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         struct {
  88                 unsigned mode;
  89                 unsigned char sha[20];
  90         } stages[4];
  91         struct rename_df_conflict_info *rename_df_conflict_info;
  92         unsigned processed:1;
  93         unsigned involved_in_rename:1;
  94 };
  95
  96 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
  97                                                  struct diff_filepair *pair1,
  98                                                  struct diff_filepair *pair2,
  99                                                  const char *branch1,
 100                                                  const char *branch2,
 101                                                  struct stage_data *dst_entry1,
 102                                                  struct stage_data *dst_entry2)
 103 {
 104         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
 105         ci->rename_type = rename_type;
 106         ci->pair1 = pair1;
 107         ci->branch1 = branch1;
 108         ci->branch2 = branch2;
 109
 110         ci->dst_entry1 = dst_entry1;
 111         dst_entry1->rename_df_conflict_info = ci;
 112         dst_entry1->processed = 0;
 113
 114         assert(!pair2 == !dst_entry2);
 115         if (dst_entry2) {
 116                 ci->dst_entry2 = dst_entry2;
 117                 ci->pair2 = pair2;
 118                 dst_entry2->rename_df_conflict_info = ci;
 119                 dst_entry2->processed = 0;
 120         }
 121 }
 122
 123 static int show(struct merge_options *o, int v)
 124 {
 125         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 126 }
 127
 128 static void flush_output(struct merge_options *o)
 129 {
 130         if (o->obuf.len) {
 131                 fputs(o->obuf.buf, stdout);
 132                 strbuf_reset(&o->obuf);
 133         }
 134 }
 135
 136 __attribute__((format (printf, 3, 4)))
 137 static void output(struct merge_options *o, int v, const char *fmt, ...)
 138 {
 139         va_list ap;
 140
 141         if (!show(o, v))
 142                 return;
 143
 144         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 145         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 146         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 147
 148         va_start(ap, fmt);
 149         strbuf_vaddf(&o->obuf, fmt, ap);
 150         va_end(ap);
 151
 152         strbuf_add(&o->obuf, "\n", 1);
 153         if (!o->buffer_output)
 154                 flush_output(o);
 155 }
 156
 157 static void output_commit_title(struct merge_options *o, struct commit *commit)
 158 {
 159         int i;
 160         flush_output(o);
 161         for (i = o->call_depth; i--;)
 162                 fputs("  ", stdout);
 163         if (commit->util)
 164                 printf("virtual %s\n", (char *)commit->util);
 165         else {
 166                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 167                 if (parse_commit(commit) != 0)
 168                         printf("(bad commit)\n");
 169                 else {
 170                         const char *title;
 171                         int len = find_commit_subject(commit->buffer, &title);
 172                         if (len)
 173                                 printf("%.*s\n", len, title);
 174                 }
 175         }
 176 }
 177
 178 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 179                 const char *path, int stage, int refresh, int options)
 180 {
 181         struct cache_entry *ce;
 182         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 183         if (!ce)
 184                 return error("addinfo_cache failed for path '%s'", path);
 185         return add_cache_entry(ce, options);
 186 }
 187
 188 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 189 {
 190         parse_tree(tree);
 191         init_tree_desc(desc, tree->buffer, tree->size);
 192 }
 193
 194 static int git_merge_trees(int index_only,
 195                            struct tree *common,
 196                            struct tree *head,
 197                            struct tree *merge)
 198 {
 199         int rc;
 200         struct tree_desc t[3];
 201         struct unpack_trees_options opts;
 202
 203         memset(&opts, 0, sizeof(opts));
 204         if (index_only)
 205                 opts.index_only = 1;
 206         else
 207                 opts.update = 1;
 208         opts.merge = 1;
 209         opts.head_idx = 2;
 210         opts.fn = threeway_merge;
 211         opts.src_index = &the_index;
 212         opts.dst_index = &the_index;
 213         setup_unpack_trees_porcelain(&opts, "merge");
 214
 215         init_tree_desc_from_tree(t+0, common);
 216         init_tree_desc_from_tree(t+1, head);
 217         init_tree_desc_from_tree(t+2, merge);
 218
 219         rc = unpack_trees(3, t, &opts);
 220         cache_tree_free(&active_cache_tree);
 221         return rc;
 222 }
 223
 224 struct tree *write_tree_from_memory(struct merge_options *o)
 225 {
 226         struct tree *result = NULL;
 227
 228         if (unmerged_cache()) {
 229                 int i;
 230                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 231                 for (i = 0; i < active_nr; i++) {
 232                         struct cache_entry *ce = active_cache[i];
 233                         if (ce_stage(ce))
 234                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 235                                         (int)ce_namelen(ce), ce->name);
 236                 }
 237                 die("Bug in merge-recursive.c");
 238         }
 239
 240         if (!active_cache_tree)
 241                 active_cache_tree = cache_tree();
 242
 243         if (!cache_tree_fully_valid(active_cache_tree) &&
 244             cache_tree_update(active_cache_tree,
 245                               active_cache, active_nr, 0, 0) < 0)
 246                 die("error building trees");
 247
 248         result = lookup_tree(active_cache_tree->sha1);
 249
 250         return result;
 251 }
 252
 253 static int save_files_dirs(const unsigned char *sha1,
 254                 const char *base, int baselen, const char *path,
 255                 unsigned int mode, int stage, void *context)
 256 {
 257         int len = strlen(path);
 258         char *newpath = xmalloc(baselen + len + 1);
 259         struct merge_options *o = context;
 260
 261         memcpy(newpath, base, baselen);
 262         memcpy(newpath + baselen, path, len);
 263         newpath[baselen + len] = '\0';
 264
 265         if (S_ISDIR(mode))
 266                 string_list_insert(&o->current_directory_set, newpath);
 267         else
 268                 string_list_insert(&o->current_file_set, newpath);
 269         free(newpath);
 270
 271         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 272 }
 273
 274 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 275 {
 276         int n;
 277         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 278                 return 0;
 279         n = o->current_file_set.nr + o->current_directory_set.nr;
 280         return n;
 281 }
 282
 283 /*
 284  * Returns an index_entry instance which doesn't have to correspond to
 285  * a real cache entry in Git's index.
 286  */
 287 static struct stage_data *insert_stage_data(const char *path,
 288                 struct tree *o, struct tree *a, struct tree *b,
 289                 struct string_list *entries)
 290 {
 291         struct string_list_item *item;
 292         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 293         get_tree_entry(o->object.sha1, path,
 294                         e->stages[1].sha, &e->stages[1].mode);
 295         get_tree_entry(a->object.sha1, path,
 296                         e->stages[2].sha, &e->stages[2].mode);
 297         get_tree_entry(b->object.sha1, path,
 298                         e->stages[3].sha, &e->stages[3].mode);
 299         item = string_list_insert(entries, path);
 300         item->util = e;
 301         return e;
 302 }
 303
 304 /*
 305  * Create a dictionary mapping file names to stage_data objects. The
 306  * dictionary contains one entry for every path with a non-zero stage entry.
