0bd3f37c37bba6d7f40346372122131a4405e577
   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_DIR,
 184        RENAME_DELETE,
 185        RENAME_ONE_FILE_TO_ONE,
 186        RENAME_ONE_FILE_TO_TWO,
 187        RENAME_TWO_FILES_TO_ONE
 188};
 189
 190struct rename_conflict_info {
 191        enum rename_type rename_type;
 192        struct diff_filepair *pair1;
 193        struct diff_filepair *pair2;
 194        const char *branch1;
 195        const char *branch2;
 196        struct stage_data *dst_entry1;
 197        struct stage_data *dst_entry2;
 198        struct diff_filespec ren1_other;
 199        struct diff_filespec ren2_other;
 200};
 201
 202/*
 203 * Since we want to write the index eventually, we cannot reuse the index
 204 * for these (temporary) data.
 205 */
 206struct stage_data {
 207        struct {
 208                unsigned mode;
 209                struct object_id oid;
 210        } stages[4];
 211        struct rename_conflict_info *rename_conflict_info;
 212        unsigned processed:1;
 213};
 214
 215static inline void setup_rename_conflict_info(enum rename_type rename_type,
 216                                              struct diff_filepair *pair1,
 217                                              struct diff_filepair *pair2,
 218                                              const char *branch1,
 219                                              const char *branch2,
 220                                              struct stage_data *dst_entry1,
 221                                              struct stage_data *dst_entry2,
 222                                              struct merge_options *o,
 223                                              struct stage_data *src_entry1,
 224                                              struct stage_data *src_entry2)
 225{
 226        struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
 227        ci->rename_type = rename_type;
 228        ci->pair1 = pair1;
 229        ci->branch1 = branch1;
 230        ci->branch2 = branch2;
 231
 232        ci->dst_entry1 = dst_entry1;
 233        dst_entry1->rename_conflict_info = ci;
 234        dst_entry1->processed = 0;
 235
 236        assert(!pair2 == !dst_entry2);
 237        if (dst_entry2) {
 238                ci->dst_entry2 = dst_entry2;
 239                ci->pair2 = pair2;
 240                dst_entry2->rename_conflict_info = ci;
 241        }
 242
 243        if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 244                /*
 245                 * For each rename, there could have been
 246                 * modifications on the side of history where that
 247                 * file was not renamed.
 248                 */
 249                int ostage1 = o->branch1 == branch1 ? 3 : 2;
 250                int ostage2 = ostage1 ^ 1;
 251
 252                ci->ren1_other.path = pair1->one->path;
 253                oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 254                ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 255
 256                ci->ren2_other.path = pair2->one->path;
 257                oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 258                ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 259        }
 260}
 261
 262static int show(struct merge_options *o, int v)
 263{
 264        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 265}
 266
 267__attribute__((format (printf, 3, 4)))
 268static void output(struct merge_options *o, int v, const char *fmt, ...)
 269{
 270        va_list ap;
 271
 272        if (!show(o, v))
 273                return;
 274
 275        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 276
 277        va_start(ap, fmt);
 278        strbuf_vaddf(&o->obuf, fmt, ap);
 279        va_end(ap);
 280
 281        strbuf_addch(&o->obuf, '\n');
 282        if (!o->buffer_output)
 283                flush_output(o);
 284}
 285
 286static void output_commit_title(struct merge_options *o, struct commit *commit)
 287{
 288        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 289        if (commit->util)
 290                strbuf_addf(&o->obuf, "virtual %s\n",
 291                        merge_remote_util(commit)->name);
 292        else {
 293                strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
 294                                         DEFAULT_ABBREV);
 295                strbuf_addch(&o->obuf, ' ');
 296                if (parse_commit(commit) != 0)
 297                        strbuf_addstr(&o->obuf, _("(bad commit)\n"));
 298                else {
 299                        const char *title;
 300                        const char *msg = get_commit_buffer(commit, NULL);
 301                        int len = find_commit_subject(msg, &title);
 302                        if (len)
 303                                strbuf_addf(&o->obuf, "%.*s\n", len, title);
 304                        unuse_commit_buffer(commit, msg);
 305                }
 306        }
 307        flush_output(o);
 308}
 309
 310static int add_cacheinfo(struct merge_options *o,
 311                unsigned int mode, const struct object_id *oid,
 312                const char *path, int stage, int refresh, int options)
 313{
 314        struct cache_entry *ce;
 315        int ret;
 316
 317        ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
 318        if (!ce)
 319                return err(o, _("addinfo_cache failed for path '%s'"), path);
 320
 321        ret = add_cache_entry(ce, options);
 322        if (refresh) {
 323                struct cache_entry *nce;
 324
 325                nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 326                if (!nce)
 327                        return err(o, _("addinfo_cache failed for path '%s'"), path);
 328                if (nce != ce)
 329                        ret = add_cache_entry(nce, options);
 330        }
 331        return ret;
 332}
 333
 334static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 335{
 336        parse_tree(tree);
 337        init_tree_desc(desc, tree->buffer, tree->size);
 338}
 339
 340static int git_merge_trees(struct merge_options *o,
 341                           struct tree *common,
 342                           struct tree *head,
 343                           struct tree *merge)
 344{
 345        int rc;
 346        struct tree_desc t[3];
 347
 348        memset(&o->unpack_opts, 0, sizeof(o->unpack_opts));
 349        if (o->call_depth)
 350                o->unpack_opts.index_only = 1;
 351        else
 352                o->unpack_opts.update = 1;
 353        o->unpack_opts.merge = 1;
 354        o->unpack_opts.head_idx = 2;
 355        o->unpack_opts.fn = threeway_merge;
 356        o->unpack_opts.src_index = &the_index;
 357        o->unpack_opts.dst_index = &the_index;
 358        setup_unpack_trees_porcelain(&o->unpack_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, &o->unpack_opts);
 365        /*
 366         * unpack_trees NULLifies src_index, but it's used in verify_uptodate,
 367         * so set to the new index which will usually have modification
 368         * timestamp info copied over.
 369         */
 370        o->unpack_opts.src_index = &the_index;
 371        cache_tree_free(&active_cache_tree);
 372        return rc;
 373}
 374
 375struct tree *write_tree_from_memory(struct merge_options *o)
 376{
 377        struct tree *result = NULL;
 378
 379        if (unmerged_cache()) {
 380                int i;
 381                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 382                for (i = 0; i < active_nr; i++) {
 383                        const struct cache_entry *ce = active_cache[i];
 384                        if (ce_stage(ce))
 385                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 386                                        (int)ce_namelen(ce), ce->name);
 387                }
 388                die("BUG: unmerged index entries in merge-recursive.c");
 389        }
 390
 391        if (!active_cache_tree)
 392                active_cache_tree = cache_tree();
 393
 394        if (!cache_tree_fully_valid(active_cache_tree) &&
 395            cache_tree_update(&the_index, 0) < 0) {
 396                err(o, _("error building trees"));
 397                return NULL;
 398        }
 399
 400        result = lookup_tree(&active_cache_tree->oid);
 401
 402        return result;
 403}
 404
 405static int save_files_dirs(const unsigned char *sha1,
 406                struct strbuf *base, const char *path,
 407                unsigned int mode, int stage, void *context)
 408{
 409        struct path_hashmap_entry *entry;
 410        int baselen = base->len;
 411        struct merge_options *o = context;
 412
 413        strbuf_addstr(base, path);
 414
 415        FLEX_ALLOC_MEM(entry, path, base->buf, base->len);
 416        hashmap_entry_init(entry, path_hash(entry->path));
 417        hashmap_add(&o->current_file_dir_set, entry);
 418
 419        strbuf_setlen(base, baselen);
 420        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 421}
 422
 423static void get_files_dirs(struct merge_options *o, struct tree *tree)
 424{
 425        struct pathspec match_all;
 426        memset(&match_all, 0, sizeof(match_all));
 427        read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o);
 428}
 429
 430static int get_tree_entry_if_blob(const unsigned char *tree,
 431                                  const char *path,
 432                                  unsigned char *hashy,
 433                                  unsigned int *mode_o)
 434{
 435        int ret;
 436
 437        ret = get_tree_entry(tree, path, hashy, mode_o);
 438        if (S_ISDIR(*mode_o)) {
 439                hashcpy(hashy, null_sha1);
 440                *mode_o = 0;
 441        }
 442        return ret;
 443}
 444
 445/*
 446 * Returns an index_entry instance which doesn't have to correspond to
 447 * a real cache entry in Git's index.
 448 */
 449static struct stage_data *insert_stage_data(const char *path,
 450                struct tree *o, struct tree *a, struct tree *b,
 451                struct string_list *entries)
 452{
 453        struct string_list_item *item;
 454        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 455        get_tree_entry_if_blob(o->object.oid.hash, path,
 456                               e->stages[1].oid.hash, &e->stages[1].mode);
 457        get_tree_entry_if_blob(a->object.oid.hash, path,
 458                               e->stages[2].oid.hash, &e->stages[2].mode);
 459        get_tree_entry_if_blob(b->object.oid.hash, path,
 460                               e->stages[3].oid.hash, &e->stages[3].mode);
 461        item = string_list_insert(entries, path);
 462        item->util = e;
 463        return e;
 464}
 465
 466/*
 467 * Create a dictionary mapping file names to stage_data objects. The
 468 * dictionary contains one entry for every path with a non-zero stage entry.
