git.oblomov.eu Git - git/blob - merge-recursive.c

   1 /*
   2  * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3  * Fredrik Kuivinen.
   4  * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5  */
   6 #include "advice.h"
   7 #include "cache.h"
   8 #include "cache-tree.h"
   9 #include "commit.h"
  10 #include "blob.h"
  11 #include "builtin.h"
  12 #include "tree-walk.h"
  13 #include "diff.h"
  14 #include "diffcore.h"
  15 #include "tag.h"
  16 #include "unpack-trees.h"
  17 #include "string-list.h"
  18 #include "xdiff-interface.h"
  19 #include "ll-merge.h"
  20 #include "attr.h"
  21 #include "merge-recursive.h"
  22 #include "dir.h"
  23 #include "submodule.h"
  24
  25 static const char rename_limit_advice[] =
  26 "inexact rename detection was skipped because there were too many\n"
  27 "  files. You may want to set your merge.renamelimit variable to at least\n"
  28 "  %d and retry this merge.";
  29
  30 static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  31                                       const char *subtree_shift)
  32 {
  33         unsigned char shifted[20];
  34
  35         if (!*subtree_shift) {
  36                 shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  37         } else {
  38                 shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  39                               subtree_shift);
  40         }
  41         if (!hashcmp(two->object.sha1, shifted))
  42                 return two;
  43         return lookup_tree(shifted);
  44 }
  45
  46 /*
  47  * A virtual commit has (const char *)commit->util set to the name.
  48  */
  49
  50 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  51 {
  52         struct commit *commit = xcalloc(1, sizeof(struct commit));
  53         commit->tree = tree;
  54         commit->util = (void*)comment;
  55         /* avoid warnings */
  56         commit->object.parsed = 1;
  57         return commit;
  58 }
  59
  60 /*
  61  * Since we use get_tree_entry(), which does not put the read object into
  62  * the object pool, we cannot rely on a == b.
  63  */
  64 static int sha_eq(const unsigned char *a, const unsigned char *b)
  65 {
  66         if (!a && !b)
  67                 return 2;
  68         return a && b && hashcmp(a, b) == 0;
  69 }
  70
  71 enum rename_type {
  72         RENAME_NORMAL = 0,
  73         RENAME_DELETE,
  74         RENAME_ONE_FILE_TO_TWO
  75 };
  76
  77 struct rename_df_conflict_info {
  78         enum rename_type rename_type;
  79         struct diff_filepair *pair1;
  80         struct diff_filepair *pair2;
  81         const char *branch1;
  82         const char *branch2;
  83         struct stage_data *dst_entry1;
  84         struct stage_data *dst_entry2;
  85 };
  86
  87 /*
  88  * Since we want to write the index eventually, we cannot reuse the index
  89  * for these (temporary) data.
  90  */
  91 struct stage_data
  92 {
  93         struct
  94         {
  95                 unsigned mode;
  96                 unsigned char sha[20];
  97         } stages[4];
  98         struct rename_df_conflict_info *rename_df_conflict_info;
  99         unsigned processed:1;
 100 };
 101
 102 static inline void setup_rename_df_conflict_info(enum rename_type rename_type,
 103                                                  struct diff_filepair *pair1,
 104                                                  struct diff_filepair *pair2,
 105                                                  const char *branch1,
 106                                                  const char *branch2,
 107                                                  struct stage_data *dst_entry1,
 108                                                  struct stage_data *dst_entry2)
 109 {
 110         struct rename_df_conflict_info *ci = xcalloc(1, sizeof(struct rename_df_conflict_info));
 111         ci->rename_type = rename_type;
 112         ci->pair1 = pair1;
 113         ci->branch1 = branch1;
 114         ci->branch2 = branch2;
 115
 116         ci->dst_entry1 = dst_entry1;
 117         dst_entry1->rename_df_conflict_info = ci;
 118         dst_entry1->processed = 0;
 119
 120         assert(!pair2 == !dst_entry2);
 121         if (dst_entry2) {
 122                 ci->dst_entry2 = dst_entry2;
 123                 ci->pair2 = pair2;
 124                 dst_entry2->rename_df_conflict_info = ci;
 125                 dst_entry2->processed = 0;
 126         }
 127 }
 128
 129 static int show(struct merge_options *o, int v)
 130 {
 131         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 132 }
 133
 134 static void flush_output(struct merge_options *o)
 135 {
 136         if (o->obuf.len) {
 137                 fputs(o->obuf.buf, stdout);
 138                 strbuf_reset(&o->obuf);
 139         }
 140 }
 141
 142 __attribute__((format (printf, 3, 4)))
 143 static void output(struct merge_options *o, int v, const char *fmt, ...)
 144 {
 145         int len;
 146         va_list ap;
 147
 148         if (!show(o, v))
 149                 return;
 150
 151         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 152         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 153         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 154
 155         va_start(ap, fmt);
 156         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 157         va_end(ap);
 158
 159         if (len < 0)
 160                 len = 0;
 161         if (len >= strbuf_avail(&o->obuf)) {
 162                 strbuf_grow(&o->obuf, len + 2);
 163                 va_start(ap, fmt);
 164                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 165                 va_end(ap);
 166                 if (len >= strbuf_avail(&o->obuf)) {
 167                         die("this should not happen, your snprintf is broken");
 168                 }
 169         }
 170         strbuf_setlen(&o->obuf, o->obuf.len + len);
 171         strbuf_add(&o->obuf, "\n", 1);
 172         if (!o->buffer_output)
 173                 flush_output(o);
 174 }
 175
 176 static void output_commit_title(struct merge_options *o, struct commit *commit)
 177 {
 178         int i;
 179         flush_output(o);
 180         for (i = o->call_depth; i--;)
 181                 fputs("  ", stdout);
 182         if (commit->util)
 183                 printf("virtual %s\n", (char *)commit->util);
 184         else {
 185                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 186                 if (parse_commit(commit) != 0)
 187                         printf("(bad commit)\n");
 188                 else {
 189                         const char *title;
 190                         int len = find_commit_subject(commit->buffer, &title);
 191                         if (len)
 192                                 printf("%.*s\n", len, title);
 193                 }
 194         }
 195 }
 196
 197 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 198                 const char *path, int stage, int refresh, int options)
 199 {
 200         struct cache_entry *ce;
 201         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 202         if (!ce)
 203                 return error("addinfo_cache failed for path '%s'", path);
 204         return add_cache_entry(ce, options);
 205 }
 206
 207 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 208 {
 209         parse_tree(tree);
 210         init_tree_desc(desc, tree->buffer, tree->size);
 211 }
 212
 213 static int git_merge_trees(int index_only,
 214                            struct tree *common,
 215                            struct tree *head,
 216                            struct tree *merge)
 217 {
 218         int rc;
 219         struct tree_desc t[3];
 220         struct unpack_trees_options opts;
 221
 222         memset(&opts, 0, sizeof(opts));
 223         if (index_only)
 224                 opts.index_only = 1;
 225         else
 226                 opts.update = 1;
 227         opts.merge = 1;
 228         opts.head_idx = 2;
 229         opts.fn = threeway_merge;
 230         opts.src_index = &the_index;
 231         opts.dst_index = &the_index;
 232         setup_unpack_trees_porcelain(&opts, "merge");
 233
 234         init_tree_desc_from_tree(t+0, common);
 235         init_tree_desc_from_tree(t+1, head);
 236         init_tree_desc_from_tree(t+2, merge);
 237
 238         rc = unpack_trees(3, t, &opts);
 239         cache_tree_free(&active_cache_tree);
 240         return rc;
 241 }
 242
 243 struct tree *write_tree_from_memory(struct merge_options *o)
 244 {
 245         struct tree *result = NULL;
 246
 247         if (unmerged_cache()) {
 248                 int i;
 249                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 250                 for (i = 0; i < active_nr; i++) {
 251                         struct cache_entry *ce = active_cache[i];
 252                         if (ce_stage(ce))
 253                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 254                                         (int)ce_namelen(ce), ce->name);
 255                 }
 256                 die("Bug in merge-recursive.c");
 257         }
 258
 259         if (!active_cache_tree)
 260                 active_cache_tree = cache_tree();
 261
 262         if (!cache_tree_fully_valid(active_cache_tree) &&
 263             cache_tree_update(active_cache_tree,
 264                               active_cache, active_nr, 0, 0) < 0)
 265                 die("error building trees");
 266
 267         result = lookup_tree(active_cache_tree->sha1);
 268
 269         return result;
 270 }
 271
 272 static int save_files_dirs(const unsigned char *sha1,
 273                 const char *base, int baselen, const char *path,
 274                 unsigned int mode, int stage, void *context)
 275 {
 276         int len = strlen(path);
 277         char *newpath = xmalloc(baselen + len + 1);
 278         struct merge_options *o = context;
 279
 280         memcpy(newpath, base, baselen);
 281         memcpy(newpath + baselen, path, len);
 282         newpath[baselen + len] = '\0';
 283
 284         if (S_ISDIR(mode))
 285                 string_list_insert(&o->current_directory_set, newpath);
 286         else
 287                 string_list_insert(&o->current_file_set, newpath);
 288         free(newpath);
 289
 290         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 291 }
 292
 293 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 294 {
 295         int n;
 296         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 297                 return 0;
 298         n = o->current_file_set.nr + o->current_directory_set.nr;
 299         return n;
 300 }
 301
 302 /*
 303  * Returns an index_entry instance which doesn't have to correspond to
 304  * a real cache entry in Git's index.
