merge-recursive.con commit git-p4: fix bug in symlink handling (b39c361)
   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
  24static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  25                                      const char *subtree_shift)
  26{
  27        unsigned char shifted[20];
  28
  29        if (!*subtree_shift) {
  30                shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  31        } else {
  32                shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  33                              subtree_shift);
  34        }
  35        if (!hashcmp(two->object.sha1, shifted))
  36                return two;
  37        return lookup_tree(shifted);
  38}
  39
  40/*
  41 * A virtual commit has (const char *)commit->util set to the name.
  42 */
  43
  44static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  45{
  46        struct commit *commit = xcalloc(1, sizeof(struct commit));
  47        commit->tree = tree;
  48        commit->util = (void*)comment;
  49        /* avoid warnings */
  50        commit->object.parsed = 1;
  51        return commit;
  52}
  53
  54/*
  55 * Since we use get_tree_entry(), which does not put the read object into
  56 * the object pool, we cannot rely on a == b.
  57 */
  58static int sha_eq(const unsigned char *a, const unsigned char *b)
  59{
  60        if (!a && !b)
  61                return 2;
  62        return a && b && hashcmp(a, b) == 0;
  63}
  64
  65/*
  66 * Since we want to write the index eventually, we cannot reuse the index
  67 * for these (temporary) data.
  68 */
  69struct stage_data
  70{
  71        struct
  72        {
  73                unsigned mode;
  74                unsigned char sha[20];
  75        } stages[4];
  76        unsigned processed:1;
  77};
  78
  79static int show(struct merge_options *o, int v)
  80{
  81        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  82}
  83
  84static void flush_output(struct merge_options *o)
  85{
  86        if (o->obuf.len) {
  87                fputs(o->obuf.buf, stdout);
  88                strbuf_reset(&o->obuf);
  89        }
  90}
  91
  92__attribute__((format (printf, 3, 4)))
  93static void output(struct merge_options *o, int v, const char *fmt, ...)
  94{
  95        int len;
  96        va_list ap;
  97
  98        if (!show(o, v))
  99                return;
 100
 101        strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 102        memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 103        strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 104
 105        va_start(ap, fmt);
 106        len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 107        va_end(ap);
 108
 109        if (len < 0)
 110                len = 0;
 111        if (len >= strbuf_avail(&o->obuf)) {
 112                strbuf_grow(&o->obuf, len + 2);
 113                va_start(ap, fmt);
 114                len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 115                va_end(ap);
 116                if (len >= strbuf_avail(&o->obuf)) {
 117                        die("this should not happen, your snprintf is broken");
 118                }
 119        }
 120        strbuf_setlen(&o->obuf, o->obuf.len + len);
 121        strbuf_add(&o->obuf, "\n", 1);
 122        if (!o->buffer_output)
 123                flush_output(o);
 124}
 125
 126static void output_commit_title(struct merge_options *o, struct commit *commit)
 127{
 128        int i;
 129        flush_output(o);
 130        for (i = o->call_depth; i--;)
 131                fputs("  ", stdout);
 132        if (commit->util)
 133                printf("virtual %s\n", (char *)commit->util);
 134        else {
 135                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 136                if (parse_commit(commit) != 0)
 137                        printf("(bad commit)\n");
 138                else {
 139                        const char *s;
 140                        int len;
 141                        for (s = commit->buffer; *s; s++)
 142                                if (*s == '\n' && s[1] == '\n') {
 143                                        s += 2;
 144                                        break;
 145                                }
 146                        for (len = 0; s[len] && '\n' != s[len]; len++)
 147                                ; /* do nothing */
 148                        printf("%.*s\n", len, s);
 149                }
 150        }
 151}
 152
 153static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 154                const char *path, int stage, int refresh, int options)
 155{
 156        struct cache_entry *ce;
 157        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 158        if (!ce)
 159                return error("addinfo_cache failed for path '%s'", path);
 160        return add_cache_entry(ce, options);
 161}
 162
 163static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 164{
 165        parse_tree(tree);
 166        init_tree_desc(desc, tree->buffer, tree->size);
 167}
 168
 169static int git_merge_trees(int index_only,
 170                           struct tree *common,
 171                           struct tree *head,
 172                           struct tree *merge)
 173{
 174        int rc;
 175        struct tree_desc t[3];
 176        struct unpack_trees_options opts;
 177
 178        memset(&opts, 0, sizeof(opts));
 179        if (index_only)
 180                opts.index_only = 1;
 181        else
 182                opts.update = 1;
 183        opts.merge = 1;
 184        opts.head_idx = 2;
 185        opts.fn = threeway_merge;
 186        opts.src_index = &the_index;
 187        opts.dst_index = &the_index;
 188        opts.msgs = get_porcelain_error_msgs();
 189
 190        init_tree_desc_from_tree(t+0, common);
 191        init_tree_desc_from_tree(t+1, head);
 192        init_tree_desc_from_tree(t+2, merge);
 193
 194        rc = unpack_trees(3, t, &opts);
 195        cache_tree_free(&active_cache_tree);
 196        return rc;
 197}
 198
 199struct tree *write_tree_from_memory(struct merge_options *o)
 200{
 201        struct tree *result = NULL;
 202
 203        if (unmerged_cache()) {
 204                int i;
 205                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 206                for (i = 0; i < active_nr; i++) {
 207                        struct cache_entry *ce = active_cache[i];
 208                        if (ce_stage(ce))
 209                                fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 210                                        (int)ce_namelen(ce), ce->name);
 211                }
 212                die("Bug in merge-recursive.c");
 213        }
 214
 215        if (!active_cache_tree)
 216                active_cache_tree = cache_tree();
 217
 218        if (!cache_tree_fully_valid(active_cache_tree) &&
 219            cache_tree_update(active_cache_tree,
 220                              active_cache, active_nr, 0, 0) < 0)
 221                die("error building trees");
 222
 223        result = lookup_tree(active_cache_tree->sha1);
 224
 225        return result;
 226}
 227
 228static int save_files_dirs(const unsigned char *sha1,
 229                const char *base, int baselen, const char *path,
 230                unsigned int mode, int stage, void *context)
 231{
 232        int len = strlen(path);
 233        char *newpath = xmalloc(baselen + len + 1);
 234        struct merge_options *o = context;
 235
 236        memcpy(newpath, base, baselen);
 237        memcpy(newpath + baselen, path, len);
 238        newpath[baselen + len] = '\0';
 239
 240        if (S_ISDIR(mode))
 241                string_list_insert(newpath, &o->current_directory_set);
 242        else
 243                string_list_insert(newpath, &o->current_file_set);
 244        free(newpath);
 245
 246        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 247}
 248
 249static int get_files_dirs(struct merge_options *o, struct tree *tree)
 250{
 251        int n;
 252        if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 253                return 0;
 254        n = o->current_file_set.nr + o->current_directory_set.nr;
 255        return n;
 256}
 257
 258/*
 259 * Returns an index_entry instance which doesn't have to correspond to
 260 * a real cache entry in Git's index.