 469 */
 470static struct string_list *get_unmerged(void)
 471{
 472        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 473        int i;
 474
 475        unmerged->strdup_strings = 1;
 476
 477        for (i = 0; i < active_nr; i++) {
 478                struct string_list_item *item;
 479                struct stage_data *e;
 480                const struct cache_entry *ce = active_cache[i];
 481                if (!ce_stage(ce))
 482                        continue;
 483
 484                item = string_list_lookup(unmerged, ce->name);
 485                if (!item) {
 486                        item = string_list_insert(unmerged, ce->name);
 487                        item->util = xcalloc(1, sizeof(struct stage_data));
 488                }
 489                e = item->util;
 490                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 491                oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
 492        }
 493
 494        return unmerged;
 495}
 496
 497static int string_list_df_name_compare(const char *one, const char *two)
 498{
 499        int onelen = strlen(one);
 500        int twolen = strlen(two);
 501        /*
 502         * Here we only care that entries for D/F conflicts are
 503         * adjacent, in particular with the file of the D/F conflict
 504         * appearing before files below the corresponding directory.
 505         * The order of the rest of the list is irrelevant for us.
 506         *
 507         * To achieve this, we sort with df_name_compare and provide
 508         * the mode S_IFDIR so that D/F conflicts will sort correctly.
 509         * We use the mode S_IFDIR for everything else for simplicity,
 510         * since in other cases any changes in their order due to
 511         * sorting cause no problems for us.
 512         */
 513        int cmp = df_name_compare(one, onelen, S_IFDIR,
 514                                  two, twolen, S_IFDIR);
 515        /*
 516         * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 517         * that 'foo' comes before 'foo/bar'.
 518         */
 519        if (cmp)
 520                return cmp;
 521        return onelen - twolen;
 522}
 523
 524static void record_df_conflict_files(struct merge_options *o,
 525                                     struct string_list *entries)
 526{
 527        /* If there is a D/F conflict and the file for such a conflict
 528         * currently exist in the working tree, we want to allow it to be
 529         * removed to make room for the corresponding directory if needed.
 530         * The files underneath the directories of such D/F conflicts will
 531         * be processed before the corresponding file involved in the D/F
 532         * conflict.  If the D/F directory ends up being removed by the
 533         * merge, then we won't have to touch the D/F file.  If the D/F
 534         * directory needs to be written to the working copy, then the D/F
 535         * file will simply be removed (in make_room_for_path()) to make
 536         * room for the necessary paths.  Note that if both the directory
 537         * and the file need to be present, then the D/F file will be
 538         * reinstated with a new unique name at the time it is processed.
 539         */
 540        struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
 541        const char *last_file = NULL;
 542        int last_len = 0;
 543        int i;
 544
 545        /*
 546         * If we're merging merge-bases, we don't want to bother with
 547         * any working directory changes.
 548         */
 549        if (o->call_depth)
 550                return;
 551
 552        /* Ensure D/F conflicts are adjacent in the entries list. */
 553        for (i = 0; i < entries->nr; i++) {
 554                struct string_list_item *next = &entries->items[i];
 555                string_list_append(&df_sorted_entries, next->string)->util =
 556                                   next->util;
 557        }
 558        df_sorted_entries.cmp = string_list_df_name_compare;
 559        string_list_sort(&df_sorted_entries);
 560
 561        string_list_clear(&o->df_conflict_file_set, 1);
 562        for (i = 0; i < df_sorted_entries.nr; i++) {
 563                const char *path = df_sorted_entries.items[i].string;
 564                int len = strlen(path);
 565                struct stage_data *e = df_sorted_entries.items[i].util;
 566
 567                /*
 568                 * Check if last_file & path correspond to a D/F conflict;
 569                 * i.e. whether path is last_file+'/'+<something>.
 570                 * If so, record that it's okay to remove last_file to make
 571                 * room for path and friends if needed.
 572                 */
 573                if (last_file &&
 574                    len > last_len &&
 575                    memcmp(path, last_file, last_len) == 0 &&
 576                    path[last_len] == '/') {
 577                        string_list_insert(&o->df_conflict_file_set, last_file);
 578                }
 579
 580                /*
 581                 * Determine whether path could exist as a file in the
 582                 * working directory as a possible D/F conflict.  This
 583                 * will only occur when it exists in stage 2 as a
 584                 * file.
 585                 */
 586                if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 587                        last_file = path;
 588                        last_len = len;
 589                } else {
 590                        last_file = NULL;
 591                }
 592        }
 593        string_list_clear(&df_sorted_entries, 0);
 594}
 595
 596struct rename {
 597        struct diff_filepair *pair;
 598        /*
 599         * Purpose of src_entry and dst_entry:
 600         *
 601         * If 'before' is renamed to 'after' then src_entry will contain
 602         * the versions of 'before' from the merge_base, HEAD, and MERGE in
 603         * stages 1, 2, and 3; dst_entry will contain the respective
 604         * versions of 'after' in corresponding locations.  Thus, we have a
 605         * total of six modes and oids, though some will be null.  (Stage 0
 606         * is ignored; we're interested in handling conflicts.)
 607         *
 608         * Since we don't turn on break-rewrites by default, neither
 609         * src_entry nor dst_entry can have all three of their stages have
 610         * non-null oids, meaning at most four of the six will be non-null.
 611         * Also, since this is a rename, both src_entry and dst_entry will
 612         * have at least one non-null oid, meaning at least two will be
 613         * non-null.  Of the six oids, a typical rename will have three be
 614         * non-null.  Only two implies a rename/delete, and four implies a
 615         * rename/add.
 616         */
 617        struct stage_data *src_entry;
 618        struct stage_data *dst_entry;
 619        unsigned add_turned_into_rename:1;
 620        unsigned processed:1;
 621};
 622
 623static int update_stages(struct merge_options *opt, const char *path,
 624                         const struct diff_filespec *o,
 625                         const struct diff_filespec *a,
 626                         const struct diff_filespec *b)
 627{
 628
 629        /*
 630         * NOTE: It is usually a bad idea to call update_stages on a path
 631         * before calling update_file on that same path, since it can
 632         * sometimes lead to spurious "refusing to lose untracked file..."
 633         * messages from update_file (via make_room_for path via
 634         * would_lose_untracked).  Instead, reverse the order of the calls
 635         * (executing update_file first and then update_stages).
 636         */
 637        int clear = 1;
 638        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 639        if (clear)
 640                if (remove_file_from_cache(path))
 641                        return -1;
 642        if (o)
 643                if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
 644                        return -1;
 645        if (a)
 646                if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
 647                        return -1;
 648        if (b)
 649                if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
 650                        return -1;
 651        return 0;
 652}
 653
 654static int update_stages_for_stage_data(struct merge_options *opt,
 655                                        const char *path,
 656                                        const struct stage_data *stage_data)
 657{
 658        struct diff_filespec o, a, b;
 659
 660        o.mode = stage_data->stages[1].mode;
 661        oidcpy(&o.oid, &stage_data->stages[1].oid);
 662
 663        a.mode = stage_data->stages[2].mode;
 664        oidcpy(&a.oid, &stage_data->stages[2].oid);
 665
 666        b.mode = stage_data->stages[3].mode;
 667        oidcpy(&b.oid, &stage_data->stages[3].oid);
 668
 669        return update_stages(opt, path,
 670                             is_null_oid(&o.oid) ? NULL : &o,
 671                             is_null_oid(&a.oid) ? NULL : &a,
 672                             is_null_oid(&b.oid) ? NULL : &b);
 673}
 674
 675static void update_entry(struct stage_data *entry,
 676                         struct diff_filespec *o,
 677                         struct diff_filespec *a,
 678                         struct diff_filespec *b)
 679{
 680        entry->processed = 0;
 681        entry->stages[1].mode = o->mode;
 682        entry->stages[2].mode = a->mode;
 683        entry->stages[3].mode = b->mode;
 684        oidcpy(&entry->stages[1].oid, &o->oid);
 685        oidcpy(&entry->stages[2].oid, &a->oid);
 686        oidcpy(&entry->stages[3].oid, &b->oid);
 687}
 688
 689static int remove_file(struct merge_options *o, int clean,
 690                       const char *path, int no_wd)
 691{
 692        int update_cache = o->call_depth || clean;
 693        int update_working_directory = !o->call_depth && !no_wd;
 694
 695        if (update_cache) {
 696                if (remove_file_from_cache(path))
 697                        return -1;
 698        }
 699        if (update_working_directory) {
 700                if (ignore_case) {
 701                        struct cache_entry *ce;
 702                        ce = cache_file_exists(path, strlen(path), ignore_case);
 703                        if (ce && ce_stage(ce) == 0 && strcmp(path, ce->name))
 704                                return 0;
 705                }
 706                if (remove_path(path))
 707                        return -1;
 708        }
 709        return 0;
 710}
 711
 712/* add a string to a strbuf, but converting "/" to "_" */
 713static void add_flattened_path(struct strbuf *out, const char *s)
 714{
 715        size_t i = out->len;
 716        strbuf_addstr(out, s);
 717        for (; i < out->len; i++)
 718                if (out->buf[i] == '/')
 719                        out->buf[i] = '_';
 720}
 721
 722static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 723{
 724        struct path_hashmap_entry *entry;
 725        struct strbuf newpath = STRBUF_INIT;
 726        int suffix = 0;
 727        size_t base_len;
 728
 729        strbuf_addf(&newpath, "%s~", path);
 730        add_flattened_path(&newpath, branch);
 731
 732        base_len = newpath.len;
 733        while (hashmap_get_from_hash(&o->current_file_dir_set,
 734                                     path_hash(newpath.buf), newpath.buf) ||
 735               (!o->call_depth && file_exists(newpath.buf))) {
 736                strbuf_setlen(&newpath, base_len);
 737                strbuf_addf(&newpath, "_%d", suffix++);
 738        }
 739
 740        FLEX_ALLOC_MEM(entry, path, newpath.buf, newpath.len);
 741        hashmap_entry_init(entry, path_hash(entry->path));
 742        hashmap_add(&o->current_file_dir_set, entry);
 743        return strbuf_detach(&newpath, NULL);
 744}
 745
 746/**
 747 * Check whether a directory in the index is in the way of an incoming
 748 * file.  Return 1 if so.  If check_working_copy is non-zero, also
 749 * check the working directory.  If empty_ok is non-zero, also return
 750 * 0 in the case where the working-tree dir exists but is empty.
