2cbdb9939a79ae1d0fe6eab72170d0be3bac25df
   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 struct dir_rename_entry *dir_rename_find_entry(struct hashmap *hashmap,
  53                                                      char *dir)
  54{
  55        struct dir_rename_entry key;
  56
  57        if (dir == NULL)
  58                return NULL;
  59        hashmap_entry_init(&key, strhash(dir));
  60        key.dir = dir;
  61        return hashmap_get(hashmap, &key, NULL);
  62}
  63
  64static int dir_rename_cmp(const void *unused_cmp_data,
  65                          const void *entry,
  66                          const void *entry_or_key,
  67                          const void *unused_keydata)
  68{
  69        const struct dir_rename_entry *e1 = entry;
  70        const struct dir_rename_entry *e2 = entry_or_key;
  71
  72        return strcmp(e1->dir, e2->dir);
  73}
  74
  75static void dir_rename_init(struct hashmap *map)
  76{
  77        hashmap_init(map, dir_rename_cmp, NULL, 0);
  78}
  79
  80static void dir_rename_entry_init(struct dir_rename_entry *entry,
  81                                  char *directory)
  82{
  83        hashmap_entry_init(entry, strhash(directory));
  84        entry->dir = directory;
  85        entry->non_unique_new_dir = 0;
  86        strbuf_init(&entry->new_dir, 0);
  87        string_list_init(&entry->possible_new_dirs, 0);
  88}
  89
  90static struct collision_entry *collision_find_entry(struct hashmap *hashmap,
  91                                                    char *target_file)
  92{
  93        struct collision_entry key;
  94
  95        hashmap_entry_init(&key, strhash(target_file));
  96        key.target_file = target_file;
  97        return hashmap_get(hashmap, &key, NULL);
  98}
  99
 100static int collision_cmp(void *unused_cmp_data,
 101                         const struct collision_entry *e1,
 102                         const struct collision_entry *e2,
 103                         const void *unused_keydata)
 104{
 105        return strcmp(e1->target_file, e2->target_file);
 106}
 107
 108static void collision_init(struct hashmap *map)
 109{
 110        hashmap_init(map, (hashmap_cmp_fn) collision_cmp, NULL, 0);
 111}
 112
 113static void flush_output(struct merge_options *o)
 114{
 115        if (o->buffer_output < 2 && o->obuf.len) {
 116                fputs(o->obuf.buf, stdout);
 117                strbuf_reset(&o->obuf);
 118        }
 119}
 120
 121static int err(struct merge_options *o, const char *err, ...)
 122{
 123        va_list params;
 124
 125        if (o->buffer_output < 2)
 126                flush_output(o);
 127        else {
 128                strbuf_complete(&o->obuf, '\n');
 129                strbuf_addstr(&o->obuf, "error: ");
 130        }
 131        va_start(params, err);
 132        strbuf_vaddf(&o->obuf, err, params);
 133        va_end(params);
 134        if (o->buffer_output > 1)
 135                strbuf_addch(&o->obuf, '\n');
 136        else {
 137                error("%s", o->obuf.buf);
 138                strbuf_reset(&o->obuf);
 139        }
 140
 141        return -1;
 142}
 143
 144static struct tree *shift_tree_object(struct tree *one, struct tree *two,
 145                                      const char *subtree_shift)
 146{
 147        struct object_id shifted;
 148
 149        if (!*subtree_shift) {
 150                shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
 151        } else {
 152                shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
 153                              subtree_shift);
 154        }
 155        if (!oidcmp(&two->object.oid, &shifted))
 156                return two;
 157        return lookup_tree(&shifted);
 158}
 159
 160static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
 161{
 162        struct commit *commit = alloc_commit_node();
 163
 164        set_merge_remote_desc(commit, comment, (struct object *)commit);
 165        commit->tree = tree;
 166        commit->object.parsed = 1;
 167        return commit;
 168}
 169
 170/*
 171 * Since we use get_tree_entry(), which does not put the read object into
 172 * the object pool, we cannot rely on a == b.
 173 */
 174static int oid_eq(const struct object_id *a, const struct object_id *b)
 175{
 176        if (!a && !b)
 177                return 2;
 178        return a && b && oidcmp(a, b) == 0;
 179}
 180
 181enum rename_type {
 182        RENAME_NORMAL = 0,
 183        RENAME_DELETE,
 184        RENAME_ONE_FILE_TO_ONE,
 185        RENAME_ONE_FILE_TO_TWO,
 186        RENAME_TWO_FILES_TO_ONE
 187};
 188
 189struct rename_conflict_info {
 190        enum rename_type rename_type;
 191        struct diff_filepair *pair1;
 192        struct diff_filepair *pair2;
 193        const char *branch1;
 194        const char *branch2;
 195        struct stage_data *dst_entry1;
 196        struct stage_data *dst_entry2;
 197        struct diff_filespec ren1_other;
 198        struct diff_filespec ren2_other;
 199};
 200
 201/*
 202 * Since we want to write the index eventually, we cannot reuse the index
 203 * for these (temporary) data.
 204 */
 205struct stage_data {
 206        struct {
 207                unsigned mode;
 208                struct object_id oid;
 209        } stages[4];
 210        struct rename_conflict_info *rename_conflict_info;
 211        unsigned processed:1;
 212};
 213
 214static inline void setup_rename_conflict_info(enum rename_type rename_type,
 215                                              struct diff_filepair *pair1,
 216                                              struct diff_filepair *pair2,
 217                                              const char *branch1,
 218                                              const char *branch2,
 219                                              struct stage_data *dst_entry1,
 220                                              struct stage_data *dst_entry2,
 221                                              struct merge_options *o,
 222                                              struct stage_data *src_entry1,
 223                                              struct stage_data *src_entry2)
 224{
 225        struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
 226        ci->rename_type = rename_type;
 227        ci->pair1 = pair1;
 228        ci->branch1 = branch1;
 229        ci->branch2 = branch2;
 230
 231        ci->dst_entry1 = dst_entry1;
 232        dst_entry1->rename_conflict_info = ci;
 233        dst_entry1->processed = 0;
 234
 235        assert(!pair2 == !dst_entry2);
 236        if (dst_entry2) {
 237                ci->dst_entry2 = dst_entry2;
 238                ci->pair2 = pair2;
 239                dst_entry2->rename_conflict_info = ci;
 240        }
 241
 242        if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 243                /*
 244                 * For each rename, there could have been
 245                 * modifications on the side of history where that
 246                 * file was not renamed.
 247                 */
 248                int ostage1 = o->branch1 == branch1 ? 3 : 2;
 249                int ostage2 = ostage1 ^ 1;
 250
 251                ci->ren1_other.path = pair1->one->path;
 252                oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 253                ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 254
 255                ci->ren2_other.path = pair2->one->path;
 256                oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 257                ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 258        }
 259}
 260
 261static int show(struct merge_options *o, int v)
 262{
 263        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 264}
 265
 266__attribute__((format (printf, 3, 4)))
 267static void output(struct merge_options *o, int v, const char *fmt, ...)
 268{
 269        va_list ap;
 270
 271        if (!show(o, v))
 272                return;
 273
 274        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 275
 276        va_start(ap, fmt);
 277        strbuf_vaddf(&o->obuf, fmt, ap);
 278        va_end(ap);
 279
 280        strbuf_addch(&o->obuf, '\n');
 281        if (!o->buffer_output)
 282                flush_output(o);
 283}
 284
 285static void output_commit_title(struct merge_options *o, struct commit *commit)
 286{
 287        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 288        if (commit->util)
 289                strbuf_addf(&o->obuf, "virtual %s\n",
 290                        merge_remote_util(commit)->name);
 291        else {
 292                strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
 293                                         DEFAULT_ABBREV);
 294                strbuf_addch(&o->obuf, ' ');
 295                if (parse_commit(commit) != 0)
 296                        strbuf_addstr(&o->obuf, _("(bad commit)\n"));
 297                else {
 298                        const char *title;
 299                        const char *msg = get_commit_buffer(commit, NULL);
 300                        int len = find_commit_subject(msg, &title);
 301                        if (len)
 302                                strbuf_addf(&o->obuf, "%.*s\n", len, title);
 303                        unuse_commit_buffer(commit, msg);
 304                }
 305        }
 306        flush_output(o);
 307}
 308
 309static int add_cacheinfo(struct merge_options *o,
 310                unsigned int mode, const struct object_id *oid,
 311                const char *path, int stage, int refresh, int options)
 312{
 313        struct cache_entry *ce;
 314        int ret;
 315
 316        ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
 317        if (!ce)
 318                return err(o, _("addinfo_cache failed for path '%s'"), path);
 319
 320        ret = add_cache_entry(ce, options);
 321        if (refresh) {
 322                struct cache_entry *nce;
 323
 324                nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 325                if (!nce)
 326                        return err(o, _("addinfo_cache failed for path '%s'"), path);
 327                if (nce != ce)
 328                        ret = add_cache_entry(nce, options);
 329        }
 330        return ret;
 331}
 332
 333static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 334{
 335        parse_tree(tree);
 336        init_tree_desc(desc, tree->buffer, tree->size);
 337}
 338
 339static int git_merge_trees(int index_only,
 340                           struct tree *common,
 341                           struct tree *head,
 342                           struct tree *merge)
 343{
 344        int rc;
 345        struct tree_desc t[3];
 346        struct unpack_trees_options opts;
 347
 348        memset(&opts, 0, sizeof(opts));
 349        if (index_only)
 350                opts.index_only = 1;
 351        else
 352                opts.update = 1;
 353        opts.merge = 1;
 354        opts.head_idx = 2;
 355        opts.fn = threeway_merge;
 356        opts.src_index = &the_index;
 357        opts.dst_index = &the_index;
 358        setup_unpack_trees_porcelain(&opts, "merge");
 359
 360        init_tree_desc_from_tree(t+0, common);
 361        init_tree_desc_from_tree(t+1, head);
 362        init_tree_desc_from_tree(t+2, merge);
 363
 364        rc = unpack_trees(3, t, &opts);
 365        cache_tree_free(&active_cache_tree);
 366        return rc;
 367}
 368
 369struct tree *write_tree_from_memory(struct merge_options *o)
 370{
 371        struct tree *result = NULL;
 372
 373        if (unmerged_cache()) {
 374                int i;
 375                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 376                for (i = 0; i < active_nr; i++) {
 377                        const struct cache_entry *ce = active_cache[i];
 378                        if (ce_stage(ce))
 379                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 380                                        (int)ce_namelen(ce), ce->name);
 381                }
 382                die("BUG: unmerged index entries in merge-recursive.c");
 383        }
 384
 385        if (!active_cache_tree)
 386                active_cache_tree = cache_tree();
 387
 388        if (!cache_tree_fully_valid(active_cache_tree) &&
 389            cache_tree_update(&the_index, 0) < 0) {
 390                err(o, _("error building trees"));
 391                return NULL;
 392        }
 393
 394        result = lookup_tree(&active_cache_tree->oid);
 395
 396        return result;
 397}
 398
 399static int save_files_dirs(const unsigned char *sha1,
 400                struct strbuf *base, const char *path,
 401                unsigned int mode, int stage, void *context)
 402{
 403        struct path_hashmap_entry *entry;
 404        int baselen = base->len;
 405        struct merge_options *o = context;
 406
 407        strbuf_addstr(base, path);
 408
 409        FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 410        hashmap_entry_init(entry, path_hash(entry->path));
 411        hashmap_add(&o->current_file_dir_set, entry);
 412
 413        strbuf_setlen(base, baselen);
 414        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 415}
 416
 417static void get_files_dirs(struct merge_options *o, struct tree *tree)
 418{
 419        struct pathspec match_all;
 420        memset(&match_all, 0, sizeof(match_all));
 421        read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o);
 422}
 423
 424/*
 425 * Returns an index_entry instance which doesn't have to correspond to
 426 * a real cache entry in Git's index.
 427 */
 428static struct stage_data *insert_stage_data(const char *path,
 429                struct tree *o, struct tree *a, struct tree *b,
 430                struct string_list *entries)
 431{
 432        struct string_list_item *item;
 433        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 434        get_tree_entry(o->object.oid.hash, path,
 435                        e->stages[1].oid.hash, &e->stages[1].mode);
 436        get_tree_entry(a->object.oid.hash, path,
 437                        e->stages[2].oid.hash, &e->stages[2].mode);
 438        get_tree_entry(b->object.oid.hash, path,
 439                        e->stages[3].oid.hash, &e->stages[3].mode);
 440        item = string_list_insert(entries, path);
 441        item->util = e;
 442        return e;
 443}
 444
 445/*
 446 * Create a dictionary mapping file names to stage_data objects. The
 447 * dictionary contains one entry for every path with a non-zero stage entry.
