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
  24 static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  25 {
  26         unsigned char shifted[20];
  27
  28         /*
  29          * NEEDSWORK: this limits the recursion depth to hardcoded
  30          * value '2' to avoid excessive overhead.
  31          */
  32         shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  33         if (!hashcmp(two->object.sha1, shifted))
  34                 return two;
  35         return lookup_tree(shifted);
  36 }
  37
  38 /*
  39  * A virtual commit has (const char *)commit->util set to the name.
  40  */
  41
  42 static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  43 {
  44         struct commit *commit = xcalloc(1, sizeof(struct commit));
  45         commit->tree = tree;
  46         commit->util = (void*)comment;
  47         /* avoid warnings */
  48         commit->object.parsed = 1;
  49         return commit;
  50 }
  51
  52 /*
  53  * Since we use get_tree_entry(), which does not put the read object into
  54  * the object pool, we cannot rely on a == b.
  55  */
  56 static int sha_eq(const unsigned char *a, const unsigned char *b)
  57 {
  58         if (!a && !b)
  59                 return 2;
  60         return a && b && hashcmp(a, b) == 0;
  61 }
  62
  63 /*
  64  * Since we want to write the index eventually, we cannot reuse the index
  65  * for these (temporary) data.
  66  */
  67 struct stage_data
  68 {
  69         struct
  70         {
  71                 unsigned mode;
  72                 unsigned char sha[20];
  73         } stages[4];
  74         unsigned processed:1;
  75 };
  76
  77 static int show(struct merge_options *o, int v)
  78 {
  79         return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  80 }
  81
  82 static void flush_output(struct merge_options *o)
  83 {
  84         if (o->obuf.len) {
  85                 fputs(o->obuf.buf, stdout);
  86                 strbuf_reset(&o->obuf);
  87         }
  88 }
  89
  90 __attribute__((format (printf, 3, 4)))
  91 static void output(struct merge_options *o, int v, const char *fmt, ...)
  92 {
  93         int len;
  94         va_list ap;
  95
  96         if (!show(o, v))
  97                 return;
  98
  99         strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 100         memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 101         strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 102
 103         va_start(ap, fmt);
 104         len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 105         va_end(ap);
 106
 107         if (len < 0)
 108                 len = 0;
 109         if (len >= strbuf_avail(&o->obuf)) {
 110                 strbuf_grow(&o->obuf, len + 2);
 111                 va_start(ap, fmt);
 112                 len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 113                 va_end(ap);
 114                 if (len >= strbuf_avail(&o->obuf)) {
 115                         die("this should not happen, your snprintf is broken");
 116                 }
 117         }
 118         strbuf_setlen(&o->obuf, o->obuf.len + len);
 119         strbuf_add(&o->obuf, "\n", 1);
 120         if (!o->buffer_output)
 121                 flush_output(o);
 122 }
 123
 124 static void output_commit_title(struct merge_options *o, struct commit *commit)
 125 {
 126         int i;
 127         flush_output(o);
 128         for (i = o->call_depth; i--;)
 129                 fputs("  ", stdout);
 130         if (commit->util)
 131                 printf("virtual %s\n", (char *)commit->util);
 132         else {
 133                 printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 134                 if (parse_commit(commit) != 0)
 135                         printf("(bad commit)\n");
 136                 else {
 137                         const char *s;
 138                         int len;
 139                         for (s = commit->buffer; *s; s++)
 140                                 if (*s == '\n' && s[1] == '\n') {
 141                                         s += 2;
 142                                         break;
 143                                 }
 144                         for (len = 0; s[len] && '\n' != s[len]; len++)
 145                                 ; /* do nothing */
 146                         printf("%.*s\n", len, s);
 147                 }
 148         }
 149 }
 150
 151 static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 152                 const char *path, int stage, int refresh, int options)
 153 {
 154         struct cache_entry *ce;
 155         ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 156         if (!ce)
 157                 return error("addinfo_cache failed for path '%s'", path);
 158         return add_cache_entry(ce, options);
 159 }
 160
 161 static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 162 {
 163         parse_tree(tree);
 164         init_tree_desc(desc, tree->buffer, tree->size);
 165 }
 166
 167 static int git_merge_trees(int index_only,
 168                            struct tree *common,
 169                            struct tree *head,
 170                            struct tree *merge)
 171 {
 172         int rc;
 173         struct tree_desc t[3];
 174         struct unpack_trees_options opts;
 175
 176         memset(&opts, 0, sizeof(opts));
 177         if (index_only)
 178                 opts.index_only = 1;
 179         else
 180                 opts.update = 1;
 181         opts.merge = 1;
 182         opts.head_idx = 2;
 183         opts.fn = threeway_merge;
 184         opts.src_index = &the_index;
 185         opts.dst_index = &the_index;
 186         opts.msgs = get_porcelain_error_msgs();
 187
 188         init_tree_desc_from_tree(t+0, common);
 189         init_tree_desc_from_tree(t+1, head);
 190         init_tree_desc_from_tree(t+2, merge);
 191
 192         rc = unpack_trees(3, t, &opts);
 193         cache_tree_free(&active_cache_tree);
 194         return rc;
 195 }
 196
 197 struct tree *write_tree_from_memory(struct merge_options *o)
 198 {
 199         struct tree *result = NULL;
 200
 201         if (unmerged_cache()) {
 202                 int i;
 203                 output(o, 0, "There are unmerged index entries:");
 204                 for (i = 0; i < active_nr; i++) {
 205                         struct cache_entry *ce = active_cache[i];
 206                         if (ce_stage(ce))
 207                                 output(o, 0, "%d %.*s", ce_stage(ce),
 208                                        (int)ce_namelen(ce), ce->name);
 209                 }
 210                 return NULL;
 211         }
 212
 213         if (!active_cache_tree)
 214                 active_cache_tree = cache_tree();
 215
 216         if (!cache_tree_fully_valid(active_cache_tree) &&
 217             cache_tree_update(active_cache_tree,
 218                               active_cache, active_nr, 0, 0) < 0)
 219                 die("error building trees");
 220
 221         result = lookup_tree(active_cache_tree->sha1);
 222
 223         return result;
 224 }
 225
 226 static int save_files_dirs(const unsigned char *sha1,
 227                 const char *base, int baselen, const char *path,
 228                 unsigned int mode, int stage, void *context)
 229 {
 230         int len = strlen(path);
 231         char *newpath = xmalloc(baselen + len + 1);
 232         struct merge_options *o = context;
 233
 234         memcpy(newpath, base, baselen);
 235         memcpy(newpath + baselen, path, len);
 236         newpath[baselen + len] = '\0';
 237
 238         if (S_ISDIR(mode))
 239                 string_list_insert(newpath, &o->current_directory_set);
 240         else
 241                 string_list_insert(newpath, &o->current_file_set);
 242         free(newpath);
 243
 244         return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 245 }
 246
 247 static int get_files_dirs(struct merge_options *o, struct tree *tree)
 248 {
 249         int n;
 250         if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 251                 return 0;
 252         n = o->current_file_set.nr + o->current_directory_set.nr;
 253         return n;
 254 }
 255
 256 /*
 257  * Returns an index_entry instance which doesn't have to correspond to
 258  * a real cache entry in Git's index.
