builtin-merge-recursive.con commit Add shortcut in refresh_cache_ent() for marked entries. (aa9349d)
   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 "cache.h"
   7#include "cache-tree.h"
   8#include "commit.h"
   9#include "blob.h"
  10#include "builtin.h"
  11#include "tree-walk.h"
  12#include "diff.h"
  13#include "diffcore.h"
  14#include "tag.h"
  15#include "unpack-trees.h"
  16#include "path-list.h"
  17#include "xdiff-interface.h"
  18#include "ll-merge.h"
  19#include "interpolate.h"
  20#include "attr.h"
  21#include "merge-recursive.h"
  22
  23static int subtree_merge;
  24
  25static struct tree *shift_tree_object(struct tree *one, struct tree *two)
  26{
  27        unsigned char shifted[20];
  28
  29        /*
  30         * NEEDSWORK: this limits the recursion depth to hardcoded
  31         * value '2' to avoid excessive overhead.
  32         */
  33        shift_tree(one->object.sha1, two->object.sha1, shifted, 2);
  34        if (!hashcmp(two->object.sha1, shifted))
  35                return two;
  36        return lookup_tree(shifted);
  37}
  38
  39/*
  40 * A virtual commit has
  41 * - (const char *)commit->util set to the name, and
  42 * - *(int *)commit->object.sha1 set to the virtual id.
  43 */
  44
  45static unsigned commit_list_count(const struct commit_list *l)
  46{
  47        unsigned c = 0;
  48        for (; l; l = l->next )
  49                c++;
  50        return c;
  51}
  52
  53static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  54{
  55        struct commit *commit = xcalloc(1, sizeof(struct commit));
  56        static unsigned virtual_id = 1;
  57        commit->tree = tree;
  58        commit->util = (void*)comment;
  59        *(int*)commit->object.sha1 = virtual_id++;
  60        /* avoid warnings */
  61        commit->object.parsed = 1;
  62        return commit;
  63}
  64
  65/*
  66 * Since we use get_tree_entry(), which does not put the read object into
  67 * the object pool, we cannot rely on a == b.
  68 */
  69static int sha_eq(const unsigned char *a, const unsigned char *b)
  70{
  71        if (!a && !b)
  72                return 2;
  73        return a && b && hashcmp(a, b) == 0;
  74}
  75
  76/*
  77 * Since we want to write the index eventually, we cannot reuse the index
  78 * for these (temporary) data.
  79 */
  80struct stage_data
  81{
  82        struct
  83        {
  84                unsigned mode;
  85                unsigned char sha[20];
  86        } stages[4];
  87        unsigned processed:1;
  88};
  89
  90static struct path_list current_file_set = {NULL, 0, 0, 1};
  91static struct path_list current_directory_set = {NULL, 0, 0, 1};
  92
  93static int call_depth = 0;
  94static int verbosity = 2;
  95static int diff_rename_limit = -1;
  96static int merge_rename_limit = -1;
  97static int buffer_output = 1;
  98static struct strbuf obuf = STRBUF_INIT;
  99
 100static int show(int v)
 101{
 102        return (!call_depth && verbosity >= v) || verbosity >= 5;
 103}
 104
 105static void flush_output(void)
 106{
 107        if (obuf.len) {
 108                fputs(obuf.buf, stdout);
 109                strbuf_reset(&obuf);
 110        }
 111}
 112
 113static void output(int v, const char *fmt, ...)
 114{
 115        int len;
 116        va_list ap;
 117
 118        if (!show(v))
 119                return;
 120
 121        strbuf_grow(&obuf, call_depth * 2 + 2);
 122        memset(obuf.buf + obuf.len, ' ', call_depth * 2);
 123        strbuf_setlen(&obuf, obuf.len + call_depth * 2);
 124
 125        va_start(ap, fmt);
 126        len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 127        va_end(ap);
 128
 129        if (len < 0)
 130                len = 0;
 131        if (len >= strbuf_avail(&obuf)) {
 132                strbuf_grow(&obuf, len + 2);
 133                va_start(ap, fmt);
 134                len = vsnprintf(obuf.buf + obuf.len, strbuf_avail(&obuf), fmt, ap);
 135                va_end(ap);
 136                if (len >= strbuf_avail(&obuf)) {
 137                        die("this should not happen, your snprintf is broken");
 138                }
 139        }
 140        strbuf_setlen(&obuf, obuf.len + len);
 141        strbuf_add(&obuf, "\n", 1);
 142        if (!buffer_output)
 143                flush_output();
 144}
 145
 146static void output_commit_title(struct commit *commit)
 147{
 148        int i;
 149        flush_output();
 150        for (i = call_depth; i--;)
 151                fputs("  ", stdout);
 152        if (commit->util)
 153                printf("virtual %s\n", (char *)commit->util);
 154        else {
 155                printf("%s ", find_unique_abbrev(commit->object.sha1, DEFAULT_ABBREV));
 156                if (parse_commit(commit) != 0)
 157                        printf("(bad commit)\n");
 158                else {
 159                        const char *s;
 160                        int len;
 161                        for (s = commit->buffer; *s; s++)
 162                                if (*s == '\n' && s[1] == '\n') {
 163                                        s += 2;
 164                                        break;
 165                                }
 166                        for (len = 0; s[len] && '\n' != s[len]; len++)
 167                                ; /* do nothing */
 168                        printf("%.*s\n", len, s);
 169                }
 170        }
 171}
 172
 173static int add_cacheinfo(unsigned int mode, const unsigned char *sha1,
 174                const char *path, int stage, int refresh, int options)
 175{
 176        struct cache_entry *ce;
 177        ce = make_cache_entry(mode, sha1 ? sha1 : null_sha1, path, stage, refresh);
 178        if (!ce)
 179                return error("addinfo_cache failed for path '%s'", path);
 180        return add_cache_entry(ce, options);
 181}
 182
 183/*
 184 * This is a global variable which is used in a number of places but
 185 * only written to in the 'merge' function.
 186 *
 187 * index_only == 1    => Don't leave any non-stage 0 entries in the cache and
 188 *                       don't update the working directory.
 189 *               0    => Leave unmerged entries in the cache and update
 190 *                       the working directory.