 448 */
 449static struct string_list *get_unmerged(void)
 450{
 451        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 452        int i;
 453
 454        unmerged->strdup_strings = 1;
 455
 456        for (i = 0; i < active_nr; i++) {
 457                struct string_list_item *item;
 458                struct stage_data *e;
 459                const struct cache_entry *ce = active_cache[i];
 460                if (!ce_stage(ce))
 461                        continue;
 462
 463                item = string_list_lookup(unmerged, ce->name);
 464                if (!item) {
 465                        item = string_list_insert(unmerged, ce->name);
 466                        item->util = xcalloc(1, sizeof(struct stage_data));
 467                }
 468                e = item->util;
 469                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 470                oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
 471        }
 472
 473        return unmerged;
 474}
 475
 476static int string_list_df_name_compare(const char *one, const char *two)
 477{
 478        int onelen = strlen(one);
 479        int twolen = strlen(two);
 480        /*
 481         * Here we only care that entries for D/F conflicts are
 482         * adjacent, in particular with the file of the D/F conflict
 483         * appearing before files below the corresponding directory.
 484         * The order of the rest of the list is irrelevant for us.
 485         *
 486         * To achieve this, we sort with df_name_compare and provide
 487         * the mode S_IFDIR so that D/F conflicts will sort correctly.
 488         * We use the mode S_IFDIR for everything else for simplicity,
 489         * since in other cases any changes in their order due to
 490         * sorting cause no problems for us.
 491         */
 492        int cmp = df_name_compare(one, onelen, S_IFDIR,
 493                                  two, twolen, S_IFDIR);
 494        /*
 495         * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 496         * that 'foo' comes before 'foo/bar'.
 497         */
 498        if (cmp)
 499                return cmp;
 500        return onelen - twolen;
 501}
 502
 503static void record_df_conflict_files(struct merge_options *o,
 504                                     struct string_list *entries)
 505{
 506        /* If there is a D/F conflict and the file for such a conflict
 507         * currently exist in the working tree, we want to allow it to be
 508         * removed to make room for the corresponding directory if needed.
 509         * The files underneath the directories of such D/F conflicts will
 510         * be processed before the corresponding file involved in the D/F
 511         * conflict.  If the D/F directory ends up being removed by the
 512         * merge, then we won't have to touch the D/F file.  If the D/F
 513         * directory needs to be written to the working copy, then the D/F
 514         * file will simply be removed (in make_room_for_path()) to make
 515         * room for the necessary paths.  Note that if both the directory
 516         * and the file need to be present, then the D/F file will be
 517         * reinstated with a new unique name at the time it is processed.
 518         */
 519        struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
 520        const char *last_file = NULL;
 521        int last_len = 0;
 522        int i;
 523
 524        /*
 525         * If we're merging merge-bases, we don't want to bother with
 526         * any working directory changes.
 527         */
 528        if (o->call_depth)
 529                return;
 530
 531        /* Ensure D/F conflicts are adjacent in the entries list. */
 532        for (i = 0; i < entries->nr; i++) {
 533                struct string_list_item *next = &entries->items[i];
 534                string_list_append(&df_sorted_entries, next->string)->util =
 535                                   next->util;
 536        }
 537        df_sorted_entries.cmp = string_list_df_name_compare;
 538        string_list_sort(&df_sorted_entries);
 539
 540        string_list_clear(&o->df_conflict_file_set, 1);
 541        for (i = 0; i < df_sorted_entries.nr; i++) {
 542                const char *path = df_sorted_entries.items[i].string;
 543                int len = strlen(path);
 544                struct stage_data *e = df_sorted_entries.items[i].util;
 545
 546                /*
 547                 * Check if last_file & path correspond to a D/F conflict;
 548                 * i.e. whether path is last_file+'/'+<something>.
 549                 * If so, record that it's okay to remove last_file to make
 550                 * room for path and friends if needed.
 551                 */
 552                if (last_file &&
 553                    len > last_len &&
 554                    memcmp(path, last_file, last_len) == 0 &&
 555                    path[last_len] == '/') {
 556                        string_list_insert(&o->df_conflict_file_set, last_file);
 557                }
 558
 559                /*
 560                 * Determine whether path could exist as a file in the
 561                 * working directory as a possible D/F conflict.  This
 562                 * will only occur when it exists in stage 2 as a
 563                 * file.
 564                 */
 565                if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 566                        last_file = path;
 567                        last_len = len;
 568                } else {
 569                        last_file = NULL;
 570                }
 571        }
 572        string_list_clear(&df_sorted_entries, 0);
 573}
 574
 575struct rename {
 576        struct diff_filepair *pair;
 577        /*
 578         * Purpose of src_entry and dst_entry:
 579         *
 580         * If 'before' is renamed to 'after' then src_entry will contain
 581         * the versions of 'before' from the merge_base, HEAD, and MERGE in
 582         * stages 1, 2, and 3; dst_entry will contain the respective
 583         * versions of 'after' in corresponding locations.  Thus, we have a
 584         * total of six modes and oids, though some will be null.  (Stage 0
 585         * is ignored; we're interested in handling conflicts.)
 586         *
 587         * Since we don't turn on break-rewrites by default, neither
 588         * src_entry nor dst_entry can have all three of their stages have
 589         * non-null oids, meaning at most four of the six will be non-null.
 590         * Also, since this is a rename, both src_entry and dst_entry will
 591         * have at least one non-null oid, meaning at least two will be
 592         * non-null.  Of the six oids, a typical rename will have three be
 593         * non-null.  Only two implies a rename/delete, and four implies a
 594         * rename/add.
 595         */
 596        struct stage_data *src_entry;
 597        struct stage_data *dst_entry;
 598        unsigned processed:1;
 599};
 600
 601static int update_stages(struct merge_options *opt, const char *path,
 602                         const struct diff_filespec *o,
 603                         const struct diff_filespec *a,
 604                         const struct diff_filespec *b)
 605{
 606
 607        /*
 608         * NOTE: It is usually a bad idea to call update_stages on a path
 609         * before calling update_file on that same path, since it can
 610         * sometimes lead to spurious "refusing to lose untracked file..."
 611         * messages from update_file (via make_room_for path via
 612         * would_lose_untracked).  Instead, reverse the order of the calls
 613         * (executing update_file first and then update_stages).
 614         */
 615        int clear = 1;
 616        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 617        if (clear)
 618                if (remove_file_from_cache(path))
 619                        return -1;
 620        if (o)
 621                if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
 622                        return -1;
 623        if (a)
 624                if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
 625                        return -1;
 626        if (b)
 627                if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
 628                        return -1;
 629        return 0;
 630}
 631
 632static void update_entry(struct stage_data *entry,
 633                         struct diff_filespec *o,
 634                         struct diff_filespec *a,
 635                         struct diff_filespec *b)
 636{
 637        entry->processed = 0;
 638        entry->stages[1].mode = o->mode;
 639        entry->stages[2].mode = a->mode;
 640        entry->stages[3].mode = b->mode;
 641        oidcpy(&entry->stages[1].oid, &o->oid);
 642        oidcpy(&entry->stages[2].oid, &a->oid);
 643        oidcpy(&entry->stages[3].oid, &b->oid);
 644}
 645
 646static int remove_file(struct merge_options *o, int clean,
 647                       const char *path, int no_wd)
 648{
 649        int update_cache = o->call_depth || clean;
 650        int update_working_directory = !o->call_depth && !no_wd;
 651
 652        if (update_cache) {
 653                if (remove_file_from_cache(path))
 654                        return -1;
 655        }
 656        if (update_working_directory) {
 657                if (ignore_case) {
 658                        struct cache_entry *ce;
 659                        ce = cache_file_exists(path, strlen(path), ignore_case);
 660                        if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
 661                                return 0;
 662                }
 663                if (remove_path(path))
 664                        return -1;
 665        }
 666        return 0;
 667}
 668
 669/* add a string to a strbuf, but converting "/" to "_" */
 670static void add_flattened_path(struct strbuf *out, const char *s)
 671{
 672        size_t i = out->len;
 673        strbuf_addstr(out, s);
 674        for (; i < out->len; i++)
 675                if (out->buf[i] == '/')
 676                        out->buf[i] = '_';
 677}
 678
 679static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 680{
 681        struct path_hashmap_entry *entry;
 682        struct strbuf newpath = STRBUF_INIT;
 683        int suffix = 0;
 684        size_t base_len;
 685
 686        strbuf_addf(&newpath, "%s~", path);
 687        add_flattened_path(&newpath, branch);
 688
 689        base_len = newpath.len;
 690        while (hashmap_get_from_hash(&o->current_file_dir_set,
 691                                     path_hash(newpath.buf), newpath.buf) ||
 692               (!o->call_depth && file_exists(newpath.buf))) {
 693                strbuf_setlen(&newpath, base_len);
 694                strbuf_addf(&newpath, "_%d", suffix++);
 695        }
 696
 697        FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
 698        hashmap_entry_init(entry, path_hash(entry->path));
 699        hashmap_add(&o->current_file_dir_set, entry);
 700        return strbuf_detach(&newpath, NULL);
 701}
 702
 703/**
 704 * Check whether a directory in the index is in the way of an incoming
 705 * file.  Return 1 if so.  If check_working_copy is non-zero, also
 706 * check the working directory.  If empty_ok is non-zero, also return
 707 * 0 in the case where the working-tree dir exists but is empty.
 708 */
 709static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
 710{
 711        int pos;
 712        struct strbuf dirpath = STRBUF_INIT;
 713        struct stat st;
 714
 715        strbuf_addstr(&dirpath, path);
 716        strbuf_addch(&dirpath, '/');
 717
 718        pos = cache_name_pos(dirpath.buf, dirpath.len);
 719
 720        if (pos < 0)
 721                pos = -1 - pos;
 722        if (pos < active_nr &&
 723            !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
 724                strbuf_release(&dirpath);
 725                return 1;
 726        }
 727
 728        strbuf_release(&dirpath);
 729        return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
 730                !(empty_ok && is_empty_dir(path));
 731}
 732
 733static int was_tracked(const char *path)
 734{
 735        int pos = cache_name_pos(path, strlen(path));
 736
 737        if (0 <= pos)
 738                /* we have been tracking this path */
 739                return 1;
 740
 741        /*
 742         * Look for an unmerged entry for the path,
 743         * specifically stage #2, which would indicate
 744         * that "our" side before the merge started
 745         * had the path tracked (and resulted in a conflict).
 746         */
 747        for (pos = -1 - pos;
 748             pos < active_nr && !strcmp(path, active_cache[pos]->name);
 749             pos++)
 750                if (ce_stage(active_cache[pos]) == 2)
 751                        return 1;
 752        return 0;
 753}
 754
 755static int would_lose_untracked(const char *path)
 756{
 757        return !was_tracked(path) && file_exists(path);
 758}
 759
 760static int make_room_for_path(struct merge_options *o, const char *path)
 761{
 762        int status, i;
 763        const char *msg = _("failed to create path '%s'%s");
 764
 765        /* Unlink any D/F conflict files that are in the way */
 766        for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 767                const char *df_path = o->df_conflict_file_set.items[i].string;
 768                size_t pathlen = strlen(path);
 769                size_t df_pathlen = strlen(df_path);
 770                if (df_pathlen < pathlen &&
 771                    path[df_pathlen] == '/' &&
 772                    strncmp(path, df_path, df_pathlen) == 0) {
 773                        output(o, 3,
 774                               _("Removing %s to make room for subdirectory\n"),
 775                               df_path);
 776                        unlink(df_path);
 777                        unsorted_string_list_delete_item(&o->df_conflict_file_set,
 778                                                         i, 0);
 779                        break;
 780                }
 781        }
 782
 783        /* Make sure leading directories are created */
 784        status = safe_create_leading_directories_const(path);
 785        if (status) {
 786                if (status == SCLD_EXISTS)
 787                        /* something else exists */
 788                        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 789                return err(o, msg, path, "");
 790        }
 791
 792        /*
 793         * Do not unlink a file in the work tree if we are not
 794         * tracking it.