 259  */
 260 static struct stage_data *insert_stage_data(const char *path,
 261                 struct tree *o, struct tree *a, struct tree *b,
 262                 struct string_list *entries)
 263 {
 264         struct string_list_item *item;
 265         struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 266         get_tree_entry(o->object.sha1, path,
 267                         e->stages[1].sha, &e->stages[1].mode);
 268         get_tree_entry(a->object.sha1, path,
 269                         e->stages[2].sha, &e->stages[2].mode);
 270         get_tree_entry(b->object.sha1, path,
 271                         e->stages[3].sha, &e->stages[3].mode);
 272         item = string_list_insert(path, entries);
 273         item->util = e;
 274         return e;
 275 }
 276
 277 /*
 278  * Create a dictionary mapping file names to stage_data objects. The
 279  * dictionary contains one entry for every path with a non-zero stage entry.
 280  */
 281 static struct string_list *get_unmerged(void)
 282 {
 283         struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 284         int i;
 285
 286         unmerged->strdup_strings = 1;
 287
 288         for (i = 0; i < active_nr; i++) {
 289                 struct string_list_item *item;
 290                 struct stage_data *e;
 291                 struct cache_entry *ce = active_cache[i];
 292                 if (!ce_stage(ce))
 293                         continue;
 294
 295                 item = string_list_lookup(ce->name, unmerged);
 296                 if (!item) {
 297                         item = string_list_insert(ce->name, unmerged);
 298                         item->util = xcalloc(1, sizeof(struct stage_data));
 299                 }
 300                 e = item->util;
 301                 e->stages[ce_stage(ce)].mode = ce->ce_mode;
 302                 hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 303         }
 304
 305         return unmerged;
 306 }
 307
 308 struct rename
 309 {
 310         struct diff_filepair *pair;
 311         struct stage_data *src_entry;
 312         struct stage_data *dst_entry;
 313         unsigned processed:1;
 314 };
 315
 316 /*
 317  * Get information of all renames which occurred between 'o_tree' and
 318  * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 319  * 'b_tree') to be able to associate the correct cache entries with
 320  * the rename information. 'tree' is always equal to either a_tree or b_tree.
 321  */
 322 static struct string_list *get_renames(struct merge_options *o,
 323                                        struct tree *tree,
 324                                        struct tree *o_tree,
 325                                        struct tree *a_tree,
 326                                        struct tree *b_tree,
 327                                        struct string_list *entries)
 328 {
 329         int i;
 330         struct string_list *renames;
 331         struct diff_options opts;
 332
 333         renames = xcalloc(1, sizeof(struct string_list));
 334         diff_setup(&opts);
 335         DIFF_OPT_SET(&opts, RECURSIVE);
 336         opts.detect_rename = DIFF_DETECT_RENAME;
 337         opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 338                             o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 339                             500;
 340         opts.warn_on_too_large_rename = 1;
 341         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 342         if (diff_setup_done(&opts) < 0)
 343                 die("diff setup failed");
 344         diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 345         diffcore_std(&opts);
 346         for (i = 0; i < diff_queued_diff.nr; ++i) {
 347                 struct string_list_item *item;
 348                 struct rename *re;
 349                 struct diff_filepair *pair = diff_queued_diff.queue[i];
 350                 if (pair->status != 'R') {
 351                         diff_free_filepair(pair);
 352                         continue;
 353                 }
 354                 re = xmalloc(sizeof(*re));
 355                 re->processed = 0;
 356                 re->pair = pair;
 357                 item = string_list_lookup(re->pair->one->path, entries);
 358                 if (!item)
 359                         re->src_entry = insert_stage_data(re->pair->one->path,
 360                                         o_tree, a_tree, b_tree, entries);
 361                 else
 362                         re->src_entry = item->util;
 363
 364                 item = string_list_lookup(re->pair->two->path, entries);
 365                 if (!item)
 366                         re->dst_entry = insert_stage_data(re->pair->two->path,
 367                                         o_tree, a_tree, b_tree, entries);
 368                 else
 369                         re->dst_entry = item->util;
 370                 item = string_list_insert(pair->one->path, renames);
 371                 item->util = re;
 372         }
 373         opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 374         diff_queued_diff.nr = 0;
 375         diff_flush(&opts);
 376         return renames;
 377 }
 378
 379 static int update_stages(const char *path, struct diff_filespec *o,
 380                          struct diff_filespec *a, struct diff_filespec *b,
 381                          int clear)
 382 {
 383         int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 384         if (clear)
 385                 if (remove_file_from_cache(path))
 386                         return -1;
 387         if (o)
 388                 if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 389                         return -1;
 390         if (a)
 391                 if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 392                         return -1;
 393         if (b)
 394                 if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 395                         return -1;
 396         return 0;
 397 }
 398
 399 static int remove_file(struct merge_options *o, int clean,
 400                        const char *path, int no_wd)
 401 {
 402         int update_cache = o->call_depth || clean;
 403         int update_working_directory = !o->call_depth && !no_wd;
 404
 405         if (update_cache) {
 406                 if (remove_file_from_cache(path))
 407                         return -1;
 408         }
 409         if (update_working_directory) {
 410                 if (remove_path(path) && errno != ENOENT)
 411                         return -1;
 412         }
 413         return 0;
 414 }
 415
 416 static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 417 {
 418         char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 419         int suffix = 0;
 420         struct stat st;
 421         char *p = newpath + strlen(path);
 422         strcpy(newpath, path);
 423         *(p++) = '~';
 424         strcpy(p, branch);
 425         for (; *p; ++p)
 426                 if ('/' == *p)
 427                         *p = '_';
 428         while (string_list_has_string(&o->current_file_set, newpath) ||
 429                string_list_has_string(&o->current_directory_set, newpath) ||
 430                lstat(newpath, &st) == 0)
 431                 sprintf(p, "_%d", suffix++);
 432
 433         string_list_insert(newpath, &o->current_file_set);
 434         return newpath;
 435 }
 436
 437 static void flush_buffer(int fd, const char *buf, unsigned long size)
 438 {
 439         while (size > 0) {
 440                 long ret = write_in_full(fd, buf, size);
 441                 if (ret < 0) {
 442                         /* Ignore epipe */
 443                         if (errno == EPIPE)