 191 */
 192static int index_only = 0;
 193
 194static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 195{
 196        parse_tree(tree);
 197        init_tree_desc(desc, tree->buffer, tree->size);
 198}
 199
 200static int git_merge_trees(int index_only,
 201                           struct tree *common,
 202                           struct tree *head,
 203                           struct tree *merge)
 204{
 205        int rc;
 206        struct tree_desc t[3];
 207        struct unpack_trees_options opts;
 208
 209        memset(&opts, 0, sizeof(opts));
 210        if (index_only)
 211                opts.index_only = 1;
 212        else
 213                opts.update = 1;
 214        opts.merge = 1;
 215        opts.head_idx = 2;
 216        opts.fn = threeway_merge;
 217        opts.src_index = &the_index;
 218        opts.dst_index = &the_index;
 219
 220        init_tree_desc_from_tree(t+0, common);
 221        init_tree_desc_from_tree(t+1, head);
 222        init_tree_desc_from_tree(t+2, merge);
 223
 224        rc = unpack_trees(3, t, &opts);
 225        cache_tree_free(&active_cache_tree);
 226        return rc;
 227}
 228
 229struct tree *write_tree_from_memory(void)
 230{
 231        struct tree *result = NULL;
 232
 233        if (unmerged_cache()) {
 234                int i;
 235                output(0, "There are unmerged index entries:");
 236                for (i = 0; i < active_nr; i++) {
 237                        struct cache_entry *ce = active_cache[i];
 238                        if (ce_stage(ce))
 239                                output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 240                }
 241                return NULL;
 242        }
 243
 244        if (!active_cache_tree)
 245                active_cache_tree = cache_tree();
 246
 247        if (!cache_tree_fully_valid(active_cache_tree) &&
 248            cache_tree_update(active_cache_tree,
 249                              active_cache, active_nr, 0, 0) < 0)
 250                die("error building trees");
 251
 252        result = lookup_tree(active_cache_tree->sha1);
 253
 254        return result;
 255}
 256
 257static int save_files_dirs(const unsigned char *sha1,
 258                const char *base, int baselen, const char *path,
 259                unsigned int mode, int stage)
 260{
 261        int len = strlen(path);
 262        char *newpath = xmalloc(baselen + len + 1);
 263        memcpy(newpath, base, baselen);
 264        memcpy(newpath + baselen, path, len);
 265        newpath[baselen + len] = '\0';
 266
 267        if (S_ISDIR(mode))
 268                path_list_insert(newpath, &current_directory_set);
 269        else
 270                path_list_insert(newpath, &current_file_set);
 271        free(newpath);
 272
 273        return READ_TREE_RECURSIVE;
 274}
 275
 276static int get_files_dirs(struct tree *tree)
 277{
 278        int n;
 279        if (read_tree_recursive(tree, "", 0, 0, NULL, save_files_dirs) != 0)
 280                return 0;
 281        n = current_file_set.nr + current_directory_set.nr;
 282        return n;
 283}
 284
 285/*
 286 * Returns an index_entry instance which doesn't have to correspond to
 287 * a real cache entry in Git's index.
 288 */
 289static struct stage_data *insert_stage_data(const char *path,
 290                struct tree *o, struct tree *a, struct tree *b,
 291                struct path_list *entries)
 292{
 293        struct path_list_item *item;
 294        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 295        get_tree_entry(o->object.sha1, path,
 296                        e->stages[1].sha, &e->stages[1].mode);
 297        get_tree_entry(a->object.sha1, path,
 298                        e->stages[2].sha, &e->stages[2].mode);
 299        get_tree_entry(b->object.sha1, path,
 300                        e->stages[3].sha, &e->stages[3].mode);
 301        item = path_list_insert(path, entries);
 302        item->util = e;
 303        return e;
 304}
 305
 306/*
 307 * Create a dictionary mapping file names to stage_data objects. The
 308 * dictionary contains one entry for every path with a non-zero stage entry.
 309 */
 310static struct path_list *get_unmerged(void)
 311{
 312        struct path_list *unmerged = xcalloc(1, sizeof(struct path_list));
 313        int i;
 314
 315        unmerged->strdup_paths = 1;
 316
 317        for (i = 0; i < active_nr; i++) {
 318                struct path_list_item *item;
 319                struct stage_data *e;
 320                struct cache_entry *ce = active_cache[i];
 321                if (!ce_stage(ce))
 322                        continue;
 323
 324                item = path_list_lookup(ce->name, unmerged);
 325                if (!item) {
 326                        item = path_list_insert(ce->name, unmerged);
 327                        item->util = xcalloc(1, sizeof(struct stage_data));
 328                }
 329                e = item->util;
 330                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 331                hashcpy(e->stages[ce_stage(ce)].sha, ce->sha1);
 332        }
 333
 334        return unmerged;
 335}
 336
 337struct rename
 338{
 339        struct diff_filepair *pair;
 340        struct stage_data *src_entry;
 341        struct stage_data *dst_entry;
 342        unsigned processed:1;
 343};
 344
 345/*
 346 * Get information of all renames which occurred between 'o_tree' and
 347 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 348 * 'b_tree') to be able to associate the correct cache entries with
 349 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 350 */
 351static struct path_list *get_renames(struct tree *tree,
 352                                        struct tree *o_tree,
 353                                        struct tree *a_tree,
 354                                        struct tree *b_tree,
 355                                        struct path_list *entries)
 356{
 357        int i;
 358        struct path_list *renames;
 359        struct diff_options opts;
 360
 361        renames = xcalloc(1, sizeof(struct path_list));
 362        diff_setup(&opts);
 363        DIFF_OPT_SET(&opts, RECURSIVE);
 364        opts.detect_rename = DIFF_DETECT_RENAME;
 365        opts.rename_limit = merge_rename_limit >= 0 ? merge_rename_limit :
 366                            diff_rename_limit >= 0 ? diff_rename_limit :
 367                            500;
 368        opts.warn_on_too_large_rename = 1;
 369        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 370        if (diff_setup_done(&opts) < 0)
 371                die("diff setup failed");
 372        diff_tree_sha1(o_tree->object.sha1, tree->object.sha1, "", &opts);
 373        diffcore_std(&opts);
 374        for (i = 0; i < diff_queued_diff.nr; ++i) {
 375                struct path_list_item *item;
 376                struct rename *re;
 377                struct diff_filepair *pair = diff_queued_diff.queue[i];
 378                if (pair->status != 'R') {
 379                        diff_free_filepair(pair);
 380                        continue;
 381                }
 382                re = xmalloc(sizeof(*re));
 383                re->processed = 0;
 384                re->pair = pair;
 385                item = path_list_lookup(re->pair->one->path, entries);
 386                if (!item)
 387                        re->src_entry = insert_stage_data(re->pair->one->path,
 388                                        o_tree, a_tree, b_tree, entries);
 389                else
