merge-recursive.con commit Merge branch 'jn/maint-fast-import-object-reuse' into maint (267684f)
   1/*
   2 * Recursive Merge algorithm stolen from git-merge-recursive.py by
   3 * Fredrik Kuivinen.
   4 * The thieves were Alex Riesen and Johannes Schindelin, in June/July 2006
   5 */
   6#include "advice.h"
   7#include "cache.h"
   8#include "cache-tree.h"
   9#include "commit.h"
  10#include "blob.h"
  11#include "builtin.h"
  12#include "tree-walk.h"
  13#include "diff.h"
  14#include "diffcore.h"
  15#include "tag.h"
  16#include "unpack-trees.h"
  17#include "string-list.h"
  18#include "xdiff-interface.h"
  19#include "ll-merge.h"
  20#include "attr.h"
  21#include "merge-recursive.h"
  22#include "dir.h"
  23#include "submodule.h"
  24
  25static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  26                                      const char *subtree_shift)
  27{
  28        unsigned char shifted[20];
  29
  30        if (!*subtree_shift) {
  31                shift_tree(one->object.sha1, two->object.sha1, shifted, 0);
  32        } else {
  33                shift_tree_by(one->object.sha1, two->object.sha1, shifted,
  34                              subtree_shift);
  35        }
  36        if (!hashcmp(two->object.sha1, shifted))
  37                return two;
  38        return lookup_tree(shifted);
  39}
  40
  41/*
  42 * A virtual commit has (const char *)commit->util set to the name.
  43 */
  44
  45static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  46{
  47        struct commit *commit = xcalloc(1, sizeof(struct commit));
  48        commit->tree = tree;
  49        commit->util = (void*)comment;
  50        /* avoid warnings */
  51        commit->object.parsed = 1;
  52        return commit;
  53}
  54
  55/*
  56 * Since we use get_tree_entry(), which does not put the read object into
  57 * the object pool, we cannot rely on a == b.
  58 */
  59static int sha_eq(const unsigned char *a, const unsigned char *b)
  60{
  61        if (!a && !b)
  62                return 2;
  63        return a && b && hashcmp(a, b) == 0;
  64}
  65
  66/*
  67 * Since we want to write the index eventually, we cannot reuse the index
  68 * for these (temporary) data.
  69 */
  70struct stage_data
  71{
  72        struct
  73        {
  74                unsigned mode;
  75                unsigned char sha[20];
  76        } stages[4];
  77        unsigned processed:1;
  78};
  79
  80static int show(struct merge_options *o, int v)
  81{
  82        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
  83}
  84
  85static void flush_output(struct merge_options *o)
  86{
  87        if (o->obuf.len) {
  88                fputs(o->obuf.buf, stdout);
  89                strbuf_reset(&o->obuf);
  90        }
  91}
  92
  93__attribute__((format (printf, 3, 4)))
  94static void output(struct merge_options *o, int v, const char *fmt, ...)
  95{
  96        int len;
  97        va_list ap;
  98
  99        if (!show(o, v))
 100                return;
 101
 102        strbuf_grow(&o->obuf, o->call_depth * 2 + 2);
 103        memset(o->obuf.buf + o->obuf.len, ' ', o->call_depth * 2);
 104        strbuf_setlen(&o->obuf, o->obuf.len + o->call_depth * 2);
 105
 106        va_start(ap, fmt);
 107        len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 108        va_end(ap);
 109
 110        if (len < 0)
 111                len = 0;
 112        if (len >= strbuf_avail(&o->obuf)) {
 113                strbuf_grow(&o->obuf, len + 2);
 114                va_start(ap, fmt);
 115                len = vsnprintf(o->obuf.buf + o->obuf.len, strbuf_avail(&o->obuf), fmt, ap);
 116                va_end(ap);
 117                if (len >= strbuf_avail(&o->obuf)) {
 118                        die("this should not happen, your snprintf is broken");
 119                }
 120        }
 121        strbuf_setlen(&o->obuf, o->obuf.len + len);
 122        strbuf_add(&o->obuf, "\n", 1);
 123        if (!o->buffer_output)
 124                flush_output(o);
 125}
 126
 127static void output_commit_title(struct merge_options *o, struct commit *commit)
 128{
 129        int i;
 130        flush_output(o);
 131        for (i = o->call_depth; i--;)
 132                fputs("  ", stdout);
 133        if (commit->util)
 134                printf("virtual %s\n", (char *)commit->util);
 135        else {
 136                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 137                if (parse_commit(commit) != 0)
 138                        printf("(bad commit)\n");
 139                else {
 140                        const char *title;
 141                        int len = find_commit_subject(commit->buffer, &title);
 142                        if (len)
 143                                printf("%.*s\n", len, title);
 144                }
 145        }
 146}
 147
 148static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 149                const char *path, int stage, int refresh, int options)
 150{
 151        struct cache_entry *ce;
 152        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 153        if (!ce)
 154                return error("addinfo_cache failed for path '%s'", path);
 155        return add_cache_entry(ce, options);
 156}
 157
 158static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 159{
 160        parse_tree(tree);
 161        init_tree_desc(desc, tree->buffer, tree->size);
 162}
 163
 164static int git_merge_trees(int index_only,
 165                           struct tree *common,
 166                           struct tree *head,
 167                           struct tree *merge)
 168{
 169        int rc;
 170        struct tree_desc t[3];
 171        struct unpack_trees_options opts;
 172
 173        memset(&opts, 0, sizeof(opts));
 174        if (index_only)
 175                opts.index_only = 1;
 176        else
 177                opts.update = 1;
 178        opts.merge = 1;
 179        opts.head_idx = 2;
 180        opts.fn = threeway_merge;
 181        opts.src_index = &the_index;
 182        opts.dst_index = &the_index;
 183        setup_unpack_trees_porcelain(&opts, "merge");
 184
 185        init_tree_desc_from_tree(t+0, common);
 186        init_tree_desc_from_tree(t+1, head);
 187        init_tree_desc_from_tree(t+2, merge);
 188
 189        rc = unpack_trees(3, t, &opts);
 190        cache_tree_free(&active_cache_tree);
 191        return rc;
 192}
 193
 194struct tree *write_tree_from_memory(struct merge_options *o)
 195{
 196        struct tree *result = NULL;
 197
 198        if (unmerged_cache()) {
 199                int i;
 200                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 201                for (i = 0; i < active_nr; i++) {
 202                        struct cache_entry *ce = active_cache[i];
 203                        if (ce_stage(ce))
 204                                fprintf(stderr, "BUG: %d %.*s", ce_stage(ce),
 205                                        (int)ce_namelen(ce), ce->name);
 206                }
 207                die("Bug in merge-recursive.c");
 208        }
 209
 210        if (!active_cache_tree)
 211                active_cache_tree = cache_tree();
 212
 213        if (!cache_tree_fully_valid(active_cache_tree) &&
 214            cache_tree_update(active_cache_tree,
 215                              active_cache, active_nr, 0, 0) < 0)
 216                die("error building trees");
 217
 218        result = lookup_tree(active_cache_tree->sha1);
 219
 220        return result;
 221}
 222
 223static int save_files_dirs(const unsigned char *sha1,
 224                const char *base, int baselen, const char *path,
 225                unsigned int mode, int stage, void *context)
 226{
 227        int len = strlen(path);
 228        char *newpath = xmalloc(baselen + len + 1);
 229        struct merge_options *o = context;
 230
 231        memcpy(newpath, base, baselen);
 232        memcpy(newpath + baselen, path, len);
 233        newpath[baselen + len] = '\0';
 234
 235        if (S_ISDIR(mode))
 236                string_list_insert(&o->current_directory_set, newpath);
 237        else
 238                string_list_insert(&o->current_file_set, newpath);
 239        free(newpath);
 240
 241        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 242}
 243
 244static int get_files_dirs(struct merge_options *o, struct tree *tree)
 245{
 246        int n;
 247        if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs, o))
 248                return 0;
 249        n = o->current_file_set.nr + o->current_directory_set.nr;
 250        return n;
 251}
 252
 253/*
 254 * Returns an index_entry instance which doesn't have to correspond to
 255 * a real cache entry in Git's index.