 444                                 break;
 445                         die_errno("merge-recursive");
 446                 } else if (!ret) {
 447                         die("merge-recursive: disk full?");
 448                 }
 449                 size -= ret;
 450                 buf += ret;
 451         }
 452 }
 453
 454 static int would_lose_untracked(const char *path)
 455 {
 456         int pos = cache_name_pos(path, strlen(path));
 457
 458         if (pos < 0)
 459                 pos = -1 - pos;
 460         while (pos < active_nr &&
 461                !strcmp(path, active_cache[pos]->name)) {
 462                 /*
 463                  * If stage #0, it is definitely tracked.
 464                  * If it has stage #2 then it was tracked
 465                  * before this merge started.  All other
 466                  * cases the path was not tracked.
 467                  */
 468                 switch (ce_stage(active_cache[pos])) {
 469                 case 0:
 470                 case 2:
 471                         return 0;
 472                 }
 473                 pos++;
 474         }
 475         return file_exists(path);
 476 }
 477
 478 static int make_room_for_path(const char *path)
 479 {
 480         int status;
 481         const char *msg = "failed to create path '%s'%s";
 482
 483         status = safe_create_leading_directories_const(path);
 484         if (status) {
 485                 if (status == -3) {
 486                         /* something else exists */
 487                         error(msg, path, ": perhaps a D/F conflict?");
 488                         return -1;
 489                 }
 490                 die(msg, path, "");
 491         }
 492
 493         /*
 494          * Do not unlink a file in the work tree if we are not
 495          * tracking it.
 496          */
 497         if (would_lose_untracked(path))
 498                 return error("refusing to lose untracked file at '%s'",
 499                              path);
 500
 501         /* Successful unlink is good.. */
 502         if (!unlink(path))
 503                 return 0;
 504         /* .. and so is no existing file */
 505         if (errno == ENOENT)
 506                 return 0;
 507         /* .. but not some other error (who really cares what?) */
 508         return error(msg, path, ": perhaps a D/F conflict?");
 509 }
 510
 511 static void update_file_flags(struct merge_options *o,
 512                               const unsigned char *sha,
 513                               unsigned mode,
 514                               const char *path,
 515                               int update_cache,
 516                               int update_wd)
 517 {
 518         if (o->call_depth)
 519                 update_wd = 0;
 520
 521         if (update_wd) {
 522                 enum object_type type;
 523                 void *buf;
 524                 unsigned long size;
 525
 526                 if (S_ISGITLINK(mode))
 527                         /*
 528                          * We may later decide to recursively descend into
 529                          * the submodule directory and update its index
 530                          * and/or work tree, but we do not do that now.
 531                          */
 532                         goto update_index;
 533
 534                 buf = read_sha1_file(sha, &type, &size);
 535                 if (!buf)
 536                         die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 537                 if (type != OBJ_BLOB)
 538                         die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 539                 if (S_ISREG(mode)) {
 540                         struct strbuf strbuf = STRBUF_INIT;
 541                         if (convert_to_working_tree(path, buf, size, &strbuf)) {
 542                                 free(buf);
 543                                 size = strbuf.len;
 544                                 buf = strbuf_detach(&strbuf, NULL);
 545                         }
 546                 }
 547
 548                 if (make_room_for_path(path) < 0) {
 549                         update_wd = 0;
 550                         free(buf);
 551                         goto update_index;
 552                 }
 553                 if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 554                         int fd;
 555                         if (mode & 0100)
 556                                 mode = 0777;
 557                         else
 558                                 mode = 0666;
 559                         fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 560                         if (fd < 0)
 561                                 die_errno("failed to open '%s'", path);
 562                         flush_buffer(fd, buf, size);
 563                         close(fd);
 564                 } else if (S_ISLNK(mode)) {
 565                         char *lnk = xmemdupz(buf, size);
 566                         safe_create_leading_directories_const(path);
 567                         unlink(path);
 568                         if (symlink(lnk, path))
 569                                 die_errno("failed to symlink '%s'", path);
 570                         free(lnk);
 571                 } else
 572                         die("do not know what to do with %06o %s '%s'",
 573                             mode, sha1_to_hex(sha), path);
 574                 free(buf);
 575         }
 576  update_index:
 577         if (update_cache)
 578                 add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 579 }
 580
 581 static void update_file(struct merge_options *o,
 582                         int clean,
 583                         const unsigned char *sha,
 584                         unsigned mode,
 585                         const char *path)
 586 {
 587         update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 588 }
 589
 590 /* Low level file merging, update and removal */
 591
 592 struct merge_file_info
 593 {
 594         unsigned char sha[20];
 595         unsigned mode;
 596         unsigned clean:1,
 597                  merge:1;
 598 };
 599
 600 static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 601 {
 602         unsigned long size;
 603         enum object_type type;
 604
 605         if (!hashcmp(sha1, null_sha1)) {
 606                 mm->ptr = xstrdup("");
 607                 mm->size = 0;
 608                 return;
 609         }
 610
 611         mm->ptr = read_sha1_file(sha1, &type, &size);
 612         if (!mm->ptr || type != OBJ_BLOB)
 613                 die("unable to read blob object %s", sha1_to_hex(sha1));
 614         mm->size = size;
 615 }
 616
 617 static int merge_3way(struct merge_options *o,
 618                       mmbuffer_t *result_buf,
 619                       struct diff_filespec *one,
 620                       struct diff_filespec *a,
 621                       struct diff_filespec *b,
 622                       const char *branch1,
 623                       const char *branch2)
 624 {
 625         mmfile_t orig, src1, src2;
 626         char *name1, *name2;
 627         int merge_status;
 628
 629         if (strcmp(a->path, b->path)) {
 630                 name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 631                 name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 632         } else {
 633                 name1 = xstrdup(mkpath("%s", branch1));
 634                 name2 = xstrdup(mkpath("%s", branch2));
 635         }
 636
 637         fill_mm(one->sha1, &orig);
 638         fill_mm(a->sha1, &src1);
 639         fill_mm(b->sha1, &src2);
 640
 641         merge_status = ll_merge(result_buf, a->path, &orig,
