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 /*
  67  * Since we want to write the index eventually, we cannot reuse the index
  68  * for these (temporary) data.
  69  */
  70 struct stage_data
  71 {
  72         struct
  73         {
  74                 unsigned mode;
  75                 unsigned char sha[20];
  76         } stages[4];
  77         unsigned processed:1;
  78 };
  79
  80 static int show(struct merge_options *o, int v)
  81 {
  82         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  83 }
  84
  85 static void flush_output(struct merge_options *o)
  86 {
  87         if (o->obuf.len) {
  88                 fputs(o->obuf.buf, stdout);
  89                 strbuf_reset(&o->obuf);
  90         }
  91 }
  92
  93 __attribute__((format (printf, 3, 4)))
  94 static void output(struct merge_options *o, int v, const char *fmt, ...)
  95 {
  96         int len;
  97         va_list ap;
  98
  99         if (!show(o, v))
 100                 return;
 101
 102         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 103         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 104         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 105
 106         va_start(ap, fmt);
 107         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 108         va_end(ap);
 109
 110         if (len < 0)
 111                 len = 0;
 112         if (len >= strbuf_avail(&o->obuf)) {
 113                 strbuf_grow(&o->obuf, len + 2);
 114                 va_start(ap, fmt);
 115                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 116                 va_end(ap);
 117                 if (len >= strbuf_avail(&o->obuf)) {
 118                         die("this should not happen, your snprintf is broken");
 119                 }
 120         }
 121         strbuf_setlen(&o->obuf, o->obuf.len + len);
 122         strbuf_add(&o->obuf, "\n", 1);
 123         if (!o->buffer_output)
 124                 flush_output(o);
 125 }
 126
 127 static void output_commit_title(struct merge_options *o, struct commit *commit)
 128 {
 129         int i;
 130         flush_output(o);
 131         for (i = o->call_depth; i--;)
 132                 fputs("  ", stdout);
 133         if (commit->util)
 134                 printf("virtual %s\n", (char *)commit->util);
 135         else {
 136                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 137                 if (parse_commit(commit) != 0)
 138                         printf("(bad commit)\n");
 139                 else {
 140                         const char *title;
 141                         int len = find_commit_subject(commit->buffer, &title);
 142                         if (len)
 143                                 printf("%.*s\n", len, title);
 144                 }
 145         }
 146 }
 147
 148 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 149                 const char *path, int stage, int refresh, int options)
 150 {
 151         struct cache_entry *ce;
 152         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 153         if (!ce)
 154                 return error("addinfo_cache failed for path '%s'", path);
 155         return add_cache_entry(ce, options);
 156 }
 157
 158 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 159 {
 160         parse_tree(tree);
 161         init_tree_desc(desc, tree->buffer, tree->size);
 162 }
 163
 164 static int git_merge_trees(int index_only,
 165                            struct tree *common,
 166                            struct tree *head,
 167                            struct tree *merge)
 168 {
 169         int rc;
 170         struct tree_desc t[3];
 171         struct unpack_trees_options opts;
 172
 173         memset(&opts, 0, sizeof(opts));
 174         if (index_only)
 175                 opts.index_only = 1;
 176         else
 177                 opts.update = 1;
 178         opts.merge = 1;
 179         opts.head_idx = 2;
 180         opts.fn = threeway_merge;
 181         opts.src_index = &the_index;
 182         opts.dst_index = &the_index;
 183         setup_unpack_trees_porcelain(&opts, "merge");
 184
 185         init_tree_desc_from_tree(t+0, common);
 186         init_tree_desc_from_tree(t+1, head);
 187         init_tree_desc_from_tree(t+2, merge);
 188
 189         rc = unpack_trees(3, t, &opts);
 190         cache_tree_free(&active_cache_tree);
 191         return rc;
 192 }
 193
 194 struct tree *write_tree_from_memory(struct merge_options *o)
 195 {
 196         struct tree *result = NULL;
 197
 198         if (unmerged_cache()) {
 199                 int i;
 200                 fprintf(stderr, "BUG: There are unmerged index entries:\n");
 201                 for (i = 0; i < active_nr; i++) {
 202                         struct cache_entry *ce = active_cache[i];
 203                         if (ce_stage(ce))
 204                                 fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 205                                         (int)ce_namelen(ce), ce->name);
 206                 }
 207                 die("Bug in merge-recursive.c");
 208         }
 209
 210         if (!active_cache_tree)
 211                 active_cache_tree = cache_tree();
 212
 213         if (!cache_tree_fully_valid(active_cache_tree) &&
 214             cache_tree_update(active_cache_tree,
 215                               active_cache, active_nr, 0, 0) < 0)
 216                 die("error building trees");
 217
 218         result = lookup_tree(active_cache_tree->sha1);
 219
 220         return result;
 221 }
 222
 223 static int save_files_dirs(const unsigned char *sha1,
 224                 const char *base, int baselen, const char *path,
 225                 unsigned int mode, int stage, void *context)
 226 {
 227         int len = strlen(path);
 228         char *newpath = xmalloc(baselen + len + 1);
 229         struct merge_options *o = context;
 230
 231         memcpy(newpath, base, baselen);
 232         memcpy(newpath + baselen, path, len);
 233         newpath[baselen + len] = '\0';
 234
 235         if (S_ISDIR(mode))
 236                 string_list_insert(&o->current_directory_set, newpath);
 237         else
 238                 string_list_insert(&o->current_file_set, newpath);
 239         free(newpath);
 240
 241         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 242 }
 243
 244 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 245 {
 246         int n;
 247         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 248                 return 0;
 249         n = o->current_file_set.nr + o->current_directory_set.nr;
 250         return n;
 251 }
 252
 253 /*
 254  * Returns an index_entry instance which doesn't have to correspond to
 255  * a real cache entry in Git's index.
 256  */
 257 static struct stage_data *insert_stage_data(const char *path,
 258                 struct tree *o, struct tree *a, struct tree *b,
 259                 struct string_list *entries)
 260 {
 261         struct string_list_item *item;
 262         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 263         get_tree_entry(o->object.sha1, path,
 264                         e->stages[1].sha, &e->stages[1].mode);
 265         get_tree_entry(a->object.sha1, path,
 266                         e->stages[2].sha, &e->stages[2].mode);
 267         get_tree_entry(b->object.sha1, path,
 268                         e->stages[3].sha, &e->stages[3].mode);
 269         item = string_list_insert(entries, path);
 270         item->util = e;
 271         return e;
 272 }
 273
 274 /*
 275  * Create a dictionary mapping file names to stage_data objects. The
 276  * dictionary contains one entry for every path with a non-zero stage entry.
