merge-recursive.con commit Merge branch 'en/remove-stripspace' (37cba00)
   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 "config.h"
   8#include "advice.h"
   9#include "lockfile.h"
  10#include "cache-tree.h"
  11#include "commit.h"
  12#include "blob.h"
  13#include "builtin.h"
  14#include "tree-walk.h"
  15#include "diff.h"
  16#include "diffcore.h"
  17#include "tag.h"
  18#include "unpack-trees.h"
  19#include "string-list.h"
  20#include "xdiff-interface.h"
  21#include "ll-merge.h"
  22#include "attr.h"
  23#include "merge-recursive.h"
  24#include "dir.h"
  25#include "submodule.h"
  26
  27struct path_hashmap_entry {
  28        struct hashmap_entry e;
  29        char path[FLEX_ARRAY];
  30};
  31
  32static int path_hashmap_cmp(const void *cmp_data,
  33                            const void *entry,
  34                            const void *entry_or_key,
  35                            const void *keydata)
  36{
  37        const struct path_hashmap_entry *a = entry;
  38        const struct path_hashmap_entry *b = entry_or_key;
  39        const char *key = keydata;
  40
  41        if (ignore_case)
  42                return strcasecmp(a->path, key ? key : b->path);
  43        else
  44                return strcmp(a->path, key ? key : b->path);
  45}
  46
  47static unsigned int path_hash(const char *path)
  48{
  49        return ignore_case ? strihash(path) : strhash(path);
  50}
  51
  52static void flush_output(struct merge_options *o)
  53{
  54        if (o->buffer_output < 2 && o->obuf.len) {
  55                fputs(o->obuf.buf, stdout);
  56                strbuf_reset(&o->obuf);
  57        }
  58}
  59
  60static int err(struct merge_options *o, const char *err, ...)
  61{
  62        va_list params;
  63
  64        if (o->buffer_output < 2)
  65                flush_output(o);
  66        else {
  67                strbuf_complete(&o->obuf, '\n');
  68                strbuf_addstr(&o->obuf, "error: ");
  69        }
  70        va_start(params, err);
  71        strbuf_vaddf(&o->obuf, err, params);
  72        va_end(params);
  73        if (o->buffer_output > 1)
  74                strbuf_addch(&o->obuf, '\n');
  75        else {
  76                error("%s", o->obuf.buf);
  77                strbuf_reset(&o->obuf);
  78        }
  79
  80        return -1;
  81}
  82
  83static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  84                                      const char *subtree_shift)
  85{
  86        struct object_id shifted;
  87
  88        if (!*subtree_shift) {
  89                shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
  90        } else {
  91                shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
  92                              subtree_shift);
  93        }
  94        if (!oidcmp(&two->object.oid, &shifted))
  95                return two;
  96        return lookup_tree(&shifted);
  97}
  98
  99static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 100{
 101        struct commit *commit = alloc_commit_node();
 102
 103        set_merge_remote_desc(commit, comment, (struct object *)commit);
 104        commit->tree = tree;
 105        commit->object.parsed = 1;
 106        return commit;
 107}
 108
 109/*
 110 * Since we use get_tree_entry(), which does not put the read object into
 111 * the object pool, we cannot rely on a == b.
 112 */
 113static int oid_eq(const struct object_id *a, const struct object_id *b)
 114{
 115        if (!a && !b)
 116                return 2;
 117        return a && b && oidcmp(a, b) == 0;
 118}
 119
 120enum rename_type {
 121        RENAME_NORMAL = 0,
 122        RENAME_DELETE,
 123        RENAME_ONE_FILE_TO_ONE,
 124        RENAME_ONE_FILE_TO_TWO,
 125        RENAME_TWO_FILES_TO_ONE
 126};
 127
 128struct rename_conflict_info {
 129        enum rename_type rename_type;
 130        struct diff_filepair *pair1;
 131        struct diff_filepair *pair2;
 132        const char *branch1;
 133        const char *branch2;
 134        struct stage_data *dst_entry1;
 135        struct stage_data *dst_entry2;
 136        struct diff_filespec ren1_other;
 137        struct diff_filespec ren2_other;
 138};
 139
 140/*
 141 * Since we want to write the index eventually, we cannot reuse the index
 142 * for these (temporary) data.
 143 */
 144struct stage_data {
 145        struct {
 146                unsigned mode;
 147                struct object_id oid;
 148        } stages[4];
 149        struct rename_conflict_info *rename_conflict_info;
 150        unsigned processed:1;
 151};
 152
 153static inline void setup_rename_conflict_info(enum rename_type rename_type,
 154                                              struct diff_filepair *pair1,
 155                                              struct diff_filepair *pair2,
 156                                              const char *branch1,
 157                                              const char *branch2,
 158                                              struct stage_data *dst_entry1,
 159                                              struct stage_data *dst_entry2,
 160                                              struct merge_options *o,
 161                                              struct stage_data *src_entry1,
 162                                              struct stage_data *src_entry2)
 163{
 164        struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
 165        ci->rename_type = rename_type;
 166        ci->pair1 = pair1;
 167        ci->branch1 = branch1;
 168        ci->branch2 = branch2;
 169
 170        ci->dst_entry1 = dst_entry1;
 171        dst_entry1->rename_conflict_info = ci;
 172        dst_entry1->processed = 0;
 173
 174        assert(!pair2 == !dst_entry2);
 175        if (dst_entry2) {
 176                ci->dst_entry2 = dst_entry2;
 177                ci->pair2 = pair2;
 178                dst_entry2->rename_conflict_info = ci;
 179        }
 180
 181        if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 182                /*
 183                 * For each rename, there could have been
 184                 * modifications on the side of history where that
 185                 * file was not renamed.
 186                 */
 187                int ostage1 = o->branch1 == branch1 ? 3 : 2;
 188                int ostage2 = ostage1 ^ 1;
 189
 190                ci->ren1_other.path = pair1->one->path;
 191                oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 192                ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 193
 194                ci->ren2_other.path = pair2->one->path;
 195                oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 196                ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 197        }
 198}
 199
 200static int show(struct merge_options *o, int v)
 201{
 202        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 203}
 204
 205__attribute__((format (printf, 3, 4)))
 206static void output(struct merge_options *o, int v, const char *fmt, ...)
 207{
 208        va_list ap;
 209
 210        if (!show(o, v))
 211                return;
 212
 213        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 214
 215        va_start(ap, fmt);
 216        strbuf_vaddf(&o->obuf, fmt, ap);
 217        va_end(ap);
 218
 219        strbuf_addch(&o->obuf, '\n');
 220        if (!o->buffer_output)
 221                flush_output(o);
 222}
 223
 224static void output_commit_title(struct merge_options *o, struct commit *commit)
 225{
 226        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 227        if (commit->util)
 228                strbuf_addf(&o->obuf, "virtual %s\n",
 229                        merge_remote_util(commit)->name);
 230        else {
 231                strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
 232                                         DEFAULT_ABBREV);
 233                strbuf_addch(&o->obuf, ' ');
 234                if (parse_commit(commit) != 0)
 235                        strbuf_addstr(&o->obuf, _("(bad commit)\n"));
 236                else {
 237                        const char *title;
 238                        const char *msg = get_commit_buffer(commit, NULL);
 239                        int len = find_commit_subject(msg, &title);
 240                        if (len)
 241                                strbuf_addf(&o->obuf, "%.*s\n", len, title);
 242                        unuse_commit_buffer(commit, msg);
 243                }
 244        }
 245        flush_output(o);
 246}
 247
 248static int add_cacheinfo(struct merge_options *o,
 249                unsigned int mode, const struct object_id *oid,
 250                const char *path, int stage, int refresh, int options)
 251{
 252        struct cache_entry *ce;
 253        int ret;
 254
 255        ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
 256        if (!ce)
 257                return err(o, _("addinfo_cache failed for path '%s'"), path);
 258
 259        ret = add_cache_entry(ce, options);
 260        if (refresh) {
 261                struct cache_entry *nce;
 262
 263                nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 264                if (!nce)
 265                        return err(o, _("addinfo_cache failed for path '%s'"), path);
 266                if (nce != ce)
 267                        ret = add_cache_entry(nce, options);
 268        }
 269        return ret;
 270}
 271
 272static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 273{
 274        parse_tree(tree);
 275        init_tree_desc(desc, tree->buffer, tree->size);
 276}
 277
 278static int git_merge_trees(int index_only,
 279                           struct tree *common,
 280                           struct tree *head,
 281                           struct tree *merge)
 282{
 283        int rc;
 284        struct tree_desc t[3];
 285        struct unpack_trees_options opts;
 286
 287        memset(&opts, 0, sizeof(opts));
 288        if (index_only)
 289                opts.index_only = 1;
 290        else
 291                opts.update = 1;
 292        opts.merge = 1;
 293        opts.head_idx = 2;
 294        opts.fn = threeway_merge;
 295        opts.src_index = &the_index;
 296        opts.dst_index = &the_index;
 297        setup_unpack_trees_porcelain(&opts, "merge");
 298
 299        init_tree_desc_from_tree(t+0, common);
 300        init_tree_desc_from_tree(t+1, head);
 301        init_tree_desc_from_tree(t+2, merge);
 302
 303        rc = unpack_trees(3, t, &opts);
 304        cache_tree_free(&active_cache_tree);
 305        return rc;
 306}
 307
 308struct tree *write_tree_from_memory(struct merge_options *o)
 309{
 310        struct tree *result = NULL;
 311
 312        if (unmerged_cache()) {
 313                int i;
 314                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 315                for (i = 0; i < active_nr; i++) {
 316                        const struct cache_entry *ce = active_cache[i];
 317                        if (ce_stage(ce))
 318                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 319                                        (int)ce_namelen(ce), ce->name);
 320                }
 321                die("BUG: unmerged index entries in merge-recursive.c");
 322        }
 323
 324        if (!active_cache_tree)
 325                active_cache_tree = cache_tree();
 326
 327        if (!cache_tree_fully_valid(active_cache_tree) &&
 328            cache_tree_update(&the_index, 0) < 0) {
 329                err(o, _("error building trees"));
 330                return NULL;
 331        }
 332
 333        result = lookup_tree(&active_cache_tree->oid);
 334
 335        return result;
 336}
 337
 338static int save_files_dirs(const unsigned char *sha1,
 339                struct strbuf *base, const char *path,
 340                unsigned int mode, int stage, void *context)
 341{
 342        struct path_hashmap_entry *entry;
 343        int baselen = base->len;
 344        struct merge_options *o = context;
 345
 346        strbuf_addstr(base, path);
 347
 348        FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 349        hashmap_entry_init(entry, path_hash(entry->path));
 350        hashmap_add(&o->current_file_dir_set, entry);
 351
 352        strbuf_setlen(base, baselen);
 353        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 354}
 355
 356static void get_files_dirs(struct merge_options *o, struct tree *tree)
 357{
 358        struct pathspec match_all;
 359        memset(&match_all, 0, sizeof(match_all));
 360        read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o);
 361}
 362
 363/*
 364 * Returns an index_entry instance which doesn't have to correspond to
 365 * a real cache entry in Git's index.
