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 enum rename_type {
  67         RENAME_NORMAL = 0,
  68         RENAME_DELETE,
  69         RENAME_ONE_FILE_TO_TWO
  70 };
  71
  72 struct rename_df_conflict_info {
  73         enum rename_type rename_type;
  74         struct diff_filepair *pair1;
  75         struct diff_filepair *pair2;
  76         const char *branch1;
  77         const char *branch2;
  78         struct stage_data *dst_entry1;
  79         struct stage_data *dst_entry2;
  80 };
  81
  82 /*
  83  * Since we want to write the index eventually, we cannot reuse the index
  84  * for these (temporary) data.
  85  */
  86 struct stage_data
  87 {
  88         struct
  89         {
  90                 unsigned mode;
  91                 unsigned char sha[20];
  92         } stages[4];
  93         struct rename_df_conflict_info *rename_df_conflict_info;
  94         unsigned processed:1;
  95 };
  96
  97 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
  98                                                  struct diff_filepair *pair1,
  99                                                  struct diff_filepair *pair2,
 100                                                  const char *branch1,
 101                                                  const char *branch2,
 102                                                  struct stage_data *dst_entry1,
 103                                                  struct stage_data *dst_entry2)
 104 {
 105         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
 106         ci->rename_type = rename_type;
 107         ci->pair1 = pair1;
 108         ci->branch1 = branch1;
 109         ci->branch2 = branch2;
 110
 111         ci->dst_entry1 = dst_entry1;
 112         dst_entry1->rename_df_conflict_info = ci;
 113         dst_entry1->processed = 0;
 114
 115         assert(!pair2 == !dst_entry2);
 116         if (dst_entry2) {
 117                 ci->dst_entry2 = dst_entry2;
 118                 ci->pair2 = pair2;
 119                 dst_entry2->rename_df_conflict_info = ci;
 120                 dst_entry2->processed = 0;
 121         }
 122 }
 123
 124 static int show(struct merge_options *o, int v)
 125 {
 126         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 127 }
 128
 129 static void flush_output(struct merge_options *o)
 130 {
 131         if (o->obuf.len) {
 132                 fputs(o->obuf.buf, stdout);
 133                 strbuf_reset(&o->obuf);
 134         }
 135 }
 136
 137 __attribute__((format (printf, 3, 4)))
 138 static void output(struct merge_options *o, int v, const char *fmt, ...)
 139 {
 140         int len;
 141         va_list ap;
 142
 143         if (!show(o, v))
 144                 return;
 145
 146         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 147         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 148         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 149
 150         va_start(ap, fmt);
 151         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 152         va_end(ap);
 153
 154         if (len < 0)
 155                 len = 0;
 156         if (len >= strbuf_avail(&o->obuf)) {
 157                 strbuf_grow(&o->obuf, len + 2);
 158                 va_start(ap, fmt);
 159                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 160                 va_end(ap);
 161                 if (len >= strbuf_avail(&o->obuf)) {
 162                         die("this should not happen, your snprintf is broken");
 163                 }
 164         }
 165         strbuf_setlen(&o->obuf, o->obuf.len + len);
 166         strbuf_add(&o->obuf, "\n", 1);
 167         if (!o->buffer_output)
 168                 flush_output(o);
 169 }
 170
 171 static void output_commit_title(struct merge_options *o, struct commit *commit)
 172 {
 173         int i;
 174         flush_output(o);
 175         for (i = o->call_depth; i--;)
 176                 fputs("  ", stdout);
 177         if (commit->util)
 178                 printf("virtual %s\n", (char *)commit->util);
 179         else {
 180                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 181                 if (parse_commit(commit) != 0)
 182                         printf("(bad commit)\n");
 183                 else {
 184                         const char *title;
 185                         int len = find_commit_subject(commit->buffer, &title);
 186                         if (len)
 187                                 printf("%.*s\n", len, title);
 188                 }
 189         }
 190 }
 191
 192 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 193                 const char *path, int stage, int refresh, int options)
 194 {
 195         struct cache_entry *ce;
 196         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 197         if (!ce)
 198                 return error("addinfo_cache failed for path '%s'", path);
 199         return add_cache_entry(ce, options);
 200 }
 201
 202 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 203 {
 204         parse_tree(tree);
 205         init_tree_desc(desc, tree->buffer, tree->size);
 206 }
 207
 208 static int git_merge_trees(int index_only,
 209                            struct tree *common,
 210                            struct tree *head,
 211                            struct tree *merge)
 212 {
 213         int rc;
 214         struct tree_desc t[3];
 215         struct unpack_trees_options opts;
 216
 217         memset(&opts, 0, sizeof(opts));
 218         if (index_only)
 219                 opts.index_only = 1;
 220         else
 221                 opts.update = 1;
 222         opts.merge = 1;
 223         opts.head_idx = 2;
 224         opts.fn = threeway_merge;
 225         opts.src_index = &the_index;
 226         opts.dst_index = &the_index;
 227         setup_unpack_trees_porcelain(&opts, "merge");
 228
 229         init_tree_desc_from_tree(t+0, common);
 230         init_tree_desc_from_tree(t+1, head);
 231         init_tree_desc_from_tree(t+2, merge);
 232
 233         rc = unpack_trees(3, t, &opts);
 234         cache_tree_free(&active_cache_tree);
 235         return rc;
 236 }
 237
 238 struct tree *write_tree_from_memory(struct merge_options *o)
 239 {
 240         struct tree *result = NULL;
 241
 242         if (unmerged_cache()) {
 243                 int i;
 244                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 245                 for (i = 0; i < active_nr; i++) {
 246                         struct cache_entry *ce = active_cache[i];
 247                         if (ce_stage(ce))
 248                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 249                                         (int)ce_namelen(ce), ce->name);
 250                 }
 251                 die("Bug in merge-recursive.c");
 252         }
 253
 254         if (!active_cache_tree)
 255                 active_cache_tree = cache_tree();
 256
 257         if (!cache_tree_fully_valid(active_cache_tree) &&
 258             cache_tree_update(active_cache_tree,
 259                               active_cache, active_nr, 0, 0) < 0)
 260                 die("error building trees");
 261
 262         result = lookup_tree(active_cache_tree->sha1);
 263
 264         return result;
 265 }
 266
 267 static int save_files_dirs(const unsigned char *sha1,
 268                 const char *base, int baselen, const char *path,
 269                 unsigned int mode, int stage, void *context)
 270 {
 271         int len = strlen(path);
 272         char *newpath = xmalloc(baselen + len + 1);
 273         struct merge_options *o = context;
 274
 275         memcpy(newpath, base, baselen);
 276         memcpy(newpath + baselen, path, len);
 277         newpath[baselen + len] = '\0';
 278
 279         if (S_ISDIR(mode))
 280                 string_list_insert(&o->current_directory_set, newpath);
 281         else
 282                 string_list_insert(&o->current_file_set, newpath);
 283         free(newpath);
 284
 285         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 286 }
 287
 288 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 289 {
 290         int n;
 291         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 292                 return 0;
 293         n = o->current_file_set.nr + o->current_directory_set.nr;
 294         return n;
 295 }
 296
 297 /*
 298  * Returns an index_entry instance which doesn't have to correspond to
 299  * a real cache entry in Git's index.
