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_options(const char *path, struct diff_filespec *o,
 421                          struct diff_filespec *a, struct diff_filespec *b,
 422                          int clear, int options)
 423 {
 424         if (clear)
 425                 if (remove_file_from_cache(path))
 426                         return -1;
 427         if (o)
 428                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 429                         return -1;
 430         if (a)
 431                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 432                         return -1;
 433         if (b)
 434                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 435                         return -1;
 436         return 0;
 437 }
 438
 439 static int update_stages(const char *path, struct diff_filespec *o,
 440                          struct diff_filespec *a, struct diff_filespec *b,
 441                          int clear)
 442 {
 443         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 444         return update_stages_options(path, o, a, b, clear, options);
 445 }
 446
 447 static int update_stages_and_entry(const char *path,
 448                                    struct stage_data *entry,
 449                                    struct diff_filespec *o,
 450                                    struct diff_filespec *a,
 451                                    struct diff_filespec *b,
 452                                    int clear)
 453 {
 454         int options;
 455
 456         entry->processed = 0;
 457         entry->stages[1].mode = o->mode;
 458         entry->stages[2].mode = a->mode;
 459         entry->stages[3].mode = b->mode;
 460         hashcpy(entry->stages[1].sha, o->sha1);
 461         hashcpy(entry->stages[2].sha, a->sha1);
 462         hashcpy(entry->stages[3].sha, b->sha1);
 463         options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 464         return update_stages_options(path, o, a, b, clear, options);
 465 }
 466
 467 static int remove_file(struct merge_options *o, int clean,
 468                        const char *path, int no_wd)
 469 {
 470         int update_cache = o->call_depth || clean;
 471         int update_working_directory = !o->call_depth && !no_wd;
 472
 473         if (update_cache) {
 474                 if (remove_file_from_cache(path))
 475                         return -1;
 476         }
 477         if (update_working_directory) {
 478                 if (remove_path(path))
 479                         return -1;
 480         }
 481         return 0;
 482 }
 483
 484 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 485 {
 486         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 487         int suffix = 0;
 488         struct stat st;
 489         char *p = newpath + strlen(path);
 490         strcpy(newpath, path);
 491         *(p++) = '~';
 492         strcpy(p, branch);
 493         for (; *p; ++p)
 494                 if ('/' == *p)
 495                         *p = '_';
 496         while (string_list_has_string(&o->current_file_set, newpath) ||
 497                string_list_has_string(&o->current_directory_set, newpath) ||
 498                lstat(newpath, &st) == 0)
 499                 sprintf(p, "_%d", suffix++);
 500
 501         string_list_insert(&o->current_file_set, newpath);
 502         return newpath;
 503 }
 504
 505 static void flush_buffer(int fd, const char *buf, unsigned long size)
 506 {
 507         while (size > 0) {
 508                 long ret = write_in_full(fd, buf, size);
 509                 if (ret < 0) {
 510                         /* Ignore epipe */
 511                         if (errno == EPIPE)
 512                                 break;
 513                         die_errno("merge-recursive");
 514                 } else if (!ret) {
 515                         die("merge-recursive: disk full?");
 516                 }
 517                 size -= ret;
 518                 buf += ret;
 519         }
 520 }
 521
 522 static int would_lose_untracked(const char *path)
 523 {
 524         int pos = cache_name_pos(path, strlen(path));
 525
 526         if (pos < 0)
 527                 pos = -1 - pos;
 528         while (pos < active_nr &&
 529                !strcmp(path, active_cache[pos]->name)) {
 530                 /*
 531                  * If stage #0, it is definitely tracked.
 532                  * If it has stage #2 then it was tracked
 533                  * before this merge started.  All other
 534                  * cases the path was not tracked.
 535                  */
 536                 switch (ce_stage(active_cache[pos])) {
 537                 case 0:
 538                 case 2:
 539                         return 0;
 540                 }
 541                 pos++;
 542         }
 543         return file_exists(path);
 544 }
 545
 546 static int make_room_for_path(const char *path)
 547 {
 548         int status;
 549         const char *msg = "failed to create path '%s'%s";
 550
 551         status = safe_create_leading_directories_const(path);
 552         if (status) {
 553                 if (status == -3) {
 554                         /* something else exists */
 555                         error(msg, path, ": perhaps a D/F conflict?");
 556                         return -1;
 557                 }
 558                 die(msg, path, "");
 559         }
 560
 561         /*
 562          * Do not unlink a file in the work tree if we are not
 563          * tracking it.
 564          */
 565         if (would_lose_untracked(path))
 566                 return error("refusing to lose untracked file at '%s'",
 567                              path);
 568
 569         /* Successful unlink is good.. */
 570         if (!unlink(path))
 571                 return 0;
 572         /* .. and so is no existing file */
 573         if (errno == ENOENT)
 574                 return 0;
 575         /* .. but not some other error (who really cares what?) */
 576         return error(msg, path, ": perhaps a D/F conflict?");
 577 }
 578
 579 static void update_file_flags(struct merge_options *o,
 580                               const unsigned char *sha,
 581                               unsigned mode,
 582                               const char *path,
 583                               int update_cache,
 584                               int update_wd)
 585 {
 586         if (o->call_depth)
 587                 update_wd = 0;
 588
 589         if (update_wd) {
 590                 enum object_type type;
 591                 void *buf;
 592                 unsigned long size;
 593
 594                 if (S_ISGITLINK(mode)) {
 595                         /*
 596                          * We may later decide to recursively descend into
 597                          * the submodule directory and update its index
 598                          * and/or work tree, but we do not do that now.