 390                        re->src_entry = item->util;
 391
 392                item = path_list_lookup(re->pair->two->path, entries);
 393                if (!item)
 394                        re->dst_entry = insert_stage_data(re->pair->two->path,
 395                                        o_tree, a_tree, b_tree, entries);
 396                else
 397                        re->dst_entry = item->util;
 398                item = path_list_insert(pair->one->path, renames);
 399                item->util = re;
 400        }
 401        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 402        diff_queued_diff.nr = 0;
 403        diff_flush(&opts);
 404        return renames;
 405}
 406
 407static int update_stages(const char *path, struct diff_filespec *o,
 408                         struct diff_filespec *a, struct diff_filespec *b,
 409                         int clear)
 410{
 411        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE;
 412        if (clear)
 413                if (remove_file_from_cache(path))
 414                        return -1;
 415        if (o)
 416                if (add_cacheinfo(o->mode, o->sha1, path, 1, 0, options))
 417                        return -1;
 418        if (a)
 419                if (add_cacheinfo(a->mode, a->sha1, path, 2, 0, options))
 420                        return -1;
 421        if (b)
 422                if (add_cacheinfo(b->mode, b->sha1, path, 3, 0, options))
 423                        return -1;
 424        return 0;
 425}
 426
 427static int remove_path(const char *name)
 428{
 429        int ret;
 430        char *slash, *dirs;
 431
 432        ret = unlink(name);
 433        if (ret)
 434                return ret;
 435        dirs = xstrdup(name);
 436        while ((slash = strrchr(name, '/'))) {
 437                *slash = '\0';
 438                if (rmdir(name) != 0)
 439                        break;
 440        }
 441        free(dirs);
 442        return ret;
 443}
 444
 445static int remove_file(int clean, const char *path, int no_wd)
 446{
 447        int update_cache = index_only || clean;
 448        int update_working_directory = !index_only && !no_wd;
 449
 450        if (update_cache) {
 451                if (remove_file_from_cache(path))
 452                        return -1;
 453        }
 454        if (update_working_directory) {
 455                unlink(path);
 456                if (errno != ENOENT || errno != EISDIR)
 457                        return -1;
 458                remove_path(path);
 459        }
 460        return 0;
 461}
 462
 463static char *unique_path(const char *path, const char *branch)
 464{
 465        char *newpath = xmalloc(strlen(path) + 1 + strlen(branch) + 8 + 1);
 466        int suffix = 0;
 467        struct stat st;
 468        char *p = newpath + strlen(path);
 469        strcpy(newpath, path);
 470        *(p++) = '~';
 471        strcpy(p, branch);
 472        for (; *p; ++p)
 473                if ('/' == *p)
 474                        *p = '_';
 475        while (path_list_has_path(&current_file_set, newpath) ||
 476               path_list_has_path(&current_directory_set, newpath) ||
 477               lstat(newpath, &st) == 0)
 478                sprintf(p, "_%d", suffix++);
 479
 480        path_list_insert(newpath, &current_file_set);
 481        return newpath;
 482}
 483
 484static int mkdir_p(const char *path, unsigned long mode)
 485{
 486        /* path points to cache entries, so xstrdup before messing with it */
 487        char *buf = xstrdup(path);
 488        int result = safe_create_leading_directories(buf);
 489        free(buf);
 490        return result;
 491}
 492
 493static void flush_buffer(int fd, const char *buf, unsigned long size)
 494{
 495        while (size > 0) {
 496                long ret = write_in_full(fd, buf, size);
 497                if (ret < 0) {
 498                        /* Ignore epipe */
 499                        if (errno == EPIPE)
 500                                break;
 501                        die("merge-recursive: %s", strerror(errno));
 502                } else if (!ret) {
 503                        die("merge-recursive: disk full?");
 504                }
 505                size -= ret;
 506                buf += ret;
 507        }
 508}
 509
 510static int make_room_for_path(const char *path)
 511{
 512        int status;
 513        const char *msg = "failed to create path '%s'%s";
 514
 515        status = mkdir_p(path, 0777);
 516        if (status) {
 517                if (status == -3) {
 518                        /* something else exists */
 519                        error(msg, path, ": perhaps a D/F conflict?");
 520                        return -1;
 521                }
 522                die(msg, path, "");
 523        }
 524
 525        /* Successful unlink is good.. */
 526        if (!unlink(path))
 527                return 0;
 528        /* .. and so is no existing file */
 529        if (errno == ENOENT)
 530                return 0;
 531        /* .. but not some other error (who really cares what?) */
 532        return error(msg, path, ": perhaps a D/F conflict?");
 533}
 534
 535static void update_file_flags(const unsigned char *sha,
 536                              unsigned mode,
 537                              const char *path,
 538                              int update_cache,
 539                              int update_wd)
 540{
 541        if (index_only)
 542                update_wd = 0;
 543
 544        if (update_wd) {
 545                enum object_type type;
 546                void *buf;
 547                unsigned long size;
 548
 549                if (S_ISGITLINK(mode))
 550                        die("cannot read object %s '%s': It is a submodule!",
 551                            sha1_to_hex(sha), path);
 552
 553                buf = read_sha1_file(sha, &type, &size);
 554                if (!buf)
 555                        die("cannot read object %s '%s'", sha1_to_hex(sha), path);
 556                if (type != OBJ_BLOB)
 557                        die("blob expected for %s '%s'", sha1_to_hex(sha), path);
 558
 559                if (make_room_for_path(path) < 0) {
 560                        update_wd = 0;
 561                        goto update_index;
 562                }
 563                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 564                        int fd;
 565                        if (mode & 0100)
 566                                mode = 0777;
 567                        else
 568                                mode = 0666;
 569                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 570                        if (fd < 0)
 571                                die("failed to open %s: %s", path, strerror(errno));
 572                        flush_buffer(fd, buf, size);
 573                        close(fd);
 574                } else if (S_ISLNK(mode)) {
 575                        char *lnk = xmemdupz(buf, size);
 576                        mkdir_p(path, 0777);
 577                        unlink(path);
 578                        symlink(lnk, path);
 579                        free(lnk);
 580                } else
 581                        die("do not know what to do with %06o %s '%s'",
 582                            mode, sha1_to_hex(sha), path);
 583        }
 584 update_index:
 585        if (update_cache)
 586                add_cacheinfo(mode, sha, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 587}
 588
 589static void update_file(int clean,
 590                        const unsigned char *sha,