 751 */
 752static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
 753{
 754        int pos;
 755        struct strbuf dirpath = STRBUF_INIT;
 756        struct stat st;
 757
 758        strbuf_addstr(&dirpath, path);
 759        strbuf_addch(&dirpath, '/');
 760
 761        pos = cache_name_pos(dirpath.buf, dirpath.len);
 762
 763        if (pos < 0)
 764                pos = -1 - pos;
 765        if (pos < active_nr &&
 766            !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
 767                strbuf_release(&dirpath);
 768                return 1;
 769        }
 770
 771        strbuf_release(&dirpath);
 772        return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
 773                !(empty_ok && is_empty_dir(path));
 774}
 775
 776static int was_tracked(const char *path)
 777{
 778        int pos = cache_name_pos(path, strlen(path));
 779
 780        if (0 <= pos)
 781                /* we have been tracking this path */
 782                return 1;
 783
 784        /*
 785         * Look for an unmerged entry for the path,
 786         * specifically stage #2, which would indicate
 787         * that "our" side before the merge started
 788         * had the path tracked (and resulted in a conflict).
 789         */
 790        for (pos = -1 - pos;
 791             pos < active_nr && !strcmp(path, active_cache[pos]->name);
 792             pos++)
 793                if (ce_stage(active_cache[pos]) == 2)
 794                        return 1;
 795        return 0;
 796}
 797
 798static int would_lose_untracked(const char *path)
 799{
 800        return !was_tracked(path) && file_exists(path);
 801}
 802
 803static int was_dirty(struct merge_options *o, const char *path)
 804{
 805        struct cache_entry *ce;
 806        int dirty = 1;
 807
 808        if (o->call_depth || !was_tracked(path))
 809                return !dirty;
 810
 811        ce = cache_file_exists(path, strlen(path), ignore_case);
 812        dirty = (ce->ce_stat_data.sd_mtime.sec > 0 &&
 813                 verify_uptodate(ce, &o->unpack_opts) != 0);
 814        return dirty;
 815}
 816
 817static int make_room_for_path(struct merge_options *o, const char *path)
 818{
 819        int status, i;
 820        const char *msg = _("failed to create path '%s'%s");
 821
 822        /* Unlink any D/F conflict files that are in the way */
 823        for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 824                const char *df_path = o->df_conflict_file_set.items[i].string;
 825                size_t pathlen = strlen(path);
 826                size_t df_pathlen = strlen(df_path);
 827                if (df_pathlen < pathlen &&
 828                    path[df_pathlen] == '/' &&
 829                    strncmp(path, df_path, df_pathlen) == 0) {
 830                        output(o, 3,
 831                               _("Removing %s to make room for subdirectory\n"),
 832                               df_path);
 833                        unlink(df_path);
 834                        unsorted_string_list_delete_item(&o->df_conflict_file_set,
 835                                                         i, 0);
 836                        break;
 837                }
 838        }
 839
 840        /* Make sure leading directories are created */
 841        status = safe_create_leading_directories_const(path);
 842        if (status) {
 843                if (status == SCLD_EXISTS)
 844                        /* something else exists */
 845                        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 846                return err(o, msg, path, "");
 847        }
 848
 849        /*
 850         * Do not unlink a file in the work tree if we are not
 851         * tracking it.
 852         */
 853        if (would_lose_untracked(path))
 854                return err(o, _("refusing to lose untracked file at '%s'"),
 855                             path);
 856
 857        /* Successful unlink is good.. */
 858        if (!unlink(path))
 859                return 0;
 860        /* .. and so is no existing file */
 861        if (errno == ENOENT)
 862                return 0;
 863        /* .. but not some other error (who really cares what?) */
 864        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 865}
 866
 867static int update_file_flags(struct merge_options *o,
 868                             const struct object_id *oid,
 869                             unsigned mode,
 870                             const char *path,
 871                             int update_cache,
 872                             int update_wd)
 873{
 874        int ret = 0;
 875
 876        if (o->call_depth)
 877                update_wd = 0;
 878
 879        if (update_wd) {
 880                enum object_type type;
 881                void *buf;
 882                unsigned long size;
 883
 884                if (S_ISGITLINK(mode)) {
 885                        /*
 886                         * We may later decide to recursively descend into
 887                         * the submodule directory and update its index
 888                         * and/or work tree, but we do not do that now.
 889                         */
 890                        update_wd = 0;
 891                        goto update_index;
 892                }
 893
 894                buf = read_sha1_file(oid->hash, &type, &size);
 895                if (!buf)
 896                        return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 897                if (type != OBJ_BLOB) {
 898                        ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 899                        goto free_buf;
 900                }
 901                if (S_ISREG(mode)) {
 902                        struct strbuf strbuf = STRBUF_INIT;
 903                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 904                                free(buf);
 905                                size = strbuf.len;
 906                                buf = strbuf_detach(&strbuf, NULL);
 907                        }
 908                }
 909
 910                if (make_room_for_path(o, path) < 0) {
 911                        update_wd = 0;
 912                        goto free_buf;
 913                }
 914                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 915                        int fd;
 916                        if (mode & 0100)
 917                                mode = 0777;
 918                        else
 919                                mode = 0666;
 920                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 921                        if (fd < 0) {
 922                                ret = err(o, _("failed to open '%s': %s"),
 923                                          path, strerror(errno));
 924                                goto free_buf;
 925                        }
 926                        write_in_full(fd, buf, size);
 927                        close(fd);
 928                } else if (S_ISLNK(mode)) {
 929                        char *lnk = xmemdupz(buf, size);
 930                        safe_create_leading_directories_const(path);
 931                        unlink(path);
 932                        if (symlink(lnk, path))
 933                                ret = err(o, _("failed to symlink '%s': %s"),
 934                                        path, strerror(errno));
 935                        free(lnk);
 936                } else
 937                        ret = err(o,
 938                                  _("do not know what to do with %06o %s '%s'"),
 939                                  mode, oid_to_hex(oid), path);
 940 free_buf:
 941                free(buf);
 942        }
 943 update_index:
 944        if (!ret && update_cache)
 945                add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 946        return ret;
 947}
 948
 949static int update_file(struct merge_options *o,
 950                       int clean,
 951                       const struct object_id *oid,
 952                       unsigned mode,
 953                       const char *path)
 954{
 955        return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
 956}
 957
 958/* Low level file merging, update and removal */
 959
 960struct merge_file_info {
 961        struct object_id oid;
 962        unsigned mode;
 963        unsigned clean:1,
 964                 merge:1;
 965};
 966
 967static int merge_3way(struct merge_options *o,
 968                      mmbuffer_t *result_buf,
 969                      const struct diff_filespec *one,
 970                      const struct diff_filespec *a,
 971                      const struct diff_filespec *b,
 972                      const char *branch1,
 973                      const char *branch2)
 974{
 975        mmfile_t orig, src1, src2;
 976        struct ll_merge_options ll_opts = {0};
 977        char *base_name, *name1, *name2;
 978        int merge_status;
 979
 980        ll_opts.renormalize = o->renormalize;
 981        ll_opts.xdl_opts = o->xdl_opts;
 982
 983        if (o->call_depth) {
 984                ll_opts.virtual_ancestor = 1;
 985                ll_opts.variant = 0;
 986        } else {
 987                switch (o->recursive_variant) {
 988                case MERGE_RECURSIVE_OURS:
 989                        ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 990                        break;
 991                case MERGE_RECURSIVE_THEIRS:
 992                        ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 993                        break;
 994                default:
 995                        ll_opts.variant = 0;
 996                        break;
 997                }
 998        }
 999
1000        if (strcmp(a->path, b->path) ||
1001            (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
1002                base_name = o->ancestor == NULL ? NULL :
1003                        mkpathdup("%s:%s", o->ancestor, one->path);
1004                name1 = mkpathdup("%s:%s", branch1, a->path);
1005                name2 = mkpathdup("%s:%s", branch2, b->path);
1006        } else {
1007                base_name = o->ancestor == NULL ? NULL :
1008                        mkpathdup("%s", o->ancestor);
1009                name1 = mkpathdup("%s", branch1);
1010                name2 = mkpathdup("%s", branch2);
1011        }
1012
1013        read_mmblob(&orig, &one->oid);
1014        read_mmblob(&src1, &a->oid);
1015        read_mmblob(&src2, &b->oid);
1016
1017        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
1018                                &src1, name1, &src2, name2, &ll_opts);
1019
1020        free(base_name);
1021        free(name1);
1022        free(name2);
1023        free(orig.ptr);
1024        free(src1.ptr);