 256 */
 257static struct stage_data *insert_stage_data(const char *path,
 258                struct tree *o, struct tree *a, struct tree *b,
 259                struct string_list *entries)
 260{
 261        struct string_list_item *item;
 262        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 263        get_tree_entry(o->object.sha1, path,
 264                        e->stages[1].sha, &e->stages[1].mode);
 265        get_tree_entry(a->object.sha1, path,
 266                        e->stages[2].sha, &e->stages[2].mode);
 267        get_tree_entry(b->object.sha1, path,
 268                        e->stages[3].sha, &e->stages[3].mode);
 269        item = string_list_insert(entries, path);
 270        item->util = e;
 271        return e;
 272}
 273
 274/*
 275 * Create a dictionary mapping file names to stage_data objects. The
 276 * dictionary contains one entry for every path with a non-zero stage entry.
 277 */
 278static struct string_list *get_unmerged(void)
 279{
 280        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 281        int i;
 282
 283        unmerged->strdup_strings = 1;
 284
 285        for (i = 0; i < active_nr; i++) {
 286                struct string_list_item *item;
 287                struct stage_data *e;
 288                struct cache_entry *ce = active_cache[i];
 289                if (!ce_stage(ce))
 290                        continue;
 291
 292                item = string_list_lookup(unmerged, ce->name);
 293                if (!item) {
 294                        item = string_list_insert(unmerged, ce->name);
 295                        item->util = xcalloc(1, sizeof(struct stage_data));
 296                }
 297                e = item->util;
 298                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 299                hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 300        }
 301
 302        return unmerged;
 303}
 304
 305struct rename
 306{
 307        struct diff_filepair *pair;
 308        struct stage_data *src_entry;
 309        struct stage_data *dst_entry;
 310        unsigned processed:1;
 311};
 312
 313/*
 314 * Get information of all renames which occurred between 'o_tree' and
 315 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 316 * 'b_tree') to be able to associate the correct cache entries with
 317 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 318 */
 319static struct string_list *get_renames(struct merge_options *o,
 320                                       struct tree *tree,
 321                                       struct tree *o_tree,
 322                                       struct tree *a_tree,
 323                                       struct tree *b_tree,
 324                                       struct string_list *entries)
 325{
 326        int i;
 327        struct string_list *renames;
 328        struct diff_options opts;
 329
 330        renames = xcalloc(1, sizeof(struct string_list));
 331        diff_setup(&opts);
 332        DIFF_OPT_SET(&opts, RECURSIVE);
 333        opts.detect_rename = DIFF_DETECT_RENAME;
 334        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 335                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 336                            500;
 337        opts.warn_on_too_large_rename = 1;
 338        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 339        if (diff_setup_done(&opts) < 0)
 340                die("diff setup failed");
 341        diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 342        diffcore_std(&opts);
 343        for (i = 0; i < diff_queued_diff.nr; ++i) {
 344                struct string_list_item *item;
 345                struct rename *re;
 346                struct diff_filepair *pair = diff_queued_diff.queue[i];
 347                if (pair->status != 'R') {
 348                        diff_free_filepair(pair);
 349                        continue;
 350                }
 351                re = xmalloc(sizeof(*re));
 352                re->processed = 0;
 353                re->pair = pair;
 354                item = string_list_lookup(entries, re->pair->one->path);
 355                if (!item)
 356                        re->src_entry = insert_stage_data(re->pair->one->path,
 357                                        o_tree, a_tree, b_tree, entries);
 358                else
 359                        re->src_entry = item->util;
 360
 361                item = string_list_lookup(entries, re->pair->two->path);
 362                if (!item)
 363                        re->dst_entry = insert_stage_data(re->pair->two->path,
 364                                        o_tree, a_tree, b_tree, entries);
 365                else
 366                        re->dst_entry = item->util;
 367                item = string_list_insert(renames, pair->one->path);
 368                item->util = re;
 369        }
 370        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 371        diff_queued_diff.nr = 0;
 372        diff_flush(&opts);
 373        return renames;
 374}
 375
 376static int update_stages(const char *path, struct diff_filespec *o,
 377                         struct diff_filespec *a, struct diff_filespec *b,
 378                         int clear)
 379{
 380        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 381        if (clear)
 382                if (remove_file_from_cache(path))
 383                        return -1;
 384        if (o)
 385                if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 386                        return -1;
 387        if (a)
 388                if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 389                        return -1;
 390        if (b)
 391                if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 392                        return -1;
 393        return 0;
 394}
 395
 396static int remove_file(struct merge_options *o, int clean,
 397                       const char *path, int no_wd)
 398{
 399        int update_cache = o->call_depth || clean;
 400        int update_working_directory = !o->call_depth && !no_wd;
 401
 402        if (update_cache) {
 403                if (remove_file_from_cache(path))
 404                        return -1;
 405        }
 406        if (update_working_directory) {
 407                if (remove_path(path))
 408                        return -1;
 409        }
 410        return 0;
 411}
 412
 413static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 414{
 415        char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 416        int suffix = 0;
 417        struct stat st;
 418        char *p = newpath + strlen(path);
 419        strcpy(newpath, path);
 420        *(p++) = '~';
 421        strcpy(p, branch);
 422        for (; *p; ++p)
 423                if ('/' == *p)
 424                        *p = '_';
 425        while (string_list_has_string(&o->current_file_set, newpath) ||
 426               string_list_has_string(&o->current_directory_set, newpath) ||
 427               lstat(newpath, &st) == 0)
 428                sprintf(p, "_%d", suffix++);
 429
 430        string_list_insert(&o->current_file_set, newpath);
 431        return newpath;
 432}
 433
 434static void flush_buffer(int fd, const char *buf, unsigned long size)
 435{
 436        while (size > 0) {
 437                long ret = write_in_full(fd, buf, size);
 438                if (ret < 0) {
 439                        /* Ignore epipe */
 440                        if (errno == EPIPE)
 441                                break;
 442                        die_errno("merge-recursive");
 443                } else if (!ret) {
 444                        die("merge-recursive: disk full?");
 445                }
 446                size -= ret;
 447                buf += ret;
 448        }
 449}
 450
 451static int would_lose_untracked(const char *path)
 452{
 453        int pos = cache_name_pos(path, strlen(path));
 454
 455        if (pos < 0)
 456                pos = -1 - pos;
 457        while (pos < active_nr &&
 458               !strcmp(path, active_cache[pos]->name)) {
 459                /*
 460                 * If stage #0, it is definitely tracked.