 591                        unsigned mode,
 592                        const char *path)
 593{
 594        update_file_flags(sha, mode, path, index_only || clean, !index_only);
 595}
 596
 597/* Low level file merging, update and removal */
 598
 599struct merge_file_info
 600{
 601        unsigned char sha[20];
 602        unsigned mode;
 603        unsigned clean:1,
 604                 merge:1;
 605};
 606
 607static void fill_mm(const unsigned char *sha1, mmfile_t *mm)
 608{
 609        unsigned long size;
 610        enum object_type type;
 611
 612        if (!hashcmp(sha1, null_sha1)) {
 613                mm->ptr = xstrdup("");
 614                mm->size = 0;
 615                return;
 616        }
 617
 618        mm->ptr = read_sha1_file(sha1, &type, &size);
 619        if (!mm->ptr || type != OBJ_BLOB)
 620                die("unable to read blob object %s", sha1_to_hex(sha1));
 621        mm->size = size;
 622}
 623
 624static int merge_3way(mmbuffer_t *result_buf,
 625                      struct diff_filespec *o,
 626                      struct diff_filespec *a,
 627                      struct diff_filespec *b,
 628                      const char *branch1,
 629                      const char *branch2)
 630{
 631        mmfile_t orig, src1, src2;
 632        char *name1, *name2;
 633        int merge_status;
 634
 635        name1 = xstrdup(mkpath("%s:%s", branch1, a->path));
 636        name2 = xstrdup(mkpath("%s:%s", branch2, b->path));
 637
 638        fill_mm(o->sha1, &orig);
 639        fill_mm(a->sha1, &src1);
 640        fill_mm(b->sha1, &src2);
 641
 642        merge_status = ll_merge(result_buf, a->path, &orig,
 643                                &src1, name1, &src2, name2,
 644                                index_only);
 645
 646        free(name1);
 647        free(name2);
 648        free(orig.ptr);
 649        free(src1.ptr);
 650        free(src2.ptr);
 651        return merge_status;
 652}
 653
 654static struct merge_file_info merge_file(struct diff_filespec *o,
 655                struct diff_filespec *a, struct diff_filespec *b,
 656                const char *branch1, const char *branch2)
 657{
 658        struct merge_file_info result;
 659        result.merge = 0;
 660        result.clean = 1;
 661
 662        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 663                result.clean = 0;
 664                if (S_ISREG(a->mode)) {
 665                        result.mode = a->mode;
 666                        hashcpy(result.sha, a->sha1);
 667                } else {
 668                        result.mode = b->mode;
 669                        hashcpy(result.sha, b->sha1);
 670                }
 671        } else {
 672                if (!sha_eq(a->sha1, o->sha1) && !sha_eq(b->sha1, o->sha1))
 673                        result.merge = 1;
 674
 675                /*
 676                 * Merge modes
 677                 */
 678                if (a->mode == b->mode || a->mode == o->mode)
 679                        result.mode = b->mode;
 680                else {
 681                        result.mode = a->mode;
 682                        if (b->mode != o->mode) {
 683                                result.clean = 0;
 684                                result.merge = 1;
 685                        }
 686                }
 687
 688                if (sha_eq(a->sha1, b->sha1) || sha_eq(a->sha1, o->sha1))
 689                        hashcpy(result.sha, b->sha1);
 690                else if (sha_eq(b->sha1, o->sha1))
 691                        hashcpy(result.sha, a->sha1);
 692                else if (S_ISREG(a->mode)) {
 693                        mmbuffer_t result_buf;
 694                        int merge_status;
 695
 696                        merge_status = merge_3way(&result_buf, o, a, b,
 697                                                  branch1, branch2);
 698
 699                        if ((merge_status < 0) || !result_buf.ptr)
 700                                die("Failed to execute internal merge");
 701
 702                        if (write_sha1_file(result_buf.ptr, result_buf.size,
 703                                            blob_type, result.sha))
 704                                die("Unable to add %s to database",
 705                                    a->path);
 706
 707                        free(result_buf.ptr);
 708                        result.clean = (merge_status == 0);
 709                } else if (S_ISGITLINK(a->mode)) {
 710                        result.clean = 0;
 711                        hashcpy(result.sha, a->sha1);
 712                } else if (S_ISLNK(a->mode)) {
 713                        hashcpy(result.sha, a->sha1);
 714
 715                        if (!sha_eq(a->sha1, b->sha1))
 716                                result.clean = 0;
 717                } else {
 718                        die("unsupported object type in the tree");
 719                }
 720        }
 721
 722        return result;
 723}
 724
 725static void conflict_rename_rename(struct rename *ren1,
 726                                   const char *branch1,
 727                                   struct rename *ren2,
 728                                   const char *branch2)
 729{
 730        char *del[2];
 731        int delp = 0;
 732        const char *ren1_dst = ren1->pair->two->path;
 733        const char *ren2_dst = ren2->pair->two->path;
 734        const char *dst_name1 = ren1_dst;
 735        const char *dst_name2 = ren2_dst;
 736        if (path_list_has_path(&current_directory_set, ren1_dst)) {
 737                dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
 738                output(1, "%s is a directory in %s added as %s instead",
 739                       ren1_dst, branch2, dst_name1);
 740                remove_file(0, ren1_dst, 0);
 741        }
 742        if (path_list_has_path(&current_directory_set, ren2_dst)) {
 743                dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
 744                output(1, "%s is a directory in %s added as %s instead",
 745                       ren2_dst, branch1, dst_name2);
 746                remove_file(0, ren2_dst, 0);
 747        }
 748        if (index_only) {
 749                remove_file_from_cache(dst_name1);
 750                remove_file_from_cache(dst_name2);
 751                /*
 752                 * Uncomment to leave the conflicting names in the resulting tree
 753                 *
 754                 * update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, dst_name1);
 755                 * update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, dst_name2);
 756                 */
 757        } else {
 758                update_stages(dst_name1, NULL, ren1->pair->two, NULL, 1);
 759                update_stages(dst_name2, NULL, NULL, ren2->pair->two, 1);
 760        }
 761        while (delp--)
 762                free(del[delp]);
 763}
 764
 765static void conflict_rename_dir(struct rename *ren1,
 766                                const char *branch1)
 767{
 768        char *new_path = unique_path(ren1->pair->two->path, branch1);
 769        output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
 770        remove_file(0, ren1->pair->two->path, 0);
 771        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 772        free(new_path);
 773}
 774
 775static void conflict_rename_rename_2(struct rename *ren1,
 776                                     const char *branch1,
 777                                     struct rename *ren2,