 277  */
 278 static struct string_list *get_unmerged(void)
 279 {
 280         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 281         int i;
 282
 283         unmerged->strdup_strings = 1;
 284
 285         for (i = 0; i < active_nr; i++) {
 286                 struct string_list_item *item;
 287                 struct stage_data *e;
 288                 struct cache_entry *ce = active_cache[i];
 289                 if (!ce_stage(ce))
 290                         continue;
 291
 292                 item = string_list_lookup(unmerged, ce->name);
 293                 if (!item) {
 294                         item = string_list_insert(unmerged, ce->name);
 295                         item->util = xcalloc(1, sizeof(struct stage_data));
 296                 }
 297                 e = item->util;
 298                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 299                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 300         }
 301
 302         return unmerged;
 303 }
 304
 305 struct rename
 306 {
 307         struct diff_filepair *pair;
 308         struct stage_data *src_entry;
 309         struct stage_data *dst_entry;
 310         unsigned processed:1;
 311 };
 312
 313 /*
 314  * Get information of all renames which occurred between 'o_tree' and
 315  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 316  * 'b_tree') to be able to associate the correct cache entries with
 317  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 318  */
 319 static struct string_list *get_renames(struct merge_options *o,
 320                                        struct tree *tree,
 321                                        struct tree *o_tree,
 322                                        struct tree *a_tree,
 323                                        struct tree *b_tree,
 324                                        struct string_list *entries)
 325 {
 326         int i;
 327         struct string_list *renames;
 328         struct diff_options opts;
 329
 330         renames = xcalloc(1, sizeof(struct string_list));
 331         diff_setup(&opts);
 332         DIFF_OPT_SET(&opts, RECURSIVE);
 333         opts.detect_rename = DIFF_DETECT_RENAME;
 334         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 335                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 336                             500;
 337         opts.warn_on_too_large_rename = 1;
 338         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 339         if (diff_setup_done(&opts) < 0)
 340                 die("diff setup failed");
 341         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 342         diffcore_std(&opts);
 343         for (i = 0; i < diff_queued_diff.nr; ++i) {
 344                 struct string_list_item *item;
 345                 struct rename *re;
 346                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 347                 if (pair->status != 'R') {
 348                         diff_free_filepair(pair);
 349                         continue;
 350                 }
 351                 re = xmalloc(sizeof(*re));
 352                 re->processed = 0;
 353                 re->pair = pair;
 354                 item = string_list_lookup(entries, re->pair->one->path);
 355                 if (!item)
 356                         re->src_entry = insert_stage_data(re->pair->one->path,
 357                                         o_tree, a_tree, b_tree, entries);
 358                 else
 359                         re->src_entry = item->util;
 360
 361                 item = string_list_lookup(entries, re->pair->two->path);
 362                 if (!item)
 363                         re->dst_entry = insert_stage_data(re->pair->two->path,
 364                                         o_tree, a_tree, b_tree, entries);
 365                 else
 366                         re->dst_entry = item->util;
 367                 item = string_list_insert(renames, pair->one->path);
 368                 item->util = re;
 369         }
 370         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 371         diff_queued_diff.nr = 0;
 372         diff_flush(&opts);
 373         return renames;
 374 }
 375
 376 static int update_stages(const char *path, struct diff_filespec *o,
 377                          struct diff_filespec *a, struct diff_filespec *b,
 378                          int clear)
 379 {
 380         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 381         if (clear)
 382                 if (remove_file_from_cache(path))
 383                         return -1;
 384         if (o)
 385                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 386                         return -1;
 387         if (a)
 388                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 389                         return -1;
 390         if (b)
 391                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 392                         return -1;
 393         return 0;
 394 }
 395
 396 static int remove_file(struct merge_options *o, int clean,
 397                        const char *path, int no_wd)
 398 {
 399         int update_cache = o->call_depth || clean;
 400         int update_working_directory = !o->call_depth && !no_wd;
 401
 402         if (update_cache) {
 403                 if (remove_file_from_cache(path))
 404                         return -1;
 405         }
 406         if (update_working_directory) {
 407                 if (remove_path(path))
 408                         return -1;
 409         }
 410         return 0;
 411 }
 412
 413 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 414 {
 415         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 416         int suffix = 0;
 417         struct stat st;
 418         char *p = newpath + strlen(path);
 419         strcpy(newpath, path);
 420         *(p++) = '~';
 421         strcpy(p, branch);
 422         for (; *p; ++p)
 423                 if ('/' == *p)
 424                         *p = '_';
 425         while (string_list_has_string(&o->current_file_set, newpath) ||
 426                string_list_has_string(&o->current_directory_set, newpath) ||
 427                lstat(newpath, &st) == 0)
 428                 sprintf(p, "_%d", suffix++);
 429
 430         string_list_insert(&o->current_file_set, newpath);
 431         return newpath;
 432 }
 433
 434 static void flush_buffer(int fd, const char *buf, unsigned long size)
 435 {
 436         while (size > 0) {
 437                 long ret = write_in_full(fd, buf, size);
 438                 if (ret < 0) {
 439                         /* Ignore epipe */
 440                         if (errno == EPIPE)
 441                                 break;
 442                         die_errno("merge-recursive");
 443                 } else if (!ret) {
 444                         die("merge-recursive: disk full?");
 445                 }
 446                 size -= ret;
 447                 buf += ret;
 448         }
 449 }
 450
 451 static int would_lose_untracked(const char *path)
 452 {
 453         int pos = cache_name_pos(path, strlen(path));
 454
 455         if (pos < 0)
 456                 pos = -1 - pos;
 457         while (pos < active_nr &&
 458                !strcmp(path, active_cache[pos]->name)) {
 459                 /*
 460                  * If stage #0, it is definitely tracked.
 461                  * If it has stage #2 then it was tracked
 462                  * before this merge started.  All other
 463                  * cases the path was not tracked.