 307  */
 308 static struct string_list *get_unmerged(void)
 309 {
 310         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 311         int i;
 312
 313         unmerged->strdup_strings = 1;
 314
 315         for (i = 0; i < active_nr; i++) {
 316                 struct string_list_item *item;
 317                 struct stage_data *e;
 318                 struct cache_entry *ce = active_cache[i];
 319                 if (!ce_stage(ce))
 320                         continue;
 321
 322                 item = string_list_lookup(unmerged, ce->name);
 323                 if (!item) {
 324                         item = string_list_insert(unmerged, ce->name);
 325                         item->util = xcalloc(1, sizeof(struct stage_data));
 326                 }
 327                 e = item->util;
 328                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 329                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 330         }
 331
 332         return unmerged;
 333 }
 334
 335 static int string_list_df_name_compare(const void *a, const void *b)
 336 {
 337         const struct string_list_item *one = a;
 338         const struct string_list_item *two = b;
 339         int onelen = strlen(one->string);
 340         int twolen = strlen(two->string);
 341         /*
 342          * Here we only care that entries for D/F conflicts are
 343          * adjacent, in particular with the file of the D/F conflict
 344          * appearing before files below the corresponding directory.
 345          * The order of the rest of the list is irrelevant for us.
 346          *
 347          * To achieve this, we sort with df_name_compare and provide
 348          * the mode S_IFDIR so that D/F conflicts will sort correctly.
 349          * We use the mode S_IFDIR for everything else for simplicity,
 350          * since in other cases any changes in their order due to
 351          * sorting cause no problems for us.
 352          */
 353         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
 354                                   two->string, twolen, S_IFDIR);
 355         /*
 356          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 357          * that 'foo' comes before 'foo/bar'.
 358          */
 359         if (cmp)
 360                 return cmp;
 361         return onelen - twolen;
 362 }
 363
 364 static void record_df_conflict_files(struct merge_options *o,
 365                                      struct string_list *entries)
 366 {
 367         /* If there is a D/F conflict and the file for such a conflict
 368          * currently exist in the working copy, we want to allow it to
 369          * be removed to make room for the corresponding directory if
 370          * needed.  The files underneath the directories of such D/F
 371          * conflicts will be handled in process_entry(), while the
 372          * files of such D/F conflicts will be processed later in
 373          * process_df_entry().  If the corresponding directory ends up
 374          * being removed by the merge, then no additional work needs
 375          * to be done by process_df_entry() for the conflicting file.
 376          * If the directory needs to be written to the working copy,
 377          * then the conflicting file will simply be removed (e.g. in
 378          * make_room_for_path).  If the directory is written to the
 379          * working copy but the file also has a conflict that needs to
 380          * be resolved, then process_df_entry() will reinstate the
 381          * file with a new unique name.
 382          */
 383         const char *last_file = NULL;
 384         int last_len = 0;
 385         int i;
 386
 387         /*
 388          * If we're merging merge-bases, we don't want to bother with
 389          * any working directory changes.
 390          */
 391         if (o->call_depth)
 392                 return;
 393
 394         /* Ensure D/F conflicts are adjacent in the entries list. */
 395         qsort(entries->items, entries->nr, sizeof(*entries->items),
 396               string_list_df_name_compare);
 397
 398         string_list_clear(&o->df_conflict_file_set, 1);
 399         for (i = 0; i < entries->nr; i++) {
 400                 const char *path = entries->items[i].string;
 401                 int len = strlen(path);
 402                 struct stage_data *e = entries->items[i].util;
 403
 404                 /*
 405                  * Check if last_file & path correspond to a D/F conflict;
 406                  * i.e. whether path is last_file+'/'+<something>.
 407                  * If so, record that it's okay to remove last_file to make
 408                  * room for path and friends if needed.
 409                  */
 410                 if (last_file &&
 411                     len > last_len &&
 412                     memcmp(path, last_file, last_len) == 0 &&
 413                     path[last_len] == '/') {
 414                         string_list_insert(&o->df_conflict_file_set, last_file);
 415                 }
 416
 417                 /*
 418                  * Determine whether path could exist as a file in the
 419                  * working directory as a possible D/F conflict.  This
 420                  * will only occur when it exists in stage 2 as a
 421                  * file.
 422                  */
 423                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 424                         last_file = path;
 425                         last_len = len;
 426                 } else {
 427                         last_file = NULL;
 428                 }
 429         }
 430 }
 431
 432 struct rename {
 433         struct diff_filepair *pair;
 434         struct stage_data *src_entry;
 435         struct stage_data *dst_entry;
 436         unsigned processed:1;
 437 };
 438
 439 /*
 440  * Get information of all renames which occurred between 'o_tree' and
 441  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 442  * 'b_tree') to be able to associate the correct cache entries with
 443  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 444  */
 445 static struct string_list *get_renames(struct merge_options *o,
 446                                        struct tree *tree,
 447                                        struct tree *o_tree,
 448                                        struct tree *a_tree,
 449                                        struct tree *b_tree,
 450                                        struct string_list *entries)
 451 {
 452         int i;
 453         struct string_list *renames;
 454         struct diff_options opts;
 455
 456         renames = xcalloc(1, sizeof(struct string_list));
 457         diff_setup(&opts);
 458         DIFF_OPT_SET(&opts, RECURSIVE);
 459         opts.detect_rename = DIFF_DETECT_RENAME;
 460         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 461                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 462                             1000;
 463         opts.rename_score = o->rename_score;
 464         opts.show_rename_progress = o->show_rename_progress;
 465         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 466         if (diff_setup_done(&opts) < 0)
 467                 die("diff setup failed");
 468         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 469         diffcore_std(&opts);
 470         if (opts.needed_rename_limit > o->needed_rename_limit)
 471                 o->needed_rename_limit = opts.needed_rename_limit;
 472         for (i = 0; i < diff_queued_diff.nr; ++i) {
 473                 struct string_list_item *item;
 474                 struct rename *re;
 475                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 476                 if (pair->status != 'R') {
 477                         diff_free_filepair(pair);
 478                         continue;
 479                 }
 480                 re = xmalloc(sizeof(*re));
 481                 re->processed = 0;
 482                 re->pair = pair;
 483                 item = string_list_lookup(entries, re->pair->one->path);
 484                 if (!item)
 485                         re->src_entry = insert_stage_data(re->pair->one->path,
 486                                         o_tree, a_tree, b_tree, entries);
 487                 else
 488                         re->src_entry = item->util;
 489
 490                 item = string_list_lookup(entries, re->pair->two->path);
 491                 if (!item)
 492                         re->dst_entry = insert_stage_data(re->pair->two->path,
 493                                         o_tree, a_tree, b_tree, entries);