1025        free(src2.ptr);
1026        return merge_status;
1027}
1028
1029static int merge_file_1(struct merge_options *o,
1030                                           const struct diff_filespec *one,
1031                                           const struct diff_filespec *a,
1032                                           const struct diff_filespec *b,
1033                                           const char *branch1,
1034                                           const char *branch2,
1035                                           struct merge_file_info *result)
1036{
1037        result->merge = 0;
1038        result->clean = 1;
1039
1040        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
1041                result->clean = 0;
1042                if (S_ISREG(a->mode)) {
1043                        result->mode = a->mode;
1044                        oidcpy(&result->oid, &a->oid);
1045                } else {
1046                        result->mode = b->mode;
1047                        oidcpy(&result->oid, &b->oid);
1048                }
1049        } else {
1050                if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
1051                        result->merge = 1;
1052
1053                /*
1054                 * Merge modes
1055                 */
1056                if (a->mode == b->mode || a->mode == one->mode)
1057                        result->mode = b->mode;
1058                else {
1059                        result->mode = a->mode;
1060                        if (b->mode != one->mode) {
1061                                result->clean = 0;
1062                                result->merge = 1;
1063                        }
1064                }
1065
1066                if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
1067                        oidcpy(&result->oid, &b->oid);
1068                else if (oid_eq(&b->oid, &one->oid))
1069                        oidcpy(&result->oid, &a->oid);
1070                else if (S_ISREG(a->mode)) {
1071                        mmbuffer_t result_buf;
1072                        int ret = 0, merge_status;
1073
1074                        merge_status = merge_3way(o, &result_buf, one, a, b,
1075                                                  branch1, branch2);
1076
1077                        if ((merge_status < 0) || !result_buf.ptr)
1078                                ret = err(o, _("Failed to execute internal merge"));
1079
1080                        if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
1081                                                    blob_type, result->oid.hash))
1082                                ret = err(o, _("Unable to add %s to database"),
1083                                          a->path);
1084
1085                        free(result_buf.ptr);
1086                        if (ret)
1087                                return ret;
1088                        result->clean = (merge_status == 0);
1089                } else if (S_ISGITLINK(a->mode)) {
1090                        result->clean = merge_submodule(&result->oid,
1091                                                       one->path,
1092                                                       &one->oid,
1093                                                       &a->oid,
1094                                                       &b->oid,
1095                                                       !o->call_depth);
1096                } else if (S_ISLNK(a->mode)) {
1097                        oidcpy(&result->oid, &a->oid);
1098
1099                        if (!oid_eq(&a->oid, &b->oid))
1100                                result->clean = 0;
1101                } else
1102                        die("BUG: unsupported object type in the tree");
1103        }
1104
1105        return 0;
1106}
1107
1108static int merge_file_special_markers(struct merge_options *o,
1109                           const struct diff_filespec *one,
1110                           const struct diff_filespec *a,
1111                           const struct diff_filespec *b,
1112                           const char *branch1,
1113                           const char *filename1,
1114                           const char *branch2,
1115                           const char *filename2,
1116                           struct merge_file_info *mfi)
1117{
1118        char *side1 = NULL;
1119        char *side2 = NULL;
1120        int ret;
1121
1122        if (filename1)
1123                side1 = xstrfmt("%s:%s", branch1, filename1);
1124        if (filename2)
1125                side2 = xstrfmt("%s:%s", branch2, filename2);
1126
1127        ret = merge_file_1(o, one, a, b,
1128                           side1 ? side1 : branch1,
1129                           side2 ? side2 : branch2, mfi);
1130        free(side1);
1131        free(side2);
1132        return ret;
1133}
1134
1135static int merge_file_one(struct merge_options *o,
1136                                         const char *path,
1137                                         const struct object_id *o_oid, int o_mode,
1138                                         const struct object_id *a_oid, int a_mode,
1139                                         const struct object_id *b_oid, int b_mode,
1140                                         const char *branch1,
1141                                         const char *branch2,
1142                                         struct merge_file_info *mfi)
1143{
1144        struct diff_filespec one, a, b;
1145
1146        one.path = a.path = b.path = (char *)path;
1147        oidcpy(&one.oid, o_oid);
1148        one.mode = o_mode;
1149        oidcpy(&a.oid, a_oid);
1150        a.mode = a_mode;
1151        oidcpy(&b.oid, b_oid);
1152        b.mode = b_mode;
1153        return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
1154}
1155
1156static int conflict_rename_dir(struct merge_options *o,
1157                               struct diff_filepair *pair,
1158                               const char *rename_branch,
1159                               const char *other_branch)
1160{
1161        const struct diff_filespec *dest = pair->two;
1162
1163        if (!o->call_depth && would_lose_untracked(dest->path)) {
1164                char *alt_path = unique_path(o, dest->path, rename_branch);
1165
1166                output(o, 1, _("Error: Refusing to lose untracked file at %s; "
1167                               "writing to %s instead."),
1168                       dest->path, alt_path);
1169                /*
1170                 * Write the file in worktree at alt_path, but not in the
1171                 * index.  Instead, write to dest->path for the index but
1172                 * only at the higher appropriate stage.
1173                 */
1174                if (update_file(o, 0, &dest->oid, dest->mode, alt_path))
1175                        return -1;
1176                free(alt_path);
1177                return update_stages(o, dest->path, NULL,
1178                                     rename_branch == o->branch1 ? dest : NULL,
1179                                     rename_branch == o->branch1 ? NULL : dest);
1180        }
1181
1182        /* Update dest->path both in index and in worktree */
1183        if (update_file(o, 1, &dest->oid, dest->mode, dest->path))
1184                return -1;
1185        return 0;
1186}
1187
1188static int handle_change_delete(struct merge_options *o,
1189                                 const char *path, const char *old_path,
1190                                 const struct object_id *o_oid, int o_mode,
1191                                 const struct object_id *changed_oid,
1192                                 int changed_mode,
1193                                 const char *change_branch,
1194                                 const char *delete_branch,
1195                                 const char *change, const char *change_past)
1196{
1197        char *alt_path = NULL;
1198        const char *update_path = path;
1199        int ret = 0;
1200
1201        if (dir_in_way(path, !o->call_depth, 0) ||
1202            (!o->call_depth && would_lose_untracked(path))) {
1203                update_path = alt_path = unique_path(o, path, change_branch);
1204        }
1205
1206        if (o->call_depth) {
1207                /*
1208                 * We cannot arbitrarily accept either a_sha or b_sha as
1209                 * correct; since there is no true "middle point" between
1210                 * them, simply reuse the base version for virtual merge base.
1211                 */
1212                ret = remove_file_from_cache(path);
1213                if (!ret)
1214                        ret = update_file(o, 0, o_oid, o_mode, update_path);
1215        } else {
1216                if (!alt_path) {
1217                        if (!old_path) {
1218                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1219                                       "and %s in %s. Version %s of %s left in tree."),
1220                                       change, path, delete_branch, change_past,
1221                                       change_branch, change_branch, path);
1222                        } else {
1223                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1224                                       "and %s to %s in %s. Version %s of %s left in tree."),
1225                                       change, old_path, delete_branch, change_past, path,
1226                                       change_branch, change_branch, path);
1227                        }
1228                } else {
1229                        if (!old_path) {
1230                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1231                                       "and %s in %s. Version %s of %s left in tree at %s."),
1232                                       change, path, delete_branch, change_past,
1233                                       change_branch, change_branch, path, alt_path);
1234                        } else {
1235                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1236                                       "and %s to %s in %s. Version %s of %s left in tree at %s."),
1237                                       change, old_path, delete_branch, change_past, path,
1238                                       change_branch, change_branch, path, alt_path);
1239                        }
1240                }
1241                /*
1242                 * No need to call update_file() on path when change_branch ==
1243                 * o->branch1 && !alt_path, since that would needlessly touch
1244                 * path.  We could call update_file_flags() with update_cache=0
1245                 * and update_wd=0, but that's a no-op.