 778                                     const char *branch2)
 779{
 780        char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 781        char *new_path2 = unique_path(ren2->pair->two->path, branch2);
 782        output(1, "Renamed %s to %s and %s to %s instead",
 783               ren1->pair->one->path, new_path1,
 784               ren2->pair->one->path, new_path2);
 785        remove_file(0, ren1->pair->two->path, 0);
 786        update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path1);
 787        update_file(0, ren2->pair->two->sha1, ren2->pair->two->mode, new_path2);
 788        free(new_path2);
 789        free(new_path1);
 790}
 791
 792static int process_renames(struct path_list *a_renames,
 793                           struct path_list *b_renames,
 794                           const char *a_branch,
 795                           const char *b_branch)
 796{
 797        int clean_merge = 1, i, j;
 798        struct path_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};
 799        const struct rename *sre;
 800
 801        for (i = 0; i < a_renames->nr; i++) {
 802                sre = a_renames->items[i].util;
 803                path_list_insert(sre->pair->two->path, &a_by_dst)->util
 804                        = sre->dst_entry;
 805        }
 806        for (i = 0; i < b_renames->nr; i++) {
 807                sre = b_renames->items[i].util;
 808                path_list_insert(sre->pair->two->path, &b_by_dst)->util
 809                        = sre->dst_entry;
 810        }
 811
 812        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
 813                int compare;
 814                char *src;
 815                struct path_list *renames1, *renames2, *renames2Dst;
 816                struct rename *ren1 = NULL, *ren2 = NULL;
 817                const char *branch1, *branch2;
 818                const char *ren1_src, *ren1_dst;
 819
 820                if (i >= a_renames->nr) {
 821                        compare = 1;
 822                        ren2 = b_renames->items[j++].util;
 823                } else if (j >= b_renames->nr) {
 824                        compare = -1;
 825                        ren1 = a_renames->items[i++].util;
 826                } else {
 827                        compare = strcmp(a_renames->items[i].path,
 828                                        b_renames->items[j].path);
 829                        if (compare <= 0)
 830                                ren1 = a_renames->items[i++].util;
 831                        if (compare >= 0)
 832                                ren2 = b_renames->items[j++].util;
 833                }
 834
 835                /* TODO: refactor, so that 1/2 are not needed */
 836                if (ren1) {
 837                        renames1 = a_renames;
 838                        renames2 = b_renames;
 839                        renames2Dst = &b_by_dst;
 840                        branch1 = a_branch;
 841                        branch2 = b_branch;
 842                } else {
 843                        struct rename *tmp;
 844                        renames1 = b_renames;
 845                        renames2 = a_renames;
 846                        renames2Dst = &a_by_dst;
 847                        branch1 = b_branch;
 848                        branch2 = a_branch;
 849                        tmp = ren2;
 850                        ren2 = ren1;
 851                        ren1 = tmp;
 852                }
 853                src = ren1->pair->one->path;
 854
 855                ren1->dst_entry->processed = 1;
 856                ren1->src_entry->processed = 1;
 857
 858                if (ren1->processed)
 859                        continue;
 860                ren1->processed = 1;
 861
 862                ren1_src = ren1->pair->one->path;
 863                ren1_dst = ren1->pair->two->path;
 864
 865                if (ren2) {
 866                        const char *ren2_src = ren2->pair->one->path;
 867                        const char *ren2_dst = ren2->pair->two->path;
 868                        /* Renamed in 1 and renamed in 2 */
 869                        if (strcmp(ren1_src, ren2_src) != 0)
 870                                die("ren1.src != ren2.src");
 871                        ren2->dst_entry->processed = 1;
 872                        ren2->processed = 1;
 873                        if (strcmp(ren1_dst, ren2_dst) != 0) {
 874                                clean_merge = 0;
 875                                output(1, "CONFLICT (rename/rename): "
 876                                       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 877                                       "rename \"%s\"->\"%s\" in \"%s\"%s",
 878                                       src, ren1_dst, branch1,
 879                                       src, ren2_dst, branch2,
 880                                       index_only ? " (left unresolved)": "");
 881                                if (index_only) {
 882                                        remove_file_from_cache(src);
 883                                        update_file(0, ren1->pair->one->sha1,
 884                                                    ren1->pair->one->mode, src);
 885                                }
 886                                conflict_rename_rename(ren1, branch1, ren2, branch2);
 887                        } else {
 888                                struct merge_file_info mfi;
 889                                remove_file(1, ren1_src, 1);
 890                                mfi = merge_file(ren1->pair->one,
 891                                                 ren1->pair->two,
 892                                                 ren2->pair->two,
 893                                                 branch1,
 894                                                 branch2);
 895                                if (mfi.merge || !mfi.clean)
 896                                        output(1, "Renamed %s->%s", src, ren1_dst);
 897
 898                                if (mfi.merge)
 899                                        output(2, "Auto-merged %s", ren1_dst);
 900
 901                                if (!mfi.clean) {
 902                                        output(1, "CONFLICT (content): merge conflict in %s",
 903                                               ren1_dst);
 904                                        clean_merge = 0;
 905
 906                                        if (!index_only)
 907                                                update_stages(ren1_dst,
 908                                                              ren1->pair->one,
 909                                                              ren1->pair->two,
 910                                                              ren2->pair->two,
 911                                                              1 /* clear */);
 912                                }
 913                                update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 914                        }
 915                } else {
 916                        /* Renamed in 1, maybe changed in 2 */
 917                        struct path_list_item *item;
 918                        /* we only use sha1 and mode of these */
 919                        struct diff_filespec src_other, dst_other;
 920                        int try_merge, stage = a_renames == renames1 ? 3: 2;
 921
 922                        remove_file(1, ren1_src, index_only || stage == 3);
 923
 924                        hashcpy(src_other.sha1, ren1->src_entry->stages[stage].sha);