 305  */
 306 static struct stage_data *insert_stage_data(const char *path,
 307                 struct tree *o, struct tree *a, struct tree *b,
 308                 struct string_list *entries)
 309 {
 310         struct string_list_item *item;
 311         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 312         get_tree_entry(o->object.sha1, path,
 313                         e->stages[1].sha, &e->stages[1].mode);
 314         get_tree_entry(a->object.sha1, path,
 315                         e->stages[2].sha, &e->stages[2].mode);
 316         get_tree_entry(b->object.sha1, path,
 317                         e->stages[3].sha, &e->stages[3].mode);
 318         item = string_list_insert(entries, path);
 319         item->util = e;
 320         return e;
 321 }
 322
 323 /*
 324  * Create a dictionary mapping file names to stage_data objects. The
 325  * dictionary contains one entry for every path with a non-zero stage entry.
 326  */
 327 static struct string_list *get_unmerged(void)
 328 {
 329         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 330         int i;
 331
 332         unmerged->strdup_strings = 1;
 333
 334         for (i = 0; i < active_nr; i++) {
 335                 struct string_list_item *item;
 336                 struct stage_data *e;
 337                 struct cache_entry *ce = active_cache[i];
 338                 if (!ce_stage(ce))
 339                         continue;
 340
 341                 item = string_list_lookup(unmerged, ce->name);
 342                 if (!item) {
 343                         item = string_list_insert(unmerged, ce->name);
 344                         item->util = xcalloc(1, sizeof(struct stage_data));
 345                 }
 346                 e = item->util;
 347                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 348                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 349         }
 350
 351         return unmerged;
 352 }
 353
 354 static void make_room_for_directories_of_df_conflicts(struct merge_options *o,
 355                                                       struct string_list *entries)
 356 {
 357         /* If there are D/F conflicts, and the paths currently exist
 358          * in the working copy as a file, we want to remove them to
 359          * make room for the corresponding directory.  Such paths will
 360          * later be processed in process_df_entry() at the end.  If
 361          * the corresponding directory ends up being removed by the
 362          * merge, then the file will be reinstated at that time;
 363          * otherwise, if the file is not supposed to be removed by the
 364          * merge, the contents of the file will be placed in another
 365          * unique filename.
 366          *
 367          * NOTE: This function relies on the fact that entries for a
 368          * D/F conflict will appear adjacent in the index, with the
 369          * entries for the file appearing before entries for paths
 370          * below the corresponding directory.
 371          */
 372         const char *last_file = NULL;
 373         int last_len = 0;
 374         struct stage_data *last_e;
 375         int i;
 376
 377         for (i = 0; i < entries->nr; i++) {
 378                 const char *path = entries->items[i].string;
 379                 int len = strlen(path);
 380                 struct stage_data *e = entries->items[i].util;
 381
 382                 /*
 383                  * Check if last_file & path correspond to a D/F conflict;
 384                  * i.e. whether path is last_file+'/'+<something>.
 385                  * If so, remove last_file to make room for path and friends.
 386                  */
 387                 if (last_file &&
 388                     len > last_len &&
 389                     memcmp(path, last_file, last_len) == 0 &&
 390                     path[last_len] == '/') {
 391                         output(o, 3, "Removing %s to make room for subdirectory; may re-add later.", last_file);
 392                         unlink(last_file);
 393                 }
 394
 395                 /*
 396                  * Determine whether path could exist as a file in the
 397                  * working directory as a possible D/F conflict.  This
 398                  * will only occur when it exists in stage 2 as a
 399                  * file.
 400                  */
 401                 if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 402                         last_file = path;
 403                         last_len = len;
 404                         last_e = e;
 405                 } else {
 406                         last_file = NULL;
 407                 }
 408         }
 409 }
 410
 411 struct rename
 412 {
 413         struct diff_filepair *pair;
 414         struct stage_data *src_entry;
 415         struct stage_data *dst_entry;
 416         unsigned processed:1;
 417 };
 418
 419 /*
 420  * Get information of all renames which occurred between 'o_tree' and
 421  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 422  * 'b_tree') to be able to associate the correct cache entries with
 423  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 424  */
 425 static struct string_list *get_renames(struct merge_options *o,
 426                                        struct tree *tree,
 427                                        struct tree *o_tree,
 428                                        struct tree *a_tree,
 429                                        struct tree *b_tree,
 430                                        struct string_list *entries)
 431 {
 432         int i;
 433         struct string_list *renames;
 434         struct diff_options opts;
 435
 436         renames = xcalloc(1, sizeof(struct string_list));
 437         diff_setup(&opts);
 438         DIFF_OPT_SET(&opts, RECURSIVE);
 439         opts.detect_rename = DIFF_DETECT_RENAME;
 440         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 441                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 442                             1000;
 443         opts.rename_score = o->rename_score;
 444         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 445         if (diff_setup_done(&opts) < 0)
 446                 die("diff setup failed");
 447         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 448         diffcore_std(&opts);
 449         if (opts.needed_rename_limit > o->needed_rename_limit)
 450                 o->needed_rename_limit = opts.needed_rename_limit;
 451         for (i = 0; i < diff_queued_diff.nr; ++i) {
 452                 struct string_list_item *item;
 453                 struct rename *re;
 454                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 455                 if (pair->status != 'R') {
 456                         diff_free_filepair(pair);
 457                         continue;
 458                 }
 459                 re = xmalloc(sizeof(*re));
 460                 re->processed = 0;
 461                 re->pair = pair;
 462                 item = string_list_lookup(entries, re->pair->one->path);
 463                 if (!item)
 464                         re->src_entry = insert_stage_data(re->pair->one->path,
 465                                         o_tree, a_tree, b_tree, entries);
 466                 else
 467                         re->src_entry = item->util;
 468
 469                 item = string_list_lookup(entries, re->pair->two->path);
 470                 if (!item)
