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 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  42 {
  43         struct commit *commit = xcalloc(1, sizeof(struct commit));
  44         struct merge_remote_desc *desc = xmalloc(sizeof(*desc));
  45
  46         desc->name = comment;
  47         desc->obj = (struct object *)commit;
  48         commit->tree = tree;
  49         commit->util = desc;
  50         commit->object.parsed = 1;
  51         return commit;
  52 }
  53
  54 /*
  55  * Since we use get_tree_entry(), which does not put the read object into
  56  * the object pool, we cannot rely on a == b.
  57  */
  58 static int sha_eq(const unsigned char *a, const unsigned char *b)
  59 {
  60         if (!a && !b)
  61                 return 2;
  62         return a && b && hashcmp(a, b) == 0;
  63 }
  64
  65 enum rename_type {
  66         RENAME_NORMAL = 0,
  67         RENAME_DELETE,
  68         RENAME_ONE_FILE_TO_ONE,
  69         RENAME_ONE_FILE_TO_TWO,
  70         RENAME_TWO_FILES_TO_ONE
  71 };
  72
  73 struct rename_conflict_info {
  74         enum rename_type rename_type;
  75         struct diff_filepair *pair1;
  76         struct diff_filepair *pair2;
  77         const char *branch1;
  78         const char *branch2;
  79         struct stage_data *dst_entry1;
  80         struct stage_data *dst_entry2;
  81         struct diff_filespec ren1_other;
  82         struct diff_filespec ren2_other;
  83 };
  84
  85 /*
  86  * Since we want to write the index eventually, we cannot reuse the index
  87  * for these (temporary) data.
  88  */
  89 struct stage_data {
  90         struct {
  91                 unsigned mode;
  92                 unsigned char sha[20];
  93         } stages[4];
  94         struct rename_conflict_info *rename_conflict_info;
  95         unsigned processed:1;
  96 };
  97
  98 static inline void setup_rename_conflict_info(enum rename_type rename_type,
  99                                               struct diff_filepair *pair1,
 100                                               struct diff_filepair *pair2,
 101                                               const char *branch1,
 102                                               const char *branch2,
 103                                               struct stage_data *dst_entry1,
 104                                               struct stage_data *dst_entry2,
 105                                               struct merge_options *o,
 106                                               struct stage_data *src_entry1,
 107                                               struct stage_data *src_entry2)
 108 {
 109         struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
 110         ci->rename_type = rename_type;
 111         ci->pair1 = pair1;
 112         ci->branch1 = branch1;
 113         ci->branch2 = branch2;
 114
 115         ci->dst_entry1 = dst_entry1;
 116         dst_entry1->rename_conflict_info = ci;
 117         dst_entry1->processed = 0;
 118
 119         assert(!pair2 == !dst_entry2);
 120         if (dst_entry2) {
 121                 ci->dst_entry2 = dst_entry2;
 122                 ci->pair2 = pair2;
 123                 dst_entry2->rename_conflict_info = ci;
 124         }
 125
 126         if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 127                 /*
 128                  * For each rename, there could have been
 129                  * modifications on the side of history where that
 130                  * file was not renamed.
 131                  */
 132                 int ostage1 = o->branch1 == branch1 ? 3 : 2;
 133                 int ostage2 = ostage1 ^ 1;
 134
 135                 ci->ren1_other.path = pair1->one->path;
 136                 hashcpy(ci->ren1_other.sha1, src_entry1->stages[ostage1].sha);
 137                 ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 138
 139                 ci->ren2_other.path = pair2->one->path;
 140                 hashcpy(ci->ren2_other.sha1, src_entry2->stages[ostage2].sha);
 141                 ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 142         }
 143 }
 144
 145 static int show(struct merge_options *o, int v)
 146 {
 147         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 148 }
 149
 150 static void flush_output(struct merge_options *o)
 151 {
 152         if (o->obuf.len) {
 153                 fputs(o->obuf.buf, stdout);
 154                 strbuf_reset(&o->obuf);
 155         }
 156 }
 157
 158 __attribute__((format (printf, 3, 4)))
 159 static void output(struct merge_options *o, int v, const char *fmt, ...)
 160 {
 161         va_list ap;
 162
 163         if (!show(o, v))
 164                 return;
 165
 166         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 167         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 168         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 169
 170         va_start(ap, fmt);
 171         strbuf_vaddf(&o->obuf, fmt, ap);
 172         va_end(ap);
 173
 174         strbuf_add(&o->obuf, "\n", 1);
 175         if (!o->buffer_output)
 176                 flush_output(o);
 177 }
 178
 179 static void output_commit_title(struct merge_options *o, struct commit *commit)
 180 {
 181         int i;
 182         flush_output(o);
 183         for (i = o->call_depth; i--;)
 184                 fputs("  ", stdout);
 185         if (commit->util)
 186                 printf("virtual %s\n", merge_remote_util(commit)->name);
 187         else {
 188                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 189                 if (parse_commit(commit) != 0)
 190                         printf(_("(bad commit)\n"));
 191                 else {
 192                         const char *title;
 193                         int len = find_commit_subject(commit->buffer, &title);
 194                         if (len)
 195                                 printf("%.*s\n", len, title);
 196                 }
 197         }
 198 }
 199
 200 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 201                 const char *path, int stage, int refresh, int options)
 202 {
 203         struct cache_entry *ce;
 204         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage,
 205                               (refresh ? CE_MATCH_REFRESH : 0 ));
 206         if (!ce)
 207                 return error(_("addinfo_cache failed for path '%s'"), path);
 208         return add_cache_entry(ce, options);
 209 }
 210
 211 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 212 {
 213         parse_tree(tree);
 214         init_tree_desc(desc, tree->buffer, tree->size);
 215 }
 216
 217 static int git_merge_trees(int index_only,
 218                            struct tree *common,
 219                            struct tree *head,
 220                            struct tree *merge)
 221 {
 222         int rc;
 223         struct tree_desc t[3];
 224         struct unpack_trees_options opts;
 225
 226         memset(&opts, 0, sizeof(opts));
 227         if (index_only)
 228                 opts.index_only = 1;
 229         else
 230                 opts.update = 1;
 231         opts.merge = 1;
 232         opts.head_idx = 2;
 233         opts.fn = threeway_merge;
 234         opts.src_index = &the_index;
 235         opts.dst_index = &the_index;
 236         setup_unpack_trees_porcelain(&opts, "merge");
 237
 238         init_tree_desc_from_tree(t+0, common);
 239         init_tree_desc_from_tree(t+1, head);
 240         init_tree_desc_from_tree(t+2, merge);
 241
 242         rc = unpack_trees(3, t, &opts);
 243         cache_tree_free(&active_cache_tree);
 244         return rc;
 245 }
 246
 247 struct tree *write_tree_from_memory(struct merge_options *o)
 248 {
 249         struct tree *result = NULL;
 250
 251         if (unmerged_cache()) {
 252                 int i;
 253                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 254                 for (i = 0; i < active_nr; i++) {
 255                         const struct cache_entry *ce = active_cache[i];
 256                         if (ce_stage(ce))
 257                                 fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 258                                         (int)ce_namelen(ce), ce->name);
 259                 }
 260                 die("Bug in merge-recursive.c");
 261         }
 262
 263         if (!active_cache_tree)
 264                 active_cache_tree = cache_tree();
 265
 266         if (!cache_tree_fully_valid(active_cache_tree) &&
 267             cache_tree_update(active_cache_tree,
 268                               (const struct cache_entry * const *)active_cache,
 269                               active_nr, 0) < 0)
 270                 die(_("error building trees"));
 271
 272         result = lookup_tree(active_cache_tree->sha1);
 273
 274         return result;
 275 }
 276
 277 static int save_files_dirs(const unsigned char *sha1,
 278                 const char *base, int baselen, const char *path,
 279                 unsigned int mode, int stage, void *context)
 280 {
 281         int len = strlen(path);
 282         char *newpath = xmalloc(baselen + len + 1);
 283         struct merge_options *o = context;
 284
 285         memcpy(newpath, base, baselen);
 286         memcpy(newpath + baselen, path, len);
 287         newpath[baselen + len] = '\0';
 288
 289         if (S_ISDIR(mode))
 290                 string_list_insert(&o->current_directory_set, newpath);
 291         else
 292                 string_list_insert(&o->current_file_set, newpath);
 293         free(newpath);
 294
 295         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 296 }
 297
 298 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 299 {
 300         int n;
 301         struct pathspec match_all;
 302         init_pathspec(&match_all, NULL);
 303         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
 304                 return 0;
 305         n = o->current_file_set.nr + o->current_directory_set.nr;
 306         return n;
 307 }
 308
 309 /*
 310  * Returns an index_entry instance which doesn't have to correspond to
 311  * a real cache entry in Git's index.