 300  */
 301 static struct stage_data *insert_stage_data(const char *path,
 302                 struct tree *o, struct tree *a, struct tree *b,
 303                 struct string_list *entries)
 304 {
 305         struct string_list_item *item;
 306         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 307         get_tree_entry(o->object.sha1, path,
 308                         e->stages[1].sha, &e->stages[1].mode);
 309         get_tree_entry(a->object.sha1, path,
 310                         e->stages[2].sha, &e->stages[2].mode);
 311         get_tree_entry(b->object.sha1, path,
 312                         e->stages[3].sha, &e->stages[3].mode);
 313         item = string_list_insert(entries, path);
 314         item->util = e;
 315         return e;
 316 }
 317
 318 /*
 319  * Create a dictionary mapping file names to stage_data objects. The
 320  * dictionary contains one entry for every path with a non-zero stage entry.
 321  */
 322 static struct string_list *get_unmerged(void)
 323 {
 324         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 325         int i;
 326
 327         unmerged->strdup_strings = 1;
 328
 329         for (i = 0; i < active_nr; i++) {
 330                 struct string_list_item *item;
 331                 struct stage_data *e;
 332                 struct cache_entry *ce = active_cache[i];
 333                 if (!ce_stage(ce))
 334                         continue;
 335
 336                 item = string_list_lookup(unmerged, ce->name);
 337                 if (!item) {
 338                         item = string_list_insert(unmerged, ce->name);
 339                         item->util = xcalloc(1, sizeof(struct stage_data));
 340                 }
 341                 e = item->util;
 342                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 343                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 344         }
 345
 346         return unmerged;
 347 }
 348
 349 struct rename
 350 {
 351         struct diff_filepair *pair;
 352         struct stage_data *src_entry;
 353         struct stage_data *dst_entry;
 354         unsigned processed:1;
 355 };
 356
 357 /*
 358  * Get information of all renames which occurred between 'o_tree' and
 359  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 360  * 'b_tree') to be able to associate the correct cache entries with
 361  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 362  */
 363 static struct string_list *get_renames(struct merge_options *o,
 364                                        struct tree *tree,
 365                                        struct tree *o_tree,
 366                                        struct tree *a_tree,
 367                                        struct tree *b_tree,
 368                                        struct string_list *entries)
 369 {
 370         int i;
 371         struct string_list *renames;
 372         struct diff_options opts;
 373
 374         renames = xcalloc(1, sizeof(struct string_list));
 375         diff_setup(&opts);
 376         DIFF_OPT_SET(&opts, RECURSIVE);
 377         opts.detect_rename = DIFF_DETECT_RENAME;
 378         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 379                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 380                             500;
 381         opts.warn_on_too_large_rename = 1;
 382         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 383         if (diff_setup_done(&opts) < 0)
 384                 die("diff setup failed");
 385         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 386         diffcore_std(&opts);
 387         for (i = 0; i < diff_queued_diff.nr; ++i) {
 388                 struct string_list_item *item;
 389                 struct rename *re;
 390                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 391                 if (pair->status != 'R') {
 392                         diff_free_filepair(pair);
 393                         continue;
 394                 }
 395                 re = xmalloc(sizeof(*re));
 396                 re->processed = 0;
 397                 re->pair = pair;
 398                 item = string_list_lookup(entries, re->pair->one->path);
 399                 if (!item)
 400                         re->src_entry = insert_stage_data(re->pair->one->path,
 401                                         o_tree, a_tree, b_tree, entries);
 402                 else
 403                         re->src_entry = item->util;
 404
 405                 item = string_list_lookup(entries, re->pair->two->path);
 406                 if (!item)
 407                         re->dst_entry = insert_stage_data(re->pair->two->path,
 408                                         o_tree, a_tree, b_tree, entries);
 409                 else
 410                         re->dst_entry = item->util;
 411                 item = string_list_insert(renames, pair->one->path);
 412                 item->util = re;
 413         }
 414         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 415         diff_queued_diff.nr = 0;
 416         diff_flush(&opts);
 417         return renames;
 418 }
 419
 420 static int update_stages(const char *path, struct diff_filespec *o,
 421                          struct diff_filespec *a, struct diff_filespec *b,
 422                          int clear)
 423 {
 424         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 425         if (clear)
 426                 if (remove_file_from_cache(path))
 427                         return -1;
 428         if (o)
 429                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 430                         return -1;
 431         if (a)
 432                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 433                         return -1;
 434         if (b)
 435                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 436                         return -1;
 437         return 0;
 438 }
 439
 440 static int remove_file(struct merge_options *o, int clean,
 441                        const char *path, int no_wd)
 442 {
 443         int update_cache = o->call_depth || clean;
 444         int update_working_directory = !o->call_depth && !no_wd;
 445
 446         if (update_cache) {
 447                 if (remove_file_from_cache(path))
 448                         return -1;
 449         }
 450         if (update_working_directory) {
 451                 if (remove_path(path))
 452                         return -1;
 453         }
 454         return 0;
 455 }
 456
 457 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 458 {
 459         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 460         int suffix = 0;
 461         struct stat st;
 462         char *p = newpath + strlen(path);
 463         strcpy(newpath, path);
 464         *(p++) = '~';
 465         strcpy(p, branch);
 466         for (; *p; ++p)
 467                 if ('/' == *p)
 468                         *p = '_';
 469         while (string_list_has_string(&o->current_file_set, newpath) ||
 470                string_list_has_string(&o->current_directory_set, newpath) ||
 471                lstat(newpath, &st) == 0)
 472                 sprintf(p, "_%d", suffix++);
 473
 474         string_list_insert(&o->current_file_set, newpath);
 475         return newpath;
 476 }
 477
 478 static void flush_buffer(int fd, const char *buf, unsigned long size)
 479 {
 480         while (size > 0) {
 481                 long ret = write_in_full(fd, buf, size);
 482                 if (ret < 0) {
 483                         /* Ignore epipe */
 484                         if (errno == EPIPE)
 485                                 break;
 486                         die_errno("merge-recursive");
 487                 } else if (!ret) {
 488                         die("merge-recursive: disk full?");
 489                 }
 490                 size -= ret;
 491                 buf += ret;
 492         }
 493 }
 494
 495 static int would_lose_untracked(const char *path)
 496 {
 497         int pos = cache_name_pos(path, strlen(path));
 498
 499         if (pos < 0)
 500                 pos = -1 - pos;
 501         while (pos < active_nr &&
 502                !strcmp(path, active_cache[pos]->name)) {
 503                 /*
 504                  * If stage #0, it is definitely tracked.