 925                        src_other.mode = ren1->src_entry->stages[stage].mode;
 926                        hashcpy(dst_other.sha1, ren1->dst_entry->stages[stage].sha);
 927                        dst_other.mode = ren1->dst_entry->stages[stage].mode;
 928
 929                        try_merge = 0;
 930
 931                        if (path_list_has_path(&current_directory_set, ren1_dst)) {
 932                                clean_merge = 0;
 933                                output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
 934                                       " directory %s added in %s",
 935                                       ren1_src, ren1_dst, branch1,
 936                                       ren1_dst, branch2);
 937                                conflict_rename_dir(ren1, branch1);
 938                        } else if (sha_eq(src_other.sha1, null_sha1)) {
 939                                clean_merge = 0;
 940                                output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
 941                                       "and deleted in %s",
 942                                       ren1_src, ren1_dst, branch1,
 943                                       branch2);
 944                                update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, ren1_dst);
 945                        } else if (!sha_eq(dst_other.sha1, null_sha1)) {
 946                                const char *new_path;
 947                                clean_merge = 0;
 948                                try_merge = 1;
 949                                output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
 950                                       "%s added in %s",
 951                                       ren1_src, ren1_dst, branch1,
 952                                       ren1_dst, branch2);
 953                                new_path = unique_path(ren1_dst, branch2);
 954                                output(1, "Added as %s instead", new_path);
 955                                update_file(0, dst_other.sha1, dst_other.mode, new_path);
 956                        } else if ((item = path_list_lookup(ren1_dst, renames2Dst))) {
 957                                ren2 = item->util;
 958                                clean_merge = 0;
 959                                ren2->processed = 1;
 960                                output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
 961                                       "Renamed %s->%s in %s",
 962                                       ren1_src, ren1_dst, branch1,
 963                                       ren2->pair->one->path, ren2->pair->two->path, branch2);
 964                                conflict_rename_rename_2(ren1, branch1, ren2, branch2);
 965                        } else
 966                                try_merge = 1;
 967
 968                        if (try_merge) {
 969                                struct diff_filespec *o, *a, *b;
 970                                struct merge_file_info mfi;
 971                                src_other.path = (char *)ren1_src;
 972
 973                                o = ren1->pair->one;
 974                                if (a_renames == renames1) {
 975                                        a = ren1->pair->two;
 976                                        b = &src_other;
 977                                } else {
 978                                        b = ren1->pair->two;
 979                                        a = &src_other;
 980                                }
 981                                mfi = merge_file(o, a, b,
 982                                                a_branch, b_branch);
 983
 984                                if (mfi.clean &&
 985                                    sha_eq(mfi.sha, ren1->pair->two->sha1) &&
 986                                    mfi.mode == ren1->pair->two->mode)
 987                                        /*
 988                                         * This messaged is part of
 989                                         * t6022 test. If you change
 990                                         * it update the test too.
 991                                         */
 992                                        output(3, "Skipped %s (merged same as existing)", ren1_dst);
 993                                else {
 994                                        if (mfi.merge || !mfi.clean)
 995                                                output(1, "Renamed %s => %s", ren1_src, ren1_dst);
 996                                        if (mfi.merge)
 997                                                output(2, "Auto-merged %s", ren1_dst);
 998                                        if (!mfi.clean) {
 999                                                output(1, "CONFLICT (rename/modify): Merge conflict in %s",
1000                                                       ren1_dst);
1001                                                clean_merge = 0;
1002
1003                                                if (!index_only)
1004                                                        update_stages(ren1_dst,
1005                                                                      o, a, b, 1);
1006                                        }
1007                                        update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
1008                                }
1009                        }
1010                }
1011        }
1012        path_list_clear(&a_by_dst, 0);
1013        path_list_clear(&b_by_dst, 0);
1014
1015        return clean_merge;
1016}
1017
1018static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
1019{
1020        return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
1021}
1022
1023/* Per entry merge function */
1024static int process_entry(const char *path, struct stage_data *entry,
1025                         const char *branch1,
1026                         const char *branch2)
1027{
1028        /*
1029        printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");
1030        print_index_entry("\tpath: ", entry);
1031        */
1032        int clean_merge = 1;
1033        unsigned o_mode = entry->stages[1].mode;
1034        unsigned a_mode = entry->stages[2].mode;
1035        unsigned b_mode = entry->stages[3].mode;
1036        unsigned char *o_sha = stage_sha(entry->stages[1].sha, o_mode);
1037        unsigned char *a_sha = stage_sha(entry->stages[2].sha, a_mode);
1038        unsigned char *b_sha = stage_sha(entry->stages[3].sha, b_mode);
1039
1040        if (o_sha && (!a_sha || !b_sha)) {
1041                /* Case A: Deleted in one */
1042                if ((!a_sha && !b_sha) ||
1043                    (sha_eq(a_sha, o_sha) && !b_sha) ||
1044                    (!a_sha && sha_eq(b_sha, o_sha))) {
1045                        /* Deleted in both or deleted in one and
1046                         * unchanged in the other */
1047                        if (a_sha)
1048                                output(2, "Removed %s", path);
1049                        /* do not touch working file if it did not exist */
1050                        remove_file(1, path, !a_sha);
1051                } else {
1052                        /* Deleted in one and changed in the other */
1053                        clean_merge = 0;
1054                        if (!a_sha) {
1055                                output(1, "CONFLICT (delete/modify): %s deleted in %s "