 312  */
 313 static struct stage_data *insert_stage_data(const char *path,
 314                 struct tree *o, struct tree *a, struct tree *b,
 315                 struct string_list *entries)
 316 {
 317         struct string_list_item *item;
 318         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 319         get_tree_entry(o->object.sha1, path,
 320                         e->stages[1].sha, &e->stages[1].mode);
 321         get_tree_entry(a->object.sha1, path,
 322                         e->stages[2].sha, &e->stages[2].mode);
 323         get_tree_entry(b->object.sha1, path,
 324                         e->stages[3].sha, &e->stages[3].mode);
 325         item = string_list_insert(entries, path);
 326         item->util = e;
 327         return e;
 328 }
 329
 330 /*
 331  * Create a dictionary mapping file names to stage_data objects. The
 332  * dictionary contains one entry for every path with a non-zero stage entry.
 333  */
 334 static struct string_list *get_unmerged(void)
 335 {
 336         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 337         int i;
 338
 339         unmerged->strdup_strings = 1;
 340
 341         for (i = 0; i < active_nr; i++) {
 342                 struct string_list_item *item;
 343                 struct stage_data *e;
 344                 const struct cache_entry *ce = active_cache[i];
 345                 if (!ce_stage(ce))
 346                         continue;
 347
 348                 item = string_list_lookup(unmerged, ce->name);
 349                 if (!item) {
 350                         item = string_list_insert(unmerged, ce->name);
 351                         item->util = xcalloc(1, sizeof(struct stage_data));
 352                 }
 353                 e = item->util;
 354                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 355                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 356         }
 357
 358         return unmerged;
 359 }
 360
 361 static int string_list_df_name_compare(const void *a, const void *b)
 362 {
 363         const struct string_list_item *one = a;
 364         const struct string_list_item *two = b;
 365         int onelen = strlen(one->string);
 366         int twolen = strlen(two->string);
 367         /*
 368          * Here we only care that entries for D/F conflicts are
 369          * adjacent, in particular with the file of the D/F conflict
 370          * appearing before files below the corresponding directory.
 371          * The order of the rest of the list is irrelevant for us.
 372          *
 373          * To achieve this, we sort with df_name_compare and provide
 374          * the mode S_IFDIR so that D/F conflicts will sort correctly.
 375          * We use the mode S_IFDIR for everything else for simplicity,
 376          * since in other cases any changes in their order due to
 377          * sorting cause no problems for us.
 378          */
 379         int cmp = df_name_compare(one->string, onelen, S_IFDIR,
 380                                   two->string, twolen, S_IFDIR);
 381         /*
 382          * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 383          * that 'foo' comes before 'foo/bar'.
 384          */
 385         if (cmp)
 386                 return cmp;
 387         return onelen - twolen;
 388 }
 389
 390 static void record_df_conflict_files(struct merge_options *o,
 391                                      struct string_list *entries)
 392 {
 393         /* If there is a D/F conflict and the file for such a conflict
 394          * currently exist in the working tree, we want to allow it to be
 395          * removed to make room for the corresponding directory if needed.
 396          * The files underneath the directories of such D/F conflicts will
 397          * be processed before the corresponding file involved in the D/F
 398          * conflict.  If the D/F directory ends up being removed by the
 399          * merge, then we won't have to touch the D/F file.  If the D/F
 400          * directory needs to be written to the working copy, then the D/F
 401          * file will simply be removed (in make_room_for_path()) to make
 402          * room for the necessary paths.  Note that if both the directory
 403          * and the file need to be present, then the D/F file will be
 404          * reinstated with a new unique name at the time it is processed.
 405          */
 406         struct string_list df_sorted_entries;
 407         const char *last_file = NULL;
 408         int last_len = 0;
 409         int i;
 410
 411         /*
 412          * If we're merging merge-bases, we don't want to bother with
 413          * any working directory changes.
 414          */
 415         if (o->call_depth)
 416                 return;
 417
 418         /* Ensure D/F conflicts are adjacent in the entries list. */
 419         memset(&df_sorted_entries, 0, sizeof(struct string_list));
 420         for (i = 0; i < entries->nr; i++) {
 421                 struct string_list_item *next = &entries->items[i];
 422                 string_list_append(&df_sorted_entries, next->string)->util =
 423                                    next->util;
 424         }
 425         qsort(df_sorted_entries.items, entries->nr, sizeof(*entries->items),
 426               string_list_df_name_compare);
 427
 428         string_list_clear(&o->df_conflict_file_set, 1);
 429         for (i = 0; i < df_sorted_entries.nr; i++) {
 430                 const char *path = df_sorted_entries.items[i].string;
 431                 int len = strlen(path);
 432                 struct stage_data *e = df_sorted_entries.items[i].util;
 433
 434                 /*
 435                  * Check if last_file & path correspond to a D/F conflict;
 436                  * i.e. whether path is last_file+'/'+<something>.
 437                  * If so, record that it's okay to remove last_file to make
 438                  * room for path and friends if needed.
 439                  */
 440                 if (last_file &&
 441                     len > last_len &&
 442                     memcmp(path, last_file, last_len) == 0 &&
 443                     path[last_len] == '/') {
 444                         string_list_insert(&o->df_conflict_file_set, last_file);
 445                 }
 446
 447                 /*
 448                  * Determine whether path could exist as a file in the
 449                  * working directory as a possible D/F conflict.  This
 450                  * will only occur when it exists in stage 2 as a
 451                  * file.
 452                  */
 453                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 454                         last_file = path;
 455                         last_len = len;
 456                 } else {
 457                         last_file = NULL;
 458                 }
 459         }
 460         string_list_clear(&df_sorted_entries, 0);
 461 }
 462
 463 struct rename {
 464         struct diff_filepair *pair;
 465         struct stage_data *src_entry;
 466         struct stage_data *dst_entry;
 467         unsigned processed:1;
 468 };
 469
 470 /*
 471  * Get information of all renames which occurred between 'o_tree' and
 472  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 473  * 'b_tree') to be able to associate the correct cache entries with
 474  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 475  */
 476 static struct string_list *get_renames(struct merge_options *o,
 477                                        struct tree *tree,
 478                                        struct tree *o_tree,
 479                                        struct tree *a_tree,
 480                                        struct tree *b_tree,
 481                                        struct string_list *entries)
 482 {
 483         int i;
 484         struct string_list *renames;
 485         struct diff_options opts;
 486
 487         renames = xcalloc(1, sizeof(struct string_list));
 488         diff_setup(&opts);
 489         DIFF_OPT_SET(&opts, RECURSIVE);
 490         DIFF_OPT_CLR(&opts, RENAME_EMPTY);
 491         opts.detect_rename = DIFF_DETECT_RENAME;
 492         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 493                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 494                             1000;
 495         opts.rename_score = o->rename_score;
 496         opts.show_rename_progress = o->show_rename_progress;
 497         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 498         diff_setup_done(&opts);
 499         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 500         diffcore_std(&opts);
 501         if (opts.needed_rename_limit > o->needed_rename_limit)
 502                 o->needed_rename_limit = opts.needed_rename_limit;
 503         for (i = 0; i < diff_queued_diff.nr; ++i) {
 504                 struct string_list_item *item;
 505                 struct rename *re;
 506                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 507                 if (pair->status != 'R') {
 508                         diff_free_filepair(pair);
 509                         continue;
 510                 }
 511                 re = xmalloc(sizeof(*re));
 512                 re->processed = 0;
 513                 re->pair = pair;
 514                 item = string_list_lookup(entries, re->pair->one->path);
 515                 if (!item)
 516                         re->src_entry = insert_stage_data(re->pair->one->path,
 517                                         o_tree, a_tree, b_tree, entries);
 518                 else
 519                         re->src_entry = item->util;
 520
 521                 item = string_list_lookup(entries, re->pair->two->path);
 522                 if (!item)
 523                         re->dst_entry = insert_stage_data(re->pair->two->path,
 524                                         o_tree, a_tree, b_tree, entries);
 525                 else
 526                         re->dst_entry = item->util;
 527                 item = string_list_insert(renames, pair->one->path);
 528                 item->util = re;
 529         }
 530         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 531         diff_queued_diff.nr = 0;
 532         diff_flush(&opts);
 533         return renames;
 534 }
 535
 536 static int update_stages(const char *path, const struct diff_filespec *o,
 537                          const struct diff_filespec *a,
 538                          const struct diff_filespec *b)
 539 {
 540
 541         /*
 542          * NOTE: It is usually a bad idea to call update_stages on a path
 543          * before calling update_file on that same path, since it can
 544          * sometimes lead to spurious "refusing to lose untracked file..."
 545          * messages from update_file (via make_room_for path via
 546          * would_lose_untracked).  Instead, reverse the order of the calls
 547          * (executing update_file first and then update_stages).