 366 */
 367static struct stage_data *insert_stage_data(const char *path,
 368                struct tree *o, struct tree *a, struct tree *b,
 369                struct string_list *entries)
 370{
 371        struct string_list_item *item;
 372        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 373        get_tree_entry(o->object.oid.hash, path,
 374                        e->stages[1].oid.hash, &e->stages[1].mode);
 375        get_tree_entry(a->object.oid.hash, path,
 376                        e->stages[2].oid.hash, &e->stages[2].mode);
 377        get_tree_entry(b->object.oid.hash, path,
 378                        e->stages[3].oid.hash, &e->stages[3].mode);
 379        item = string_list_insert(entries, path);
 380        item->util = e;
 381        return e;
 382}
 383
 384/*
 385 * Create a dictionary mapping file names to stage_data objects. The
 386 * dictionary contains one entry for every path with a non-zero stage entry.
 387 */
 388static struct string_list *get_unmerged(void)
 389{
 390        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 391        int i;
 392
 393        unmerged->strdup_strings = 1;
 394
 395        for (i = 0; i < active_nr; i++) {
 396                struct string_list_item *item;
 397                struct stage_data *e;
 398                const struct cache_entry *ce = active_cache[i];
 399                if (!ce_stage(ce))
 400                        continue;
 401
 402                item = string_list_lookup(unmerged, ce->name);
 403                if (!item) {
 404                        item = string_list_insert(unmerged, ce->name);
 405                        item->util = xcalloc(1, sizeof(struct stage_data));
 406                }
 407                e = item->util;
 408                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 409                oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
 410        }
 411
 412        return unmerged;
 413}
 414
 415static int string_list_df_name_compare(const char *one, const char *two)
 416{
 417        int onelen = strlen(one);
 418        int twolen = strlen(two);
 419        /*
 420         * Here we only care that entries for D/F conflicts are
 421         * adjacent, in particular with the file of the D/F conflict
 422         * appearing before files below the corresponding directory.
 423         * The order of the rest of the list is irrelevant for us.
 424         *
 425         * To achieve this, we sort with df_name_compare and provide
 426         * the mode S_IFDIR so that D/F conflicts will sort correctly.
 427         * We use the mode S_IFDIR for everything else for simplicity,
 428         * since in other cases any changes in their order due to
 429         * sorting cause no problems for us.
 430         */
 431        int cmp = df_name_compare(one, onelen, S_IFDIR,
 432                                  two, twolen, S_IFDIR);
 433        /*
 434         * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 435         * that 'foo' comes before 'foo/bar'.
 436         */
 437        if (cmp)
 438                return cmp;
 439        return onelen - twolen;
 440}
 441
 442static void record_df_conflict_files(struct merge_options *o,
 443                                     struct string_list *entries)
 444{
 445        /* If there is a D/F conflict and the file for such a conflict
 446         * currently exist in the working tree, we want to allow it to be
 447         * removed to make room for the corresponding directory if needed.
 448         * The files underneath the directories of such D/F conflicts will
 449         * be processed before the corresponding file involved in the D/F
 450         * conflict.  If the D/F directory ends up being removed by the
 451         * merge, then we won't have to touch the D/F file.  If the D/F
 452         * directory needs to be written to the working copy, then the D/F
 453         * file will simply be removed (in make_room_for_path()) to make
 454         * room for the necessary paths.  Note that if both the directory
 455         * and the file need to be present, then the D/F file will be
 456         * reinstated with a new unique name at the time it is processed.
 457         */
 458        struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
 459        const char *last_file = NULL;
 460        int last_len = 0;
 461        int i;
 462
 463        /*
 464         * If we're merging merge-bases, we don't want to bother with
 465         * any working directory changes.
 466         */
 467        if (o->call_depth)
 468                return;
 469
 470        /* Ensure D/F conflicts are adjacent in the entries list. */
 471        for (i = 0; i < entries->nr; i++) {
 472                struct string_list_item *next = &entries->items[i];
 473                string_list_append(&df_sorted_entries, next->string)->util =
 474                                   next->util;
 475        }
 476        df_sorted_entries.cmp = string_list_df_name_compare;
 477        string_list_sort(&df_sorted_entries);
 478
 479        string_list_clear(&o->df_conflict_file_set, 1);
 480        for (i = 0; i < df_sorted_entries.nr; i++) {
 481                const char *path = df_sorted_entries.items[i].string;
 482                int len = strlen(path);
 483                struct stage_data *e = df_sorted_entries.items[i].util;
 484
 485                /*
 486                 * Check if last_file & path correspond to a D/F conflict;
 487                 * i.e. whether path is last_file+'/'+<something>.
 488                 * If so, record that it's okay to remove last_file to make
 489                 * room for path and friends if needed.
 490                 */
 491                if (last_file &&
 492                    len > last_len &&
 493                    memcmp(path, last_file, last_len) == 0 &&
 494                    path[last_len] == '/') {
 495                        string_list_insert(&o->df_conflict_file_set, last_file);
 496                }
 497
 498                /*
 499                 * Determine whether path could exist as a file in the
 500                 * working directory as a possible D/F conflict.  This
 501                 * will only occur when it exists in stage 2 as a
 502                 * file.
 503                 */
 504                if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 505                        last_file = path;
 506                        last_len = len;
 507                } else {
 508                        last_file = NULL;
 509                }
 510        }
 511        string_list_clear(&df_sorted_entries, 0);
 512}
 513
 514struct rename {
 515        struct diff_filepair *pair;
 516        struct stage_data *src_entry;
 517        struct stage_data *dst_entry;
 518        unsigned processed:1;
 519};
 520
 521/*
 522 * Get information of all renames which occurred between 'o_tree' and
 523 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 524 * 'b_tree') to be able to associate the correct cache entries with
 525 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 526 */
 527static struct string_list *get_renames(struct merge_options *o,
 528                                       struct tree *tree,
 529                                       struct tree *o_tree,
 530                                       struct tree *a_tree,
 531                                       struct tree *b_tree,
 532                                       struct string_list *entries)
 533{
 534        int i;
 535        struct string_list *renames;
 536        struct diff_options opts;
 537
 538        renames = xcalloc(1, sizeof(struct string_list));
 539        if (!o->detect_rename)
 540                return renames;
 541
 542        diff_setup(&opts);
 543        opts.flags.recursive = 1;
 544        opts.flags.rename_empty = 0;
 545        opts.detect_rename = DIFF_DETECT_RENAME;
 546        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 547                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 548                            1000;
 549        opts.rename_score = o->rename_score;
 550        opts.show_rename_progress = o->show_rename_progress;
 551        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 552        diff_setup_done(&opts);
 553        diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
 554        diffcore_std(&opts);
 555        if (opts.needed_rename_limit > o->needed_rename_limit)
 556                o->needed_rename_limit = opts.needed_rename_limit;
 557        for (i = 0; i < diff_queued_diff.nr; ++i) {
 558                struct string_list_item *item;
 559                struct rename *re;
 560                struct diff_filepair *pair = diff_queued_diff.queue[i];
 561                if (pair->status != 'R') {
 562                        diff_free_filepair(pair);
 563                        continue;
 564                }
 565                re = xmalloc(sizeof(*re));
 566                re->processed = 0;
 567                re->pair = pair;
 568                item = string_list_lookup(entries, re->pair->one->path);
 569                if (!item)
 570                        re->src_entry = insert_stage_data(re->pair->one->path,
 571                                        o_tree, a_tree, b_tree, entries);
 572                else
 573                        re->src_entry = item->util;
 574
 575                item = string_list_lookup(entries, re->pair->two->path);
 576                if (!item)
 577                        re->dst_entry = insert_stage_data(re->pair->two->path,
 578                                        o_tree, a_tree, b_tree, entries);
 579                else
 580                        re->dst_entry = item->util;
 581                item = string_list_insert(renames, pair->one->path);
 582                item->util = re;
 583        }
 584        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 585        diff_queued_diff.nr = 0;
 586        diff_flush(&opts);
 587        return renames;
 588}
 589
 590static int update_stages(struct merge_options *opt, const char *path,
 591                         const struct diff_filespec *o,
 592                         const struct diff_filespec *a,
 593                         const struct diff_filespec *b)
 594{
 595
 596        /*
 597         * NOTE: It is usually a bad idea to call update_stages on a path
 598         * before calling update_file on that same path, since it can
 599         * sometimes lead to spurious "refusing to lose untracked file..."
