merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "advice.h"
   7 #include "cache.h"
   8 #include "cache-tree.h"
   9 #include "commit.h"
  10 #include "blob.h"
  11 #include "builtin.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "tag.h"
  16 #include "unpack-trees.h"
  17 #include "string-list.h"
  18 #include "xdiff-interface.h"
  19 #include "ll-merge.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22 #include "dir.h"
  23 #include "submodule.h"
  24
  25 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  26                                       const char *subtree_shift)
  27 {
  28         unsigned char shifted[20];
  29
  30         if (!*subtree_shift) {
  31                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  32         } else {
  33                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  34                               subtree_shift);
  35         }
  36         if (!hashcmp(two->object.sha1, shifted))
  37                 return two;
  38         return lookup_tree(shifted);
  39 }
  40
  41 /*
  42  * A virtual commit has (const char *)commit->util set to the name.
  43  */
  44
  45 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  46 {
  47         struct commit *commit = xcalloc(1, sizeof(struct commit));
  48         commit->tree = tree;
  49         commit->util = (void*)comment;
  50         /* avoid warnings */
  51         commit->object.parsed = 1;
  52         return commit;
  53 }
  54
  55 /*
  56  * Since we use get_tree_entry(), which does not put the read object into
  57  * the object pool, we cannot rely on a == b.
  58  */
  59 static int sha_eq(const unsigned char *a, const unsigned char *b)
  60 {
  61         if (!a && !b)
  62                 return 2;
  63         return a && b && hashcmp(a, b) == 0;
  64 }
  65
  66 enum rename_type {
  67         RENAME_NORMAL = 0,
  68         RENAME_DELETE,
  69         RENAME_ONE_FILE_TO_TWO
  70 };
  71
  72 struct rename_df_conflict_info {
  73         enum rename_type rename_type;
  74         struct diff_filepair *pair1;
  75         struct diff_filepair *pair2;
  76         const char *branch1;
  77         const char *branch2;
  78         struct stage_data *dst_entry1;
  79         struct stage_data *dst_entry2;
  80 };
  81
  82 /*
  83  * Since we want to write the index eventually, we cannot reuse the index
  84  * for these (temporary) data.
  85  */
  86 struct stage_data {
  87         struct {
  88                 unsigned mode;
  89                 unsigned char sha[20];
  90         } stages[4];
  91         struct rename_df_conflict_info *rename_df_conflict_info;
  92         unsigned processed:1;
  93 };
  94
  95 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
  96                                                  struct diff_filepair *pair1,
  97                                                  struct diff_filepair *pair2,
  98                                                  const char *branch1,
  99                                                  const char *branch2,
 100                                                  struct stage_data *dst_entry1,
 101                                                  struct stage_data *dst_entry2)
 102 {
 103         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
 104         ci->rename_type = rename_type;
 105         ci->pair1 = pair1;
 106         ci->branch1 = branch1;
 107         ci->branch2 = branch2;
 108
 109         ci->dst_entry1 = dst_entry1;
 110         dst_entry1->rename_df_conflict_info = ci;
 111         dst_entry1->processed = 0;
 112
 113         assert(!pair2 == !dst_entry2);
 114         if (dst_entry2) {
 115                 ci->dst_entry2 = dst_entry2;
 116                 ci->pair2 = pair2;
 117                 dst_entry2->rename_df_conflict_info = ci;
 118                 dst_entry2->processed = 0;
 119         }
 120 }
 121
 122 static int show(struct merge_options *o, int v)
 123 {
 124         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 125 }
 126
 127 static void flush_output(struct merge_options *o)
 128 {
 129         if (o->obuf.len) {
 130                 fputs(o->obuf.buf, stdout);
 131                 strbuf_reset(&o->obuf);
 132         }
 133 }
 134
 135 __attribute__((format (printf, 3, 4)))
 136 static void output(struct merge_options *o, int v, const char *fmt, ...)
 137 {
 138         va_list ap;
 139
 140         if (!show(o, v))
 141                 return;
 142
 143         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 144         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 145         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 146
 147         va_start(ap, fmt);
 148         strbuf_vaddf(&o->obuf, fmt, ap);
 149         va_end(ap);
 150
 151         strbuf_add(&o->obuf, "\n", 1);
 152         if (!o->buffer_output)
 153                 flush_output(o);
 154 }
 155
 156 static void output_commit_title(struct merge_options *o, struct commit *commit)
 157 {
 158         int i;
 159         flush_output(o);
 160         for (i = o->call_depth; i--;)
 161                 fputs("  ", stdout);
 162         if (commit->util)
 163                 printf("virtual %s\n", (char *)commit->util);
 164         else {
 165                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 166                 if (parse_commit(commit) != 0)
 167                         printf("(bad commit)\n");
 168                 else {
 169                         const char *title;
 170                         int len = find_commit_subject(commit->buffer, &title);
 171                         if (len)
 172                                 printf("%.*s\n", len, title);
 173                 }
 174         }
 175 }
 176
 177 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 178                 const char *path, int stage, int refresh, int options)
 179 {
 180         struct cache_entry *ce;
 181         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 182         if (!ce)
 183                 return error("addinfo_cache failed for path '%s'", path);
 184         return add_cache_entry(ce, options);
 185 }
 186
 187 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 188 {
 189         parse_tree(tree);
 190         init_tree_desc(desc, tree->buffer, tree->size);
 191 }
 192
 193 static int git_merge_trees(int index_only,
 194                            struct tree *common,
 195                            struct tree *head,
 196                            struct tree *merge)
 197 {
 198         int rc;
 199         struct tree_desc t[3];
 200         struct unpack_trees_options opts;
 201
 202         memset(&opts, 0, sizeof(opts));
 203         if (index_only)
 204                 opts.index_only = 1;
 205         else
 206                 opts.update = 1;
 207         opts.merge = 1;
 208         opts.head_idx = 2;
 209         opts.fn = threeway_merge;
 210         opts.src_index = &the_index;
 211         opts.dst_index = &the_index;
 212         setup_unpack_trees_porcelain(&opts, "merge");
 213
 214         init_tree_desc_from_tree(t+0, common);
 215         init_tree_desc_from_tree(t+1, head);
 216         init_tree_desc_from_tree(t+2, merge);
 217
 218         rc = unpack_trees(3, t, &opts);
 219         cache_tree_free(&active_cache_tree);
 220         return rc;
 221 }
 222
 223 struct tree *write_tree_from_memory(struct merge_options *o)
 224 {
 225         struct tree *result = NULL;
 226
 227         if (unmerged_cache()) {
 228                 int i;
 229                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 230                 for (i = 0; i < active_nr; i++) {
 231                         struct cache_entry *ce = active_cache[i];
 232                         if (ce_stage(ce))
 233                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 234                                         (int)ce_namelen(ce), ce->name);
 235                 }
 236                 die("Bug in merge-recursive.c");
 237         }
 238
 239         if (!active_cache_tree)
 240                 active_cache_tree = cache_tree();
 241
 242         if (!cache_tree_fully_valid(active_cache_tree) &&
 243             cache_tree_update(active_cache_tree,
 244                               active_cache, active_nr, 0, 0) < 0)
 245                 die("error building trees");
 246
 247         result = lookup_tree(active_cache_tree->sha1);
 248
 249         return result;
 250 }
 251
 252 static int save_files_dirs(const unsigned char *sha1,
 253                 const char *base, int baselen, const char *path,
 254                 unsigned int mode, int stage, void *context)
 255 {
 256         int len = strlen(path);
 257         char *newpath = xmalloc(baselen + len + 1);
 258         struct merge_options *o = context;
 259
 260         memcpy(newpath, base, baselen);
 261         memcpy(newpath + baselen, path, len);
 262         newpath[baselen + len] = '\0';
 263
 264         if (S_ISDIR(mode))
 265                 string_list_insert(&o->current_directory_set, newpath);
 266         else
 267                 string_list_insert(&o->current_file_set, newpath);
 268         free(newpath);
 269
 270         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 271 }
 272
 273 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 274 {
 275         int n;
 276         struct pathspec match_all;
 277         init_pathspec(&match_all, NULL);
 278         if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
 279                 return 0;
 280         n = o->current_file_set.nr + o->current_directory_set.nr;
 281         return n;
 282 }
 283
 284 /*
 285  * Returns an index_entry instance which doesn't have to correspond to
 286  * a real cache entry in Git's index.