 494                 else
 495                         re->dst_entry = item->util;
 496                 item = string_list_insert(renames, pair->one->path);
 497                 item->util = re;
 498         }
 499         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 500         diff_queued_diff.nr = 0;
 501         diff_flush(&opts);
 502         return renames;
 503 }
 504
 505 static int update_stages(const char *path, const struct diff_filespec *o,
 506                          const struct diff_filespec *a,
 507                          const struct diff_filespec *b)
 508 {
 509         int clear = 1;
 510         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 511         if (clear)
 512                 if (remove_file_from_cache(path))
 513                         return -1;
 514         if (o)
 515                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 516                         return -1;
 517         if (a)
 518                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 519                         return -1;
 520         if (b)
 521                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 522                         return -1;
 523         return 0;
 524 }
 525
 526 static void update_entry(struct stage_data *entry,
 527                          struct diff_filespec *o,
 528                          struct diff_filespec *a,
 529                          struct diff_filespec *b)
 530 {
 531         entry->processed = 0;
 532         entry->stages[1].mode = o->mode;
 533         entry->stages[2].mode = a->mode;
 534         entry->stages[3].mode = b->mode;
 535         hashcpy(entry->stages[1].sha, o->sha1);
 536         hashcpy(entry->stages[2].sha, a->sha1);
 537         hashcpy(entry->stages[3].sha, b->sha1);
 538 }
 539
 540 static int remove_file(struct merge_options *o, int clean,
 541                        const char *path, int no_wd)
 542 {
 543         int update_cache = o->call_depth || clean;
 544         int update_working_directory = !o->call_depth && !no_wd;
 545
 546         if (update_cache) {
 547                 if (remove_file_from_cache(path))
 548                         return -1;
 549         }
 550         if (update_working_directory) {
 551                 if (remove_path(path))
 552                         return -1;
 553         }
 554         return 0;
 555 }
 556
 557 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 558 {
 559         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 560         int suffix = 0;
 561         struct stat st;
 562         char *p = newpath + strlen(path);
 563         strcpy(newpath, path);
 564         *(p++) = '~';
 565         strcpy(p, branch);
 566         for (; *p; ++p)
 567                 if ('/' == *p)
 568                         *p = '_';
 569         while (string_list_has_string(&o->current_file_set, newpath) ||
 570                string_list_has_string(&o->current_directory_set, newpath) ||
 571                lstat(newpath, &st) == 0)
 572                 sprintf(p, "_%d", suffix++);
 573
 574         string_list_insert(&o->current_file_set, newpath);
 575         return newpath;
 576 }
 577
 578 static void flush_buffer(int fd, const char *buf, unsigned long size)
 579 {
 580         while (size > 0) {
 581                 long ret = write_in_full(fd, buf, size);
 582                 if (ret < 0) {
 583                         /* Ignore epipe */
 584                         if (errno == EPIPE)
 585                                 break;
 586                         die_errno("merge-recursive");
 587                 } else if (!ret) {
 588                         die("merge-recursive: disk full?");
 589                 }
 590                 size -= ret;
 591                 buf += ret;
 592         }
 593 }
 594
 595 static int dir_in_way(const char *path, int check_working_copy)
 596 {
 597         int pos, pathlen = strlen(path);
 598         char *dirpath = xmalloc(pathlen + 2);
 599         struct stat st;
 600
 601         strcpy(dirpath, path);
 602         dirpath[pathlen] = '/';
 603         dirpath[pathlen+1] = '\0';
 604
 605         pos = cache_name_pos(dirpath, pathlen+1);
 606
 607         if (pos < 0)
 608                 pos = -1 - pos;
 609         if (pos < active_nr &&
 610             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
 611                 free(dirpath);
 612                 return 1;
 613         }
 614
 615         free(dirpath);
 616         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
 617 }
 618
 619 static int was_tracked(const char *path)
 620 {
 621         int pos = cache_name_pos(path, strlen(path));
 622
 623         if (pos < 0)
 624                 pos = -1 - pos;
 625         while (pos < active_nr &&
 626                !strcmp(path, active_cache[pos]->name)) {
 627                 /*
 628                  * If stage #0, it is definitely tracked.
 629                  * If it has stage #2 then it was tracked
 630                  * before this merge started.  All other
 631                  * cases the path was not tracked.
 632                  */
 633                 switch (ce_stage(active_cache[pos])) {
 634                 case 0:
 635                 case 2:
 636                         return 1;
 637                 }
 638                 pos++;
 639         }
 640         return 0;
 641 }
 642
 643 static int would_lose_untracked(const char *path)
 644 {
 645         return !was_tracked(path) && file_exists(path);
 646 }
 647
 648 static int make_room_for_path(struct merge_options *o, const char *path)
 649 {
 650         int status, i;
 651         const char *msg = "failed to create path '%s'%s";
 652
 653         /* Unlink any D/F conflict files that are in the way */
 654         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 655                 const char *df_path = o->df_conflict_file_set.items[i].string;
 656                 size_t pathlen = strlen(path);
 657                 size_t df_pathlen = strlen(df_path);
 658                 if (df_pathlen < pathlen &&
 659                     path[df_pathlen] == '/' &&
 660                     strncmp(path, df_path, df_pathlen) == 0) {
 661                         output(o, 3,
 662                                "Removing %s to make room for subdirectory\n",
 663                                df_path);
 664                         unlink(df_path);
 665                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
 666                                                          i, 0);
 667                         break;
 668                 }
 669         }
 670
 671         /* Make sure leading directories are created */
 672         status = safe_create_leading_directories_const(path);
 673         if (status) {
 674                 if (status == -3) {
 675                         /* something else exists */
 676                         error(msg, path, ": perhaps a D/F conflict?");
 677                         return -1;
 678                 }
 679                 die(msg, path, "");
 680         }
 681
 682         /*
 683          * Do not unlink a file in the work tree if we are not
 684          * tracking it.
 685          */
 686         if (would_lose_untracked(path))
 687                 return error("refusing to lose untracked file at '%s'",
 688                              path);
 689
 690         /* Successful unlink is good.. */
 691         if (!unlink(path))
 692                 return 0;
 693         /* .. and so is no existing file */
 694         if (errno == ENOENT)
 695                 return 0;
 696         /* .. but not some other error (who really cares what?) */
 697         return error(msg, path, ": perhaps a D/F conflict?");
 698 }
 699
 700 static void update_file_flags(struct merge_options *o,
 701                               const unsigned char *sha,
 702                               unsigned mode,
 703                               const char *path,
 704                               int update_cache,
 705                               int update_wd)
 706 {
 707         if (o->call_depth)
 708                 update_wd = 0;
 709
 710         if (update_wd) {
 711                 enum object_type type;
 712                 void *buf;
 713                 unsigned long size;
 714
 715                 if (S_ISGITLINK(mode)) {
 716                         /*
 717                          * We may later decide to recursively descend into
 718                          * the submodule directory and update its index
 719                          * and/or work tree, but we do not do that now.