 471                         re->dst_entry = insert_stage_data(re->pair->two->path,
 472                                         o_tree, a_tree, b_tree, entries);
 473                 else
 474                         re->dst_entry = item->util;
 475                 item = string_list_insert(renames, pair->one->path);
 476                 item->util = re;
 477         }
 478         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 479         diff_queued_diff.nr = 0;
 480         diff_flush(&opts);
 481         return renames;
 482 }
 483
 484 static int update_stages_options(const char *path, struct diff_filespec *o,
 485                          struct diff_filespec *a, struct diff_filespec *b,
 486                          int clear, int options)
 487 {
 488         if (clear)
 489                 if (remove_file_from_cache(path))
 490                         return -1;
 491         if (o)
 492                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 493                         return -1;
 494         if (a)
 495                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 496                         return -1;
 497         if (b)
 498                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 499                         return -1;
 500         return 0;
 501 }
 502
 503 static int update_stages(const char *path, struct diff_filespec *o,
 504                          struct diff_filespec *a, struct diff_filespec *b,
 505                          int clear)
 506 {
 507         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 508         return update_stages_options(path, o, a, b, clear, options);
 509 }
 510
 511 static int update_stages_and_entry(const char *path,
 512                                    struct stage_data *entry,
 513                                    struct diff_filespec *o,
 514                                    struct diff_filespec *a,
 515                                    struct diff_filespec *b,
 516                                    int clear)
 517 {
 518         int options;
 519
 520         entry->processed = 0;
 521         entry->stages[1].mode = o->mode;
 522         entry->stages[2].mode = a->mode;
 523         entry->stages[3].mode = b->mode;
 524         hashcpy(entry->stages[1].sha, o->sha1);
 525         hashcpy(entry->stages[2].sha, a->sha1);
 526         hashcpy(entry->stages[3].sha, b->sha1);
 527         options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 528         return update_stages_options(path, o, a, b, clear, options);
 529 }
 530
 531 static int remove_file(struct merge_options *o, int clean,
 532                        const char *path, int no_wd)
 533 {
 534         int update_cache = o->call_depth || clean;
 535         int update_working_directory = !o->call_depth && !no_wd;
 536
 537         if (update_cache) {
 538                 if (remove_file_from_cache(path))
 539                         return -1;
 540         }
 541         if (update_working_directory) {
 542                 if (remove_path(path))
 543                         return -1;
 544         }
 545         return 0;
 546 }
 547
 548 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 549 {
 550         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 551         int suffix = 0;
 552         struct stat st;
 553         char *p = newpath + strlen(path);
 554         strcpy(newpath, path);
 555         *(p++) = '~';
 556         strcpy(p, branch);
 557         for (; *p; ++p)
 558                 if ('/' == *p)
 559                         *p = '_';
 560         while (string_list_has_string(&o->current_file_set, newpath) ||
 561                string_list_has_string(&o->current_directory_set, newpath) ||
 562                lstat(newpath, &st) == 0)
 563                 sprintf(p, "_%d", suffix++);
 564
 565         string_list_insert(&o->current_file_set, newpath);
 566         return newpath;
 567 }
 568
 569 static void flush_buffer(int fd, const char *buf, unsigned long size)
 570 {
 571         while (size > 0) {
 572                 long ret = write_in_full(fd, buf, size);
 573                 if (ret < 0) {
 574                         /* Ignore epipe */
 575                         if (errno == EPIPE)
 576                                 break;
 577                         die_errno("merge-recursive");
 578                 } else if (!ret) {
 579                         die("merge-recursive: disk full?");
 580                 }
 581                 size -= ret;
 582                 buf += ret;
 583         }
 584 }
 585
 586 static int would_lose_untracked(const char *path)
 587 {
 588         int pos = cache_name_pos(path, strlen(path));
 589
 590         if (pos < 0)
 591                 pos = -1 - pos;
 592         while (pos < active_nr &&
 593                !strcmp(path, active_cache[pos]->name)) {
 594                 /*
 595                  * If stage #0, it is definitely tracked.
 596                  * If it has stage #2 then it was tracked
 597                  * before this merge started.  All other
 598                  * cases the path was not tracked.
 599                  */
 600                 switch (ce_stage(active_cache[pos])) {
 601                 case 0:
 602                 case 2:
 603                         return 0;
 604                 }
 605                 pos++;
 606         }
 607         return file_exists(path);
 608 }
 609
 610 static int make_room_for_path(const char *path)
 611 {
 612         int status;
 613         const char *msg = "failed to create path '%s'%s";
 614
 615         status = safe_create_leading_directories_const(path);
 616         if (status) {
 617                 if (status == -3) {
 618                         /* something else exists */
 619                         error(msg, path, ": perhaps a D/F conflict?");
 620                         return -1;
 621                 }
 622                 die(msg, path, "");
 623         }
 624
 625         /*
 626          * Do not unlink a file in the work tree if we are not
 627          * tracking it.
 628          */
 629         if (would_lose_untracked(path))
 630                 return error("refusing to lose untracked file at '%s'",
 631                              path);
 632
 633         /* Successful unlink is good.. */
 634         if (!unlink(path))
 635                 return 0;
 636         /* .. and so is no existing file */
 637         if (errno == ENOENT)
 638                 return 0;
 639         /* .. but not some other error (who really cares what?) */
 640         return error(msg, path, ": perhaps a D/F conflict?");
 641 }
 642
 643 static void update_file_flags(struct merge_options *o,
 644                               const unsigned char *sha,
 645                               unsigned mode,
 646                               const char *path,
 647                               int update_cache,
 648                               int update_wd)
 649 {
 650         if (o->call_depth)
 651                 update_wd = 0;
 652
 653         if (update_wd) {
 654                 enum object_type type;
 655                 void *buf;
 656                 unsigned long size;
 657
 658                 if (S_ISGITLINK(mode)) {
 659                         /*
 660                          * We may later decide to recursively descend into
 661                          * the submodule directory and update its index
 662                          * and/or work tree, but we do not do that now.