 642                                 &src1, name1, &src2, name2,
 643                                 o->call_depth);
 644
 645         free(name1);
 646         free(name2);
 647         free(orig.ptr);
 648         free(src1.ptr);
 649         free(src2.ptr);
 650         return merge_status;
 651 }
 652
 653 static struct merge_file_info merge_file(struct merge_options *o,
 654                                          struct diff_filespec *one,
 655                                          struct diff_filespec *a,
 656                                          struct diff_filespec *b,
 657                                          const char *branch1,
 658                                          const char *branch2)
 659 {
 660         struct merge_file_info result;
 661         result.merge = 0;
 662         result.clean = 1;
 663
 664         if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 665                 result.clean = 0;
 666                 if (S_ISREG(a->mode)) {
 667                         result.mode = a->mode;
 668                         hashcpy(result.sha, a->sha1);
 669                 } else {
 670                         result.mode = b->mode;
 671                         hashcpy(result.sha, b->sha1);
 672                 }
 673         } else {
 674                 if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 675                         result.merge = 1;
 676
 677                 /*
 678                  * Merge modes
 679                  */
 680                 if (a->mode == b->mode || a->mode == one->mode)
 681                         result.mode = b->mode;
 682                 else {
 683                         result.mode = a->mode;
 684                         if (b->mode != one->mode) {
 685                                 result.clean = 0;
 686                                 result.merge = 1;
 687                         }
 688                 }
 689
 690                 if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 691                         hashcpy(result.sha, b->sha1);
 692                 else if (sha_eq(b->sha1, one->sha1))
 693                         hashcpy(result.sha, a->sha1);
 694                 else if (S_ISREG(a->mode)) {
 695                         mmbuffer_t result_buf;
 696                         int merge_status;
 697
 698                         merge_status = merge_3way(o, &result_buf, one, a, b,
 699                                                   branch1, branch2);
 700
 701                         if ((merge_status < 0) || !result_buf.ptr)
 702                                 die("Failed to execute internal merge");
 703
 704                         if (write_sha1_file(result_buf.ptr, result_buf.size,
 705                                             blob_type, result.sha))
 706                                 die("Unable to add %s to database",
 707                                     a->path);
 708
 709                         free(result_buf.ptr);
 710                         result.clean = (merge_status == 0);
 711                 } else if (S_ISGITLINK(a->mode)) {
 712                         result.clean = 0;
 713                         hashcpy(result.sha, a->sha1);
 714                 } else if (S_ISLNK(a->mode)) {
 715                         hashcpy(result.sha, a->sha1);
 716
 717                         if (!sha_eq(a->sha1, b->sha1))
 718                                 result.clean = 0;
 719                 } else {
 720                         die("unsupported object type in the tree");
 721                 }
 722         }
 723
 724         return result;
 725 }
 726
 727 static void conflict_rename_rename(struct merge_options *o,
 728                                    struct rename *ren1,
 729                                    const char *branch1,
 730                                    struct rename *ren2,
 731                                    const char *branch2)
 732 {
 733         char *del[2];
 734         int delp = 0;
 735         const char *ren1_dst = ren1->pair->two->path;
 736         const char *ren2_dst = ren2->pair->two->path;
 737         const char *dst_name1 = ren1_dst;
 738         const char *dst_name2 = ren2_dst;
 739         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 740                 dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 741                 output(o, 1, "%s is a directory in %s adding as %s instead",
 742                        ren1_dst, branch2, dst_name1);
 743                 remove_file(o, 0, ren1_dst, 0);
 744         }
 745         if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 746                 dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 747                 output(o, 1, "%s is a directory in %s adding as %s instead",
 748                        ren2_dst, branch1, dst_name2);
 749                 remove_file(o, 0, ren2_dst, 0);
 750         }
 751         if (o->call_depth) {
 752                 remove_file_from_cache(dst_name1);
 753                 remove_file_from_cache(dst_name2);
 754                 /*
 755                  * Uncomment to leave the conflicting names in the resulting tree
 756                  *
 757                  * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 758                  * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 759                  */
 760         } else {
 761                 update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 762                 update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 763         }
 764         while (delp--)
 765                 free(del[delp]);
 766 }
 767
 768 static void conflict_rename_dir(struct merge_options *o,
 769                                 struct rename *ren1,
 770                                 const char *branch1)
 771 {
 772         char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 773         output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 774         remove_file(o, 0, ren1->pair->two->path, 0);
 775         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 776         free(new_path);
 777 }
 778
 779 static void conflict_rename_rename_2(struct merge_options *o,
 780                                      struct rename *ren1,
 781                                      const char *branch1,
 782                                      struct rename *ren2,
 783                                      const char *branch2)
 784 {
 785         char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 786         char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 787         output(o, 1, "Renaming %s to %s and %s to %s instead",
 788                ren1->pair->one->path, new_path1,
 789                ren2->pair->one->path, new_path2);
 790         remove_file(o, 0, ren1->pair->two->path, 0);
 791         update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 792         update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 793         free(new_path2);
 794         free(new_path1);
 795 }
 796
 797 static int process_renames(struct merge_options *o,
 798                            struct string_list *a_renames,
 799                            struct string_list *b_renames)
 800 {
 801         int clean_merge = 1, i, j;
 802         struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 803         const struct rename *sre;
 804
 805         for (i = 0; i < a_renames->nr; i++) {
 806                 sre = a_renames->items[i].util;
 807                 string_list_insert(sre->pair->two->path, &a_by_dst)->util
 808                         = sre->dst_entry;
 809         }
 810         for (i = 0; i < b_renames->nr; i++) {
 811                 sre = b_renames->items[i].util;