 505                  * If it has stage #2 then it was tracked
 506                  * before this merge started.  All other
 507                  * cases the path was not tracked.
 508                  */
 509                 switch (ce_stage(active_cache[pos])) {
 510                 case 0:
 511                 case 2:
 512                         return 0;
 513                 }
 514                 pos++;
 515         }
 516         return file_exists(path);
 517 }
 518
 519 static int make_room_for_path(const char *path)
 520 {
 521         int status;
 522         const char *msg = "failed to create path '%s'%s";
 523
 524         status = safe_create_leading_directories_const(path);
 525         if (status) {
 526                 if (status == -3) {
 527                         /* something else exists */
 528                         error(msg, path, ": perhaps a D/F conflict?");
 529                         return -1;
 530                 }
 531                 die(msg, path, "");
 532         }
 533
 534         /*
 535          * Do not unlink a file in the work tree if we are not
 536          * tracking it.
 537          */
 538         if (would_lose_untracked(path))
 539                 return error("refusing to lose untracked file at '%s'",
 540                              path);
 541
 542         /* Successful unlink is good.. */
 543         if (!unlink(path))
 544                 return 0;
 545         /* .. and so is no existing file */
 546         if (errno == ENOENT)
 547                 return 0;
 548         /* .. but not some other error (who really cares what?) */
 549         return error(msg, path, ": perhaps a D/F conflict?");
 550 }
 551
 552 static void update_file_flags(struct merge_options *o,
 553                               const unsigned char *sha,
 554                               unsigned mode,
 555                               const char *path,
 556                               int update_cache,
 557                               int update_wd)
 558 {
 559         if (o->call_depth)
 560                 update_wd = 0;
 561
 562         if (update_wd) {
 563                 enum object_type type;
 564                 void *buf;
 565                 unsigned long size;
 566
 567                 if (S_ISGITLINK(mode)) {
 568                         /*
 569                          * We may later decide to recursively descend into
 570                          * the submodule directory and update its index
 571                          * and/or work tree, but we do not do that now.
 572                          */
 573                         update_wd = 0;
 574                         goto update_index;
 575                 }
 576
 577                 buf = read_sha1_file(sha, &type, &size);
 578                 if (!buf)
 579                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 580                 if (type != OBJ_BLOB)
 581                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 582                 if (S_ISREG(mode)) {
 583                         struct strbuf strbuf = STRBUF_INIT;
 584                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 585                                 free(buf);
 586                                 size = strbuf.len;
 587                                 buf = strbuf_detach(&strbuf, NULL);
 588                         }
 589                 }
 590
 591                 if (make_room_for_path(path) < 0) {
 592                         update_wd = 0;
 593                         free(buf);
 594                         goto update_index;
 595                 }
 596                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 597                         int fd;
 598                         if (mode & 0100)
 599                                 mode = 0777;
 600                         else
 601                                 mode = 0666;
 602                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 603                         if (fd < 0)
 604                                 die_errno("failed to open '%s'", path);
 605                         flush_buffer(fd, buf, size);
 606                         close(fd);
 607                 } else if (S_ISLNK(mode)) {
 608                         char *lnk = xmemdupz(buf, size);
 609                         safe_create_leading_directories_const(path);
 610                         unlink(path);
 611                         if (symlink(lnk, path))
 612                                 die_errno("failed to symlink '%s'", path);
 613                         free(lnk);
 614                 } else
 615                         die("do not know what to do with %06o %s '%s'",
 616                             mode, sha1_to_hex(sha), path);
 617                 free(buf);
 618         }
 619  update_index:
 620         if (update_cache)
 621                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 622 }
 623
 624 static void update_file(struct merge_options *o,
 625                         int clean,
 626                         const unsigned char *sha,
 627                         unsigned mode,
 628                         const char *path)
 629 {
 630         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 631 }
 632
 633 /* Low level file merging, update and removal */
 634
 635 struct merge_file_info
 636 {
 637         unsigned char sha[20];
 638         unsigned mode;
 639         unsigned clean:1,
 640                  merge:1;
 641 };
 642
 643 static int merge_3way(struct merge_options *o,
 644                       mmbuffer_t *result_buf,
 645                       struct diff_filespec *one,
 646                       struct diff_filespec *a,
 647                       struct diff_filespec *b,
 648                       const char *branch1,
 649                       const char *branch2)
 650 {
 651         mmfile_t orig, src1, src2;
 652         char *base_name, *name1, *name2;
 653         int merge_status;
 654         int favor;
 655
 656         if (o->call_depth)
 657                 favor = 0;
 658         else {
 659                 switch (o->recursive_variant) {
 660                 case MERGE_RECURSIVE_OURS:
 661                         favor = XDL_MERGE_FAVOR_OURS;
 662                         break;
 663                 case MERGE_RECURSIVE_THEIRS:
 664                         favor = XDL_MERGE_FAVOR_THEIRS;
 665                         break;
 666                 default:
 667                         favor = 0;
 668                         break;
 669                 }
 670         }
 671
 672         if (strcmp(a->path, b->path) ||
 673             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 674                 base_name = o->ancestor == NULL ? NULL :
 675                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 676                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 677                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 678         } else {
 679                 base_name = o->ancestor == NULL ? NULL :
 680                         xstrdup(mkpath("%s", o->ancestor));
 681                 name1 = xstrdup(mkpath("%s", branch1));
 682                 name2 = xstrdup(mkpath("%s", branch2));
 683         }
 684
 685         read_mmblob(&orig, one->sha1);
 686         read_mmblob(&src1, a->sha1);
 687         read_mmblob(&src2, b->sha1);
 688
 689         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 690                                 &src1, name1, &src2, name2,
 691                                 ((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
 692                                  (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
 693                                  create_ll_flag(favor)));
 694
 695         free(name1);
 696         free(name2);
 697         free(orig.ptr);
 698         free(src1.ptr);
 699         free(src2.ptr);
 700         return merge_status;
 701 }
 702
 703 static struct merge_file_info merge_file(struct merge_options *o,
 704                                          struct diff_filespec *one,
 705                                          struct diff_filespec *a,
 706                                          struct diff_filespec *b,
 707                                          const char *branch1,
 708                                          const char *branch2)
 709 {
 710         struct merge_file_info result;
 711         result.merge = 0;
 712         result.clean = 1;
 713
 714         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 715                 result.clean = 0;
 716                 if (S_ISREG(a->mode)) {
 717                         result.mode = a->mode;
 718                         hashcpy(result.sha, a->sha1);
 719                 } else {
 720                         result.mode = b->mode;
 721                         hashcpy(result.sha, b->sha1);
 722                 }
 723         } else {
 724                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 725                         result.merge = 1;
 726
 727                 /*
 728                  * Merge modes
 729                  */
 730                 if (a->mode == b->mode || a->mode == one->mode)
 731                         result.mode = b->mode;