 663                          */
 664                         update_wd = 0;
 665                         goto update_index;
 666                 }
 667
 668                 buf = read_sha1_file(sha, &type, &size);
 669                 if (!buf)
 670                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 671                 if (type != OBJ_BLOB)
 672                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 673                 if (S_ISREG(mode)) {
 674                         struct strbuf strbuf = STRBUF_INIT;
 675                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 676                                 free(buf);
 677                                 size = strbuf.len;
 678                                 buf = strbuf_detach(&strbuf, NULL);
 679                         }
 680                 }
 681
 682                 if (make_room_for_path(path) < 0) {
 683                         update_wd = 0;
 684                         free(buf);
 685                         goto update_index;
 686                 }
 687                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 688                         int fd;
 689                         if (mode & 0100)
 690                                 mode = 0777;
 691                         else
 692                                 mode = 0666;
 693                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 694                         if (fd < 0)
 695                                 die_errno("failed to open '%s'", path);
 696                         flush_buffer(fd, buf, size);
 697                         close(fd);
 698                 } else if (S_ISLNK(mode)) {
 699                         char *lnk = xmemdupz(buf, size);
 700                         safe_create_leading_directories_const(path);
 701                         unlink(path);
 702                         if (symlink(lnk, path))
 703                                 die_errno("failed to symlink '%s'", path);
 704                         free(lnk);
 705                 } else
 706                         die("do not know what to do with %06o %s '%s'",
 707                             mode, sha1_to_hex(sha), path);
 708                 free(buf);
 709         }
 710  update_index:
 711         if (update_cache)
 712                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 713 }
 714
 715 static void update_file(struct merge_options *o,
 716                         int clean,
 717                         const unsigned char *sha,
 718                         unsigned mode,
 719                         const char *path)
 720 {
 721         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 722 }
 723
 724 /* Low level file merging, update and removal */
 725
 726 struct merge_file_info
 727 {
 728         unsigned char sha[20];
 729         unsigned mode;
 730         unsigned clean:1,
 731                  merge:1;
 732 };
 733
 734 static int merge_3way(struct merge_options *o,
 735                       mmbuffer_t *result_buf,
 736                       struct diff_filespec *one,
 737                       struct diff_filespec *a,
 738                       struct diff_filespec *b,
 739                       const char *branch1,
 740                       const char *branch2)
 741 {
 742         mmfile_t orig, src1, src2;
 743         struct ll_merge_options ll_opts = {0};
 744         char *base_name, *name1, *name2;
 745         int merge_status;
 746
 747         ll_opts.renormalize = o->renormalize;
 748         ll_opts.xdl_opts = o->xdl_opts;
 749
 750         if (o->call_depth) {
 751                 ll_opts.virtual_ancestor = 1;
 752                 ll_opts.variant = 0;
 753         } else {
 754                 switch (o->recursive_variant) {
 755                 case MERGE_RECURSIVE_OURS:
 756                         ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 757                         break;
 758                 case MERGE_RECURSIVE_THEIRS:
 759                         ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 760                         break;
 761                 default:
 762                         ll_opts.variant = 0;
 763                         break;
 764                 }
 765         }
 766
 767         if (strcmp(a->path, b->path) ||
 768             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 769                 base_name = o->ancestor == NULL ? NULL :
 770                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 771                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 772                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 773         } else {
 774                 base_name = o->ancestor == NULL ? NULL :
 775                         xstrdup(mkpath("%s", o->ancestor));
 776                 name1 = xstrdup(mkpath("%s", branch1));
 777                 name2 = xstrdup(mkpath("%s", branch2));
 778         }
 779
 780         read_mmblob(&orig, one->sha1);
 781         read_mmblob(&src1, a->sha1);
 782         read_mmblob(&src2, b->sha1);
 783
 784         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 785                                 &src1, name1, &src2, name2, &ll_opts);
 786
 787         free(name1);
 788         free(name2);
 789         free(orig.ptr);
 790         free(src1.ptr);
 791         free(src2.ptr);
 792         return merge_status;
 793 }
 794
 795 static struct merge_file_info merge_file(struct merge_options *o,
 796                                          struct diff_filespec *one,
 797                                          struct diff_filespec *a,
 798                                          struct diff_filespec *b,
 799                                          const char *branch1,
 800                                          const char *branch2)
 801 {
 802         struct merge_file_info result;
 803         result.merge = 0;
 804         result.clean = 1;
 805
 806         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 807                 result.clean = 0;
 808                 if (S_ISREG(a->mode)) {
 809                         result.mode = a->mode;
 810                         hashcpy(result.sha, a->sha1);
 811                 } else {
 812                         result.mode = b->mode;
 813                         hashcpy(result.sha, b->sha1);
 814                 }
 815         } else {
 816                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 817                         result.merge = 1;
 818
 819                 /*
 820                  * Merge modes
 821                  */
 822                 if (a->mode == b->mode || a->mode == one->mode)
 823                         result.mode = b->mode;
 824                 else {
 825                         result.mode = a->mode;
 826                         if (b->mode != one->mode) {
 827                                 result.clean = 0;
 828                                 result.merge = 1;
 829                         }
 830                 }
 831
 832                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 833                         hashcpy(result.sha, b->sha1);
 834                 else if (sha_eq(b->sha1, one->sha1))
 835                         hashcpy(result.sha, a->sha1);
 836                 else if (S_ISREG(a->mode)) {
 837                         mmbuffer_t result_buf;
 838                         int merge_status;
 839
 840                         merge_status = merge_3way(o, &result_buf, one, a, b,
 841                                                   branch1, branch2);
 842
 843                         if ((merge_status < 0) || !result_buf.ptr)
 844                                 die("Failed to execute internal merge");
 845
 846                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 847                                             blob_type, result.sha))
 848                                 die("Unable to add %s to database",
 849                                     a->path);
 850
 851                         free(result_buf.ptr);
 852                         result.clean = (merge_status == 0);
 853                 } else if (S_ISGITLINK(a->mode)) {
 854                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 855                                                        a->sha1, b->sha1);
 856                 } else if (S_ISLNK(a->mode)) {
 857                         hashcpy(result.sha, a->sha1);
 858
 859                         if (!sha_eq(a->sha1, b->sha1))
 860                                 result.clean = 0;
 861                 } else {
 862                         die("unsupported object type in the tree");
 863                 }
 864         }
 865
 866         return result;
 867 }
 868
 869 static void conflict_rename_delete(struct merge_options *o,
 870                                    struct diff_filepair *pair,
 871                                    const char *rename_branch,
 872                                    const char *other_branch)
 873 {
 874         char *dest_name = pair->two->path;
 875         int df_conflict = 0;
 876         struct stat st;
 877
 878         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 879                "and deleted in %s",
 880                pair->one->path, pair->two->path, rename_branch,
 881                other_branch);
 882         if (!o->call_depth)
 883                 update_stages(dest_name, NULL,
 884                               rename_branch == o->branch1 ? pair->two : NULL,
 885                               rename_branch == o->branch1 ? NULL : pair->two,
 886                               1);
 887         if (lstat(dest_name, &st) == 0 && S_ISDIR(st.st_mode)) {
 888                 dest_name = unique_path(o, dest_name, rename_branch);
 889                 df_conflict = 1;
 890         }
 891         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 892         if (df_conflict)
 893                 free(dest_name);
 894 }
 895
 896 static void conflict_rename_rename_1to2(struct merge_options *o,
 897                                         struct diff_filepair *pair1,
 898                                         const char *branch1,
 899                                         struct diff_filepair *pair2,
 900                                         const char *branch2)
 901 {
 902         /* One file was renamed in both branches, but to different names. */
 903         char *del[2];
 904         int delp = 0;
 905         const char *ren1_dst = pair1->two->path;
 906         const char *ren2_dst = pair2->two->path;
 907         const char *dst_name1 = ren1_dst;
 908         const char *dst_name2 = ren2_dst;
 909         struct stat st;
 910         if (lstat(ren1_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 911                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 912                 output(o, 1, "%s is a directory in %s adding as %s instead",
 913                        ren1_dst, branch2, dst_name1);
 914         }
 915         if (lstat(ren2_dst, &st) == 0 && S_ISDIR(st.st_mode)) {
 916                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 917                 output(o, 1, "%s is a directory in %s adding as %s instead",
 918                        ren2_dst, branch1, dst_name2);
 919         }
 920         if (o->call_depth) {
 921                 remove_file_from_cache(dst_name1);
 922                 remove_file_from_cache(dst_name2);
 923                 /*
 924                  * Uncomment to leave the conflicting names in the resulting tree
 925                  *
 926                  * update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 927                  * update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 928                  */
 929         } else {
 930                 update_stages(ren1_dst, NULL, pair1->two, NULL, 1);
 931                 update_stages(ren2_dst, NULL, NULL, pair2->two, 1);
 932
 933                 update_file(o, 0, pair1->two->sha1, pair1->two->mode, dst_name1);
 934                 update_file(o, 0, pair2->two->sha1, pair2->two->mode, dst_name2);
 935         }
 936         while (delp--)
 937                 free(del[delp]);
 938 }
 939
 940 static void conflict_rename_rename_2to1(struct merge_options *o,
 941                                         struct rename *ren1,
 942                                         const char *branch1,
 943                                         struct rename *ren2,
 944                                         const char *branch2)
 945 {
 946         /* Two files were renamed to the same thing. */
 947         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 948         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 949         output(o, 1, "Renaming %s to %s and %s to %s instead",
 950                ren1->pair->one->path, new_path1,
 951                ren2->pair->one->path, new_path2);
 952         remove_file(o, 0, ren1->pair->two->path, 0);
 953         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 954         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 955         free(new_path2);
 956         free(new_path1);
 957 }
 958
 959 static int process_renames(struct merge_options *o,
 960                            struct string_list *a_renames,
 961                            struct string_list *b_renames)
 962 {
 963         int clean_merge = 1, i, j;
 964         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 965         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 966         const struct rename *sre;