 599                          */
 600                         update_wd = 0;
 601                         goto update_index;
 602                 }
 603
 604                 buf = read_sha1_file(sha, &type, &size);
 605                 if (!buf)
 606                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 607                 if (type != OBJ_BLOB)
 608                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 609                 if (S_ISREG(mode)) {
 610                         struct strbuf strbuf = STRBUF_INIT;
 611                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 612                                 free(buf);
 613                                 size = strbuf.len;
 614                                 buf = strbuf_detach(&strbuf, NULL);
 615                         }
 616                 }
 617
 618                 if (make_room_for_path(path) < 0) {
 619                         update_wd = 0;
 620                         free(buf);
 621                         goto update_index;
 622                 }
 623                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 624                         int fd;
 625                         if (mode & 0100)
 626                                 mode = 0777;
 627                         else
 628                                 mode = 0666;
 629                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 630                         if (fd < 0)
 631                                 die_errno("failed to open '%s'", path);
 632                         flush_buffer(fd, buf, size);
 633                         close(fd);
 634                 } else if (S_ISLNK(mode)) {
 635                         char *lnk = xmemdupz(buf, size);
 636                         safe_create_leading_directories_const(path);
 637                         unlink(path);
 638                         if (symlink(lnk, path))
 639                                 die_errno("failed to symlink '%s'", path);
 640                         free(lnk);
 641                 } else
 642                         die("do not know what to do with %06o %s '%s'",
 643                             mode, sha1_to_hex(sha), path);
 644                 free(buf);
 645         }
 646  update_index:
 647         if (update_cache)
 648                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 649 }
 650
 651 static void update_file(struct merge_options *o,
 652                         int clean,
 653                         const unsigned char *sha,
 654                         unsigned mode,
 655                         const char *path)
 656 {
 657         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 658 }
 659
 660 /* Low level file merging, update and removal */
 661
 662 struct merge_file_info
 663 {
 664         unsigned char sha[20];
 665         unsigned mode;
 666         unsigned clean:1,
 667                  merge:1;
 668 };
 669
 670 static int merge_3way(struct merge_options *o,
 671                       mmbuffer_t *result_buf,
 672                       struct diff_filespec *one,
 673                       struct diff_filespec *a,
 674                       struct diff_filespec *b,
 675                       const char *branch1,
 676                       const char *branch2)
 677 {
 678         mmfile_t orig, src1, src2;
 679         char *base_name, *name1, *name2;
 680         int merge_status;
 681         int favor;
 682
 683         if (o->call_depth)
 684                 favor = 0;
 685         else {
 686                 switch (o->recursive_variant) {
 687                 case MERGE_RECURSIVE_OURS:
 688                         favor = XDL_MERGE_FAVOR_OURS;
 689                         break;
 690                 case MERGE_RECURSIVE_THEIRS:
 691                         favor = XDL_MERGE_FAVOR_THEIRS;
 692                         break;
 693                 default:
 694                         favor = 0;
 695                         break;
 696                 }
 697         }
 698
 699         if (strcmp(a->path, b->path) ||
 700             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 701                 base_name = o->ancestor == NULL ? NULL :
 702                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 703                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 704                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 705         } else {
 706                 base_name = o->ancestor == NULL ? NULL :
 707                         xstrdup(mkpath("%s", o->ancestor));
 708                 name1 = xstrdup(mkpath("%s", branch1));
 709                 name2 = xstrdup(mkpath("%s", branch2));
 710         }
 711
 712         read_mmblob(&orig, one->sha1);
 713         read_mmblob(&src1, a->sha1);
 714         read_mmblob(&src2, b->sha1);
 715
 716         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 717                                 &src1, name1, &src2, name2,
 718                                 ((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
 719                                  (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
 720                                  create_ll_flag(favor)));
 721
 722         free(name1);
 723         free(name2);
 724         free(orig.ptr);
 725         free(src1.ptr);
 726         free(src2.ptr);
 727         return merge_status;
 728 }
 729
 730 static struct merge_file_info merge_file(struct merge_options *o,
 731                                          struct diff_filespec *one,
 732                                          struct diff_filespec *a,
 733                                          struct diff_filespec *b,
 734                                          const char *branch1,
 735                                          const char *branch2)
 736 {
 737         struct merge_file_info result;
 738         result.merge = 0;
 739         result.clean = 1;
 740
 741         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 742                 result.clean = 0;
 743                 if (S_ISREG(a->mode)) {
 744                         result.mode = a->mode;
 745                         hashcpy(result.sha, a->sha1);
 746                 } else {
 747                         result.mode = b->mode;
 748                         hashcpy(result.sha, b->sha1);
 749                 }
 750         } else {
 751                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 752                         result.merge = 1;
 753
 754                 /*
 755                  * Merge modes
 756                  */
 757                 if (a->mode == b->mode || a->mode == one->mode)
 758                         result.mode = b->mode;
 759                 else {
 760                         result.mode = a->mode;
 761                         if (b->mode != one->mode) {
 762                                 result.clean = 0;
 763                                 result.merge = 1;
 764                         }
 765                 }
 766
 767                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 768                         hashcpy(result.sha, b->sha1);
 769                 else if (sha_eq(b->sha1, one->sha1))
 770                         hashcpy(result.sha, a->sha1);
 771                 else if (S_ISREG(a->mode)) {
 772                         mmbuffer_t result_buf;
 773                         int merge_status;
 774
 775                         merge_status = merge_3way(o, &result_buf, one, a, b,
 776                                                   branch1, branch2);
 777
 778                         if ((merge_status < 0) || !result_buf.ptr)
 779                                 die("Failed to execute internal merge");
 780
 781                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 782                                             blob_type, result.sha))
 783                                 die("Unable to add %s to database",
 784                                     a->path);
 785
 786                         free(result_buf.ptr);