 287  */
 288 static struct stage_data *insert_stage_data(const char *path,
 289                 struct tree *o, struct tree *a, struct tree *b,
 290                 struct string_list *entries)
 291 {
 292         struct string_list_item *item;
 293         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 294         get_tree_entry(o->object.sha1, path,
 295                         e->stages[1].sha, &e->stages[1].mode);
 296         get_tree_entry(a->object.sha1, path,
 297                         e->stages[2].sha, &e->stages[2].mode);
 298         get_tree_entry(b->object.sha1, path,
 299                         e->stages[3].sha, &e->stages[3].mode);
 300         item = string_list_insert(entries, path);
 301         item->util = e;
 302         return e;
 303 }
 304
 305 /*
 306  * Create a dictionary mapping file names to stage_data objects. The
 307  * dictionary contains one entry for every path with a non-zero stage entry.
 308  */
 309 static struct string_list *get_unmerged(void)
 310 {
 311         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 312         int i;
 313
 314         unmerged->strdup_strings = 1;
 315
 316         for (i = 0; i < active_nr; i++) {
 317                 struct string_list_item *item;
 318                 struct stage_data *e;
 319                 struct cache_entry *ce = active_cache[i];
 320                 if (!ce_stage(ce))
 321                         continue;
 322
 323                 item = string_list_lookup(unmerged, ce->name);
 324                 if (!item) {
 325                         item = string_list_insert(unmerged, ce->name);
 326                         item->util = xcalloc(1, sizeof(struct stage_data));
 327                 }
 328                 e = item->util;
 329                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 330                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 331         }
 332
 333         return unmerged;
 334 }
 335
 336 static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
 337                                                       struct string_list *entries)
 338 {
 339         /* If there are D/F conflicts, and the paths currently exist
 340          * in the working copy as a file, we want to remove them to
 341          * make room for the corresponding directory.  Such paths will
 342          * later be processed in process_df_entry() at the end.  If
 343          * the corresponding directory ends up being removed by the
 344          * merge, then the file will be reinstated at that time
 345          * (albeit with a different timestamp!); otherwise, if the
 346          * file is not supposed to be removed by the merge, the
 347          * contents of the file will be placed in another unique
 348          * filename.
 349          *
 350          * NOTE: This function relies on the fact that entries for a
 351          * D/F conflict will appear adjacent in the index, with the
 352          * entries for the file appearing before entries for paths
 353          * below the corresponding directory.
 354          */
 355         const char *last_file = NULL;
 356         int last_len = 0;
 357         int i;
 358
 359         /*
 360          * Do not do any of this crazyness during the recursive; we don't
 361          * even write anything to the working tree!
 362          */
 363         if (o->call_depth)
 364                 return;
 365
 366         for (i = 0; i < entries->nr; i++) {
 367                 const char *path = entries->items[i].string;
 368                 int len = strlen(path);
 369                 struct stage_data *e = entries->items[i].util;
 370
 371                 /*
 372                  * Check if last_file & path correspond to a D/F conflict;
 373                  * i.e. whether path is last_file+'/'+<something>.
 374                  * If so, remove last_file to make room for path and friends.
 375                  */
 376                 if (last_file &&
 377                     len > last_len &&
 378                     memcmp(path, last_file, last_len) == 0 &&
 379                     path[last_len] == '/') {
 380                         output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
 381                         unlink(last_file);
 382                 }
 383
 384                 /*
 385                  * Determine whether path could exist as a file in the
 386                  * working directory as a possible D/F conflict.  This
 387                  * will only occur when it exists in stage 2 as a
 388                  * file.
 389                  */
 390                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 391                         last_file = path;
 392                         last_len = len;
 393                 } else {
 394                         last_file = NULL;
 395                 }
 396         }
 397 }
 398
 399 struct rename {
 400         struct diff_filepair *pair;
 401         struct stage_data *src_entry;
 402         struct stage_data *dst_entry;
 403         unsigned processed:1;
 404 };
 405
 406 /*
 407  * Get information of all renames which occurred between 'o_tree' and
 408  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 409  * 'b_tree') to be able to associate the correct cache entries with
 410  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 411  */
 412 static struct string_list *get_renames(struct merge_options *o,
 413                                        struct tree *tree,
 414                                        struct tree *o_tree,
 415                                        struct tree *a_tree,
 416                                        struct tree *b_tree,
 417                                        struct string_list *entries)
 418 {
 419         int i;
 420         struct string_list *renames;
 421         struct diff_options opts;
 422
 423         renames = xcalloc(1, sizeof(struct string_list));
 424         diff_setup(&opts);
 425         DIFF_OPT_SET(&opts, RECURSIVE);
 426         opts.detect_rename = DIFF_DETECT_RENAME;
 427         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 428                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 429                             1000;
 430         opts.rename_score = o->rename_score;
 431         opts.show_rename_progress = o->show_rename_progress;
 432         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 433         if (diff_setup_done(&opts) < 0)
 434                 die("diff setup failed");
 435         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 436         diffcore_std(&opts);
 437         if (opts.needed_rename_limit > o->needed_rename_limit)
 438                 o->needed_rename_limit = opts.needed_rename_limit;
 439         for (i = 0; i < diff_queued_diff.nr; ++i) {
 440                 struct string_list_item *item;
 441                 struct rename *re;
 442                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 443                 if (pair->status != 'R') {
 444                         diff_free_filepair(pair);
 445                         continue;
 446                 }
 447                 re = xmalloc(sizeof(*re));
 448                 re->processed = 0;
 449                 re->pair = pair;
 450                 item = string_list_lookup(entries, re->pair->one->path);
 451                 if (!item)
 452                         re->src_entry = insert_stage_data(re->pair->one->path,
 453                                         o_tree, a_tree, b_tree, entries);
 454                 else
 455                         re->src_entry = item->util;
