings = 1;
1454         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1455         o->current_directory_set.strdup_strings = 1;
1456 }