 787                         result.clean = (merge_status == 0);
 788                 } else if (S_ISGITLINK(a->mode)) {
 789                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 790                                                        a->sha1, b->sha1);
 791                 } else if (S_ISLNK(a->mode)) {
 792                         hashcpy(result.sha, a->sha1);
 793
 794                         if (!sha_eq(a->sha1, b->sha1))
 795                                 result.clean = 0;
 796                 } else {
 797                         die("unsupported object type in the tree");
 798                 }
 799         }
 800
 801         return result;
 802 }
 803
 804 static void conflict_rename_delete(struct merge_options *o,
 805                                    struct diff_filepair *pair,
 806                                    const char *rename_branch,
 807                                    const char *other_branch)
 808 {
 809         char *dest_name = pair->two->path;
 810         int df_conflict = 0;
 811         struct stat st;
 812
 813         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 814                "and deleted in %s",
 815                pair->one->path, pair->two->path, rename_branch,
 816                other_branch);
 817         if (!o->call_depth)
 818                 update_stages(dest_name, NULL,
 819                               rename_branch == o->branch1 ? pair->two : NULL,
 820                               rename_branch == o->branch1 ? NULL : pair->two,
 821                               1);
 822         if (lstat(dest_name, &st) == 0 && S_ISDIR(st.st_mode)) {
 823                 dest_name = unique_path(o, dest_name, rename_branch);
 824                 df_conflict = 1;
 825         }
 826         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 827         if (df_conflict)
 828                 free(dest_name);
 829 }
 830
 831 static void conflict_rename_rename_1to2(struct merge_options *o,
 832                                         struct diff_filepair *pair1,
 833                                         const char *branch1,
 834                                         struct diff_filepair *pair2,
 835                                         const char *branch2)
 836 {
 837         /* One file was renamed in both branches, but to different names. */
 838         char *del[2];
 839         int delp = 0;
 840         const char *ren1_dst = pair1->two->path;
 841         const char *ren2_dst = pair2->two->path;
 842         const char *dst_name1 = ren1_dst;
 843         const char *dst_name2 = ren2_dst;
 844         struct stat st;
 845         if (lstat(ren1_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 846                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 847                 output(o, 1, "%s is a directory in %s adding as %s instead",
 848                        ren1_dst, branch2, dst_name1);
 849         }
 850         if (lstat(ren2_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 851                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 852                 output(o, 1, "%s is a directory in %s adding as %s instead",
 853                        ren2_dst, branch1, dst_name2);
 854         }
 855         if (o->call_depth) {
 856                 remove_file_from_cache(dst_name1);
 857                 remove_file_from_cache(dst_name2);
 858                 /*
 859                  * Uncomment to leave the conflicting names in the resulting tree
 860                  *
 861                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 862                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 863                  */
 864         } else {
 865                 update_stages(ren1_dst, NULL, pair1->two, NULL, 1);
 866                 update_stages(ren2_dst, NULL, NULL, pair2->two, 1);
 867
 868                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 869                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 870         }
 871         while (delp--)
 872                 free(del[delp]);
 873 }
 874
 875 static void conflict_rename_rename_2to1(struct merge_options *o,
 876                                         struct rename *ren1,
 877                                         const char *branch1,
 878                                         struct rename *ren2,
 879                                         const char *branch2)
 880 {
 881         /* Two files were renamed to the same thing. */
 882         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 883         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 884         output(o, 1, "Renaming %s to %s and %s to %s instead",
 885                ren1->pair->one->path, new_path1,
 886                ren2->pair->one->path, new_path2);
 887         remove_file(o, 0, ren1->pair->two->path, 0);
 888         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 889         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 890         free(new_path2);
 891         free(new_path1);
 892 }
 893
 894 static int process_renames(struct merge_options *o,
 895                            struct string_list *a_renames,
 896                            struct string_list *b_renames)
 897 {
 898         int clean_merge = 1, i, j;
 899         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 900         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 901         const struct rename *sre;
 902
 903         for (i = 0; i < a_renames->nr; i++) {
 904                 sre = a_renames->items[i].util;
 905                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 906                         = sre->dst_entry;
 907         }
 908         for (i = 0; i < b_renames->nr; i++) {
 909                 sre = b_renames->items[i].util;
 910                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 911                         = sre->dst_entry;
 912         }
 913
 914         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 915                 char *src;
 916                 struct string_list *renames1, *renames2Dst;
 917                 struct rename *ren1 = NULL, *ren2 = NULL;
 918                 const char *branch1, *branch2;
 919                 const char *ren1_src, *ren1_dst;
 920
 921                 if (i >= a_renames->nr) {
 922                         ren2 = b_renames->items[j++].util;
 923                 } else if (j >= b_renames->nr) {
 924                         ren1 = a_renames->items[i++].util;
 925                 } else {
 926                         int compare = strcmp(a_renames->items[i].string,
 927                                              b_renames->items[j].string);
 928                         if (compare <= 0)
 929                                 ren1 = a_renames->items[i++].util;
 930                         if (compare >= 0)
 931                                 ren2 = b_renames->items[j++].util;
 932                 }
 933
 934                 /* TODO: refactor, so that 1/2 are not needed */
 935                 if (ren1) {
 936                         renames1 = a_renames;
 937                         renames2Dst = &b_by_dst;
 938                         branch1 = o->branch1;
 939                         branch2 = o->branch2;
 940                 } else {
 941                         struct rename *tmp;
 942                         renames1 = b_renames;
 943                         renames2Dst = &a_by_dst;
 944                         branch1 = o->branch2;
 945                         branch2 = o->branch1;
 946                         tmp = ren2;
 947                         ren2 = ren1;
 948                         ren1 = tmp;
 949                 }
 950                 src = ren1->pair->one->path;
 951
 952                 ren1->dst_entry->processed = 1;
 953                 ren1->src_entry->processed = 1;
 954
 955                 if (ren1->processed)
 956                         continue;
 957                 ren1->processed = 1;
 958