 261 */
 262static struct stage_data *insert_stage_data(const char *path,
 263                struct tree *o, struct tree *a, struct tree *b,
 264                struct string_list *entries)
 265{
 266        struct string_list_item *item;
 267        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 268        get_tree_entry(o->object.sha1, path,
 269                        e->stages[1].sha, &e->stages[1].mode);
 270        get_tree_entry(a->object.sha1, path,
 271                        e->stages[2].sha, &e->stages[2].mode);
 272        get_tree_entry(b->object.sha1, path,
 273                        e->stages[3].sha, &e->stages[3].mode);
 274        item = string_list_insert(path, entries);
 275        item->util = e;
 276        return e;
 277}
 278
 279/*
 280 * Create a dictionary mapping file names to stage_data objects. The
 281 * dictionary contains one entry for every path with a non-zero stage entry.
 282 */
 283static struct string_list *get_unmerged(void)
 284{
 285        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 286        int i;
 287
 288        unmerged->strdup_strings = 1;
 289
 290        for (i = 0; i < active_nr; i++) {
 291                struct string_list_item *item;
 292                struct stage_data *e;
 293                struct cache_entry *ce = active_cache[i];
 294                if (!ce_stage(ce))
 295                        continue;
 296
 297                item = string_list_lookup(ce->name, unmerged);
 298                if (!item) {
 299                        item = string_list_insert(ce->name, unmerged);
 300                        item->util = xcalloc(1, sizeof(struct stage_data));
 301                }
 302                e = item->util;
 303                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 304                hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 305        }
 306
 307        return unmerged;
 308}
 309
 310struct rename
 311{
 312        struct diff_filepair *pair;
 313        struct stage_data *src_entry;
 314        struct stage_data *dst_entry;
 315        unsigned processed:1;
 316};
 317
 318/*
 319 * Get information of all renames which occurred between 'o_tree' and
 320 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 321 * 'b_tree') to be able to associate the correct cache entries with
 322 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 323 */
 324static struct string_list *get_renames(struct merge_options *o,
 325                                       struct tree *tree,
 326                                       struct tree *o_tree,
 327                                       struct tree *a_tree,
 328                                       struct tree *b_tree,
 329                                       struct string_list *entries)
 330{
 331        int i;
 332        struct string_list *renames;
 333        struct diff_options opts;
 334
 335        renames = xcalloc(1, sizeof(struct string_list));
 336        diff_setup(&opts);
 337        DIFF_OPT_SET(&opts, RECURSIVE);
 338        opts.detect_rename = DIFF_DETECT_RENAME;
 339        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 340                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 341                            500;
 342        opts.warn_on_too_large_rename = 1;
 343        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 344        if (diff_setup_done(&opts) < 0)
 345                die("diff setup failed");
 346        diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 347        diffcore_std(&opts);
 348        for (i = 0; i < diff_queued_diff.nr; ++i) {
 349                struct string_list_item *item;
 350                struct rename *re;
 351                struct diff_filepair *pair = diff_queued_diff.queue[i];
 352                if (pair->status != 'R') {
 353                        diff_free_filepair(pair);
 354                        continue;
 355                }
 356                re = xmalloc(sizeof(*re));
 357                re->processed = 0;
 358                re->pair = pair;
 359                item = string_list_lookup(re->pair->one->path, entries);
 360                if (!item)
 361                        re->src_entry = insert_stage_data(re->pair->one->path,
 362                                        o_tree, a_tree, b_tree, entries);
 363                else
 364                        re->src_entry = item->util;
 365
 366                item = string_list_lookup(re->pair->two->path, entries);
 367                if (!item)
 368                        re->dst_entry = insert_stage_data(re->pair->two->path,
 369                                        o_tree, a_tree, b_tree, entries);
 370                else
 371                        re->dst_entry = item->util;
 372                item = string_list_insert(pair->one->path, renames);
 373                item->util = re;
 374        }
 375        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 376        diff_queued_diff.nr = 0;
 377        diff_flush(&opts);
 378        return renames;
 379}
 380
 381static int update_stages(const char *path, struct diff_filespec *o,
 382                         struct diff_filespec *a, struct diff_filespec *b,
 383                         int clear)
 384{
 385        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 386        if (clear)
 387                if (remove_file_from_cache(path))
 388                        return -1;
 389        if (o)
 390                if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 391                        return -1;
 392        if (a)
 393                if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 394                        return -1;
 395        if (b)
 396                if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 397                        return -1;
 398        return 0;
 399}
 400
 401static int remove_file(struct merge_options *o, int clean,
 402                       const char *path, int no_wd)
 403{
 404        int update_cache = o->call_depth || clean;
 405        int update_working_directory = !o->call_depth && !no_wd;
 406
 407        if (update_cache) {
 408                if (remove_file_from_cache(path))
 409                        return -1;
 410        }
 411        if (update_working_directory) {
 412                if (remove_path(path) && errno != ENOENT)
 413                        return -1;
 414        }
 415        return 0;
 416}
 417
 418static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 419{
 420        char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 421        int suffix = 0;
 422        struct stat st;
 423        char *p = newpath + strlen(path);
 424        strcpy(newpath, path);
 425        *(p++) = '~';
 426        strcpy(p, branch);
 427        for (; *p; ++p)
 428                if ('/' == *p)
 429                        *p = '_';
 430        while (string_list_has_string(&o->current_file_set, newpath) ||
 431               string_list_has_string(&o->current_directory_set, newpath) ||
 432               lstat(newpath, &st) == 0)
 433                sprintf(p, "_%d", suffix++);
 434
 435        string_list_insert(newpath, &o->current_file_set);
 436        return newpath;
 437}
 438
 439static void flush_buffer(int fd, const char *buf, unsigned long size)
 440{
 441        while (size > 0) {
 442                long ret = write_in_full(fd, buf, size);
 443                if (ret < 0) {
 444                        /* Ignore epipe */
 445                        if (errno == EPIPE)
 446                                break;
 447                        die_errno("merge-recursive");
 448                } else if (!ret) {
 449                        die("merge-recursive: disk full?");
 450                }
 451                size -= ret;
 452                buf += ret;
 453        }
 454}
 455
 456static int would_lose_untracked(const char *path)
 457{
 458        int pos = cache_name_pos(path, strlen(path));
 459
 460        if (pos < 0)
 461                pos = -1 - pos;
 462        while (pos < active_nr &&
 463               !strcmp(path, active_cache[pos]->name)) {
 464                /*
 465                 * If stage #0, it is definitely tracked.