 812                 string_list_insert(sre->pair->two->path, &b_by_dst)->util
 813                         = sre->dst_entry;
 814         }
 815
 816         for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 817                 char *src;
 818                 struct string_list *renames1, *renames2Dst;
 819                 struct rename *ren1 = NULL, *ren2 = NULL;
 820                 const char *branch1, *branch2;
 821                 const char *ren1_src, *ren1_dst;
 822
 823                 if (i >= a_renames->nr) {
 824                         ren2 = b_renames->items[j++].util;
 825                 } else if (j >= b_renames->nr) {
 826                         ren1 = a_renames->items[i++].util;
 827                 } else {
 828                         int compare = strcmp(a_renames->items[i].string,
 829                                              b_renames->items[j].string);
 830                         if (compare <= 0)
 831                                 ren1 = a_renames->items[i++].util;
 832                         if (compare >= 0)
 833                                 ren2 = b_renames->items[j++].util;
 834                 }
 835
 836                 /* TODO: refactor, so that 1/2 are not needed */
 837                 if (ren1) {
 838                         renames1 = a_renames;
 839                         renames2Dst = &b_by_dst;
 840                         branch1 = o->branch1;
 841                         branch2 = o->branch2;
 842                 } else {
 843                         struct rename *tmp;
 844                         renames1 = b_renames;
 845                         renames2Dst = &a_by_dst;
 846                         branch1 = o->branch2;
 847                         branch2 = o->branch1;
 848                         tmp = ren2;
 849                         ren2 = ren1;
 850                         ren1 = tmp;
 851                 }
 852                 src = ren1->pair->one->path;
 853
 854                 ren1->dst_entry->processed = 1;
 855                 ren1->src_entry->processed = 1;
 856
 857                 if (ren1->processed)
 858                         continue;
 859                 ren1->processed = 1;
 860
 861                 ren1_src = ren1->pair->one->path;
 862                 ren1_dst = ren1->pair->two->path;
 863
 864                 if (ren2) {
 865                         const char *ren2_src = ren2->pair->one->path;
 866                         const char *ren2_dst = ren2->pair->two->path;
 867                         /* Renamed in 1 and renamed in 2 */
 868                         if (strcmp(ren1_src, ren2_src) != 0)
 869                                 die("ren1.src != ren2.src");
 870                         ren2->dst_entry->processed = 1;
 871                         ren2->processed = 1;
 872                         if (strcmp(ren1_dst, ren2_dst) != 0) {
 873                                 clean_merge = 0;
 874                                 output(o, 1, "CONFLICT (rename/rename): "
 875                                        "Rename \"%s\"->\"%s\" in branch \"%s\" "
 876                                        "rename \"%s\"->\"%s\" in \"%s\"%s",
 877                                        src, ren1_dst, branch1,
 878                                        src, ren2_dst, branch2,
 879                                        o->call_depth ? " (left unresolved)": "");
 880                                 if (o->call_depth) {
 881                                         remove_file_from_cache(src);
 882                                         update_file(o, 0, ren1->pair->one->sha1,
 883                                                     ren1->pair->one->mode, src);
 884                                 }
 885                                 conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 886                         } else {
 887                                 struct merge_file_info mfi;
 888                                 remove_file(o, 1, ren1_src, 1);
 889                                 mfi = merge_file(o,
 890                                                  ren1->pair->one,
 891                                                  ren1->pair->two,
 892                                                  ren2->pair->two,
 893                                                  branch1,
 894                                                  branch2);
 895                                 if (mfi.merge || !mfi.clean)
 896                                         output(o, 1, "Renaming %s->%s", src, ren1_dst);
 897
 898                                 if (mfi.merge)
 899                                         output(o, 2, "Auto-merging %s", ren1_dst);
 900
 901                                 if (!mfi.clean) {
 902                                         output(o, 1, "CONFLICT (content): merge conflict in %s",
 903                                                ren1_dst);
 904                                         clean_merge = 0;
 905
 906                                         if (!o->call_depth)
 907                                                 update_stages(ren1_dst,
 908                                                               ren1->pair->one,
 909                                                               ren1->pair->two,
 910                                                               ren2->pair->two,
 911                                                               1 /* clear */);
 912                                 }
 913                                 update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 914                         }
 915                 } else {
 916                         /* Renamed in 1, maybe changed in 2 */
 917                         struct string_list_item *item;
 918                         /* we only use sha1 and mode of these */
 919                         struct diff_filespec src_other, dst_other;
 920                         int try_merge, stage = a_renames == renames1 ? 3: 2;
 921
 922                         remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 923
 924                         hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 925                         src_other.mode = ren1->src_entry->stages[stage].mode;
 926                         hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 927                         dst_other.mode = ren1->dst_entry->stages[stage].mode;
 928
 929                         try_merge = 0;
 930
 931                         if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 932                                 clean_merge = 0;
 933                                 output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 934                                        " directory %s added in %s",
 935                                        ren1_src, ren1_dst, branch1,
 936                                        ren1_dst, branch2);
 937                                 conflict_rename_dir(o, ren1, branch1);
 938                         } else if (sha_eq(src_other.sha1, null_sha1)) {
 939                                 clean_merge = 0;
 940                                 output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 941                                        "and deleted in %s",
 942                                        ren1_src, ren1_dst, branch1,
 943                                        branch2);
 944                                 update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 945                                 if (!o->call_depth)
 946                                         update_stages(ren1_dst, NULL,
 947                                                         branch1 == o->branch1 ?