 959                 ren1_src = ren1->pair->one->path;
 960                 ren1_dst = ren1->pair->two->path;
 961
 962                 if (ren2) {
 963                         const char *ren2_src = ren2->pair->one->path;
 964                         const char *ren2_dst = ren2->pair->two->path;
 965                         /* Renamed in 1 and renamed in 2 */
 966                         if (strcmp(ren1_src, ren2_src) != 0)
 967                                 die("ren1.src != ren2.src");
 968                         ren2->dst_entry->processed = 1;
 969                         ren2->processed = 1;
 970                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 971                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
 972                                                               ren1->pair,
 973                                                               ren2->pair,
 974                                                               branch1,
 975                                                               branch2,
 976                                                               ren1->dst_entry,
 977                                                               ren2->dst_entry);
 978                                 remove_file(o, 0, ren1_dst, 0);
 979                                 /* ren2_dst not in head, so no need to delete */
 980                         } else {
 981                                 remove_file(o, 1, ren1_src, 1);
 982                                 update_stages_and_entry(ren1_dst,
 983                                                         ren1->dst_entry,
 984                                                         ren1->pair->one,
 985                                                         ren1->pair->two,
 986                                                         ren2->pair->two,
 987                                                         1 /* clear */);
 988                         }
 989                 } else {
 990                         /* Renamed in 1, maybe changed in 2 */
 991                         struct string_list_item *item;
 992                         /* we only use sha1 and mode of these */
 993                         struct diff_filespec src_other, dst_other;
 994                         int try_merge;
 995
 996                         /*
 997                          * unpack_trees loads entries from common-commit
 998                          * into stage 1, from head-commit into stage 2, and
 999                          * from merge-commit into stage 3.  We keep track
1000                          * of which side corresponds to the rename.
1001                          */
1002                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1003                         int other_stage =   a_renames == renames1 ? 3 : 2;
1004
1005                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
1006
1007                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1008                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1009                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1010                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1011                         try_merge = 0;
1012
1013                         if (sha_eq(src_other.sha1, null_sha1)) {
1014                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1015                                         ren1->dst_entry->processed = 0;
1016                                         setup_rename_df_conflict_info(RENAME_DELETE,
1017                                                                       ren1->pair,
1018                                                                       NULL,
1019                                                                       branch1,
1020                                                                       branch2,
1021                                                                       ren1->dst_entry,
1022                                                                       NULL);
1023                                         remove_file(o, 0, ren1_dst, 0);
1024                                 } else {
1025                                         clean_merge = 0;
1026                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1027                                 }
1028                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1029                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1030                                 /* Added file on the other side
1031                                    identical to the file being
1032                                    renamed: clean merge */
1033                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1034                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1035                                 const char *new_path;
1036                                 clean_merge = 0;
1037                                 try_merge = 1;
1038                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1039                                        "%s added in %s",
1040                                        ren1_src, ren1_dst, branch1,
1041                                        ren1_dst, branch2);
1042                                 if (o->call_depth) {
1043                                         struct merge_file_info mfi;
1044                                         struct diff_filespec one, a, b;
1045
1046                                         one.path = a.path = b.path =
1047                                                 (char *)ren1_dst;
1048                                         hashcpy(one.sha1, null_sha1);
1049                                         one.mode = 0;
1050                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1051                                         a.mode = ren1->pair->two->mode;
1052                                         hashcpy(b.sha1, dst_other.sha1);
1053                                         b.mode = dst_other.mode;
1054                                         mfi = merge_file(o, &one, &a, &b,
1055                                                          branch1,
1056                                                          branch2);
1057                                         output(o, 1, "Adding merged %s", ren1_dst);
1058                                         update_file(o, 0,
1059                                                     mfi.sha,
1060                                                     mfi.mode,
1061                                                     ren1_dst);
1062                                         try_merge = 0;
1063                                 } else {
1064                                         new_path = unique_path(o, ren1_dst, branch2);
1065                                         output(o, 1, "Adding as %s instead", new_path);
1066                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1067                                 }
1068                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1069                                 ren2 = item->util;
1070                                 clean_merge = 0;
1071                                 ren2->processed = 1;
1072                                 output(o, 1, "CONFLICT (rename/rename): "
1073                                        "Rename %s->%s in %s. "
1074                                        "Rename %s->%s in %s",
1075                                        ren1_src, ren1_dst, branch1,
1076                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1077                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1078                         } else
1079                                 try_merge = 1;
1080
1081                         if (try_merge) {
1082                                 struct diff_filespec *one, *a, *b;
1083                                 src_other.path = (char *)ren1_src;
1084
