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

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