 720                          */
 721                         update_wd = 0;
 722                         goto update_index;
 723                 }
 724
 725                 buf = read_sha1_file(sha, &type, &size);
 726                 if (!buf)
 727                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 728                 if (type != OBJ_BLOB)
 729                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 730                 if (S_ISREG(mode)) {
 731                         struct strbuf strbuf = STRBUF_INIT;
 732                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 733                                 free(buf);
 734                                 size = strbuf.len;
 735                                 buf = strbuf_detach(&strbuf, NULL);
 736                         }
 737                 }
 738
 739                 if (make_room_for_path(o, path) < 0) {
 740                         update_wd = 0;
 741                         free(buf);
 742                         goto update_index;
 743                 }
 744                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 745                         int fd;
 746                         if (mode & 0100)
 747                                 mode = 0777;
 748                         else
 749                                 mode = 0666;
 750                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 751                         if (fd < 0)
 752                                 die_errno("failed to open '%s'", path);
 753                         flush_buffer(fd, buf, size);
 754                         close(fd);
 755                 } else if (S_ISLNK(mode)) {
 756                         char *lnk = xmemdupz(buf, size);
 757                         safe_create_leading_directories_const(path);
 758                         unlink(path);
 759                         if (symlink(lnk, path))
 760                                 die_errno("failed to symlink '%s'", path);
 761                         free(lnk);
 762                 } else
 763                         die("do not know what to do with %06o %s '%s'",
 764                             mode, sha1_to_hex(sha), path);
 765                 free(buf);
 766         }
 767  update_index:
 768         if (update_cache)
 769                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 770 }
 771
 772 static void update_file(struct merge_options *o,
 773                         int clean,
 774                         const unsigned char *sha,
 775                         unsigned mode,
 776                         const char *path)
 777 {
 778         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 779 }
 780
 781 /* Low level file merging, update and removal */
 782
 783 struct merge_file_info {
 784         unsigned char sha[20];
 785         unsigned mode;
 786         unsigned clean:1,
 787                  merge:1;
 788 };
 789
 790 static int merge_3way(struct merge_options *o,
 791                       mmbuffer_t *result_buf,
 792                       const struct diff_filespec *one,
 793                       const struct diff_filespec *a,
 794                       const struct diff_filespec *b,
 795                       const char *branch1,
 796                       const char *branch2)
 797 {
 798         mmfile_t orig, src1, src2;
 799         struct ll_merge_options ll_opts = {0};
 800         char *base_name, *name1, *name2;
 801         int merge_status;
 802
 803         ll_opts.renormalize = o->renormalize;
 804         ll_opts.xdl_opts = o->xdl_opts;
 805
 806         if (o->call_depth) {
 807                 ll_opts.virtual_ancestor = 1;
 808                 ll_opts.variant = 0;
 809         } else {
 810                 switch (o->recursive_variant) {
 811                 case MERGE_RECURSIVE_OURS:
 812                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 813                         break;
 814                 case MERGE_RECURSIVE_THEIRS:
 815                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 816                         break;
 817                 default:
 818                         ll_opts.variant = 0;
 819                         break;
 820                 }
 821         }
 822
 823         if (strcmp(a->path, b->path) ||
 824             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 825                 base_name = o->ancestor == NULL ? NULL :
 826                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 827                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 828                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 829         } else {
 830                 base_name = o->ancestor == NULL ? NULL :
 831                         xstrdup(mkpath("%s", o->ancestor));
 832                 name1 = xstrdup(mkpath("%s", branch1));
 833                 name2 = xstrdup(mkpath("%s", branch2));
 834         }
 835
 836         read_mmblob(&orig, one->sha1);
 837         read_mmblob(&src1, a->sha1);
 838         read_mmblob(&src2, b->sha1);
 839
 840         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 841                                 &src1, name1, &src2, name2, &ll_opts);
 842
 843         free(name1);
 844         free(name2);
 845         free(orig.ptr);
 846         free(src1.ptr);
 847         free(src2.ptr);
 848         return merge_status;
 849 }
 850
 851 static struct merge_file_info merge_file(struct merge_options *o,
 852                                          const struct diff_filespec *one,
 853                                          const struct diff_filespec *a,
 854                                          const struct diff_filespec *b,
 855                                          const char *branch1,
 856                                          const char *branch2)
 857 {
 858         struct merge_file_info result;
 859         result.merge = 0;
 860         result.clean = 1;
 861
 862         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 863                 result.clean = 0;
 864                 if (S_ISREG(a->mode)) {
 865                         result.mode = a->mode;
 866                         hashcpy(result.sha, a->sha1);
 867                 } else {
 868                         result.mode = b->mode;
 869                         hashcpy(result.sha, b->sha1);
 870                 }
 871         } else {
 872                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 873                         result.merge = 1;
 874
 875                 /*
 876                  * Merge modes
 877                  */
 878                 if (a->mode == b->mode || a->mode == one->mode)
 879                         result.mode = b->mode;
 880                 else {
 881                         result.mode = a->mode;
 882                         if (b->mode != one->mode) {
 883                                 result.clean = 0;
 884                                 result.merge = 1;
 885                         }
 886                 }
 887
 888                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 889                         hashcpy(result.sha, b->sha1);
 890                 else if (sha_eq(b->sha1, one->sha1))
 891                         hashcpy(result.sha, a->sha1);
 892                 else if (S_ISREG(a->mode)) {
 893                         mmbuffer_t result_buf;
 894                         int merge_status;
 895
 896                         merge_status = merge_3way(o, &result_buf, one, a, b,
 897                                                   branch1, branch2);
 898
 899                         if ((merge_status < 0) || !result_buf.ptr)
 900                                 die("Failed to execute internal merge");
 901
 902                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 903                                             blob_type, result.sha))
 904                                 die("Unable to add %s to database",
 905                                     a->path);
 906
 907                         free(result_buf.ptr);
 908                         result.clean = (merge_status == 0);
 909                 } else if (S_ISGITLINK(a->mode)) {
 910                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 911                                                        a->sha1, b->sha1);
 912                 } else if (S_ISLNK(a->mode)) {
 913                         hashcpy(result.sha, a->sha1);
 914
 915                         if (!sha_eq(a->sha1, b->sha1))
 916                                 result.clean = 0;
 917                 } else {
 918                         die("unsupported object type in the tree");
 919                 }
 920         }
 921
 922         return result;
 923 }
 924
 925 static void conflict_rename_delete(struct merge_options *o,
 926                                    struct diff_filepair *pair,
 927                                    const char *rename_branch,
 928                                    const char *other_branch)
 929 {
 930         char *dest_name = pair->two->path;
 931         int df_conflict = 0;
 932
 933         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 934                "and deleted in %s",
 935                pair->one->path, pair->two->path, rename_branch,
 936                other_branch);
 937         if (!o->call_depth)
 938                 update_stages(dest_name, NULL,
 939                               rename_branch == o->branch1 ? pair->two : NULL,
 940                               rename_branch == o->branch1 ? NULL : pair->two);
 941         if (dir_in_way(dest_name, !o->call_depth)) {
 942                 dest_name = unique_path(o, dest_name, rename_branch);
 943                 df_conflict = 1;
 944         }
 945         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 946         if (df_conflict)
 947                 free(dest_name);
 948 }
 949
 950 static void conflict_rename_rename_1to2(struct merge_options *o,
 951                                         struct diff_filepair *pair1,
 952                                         const char *branch1,
 953                                         struct diff_filepair *pair2,
 954                                         const char *branch2)
 955 {
 956         /* One file was renamed in both branches, but to different names. */
 957         char *del[2];
 958         int delp = 0;
 959         const char *ren1_dst = pair1->two->path;
 960         const char *ren2_dst = pair2->two->path;
 961         const char *dst_name1 = ren1_dst;
 962         const char *dst_name2 = ren2_dst;
 963         if (dir_in_way(ren1_dst, !o->call_depth)) {
 964                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 965                 output(o, 1, "%s is a directory in %s adding as %s instead",
 966                        ren1_dst, branch2, dst_name1);
 967         }
 968         if (dir_in_way(ren2_dst, !o->call_depth)) {
 969                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 970                 output(o, 1, "%s is a directory in %s adding as %s instead",
 971                        ren2_dst, branch1, dst_name2);
 972         }
 973         if (o->call_depth) {
 974                 remove_file_from_cache(dst_name1);
 975                 remove_file_from_cache(dst_name2);
 976                 /*
 977                  * Uncomment to leave the conflicting names in the resulting tree
 978                  *
 979                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 980                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 981                  */
 982         } else {
 983                 update_stages(ren1_dst, NULL, pair1->two, NULL);
 984                 update_stages(ren2_dst, NULL, NULL, pair2->two);
 985
 986                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 987                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 988         }
 989         while (delp--)
 990                 free(del[delp]);
 991 }
 992
 993 static void conflict_rename_rename_2to1(struct merge_options *o,
 994                                         struct rename *ren1,
 995                                         const char *branch1,
 996                                         struct rename *ren2,
 997                                         const char *branch2)
 998 {
 999         /* Two files were renamed to the same thing. */
1000         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
1001         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
1002         output(o, 1, "Renaming %s to %s and %s to %s instead",
1003                ren1->pair->one->path, new_path1,
1004                ren2->pair->one->path, new_path2);
1005         remove_file(o, 0, ren1->pair->two->path, 0);
1006         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
1007         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
1008         free(new_path2);
1009         free(new_path1);
1010 }
1011
1012 static int process_renames(struct merge_options *o,
1013                            struct string_list *a_renames,
1014                            struct string_list *b_renames)
1015 {
1016         int clean_merge = 1, i, j;
1017         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1018         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1019         const struct rename *sre;
