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