 456
 457                 item = string_list_lookup(entries, re->pair->two->path);
 458                 if (!item)
 459                         re->dst_entry = insert_stage_data(re->pair->two->path,
 460                                         o_tree, a_tree, b_tree, entries);
 461                 else
 462                         re->dst_entry = item->util;
 463                 item = string_list_insert(renames, pair->one->path);
 464                 item->util = re;
 465         }
 466         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 467         diff_queued_diff.nr = 0;
 468         diff_flush(&opts);
 469         return renames;
 470 }
 471
 472 static int update_stages_options(const char *path, struct diff_filespec *o,
 473                          struct diff_filespec *a, struct diff_filespec *b,
 474                          int clear, int options)
 475 {
 476         if (clear)
 477                 if (remove_file_from_cache(path))
 478                         return -1;
 479         if (o)
 480                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 481                         return -1;
 482         if (a)
 483                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 484                         return -1;
 485         if (b)
 486                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 487                         return -1;
 488         return 0;
 489 }
 490
 491 static int update_stages(const char *path, struct diff_filespec *o,
 492                          struct diff_filespec *a, struct diff_filespec *b,
 493                          int clear)
 494 {
 495         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 496         return update_stages_options(path, o, a, b, clear, options);
 497 }
 498
 499 static int update_stages_and_entry(const char *path,
 500                                    struct stage_data *entry,
 501                                    struct diff_filespec *o,
 502                                    struct diff_filespec *a,
 503                                    struct diff_filespec *b,
 504                                    int clear)
 505 {
 506         int options;
 507
 508         entry->processed = 0;
 509         entry->stages[1].mode = o->mode;
 510         entry->stages[2].mode = a->mode;
 511         entry->stages[3].mode = b->mode;
 512         hashcpy(entry->stages[1].sha, o->sha1);
 513         hashcpy(entry->stages[2].sha, a->sha1);
 514         hashcpy(entry->stages[3].sha, b->sha1);
 515         options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 516         return update_stages_options(path, o, a, b, clear, options);
 517 }
 518
 519 static int remove_file(struct merge_options *o, int clean,
 520                        const char *path, int no_wd)
 521 {
 522         int update_cache = o->call_depth || clean;
 523         int update_working_directory = !o->call_depth && !no_wd;
 524
 525         if (update_cache) {
 526                 if (remove_file_from_cache(path))
 527                         return -1;
 528         }
 529         if (update_working_directory) {
 530                 if (remove_path(path))
 531                         return -1;
 532         }
 533         return 0;
 534 }
 535
 536 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 537 {
 538         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 539         int suffix = 0;
 540         struct stat st;
 541         char *p = newpath + strlen(path);
 542         strcpy(newpath, path);
 543         *(p++) = '~';
 544         strcpy(p, branch);
 545         for (; *p; ++p)
 546                 if ('/' == *p)
 547                         *p = '_';
 548         while (string_list_has_string(&o->current_file_set, newpath) ||
 549                string_list_has_string(&o->current_directory_set, newpath) ||
 550                lstat(newpath, &st) == 0)
 551                 sprintf(p, "_%d", suffix++);
 552
 553         string_list_insert(&o->current_file_set, newpath);
 554         return newpath;
 555 }
 556
 557 static void flush_buffer(int fd, const char *buf, unsigned long size)
 558 {
 559         while (size > 0) {
 560                 long ret = write_in_full(fd, buf, size);
 561                 if (ret < 0) {
 562                         /* Ignore epipe */
 563                         if (errno == EPIPE)
 564                                 break;
 565                         die_errno("merge-recursive");
 566                 } else if (!ret) {
 567                         die("merge-recursive: disk full?");
 568                 }
 569                 size -= ret;
 570                 buf += ret;
 571         }
 572 }
 573
 574 static int would_lose_untracked(const char *path)
 575 {
 576         int pos = cache_name_pos(path, strlen(path));
 577
 578         if (pos < 0)
 579                 pos = -1 - pos;
 580         while (pos < active_nr &&
 581                !strcmp(path, active_cache[pos]->name)) {
 582                 /*
 583                  * If stage #0, it is definitely tracked.
 584                  * If it has stage #2 then it was tracked
 585                  * before this merge started.  All other
 586                  * cases the path was not tracked.
 587                  */
 588                 switch (ce_stage(active_cache[pos])) {
 589                 case 0:
 590                 case 2:
 591                         return 0;
 592                 }
 593                 pos++;
 594         }
 595         return file_exists(path);
 596 }
 597
 598 static int make_room_for_path(const char *path)
 599 {
 600         int status;
 601         const char *msg = "failed to create path '%s'%s";
 602
 603         status = safe_create_leading_directories_const(path);
 604         if (status) {
 605                 if (status == -3) {
 606                         /* something else exists */
 607                         error(msg, path, ": perhaps a D/F conflict?");
 608                         return -1;
 609                 }
 610                 die(msg, path, "");
 611         }
 612
 613         /*
 614          * Do not unlink a file in the work tree if we are not
 615          * tracking it.
 616          */
 617         if (would_lose_untracked(path))
 618                 return error("refusing to lose untracked file at '%s'",
 619                              path);
 620
 621         /* Successful unlink is good.. */
 622         if (!unlink(path))
 623                 return 0;
 624         /* .. and so is no existing file */
 625         if (errno == ENOENT)
 626                 return 0;
 627         /* .. but not some other error (who really cares what?) */
 628         return error(msg, path, ": perhaps a D/F conflict?");
 629 }
 630
 631 static void update_file_flags(struct merge_options *o,
 632                               const unsigned char *sha,
 633                               unsigned mode,
 634                               const char *path,
 635                               int update_cache,
 636                               int update_wd)
 637 {
 638         if (o->call_depth)
 639                 update_wd = 0;
 640
 641         if (update_wd) {
 642                 enum object_type type;
 643                 void *buf;
 644                 unsigned long size;
 645
 646                 if (S_ISGITLINK(mode)) {
 647                         /*
 648                          * We may later decide to recursively descend into
 649                          * the submodule directory and update its index
 650                          * and/or work tree, but we do not do that now.