1085                                 one = ren1->pair->one;
1086                                 if (a_renames == renames1) {
1087                                         a = ren1->pair->two;
1088                                         b = &src_other;
1089                                 } else {
1090                                         b = ren1->pair->two;
1091                                         a = &src_other;
1092                                 }
1093                                 update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
1094                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1095                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1096                                                                       ren1->pair,
1097                                                                       NULL,
1098                                                                       branch1,
1099                                                                       NULL,
1100                                                                       ren1->dst_entry,
1101                                                                       NULL);
1102                                         remove_file(o, 0, ren1_dst, 0);
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                                  const char *new_path,
1168                                  unsigned char *a_sha, int a_mode,
1169                                  unsigned char *b_sha, int b_mode)
1170 {
1171         if (!a_sha) {
1172                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1173                        "and modified in %s. Version %s of %s left in tree%s%s.",
1174                        path, o->branch1,
1175                        o->branch2, o->branch2, path,
1176                        path == new_path ? "" : " at ",
1177                        path == new_path ? "" : new_path);
1178                 update_file(o, 0, b_sha, b_mode, new_path);
1179         } else {
1180                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1181                        "and modified in %s. Version %s of %s left in tree%s%s.",
1182                        path, o->branch2,
1183                        o->branch1, o->branch1, path,
1184                        path == new_path ? "" : " at ",
1185                        path == new_path ? "" : new_path);
1186                 update_file(o, 0, a_sha, a_mode, new_path);
1187         }
1188 }
1189
1190 static int merge_content(struct merge_options *o,
1191                          const char *path,
1192                          unsigned char *o_sha, int o_mode,
1193                          unsigned char *a_sha, int a_mode,
1194                          unsigned char *b_sha, int b_mode,
1195                          const char *df_rename_conflict_branch)
1196 {
1197         const char *reason = "content";
1198         struct merge_file_info mfi;
1199         struct diff_filespec one, a, b;
1200         struct stat st;
1201         unsigned df_conflict_remains = 0;
1202
1203         if (!o_sha) {
1204                 reason = "add/add";
1205                 o_sha = (unsigned char *)null_sha1;
1206         }
1207         one.path = a.path = b.path = (char *)path;
1208         hashcpy(one.sha1, o_sha);
1209         one.mode = o_mode;
1210         hashcpy(a.sha1, a_sha);
1211         a.mode = a_mode;
1212         hashcpy(b.sha1, b_sha);
1213         b.mode = b_mode;
1214
1215         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1216         if (df_rename_conflict_branch &&
1217             lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1218                 df_conflict_remains = 1;
1219         }
1220
1221         if (mfi.clean && !df_conflict_remains &&
1222             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1223                 output(o, 3, "Skipped %s (merged same as existing)", path);
1224         else
1225                 output(o, 2, "Auto-merging %s", path);
1226
1227         if (!mfi.clean) {
1228                 if (S_ISGITLINK(mfi.mode))
1229                         reason = "submodule";
1230                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1231                                 reason, path);
1232         }
1233
1234         if (df_conflict_remains) {
1235                 const char *new_path;
1236                 update_file_flags(o, mfi.sha, mfi.mode, path,
1237                                   o->call_depth || mfi.clean, 0);
1238                 new_path = unique_path(o, path, df_rename_conflict_branch);
1239                 mfi.clean = 0;
1240                 output(o, 1, "Adding as %s instead", new_path);
1241                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1242         } else {
1243                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1244         }
1245         return mfi.clean;
1246
1247 }
1248
1249 /* Per entry merge function */
1250 static int process_entry(struct merge_options *o,
1251                          const char *path, struct stage_data *entry)
1252 {
1253         /*
1254         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1255         print_index_entry("\tpath: ", entry);
1256         */
1257         int clean_merge = 1;
1258         int normalize = o->renormalize;
1259         unsigned o_mode = entry->stages[1].mode;
1260         unsigned a_mode = entry->stages[2].mode;
1261         unsigned b_mode = entry->stages[3].mode;
1262         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1263         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1264         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1265
1266         if (entry->rename_df_conflict_info)
1267                 return 1; /* Such cases are handled elsewhere. */
1268
1269         entry->processed = 1;
1270         if (o_sha && (!a_sha || !b_sha)) {
1271                 /* Case A: Deleted in one */
1272                 if ((!a_sha && !b_sha) ||
1273                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1274                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1275                         /* Deleted in both or deleted in one and
1276                          * unchanged in the other */
1277                         if (a_sha)
1278                                 output(o, 2, "Removing %s", path);
1279                         /* do not touch working file if it did not exist */
1280                         remove_file(o, 1, path, !a_sha);
1281                 } else if (string_list_has_string(&o->current_directory_set,
1282                                                   path)) {
1283                         entry->processed = 0;
1284                         return 1; /* Assume clean till processed */
1285                 } else {
1286                         /* Deleted in one and changed in the other */
1287                         clean_merge = 0;
1288                         handle_delete_modify(o, path, path,
1289                                              a_sha, a_mode, b_sha, b_mode);
1290                 }
1291
1292         } else if ((!o_sha && a_sha && !b_sha) ||
1293                    (!o_sha && !a_sha && b_sha)) {
1294                 /* Case B: Added in one. */
1295                 unsigned mode;
1296                 const unsigned char *sha;
1297
1298                 if (a_sha) {
1299                         mode = a_mode;
1300                         sha = a_sha;
1301                 } else {
1302                         mode = b_mode;
1303                         sha = b_sha;
1304                 }
1305                 if (string_list_has_string(&o->current_directory_set, path)) {
1306                         /* Handle D->F conflicts after all subfiles */
1307                         entry->processed = 0;
1308                         /* But get any file out of the way now, so conflicted
1309                          * entries below the directory of the same name can
1310                          * be put in the working directory.