 795         */
 796        if (would_lose_untracked(path))
 797                return err(o, _("refusing to lose untracked file at '%s'"),
 798                             path);
 799
 800        /* Successful unlink is good.. */
 801        if (!unlink(path))
 802                return 0;
 803        /* .. and so is no existing file */
 804        if (errno == ENOENT)
 805                return 0;
 806        /* .. but not some other error (who really cares what?) */
 807        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 808}
 809
 810static int update_file_flags(struct merge_options *o,
 811                             const struct object_id *oid,
 812                             unsigned mode,
 813                             const char *path,
 814                             int update_cache,
 815                             int update_wd)
 816{
 817        int ret = 0;
 818
 819        if (o->call_depth)
 820                update_wd = 0;
 821
 822        if (update_wd) {
 823                enum object_type type;
 824                void *buf;
 825                unsigned long size;
 826
 827                if (S_ISGITLINK(mode)) {
 828                        /*
 829                         * We may later decide to recursively descend into
 830                         * the submodule directory and update its index
 831                         * and/or work tree, but we do not do that now.
 832                         */
 833                        update_wd = 0;
 834                        goto update_index;
 835                }
 836
 837                buf = read_sha1_file(oid->hash, &type, &size);
 838                if (!buf)
 839                        return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 840                if (type != OBJ_BLOB) {
 841                        ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 842                        goto free_buf;
 843                }
 844                if (S_ISREG(mode)) {
 845                        struct strbuf strbuf = STRBUF_INIT;
 846                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 847                                free(buf);
 848                                size = strbuf.len;
 849                                buf = strbuf_detach(&strbuf, NULL);
 850                        }
 851                }
 852
 853                if (make_room_for_path(o, path) < 0) {
 854                        update_wd = 0;
 855                        goto free_buf;
 856                }
 857                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 858                        int fd;
 859                        if (mode & 0100)
 860                                mode = 0777;
 861                        else
 862                                mode = 0666;
 863                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 864                        if (fd < 0) {
 865                                ret = err(o, _("failed to open '%s': %s"),
 866                                          path, strerror(errno));
 867                                goto free_buf;
 868                        }
 869                        write_in_full(fd, buf, size);
 870                        close(fd);
 871                } else if (S_ISLNK(mode)) {
 872                        char *lnk = xmemdupz(buf, size);
 873                        safe_create_leading_directories_const(path);
 874                        unlink(path);
 875                        if (symlink(lnk, path))
 876                                ret = err(o, _("failed to symlink '%s': %s"),
 877                                        path, strerror(errno));
 878                        free(lnk);
 879                } else
 880                        ret = err(o,
 881                                  _("do not know what to do with %06o %s '%s'"),
 882                                  mode, oid_to_hex(oid), path);
 883 free_buf:
 884                free(buf);
 885        }
 886 update_index:
 887        if (!ret && update_cache)
 888                add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 889        return ret;
 890}
 891
 892static int update_file(struct merge_options *o,
 893                       int clean,
 894                       const struct object_id *oid,
 895                       unsigned mode,
 896                       const char *path)
 897{
 898        return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
 899}
 900
 901/* Low level file merging, update and removal */
 902
 903struct merge_file_info {
 904        struct object_id oid;
 905        unsigned mode;
 906        unsigned clean:1,
 907                 merge:1;
 908};
 909
 910static int merge_3way(struct merge_options *o,
 911                      mmbuffer_t *result_buf,
 912                      const struct diff_filespec *one,
 913                      const struct diff_filespec *a,
 914                      const struct diff_filespec *b,
 915                      const char *branch1,
 916                      const char *branch2)
 917{
 918        mmfile_t orig, src1, src2;
 919        struct ll_merge_options ll_opts = {0};
 920        char *base_name, *name1, *name2;
 921        int merge_status;
 922
 923        ll_opts.renormalize = o->renormalize;
 924        ll_opts.xdl_opts = o->xdl_opts;
 925
 926        if (o->call_depth) {
 927                ll_opts.virtual_ancestor = 1;
 928                ll_opts.variant = 0;
 929        } else {
 930                switch (o->recursive_variant) {
 931                case MERGE_RECURSIVE_OURS:
 932                        ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 933                        break;
 934                case MERGE_RECURSIVE_THEIRS:
 935                        ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 936                        break;
 937                default:
 938                        ll_opts.variant = 0;
 939                        break;
 940                }
 941        }
 942
 943        if (strcmp(a->path, b->path) ||
 944            (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 945                base_name = o->ancestor == NULL ? NULL :
 946                        mkpathdup("%s:%s", o->ancestor, one->path);
 947                name1 = mkpathdup("%s:%s", branch1, a->path);
 948                name2 = mkpathdup("%s:%s", branch2, b->path);
 949        } else {
 950                base_name = o->ancestor == NULL ? NULL :
 951                        mkpathdup("%s", o->ancestor);
 952                name1 = mkpathdup("%s", branch1);
 953                name2 = mkpathdup("%s", branch2);
 954        }
 955
 956        read_mmblob(&orig, &one->oid);
 957        read_mmblob(&src1, &a->oid);
 958        read_mmblob(&src2, &b->oid);
 959
 960        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 961                                &src1, name1, &src2, name2, &ll_opts);
 962
 963        free(base_name);
 964        free(name1);
 965        free(name2);
 966        free(orig.ptr);
 967        free(src1.ptr);
 968        free(src2.ptr);
 969        return merge_status;
 970}
 971
 972static int merge_file_1(struct merge_options *o,
 973                                           const struct diff_filespec *one,
 974                                           const struct diff_filespec *a,
 975                                           const struct diff_filespec *b,
 976                                           const char *branch1,
 977                                           const char *branch2,
 978                                           struct merge_file_info *result)
 979{
 980        result->merge = 0;
 981        result->clean = 1;
 982
 983        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 984                result->clean = 0;
 985                if (S_ISREG(a->mode)) {
 986                        result->mode = a->mode;
 987                        oidcpy(&result->oid, &a->oid);
 988                } else {
 989                        result->mode = b->mode;
 990                        oidcpy(&result->oid, &b->oid);
 991                }
 992        } else {
 993                if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
 994                        result->merge = 1;
 995
 996                /*
 997                 * Merge modes
 998                 */
 999                if (a->mode == b->mode || a->mode == one->mode)
1000                        result->mode = b->mode;
1001                else {
1002                        result->mode = a->mode;
1003                        if (b->mode != one->mode) {
1004                                result->clean = 0;
1005                                result->merge = 1;
1006                        }
1007                }
1008
1009                if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
1010                        oidcpy(&result->oid, &b->oid);
1011                else if (oid_eq(&b->oid, &one->oid))
1012                        oidcpy(&result->oid, &a->oid);
1013                else if (S_ISREG(a->mode)) {
1014                        mmbuffer_t result_buf;
1015                        int ret = 0, merge_status;
1016
1017                        merge_status = merge_3way(o, &result_buf, one, a, b,
1018                                                  branch1, branch2);
1019
1020                        if ((merge_status < 0) || !result_buf.ptr)
1021                                ret = err(o, _("Failed to execute internal merge"));
1022
1023                        if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
1024                                                    blob_type, result->oid.hash))
1025                                ret = err(o, _("Unable to add %s to database"),
1026                                          a->path);
1027
1028                        free(result_buf.ptr);
1029                        if (ret)
1030                                return ret;
1031                        result->clean = (merge_status == 0);
1032                } else if (S_ISGITLINK(a->mode)) {
1033                        result->clean = merge_submodule(&result->oid,
1034                                                       one->path,
1035                                                       &one->oid,
1036                                                       &a->oid,
1037                                                       &b->oid,
1038                                                       !o->call_depth);
1039                } else if (S_ISLNK(a->mode)) {
1040                        oidcpy(&result->oid, &a->oid);
1041
1042                        if (!oid_eq(&a->oid, &b->oid))
1043                                result->clean = 0;
1044                } else
1045                        die("BUG: unsupported object type in the tree");
1046        }
1047
1048        return 0;
1049}
1050
1051static int merge_file_special_markers(struct merge_options *o,
1052                           const struct diff_filespec *one,
1053                           const struct diff_filespec *a,
1054                           const struct diff_filespec *b,
1055                           const char *branch1,
1056                           const char *filename1,
1057                           const char *branch2,
1058                           const char *filename2,
1059                           struct merge_file_info *mfi)
1060{
1061        char *side1 = NULL;
1062        char *side2 = NULL;
1063        int ret;
1064
1065        if (filename1)
1066                side1 = xstrfmt("%s:%s", branch1, filename1);
1067        if (filename2)
1068                side2 = xstrfmt("%s:%s", branch2, filename2);
1069
1070        ret = merge_file_1(o, one, a, b,
1071                           side1 ? side1 : branch1,
1072                           side2 ? side2 : branch2, mfi);
1073        free(side1);
1074        free(side2);
1075        return ret;
1076}
1077
1078static int merge_file_one(struct merge_options *o,
1079                                         const char *path,
1080                                         const struct object_id *o_oid, int o_mode,
1081                                         const struct object_id *a_oid, int a_mode,
1082                                         const struct object_id *b_oid, int b_mode,
1083                                         const char *branch1,
1084                                         const char *branch2,
1085                                         struct merge_file_info *mfi)
1086{
1087        struct diff_filespec one, a, b;
1088
1089        one.path = a.path = b.path = (char *)path;
1090        oidcpy(&one.oid, o_oid);
1091        one.mode = o_mode;
1092        oidcpy(&a.oid, a_oid);
1093        a.mode = a_mode;
1094        oidcpy(&b.oid, b_oid);
1095        b.mode = b_mode;
1096        return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
1097}
1098
1099static int handle_change_delete(struct merge_options *o,
1100                                 const char *path, const char *old_path,
1101                                 const struct object_id *o_oid, int o_mode,
1102                                 const struct object_id *changed_oid,
1103                                 int changed_mode,
1104                                 const char *change_branch,
1105                                 const char *delete_branch,
1106                                 const char *change, const char *change_past)
1107{
1108        char *alt_path = NULL;
1109        const char *update_path = path;
1110        int ret = 0;
1111
1112        if (dir_in_way(path, !o->call_depth, 0)) {
1113                update_path = alt_path = unique_path(o, path, change_branch);
1114        }
1115
1116        if (o->call_depth) {
1117                /*
1118                 * We cannot arbitrarily accept either a_sha or b_sha as
1119                 * correct; since there is no true "middle point" between
1120                 * them, simply reuse the base version for virtual merge base.
1121                 */
1122                ret = remove_file_from_cache(path);
1123                if (!ret)
1124                        ret = update_file(o, 0, o_oid, o_mode, update_path);
1125        } else {
1126                if (!alt_path) {
1127                        if (!old_path) {
1128                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1129                                       "and %s in %s. Version %s of %s left in tree."),
1130                                       change, path, delete_branch, change_past,
1131                                       change_branch, change_branch, path);
1132                        } else {
1133                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1134                                       "and %s to %s in %s. Version %s of %s left in tree."),
1135                                       change, old_path, delete_branch, change_past, path,
1136                                       change_branch, change_branch, path);
1137                        }
1138                } else {
1139                        if (!old_path) {
1140                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1141                                       "and %s in %s. Version %s of %s left in tree at %s."),
1142                                       change, path, delete_branch, change_past,
1143                                       change_branch, change_branch, path, alt_path);
1144                        } else {
1145                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1146                                       "and %s to %s in %s. Version %s of %s left in tree at %s."),
1147                                       change, old_path, delete_branch, change_past, path,
1148                                       change_branch, change_branch, path, alt_path);
1149                        }
1150                }
1151                /*
1152                 * No need to call update_file() on path when change_branch ==
1153                 * o->branch1 && !alt_path, since that would needlessly touch
1154                 * path.  We could call update_file_flags() with update_cache=0
1155                 * and update_wd=0, but that's a no-op.