 651                          */
 652                         update_wd = 0;
 653                         goto update_index;
 654                 }
 655
 656                 buf = read_sha1_file(sha, &type, &size);
 657                 if (!buf)
 658                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 659                 if (type != OBJ_BLOB)
 660                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 661                 if (S_ISREG(mode)) {
 662                         struct strbuf strbuf = STRBUF_INIT;
 663                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 664                                 free(buf);
 665                                 size = strbuf.len;
 666                                 buf = strbuf_detach(&strbuf, NULL);
 667                         }
 668                 }
 669
 670                 if (make_room_for_path(path) < 0) {
 671                         update_wd = 0;
 672                         free(buf);
 673                         goto update_index;
 674                 }
 675                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 676                         int fd;
 677                         if (mode & 0100)
 678                                 mode = 0777;
 679                         else
 680                                 mode = 0666;
 681                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 682                         if (fd < 0)
 683                                 die_errno("failed to open '%s'", path);
 684                         flush_buffer(fd, buf, size);
 685                         close(fd);
 686                 } else if (S_ISLNK(mode)) {
 687                         char *lnk = xmemdupz(buf, size);
 688                         safe_create_leading_directories_const(path);
 689                         unlink(path);
 690                         if (symlink(lnk, path))
 691                                 die_errno("failed to symlink '%s'", path);
 692                         free(lnk);
 693                 } else
 694                         die("do not know what to do with %06o %s '%s'",
 695                             mode, sha1_to_hex(sha), path);
 696                 free(buf);
 697         }
 698  update_index:
 699         if (update_cache)
 700                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 701 }
 702
 703 static void update_file(struct merge_options *o,
 704                         int clean,
 705                         const unsigned char *sha,
 706                         unsigned mode,
 707                         const char *path)
 708 {
 709         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 710 }
 711
 712 /* Low level file merging, update and removal */
 713
 714 struct merge_file_info {
 715         unsigned char sha[20];
 716         unsigned mode;
 717         unsigned clean:1,
 718                  merge:1;
 719 };
 720
 721 static int merge_3way(struct merge_options *o,
 722                       mmbuffer_t *result_buf,
 723                       struct diff_filespec *one,
 724                       struct diff_filespec *a,
 725                       struct diff_filespec *b,
 726                       const char *branch1,
 727                       const char *branch2)
 728 {
 729         mmfile_t orig, src1, src2;
 730         struct ll_merge_options ll_opts = {0};
 731         char *base_name, *name1, *name2;
 732         int merge_status;
 733
 734         ll_opts.renormalize = o->renormalize;
 735         ll_opts.xdl_opts = o->xdl_opts;
 736
 737         if (o->call_depth) {
 738                 ll_opts.virtual_ancestor = 1;
 739                 ll_opts.variant = 0;
 740         } else {
 741                 switch (o->recursive_variant) {
 742                 case MERGE_RECURSIVE_OURS:
 743                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 744                         break;
 745                 case MERGE_RECURSIVE_THEIRS:
 746                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 747                         break;
 748                 default:
 749                         ll_opts.variant = 0;
 750                         break;
 751                 }
 752         }
 753
 754         if (strcmp(a->path, b->path) ||
 755             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 756                 base_name = o->ancestor == NULL ? NULL :
 757                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 758                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 759                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 760         } else {
 761                 base_name = o->ancestor == NULL ? NULL :
 762                         xstrdup(mkpath("%s", o->ancestor));
 763                 name1 = xstrdup(mkpath("%s", branch1));
 764                 name2 = xstrdup(mkpath("%s", branch2));
 765         }
 766
 767         read_mmblob(&orig, one->sha1);
 768         read_mmblob(&src1, a->sha1);
 769         read_mmblob(&src2, b->sha1);
 770
 771         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 772                                 &src1, name1, &src2, name2, &ll_opts);
 773
 774         free(name1);
 775         free(name2);
 776         free(orig.ptr);
 777         free(src1.ptr);
 778         free(src2.ptr);
 779         return merge_status;
 780 }
 781
 782 static struct merge_file_info merge_file(struct merge_options *o,
 783                                          struct diff_filespec *one,
 784                                          struct diff_filespec *a,
 785                                          struct diff_filespec *b,
 786                                          const char *branch1,
 787                                          const char *branch2)
 788 {
 789         struct merge_file_info result;
 790         result.merge = 0;
 791         result.clean = 1;
 792
 793         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 794                 result.clean = 0;
 795                 if (S_ISREG(a->mode)) {
 796                         result.mode = a->mode;
 797                         hashcpy(result.sha, a->sha1);
 798                 } else {
 799                         result.mode = b->mode;
 800                         hashcpy(result.sha, b->sha1);
 801                 }
 802         } else {
 803                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 804                         result.merge = 1;
 805
 806                 /*
 807                  * Merge modes
 808                  */
 809                 if (a->mode == b->mode || a->mode == one->mode)
 810                         result.mode = b->mode;
 811                 else {
 812                         result.mode = a->mode;
 813                         if (b->mode != one->mode) {
 814                                 result.clean = 0;
 815                                 result.merge = 1;
 816                         }
 817                 }
 818
 819                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 820                         hashcpy(result.sha, b->sha1);
 821                 else if (sha_eq(b->sha1, one->sha1))
 822                         hashcpy(result.sha, a->sha1);
 823                 else if (S_ISREG(a->mode)) {
 824                         mmbuffer_t result_buf;
 825                         int merge_status;
 826
 827                         merge_status = merge_3way(o, &result_buf, one, a, b,
 828                                                   branch1, branch2);
 829
 830                         if ((merge_status < 0) || !result_buf.ptr)
 831                                 die("Failed to execute internal merge");
 832
 833                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 834                                             blob_type, result.sha))
 835                                 die("Unable to add %s to database",
 836                                     a->path);
 837
 838                         free(result_buf.ptr);
 839                         result.clean = (merge_status == 0);
 840                 } else if (S_ISGITLINK(a->mode)) {
 841                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 842                                                        a->sha1, b->sha1);
 843                 } else if (S_ISLNK(a->mode)) {
 844                         hashcpy(result.sha, a->sha1);
 845
 846                         if (!sha_eq(a->sha1, b->sha1))
 847                                 result.clean = 0;
 848                 } else {
 849                         die("unsupported object type in the tree");
 850                 }
 851         }
 852
 853         return result;
 854 }
 855
 856 static void conflict_rename_delete(struct merge_options *o,
 857                                    struct diff_filepair *pair,
 858                                    const char *rename_branch,
 859                                    const char *other_branch)
 860 {
 861         char *dest_name = pair->two->path;
 862         int df_conflict = 0;
 863         struct stat st;
 864
 865         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 866                "and deleted in %s",
 867                pair->one->path, pair->two->path, rename_branch,
 868                other_branch);
 869         if (!o->call_depth)
 870                 update_stages(dest_name, NULL,
 871                               rename_branch == o->branch1 ? pair->two : NULL,
 872                               rename_branch == o->branch1 ? NULL : pair->two,
 873                               1);
 874         if (lstat(dest_name, &st) == 0 && S_ISDIR(st.st_mode)) {
 875                 dest_name = unique_path(o, dest_name, rename_branch);
 876                 df_conflict = 1;
 877         }
 878         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 879         if (df_conflict)
 880                 free(dest_name);
 881 }
 882
 883 static void conflict_rename_rename_1to2(struct merge_options *o,
 884                                         struct diff_filepair *pair1,
 885                                         const char *branch1,
 886                                         struct diff_filepair *pair2,
 887                                         const char *branch2)
 888 {
 889         /* One file was renamed in both branches, but to different names. */
 890         char *del[2];
 891         int delp = 0;
 892         const char *ren1_dst = pair1->two->path;
 893         const char *ren2_dst = pair2->two->path;
 894         const char *dst_name1 = ren1_dst;
 895         const char *dst_name2 = ren2_dst;
 896         struct stat st;
 897         if (lstat(ren1_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 898                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 899                 output(o, 1, "%s is a directory in %s adding as %s instead",
 900                        ren1_dst, branch2, dst_name1);
 901         }
 902         if (lstat(ren2_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 903                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 904                 output(o, 1, "%s is a directory in %s adding as %s instead",
 905                        ren2_dst, branch1, dst_name2);
 906         }
 907         if (o->call_depth) {
 908                 remove_file_from_cache(dst_name1);
 909                 remove_file_from_cache(dst_name2);
 910                 /*
 911                  * Uncomment to leave the conflicting names in the resulting tree
 912                  *
 913                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 914                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 915                  */
 916         } else {
 917                 update_stages(ren1_dst, NULL, pair1->two, NULL, 1);
 918                 update_stages(ren2_dst, NULL, NULL, pair2->two, 1);
 919
 920                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 921                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 922         }
 923         while (delp--)
 924                 free(del[delp]);
 925 }
 926
 927 static void conflict_rename_rename_2to1(struct merge_options *o,
 928                                         struct rename *ren1,
 929                                         const char *branch1,
 930                                         struct rename *ren2,
 931                                         const char *branch2)
 932 {
 933         /* Two files were renamed to the same thing. */
 934         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 935         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 936         output(o, 1, "Renaming %s to %s and %s to %s instead",
 937                ren1->pair->one->path, new_path1,
 938                ren2->pair->one->path, new_path2);
 939         remove_file(o, 0, ren1->pair->two->path, 0);
 940         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 941         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 942         free(new_path2);
 943         free(new_path1);
 944 }
 945
 946 static int process_renames(struct merge_options *o,
 947                            struct string_list *a_renames,
 948                            struct string_list *b_renames)
 949 {
 950         int clean_merge = 1, i, j;