1246                 */
1247                if (change_branch != o->branch1 || alt_path)
1248                        ret = update_file(o, 0, changed_oid, changed_mode, update_path);
1249        }
1250        free(alt_path);
1251
1252        return ret;
1253}
1254
1255static int conflict_rename_delete(struct merge_options *o,
1256                                   struct diff_filepair *pair,
1257                                   const char *rename_branch,
1258                                   const char *delete_branch)
1259{
1260        const struct diff_filespec *orig = pair->one;
1261        const struct diff_filespec *dest = pair->two;
1262
1263        if (handle_change_delete(o,
1264                                 o->call_depth ? orig->path : dest->path,
1265                                 o->call_depth ? NULL : orig->path,
1266                                 &orig->oid, orig->mode,
1267                                 &dest->oid, dest->mode,
1268                                 rename_branch, delete_branch,
1269                                 _("rename"), _("renamed")))
1270                return -1;
1271
1272        if (o->call_depth)
1273                return remove_file_from_cache(dest->path);
1274        else
1275                return update_stages(o, dest->path, NULL,
1276                                     rename_branch == o->branch1 ? dest : NULL,
1277                                     rename_branch == o->branch1 ? NULL : dest);
1278}
1279
1280static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1281                                                 struct stage_data *entry,
1282                                                 int stage)
1283{
1284        struct object_id *oid = &entry->stages[stage].oid;
1285        unsigned mode = entry->stages[stage].mode;
1286        if (mode == 0 || is_null_oid(oid))
1287                return NULL;
1288        oidcpy(&target->oid, oid);
1289        target->mode = mode;
1290        return target;
1291}
1292
1293static int handle_file(struct merge_options *o,
1294                        struct diff_filespec *rename,
1295                        int stage,
1296                        struct rename_conflict_info *ci)
1297{
1298        char *dst_name = rename->path;
1299        struct stage_data *dst_entry;
1300        const char *cur_branch, *other_branch;
1301        struct diff_filespec other;
1302        struct diff_filespec *add;
1303        int ret;
1304
1305        if (stage == 2) {
1306                dst_entry = ci->dst_entry1;
1307                cur_branch = ci->branch1;
1308                other_branch = ci->branch2;
1309        } else {
1310                dst_entry = ci->dst_entry2;
1311                cur_branch = ci->branch2;
1312                other_branch = ci->branch1;
1313        }
1314
1315        add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1316        if (add) {
1317                char *add_name = unique_path(o, rename->path, other_branch);
1318                if (update_file(o, 0, &add->oid, add->mode, add_name))
1319                        return -1;
1320
1321                remove_file(o, 0, rename->path, 0);
1322                dst_name = unique_path(o, rename->path, cur_branch);
1323        } else {
1324                if (dir_in_way(rename->path, !o->call_depth, 0)) {
1325                        dst_name = unique_path(o, rename->path, cur_branch);
1326                        output(o, 1, _("%s is a directory in %s adding as %s instead"),
1327                               rename->path, other_branch, dst_name);
1328                } else if (!o->call_depth &&
1329                           would_lose_untracked(rename->path)) {
1330                        dst_name = unique_path(o, rename->path, cur_branch);
1331                        output(o, 1, _("Refusing to lose untracked file at %s; "
1332                                       "adding as %s instead"),
1333                               rename->path, dst_name);
1334                }
1335        }
1336        if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
1337                ; /* fall through, do allow dst_name to be released */
1338        else if (stage == 2)
1339                ret = update_stages(o, rename->path, NULL, rename, add);
1340        else
1341                ret = update_stages(o, rename->path, NULL, add, rename);
1342
1343        if (dst_name != rename->path)
1344                free(dst_name);
1345
1346        return ret;
1347}
1348
1349static int conflict_rename_rename_1to2(struct merge_options *o,
1350                                        struct rename_conflict_info *ci)
1351{
1352        /* One file was renamed in both branches, but to different names. */
1353        struct diff_filespec *one = ci->pair1->one;
1354        struct diff_filespec *a = ci->pair1->two;
1355        struct diff_filespec *b = ci->pair2->two;
1356
1357        output(o, 1, _("CONFLICT (rename/rename): "
1358               "Rename \"%s\"->\"%s\" in branch \"%s\" "
1359               "rename \"%s\"->\"%s\" in \"%s\"%s"),
1360               one->path, a->path, ci->branch1,
1361               one->path, b->path, ci->branch2,
1362               o->call_depth ? _(" (left unresolved)") : "");
1363        if (o->call_depth) {
1364                struct merge_file_info mfi;
1365                struct diff_filespec other;
1366                struct diff_filespec *add;
1367                if (merge_file_one(o, one->path,
1368                                 &one->oid, one->mode,
1369                                 &a->oid, a->mode,
1370                                 &b->oid, b->mode,
1371                                 ci->branch1, ci->branch2, &mfi))
1372                        return -1;
1373
1374                /*
1375                 * FIXME: For rename/add-source conflicts (if we could detect
1376                 * such), this is wrong.  We should instead find a unique
1377                 * pathname and then either rename the add-source file to that
1378                 * unique path, or use that unique path instead of src here.
1379                 */
1380                if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
1381                        return -1;
1382
1383                /*
1384                 * Above, we put the merged content at the merge-base's
1385                 * path.  Now we usually need to delete both a->path and
1386                 * b->path.  However, the rename on each side of the merge
1387                 * could also be involved in a rename/add conflict.  In
1388                 * such cases, we should keep the added file around,
1389                 * resolving the conflict at that path in its favor.
1390                 */
1391                add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1392                if (add) {
1393                        if (update_file(o, 0, &add->oid, add->mode, a->path))
1394                                return -1;
1395                }
1396                else
1397                        remove_file_from_cache(a->path);
1398                add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1399                if (add) {
1400                        if (update_file(o, 0, &add->oid, add->mode, b->path))
1401                                return -1;
1402                }
1403                else
1404                        remove_file_from_cache(b->path);
1405        } else if (handle_file(o, a, 2, ci) || handle_file(o, b, 3, ci))
1406                return -1;
1407
1408        return 0;
1409}
1410
1411static int conflict_rename_rename_2to1(struct merge_options *o,
1412                                        struct rename_conflict_info *ci)
1413{
1414        /* Two files, a & b, were renamed to the same thing, c. */
1415        struct diff_filespec *a = ci->pair1->one;
1416        struct diff_filespec *b = ci->pair2->one;
1417        struct diff_filespec *c1 = ci->pair1->two;
1418        struct diff_filespec *c2 = ci->pair2->two;
1419        char *path = c1->path; /* == c2->path */
1420        struct merge_file_info mfi_c1;
1421        struct merge_file_info mfi_c2;
1422        int ret;
1423
1424        output(o, 1, _("CONFLICT (rename/rename): "
1425               "Rename %s->%s in %s. "
1426               "Rename %s->%s in %s"),
1427               a->path, c1->path, ci->branch1,
1428               b->path, c2->path, ci->branch2);
1429
1430        remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1431        remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1432
1433        if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
1434                                       o->branch1, c1->path,
1435                                       o->branch2, ci->ren1_other.path, &mfi_c1) ||
1436            merge_file_special_markers(o, b, &ci->ren2_other, c2,
1437                                       o->branch1, ci->ren2_other.path,
1438                                       o->branch2, c2->path, &mfi_c2))
1439                return -1;
1440
1441        if (o->call_depth) {
1442                /*
1443                 * If mfi_c1.clean && mfi_c2.clean, then it might make
1444                 * sense to do a two-way merge of those results.  But, I
1445                 * think in all cases, it makes sense to have the virtual
1446                 * merge base just undo the renames; they can be detected
1447                 * again later for the non-recursive merge.
1448                 */
1449                remove_file(o, 0, path, 0);
1450                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, a->path);
1451                if (!ret)
1452                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1453                                          b->path);
1454        } else {
1455                char *new_path1 = unique_path(o, path, ci->branch1);
1456                char *new_path2 = unique_path(o, path, ci->branch2);
1457                output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1458                       a->path, new_path1, b->path, new_path2);
1459                if (would_lose_untracked(path))
1460                        /*
1461                         * Only way we get here is if both renames were from
1462                         * a directory rename AND user had an untracked file
1463                         * at the location where both files end up after the
1464                         * two directory renames.  See testcase 10d of t6043.
1465                         */
1466                        output(o, 1, _("Refusing to lose untracked file at "
1467                                       "%s, even though it's in the way."),
1468                               path);
1469                else
1470                        remove_file(o, 0, path, 0);
1471                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
1472                if (!ret)
1473                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1474                                          new_path2);
1475                /*
1476                 * unpack_trees() actually populates the index for us for
1477                 * "normal" rename/rename(2to1) situtations so that the
1478                 * correct entries are at the higher stages, which would
1479                 * make the call below to update_stages_for_stage_data
1480                 * unnecessary.  However, if either of the renames came
1481                 * from a directory rename, then unpack_trees() will not
1482                 * have gotten the right data loaded into the index, so we
1483                 * need to do so now.  (While it'd be tempting to move this
1484                 * call to update_stages_for_stage_data() to
1485                 * apply_directory_rename_modifications(), that would break
1486                 * our intermediate calls to would_lose_untracked() since
1487                 * those rely on the current in-memory index.  See also the
1488                 * big "NOTE" in update_stages()).
1489                 */
1490                if (update_stages_for_stage_data(o, path, ci->dst_entry1))
1491                        ret = -1;
1492
1493                free(new_path2);
1494                free(new_path1);
1495        }
1496
1497        return ret;
1498}
1499
1500/*
1501 * Get the diff_filepairs changed between o_tree and tree.
1502 */
1503static struct diff_queue_struct *get_diffpairs(struct merge_options *o,
1504                                               struct tree *o_tree,
1505                                               struct tree *tree)
1506{
1507        struct diff_queue_struct *ret;
1508        struct diff_options opts;
1509
1510        diff_setup(&opts);
1511        opts.flags.recursive = 1;
1512        opts.flags.rename_empty = 0;
1513        opts.detect_rename = DIFF_DETECT_RENAME;
1514        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
1515                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
1516                            1000;
1517        opts.rename_score = o->rename_score;
1518        opts.show_rename_progress = o->show_rename_progress;
1519        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1520        diff_setup_done(&opts);
1521        diff_tree_oid(&o_tree->object.oid, &tree->object.oid, "", &opts);
1522        diffcore_std(&opts);
1523        if (opts.needed_rename_limit > o->needed_rename_limit)
1524                o->needed_rename_limit = opts.needed_rename_limit;
1525
1526        ret = xmalloc(sizeof(*ret));
1527        *ret = diff_queued_diff;
1528
1529        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
1530        diff_queued_diff.nr = 0;
1531        diff_queued_diff.queue = NULL;
1532        diff_flush(&opts);
1533        return ret;
1534}
1535
1536static int tree_has_path(struct tree *tree, const char *path)
1537{
1538        unsigned char hashy[GIT_MAX_RAWSZ];
1539        unsigned int mode_o;
1540
1541        return !get_tree_entry(tree->object.oid.hash, path,
1542                               hashy, &mode_o);
1543}
1544
1545/*
1546 * Return a new string that replaces the beginning portion (which matches
1547 * entry->dir), with entry->new_dir.  In perl-speak:
1548 *   new_path_name = (old_path =~ s/entry->dir/entry->new_dir/);
1549 * NOTE:
1550 *   Caller must ensure that old_path starts with entry->dir + '/'.