1056                                       "and modified in %s. Version %s of %s left in tree.",
1057                                       path, branch1,
1058                                       branch2, branch2, path);
1059                                update_file(0, b_sha, b_mode, path);
1060                        } else {
1061                                output(1, "CONFLICT (delete/modify): %s deleted in %s "
1062                                       "and modified in %s. Version %s of %s left in tree.",
1063                                       path, branch2,
1064                                       branch1, branch1, path);
1065                                update_file(0, a_sha, a_mode, path);
1066                        }
1067                }
1068
1069        } else if ((!o_sha && a_sha && !b_sha) ||
1070                   (!o_sha && !a_sha && b_sha)) {
1071                /* Case B: Added in one. */
1072                const char *add_branch;
1073                const char *other_branch;
1074                unsigned mode;
1075                const unsigned char *sha;
1076                const char *conf;
1077
1078                if (a_sha) {
1079                        add_branch = branch1;
1080                        other_branch = branch2;
1081                        mode = a_mode;
1082                        sha = a_sha;
1083                        conf = "file/directory";
1084                } else {
1085                        add_branch = branch2;
1086                        other_branch = branch1;
1087                        mode = b_mode;
1088                        sha = b_sha;
1089                        conf = "directory/file";
1090                }
1091                if (path_list_has_path(&current_directory_set, path)) {
1092                        const char *new_path = unique_path(path, add_branch);
1093                        clean_merge = 0;
1094                        output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
1095                               "Added %s as %s",
1096                               conf, path, other_branch, path, new_path);
1097                        remove_file(0, path, 0);
1098                        update_file(0, sha, mode, new_path);
1099                } else {
1100                        output(2, "Added %s", path);
1101                        update_file(1, sha, mode, path);
1102                }
1103        } else if (a_sha && b_sha) {
1104                /* Case C: Added in both (check for same permissions) and */
1105                /* case D: Modified in both, but differently. */
1106                const char *reason = "content";
1107                struct merge_file_info mfi;
1108                struct diff_filespec o, a, b;
1109
1110                if (!o_sha) {
1111                        reason = "add/add";
1112                        o_sha = (unsigned char *)null_sha1;
1113                }
1114                output(2, "Auto-merged %s", path);
1115                o.path = a.path = b.path = (char *)path;
1116                hashcpy(o.sha1, o_sha);
1117                o.mode = o_mode;
1118                hashcpy(a.sha1, a_sha);
1119                a.mode = a_mode;
1120                hashcpy(b.sha1, b_sha);
1121                b.mode = b_mode;
1122
1123                mfi = merge_file(&o, &a, &b,
1124                                 branch1, branch2);
1125
1126                clean_merge = mfi.clean;
1127                if (mfi.clean)
1128                        update_file(1, mfi.sha, mfi.mode, path);
1129                else if (S_ISGITLINK(mfi.mode))
1130                        output(1, "CONFLICT (submodule): Merge conflict in %s "
1131                               "- needs %s", path, sha1_to_hex(b.sha1));
1132                else {
1133                        output(1, "CONFLICT (%s): Merge conflict in %s",
1134                                        reason, path);
1135
1136                        if (index_only)
1137                                update_file(0, mfi.sha, mfi.mode, path);
1138                        else
1139                                update_file_flags(mfi.sha, mfi.mode, path,
1140                                              0 /* update_cache */, 1 /* update_working_directory */);
1141                }
1142        } else if (!o_sha && !a_sha && !b_sha) {
1143                /*
1144                 * this entry was deleted altogether. a_mode == 0 means
1145                 * we had that path and want to actively remove it.
1146                 */
1147                remove_file(1, path, !a_mode);
1148        } else
1149                die("Fatal merge failure, shouldn't happen.");
1150
1151        return clean_merge;
1152}
1153
1154int merge_trees(struct tree *head,
1155                struct tree *merge,
1156                struct tree *common,
1157                const char *branch1,
1158                const char *branch2,
1159                struct tree **result)
1160{
1161        int code, clean;
1162
1163        if (subtree_merge) {
1164                merge = shift_tree_object(head, merge);
1165                common = shift_tree_object(head, common);
1166        }
1167
1168        if (sha_eq(common->object.sha1, merge->object.sha1)) {
1169                output(0, "Already uptodate!");
1170                *result = head;
1171                return 1;
1172        }
1173
1174        code = git_merge_trees(index_only, common, head, merge);
1175
1176        if (code != 0)
1177                die("merging of trees %s and %s failed",
1178                    sha1_to_hex(head->object.sha1),
1179                    sha1_to_hex(merge->object.sha1));
1180
1181        if (unmerged_cache()) {
1182                struct path_list *entries, *re_head, *re_merge;
1183                int i;
1184                path_list_clear(&current_file_set, 1);
1185                path_list_clear(&current_directory_set, 1);
1186                get_files_dirs(head);
1187                get_files_dirs(merge);
1188
1189                entries = get_unmerged();
1190                re_head  = get_renames(head, common, head, merge, entries);
1191                re_merge = get_renames(merge, common, head, merge, entries);
1192                clean = process_renames(re_head, re_merge,
1193                                branch1, branch2);
1194                for (i = 0; i < entries->nr; i++) {
1195                        const char *path = entries->items[i].path;
1196                        struct stage_data *e = entries->items[i].util;
1197                        if (!e->processed
1198                                && !process_entry(path, e, branch1, branch2))
1199                                clean = 0;
1200                }
1201
1202                path_list_clear(re_merge, 0);
1203                path_list_clear(re_head, 0);
1204                path_list_clear(entries, 1);
1205
1206        }
1207        else
1208                clean = 1;
1209
1210        if (index_only)
1211                *result = write_tree_from_memory();
1212
1213        return clean;
1214}
1215
1216static struct commit_list *reverse_commit_list(struct commit_list *list)
1217{
1218        struct commit_list *next = NULL, *current, *backup;
1219        for (current = list; current; current = backup) {
1220                backup = current->next;
1221                current->next = next;
1222                next = current;
1223        }
1224        return next;
1225}
1226
1227/*
1228 * Merge the commits h1 and h2, return the resulting virtual
1229 * commit object and a flag indicating the cleanness of the merge.