 967
 968         for (i = 0; i < a_renames->nr; i++) {
 969                 sre = a_renames->items[i].util;
 970                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 971                         = sre->dst_entry;
 972         }
 973         for (i = 0; i < b_renames->nr; i++) {
 974                 sre = b_renames->items[i].util;
 975                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 976                         = sre->dst_entry;
 977         }
 978
 979         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 980                 char *src;
 981                 struct string_list *renames1, *renames2Dst;
 982                 struct rename *ren1 = NULL, *ren2 = NULL;
 983                 const char *branch1, *branch2;
 984                 const char *ren1_src, *ren1_dst;
 985
 986                 if (i >= a_renames->nr) {
 987                         ren2 = b_renames->items[j++].util;
 988                 } else if (j >= b_renames->nr) {
 989                         ren1 = a_renames->items[i++].util;
 990                 } else {
 991                         int compare = strcmp(a_renames->items[i].string,
 992                                              b_renames->items[j].string);
 993                         if (compare <= 0)
 994                                 ren1 = a_renames->items[i++].util;
 995                         if (compare >= 0)
 996                                 ren2 = b_renames->items[j++].util;
 997                 }
 998
 999                 /* TODO: refactor, so that 1/2 are not needed */
1000                 if (ren1) {
1001                         renames1 = a_renames;
1002                         renames2Dst = &b_by_dst;
1003                         branch1 = o->branch1;
1004                         branch2 = o->branch2;
1005                 } else {
1006                         struct rename *tmp;
1007                         renames1 = b_renames;
1008                         renames2Dst = &a_by_dst;
1009                         branch1 = o->branch2;
1010                         branch2 = o->branch1;
1011                         tmp = ren2;
1012                         ren2 = ren1;
1013                         ren1 = tmp;
1014                 }
1015                 src = ren1->pair->one->path;
1016
1017                 ren1->dst_entry->processed = 1;
1018                 ren1->src_entry->processed = 1;
1019
1020                 if (ren1->processed)
1021                         continue;
1022                 ren1->processed = 1;
1023
1024                 ren1_src = ren1->pair->one->path;
1025                 ren1_dst = ren1->pair->two->path;
1026
1027                 if (ren2) {
1028                         const char *ren2_src = ren2->pair->one->path;
1029                         const char *ren2_dst = ren2->pair->two->path;
1030                         /* Renamed in 1 and renamed in 2 */
1031                         if (strcmp(ren1_src, ren2_src) != 0)
1032                                 die("ren1.src != ren2.src");
1033                         ren2->dst_entry->processed = 1;
1034                         ren2->processed = 1;
1035                         if (strcmp(ren1_dst, ren2_dst) != 0) {
1036                                 setup_rename_df_conflict_info(RENAME_ONE_FILE_TO_TWO,
1037                                                               ren1->pair,
1038                                                               ren2->pair,
1039                                                               branch1,
1040                                                               branch2,
1041                                                               ren1->dst_entry,
1042                                                               ren2->dst_entry);
1043                         } else {
1044                                 remove_file(o, 1, ren1_src, 1);
1045                                 update_stages_and_entry(ren1_dst,
1046                                                         ren1->dst_entry,
1047                                                         ren1->pair->one,
1048                                                         ren1->pair->two,
1049                                                         ren2->pair->two,
1050                                                         1 /* clear */);
1051                         }
1052                 } else {
1053                         /* Renamed in 1, maybe changed in 2 */
1054                         struct string_list_item *item;
1055                         /* we only use sha1 and mode of these */
1056                         struct diff_filespec src_other, dst_other;
1057                         int try_merge;
1058
1059                         /*
1060                          * unpack_trees loads entries from common-commit
1061                          * into stage 1, from head-commit into stage 2, and
1062                          * from merge-commit into stage 3.  We keep track
1063                          * of which side corresponds to the rename.
1064                          */
1065                         int renamed_stage = a_renames == renames1 ? 2 : 3;
1066                         int other_stage =   a_renames == renames1 ? 3 : 2;
1067
1068                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
1069
1070                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
1071                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
1072                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
1073                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1074                         try_merge = 0;
1075
1076                         if (sha_eq(src_other.sha1, null_sha1)) {
1077                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1078                                         ren1->dst_entry->processed = 0;
1079                                         setup_rename_df_conflict_info(RENAME_DELETE,
1080                                                                       ren1->pair,
1081                                                                       NULL,
1082                                                                       branch1,
1083                                                                       branch2,
1084                                                                       ren1->dst_entry,
1085                                                                       NULL);
1086                                 } else {
1087                                         clean_merge = 0;
1088                                         conflict_rename_delete(o, ren1->pair, branch1, branch2);
1089                                 }
1090                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
1091                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
1092                                 /* Added file on the other side
1093                                    identical to the file being
1094                                    renamed: clean merge */
1095                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
1096                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
1097                                 const char *new_path;
1098                                 clean_merge = 0;
1099                                 try_merge = 1;
1100                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
1101                                        "%s added in %s",
1102                                        ren1_src, ren1_dst, branch1,
1103                                        ren1_dst, branch2);
1104                                 if (o->call_depth) {
1105                                         struct merge_file_info mfi;
1106                                         struct diff_filespec one, a, b;
1107
1108                                         one.path = a.path = b.path =
1109                                                 (char *)ren1_dst;
1110                                         hashcpy(one.sha1, null_sha1);
1111                                         one.mode = 0;
1112                                         hashcpy(a.sha1, ren1->pair->two->sha1);
1113                                         a.mode = ren1->pair->two->mode;
1114                                         hashcpy(b.sha1, dst_other.sha1);
1115                                         b.mode = dst_other.mode;
1116                                         mfi = merge_file(o, &one, &a, &b,
1117                                                          branch1,
1118                                                          branch2);
1119                                         output(o, 1, "Adding merged %s", ren1_dst);
1120                                         update_file(o, 0,
1121                                                     mfi.sha,
1122                                                     mfi.mode,
1123                                                     ren1_dst);
1124                                         try_merge = 0;
1125                                 } else {
1126                                         new_path = unique_path(o, ren1_dst, branch2);
1127                                         output(o, 1, "Adding as %s instead", new_path);
1128                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1129                                 }
1130                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
1131                                 ren2 = item->util;
1132                                 clean_merge = 0;
1133                                 ren2->processed = 1;
1134                                 output(o, 1, "CONFLICT (rename/rename): "
1135                                        "Rename %s->%s in %s. "
1136                                        "Rename %s->%s in %s",
1137                                        ren1_src, ren1_dst, branch1,
1138                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1139                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1140                         } else
1141                                 try_merge = 1;
1142
1143                         if (try_merge) {
1144                                 struct diff_filespec *one, *a, *b;
1145                                 src_other.path = (char *)ren1_src;
1146
1147                                 one = ren1->pair->one;
1148                                 if (a_renames == renames1) {
1149                                         a = ren1->pair->two;
1150                                         b = &src_other;
1151                                 } else {
1152                                         b = ren1->pair->two;
1153                                         a = &src_other;
1154                                 }
1155                                 update_stages_and_entry(ren1_dst, ren1->dst_entry, one, a, b, 1);
1156                                 if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
1157                                         setup_rename_df_conflict_info(RENAME_NORMAL,
1158                                                                       ren1->pair,
1159                                                                       NULL,
1160                                                                       branch1,
1161                                                                       NULL,
1162                                                                       ren1->dst_entry,
1163                                                                       NULL);
1164                                 }
1165                         }
1166                 }
1167         }
1168         string_list_clear(&a_by_dst, 0);
1169         string_list_clear(&b_by_dst, 0);
1170
1171         return clean_merge;
1172 }
1173
1174 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1175 {
1176         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1177 }
1178
1179 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1180 {
1181         void *buf;
1182         enum object_type type;
1183         unsigned long size;
1184         buf = read_sha1_file(sha1, &type, &size);
1185         if (!buf)
1186                 return error("cannot read object %s", sha1_to_hex(sha1));
1187         if (type != OBJ_BLOB) {
1188                 free(buf);
1189                 return error("object %s is not a blob", sha1_to_hex(sha1));
1190         }
1191         strbuf_attach(dst, buf, size, size + 1);
1192         return 0;
1193 }
1194
1195 static int blob_unchanged(const unsigned char *o_sha,
1196                           const unsigned char *a_sha,
1197                           int renormalize, const char *path)
1198 {
1199         struct strbuf o = STRBUF_INIT;
1200         struct strbuf a = STRBUF_INIT;
1201         int ret = 0; /* assume changed for safety */
1202
1203         if (sha_eq(o_sha, a_sha))
1204                 return 1;
1205         if (!renormalize)
1206                 return 0;
1207
1208         assert(o_sha && a_sha);
1209         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1210                 goto error_return;
1211         /*
1212          * Note: binary | is used so that both renormalizations are
1213          * performed.  Comparison can be skipped if both files are
1214          * unchanged since their sha1s have already been compared.