1551 */
1552static char *apply_dir_rename(struct dir_rename_entry *entry,
1553                              const char *old_path)
1554{
1555        struct strbuf new_path = STRBUF_INIT;
1556        int oldlen, newlen;
1557
1558        if (entry->non_unique_new_dir)
1559                return NULL;
1560
1561        oldlen = strlen(entry->dir);
1562        newlen = entry->new_dir.len + (strlen(old_path) - oldlen) + 1;
1563        strbuf_grow(&new_path, newlen);
1564        strbuf_addbuf(&new_path, &entry->new_dir);
1565        strbuf_addstr(&new_path, &old_path[oldlen]);
1566
1567        return strbuf_detach(&new_path, NULL);
1568}
1569
1570static void get_renamed_dir_portion(const char *old_path, const char *new_path,
1571                                    char **old_dir, char **new_dir)
1572{
1573        char *end_of_old, *end_of_new;
1574        int old_len, new_len;
1575
1576        *old_dir = NULL;
1577        *new_dir = NULL;
1578
1579        /*
1580         * For
1581         *    "a/b/c/d/e/foo.c" -> "a/b/some/thing/else/e/foo.c"
1582         * the "e/foo.c" part is the same, we just want to know that
1583         *    "a/b/c/d" was renamed to "a/b/some/thing/else"
1584         * so, for this example, this function returns "a/b/c/d" in
1585         * *old_dir and "a/b/some/thing/else" in *new_dir.
1586         *
1587         * Also, if the basename of the file changed, we don't care.  We
1588         * want to know which portion of the directory, if any, changed.
1589         */
1590        end_of_old = strrchr(old_path, '/');
1591        end_of_new = strrchr(new_path, '/');
1592
1593        if (end_of_old == NULL || end_of_new == NULL)
1594                return;
1595        while (*--end_of_new == *--end_of_old &&
1596               end_of_old != old_path &&
1597               end_of_new != new_path)
1598                ; /* Do nothing; all in the while loop */
1599        /*
1600         * We've found the first non-matching character in the directory
1601         * paths.  That means the current directory we were comparing
1602         * represents the rename.  Move end_of_old and end_of_new back
1603         * to the full directory name.
1604         */
1605        if (*end_of_old == '/')
1606                end_of_old++;
1607        if (*end_of_old != '/')
1608                end_of_new++;
1609        end_of_old = strchr(end_of_old, '/');
1610        end_of_new = strchr(end_of_new, '/');
1611
1612        /*
1613         * It may have been the case that old_path and new_path were the same
1614         * directory all along.  Don't claim a rename if they're the same.
1615         */
1616        old_len = end_of_old - old_path;
1617        new_len = end_of_new - new_path;
1618
1619        if (old_len != new_len || strncmp(old_path, new_path, old_len)) {
1620                *old_dir = xstrndup(old_path, old_len);
1621                *new_dir = xstrndup(new_path, new_len);
1622        }
1623}
1624
1625static void remove_hashmap_entries(struct hashmap *dir_renames,
1626                                   struct string_list *items_to_remove)
1627{
1628        int i;
1629        struct dir_rename_entry *entry;
1630
1631        for (i = 0; i < items_to_remove->nr; i++) {
1632                entry = items_to_remove->items[i].util;
1633                hashmap_remove(dir_renames, entry, NULL);
1634        }
1635        string_list_clear(items_to_remove, 0);
1636}
1637
1638/*
1639 * See if there is a directory rename for path, and if there are any file
1640 * level conflicts for the renamed location.  If there is a rename and
1641 * there are no conflicts, return the new name.  Otherwise, return NULL.
1642 */
1643static char *handle_path_level_conflicts(struct merge_options *o,
1644                                         const char *path,
1645                                         struct dir_rename_entry *entry,
1646                                         struct hashmap *collisions,
1647                                         struct tree *tree)
1648{
1649        char *new_path = NULL;
1650        struct collision_entry *collision_ent;
1651        int clean = 1;
1652        struct strbuf collision_paths = STRBUF_INIT;
1653
1654        /*
1655         * entry has the mapping of old directory name to new directory name
1656         * that we want to apply to path.
1657         */
1658        new_path = apply_dir_rename(entry, path);
1659
1660        if (!new_path) {
1661                /* This should only happen when entry->non_unique_new_dir set */
1662                if (!entry->non_unique_new_dir)
1663                        BUG("entry->non_unqiue_dir not set and !new_path");
1664                output(o, 1, _("CONFLICT (directory rename split): "
1665                               "Unclear where to place %s because directory "
1666                               "%s was renamed to multiple other directories, "
1667                               "with no destination getting a majority of the "
1668                               "files."),
1669                       path, entry->dir);
1670                clean = 0;
1671                return NULL;
1672        }
1673
1674        /*
1675         * The caller needs to have ensured that it has pre-populated
1676         * collisions with all paths that map to new_path.  Do a quick check
1677         * to ensure that's the case.
1678         */
1679        collision_ent = collision_find_entry(collisions, new_path);
1680        if (collision_ent == NULL)
1681                BUG("collision_ent is NULL");
1682
1683        /*
1684         * Check for one-sided add/add/.../add conflicts, i.e.
1685         * where implicit renames from the other side doing
1686         * directory rename(s) can affect this side of history
1687         * to put multiple paths into the same location.  Warn
1688         * and bail on directory renames for such paths.
1689         */
1690        if (collision_ent->reported_already) {
1691                clean = 0;
1692        } else if (tree_has_path(tree, new_path)) {
1693                collision_ent->reported_already = 1;
1694                strbuf_add_separated_string_list(&collision_paths, ", ",
1695                                                 &collision_ent->source_files);
1696                output(o, 1, _("CONFLICT (implicit dir rename): Existing "
1697                               "file/dir at %s in the way of implicit "
1698                               "directory rename(s) putting the following "
1699                               "path(s) there: %s."),
1700                       new_path, collision_paths.buf);
1701                clean = 0;
1702        } else if (collision_ent->source_files.nr > 1) {
1703                collision_ent->reported_already = 1;
1704                strbuf_add_separated_string_list(&collision_paths, ", ",
1705                                                 &collision_ent->source_files);
1706                output(o, 1, _("CONFLICT (implicit dir rename): Cannot map "
1707                               "more than one path to %s; implicit directory "
1708                               "renames tried to put these paths there: %s"),
1709                       new_path, collision_paths.buf);
1710                clean = 0;
1711        }
1712
1713        /* Free memory we no longer need */
1714        strbuf_release(&collision_paths);
1715        if (!clean && new_path) {
1716                free(new_path);
1717                return NULL;
1718        }
1719
1720        return new_path;
1721}
1722
1723/*
1724 * There are a couple things we want to do at the directory level:
1725 *   1. Check for both sides renaming to the same thing, in order to avoid
1726 *      implicit renaming of files that should be left in place.  (See
1727 *      testcase 6b in t6043 for details.)
1728 *   2. Prune directory renames if there are still files left in the
1729 *      the original directory.  These represent a partial directory rename,
1730 *      i.e. a rename where only some of the files within the directory
1731 *      were renamed elsewhere.  (Technically, this could be done earlier
1732 *      in get_directory_renames(), except that would prevent us from
1733 *      doing the previous check and thus failing testcase 6b.)
1734 *   3. Check for rename/rename(1to2) conflicts (at the directory level).
1735 *      In the future, we could potentially record this info as well and
1736 *      omit reporting rename/rename(1to2) conflicts for each path within
1737 *      the affected directories, thus cleaning up the merge output.
1738 *   NOTE: We do NOT check for rename/rename(2to1) conflicts at the
1739 *         directory level, because merging directories is fine.  If it
1740 *         causes conflicts for files within those merged directories, then
1741 *         that should be detected at the individual path level.