 951         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 952         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 953         const struct rename *sre;
 954
 955         for (i = 0; i < a_renames->nr; i++) {
 956                 sre = a_renames->items[i].util;
 957                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 958                         = sre->dst_entry;
 959         }
 960         for (i = 0; i < b_renames->nr; i++) {
 961                 sre = b_renames->items[i].util;
 962                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 963                         = sre->dst_entry;
 964         }
 965
 966         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 967                 struct string_list *renames1, *renames2Dst;
 968                 struct rename *ren1 = NULL, *ren2 = NULL;
 969                 const char *branch1, *branch2;
 970                 const char *ren1_src, *ren1_dst;
 971
 972                 if (i >= a_renames->nr) {
 973                         ren2 = b_renames->items[j++].util;
 974                 } else if (j >= b_renames->nr) {
 975                         ren1 = a_renames->items[i++].util;
 976                 } else {
 977                         int compare = strcmp(a_renames->items[i].string,
 978                                              b_renames->items[j].string);
 979                         if (compare <= 0)
 980                                 ren1 = a_renames->items[i++].util;
 981                         if (compare >= 0)
 982                                 ren2 = b_renames->items[j++].util;
 983                 }
 984
 985                 /* TODO: refactor, so that 1/2 are not needed */
 986                 if (ren1) {
 987                         renames1 = a_renames;
 988                         renames2Dst = &b_by_dst;
 989                         branch1 = o->branch1;
 990                         branch2 = o->branch2;
 991                 } else {
 992                         struct rename *tmp;
 993                         renames1 = b_renames;
 994                         renames2Dst = &a_by_dst;
 995                         branch1 = o->branch2;
 996                         branch2 = o->branch1;
 997                         tmp = ren2;
 998                         ren2 = ren1;
 999                         ren1 = tmp;
1000                 }
1001
1002                 ren1->dst_entry->processed = 1;
1003                 ren1->src_entry->processed = 1;
1004
1005                 if (ren1->processed)
1006                         continue;
1007                 ren1->processed = 1;
1008
1009                 ren1_src = ren1->pair->one->path;
1010                 ren1_dst = ren1->pair->two->path;
1011
1012                 if (ren2) {
1013                         const char *ren2_src = ren2->pair->one->path;
1014                         const char *ren2_dst = ren2->pair->two->path;
1015                         /* Renamed in 1 and renamed in 2 */
1016                         if (strcmp(ren1_src, ren2_src) != 0)
1017                                 die("ren1.src != ren2.src");
1018                         ren2->dst_entry->processed = 1;
1019                         ren2->processed = 1;
1020                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1021                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
1022                                                               ren1->pair,
1023                                                               ren2->pair,
1024                                                               branch1,
1025                                                               branch2,
1026                                                               ren1->dst_entry,
1027                                                               ren2->dst_entry);
1028                         } else {
1029                                 remove_file(o, 1, ren1_src, 1);
1030                                 update_stages_and_entry(ren1_dst,
1031                                                         ren1->dst_entry,
1032                                                         ren1->pair->one,
1033                                                         ren1->pair->two,
1034                                                         ren2->pair->two,
1035                                                         1 /* clear */);
1036                         }
1037                 } else {
1038                         /* Renamed in 1, maybe changed in 2 */
1039                         struct string_list_item *item;
1040                         /* we only use sha1 and mode of these */
1041                         struct diff_filespec src_other, dst_other;
1042                         int try_merge;
1043
1044                         /*
1045                          * unpack_trees loads entries from common-commit
1046                          * into stage 1, from head-commit into stage 2, and
1047                          * from merge-commit into stage 3.  We keep track
1048                          * of which side corresponds to the rename.
1049                          */
1050                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1051                         int other_stage =   a_renames == renames1 ? 3 : 2;
1052
1053                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
1054
1055                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1056                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1057                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1058                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1059                         try_merge = 0;
1060
1061                         if (sha_eq(src_other.sha1, null_sha1)) {
1062                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1063                                         ren1->dst_entry->processed = 0;
1064                                         setup_rename_df_conflict_info(RENAME_DELETE,
1065                                                                       ren1->pair,
1066                                                                       NULL,
1067                                                                       branch1,
1068                                                                       branch2,
1069                                                                       ren1->dst_entry,
1070                                                                       NULL);
1071                                 } else {
1072                                         clean_merge = 0;
1073                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1074                                 }
1075                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1076                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1077                                 /* Added file on the other side
1078                                    identical to the file being
1079                                    renamed: clean merge */
1080                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1081                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1082                                 const char *new_path;
1083                                 clean_merge = 0;
1084                                 try_merge = 1;
1085                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1086                                        "%s added in %s",
1087                                        ren1_src, ren1_dst, branch1,
1088                                        ren1_dst, branch2);
1089                                 if (o->call_depth) {
1090                                         struct merge_file_info mfi;
1091                                         struct diff_filespec one, a, b;
1092
1093                                         one.path = a.path = b.path =
1094                                                 (char *)ren1_dst;
1095                                         hashcpy(one.sha1, null_sha1);
1096                                         one.mode = 0;
1097                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1098                                         a.mode = ren1->pair->two->mode;
1099                                         hashcpy(b.sha1, dst_other.sha1);
1100                                         b.mode = dst_other.mode;
1101                                         mfi = merge_file(o, &one, &a, &b,
1102                                                          branch1,
1103                                                          branch2);
1104                                         output(o, 1, "Adding merged %s", ren1_dst);
1105                                         update_file(o, 0,
1106                                                     mfi.sha,
1107                                                     mfi.mode,
1108                                                     ren1_dst);
1109                                         try_merge = 0;
1110                                 } else {
1111                                         new_path = unique_path(o, ren1_dst, branch2);
1112                                         output(o, 1, "Adding as %s instead", new_path);
1113                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1114                                 }
1115                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1116                                 ren2 = item->util;
1117                                 clean_merge = 0;
1118                                 ren2->processed = 1;
1119                                 output(o, 1, "CONFLICT (rename/rename): "
1120                                        "Rename %s->%s in %s. "
1121                                        "Rename %s->%s in %s",
1122                                        ren1_src, ren1_dst, branch1,
1123                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1124                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1125                         } else
1126                                 try_merge = 1;
1127
1128                         if (try_merge) {
1129                                 struct diff_filespec *one, *a, *b;
1130                                 src_other.path = (char *)ren1_src;
1131
1132                                 one = ren1->pair->one;
1133                                 if (a_renames == renames1) {
1134                                         a = ren1->pair->two;
1135                                         b = &src_other;
1136                                 } else {
1137                                         b = ren1->pair->two;
1138                                         a = &src_other;
1139                                 }
1140                                 update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
1141                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1142                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1143                                                                       ren1->pair,
1144                                                                       NULL,
1145                                                                       branch1,
1146                                                                       NULL,
1147                                                                       ren1->dst_entry,
1148                                                                       NULL);
1149                                 }
1150                         }
1151                 }
1152         }
1153         string_list_clear(&a_by_dst, 0);
1154         string_list_clear(&b_by_dst, 0);
1155
1156         return clean_merge;
1157 }
1158
1159 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1160 {
1161         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1162 }
1163
1164 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1165 {
1166         void *buf;
1167         enum object_type type;
1168         unsigned long size;
1169         buf = read_sha1_file(sha1, &type, &size);
1170         if (!buf)
1171                 return error("cannot read object %s", sha1_to_hex(sha1));
1172         if (type != OBJ_BLOB) {
1173                 free(buf);
1174                 return error("object %s is not a blob", sha1_to_hex(sha1));
1175         }
1176         strbuf_attach(dst, buf, size, size + 1);
1177         return 0;
1178 }
1179
1180 static int blob_unchanged(const unsigned char *o_sha,
1181                           const unsigned char *a_sha,
1182                           int renormalize, const char *path)
1183 {
1184         struct strbuf o = STRBUF_INIT;
1185         struct strbuf a = STRBUF_INIT;
1186         int ret = 0; /* assume changed for safety */
1187
1188         if (sha_eq(o_sha, a_sha))
1189                 return 1;
1190         if (!renormalize)
1191                 return 0;
1192
1193         assert(o_sha && a_sha);
1194         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1195                 goto error_return;
1196         /*
1197          * Note: binary | is used so that both renormalizations are
1198          * performed.  Comparison can be skipped if both files are
1199          * unchanged since their sha1s have already been compared.