1215          */
1216         if (renormalize_buffer(path, o.buf, o.len, &o) |
1217             renormalize_buffer(path, a.buf, o.len, &a))
1218                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1219
1220 error_return:
1221         strbuf_release(&o);
1222         strbuf_release(&a);
1223         return ret;
1224 }
1225
1226 static void handle_delete_modify(struct merge_options *o,
1227                                  const char *path,
1228                                  const char *new_path,
1229                                  unsigned char *a_sha, int a_mode,
1230                                  unsigned char *b_sha, int b_mode)
1231 {
1232         if (!a_sha) {
1233                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1234                        "and modified in %s. Version %s of %s left in tree%s%s.",
1235                        path, o->branch1,
1236                        o->branch2, o->branch2, path,
1237                        path == new_path ? "" : " at ",
1238                        path == new_path ? "" : new_path);
1239                 update_file(o, 0, b_sha, b_mode, new_path);
1240         } else {
1241                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1242                        "and modified in %s. Version %s of %s left in tree%s%s.",
1243                        path, o->branch2,
1244                        o->branch1, o->branch1, path,
1245                        path == new_path ? "" : " at ",
1246                        path == new_path ? "" : new_path);
1247                 update_file(o, 0, a_sha, a_mode, new_path);
1248         }
1249 }
1250
1251 static int merge_content(struct merge_options *o,
1252                          const char *path,
1253                          unsigned char *o_sha, int o_mode,
1254                          unsigned char *a_sha, int a_mode,
1255                          unsigned char *b_sha, int b_mode,
1256                          const char *df_rename_conflict_branch)
1257 {
1258         const char *reason = "content";
1259         struct merge_file_info mfi;
1260         struct diff_filespec one, a, b;
1261         struct stat st;
1262         unsigned df_conflict_remains = 0;
1263
1264         if (!o_sha) {
1265                 reason = "add/add";
1266                 o_sha = (unsigned char *)null_sha1;
1267         }
1268         one.path = a.path = b.path = (char *)path;
1269         hashcpy(one.sha1, o_sha);
1270         one.mode = o_mode;
1271         hashcpy(a.sha1, a_sha);
1272         a.mode = a_mode;
1273         hashcpy(b.sha1, b_sha);
1274         b.mode = b_mode;
1275
1276         mfi = merge_file(o, &one, &a, &b, o->branch1, o->branch2);
1277         if (df_rename_conflict_branch &&
1278             lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1279                 df_conflict_remains = 1;
1280         }
1281
1282         if (mfi.clean && !df_conflict_remains &&
1283             sha_eq(mfi.sha, a_sha) && mfi.mode == a.mode)
1284                 output(o, 3, "Skipped %s (merged same as existing)", path);
1285         else
1286                 output(o, 2, "Auto-merging %s", path);
1287
1288         if (!mfi.clean) {
1289                 if (S_ISGITLINK(mfi.mode))
1290                         reason = "submodule";
1291                 output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1292                                 reason, path);
1293         }
1294
1295         if (df_conflict_remains) {
1296                 const char *new_path;
1297                 update_file_flags(o, mfi.sha, mfi.mode, path,
1298                                   o->call_depth || mfi.clean, 0);
1299                 new_path = unique_path(o, path, df_rename_conflict_branch);
1300                 mfi.clean = 0;
1301                 output(o, 1, "Adding as %s instead", new_path);
1302                 update_file_flags(o, mfi.sha, mfi.mode, new_path, 0, 1);
1303         } else {
1304                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1305         }
1306         return mfi.clean;
1307
1308 }
1309
1310 /* Per entry merge function */
1311 static int process_entry(struct merge_options *o,
1312                          const char *path, struct stage_data *entry)
1313 {
1314         /*
1315         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1316         print_index_entry("\tpath: ", entry);
1317         */
1318         int clean_merge = 1;
1319         int normalize = o->renormalize;
1320         unsigned o_mode = entry->stages[1].mode;
1321         unsigned a_mode = entry->stages[2].mode;
1322         unsigned b_mode = entry->stages[3].mode;
1323         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1324         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1325         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1326
1327         if (entry->rename_df_conflict_info)
1328                 return 1; /* Such cases are handled elsewhere. */
1329
1330         entry->processed = 1;
1331         if (o_sha && (!a_sha || !b_sha)) {
1332                 /* Case A: Deleted in one */
1333                 if ((!a_sha && !b_sha) ||
1334                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1335                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1336                         /* Deleted in both or deleted in one and
1337                          * unchanged in the other */
1338                         if (a_sha)
1339                                 output(o, 2, "Removing %s", path);
1340                         /* do not touch working file if it did not exist */
1341                         remove_file(o, 1, path, !a_sha);
1342                 } else if (string_list_has_string(&o->current_directory_set,
1343                                                   path)) {
1344                         entry->processed = 0;
1345                         return 1; /* Assume clean until processed */
1346                 } else {
1347                         /* Deleted in one and changed in the other */
1348                         clean_merge = 0;
1349                         handle_delete_modify(o, path, path,
1350                                              a_sha, a_mode, b_sha, b_mode);
1351                 }
1352
1353         } else if ((!o_sha && a_sha && !b_sha) ||
1354                    (!o_sha && !a_sha && b_sha)) {
1355                 /* Case B: Added in one. */
1356                 unsigned mode;
1357                 const unsigned char *sha;
1358
1359                 if (a_sha) {
1360                         mode = a_mode;
1361                         sha = a_sha;
1362                 } else {
1363                         mode = b_mode;
1364                         sha = b_sha;
1365                 }
1366                 if (string_list_has_string(&o->current_directory_set, path)) {
1367                         /* Handle D->F conflicts after all subfiles */
1368                         entry->processed = 0;
1369                         return 1; /* Assume clean until processed */
1370                 } else {
1371                         output(o, 2, "Adding %s", path);
1372                         update_file(o, 1, sha, mode, path);
1373                 }
1374         } else if (a_sha && b_sha) {
1375                 /* Case C: Added in both (check for same permissions) and */
1376                 /* case D: Modified in both, but differently. */
1377                 clean_merge = merge_content(o, path,
1378                                             o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1379                                             NULL);
1380         } else if (!o_sha && !a_sha && !b_sha) {
1381                 /*
1382                  * this entry was deleted altogether. a_mode == 0 means
1383                  * we had that path and want to actively remove it.