 548          */
 549         int clear = 1;
 550         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 551         if (clear)
 552                 if (remove_file_from_cache(path))
 553                         return -1;
 554         if (o)
 555                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 556                         return -1;
 557         if (a)
 558                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 559                         return -1;
 560         if (b)
 561                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 562                         return -1;
 563         return 0;
 564 }
 565
 566 static void update_entry(struct stage_data *entry,
 567                          struct diff_filespec *o,
 568                          struct diff_filespec *a,
 569                          struct diff_filespec *b)
 570 {
 571         entry->processed = 0;
 572         entry->stages[1].mode = o->mode;
 573         entry->stages[2].mode = a->mode;
 574         entry->stages[3].mode = b->mode;
 575         hashcpy(entry->stages[1].sha, o->sha1);
 576         hashcpy(entry->stages[2].sha, a->sha1);
 577         hashcpy(entry->stages[3].sha, b->sha1);
 578 }
 579
 580 static int remove_file(struct merge_options *o, int clean,
 581                        const char *path, int no_wd)
 582 {
 583         int update_cache = o->call_depth || clean;
 584         int update_working_directory = !o->call_depth && !no_wd;
 585
 586         if (update_cache) {
 587                 if (remove_file_from_cache(path))
 588                         return -1;
 589         }
 590         if (update_working_directory) {
 591                 if (remove_path(path))
 592                         return -1;
 593         }
 594         return 0;
 595 }
 596
 597 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 598 {
 599         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 600         int suffix = 0;
 601         struct stat st;
 602         char *p = newpath + strlen(path);
 603         strcpy(newpath, path);
 604         *(p++) = '~';
 605         strcpy(p, branch);
 606         for (; *p; ++p)
 607                 if ('/' == *p)
 608                         *p = '_';
 609         while (string_list_has_string(&o->current_file_set, newpath) ||
 610                string_list_has_string(&o->current_directory_set, newpath) ||
 611                lstat(newpath, &st) == 0)
 612                 sprintf(p, "_%d", suffix++);
 613
 614         string_list_insert(&o->current_file_set, newpath);
 615         return newpath;
 616 }
 617
 618 static int dir_in_way(const char *path, int check_working_copy)
 619 {
 620         int pos, pathlen = strlen(path);
 621         char *dirpath = xmalloc(pathlen + 2);
 622         struct stat st;
 623
 624         strcpy(dirpath, path);
 625         dirpath[pathlen] = '/';
 626         dirpath[pathlen+1] = '\0';
 627
 628         pos = cache_name_pos(dirpath, pathlen+1);
 629
 630         if (pos < 0)
 631                 pos = -1 - pos;
 632         if (pos < active_nr &&
 633             !strncmp(dirpath, active_cache[pos]->name, pathlen+1)) {
 634                 free(dirpath);
 635                 return 1;
 636         }
 637
 638         free(dirpath);
 639         return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode);
 640 }
 641
 642 static int was_tracked(const char *path)
 643 {
 644         int pos = cache_name_pos(path, strlen(path));
 645
 646         if (pos < 0)
 647                 pos = -1 - pos;
 648         while (pos < active_nr &&
 649                !strcmp(path, active_cache[pos]->name)) {
 650                 /*
 651                  * If stage #0, it is definitely tracked.
 652                  * If it has stage #2 then it was tracked
 653                  * before this merge started.  All other
 654                  * cases the path was not tracked.
 655                  */
 656                 switch (ce_stage(active_cache[pos])) {
 657                 case 0:
 658                 case 2:
 659                         return 1;
 660                 }
 661                 pos++;
 662         }
 663         return 0;
 664 }
 665
 666 static int would_lose_untracked(const char *path)
 667 {
 668         return !was_tracked(path) && file_exists(path);
 669 }
 670
 671 static int make_room_for_path(struct merge_options *o, const char *path)
 672 {
 673         int status, i;
 674         const char *msg = _("failed to create path '%s'%s");
 675
 676         /* Unlink any D/F conflict files that are in the way */
 677         for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 678                 const char *df_path = o->df_conflict_file_set.items[i].string;
 679                 size_t pathlen = strlen(path);
 680                 size_t df_pathlen = strlen(df_path);
 681                 if (df_pathlen < pathlen &&
 682                     path[df_pathlen] == '/' &&
 683                     strncmp(path, df_path, df_pathlen) == 0) {
 684                         output(o, 3,
 685                                _("Removing %s to make room for subdirectory\n"),
 686                                df_path);
 687                         unlink(df_path);
 688                         unsorted_string_list_delete_item(&o->df_conflict_file_set,
 689                                                          i, 0);
 690                         break;
 691                 }
 692         }
 693
 694         /* Make sure leading directories are created */
 695         status = safe_create_leading_directories_const(path);
 696         if (status) {
 697                 if (status == -3) {
 698                         /* something else exists */
 699                         error(msg, path, _(": perhaps a D/F conflict?"));
 700                         return -1;
 701                 }
 702                 die(msg, path, "");
 703         }
 704
 705         /*
 706          * Do not unlink a file in the work tree if we are not
 707          * tracking it.
 708          */
 709         if (would_lose_untracked(path))
 710                 return error(_("refusing to lose untracked file at '%s'"),
 711                              path);
 712
 713         /* Successful unlink is good.. */
 714         if (!unlink(path))
 715                 return 0;
 716         /* .. and so is no existing file */
 717         if (errno == ENOENT)
 718                 return 0;
 719         /* .. but not some other error (who really cares what?) */
 720         return error(msg, path, _(": perhaps a D/F conflict?"));
 721 }
 722
 723 static void update_file_flags(struct merge_options *o,
 724                               const unsigned char *sha,
 725                               unsigned mode,
 726                               const char *path,
 727                               int update_cache,
 728                               int update_wd)
 729 {
 730         if (o->call_depth)
 731                 update_wd = 0;
 732
 733         if (update_wd) {
 734                 enum object_type type;
 735                 void *buf;
 736                 unsigned long size;
 737
 738                 if (S_ISGITLINK(mode)) {
 739                         /*
 740                          * We may later decide to recursively descend into
 741                          * the submodule directory and update its index
 742                          * and/or work tree, but we do not do that now.
 743                          */
 744                         update_wd = 0;
 745                         goto update_index;
 746                 }
 747
 748                 buf = read_sha1_file(sha, &type, &size);
 749                 if (!buf)
 750                         die(_("cannot read object %s '%s'"), sha1_to_hex(sha), path);
 751                 if (type != OBJ_BLOB)
 752                         die(_("blob expected for %s '%s'"), sha1_to_hex(sha), path);
 753                 if (S_ISREG(mode)) {
 754                         struct strbuf strbuf = STRBUF_INIT;
 755                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 756                                 free(buf);
 757                                 size = strbuf.len;
 758                                 buf = strbuf_detach(&strbuf, NULL);
 759                         }
 760                 }
 761
 762                 if (make_room_for_path(o, path) < 0) {
 763                         update_wd = 0;
 764                         free(buf);
 765                         goto update_index;
 766                 }
 767                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 768                         int fd;
 769                         if (mode & 0100)
 770                                 mode = 0777;
 771                         else
 772                                 mode = 0666;
 773                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 774                         if (fd < 0)
 775                                 die_errno(_("failed to open '%s'"), path);
 776                         write_in_full(fd, buf, size);
 777                         close(fd);
 778                 } else if (S_ISLNK(mode)) {
 779                         char *lnk = xmemdupz(buf, size);
 780                         safe_create_leading_directories_const(path);
 781                         unlink(path);
 782                         if (symlink(lnk, path))
 783                                 die_errno(_("failed to symlink '%s'"), path);
 784                         free(lnk);
 785                 } else
 786                         die(_("do not know what to do with %06o %s '%s'"),
 787                             mode, sha1_to_hex(sha), path);
 788                 free(buf);
 789         }
 790  update_index:
 791         if (update_cache)
 792                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 793 }
 794
 795 static void update_file(struct merge_options *o,
 796                         int clean,
 797                         const unsigned char *sha,
 798                         unsigned mode,
 799                         const char *path)
 800 {
 801         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 802 }
 803
 804 /* Low level file merging, update and removal */
 805
 806 struct merge_file_info {
 807         unsigned char sha[20];
 808         unsigned mode;
 809         unsigned clean:1,
 810                  merge:1;
 811 };
 812
 813 static int merge_3way(struct merge_options *o,
 814                       mmbuffer_t *result_buf,
 815                       const struct diff_filespec *one,
 816                       const struct diff_filespec *a,
 817                       const struct diff_filespec *b,
 818                       const char *branch1,
 819                       const char *branch2)
 820 {