1230 */
1231int merge_recursive(struct commit *h1,
1232                    struct commit *h2,
1233                    const char *branch1,
1234                    const char *branch2,
1235                    struct commit_list *ca,
1236                    struct commit **result)
1237{
1238        struct commit_list *iter;
1239        struct commit *merged_common_ancestors;
1240        struct tree *mrtree = mrtree;
1241        int clean;
1242
1243        if (show(4)) {
1244                output(4, "Merging:");
1245                output_commit_title(h1);
1246                output_commit_title(h2);
1247        }
1248
1249        if (!ca) {
1250                ca = get_merge_bases(h1, h2, 1);
1251                ca = reverse_commit_list(ca);
1252        }
1253
1254        if (show(5)) {
1255                output(5, "found %u common ancestor(s):", commit_list_count(ca));
1256                for (iter = ca; iter; iter = iter->next)
1257                        output_commit_title(iter->item);
1258        }
1259
1260        merged_common_ancestors = pop_commit(&ca);
1261        if (merged_common_ancestors == NULL) {
1262                /* if there is no common ancestor, make an empty tree */
1263                struct tree *tree = xcalloc(1, sizeof(struct tree));
1264
1265                tree->object.parsed = 1;
1266                tree->object.type = OBJ_TREE;
1267                pretend_sha1_file(NULL, 0, OBJ_TREE, tree->object.sha1);
1268                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
1269        }
1270
1271        for (iter = ca; iter; iter = iter->next) {
1272                call_depth++;
1273                /*
1274                 * When the merge fails, the result contains files
1275                 * with conflict markers. The cleanness flag is
1276                 * ignored, it was never actually used, as result of
1277                 * merge_trees has always overwritten it: the committed
1278                 * "conflicts" were already resolved.
1279                 */
1280                discard_cache();
1281                merge_recursive(merged_common_ancestors, iter->item,
1282                                "Temporary merge branch 1",
1283                                "Temporary merge branch 2",
1284                                NULL,
1285                                &merged_common_ancestors);
1286                call_depth--;
1287
1288                if (!merged_common_ancestors)
1289                        die("merge returned no commit");
1290        }
1291
1292        discard_cache();
1293        if (!call_depth) {
1294                read_cache();
1295                index_only = 0;
1296        } else
1297                index_only = 1;
1298
1299        clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
1300                            branch1, branch2, &mrtree);
1301
1302        if (index_only) {
1303                *result = make_virtual_commit(mrtree, "merged tree");
1304                commit_list_insert(h1, &(*result)->parents);
1305                commit_list_insert(h2, &(*result)->parents->next);
1306        }
1307        flush_output();
1308        return clean;
1309}
1310
1311static const char *better_branch_name(const char *branch)
1312{
1313        static char githead_env[8 + 40 + 1];
1314        char *name;
1315
1316        if (strlen(branch) != 40)
1317                return branch;
1318        sprintf(githead_env, "GITHEAD_%s", branch);
1319        name = getenv(githead_env);
1320        return name ? name : branch;
1321}
1322
1323static struct commit *get_ref(const char *ref)
1324{
1325        unsigned char sha1[20];
1326        struct object *object;
1327
1328        if (get_sha1(ref, sha1))
1329                die("Could not resolve ref '%s'", ref);
1330        object = deref_tag(parse_object(sha1), ref, strlen(ref));
1331        if (!object)
1332                return NULL;
1333        if (object->type == OBJ_TREE)
1334                return make_virtual_commit((struct tree*)object,
1335                        better_branch_name(ref));
1336        if (object->type != OBJ_COMMIT)
1337                return NULL;
1338        if (parse_commit((struct commit *)object))
1339                die("Could not parse commit '%s'", sha1_to_hex(object->sha1));
1340        return (struct commit *)object;
1341}
1342
1343static int merge_config(const char *var, const char *value, void *cb)
1344{
1345        if (!strcasecmp(var, "merge.verbosity")) {
1346                verbosity = git_config_int(var, value);
1347                return 0;
1348        }
1349        if (!strcasecmp(var, "diff.renamelimit")) {
1350                diff_rename_limit = git_config_int(var, value);
1351                return 0;
1352        }
1353        if (!strcasecmp(var, "merge.renamelimit")) {
1354                merge_rename_limit = git_config_int(var, value);
1355                return 0;
1356        }
1357        return git_default_config(var, value, cb);
1358}
1359
1360int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
1361{
1362        static const char *bases[20];
1363        static unsigned bases_count = 0;
1364        int i, clean;
1365        const char *branch1, *branch2;
1366        struct commit *result, *h1, *h2;
1367        struct commit_list *ca = NULL;
1368        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
1369        int index_fd;
1370
1371        if (argv[0]) {
1372                int namelen = strlen(argv[0]);
1373                if (8 < namelen &&
1374                    !strcmp(argv[0] + namelen - 8, "-subtree"))
1375                        subtree_merge = 1;
1376        }
1377
1378        git_config(merge_config, NULL);
1379        if (getenv("GIT_MERGE_VERBOSITY"))
1380                verbosity = strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
1381
1382        if (argc < 4)
1383                die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
1384
1385        for (i = 1; i < argc; ++i) {
1386                if (!strcmp(argv[i], "--"))
1387                        break;
1388                if (bases_count < sizeof(bases)/sizeof(*bases))
1389                        bases[bases_count++] = argv[i];
1390        }
1391        if (argc - i != 3) /* "--" "<head>" "<remote>" */
1392                die("Not handling anything other than two heads merge.");
1393        if (verbosity >= 5)
1394                buffer_output = 0;
1395
1396        branch1 = argv[++i];
1397        branch2 = argv[++i];
1398
1399        h1 = get_ref(branch1);
1400        h2 = get_ref(branch2);
1401
1402        branch1 = better_branch_name(branch1);
1403        branch2 = better_branch_name(branch2);
1404
1405        if (show(3))
1406                printf("Merging %s with %s\n", branch1, branch2);
1407
1408        index_fd = hold_locked_index(lock, 1);
1409
1410        for (i = 0; i < bases_count; i++) {
1411                struct commit *ancestor = get_ref(bases[i]);
1412                ca = commit_list_insert(ancestor, &ca);
1413        }
1414        clean = merge_recursive(h1, h2, branch1, branch2, ca, &result);
1415
1416        if (active_cache_changed &&
1417            (write_cache(index_fd, active_cache, active_nr) ||
1418             commit_locked_index(lock)))
1419                        die ("unable to write %s", get_index_file());
1420
1421        return clean ? 0: 1;
1422}