1200          */
1201         if (renormalize_buffer(path, o.buf, o.len, &o) |
1202             renormalize_buffer(path, a.buf, o.len, &a))
1203                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1204
1205 error_return:
1206         strbuf_release(&o);
1207         strbuf_release(&a);
1208         return ret;
1209 }
1210
1211 static void handle_delete_modify(struct merge_options *o,
1212                                  const char *path,
1213                                  const char *new_path,
1214                                  unsigned char *a_sha, int a_mode,
1215                                  unsigned char *b_sha, int b_mode)
1216 {
1217         if (!a_sha) {
1218                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1219                        "and modified in %s. Version %s of %s left in tree%s%s.",
1220                        path, o->branch1,
1221                        o->branch2, o->branch2, path,
1222                        path == new_path ? "" : " at ",
1223                        path == new_path ? "" : new_path);
1224                 update_file(o, 0, b_sha, b_mode, new_path);
1225         } else {
1226                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1227                        "and modified in %s. Version %s of %s left in tree%s%s.",
1228                        path, o->branch2,
1229                        o->branch1, o->branch1, path,
1230                        path == new_path ? "" : " at ",
1231                        path == new_path ? "" : new_path);
1232                 update_file(o, 0, a_sha, a_mode, new_path);
1233         }
1234 }
1235
1236 static int merge_content(struct merge_options *o,
1237                          const char *path,
1238                          unsigned char *o_sha, int o_mode,
1239                          unsigned char *a_sha, int a_mode,
1240                          unsigned char *b_sha, int b_mode,
1241                          const char *df_rename_conflict_branch)
1242 {
1243         const char *reason = "content";
1244         struct merge_file_info mfi;
1245         struct diff_filespec one, a, b;
1246         struct stat st;
1247         unsigned df_conflict_remains = 0;
1248
1249         if (!o_sha) {
1250                 reason = "add/add";
1251                 o_sha = (unsigned char *)null_sha1;
1252         }
1253         one.path = a.path = b.path = (char *)path;
1254         hashcpy(one.sha1, o_sha);
1255         one.mode = o_mode;
1256         hashcpy(a.sha1, a_sha);
1257         a.mode = a_mode;
1258         hashcpy(b.sha1, b_sha);
1259         b.mode = b_mode;
1260
1261         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1262         if (df_rename_conflict_branch &&
1263             lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1264                 df_conflict_remains = 1;
1265         }
1266
1267         if (mfi.clean && !df_conflict_remains &&
1268             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode &&
1269             !o->call_depth && !lstat(path, &st)) {
1270                 output(o, 3, "Skipped %s (merged same as existing)", path);
1271                 add_cacheinfo(mfi.mode, mfi.sha, path,
1272                               0 /*stage*/, 1 /*refresh*/, 0 /*options*/);
1273                 return mfi.clean;
1274         } else
1275                 output(o, 2, "Auto-merging %s", path);
1276
1277         if (!mfi.clean) {
1278                 if (S_ISGITLINK(mfi.mode))
1279                         reason = "submodule";
1280                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1281                                 reason, path);
1282         }
1283
1284         if (df_conflict_remains) {
1285                 const char *new_path;
1286                 update_file_flags(o, mfi.sha, mfi.mode, path,
1287                                   o->call_depth || mfi.clean, 0);
1288                 new_path = unique_path(o, path, df_rename_conflict_branch);
1289                 mfi.clean = 0;
1290                 output(o, 1, "Adding as %s instead", new_path);
1291                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1292         } else {
1293                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1294         }
1295         return mfi.clean;
1296
1297 }
1298
1299 /* Per entry merge function */
1300 static int process_entry(struct merge_options *o,
1301                          const char *path, struct stage_data *entry)
1302 {
1303         /*
1304         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1305         print_index_entry("\tpath: ", entry);
1306         */
1307         int clean_merge = 1;
1308         int normalize = o->renormalize;
1309         unsigned o_mode = entry->stages[1].mode;
1310         unsigned a_mode = entry->stages[2].mode;
1311         unsigned b_mode = entry->stages[3].mode;
1312         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1313         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1314         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1315
1316         if (entry->rename_df_conflict_info)
1317                 return 1; /* Such cases are handled elsewhere. */
1318
1319         entry->processed = 1;
1320         if (o_sha && (!a_sha || !b_sha)) {
1321                 /* Case A: Deleted in one */
1322                 if ((!a_sha && !b_sha) ||
1323                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1324                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1325                         /* Deleted in both or deleted in one and
1326                          * unchanged in the other */
1327                         if (a_sha)
1328                                 output(o, 2, "Removing %s", path);
1329                         /* do not touch working file if it did not exist */
1330                         remove_file(o, 1, path, !a_sha);
1331                 } else if (string_list_has_string(&o->current_directory_set,
1332                                                   path)) {
1333                         entry->processed = 0;
1334                         return 1; /* Assume clean until processed */
1335                 } else {
1336                         /* Deleted in one and changed in the other */
1337                         clean_merge = 0;
1338                         handle_delete_modify(o, path, path,
1339                                              a_sha, a_mode, b_sha, b_mode);
1340                 }
1341
1342         } else if ((!o_sha && a_sha && !b_sha) ||
1343                    (!o_sha && !a_sha && b_sha)) {
1344                 /* Case B: Added in one. */
1345                 unsigned mode;
1346                 const unsigned char *sha;
1347
1348                 if (a_sha) {
1349                         mode = a_mode;
1350                         sha = a_sha;
1351                 } else {
1352                         mode = b_mode;
1353                         sha = b_sha;
1354                 }
1355                 if (string_list_has_string(&o->current_directory_set, path)) {
1356                         /* Handle D->F conflicts after all subfiles */
1357                         entry->processed = 0;
1358                         return 1; /* Assume clean until processed */
1359                 } else {
1360                         output(o, 2, "Adding %s", path);
1361                         update_file(o, 1, sha, mode, path);
1362                 }
1363         } else if (a_sha && b_sha) {
1364                 /* Case C: Added in both (check for same permissions) and */
1365                 /* case D: Modified in both, but differently. */
1366                 clean_merge = merge_content(o, path,
1367                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1368                                             NULL);
1369         } else if (!o_sha && !a_sha && !b_sha) {
1370                 /*
1371                  * this entry was deleted altogether. a_mode == 0 means
1372                  * we had that path and want to actively remove it.