1156                 */
1157                if (change_branch != o->branch1 || alt_path)
1158                        ret = update_file(o, 0, changed_oid, changed_mode, update_path);
1159        }
1160        free(alt_path);
1161
1162        return ret;
1163}
1164
1165static int conflict_rename_delete(struct merge_options *o,
1166                                   struct diff_filepair *pair,
1167                                   const char *rename_branch,
1168                                   const char *delete_branch)
1169{
1170        const struct diff_filespec *orig = pair->one;
1171        const struct diff_filespec *dest = pair->two;
1172
1173        if (handle_change_delete(o,
1174                                 o->call_depth ? orig->path : dest->path,
1175                                 o->call_depth ? NULL : orig->path,
1176                                 &orig->oid, orig->mode,
1177                                 &dest->oid, dest->mode,
1178                                 rename_branch, delete_branch,
1179                                 _("rename"), _("renamed")))
1180                return -1;
1181
1182        if (o->call_depth)
1183                return remove_file_from_cache(dest->path);
1184        else
1185                return update_stages(o, dest->path, NULL,
1186                                     rename_branch == o->branch1 ? dest : NULL,
1187                                     rename_branch == o->branch1 ? NULL : dest);
1188}
1189
1190static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1191                                                 struct stage_data *entry,
1192                                                 int stage)
1193{
1194        struct object_id *oid = &entry->stages[stage].oid;
1195        unsigned mode = entry->stages[stage].mode;
1196        if (mode == 0 || is_null_oid(oid))
1197                return NULL;
1198        oidcpy(&target->oid, oid);
1199        target->mode = mode;
1200        return target;
1201}
1202
1203static int handle_file(struct merge_options *o,
1204                        struct diff_filespec *rename,
1205                        int stage,
1206                        struct rename_conflict_info *ci)
1207{
1208        char *dst_name = rename->path;
1209        struct stage_data *dst_entry;
1210        const char *cur_branch, *other_branch;
1211        struct diff_filespec other;
1212        struct diff_filespec *add;
1213        int ret;
1214
1215        if (stage == 2) {
1216                dst_entry = ci->dst_entry1;
1217                cur_branch = ci->branch1;
1218                other_branch = ci->branch2;
1219        } else {
1220                dst_entry = ci->dst_entry2;
1221                cur_branch = ci->branch2;
1222                other_branch = ci->branch1;
1223        }
1224
1225        add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1226        if (add) {
1227                char *add_name = unique_path(o, rename->path, other_branch);
1228                if (update_file(o, 0, &add->oid, add->mode, add_name))
1229                        return -1;
1230
1231                remove_file(o, 0, rename->path, 0);
1232                dst_name = unique_path(o, rename->path, cur_branch);
1233        } else {
1234                if (dir_in_way(rename->path, !o->call_depth, 0)) {
1235                        dst_name = unique_path(o, rename->path, cur_branch);
1236                        output(o, 1, _("%s is a directory in %s adding as %s instead"),
1237                               rename->path, other_branch, dst_name);
1238                }
1239        }
1240        if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
1241                ; /* fall through, do allow dst_name to be released */
1242        else if (stage == 2)
1243                ret = update_stages(o, rename->path, NULL, rename, add);
1244        else
1245                ret = update_stages(o, rename->path, NULL, add, rename);
1246
1247        if (dst_name != rename->path)
1248                free(dst_name);
1249
1250        return ret;
1251}
1252
1253static int conflict_rename_rename_1to2(struct merge_options *o,
1254                                        struct rename_conflict_info *ci)
1255{
1256        /* One file was renamed in both branches, but to different names. */
1257        struct diff_filespec *one = ci->pair1->one;
1258        struct diff_filespec *a = ci->pair1->two;
1259        struct diff_filespec *b = ci->pair2->two;
1260
1261        output(o, 1, _("CONFLICT (rename/rename): "
1262               "Rename \"%s\"->\"%s\" in branch \"%s\" "
1263               "rename \"%s\"->\"%s\" in \"%s\"%s"),
1264               one->path, a->path, ci->branch1,
1265               one->path, b->path, ci->branch2,
1266               o->call_depth ? _(" (left unresolved)") : "");
1267        if (o->call_depth) {
1268                struct merge_file_info mfi;
1269                struct diff_filespec other;
1270                struct diff_filespec *add;
1271                if (merge_file_one(o, one->path,
1272                                 &one->oid, one->mode,
1273                                 &a->oid, a->mode,
1274                                 &b->oid, b->mode,
1275                                 ci->branch1, ci->branch2, &mfi))
1276                        return -1;
1277
1278                /*
1279                 * FIXME: For rename/add-source conflicts (if we could detect
1280                 * such), this is wrong.  We should instead find a unique
1281                 * pathname and then either rename the add-source file to that
1282                 * unique path, or use that unique path instead of src here.
1283                 */
1284                if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
1285                        return -1;
1286
1287                /*
1288                 * Above, we put the merged content at the merge-base's
1289                 * path.  Now we usually need to delete both a->path and
1290                 * b->path.  However, the rename on each side of the merge
1291                 * could also be involved in a rename/add conflict.  In
1292                 * such cases, we should keep the added file around,
1293                 * resolving the conflict at that path in its favor.
1294                 */
1295                add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1296                if (add) {
1297                        if (update_file(o, 0, &add->oid, add->mode, a->path))
1298                                return -1;
1299                }
1300                else
1301                        remove_file_from_cache(a->path);
1302                add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1303                if (add) {
1304                        if (update_file(o, 0, &add->oid, add->mode, b->path))
1305                                return -1;
1306                }
1307                else
1308                        remove_file_from_cache(b->path);
1309        } else if (handle_file(o, a, 2, ci) || handle_file(o, b, 3, ci))
1310                return -1;
1311
1312        return 0;
1313}
1314
1315static int conflict_rename_rename_2to1(struct merge_options *o,
1316                                        struct rename_conflict_info *ci)
1317{
1318        /* Two files, a & b, were renamed to the same thing, c. */
1319        struct diff_filespec *a = ci->pair1->one;
1320        struct diff_filespec *b = ci->pair2->one;
1321        struct diff_filespec *c1 = ci->pair1->two;
1322        struct diff_filespec *c2 = ci->pair2->two;
1323        char *path = c1->path; /* == c2->path */
1324        struct merge_file_info mfi_c1;
1325        struct merge_file_info mfi_c2;
1326        int ret;
1327
1328        output(o, 1, _("CONFLICT (rename/rename): "
1329               "Rename %s->%s in %s. "
1330               "Rename %s->%s in %s"),
1331               a->path, c1->path, ci->branch1,
1332               b->path, c2->path, ci->branch2);
1333
1334        remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1335        remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1336
1337        if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
1338                                       o->branch1, c1->path,
1339                                       o->branch2, ci->ren1_other.path, &mfi_c1) ||
1340            merge_file_special_markers(o, b, &ci->ren2_other, c2,
1341                                       o->branch1, ci->ren2_other.path,
1342                                       o->branch2, c2->path, &mfi_c2))
1343                return -1;
1344
1345        if (o->call_depth) {
1346                /*
1347                 * If mfi_c1.clean && mfi_c2.clean, then it might make
1348                 * sense to do a two-way merge of those results.  But, I
1349                 * think in all cases, it makes sense to have the virtual
1350                 * merge base just undo the renames; they can be detected
1351                 * again later for the non-recursive merge.
1352                 */
1353                remove_file(o, 0, path, 0);
1354                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, a->path);
1355                if (!ret)
1356                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1357                                          b->path);
1358        } else {
1359                char *new_path1 = unique_path(o, path, ci->branch1);
1360                char *new_path2 = unique_path(o, path, ci->branch2);
1361                output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1362                       a->path, new_path1, b->path, new_path2);
1363                remove_file(o, 0, path, 0);
1364                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
1365                if (!ret)
1366                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1367                                          new_path2);
1368                free(new_path2);
1369                free(new_path1);
1370        }
1371
1372        return ret;
1373}
1374
1375/*
1376 * Get the diff_filepairs changed between o_tree and tree.
1377 */
1378static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
1379                                               struct tree *o_tree,
1380                                               struct tree *tree)
1381{
1382        struct diff_queue_struct *ret;
1383        struct diff_options opts;
1384
1385        diff_setup(&opts);
1386        opts.flags.recursive = 1;
1387        opts.flags.rename_empty = 0;
1388        opts.detect_rename = DIFF_DETECT_RENAME;
1389        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
1390                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
1391                            1000;
1392        opts.rename_score = o->rename_score;
1393        opts.show_rename_progress = o->show_rename_progress;
1394        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1395        diff_setup_done(&opts);
1396        diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
1397        diffcore_std(&opts);
1398        if (opts.needed_rename_limit > o->needed_rename_limit)
1399                o->needed_rename_limit = opts.needed_rename_limit;
1400
1401        ret = xmalloc(sizeof(*ret));
1402        *ret = diff_queued_diff;
1403
1404        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1405        diff_queued_diff.nr = 0;
1406        diff_queued_diff.queue = NULL;
1407        diff_flush(&opts);
1408        return ret;
1409}
1410
1411static int tree_has_path(struct tree *tree, const char *path)
1412{
1413        unsigned char hashy[GIT_MAX_RAWSZ];
1414        unsigned int mode_o;
1415
1416        return !get_tree_entry(tree->object.oid.hash, path,
1417                               hashy, &mode_o);
1418}
1419
1420/*
1421 * Return a new string that replaces the beginning portion (which matches
1422 * entry->dir), with entry->new_dir.  In perl-speak:
1423 *   new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
1424 * NOTE:
1425 *   Caller must ensure that old_path starts with entry->dir + '/'.
1426 */
1427static char *apply_dir_rename(struct dir_rename_entry *entry,
1428                              const char *old_path)
1429{
1430        struct strbuf new_path = STRBUF_INIT;
1431        int oldlen, newlen;
1432
1433        if (entry->non_unique_new_dir)
1434                return NULL;
1435
1436        oldlen = strlen(entry->dir);
1437        newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
1438        strbuf_grow(&new_path, newlen);
1439        strbuf_addbuf(&new_path, &entry->new_dir);
1440        strbuf_addstr(&new_path, &old_path[oldlen]);
1441
1442        return strbuf_detach(&new_path, NULL);
1443}
1444
1445static void get_renamed_dir_portion(const char *old_path, const char *new_path,
1446                                    char **old_dir, char **new_dir)
1447{
1448        char *end_of_old, *end_of_new;
1449        int old_len, new_len;
1450
1451        *old_dir = NULL;
1452        *new_dir = NULL;
1453
1454        /*
1455         * For
1456         *    "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
1457         * the "e/foo.c" part is the same, we just want to know that
1458         *    "a/b/c/d" was renamed to "a/b/some/thing/else"
1459         * so, for this example, this function returns "a/b/c/d" in
1460         * *old_dir and "a/b/some/thing/else" in *new_dir.
1461         *
1462         * Also, if the basename of the file changed, we don't care.  We
1463         * want to know which portion of the directory, if any, changed.
1464         */
1465        end_of_old = strrchr(old_path, '/');
1466        end_of_new = strrchr(new_path, '/');
1467
1468        if (end_of_old == NULL || end_of_new == NULL)
1469                return;
1470        while (*--end_of_new == *--end_of_old &&
1471               end_of_old != old_path &&
1472               end_of_new != new_path)
1473                ; /* Do nothing; all in the while loop */
1474        /*
1475         * We've found the first non-matching character in the directory
1476         * paths.  That means the current directory we were comparing
1477         * represents the rename.  Move end_of_old and end_of_new back
1478         * to the full directory name.
1479         */
1480        if (*end_of_old == '/')
1481                end_of_old++;
1482        if (*end_of_old != '/')
1483                end_of_new++;
1484        end_of_old = strchr(end_of_old, '/');
1485        end_of_new = strchr(end_of_new, '/');
1486
1487        /*
1488         * It may have been the case that old_path and new_path were the same
1489         * directory all along.  Don't claim a rename if they're the same.
1490         */
1491        old_len = end_of_old - old_path;
1492        new_len = end_of_new - new_path;
1493
1494        if (old_len != new_len || strncmp(old_path, new_path, old_len)) {
1495                *old_dir = xstrndup(old_path, old_len);
1496                *new_dir = xstrndup(new_path, new_len);
1497        }
1498}
1499
1500static void remove_hashmap_entries(struct hashmap *dir_renames,
1501                                   struct string_list *items_to_remove)
1502{
1503        int i;
1504        struct dir_rename_entry *entry;
1505
1506        for (i = 0; i < items_to_remove->nr; i++) {
1507                entry = items_to_remove->items[i].util;
1508                hashmap_remove(dir_renames, entry, NULL);
1509        }
1510        string_list_clear(items_to_remove, 0);
1511}
1512
1513/*
1514 * There are a couple things we want to do at the directory level:
1515 *   1. Check for both sides renaming to the same thing, in order to avoid
1516 *      implicit renaming of files that should be left in place.  (See
1517 *      testcase 6b in t6043 for details.)