 948                                                         ren1->pair->two : NULL,
 949                                                         branch1 == o->branch1 ?
 950                                                         NULL : ren1->pair->two, 1);
 951                         } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 952                                 const char *new_path;
 953                                 clean_merge = 0;
 954                                 try_merge = 1;
 955                                 output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 956                                        "%s added in %s",
 957                                        ren1_src, ren1_dst, branch1,
 958                                        ren1_dst, branch2);
 959                                 if (o->call_depth) {
 960                                         struct merge_file_info mfi;
 961                                         struct diff_filespec one, a, b;
 962
 963                                         one.path = a.path = b.path =
 964                                                 (char *)ren1_dst;
 965                                         hashcpy(one.sha1, null_sha1);
 966                                         one.mode = 0;
 967                                         hashcpy(a.sha1, ren1->pair->two->sha1);
 968                                         a.mode = ren1->pair->two->mode;
 969                                         hashcpy(b.sha1, dst_other.sha1);
 970                                         b.mode = dst_other.mode;
 971                                         mfi = merge_file(o, &one, &a, &b,
 972                                                          branch1,
 973                                                          branch2);
 974                                         output(o, 1, "Adding merged %s", ren1_dst);
 975                                         update_file(o, 0,
 976                                                     mfi.sha,
 977                                                     mfi.mode,
 978                                                     ren1_dst);
 979                                 } else {
 980                                         new_path = unique_path(o, ren1_dst, branch2);
 981                                         output(o, 1, "Adding as %s instead", new_path);
 982                                         update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 983                                 }
 984                         } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 985                                 ren2 = item->util;
 986                                 clean_merge = 0;
 987                                 ren2->processed = 1;
 988                                 output(o, 1, "CONFLICT (rename/rename): "
 989                                        "Rename %s->%s in %s. "
 990                                        "Rename %s->%s in %s",
 991                                        ren1_src, ren1_dst, branch1,
 992                                        ren2->pair->one->path, ren2->pair->two->path, branch2);
 993                                 conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
 994                         } else
 995                                 try_merge = 1;
 996
 997                         if (try_merge) {
 998                                 struct diff_filespec *one, *a, *b;
 999                                 struct merge_file_info mfi;
1000                                 src_other.path = (char *)ren1_src;
1001
1002                                 one = ren1->pair->one;
1003                                 if (a_renames == renames1) {
1004                                         a = ren1->pair->two;
1005                                         b = &src_other;
1006                                 } else {
1007                                         b = ren1->pair->two;
1008                                         a = &src_other;
1009                                 }
1010                                 mfi = merge_file(o, one, a, b,
1011                                                 o->branch1, o->branch2);
1012
1013                                 if (mfi.clean &&
1014                                     sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1015                                     mfi.mode == ren1->pair->two->mode)
1016                                         /*
1017                                          * This messaged is part of
1018                                          * t6022 test. If you change
1019                                          * it update the test too.
1020                                          */
1021                                         output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1022                                 else {
1023                                         if (mfi.merge || !mfi.clean)
1024                                                 output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1025                                         if (mfi.merge)
1026                                                 output(o, 2, "Auto-merging %s", ren1_dst);
1027                                         if (!mfi.clean) {
1028                                                 output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1029                                                        ren1_dst);
1030                                                 clean_merge = 0;
1031
1032                                                 if (!o->call_depth)
1033                                                         update_stages(ren1_dst,
1034                                                                       one, a, b, 1);
1035                                         }
1036                                         update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1037                                 }
1038                         }
1039                 }
1040         }
1041         string_list_clear(&a_by_dst, 0);
1042         string_list_clear(&b_by_dst, 0);
1043
1044         return clean_merge;
1045 }
1046
1047 static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1048 {
1049         return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1050 }
1051
1052 /* Per entry merge function */
1053 static int process_entry(struct merge_options *o,
1054                          const char *path, struct stage_data *entry)
1055 {
1056         /*
1057         printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1058         print_index_entry("\tpath: ", entry);
1059         */
1060         int clean_merge = 1;
1061         unsigned o_mode = entry->stages[1].mode;
1062         unsigned a_mode = entry->stages[2].mode;
1063         unsigned b_mode = entry->stages[3].mode;
1064         unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1065         unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1066         unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1067
1068         if (o_sha && (!a_sha || !b_sha)) {
1069                 /* Case A: Deleted in one */
1070                 if ((!a_sha && !b_sha) ||
1071                     (sha_eq(a_sha, o_sha) && !b_sha) ||
1072                     (!a_sha && sha_eq(b_sha, o_sha))) {
1073                         /* Deleted in both or deleted in one and
1074                          * unchanged in the other */
1075                         if (a_sha)
1076                                 output(o, 2, "Removing %s", path);
1077                         /* do not touch working file if it did not exist */
1078                         remove_file(o, 1, path, !a_sha);
1079                 } else {
1080                         /* Deleted in one and changed in the other */
1081                         clean_merge = 0;
1082                         if (!a_sha) {
1083                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1084                                        "and modified in %s. Version %s of %s left in tree.",
1085                                        path, o->branch1,
1086                                        o->branch2, o->branch2, path);