 464                  */
 465                 switch (ce_stage(active_cache[pos])) {
 466                 case 0:
 467                 case 2:
 468                         return 0;
 469                 }
 470                 pos++;
 471         }
 472         return file_exists(path);
 473 }
 474
 475 static int make_room_for_path(const char *path)
 476 {
 477         int status;
 478         const char *msg = "failed to create path '%s'%s";
 479
 480         status = safe_create_leading_directories_const(path);
 481         if (status) {
 482                 if (status == -3) {
 483                         /* something else exists */
 484                         error(msg, path, ": perhaps a D/F conflict?");
 485                         return -1;
 486                 }
 487                 die(msg, path, "");
 488         }
 489
 490         /*
 491          * Do not unlink a file in the work tree if we are not
 492          * tracking it.
 493          */
 494         if (would_lose_untracked(path))
 495                 return error("refusing to lose untracked file at '%s'",
 496                              path);
 497
 498         /* Successful unlink is good.. */
 499         if (!unlink(path))
 500                 return 0;
 501         /* .. and so is no existing file */
 502         if (errno == ENOENT)
 503                 return 0;
 504         /* .. but not some other error (who really cares what?) */
 505         return error(msg, path, ": perhaps a D/F conflict?");
 506 }
 507
 508 static void update_file_flags(struct merge_options *o,
 509                               const unsigned char *sha,
 510                               unsigned mode,
 511                               const char *path,
 512                               int update_cache,
 513                               int update_wd)
 514 {
 515         if (o->call_depth)
 516                 update_wd = 0;
 517
 518         if (update_wd) {
 519                 enum object_type type;
 520                 void *buf;
 521                 unsigned long size;
 522
 523                 if (S_ISGITLINK(mode)) {
 524                         /*
 525                          * We may later decide to recursively descend into
 526                          * the submodule directory and update its index
 527                          * and/or work tree, but we do not do that now.
 528                          */
 529                         update_wd = 0;
 530                         goto update_index;
 531                 }
 532
 533                 buf = read_sha1_file(sha, &type, &size);
 534                 if (!buf)
 535                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 536                 if (type != OBJ_BLOB)
 537                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 538                 if (S_ISREG(mode)) {
 539                         struct strbuf strbuf = STRBUF_INIT;
 540                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 541                                 free(buf);
 542                                 size = strbuf.len;
 543                                 buf = strbuf_detach(&strbuf, NULL);
 544                         }
 545                 }
 546
 547                 if (make_room_for_path(path) < 0) {
 548                         update_wd = 0;
 549                         free(buf);
 550                         goto update_index;
 551                 }
 552                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 553                         int fd;
 554                         if (mode & 0100)
 555                                 mode = 0777;
 556                         else
 557                                 mode = 0666;
 558                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 559                         if (fd < 0)
 560                                 die_errno("failed to open '%s'", path);
 561                         flush_buffer(fd, buf, size);
 562                         close(fd);
 563                 } else if (S_ISLNK(mode)) {
 564                         char *lnk = xmemdupz(buf, size);
 565                         safe_create_leading_directories_const(path);
 566                         unlink(path);
 567                         if (symlink(lnk, path))
 568                                 die_errno("failed to symlink '%s'", path);
 569                         free(lnk);
 570                 } else
 571                         die("do not know what to do with %06o %s '%s'",
 572                             mode, sha1_to_hex(sha), path);
 573                 free(buf);
 574         }
 575  update_index:
 576         if (update_cache)
 577                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 578 }
 579
 580 static void update_file(struct merge_options *o,
 581                         int clean,
 582                         const unsigned char *sha,
 583                         unsigned mode,
 584                         const char *path)
 585 {
 586         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 587 }
 588
 589 /* Low level file merging, update and removal */
 590
 591 struct merge_file_info
 592 {
 593         unsigned char sha[20];
 594         unsigned mode;
 595         unsigned clean:1,
 596                  merge:1;
 597 };
 598
 599 static int merge_3way(struct merge_options *o,
 600                       mmbuffer_t *result_buf,
 601                       struct diff_filespec *one,
 602                       struct diff_filespec *a,
 603                       struct diff_filespec *b,
 604                       const char *branch1,
 605                       const char *branch2)
 606 {
 607         mmfile_t orig, src1, src2;
 608         char *base_name, *name1, *name2;
 609         int merge_status;
 610         int favor;
 611
 612         if (o->call_depth)
 613                 favor = 0;
 614         else {
 615                 switch (o->recursive_variant) {
 616                 case MERGE_RECURSIVE_OURS:
 617                         favor = XDL_MERGE_FAVOR_OURS;
 618                         break;
 619                 case MERGE_RECURSIVE_THEIRS:
 620                         favor = XDL_MERGE_FAVOR_THEIRS;
 621                         break;
 622                 default:
 623                         favor = 0;
 624                         break;
 625                 }
 626         }
 627
 628         if (strcmp(a->path, b->path) ||
 629             (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 630                 base_name = o->ancestor == NULL ? NULL :
 631                         xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 632                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 633                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 634         } else {
 635                 base_name = o->ancestor == NULL ? NULL :
 636                         xstrdup(mkpath("%s", o->ancestor));
 637                 name1 = xstrdup(mkpath("%s", branch1));
 638                 name2 = xstrdup(mkpath("%s", branch2));
 639         }
 640
 641         read_mmblob(&orig, one->sha1);
 642         read_mmblob(&src1, a->sha1);
 643         read_mmblob(&src2, b->sha1);
 644
 645         merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 646                                 &src1, name1, &src2, name2,
 647                                 ((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
 648                                  (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
 649                                  create_ll_flag(favor)));
 650
 651         free(name1);
 652         free(name2);
 653         free(orig.ptr);
 654         free(src1.ptr);
 655         free(src2.ptr);
 656         return merge_status;
 657 }
 658
 659 static struct merge_file_info merge_file(struct merge_options *o,
 660                                          struct diff_filespec *one,
 661                                          struct diff_filespec *a,
 662                                          struct diff_filespec *b,
 663                                          const char *branch1,
 664                                          const char *branch2)
 665 {
 666         struct merge_file_info result;
 667         result.merge = 0;
 668         result.clean = 1;
 669
 670         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 671                 result.clean = 0;
 672                 if (S_ISREG(a->mode)) {
 673                         result.mode = a->mode;
 674                         hashcpy(result.sha, a->sha1);
 675                 } else {
 676                         result.mode = b->mode;
 677                         hashcpy(result.sha, b->sha1);
 678                 }
 679         } else {
 680                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 681                         result.merge = 1;
 682
 683                 /*
 684                  * Merge modes
 685                  */
 686                 if (a->mode == b->mode || a->mode == one->mode)
 687                         result.mode = b->mode;
 688                 else {
 689                         result.mode = a->mode;
 690                         if (b->mode != one->mode) {
 691                                 result.clean = 0;