1311                          */
1312                         if (a_sha)
1313                                 output(o, 2, "Removing %s", path);
1314                         /* do not touch working file if it did not exist */
1315                         remove_file(o, 0, path, !a_sha);
1316                         return 1; /* Assume clean till processed */
1317                 } else {
1318                         output(o, 2, "Adding %s", path);
1319                         update_file(o, 1, sha, mode, path);
1320                 }
1321         } else if (a_sha && b_sha) {
1322                 /* Case C: Added in both (check for same permissions) and */
1323                 /* case D: Modified in both, but differently. */
1324                 clean_merge = merge_content(o, path,
1325                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1326                                             NULL);
1327         } else if (!o_sha && !a_sha && !b_sha) {
1328                 /*
1329                  * this entry was deleted altogether. a_mode == 0 means
1330                  * we had that path and want to actively remove it.
1331                  */
1332                 remove_file(o, 1, path, !a_mode);
1333         } else
1334                 die("Fatal merge failure, shouldn't happen.");
1335
1336         return clean_merge;
1337 }
1338
1339 /*
1340  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1341  * cases we can cleanly resolve D/F conflicts, process_entry() can
1342  * clean out all the files below the directory for us.  All D/F
1343  * conflict cases must be handled here at the end to make sure any
1344  * directories that can be cleaned out, are.
1345  *
1346  * Some rename conflicts may also be handled here that don't necessarily
1347  * involve D/F conflicts, since the code to handle them is generic enough
1348  * to handle those rename conflicts with or without D/F conflicts also
1349  * being involved.
1350  */
1351 static int process_df_entry(struct merge_options *o,
1352                             const char *path, struct stage_data *entry)
1353 {
1354         int clean_merge = 1;
1355         unsigned o_mode = entry->stages[1].mode;
1356         unsigned a_mode = entry->stages[2].mode;
1357         unsigned b_mode = entry->stages[3].mode;
1358         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1359         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1360         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1361         struct stat st;
1362
1363         entry->processed = 1;
1364         if (entry->rename_df_conflict_info) {
1365                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1366                 char *src;
1367                 switch (conflict_info->rename_type) {
1368                 case RENAME_NORMAL:
1369                         clean_merge = merge_content(o, path,
1370                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1371                                                     conflict_info->branch1);
1372                         break;
1373                 case RENAME_DELETE:
1374                         clean_merge = 0;
1375                         conflict_rename_delete(o, conflict_info->pair1,
1376                                                conflict_info->branch1,
1377                                                conflict_info->branch2);
1378                         break;
1379                 case RENAME_ONE_FILE_TO_TWO:
1380                         src = conflict_info->pair1->one->path;
1381                         clean_merge = 0;
1382                         output(o, 1, "CONFLICT (rename/rename): "
1383                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1384                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1385                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1386                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1387                                o->call_depth ? " (left unresolved)" : "");
1388                         if (o->call_depth) {
1389                                 remove_file_from_cache(src);
1390                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1391                                             conflict_info->pair1->one->mode, src);
1392                         }
1393                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1394                                                     conflict_info->branch1,
1395                                                     conflict_info->pair2,
1396                                                     conflict_info->branch2);
1397                         conflict_info->dst_entry2->processed = 1;
1398                         break;
1399                 default:
1400                         entry->processed = 0;
1401                         break;
1402                 }
1403         } else if (o_sha && (!a_sha || !b_sha)) {
1404                 /* Modify/delete; deleted side may have put a directory in the way */
1405                 const char *new_path = path;
1406                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode))
1407                         new_path = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1408                 clean_merge = 0;
1409                 handle_delete_modify(o, path, new_path,
1410                                      a_sha, a_mode, b_sha, b_mode);
1411         } else if (!o_sha && !!a_sha != !!b_sha) {
1412                 /* directory -> (directory, file) */