 461                 * If it has stage #2 then it was tracked
 462                 * before this merge started.  All other
 463                 * cases the path was not tracked.
 464                 */
 465                switch (ce_stage(active_cache[pos])) {
 466                case 0:
 467                case 2:
 468                        return 0;
 469                }
 470                pos++;
 471        }
 472        return file_exists(path);
 473}
 474
 475static int make_room_for_path(const char *path)
 476{
 477        int status;
 478        const char *msg = "failed to create path '%s'%s";
 479
 480        status = safe_create_leading_directories_const(path);
 481        if (status) {
 482                if (status == -3) {
 483                        /* something else exists */
 484                        error(msg, path, ": perhaps a D/F conflict?");
 485                        return -1;
 486                }
 487                die(msg, path, "");
 488        }
 489
 490        /*
 491         * Do not unlink a file in the work tree if we are not
 492         * tracking it.
 493         */
 494        if (would_lose_untracked(path))
 495                return error("refusing to lose untracked file at '%s'",
 496                             path);
 497
 498        /* Successful unlink is good.. */
 499        if (!unlink(path))
 500                return 0;
 501        /* .. and so is no existing file */
 502        if (errno == ENOENT)
 503                return 0;
 504        /* .. but not some other error (who really cares what?) */
 505        return error(msg, path, ": perhaps a D/F conflict?");
 506}
 507
 508static void update_file_flags(struct merge_options *o,
 509                              const unsigned char *sha,
 510                              unsigned mode,
 511                              const char *path,
 512                              int update_cache,
 513                              int update_wd)
 514{
 515        if (o->call_depth)
 516                update_wd = 0;
 517
 518        if (update_wd) {
 519                enum object_type type;
 520                void *buf;
 521                unsigned long size;
 522
 523                if (S_ISGITLINK(mode)) {
 524                        /*
 525                         * We may later decide to recursively descend into
 526                         * the submodule directory and update its index
 527                         * and/or work tree, but we do not do that now.
 528                         */
 529                        update_wd = 0;
 530                        goto update_index;
 531                }
 532
 533                buf = read_sha1_file(sha, &type, &size);
 534                if (!buf)
 535                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 536                if (type != OBJ_BLOB)
 537                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 538                if (S_ISREG(mode)) {
 539                        struct strbuf strbuf = STRBUF_INIT;
 540                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 541                                free(buf);
 542                                size = strbuf.len;
 543                                buf = strbuf_detach(&strbuf, NULL);
 544                        }
 545                }
 546
 547                if (make_room_for_path(path) < 0) {
 548                        update_wd = 0;
 549                        free(buf);
 550                        goto update_index;
 551                }
 552                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 553                        int fd;
 554                        if (mode & 0100)
 555                                mode = 0777;
 556                        else
 557                                mode = 0666;
 558                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 559                        if (fd < 0)
 560                                die_errno("failed to open '%s'", path);
 561                        flush_buffer(fd, buf, size);
 562                        close(fd);
 563                } else if (S_ISLNK(mode)) {
 564                        char *lnk = xmemdupz(buf, size);
 565                        safe_create_leading_directories_const(path);
 566                        unlink(path);
 567                        if (symlink(lnk, path))
 568                                die_errno("failed to symlink '%s'", path);
 569                        free(lnk);
 570                } else
 571                        die("do not know what to do with %06o %s '%s'",
 572                            mode, sha1_to_hex(sha), path);
 573                free(buf);
 574        }
 575 update_index:
 576        if (update_cache)
 577                add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 578}
 579
 580static void update_file(struct merge_options *o,
 581                        int clean,
 582                        const unsigned char *sha,
 583                        unsigned mode,
 584                        const char *path)
 585{
 586        update_file_flags(o, sha, mode, path, o->call_depth || clean, !o->call_depth);
 587}
 588
 589/* Low level file merging, update and removal */
 590
 591struct merge_file_info
 592{
 593        unsigned char sha[20];
 594        unsigned mode;
 595        unsigned clean:1,
 596                 merge:1;
 597};
 598
 599static int merge_3way(struct merge_options *o,
 600                      mmbuffer_t *result_buf,
 601                      struct diff_filespec *one,
 602                      struct diff_filespec *a,
 603                      struct diff_filespec *b,
 604                      const char *branch1,
 605                      const char *branch2)
 606{
 607        mmfile_t orig, src1, src2;
 608        char *base_name, *name1, *name2;
 609        int merge_status;
 610        int favor;
 611
 612        if (o->call_depth)
 613                favor = 0;
 614        else {
 615                switch (o->recursive_variant) {
 616                case MERGE_RECURSIVE_OURS:
 617                        favor = XDL_MERGE_FAVOR_OURS;
 618                        break;
 619                case MERGE_RECURSIVE_THEIRS:
 620                        favor = XDL_MERGE_FAVOR_THEIRS;
 621                        break;
 622                default:
 623                        favor = 0;
 624                        break;
 625                }
 626        }
 627
 628        if (strcmp(a->path, b->path) ||
 629            (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 630                base_name = o->ancestor == NULL ? NULL :
 631                        xstrdup(mkpath("%s:%s", o->ancestor, one->path));
 632                name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 633                name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 634        } else {
 635                base_name = o->ancestor == NULL ? NULL :
 636                        xstrdup(mkpath("%s", o->ancestor));
 637                name1 = xstrdup(mkpath("%s", branch1));
 638                name2 = xstrdup(mkpath("%s", branch2));
 639        }
 640
 641        read_mmblob(&orig, one->sha1);
 642        read_mmblob(&src1, a->sha1);
 643        read_mmblob(&src2, b->sha1);
 644
 645        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 646                                &src1, name1, &src2, name2,
 647                                ((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
 648                                 (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
 649                                 create_ll_flag(favor)));
 650
 651        free(name1);
 652        free(name2);
 653        free(orig.ptr);