 692                                 result.merge = 1;
 693                         }
 694                 }
 695
 696                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 697                         hashcpy(result.sha, b->sha1);
 698                 else if (sha_eq(b->sha1, one->sha1))
 699                         hashcpy(result.sha, a->sha1);
 700                 else if (S_ISREG(a->mode)) {
 701                         mmbuffer_t result_buf;
 702                         int merge_status;
 703
 704                         merge_status = merge_3way(o, &result_buf, one, a, b,
 705                                                   branch1, branch2);
 706
 707                         if ((merge_status < 0) || !result_buf.ptr)
 708                                 die("Failed to execute internal merge");
 709
 710                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 711                                             blob_type, result.sha))
 712                                 die("Unable to add %s to database",
 713                                     a->path);
 714
 715                         free(result_buf.ptr);
 716                         result.clean = (merge_status == 0);
 717                 } else if (S_ISGITLINK(a->mode)) {
 718                         result.clean = merge_submodule(result.sha, one->path, one->sha1,
 719                                                        a->sha1, b->sha1);
 720                 } else if (S_ISLNK(a->mode)) {
 721                         hashcpy(result.sha, a->sha1);
 722
 723                         if (!sha_eq(a->sha1, b->sha1))
 724                                 result.clean = 0;
 725                 } else {
 726                         die("unsupported object type in the tree");
 727                 }
 728         }
 729
 730         return result;
 731 }
 732
 733 static void conflict_rename_delete(struct merge_options *o,
 734                                    struct diff_filepair *pair,
 735                                    const char *rename_branch,
 736                                    const char *other_branch)
 737 {
 738         char *dest_name = pair->two->path;
 739
 740         output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 741                "and deleted in %s",
 742                pair->one->path, pair->two->path, rename_branch,
 743                other_branch);
 744         if (!o->call_depth)
 745                 update_stages(dest_name, NULL,
 746                               rename_branch == o->branch1 ? pair->two : NULL,
 747                               rename_branch == o->branch1 ? NULL : pair->two,
 748                               1);
 749         update_file(o, 0, pair->two->sha1, pair->two->mode, dest_name);
 750 }
 751
 752 static void conflict_rename_rename_1to2(struct merge_options *o,
 753                                         struct rename *ren1,
 754                                         const char *branch1,
 755                                         struct rename *ren2,
 756                                         const char *branch2)
 757 {
 758         /* One file was renamed in both branches, but to different names. */
 759         char *del[2];
 760         int delp = 0;
 761         const char *ren1_dst = ren1->pair->two->path;
 762         const char *ren2_dst = ren2->pair->two->path;
 763         const char *dst_name1 = ren1_dst;
 764         const char *dst_name2 = ren2_dst;
 765         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 766                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 767                 output(o, 1, "%s is a directory in %s adding as %s instead",
 768                        ren1_dst, branch2, dst_name1);
 769                 remove_file(o, 0, ren1_dst, 0);
 770         }
 771         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 772                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 773                 output(o, 1, "%s is a directory in %s adding as %s instead",
 774                        ren2_dst, branch1, dst_name2);
 775                 remove_file(o, 0, ren2_dst, 0);
 776         }
 777         if (o->call_depth) {
 778                 remove_file_from_cache(dst_name1);
 779                 remove_file_from_cache(dst_name2);
 780                 /*
 781                  * Uncomment to leave the conflicting names in the resulting tree
 782                  *
 783                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 784                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 785                  */
 786         } else {
 787                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 788                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 789         }
 790         while (delp--)
 791                 free(del[delp]);
 792 }
 793
 794 static void conflict_rename_rename_2to1(struct merge_options *o,
 795                                         struct rename *ren1,
 796                                         const char *branch1,
 797                                         struct rename *ren2,
 798                                         const char *branch2)
 799 {
 800         /* Two files were renamed to the same thing. */
 801         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 802         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 803         output(o, 1, "Renaming %s to %s and %s to %s instead",
 804                ren1->pair->one->path, new_path1,
 805                ren2->pair->one->path, new_path2);
 806         remove_file(o, 0, ren1->pair->two->path, 0);
 807         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 808         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 809         free(new_path2);
 810         free(new_path1);
 811 }
 812
 813 static int process_renames(struct merge_options *o,
 814                            struct string_list *a_renames,
 815                            struct string_list *b_renames)
 816 {
 817         int clean_merge = 1, i, j;
 818         struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 819         struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 820         const struct rename *sre;
 821
 822         for (i = 0; i < a_renames->nr; i++) {
 823                 sre = a_renames->items[i].util;
 824                 string_list_insert(&a_by_dst, sre->pair->two->path)->util
 825                         = sre->dst_entry;
 826         }
 827         for (i = 0; i < b_renames->nr; i++) {
 828                 sre = b_renames->items[i].util;
 829                 string_list_insert(&b_by_dst, sre->pair->two->path)->util
 830                         = sre->dst_entry;
 831         }
 832
 833         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 834                 char *src;
 835                 struct string_list *renames1, *renames2Dst;
 836                 struct rename *ren1 = NULL, *ren2 = NULL;
 837                 const char *branch1, *branch2;
 838                 const char *ren1_src, *ren1_dst;
 839
 840                 if (i >= a_renames->nr) {
 841                         ren2 = b_renames->items[j++].util;
 842                 } else if (j >= b_renames->nr) {
 843                         ren1 = a_renames->items[i++].util;
 844                 } else {
 845                         int compare = strcmp(a_renames->items[i].string,
 846                                              b_renames->items[j].string);
 847                         if (compare <= 0)
 848                                 ren1 = a_renames->items[i++].util;
 849                         if (compare >= 0)
 850                                 ren2 = b_renames->items[j++].util;
 851                 }
 852
 853                 /* TODO: refactor, so that 1/2 are not needed */
 854                 if (ren1) {
 855                         renames1 = a_renames;
 856                         renames2Dst = &b_by_dst;
 857                         branch1 = o->branch1;
 858                         branch2 = o->branch2;
 859                 } else {
 860                         struct rename *tmp;
 861                         renames1 = b_renames;
 862                         renames2Dst = &a_by_dst;
 863                         branch1 = o->branch2;
 864                         branch2 = o->branch1;
 865                         tmp = ren2;
 866                         ren2 = ren1;
 867                         ren1 = tmp;
 868                 }
 869                 src = ren1->pair->one->path;
 870
 871                 ren1->dst_entry->processed = 1;
 872                 ren1->src_entry->processed = 1;
 873
 874                 if (ren1->processed)
 875                         continue;
 876                 ren1->processed = 1;
 877
 878                 ren1_src = ren1->pair->one->path;
 879                 ren1_dst = ren1->pair->two->path;
 880
 881                 if (ren2) {
 882                         const char *ren2_src = ren2->pair->one->path;
 883                         const char *ren2_dst = ren2->pair->two->path;
 884                         /* Renamed in 1 and renamed in 2 */
 885                         if (strcmp(ren1_src, ren2_src) != 0)
 886                                 die("ren1.src != ren2.src");