1413                 const char *add_branch;
1414                 const char *other_branch;
1415                 unsigned mode;
1416                 const unsigned char *sha;
1417                 const char *conf;
1418
1419                 if (a_sha) {
1420                         add_branch = o->branch1;
1421                         other_branch = o->branch2;
1422                         mode = a_mode;
1423                         sha = a_sha;
1424                         conf = "file/directory";
1425                 } else {
1426                         add_branch = o->branch2;
1427                         other_branch = o->branch1;
1428                         mode = b_mode;
1429                         sha = b_sha;
1430                         conf = "directory/file";
1431                 }
1432                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1433                         const char *new_path = unique_path(o, path, add_branch);
1434                         clean_merge = 0;
1435                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1436                                "Adding %s as %s",
1437                                conf, path, other_branch, path, new_path);
1438                         remove_file(o, 0, path, 0);
1439                         update_file(o, 0, sha, mode, new_path);
1440                 } else {
1441                         output(o, 2, "Adding %s", path);
1442                         update_file(o, 1, sha, mode, path);
1443                 }
1444         } else {
1445                 entry->processed = 0;
1446                 return 1; /* not handled; assume clean until processed */
1447         }
1448
1449         return clean_merge;
1450 }
1451
1452 int merge_trees(struct merge_options *o,
1453                 struct tree *head,
1454                 struct tree *merge,
1455                 struct tree *common,
1456                 struct tree **result)
1457 {
1458         int code, clean;
1459
1460         if (o->subtree_shift) {
1461                 merge = shift_tree_object(head, merge, o->subtree_shift);
1462                 common = shift_tree_object(head, common, o->subtree_shift);
1463         }
1464
1465         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1466                 output(o, 0, "Already up-to-date!");
1467                 *result = head;
1468                 return 1;
1469         }
1470
1471         code = git_merge_trees(o->call_depth, common, head, merge);
1472
1473         if (code != 0) {
1474                 if (show(o, 4) || o->call_depth)
1475                         die("merging of trees %s and %s failed",
1476                             sha1_to_hex(head->object.sha1),
1477                             sha1_to_hex(merge->object.sha1));
1478                 else
1479                         exit(128);
1480         }
1481
1482         if (unmerged_cache()) {
1483                 struct string_list *entries, *re_head, *re_merge;
1484                 int i;
1485                 string_list_clear(&o->current_file_set, 1);
1486                 string_list_clear(&o->current_directory_set, 1);
1487                 get_files_dirs(o, head);
1488                 get_files_dirs(o, merge);
1489
1490                 entries = get_unmerged();
1491                 re_head  = get_renames(o, head, common, head, merge, entries);
1492                 re_merge = get_renames(o, merge, common, head, merge, entries);
1493                 clean = process_renames(o, re_head, re_merge);
1494                 for (i = 0; i < entries->nr; i++) {
1495                         const char *path = entries->items[i].string;
1496                         struct stage_data *e = entries->items[i].util;
1497                         if (!e->processed
1498                                 && !process_entry(o, path, e))
1499                                 clean = 0;
1500                 }
1501                 for (i = 0; i < entries->nr; i++) {
1502                         const char *path = entries->items[i].string;
1503                         struct stage_data *e = entries->items[i].util;
1504                         if (!e->processed
1505                                 && !process_df_entry(o, path, e))
1506                                 clean = 0;
1507                 }
1508                 for (i = 0; i < entries->nr; i++) {
1509                         struct stage_data *e = entries->items[i].util;
1510                         if (!e->processed)
1511                                 die("Unprocessed path??? %s",
1512                                     entries->items[i].string);
1513                 }
1514
1515                 string_list_clear(re_merge, 0);
1516                 string_list_clear(re_head, 0);
1517                 string_list_clear(entries, 1);
1518
1519         }
1520         else
1521                 clean = 1;
1522
1523         if (o->call_depth)
1524                 *result = write_tree_from_memory(o);
1525
1526         return clean;
1527 }
1528
1529 static struct commit_list *reverse_commit_list(struct commit_list *list)
1530 {
1531         struct commit_list *next = NULL, *current, *backup;
1532         for (current = list; current; current = backup) {
1533                 backup = current->next;
1534                 current->next = next;
1535                 next = current;
1536         }
1537         return next;
1538 }
1539
1540 /*
1541  * Merge the commits h1 and h2, return the resulting virtual
1542  * commit object and a flag indicating the cleanness of the merge.