 732                 else {
 733                         result.mode = a->mode;
 734                         if (b->mode != one->mode) {
 735                                 result.clean = 0;
 736                                 result.merge = 1;
 737                         }
 738                 }
 739
 740                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 741                         hashcpy(result.sha, b->sha1);
 742                 else if (sha_eq(b->sha1, one->sha1))
 743                         hashcpy(result.sha, a->sha1);
 744                 else if (S_ISREG(a->mode)) {
 745                         mmbuffer_t result_buf;
 746                         int merge_status;
 747
 748                         merge_status = merge_3way(o, &result_buf, one, a, b,
 749                                                   branch1, branch2);
 750
 751                         if ((merge_status < 0) || !result_buf.ptr)
 752                                 die("Failed to execute internal merge");
 753
 754                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 755                                             blob_type, result.sha))
 756                                 die("Unable to add %s to database",
 757                                     a->path);
 758
 759                         free(result_buf.ptr);
 760                         result.clean = (merge_status == 0);
 761                 } else if (S_ISGITLINK(a->mode)) {
 762                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 763                                                        a->sha1, b->sha1);
 764                 } else if (S_ISLNK(a->mode)) {
 765                         hashcpy(result.sha, a->sha1);
 766
 767                         if (!sha_eq(a->sha1, b->sha1))
 768                                 result.clean = 0;
 769                 } else {
 770                         die("unsupported object type in the tree");
 771                 }
 772         }
 773
 774         return result;
 775 }
 776
 777 static void conflict_rename_delete(struct merge_options *o,
 778                                    struct diff_filepair *pair,
 779                                    const char *rename_branch,
 780                                    const char *other_branch)
 781 {
 782         char *dest_name = pair->two->path;
 783
 784         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 785                "and deleted in %s",
 786                pair->one->path, pair->two->path, rename_branch,
 787                other_branch);
 788         if (!o->call_depth)
 789                 update_stages(dest_name, NULL,
 790                               rename_branch == o->branch1 ? pair->two : NULL,
 791                               rename_branch == o->branch1 ? NULL : pair->two,
 792                               1);
 793         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 794 }
 795
 796 static void conflict_rename_rename_1to2(struct merge_options *o,
 797                                         struct rename *ren1,
 798                                         const char *branch1,
 799                                         struct rename *ren2,
 800                                         const char *branch2)
 801 {
 802         /* One file was renamed in both branches, but to different names. */
 803         char *del[2];
 804         int delp = 0;
 805         const char *ren1_dst = ren1->pair->two->path;
 806         const char *ren2_dst = ren2->pair->two->path;
 807         const char *dst_name1 = ren1_dst;
 808         const char *dst_name2 = ren2_dst;
 809         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 810                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 811                 output(o, 1, "%s is a directory in %s adding as %s instead",
 812                        ren1_dst, branch2, dst_name1);
 813                 remove_file(o, 0, ren1_dst, 0);
 814         }
 815         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 816                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 817                 output(o, 1, "%s is a directory in %s adding as %s instead",
 818                        ren2_dst, branch1, dst_name2);
 819                 remove_file(o, 0, ren2_dst, 0);
 820         }
 821         if (o->call_depth) {
 822                 remove_file_from_cache(dst_name1);
 823                 remove_file_from_cache(dst_name2);
 824                 /*
 825                  * Uncomment to leave the conflicting names in the resulting tree
 826                  *
 827                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 828                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 829                  */
 830         } else {
 831                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 832                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 833         }
 834         while (delp--)
 835                 free(del[delp]);
 836 }
 837
 838 static void conflict_rename_rename_2to1(struct merge_options *o,
 839                                         struct rename *ren1,
 840                                         const char *branch1,
 841                                         struct rename *ren2,
 842                                         const char *branch2)
 843 {
 844         /* Two files were renamed to the same thing. */
 845         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 846         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 847         output(o, 1, "Renaming %s to %s and %s to %s instead",
 848                ren1->pair->one->path, new_path1,
 849                ren2->pair->one->path, new_path2);
 850         remove_file(o, 0, ren1->pair->two->path, 0);
 851         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 852         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 853         free(new_path2);
 854         free(new_path1);
 855 }
 856
 857 static int process_renames(struct merge_options *o,
 858                            struct string_list *a_renames,
 859                            struct string_list *b_renames)
 860 {
 861         int clean_merge = 1, i, j;
 862         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 863         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 864         const struct rename *sre;
 865
 866         for (i = 0; i < a_renames->nr; i++) {
 867                 sre = a_renames->items[i].util;
 868                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 869                         = sre->dst_entry;
 870         }
 871         for (i = 0; i < b_renames->nr; i++) {
 872                 sre = b_renames->items[i].util;
 873                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 874                         = sre->dst_entry;
 875         }
 876
 877         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 878                 char *src;
 879                 struct string_list *renames1, *renames2Dst;
 880                 struct rename *ren1 = NULL, *ren2 = NULL;
 881                 const char *branch1, *branch2;
 882                 const char *ren1_src, *ren1_dst;
 883
 884                 if (i >= a_renames->nr) {
 885                         ren2 = b_renames->items[j++].util;
 886                 } else if (j >= b_renames->nr) {
 887                         ren1 = a_renames->items[i++].util;
 888                 } else {
 889                         int compare = strcmp(a_renames->items[i].string,
 890                                              b_renames->items[j].string);
 891                         if (compare <= 0)
 892                                 ren1 = a_renames->items[i++].util;
 893                         if (compare >= 0)
 894                                 ren2 = b_renames->items[j++].util;
 895                 }
 896
 897                 /* TODO: refactor, so that 1/2 are not needed */
 898                 if (ren1) {
 899                         renames1 = a_renames;
 900                         renames2Dst = &b_by_dst;
 901                         branch1 = o->branch1;
 902                         branch2 = o->branch2;
 903                 } else {
 904                         struct rename *tmp;
 905                         renames1 = b_renames;
 906                         renames2Dst = &a_by_dst;
 907                         branch1 = o->branch2;
 908                         branch2 = o->branch1;
 909                         tmp = ren2;
 910                         ren2 = ren1;
 911                         ren1 = tmp;
 912                 }
 913                 src = ren1->pair->one->path;
 914
 915                 ren1->dst_entry->processed = 1;
 916                 ren1->src_entry->processed = 1;
 917
 918                 if (ren1->processed)
 919                         continue;
 920                 ren1->processed = 1;
 921
 922                 ren1_src = ren1->pair->one->path;
 923                 ren1_dst = ren1->pair->two->path;
 924
 925                 if (ren2) {
 926                         const char *ren2_src = ren2->pair->one->path;
 927                         const char *ren2_dst = ren2->pair->two->path;
 928                         /* Renamed in 1 and renamed in 2 */