 887                         ren2->dst_entry->processed = 1;
 888                         ren2->processed = 1;
 889                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 890                                 clean_merge = 0;
 891                                 output(o, 1, "CONFLICT (rename/rename): "
 892                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 893                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 894                                        src, ren1_dst, branch1,
 895                                        src, ren2_dst, branch2,
 896                                        o->call_depth ? " (left unresolved)": "");
 897                                 if (o->call_depth) {
 898                                         remove_file_from_cache(src);
 899                                         update_file(o, 0, ren1->pair->one->sha1,
 900                                                     ren1->pair->one->mode, src);
 901                                 }
 902                                 conflict_rename_rename_1to2(o, ren1, branch1, ren2, branch2);
 903                         } else {
 904                                 struct merge_file_info mfi;
 905                                 remove_file(o, 1, ren1_src, 1);
 906                                 mfi = merge_file(o,
 907                                                  ren1->pair->one,
 908                                                  ren1->pair->two,
 909                                                  ren2->pair->two,
 910                                                  branch1,
 911                                                  branch2);
 912                                 if (mfi.merge || !mfi.clean)
 913                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 914
 915                                 if (mfi.merge)
 916                                         output(o, 2, "Auto-merging %s", ren1_dst);
 917
 918                                 if (!mfi.clean) {
 919                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 920                                                ren1_dst);
 921                                         clean_merge = 0;
 922
 923                                         if (!o->call_depth)
 924                                                 update_stages(ren1_dst,
 925                                                               ren1->pair->one,
 926                                                               ren1->pair->two,
 927                                                               ren2->pair->two,
 928                                                               1 /* clear */);
 929                                 }
 930                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 931                         }
 932                 } else {
 933                         /* Renamed in 1, maybe changed in 2 */
 934                         struct string_list_item *item;
 935                         /* we only use sha1 and mode of these */
 936                         struct diff_filespec src_other, dst_other;
 937                         int try_merge;
 938
 939                         /*
 940                          * unpack_trees loads entries from common-commit
 941                          * into stage 1, from head-commit into stage 2, and
 942                          * from merge-commit into stage 3.  We keep track
 943                          * of which side corresponds to the rename.
 944                          */
 945                         int renamed_stage = a_renames == renames1 ? 2 : 3;
 946                         int other_stage =   a_renames == renames1 ? 3 : 2;
 947
 948                         remove_file(o, 1, ren1_src, o->call_depth || renamed_stage == 2);
 949
 950                         hashcpy(src_other.sha1, ren1->src_entry->stages[other_stage].sha);
 951                         src_other.mode = ren1->src_entry->stages[other_stage].mode;
 952                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[other_stage].sha);
 953                         dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
 954                         try_merge = 0;
 955
 956                         if (sha_eq(src_other.sha1, null_sha1)) {
 957                                 clean_merge = 0;
 958                                 conflict_rename_delete(o, ren1->pair, branch1, branch2);
 959                         } else if ((dst_other.mode == ren1->pair->two->mode) &&
 960                                    sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
 961                                 /* Added file on the other side
 962                                    identical to the file being
 963                                    renamed: clean merge */
 964                                 update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 965                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 966                                 const char *new_path;
 967                                 clean_merge = 0;
 968                                 try_merge = 1;
 969                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 970                                        "%s added in %s",
 971                                        ren1_src, ren1_dst, branch1,
 972                                        ren1_dst, branch2);
 973                                 if (o->call_depth) {
 974                                         struct merge_file_info mfi;
 975                                         struct diff_filespec one, a, b;
 976
 977                                         one.path = a.path = b.path =
 978                                                 (char *)ren1_dst;
 979                                         hashcpy(one.sha1, null_sha1);
 980                                         one.mode = 0;
 981                                         hashcpy(a.sha1, ren1->pair->two->sha1);
 982                                         a.mode = ren1->pair->two->mode;
 983                                         hashcpy(b.sha1, dst_other.sha1);
 984                                         b.mode = dst_other.mode;
 985                                         mfi = merge_file(o, &one, &a, &b,
 986                                                          branch1,
 987                                                          branch2);
 988                                         output(o, 1, "Adding merged %s", ren1_dst);
 989                                         update_file(o, 0,
 990                                                     mfi.sha,
 991                                                     mfi.mode,
 992                                                     ren1_dst);
 993                                 } else {
 994                                         new_path = unique_path(o, ren1_dst, branch2);
 995                                         output(o, 1, "Adding as %s instead", new_path);
 996                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 997                                 }
 998                         } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
 999                                 ren2 = item->util;
1000                                 clean_merge = 0;
1001                                 ren2->processed = 1;
1002                                 output(o, 1, "CONFLICT (rename/rename): "
1003                                        "Rename %s->%s in %s. "
1004                                        "Rename %s->%s in %s",
1005                                        ren1_src, ren1_dst, branch1,
1006                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
1007                                 conflict_rename_rename_2to1(o, ren1, branch1, ren2, branch2);
1008                         } else
1009                                 try_merge = 1;
1010
1011                         if (try_merge) {
1012                                 struct diff_filespec *one, *a, *b;
1013                                 struct merge_file_info mfi;
1014                                 src_other.path = (char *)ren1_src;
1015
1016                                 one = ren1->pair->one;
1017                                 if (a_renames == renames1) {
1018                                         a = ren1->pair->two;
1019                                         b = &src_other;
1020                                 } else {
1021                                         b = ren1->pair->two;
1022                                         a = &src_other;
1023                                 }
1024                                 mfi = merge_file(o, one, a, b,
1025                                                 o->branch1, o->branch2);
1026
1027                                 if (mfi.clean &&
1028                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1029                                     mfi.mode == ren1->pair->two->mode) {
1030                                         /*
1031                                          * This message is part of
1032                                          * t6022 test. If you change
1033                                          * it update the test too.