1543  */
1544 int merge_recursive(struct merge_options *o,
1545                     struct commit *h1,
1546                     struct commit *h2,
1547                     struct commit_list *ca,
1548                     struct commit **result)
1549 {
1550         struct commit_list *iter;
1551         struct commit *merged_common_ancestors;
1552         struct tree *mrtree = mrtree;
1553         int clean;
1554
1555         if (show(o, 4)) {
1556                 output(o, 4, "Merging:");
1557                 output_commit_title(o, h1);
1558                 output_commit_title(o, h2);
1559         }
1560
1561         if (!ca) {
1562                 ca = get_merge_bases(h1, h2, 1);
1563                 ca = reverse_commit_list(ca);
1564         }
1565
1566         if (show(o, 5)) {
1567                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1568                 for (iter = ca; iter; iter = iter->next)
1569                         output_commit_title(o, iter->item);
1570         }
1571
1572         merged_common_ancestors = pop_commit(&ca);
1573         if (merged_common_ancestors == NULL) {
1574                 /* if there is no common ancestor, make an empty tree */
1575                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1576
1577                 tree->object.parsed = 1;
1578                 tree->object.type = OBJ_TREE;
1579                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1580                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1581         }
1582
1583         for (iter = ca; iter; iter = iter->next) {
1584                 const char *saved_b1, *saved_b2;
1585                 o->call_depth++;
1586                 /*
1587                  * When the merge fails, the result contains files
1588                  * with conflict markers. The cleanness flag is
1589                  * ignored, it was never actually used, as result of
1590                  * merge_trees has always overwritten it: the committed
1591                  * "conflicts" were already resolved.
1592                  */
1593                 discard_cache();
1594                 saved_b1 = o->branch1;
1595                 saved_b2 = o->branch2;
1596                 o->branch1 = "Temporary merge branch 1";
1597                 o->branch2 = "Temporary merge branch 2";
1598                 merge_recursive(o, merged_common_ancestors, iter->item,
1599                                 NULL, &merged_common_ancestors);
1600                 o->branch1 = saved_b1;
1601                 o->branch2 = saved_b2;
1602                 o->call_depth--;
1603
1604                 if (!merged_common_ancestors)
1605                         die("merge returned no commit");
1606         }
1607
1608         discard_cache();
1609         if (!o->call_depth)
1610                 read_cache();
1611
1612         o->ancestor = "merged common ancestors";
1613         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1614                             &mrtree);
1615
1616         if (o->call_depth) {
1617                 *result = make_virtual_commit(mrtree, "merged tree");
1618                 commit_list_insert(h1, &(*result)->parents);
1619                 commit_list_insert(h2, &(*result)->parents->next);
1620         }
1621         flush_output(o);
1622         return clean;
1623 }
1624
1625 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1626 {
1627         struct object *object;
1628
1629         object = deref_tag(parse_object(sha1), name, strlen(name));
1630         if (!object)
1631                 return NULL;
1632         if (object->type == OBJ_TREE)
1633                 return make_virtual_commit((struct tree*)object, name);
1634         if (object->type != OBJ_COMMIT)
1635                 return NULL;
1636         if (parse_commit((struct commit *)object))
1637                 return NULL;
1638         return (struct commit *)object;
1639 }
1640
1641 int merge_recursive_generic(struct merge_options *o,
1642                             const unsigned char *head,
1643                             const unsigned char *merge,
1644                             int num_base_list,
1645                             const unsigned char **base_list,
1646                             struct commit **result)
1647 {
1648         int clean, index_fd;
1649         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1650         struct commit *head_commit = get_ref(head, o->branch1);
1651         struct commit *next_commit = get_ref(merge, o->branch2);
1652         struct commit_list *ca = NULL;
1653
1654         if (base_list) {
1655                 int i;
1656                 for (i = 0; i < num_base_list; ++i) {
1657                         struct commit *base;
1658                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1659                                 return error("Could not parse object '%s'",
1660                                         sha1_to_hex(base_list[i]));
1661                         commit_list_insert(base, &ca);
1662                 }
1663         }
1664
1665         index_fd = hold_locked_index(lock, 1);
1666         clean = merge_recursive(o, head_commit, next_commit, ca,
1667                         result);
1668         if (active_cache_changed &&
1669                         (write_cache(index_fd, active_cache, active_nr) ||
1670                          commit_locked_index(lock)))
1671                 return error("Unable to write index.");
1672
1673         return clean ? 0 : 1;
1674 }
1675
1676 static int merge_recursive_config(const char *var, const char *value, void *cb)
1677 {
1678         struct merge_options *o = cb;
1679         if (!strcasecmp(var, "merge.verbosity")) {
1680                 o->verbosity = git_config_int(var, value);
1681                 return 0;
1682         }
1683         if (!strcasecmp(var, "diff.renamelimit")) {
1684                 o->diff_rename_limit = git_config_int(var, value);
1685                 return 0;
1686         }
1687         if (!strcasecmp(var, "merge.renamelimit")) {
1688                 o->merge_rename_limit = git_config_int(var, value);
1689                 return 0;
1690         }
1691         return git_xmerge_config(var, value, cb);
1692 }
1693
1694 void init_merge_options(struct merge_options *o)
1695 {
1696         memset(o, 0, sizeof(struct merge_options));
1697         o->verbosity = 2;
1698         o->buffer_output = 1;
1699         o->diff_rename_limit = -1;
1700         o->merge_rename_limit = -1;
1701         o->renormalize = 0;
1702         git_config(merge_recursive_config, o);
1703         if (getenv("GIT_MERGE_VERBOSITY"))
1704                 o->verbosity =
1705                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1706         if (o->verbosity >= 5)
1707                 o->buffer_output = 0;
1708         strbuf_init(&o->obuf, 0);
1709         memset(&o->current_file_set, 0, sizeof(struct string_list));
1710         o->current_file_set.strdup_strings = 1;
1711         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1712         o->current_directory_set.strdup_strings = 1;
1713 }