 821         mmfile_t orig, src1, src2;
 822         struct ll_merge_options ll_opts = {0};
 823         char *base_name, *name1, *name2;
 824         int merge_status;
 825
 826         ll_opts.renormalize = o->renormalize;
 827         ll_opts.xdl_opts = o->xdl_opts;
 828
 829         if (o->call_depth) {
 830                 ll_opts.virtual_ancestor = 1;
 831                 ll_opts.variant = 0;
 832         } else {
 833                 switch (o->recursive_variant) {
 834                 case MERGE_RECURSIVE_OURS:
 835                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 836                         break;
 837                 case MERGE_RECURSIVE_THEIRS:
 838                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 839                         break;
 840                 default:
 841                         ll_opts.variant = 0;
 842                         break;
 843                 }
 844         }
 845
 846         if (strcmp(a->path, b->path) ||
 847             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 848                 base_name = o->ancestor == NULL ? NULL :
 849                         mkpathdup("%s:%s", o->ancestor, one->path);
 850                 name1 = mkpathdup("%s:%s", branch1, a->path);
 851                 name2 = mkpathdup("%s:%s", branch2, b->path);
 852         } else {
 853                 base_name = o->ancestor == NULL ? NULL :
 854                         mkpathdup("%s", o->ancestor);
 855                 name1 = mkpathdup("%s", branch1);
 856                 name2 = mkpathdup("%s", branch2);
 857         }
 858
 859         read_mmblob(&orig, one->sha1);
 860         read_mmblob(&src1, a->sha1);
 861         read_mmblob(&src2, b->sha1);
 862
 863         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 864                                 &src1, name1, &src2, name2, &ll_opts);
 865
 866         free(base_name);
 867         free(name1);
 868         free(name2);
 869         free(orig.ptr);
 870         free(src1.ptr);
 871         free(src2.ptr);
 872         return merge_status;
 873 }
 874
 875 static struct merge_file_info merge_file_1(struct merge_options *o,
 876                                            const struct diff_filespec *one,
 877                                            const struct diff_filespec *a,
 878                                            const struct diff_filespec *b,
 879                                            const char *branch1,
 880                                            const char *branch2)
 881 {
 882         struct merge_file_info result;
 883         result.merge = 0;
 884         result.clean = 1;
 885
 886         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 887                 result.clean = 0;
 888                 if (S_ISREG(a->mode)) {
 889                         result.mode = a->mode;
 890                         hashcpy(result.sha, a->sha1);
 891                 } else {
 892                         result.mode = b->mode;
 893                         hashcpy(result.sha, b->sha1);
 894                 }
 895         } else {
 896                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 897                         result.merge = 1;
 898
 899                 /*
 900                  * Merge modes
 901                  */
 902                 if (a->mode == b->mode || a->mode == one->mode)
 903                         result.mode = b->mode;
 904                 else {
 905                         result.mode = a->mode;
 906                         if (b->mode != one->mode) {
 907                                 result.clean = 0;
 908                                 result.merge = 1;
 909                         }
 910                 }
 911
 912                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 913                         hashcpy(result.sha, b->sha1);
 914                 else if (sha_eq(b->sha1, one->sha1))
 915                         hashcpy(result.sha, a->sha1);
 916                 else if (S_ISREG(a->mode)) {
 917                         mmbuffer_t result_buf;
 918                         int merge_status;
 919
 920                         merge_status = merge_3way(o, &result_buf, one, a, b,
 921                                                   branch1, branch2);
 922
 923                         if ((merge_status < 0) || !result_buf.ptr)
 924                                 die(_("Failed to execute internal merge"));
 925
 926                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 927                                             blob_type, result.sha))
 928                                 die(_("Unable to add %s to database"),
 929                                     a->path);
 930
 931                         free(result_buf.ptr);
 932                         result.clean = (merge_status == 0);
 933                 } else if (S_ISGITLINK(a->mode)) {
 934                         result.clean = merge_submodule(result.sha,
 935                                                        one->path, one->sha1,
 936                                                        a->sha1, b->sha1,
 937                                                        !o->call_depth);
 938                 } else if (S_ISLNK(a->mode)) {
 939                         hashcpy(result.sha, a->sha1);
 940
 941                         if (!sha_eq(a->sha1, b->sha1))
 942                                 result.clean = 0;
 943                 } else {
 944                         die(_("unsupported object type in the tree"));
 945                 }
 946         }
 947
 948         return result;
 949 }
 950
 951 static struct merge_file_info
 952 merge_file_special_markers(struct merge_options *o,
 953                            const struct diff_filespec *one,
 954                            const struct diff_filespec *a,
 955                            const struct diff_filespec *b,
 956                            const char *branch1,
 957                            const char *filename1,
 958                            const char *branch2,
 959                            const char *filename2)
 960 {
 961         char *side1 = NULL;
 962         char *side2 = NULL;
 963         struct merge_file_info mfi;
 964
 965         if (filename1) {
 966                 side1 = xmalloc(strlen(branch1) + strlen(filename1) + 2);
 967                 sprintf(side1, "%s:%s", branch1, filename1);
 968         }
 969         if (filename2) {
 970                 side2 = xmalloc(strlen(branch2) + strlen(filename2) + 2);
 971                 sprintf(side2, "%s:%s", branch2, filename2);
 972         }
 973
 974         mfi = merge_file_1(o, one, a, b,
 975                            side1 ? side1 : branch1, side2 ? side2 : branch2);
 976         free(side1);
 977         free(side2);
 978         return mfi;
 979 }
 980
 981 static struct merge_file_info merge_file_one(struct merge_options *o,
 982                                          const char *path,
 983                                          const unsigned char *o_sha, int o_mode,
 984                                          const unsigned char *a_sha, int a_mode,
 985                                          const unsigned char *b_sha, int b_mode,
 986                                          const char *branch1,
 987                                          const char *branch2)
 988 {
 989         struct diff_filespec one, a, b;
 990
 991         one.path = a.path = b.path = (char *)path;
 992         hashcpy(one.sha1, o_sha);
 993         one.mode = o_mode;
 994         hashcpy(a.sha1, a_sha);
 995         a.mode = a_mode;
 996         hashcpy(b.sha1, b_sha);
 997         b.mode = b_mode;
 998         return merge_file_1(o, &one, &a, &b, branch1, branch2);
 999 }
1000
1001 static void handle_change_delete(struct merge_options *o,
1002                                  const char *path,
1003                                  const unsigned char *o_sha, int o_mode,
1004                                  const unsigned char *a_sha, int a_mode,
1005                                  const unsigned char *b_sha, int b_mode,
1006                                  const char *change, const char *change_past)
1007 {
1008         char *renamed = NULL;
1009         if (dir_in_way(path, !o->call_depth)) {
1010                 renamed = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1011         }
1012
1013         if (o->call_depth) {
1014                 /*
1015                  * We cannot arbitrarily accept either a_sha or b_sha as
1016                  * correct; since there is no true "middle point" between
1017                  * them, simply reuse the base version for virtual merge base.
1018                  */
1019                 remove_file_from_cache(path);
1020                 update_file(o, 0, o_sha, o_mode, renamed ? renamed : path);
1021         } else if (!a_sha) {
1022                 if (!renamed) {
1023                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1024                                "and %s in %s. Version %s of %s left in tree."),
1025                                change, path, o->branch1, change_past,
1026                                o->branch2, o->branch2, path);
1027                         update_file(o, 0, b_sha, b_mode, path);
1028                 } else {
1029                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1030                                "and %s in %s. Version %s of %s left in tree at %s."),
1031                                change, path, o->branch1, change_past,
1032                                o->branch2, o->branch2, path, renamed);
1033                         update_file(o, 0, b_sha, b_mode, renamed);
1034                 }
1035         } else {
1036                 if (!renamed) {
1037                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1038                                "and %s in %s. Version %s of %s left in tree."),
1039                                change, path, o->branch2, change_past,
1040                                o->branch1, o->branch1, path);
1041                 } else {
1042                         output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1043                                "and %s in %s. Version %s of %s left in tree at %s."),
1044                                change, path, o->branch2, change_past,
1045                                o->branch1, o->branch1, path, renamed);
1046                         update_file(o, 0, a_sha, a_mode, renamed);
1047                 }
1048                 /*
1049                  * No need to call update_file() on path when !renamed, since
1050                  * that would needlessly touch path.  We could call
1051                  * update_file_flags() with update_cache=0 and update_wd=0,
1052                  * but that's a no-op.