 654        free(src1.ptr);
 655        free(src2.ptr);
 656        return merge_status;
 657}
 658
 659static struct merge_file_info merge_file(struct merge_options *o,
 660                                         struct diff_filespec *one,
 661                                         struct diff_filespec *a,
 662                                         struct diff_filespec *b,
 663                                         const char *branch1,
 664                                         const char *branch2)
 665{
 666        struct merge_file_info result;
 667        result.merge = 0;
 668        result.clean = 1;
 669
 670        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 671                result.clean = 0;
 672                if (S_ISREG(a->mode)) {
 673                        result.mode = a->mode;
 674                        hashcpy(result.sha, a->sha1);
 675                } else {
 676                        result.mode = b->mode;
 677                        hashcpy(result.sha, b->sha1);
 678                }
 679        } else {
 680                if (!sha_eq(a->sha1, one->sha1) && !sha_eq(b->sha1, one->sha1))
 681                        result.merge = 1;
 682
 683                /*
 684                 * Merge modes
 685                 */
 686                if (a->mode == b->mode || a->mode == one->mode)
 687                        result.mode = b->mode;
 688                else {
 689                        result.mode = a->mode;
 690                        if (b->mode != one->mode) {
 691                                result.clean = 0;
 692                                result.merge = 1;
 693                        }
 694                }
 695
 696                if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, one->sha1))
 697                        hashcpy(result.sha, b->sha1);
 698                else if (sha_eq(b->sha1, one->sha1))
 699                        hashcpy(result.sha, a->sha1);
 700                else if (S_ISREG(a->mode)) {
 701                        mmbuffer_t result_buf;
 702                        int merge_status;
 703
 704                        merge_status = merge_3way(o, &result_buf, one, a, b,
 705                                                  branch1, branch2);
 706
 707                        if ((merge_status < 0) || !result_buf.ptr)
 708                                die("Failed to execute internal merge");
 709
 710                        if (write_sha1_file(result_buf.ptr, result_buf.size,
 711                                            blob_type, result.sha))
 712                                die("Unable to add %s to database",
 713                                    a->path);
 714
 715                        free(result_buf.ptr);
 716                        result.clean = (merge_status == 0);
 717                } else if (S_ISGITLINK(a->mode)) {
 718                        result.clean = merge_submodule(result.sha, one->path, one->sha1,
 719                                                       a->sha1, b->sha1);
 720                } else if (S_ISLNK(a->mode)) {
 721                        hashcpy(result.sha, a->sha1);
 722
 723                        if (!sha_eq(a->sha1, b->sha1))
 724                                result.clean = 0;
 725                } else {
 726                        die("unsupported object type in the tree");
 727                }
 728        }
 729
 730        return result;
 731}
 732
 733static void conflict_rename_rename(struct merge_options *o,
 734                                   struct rename *ren1,
 735                                   const char *branch1,
 736                                   struct rename *ren2,
 737                                   const char *branch2)
 738{
 739        char *del[2];
 740        int delp = 0;
 741        const char *ren1_dst = ren1->pair->two->path;
 742        const char *ren2_dst = ren2->pair->two->path;
 743        const char *dst_name1 = ren1_dst;
 744        const char *dst_name2 = ren2_dst;
 745        if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 746                dst_name1 = del[delp++] = unique_path(o, ren1_dst, branch1);
 747                output(o, 1, "%s is a directory in %s adding as %s instead",
 748                       ren1_dst, branch2, dst_name1);
 749                remove_file(o, 0, ren1_dst, 0);
 750        }
 751        if (string_list_has_string(&o->current_directory_set, ren2_dst)) {
 752                dst_name2 = del[delp++] = unique_path(o, ren2_dst, branch2);
 753                output(o, 1, "%s is a directory in %s adding as %s instead",
 754                       ren2_dst, branch1, dst_name2);
 755                remove_file(o, 0, ren2_dst, 0);
 756        }
 757        if (o->call_depth) {
 758                remove_file_from_cache(dst_name1);
 759                remove_file_from_cache(dst_name2);
 760                /*
 761                 * Uncomment to leave the conflicting names in the resulting tree
 762                 *
 763                 * update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 764                 * update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 765                 */
 766        } else {
 767                update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 768                update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 769        }
 770        while (delp--)
 771                free(del[delp]);
 772}
 773
 774static void conflict_rename_dir(struct merge_options *o,
 775                                struct rename *ren1,
 776                                const char *branch1)
 777{
 778        char *new_path = unique_path(o, ren1->pair->two->path, branch1);
 779        output(o, 1, "Renaming %s to %s instead", ren1->pair->one->path, new_path);
 780        remove_file(o, 0, ren1->pair->two->path, 0);
 781        update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 782        free(new_path);
 783}
 784
 785static void conflict_rename_rename_2(struct merge_options *o,
 786                                     struct rename *ren1,
 787                                     const char *branch1,
 788                                     struct rename *ren2,
 789                                     const char *branch2)
 790{
 791        char *new_path1 = unique_path(o, ren1->pair->two->path, branch1);
 792        char *new_path2 = unique_path(o, ren2->pair->two->path, branch2);
 793        output(o, 1, "Renaming %s to %s and %s to %s instead",
 794               ren1->pair->one->path, new_path1,
 795               ren2->pair->one->path, new_path2);
 796        remove_file(o, 0, ren1->pair->two->path, 0);
 797        update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 798        update_file(o, 0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 799        free(new_path2);
 800        free(new_path1);
 801}
 802
 803static int process_renames(struct merge_options *o,
 804                           struct string_list *a_renames,
 805                           struct string_list *b_renames)
 806{
 807        int clean_merge = 1, i, j;
 808        struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
 809        struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
 810        const struct rename *sre;
 811
 812        for (i = 0; i < a_renames->nr; i++) {
 813                sre = a_renames->items[i].util;
 814                string_list_insert(&a_by_dst, sre->pair->two->path)->util
 815                        = sre->dst_entry;
 816        }
 817        for (i = 0; i < b_renames->nr; i++) {
 818                sre = b_renames->items[i].util;
 819                string_list_insert(&b_by_dst, sre->pair->two->path)->util