 600         * messages from update_file (via make_room_for path via
 601         * would_lose_untracked).  Instead, reverse the order of the calls
 602         * (executing update_file first and then update_stages).
 603         */
 604        int clear = 1;
 605        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 606        if (clear)
 607                if (remove_file_from_cache(path))
 608                        return -1;
 609        if (o)
 610                if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
 611                        return -1;
 612        if (a)
 613                if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
 614                        return -1;
 615        if (b)
 616                if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
 617                        return -1;
 618        return 0;
 619}
 620
 621static void update_entry(struct stage_data *entry,
 622                         struct diff_filespec *o,
 623                         struct diff_filespec *a,
 624                         struct diff_filespec *b)
 625{
 626        entry->processed = 0;
 627        entry->stages[1].mode = o->mode;
 628        entry->stages[2].mode = a->mode;
 629        entry->stages[3].mode = b->mode;
 630        oidcpy(&entry->stages[1].oid, &o->oid);
 631        oidcpy(&entry->stages[2].oid, &a->oid);
 632        oidcpy(&entry->stages[3].oid, &b->oid);
 633}
 634
 635static int remove_file(struct merge_options *o, int clean,
 636                       const char *path, int no_wd)
 637{
 638        int update_cache = o->call_depth || clean;
 639        int update_working_directory = !o->call_depth && !no_wd;
 640
 641        if (update_cache) {
 642                if (remove_file_from_cache(path))
 643                        return -1;
 644        }
 645        if (update_working_directory) {
 646                if (ignore_case) {
 647                        struct cache_entry *ce;
 648                        ce = cache_file_exists(path, strlen(path), ignore_case);
 649                        if (ce && ce_stage(ce) == 0)
 650                                return 0;
 651                }
 652                if (remove_path(path))
 653                        return -1;
 654        }
 655        return 0;
 656}
 657
 658/* add a string to a strbuf, but converting "/" to "_" */
 659static void add_flattened_path(struct strbuf *out, const char *s)
 660{
 661        size_t i = out->len;
 662        strbuf_addstr(out, s);
 663        for (; i < out->len; i++)
 664                if (out->buf[i] == '/')
 665                        out->buf[i] = '_';
 666}
 667
 668static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 669{
 670        struct path_hashmap_entry *entry;
 671        struct strbuf newpath = STRBUF_INIT;
 672        int suffix = 0;
 673        size_t base_len;
 674
 675        strbuf_addf(&newpath, "%s~", path);
 676        add_flattened_path(&newpath, branch);
 677
 678        base_len = newpath.len;
 679        while (hashmap_get_from_hash(&o->current_file_dir_set,
 680                                     path_hash(newpath.buf), newpath.buf) ||
 681               (!o->call_depth && file_exists(newpath.buf))) {
 682                strbuf_setlen(&newpath, base_len);
 683                strbuf_addf(&newpath, "_%d", suffix++);
 684        }
 685
 686        FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
 687        hashmap_entry_init(entry, path_hash(entry->path));
 688        hashmap_add(&o->current_file_dir_set, entry);
 689        return strbuf_detach(&newpath, NULL);
 690}
 691
 692/**
 693 * Check whether a directory in the index is in the way of an incoming
 694 * file.  Return 1 if so.  If check_working_copy is non-zero, also
 695 * check the working directory.  If empty_ok is non-zero, also return
 696 * 0 in the case where the working-tree dir exists but is empty.
 697 */
 698static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
 699{
 700        int pos;
 701        struct strbuf dirpath = STRBUF_INIT;
 702        struct stat st;
 703
 704        strbuf_addstr(&dirpath, path);
 705        strbuf_addch(&dirpath, '/');
 706
 707        pos = cache_name_pos(dirpath.buf, dirpath.len);
 708
 709        if (pos < 0)
 710                pos = -1 - pos;
 711        if (pos < active_nr &&
 712            !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
 713                strbuf_release(&dirpath);
 714                return 1;
 715        }
 716
 717        strbuf_release(&dirpath);
 718        return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
 719                !(empty_ok && is_empty_dir(path));
 720}
 721
 722static int was_tracked(const char *path)
 723{
 724        int pos = cache_name_pos(path, strlen(path));
 725
 726        if (0 <= pos)
 727                /* we have been tracking this path */
 728                return 1;
 729
 730        /*
 731         * Look for an unmerged entry for the path,
 732         * specifically stage #2, which would indicate
 733         * that "our" side before the merge started
 734         * had the path tracked (and resulted in a conflict).
 735         */
 736        for (pos = -1 - pos;
 737             pos < active_nr && !strcmp(path, active_cache[pos]->name);
 738             pos++)
 739                if (ce_stage(active_cache[pos]) == 2)
 740                        return 1;
 741        return 0;
 742}
 743
 744static int would_lose_untracked(const char *path)
 745{
 746        return !was_tracked(path) && file_exists(path);
 747}
 748
 749static int make_room_for_path(struct merge_options *o, const char *path)
 750{
 751        int status, i;
 752        const char *msg = _("failed to create path '%s'%s");
 753
 754        /* Unlink any D/F conflict files that are in the way */
 755        for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 756                const char *df_path = o->df_conflict_file_set.items[i].string;
 757                size_t pathlen = strlen(path);
 758                size_t df_pathlen = strlen(df_path);
 759                if (df_pathlen < pathlen &&
 760                    path[df_pathlen] == '/' &&
 761                    strncmp(path, df_path, df_pathlen) == 0) {
 762                        output(o, 3,
 763                               _("Removing %s to make room for subdirectory\n"),
 764                               df_path);
 765                        unlink(df_path);
 766                        unsorted_string_list_delete_item(&o->df_conflict_file_set,
 767                                                         i, 0);
 768                        break;
 769                }
 770        }
 771
 772        /* Make sure leading directories are created */
 773        status = safe_create_leading_directories_const(path);
 774        if (status) {
 775                if (status == SCLD_EXISTS)
 776                        /* something else exists */
 777                        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 778                return err(o, msg, path, "");
 779        }
 780
 781        /*
 782         * Do not unlink a file in the work tree if we are not
 783         * tracking it.
 784         */
 785        if (would_lose_untracked(path))
 786                return err(o, _("refusing to lose untracked file at '%s'"),
 787                             path);
 788
 789        /* Successful unlink is good.. */
 790        if (!unlink(path))
 791                return 0;
 792        /* .. and so is no existing file */
 793        if (errno == ENOENT)
 794                return 0;
 795        /* .. but not some other error (who really cares what?) */
 796        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 797}
 798
 799static int update_file_flags(struct merge_options *o,
 800                             const struct object_id *oid,
 801                             unsigned mode,
 802                             const char *path,
 803                             int update_cache,
 804                             int update_wd)
 805{
 806        int ret = 0;
 807
 808        if (o->call_depth)
 809                update_wd = 0;
 810
 811        if (update_wd) {
 812                enum object_type type;
 813                void *buf;
 814                unsigned long size;
 815
 816                if (S_ISGITLINK(mode)) {
 817                        /*
 818                         * We may later decide to recursively descend into
 819                         * the submodule directory and update its index
 820                         * and/or work tree, but we do not do that now.