1087                                 update_file(o, 0, b_sha, b_mode, path);
1088                         } else {
1089                                 output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1090                                        "and modified in %s. Version %s of %s left in tree.",
1091                                        path, o->branch2,
1092                                        o->branch1, o->branch1, path);
1093                                 update_file(o, 0, a_sha, a_mode, path);
1094                         }
1095                 }
1096
1097         } else if ((!o_sha && a_sha && !b_sha) ||
1098                    (!o_sha && !a_sha && b_sha)) {
1099                 /* Case B: Added in one. */
1100                 const char *add_branch;
1101                 const char *other_branch;
1102                 unsigned mode;
1103                 const unsigned char *sha;
1104                 const char *conf;
1105
1106                 if (a_sha) {
1107                         add_branch = o->branch1;
1108                         other_branch = o->branch2;
1109                         mode = a_mode;
1110                         sha = a_sha;
1111                         conf = "file/directory";
1112                 } else {
1113                         add_branch = o->branch2;
1114                         other_branch = o->branch1;
1115                         mode = b_mode;
1116                         sha = b_sha;
1117                         conf = "directory/file";
1118                 }
1119                 if (string_list_has_string(&o->current_directory_set, path)) {
1120                         const char *new_path = unique_path(o, path, add_branch);
1121                         clean_merge = 0;
1122                         output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1123                                "Adding %s as %s",
1124                                conf, path, other_branch, path, new_path);
1125                         remove_file(o, 0, path, 0);
1126                         update_file(o, 0, sha, mode, new_path);
1127                 } else {
1128                         output(o, 2, "Adding %s", path);
1129                         update_file(o, 1, sha, mode, path);
1130                 }
1131         } else if (a_sha && b_sha) {
1132                 /* Case C: Added in both (check for same permissions) and */
1133                 /* case D: Modified in both, but differently. */
1134                 const char *reason = "content";
1135                 struct merge_file_info mfi;
1136                 struct diff_filespec one, a, b;
1137
1138                 if (!o_sha) {
1139                         reason = "add/add";
1140                         o_sha = (unsigned char *)null_sha1;
1141                 }
1142                 output(o, 2, "Auto-merging %s", path);
1143                 one.path = a.path = b.path = (char *)path;
1144                 hashcpy(one.sha1, o_sha);
1145                 one.mode = o_mode;
1146                 hashcpy(a.sha1, a_sha);
1147                 a.mode = a_mode;
1148                 hashcpy(b.sha1, b_sha);
1149                 b.mode = b_mode;
1150
1151                 mfi = merge_file(o, &one, &a, &b,
1152                                  o->branch1, o->branch2);
1153
1154                 clean_merge = mfi.clean;
1155                 if (!mfi.clean) {
1156                         if (S_ISGITLINK(mfi.mode))
1157                                 reason = "submodule";
1158                         output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1159                                         reason, path);
1160                 }
1161                 update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1162         } else if (!o_sha && !a_sha && !b_sha) {
1163                 /*
1164                  * this entry was deleted altogether. a_mode == 0 means
1165                  * we had that path and want to actively remove it.
1166                  */
1167                 remove_file(o, 1, path, !a_mode);
1168         } else
1169                 die("Fatal merge failure, shouldn't happen.");
1170
1171         return clean_merge;
1172 }
1173
1174 struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
1175 {
1176         struct unpack_trees_error_msgs msgs = {
1177                 /* would_overwrite */
1178                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1179                 /* not_uptodate_file */
1180                 "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1181                 /* not_uptodate_dir */
1182                 "Updating '%s' would lose untracked files in it.  Aborting.",
1183                 /* would_lose_untracked */
1184                 "Untracked working tree file '%s' would be %s by merge.  Aborting",
1185                 /* bind_overlap -- will not happen here */
1186                 NULL,
1187         };
1188         if (advice_commit_before_merge) {
1189                 msgs.would_overwrite = msgs.not_uptodate_file =
1190                         "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
1191                         "Please, commit your changes or stash them before you can merge.";
1192         }
1193         return msgs;
1194 }
1195
1196 int merge_trees(struct merge_options *o,
1197                 struct tree *head,
1198                 struct tree *merge,
1199                 struct tree *common,
1200                 struct tree **result)
1201 {
1202         int code, clean;
1203
1204         if (o->subtree_merge) {
1205                 merge = shift_tree_object(head, merge);
1206                 common = shift_tree_object(head, common);
1207         }
1208
1209         if (sha_eq(common->object.sha1, merge->object.sha1)) {
1210                 output(o, 0, "Already uptodate!");
1211                 *result = head;
1212                 return 1;
1213         }
1214
1215         code = git_merge_trees(o->call_depth, common, head, merge);
1216
1217         if (code != 0) {
1218                 if (show(o, 4) || o->call_depth)
1219                         die("merging of trees %s and %s failed",
1220                             sha1_to_hex(head->object.sha1),
1221                             sha1_to_hex(merge->object.sha1));
1222                 else
1223                         exit(128);
1224         }
1225
1226         if (unmerged_cache()) {
1227                 struct string_list *entries, *re_head, *re_merge;
1228                 int i;
1229                 string_list_clear(&o->current_file_set, 1);
1230                 string_list_clear(&o->current_directory_set, 1);
1231                 get_files_dirs(o, head);
1232                 get_files_dirs(o, merge);
1233
1234                 entries = get_unmerged();
1235                 re_head  = get_renames(o, head, common, head, merge, entries);
1236                 re_merge = get_renames(o, merge, common, head, merge, entries);
1237                 clean = process_renames(o, re_head, re_merge);
1238                 for (i = 0; i < entries->nr; i++) {
1239                         const char *path = entries->items[i].string;
1240                         struct stage_data *e = entries->items[i].util;
1241                         if (!e->processed
1242                                 && !process_entry(o, path, e))
1243                                 clean = 0;
1244                 }
1245
1246                 string_list_clear(re_merge, 0);
1247                 string_list_clear(re_head, 0);
1248                 string_list_clear(entries, 1);
1249
1250         }
1251         else
1252                 clean = 1;
1253
1254         if (o->call_depth)
1255                 *result = write_tree_from_memory(o);
1256
1257         return clean;
1258 }
1259
1260 static struct commit_list *reverse_commit_list(struct commit_list *list)
1261 {
1262         struct commit_list *next = NULL, *current, *backup;
1263         for (current = list; current; current = backup) {
1264                 backup = current->next;
1265                 current->next = next;
1266                 next = current;
1267         }
1268         return next;
1269 }
1270
1271 /*
1272  * Merge the commits h1 and h2, return the resulting virtual
1273  * commit object and a flag indicating the cleanness of the merge.