1053                  */
1054         }
1055         free(renamed);
1056 }
1057
1058 static void conflict_rename_delete(struct merge_options *o,
1059                                    struct diff_filepair *pair,
1060                                    const char *rename_branch,
1061                                    const char *other_branch)
1062 {
1063         const struct diff_filespec *orig = pair->one;
1064         const struct diff_filespec *dest = pair->two;
1065         const unsigned char *a_sha = NULL;
1066         const unsigned char *b_sha = NULL;
1067         int a_mode = 0;
1068         int b_mode = 0;
1069
1070         if (rename_branch == o->branch1) {
1071                 a_sha = dest->sha1;
1072                 a_mode = dest->mode;
1073         } else {
1074                 b_sha = dest->sha1;
1075                 b_mode = dest->mode;
1076         }
1077
1078         handle_change_delete(o,
1079                              o->call_depth ? orig->path : dest->path,
1080                              orig->sha1, orig->mode,
1081                              a_sha, a_mode,
1082                              b_sha, b_mode,
1083                              _("rename"), _("renamed"));
1084
1085         if (o->call_depth) {
1086                 remove_file_from_cache(dest->path);
1087         } else {
1088                 update_stages(dest->path, NULL,
1089                               rename_branch == o->branch1 ? dest : NULL,
1090                               rename_branch == o->branch1 ? NULL : dest);
1091         }
1092
1093 }
1094
1095 static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1096                                                  struct stage_data *entry,
1097                                                  int stage)
1098 {
1099         unsigned char *sha = entry->stages[stage].sha;
1100         unsigned mode = entry->stages[stage].mode;
1101         if (mode == 0 || is_null_sha1(sha))
1102                 return NULL;
1103         hashcpy(target->sha1, sha);
1104         target->mode = mode;
1105         return target;
1106 }
1107
1108 static void handle_file(struct merge_options *o,
1109                         struct diff_filespec *rename,
1110                         int stage,
1111                         struct rename_conflict_info *ci)
1112 {
1113         char *dst_name = rename->path;
1114         struct stage_data *dst_entry;
1115         const char *cur_branch, *other_branch;
1116         struct diff_filespec other;
1117         struct diff_filespec *add;
1118
1119         if (stage == 2) {
1120                 dst_entry = ci->dst_entry1;
1121                 cur_branch = ci->branch1;
1122                 other_branch = ci->branch2;
1123         } else {
1124                 dst_entry = ci->dst_entry2;
1125                 cur_branch = ci->branch2;
1126                 other_branch = ci->branch1;
1127         }
1128
1129         add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1130         if (add) {
1131                 char *add_name = unique_path(o, rename->path, other_branch);
1132                 update_file(o, 0, add->sha1, add->mode, add_name);
1133
1134                 remove_file(o, 0, rename->path, 0);
1135                 dst_name = unique_path(o, rename->path, cur_branch);
1136         } else {
1137                 if (dir_in_way(rename->path, !o->call_depth)) {
1138                         dst_name = unique_path(o, rename->path, cur_branch);
1139                         output(o, 1, _("%s is a directory in %s adding as %s instead"),
1140                                rename->path, other_branch, dst_name);
1141                 }
1142         }
1143         update_file(o, 0, rename->sha1, rename->mode, dst_name);
1144         if (stage == 2)
1145                 update_stages(rename->path, NULL, rename, add);
1146         else
1147                 update_stages(rename->path, NULL, add, rename);
1148
1149         if (dst_name != rename->path)
1150                 free(dst_name);
1151 }
1152
1153 static void conflict_rename_rename_1to2(struct merge_options *o,
1154                                         struct rename_conflict_info *ci)
1155 {
1156         /* One file was renamed in both branches, but to different names. */
1157         struct diff_filespec *one = ci->pair1->one;
1158         struct diff_filespec *a = ci->pair1->two;
1159         struct diff_filespec *b = ci->pair2->two;
1160
1161         output(o, 1, _("CONFLICT (rename/rename): "
1162                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1163                "rename \"%s\"->\"%s\" in \"%s\"%s"),
1164                one->path, a->path, ci->branch1,
1165                one->path, b->path, ci->branch2,
1166                o->call_depth ? _(" (left unresolved)") : "");
1167         if (o->call_depth) {
1168                 struct merge_file_info mfi;
1169                 struct diff_filespec other;
1170                 struct diff_filespec *add;
1171                 mfi = merge_file_one(o, one->path,
1172                                  one->sha1, one->mode,
1173                                  a->sha1, a->mode,
1174                                  b->sha1, b->mode,
1175                                  ci->branch1, ci->branch2);
1176                 /*
1177                  * FIXME: For rename/add-source conflicts (if we could detect
1178                  * such), this is wrong.  We should instead find a unique
1179                  * pathname and then either rename the add-source file to that
1180                  * unique path, or use that unique path instead of src here.
1181                  */
1182                 update_file(o, 0, mfi.sha, mfi.mode, one->path);
1183
1184                 /*
1185                  * Above, we put the merged content at the merge-base's
1186                  * path.  Now we usually need to delete both a->path and
1187                  * b->path.  However, the rename on each side of the merge
1188                  * could also be involved in a rename/add conflict.  In
1189                  * such cases, we should keep the added file around,
1190                  * resolving the conflict at that path in its favor.
1191                  */
1192                 add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1193                 if (add)
1194                         update_file(o, 0, add->sha1, add->mode, a->path);
1195                 else
1196                         remove_file_from_cache(a->path);
1197                 add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1198                 if (add)
1199                         update_file(o, 0, add->sha1, add->mode, b->path);
1200                 else
1201                         remove_file_from_cache(b->path);
1202         } else {
1203                 handle_file(o, a, 2, ci);
1204                 handle_file(o, b, 3, ci);
1205         }
1206 }
1207
1208 static void conflict_rename_rename_2to1(struct merge_options *o,
1209                                         struct rename_conflict_info *ci)
1210 {
1211         /* Two files, a & b, were renamed to the same thing, c. */
1212         struct diff_filespec *a = ci->pair1->one;
1213         struct diff_filespec *b = ci->pair2->one;
1214         struct diff_filespec *c1 = ci->pair1->two;
1215         struct diff_filespec *c2 = ci->pair2->two;
1216         char *path = c1->path; /* == c2->path */
1217         struct merge_file_info mfi_c1;
1218         struct merge_file_info mfi_c2;
1219
1220         output(o, 1, _("CONFLICT (rename/rename): "
1221                "Rename %s->%s in %s. "
1222                "Rename %s->%s in %s"),
1223                a->path, c1->path, ci->branch1,
1224                b->path, c2->path, ci->branch2);
1225
1226         remove_file(o, 1, a->path, would_lose_untracked(a->path));
1227         remove_file(o, 1, b->path, would_lose_untracked(b->path));
1228
1229         mfi_c1 = merge_file_special_markers(o, a, c1, &ci->ren1_other,
1230                                             o->branch1, c1->path,
1231                                             o->branch2, ci->ren1_other.path);
1232         mfi_c2 = merge_file_special_markers(o, b, &ci->ren2_other, c2,
1233                                             o->branch1, ci->ren2_other.path,
1234                                             o->branch2, c2->path);
1235
1236         if (o->call_depth) {
1237                 /*
1238                  * If mfi_c1.clean && mfi_c2.clean, then it might make
1239                  * sense to do a two-way merge of those results.  But, I
1240                  * think in all cases, it makes sense to have the virtual
1241                  * merge base just undo the renames; they can be detected
1242                  * again later for the non-recursive merge.
1243                  */
1244                 remove_file(o, 0, path, 0);
1245                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, a->path);
1246                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, b->path);
1247         } else {
1248                 char *new_path1 = unique_path(o, path, ci->branch1);
1249                 char *new_path2 = unique_path(o, path, ci->branch2);
1250                 output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1251                        a->path, new_path1, b->path, new_path2);
1252                 remove_file(o, 0, path, 0);
1253                 update_file(o, 0, mfi_c1.sha, mfi_c1.mode, new_path1);
1254                 update_file(o, 0, mfi_c2.sha, mfi_c2.mode, new_path2);
1255                 free(new_path2);
1256                 free(new_path1);
1257         }
1258 }
1259
1260 static int process_renames(struct merge_options *o,
1261                            struct string_list *a_renames,
1262                            struct string_list *b_renames)
1263 {
1264         int clean_merge = 1, i, j;
1265         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1266         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1267         const struct rename *sre;
1268
1269         for (i = 0; i < a_renames->nr; i++) {
1270                 sre = a_renames->items[i].util;
1271                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
1272                         = (void *)sre;
1273         }
1274         for (i = 0; i < b_renames->nr; i++) {
1275                 sre = b_renames->items[i].util;
1276                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
1277                         = (void *)sre;
1278         }
1279
1280         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1281                 struct string_list *renames1, *renames2Dst;
1282                 struct rename *ren1 = NULL, *ren2 = NULL;
1283                 const char *branch1, *branch2;
1284                 const char *ren1_src, *ren1_dst;
1285                 struct string_list_item *lookup;
1286
1287                 if (i >= a_renames->nr) {
1288                         ren2 = b_renames->items[j++].util;
1289                 } else if (j >= b_renames->nr) {
1290                         ren1 = a_renames->items[i++].util;
1291                 } else {
1292                         int compare = strcmp(a_renames->items[i].string,
1293                                              b_renames->items[j].string);
1294                         if (compare <= 0)
1295                                 ren1 = a_renames->items[i++].util;
1296                         if (compare >= 0)
1297                                 ren2 = b_renames->items[j++].util;
1298                 }
1299
1300                 /* TODO: refactor, so that 1/2 are not needed */
1301                 if (ren1) {
1302                         renames1 = a_renames;
1303                         renames2Dst = &b_by_dst;
1304                         branch1 = o->branch1;
1305                         branch2 = o->branch2;
1306                 } else {
1307                         struct rename *tmp;
1308                         renames1 = b_renames;
1309                         renames2Dst = &a_by_dst;
1310                         branch1 = o->branch2;
1311                         branch2 = o->branch1;
1312                         tmp = ren2;
1313                         ren2 = ren1;
1314                         ren1 = tmp;
1315                 }
1316
1317                 if (ren1->processed)
1318                         continue;
1319                 ren1->processed = 1;
1320                 ren1->dst_entry->processed = 1;
1321                 /* BUG: We should only mark src_entry as processed if we
1322                  * are not dealing with a rename + add-source case.
1323                  */
1324                 ren1->src_entry->processed = 1;
1325
1326                 ren1_src = ren1->pair->one->path;
1327                 ren1_dst = ren1->pair->two->path;
1328
1329                 if (ren2) {
1330                         /* One file renamed on both sides */
1331                         const char *ren2_src = ren2->pair->one->path;
1332                         const char *ren2_dst = ren2->pair->two->path;
1333                         enum rename_type rename_type;
1334                         if (strcmp(ren1_src, ren2_src) != 0)
1335                                 die("ren1_src != ren2_src");
1336                         ren2->dst_entry->processed = 1;
1337                         ren2->processed = 1;
1338                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1339                                 rename_type = RENAME_ONE_FILE_TO_TWO;
1340                                 clean_merge = 0;
1341                         } else {
1342                                 rename_type = RENAME_ONE_FILE_TO_ONE;
1343                                 /* BUG: We should only remove ren1_src in
1344                                  * the base stage (think of rename +
1345                                  * add-source cases).