 929                         if (strcmp(ren1_src, ren2_src) != 0)
 930                                 die("ren1.src != ren2.src");
 931                         ren2->dst_entry->processed = 1;
 932                         ren2->processed = 1;
 933                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 934                                 clean_merge = 0;
 935                                 output(o, 1, "CONFLICT (rename/rename): "
 936                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 937                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 938                                        src, ren1_dst, branch1,
 939                                        src, ren2_dst, branch2,
 940                                        o->call_depth ? " (left unresolved)": "");
 941                                 if (o->call_depth) {
 942                                         remove_file_from_cache(src);
 943                                         update_file(o, 0, ren1->pair->one->sha1,
 944                                                     ren1->pair->one->mode, src);
 945                                 }
 946                                 conflict_rename_rename_1to2(o, ren1, branch1, ren2, branch2);
 947                         } else {
 948                                 struct merge_file_info mfi;
 949                                 remove_file(o, 1, ren1_src, 1);
 950                                 mfi = merge_file(o,
 951                                                  ren1->pair->one,
 952                                                  ren1->pair->two,
 953                                                  ren2->pair->two,
 954                                                  branch1,
 955                                                  branch2);
 956                                 if (mfi.merge || !mfi.clean)
 957                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 958
 959                                 if (mfi.merge)
 960                                         output(o, 2, "Auto-merging %s", ren1_dst);
 961
 962                                 if (!mfi.clean) {
 963                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 964                                                ren1_dst);
 965                                         clean_merge = 0;
 966
 967                                         if (!o->call_depth)
 968                                                 update_stages(ren1_dst,
 969                                                               ren1->pair->one,
 970                                                               ren1->pair->two,
 971                                                               ren2->pair->two,
 972                                                               1 /* clear */);
 973                                 }
 974                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 975                         }
 976                 } else {
 977                         /* Renamed in 1, maybe changed in 2 */
 978                         struct string_list_item *item;
 979                         /* we only use sha1 and mode of these */
 980                         struct diff_filespec src_other, dst_other;
 981                         int try_merge;
 982
 983                         /*
 984                          * unpack_trees loads entries from common-commit
 985                          * into stage 1, from head-commit into stage 2, and
 986                          * from merge-commit into stage 3.  We keep track
 987                          * of which side corresponds to the rename.
 988                          */
 989                         int renamed_stage = a_renames == renames1 ? 2 : 3;
 990                         int other_stage =   a_renames == renames1 ? 3 : 2;
 991
 992                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
 993
 994                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
 995                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
 996                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
 997                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
 998                         try_merge = 0;
 999
1000                         if (sha_eq(src_other.sha1, null_sha1)) {
1001                                 clean_merge = 0;
1002                                 conflict_rename_delete(o, ren1->pair, branch1, branch2);
1003                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1004                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1005                                 /* Added file on the other side
1006                                    identical to the file being
1007                                    renamed: clean merge */
1008                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1009                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1010                                 const char *new_path;
1011                                 clean_merge = 0;
1012                                 try_merge = 1;
1013                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1014                                        "%s added in %s",
1015                                        ren1_src, ren1_dst, branch1,
1016                                        ren1_dst, branch2);
1017                                 if (o->call_depth) {
1018                                         struct merge_file_info mfi;
1019                                         struct diff_filespec one, a, b;
1020
1021                                         one.path = a.path = b.path =
1022                                                 (char *)ren1_dst;
1023                                         hashcpy(one.sha1, null_sha1);
1024                                         one.mode = 0;
1025                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1026                                         a.mode = ren1->pair->two->mode;
1027                                         hashcpy(b.sha1, dst_other.sha1);
1028                                         b.mode = dst_other.mode;
1029                                         mfi = merge_file(o, &one, &a, &b,
1030                                                          branch1,
1031                                                          branch2);
1032                                         output(o, 1, "Adding merged %s", ren1_dst);
1033                                         update_file(o, 0,
1034                                                     mfi.sha,
1035                                                     mfi.mode,
1036                                                     ren1_dst);
1037                                 } else {
1038                                         new_path = unique_path(o, ren1_dst, branch2);
1039                                         output(o, 1, "Adding as %s instead", new_path);
1040                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1041                                 }
1042                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1043                                 ren2 = item->util;
1044                                 clean_merge = 0;
1045                                 ren2->processed = 1;
1046                                 output(o, 1, "CONFLICT (rename/rename): "
1047                                        "Rename %s->%s in %s. "
1048                                        "Rename %s->%s in %s",
1049                                        ren1_src, ren1_dst, branch1,
1050                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1051                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1052                         } else
1053                                 try_merge = 1;
1054
1055                         if (try_merge) {
1056                                 struct diff_filespec *one, *a, *b;
1057                                 struct merge_file_info mfi;
1058                                 src_other.path = (char *)ren1_src;
1059
1060                                 one = ren1->pair->one;
1061                                 if (a_renames == renames1) {
1062                                         a = ren1->pair->two;
1063                                         b = &src_other;
1064                                 } else {
1065                                         b = ren1->pair->two;
1066                                         a = &src_other;
1067                                 }
1068                                 mfi = merge_file(o, one, a, b,
1069                                                 o->branch1, o->branch2);
1070
1071                                 if (mfi.clean &&
1072                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1073                                     mfi.mode == ren1->pair->two->mode) {
1074                                         /*
1075                                          * This message is part of
1076                                          * t6022 test. If you change
1077                                          * it update the test too.