1384                  */
1385                 remove_file(o, 1, path, !a_mode);
1386         } else
1387                 die("Fatal merge failure, shouldn't happen.");
1388
1389         return clean_merge;
1390 }
1391
1392 /*
1393  * Per entry merge function for D/F (and/or rename) conflicts.  In the
1394  * cases we can cleanly resolve D/F conflicts, process_entry() can
1395  * clean out all the files below the directory for us.  All D/F
1396  * conflict cases must be handled here at the end to make sure any
1397  * directories that can be cleaned out, are.
1398  *
1399  * Some rename conflicts may also be handled here that don't necessarily
1400  * involve D/F conflicts, since the code to handle them is generic enough
1401  * to handle those rename conflicts with or without D/F conflicts also
1402  * being involved.
1403  */
1404 static int process_df_entry(struct merge_options *o,
1405                             const char *path, struct stage_data *entry)
1406 {
1407         int clean_merge = 1;
1408         unsigned o_mode = entry->stages[1].mode;
1409         unsigned a_mode = entry->stages[2].mode;
1410         unsigned b_mode = entry->stages[3].mode;
1411         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1412         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1413         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1414         struct stat st;
1415
1416         entry->processed = 1;
1417         if (entry->rename_df_conflict_info) {
1418                 struct rename_df_conflict_info *conflict_info = entry->rename_df_conflict_info;
1419                 char *src;
1420                 switch (conflict_info->rename_type) {
1421                 case RENAME_NORMAL:
1422                         clean_merge = merge_content(o, path,
1423                                                     o_sha, o_mode, a_sha, a_mode, b_sha, b_mode,
1424                                                     conflict_info->branch1);
1425                         break;
1426                 case RENAME_DELETE:
1427                         clean_merge = 0;
1428                         conflict_rename_delete(o, conflict_info->pair1,
1429                                                conflict_info->branch1,
1430                                                conflict_info->branch2);
1431                         break;
1432                 case RENAME_ONE_FILE_TO_TWO:
1433                         src = conflict_info->pair1->one->path;
1434                         clean_merge = 0;
1435                         output(o, 1, "CONFLICT (rename/rename): "
1436                                "Rename \"%s\"->\"%s\" in branch \"%s\" "
1437                                "rename \"%s\"->\"%s\" in \"%s\"%s",
1438                                src, conflict_info->pair1->two->path, conflict_info->branch1,
1439                                src, conflict_info->pair2->two->path, conflict_info->branch2,
1440                                o->call_depth ? " (left unresolved)" : "");
1441                         if (o->call_depth) {
1442                                 remove_file_from_cache(src);
1443                                 update_file(o, 0, conflict_info->pair1->one->sha1,
1444                                             conflict_info->pair1->one->mode, src);
1445                         }
1446                         conflict_rename_rename_1to2(o, conflict_info->pair1,
1447                                                     conflict_info->branch1,
1448                                                     conflict_info->pair2,
1449                                                     conflict_info->branch2);
1450                         conflict_info->dst_entry2->processed = 1;
1451                         break;
1452                 default:
1453                         entry->processed = 0;
1454                         break;
1455                 }
1456         } else if (o_sha && (!a_sha || !b_sha)) {
1457                 /* Modify/delete; deleted side may have put a directory in the way */
1458                 const char *new_path = path;
1459                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode))
1460                         new_path = unique_path(o, path, a_sha ? o->branch1 : o->branch2);
1461                 clean_merge = 0;
1462                 handle_delete_modify(o, path, new_path,
1463                                      a_sha, a_mode, b_sha, b_mode);
1464         } else if (!o_sha && !!a_sha != !!b_sha) {
1465                 /* directory -> (directory, file) */
1466                 const char *add_branch;
1467                 const char *other_branch;
1468                 unsigned mode;
1469                 const unsigned char *sha;
1470                 const char *conf;
1471
1472                 if (a_sha) {
1473                         add_branch = o->branch1;
1474                         other_branch = o->branch2;
1475                         mode = a_mode;
1476                         sha = a_sha;
1477                         conf = "file/directory";
1478                 } else {
1479                         add_branch = o->branch2;
1480                         other_branch = o->branch1;
1481                         mode = b_mode;
1482                         sha = b_sha;
1483                         conf = "directory/file";
1484                 }
1485                 if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1486                         const char *new_path = unique_path(o, path, add_branch);
1487                         clean_merge = 0;
1488                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1489                                "Adding %s as %s",
1490                                conf, path, other_branch, path, new_path);
1491                         update_file(o, 0, sha, mode, new_path);
1492                 } else {
1493                         output(o, 2, "Adding %s", path);
1494                         update_file(o, 1, sha, mode, path);
1495                 }
1496         } else {
1497                 entry->processed = 0;
1498                 return 1; /* not handled; assume clean until processed */
1499         }
1500
1501         return clean_merge;
1502 }
1503
1504 int merge_trees(struct merge_options *o,
1505                 struct tree *head,
1506                 struct tree *merge,
1507                 struct tree *common,
1508                 struct tree **result)
1509 {
1510         int code, clean;
1511
1512         if (o->subtree_shift) {
1513                 merge = shift_tree_object(head, merge, o->subtree_shift);
1514                 common = shift_tree_object(head, common, o->subtree_shift);
1515         }
1516
1517         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1518                 output(o, 0, "Already up-to-date!");
1519                 *result = head;
1520                 return 1;
1521         }
1522
1523         code = git_merge_trees(o->call_depth, common, head, merge);
1524
1525         if (code != 0) {
1526                 if (show(o, 4) || o->call_depth)
1527                         die("merging of trees %s and %s failed",
1528                             sha1_to_hex(head->object.sha1),
1529                             sha1_to_hex(merge->object.sha1));
1530                 else
1531                         exit(128);
1532         }
1533
1534         if (unmerged_cache()) {
1535                 struct string_list *entries, *re_head, *re_merge;
1536                 int i;
1537                 string_list_clear(&o->current_file_set, 1);
1538                 string_list_clear(&o->current_directory_set, 1);
1539                 get_files_dirs(o, head);
1540                 get_files_dirs(o, merge);
1541
1542                 entries = get_unmerged();
1543                 make_room_for_directories_of_df_conflicts(o, entries);
1544                 re_head  = get_renames(o, head, common, head, merge, entries);
1545                 re_merge = get_renames(o, merge, common, head, merge, entries);
1546                 clean = process_renames(o, re_head, re_merge);
1547                 for (i = 0; i < entries->nr; i++) {
1548                         const char *path = entries->items[i].string;
1549                         struct stage_data *e = entries->items[i].util;
1550                         if (!e->processed
1551                                 && !process_entry(o, path, e))
1552                                 clean = 0;
1553                 }
1554                 for (i = 0; i < entries->nr; i++) {
1555                         const char *path = entries->items[i].string;
1556                         struct stage_data *e = entries->items[i].util;
1557                         if (!e->processed
1558                                 && !process_df_entry(o, path, e))
1559                                 clean = 0;
1560                 }
1561                 for (i = 0; i < entries->nr; i++) {
1562                         struct stage_data *e = entries->items[i].util;
1563                         if (!e->processed)
1564                                 die("Unprocessed path??? %s",
1565                                     entries->items[i].string);
1566                 }
1567
1568                 string_list_clear(re_merge, 0);
1569                 string_list_clear(re_head, 0);
1570                 string_list_clear(entries, 1);
1571
1572         }
1573         else
1574                 clean = 1;
1575
1576         if (o->call_depth)
1577                 *result = write_tree_from_memory(o);
1578
1579         return clean;
1580 }
1581
1582 static struct commit_list *reverse_commit_list(struct commit_list *list)
1583 {
1584         struct commit_list *next = NULL, *current, *backup;
1585         for (current = list; current; current = backup) {
1586                 backup = current->next;
1587                 current->next = next;
1588                 next = current;
1589         }
1590         return next;
1591 }
1592
1593 /*
1594  * Merge the commits h1 and h2, return the resulting virtual
1595  * commit object and a flag indicating the cleanness of the merge.