1020
1021         for (i = 0; i < a_renames->nr; i++) {
1022                 sre = a_renames->items[i].util;
1023                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1024                         = sre->dst_entry;
1025         }
1026         for (i = 0; i < b_renames->nr; i++) {
1027                 sre = b_renames->items[i].util;
1028                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1029                         = sre->dst_entry;
1030         }
1031
1032         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1033                 struct string_list *renames1, *renames2Dst;
1034                 struct rename *ren1 = NULL, *ren2 = NULL;
1035                 const char *branch1, *branch2;
1036                 const char *ren1_src, *ren1_dst;
1037
1038                 if (i >= a_renames->nr) {
1039                         ren2 = b_renames->items[j++].util;
1040                 } else if (j >= b_renames->nr) {
1041                         ren1 = a_renames->items[i++].util;
1042                 } else {
1043                         int compare = strcmp(a_renames->items[i].string,
1044                                              b_renames->items[j].string);
1045                         if (compare <= 0)
1046                                 ren1 = a_renames->items[i++].util;
1047                         if (compare >= 0)
1048                                 ren2 = b_renames->items[j++].util;
1049                 }
1050
1051                 /* TODO: refactor, so that 1/2 are not needed */
1052                 if (ren1) {
1053                         renames1 = a_renames;
1054                         renames2Dst = &b_by_dst;
1055                         branch1 = o->branch1;
1056                         branch2 = o->branch2;
1057                 } else {
1058                         struct rename *tmp;
1059                         renames1 = b_renames;
1060                         renames2Dst = &a_by_dst;
1061                         branch1 = o->branch2;
1062                         branch2 = o->branch1;
1063                         tmp = ren2;
1064                         ren2 = ren1;
1065                         ren1 = tmp;
1066                 }
1067
1068                 ren1->dst_entry->processed = 1;
1069                 ren1->src_entry->processed = 1;
1070
1071                 if (ren1->processed)
1072                         continue;
1073                 ren1->processed = 1;
1074
1075                 ren1_src = ren1->pair->one->path;
1076                 ren1_dst = ren1->pair->two->path;
1077
1078                 if (ren2) {
1079                         const char *ren2_src = ren2->pair->one->path;
1080                         const char *ren2_dst = ren2->pair->two->path;
1081                         /* Renamed in 1 and renamed in 2 */
1082                         if (strcmp(ren1_src, ren2_src) != 0)
1083                                 die("ren1.src != ren2.src");
1084                         ren2->dst_entry->processed = 1;
1085                         ren2->processed = 1;
1086                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1087                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
1088                                                               ren1->pair,
1089                                                               ren2->pair,
1090                                                               branch1,
1091                                                               branch2,
1092                                                               ren1->dst_entry,
1093                                                               ren2->dst_entry);
1094                         } else {
1095                                 remove_file(o, 1, ren1_src, 1);
1096                                 update_entry(ren1->dst_entry,
1097                                              ren1->pair->one,
1098                                              ren1->pair->two,
1099                                              ren2->pair->two);
1100                                 ren1->dst_entry->involved_in_rename = 1;
1101                         }
1102                 } else {
1103                         /* Renamed in 1, maybe changed in 2 */
1104                         struct string_list_item *item;
1105                         /* we only use sha1 and mode of these */
1106                         struct diff_filespec src_other, dst_other;
1107                         int try_merge;
1108
1109                         /*
1110                          * unpack_trees loads entries from common-commit
1111                          * into stage 1, from head-commit into stage 2, and
1112                          * from merge-commit into stage 3.  We keep track
1113                          * of which side corresponds to the rename.
1114                          */
1115                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1116                         int other_stage =   a_renames == renames1 ? 3 : 2;
1117
1118                         remove_file(o, 1, ren1_src,
1119                                     renamed_stage == 2 || !was_tracked(ren1_src));
1120
1121                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1122                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1123                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1124                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1125                         try_merge = 0;
1126
1127                         if (sha_eq(src_other.sha1, null_sha1)) {
1128                                 if (dir_in_way(ren1_dst, 0 /*check_wc*/)) {
1129                                         ren1->dst_entry->processed = 0;
1130                                         setup_rename_df_conflict_info(RENAME_DELETE,
1131                                                                       ren1->pair,
1132                                                                       NULL,
1133                                                                       branch1,
1134                                                                       branch2,
1135                                                                       ren1->dst_entry,
1136                                                                       NULL);
1137                                 } else {
1138                                         clean_merge = 0;
1139                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1140                                 }
1141                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1142                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1143                                 /* Added file on the other side
1144                                    identical to the file being
1145                                    renamed: clean merge */
1146                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1147                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1148                                 clean_merge = 0;
1149                                 try_merge = 1;
1150                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1151                                        "%s added in %s",
1152                                        ren1_src, ren1_dst, branch1,
1153                                        ren1_dst, branch2);
1154                                 if (o->call_depth) {
1155                                         struct merge_file_info mfi;
1156                                         struct diff_filespec one, a, b;
1157
1158                                         one.path = a.path = b.path =
1159                                                 (char *)ren1_dst;
1160                                         hashcpy(one.sha1, null_sha1);
1161                                         one.mode = 0;
1162                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1163                                         a.mode = ren1->pair->two->mode;
1164                                         hashcpy(b.sha1, dst_other.sha1);
1165                                         b.mode = dst_other.mode;
1166                                         mfi = merge_file(o, &one, &a, &b,
1167                                                          branch1,
1168                                                          branch2);
1169                                         output(o, 1, "Adding merged %s", ren1_dst);
1170                                         update_file(o, 0,
1171                                                     mfi.sha,
1172                                                     mfi.mode,
1173                                                     ren1_dst);
1174                                         try_merge = 0;
1175                                 } else {
1176                                         char *new_path = unique_path(o, ren1_dst, branch2);
1177                                         output(o, 1, "Adding as %s instead", new_path);
1178                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1179                                         free(new_path);
1180                                 }
1181                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1182                                 ren2 = item->util;
1183                                 clean_merge = 0;
1184                                 ren2->processed = 1;
1185                                 output(o, 1, "CONFLICT (rename/rename): "
1186                                        "Rename %s->%s in %s. "
1187                                        "Rename %s->%s in %s",
1188                                        ren1_src, ren1_dst, branch1,
1189                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1190                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1191                         } else
1192                                 try_merge = 1;
1193
1194                         if (try_merge) {
1195                                 struct diff_filespec *one, *a, *b;
1196                                 src_other.path = (char *)ren1_src;
1197
1198                                 one = ren1->pair->one;
1199                                 if (a_renames == renames1) {
1200                                         a = ren1->pair->two;
1201                                         b = &src_other;
1202                                 } else {
1203                                         b = ren1->pair->two;
1204                                         a = &src_other;
1205                                 }
1206                                 update_entry(ren1->dst_entry, one, a, b);
1207                                 ren1->dst_entry->involved_in_rename = 1;
1208                                 if (dir_in_way(ren1_dst, 0 /*check_wc*/)) {
1209                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1210                                                                       ren1->pair,
1211                                                                       NULL,
1212                                                                       branch1,
1213                                                                       NULL,
1214                                                                       ren1->dst_entry,
1215                                                                       NULL);
1216                                 }
1217                         }
1218                 }
1219         }
1220         string_list_clear(&a_by_dst, 0);
1221         string_list_clear(&b_by_dst, 0);
1222
1223         return clean_merge;
1224 }
1225
1226 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1227 {
1228         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1229 }
1230
1231 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1232 {
1233         void *buf;
1234         enum object_type type;
1235         unsigned long size;
1236         buf = read_sha1_file(sha1, &type, &size);
1237         if (!buf)
1238                 return error("cannot read object %s", sha1_to_hex(sha1));
1239         if (type != OBJ_BLOB) {
1240                 free(buf);
1241                 return error("object %s is not a blob", sha1_to_hex(sha1));
1242         }
1243         strbuf_attach(dst, buf, size, size + 1);
1244         return 0;
1245 }
1246
1247 static int blob_unchanged(const unsigned char *o_sha,
1248                           const unsigned char *a_sha,
1249                           int renormalize, const char *path)
1250 {
1251         struct strbuf o = STRBUF_INIT;
1252         struct strbuf a = STRBUF_INIT;
1253         int ret = 0; /* assume changed for safety */
1254
1255         if (sha_eq(o_sha, a_sha))
1256                 return 1;
1257         if (!renormalize)
1258                 return 0;
1259
1260         assert(o_sha && a_sha);
1261         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1262                 goto error_return;
1263         /*
1264          * Note: binary | is used so that both renormalizations are
1265          * performed.  Comparison can be skipped if both files are
1266          * unchanged since their sha1s have already been compared.