 466                 * If it has stage #2 then it was tracked
 467                 * before this merge started.  All other
 468                 * cases the path was not tracked.
 469                 */
 470                switch (ce_stage(active_cache[pos])) {
 471                case 0:
 472                case 2:
 473                        return 0;
 474                }
 475                pos++;
 476        }
 477        return file_exists(path);
 478}
 479
 480static int make_room_for_path(const char *path)
 481{
 482        int status;
 483        const char *msg = "failed to create path '%s'%s";
 484
 485        status = safe_create_leading_directories_const(path);
 486        if (status) {
 487                if (status == -3) {
 488                        /* something else exists */
 489                        error(msg, path, ": perhaps a D/F conflict?");
 490                        return -1;
 491                }
 492                die(msg, path, "");
 493        }
 494
 495        /*
 496         * Do not unlink a file in the work tree if we are not
 497         * tracking it.
 498         */
 499        if (would_lose_untracked(path))
 500                return error("refusing to lose untracked file at '%s'",
 501                             path);
 502
 503        /* Successful unlink is good.. */
 504        if (!unlink(path))
 505                return 0;
 506        /* .. and so is no existing file */
 507        if (errno == ENOENT)
 508                return 0;
 509        /* .. but not some other error (who really cares what?) */
 510        return error(msg, path, ": perhaps a D/F conflict?");
 511}
 512
 513static void update_file_flags(struct merge_options *o,
 514                              const unsigned char *sha,
 515                              unsigned mode,
 516                              const char *path,
 517                              int update_cache,
 518                              int update_wd)
 519{
 520        if (o->call_depth)
 521                update_wd = 0;
 522
 523        if (update_wd) {
 524                enum object_type type;
 525                void *buf;
 526                unsigned long size;
 527
 528                if (S_ISGITLINK(mode))
 529                        /*
 530                         * We may later decide to recursively descend into
 531                         * the submodule directory and update its index
 532                         * and/or work tree, but we do not do that now.
 533                         */
 534                        goto update_index;
 535
 536                buf = read_sha1_file(sha, &type, &size);
 537                if (!buf)
 538                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 539                if (type != OBJ_BLOB)
 540                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 541                if (S_ISREG(mode)) {
 542                        struct strbuf strbuf = STRBUF_INIT;
 543                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 544                                free(buf);
 545                                size = strbuf.len;
 546                                buf = strbuf_detach(&strbuf, NULL);
 547                        }
 548                }
 549
 550                if (make_room_for_path(path) < 0) {
 551                        update_wd = 0;
 552                        free(buf);
 553                        goto update_index;
 554                }
 555                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 556                        int fd;
 557                        if (mode & 0100)
 558                                mode = 0777;
 559                        else
 560                                mode = 0666;
 561                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 562                        if (fd < 0)
 563                                die_errno("failed to open '%s'", path);
 564                        flush_buffer(fd, buf, size);
 565                        close(fd);
 566                } else if (S_ISLNK(mode)) {
 567                        char *lnk = xmemdupz(buf, size);
 568                        safe_create_leading_directories_const(path);
 569                        unlink(path);
 570                        if (symlink(lnk, path))
 571                                die_errno("failed to symlink '%s'", path);
 572                        free(lnk);
 573                } else
 574                        die("do not know what to do with %06o %s '%s'",
 575                            mode, sha1_to_hex(sha), path);
 576                free(buf);
 577        }
 578 update_index:
 579        if (update_cache)
 580                add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 581}
 582
 583static void update_file(struct merge_options *o,
 584                        int clean,
 585                        const unsigned char *sha,
 586                        unsigned mode,
 587                        const char *path)
 588{
 589        update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 590}
 591
 592/* Low level file merging, update and removal */
 593
 594struct merge_file_info
 595{
 596        unsigned char sha[20];
 597        unsigned mode;
 598        unsigned clean:1,
 599                 merge:1;
 600};
 601
 602static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 603{
 604        unsigned long size;
 605        enum object_type type;
 606
 607        if (!hashcmp(sha1, null_sha1)) {
 608                mm->ptr = xstrdup("");
 609                mm->size = 0;
 610                return;
 611        }
 612
 613        mm->ptr = read_sha1_file(sha1, &type, &size);
 614        if (!mm->ptr || type != OBJ_BLOB)
 615                die("unable to read blob object %s", sha1_to_hex(sha1));
 616        mm->size = size;
 617}
 618
 619static int merge_3way(struct merge_options *o,
 620                      mmbuffer_t *result_buf,
 621                      struct diff_filespec *one,
 622                      struct diff_filespec *a,
 623                      struct diff_filespec *b,
 624                      const char *branch1,
 625                      const char *branch2)
 626{
 627        mmfile_t orig, src1, src2;
 628        char *name1, *name2;
 629        int merge_status;
 630        int favor;
 631
 632        if (o->call_depth)
 633                favor = 0;
 634        else {
 635                switch (o->recursive_variant) {
 636                case MERGE_RECURSIVE_OURS:
 637                        favor = XDL_MERGE_FAVOR_OURS;
 638                        break;
 639                case MERGE_RECURSIVE_THEIRS:
 640                        favor = XDL_MERGE_FAVOR_THEIRS;
 641                        break;
 642                default:
 643                        favor = 0;
 644                        break;
 645                }
 646        }
 647
 648        if (strcmp(a->path, b->path)) {
 649                name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 650                name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 651        } else {
 652                name1 = xstrdup(mkpath("%s", branch1));
 653                name2 = xstrdup(mkpath("%s", branch2));
 654        }
 655
 656        fill_mm(one->sha1, &orig);
 657        fill_mm(a->sha1, &src1);
 658        fill_mm(b->sha1, &src2);
 659
 660        merge_status = ll_merge(result_buf, a->path, &orig,
 661                                &src1, name1, &src2, name2,
 662                                (!!o->call_depth) | (favor << 1));