1596  */
1597 int merge_recursive(struct merge_options *o,
1598                     struct commit *h1,
1599                     struct commit *h2,
1600                     struct commit_list *ca,
1601                     struct commit **result)
1602 {
1603         struct commit_list *iter;
1604         struct commit *merged_common_ancestors;
1605         struct tree *mrtree = mrtree;
1606         int clean;
1607
1608         if (show(o, 4)) {
1609                 output(o, 4, "Merging:");
1610                 output_commit_title(o, h1);
1611                 output_commit_title(o, h2);
1612         }
1613
1614         if (!ca) {
1615                 ca = get_merge_bases(h1, h2, 1);
1616                 ca = reverse_commit_list(ca);
1617         }
1618
1619         if (show(o, 5)) {
1620                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1621                 for (iter = ca; iter; iter = iter->next)
1622                         output_commit_title(o, iter->item);
1623         }
1624
1625         merged_common_ancestors = pop_commit(&ca);
1626         if (merged_common_ancestors == NULL) {
1627                 /* if there is no common ancestor, make an empty tree */
1628                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1629
1630                 tree->object.parsed = 1;
1631                 tree->object.type = OBJ_TREE;
1632                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1633                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1634         }
1635
1636         for (iter = ca; iter; iter = iter->next) {
1637                 const char *saved_b1, *saved_b2;
1638                 o->call_depth++;
1639                 /*
1640                  * When the merge fails, the result contains files
1641                  * with conflict markers. The cleanness flag is
1642                  * ignored, it was never actually used, as result of
1643                  * merge_trees has always overwritten it: the committed
1644                  * "conflicts" were already resolved.
1645                  */
1646                 discard_cache();
1647                 saved_b1 = o->branch1;
1648                 saved_b2 = o->branch2;
1649                 o->branch1 = "Temporary merge branch 1";
1650                 o->branch2 = "Temporary merge branch 2";
1651                 merge_recursive(o, merged_common_ancestors, iter->item,
1652                                 NULL, &merged_common_ancestors);
1653                 o->branch1 = saved_b1;
1654                 o->branch2 = saved_b2;
1655                 o->call_depth--;
1656
1657                 if (!merged_common_ancestors)
1658                         die("merge returned no commit");
1659         }
1660
1661         discard_cache();
1662         if (!o->call_depth)
1663                 read_cache();
1664
1665         o->ancestor = "merged common ancestors";
1666         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1667                             &mrtree);
1668
1669         if (o->call_depth) {
1670                 *result = make_virtual_commit(mrtree, "merged tree");
1671                 commit_list_insert(h1, &(*result)->parents);
1672                 commit_list_insert(h2, &(*result)->parents->next);
1673         }
1674         flush_output(o);
1675         if (o->needed_rename_limit)
1676                 warning(rename_limit_advice, o->needed_rename_limit);
1677         return clean;
1678 }
1679
1680 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1681 {
1682         struct object *object;
1683
1684         object = deref_tag(parse_object(sha1), name, strlen(name));
1685         if (!object)
1686                 return NULL;
1687         if (object->type == OBJ_TREE)
1688                 return make_virtual_commit((struct tree*)object, name);
1689         if (object->type != OBJ_COMMIT)
1690                 return NULL;
1691         if (parse_commit((struct commit *)object))
1692                 return NULL;
1693         return (struct commit *)object;
1694 }
1695
1696 int merge_recursive_generic(struct merge_options *o,
1697                             const unsigned char *head,
1698                             const unsigned char *merge,
1699                             int num_base_list,
1700                             const unsigned char **base_list,
1701                             struct commit **result)
1702 {
1703         int clean, index_fd;
1704         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1705         struct commit *head_commit = get_ref(head, o->branch1);
1706         struct commit *next_commit = get_ref(merge, o->branch2);
1707         struct commit_list *ca = NULL;
1708
1709         if (base_list) {
1710                 int i;
1711                 for (i = 0; i < num_base_list; ++i) {
1712                         struct commit *base;
1713                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1714                                 return error("Could not parse object '%s'",
1715                                         sha1_to_hex(base_list[i]));
1716                         commit_list_insert(base, &ca);
1717                 }
1718         }
1719
1720         index_fd = hold_locked_index(lock, 1);
1721         clean = merge_recursive(o, head_commit, next_commit, ca,
1722                         result);
1723         if (active_cache_changed &&
1724                         (write_cache(index_fd, active_cache, active_nr) ||
1725                          commit_locked_index(lock)))
1726                 return error("Unable to write index.");
1727
1728         return clean ? 0 : 1;
1729 }
1730
1731 static int merge_recursive_config(const char *var, const char *value, void *cb)
1732 {
1733         struct merge_options *o = cb;
1734         if (!strcasecmp(var, "merge.verbosity")) {
1735                 o->verbosity = git_config_int(var, value);
1736                 return 0;
1737         }
1738         if (!strcasecmp(var, "diff.renamelimit")) {
1739                 o->diff_rename_limit = git_config_int(var, value);
1740                 return 0;
1741         }
1742         if (!strcasecmp(var, "merge.renamelimit")) {
1743                 o->merge_rename_limit = git_config_int(var, value);
1744                 return 0;
1745         }
1746         return git_xmerge_config(var, value, cb);
1747 }
1748
1749 void init_merge_options(struct merge_options *o)
1750 {
1751         memset(o, 0, sizeof(struct merge_options));
1752         o->verbosity = 2;
1753         o->buffer_output = 1;
1754         o->diff_rename_limit = -1;
1755         o->merge_rename_limit = -1;
1756         o->renormalize = 0;
1757         git_config(merge_recursive_config, o);
1758         if (getenv("GIT_MERGE_VERBOSITY"))
1759                 o->verbosity =
1760                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1761         if (o->verbosity >= 5)
1762                 o->buffer_output = 0;
1763         strbuf_init(&o->obuf, 0);
1764         memset(&o->current_file_set, 0, sizeof(struct string_list));
1765         o->current_file_set.strdup_strings = 1;
1766         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1767         o->current_directory_set.strdup_strings = 1;
1768 }
1769
1770 int parse_merge_opt(struct merge_options *o, const char *s)
1771 {
1772         if (!s || !*s)
1773                 return -1;
1774         if (!strcmp(s, "ours"))
1775                 o->recursive_variant = MERGE_RECURSIVE_OURS;
1776         else if (!strcmp(s, "theirs"))
1777                 o->recursive_variant = MERGE_RECURSIVE_THEIRS;
1778         else if (!strcmp(s, "subtree"))
1779                 o->subtree_shift = "";
1780         else if (!prefixcmp(s, "subtree="))
1781                 o->subtree_shift = s + strlen("subtree=");
1782         else if (!strcmp(s, "patience"))
1783                 o->xdl_opts |= XDF_PATIENCE_DIFF;
1784         else if (!strcmp(s, "ignore-space-change"))
1785                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
1786         else if (!strcmp(s, "ignore-all-space"))
1787                 o->xdl_opts |= XDF_IGNORE_WHITESPACE;
1788         else if (!strcmp(s, "ignore-space-at-eol"))
1789                 o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
1790         else if (!strcmp(s, "renormalize"))
1791                 o->renormalize = 1;
1792         else if (!strcmp(s, "no-renormalize"))
1793                 o->renormalize = 0;
1794         else if (!prefixcmp(s, "rename-threshold=")) {
1795                 const char *score = s + strlen("rename-threshold=");
1796                 if ((o->rename_score = parse_rename_score(&score)) == -1 || *score != 0)
1797                         return -1;
1798         }
1799         else
1800                 return -1;
1801         return 0;
1802 }