1346                                  */
1347                                 remove_file(o, 1, ren1_src, 1);
1348                                 update_entry(ren1->dst_entry,
1349                                              ren1->pair->one,
1350                                              ren1->pair->two,
1351                                              ren2->pair->two);
1352                         }
1353                         setup_rename_conflict_info(rename_type,
1354                                                    ren1->pair,
1355                                                    ren2->pair,
1356                                                    branch1,
1357                                                    branch2,
1358                                                    ren1->dst_entry,
1359                                                    ren2->dst_entry,
1360                                                    o,
1361                                                    NULL,
1362                                                    NULL);
1363                 } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1364                         /* Two different files renamed to the same thing */
1365                         char *ren2_dst;
1366                         ren2 = lookup->util;
1367                         ren2_dst = ren2->pair->two->path;
1368                         if (strcmp(ren1_dst, ren2_dst) != 0)
1369                                 die("ren1_dst != ren2_dst");
1370
1371                         clean_merge = 0;
1372                         ren2->processed = 1;
1373                         /*
1374                          * BUG: We should only mark src_entry as processed
1375                          * if we are not dealing with a rename + add-source
1376                          * case.
1377                          */
1378                         ren2->src_entry->processed = 1;
1379
1380                         setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1381                                                    ren1->pair,
1382                                                    ren2->pair,
1383                                                    branch1,
1384                                                    branch2,
1385                                                    ren1->dst_entry,
1386                                                    ren2->dst_entry,
1387                                                    o,
1388                                                    ren1->src_entry,
1389                                                    ren2->src_entry);
1390
1391                 } else {
1392                         /* Renamed in 1, maybe changed in 2 */
1393                         /* we only use sha1 and mode of these */
1394                         struct diff_filespec src_other, dst_other;
1395                         int try_merge;
1396
1397                         /*
1398                          * unpack_trees loads entries from common-commit
1399                          * into stage 1, from head-commit into stage 2, and
1400                          * from merge-commit into stage 3.  We keep track
1401                          * of which side corresponds to the rename.
1402                          */
1403                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1404                         int other_stage =   a_renames == renames1 ? 3 : 2;
1405
1406                         /* BUG: We should only remove ren1_src in the base
1407                          * stage and in other_stage (think of rename +
1408                          * add-source case).
1409                          */
1410                         remove_file(o, 1, ren1_src,
1411                                     renamed_stage == 2 || !was_tracked(ren1_src));
1412
1413                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1414                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1415                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1416                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1417                         try_merge = 0;
1418
1419                         if (sha_eq(src_other.sha1, null_sha1)) {
1420                                 setup_rename_conflict_info(RENAME_DELETE,
1421                                                            ren1->pair,
1422                                                            NULL,
1423                                                            branch1,
1424                                                            branch2,
1425                                                            ren1->dst_entry,
1426                                                            NULL,
1427                                                            o,
1428                                                            NULL,
1429                                                            NULL);
1430                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1431                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1432                                 /*
1433                                  * Added file on the other side identical to
1434                                  * the file being renamed: clean merge.
1435                                  * Also, there is no need to overwrite the
1436                                  * file already in the working copy, so call
1437                                  * update_file_flags() instead of
1438                                  * update_file().
1439                                  */
1440                                 update_file_flags(o,
1441                                                   ren1->pair->two->sha1,
1442                                                   ren1->pair->two->mode,
1443                                                   ren1_dst,
1444                                                   1, /* update_cache */
1445                                                   0  /* update_wd    */);
1446                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1447                                 clean_merge = 0;
1448                                 try_merge = 1;
1449                                 output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1450                                        "%s added in %s"),
1451                                        ren1_src, ren1_dst, branch1,
1452                                        ren1_dst, branch2);
1453                                 if (o->call_depth) {
1454                                         struct merge_file_info mfi;
1455                                         mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
1456                                                          ren1->pair->two->sha1, ren1->pair->two->mode,
1457                                                          dst_other.sha1, dst_other.mode,
1458                                                          branch1, branch2);
1459                                         output(o, 1, _("Adding merged %s"), ren1_dst);
1460                                         update_file(o, 0, mfi.sha, mfi.mode, ren1_dst);
1461                                         try_merge = 0;
1462                                 } else {
1463                                         char *new_path = unique_path(o, ren1_dst, branch2);
1464                                         output(o, 1, _("Adding as %s instead"), new_path);
1465                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1466                                         free(new_path);
1467                                 }
1468                         } else
1469                                 try_merge = 1;
1470
1471                         if (try_merge) {
1472                                 struct diff_filespec *one, *a, *b;
1473                                 src_other.path = (char *)ren1_src;
1474
1475                                 one = ren1->pair->one;
1476                                 if (a_renames == renames1) {
1477                                         a = ren1->pair->two;
1478                                         b = &src_other;
1479                                 } else {
1480                                         b = ren1->pair->two;
1481                                         a = &src_other;
1482                                 }
1483                                 update_entry(ren1->dst_entry, one, a, b);
1484                                 setup_rename_conflict_info(RENAME_NORMAL,
1485                                                            ren1->pair,
1486                                                            NULL,
1487                                                            branch1,
1488                                                            NULL,
1489                                                            ren1->dst_entry,
1490                                                            NULL,
1491                                                            o,
1492                                                            NULL,
1493                                                            NULL);
1494                         }
1495                 }
1496         }
1497         string_list_clear(&a_by_dst, 0);
1498         string_list_clear(&b_by_dst, 0);
1499
1500         return clean_merge;
1501 }
1502
1503 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1504 {
1505         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1506 }
1507
1508 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1509 {
1510         void *buf;
1511         enum object_type type;
1512         unsigned long size;
1513         buf = read_sha1_file(sha1, &type, &size);
1514         if (!buf)
1515                 return error(_("cannot read object %s"), sha1_to_hex(sha1));
1516         if (type != OBJ_BLOB) {
1517                 free(buf);
1518                 return error(_("object %s is not a blob"), sha1_to_hex(sha1));
1519         }
1520         strbuf_attach(dst, buf, size, size + 1);
1521         return 0;
1522 }
1523
1524 static int blob_unchanged(const unsigned char *o_sha,
1525                           const unsigned char *a_sha,
1526                           int renormalize, const char *path)
1527 {
1528         struct strbuf o = STRBUF_INIT;
1529         struct strbuf a = STRBUF_INIT;
1530         int ret = 0; /* assume changed for safety */
1531
1532         if (sha_eq(o_sha, a_sha))
1533                 return 1;
1534         if (!renormalize)
1535                 return 0;
1536
1537         assert(o_sha && a_sha);
1538         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1539                 goto error_return;
1540         /*
1541          * Note: binary | is used so that both renormalizations are
1542          * performed.  Comparison can be skipped if both files are
1543          * unchanged since their sha1s have already been compared.
1544          */
1545         if (renormalize_buffer(path, o.buf, o.len, &o) |
1546             renormalize_buffer(path, a.buf, o.len, &a))
1547                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1548
1549 error_return:
1550         strbuf_release(&o);
1551         strbuf_release(&a);
1552         return ret;
1553 }
1554
1555 static void handle_modify_delete(struct merge_options *o,
1556                                  const char *path,
1557                                  unsigned char *o_sha, int o_mode,
1558                                  unsigned char *a_sha, int a_mode,
1559                                  unsigned char *b_sha, int b_mode)
1560 {
1561         handle_change_delete(o,
1562                              path,
1563                              o_sha, o_mode,
1564                              a_sha, a_mode,
1565                              b_sha, b_mode,
1566                              _("modify"), _("modified"));
1567 }
1568
1569 static int merge_content(struct merge_options *o,
1570                          const char *path,
1571                          unsigned char *o_sha, int o_mode,
1572                          unsigned char *a_sha, int a_mode,
1573                          unsigned char *b_sha, int b_mode,
1574                          struct rename_conflict_info *rename_conflict_info)
1575 {
1576         const char *reason = _("content");
1577         const char *path1 = NULL, *path2 = NULL;
1578         struct merge_file_info mfi;
1579         struct diff_filespec one, a, b;
1580         unsigned df_conflict_remains = 0;
1581
1582         if (!o_sha) {
1583                 reason = _("add/add");
1584                 o_sha = (unsigned char *)null_sha1;
1585         }
1586         one.path = a.path = b.path = (char *)path;
1587         hashcpy(one.sha1, o_sha);
1588         one.mode = o_mode;
1589         hashcpy(a.sha1, a_sha);
1590         a.mode = a_mode;
1591         hashcpy(b.sha1, b_sha);
1592         b.mode = b_mode;
1593
1594         if (rename_conflict_info) {
1595                 struct diff_filepair *pair1 = rename_conflict_info->pair1;
1596
1597                 path1 = (o->branch1 == rename_conflict_info->branch1) ?
1598                         pair1->two->path : pair1->one->path;
1599                 /* If rename_conflict_info->pair2 != NULL, we are in
1600                  * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1601                  * normal rename.