1034                                          */
1035                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1036
1037                                         /* There may be higher stage entries left
1038                                          * in the index (e.g. due to a D/F
1039                                          * conflict) that need to be resolved.
1040                                          */
1041                                         if (!ren1->dst_entry->stages[2].mode !=
1042                                             !ren1->dst_entry->stages[3].mode)
1043                                                 ren1->dst_entry->processed = 0;
1044                                 } else {
1045                                         if (mfi.merge || !mfi.clean)
1046                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1047                                         if (mfi.merge)
1048                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1049                                         if (!mfi.clean) {
1050                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1051                                                        ren1_dst);
1052                                                 clean_merge = 0;
1053
1054                                                 if (!o->call_depth)
1055                                                         update_stages(ren1_dst,
1056                                                                       one, a, b, 1);
1057                                         }
1058                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1059                                 }
1060                         }
1061                 }
1062         }
1063         string_list_clear(&a_by_dst, 0);
1064         string_list_clear(&b_by_dst, 0);
1065
1066         return clean_merge;
1067 }
1068
1069 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1070 {
1071         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1072 }
1073
1074 static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1075 {
1076         void *buf;
1077         enum object_type type;
1078         unsigned long size;
1079         buf = read_sha1_file(sha1, &type, &size);
1080         if (!buf)
1081                 return error("cannot read object %s", sha1_to_hex(sha1));
1082         if (type != OBJ_BLOB) {
1083                 free(buf);
1084                 return error("object %s is not a blob", sha1_to_hex(sha1));
1085         }
1086         strbuf_attach(dst, buf, size, size + 1);
1087         return 0;
1088 }
1089
1090 static int blob_unchanged(const unsigned char *o_sha,
1091                           const unsigned char *a_sha,
1092                           int renormalize, const char *path)
1093 {
1094         struct strbuf o = STRBUF_INIT;
1095         struct strbuf a = STRBUF_INIT;
1096         int ret = 0; /* assume changed for safety */
1097
1098         if (sha_eq(o_sha, a_sha))
1099                 return 1;
1100         if (!renormalize)
1101                 return 0;
1102
1103         assert(o_sha && a_sha);
1104         if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1105                 goto error_return;
1106         /*
1107          * Note: binary | is used so that both renormalizations are
1108          * performed.  Comparison can be skipped if both files are
1109          * unchanged since their sha1s have already been compared.
1110          */
1111         if (renormalize_buffer(path, o.buf, o.len, &o) |
1112             renormalize_buffer(path, a.buf, o.len, &a))
1113                 ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1114
1115 error_return:
1116         strbuf_release(&o);
1117         strbuf_release(&a);
1118         return ret;
1119 }
1120
1121 static void handle_delete_modify(struct merge_options *o,
1122                                  const char *path,
1123                                  unsigned char *a_sha, int a_mode,
1124                                  unsigned char *b_sha, int b_mode)
1125 {
1126         if (!a_sha) {
1127                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1128                        "and modified in %s. Version %s of %s left in tree.",
1129                        path, o->branch1,
1130                        o->branch2, o->branch2, path);
1131                 update_file(o, 0, b_sha, b_mode, path);
1132         } else {
1133                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1134                        "and modified in %s. Version %s of %s left in tree.",
1135                        path, o->branch2,
1136                        o->branch1, o->branch1, path);
1137                 update_file(o, 0, a_sha, a_mode, path);
1138         }
1139 }
1140
1141 /* Per entry merge function */
1142 static int process_entry(struct merge_options *o,
1143                          const char *path, struct stage_data *entry)
1144 {
1145         /*
1146         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1147         print_index_entry("\tpath: ", entry);
1148         */
1149         int clean_merge = 1;
1150         int normalize = o->renormalize;
1151         unsigned o_mode = entry->stages[1].mode;
1152         unsigned a_mode = entry->stages[2].mode;
1153         unsigned b_mode = entry->stages[3].mode;
1154         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1155         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1156         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1157
1158         entry->processed = 1;
1159         if (o_sha && (!a_sha || !b_sha)) {
1160                 /* Case A: Deleted in one */
1161                 if ((!a_sha && !b_sha) ||
1162                     (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1163                     (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1164                         /* Deleted in both or deleted in one and
1165                          * unchanged in the other */
1166                         if (a_sha)
1167                                 output(o, 2, "Removing %s", path);
1168                         /* do not touch working file if it did not exist */
1169                         remove_file(o, 1, path, !a_sha);
1170                 } else {
1171                         /* Deleted in one and changed in the other */
1172                         clean_merge = 0;
1173                         handle_delete_modify(o, path,
1174                                              a_sha, a_mode, b_sha, b_mode);
1175                 }
1176
1177         } else if ((!o_sha && a_sha && !b_sha) ||
1178                    (!o_sha && !a_sha && b_sha)) {
1179                 /* Case B: Added in one. */
1180                 unsigned mode;
1181                 const unsigned char *sha;
1182
1183                 if (a_sha) {
1184                         mode = a_mode;
1185                         sha = a_sha;
1186                 } else {
1187                         mode = b_mode;
1188                         sha = b_sha;
1189                 }
1190                 if (string_list_has_string(&o->current_directory_set, path)) {
1191                         /* Handle D->F conflicts after all subfiles */
1192                         entry->processed = 0;
1193                         /* But get any file out of the way now, so conflicted
1194                          * entries below the directory of the same name can
1195                          * be put in the working directory.