 663
 664        free(name1);
 665        free(name2);
 666        free(orig.ptr);
 667        free(src1.ptr);
 668        free(src2.ptr);
 669        return merge_status;
 670}
 671
 672static struct merge_file_info merge_file(struct merge_options *o,
 673                                         struct diff_filespec *one,
 674                                         struct diff_filespec *a,
 675                                         struct diff_filespec *b,
 676                                         const char *branch1,
 677                                         const char *branch2)
 678{
 679        struct merge_file_info result;
 680        result.merge = 0;
 681        result.clean = 1;
 682
 683        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 684                result.clean = 0;
 685                if (S_ISREG(a->mode)) {
 686                        result.mode = a->mode;
 687                        hashcpy(result.sha, a->sha1);
 688                } else {
 689                        result.mode = b->mode;
 690                        hashcpy(result.sha, b->sha1);
 691                }
 692        } else {
 693                if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 694                        result.merge = 1;
 695
 696                /*
 697                 * Merge modes
 698                 */
 699                if (a->mode == b->mode || a->mode == one->mode)
 700                        result.mode = b->mode;
 701                else {
 702                        result.mode = a->mode;
 703                        if (b->mode != one->mode) {
 704                                result.clean = 0;
 705                                result.merge = 1;
 706                        }
 707                }
 708
 709                if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 710                        hashcpy(result.sha, b->sha1);
 711                else if (sha_eq(b->sha1, one->sha1))
 712                        hashcpy(result.sha, a->sha1);
 713                else if (S_ISREG(a->mode)) {
 714                        mmbuffer_t result_buf;
 715                        int merge_status;
 716
 717                        merge_status = merge_3way(o, &result_buf, one, a, b,
 718                                                  branch1, branch2);
 719
 720                        if ((merge_status < 0) || !result_buf.ptr)
 721                                die("Failed to execute internal merge");
 722
 723                        if (write_sha1_file(result_buf.ptr, result_buf.size,
 724                                            blob_type, result.sha))
 725                                die("Unable to add %s to database",
 726                                    a->path);
 727
 728                        free(result_buf.ptr);
 729                        result.clean = (merge_status == 0);
 730                } else if (S_ISGITLINK(a->mode)) {
 731                        result.clean = 0;
 732                        hashcpy(result.sha, a->sha1);
 733                } else if (S_ISLNK(a->mode)) {
 734                        hashcpy(result.sha, a->sha1);
 735
 736                        if (!sha_eq(a->sha1, b->sha1))
 737                                result.clean = 0;
 738                } else {
 739                        die("unsupported object type in the tree");
 740                }
 741        }
 742
 743        return result;
 744}
 745
 746static void conflict_rename_rename(struct merge_options *o,
 747                                   struct rename *ren1,
 748                                   const char *branch1,
 749                                   struct rename *ren2,
 750                                   const char *branch2)
 751{
 752        char *del[2];
 753        int delp = 0;
 754        const char *ren1_dst = ren1->pair->two->path;
 755        const char *ren2_dst = ren2->pair->two->path;
 756        const char *dst_name1 = ren1_dst;
 757        const char *dst_name2 = ren2_dst;
 758        if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 759                dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 760                output(o, 1, "%s is a directory in %s adding as %s instead",
 761                       ren1_dst, branch2, dst_name1);
 762                remove_file(o, 0, ren1_dst, 0);
 763        }
 764        if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 765                dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 766                output(o, 1, "%s is a directory in %s adding as %s instead",
 767                       ren2_dst, branch1, dst_name2);
 768                remove_file(o, 0, ren2_dst, 0);
 769        }
 770        if (o->call_depth) {
 771                remove_file_from_cache(dst_name1);
 772                remove_file_from_cache(dst_name2);
 773                /*
 774                 * Uncomment to leave the conflicting names in the resulting tree
 775                 *
 776                 * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 777                 * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 778                 */
 779        } else {
 780                update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 781                update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 782        }
 783        while (delp--)
 784                free(del[delp]);
 785}
 786
 787static void conflict_rename_dir(struct merge_options *o,
 788                                struct rename *ren1,
 789                                const char *branch1)
 790{
 791        char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 792        output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 793        remove_file(o, 0, ren1->pair->two->path, 0);
 794        update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 795        free(new_path);
 796}
 797
 798static void conflict_rename_rename_2(struct merge_options *o,
 799                                     struct rename *ren1,
 800                                     const char *branch1,
 801                                     struct rename *ren2,
 802                                     const char *branch2)
 803{
 804        char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 805        char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 806        output(o, 1, "Renaming %s to %s and %s to %s instead",
 807               ren1->pair->one->path, new_path1,
 808               ren2->pair->one->path, new_path2);
 809        remove_file(o, 0, ren1->pair->two->path, 0);
 810        update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 811        update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 812        free(new_path2);
 813        free(new_path1);
 814}
 815
 816static int process_renames(struct merge_options *o,
 817                           struct string_list *a_renames,
 818                           struct string_list *b_renames)
 819{
 820        int clean_merge = 1, i, j;
 821        struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 822        const struct rename *sre;
 823
 824        for (i = 0; i < a_renames->nr; i++) {
 825                sre = a_renames->items[i].util;
 826                string_list_insert(sre->pair->two->path, &a_by_dst)->util
 827                        = sre->dst_entry;
 828        }
 829        for (i = 0; i < b_renames->nr; i++) {
 830                sre = b_renames->items[i].util;
 831                string_list_insert(sre->pair->two->path, &b_by_dst)->util