1373                  */
1374                 remove_file(o, 1, path, !a_mode);
1375         } else
1376                 die("Fatal merge failure, shouldn't happen.");
1377
1378         return clean_merge;
1379 }
1380
1381 /*
1382  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1383  * cases we can cleanly resolve D/F conflicts, process_entry() can
1384  * clean out all the files below the directory for us.  All D/F
1385  * conflict cases must be handled here at the end to make sure any
1386  * directories that can be cleaned out, are.
1387  *
1388  * Some rename conflicts may also be handled here that don't necessarily
1389  * involve D/F conflicts, since the code to handle them is generic enough
1390  * to handle those rename conflicts with or without D/F conflicts also
1391  * being involved.
1392  */
1393 static int process_df_entry(struct merge_options *o,
1394                             const char *path, struct stage_data *entry)
1395 {
1396         int clean_merge = 1;
1397         unsigned o_mode = entry->stages[1].mode;
1398         unsigned a_mode = entry->stages[2].mode;
1399         unsigned b_mode = entry->stages[3].mode;
1400         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1401         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1402         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1403         struct stat st;
1404
1405         entry->processed = 1;
1406         if (entry->rename_df_conflict_info) {
1407                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1408                 char *src;
1409                 switch (conflict_info->rename_type) {
1410                 case RENAME_NORMAL:
1411                         clean_merge = merge_content(o, path,
1412                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1413                                                     conflict_info->branch1);
1414                         break;
1415                 case RENAME_DELETE:
1416                         clean_merge = 0;
1417                         conflict_rename_delete(o, conflict_info->pair1,
1418                                                conflict_info->branch1,
1419                                                conflict_info->branch2);
1420                         break;
1421                 case RENAME_ONE_FILE_TO_TWO:
1422                         src = conflict_info->pair1->one->path;
1423                         clean_merge = 0;
1424                         output(o, 1, "CONFLICT (rename/rename): "
1425                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1426                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1427                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1428                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1429                                o->call_depth ? " (left unresolved)" : "");
1430                         if (o->call_depth) {
1431                                 remove_file_from_cache(src);
1432                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1433                                             conflict_info->pair1->one->mode, src);
1434                         }
1435                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1436                                                     conflict_info->branch1,
1437                                                     conflict_info->pair2,
1438                                                     conflict_info->branch2);
1439                         conflict_info->dst_entry2->processed = 1;
1440                         break;
1441                 default:
1442                         entry->processed = 0;
1443                         break;
1444                 }
1445         } else if (o_sha && (!a_sha || !b_sha)) {
1446                 /* Modify/delete; deleted side may have put a directory in the way */
1447                 const char *new_path = path;
1448                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode))
1449                         new_path = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1450                 clean_merge = 0;
1451                 handle_delete_modify(o, path, new_path,
1452                                      a_sha, a_mode, b_sha, b_mode);
1453         } else if (!o_sha && !!a_sha != !!b_sha) {
1454                 /* directory -> (directory, file) */
1455                 const char *add_branch;
1456                 const char *other_branch;
1457                 unsigned mode;
1458                 const unsigned char *sha;
1459                 const char *conf;
1460
1461                 if (a_sha) {
1462                         add_branch = o->branch1;
1463                         other_branch = o->branch2;
1464                         mode = a_mode;
1465                         sha = a_sha;
1466                         conf = "file/directory";
1467                 } else {
1468                         add_branch = o->branch2;
1469                         other_branch = o->branch1;
1470                         mode = b_mode;
1471                         sha = b_sha;
1472                         conf = "directory/file";
1473                 }
1474                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1475                         const char *new_path = unique_path(o, path, add_branch);
1476                         clean_merge = 0;
1477                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1478                                "Adding %s as %s",
1479                                conf, path, other_branch, path, new_path);
1480                         update_file(o, 0, sha, mode, new_path);
1481                 } else {
1482                         output(o, 2, "Adding %s", path);
1483                         update_file(o, 1, sha, mode, path);
1484                 }
1485         } else {
1486                 entry->processed = 0;
1487                 return 1; /* not handled; assume clean until processed */
1488         }
1489
1490         return clean_merge;
1491 }
1492
1493 int merge_trees(struct merge_options *o,
1494                 struct tree *head,
1495                 struct tree *merge,
1496                 struct tree *common,
1497                 struct tree **result)
1498 {
1499         int code, clean;
1500
1501         if (o->subtree_shift) {
1502                 merge = shift_tree_object(head, merge, o->subtree_shift);
1503                 common = shift_tree_object(head, common, o->subtree_shift);
1504         }
1505
1506         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1507                 output(o, 0, "Already up-to-date!");
1508                 *result = head;
1509                 return 1;
1510         }
1511
1512         code = git_merge_trees(o->call_depth, common, head, merge);
1513
1514         if (code != 0) {
1515                 if (show(o, 4) || o->call_depth)
1516                         die("merging of trees %s and %s failed",
1517                             sha1_to_hex(head->object.sha1),
1518                             sha1_to_hex(merge->object.sha1));
1519                 else
1520                         exit(128);
1521         }
1522
1523         if (unmerged_cache()) {
1524                 struct string_list *entries, *re_head, *re_merge;
1525                 int i;
1526                 string_list_clear(&o->current_file_set, 1);
1527                 string_list_clear(&o->current_directory_set, 1);
1528                 get_files_dirs(o, head);
1529                 get_files_dirs(o, merge);
1530
1531                 entries = get_unmerged();
1532                 make_room_for_directories_of_df_conflicts(o, entries);
1533                 re_head  = get_renames(o, head, common, head, merge, entries);
1534                 re_merge = get_renames(o, merge, common, head, merge, entries);
1535                 clean = process_renames(o, re_head, re_merge);
1536                 for (i = 0; i < entries->nr; i++) {
1537                         const char *path = entries->items[i].string;
1538                         struct stage_data *e = entries->items[i].util;
1539                         if (!e->processed
1540                                 && !process_entry(o, path, e))
1541                                 clean = 0;
1542                 }
1543                 for (i = 0; i < entries->nr; i++) {
1544                         const char *path = entries->items[i].string;
1545                         struct stage_data *e = entries->items[i].util;
1546                         if (!e->processed
1547                                 && !process_df_entry(o, path, e))
1548                                 clean = 0;
1549                 }
1550                 for (i = 0; i < entries->nr; i++) {
1551                         struct stage_data *e = entries->items[i].util;
1552                         if (!e->processed)
1553                                 die("Unprocessed path??? %s",
1554                                     entries->items[i].string);
1555                 }
1556
1557                 string_list_clear(re_merge, 0);
1558                 string_list_clear(re_head, 0);
1559                 string_list_clear(entries, 1);
1560
1561         }
1562         else
1563                 clean = 1;
1564
1565         if (o->call_depth)
1566                 *result = write_tree_from_memory(o);
1567
1568         return clean;
1569 }
1570
1571 static struct commit_list *reverse_commit_list(struct commit_list *list)
1572 {
1573         struct commit_list *next = NULL, *current, *backup;
1574         for (current = list; current; current = backup) {
1575                 backup = current->next;
1576                 current->next = next;
1577                 next = current;
1578         }
1579         return next;
1580 }
1581
1582 /*
1583  * Merge the commits h1 and h2, return the resulting virtual
1584  * commit object and a flag indicating the cleanness of the merge.