1196                          */
1197                         if (a_sha)
1198                                 output(o, 2, "Removing %s", path);
1199                         /* do not touch working file if it did not exist */
1200                         remove_file(o, 0, path, !a_sha);
1201                         return 1; /* Assume clean till processed */
1202                 } else {
1203                         output(o, 2, "Adding %s", path);
1204                         update_file(o, 1, sha, mode, path);
1205                 }
1206         } else if (a_sha && b_sha) {
1207                 /* Case C: Added in both (check for same permissions) and */
1208                 /* case D: Modified in both, but differently. */
1209                 const char *reason = "content";
1210                 struct merge_file_info mfi;
1211                 struct diff_filespec one, a, b;
1212
1213                 if (!o_sha) {
1214                         reason = "add/add";
1215                         o_sha = (unsigned char *)null_sha1;
1216                 }
1217                 output(o, 2, "Auto-merging %s", path);
1218                 one.path = a.path = b.path = (char *)path;
1219                 hashcpy(one.sha1, o_sha);
1220                 one.mode = o_mode;
1221                 hashcpy(a.sha1, a_sha);
1222                 a.mode = a_mode;
1223                 hashcpy(b.sha1, b_sha);
1224                 b.mode = b_mode;
1225
1226                 mfi = merge_file(o, &one, &a, &b,
1227                                  o->branch1, o->branch2);
1228
1229                 clean_merge = mfi.clean;
1230                 if (!mfi.clean) {
1231                         if (S_ISGITLINK(mfi.mode))
1232                                 reason = "submodule";
1233                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1234                                         reason, path);
1235                 }
1236                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1237         } else if (!o_sha && !a_sha && !b_sha) {
1238                 /*
1239                  * this entry was deleted altogether. a_mode == 0 means
1240                  * we had that path and want to actively remove it.
1241                  */
1242                 remove_file(o, 1, path, !a_mode);
1243         } else
1244                 die("Fatal merge failure, shouldn't happen.");
1245
1246         return clean_merge;
1247 }
1248
1249 /*
1250  * Per entry merge function for D/F conflicts, to be called only after
1251  * all files below dir have been processed.  We do this because in the
1252  * cases we can cleanly resolve D/F conflicts, process_entry() can clean
1253  * out all the files below the directory for us.
1254  */
1255 static int process_df_entry(struct merge_options *o,
1256                          const char *path, struct stage_data *entry)
1257 {
1258         int clean_merge = 1;
1259         unsigned o_mode = entry->stages[1].mode;
1260         unsigned a_mode = entry->stages[2].mode;
1261         unsigned b_mode = entry->stages[3].mode;
1262         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1263         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1264         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1265         const char *add_branch;
1266         const char *other_branch;
1267         unsigned mode;
1268         const unsigned char *sha;
1269         const char *conf;
1270         struct stat st;
1271
1272         if (!((!o_sha && a_sha && !b_sha) || (!o_sha && !a_sha && b_sha)))
1273                 return 1; /* we don't handle non D-F cases */
1274
1275         entry->processed = 1;
1276
1277         if (a_sha) {
1278                 add_branch = o->branch1;
1279                 other_branch = o->branch2;
1280                 mode = a_mode;
1281                 sha = a_sha;
1282                 conf = "file/directory";
1283         } else {
1284                 add_branch = o->branch2;
1285                 other_branch = o->branch1;
1286                 mode = b_mode;
1287                 sha = b_sha;
1288                 conf = "directory/file";
1289         }
1290         if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1291                 const char *new_path = unique_path(o, path, add_branch);
1292                 clean_merge = 0;
1293                 output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1294                        "Adding %s as %s",
1295                        conf, path, other_branch, path, new_path);
1296                 remove_file(o, 0, path, 0);
1297                 update_file(o, 0, sha, mode, new_path);
1298         } else {
1299                 output(o, 2, "Adding %s", path);
1300                 update_file(o, 1, sha, mode, path);
1301         }
1302
1303         return clean_merge;
1304 }
1305
1306 int merge_trees(struct merge_options *o,
1307                 struct tree *head,
1308                 struct tree *merge,
1309                 struct tree *common,
1310                 struct tree **result)
1311 {
1312         int code, clean;
1313
1314         if (o->subtree_shift) {
1315                 merge = shift_tree_object(head, merge, o->subtree_shift);
1316                 common = shift_tree_object(head, common, o->subtree_shift);
1317         }
1318
1319         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1320                 output(o, 0, "Already up-to-date!");
1321                 *result = head;
1322                 return 1;
1323         }
1324
1325         code = git_merge_trees(o->call_depth, common, head, merge);
1326
1327         if (code != 0) {
1328                 if (show(o, 4) || o->call_depth)
1329                         die("merging of trees %s and %s failed",
1330                             sha1_to_hex(head->object.sha1),
1331                             sha1_to_hex(merge->object.sha1));
1332                 else
1333                         exit(128);
1334         }
1335
1336         if (unmerged_cache()) {
1337                 struct string_list *entries, *re_head, *re_merge;
1338                 int i;
1339                 string_list_clear(&o->current_file_set, 1);
1340                 string_list_clear(&o->current_directory_set, 1);
1341                 get_files_dirs(o, head);
1342                 get_files_dirs(o, merge);
1343
1344                 entries = get_unmerged();
1345                 re_head  = get_renames(o, head, common, head, merge, entries);
1346                 re_merge = get_renames(o, merge, common, head, merge, entries);
1347                 clean = process_renames(o, re_head, re_merge);
1348                 for (i = 0; i < entries->nr; i++) {
1349                         const char *path = entries->items[i].string;
1350                         struct stage_data *e = entries->items[i].util;
1351                         if (!e->processed
1352                                 && !process_entry(o, path, e))
1353                                 clean = 0;
1354                 }
1355                 for (i = 0; i < entries->nr; i++) {
1356                         const char *path = entries->items[i].string;
1357                         struct stage_data *e = entries->items[i].util;
1358                         if (!e->processed
1359                                 && !process_df_entry(o, path, e))
1360                                 clean = 0;
1361                 }
1362                 for (i = 0; i < entries->nr; i++) {
1363                         struct stage_data *e = entries->items[i].util;
1364                         if (!e->processed)
1365                                 die("Unprocessed path??? %s",
1366                                     entries->items[i].string);
1367                 }
1368
1369                 string_list_clear(re_merge, 0);
1370                 string_list_clear(re_head, 0);
1371                 string_list_clear(entries, 1);
1372
1373         }
1374         else
1375                 clean = 1;
1376
1377         if (o->call_depth)
1378                 *result = write_tree_from_memory(o);
1379
1380         return clean;
1381 }
1382
1383 static struct commit_list *reverse_commit_list(struct commit_list *list)
1384 {
1385         struct commit_list *next = NULL, *current, *backup;
1386         for (current = list; current; current = backup) {
1387                 backup = current->next;
1388                 current->next = next;
1389                 next = current;
1390         }
1391         return next;
1392 }
1393
1394 /*
1395  * Merge the commits h1 and h2, return the resulting virtual
1396  * commit object and a flag indicating the cleanness of the merge.