 820                        = sre->dst_entry;
 821        }
 822
 823        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 824                char *src;
 825                struct string_list *renames1, *renames2Dst;
 826                struct rename *ren1 = NULL, *ren2 = NULL;
 827                const char *branch1, *branch2;
 828                const char *ren1_src, *ren1_dst;
 829
 830                if (i >= a_renames->nr) {
 831                        ren2 = b_renames->items[j++].util;
 832                } else if (j >= b_renames->nr) {
 833                        ren1 = a_renames->items[i++].util;
 834                } else {
 835                        int compare = strcmp(a_renames->items[i].string,
 836                                             b_renames->items[j].string);
 837                        if (compare <= 0)
 838                                ren1 = a_renames->items[i++].util;
 839                        if (compare >= 0)
 840                                ren2 = b_renames->items[j++].util;
 841                }
 842
 843                /* TODO: refactor, so that 1/2 are not needed */
 844                if (ren1) {
 845                        renames1 = a_renames;
 846                        renames2Dst = &b_by_dst;
 847                        branch1 = o->branch1;
 848                        branch2 = o->branch2;
 849                } else {
 850                        struct rename *tmp;
 851                        renames1 = b_renames;
 852                        renames2Dst = &a_by_dst;
 853                        branch1 = o->branch2;
 854                        branch2 = o->branch1;
 855                        tmp = ren2;
 856                        ren2 = ren1;
 857                        ren1 = tmp;
 858                }
 859                src = ren1->pair->one->path;
 860
 861                ren1->dst_entry->processed = 1;
 862                ren1->src_entry->processed = 1;
 863
 864                if (ren1->processed)
 865                        continue;
 866                ren1->processed = 1;
 867
 868                ren1_src = ren1->pair->one->path;
 869                ren1_dst = ren1->pair->two->path;
 870
 871                if (ren2) {
 872                        const char *ren2_src = ren2->pair->one->path;
 873                        const char *ren2_dst = ren2->pair->two->path;
 874                        /* Renamed in 1 and renamed in 2 */
 875                        if (strcmp(ren1_src, ren2_src) != 0)
 876                                die("ren1.src != ren2.src");
 877                        ren2->dst_entry->processed = 1;
 878                        ren2->processed = 1;
 879                        if (strcmp(ren1_dst, ren2_dst) != 0) {
 880                                clean_merge = 0;
 881                                output(o, 1, "CONFLICT (rename/rename): "
 882                                       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 883                                       "rename \"%s\"->\"%s\" in \"%s\"%s",
 884                                       src, ren1_dst, branch1,
 885                                       src, ren2_dst, branch2,
 886                                       o->call_depth ? " (left unresolved)": "");
 887                                if (o->call_depth) {
 888                                        remove_file_from_cache(src);
 889                                        update_file(o, 0, ren1->pair->one->sha1,
 890                                                    ren1->pair->one->mode, src);
 891                                }
 892                                conflict_rename_rename(o, ren1, branch1, ren2, branch2);
 893                        } else {
 894                                struct merge_file_info mfi;
 895                                remove_file(o, 1, ren1_src, 1);
 896                                mfi = merge_file(o,
 897                                                 ren1->pair->one,
 898                                                 ren1->pair->two,
 899                                                 ren2->pair->two,
 900                                                 branch1,
 901                                                 branch2);
 902                                if (mfi.merge || !mfi.clean)
 903                                        output(o, 1, "Renaming %s->%s", src, ren1_dst);
 904
 905                                if (mfi.merge)
 906                                        output(o, 2, "Auto-merging %s", ren1_dst);
 907
 908                                if (!mfi.clean) {
 909                                        output(o, 1, "CONFLICT (content): merge conflict in %s",
 910                                               ren1_dst);
 911                                        clean_merge = 0;
 912
 913                                        if (!o->call_depth)
 914                                                update_stages(ren1_dst,
 915                                                              ren1->pair->one,
 916                                                              ren1->pair->two,
 917                                                              ren2->pair->two,
 918                                                              1 /* clear */);
 919                                }
 920                                update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 921                        }
 922                } else {
 923                        /* Renamed in 1, maybe changed in 2 */
 924                        struct string_list_item *item;
 925                        /* we only use sha1 and mode of these */
 926                        struct diff_filespec src_other, dst_other;
 927                        int try_merge, stage = a_renames == renames1 ? 3: 2;
 928
 929                        remove_file(o, 1, ren1_src, o->call_depth || stage == 3);
 930
 931                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 932                        src_other.mode = ren1->src_entry->stages[stage].mode;
 933                        hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 934                        dst_other.mode = ren1->dst_entry->stages[stage].mode;
 935
 936                        try_merge = 0;
 937
 938                        if (string_list_has_string(&o->current_directory_set, ren1_dst)) {
 939                                clean_merge = 0;
 940                                output(o, 1, "CONFLICT (rename/directory): Rename %s->%s in %s "
 941                                       " directory %s added in %s",
 942                                       ren1_src, ren1_dst, branch1,
 943                                       ren1_dst, branch2);
 944                                conflict_rename_dir(o, ren1, branch1);
 945                        } else if (sha_eq(src_other.sha1, null_sha1)) {
 946                                clean_merge = 0;
 947                                output(o, 1, "CONFLICT (rename/delete): Rename %s->%s in %s "
 948                                       "and deleted in %s",
 949                                       ren1_src, ren1_dst, branch1,
 950                                       branch2);
 951                                update_file(o, 0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 952                                if (!o->call_depth)
 953                                        update_stages(ren1_dst, NULL,
 954                                                        branch1 == o->branch1 ?
 955                                                        ren1->pair->two : NULL,
 956                                                        branch1 == o->branch1 ?