1585  */
1586 int merge_recursive(struct merge_options *o,
1587                     struct commit *h1,
1588                     struct commit *h2,
1589                     struct commit_list *ca,
1590                     struct commit **result)
1591 {
1592         struct commit_list *iter;
1593         struct commit *merged_common_ancestors;
1594         struct tree *mrtree = mrtree;
1595         int clean;
1596
1597         if (show(o, 4)) {
1598                 output(o, 4, "Merging:");
1599                 output_commit_title(o, h1);
1600                 output_commit_title(o, h2);
1601         }
1602
1603         if (!ca) {
1604                 ca = get_merge_bases(h1, h2, 1);
1605                 ca = reverse_commit_list(ca);
1606         }
1607
1608         if (show(o, 5)) {
1609                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1610                 for (iter = ca; iter; iter = iter->next)
1611                         output_commit_title(o, iter->item);
1612         }
1613
1614         merged_common_ancestors = pop_commit(&ca);
1615         if (merged_common_ancestors == NULL) {
1616                 /* if there is no common ancestor, make an empty tree */
1617                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1618
1619                 tree->object.parsed = 1;
1620                 tree->object.type = OBJ_TREE;
1621                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1622                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1623         }
1624
1625         for (iter = ca; iter; iter = iter->next) {
1626                 const char *saved_b1, *saved_b2;
1627                 o->call_depth++;
1628                 /*
1629                  * When the merge fails, the result contains files
1630                  * with conflict markers. The cleanness flag is
1631                  * ignored, it was never actually used, as result of
1632                  * merge_trees has always overwritten it: the committed
1633                  * "conflicts" were already resolved.
1634                  */
1635                 discard_cache();
1636                 saved_b1 = o->branch1;
1637                 saved_b2 = o->branch2;
1638                 o->branch1 = "Temporary merge branch 1";
1639                 o->branch2 = "Temporary merge branch 2";
1640                 merge_recursive(o, merged_common_ancestors, iter->item,
1641                                 NULL, &merged_common_ancestors);
1642                 o->branch1 = saved_b1;
1643                 o->branch2 = saved_b2;
1644                 o->call_depth--;
1645
1646                 if (!merged_common_ancestors)
1647                         die("merge returned no commit");
1648         }
1649
1650         discard_cache();
1651         if (!o->call_depth)
1652                 read_cache();
1653
1654         o->ancestor = "merged common ancestors";
1655         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1656                             &mrtree);
1657
1658         if (o->call_depth) {
1659                 *result = make_virtual_commit(mrtree, "merged tree");
1660                 commit_list_insert(h1, &(*result)->parents);
1661                 commit_list_insert(h2, &(*result)->parents->next);
1662         }
1663         flush_output(o);
1664         if (show(o, 2))
1665                 diff_warn_rename_limit("merge.renamelimit",
1666                                        o->needed_rename_limit, 0);
1667         return clean;
1668 }
1669
1670 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1671 {
1672         struct object *object;
1673
1674         object = deref_tag(parse_object(sha1), name, strlen(name));
1675         if (!object)
1676                 return NULL;
1677         if (object->type == OBJ_TREE)
1678                 return make_virtual_commit((struct tree*)object, name);
1679         if (object->type != OBJ_COMMIT)
1680                 return NULL;
1681         if (parse_commit((struct commit *)object))
1682                 return NULL;
1683         return (struct commit *)object;
1684 }
1685
1686 int merge_recursive_generic(struct merge_options *o,
1687                             const unsigned char *head,
1688                             const unsigned char *merge,
1689                             int num_base_list,
1690                             const unsigned char **base_list,
1691                             struct commit **result)
1692 {
1693         int clean, index_fd;
1694         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1695         struct commit *head_commit = get_ref(head, o->branch1);
1696         struct commit *next_commit = get_ref(merge, o->branch2);
1697         struct commit_list *ca = NULL;
1698
1699         if (base_list) {
1700                 int i;
1701                 for (i = 0; i < num_base_list; ++i) {
1702                         struct commit *base;
1703                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1704                                 return error("Could not parse object '%s'",
1705                                         sha1_to_hex(base_list[i]));
1706                         commit_list_insert(base, &ca);
1707                 }
1708         }
1709
1710         index_fd = hold_locked_index(lock, 1);
1711         clean = merge_recursive(o, head_commit, next_commit, ca,
1712                         result);
1713         if (active_cache_changed &&
1714                         (write_cache(index_fd, active_cache, active_nr) ||
1715                          commit_locked_index(lock)))
1716                 return error("Unable to write index.");
1717
1718         return clean ? 0 : 1;
1719 }
1720
1721 static int merge_recursive_config(const char *var, const char *value, void *cb)
1722 {
1723         struct merge_options *o = cb;
1724         if (!strcmp(var, "merge.verbosity")) {
1725                 o->verbosity = git_config_int(var, value);
1726                 return 0;
1727         }
1728         if (!strcmp(var, "diff.renamelimit")) {
1729                 o->diff_rename_limit = git_config_int(var, value);
1730                 return 0;
1731         }
1732         if (!strcmp(var, "merge.renamelimit")) {
1733                 o->merge_rename_limit = git_config_int(var, value);
1734                 return 0;
1735         }
1736         return git_xmerge_config(var, value, cb);
1737 }
1738
1739 void init_merge_options(struct merge_options *o)
1740 {
1741         memset(o, 0, sizeof(struct merge_options));
1742         o->verbosity = 2;
1743         o->buffer_output = 1;
1744         o->diff_rename_limit = -1;
1745         o->merge_rename_limit = -1;
1746         o->renormalize = 0;
1747         git_config(merge_recursive_config, o);
1748         if (getenv("GIT_MERGE_VERBOSITY"))
1749                 o->verbosity =
1750                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1751         if (o->verbosity >= 5)
1752                 o->buffer_output = 0;
1753         strbuf_init(&o->obuf, 0);
1754         memset(&o->current_file_set, 0, sizeof(struct string_list));
1755         o->current_file_set.strdup_strings = 1;
1756         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1757         o->current_directory_set.strdup_strings = 1;
1758 }
1759
1760 int parse_merge_opt(struct merge_options *o, const char *s)
1761 {
1762         if (!s || !*s)
1763                 return -1;
1764         if (!strcmp(s, "ours"))
1765                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1766         else if (!strcmp(s, "theirs"))
1767                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1768         else if (!strcmp(s, "subtree"))
1769                 o->subtree_shift = "";
1770         else if (!prefixcmp(s, "subtree="))
1771                 o->subtree_shift = s + strlen("subtree=");
1772         else if (!strcmp(s, "patience"))
1773                 o->xdl_opts |= XDF_PATIENCE_DIFF;
1774         else if (!strcmp(s, "ignore-space-change"))
1775                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1776         else if (!strcmp(s, "ignore-all-space"))
1777                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
1778         else if (!strcmp(s, "ignore-space-at-eol"))
1779                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
1780         else if (!strcmp(s, "renormalize"))
1781                 o->renormalize = 1;
1782         else if (!strcmp(s, "no-renormalize"))
1783                 o->renormalize = 0;
1784         else if (!prefixcmp(s, "rename-threshold=")) {
1785                 const char *score = s + strlen("rename-threshold=");
1786                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
1787                         return -1;
1788         }
1789         else
1790                 return -1;
1791         return 0;
1792 }