 832                        = sre->dst_entry;
 833        }
 834
 835        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 836                char *src;
 837                struct string_list *renames1, *renames2Dst;
 838                struct rename *ren1 = NULL, *ren2 = NULL;
 839                const char *branch1, *branch2;
 840                const char *ren1_src, *ren1_dst;
 841
 842                if (i >= a_renames->nr) {
 843                        ren2 = b_renames->items[j++].util;
 844                } else if (j >= b_renames->nr) {
 845                        ren1 = a_renames->items[i++].util;
 846                } else {
 847                        int compare = strcmp(a_renames->items[i].string,
 848                                             b_renames->items[j].string);
 849                        if (compare <= 0)
 850                                ren1 = a_renames->items[i++].util;
 851                        if (compare >= 0)
 852                                ren2 = b_renames->items[j++].util;
 853                }
 854
 855                /* TODO: refactor, so that 1/2 are not needed */
 856                if (ren1) {
 857                        renames1 = a_renames;
 858                        renames2Dst = &b_by_dst;
 859                        branch1 = o->branch1;
 860                        branch2 = o->branch2;
 861                } else {
 862                        struct rename *tmp;
 863                        renames1 = b_renames;
 864                        renames2Dst = &a_by_dst;
 865                        branch1 = o->branch2;
 866                        branch2 = o->branch1;
 867                        tmp = ren2;
 868                        ren2 = ren1;
 869                        ren1 = tmp;
 870                }
 871                src = ren1->pair->one->path;
 872
 873                ren1->dst_entry->processed = 1;
 874                ren1->src_entry->processed = 1;
 875
 876                if (ren1->processed)
 877                        continue;
 878                ren1->processed = 1;
 879
 880                ren1_src = ren1->pair->one->path;
 881                ren1_dst = ren1->pair->two->path;
 882
 883                if (ren2) {
 884                        const char *ren2_src = ren2->pair->one->path;
 885                        const char *ren2_dst = ren2->pair->two->path;
 886                        /* Renamed in 1 and renamed in 2 */
 887                        if (strcmp(ren1_src, ren2_src) != 0)
 888                                die("ren1.src != ren2.src");
 889                        ren2->dst_entry->processed = 1;
 890                        ren2->processed = 1;
 891                        if (strcmp(ren1_dst, ren2_dst) != 0) {
 892                                clean_merge = 0;
 893                                output(o, 1, "CONFLICT (rename/rename): "
 894                                       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 895                                       "rename \"%s\"->\"%s\" in \"%s\"%s",
 896                                       src, ren1_dst, branch1,
 897                                       src, ren2_dst, branch2,
 898                                       o->call_depth ? " (left unresolved)": "");
 899                                if (o->call_depth) {
 900                                        remove_file_from_cache(src);
 901                                        update_file(o, 0, ren1->pair->one->sha1,
 902                                                    ren1->pair->one->mode, src);
 903                                }
 904                                conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 905                        } else {
 906                                struct merge_file_info mfi;
 907                                remove_file(o, 1, ren1_src, 1);
 908                                mfi = merge_file(o,
 909                                                 ren1->pair->one,
 910                                                 ren1->pair->two,
 911                                                 ren2->pair->two,
 912                                                 branch1,
 913                                                 branch2);
 914                                if (mfi.merge || !mfi.clean)
 915                                        output(o, 1, "Renaming %s->%s", src, ren1_dst);
 916
 917                                if (mfi.merge)
 918                                        output(o, 2, "Auto-merging %s", ren1_dst);
 919
 920                                if (!mfi.clean) {
 921                                        output(o, 1, "CONFLICT (content): merge conflict in %s",
 922                                               ren1_dst);
 923                                        clean_merge = 0;
 924
 925                                        if (!o->call_depth)
 926                                                update_stages(ren1_dst,
 927                                                              ren1->pair->one,
 928                                                              ren1->pair->two,
 929                                                              ren2->pair->two,
 930                                                              1 /* clear */);
 931                                }
 932                                update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 933                        }
 934                } else {
 935                        /* Renamed in 1, maybe changed in 2 */
 936                        struct string_list_item *item;
 937                        /* we only use sha1 and mode of these */
 938                        struct diff_filespec src_other, dst_other;
 939                        int try_merge, stage = a_renames == renames1 ? 3: 2;
 940
 941                        remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 942
 943                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 944                        src_other.mode = ren1->src_entry->stages[stage].mode;
 945                        hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 946                        dst_other.mode = ren1->dst_entry->stages[stage].mode;
 947
 948                        try_merge = 0;
 949
 950                        if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 951                                clean_merge = 0;
 952                                output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 953                                       " directory %s added in %s",
 954                                       ren1_src, ren1_dst, branch1,
 955                                       ren1_dst, branch2);
 956                                conflict_rename_dir(o, ren1, branch1);
 957                        } else if (sha_eq(src_other.sha1, null_sha1)) {
 958                                clean_merge = 0;
 959                                output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 960                                       "and deleted in %s",
 961                                       ren1_src, ren1_dst, branch1,
 962                                       branch2);
 963                                update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 964                                if (!o->call_depth)
 965                                        update_stages(ren1_dst, NULL,
 966                                                        branch1 == o->branch1 ?