1267          */
1268         if (renormalize_buffer(path, o.buf, o.len, &o) |
1269             renormalize_buffer(path, a.buf, o.len, &a))
1270                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1271
1272 error_return:
1273         strbuf_release(&o);
1274         strbuf_release(&a);
1275         return ret;
1276 }
1277
1278 static void handle_delete_modify(struct merge_options *o,
1279                                  const char *path,
1280                                  const char *new_path,
1281                                  unsigned char *a_sha, int a_mode,
1282                                  unsigned char *b_sha, int b_mode)
1283 {
1284         if (!a_sha) {
1285                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1286                        "and modified in %s. Version %s of %s left in tree%s%s.",
1287                        path, o->branch1,
1288                        o->branch2, o->branch2, path,
1289                        path == new_path ? "" : " at ",
1290                        path == new_path ? "" : new_path);
1291                 update_file(o, 0, b_sha, b_mode, new_path);
1292         } else {
1293                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1294                        "and modified in %s. Version %s of %s left in tree%s%s.",
1295                        path, o->branch2,
1296                        o->branch1, o->branch1, path,
1297                        path == new_path ? "" : " at ",
1298                        path == new_path ? "" : new_path);
1299                 update_file(o, 0, a_sha, a_mode, new_path);
1300         }
1301 }
1302
1303 static int merge_content(struct merge_options *o,
1304                          unsigned involved_in_rename,
1305                          const char *path,
1306                          unsigned char *o_sha, int o_mode,
1307                          unsigned char *a_sha, int a_mode,
1308                          unsigned char *b_sha, int b_mode,
1309                          const char *df_rename_conflict_branch)
1310 {
1311         const char *reason = "content";
1312         struct merge_file_info mfi;
1313         struct diff_filespec one, a, b;
1314         unsigned df_conflict_remains = 0;
1315
1316         if (!o_sha) {
1317                 reason = "add/add";
1318                 o_sha = (unsigned char *)null_sha1;
1319         }
1320         one.path = a.path = b.path = (char *)path;
1321         hashcpy(one.sha1, o_sha);
1322         one.mode = o_mode;
1323         hashcpy(a.sha1, a_sha);
1324         a.mode = a_mode;
1325         hashcpy(b.sha1, b_sha);
1326         b.mode = b_mode;
1327
1328         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1329         if (df_rename_conflict_branch &&
1330             dir_in_way(path, !o->call_depth)) {
1331                 df_conflict_remains = 1;
1332         }
1333
1334         if (mfi.clean && !df_conflict_remains &&
1335             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1336                 output(o, 3, "Skipped %s (merged same as existing)", path);
1337         else
1338                 output(o, 2, "Auto-merging %s", path);
1339
1340         if (!mfi.clean) {
1341                 if (S_ISGITLINK(mfi.mode))
1342                         reason = "submodule";
1343                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1344                                 reason, path);
1345                 if (involved_in_rename)
1346                         update_stages(path, &one, &a, &b);
1347         }
1348
1349         if (df_conflict_remains) {
1350                 char *new_path;
1351                 update_file_flags(o, mfi.sha, mfi.mode, path,
1352                                   o->call_depth || mfi.clean, 0);
1353                 new_path = unique_path(o, path, df_rename_conflict_branch);
1354                 mfi.clean = 0;
1355                 output(o, 1, "Adding as %s instead", new_path);
1356                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1357                 free(new_path);
1358         } else {
1359                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1360         }
1361         return mfi.clean;
1362
1363 }
1364
1365 /* Per entry merge function */
1366 static int process_entry(struct merge_options *o,
1367                          const char *path, struct stage_data *entry)
1368 {
1369         /*
1370         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1371         print_index_entry("\tpath: ", entry);
1372         */
1373         int clean_merge = 1;
1374         int normalize = o->renormalize;
1375         unsigned o_mode = entry->stages[1].mode;
1376         unsigned a_mode = entry->stages[2].mode;
1377         unsigned b_mode = entry->stages[3].mode;
1378         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1379         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1380         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1381
1382         if (entry->rename_df_conflict_info)
1383                 return 1; /* Such cases are handled elsewhere. */
1384
1385         entry->processed = 1;
1386         if (o_sha && (!a_sha || !b_sha)) {
1387                 /* Case A: Deleted in one */
1388                 if ((!a_sha && !b_sha) ||
1389                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1390                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1391                         /* Deleted in both or deleted in one and
1392                          * unchanged in the other */
1393                         if (a_sha)
1394                                 output(o, 2, "Removing %s", path);
1395                         /* do not touch working file if it did not exist */
1396                         remove_file(o, 1, path, !a_sha);
1397                 } else if (dir_in_way(path, 0 /*check_wc*/)) {
1398                         entry->processed = 0;
1399                         return 1; /* Assume clean until processed */
1400                 } else {
1401                         /* Deleted in one and changed in the other */
1402                         clean_merge = 0;
1403                         handle_delete_modify(o, path, path,
1404                                              a_sha, a_mode, b_sha, b_mode);
1405                 }
1406
1407         } else if ((!o_sha && a_sha && !b_sha) ||
1408                    (!o_sha && !a_sha && b_sha)) {
1409                 /* Case B: Added in one. */
1410                 unsigned mode;
1411                 const unsigned char *sha;
1412
1413                 if (a_sha) {
1414                         mode = a_mode;
1415                         sha = a_sha;
1416                 } else {
1417                         mode = b_mode;
1418                         sha = b_sha;
1419                 }
1420                 if (dir_in_way(path, 0 /*check_wc*/)) {
1421                         /* Handle D->F conflicts after all subfiles */
1422                         entry->processed = 0;
1423                         return 1; /* Assume clean until processed */
1424                 } else {
1425                         output(o, 2, "Adding %s", path);
1426                         update_file(o, 1, sha, mode, path);
1427                 }
1428         } else if (a_sha && b_sha) {
1429                 /* Case C: Added in both (check for same permissions) and */
1430                 /* case D: Modified in both, but differently. */
1431                 clean_merge = merge_content(o, entry->involved_in_rename, path,
1432                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1433                                             NULL);
1434         } else if (!o_sha && !a_sha && !b_sha) {
1435                 /*
1436                  * this entry was deleted altogether. a_mode == 0 means
1437                  * we had that path and want to actively remove it.