1078                                          */
1079                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1080
1081                                         /* There may be higher stage entries left
1082                                          * in the index (e.g. due to a D/F
1083                                          * conflict) that need to be resolved.
1084                                          */
1085                                         if (!ren1->dst_entry->stages[2].mode !=
1086                                             !ren1->dst_entry->stages[3].mode)
1087                                                 ren1->dst_entry->processed = 0;
1088                                 } else {
1089                                         if (mfi.merge || !mfi.clean)
1090                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1091                                         if (mfi.merge)
1092                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1093                                         if (!mfi.clean) {
1094                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1095                                                        ren1_dst);
1096                                                 clean_merge = 0;
1097
1098                                                 if (!o->call_depth)
1099                                                         update_stages(ren1_dst,
1100                                                                       one, a, b, 1);
1101                                         }
1102                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1103                                 }
1104                         }
1105                 }
1106         }
1107         string_list_clear(&a_by_dst, 0);
1108         string_list_clear(&b_by_dst, 0);
1109
1110         return clean_merge;
1111 }
1112
1113 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1114 {
1115         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1116 }
1117
1118 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1119 {
1120         void *buf;
1121         enum object_type type;
1122         unsigned long size;
1123         buf = read_sha1_file(sha1, &type, &size);
1124         if (!buf)
1125                 return error("cannot read object %s", sha1_to_hex(sha1));
1126         if (type != OBJ_BLOB) {
1127                 free(buf);
1128                 return error("object %s is not a blob", sha1_to_hex(sha1));
1129         }
1130         strbuf_attach(dst, buf, size, size + 1);
1131         return 0;
1132 }
1133
1134 static int blob_unchanged(const unsigned char *o_sha,
1135                           const unsigned char *a_sha,
1136                           int renormalize, const char *path)
1137 {
1138         struct strbuf o = STRBUF_INIT;
1139         struct strbuf a = STRBUF_INIT;
1140         int ret = 0; /* assume changed for safety */
1141
1142         if (sha_eq(o_sha, a_sha))
1143                 return 1;
1144         if (!renormalize)
1145                 return 0;
1146
1147         assert(o_sha && a_sha);
1148         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1149                 goto error_return;
1150         /*
1151          * Note: binary | is used so that both renormalizations are
1152          * performed.  Comparison can be skipped if both files are
1153          * unchanged since their sha1s have already been compared.
1154          */
1155         if (renormalize_buffer(path, o.buf, o.len, &o) |
1156             renormalize_buffer(path, a.buf, o.len, &a))
1157                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1158
1159 error_return:
1160         strbuf_release(&o);
1161         strbuf_release(&a);
1162         return ret;
1163 }
1164
1165 static void handle_delete_modify(struct merge_options *o,
1166                                  const char *path,
1167                                  unsigned char *a_sha, int a_mode,
1168                                  unsigned char *b_sha, int b_mode)
1169 {
1170         if (!a_sha) {
1171                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1172                        "and modified in %s. Version %s of %s left in tree.",
1173                        path, o->branch1,
1174                        o->branch2, o->branch2, path);
1175                 update_file(o, 0, b_sha, b_mode, path);
1176         } else {
1177                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1178                        "and modified in %s. Version %s of %s left in tree.",
1179                        path, o->branch2,
1180                        o->branch1, o->branch1, path);
1181                 update_file(o, 0, a_sha, a_mode, path);
1182         }
1183 }
1184
1185
1186 static int merge_content(struct merge_options *o,
1187                          const char *path,
1188                          unsigned char *o_sha, int o_mode,
1189                          unsigned char *a_sha, int a_mode,
1190                          unsigned char *b_sha, int b_mode)
1191 {
1192         const char *reason = "content";
1193         struct merge_file_info mfi;
1194         struct diff_filespec one, a, b;
1195
1196         if (!o_sha) {
1197                 reason = "add/add";
1198                 o_sha = (unsigned char *)null_sha1;
1199         }
1200         one.path = a.path = b.path = (char *)path;
1201         hashcpy(one.sha1, o_sha);
1202         one.mode = o_mode;
1203         hashcpy(a.sha1, a_sha);
1204         a.mode = a_mode;
1205         hashcpy(b.sha1, b_sha);
1206         b.mode = b_mode;
1207
1208         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1209         if (mfi.clean && sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1210                 output(o, 3, "Skipped %s (merged same as existing)", path);
1211         else
1212                 output(o, 2, "Auto-merging %s", path);
1213
1214         if (!mfi.clean) {
1215                 if (S_ISGITLINK(mfi.mode))
1216                         reason = "submodule";
1217                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1218                                 reason, path);
1219         }
1220
1221         update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1222         return mfi.clean;
1223
1224 }
1225
1226 /* Per entry merge function */
1227 static int process_entry(struct merge_options *o,
1228                          const char *path, struct stage_data *entry)
1229 {
1230         /*
1231         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1232         print_index_entry("\tpath: ", entry);
1233         */
1234         int clean_merge = 1;
1235         int normalize = o->renormalize;
1236         unsigned o_mode = entry->stages[1].mode;
1237         unsigned a_mode = entry->stages[2].mode;
1238         unsigned b_mode = entry->stages[3].mode;
1239         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1240         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1241         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1242
1243         entry->processed = 1;
1244         if (o_sha && (!a_sha || !b_sha)) {
1245                 /* Case A: Deleted in one */
1246                 if ((!a_sha && !b_sha) ||
1247                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1248                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1249                         /* Deleted in both or deleted in one and
1250                          * unchanged in the other */
1251                         if (a_sha)
1252                                 output(o, 2, "Removing %s", path);
1253                         /* do not touch working file if it did not exist */
1254                         remove_file(o, 1, path, !a_sha);
1255                 } else {
1256                         /* Deleted in one and changed in the other */
1257                         clean_merge = 0;
1258                         handle_delete_modify(o, path,
1259                                              a_sha, a_mode, b_sha, b_mode);
1260                 }
1261
1262         } else if ((!o_sha && a_sha && !b_sha) ||
1263                    (!o_sha && !a_sha && b_sha)) {
1264                 /* Case B: Added in one. */
1265                 unsigned mode;
1266                 const unsigned char *sha;
1267
1268                 if (a_sha) {
1269                         mode = a_mode;
1270                         sha = a_sha;
1271                 } else {
1272                         mode = b_mode;
1273                         sha = b_sha;
1274                 }
1275                 if (string_list_has_string(&o->current_directory_set, path)) {
1276                         /* Handle D->F conflicts after all subfiles */
1277                         entry->processed = 0;
1278                         /* But get any file out of the way now, so conflicted
1279                          * entries below the directory of the same name can
1280                          * be put in the working directory.