 957                                                        NULL : ren1->pair->two, 1);
 958                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
 959                                   sha_eq(dst_other.sha1, ren1->pair->two->sha1)) {
 960                                /* Added file on the other side
 961                                   identical to the file being
 962                                   renamed: clean merge */
 963                                update_file(o, 1, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 964                        } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 965                                const char *new_path;
 966                                clean_merge = 0;
 967                                try_merge = 1;
 968                                output(o, 1, "CONFLICT (rename/add): Rename %s->%s in %s. "
 969                                       "%s added in %s",
 970                                       ren1_src, ren1_dst, branch1,
 971                                       ren1_dst, branch2);
 972                                if (o->call_depth) {
 973                                        struct merge_file_info mfi;
 974                                        struct diff_filespec one, a, b;
 975
 976                                        one.path = a.path = b.path =
 977                                                (char *)ren1_dst;
 978                                        hashcpy(one.sha1, null_sha1);
 979                                        one.mode = 0;
 980                                        hashcpy(a.sha1, ren1->pair->two->sha1);
 981                                        a.mode = ren1->pair->two->mode;
 982                                        hashcpy(b.sha1, dst_other.sha1);
 983                                        b.mode = dst_other.mode;
 984                                        mfi = merge_file(o, &one, &a, &b,
 985                                                         branch1,
 986                                                         branch2);
 987                                        output(o, 1, "Adding merged %s", ren1_dst);
 988                                        update_file(o, 0,
 989                                                    mfi.sha,
 990                                                    mfi.mode,
 991                                                    ren1_dst);
 992                                } else {
 993                                        new_path = unique_path(o, ren1_dst, branch2);
 994                                        output(o, 1, "Adding as %s instead", new_path);
 995                                        update_file(o, 0, dst_other.sha1, dst_other.mode, new_path);
 996                                }
 997                        } else if ((item = string_list_lookup(renames2Dst, ren1_dst))) {
 998                                ren2 = item->util;
 999                                clean_merge = 0;
1000                                ren2->processed = 1;
1001                                output(o, 1, "CONFLICT (rename/rename): "
1002                                       "Rename %s->%s in %s. "
1003                                       "Rename %s->%s in %s",
1004                                       ren1_src, ren1_dst, branch1,
1005                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
1006                                conflict_rename_rename_2(o, ren1, branch1, ren2, branch2);
1007                        } else
1008                                try_merge = 1;
1009
1010                        if (try_merge) {
1011                                struct diff_filespec *one, *a, *b;
1012                                struct merge_file_info mfi;
1013                                src_other.path = (char *)ren1_src;
1014
1015                                one = ren1->pair->one;
1016                                if (a_renames == renames1) {
1017                                        a = ren1->pair->two;
1018                                        b = &src_other;
1019                                } else {
1020                                        b = ren1->pair->two;
1021                                        a = &src_other;
1022                                }
1023                                mfi = merge_file(o, one, a, b,
1024                                                o->branch1, o->branch2);
1025
1026                                if (mfi.clean &&
1027                                    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
1028                                    mfi.mode == ren1->pair->two->mode) {
1029                                        /*
1030                                         * This message is part of
1031                                         * t6022 test. If you change
1032                                         * it update the test too.
1033                                         */
1034                                        output(o, 3, "Skipped %s (merged same as existing)", ren1_dst);
1035
1036                                        /* There may be higher stage entries left
1037                                         * in the index (e.g. due to a D/F
1038                                         * conflict) that need to be resolved.
1039                                         */
1040                                        if (!ren1->dst_entry->stages[2].mode !=
1041                                            !ren1->dst_entry->stages[3].mode)
1042                                                ren1->dst_entry->processed = 0;
1043                                } else {
1044                                        if (mfi.merge || !mfi.clean)
1045                                                output(o, 1, "Renaming %s => %s", ren1_src, ren1_dst);
1046                                        if (mfi.merge)
1047                                                output(o, 2, "Auto-merging %s", ren1_dst);
1048                                        if (!mfi.clean) {
1049                                                output(o, 1, "CONFLICT (rename/modify): Merge conflict in %s",
1050                                                       ren1_dst);
1051                                                clean_merge = 0;
1052
1053                                                if (!o->call_depth)
1054                                                        update_stages(ren1_dst,
1055                                                                      one, a, b, 1);
1056                                        }
1057                                        update_file(o, mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1058                                }
1059                        }
1060                }
1061        }
1062        string_list_clear(&a_by_dst, 0);
1063        string_list_clear(&b_by_dst, 0);
1064
1065        return clean_merge;
1066}
1067
1068static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1069{
1070        return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1071}
1072
1073static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
1074{
1075        void *buf;
1076        enum object_type type;
1077        unsigned long size;
1078        buf = read_sha1_file(sha1, &type, &size);
1079        if (!buf)
1080                return error("cannot read object %s", sha1_to_hex(sha1));
1081        if (type != OBJ_BLOB) {
1082                free(buf);
1083                return error("object %s is not a blob", sha1_to_hex(sha1));
1084        }
1085        strbuf_attach(dst, buf, size, size + 1);
1086        return 0;
1087}
1088
1089static int blob_unchanged(const unsigned char *o_sha,
1090                          const unsigned char *a_sha,
1091                          int renormalize, const char *path)
1092{
1093        struct strbuf o = STRBUF_INIT;
1094        struct strbuf a = STRBUF_INIT;
1095        int ret = 0; /* assume changed for safety */
1096
1097        if (sha_eq(o_sha, a_sha))
1098                return 1;
1099        if (!renormalize)
1100                return 0;
1101
1102        assert(o_sha && a_sha);
1103        if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
1104                goto error_return;
1105        /*
1106         * Note: binary | is used so that both renormalizations are
1107         * performed.  Comparison can be skipped if both files are
1108         * unchanged since their sha1s have already been compared.
1109         */
1110        if (renormalize_buffer(path, o.buf, o.len, &o) |
1111            renormalize_buffer(path, a.buf, o.len, &a))
1112                ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1113
1114error_return:
1115        strbuf_release(&o);
1116        strbuf_release(&a);
1117        return ret;
1118}
1119
1120/* Per entry merge function */
1121static int process_entry(struct merge_options *o,
1122                         const char *path, struct stage_data *entry)
1123{
1124        /*
1125        printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1126        print_index_entry("\tpath: ", entry);
1127        */
1128        int clean_merge = 1;
1129        int normalize = o->renormalize;
1130        unsigned o_mode = entry->stages[1].mode;
1131        unsigned a_mode = entry->stages[2].mode;
1132        unsigned b_mode = entry->stages[3].mode;
1133        unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1134        unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1135        unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1136
1137        entry->processed = 1;
1138        if (o_sha && (!a_sha || !b_sha)) {
1139                /* Case A: Deleted in one */
1140                if ((!a_sha && !b_sha) ||
1141                    (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
1142                    (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
1143                        /* Deleted in both or deleted in one and
1144                         * unchanged in the other */
1145                        if (a_sha)
1146                                output(o, 2, "Removing %s", path);
1147                        /* do not touch working file if it did not exist */
1148                        remove_file(o, 1, path, !a_sha);
1149                } else {
1150                        /* Deleted in one and changed in the other */
1151                        clean_merge = 0;
1152                        if (!a_sha) {
1153                                output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1154                                       "and modified in %s. Version %s of %s left in tree.",
1155                                       path, o->branch1,
1156                                       o->branch2, o->branch2, path);
1157                                update_file(o, 0, b_sha, b_mode, path);
1158                        } else {
1159                                output(o, 1, "CONFLICT (delete/modify): %s deleted in %s "
1160                                       "and modified in %s. Version %s of %s left in tree.",
1161                                       path, o->branch2,
1162                                       o->branch1, o->branch1, path);
1163                                update_file(o, 0, a_sha, a_mode, path);
1164                        }
1165                }
1166
1167        } else if ((!o_sha && a_sha && !b_sha) ||
1168                   (!o_sha && !a_sha && b_sha)) {
1169                /* Case B: Added in one. */
1170                unsigned mode;
1171                const unsigned char *sha;
1172
1173                if (a_sha) {
1174                        mode = a_mode;
1175                        sha = a_sha;
1176                } else {
1177                        mode = b_mode;
1178                        sha = b_sha;
1179                }
1180                if (string_list_has_string(&o->current_directory_set, path)) {
1181                        /* Handle D->F conflicts after all subfiles */
1182                        entry->processed = 0;
1183                        /* But get any file out of the way now, so conflicted
1184                         * entries below the directory of the same name can
1185                         * be put in the working directory.