1518 *   2. Prune directory renames if there are still files left in the
1519 *      the original directory.  These represent a partial directory rename,
1520 *      i.e. a rename where only some of the files within the directory
1521 *      were renamed elsewhere.  (Technically, this could be done earlier
1522 *      in get_directory_renames(), except that would prevent us from
1523 *      doing the previous check and thus failing testcase 6b.)
1524 *   3. Check for rename/rename(1to2) conflicts (at the directory level).
1525 *      In the future, we could potentially record this info as well and
1526 *      omit reporting rename/rename(1to2) conflicts for each path within
1527 *      the affected directories, thus cleaning up the merge output.
1528 *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
1529 *         directory level, because merging directories is fine.  If it
1530 *         causes conflicts for files within those merged directories, then
1531 *         that should be detected at the individual path level.
1532 */
1533static void handle_directory_level_conflicts(struct merge_options *o,
1534                                             struct hashmap *dir_re_head,
1535                                             struct tree *head,
1536                                             struct hashmap *dir_re_merge,
1537                                             struct tree *merge)
1538{
1539        struct hashmap_iter iter;
1540        struct dir_rename_entry *head_ent;
1541        struct dir_rename_entry *merge_ent;
1542
1543        struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
1544        struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
1545
1546        hashmap_iter_init(dir_re_head, &iter);
1547        while ((head_ent = hashmap_iter_next(&iter))) {
1548                merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
1549                if (merge_ent &&
1550                    !head_ent->non_unique_new_dir &&
1551                    !merge_ent->non_unique_new_dir &&
1552                    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
1553                        /* 1. Renamed identically; remove it from both sides */
1554                        string_list_append(&remove_from_head,
1555                                           head_ent->dir)->util = head_ent;
1556                        strbuf_release(&head_ent->new_dir);
1557                        string_list_append(&remove_from_merge,
1558                                           merge_ent->dir)->util = merge_ent;
1559                        strbuf_release(&merge_ent->new_dir);
1560                } else if (tree_has_path(head, head_ent->dir)) {
1561                        /* 2. This wasn't a directory rename after all */
1562                        string_list_append(&remove_from_head,
1563                                           head_ent->dir)->util = head_ent;
1564                        strbuf_release(&head_ent->new_dir);
1565                }
1566        }
1567
1568        remove_hashmap_entries(dir_re_head, &remove_from_head);
1569        remove_hashmap_entries(dir_re_merge, &remove_from_merge);
1570
1571        hashmap_iter_init(dir_re_merge, &iter);
1572        while ((merge_ent = hashmap_iter_next(&iter))) {
1573                head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
1574                if (tree_has_path(merge, merge_ent->dir)) {
1575                        /* 2. This wasn't a directory rename after all */
1576                        string_list_append(&remove_from_merge,
1577                                           merge_ent->dir)->util = merge_ent;
1578                } else if (head_ent &&
1579                           !head_ent->non_unique_new_dir &&
1580                           !merge_ent->non_unique_new_dir) {
1581                        /* 3. rename/rename(1to2) */
1582                        /*
1583                         * We can assume it's not rename/rename(1to1) because
1584                         * that was case (1), already checked above.  So we
1585                         * know that head_ent->new_dir and merge_ent->new_dir
1586                         * are different strings.
1587                         */
1588                        output(o, 1, _("CONFLICT (rename/rename): "
1589                                       "Rename directory %s->%s in %s. "
1590                                       "Rename directory %s->%s in %s"),
1591                               head_ent->dir, head_ent->new_dir.buf, o->branch1,
1592                               head_ent->dir, merge_ent->new_dir.buf, o->branch2);
1593                        string_list_append(&remove_from_head,
1594                                           head_ent->dir)->util = head_ent;
1595                        strbuf_release(&head_ent->new_dir);
1596                        string_list_append(&remove_from_merge,
1597                                           merge_ent->dir)->util = merge_ent;
1598                        strbuf_release(&merge_ent->new_dir);
1599                }
1600        }
1601
1602        remove_hashmap_entries(dir_re_head, &remove_from_head);
1603        remove_hashmap_entries(dir_re_merge, &remove_from_merge);
1604}
1605
1606static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
1607                                             struct tree *tree)
1608{
1609        struct hashmap *dir_renames;
1610        struct hashmap_iter iter;
1611        struct dir_rename_entry *entry;
1612        int i;
1613
1614        /*
1615         * Typically, we think of a directory rename as all files from a
1616         * certain directory being moved to a target directory.  However,
1617         * what if someone first moved two files from the original
1618         * directory in one commit, and then renamed the directory
1619         * somewhere else in a later commit?  At merge time, we just know
1620         * that files from the original directory went to two different
1621         * places, and that the bulk of them ended up in the same place.
1622         * We want each directory rename to represent where the bulk of the
1623         * files from that directory end up; this function exists to find
1624         * where the bulk of the files went.
1625         *
1626         * The first loop below simply iterates through the list of file
1627         * renames, finding out how often each directory rename pair
1628         * possibility occurs.
1629         */
1630        dir_renames = xmalloc(sizeof(struct hashmap));
1631        dir_rename_init(dir_renames);
1632        for (i = 0; i < pairs->nr; ++i) {
1633                struct string_list_item *item;
1634                int *count;
1635                struct diff_filepair *pair = pairs->queue[i];
1636                char *old_dir, *new_dir;
1637
1638                /* File not part of directory rename if it wasn't renamed */
1639                if (pair->status != 'R')
1640                        continue;
1641
1642                get_renamed_dir_portion(pair->one->path, pair->two->path,
1643                                        &old_dir,        &new_dir);
1644                if (!old_dir)
1645                        /* Directory didn't change at all; ignore this one. */
1646                        continue;
1647
1648                entry = dir_rename_find_entry(dir_renames, old_dir);
1649                if (!entry) {
1650                        entry = xmalloc(sizeof(struct dir_rename_entry));
1651                        dir_rename_entry_init(entry, old_dir);
1652                        hashmap_put(dir_renames, entry);
1653                } else {
1654                        free(old_dir);
1655                }
1656                item = string_list_lookup(&entry->possible_new_dirs, new_dir);
1657                if (!item) {
1658                        item = string_list_insert(&entry->possible_new_dirs,
1659                                                  new_dir);
1660                        item->util = xcalloc(1, sizeof(int));
1661                } else {
1662                        free(new_dir);
1663                }
1664                count = item->util;
1665                *count += 1;
1666        }
1667
1668        /*
1669         * For each directory with files moved out of it, we find out which
1670         * target directory received the most files so we can declare it to
1671         * be the "winning" target location for the directory rename.  This
1672         * winner gets recorded in new_dir.  If there is no winner
1673         * (multiple target directories received the same number of files),
1674         * we set non_unique_new_dir.  Once we've determined the winner (or
1675         * that there is no winner), we no longer need possible_new_dirs.
1676         */
1677        hashmap_iter_init(dir_renames, &iter);
1678        while ((entry = hashmap_iter_next(&iter))) {
1679                int max = 0;
1680                int bad_max = 0;
1681                char *best = NULL;
1682
1683                for (i = 0; i < entry->possible_new_dirs.nr; i++) {
1684                        int *count = entry->possible_new_dirs.items[i].util;
1685
1686                        if (*count == max)
1687                                bad_max = max;
1688                        else if (*count > max) {
1689                                max = *count;
1690                                best = entry->possible_new_dirs.items[i].string;
1691                        }
1692                }
1693                if (bad_max == max)
1694                        entry->non_unique_new_dir = 1;
1695                else {
1696                        assert(entry->new_dir.len == 0);
1697                        strbuf_addstr(&entry->new_dir, best);
1698                }
1699                /*
1700                 * The relevant directory sub-portion of the original full
1701                 * filepaths were xstrndup'ed before inserting into
1702                 * possible_new_dirs, and instead of manually iterating the
1703                 * list and free'ing each, just lie and tell
1704                 * possible_new_dirs that it did the strdup'ing so that it
1705                 * will free them for us.
1706                 */
1707                entry->possible_new_dirs.strdup_strings = 1;
1708                string_list_clear(&entry->possible_new_dirs, 1);
1709        }
1710
1711        return dir_renames;
1712}
1713
1714static struct dir_rename_entry *check_dir_renamed(const char *path,
1715                                                  struct hashmap *dir_renames)
1716{
1717        char temp[PATH_MAX];
1718        char *end;
1719        struct dir_rename_entry *entry;
1720
1721        strcpy(temp, path);
1722        while ((end = strrchr(temp, '/'))) {
1723                *end = '\0';
1724                entry = dir_rename_find_entry(dir_renames, temp);
1725                if (entry)
1726                        return entry;
1727        }
1728        return NULL;
1729}
1730
1731static void compute_collisions(struct hashmap *collisions,
1732                               struct hashmap *dir_renames,
1733                               struct diff_queue_struct *pairs)
1734{
1735        int i;
1736
1737        /*
1738         * Multiple files can be mapped to the same path due to directory
1739         * renames done by the other side of history.  Since that other
1740         * side of history could have merged multiple directories into one,
1741         * if our side of history added the same file basename to each of
1742         * those directories, then all N of them would get implicitly
1743         * renamed by the directory rename detection into the same path,
1744         * and we'd get an add/add/.../add conflict, and all those adds
1745         * from *this* side of history.  This is not representable in the
1746         * index, and users aren't going to easily be able to make sense of
1747         * it.  So we need to provide a good warning about what's
1748         * happening, and fall back to no-directory-rename detection
1749         * behavior for those paths.
1750         *
1751         * See testcases 9e and all of section 5 from t6043 for examples.
1752         */
1753        collision_init(collisions);
1754
1755        for (i = 0; i < pairs->nr; ++i) {
1756                struct dir_rename_entry *dir_rename_ent;
1757                struct collision_entry *collision_ent;
1758                char *new_path;
1759                struct diff_filepair *pair = pairs->queue[i];
1760
1761                if (pair->status == 'D')
1762                        continue;
1763                dir_rename_ent = check_dir_renamed(pair->two->path,
1764                                                   dir_renames);
1765                if (!dir_rename_ent)
1766                        continue;
1767
1768                new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
1769                if (!new_path)
1770                        /*
1771                         * dir_rename_ent->non_unique_new_path is true, which
1772                         * means there is no directory rename for us to use,
1773                         * which means it won't cause us any additional
1774                         * collisions.
1775                         */
1776                        continue;
1777                collision_ent = collision_find_entry(collisions, new_path);
1778                if (!collision_ent) {
1779                        collision_ent = xcalloc(1,
1780                                                sizeof(struct collision_entry));
1781                        hashmap_entry_init(collision_ent, strhash(new_path));
1782                        hashmap_put(collisions, collision_ent);
1783                        collision_ent->target_file = new_path;
1784                } else {
1785                        free(new_path);
1786                }
1787                string_list_insert(&collision_ent->source_files,
1788                                   pair->two->path);
1789        }
1790}
1791
1792/*
1793 * Get information of all renames which occurred in 'pairs', making use of
1794 * any implicit directory renames inferred from the other side of history.
1795 * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
1796 * to be able to associate the correct cache entries with the rename
1797 * information; tree is always equal to either a_tree or b_tree.