1274  */
1275 int merge_recursive(struct merge_options *o,
1276                     struct commit *h1,
1277                     struct commit *h2,
1278                     struct commit_list *ca,
1279                     struct commit **result)
1280 {
1281         struct commit_list *iter;
1282         struct commit *merged_common_ancestors;
1283         struct tree *mrtree = mrtree;
1284         int clean;
1285
1286         if (show(o, 4)) {
1287                 output(o, 4, "Merging:");
1288                 output_commit_title(o, h1);
1289                 output_commit_title(o, h2);
1290         }
1291
1292         if (!ca) {
1293                 ca = get_merge_bases(h1, h2, 1);
1294                 ca = reverse_commit_list(ca);
1295         }
1296
1297         if (show(o, 5)) {
1298                 output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1299                 for (iter = ca; iter; iter = iter->next)
1300                         output_commit_title(o, iter->item);
1301         }
1302
1303         merged_common_ancestors = pop_commit(&ca);
1304         if (merged_common_ancestors == NULL) {
1305                 /* if there is no common ancestor, make an empty tree */
1306                 struct tree *tree = xcalloc(1, sizeof(struct tree));
1307
1308                 tree->object.parsed = 1;
1309                 tree->object.type = OBJ_TREE;
1310                 pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1311                 merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1312         }
1313
1314         for (iter = ca; iter; iter = iter->next) {
1315                 const char *saved_b1, *saved_b2;
1316                 o->call_depth++;
1317                 /*
1318                  * When the merge fails, the result contains files
1319                  * with conflict markers. The cleanness flag is
1320                  * ignored, it was never actually used, as result of
1321                  * merge_trees has always overwritten it: the committed
1322                  * "conflicts" were already resolved.
1323                  */
1324                 discard_cache();
1325                 saved_b1 = o->branch1;
1326                 saved_b2 = o->branch2;
1327                 o->branch1 = "Temporary merge branch 1";
1328                 o->branch2 = "Temporary merge branch 2";
1329                 merge_recursive(o, merged_common_ancestors, iter->item,
1330                                 NULL, &merged_common_ancestors);
1331                 o->branch1 = saved_b1;
1332                 o->branch2 = saved_b2;
1333                 o->call_depth--;
1334
1335                 if (!merged_common_ancestors)
1336                         die("merge returned no commit");
1337         }
1338
1339         discard_cache();
1340         if (!o->call_depth)
1341                 read_cache();
1342
1343         clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1344                             &mrtree);
1345
1346         if (o->call_depth) {
1347                 *result = make_virtual_commit(mrtree, "merged tree");
1348                 commit_list_insert(h1, &(*result)->parents);
1349                 commit_list_insert(h2, &(*result)->parents->next);
1350         }
1351         flush_output(o);
1352         return clean;
1353 }
1354
1355 static struct commit *get_ref(const unsigned char *sha1, const char *name)
1356 {
1357         struct object *object;
1358
1359         object = deref_tag(parse_object(sha1), name, strlen(name));
1360         if (!object)
1361                 return NULL;
1362         if (object->type == OBJ_TREE)
1363                 return make_virtual_commit((struct tree*)object, name);
1364         if (object->type != OBJ_COMMIT)
1365                 return NULL;
1366         if (parse_commit((struct commit *)object))
1367                 return NULL;
1368         return (struct commit *)object;
1369 }
1370
1371 int merge_recursive_generic(struct merge_options *o,
1372                             const unsigned char *head,
1373                             const unsigned char *merge,
1374                             int num_base_list,
1375                             const unsigned char **base_list,
1376                             struct commit **result)
1377 {
1378         int clean, index_fd;
1379         struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1380         struct commit *head_commit = get_ref(head, o->branch1);
1381         struct commit *next_commit = get_ref(merge, o->branch2);
1382         struct commit_list *ca = NULL;
1383
1384         if (base_list) {
1385                 int i;
1386                 for (i = 0; i < num_base_list; ++i) {
1387                         struct commit *base;
1388                         if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1389                                 return error("Could not parse object '%s'",
1390                                         sha1_to_hex(base_list[i]));
1391                         commit_list_insert(base, &ca);
1392                 }
1393         }
1394
1395         index_fd = hold_locked_index(lock, 1);
1396         clean = merge_recursive(o, head_commit, next_commit, ca,
1397                         result);
1398         if (active_cache_changed &&
1399                         (write_cache(index_fd, active_cache, active_nr) ||
1400                          commit_locked_index(lock)))
1401                 return error("Unable to write index.");
1402
1403         return clean ? 0 : 1;
1404 }
1405
1406 static int merge_recursive_config(const char *var, const char *value, void *cb)
1407 {
1408         struct merge_options *o = cb;
1409         if (!strcasecmp(var, "merge.verbosity")) {
1410                 o->verbosity = git_config_int(var, value);
1411                 return 0;
1412         }
1413         if (!strcasecmp(var, "diff.renamelimit")) {
1414                 o->diff_rename_limit = git_config_int(var, value);
1415                 return 0;
1416         }
1417         if (!strcasecmp(var, "merge.renamelimit")) {
1418                 o->merge_rename_limit = git_config_int(var, value);
1419                 return 0;
1420         }
1421         return git_xmerge_config(var, value, cb);
1422 }
1423
1424 void init_merge_options(struct merge_options *o)
1425 {
1426         memset(o, 0, sizeof(struct merge_options));
1427         o->verbosity = 2;
1428         o->buffer_output = 1;
1429         o->diff_rename_limit = -1;
1430         o->merge_rename_limit = -1;
1431         git_config(merge_recursive_config, o);
1432         if (getenv("GIT_MERGE_VERBOSITY"))
1433                 o->verbosity =
1434                         strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1435         if (o->verbosity >= 5)
1436                 o->buffer_output = 0;
1437         strbuf_init(&o->obuf, 0);
1438         memset(&o->current_file_set, 0, sizeof(struct string_list));
1439         o->current_file_set.strdup_strings = 1;
1440         memset(&o->current_directory_set, 0, sizeof(struct string_list));
1441         o->current_directory_set.strdup_strings = 1;
1442 }