1742 */
1743static void handle_directory_level_conflicts(struct merge_options *o,
1744                                             struct hashmap *dir_re_head,
1745                                             struct tree *head,
1746                                             struct hashmap *dir_re_merge,
1747                                             struct tree *merge)
1748{
1749        struct hashmap_iter iter;
1750        struct dir_rename_entry *head_ent;
1751        struct dir_rename_entry *merge_ent;
1752
1753        struct string_list remove_from_head = STRING_LIST_INIT_NODUP;
1754        struct string_list remove_from_merge = STRING_LIST_INIT_NODUP;
1755
1756        hashmap_iter_init(dir_re_head, &iter);
1757        while ((head_ent = hashmap_iter_next(&iter))) {
1758                merge_ent = dir_rename_find_entry(dir_re_merge, head_ent->dir);
1759                if (merge_ent &&
1760                    !head_ent->non_unique_new_dir &&
1761                    !merge_ent->non_unique_new_dir &&
1762                    !strbuf_cmp(&head_ent->new_dir, &merge_ent->new_dir)) {
1763                        /* 1. Renamed identically; remove it from both sides */
1764                        string_list_append(&remove_from_head,
1765                                           head_ent->dir)->util = head_ent;
1766                        strbuf_release(&head_ent->new_dir);
1767                        string_list_append(&remove_from_merge,
1768                                           merge_ent->dir)->util = merge_ent;
1769                        strbuf_release(&merge_ent->new_dir);
1770                } else if (tree_has_path(head, head_ent->dir)) {
1771                        /* 2. This wasn't a directory rename after all */
1772                        string_list_append(&remove_from_head,
1773                                           head_ent->dir)->util = head_ent;
1774                        strbuf_release(&head_ent->new_dir);
1775                }
1776        }
1777
1778        remove_hashmap_entries(dir_re_head, &remove_from_head);
1779        remove_hashmap_entries(dir_re_merge, &remove_from_merge);
1780
1781        hashmap_iter_init(dir_re_merge, &iter);
1782        while ((merge_ent = hashmap_iter_next(&iter))) {
1783                head_ent = dir_rename_find_entry(dir_re_head, merge_ent->dir);
1784                if (tree_has_path(merge, merge_ent->dir)) {
1785                        /* 2. This wasn't a directory rename after all */
1786                        string_list_append(&remove_from_merge,
1787                                           merge_ent->dir)->util = merge_ent;
1788                } else if (head_ent &&
1789                           !head_ent->non_unique_new_dir &&
1790                           !merge_ent->non_unique_new_dir) {
1791                        /* 3. rename/rename(1to2) */
1792                        /*
1793                         * We can assume it's not rename/rename(1to1) because
1794                         * that was case (1), already checked above.  So we
1795                         * know that head_ent->new_dir and merge_ent->new_dir
1796                         * are different strings.
1797                         */
1798                        output(o, 1, _("CONFLICT (rename/rename): "
1799                                       "Rename directory %s->%s in %s. "
1800                                       "Rename directory %s->%s in %s"),
1801                               head_ent->dir, head_ent->new_dir.buf, o->branch1,
1802                               head_ent->dir, merge_ent->new_dir.buf, o->branch2);
1803                        string_list_append(&remove_from_head,
1804                                           head_ent->dir)->util = head_ent;
1805                        strbuf_release(&head_ent->new_dir);
1806                        string_list_append(&remove_from_merge,
1807                                           merge_ent->dir)->util = merge_ent;
1808                        strbuf_release(&merge_ent->new_dir);
1809                }
1810        }
1811
1812        remove_hashmap_entries(dir_re_head, &remove_from_head);
1813        remove_hashmap_entries(dir_re_merge, &remove_from_merge);
1814}
1815
1816static struct hashmap *get_directory_renames(struct diff_queue_struct *pairs,
1817                                             struct tree *tree)
1818{
1819        struct hashmap *dir_renames;
1820        struct hashmap_iter iter;
1821        struct dir_rename_entry *entry;
1822        int i;
1823
1824        /*
1825         * Typically, we think of a directory rename as all files from a
1826         * certain directory being moved to a target directory.  However,
1827         * what if someone first moved two files from the original
1828         * directory in one commit, and then renamed the directory
1829         * somewhere else in a later commit?  At merge time, we just know
1830         * that files from the original directory went to two different
1831         * places, and that the bulk of them ended up in the same place.
1832         * We want each directory rename to represent where the bulk of the
1833         * files from that directory end up; this function exists to find
1834         * where the bulk of the files went.
1835         *
1836         * The first loop below simply iterates through the list of file
1837         * renames, finding out how often each directory rename pair
1838         * possibility occurs.
1839         */
1840        dir_renames = xmalloc(sizeof(struct hashmap));
1841        dir_rename_init(dir_renames);
1842        for (i = 0; i < pairs->nr; ++i) {
1843                struct string_list_item *item;
1844                int *count;
1845                struct diff_filepair *pair = pairs->queue[i];
1846                char *old_dir, *new_dir;
1847
1848                /* File not part of directory rename if it wasn't renamed */
1849                if (pair->status != 'R')
1850                        continue;
1851
1852                get_renamed_dir_portion(pair->one->path, pair->two->path,
1853                                        &old_dir,        &new_dir);
1854                if (!old_dir)
1855                        /* Directory didn't change at all; ignore this one. */
1856                        continue;
1857
1858                entry = dir_rename_find_entry(dir_renames, old_dir);
1859                if (!entry) {
1860                        entry = xmalloc(sizeof(struct dir_rename_entry));
1861                        dir_rename_entry_init(entry, old_dir);
1862                        hashmap_put(dir_renames, entry);
1863                } else {
1864                        free(old_dir);
1865                }
1866                item = string_list_lookup(&entry->possible_new_dirs, new_dir);
1867                if (!item) {
1868                        item = string_list_insert(&entry->possible_new_dirs,
1869                                                  new_dir);
1870                        item->util = xcalloc(1, sizeof(int));
1871                } else {
1872                        free(new_dir);
1873                }
1874                count = item->util;
1875                *count += 1;
1876        }
1877
1878        /*
1879         * For each directory with files moved out of it, we find out which
1880         * target directory received the most files so we can declare it to
1881         * be the "winning" target location for the directory rename.  This
1882         * winner gets recorded in new_dir.  If there is no winner
1883         * (multiple target directories received the same number of files),
1884         * we set non_unique_new_dir.  Once we've determined the winner (or
1885         * that there is no winner), we no longer need possible_new_dirs.
1886         */
1887        hashmap_iter_init(dir_renames, &iter);
1888        while ((entry = hashmap_iter_next(&iter))) {
1889                int max = 0;
1890                int bad_max = 0;
1891                char *best = NULL;
1892
1893                for (i = 0; i < entry->possible_new_dirs.nr; i++) {
1894                        int *count = entry->possible_new_dirs.items[i].util;
1895
1896                        if (*count == max)
1897                                bad_max = max;
1898                        else if (*count > max) {
1899                                max = *count;
1900                                best = entry->possible_new_dirs.items[i].string;
1901                        }
1902                }
1903                if (bad_max == max)
1904                        entry->non_unique_new_dir = 1;
1905                else {
1906                        assert(entry->new_dir.len == 0);
1907                        strbuf_addstr(&entry->new_dir, best);
1908                }
1909                /*
1910                 * The relevant directory sub-portion of the original full
1911                 * filepaths were xstrndup'ed before inserting into
1912                 * possible_new_dirs, and instead of manually iterating the
1913                 * list and free'ing each, just lie and tell
1914                 * possible_new_dirs that it did the strdup'ing so that it
1915                 * will free them for us.
1916                 */
1917                entry->possible_new_dirs.strdup_strings = 1;
1918                string_list_clear(&entry->possible_new_dirs, 1);
1919        }
1920
1921        return dir_renames;
1922}
1923
1924static struct dir_rename_entry *check_dir_renamed(const char *path,
1925                                                  struct hashmap *dir_renames)
1926{
1927        char temp[PATH_MAX];
1928        char *end;
1929        struct dir_rename_entry *entry;
1930
1931        strcpy(temp, path);
1932        while ((end = strrchr(temp, '/'))) {
1933                *end = '\0';
1934                entry = dir_rename_find_entry(dir_renames, temp);
1935                if (entry)
1936                        return entry;
1937        }
1938        return NULL;
1939}
1940
1941static void compute_collisions(struct hashmap *collisions,
1942                               struct hashmap *dir_renames,
1943                               struct diff_queue_struct *pairs)
1944{
1945        int i;
1946
1947        /*
1948         * Multiple files can be mapped to the same path due to directory
1949         * renames done by the other side of history.  Since that other
1950         * side of history could have merged multiple directories into one,
1951         * if our side of history added the same file basename to each of
1952         * those directories, then all N of them would get implicitly
1953         * renamed by the directory rename detection into the same path,
1954         * and we'd get an add/add/.../add conflict, and all those adds
1955         * from *this* side of history.  This is not representable in the
1956         * index, and users aren't going to easily be able to make sense of
1957         * it.  So we need to provide a good warning about what's
1958         * happening, and fall back to no-directory-rename detection
1959         * behavior for those paths.
1960         *
1961         * See testcases 9e and all of section 5 from t6043 for examples.
1962         */
1963        collision_init(collisions);
1964
1965        for (i = 0; i < pairs->nr; ++i) {
1966                struct dir_rename_entry *dir_rename_ent;
1967                struct collision_entry *collision_ent;
1968                char *new_path;
1969                struct diff_filepair *pair = pairs->queue[i];
1970
1971                if (pair->status == 'D')
1972                        continue;
1973                dir_rename_ent = check_dir_renamed(pair->two->path,
1974                                                   dir_renames);
1975                if (!dir_rename_ent)
1976                        continue;
1977
1978                new_path = apply_dir_rename(dir_rename_ent, pair->two->path);
1979                if (!new_path)
1980                        /*
1981                         * dir_rename_ent->non_unique_new_path is true, which
1982                         * means there is no directory rename for us to use,
1983                         * which means it won't cause us any additional
1984                         * collisions.