 821                         */
 822                        update_wd = 0;
 823                        goto update_index;
 824                }
 825
 826                buf = read_sha1_file(oid->hash, &type, &size);
 827                if (!buf)
 828                        return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 829                if (type != OBJ_BLOB) {
 830                        ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 831                        goto free_buf;
 832                }
 833                if (S_ISREG(mode)) {
 834                        struct strbuf strbuf = STRBUF_INIT;
 835                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 836                                free(buf);
 837                                size = strbuf.len;
 838                                buf = strbuf_detach(&strbuf, NULL);
 839                        }
 840                }
 841
 842                if (make_room_for_path(o, path) < 0) {
 843                        update_wd = 0;
 844                        goto free_buf;
 845                }
 846                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 847                        int fd;
 848                        if (mode & 0100)
 849                                mode = 0777;
 850                        else
 851                                mode = 0666;
 852                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 853                        if (fd < 0) {
 854                                ret = err(o, _("failed to open '%s': %s"),
 855                                          path, strerror(errno));
 856                                goto free_buf;
 857                        }
 858                        write_in_full(fd, buf, size);
 859                        close(fd);
 860                } else if (S_ISLNK(mode)) {
 861                        char *lnk = xmemdupz(buf, size);
 862                        safe_create_leading_directories_const(path);
 863                        unlink(path);
 864                        if (symlink(lnk, path))
 865                                ret = err(o, _("failed to symlink '%s': %s"),
 866                                        path, strerror(errno));
 867                        free(lnk);
 868                } else
 869                        ret = err(o,
 870                                  _("do not know what to do with %06o %s '%s'"),
 871                                  mode, oid_to_hex(oid), path);
 872 free_buf:
 873                free(buf);
 874        }
 875 update_index:
 876        if (!ret && update_cache)
 877                add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 878        return ret;
 879}
 880
 881static int update_file(struct merge_options *o,
 882                       int clean,
 883                       const struct object_id *oid,
 884                       unsigned mode,
 885                       const char *path)
 886{
 887        return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
 888}
 889
 890/* Low level file merging, update and removal */
 891
 892struct merge_file_info {
 893        struct object_id oid;
 894        unsigned mode;
 895        unsigned clean:1,
 896                 merge:1;
 897};
 898
 899static int merge_3way(struct merge_options *o,
 900                      mmbuffer_t *result_buf,
 901                      const struct diff_filespec *one,
 902                      const struct diff_filespec *a,
 903                      const struct diff_filespec *b,
 904                      const char *branch1,
 905                      const char *branch2)
 906{
 907        mmfile_t orig, src1, src2;
 908        struct ll_merge_options ll_opts = {0};
 909        char *base_name, *name1, *name2;
 910        int merge_status;
 911
 912        ll_opts.renormalize = o->renormalize;
 913        ll_opts.xdl_opts = o->xdl_opts;
 914
 915        if (o->call_depth) {
 916                ll_opts.virtual_ancestor = 1;
 917                ll_opts.variant = 0;
 918        } else {
 919                switch (o->recursive_variant) {
 920                case MERGE_RECURSIVE_OURS:
 921                        ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 922                        break;
 923                case MERGE_RECURSIVE_THEIRS:
 924                        ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 925                        break;
 926                default:
 927                        ll_opts.variant = 0;
 928                        break;
 929                }
 930        }
 931
 932        if (strcmp(a->path, b->path) ||
 933            (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 934                base_name = o->ancestor == NULL ? NULL :
 935                        mkpathdup("%s:%s", o->ancestor, one->path);
 936                name1 = mkpathdup("%s:%s", branch1, a->path);
 937                name2 = mkpathdup("%s:%s", branch2, b->path);
 938        } else {
 939                base_name = o->ancestor == NULL ? NULL :
 940                        mkpathdup("%s", o->ancestor);
 941                name1 = mkpathdup("%s", branch1);
 942                name2 = mkpathdup("%s", branch2);
 943        }
 944
 945        read_mmblob(&orig, &one->oid);
 946        read_mmblob(&src1, &a->oid);
 947        read_mmblob(&src2, &b->oid);
 948
 949        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 950                                &src1, name1, &src2, name2, &ll_opts);
 951
 952        free(base_name);
 953        free(name1);
 954        free(name2);
 955        free(orig.ptr);
 956        free(src1.ptr);
 957        free(src2.ptr);
 958        return merge_status;
 959}
 960
 961static int merge_file_1(struct merge_options *o,
 962                                           const struct diff_filespec *one,
 963                                           const struct diff_filespec *a,
 964                                           const struct diff_filespec *b,
 965                                           const char *branch1,
 966                                           const char *branch2,
 967                                           struct merge_file_info *result)
 968{
 969        result->merge = 0;
 970        result->clean = 1;
 971
 972        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 973                result->clean = 0;
 974                if (S_ISREG(a->mode)) {
 975                        result->mode = a->mode;
 976                        oidcpy(&result->oid, &a->oid);
 977                } else {
 978                        result->mode = b->mode;
 979                        oidcpy(&result->oid, &b->oid);
 980                }
 981        } else {
 982                if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
 983                        result->merge = 1;
 984
 985                /*
 986                 * Merge modes
 987                 */
 988                if (a->mode == b->mode || a->mode == one->mode)
 989                        result->mode = b->mode;
 990                else {
 991                        result->mode = a->mode;
 992                        if (b->mode != one->mode) {
 993                                result->clean = 0;
 994                                result->merge = 1;
 995                        }
 996                }
 997
 998                if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
 999                        oidcpy(&result->oid, &b->oid);
1000                else if (oid_eq(&b->oid, &one->oid))
1001                        oidcpy(&result->oid, &a->oid);
1002                else if (S_ISREG(a->mode)) {
1003                        mmbuffer_t result_buf;
1004                        int ret = 0, merge_status;
1005
1006                        merge_status = merge_3way(o, &result_buf, one, a, b,
1007                                                  branch1, branch2);
1008
1009                        if ((merge_status < 0) || !result_buf.ptr)
1010                                ret = err(o, _("Failed to execute internal merge"));
1011
1012                        if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
1013                                                    blob_type, result->oid.hash))
1014                                ret = err(o, _("Unable to add %s to database"),
1015                                          a->path);
1016
1017                        free(result_buf.ptr);
1018                        if (ret)
1019                                return ret;
1020                        result->clean = (merge_status == 0);
1021                } else if (S_ISGITLINK(a->mode)) {
1022                        result->clean = merge_submodule(&result->oid,
1023                                                       one->path,
1024                                                       &one->oid,
1025                                                       &a->oid,
1026                                                       &b->oid,
1027                                                       !o->call_depth);
1028                } else if (S_ISLNK(a->mode)) {
1029                        oidcpy(&result->oid, &a->oid);
1030
1031                        if (!oid_eq(&a->oid, &b->oid))
1032                                result->clean = 0;
1033                } else
1034                        die("BUG: unsupported object type in the tree");
1035        }
1036
1037        return 0;
1038}
1039
1040static int merge_file_special_markers(struct merge_options *o,
1041                           const struct diff_filespec *one,
1042                           const struct diff_filespec *a,
1043                           const struct diff_filespec *b,
1044                           const char *branch1,
1045                           const char *filename1,
1046                           const char *branch2,
1047                           const char *filename2,
1048                           struct merge_file_info *mfi)
1049{
1050        char *side1 = NULL;
1051        char *side2 = NULL;
1052        int ret;
1053
1054        if (filename1)
1055                side1 = xstrfmt("%s:%s", branch1, filename1);
1056        if (filename2)
1057                side2 = xstrfmt("%s:%s", branch2, filename2);
1058
1059        ret = merge_file_1(o, one, a, b,
1060                           side1 ? side1 : branch1,
1061                           side2 ? side2 : branch2, mfi);
1062        free(side1);
1063        free(side2);
1064        return ret;
1065}
1066
1067static int merge_file_one(struct merge_options *o,
1068                                         const char *path,
1069                                         const struct object_id *o_oid, int o_mode,
1070                                         const struct object_id *a_oid, int a_mode,
1071                                         const struct object_id *b_oid, int b_mode,
1072                                         const char *branch1,
1073                                         const char *branch2,
1074                                         struct merge_file_info *mfi)
1075{
1076        struct diff_filespec one, a, b;
1077
1078        one.path = a.path = b.path = (char *)path;
1079        oidcpy(&one.oid, o_oid);
1080        one.mode = o_mode;
1081        oidcpy(&a.oid, a_oid);
1082        a.mode = a_mode;
1083        oidcpy(&b.oid, b_oid);
1084        b.mode = b_mode;
1085        return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
1086}
1087
1088static int handle_change_delete(struct merge_options *o,
1089                                 const char *path, const char *old_path,
1090                                 const struct object_id *o_oid, int o_mode,
1091                                 const struct object_id *changed_oid,
1092                                 int changed_mode,
1093                                 const char *change_branch,
1094                                 const char *delete_branch,
1095                                 const char *change, const char *change_past)
1096{
1097        char *alt_path = NULL;
1098        const char *update_path = path;
1099        int ret = 0;
1100
1101        if (dir_in_way(path, !o->call_depth, 0)) {
1102                update_path = alt_path = unique_path(o, path, change_branch);
1103        }
1104
1105        if (o->call_depth) {
1106                /*
1107                 * We cannot arbitrarily accept either a_sha or b_sha as
1108                 * correct; since there is no true "middle point" between
1109                 * them, simply reuse the base version for virtual merge base.
1110                 */
1111                ret = remove_file_from_cache(path);
1112                if (!ret)
1113                        ret = update_file(o, 0, o_oid, o_mode, update_path);
1114        } else {
1115                if (!alt_path) {
1116                        if (!old_path) {
1117                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1118                                       "and %s in %s. Version %s of %s left in tree."),
1119                                       change, path, delete_branch, change_past,
1120                                       change_branch, change_branch, path);
1121                        } else {
1122                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1123                                       "and %s to %s in %s. Version %s of %s left in tree."),
1124                                       change, old_path, delete_branch, change_past, path,
1125                                       change_branch, change_branch, path);
1126                        }
1127                } else {
1128                        if (!old_path) {
1129                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1130                                       "and %s in %s. Version %s of %s left in tree at %s."),
1131                                       change, path, delete_branch, change_past,
1132                                       change_branch, change_branch, path, alt_path);
1133                        } else {
1134                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1135                                       "and %s to %s in %s. Version %s of %s left in tree at %s."),
1136                                       change, old_path, delete_branch, change_past, path,
1137                                       change_branch, change_branch, path, alt_path);
1138                        }
1139                }
1140                /*
1141                 * No need to call update_file() on path when change_branch ==
1142                 * o->branch1 && !alt_path, since that would needlessly touch
1143                 * path.  We could call update_file_flags() with update_cache=0
1144                 * and update_wd=0, but that's a no-op.