1798 */
1799static struct string_list *get_renames(struct merge_options *o,
1800                                       struct diff_queue_struct *pairs,
1801                                       struct hashmap *dir_renames,
1802                                       struct tree *tree,
1803                                       struct tree *o_tree,
1804                                       struct tree *a_tree,
1805                                       struct tree *b_tree,
1806                                       struct string_list *entries)
1807{
1808        int i;
1809        struct hashmap collisions;
1810        struct hashmap_iter iter;
1811        struct collision_entry *e;
1812        struct string_list *renames;
1813
1814        compute_collisions(&collisions, dir_renames, pairs);
1815        renames = xcalloc(1, sizeof(struct string_list));
1816
1817        for (i = 0; i < pairs->nr; ++i) {
1818                struct string_list_item *item;
1819                struct rename *re;
1820                struct diff_filepair *pair = pairs->queue[i];
1821
1822                if (pair->status != 'R') {
1823                        diff_free_filepair(pair);
1824                        continue;
1825                }
1826                re = xmalloc(sizeof(*re));
1827                re->processed = 0;
1828                re->pair = pair;
1829                item = string_list_lookup(entries, re->pair->one->path);
1830                if (!item)
1831                        re->src_entry = insert_stage_data(re->pair->one->path,
1832                                        o_tree, a_tree, b_tree, entries);
1833                else
1834                        re->src_entry = item->util;
1835
1836                item = string_list_lookup(entries, re->pair->two->path);
1837                if (!item)
1838                        re->dst_entry = insert_stage_data(re->pair->two->path,
1839                                        o_tree, a_tree, b_tree, entries);
1840                else
1841                        re->dst_entry = item->util;
1842                item = string_list_insert(renames, pair->one->path);
1843                item->util = re;
1844        }
1845
1846        hashmap_iter_init(&collisions, &iter);
1847        while ((e = hashmap_iter_next(&iter))) {
1848                free(e->target_file);
1849                string_list_clear(&e->source_files, 0);
1850        }
1851        hashmap_free(&collisions, 1);
1852        return renames;
1853}
1854
1855static int process_renames(struct merge_options *o,
1856                           struct string_list *a_renames,
1857                           struct string_list *b_renames)
1858{
1859        int clean_merge = 1, i, j;
1860        struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1861        struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1862        const struct rename *sre;
1863
1864        for (i = 0; i < a_renames->nr; i++) {
1865                sre = a_renames->items[i].util;
1866                string_list_insert(&a_by_dst, sre->pair->two->path)->util
1867                        = (void *)sre;
1868        }
1869        for (i = 0; i < b_renames->nr; i++) {
1870                sre = b_renames->items[i].util;
1871                string_list_insert(&b_by_dst, sre->pair->two->path)->util
1872                        = (void *)sre;
1873        }
1874
1875        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1876                struct string_list *renames1, *renames2Dst;
1877                struct rename *ren1 = NULL, *ren2 = NULL;
1878                const char *branch1, *branch2;
1879                const char *ren1_src, *ren1_dst;
1880                struct string_list_item *lookup;
1881
1882                if (i >= a_renames->nr) {
1883                        ren2 = b_renames->items[j++].util;
1884                } else if (j >= b_renames->nr) {
1885                        ren1 = a_renames->items[i++].util;
1886                } else {
1887                        int compare = strcmp(a_renames->items[i].string,
1888                                             b_renames->items[j].string);
1889                        if (compare <= 0)
1890                                ren1 = a_renames->items[i++].util;
1891                        if (compare >= 0)
1892                                ren2 = b_renames->items[j++].util;
1893                }
1894
1895                /* TODO: refactor, so that 1/2 are not needed */
1896                if (ren1) {
1897                        renames1 = a_renames;
1898                        renames2Dst = &b_by_dst;
1899                        branch1 = o->branch1;
1900                        branch2 = o->branch2;
1901                } else {
1902                        renames1 = b_renames;
1903                        renames2Dst = &a_by_dst;
1904                        branch1 = o->branch2;
1905                        branch2 = o->branch1;
1906                        SWAP(ren2, ren1);
1907                }
1908
1909                if (ren1->processed)
1910                        continue;
1911                ren1->processed = 1;
1912                ren1->dst_entry->processed = 1;
1913                /* BUG: We should only mark src_entry as processed if we
1914                 * are not dealing with a rename + add-source case.
1915                 */
1916                ren1->src_entry->processed = 1;
1917
1918                ren1_src = ren1->pair->one->path;
1919                ren1_dst = ren1->pair->two->path;
1920
1921                if (ren2) {
1922                        /* One file renamed on both sides */
1923                        const char *ren2_src = ren2->pair->one->path;
1924                        const char *ren2_dst = ren2->pair->two->path;
1925                        enum rename_type rename_type;
1926                        if (strcmp(ren1_src, ren2_src) != 0)
1927                                die("BUG: ren1_src != ren2_src");
1928                        ren2->dst_entry->processed = 1;
1929                        ren2->processed = 1;
1930                        if (strcmp(ren1_dst, ren2_dst) != 0) {
1931                                rename_type = RENAME_ONE_FILE_TO_TWO;
1932                                clean_merge = 0;
1933                        } else {
1934                                rename_type = RENAME_ONE_FILE_TO_ONE;
1935                                /* BUG: We should only remove ren1_src in
1936                                 * the base stage (think of rename +
1937                                 * add-source cases).
1938                                 */
1939                                remove_file(o, 1, ren1_src, 1);
1940                                update_entry(ren1->dst_entry,
1941                                             ren1->pair->one,
1942                                             ren1->pair->two,
1943                                             ren2->pair->two);
1944                        }
1945                        setup_rename_conflict_info(rename_type,
1946                                                   ren1->pair,
1947                                                   ren2->pair,
1948                                                   branch1,
1949                                                   branch2,
1950                                                   ren1->dst_entry,
1951                                                   ren2->dst_entry,
1952                                                   o,
1953                                                   NULL,
1954                                                   NULL);
1955                } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1956                        /* Two different files renamed to the same thing */
1957                        char *ren2_dst;
1958                        ren2 = lookup->util;
1959                        ren2_dst = ren2->pair->two->path;
1960                        if (strcmp(ren1_dst, ren2_dst) != 0)
1961                                die("BUG: ren1_dst != ren2_dst");
1962
1963                        clean_merge = 0;
1964                        ren2->processed = 1;
1965                        /*
1966                         * BUG: We should only mark src_entry as processed
1967                         * if we are not dealing with a rename + add-source
1968                         * case.
1969                         */
1970                        ren2->src_entry->processed = 1;
1971
1972                        setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1973                                                   ren1->pair,
1974                                                   ren2->pair,
1975                                                   branch1,
1976                                                   branch2,
1977                                                   ren1->dst_entry,
1978                                                   ren2->dst_entry,
1979                                                   o,
1980                                                   ren1->src_entry,
1981                                                   ren2->src_entry);
1982
1983                } else {
1984                        /* Renamed in 1, maybe changed in 2 */
1985                        /* we only use sha1 and mode of these */
1986                        struct diff_filespec src_other, dst_other;
1987                        int try_merge;
1988
1989                        /*
1990                         * unpack_trees loads entries from common-commit
1991                         * into stage 1, from head-commit into stage 2, and
1992                         * from merge-commit into stage 3.  We keep track
1993                         * of which side corresponds to the rename.
1994                         */
1995                        int renamed_stage = a_renames == renames1 ? 2 : 3;
1996                        int other_stage =   a_renames == renames1 ? 3 : 2;
1997
1998                        /* BUG: We should only remove ren1_src in the base
1999                         * stage and in other_stage (think of rename +
2000                         * add-source case).
2001                         */
2002                        remove_file(o, 1, ren1_src,
2003                                    renamed_stage == 2 || !was_tracked(ren1_src));
2004
2005                        oidcpy(&src_other.oid,
2006                               &ren1->src_entry->stages[other_stage].oid);
2007                        src_other.mode = ren1->src_entry->stages[other_stage].mode;
2008                        oidcpy(&dst_other.oid,
2009                               &ren1->dst_entry->stages[other_stage].oid);
2010                        dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
2011                        try_merge = 0;
2012
2013                        if (oid_eq(&src_other.oid, &null_oid)) {
2014                                setup_rename_conflict_info(RENAME_DELETE,
2015                                                           ren1->pair,
2016                                                           NULL,
2017                                                           branch1,
2018                                                           branch2,
2019                                                           ren1->dst_entry,
2020                                                           NULL,
2021                                                           o,
2022                                                           NULL,
2023                                                           NULL);
2024                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
2025                                   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
2026                                /*
2027                                 * Added file on the other side identical to
2028                                 * the file being renamed: clean merge.
2029                                 * Also, there is no need to overwrite the
2030                                 * file already in the working copy, so call
2031                                 * update_file_flags() instead of
2032                                 * update_file().
2033                                 */
2034                                if (update_file_flags(o,
2035                                                      &ren1->pair->two->oid,
2036                                                      ren1->pair->two->mode,
2037                                                      ren1_dst,
2038                                                      1, /* update_cache */
2039                                                      0  /* update_wd    */))
2040                                        clean_merge = -1;
2041                        } else if (!oid_eq(&dst_other.oid, &null_oid)) {
2042                                clean_merge = 0;
2043                                try_merge = 1;
2044                                output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
2045                                       "%s added in %s"),
2046                                       ren1_src, ren1_dst, branch1,
2047                                       ren1_dst, branch2);
2048                                if (o->call_depth) {
2049                                        struct merge_file_info mfi;
2050                                        if (merge_file_one(o, ren1_dst, &null_oid, 0,
2051                                                           &ren1->pair->two->oid,
2052                                                           ren1->pair->two->mode,
2053                                                           &dst_other.oid,
2054                                                           dst_other.mode,
2055                                                           branch1, branch2, &mfi)) {
2056                                                clean_merge = -1;
2057                                                goto cleanup_and_return;
2058                                        }
2059                                        output(o, 1, _("Adding merged %s"), ren1_dst);
2060                                        if (update_file(o, 0, &mfi.oid,
2061                                                        mfi.mode, ren1_dst))
2062                                                clean_merge = -1;
2063                                        try_merge = 0;
2064                                } else {
2065                                        char *new_path = unique_path(o, ren1_dst, branch2);
2066                                        output(o, 1, _("Adding as %s instead"), new_path);
2067                                        if (update_file(o, 0, &dst_other.oid,
2068                                                        dst_other.mode, new_path))
2069                                                clean_merge = -1;
2070                                        free(new_path);
2071                                }
2072                        } else
2073                                try_merge = 1;
2074
2075                        if (clean_merge < 0)
2076                                goto cleanup_and_return;
2077                        if (try_merge) {
2078                                struct diff_filespec *one, *a, *b;
2079                                src_other.path = (char *)ren1_src;
2080
2081                                one = ren1->pair->one;
2082                                if (a_renames == renames1) {
2083                                        a = ren1->pair->two;
2084                                        b = &src_other;
2085                                } else {
2086                                        b = ren1->pair->two;
2087                                        a = &src_other;
2088                                }
2089                                update_entry(ren1->dst_entry, one, a, b);
2090                                setup_rename_conflict_info(RENAME_NORMAL,
2091                                                           ren1->pair,
2092                                                           NULL,
2093                                                           branch1,
2094                                                           NULL,
2095                                                           ren1->dst_entry,
2096                                                           NULL,
2097                                                           o,
2098                                                           NULL,
2099                                                           NULL);
2100                        }
2101                }
2102        }
2103cleanup_and_return:
2104        string_list_clear(&a_by_dst, 0);
2105        string_list_clear(&b_by_dst, 0);
2106
2107        return clean_merge;
2108}
2109
2110struct rename_info {
2111        struct string_list *head_renames;
2112        struct string_list *merge_renames;
2113};
2114
2115static void initial_cleanup_rename(struct diff_queue_struct *pairs,
2116                                   struct hashmap *dir_renames)
2117{
2118        struct hashmap_iter iter;
2119        struct dir_rename_entry *e;
2120
2121        hashmap_iter_init(dir_renames, &iter);
2122        while ((e = hashmap_iter_next(&iter))) {
2123                free(e->dir);
2124                strbuf_release(&e->new_dir);
2125                /* possible_new_dirs already cleared in get_directory_renames */
2126        }
2127        hashmap_free(dir_renames, 1);
2128        free(dir_renames);
2129
2130        free(pairs->queue);
2131        free(pairs);
2132}
2133
2134static int handle_renames(struct merge_options *o,
2135                          struct tree *common,
2136                          struct tree *head,
2137                          struct tree *merge,
2138                          struct string_list *entries,
2139                          struct rename_info *ri)
2140{
2141        struct diff_queue_struct *head_pairs, *merge_pairs;
2142        struct hashmap *dir_re_head, *dir_re_merge;
2143        int clean;
2144
2145        ri->head_renames = NULL;
2146        ri->merge_renames = NULL;
2147
2148        if (!o->detect_rename)
2149                return 1;
2150
2151        head_pairs = get_diffpairs(o, common, head);
2152        merge_pairs = get_diffpairs(o, common, merge);
2153
2154        dir_re_head = get_directory_renames(head_pairs, head);
2155        dir_re_merge = get_directory_renames(merge_pairs, merge);
2156
2157        handle_directory_level_conflicts(o,
2158                                         dir_re_head, head,
2159                                         dir_re_merge, merge);
2160
2161        ri->head_renames  = get_renames(o, head_pairs,
2162                                        dir_re_merge, head,
2163                                        common, head, merge, entries);
2164        ri->merge_renames = get_renames(o, merge_pairs,
2165                                        dir_re_head, merge,
2166                                         common, head, merge, entries);
2167        clean = process_renames(o, ri->head_renames, ri->merge_renames);
2168
2169        /*
2170         * Some cleanup is deferred until cleanup_renames() because the
2171         * data structures are still needed and referenced in
2172         * process_entry().  But there are a few things we can free now.