1281                          */
1282                         if (a_sha)
1283                                 output(o, 2, "Removing %s", path);
1284                         /* do not touch working file if it did not exist */
1285                         remove_file(o, 0, path, !a_sha);
1286                         return 1; /* Assume clean till processed */
1287                 } else {
1288                         output(o, 2, "Adding %s", path);
1289                         update_file(o, 1, sha, mode, path);
1290                 }
1291         } else if (a_sha && b_sha) {
1292                 /* Case C: Added in both (check for same permissions) and */
1293                 /* case D: Modified in both, but differently. */
1294                 clean_merge = merge_content(o, path,
1295                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode);
1296         } else if (!o_sha && !a_sha && !b_sha) {
1297                 /*
1298                  * this entry was deleted altogether. a_mode == 0 means
1299                  * we had that path and want to actively remove it.
1300                  */
1301                 remove_file(o, 1, path, !a_mode);
1302         } else
1303                 die("Fatal merge failure, shouldn't happen.");
1304
1305         return clean_merge;
1306 }
1307
1308 /*
1309  * Per entry merge function for D/F conflicts, to be called only after
1310  * all files below dir have been processed.  We do this because in the
1311  * cases we can cleanly resolve D/F conflicts, process_entry() can clean
1312  * out all the files below the directory for us.
1313  */
1314 static int process_df_entry(struct merge_options *o,
1315                          const char *path, struct stage_data *entry)
1316 {
1317         int clean_merge = 1;
1318         unsigned o_mode = entry->stages[1].mode;
1319         unsigned a_mode = entry->stages[2].mode;
1320         unsigned b_mode = entry->stages[3].mode;
1321         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1322         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1323         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1324         const char *add_branch;
1325         const char *other_branch;
1326         unsigned mode;
1327         const unsigned char *sha;
1328         const char *conf;
1329         struct stat st;
1330
1331         if (!((!o_sha && a_sha && !b_sha) || (!o_sha && !a_sha && b_sha)))
1332                 return 1; /* we don't handle non D-F cases */
1333
1334         entry->processed = 1;
1335
1336         if (a_sha) {
1337                 add_branch = o->branch1;
1338                 other_branch = o->branch2;
1339                 mode = a_mode;
1340                 sha = a_sha;
1341                 conf = "file/directory";
1342         } else {
1343                 add_branch = o->branch2;
1344                 other_branch = o->branch1;
1345                 mode = b_mode;
1346                 sha = b_sha;
1347                 conf = "directory/file";
1348         }
1349         if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1350                 const char *new_path = unique_path(o, path, add_branch);
1351                 clean_merge = 0;
1352                 output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1353                        "Adding %s as %s",
1354                        conf, path, other_branch, path, new_path);
1355                 remove_file(o, 0, path, 0);
1356                 update_file(o, 0, sha, mode, new_path);
1357         } else {
1358                 output(o, 2, "Adding %s", path);
1359                 update_file(o, 1, sha, mode, path);
1360         }
1361
1362         return clean_merge;
1363 }
1364
1365 int merge_trees(struct merge_options *o,
1366                 struct tree *head,
1367                 struct tree *merge,
1368                 struct tree *common,
1369                 struct tree **result)
1370 {
1371         int code, clean;
1372
1373         if (o->subtree_shift) {
1374                 merge = shift_tree_object(head, merge, o->subtree_shift);
1375                 common = shift_tree_object(head, common, o->subtree_shift);
1376         }
1377
1378         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1379                 output(o, 0, "Already up-to-date!");
1380                 *result = head;
1381                 return 1;
1382         }
1383
1384         code = git_merge_trees(o->call_depth, common, head, merge);
1385
1386         if (code != 0) {
1387                 if (show(o, 4) || o->call_depth)
1388                         die("merging of trees %s and %s failed",
1389                             sha1_to_hex(head->object.sha1),
1390                             sha1_to_hex(merge->object.sha1));
1391                 else
1392                         exit(128);
1393         }
1394
1395         if (unmerged_cache()) {
1396                 struct string_list *entries, *re_head, *re_merge;
1397                 int i;
1398                 string_list_clear(&o->current_file_set, 1);
1399                 string_list_clear(&o->current_directory_set, 1);
1400                 get_files_dirs(o, head);
1401                 get_files_dirs(o, merge);
1402
1403                 entries = get_unmerged();
1404                 re_head  = get_renames(o, head, common, head, merge, entries);
1405                 re_merge = get_renames(o, merge, common, head, merge, entries);
1406                 clean = process_renames(o, re_head, re_merge);
1407                 for (i = 0; i < entries->nr; i++) {
1408                         const char *path = entries->items[i].string;
1409                         struct stage_data *e = entries->items[i].util;
1410                         if (!e->processed
1411                                 && !process_entry(o, path, e))
1412                                 clean = 0;
1413                 }
1414                 for (i = 0; i < entries->nr; i++) {
1415                         const char *path = entries->items[i].string;
1416                         struct stage_data *e = entries->items[i].util;
1417                         if (!e->processed
1418                                 && !process_df_entry(o, path, e))
1419                                 clean = 0;
1420                 }
1421                 for (i = 0; i < entries->nr; i++) {
1422                         struct stage_data *e = entries->items[i].util;
1423                         if (!e->processed)
1424                                 die("Unprocessed path??? %s",
1425                                     entries->items[i].string);
1426                 }
1427
1428                 string_list_clear(re_merge, 0);
1429                 string_list_clear(re_head, 0);
1430                 string_list_clear(entries, 1);
1431
1432         }
1433         else
1434                 clean = 1;
1435
1436         if (o->call_depth)
1437                 *result = write_tree_from_memory(o);
1438
1439         return clean;
1440 }
1441
1442 static struct commit_list *reverse_commit_list(struct commit_list *list)
1443 {
1444         struct commit_list *next = NULL, *current, *backup;
1445         for (current = list; current; current = backup) {
1446                 backup = current->next;
1447                 current->next = next;
1448                 next = current;
1449         }
1450         return next;
1451 }
1452
1453 /*
1454  * Merge the commits h1 and h2, return the resulting virtual
1455  * commit object and a flag indicating the cleanness of the merge.