1397  */
1398 int merge_recursive(struct merge_options *o,
1399                     struct commit *h1,
1400                     struct commit *h2,
1401                     struct commit_list *ca,
1402                     struct commit **result)
1403 {
1404         struct commit_list *iter;
1405         struct commit *merged_common_ancestors;
1406         struct tree *mrtree = mrtree;
1407         int clean;
1408
1409         if (show(o, 4)) {
1410                 output(o, 4, "Merging:");
1411                 output_commit_title(o, h1);
1412                 output_commit_title(o, h2);
1413         }
1414
1415         if (!ca) {
1416                 ca = get_merge_bases(h1, h2, 1);
1417                 ca = reverse_commit_list(ca);
1418         }
1419
1420         if (show(o, 5)) {
1421                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1422                 for (iter = ca; iter; iter = iter->next)
1423                         output_commit_title(o, iter->item);
1424         }
1425
1426         merged_common_ancestors = pop_commit(&ca);
1427         if (merged_common_ancestors == NULL) {
1428                 /* if there is no common ancestor, make an empty tree */
1429                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1430
1431                 tree->object.parsed = 1;
1432                 tree->object.type = OBJ_TREE;
1433                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1434                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1435         }
1436
1437         for (iter = ca; iter; iter = iter->next) {
1438                 const char *saved_b1, *saved_b2;
1439                 o->call_depth++;
1440                 /*
1441                  * When the merge fails, the result contains files
1442                  * with conflict markers. The cleanness flag is
1443                  * ignored, it was never actually used, as result of
1444                  * merge_trees has always overwritten it: the committed
1445                  * "conflicts" were already resolved.
1446                  */
1447                 discard_cache();
1448                 saved_b1 = o->branch1;
1449                 saved_b2 = o->branch2;
1450                 o->branch1 = "Temporary merge branch 1";
1451                 o->branch2 = "Temporary merge branch 2";
1452                 merge_recursive(o, merged_common_ancestors, iter->item,
1453                                 NULL, &merged_common_ancestors);
1454                 o->branch1 = saved_b1;
1455                 o->branch2 = saved_b2;
1456                 o->call_depth--;
1457
1458                 if (!merged_common_ancestors)
1459                         die("merge returned no commit");
1460         }
1461
1462         discard_cache();
1463         if (!o->call_depth)
1464                 read_cache();
1465
1466         o->ancestor = "merged common ancestors";
1467         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1468                             &mrtree);
1469
1470         if (o->call_depth) {
1471                 *result = make_virtual_commit(mrtree, "merged tree");
1472                 commit_list_insert(h1, &(*result)->parents);
1473                 commit_list_insert(h2, &(*result)->parents->next);
1474         }
1475         flush_output(o);
1476         return clean;
1477 }
1478
1479 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1480 {
1481         struct object *object;
1482
1483         object = deref_tag(parse_object(sha1), name, strlen(name));
1484         if (!object)
1485                 return NULL;
1486         if (object->type == OBJ_TREE)
1487                 return make_virtual_commit((struct tree*)object, name);
1488         if (object->type != OBJ_COMMIT)
1489                 return NULL;
1490         if (parse_commit((struct commit *)object))
1491                 return NULL;
1492         return (struct commit *)object;
1493 }
1494
1495 int merge_recursive_generic(struct merge_options *o,
1496                             const unsigned char *head,
1497                             const unsigned char *merge,
1498                             int num_base_list,
1499                             const unsigned char **base_list,
1500                             struct commit **result)
1501 {
1502         int clean, index_fd;
1503         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1504         struct commit *head_commit = get_ref(head, o->branch1);
1505         struct commit *next_commit = get_ref(merge, o->branch2);
1506         struct commit_list *ca = NULL;
1507
1508         if (base_list) {
1509                 int i;
1510                 for (i = 0; i < num_base_list; ++i) {
1511                         struct commit *base;
1512                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1513                                 return error("Could not parse object '%s'",
1514                                         sha1_to_hex(base_list[i]));
1515                         commit_list_insert(base, &ca);
1516                 }
1517         }
1518
1519         index_fd = hold_locked_index(lock, 1);
1520         clean = merge_recursive(o, head_commit, next_commit, ca,
1521                         result);
1522         if (active_cache_changed &&
1523                         (write_cache(index_fd, active_cache, active_nr) ||
1524                          commit_locked_index(lock)))
1525                 return error("Unable to write index.");
1526
1527         return clean ? 0 : 1;
1528 }
1529
1530 static int merge_recursive_config(const char *var, const char *value, void *cb)
1531 {
1532         struct merge_options *o = cb;
1533         if (!strcasecmp(var, "merge.verbosity")) {
1534                 o->verbosity = git_config_int(var, value);
1535                 return 0;
1536         }
1537         if (!strcasecmp(var, "diff.renamelimit")) {
1538                 o->diff_rename_limit = git_config_int(var, value);
1539                 return 0;
1540         }
1541         if (!strcasecmp(var, "merge.renamelimit")) {
1542                 o->merge_rename_limit = git_config_int(var, value);
1543                 return 0;
1544         }
1545         return git_xmerge_config(var, value, cb);
1546 }
1547
1548 void init_merge_options(struct merge_options *o)
1549 {
1550         memset(o, 0, sizeof(struct merge_options));
1551         o->verbosity = 2;
1552         o->buffer_output = 1;
1553         o->diff_rename_limit = -1;
1554         o->merge_rename_limit = -1;
1555         o->renormalize = 0;
1556         git_config(merge_recursive_config, o);
1557         if (getenv("GIT_MERGE_VERBOSITY"))
1558                 o->verbosity =
1559                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1560         if (o->verbosity >= 5)
1561                 o->buffer_output = 0;
1562         strbuf_init(&o->obuf, 0);
1563         memset(&o->current_file_set, 0, sizeof(struct string_list));
1564         o->current_file_set.strdup_strings = 1;
1565         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1566         o->current_directory_set.strdup_strings = 1;
1567 }