1602                  */
1603                 path2 = (rename_conflict_info->pair2 ||
1604                          o->branch2 == rename_conflict_info->branch1) ?
1605                         pair1->two->path : pair1->one->path;
1606
1607                 if (dir_in_way(path, !o->call_depth))
1608                         df_conflict_remains = 1;
1609         }
1610         mfi = merge_file_special_markers(o, &one, &a, &b,
1611                                          o->branch1, path1,
1612                                          o->branch2, path2);
1613
1614         if (mfi.clean && !df_conflict_remains &&
1615             sha_eq(mfi.sha, a_sha) && mfi.mode == a_mode) {
1616                 int path_renamed_outside_HEAD;
1617                 output(o, 3, _("Skipped %s (merged same as existing)"), path);
1618                 /*
1619                  * The content merge resulted in the same file contents we
1620                  * already had.  We can return early if those file contents
1621                  * are recorded at the correct path (which may not be true
1622                  * if the merge involves a rename).
1623                  */
1624                 path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1625                 if (!path_renamed_outside_HEAD) {
1626                         add_cacheinfo(mfi.mode, mfi.sha, path,
1627                                       0, (!o->call_depth), 0);
1628                         return mfi.clean;
1629                 }
1630         } else
1631                 output(o, 2, _("Auto-merging %s"), path);
1632
1633         if (!mfi.clean) {
1634                 if (S_ISGITLINK(mfi.mode))
1635                         reason = _("submodule");
1636                 output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1637                                 reason, path);
1638                 if (rename_conflict_info && !df_conflict_remains)
1639                         update_stages(path, &one, &a, &b);
1640         }
1641
1642         if (df_conflict_remains) {
1643                 char *new_path;
1644                 if (o->call_depth) {
1645                         remove_file_from_cache(path);
1646                 } else {
1647                         if (!mfi.clean)
1648                                 update_stages(path, &one, &a, &b);
1649                         else {
1650                                 int file_from_stage2 = was_tracked(path);
1651                                 struct diff_filespec merged;
1652                                 hashcpy(merged.sha1, mfi.sha);
1653                                 merged.mode = mfi.mode;
1654
1655                                 update_stages(path, NULL,
1656                                               file_from_stage2 ? &merged : NULL,
1657                                               file_from_stage2 ? NULL : &merged);
1658                         }
1659
1660                 }
1661                 new_path = unique_path(o, path, rename_conflict_info->branch1);
1662                 output(o, 1, _("Adding as %s instead"), new_path);
1663                 update_file(o, 0, mfi.sha, mfi.mode, new_path);
1664                 free(new_path);
1665                 mfi.clean = 0;
1666         } else {
1667                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1668         }
1669         return mfi.clean;
1670
1671 }
1672
1673 /* Per entry merge function */
1674 static int process_entry(struct merge_options *o,
1675                          const char *path, struct stage_data *entry)
1676 {
1677         /*
1678         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1679         print_index_entry("\tpath: ", entry);
1680         */
1681         int clean_merge = 1;
1682         int normalize = o->renormalize;
1683         unsigned o_mode = entry->stages[1].mode;
1684         unsigned a_mode = entry->stages[2].mode;
1685         unsigned b_mode = entry->stages[3].mode;
1686         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1687         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1688         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1689
1690         entry->processed = 1;
1691         if (entry->rename_conflict_info) {
1692                 struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1693                 switch (conflict_info->rename_type) {
1694                 case RENAME_NORMAL:
1695                 case RENAME_ONE_FILE_TO_ONE:
1696                         clean_merge = merge_content(o, path,
1697                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1698                                                     conflict_info);
1699                         break;
1700                 case RENAME_DELETE:
1701                         clean_merge = 0;
1702                         conflict_rename_delete(o, conflict_info->pair1,
1703                                                conflict_info->branch1,
1704                                                conflict_info->branch2);
1705                         break;
1706                 case RENAME_ONE_FILE_TO_TWO:
1707                         clean_merge = 0;
1708                         conflict_rename_rename_1to2(o, conflict_info);
1709                         break;
1710                 case RENAME_TWO_FILES_TO_ONE:
1711                         clean_merge = 0;
1712                         conflict_rename_rename_2to1(o, conflict_info);
1713                         break;
1714                 default:
1715                         entry->processed = 0;
1716                         break;
1717                 }
1718         } else if (o_sha && (!a_sha || !b_sha)) {
1719                 /* Case A: Deleted in one */
1720                 if ((!a_sha && !b_sha) ||
1721                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1722                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1723                         /* Deleted in both or deleted in one and
1724                          * unchanged in the other */
1725                         if (a_sha)
1726                                 output(o, 2, _("Removing %s"), path);
1727                         /* do not touch working file if it did not exist */
1728                         remove_file(o, 1, path, !a_sha);
1729                 } else {
1730                         /* Modify/delete; deleted side may have put a directory in the way */
1731                         clean_merge = 0;
1732                         handle_modify_delete(o, path, o_sha, o_mode,
1733                                              a_sha, a_mode, b_sha, b_mode);
1734                 }
1735         } else if ((!o_sha && a_sha && !b_sha) ||
1736                    (!o_sha && !a_sha && b_sha)) {
1737                 /* Case B: Added in one. */
1738                 /* [nothing|directory] -> ([nothing|directory], file) */
1739
1740                 const char *add_branch;
1741                 const char *other_branch;
1742                 unsigned mode;
1743                 const unsigned char *sha;
1744                 const char *conf;
1745
1746                 if (a_sha) {
1747                         add_branch = o->branch1;
1748                         other_branch = o->branch2;
1749                         mode = a_mode;
1750                         sha = a_sha;
1751                         conf = _("file/directory");
1752                 } else {
1753                         add_branch = o->branch2;
1754                         other_branch = o->branch1;
1755                         mode = b_mode;
1756                         sha = b_sha;
1757                         conf = _("directory/file");
1758                 }
1759                 if (dir_in_way(path, !o->call_depth)) {
1760                         char *new_path = unique_path(o, path, add_branch);
1761                         clean_merge = 0;
1762                         output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1763                                "Adding %s as %s"),
1764                                conf, path, other_branch, path, new_path);
1765                         if (o->call_depth)
1766                                 remove_file_from_cache(path);
1767                         update_file(o, 0, sha, mode, new_path);
1768                         if (o->call_depth)
1769                                 remove_file_from_cache(path);
1770                         free(new_path);
1771                 } else {
1772                         output(o, 2, _("Adding %s"), path);
1773                         /* do not overwrite file if already present */
1774                         update_file_flags(o, sha, mode, path, 1, !a_sha);
1775                 }
1776         } else if (a_sha && b_sha) {
1777                 /* Case C: Added in both (check for same permissions) and */
1778                 /* case D: Modified in both, but differently. */
1779                 clean_merge = merge_content(o, path,
1780                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1781                                             NULL);
1782         } else if (!o_sha && !a_sha && !b_sha) {
1783                 /*
1784                  * this entry was deleted altogether. a_mode == 0 means
1785                  * we had that path and want to actively remove it.
1786                  */
1787                 remove_file(o, 1, path, !a_mode);
1788         } else
1789                 die(_("Fatal merge failure, shouldn't happen."));
1790
1791         return clean_merge;
1792 }
1793
1794 int merge_trees(struct merge_options *o,
1795                 struct tree *head,
1796                 struct tree *merge,
1797                 struct tree *common,
1798                 struct tree **result)
1799 {
1800         int code, clean;
1801
1802         if (o->subtree_shift) {
1803                 merge = shift_tree_object(head, merge, o->subtree_shift);
1804                 common = shift_tree_object(head, common, o->subtree_shift);
1805         }
1806
1807         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1808                 output(o, 0, _("Already up-to-date!"));
1809                 *result = head;
1810                 return 1;
1811         }
1812
1813         code = git_merge_trees(o->call_depth, common, head, merge);
1814
1815         if (code != 0) {
1816                 if (show(o, 4) || o->call_depth)
1817                         die(_("merging of trees %s and %s failed"),
1818                             sha1_to_hex(head->object.sha1),
1819                             sha1_to_hex(merge->object.sha1));
1820                 else
1821                         exit(128);
1822         }
1823
1824         if (unmerged_cache()) {
1825                 struct string_list *entries, *re_head, *re_merge;
1826                 int i;
1827                 string_list_clear(&o->current_file_set, 1);
1828                 string_list_clear(&o->current_directory_set, 1);
1829                 get_files_dirs(o, head);
1830                 get_files_dirs(o, merge);
1831
1832                 entries = get_unmerged();
1833                 record_df_conflict_files(o, entries);
1834                 re_head  = get_renames(o, head, common, head, merge, entries);
1835                 re_merge = get_renames(o, merge, common, head, merge, entries);
1836                 clean = process_renames(o, re_head, re_merge);
1837                 for (i = entries->nr-1; 0 <= i; i--) {
1838                         const char *path = entries->items[i].string;
1839                         struct stage_data *e = entries->items[i].util;
1840                         if (!e->processed
1841                                 && !process_entry(o, path, e))
1842                                 clean = 0;
1843                 }
1844                 for (i = 0; i < entries->nr; i++) {
1845                         struct stage_data *e = entries->items[i].util;
1846                         if (!e->processed)
1847                                 die(_("Unprocessed path??? %s"),
1848                                     entries->items[i].string);
1849                 }
1850
1851                 string_list_clear(re_merge, 0);
1852                 string_list_clear(re_head, 0);
1853                 string_list_clear(entries, 1);
1854
1855         }
1856         else
1857                 clean = 1;
1858
1859         if (o->call_depth)
1860                 *result = write_tree_from_memory(o);
1861
1862         return clean;
1863 }
1864
1865 static struct commit_list *reverse_commit_list(struct commit_list *list)
1866 {
1867         struct commit_list *next = NULL, *current, *backup;
1868         for (current = list; current; current = backup) {
1869                 backup = current->next;
1870                 current->next = next;
1871                 next = current;
1872         }
1873         return next;
1874 }
1875
1876 /*
1877  * Merge the commits h1 and h2, return the resulting virtual
1878  * commit object and a flag indicating the cleanness of the merge.