1145                 */
1146                if (change_branch != o->branch1 || alt_path)
1147                        ret = update_file(o, 0, changed_oid, changed_mode, update_path);
1148        }
1149        free(alt_path);
1150
1151        return ret;
1152}
1153
1154static int conflict_rename_delete(struct merge_options *o,
1155                                   struct diff_filepair *pair,
1156                                   const char *rename_branch,
1157                                   const char *delete_branch)
1158{
1159        const struct diff_filespec *orig = pair->one;
1160        const struct diff_filespec *dest = pair->two;
1161
1162        if (handle_change_delete(o,
1163                                 o->call_depth ? orig->path : dest->path,
1164                                 o->call_depth ? NULL : orig->path,
1165                                 &orig->oid, orig->mode,
1166                                 &dest->oid, dest->mode,
1167                                 rename_branch, delete_branch,
1168                                 _("rename"), _("renamed")))
1169                return -1;
1170
1171        if (o->call_depth)
1172                return remove_file_from_cache(dest->path);
1173        else
1174                return update_stages(o, dest->path, NULL,
1175                                     rename_branch == o->branch1 ? dest : NULL,
1176                                     rename_branch == o->branch1 ? NULL : dest);
1177}
1178
1179static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1180                                                 struct stage_data *entry,
1181                                                 int stage)
1182{
1183        struct object_id *oid = &entry->stages[stage].oid;
1184        unsigned mode = entry->stages[stage].mode;
1185        if (mode == 0 || is_null_oid(oid))
1186                return NULL;
1187        oidcpy(&target->oid, oid);
1188        target->mode = mode;
1189        return target;
1190}
1191
1192static int handle_file(struct merge_options *o,
1193                        struct diff_filespec *rename,
1194                        int stage,
1195                        struct rename_conflict_info *ci)
1196{
1197        char *dst_name = rename->path;
1198        struct stage_data *dst_entry;
1199        const char *cur_branch, *other_branch;
1200        struct diff_filespec other;
1201        struct diff_filespec *add;
1202        int ret;
1203
1204        if (stage == 2) {
1205                dst_entry = ci->dst_entry1;
1206                cur_branch = ci->branch1;
1207                other_branch = ci->branch2;
1208        } else {
1209                dst_entry = ci->dst_entry2;
1210                cur_branch = ci->branch2;
1211                other_branch = ci->branch1;
1212        }
1213
1214        add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1215        if (add) {
1216                char *add_name = unique_path(o, rename->path, other_branch);
1217                if (update_file(o, 0, &add->oid, add->mode, add_name))
1218                        return -1;
1219
1220                remove_file(o, 0, rename->path, 0);
1221                dst_name = unique_path(o, rename->path, cur_branch);
1222        } else {
1223                if (dir_in_way(rename->path, !o->call_depth, 0)) {
1224                        dst_name = unique_path(o, rename->path, cur_branch);
1225                        output(o, 1, _("%s is a directory in %s adding as %s instead"),
1226                               rename->path, other_branch, dst_name);
1227                }
1228        }
1229        if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
1230                ; /* fall through, do allow dst_name to be released */
1231        else if (stage == 2)
1232                ret = update_stages(o, rename->path, NULL, rename, add);
1233        else
1234                ret = update_stages(o, rename->path, NULL, add, rename);
1235
1236        if (dst_name != rename->path)
1237                free(dst_name);
1238
1239        return ret;
1240}
1241
1242static int conflict_rename_rename_1to2(struct merge_options *o,
1243                                        struct rename_conflict_info *ci)
1244{
1245        /* One file was renamed in both branches, but to different names. */
1246        struct diff_filespec *one = ci->pair1->one;
1247        struct diff_filespec *a = ci->pair1->two;
1248        struct diff_filespec *b = ci->pair2->two;
1249
1250        output(o, 1, _("CONFLICT (rename/rename): "
1251               "Rename \"%s\"->\"%s\" in branch \"%s\" "
1252               "rename \"%s\"->\"%s\" in \"%s\"%s"),
1253               one->path, a->path, ci->branch1,
1254               one->path, b->path, ci->branch2,
1255               o->call_depth ? _(" (left unresolved)") : "");
1256        if (o->call_depth) {
1257                struct merge_file_info mfi;
1258                struct diff_filespec other;
1259                struct diff_filespec *add;
1260                if (merge_file_one(o, one->path,
1261                                 &one->oid, one->mode,
1262                                 &a->oid, a->mode,
1263                                 &b->oid, b->mode,
1264                                 ci->branch1, ci->branch2, &mfi))
1265                        return -1;
1266
1267                /*
1268                 * FIXME: For rename/add-source conflicts (if we could detect
1269                 * such), this is wrong.  We should instead find a unique
1270                 * pathname and then either rename the add-source file to that
1271                 * unique path, or use that unique path instead of src here.
1272                 */
1273                if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
1274                        return -1;
1275
1276                /*
1277                 * Above, we put the merged content at the merge-base's
1278                 * path.  Now we usually need to delete both a->path and
1279                 * b->path.  However, the rename on each side of the merge
1280                 * could also be involved in a rename/add conflict.  In
1281                 * such cases, we should keep the added file around,
1282                 * resolving the conflict at that path in its favor.
1283                 */
1284                add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1285                if (add) {
1286                        if (update_file(o, 0, &add->oid, add->mode, a->path))
1287                                return -1;
1288                }
1289                else
1290                        remove_file_from_cache(a->path);
1291                add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1292                if (add) {
1293                        if (update_file(o, 0, &add->oid, add->mode, b->path))
1294                                return -1;
1295                }
1296                else
1297                        remove_file_from_cache(b->path);
1298        } else if (handle_file(o, a, 2, ci) || handle_file(o, b, 3, ci))
1299                return -1;
1300
1301        return 0;
1302}
1303
1304static int conflict_rename_rename_2to1(struct merge_options *o,
1305                                        struct rename_conflict_info *ci)
1306{
1307        /* Two files, a & b, were renamed to the same thing, c. */
1308        struct diff_filespec *a = ci->pair1->one;
1309        struct diff_filespec *b = ci->pair2->one;
1310        struct diff_filespec *c1 = ci->pair1->two;
1311        struct diff_filespec *c2 = ci->pair2->two;
1312        char *path = c1->path; /* == c2->path */
1313        struct merge_file_info mfi_c1;
1314        struct merge_file_info mfi_c2;
1315        int ret;
1316
1317        output(o, 1, _("CONFLICT (rename/rename): "
1318               "Rename %s->%s in %s. "
1319               "Rename %s->%s in %s"),
1320               a->path, c1->path, ci->branch1,
1321               b->path, c2->path, ci->branch2);
1322
1323        remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1324        remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1325
1326        if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
1327                                       o->branch1, c1->path,
1328                                       o->branch2, ci->ren1_other.path, &mfi_c1) ||
1329            merge_file_special_markers(o, b, &ci->ren2_other, c2,
1330                                       o->branch1, ci->ren2_other.path,
1331                                       o->branch2, c2->path, &mfi_c2))
1332                return -1;
1333
1334        if (o->call_depth) {
1335                /*
1336                 * If mfi_c1.clean && mfi_c2.clean, then it might make
1337                 * sense to do a two-way merge of those results.  But, I
1338                 * think in all cases, it makes sense to have the virtual
1339                 * merge base just undo the renames; they can be detected
1340                 * again later for the non-recursive merge.
1341                 */
1342                remove_file(o, 0, path, 0);
1343                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, a->path);
1344                if (!ret)
1345                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1346                                          b->path);
1347        } else {
1348                char *new_path1 = unique_path(o, path, ci->branch1);
1349                char *new_path2 = unique_path(o, path, ci->branch2);
1350                output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1351                       a->path, new_path1, b->path, new_path2);
1352                remove_file(o, 0, path, 0);
1353                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
1354                if (!ret)
1355                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1356                                          new_path2);
1357                free(new_path2);
1358                free(new_path1);
1359        }
1360
1361        return ret;
1362}
1363
1364static int process_renames(struct merge_options *o,
1365                           struct string_list *a_renames,
1366                           struct string_list *b_renames)
1367{
1368        int clean_merge = 1, i, j;
1369        struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1370        struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1371        const struct rename *sre;
1372
1373        for (i = 0; i < a_renames->nr; i++) {
1374                sre = a_renames->items[i].util;
1375                string_list_insert(&a_by_dst, sre->pair->two->path)->util
1376                        = (void *)sre;
1377        }
1378        for (i = 0; i < b_renames->nr; i++) {
1379                sre = b_renames->items[i].util;
1380                string_list_insert(&b_by_dst, sre->pair->two->path)->util
1381                        = (void *)sre;
1382        }
1383
1384        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1385                struct string_list *renames1, *renames2Dst;
1386                struct rename *ren1 = NULL, *ren2 = NULL;
1387                const char *branch1, *branch2;
1388                const char *ren1_src, *ren1_dst;
1389                struct string_list_item *lookup;
1390
1391                if (i >= a_renames->nr) {
1392                        ren2 = b_renames->items[j++].util;
1393                } else if (j >= b_renames->nr) {
1394                        ren1 = a_renames->items[i++].util;
1395                } else {
1396                        int compare = strcmp(a_renames->items[i].string,
1397                                             b_renames->items[j].string);
1398                        if (compare <= 0)
1399                                ren1 = a_renames->items[i++].util;
1400                        if (compare >= 0)
1401                                ren2 = b_renames->items[j++].util;
1402                }
1403
1404                /* TODO: refactor, so that 1/2 are not needed */
1405                if (ren1) {
1406                        renames1 = a_renames;
1407                        renames2Dst = &b_by_dst;
1408                        branch1 = o->branch1;
1409                        branch2 = o->branch2;
1410                } else {
1411                        renames1 = b_renames;
1412                        renames2Dst = &a_by_dst;
1413                        branch1 = o->branch2;
1414                        branch2 = o->branch1;
1415                        SWAP(ren2, ren1);
1416                }
1417
1418                if (ren1->processed)
1419                        continue;
1420                ren1->processed = 1;
1421                ren1->dst_entry->processed = 1;
1422                /* BUG: We should only mark src_entry as processed if we
1423                 * are not dealing with a rename + add-source case.
1424                 */
1425                ren1->src_entry->processed = 1;
1426
1427                ren1_src = ren1->pair->one->path;
1428                ren1_dst = ren1->pair->two->path;
1429
1430                if (ren2) {
1431                        /* One file renamed on both sides */
1432                        const char *ren2_src = ren2->pair->one->path;
1433                        const char *ren2_dst = ren2->pair->two->path;
1434                        enum rename_type rename_type;
1435                        if (strcmp(ren1_src, ren2_src) != 0)
1436                                die("BUG: ren1_src != ren2_src");
1437                        ren2->dst_entry->processed = 1;
1438                        ren2->processed = 1;
1439                        if (strcmp(ren1_dst, ren2_dst) != 0) {
1440                                rename_type = RENAME_ONE_FILE_TO_TWO;
1441                                clean_merge = 0;
1442                        } else {
1443                                rename_type = RENAME_ONE_FILE_TO_ONE;
1444                                /* BUG: We should only remove ren1_src in
1445                                 * the base stage (think of rename +
1446                                 * add-source cases).