1438                  */
1439                 remove_file(o, 1, path, !a_mode);
1440         } else
1441                 die("Fatal merge failure, shouldn't happen.");
1442
1443         return clean_merge;
1444 }
1445
1446 /*
1447  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1448  * cases we can cleanly resolve D/F conflicts, process_entry() can
1449  * clean out all the files below the directory for us.  All D/F
1450  * conflict cases must be handled here at the end to make sure any
1451  * directories that can be cleaned out, are.
1452  *
1453  * Some rename conflicts may also be handled here that don't necessarily
1454  * involve D/F conflicts, since the code to handle them is generic enough
1455  * to handle those rename conflicts with or without D/F conflicts also
1456  * being involved.
1457  */
1458 static int process_df_entry(struct merge_options *o,
1459                             const char *path, struct stage_data *entry)
1460 {
1461         int clean_merge = 1;
1462         unsigned o_mode = entry->stages[1].mode;
1463         unsigned a_mode = entry->stages[2].mode;
1464         unsigned b_mode = entry->stages[3].mode;
1465         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1466         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1467         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1468
1469         entry->processed = 1;
1470         if (entry->rename_df_conflict_info) {
1471                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1472                 char *src;
1473                 switch (conflict_info->rename_type) {
1474                 case RENAME_NORMAL:
1475                         clean_merge = merge_content(o, entry->involved_in_rename, path,
1476                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1477                                                     conflict_info->branch1);
1478                         break;
1479                 case RENAME_DELETE:
1480                         clean_merge = 0;
1481                         conflict_rename_delete(o, conflict_info->pair1,
1482                                                conflict_info->branch1,
1483                                                conflict_info->branch2);
1484                         break;
1485                 case RENAME_ONE_FILE_TO_TWO:
1486                         src = conflict_info->pair1->one->path;
1487                         clean_merge = 0;
1488                         output(o, 1, "CONFLICT (rename/rename): "
1489                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1490                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1491                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1492                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1493                                o->call_depth ? " (left unresolved)" : "");
1494                         if (o->call_depth) {
1495                                 remove_file_from_cache(src);
1496                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1497                                             conflict_info->pair1->one->mode, src);
1498                         }
1499                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1500                                                     conflict_info->branch1,
1501                                                     conflict_info->pair2,
1502                                                     conflict_info->branch2);
1503                         conflict_info->dst_entry2->processed = 1;
1504                         break;
1505                 default:
1506                         entry->processed = 0;
1507                         break;
1508                 }
1509         } else if (o_sha && (!a_sha || !b_sha)) {
1510                 /* Modify/delete; deleted side may have put a directory in the way */
1511                 char *renamed = NULL;
1512                 if (dir_in_way(path, !o->call_depth)) {
1513                         renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1514                 }
1515                 clean_merge = 0;
1516                 handle_delete_modify(o, path, renamed ? renamed : path,
1517                                      a_sha, a_mode, b_sha, b_mode);
1518                 free(renamed);
1519         } else if (!o_sha && !!a_sha != !!b_sha) {
1520                 /* directory -> (directory, file) or <nothing> -> (directory, file) */
1521                 const char *add_branch;
1522                 const char *other_branch;
1523                 unsigned mode;
1524                 const unsigned char *sha;
1525                 const char *conf;
1526
1527                 if (a_sha) {
1528                         add_branch = o->branch1;
1529                         other_branch = o->branch2;
1530                         mode = a_mode;
1531                         sha = a_sha;
1532                         conf = "file/directory";
1533                 } else {
1534                         add_branch = o->branch2;
1535                         other_branch = o->branch1;
1536                         mode = b_mode;
1537                         sha = b_sha;
1538                         conf = "directory/file";
1539                 }
1540                 if (dir_in_way(path, !o->call_depth)) {
1541                         char *new_path = unique_path(o, path, add_branch);
1542                         clean_merge = 0;
1543                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1544                                "Adding %s as %s",
1545                                conf, path, other_branch, path, new_path);
1546                         update_file(o, 0, sha, mode, new_path);
1547                         if (o->call_depth)
1548                                 remove_file_from_cache(path);
1549                         free(new_path);
1550                 } else {
1551                         output(o, 2, "Adding %s", path);
1552                         update_file(o, 1, sha, mode, path);
1553                 }
1554         } else {
1555                 entry->processed = 0;
1556                 return 1; /* not handled; assume clean until processed */
1557         }
1558
1559         return clean_merge;
1560 }
1561
1562 int merge_trees(struct merge_options *o,
1563                 struct tree *head,
1564                 struct tree *merge,
1565                 struct tree *common,
1566                 struct tree **result)
1567 {
1568         int code, clean;
1569
1570         if (o->subtree_shift) {
1571                 merge = shift_tree_object(head, merge, o->subtree_shift);
1572                 common = shift_tree_object(head, common, o->subtree_shift);
1573         }
1574
1575         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1576                 output(o, 0, "Already up-to-date!");
1577                 *result = head;
1578                 return 1;
1579         }
1580
1581         code = git_merge_trees(o->call_depth, common, head, merge);
1582
1583         if (code != 0) {
1584                 if (show(o, 4) || o->call_depth)
1585                         die("merging of trees %s and %s failed",
1586                             sha1_to_hex(head->object.sha1),
1587                             sha1_to_hex(merge->object.sha1));
1588                 else
1589                         exit(128);
1590         }
1591
1592         if (unmerged_cache()) {
1593                 struct string_list *entries, *re_head, *re_merge;
1594                 int i;
1595                 string_list_clear(&o->current_file_set, 1);
1596                 string_list_clear(&o->current_directory_set, 1);
1597                 get_files_dirs(o, head);
1598                 get_files_dirs(o, merge);
1599
1600                 entries = get_unmerged();
1601                 record_df_conflict_files(o, entries);
1602                 re_head  = get_renames(o, head, common, head, merge, entries);
1603                 re_merge = get_renames(o, merge, common, head, merge, entries);
1604                 clean = process_renames(o, re_head, re_merge);
1605                 for (i = 0; i < entries->nr; i++) {
1606                         const char *path = entries->items[i].string;
1607                         struct stage_data *e = entries->items[i].util;
1608                         if (!e->processed
1609                                 && !process_entry(o, path, e))
1610                                 clean = 0;
1611                 }
1612                 for (i = 0; i < entries->nr; i++) {
1613                         const char *path = entries->items[i].string;
1614                         struct stage_data *e = entries->items[i].util;
1615                         if (!e->processed
1616                                 && !process_df_entry(o, path, e))
1617                                 clean = 0;
1618                 }
1619                 for (i = 0; i < entries->nr; i++) {
1620                         struct stage_data *e = entries->items[i].util;
1621                         if (!e->processed)
1622                                 die("Unprocessed path??? %s",
1623                                     entries->items[i].string);
1624                 }
1625
1626                 string_list_clear(re_merge, 0);
1627                 string_list_clear(re_head, 0);
1628                 string_list_clear(entries, 1);
1629
1630         }
1631         else
1632                 clean = 1;
1633
1634         if (o->call_depth)
1635                 *result = write_tree_from_memory(o);
1636
1637         return clean;
1638 }
1639
1640 static struct commit_list *reverse_commit_list(struct commit_list *list)
1641 {
1642         struct commit_list *next = NULL, *current, *backup;
1643         for (current = list; current; current = backup) {
1644                 backup = current->next;
1645                 current->next = next;
1646                 next = current;
1647         }
1648         return next;
1649 }
1650
1651 /*
1652  * Merge the commits h1 and h2, return the resulting virtual
1653  * commit object and a flag indicating the cleanness of the merge.
