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