1447                                 */
1448                                remove_file(o, 1, ren1_src, 1);
1449                                update_entry(ren1->dst_entry,
1450                                             ren1->pair->one,
1451                                             ren1->pair->two,
1452                                             ren2->pair->two);
1453                        }
1454                        setup_rename_conflict_info(rename_type,
1455                                                   ren1->pair,
1456                                                   ren2->pair,
1457                                                   branch1,
1458                                                   branch2,
1459                                                   ren1->dst_entry,
1460                                                   ren2->dst_entry,
1461                                                   o,
1462                                                   NULL,
1463                                                   NULL);
1464                } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1465                        /* Two different files renamed to the same thing */
1466                        char *ren2_dst;
1467                        ren2 = lookup->util;
1468                        ren2_dst = ren2->pair->two->path;
1469                        if (strcmp(ren1_dst, ren2_dst) != 0)
1470                                die("BUG: ren1_dst != ren2_dst");
1471
1472                        clean_merge = 0;
1473                        ren2->processed = 1;
1474                        /*
1475                         * BUG: We should only mark src_entry as processed
1476                         * if we are not dealing with a rename + add-source
1477                         * case.
1478                         */
1479                        ren2->src_entry->processed = 1;
1480
1481                        setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1482                                                   ren1->pair,
1483                                                   ren2->pair,
1484                                                   branch1,
1485                                                   branch2,
1486                                                   ren1->dst_entry,
1487                                                   ren2->dst_entry,
1488                                                   o,
1489                                                   ren1->src_entry,
1490                                                   ren2->src_entry);
1491
1492                } else {
1493                        /* Renamed in 1, maybe changed in 2 */
1494                        /* we only use sha1 and mode of these */
1495                        struct diff_filespec src_other, dst_other;
1496                        int try_merge;
1497
1498                        /*
1499                         * unpack_trees loads entries from common-commit
1500                         * into stage 1, from head-commit into stage 2, and
1501                         * from merge-commit into stage 3.  We keep track
1502                         * of which side corresponds to the rename.
1503                         */
1504                        int renamed_stage = a_renames == renames1 ? 2 : 3;
1505                        int other_stage =   a_renames == renames1 ? 3 : 2;
1506
1507                        /* BUG: We should only remove ren1_src in the base
1508                         * stage and in other_stage (think of rename +
1509                         * add-source case).
1510                         */
1511                        remove_file(o, 1, ren1_src,
1512                                    renamed_stage == 2 || !was_tracked(ren1_src));
1513
1514                        oidcpy(&src_other.oid,
1515                               &ren1->src_entry->stages[other_stage].oid);
1516                        src_other.mode = ren1->src_entry->stages[other_stage].mode;
1517                        oidcpy(&dst_other.oid,
1518                               &ren1->dst_entry->stages[other_stage].oid);
1519                        dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1520                        try_merge = 0;
1521
1522                        if (oid_eq(&src_other.oid, &null_oid)) {
1523                                setup_rename_conflict_info(RENAME_DELETE,
1524                                                           ren1->pair,
1525                                                           NULL,
1526                                                           branch1,
1527                                                           branch2,
1528                                                           ren1->dst_entry,
1529                                                           NULL,
1530                                                           o,
1531                                                           NULL,
1532                                                           NULL);
1533                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
1534                                   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
1535                                /*
1536                                 * Added file on the other side identical to
1537                                 * the file being renamed: clean merge.
1538                                 * Also, there is no need to overwrite the
1539                                 * file already in the working copy, so call
1540                                 * update_file_flags() instead of
1541                                 * update_file().
1542                                 */
1543                                if (update_file_flags(o,
1544                                                      &ren1->pair->two->oid,
1545                                                      ren1->pair->two->mode,
1546                                                      ren1_dst,
1547                                                      1, /* update_cache */
1548                                                      0  /* update_wd    */))
1549                                        clean_merge = -1;
1550                        } else if (!oid_eq(&dst_other.oid, &null_oid)) {
1551                                clean_merge = 0;
1552                                try_merge = 1;
1553                                output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1554                                       "%s added in %s"),
1555                                       ren1_src, ren1_dst, branch1,
1556                                       ren1_dst, branch2);
1557                                if (o->call_depth) {
1558                                        struct merge_file_info mfi;
1559                                        if (merge_file_one(o, ren1_dst, &null_oid, 0,
1560                                                           &ren1->pair->two->oid,
1561                                                           ren1->pair->two->mode,
1562                                                           &dst_other.oid,
1563                                                           dst_other.mode,
1564                                                           branch1, branch2, &mfi)) {
1565                                                clean_merge = -1;
1566                                                goto cleanup_and_return;
1567                                        }
1568                                        output(o, 1, _("Adding merged %s"), ren1_dst);
1569                                        if (update_file(o, 0, &mfi.oid,
1570                                                        mfi.mode, ren1_dst))
1571                                                clean_merge = -1;
1572                                        try_merge = 0;
1573                                } else {
1574                                        char *new_path = unique_path(o, ren1_dst, branch2);
1575                                        output(o, 1, _("Adding as %s instead"), new_path);
1576                                        if (update_file(o, 0, &dst_other.oid,
1577                                                        dst_other.mode, new_path))
1578                                                clean_merge = -1;
1579                                        free(new_path);
1580                                }
1581                        } else
1582                                try_merge = 1;
1583
1584                        if (clean_merge < 0)
1585                                goto cleanup_and_return;
1586                        if (try_merge) {
1587                                struct diff_filespec *one, *a, *b;
1588                                src_other.path = (char *)ren1_src;
1589
1590                                one = ren1->pair->one;
1591                                if (a_renames == renames1) {
1592                                        a = ren1->pair->two;
1593                                        b = &src_other;
1594                                } else {
1595                                        b = ren1->pair->two;
1596                                        a = &src_other;
1597                                }
1598                                update_entry(ren1->dst_entry, one, a, b);
1599                                setup_rename_conflict_info(RENAME_NORMAL,
1600                                                           ren1->pair,
1601                                                           NULL,
1602                                                           branch1,
1603                                                           NULL,
1604                                                           ren1->dst_entry,
1605                                                           NULL,
1606                                                           o,
1607                                                           NULL,
1608                                                           NULL);
1609                        }
1610                }
1611        }
1612cleanup_and_return:
1613        string_list_clear(&a_by_dst, 0);
1614        string_list_clear(&b_by_dst, 0);
1615
1616        return clean_merge;
1617}
1618
1619static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
1620{
1621        return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
1622}
1623
1624static int read_oid_strbuf(struct merge_options *o,
1625        const struct object_id *oid, struct strbuf *dst)
1626{
1627        void *buf;
1628        enum object_type type;
1629        unsigned long size;
1630        buf = read_sha1_file(oid->hash, &type, &size);
1631        if (!buf)
1632                return err(o, _("cannot read object %s"), oid_to_hex(oid));
1633        if (type != OBJ_BLOB) {
1634                free(buf);
1635                return err(o, _("object %s is not a blob"), oid_to_hex(oid));
1636        }
1637        strbuf_attach(dst, buf, size, size + 1);
1638        return 0;
1639}
1640
1641static int blob_unchanged(struct merge_options *opt,
1642                          const struct object_id *o_oid,
1643                          unsigned o_mode,
1644                          const struct object_id *a_oid,
1645                          unsigned a_mode,
1646                          int renormalize, const char *path)
1647{
1648        struct strbuf o = STRBUF_INIT;
1649        struct strbuf a = STRBUF_INIT;
1650        int ret = 0; /* assume changed for safety */
1651
1652        if (a_mode != o_mode)
1653                return 0;
1654        if (oid_eq(o_oid, a_oid))
1655                return 1;
1656        if (!renormalize)
1657                return 0;
1658
1659        assert(o_oid && a_oid);
1660        if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
1661                goto error_return;
1662        /*
1663         * Note: binary | is used so that both renormalizations are
1664         * performed.  Comparison can be skipped if both files are
1665         * unchanged since their sha1s have already been compared.
1666         */
1667        if (renormalize_buffer(&the_index, path, o.buf, o.len, &o) |
1668            renormalize_buffer(&the_index, path, a.buf, a.len, &a))
1669                ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1670
1671error_return:
1672        strbuf_release(&o);
1673        strbuf_release(&a);
1674        return ret;
1675}
1676
1677static int handle_modify_delete(struct merge_options *o,
1678                                 const char *path,
1679                                 struct object_id *o_oid, int o_mode,
1680                                 struct object_id *a_oid, int a_mode,
1681                                 struct object_id *b_oid, int b_mode)
1682{
1683        const char *modify_branch, *delete_branch;
1684        struct object_id *changed_oid;
1685        int changed_mode;
1686
1687        if (a_oid) {
1688                modify_branch = o->branch1;
1689                delete_branch = o->branch2;
1690                changed_oid = a_oid;
1691                changed_mode = a_mode;
1692        } else {
1693                modify_branch = o->branch2;
1694                delete_branch = o->branch1;
1695                changed_oid = b_oid;
1696                changed_mode = b_mode;
1697        }
1698
1699        return handle_change_delete(o,
1700                                    path, NULL,
1701                                    o_oid, o_mode,
1702                                    changed_oid, changed_mode,
1703                                    modify_branch, delete_branch,
1704                                    _("modify"), _("modified"));
1705}
1706
1707static int merge_content(struct merge_options *o,
1708                         const char *path,
1709                         struct object_id *o_oid, int o_mode,
1710                         struct object_id *a_oid, int a_mode,
1711                         struct object_id *b_oid, int b_mode,
1712                         struct rename_conflict_info *rename_conflict_info)
1713{
1714        const char *reason = _("content");
1715        const char *path1 = NULL, *path2 = NULL;
1716        struct merge_file_info mfi;
1717        struct diff_filespec one, a, b;
1718        unsigned df_conflict_remains = 0;
1719
1720        if (!o_oid) {
1721                reason = _("add/add");
1722                o_oid = (struct object_id *)&null_oid;
1723        }
1724        one.path = a.path = b.path = (char *)path;
1725        oidcpy(&one.oid, o_oid);
1726        one.mode = o_mode;
1727        oidcpy(&a.oid, a_oid);
1728        a.mode = a_mode;
1729        oidcpy(&b.oid, b_oid);
1730        b.mode = b_mode;
1731
1732        if (rename_conflict_info) {
1733                struct diff_filepair *pair1 = rename_conflict_info->pair1;
1734
1735                path1 = (o->branch1 == rename_conflict_info->branch1) ?