 967                                                        ren1->pair->two : NULL,
 968                                                        branch1 == o->branch1 ?
 969                                                        NULL : ren1->pair->two, 1);
 970                        } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 971                                const char *new_path;
 972                                clean_merge = 0;
 973                                try_merge = 1;
 974                                output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 975                                       "%s added in %s",
 976                                       ren1_src, ren1_dst, branch1,
 977                                       ren1_dst, branch2);
 978                                if (o->call_depth) {
 979                                        struct merge_file_info mfi;
 980                                        struct diff_filespec one, a, b;
 981
 982                                        one.path = a.path = b.path =
 983                                                (char *)ren1_dst;
 984                                        hashcpy(one.sha1, null_sha1);
 985                                        one.mode = 0;
 986                                        hashcpy(a.sha1, ren1->pair->two->sha1);
 987                                        a.mode = ren1->pair->two->mode;
 988                                        hashcpy(b.sha1, dst_other.sha1);
 989                                        b.mode = dst_other.mode;
 990                                        mfi = merge_file(o, &one, &a, &b,
 991                                                         branch1,
 992                                                         branch2);
 993                                        output(o, 1, "Adding merged %s", ren1_dst);
 994                                        update_file(o, 0,
 995                                                    mfi.sha,
 996                                                    mfi.mode,
 997                                                    ren1_dst);
 998                                } else {
 999                                        new_path = unique_path(o, ren1_dst, branch2);
1000                                        output(o, 1, "Adding as %s instead", new_path);
1001                                        update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
1002                                }
1003                        } else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
1004                                ren2 = item->util;
1005                                clean_merge = 0;
1006                                ren2->processed = 1;
1007                                output(o, 1, "CONFLICT (rename/rename): "
1008                                       "Rename %s->%s in %s. "
1009                                       "Rename %s->%s in %s",
1010                                       ren1_src, ren1_dst, branch1,
1011                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
1012                                conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1013                        } else
1014                                try_merge = 1;
1015
1016                        if (try_merge) {
1017                                struct diff_filespec *one, *a, *b;
1018                                struct merge_file_info mfi;
1019                                src_other.path = (char *)ren1_src;
1020
1021                                one = ren1->pair->one;
1022                                if (a_renames == renames1) {
1023                                        a = ren1->pair->two;
1024                                        b = &src_other;
1025                                } else {
1026                                        b = ren1->pair->two;
1027                                        a = &src_other;
1028                                }
1029                                mfi = merge_file(o, one, a, b,
1030                                                o->branch1, o->branch2);
1031
1032                                if (mfi.clean &&
1033                                    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1034                                    mfi.mode == ren1->pair->two->mode)
1035                                        /*
1036                                         * This messaged is part of
1037                                         * t6022 test. If you change
1038                                         * it update the test too.
1039                                         */
1040                                        output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1041                                else {
1042                                        if (mfi.merge || !mfi.clean)
1043                                                output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1044                                        if (mfi.merge)
1045                                                output(o, 2, "Auto-merging %s", ren1_dst);
1046                                        if (!mfi.clean) {
1047                                                output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1048                                                       ren1_dst);
1049                                                clean_merge = 0;
1050
1051                                                if (!o->call_depth)
1052                                                        update_stages(ren1_dst,
1053                                                                      one, a, b, 1);
1054                                        }
1055                                        update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1056                                }
1057                        }
1058                }
1059        }
1060        string_list_clear(&a_by_dst, 0);
1061        string_list_clear(&b_by_dst, 0);
1062
1063        return clean_merge;
1064}
1065
1066static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1067{
1068        return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1069}
1070
1071/* Per entry merge function */
1072static int process_entry(struct merge_options *o,
1073                         const char *path, struct stage_data *entry)
1074{
1075        /*
1076        printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1077        print_index_entry("\tpath: ", entry);
1078        */
1079        int clean_merge = 1;
1080        unsigned o_mode = entry->stages[1].mode;
1081        unsigned a_mode = entry->stages[2].mode;
1082        unsigned b_mode = entry->stages[3].mode;
1083        unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1084        unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1085        unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1086
1087        if (o_sha && (!a_sha || !b_sha)) {
1088                /* Case A: Deleted in one */
1089                if ((!a_sha && !b_sha) ||
1090                    (sha_eq(a_sha, o_sha) && !b_sha) ||
1091                    (!a_sha && sha_eq(b_sha, o_sha))) {
1092                        /* Deleted in both or deleted in one and
1093                         * unchanged in the other */
1094                        if (a_sha)
1095                                output(o, 2, "Removing %s", path);
1096                        /* do not touch working file if it did not exist */
1097                        remove_file(o, 1, path, !a_sha);
1098                } else {
1099                        /* Deleted in one and changed in the other */
1100                        clean_merge = 0;
1101                        if (!a_sha) {
1102                                output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1103                                       "and modified in %s. Version %s of %s left in tree.",
1104                                       path, o->branch1,
1105                                       o->branch2, o->branch2, path);
1106                                update_file(o, 0, b_sha, b_mode, path);