1456  */
1457 int merge_recursive(struct merge_options *o,
1458                     struct commit *h1,
1459                     struct commit *h2,
1460                     struct commit_list *ca,
1461                     struct commit **result)
1462 {
1463         struct commit_list *iter;
1464         struct commit *merged_common_ancestors;
1465         struct tree *mrtree = mrtree;
1466         int clean;
1467
1468         if (show(o, 4)) {
1469                 output(o, 4, "Merging:");
1470                 output_commit_title(o, h1);
1471                 output_commit_title(o, h2);
1472         }
1473
1474         if (!ca) {
1475                 ca = get_merge_bases(h1, h2, 1);
1476                 ca = reverse_commit_list(ca);
1477         }
1478
1479         if (show(o, 5)) {
1480                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1481                 for (iter = ca; iter; iter = iter->next)
1482                         output_commit_title(o, iter->item);
1483         }
1484
1485         merged_common_ancestors = pop_commit(&ca);
1486         if (merged_common_ancestors == NULL) {
1487                 /* if there is no common ancestor, make an empty tree */
1488                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1489
1490                 tree->object.parsed = 1;
1491                 tree->object.type = OBJ_TREE;
1492                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1493                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1494         }
1495
1496         for (iter = ca; iter; iter = iter->next) {
1497                 const char *saved_b1, *saved_b2;
1498                 o->call_depth++;
1499                 /*
1500                  * When the merge fails, the result contains files
1501                  * with conflict markers. The cleanness flag is
1502                  * ignored, it was never actually used, as result of
1503                  * merge_trees has always overwritten it: the committed
1504                  * "conflicts" were already resolved.
1505                  */
1506                 discard_cache();
1507                 saved_b1 = o->branch1;
1508                 saved_b2 = o->branch2;
1509                 o->branch1 = "Temporary merge branch 1";
1510                 o->branch2 = "Temporary merge branch 2";
1511                 merge_recursive(o, merged_common_ancestors, iter->item,
1512                                 NULL, &merged_common_ancestors);
1513                 o->branch1 = saved_b1;
1514                 o->branch2 = saved_b2;
1515                 o->call_depth--;
1516
1517                 if (!merged_common_ancestors)
1518                         die("merge returned no commit");
1519         }
1520
1521         discard_cache();
1522         if (!o->call_depth)
1523                 read_cache();
1524
1525         o->ancestor = "merged common ancestors";
1526         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1527                             &mrtree);
1528
1529         if (o->call_depth) {
1530                 *result = make_virtual_commit(mrtree, "merged tree");
1531                 commit_list_insert(h1, &(*result)->parents);
1532                 commit_list_insert(h2, &(*result)->parents->next);
1533         }
1534         flush_output(o);
1535         return clean;
1536 }
1537
1538 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1539 {
1540         struct object *object;
1541
1542         object = deref_tag(parse_object(sha1), name, strlen(name));
1543         if (!object)
1544                 return NULL;
1545         if (object->type == OBJ_TREE)
1546                 return make_virtual_commit((struct tree*)object, name);
1547         if (object->type != OBJ_COMMIT)
1548                 return NULL;
1549         if (parse_commit((struct commit *)object))
1550                 return NULL;
1551         return (struct commit *)object;
1552 }
1553
1554 int merge_recursive_generic(struct merge_options *o,
1555                             const unsigned char *head,
1556                             const unsigned char *merge,
1557                             int num_base_list,
1558                             const unsigned char **base_list,
1559                             struct commit **result)
1560 {
1561         int clean, index_fd;
1562         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1563         struct commit *head_commit = get_ref(head, o->branch1);
1564         struct commit *next_commit = get_ref(merge, o->branch2);
1565         struct commit_list *ca = NULL;
1566
1567         if (base_list) {
1568                 int i;
1569                 for (i = 0; i < num_base_list; ++i) {
1570                         struct commit *base;
1571                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1572                                 return error("Could not parse object '%s'",
1573                                         sha1_to_hex(base_list[i]));
1574                         commit_list_insert(base, &ca);
1575                 }
1576         }
1577
1578         index_fd = hold_locked_index(lock, 1);
1579         clean = merge_recursive(o, head_commit, next_commit, ca,
1580                         result);
1581         if (active_cache_changed &&
1582                         (write_cache(index_fd, active_cache, active_nr) ||
1583                          commit_locked_index(lock)))
1584                 return error("Unable to write index.");
1585
1586         return clean ? 0 : 1;
1587 }
1588
1589 static int merge_recursive_config(const char *var, const char *value, void *cb)
1590 {
1591         struct merge_options *o = cb;
1592         if (!strcasecmp(var, "merge.verbosity")) {
1593                 o->verbosity = git_config_int(var, value);
1594                 return 0;
1595         }
1596         if (!strcasecmp(var, "diff.renamelimit")) {
1597                 o->diff_rename_limit = git_config_int(var, value);
1598                 return 0;
1599         }
1600         if (!strcasecmp(var, "merge.renamelimit")) {
1601                 o->merge_rename_limit = git_config_int(var, value);
1602                 return 0;
1603         }
1604         return git_xmerge_config(var, value, cb);
1605 }
1606
1607 void init_merge_options(struct merge_options *o)
1608 {
1609         memset(o, 0, sizeof(struct merge_options));
1610         o->verbosity = 2;
1611         o->buffer_output = 1;
1612         o->diff_rename_limit = -1;
1613         o->merge_rename_limit = -1;
1614         o->renormalize = 0;
1615         git_config(merge_recursive_config, o);
1616         if (getenv("GIT_MERGE_VERBOSITY"))
1617                 o->verbosity =
1618                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1619         if (o->verbosity >= 5)
1620                 o->buffer_output = 0;
1621         strbuf_init(&o->obuf, 0);
1622         memset(&o->current_file_set, 0, sizeof(struct string_list));
1623         o->current_file_set.strdup_strings = 1;
1624         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1625         o->current_directory_set.strdup_strings = 1;
1626 }