1736                        pair1->two->path : pair1->one->path;
1737                /* If rename_conflict_info->pair2 != NULL, we are in
1738                 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1739                 * normal rename.
1740                 */
1741                path2 = (rename_conflict_info->pair2 ||
1742                         o->branch2 == rename_conflict_info->branch1) ?
1743                        pair1->two->path : pair1->one->path;
1744
1745                if (dir_in_way(path, !o->call_depth,
1746                               S_ISGITLINK(pair1->two->mode)))
1747                        df_conflict_remains = 1;
1748        }
1749        if (merge_file_special_markers(o, &one, &a, &b,
1750                                       o->branch1, path1,
1751                                       o->branch2, path2, &mfi))
1752                return -1;
1753
1754        if (mfi.clean && !df_conflict_remains &&
1755            oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
1756                int path_renamed_outside_HEAD;
1757                output(o, 3, _("Skipped %s (merged same as existing)"), path);
1758                /*
1759                 * The content merge resulted in the same file contents we
1760                 * already had.  We can return early if those file contents
1761                 * are recorded at the correct path (which may not be true
1762                 * if the merge involves a rename).
1763                 */
1764                path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1765                if (!path_renamed_outside_HEAD) {
1766                        add_cacheinfo(o, mfi.mode, &mfi.oid, path,
1767                                      0, (!o->call_depth), 0);
1768                        return mfi.clean;
1769                }
1770        } else
1771                output(o, 2, _("Auto-merging %s"), path);
1772
1773        if (!mfi.clean) {
1774                if (S_ISGITLINK(mfi.mode))
1775                        reason = _("submodule");
1776                output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1777                                reason, path);
1778                if (rename_conflict_info && !df_conflict_remains)
1779                        if (update_stages(o, path, &one, &a, &b))
1780                                return -1;
1781        }
1782
1783        if (df_conflict_remains) {
1784                char *new_path;
1785                if (o->call_depth) {
1786                        remove_file_from_cache(path);
1787                } else {
1788                        if (!mfi.clean) {
1789                                if (update_stages(o, path, &one, &a, &b))
1790                                        return -1;
1791                        } else {
1792                                int file_from_stage2 = was_tracked(path);
1793                                struct diff_filespec merged;
1794                                oidcpy(&merged.oid, &mfi.oid);
1795                                merged.mode = mfi.mode;
1796
1797                                if (update_stages(o, path, NULL,
1798                                                  file_from_stage2 ? &merged : NULL,
1799                                                  file_from_stage2 ? NULL : &merged))
1800                                        return -1;
1801                        }
1802
1803                }
1804                new_path = unique_path(o, path, rename_conflict_info->branch1);
1805                output(o, 1, _("Adding as %s instead"), new_path);
1806                if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
1807                        free(new_path);
1808                        return -1;
1809                }
1810                free(new_path);
1811                mfi.clean = 0;
1812        } else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
1813                return -1;
1814        return mfi.clean;
1815}
1816
1817/* Per entry merge function */
1818static int process_entry(struct merge_options *o,
1819                         const char *path, struct stage_data *entry)
1820{
1821        int clean_merge = 1;
1822        int normalize = o->renormalize;
1823        unsigned o_mode = entry->stages[1].mode;
1824        unsigned a_mode = entry->stages[2].mode;
1825        unsigned b_mode = entry->stages[3].mode;
1826        struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
1827        struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
1828        struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
1829
1830        entry->processed = 1;
1831        if (entry->rename_conflict_info) {
1832                struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1833                switch (conflict_info->rename_type) {
1834                case RENAME_NORMAL:
1835                case RENAME_ONE_FILE_TO_ONE:
1836                        clean_merge = merge_content(o, path,
1837                                                    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1838                                                    conflict_info);
1839                        break;
1840                case RENAME_DELETE:
1841                        clean_merge = 0;
1842                        if (conflict_rename_delete(o,
1843                                                   conflict_info->pair1,
1844                                                   conflict_info->branch1,
1845                                                   conflict_info->branch2))
1846                                clean_merge = -1;
1847                        break;
1848                case RENAME_ONE_FILE_TO_TWO:
1849                        clean_merge = 0;
1850                        if (conflict_rename_rename_1to2(o, conflict_info))
1851                                clean_merge = -1;
1852                        break;
1853                case RENAME_TWO_FILES_TO_ONE:
1854                        clean_merge = 0;
1855                        if (conflict_rename_rename_2to1(o, conflict_info))
1856                                clean_merge = -1;
1857                        break;
1858                default:
1859                        entry->processed = 0;
1860                        break;
1861                }
1862        } else if (o_oid && (!a_oid || !b_oid)) {
1863                /* Case A: Deleted in one */
1864                if ((!a_oid && !b_oid) ||
1865                    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
1866                    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
1867                        /* Deleted in both or deleted in one and
1868                         * unchanged in the other */
1869                        if (a_oid)
1870                                output(o, 2, _("Removing %s"), path);
1871                        /* do not touch working file if it did not exist */
1872                        remove_file(o, 1, path, !a_oid);
1873                } else {
1874                        /* Modify/delete; deleted side may have put a directory in the way */
1875                        clean_merge = 0;
1876                        if (handle_modify_delete(o, path, o_oid, o_mode,
1877                                                 a_oid, a_mode, b_oid, b_mode))
1878                                clean_merge = -1;
1879                }
1880        } else if ((!o_oid && a_oid && !b_oid) ||
1881                   (!o_oid && !a_oid && b_oid)) {
1882                /* Case B: Added in one. */
1883                /* [nothing|directory] -> ([nothing|directory], file) */
1884
1885                const char *add_branch;
1886                const char *other_branch;
1887                unsigned mode;
1888                const struct object_id *oid;
1889                const char *conf;
1890
1891                if (a_oid) {
1892                        add_branch = o->branch1;
1893                        other_branch = o->branch2;
1894                        mode = a_mode;
1895                        oid = a_oid;
1896                        conf = _("file/directory");
1897                } else {
1898                        add_branch = o->branch2;
1899                        other_branch = o->branch1;
1900                        mode = b_mode;
1901                        oid = b_oid;
1902                        conf = _("directory/file");
1903                }
1904                if (dir_in_way(path,
1905                               !o->call_depth && !S_ISGITLINK(a_mode),
1906                               0)) {
1907                        char *new_path = unique_path(o, path, add_branch);
1908                        clean_merge = 0;
1909                        output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1910                               "Adding %s as %s"),
1911                               conf, path, other_branch, path, new_path);
1912                        if (update_file(o, 0, oid, mode, new_path))
1913                                clean_merge = -1;
1914                        else if (o->call_depth)
1915                                remove_file_from_cache(path);
1916                        free(new_path);
1917                } else {
1918                        output(o, 2, _("Adding %s"), path);
1919                        /* do not overwrite file if already present */
1920                        if (update_file_flags(o, oid, mode, path, 1, !a_oid))
1921                                clean_merge = -1;
1922                }
1923        } else if (a_oid && b_oid) {
1924                /* Case C: Added in both (check for same permissions) and */
1925                /* case D: Modified in both, but differently. */
1926                clean_merge = merge_content(o, path,
1927                                            o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1928                                            NULL);
1929        } else if (!o_oid && !a_oid && !b_oid) {
1930                /*
1931                 * this entry was deleted altogether. a_mode == 0 means
1932                 * we had that path and want to actively remove it.
1933                 */
1934                remove_file(o, 1, path, !a_mode);
1935        } else
1936                die("BUG: fatal merge failure, shouldn't happen.");
1937
1938        return clean_merge;
1939}
1940
1941int merge_trees(struct merge_options *o,
1942                struct tree *head,
1943                struct tree *merge,
1944                struct tree *common,
1945                struct tree **result)
1946{
1947        int code, clean;
1948
1949        if (o->subtree_shift) {
1950                merge = shift_tree_object(head, merge, o->subtree_shift);
1951                common = shift_tree_object(head, common, o->subtree_shift);
1952        }
1953
1954        if (oid_eq(&common->object.oid, &merge->object.oid)) {
1955                output(o, 0, _("Already up to date!"));
1956                *result = head;
1957                return 1;
1958        }
1959
1960        code = git_merge_trees(o->call_depth, common, head, merge);
1961
1962        if (code != 0) {
1963                if (show(o, 4) || o->call_depth)
1964                        err(o, _("merging of trees %s and %s failed"),
1965                            oid_to_hex(&head->object.oid),
1966                            oid_to_hex(&merge->object.oid));
1967                return -1;
1968        }
1969
1970        if (unmerged_cache()) {
1971                struct string_list *entries, *re_head, *re_merge;
1972                int i;
1973                /*
1974                 * Only need the hashmap while processing entries, so
1975                 * initialize it here and free it when we are done running
1976                 * through the entries. Keeping it in the merge_options as
1977                 * opposed to decaring a local hashmap is for convenience
1978                 * so that we don't have to pass it to around.