1107                        } else {
1108                                output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1109                                       "and modified in %s. Version %s of %s left in tree.",
1110                                       path, o->branch2,
1111                                       o->branch1, o->branch1, path);
1112                                update_file(o, 0, a_sha, a_mode, path);
1113                        }
1114                }
1115
1116        } else if ((!o_sha && a_sha && !b_sha) ||
1117                   (!o_sha && !a_sha && b_sha)) {
1118                /* Case B: Added in one. */
1119                const char *add_branch;
1120                const char *other_branch;
1121                unsigned mode;
1122                const unsigned char *sha;
1123                const char *conf;
1124
1125                if (a_sha) {
1126                        add_branch = o->branch1;
1127                        other_branch = o->branch2;
1128                        mode = a_mode;
1129                        sha = a_sha;
1130                        conf = "file/directory";
1131                } else {
1132                        add_branch = o->branch2;
1133                        other_branch = o->branch1;
1134                        mode = b_mode;
1135                        sha = b_sha;
1136                        conf = "directory/file";
1137                }
1138                if (string_list_has_string(&o->current_directory_set, path)) {
1139                        const char *new_path = unique_path(o, path, add_branch);
1140                        clean_merge = 0;
1141                        output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1142                               "Adding %s as %s",
1143                               conf, path, other_branch, path, new_path);
1144                        remove_file(o, 0, path, 0);
1145                        update_file(o, 0, sha, mode, new_path);
1146                } else {
1147                        output(o, 2, "Adding %s", path);
1148                        update_file(o, 1, sha, mode, path);
1149                }
1150        } else if (a_sha && b_sha) {
1151                /* Case C: Added in both (check for same permissions) and */
1152                /* case D: Modified in both, but differently. */
1153                const char *reason = "content";
1154                struct merge_file_info mfi;
1155                struct diff_filespec one, a, b;
1156
1157                if (!o_sha) {
1158                        reason = "add/add";
1159                        o_sha = (unsigned char *)null_sha1;
1160                }
1161                output(o, 2, "Auto-merging %s", path);
1162                one.path = a.path = b.path = (char *)path;
1163                hashcpy(one.sha1, o_sha);
1164                one.mode = o_mode;
1165                hashcpy(a.sha1, a_sha);
1166                a.mode = a_mode;
1167                hashcpy(b.sha1, b_sha);
1168                b.mode = b_mode;
1169
1170                mfi = merge_file(o, &one, &a, &b,
1171                                 o->branch1, o->branch2);
1172
1173                clean_merge = mfi.clean;
1174                if (!mfi.clean) {
1175                        if (S_ISGITLINK(mfi.mode))
1176                                reason = "submodule";
1177                        output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1178                                        reason, path);
1179                }
1180                update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1181        } else if (!o_sha && !a_sha && !b_sha) {
1182                /*
1183                 * this entry was deleted altogether. a_mode == 0 means
1184                 * we had that path and want to actively remove it.
1185                 */
1186                remove_file(o, 1, path, !a_mode);
1187        } else
1188                die("Fatal merge failure, shouldn't happen.");
1189
1190        return clean_merge;
1191}
1192
1193struct unpack_trees_error_msgs get_porcelain_error_msgs(void)
1194{
1195        struct unpack_trees_error_msgs msgs = {
1196                /* would_overwrite */
1197                "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1198                /* not_uptodate_file */
1199                "Your local changes to '%s' would be overwritten by merge.  Aborting.",
1200                /* not_uptodate_dir */
1201                "Updating '%s' would lose untracked files in it.  Aborting.",
1202                /* would_lose_untracked */
1203                "Untracked working tree file '%s' would be %s by merge.  Aborting",
1204                /* bind_overlap -- will not happen here */
1205                NULL,
1206        };
1207        if (advice_commit_before_merge) {
1208                msgs.would_overwrite = msgs.not_uptodate_file =
1209                        "Your local changes to '%s' would be overwritten by merge.  Aborting.\n"
1210                        "Please, commit your changes or stash them before you can merge.";
1211        }
1212        return msgs;
1213}
1214
1215int merge_trees(struct merge_options *o,
1216                struct tree *head,
1217                struct tree *merge,
1218                struct tree *common,
1219                struct tree **result)
1220{
1221        int code, clean;
1222
1223        if (o->subtree_shift) {
1224                merge = shift_tree_object(head, merge, o->subtree_shift);
1225                common = shift_tree_object(head, common, o->subtree_shift);
1226        }
1227
1228        if (sha_eq(common->object.sha1, merge->object.sha1)) {
1229                output(o, 0, "Already uptodate!");
1230                *result = head;
1231                return 1;
1232        }
1233
1234        code = git_merge_trees(o->call_depth, common, head, merge);
1235
1236        if (code != 0) {
1237                if (show(o, 4) || o->call_depth)
1238                        die("merging of trees %s and %s failed",
1239                            sha1_to_hex(head->object.sha1),
1240                            sha1_to_hex(merge->object.sha1));
1241                else
1242                        exit(128);
1243        }
1244
1245        if (unmerged_cache()) {
1246                struct string_list *entries, *re_head, *re_merge;
1247                int i;
1248                string_list_clear(&o->current_file_set, 1);
1249                string_list_clear(&o->current_directory_set, 1);
1250                get_files_dirs(o, head);
1251                get_files_dirs(o, merge);
1252
1253                entries = get_unmerged();
1254                re_head  = get_renames(o, head, common, head, merge, entries);
1255                re_merge = get_renames(o, merge, common, head, merge, entries);
1256                clean = process_renames(o, re_head, re_merge);
1257                for (i = 0; i < entries->nr; i++) {
1258                        const char *path = entries->items[i].string;
1259                        struct stage_data *e = entries->items[i].util;
1260                        if (!e->processed
1261                                && !process_entry(o, path, e))
1262                                clean = 0;
1263                }
1264
1265                string_list_clear(re_merge, 0);
1266                string_list_clear(re_head, 0);
1267                string_list_clear(entries, 1);
1268
1269        }
1270        else
1271                clean = 1;
1272
1273        if (o->call_depth)
1274                *result = write_tree_from_memory(o);
1275
1276        return clean;
1277}
1278
1279static struct commit_list *reverse_commit_list(struct commit_list *list)
1280{
1281        struct commit_list *next = NULL, *current, *backup;
1282        for (current = list; current; current = backup) {
1283                backup = current->next;
1284                current->next = next;
1285                next = current;
1286        }
1287        return next;
1288}
1289
1290/*
1291 * Merge the commits h1 and h2, return the resulting virtual
1292 * commit object and a flag indicating the cleanness of the merge.