1186                         */
1187                        if (a_sha)
1188                                output(o, 2, "Removing %s", path);
1189                        /* do not touch working file if it did not exist */
1190                        remove_file(o, 0, path, !a_sha);
1191                        return 1; /* Assume clean till processed */
1192                } else {
1193                        output(o, 2, "Adding %s", path);
1194                        update_file(o, 1, sha, mode, path);
1195                }
1196        } else if (a_sha && b_sha) {
1197                /* Case C: Added in both (check for same permissions) and */
1198                /* case D: Modified in both, but differently. */
1199                const char *reason = "content";
1200                struct merge_file_info mfi;
1201                struct diff_filespec one, a, b;
1202
1203                if (!o_sha) {
1204                        reason = "add/add";
1205                        o_sha = (unsigned char *)null_sha1;
1206                }
1207                output(o, 2, "Auto-merging %s", path);
1208                one.path = a.path = b.path = (char *)path;
1209                hashcpy(one.sha1, o_sha);
1210                one.mode = o_mode;
1211                hashcpy(a.sha1, a_sha);
1212                a.mode = a_mode;
1213                hashcpy(b.sha1, b_sha);
1214                b.mode = b_mode;
1215
1216                mfi = merge_file(o, &one, &a, &b,
1217                                 o->branch1, o->branch2);
1218
1219                clean_merge = mfi.clean;
1220                if (!mfi.clean) {
1221                        if (S_ISGITLINK(mfi.mode))
1222                                reason = "submodule";
1223                        output(o, 1, "CONFLICT (%s): Merge conflict in %s",
1224                                        reason, path);
1225                }
1226                update_file(o, mfi.clean, mfi.sha, mfi.mode, path);
1227        } else if (!o_sha && !a_sha && !b_sha) {
1228                /*
1229                 * this entry was deleted altogether. a_mode == 0 means
1230                 * we had that path and want to actively remove it.
1231                 */
1232                remove_file(o, 1, path, !a_mode);
1233        } else
1234                die("Fatal merge failure, shouldn't happen.");
1235
1236        return clean_merge;
1237}
1238
1239/*
1240 * Per entry merge function for D/F conflicts, to be called only after
1241 * all files below dir have been processed.  We do this because in the
1242 * cases we can cleanly resolve D/F conflicts, process_entry() can clean
1243 * out all the files below the directory for us.
1244 */
1245static int process_df_entry(struct merge_options *o,
1246                         const char *path, struct stage_data *entry)
1247{
1248        int clean_merge = 1;
1249        unsigned o_mode = entry->stages[1].mode;
1250        unsigned a_mode = entry->stages[2].mode;
1251        unsigned b_mode = entry->stages[3].mode;
1252        unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1253        unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1254        unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1255        const char *add_branch;
1256        const char *other_branch;
1257        unsigned mode;
1258        const unsigned char *sha;
1259        const char *conf;
1260        struct stat st;
1261
1262        /* We currently only handle D->F cases */
1263        assert((!o_sha && a_sha && !b_sha) ||
1264               (!o_sha && !a_sha && b_sha));
1265
1266        entry->processed = 1;
1267
1268        if (a_sha) {
1269                add_branch = o->branch1;
1270                other_branch = o->branch2;
1271                mode = a_mode;
1272                sha = a_sha;
1273                conf = "file/directory";
1274        } else {
1275                add_branch = o->branch2;
1276                other_branch = o->branch1;
1277                mode = b_mode;
1278                sha = b_sha;
1279                conf = "directory/file";
1280        }
1281        if (lstat(path, &st) == 0 && S_ISDIR(st.st_mode)) {
1282                const char *new_path = unique_path(o, path, add_branch);
1283                clean_merge = 0;
1284                output(o, 1, "CONFLICT (%s): There is a directory with name %s in %s. "
1285                       "Adding %s as %s",
1286                       conf, path, other_branch, path, new_path);
1287                remove_file(o, 0, path, 0);
1288                update_file(o, 0, sha, mode, new_path);
1289        } else {
1290                output(o, 2, "Adding %s", path);
1291                update_file(o, 1, sha, mode, path);
1292        }
1293
1294        return clean_merge;
1295}
1296
1297int merge_trees(struct merge_options *o,
1298                struct tree *head,
1299                struct tree *merge,
1300                struct tree *common,
1301                struct tree **result)
1302{
1303        int code, clean;
1304
1305        if (o->subtree_shift) {
1306                merge = shift_tree_object(head, merge, o->subtree_shift);
1307                common = shift_tree_object(head, common, o->subtree_shift);
1308        }
1309
1310        if (sha_eq(common->object.sha1, merge->object.sha1)) {
1311                output(o, 0, "Already up-to-date!");
1312                *result = head;
1313                return 1;
1314        }
1315
1316        code = git_merge_trees(o->call_depth, common, head, merge);
1317
1318        if (code != 0) {
1319                if (show(o, 4) || o->call_depth)
1320                        die("merging of trees %s and %s failed",
1321                            sha1_to_hex(head->object.sha1),
1322                            sha1_to_hex(merge->object.sha1));
1323                else
1324                        exit(128);
1325        }
1326
1327        if (unmerged_cache()) {
1328                struct string_list *entries, *re_head, *re_merge;
1329                int i;
1330                string_list_clear(&o->current_file_set, 1);
1331                string_list_clear(&o->current_directory_set, 1);
1332                get_files_dirs(o, head);
1333                get_files_dirs(o, merge);
1334
1335                entries = get_unmerged();
1336                re_head  = get_renames(o, head, common, head, merge, entries);
1337                re_merge = get_renames(o, merge, common, head, merge, entries);
1338                clean = process_renames(o, re_head, re_merge);
1339                for (i = 0; i < entries->nr; i++) {
1340                        const char *path = entries->items[i].string;
1341                        struct stage_data *e = entries->items[i].util;
1342                        if (!e->processed
1343                                && !process_entry(o, path, e))
1344                                clean = 0;
1345                }
1346                for (i = 0; i < entries->nr; i++) {
1347                        const char *path = entries->items[i].string;
1348                        struct stage_data *e = entries->items[i].util;
1349                        if (!e->processed
1350                                && !process_df_entry(o, path, e))
1351                                clean = 0;
1352                }
1353
1354                string_list_clear(re_merge, 0);
1355                string_list_clear(re_head, 0);
1356                string_list_clear(entries, 1);
1357
1358        }
1359        else
1360                clean = 1;
1361
1362        if (o->call_depth)
1363                *result = write_tree_from_memory(o);
1364
1365        return clean;
1366}
1367
1368static struct commit_list *reverse_commit_list(struct commit_list *list)
1369{
1370        struct commit_list *next = NULL, *current, *backup;
1371        for (current = list; current; current = backup) {
1372                backup = current->next;
1373                current->next = next;
1374                next = current;
1375        }
1376        return next;
1377}
1378
1379/*
1380 * Merge the commits h1 and h2, return the resulting virtual
1381 * commit object and a flag indicating the cleanness of the merge.