1979                 */
1980                hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
1981                get_files_dirs(o, head);
1982                get_files_dirs(o, merge);
1983
1984                entries = get_unmerged();
1985                record_df_conflict_files(o, entries);
1986                re_head  = get_renames(o, head, common, head, merge, entries);
1987                re_merge = get_renames(o, merge, common, head, merge, entries);
1988                clean = process_renames(o, re_head, re_merge);
1989                if (clean < 0)
1990                        goto cleanup;
1991                for (i = entries->nr-1; 0 <= i; i--) {
1992                        const char *path = entries->items[i].string;
1993                        struct stage_data *e = entries->items[i].util;
1994                        if (!e->processed) {
1995                                int ret = process_entry(o, path, e);
1996                                if (!ret)
1997                                        clean = 0;
1998                                else if (ret < 0) {
1999                                        clean = ret;
2000                                        goto cleanup;
2001                                }
2002                        }
2003                }
2004                for (i = 0; i < entries->nr; i++) {
2005                        struct stage_data *e = entries->items[i].util;
2006                        if (!e->processed)
2007                                die("BUG: unprocessed path??? %s",
2008                                    entries->items[i].string);
2009                }
2010
2011cleanup:
2012                string_list_clear(re_merge, 0);
2013                string_list_clear(re_head, 0);
2014                string_list_clear(entries, 1);
2015
2016                hashmap_free(&o->current_file_dir_set, 1);
2017
2018                free(re_merge);
2019                free(re_head);
2020                free(entries);
2021
2022                if (clean < 0)
2023                        return clean;
2024        }
2025        else
2026                clean = 1;
2027
2028        if (o->call_depth && !(*result = write_tree_from_memory(o)))
2029                return -1;
2030
2031        return clean;
2032}
2033
2034static struct commit_list *reverse_commit_list(struct commit_list *list)
2035{
2036        struct commit_list *next = NULL, *current, *backup;
2037        for (current = list; current; current = backup) {
2038                backup = current->next;
2039                current->next = next;
2040                next = current;
2041        }
2042        return next;
2043}
2044
2045/*
2046 * Merge the commits h1 and h2, return the resulting virtual
2047 * commit object and a flag indicating the cleanness of the merge.
2048 */
2049int merge_recursive(struct merge_options *o,
2050                    struct commit *h1,
2051                    struct commit *h2,
2052                    struct commit_list *ca,
2053                    struct commit **result)
2054{
2055        struct commit_list *iter;
2056        struct commit *merged_common_ancestors;
2057        struct tree *mrtree = mrtree;
2058        int clean;
2059
2060        if (show(o, 4)) {
2061                output(o, 4, _("Merging:"));
2062                output_commit_title(o, h1);
2063                output_commit_title(o, h2);
2064        }
2065
2066        if (!ca) {
2067                ca = get_merge_bases(h1, h2);
2068                ca = reverse_commit_list(ca);
2069        }
2070
2071        if (show(o, 5)) {
2072                unsigned cnt = commit_list_count(ca);
2073
2074                output(o, 5, Q_("found %u common ancestor:",
2075                                "found %u common ancestors:", cnt), cnt);
2076                for (iter = ca; iter; iter = iter->next)
2077                        output_commit_title(o, iter->item);
2078        }
2079
2080        merged_common_ancestors = pop_commit(&ca);
2081        if (merged_common_ancestors == NULL) {
2082                /* if there is no common ancestor, use an empty tree */
2083                struct tree *tree;
2084
2085                tree = lookup_tree(the_hash_algo->empty_tree);
2086                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
2087        }
2088
2089        for (iter = ca; iter; iter = iter->next) {
2090                const char *saved_b1, *saved_b2;
2091                o->call_depth++;
2092                /*
2093                 * When the merge fails, the result contains files
2094                 * with conflict markers. The cleanness flag is
2095                 * ignored (unless indicating an error), it was never
2096                 * actually used, as result of merge_trees has always
2097                 * overwritten it: the committed "conflicts" were
2098                 * already resolved.
2099                 */
2100                discard_cache();
2101                saved_b1 = o->branch1;
2102                saved_b2 = o->branch2;
2103                o->branch1 = "Temporary merge branch 1";
2104                o->branch2 = "Temporary merge branch 2";
2105                if (merge_recursive(o, merged_common_ancestors, iter->item,
2106                                    NULL, &merged_common_ancestors) < 0)
2107                        return -1;
2108                o->branch1 = saved_b1;
2109                o->branch2 = saved_b2;
2110                o->call_depth--;
2111
2112                if (!merged_common_ancestors)
2113                        return err(o, _("merge returned no commit"));
2114        }
2115
2116        discard_cache();
2117        if (!o->call_depth)
2118                read_cache();
2119
2120        o->ancestor = "merged common ancestors";
2121        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
2122                            &mrtree);
2123        if (clean < 0) {
2124                flush_output(o);
2125                return clean;
2126        }
2127
2128        if (o->call_depth) {
2129                *result = make_virtual_commit(mrtree, "merged tree");
2130                commit_list_insert(h1, &(*result)->parents);
2131                commit_list_insert(h2, &(*result)->parents->next);
2132        }
2133        flush_output(o);
2134        if (!o->call_depth && o->buffer_output < 2)
2135                strbuf_release(&o->obuf);
2136        if (show(o, 2))
2137                diff_warn_rename_limit("merge.renamelimit",
2138                                       o->needed_rename_limit, 0);
2139        return clean;
2140}
2141
2142static struct commit *get_ref(const struct object_id *oid, const char *name)
2143{
2144        struct object *object;
2145
2146        object = deref_tag(parse_object(oid), name, strlen(name));
2147        if (!object)
2148                return NULL;
2149        if (object->type == OBJ_TREE)
2150                return make_virtual_commit((struct tree*)object, name);
2151        if (object->type != OBJ_COMMIT)
2152                return NULL;
2153        if (parse_commit((struct commit *)object))
2154                return NULL;
2155        return (struct commit *)object;
2156}
2157
2158int merge_recursive_generic(struct merge_options *o,
2159                            const struct object_id *head,
2160                            const struct object_id *merge,
2161                            int num_base_list,
2162                            const struct object_id **base_list,
2163                            struct commit **result)
2164{
2165        int clean;
2166        struct lock_file lock = LOCK_INIT;
2167        struct commit *head_commit = get_ref(head, o->branch1);
2168        struct commit *next_commit = get_ref(merge, o->branch2);
2169        struct commit_list *ca = NULL;
2170
2171        if (base_list) {
2172                int i;
2173                for (i = 0; i < num_base_list; ++i) {
2174                        struct commit *base;
2175                        if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
2176                                return err(o, _("Could not parse object '%s'"),
2177                                        oid_to_hex(base_list[i]));
2178                        commit_list_insert(base, &ca);
2179                }
2180        }
2181
2182        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
2183        clean = merge_recursive(o, head_commit, next_commit, ca,
2184                        result);
2185        if (clean < 0)
2186                return clean;
2187
2188        if (active_cache_changed &&
2189            write_locked_index(&the_index, &lock, COMMIT_LOCK))
2190                return err(o, _("Unable to write index."));
2191
2192        return clean ? 0 : 1;
2193}
2194
2195static void merge_recursive_config(struct merge_options *o)
2196{
2197        git_config_get_int("merge.verbosity", &o->verbosity);
2198        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2199        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2200        git_config(git_xmerge_config, NULL);
2201}
2202
2203void init_merge_options(struct merge_options *o)
2204{
2205        const char *merge_verbosity;
2206        memset(o, 0, sizeof(struct merge_options));
2207        o->verbosity = 2;
2208        o->buffer_output = 1;
2209        o->diff_rename_limit = -1;
2210        o->merge_rename_limit = -1;
2211        o->renormalize = 0;
2212        o->detect_rename = 1;
2213        merge_recursive_config(o);
2214        merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
2215        if (merge_verbosity)
2216                o->verbosity = strtol(merge_verbosity, NULL, 10);
2217        if (o->verbosity >= 5)
2218                o->buffer_output = 0;
2219        strbuf_init(&o->obuf, 0);
2220        string_list_init(&o->df_conflict_file_set, 1);
2221}
2222
2223int parse_merge_opt(struct merge_options *o, const char *s)
2224{
2225        const char *arg;
2226
2227        if (!s || !*s)
2228                return -1;
2229        if (!strcmp(s, "ours"))
2230                o->recursive_variant = MERGE_RECURSIVE_OURS;
2231        else if (!strcmp(s, "theirs"))
2232                o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2233        else if (!strcmp(s, "subtree"))
2234                o->subtree_shift = "";
2235        else if (skip_prefix(s, "subtree=", &arg))
2236                o->subtree_shift = arg;
2237        else if (!strcmp(s, "patience"))
2238                o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2239        else if (!strcmp(s, "histogram"))
2240                o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2241        else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2242                long value = parse_algorithm_value(arg);
2243                if (value < 0)
2244                        return -1;
2245                /* clear out previous settings */
2246                DIFF_XDL_CLR(o, NEED_MINIMAL);
2247                o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2248                o->xdl_opts |= value;
2249        }
2250        else if (!strcmp(s, "ignore-space-change"))
2251                DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
2252        else if (!strcmp(s, "ignore-all-space"))
2253                DIFF_XDL_SET(o, IGNORE_WHITESPACE);
2254        else if (!strcmp(s, "ignore-space-at-eol"))
2255                DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
2256        else if (!strcmp(s, "ignore-cr-at-eol"))
2257                DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
2258        else if (!strcmp(s, "renormalize"))
2259                o->renormalize = 1;
2260        else if (!strcmp(s, "no-renormalize"))
2261                o->renormalize = 0;
2262        else if (!strcmp(s, "no-renames"))
2263                o->detect_rename = 0;
2264        else if (!strcmp(s, "find-renames")) {
2265                o->detect_rename = 1;
2266                o->rename_score = 0;
2267        }
2268        else if (skip_prefix(s, "find-renames=", &arg) ||
2269                 skip_prefix(s, "rename-threshold=", &arg)) {
2270                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2271                        return -1;
2272                o->detect_rename = 1;
2273        }
2274        else
2275                return -1;
2276        return 0;
2277}