1293 */
1294int merge_recursive(struct merge_options *o,
1295                    struct commit *h1,
1296                    struct commit *h2,
1297                    struct commit_list *ca,
1298                    struct commit **result)
1299{
1300        struct commit_list *iter;
1301        struct commit *merged_common_ancestors;
1302        struct tree *mrtree = mrtree;
1303        int clean;
1304
1305        if (show(o, 4)) {
1306                output(o, 4, "Merging:");
1307                output_commit_title(o, h1);
1308                output_commit_title(o, h2);
1309        }
1310
1311        if (!ca) {
1312                ca = get_merge_bases(h1, h2, 1);
1313                ca = reverse_commit_list(ca);
1314        }
1315
1316        if (show(o, 5)) {
1317                output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1318                for (iter = ca; iter; iter = iter->next)
1319                        output_commit_title(o, iter->item);
1320        }
1321
1322        merged_common_ancestors = pop_commit(&ca);
1323        if (merged_common_ancestors == NULL) {
1324                /* if there is no common ancestor, make an empty tree */
1325                struct tree *tree = xcalloc(1, sizeof(struct tree));
1326
1327                tree->object.parsed = 1;
1328                tree->object.type = OBJ_TREE;
1329                pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1330                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1331        }
1332
1333        for (iter = ca; iter; iter = iter->next) {
1334                const char *saved_b1, *saved_b2;
1335                o->call_depth++;
1336                /*
1337                 * When the merge fails, the result contains files
1338                 * with conflict markers. The cleanness flag is
1339                 * ignored, it was never actually used, as result of
1340                 * merge_trees has always overwritten it: the committed
1341                 * "conflicts" were already resolved.
1342                 */
1343                discard_cache();
1344                saved_b1 = o->branch1;
1345                saved_b2 = o->branch2;
1346                o->branch1 = "Temporary merge branch 1";
1347                o->branch2 = "Temporary merge branch 2";
1348                merge_recursive(o, merged_common_ancestors, iter->item,
1349                                NULL, &merged_common_ancestors);
1350                o->branch1 = saved_b1;
1351                o->branch2 = saved_b2;
1352                o->call_depth--;
1353
1354                if (!merged_common_ancestors)
1355                        die("merge returned no commit");
1356        }
1357
1358        discard_cache();
1359        if (!o->call_depth)
1360                read_cache();
1361
1362        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1363                            &mrtree);
1364
1365        if (o->call_depth) {
1366                *result = make_virtual_commit(mrtree, "merged tree");
1367                commit_list_insert(h1, &(*result)->parents);
1368                commit_list_insert(h2, &(*result)->parents->next);
1369        }
1370        flush_output(o);
1371        return clean;
1372}
1373
1374static struct commit *get_ref(const unsigned char *sha1, const char *name)
1375{
1376        struct object *object;
1377
1378        object = deref_tag(parse_object(sha1), name, strlen(name));
1379        if (!object)
1380                return NULL;
1381        if (object->type == OBJ_TREE)
1382                return make_virtual_commit((struct tree*)object, name);
1383        if (object->type != OBJ_COMMIT)
1384                return NULL;
1385        if (parse_commit((struct commit *)object))
1386                return NULL;
1387        return (struct commit *)object;
1388}
1389
1390int merge_recursive_generic(struct merge_options *o,
1391                            const unsigned char *head,
1392                            const unsigned char *merge,
1393                            int num_base_list,
1394                            const unsigned char **base_list,
1395                            struct commit **result)
1396{
1397        int clean, index_fd;
1398        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1399        struct commit *head_commit = get_ref(head, o->branch1);
1400        struct commit *next_commit = get_ref(merge, o->branch2);
1401        struct commit_list *ca = NULL;
1402
1403        if (base_list) {
1404                int i;
1405                for (i = 0; i < num_base_list; ++i) {
1406                        struct commit *base;
1407                        if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1408                                return error("Could not parse object '%s'",
1409                                        sha1_to_hex(base_list[i]));
1410                        commit_list_insert(base, &ca);
1411                }
1412        }
1413
1414        index_fd = hold_locked_index(lock, 1);
1415        clean = merge_recursive(o, head_commit, next_commit, ca,
1416                        result);
1417        if (active_cache_changed &&
1418                        (write_cache(index_fd, active_cache, active_nr) ||
1419                         commit_locked_index(lock)))
1420                return error("Unable to write index.");
1421
1422        return clean ? 0 : 1;
1423}
1424
1425static int merge_recursive_config(const char *var, const char *value, void *cb)
1426{
1427        struct merge_options *o = cb;
1428        if (!strcasecmp(var, "merge.verbosity")) {
1429                o->verbosity = git_config_int(var, value);
1430                return 0;
1431        }
1432        if (!strcasecmp(var, "diff.renamelimit")) {
1433                o->diff_rename_limit = git_config_int(var, value);
1434                return 0;
1435        }
1436        if (!strcasecmp(var, "merge.renamelimit")) {
1437                o->merge_rename_limit = git_config_int(var, value);
1438                return 0;
1439        }
1440        return git_xmerge_config(var, value, cb);
1441}
1442
1443void init_merge_options(struct merge_options *o)
1444{
1445        memset(o, 0, sizeof(struct merge_options));
1446        o->verbosity = 2;
1447        o->buffer_output = 1;
1448        o->diff_rename_limit = -1;
1449        o->merge_rename_limit = -1;
1450        git_config(merge_recursive_config, o);
1451        if (getenv("GIT_MERGE_VERBOSITY"))
1452                o->verbosity =
1453                        strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1454        if (o->verbosity >= 5)
1455                o->buffer_output = 0;
1456        strbuf_init(&o->obuf, 0);
1457        memset(&o->current_file_set, 0, sizeof(struct string_list));
1458        o->current_file_set.strdup_strings = 1;
1459        memset(&o->current_directory_set, 0, sizeof(struct string_list));
1460        o->current_directory_set.strdup_strings = 1;
1461}