1654  */
1655 int merge_recursive(struct merge_options *o,
1656                     struct commit *h1,
1657                     struct commit *h2,
1658                     struct commit_list *ca,
1659                     struct commit **result)
1660 {
1661         struct commit_list *iter;
1662         struct commit *merged_common_ancestors;
1663         struct tree *mrtree = mrtree;
1664         int clean;
1665
1666         if (show(o, 4)) {
1667                 output(o, 4, "Merging:");
1668                 output_commit_title(o, h1);
1669                 output_commit_title(o, h2);
1670         }
1671
1672         if (!ca) {
1673                 ca = get_merge_bases(h1, h2, 1);
1674                 ca = reverse_commit_list(ca);
1675         }
1676
1677         if (show(o, 5)) {
1678                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1679                 for (iter = ca; iter; iter = iter->next)
1680                         output_commit_title(o, iter->item);
1681         }
1682
1683         merged_common_ancestors = pop_commit(&ca);
1684         if (merged_common_ancestors == NULL) {
1685                 /* if there is no common ancestor, make an empty tree */
1686                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1687
1688                 tree->object.parsed = 1;
1689                 tree->object.type = OBJ_TREE;
1690                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1691                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1692         }
1693
1694         for (iter = ca; iter; iter = iter->next) {
1695                 const char *saved_b1, *saved_b2;
1696                 o->call_depth++;
1697                 /*
1698                  * When the merge fails, the result contains files
1699                  * with conflict markers. The cleanness flag is
1700                  * ignored, it was never actually used, as result of
1701                  * merge_trees has always overwritten it: the committed
1702                  * "conflicts" were already resolved.
1703                  */
1704                 discard_cache();
1705                 saved_b1 = o->branch1;
1706                 saved_b2 = o->branch2;
1707                 o->branch1 = "Temporary merge branch 1";
1708                 o->branch2 = "Temporary merge branch 2";
1709                 merge_recursive(o, merged_common_ancestors, iter->item,
1710                                 NULL, &merged_common_ancestors);
1711                 o->branch1 = saved_b1;
1712                 o->branch2 = saved_b2;
1713                 o->call_depth--;
1714
1715                 if (!merged_common_ancestors)
1716                         die("merge returned no commit");
1717         }
1718
1719         discard_cache();
1720         if (!o->call_depth)
1721                 read_cache();
1722
1723         o->ancestor = "merged common ancestors";
1724         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1725                             &mrtree);
1726
1727         if (o->call_depth) {
1728                 *result = make_virtual_commit(mrtree, "merged tree");
1729                 commit_list_insert(h1, &(*result)->parents);
1730                 commit_list_insert(h2, &(*result)->parents->next);
1731         }
1732         flush_output(o);
1733         if (show(o, 2))
1734                 diff_warn_rename_limit("merge.renamelimit",
1735                                        o->needed_rename_limit, 0);
1736         return clean;
1737 }
1738
1739 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1740 {
1741         struct object *object;
1742
1743         object = deref_tag(parse_object(sha1), name, strlen(name));
1744         if (!object)
1745                 return NULL;
1746         if (object->type == OBJ_TREE)
1747                 return make_virtual_commit((struct tree*)object, name);
1748         if (object->type != OBJ_COMMIT)
1749                 return NULL;
1750         if (parse_commit((struct commit *)object))
1751                 return NULL;
1752         return (struct commit *)object;
1753 }
1754
1755 int merge_recursive_generic(struct merge_options *o,
1756                             const unsigned char *head,
1757                             const unsigned char *merge,
1758                             int num_base_list,
1759                             const unsigned char **base_list,
1760                             struct commit **result)
1761 {
1762         int clean, index_fd;
1763         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1764         struct commit *head_commit = get_ref(head, o->branch1);
1765         struct commit *next_commit = get_ref(merge, o->branch2);
1766         struct commit_list *ca = NULL;
1767
1768         if (base_list) {
1769                 int i;
1770                 for (i = 0; i < num_base_list; ++i) {
1771                         struct commit *base;
1772                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1773                                 return error("Could not parse object '%s'",
1774                                         sha1_to_hex(base_list[i]));
1775                         commit_list_insert(base, &ca);
1776                 }
1777         }
1778
1779         index_fd = hold_locked_index(lock, 1);
1780         clean = merge_recursive(o, head_commit, next_commit, ca,
1781                         result);
1782         if (active_cache_changed &&
1783                         (write_cache(index_fd, active_cache, active_nr) ||
1784                          commit_locked_index(lock)))
1785                 return error("Unable to write index.");
1786
1787         return clean ? 0 : 1;
1788 }
1789
1790 static int merge_recursive_config(const char *var, const char *value, void *cb)
1791 {
1792         struct merge_options *o = cb;
1793         if (!strcmp(var, "merge.verbosity")) {
1794                 o->verbosity = git_config_int(var, value);
1795                 return 0;
1796         }
1797         if (!strcmp(var, "diff.renamelimit")) {
1798                 o->diff_rename_limit = git_config_int(var, value);
1799                 return 0;
1800         }
1801         if (!strcmp(var, "merge.renamelimit")) {
1802                 o->merge_rename_limit = git_config_int(var, value);
1803                 return 0;
1804         }
1805         return git_xmerge_config(var, value, cb);
1806 }
1807
1808 void init_merge_options(struct merge_options *o)
1809 {
1810         memset(o, 0, sizeof(struct merge_options));
1811         o->verbosity = 2;
1812         o->buffer_output = 1;
1813         o->diff_rename_limit = -1;
1814         o->merge_rename_limit = -1;
1815         o->renormalize = 0;
1816         git_config(merge_recursive_config, o);
1817         if (getenv("GIT_MERGE_VERBOSITY"))
1818                 o->verbosity =
1819                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1820         if (o->verbosity >= 5)
1821                 o->buffer_output = 0;
1822         strbuf_init(&o->obuf, 0);
1823         memset(&o->current_file_set, 0, sizeof(struct string_list));
1824         o->current_file_set.strdup_strings = 1;
1825         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1826         o->current_directory_set.strdup_strings = 1;
1827         memset(&o->df_conflict_file_set, 0, sizeof(struct string_list));
1828         o->df_conflict_file_set.strdup_strings = 1;
1829 }
1830
1831 int parse_merge_opt(struct merge_options *o, const char *s)
1832 {
1833         if (!s || !*s)
1834                 return -1;
1835         if (!strcmp(s, "ours"))
1836                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1837         else if (!strcmp(s, "theirs"))
1838                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1839         else if (!strcmp(s, "subtree"))
1840                 o->subtree_shift = "";
1841         else if (!prefixcmp(s, "subtree="))
1842                 o->subtree_shift = s + strlen("subtree=");
1843         else if (!strcmp(s, "patience"))
1844                 o->xdl_opts |= XDF_PATIENCE_DIFF;
1845         else if (!strcmp(s, "ignore-space-change"))
1846                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1847         else if (!strcmp(s, "ignore-all-space"))
1848                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
1849         else if (!strcmp(s, "ignore-space-at-eol"))
1850                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
1851         else if (!strcmp(s, "renormalize"))
1852                 o->renormalize = 1;
1853         else if (!strcmp(s, "no-renormalize"))
1854                 o->renormalize = 0;
1855         else if (!prefixcmp(s, "rename-threshold=")) {
1856                 const char *score = s + strlen("rename-threshold=");
1857                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
1858                         return -1;
1859         }
1860         else
1861                 return -1;
1862         return 0;
1863 }