1382 */
1383int merge_recursive(struct merge_options *o,
1384                    struct commit *h1,
1385                    struct commit *h2,
1386                    struct commit_list *ca,
1387                    struct commit **result)
1388{
1389        struct commit_list *iter;
1390        struct commit *merged_common_ancestors;
1391        struct tree *mrtree = mrtree;
1392        int clean;
1393
1394        if (show(o, 4)) {
1395                output(o, 4, "Merging:");
1396                output_commit_title(o, h1);
1397                output_commit_title(o, h2);
1398        }
1399
1400        if (!ca) {
1401                ca = get_merge_bases(h1, h2, 1);
1402                ca = reverse_commit_list(ca);
1403        }
1404
1405        if (show(o, 5)) {
1406                output(o, 5, "found %u common ancestor(s):", commit_list_count(ca));
1407                for (iter = ca; iter; iter = iter->next)
1408                        output_commit_title(o, iter->item);
1409        }
1410
1411        merged_common_ancestors = pop_commit(&ca);
1412        if (merged_common_ancestors == NULL) {
1413                /* if there is no common ancestor, make an empty tree */
1414                struct tree *tree = xcalloc(1, sizeof(struct tree));
1415
1416                tree->object.parsed = 1;
1417                tree->object.type = OBJ_TREE;
1418                pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1419                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1420        }
1421
1422        for (iter = ca; iter; iter = iter->next) {
1423                const char *saved_b1, *saved_b2;
1424                o->call_depth++;
1425                /*
1426                 * When the merge fails, the result contains files
1427                 * with conflict markers. The cleanness flag is
1428                 * ignored, it was never actually used, as result of
1429                 * merge_trees has always overwritten it: the committed
1430                 * "conflicts" were already resolved.
1431                 */
1432                discard_cache();
1433                saved_b1 = o->branch1;
1434                saved_b2 = o->branch2;
1435                o->branch1 = "Temporary merge branch 1";
1436                o->branch2 = "Temporary merge branch 2";
1437                merge_recursive(o, merged_common_ancestors, iter->item,
1438                                NULL, &merged_common_ancestors);
1439                o->branch1 = saved_b1;
1440                o->branch2 = saved_b2;
1441                o->call_depth--;
1442
1443                if (!merged_common_ancestors)
1444                        die("merge returned no commit");
1445        }
1446
1447        discard_cache();
1448        if (!o->call_depth)
1449                read_cache();
1450
1451        o->ancestor = "merged common ancestors";
1452        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
1453                            &mrtree);
1454
1455        if (o->call_depth) {
1456                *result = make_virtual_commit(mrtree, "merged tree");
1457                commit_list_insert(h1, &(*result)->parents);
1458                commit_list_insert(h2, &(*result)->parents->next);
1459        }
1460        flush_output(o);
1461        return clean;
1462}
1463
1464static struct commit *get_ref(const unsigned char *sha1, const char *name)
1465{
1466        struct object *object;
1467
1468        object = deref_tag(parse_object(sha1), name, strlen(name));
1469        if (!object)
1470                return NULL;
1471        if (object->type == OBJ_TREE)
1472                return make_virtual_commit((struct tree*)object, name);
1473        if (object->type != OBJ_COMMIT)
1474                return NULL;
1475        if (parse_commit((struct commit *)object))
1476                return NULL;
1477        return (struct commit *)object;
1478}
1479
1480int merge_recursive_generic(struct merge_options *o,
1481                            const unsigned char *head,
1482                            const unsigned char *merge,
1483                            int num_base_list,
1484                            const unsigned char **base_list,
1485                            struct commit **result)
1486{
1487        int clean, index_fd;
1488        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1489        struct commit *head_commit = get_ref(head, o->branch1);
1490        struct commit *next_commit = get_ref(merge, o->branch2);
1491        struct commit_list *ca = NULL;
1492
1493        if (base_list) {
1494                int i;
1495                for (i = 0; i < num_base_list; ++i) {
1496                        struct commit *base;
1497                        if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
1498                                return error("Could not parse object '%s'",
1499                                        sha1_to_hex(base_list[i]));
1500                        commit_list_insert(base, &ca);
1501                }
1502        }
1503
1504        index_fd = hold_locked_index(lock, 1);
1505        clean = merge_recursive(o, head_commit, next_commit, ca,
1506                        result);
1507        if (active_cache_changed &&
1508                        (write_cache(index_fd, active_cache, active_nr) ||
1509                         commit_locked_index(lock)))
1510                return error("Unable to write index.");
1511
1512        return clean ? 0 : 1;
1513}
1514
1515static int merge_recursive_config(const char *var, const char *value, void *cb)
1516{
1517        struct merge_options *o = cb;
1518        if (!strcasecmp(var, "merge.verbosity")) {
1519                o->verbosity = git_config_int(var, value);
1520                return 0;
1521        }
1522        if (!strcasecmp(var, "diff.renamelimit")) {
1523                o->diff_rename_limit = git_config_int(var, value);
1524                return 0;
1525        }
1526        if (!strcasecmp(var, "merge.renamelimit")) {
1527                o->merge_rename_limit = git_config_int(var, value);
1528                return 0;
1529        }
1530        return git_xmerge_config(var, value, cb);
1531}
1532
1533void init_merge_options(struct merge_options *o)
1534{
1535        memset(o, 0, sizeof(struct merge_options));
1536        o->verbosity = 2;
1537        o->buffer_output = 1;
1538        o->diff_rename_limit = -1;
1539        o->merge_rename_limit = -1;
1540        o->renormalize = 0;
1541        git_config(merge_recursive_config, o);
1542        if (getenv("GIT_MERGE_VERBOSITY"))
1543                o->verbosity =
1544                        strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1545        if (o->verbosity >= 5)
1546                o->buffer_output = 0;
1547        strbuf_init(&o->obuf, 0);
1548        memset(&o->current_file_set, 0, sizeof(struct string_list));
1549        o->current_file_set.strdup_strings = 1;
1550        memset(&o->current_directory_set, 0, sizeof(struct string_list));
1551        o->current_directory_set.strdup_strings = 1;
1552}