2173         */
2174        initial_cleanup_rename(head_pairs, dir_re_head);
2175        initial_cleanup_rename(merge_pairs, dir_re_merge);
2176
2177        return clean;
2178}
2179
2180static void final_cleanup_rename(struct string_list *rename)
2181{
2182        const struct rename *re;
2183        int i;
2184
2185        if (rename == NULL)
2186                return;
2187
2188        for (i = 0; i < rename->nr; i++) {
2189                re = rename->items[i].util;
2190                diff_free_filepair(re->pair);
2191        }
2192        string_list_clear(rename, 1);
2193        free(rename);
2194}
2195
2196static void final_cleanup_renames(struct rename_info *re_info)
2197{
2198        final_cleanup_rename(re_info->head_renames);
2199        final_cleanup_rename(re_info->merge_renames);
2200}
2201
2202static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
2203{
2204        return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
2205}
2206
2207static int read_oid_strbuf(struct merge_options *o,
2208        const struct object_id *oid, struct strbuf *dst)
2209{
2210        void *buf;
2211        enum object_type type;
2212        unsigned long size;
2213        buf = read_sha1_file(oid->hash, &type, &size);
2214        if (!buf)
2215                return err(o, _("cannot read object %s"), oid_to_hex(oid));
2216        if (type != OBJ_BLOB) {
2217                free(buf);
2218                return err(o, _("object %s is not a blob"), oid_to_hex(oid));
2219        }
2220        strbuf_attach(dst, buf, size, size + 1);
2221        return 0;
2222}
2223
2224static int blob_unchanged(struct merge_options *opt,
2225                          const struct object_id *o_oid,
2226                          unsigned o_mode,
2227                          const struct object_id *a_oid,
2228                          unsigned a_mode,
2229                          int renormalize, const char *path)
2230{
2231        struct strbuf o = STRBUF_INIT;
2232        struct strbuf a = STRBUF_INIT;
2233        int ret = 0; /* assume changed for safety */
2234
2235        if (a_mode != o_mode)
2236                return 0;
2237        if (oid_eq(o_oid, a_oid))
2238                return 1;
2239        if (!renormalize)
2240                return 0;
2241
2242        assert(o_oid && a_oid);
2243        if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
2244                goto error_return;
2245        /*
2246         * Note: binary | is used so that both renormalizations are
2247         * performed.  Comparison can be skipped if both files are
2248         * unchanged since their sha1s have already been compared.
2249         */
2250        if (renormalize_buffer(&the_index, path, o.buf, o.len, &o) |
2251            renormalize_buffer(&the_index, path, a.buf, a.len, &a))
2252                ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
2253
2254error_return:
2255        strbuf_release(&o);
2256        strbuf_release(&a);
2257        return ret;
2258}
2259
2260static int handle_modify_delete(struct merge_options *o,
2261                                 const char *path,
2262                                 struct object_id *o_oid, int o_mode,
2263                                 struct object_id *a_oid, int a_mode,
2264                                 struct object_id *b_oid, int b_mode)
2265{
2266        const char *modify_branch, *delete_branch;
2267        struct object_id *changed_oid;
2268        int changed_mode;
2269
2270        if (a_oid) {
2271                modify_branch = o->branch1;
2272                delete_branch = o->branch2;
2273                changed_oid = a_oid;
2274                changed_mode = a_mode;
2275        } else {
2276                modify_branch = o->branch2;
2277                delete_branch = o->branch1;
2278                changed_oid = b_oid;
2279                changed_mode = b_mode;
2280        }
2281
2282        return handle_change_delete(o,
2283                                    path, NULL,
2284                                    o_oid, o_mode,
2285                                    changed_oid, changed_mode,
2286                                    modify_branch, delete_branch,
2287                                    _("modify"), _("modified"));
2288}
2289
2290static int merge_content(struct merge_options *o,
2291                         const char *path,
2292                         struct object_id *o_oid, int o_mode,
2293                         struct object_id *a_oid, int a_mode,
2294                         struct object_id *b_oid, int b_mode,
2295                         struct rename_conflict_info *rename_conflict_info)
2296{
2297        const char *reason = _("content");
2298        const char *path1 = NULL, *path2 = NULL;
2299        struct merge_file_info mfi;
2300        struct diff_filespec one, a, b;
2301        unsigned df_conflict_remains = 0;
2302
2303        if (!o_oid) {
2304                reason = _("add/add");
2305                o_oid = (struct object_id *)&null_oid;
2306        }
2307        one.path = a.path = b.path = (char *)path;
2308        oidcpy(&one.oid, o_oid);
2309        one.mode = o_mode;
2310        oidcpy(&a.oid, a_oid);
2311        a.mode = a_mode;
2312        oidcpy(&b.oid, b_oid);
2313        b.mode = b_mode;
2314
2315        if (rename_conflict_info) {
2316                struct diff_filepair *pair1 = rename_conflict_info->pair1;
2317
2318                path1 = (o->branch1 == rename_conflict_info->branch1) ?
2319                        pair1->two->path : pair1->one->path;
2320                /* If rename_conflict_info->pair2 != NULL, we are in
2321                 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
2322                 * normal rename.
2323                 */
2324                path2 = (rename_conflict_info->pair2 ||
2325                         o->branch2 == rename_conflict_info->branch1) ?
2326                        pair1->two->path : pair1->one->path;
2327
2328                if (dir_in_way(path, !o->call_depth,
2329                               S_ISGITLINK(pair1->two->mode)))
2330                        df_conflict_remains = 1;
2331        }
2332        if (merge_file_special_markers(o, &one, &a, &b,
2333                                       o->branch1, path1,
2334                                       o->branch2, path2, &mfi))
2335                return -1;
2336
2337        if (mfi.clean && !df_conflict_remains &&
2338            oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
2339                int path_renamed_outside_HEAD;
2340                output(o, 3, _("Skipped %s (merged same as existing)"), path);
2341                /*
2342                 * The content merge resulted in the same file contents we
2343                 * already had.  We can return early if those file contents
2344                 * are recorded at the correct path (which may not be true
2345                 * if the merge involves a rename).
2346                 */
2347                path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
2348                if (!path_renamed_outside_HEAD) {
2349                        add_cacheinfo(o, mfi.mode, &mfi.oid, path,
2350                                      0, (!o->call_depth), 0);
2351                        return mfi.clean;
2352                }
2353        } else
2354                output(o, 2, _("Auto-merging %s"), path);
2355
2356        if (!mfi.clean) {
2357                if (S_ISGITLINK(mfi.mode))
2358                        reason = _("submodule");
2359                output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
2360                                reason, path);
2361                if (rename_conflict_info && !df_conflict_remains)
2362                        if (update_stages(o, path, &one, &a, &b))
2363                                return -1;
2364        }
2365
2366        if (df_conflict_remains) {
2367                char *new_path;
2368                if (o->call_depth) {
2369                        remove_file_from_cache(path);
2370                } else {
2371                        if (!mfi.clean) {
2372                                if (update_stages(o, path, &one, &a, &b))
2373                                        return -1;
2374                        } else {
2375                                int file_from_stage2 = was_tracked(path);
2376                                struct diff_filespec merged;
2377                                oidcpy(&merged.oid, &mfi.oid);
2378                                merged.mode = mfi.mode;
2379
2380                                if (update_stages(o, path, NULL,
2381                                                  file_from_stage2 ? &merged : NULL,
2382                                                  file_from_stage2 ? NULL : &merged))
2383                                        return -1;
2384                        }
2385
2386                }
2387                new_path = unique_path(o, path, rename_conflict_info->branch1);
2388                output(o, 1, _("Adding as %s instead"), new_path);
2389                if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
2390                        free(new_path);
2391                        return -1;
2392                }
2393                free(new_path);
2394                mfi.clean = 0;
2395        } else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
2396                return -1;
2397        return mfi.clean;
2398}
2399
2400/* Per entry merge function */
2401static int process_entry(struct merge_options *o,
2402                         const char *path, struct stage_data *entry)
2403{
2404        int clean_merge = 1;
2405        int normalize = o->renormalize;
2406        unsigned o_mode = entry->stages[1].mode;
2407        unsigned a_mode = entry->stages[2].mode;
2408        unsigned b_mode = entry->stages[3].mode;
2409        struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
2410        struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
2411        struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
2412
2413        entry->processed = 1;
2414        if (entry->rename_conflict_info) {
2415                struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
2416                switch (conflict_info->rename_type) {
2417                case RENAME_NORMAL:
2418                case RENAME_ONE_FILE_TO_ONE:
2419                        clean_merge = merge_content(o, path,
2420                                                    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
2421                                                    conflict_info);
2422                        break;
2423                case RENAME_DELETE:
2424                        clean_merge = 0;
2425                        if (conflict_rename_delete(o,
2426                                                   conflict_info->pair1,
2427                                                   conflict_info->branch1,
2428                                                   conflict_info->branch2))
2429                                clean_merge = -1;
2430                        break;
2431                case RENAME_ONE_FILE_TO_TWO:
2432                        clean_merge = 0;
2433                        if (conflict_rename_rename_1to2(o, conflict_info))
2434                                clean_merge = -1;
2435                        break;
2436                case RENAME_TWO_FILES_TO_ONE:
2437                        clean_merge = 0;
2438                        if (conflict_rename_rename_2to1(o, conflict_info))
2439                                clean_merge = -1;
2440                        break;
2441                default:
2442                        entry->processed = 0;
2443                        break;
2444                }
2445        } else if (o_oid && (!a_oid || !b_oid)) {
2446                /* Case A: Deleted in one */
2447                if ((!a_oid && !b_oid) ||
2448                    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
2449                    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
2450                        /* Deleted in both or deleted in one and
2451                         * unchanged in the other */
2452                        if (a_oid)
2453                                output(o, 2, _("Removing %s"), path);
2454                        /* do not touch working file if it did not exist */
2455                        remove_file(o, 1, path, !a_oid);
2456                } else {
2457                        /* Modify/delete; deleted side may have put a directory in the way */
2458                        clean_merge = 0;
2459                        if (handle_modify_delete(o, path, o_oid, o_mode,
2460                                                 a_oid, a_mode, b_oid, b_mode))
2461                                clean_merge = -1;
2462                }
2463        } else if ((!o_oid && a_oid && !b_oid) ||
2464                   (!o_oid && !a_oid && b_oid)) {
2465                /* Case B: Added in one. */
2466                /* [nothing|directory] -> ([nothing|directory], file) */
2467
2468                const char *add_branch;
2469                const char *other_branch;
2470                unsigned mode;
2471                const struct object_id *oid;
2472                const char *conf;
2473
2474                if (a_oid) {
2475                        add_branch = o->branch1;
2476                        other_branch = o->branch2;
2477                        mode = a_mode;
2478                        oid = a_oid;
2479                        conf = _("file/directory");
2480                } else {
2481                        add_branch = o->branch2;
2482                        other_branch = o->branch1;
2483                        mode = b_mode;
2484                        oid = b_oid;
2485                        conf = _("directory/file");
2486                }
2487                if (dir_in_way(path,
2488                               !o->call_depth && !S_ISGITLINK(a_mode),
2489                               0)) {
2490                        char *new_path = unique_path(o, path, add_branch);
2491                        clean_merge = 0;
2492                        output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
2493                               "Adding %s as %s"),
2494                               conf, path, other_branch, path, new_path);
2495                        if (update_file(o, 0, oid, mode, new_path))
2496                                clean_merge = -1;
2497                        else if (o->call_depth)
2498                                remove_file_from_cache(path);
2499                        free(new_path);
2500                } else {
2501                        output(o, 2, _("Adding %s"), path);
2502                        /* do not overwrite file if already present */
2503                        if (update_file_flags(o, oid, mode, path, 1, !a_oid))
2504                                clean_merge = -1;
2505                }
2506        } else if (a_oid && b_oid) {
2507                /* Case C: Added in both (check for same permissions) and */
2508                /* case D: Modified in both, but differently. */
2509                clean_merge = merge_content(o, path,
2510                                            o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
2511                                            NULL);
2512        } else if (!o_oid && !a_oid && !b_oid) {
2513                /*
2514                 * this entry was deleted altogether. a_mode == 0 means
2515                 * we had that path and want to actively remove it.