1879  */
1880 int merge_recursive(struct merge_options *o,
1881                     struct commit *h1,
1882                     struct commit *h2,
1883                     struct commit_list *ca,
1884                     struct commit **result)
1885 {
1886         struct commit_list *iter;
1887         struct commit *merged_common_ancestors;
1888         struct tree *mrtree = mrtree;
1889         int clean;
1890
1891         if (show(o, 4)) {
1892                 output(o, 4, _("Merging:"));
1893                 output_commit_title(o, h1);
1894                 output_commit_title(o, h2);
1895         }
1896
1897         if (!ca) {
1898                 ca = get_merge_bases(h1, h2, 1);
1899                 ca = reverse_commit_list(ca);
1900         }
1901
1902         if (show(o, 5)) {
1903                 unsigned cnt = commit_list_count(ca);
1904
1905                 output(o, 5, Q_("found %u common ancestor:",
1906                                 "found %u common ancestors:", cnt), cnt);
1907                 for (iter = ca; iter; iter = iter->next)
1908                         output_commit_title(o, iter->item);
1909         }
1910
1911         merged_common_ancestors = pop_commit(&ca);
1912         if (merged_common_ancestors == NULL) {
1913                 /* if there is no common ancestor, use an empty tree */
1914                 struct tree *tree;
1915
1916                 tree = lookup_tree(EMPTY_TREE_SHA1_BIN);
1917                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1918         }
1919
1920         for (iter = ca; iter; iter = iter->next) {
1921                 const char *saved_b1, *saved_b2;
1922                 o->call_depth++;
1923                 /*
1924                  * When the merge fails, the result contains files
1925                  * with conflict markers. The cleanness flag is
1926                  * ignored, it was never actually used, as result of
1927                  * merge_trees has always overwritten it: the committed
1928                  * "conflicts" were already resolved.
1929                  */
1930                 discard_cache();
1931                 saved_b1 = o->branch1;
1932                 saved_b2 = o->branch2;
1933                 o->branch1 = "Temporary merge branch 1";
1934                 o->branch2 = "Temporary merge branch 2";
1935                 merge_recursive(o, merged_common_ancestors, iter->item,
1936                                 NULL, &merged_common_ancestors);
1937                 o->branch1 = saved_b1;
1938                 o->branch2 = saved_b2;
1939                 o->call_depth--;
1940
1941                 if (!merged_common_ancestors)
1942                         die(_("merge returned no commit"));
1943         }
1944
1945         discard_cache();
1946         if (!o->call_depth)
1947                 read_cache();
1948
1949         o->ancestor = "merged common ancestors";
1950         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1951                             &mrtree);
1952
1953         if (o->call_depth) {
1954                 *result = make_virtual_commit(mrtree, "merged tree");
1955                 commit_list_insert(h1, &(*result)->parents);
1956                 commit_list_insert(h2, &(*result)->parents->next);
1957         }
1958         flush_output(o);
1959         if (show(o, 2))
1960                 diff_warn_rename_limit("merge.renamelimit",
1961                                        o->needed_rename_limit, 0);
1962         return clean;
1963 }
1964
1965 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1966 {
1967         struct object *object;
1968
1969         object = deref_tag(parse_object(sha1), name, strlen(name));
1970         if (!object)
1971                 return NULL;
1972         if (object->type == OBJ_TREE)
1973                 return make_virtual_commit((struct tree*)object, name);
1974         if (object->type != OBJ_COMMIT)
1975                 return NULL;
1976         if (parse_commit((struct commit *)object))
1977                 return NULL;
1978         return (struct commit *)object;
1979 }
1980
1981 int merge_recursive_generic(struct merge_options *o,
1982                             const unsigned char *head,
1983                             const unsigned char *merge,
1984                             int num_base_list,
1985                             const unsigned char **base_list,
1986                             struct commit **result)
1987 {
1988         int clean, index_fd;
1989         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1990         struct commit *head_commit = get_ref(head, o->branch1);
1991         struct commit *next_commit = get_ref(merge, o->branch2);
1992         struct commit_list *ca = NULL;
1993
1994         if (base_list) {
1995                 int i;
1996                 for (i = 0; i < num_base_list; ++i) {
1997                         struct commit *base;
1998                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1999                                 return error(_("Could not parse object '%s'"),
2000                                         sha1_to_hex(base_list[i]));
2001                         commit_list_insert(base, &ca);
2002                 }
2003         }
2004
2005         index_fd = hold_locked_index(lock, 1);
2006         clean = merge_recursive(o, head_commit, next_commit, ca,
2007                         result);
2008         if (active_cache_changed &&
2009                         (write_cache(index_fd, active_cache, active_nr) ||
2010                          commit_locked_index(lock)))
2011                 return error(_("Unable to write index."));
2012
2013         return clean ? 0 : 1;
2014 }
2015
2016 static int merge_recursive_config(const char *var, const char *value, void *cb)
2017 {
2018         struct merge_options *o = cb;
2019         if (!strcmp(var, "merge.verbosity")) {
2020                 o->verbosity = git_config_int(var, value);
2021                 return 0;
2022         }
2023         if (!strcmp(var, "diff.renamelimit")) {
2024                 o->diff_rename_limit = git_config_int(var, value);
2025                 return 0;
2026         }
2027         if (!strcmp(var, "merge.renamelimit")) {
2028                 o->merge_rename_limit = git_config_int(var, value);
2029                 return 0;
2030         }
2031         return git_xmerge_config(var, value, cb);
2032 }
2033
2034 void init_merge_options(struct merge_options *o)
2035 {
2036         memset(o, 0, sizeof(struct merge_options));
2037         o->verbosity = 2;
2038         o->buffer_output = 1;
2039         o->diff_rename_limit = -1;
2040         o->merge_rename_limit = -1;
2041         o->renormalize = 0;
2042         git_config(merge_recursive_config, o);
2043         if (getenv("GIT_MERGE_VERBOSITY"))
2044                 o->verbosity =
2045                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2046         if (o->verbosity >= 5)
2047                 o->buffer_output = 0;
2048         strbuf_init(&o->obuf, 0);
2049         memset(&o->current_file_set, 0, sizeof(struct string_list));
2050         o->current_file_set.strdup_strings = 1;
2051         memset(&o->current_directory_set, 0, sizeof(struct string_list));
2052         o->current_directory_set.strdup_strings = 1;
2053         memset(&o->df_conflict_file_set, 0, sizeof(struct string_list));
2054         o->df_conflict_file_set.strdup_strings = 1;
2055 }
2056
2057 int parse_merge_opt(struct merge_options *o, const char *s)
2058 {
2059         if (!s || !*s)
2060                 return -1;
2061         if (!strcmp(s, "ours"))
2062                 o->recursive_variant = MERGE_RECURSIVE_OURS;
2063         else if (!strcmp(s, "theirs"))
2064                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2065         else if (!strcmp(s, "subtree"))
2066                 o->subtree_shift = "";
2067         else if (!prefixcmp(s, "subtree="))
2068                 o->subtree_shift = s + strlen("subtree=");
2069         else if (!strcmp(s, "patience"))
2070                 o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2071         else if (!strcmp(s, "histogram"))
2072                 o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2073         else if (!prefixcmp(s, "diff-algorithm=")) {
2074                 long value = parse_algorithm_value(s + strlen("diff-algorithm="));
2075                 if (value < 0)
2076                         return -1;
2077                 /* clear out previous settings */
2078                 DIFF_XDL_CLR(o, NEED_MINIMAL);
2079                 o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2080                 o->xdl_opts |= value;
2081         }
2082         else if (!strcmp(s, "ignore-space-change"))
2083                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2084         else if (!strcmp(s, "ignore-all-space"))
2085                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2086         else if (!strcmp(s, "ignore-space-at-eol"))
2087                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2088         else if (!strcmp(s, "renormalize"))
2089                 o->renormalize = 1;
2090         else if (!strcmp(s, "no-renormalize"))
2091                 o->renormalize = 0;
2092         else if (!prefixcmp(s, "rename-threshold=")) {
2093                 const char *score = s + strlen("rename-threshold=");
2094                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
2095                         return -1;
2096         }
2097         else
2098                 return -1;
2099         return 0;
2100 }