2516                 */
2517                remove_file(o, 1, path, !a_mode);
2518        } else
2519                die("BUG: fatal merge failure, shouldn't happen.");
2520
2521        return clean_merge;
2522}
2523
2524int merge_trees(struct merge_options *o,
2525                struct tree *head,
2526                struct tree *merge,
2527                struct tree *common,
2528                struct tree **result)
2529{
2530        int code, clean;
2531
2532        if (o->subtree_shift) {
2533                merge = shift_tree_object(head, merge, o->subtree_shift);
2534                common = shift_tree_object(head, common, o->subtree_shift);
2535        }
2536
2537        if (oid_eq(&common->object.oid, &merge->object.oid)) {
2538                struct strbuf sb = STRBUF_INIT;
2539
2540                if (!o->call_depth && index_has_changes(&sb)) {
2541                        err(o, _("Dirty index: cannot merge (dirty: %s)"),
2542                            sb.buf);
2543                        return 0;
2544                }
2545                output(o, 0, _("Already up to date!"));
2546                *result = head;
2547                return 1;
2548        }
2549
2550        code = git_merge_trees(o->call_depth, common, head, merge);
2551
2552        if (code != 0) {
2553                if (show(o, 4) || o->call_depth)
2554                        err(o, _("merging of trees %s and %s failed"),
2555                            oid_to_hex(&head->object.oid),
2556                            oid_to_hex(&merge->object.oid));
2557                return -1;
2558        }
2559
2560        if (unmerged_cache()) {
2561                struct string_list *entries;
2562                struct rename_info re_info;
2563                int i;
2564                /*
2565                 * Only need the hashmap while processing entries, so
2566                 * initialize it here and free it when we are done running
2567                 * through the entries. Keeping it in the merge_options as
2568                 * opposed to decaring a local hashmap is for convenience
2569                 * so that we don't have to pass it to around.
2570                 */
2571                hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
2572                get_files_dirs(o, head);
2573                get_files_dirs(o, merge);
2574
2575                entries = get_unmerged();
2576                clean = handle_renames(o, common, head, merge, entries,
2577                                       &re_info);
2578                record_df_conflict_files(o, entries);
2579                if (clean < 0)
2580                        goto cleanup;
2581                for (i = entries->nr-1; 0 <= i; i--) {
2582                        const char *path = entries->items[i].string;
2583                        struct stage_data *e = entries->items[i].util;
2584                        if (!e->processed) {
2585                                int ret = process_entry(o, path, e);
2586                                if (!ret)
2587                                        clean = 0;
2588                                else if (ret < 0) {
2589                                        clean = ret;
2590                                        goto cleanup;
2591                                }
2592                        }
2593                }
2594                for (i = 0; i < entries->nr; i++) {
2595                        struct stage_data *e = entries->items[i].util;
2596                        if (!e->processed)
2597                                die("BUG: unprocessed path??? %s",
2598                                    entries->items[i].string);
2599                }
2600
2601cleanup:
2602                final_cleanup_renames(&re_info);
2603
2604                string_list_clear(entries, 1);
2605                free(entries);
2606
2607                hashmap_free(&o->current_file_dir_set, 1);
2608
2609                if (clean < 0)
2610                        return clean;
2611        }
2612        else
2613                clean = 1;
2614
2615        if (o->call_depth && !(*result = write_tree_from_memory(o)))
2616                return -1;
2617
2618        return clean;
2619}
2620
2621static struct commit_list *reverse_commit_list(struct commit_list *list)
2622{
2623        struct commit_list *next = NULL, *current, *backup;
2624        for (current = list; current; current = backup) {
2625                backup = current->next;
2626                current->next = next;
2627                next = current;
2628        }
2629        return next;
2630}
2631
2632/*
2633 * Merge the commits h1 and h2, return the resulting virtual
2634 * commit object and a flag indicating the cleanness of the merge.
2635 */
2636int merge_recursive(struct merge_options *o,
2637                    struct commit *h1,
2638                    struct commit *h2,
2639                    struct commit_list *ca,
2640                    struct commit **result)
2641{
2642        struct commit_list *iter;
2643        struct commit *merged_common_ancestors;
2644        struct tree *mrtree = mrtree;
2645        int clean;
2646
2647        if (show(o, 4)) {
2648                output(o, 4, _("Merging:"));
2649                output_commit_title(o, h1);
2650                output_commit_title(o, h2);
2651        }
2652
2653        if (!ca) {
2654                ca = get_merge_bases(h1, h2);
2655                ca = reverse_commit_list(ca);
2656        }
2657
2658        if (show(o, 5)) {
2659                unsigned cnt = commit_list_count(ca);
2660
2661                output(o, 5, Q_("found %u common ancestor:",
2662                                "found %u common ancestors:", cnt), cnt);
2663                for (iter = ca; iter; iter = iter->next)
2664                        output_commit_title(o, iter->item);
2665        }
2666
2667        merged_common_ancestors = pop_commit(&ca);
2668        if (merged_common_ancestors == NULL) {
2669                /* if there is no common ancestor, use an empty tree */
2670                struct tree *tree;
2671
2672                tree = lookup_tree(the_hash_algo->empty_tree);
2673                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
2674        }
2675
2676        for (iter = ca; iter; iter = iter->next) {
2677                const char *saved_b1, *saved_b2;
2678                o->call_depth++;
2679                /*
2680                 * When the merge fails, the result contains files
2681                 * with conflict markers. The cleanness flag is
2682                 * ignored (unless indicating an error), it was never
2683                 * actually used, as result of merge_trees has always
2684                 * overwritten it: the committed "conflicts" were
2685                 * already resolved.
2686                 */
2687                discard_cache();
2688                saved_b1 = o->branch1;
2689                saved_b2 = o->branch2;
2690                o->branch1 = "Temporary merge branch 1";
2691                o->branch2 = "Temporary merge branch 2";
2692                if (merge_recursive(o, merged_common_ancestors, iter->item,
2693                                    NULL, &merged_common_ancestors) < 0)
2694                        return -1;
2695                o->branch1 = saved_b1;
2696                o->branch2 = saved_b2;
2697                o->call_depth--;
2698
2699                if (!merged_common_ancestors)
2700                        return err(o, _("merge returned no commit"));
2701        }
2702
2703        discard_cache();
2704        if (!o->call_depth)
2705                read_cache();
2706
2707        o->ancestor = "merged common ancestors";
2708        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
2709                            &mrtree);
2710        if (clean < 0) {
2711                flush_output(o);
2712                return clean;
2713        }
2714
2715        if (o->call_depth) {
2716                *result = make_virtual_commit(mrtree, "merged tree");
2717                commit_list_insert(h1, &(*result)->parents);
2718                commit_list_insert(h2, &(*result)->parents->next);
2719        }
2720        flush_output(o);
2721        if (!o->call_depth && o->buffer_output < 2)
2722                strbuf_release(&o->obuf);
2723        if (show(o, 2))
2724                diff_warn_rename_limit("merge.renamelimit",
2725                                       o->needed_rename_limit, 0);
2726        return clean;
2727}
2728
2729static struct commit *get_ref(const struct object_id *oid, const char *name)
2730{
2731        struct object *object;
2732
2733        object = deref_tag(parse_object(oid), name, strlen(name));
2734        if (!object)
2735                return NULL;
2736        if (object->type == OBJ_TREE)
2737                return make_virtual_commit((struct tree*)object, name);
2738        if (object->type != OBJ_COMMIT)
2739                return NULL;
2740        if (parse_commit((struct commit *)object))
2741                return NULL;
2742        return (struct commit *)object;
2743}
2744
2745int merge_recursive_generic(struct merge_options *o,
2746                            const struct object_id *head,
2747                            const struct object_id *merge,
2748                            int num_base_list,
2749                            const struct object_id **base_list,
2750                            struct commit **result)
2751{
2752        int clean;
2753        struct lock_file lock = LOCK_INIT;
2754        struct commit *head_commit = get_ref(head, o->branch1);
2755        struct commit *next_commit = get_ref(merge, o->branch2);
2756        struct commit_list *ca = NULL;
2757
2758        if (base_list) {
2759                int i;
2760                for (i = 0; i < num_base_list; ++i) {
2761                        struct commit *base;
2762                        if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
2763                                return err(o, _("Could not parse object '%s'"),
2764                                        oid_to_hex(base_list[i]));
2765                        commit_list_insert(base, &ca);
2766                }
2767        }
2768
2769        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
2770        clean = merge_recursive(o, head_commit, next_commit, ca,
2771                        result);
2772        if (clean < 0)
2773                return clean;
2774
2775        if (active_cache_changed &&
2776            write_locked_index(&the_index, &lock, COMMIT_LOCK))
2777                return err(o, _("Unable to write index."));
2778
2779        return clean ? 0 : 1;
2780}
2781
2782static void merge_recursive_config(struct merge_options *o)
2783{
2784        git_config_get_int("merge.verbosity", &o->verbosity);
2785        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2786        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2787        git_config(git_xmerge_config, NULL);
2788}
2789
2790void init_merge_options(struct merge_options *o)
2791{
2792        const char *merge_verbosity;
2793        memset(o, 0, sizeof(struct merge_options));
2794        o->verbosity = 2;
2795        o->buffer_output = 1;
2796        o->diff_rename_limit = -1;
2797        o->merge_rename_limit = -1;
2798        o->renormalize = 0;
2799        o->detect_rename = 1;
2800        merge_recursive_config(o);
2801        merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
2802        if (merge_verbosity)
2803                o->verbosity = strtol(merge_verbosity, NULL, 10);
2804        if (o->verbosity >= 5)
2805                o->buffer_output = 0;
2806        strbuf_init(&o->obuf, 0);
2807        string_list_init(&o->df_conflict_file_set, 1);
2808}
2809
2810int parse_merge_opt(struct merge_options *o, const char *s)
2811{
2812        const char *arg;
2813
2814        if (!s || !*s)
2815                return -1;
2816        if (!strcmp(s, "ours"))
2817                o->recursive_variant = MERGE_RECURSIVE_OURS;
2818        else if (!strcmp(s, "theirs"))
2819                o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2820        else if (!strcmp(s, "subtree"))
2821                o->subtree_shift = "";
2822        else if (skip_prefix(s, "subtree=", &arg))
2823                o->subtree_shift = arg;
2824        else if (!strcmp(s, "patience"))
2825                o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2826        else if (!strcmp(s, "histogram"))
2827                o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2828        else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2829                long value = parse_algorithm_value(arg);
2830                if (value < 0)
2831                        return -1;
2832                /* clear out previous settings */
2833                DIFF_XDL_CLR(o, NEED_MINIMAL);
2834                o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2835                o->xdl_opts |= value;
2836        }
2837        else if (!strcmp(s, "ignore-space-change"))
2838                DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
2839        else if (!strcmp(s, "ignore-all-space"))
2840                DIFF_XDL_SET(o, IGNORE_WHITESPACE);
2841        else if (!strcmp(s, "ignore-space-at-eol"))
2842                DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
2843        else if (!strcmp(s, "ignore-cr-at-eol"))
2844                DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
2845        else if (!strcmp(s, "renormalize"))
2846                o->renormalize = 1;
2847        else if (!strcmp(s, "no-renormalize"))
2848                o->renormalize = 0;
2849        else if (!strcmp(s, "no-renames"))
2850                o->detect_rename = 0;
2851        else if (!strcmp(s, "find-renames")) {
2852                o->detect_rename = 1;
2853                o->rename_score = 0;
2854        }
2855        else if (skip_prefix(s, "find-renames=", &arg) ||
2856                 skip_prefix(s, "rename-threshold=", &arg)) {
2857                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2858                        return -1;
2859                o->detect_rename = 1;
2860        }
2861        else
2862                return -1;
2863        return 0;
2864}