1985                         */
1986                        continue;
1987                collision_ent = collision_find_entry(collisions, new_path);
1988                if (!collision_ent) {
1989                        collision_ent = xcalloc(1,
1990                                                sizeof(struct collision_entry));
1991                        hashmap_entry_init(collision_ent, strhash(new_path));
1992                        hashmap_put(collisions, collision_ent);
1993                        collision_ent->target_file = new_path;
1994                } else {
1995                        free(new_path);
1996                }
1997                string_list_insert(&collision_ent->source_files,
1998                                   pair->two->path);
1999        }
2000}
2001
2002static char *check_for_directory_rename(struct merge_options *o,
2003                                        const char *path,
2004                                        struct tree *tree,
2005                                        struct hashmap *dir_renames,
2006                                        struct hashmap *dir_rename_exclusions,
2007                                        struct hashmap *collisions,
2008                                        int *clean_merge)
2009{
2010        char *new_path = NULL;
2011        struct dir_rename_entry *entry = check_dir_renamed(path, dir_renames);
2012        struct dir_rename_entry *oentry = NULL;
2013
2014        if (!entry)
2015                return new_path;
2016
2017        /*
2018         * This next part is a little weird.  We do not want to do an
2019         * implicit rename into a directory we renamed on our side, because
2020         * that will result in a spurious rename/rename(1to2) conflict.  An
2021         * example:
2022         *   Base commit: dumbdir/afile, otherdir/bfile
2023         *   Side 1:      smrtdir/afile, otherdir/bfile
2024         *   Side 2:      dumbdir/afile, dumbdir/bfile
2025         * Here, while working on Side 1, we could notice that otherdir was
2026         * renamed/merged to dumbdir, and change the diff_filepair for
2027         * otherdir/bfile into a rename into dumbdir/bfile.  However, Side
2028         * 2 will notice the rename from dumbdir to smrtdir, and do the
2029         * transitive rename to move it from dumbdir/bfile to
2030         * smrtdir/bfile.  That gives us bfile in dumbdir vs being in
2031         * smrtdir, a rename/rename(1to2) conflict.  We really just want
2032         * the file to end up in smrtdir.  And the way to achieve that is
2033         * to not let Side1 do the rename to dumbdir, since we know that is
2034         * the source of one of our directory renames.
2035         *
2036         * That's why oentry and dir_rename_exclusions is here.
2037         *
2038         * As it turns out, this also prevents N-way transient rename
2039         * confusion; See testcases 9c and 9d of t6043.
2040         */
2041        oentry = dir_rename_find_entry(dir_rename_exclusions, entry->new_dir.buf);
2042        if (oentry) {
2043                output(o, 1, _("WARNING: Avoiding applying %s -> %s rename "
2044                               "to %s, because %s itself was renamed."),
2045                       entry->dir, entry->new_dir.buf, path, entry->new_dir.buf);
2046        } else {
2047                new_path = handle_path_level_conflicts(o, path, entry,
2048                                                       collisions, tree);
2049                *clean_merge &= (new_path != NULL);
2050        }
2051
2052        return new_path;
2053}
2054
2055static void apply_directory_rename_modifications(struct merge_options *o,
2056                                                 struct diff_filepair *pair,
2057                                                 char *new_path,
2058                                                 struct rename *re,
2059                                                 struct tree *tree,
2060                                                 struct tree *o_tree,
2061                                                 struct tree *a_tree,
2062                                                 struct tree *b_tree,
2063                                                 struct string_list *entries,
2064                                                 int *clean)
2065{
2066        struct string_list_item *item;
2067        int stage = (tree == a_tree ? 2 : 3);
2068
2069        /*
2070         * In all cases where we can do directory rename detection,
2071         * unpack_trees() will have read pair->two->path into the
2072         * index and the working copy.  We need to remove it so that
2073         * we can instead place it at new_path.  It is guaranteed to
2074         * not be untracked (unpack_trees() would have errored out
2075         * saying the file would have been overwritten), but it might
2076         * be dirty, though.
2077         */
2078        remove_file(o, 1, pair->two->path, 0 /* no_wd */);
2079
2080        /* Find or create a new re->dst_entry */
2081        item = string_list_lookup(entries, new_path);
2082        if (item) {
2083                /*
2084                 * Since we're renaming on this side of history, and it's
2085                 * due to a directory rename on the other side of history
2086                 * (which we only allow when the directory in question no
2087                 * longer exists on the other side of history), the
2088                 * original entry for re->dst_entry is no longer
2089                 * necessary...
2090                 */
2091                re->dst_entry->processed = 1;
2092
2093                /*
2094                 * ...because we'll be using this new one.
2095                 */
2096                re->dst_entry = item->util;
2097        } else {
2098                /*
2099                 * re->dst_entry is for the before-dir-rename path, and we
2100                 * need it to hold information for the after-dir-rename
2101                 * path.  Before creating a new entry, we need to mark the
2102                 * old one as unnecessary (...unless it is shared by
2103                 * src_entry, i.e. this didn't use to be a rename, in which
2104                 * case we can just allow the normal processing to happen
2105                 * for it).
2106                 */
2107                if (pair->status == 'R')
2108                        re->dst_entry->processed = 1;
2109
2110                re->dst_entry = insert_stage_data(new_path,
2111                                                  o_tree, a_tree, b_tree,
2112                                                  entries);
2113                item = string_list_insert(entries, new_path);
2114                item->util = re->dst_entry;
2115        }
2116
2117        /*
2118         * Update the stage_data with the information about the path we are
2119         * moving into place.  That slot will be empty and available for us
2120         * to write to because of the collision checks in
2121         * handle_path_level_conflicts().  In other words,
2122         * re->dst_entry->stages[stage].oid will be the null_oid, so it's
2123         * open for us to write to.
2124         *
2125         * It may be tempting to actually update the index at this point as
2126         * well, using update_stages_for_stage_data(), but as per the big
2127         * "NOTE" in update_stages(), doing so will modify the current
2128         * in-memory index which will break calls to would_lose_untracked()
2129         * that we need to make.  Instead, we need to just make sure that
2130         * the various conflict_rename_*() functions update the index
2131         * explicitly rather than relying on unpack_trees() to have done it.
2132         */
2133        get_tree_entry(tree->object.oid.hash,
2134                       pair->two->path,
2135                       re->dst_entry->stages[stage].oid.hash,
2136                       &re->dst_entry->stages[stage].mode);
2137
2138        /* Update pair status */
2139        if (pair->status == 'A') {
2140                /*
2141                 * Recording rename information for this add makes it look
2142                 * like a rename/delete conflict.  Make sure we can
2143                 * correctly handle this as an add that was moved to a new
2144                 * directory instead of reporting a rename/delete conflict.
2145                 */
2146                re->add_turned_into_rename = 1;
2147        }
2148        /*
2149         * We don't actually look at pair->status again, but it seems
2150         * pedagogically correct to adjust it.
2151         */
2152        pair->status = 'R';
2153
2154        /*
2155         * Finally, record the new location.
2156         */
2157        pair->two->path = new_path;
2158}
2159
2160/*
2161 * Get information of all renames which occurred in 'pairs', making use of
2162 * any implicit directory renames inferred from the other side of history.
2163 * We need the three trees in the merge ('o_tree', 'a_tree' and 'b_tree')
2164 * to be able to associate the correct cache entries with the rename
2165 * information; tree is always equal to either a_tree or b_tree.
2166 */
2167static struct string_list *get_renames(struct merge_options *o,
2168                                       struct diff_queue_struct *pairs,
2169                                       struct hashmap *dir_renames,
2170                                       struct hashmap *dir_rename_exclusions,
2171                                       struct tree *tree,
2172                                       struct tree *o_tree,
2173                                       struct tree *a_tree,
2174                                       struct tree *b_tree,
2175                                       struct string_list *entries,
2176                                       int *clean_merge)
2177{
2178        int i;
2179        struct hashmap collisions;
2180        struct hashmap_iter iter;
2181        struct collision_entry *e;
2182        struct string_list *renames;
2183
2184        compute_collisions(&collisions, dir_renames, pairs);
2185        renames = xcalloc(1, sizeof(struct string_list));
2186
2187        for (i = 0; i < pairs->nr; ++i) {
2188                struct string_list_item *item;
2189                struct rename *re;
2190                struct diff_filepair *pair = pairs->queue[i];
2191                char *new_path; /* non-NULL only with directory renames */
2192
2193                if (pair->status == 'D') {
2194                        diff_free_filepair(pair);
2195                        continue;
2196                }
2197                new_path = check_for_directory_rename(o, pair->two->path, tree,
2198                                                      dir_renames,
2199                                                      dir_rename_exclusions,
2200                                                      &collisions,
2201                                                      clean_merge);
2202                if (pair->status != 'R' && !new_path) {
2203                        diff_free_filepair(pair);
2204                        continue;
2205                }
2206
2207                re = xmalloc(sizeof(*re));
2208                re->processed = 0;
2209                re->add_turned_into_rename = 0;
2210                re->pair = pair;
2211                item = string_list_lookup(entries, re->pair->one->path);
2212                if (!item)
2213                        re->src_entry = insert_stage_data(re->pair->one->path,
2214                                        o_tree, a_tree, b_tree, entries);
2215                else
2216                        re->src_entry = item->util;
2217
2218                item = string_list_lookup(entries, re->pair->two->path);
2219                if (!item)
2220                        re->dst_entry = insert_stage_data(re->pair->two->path,
2221                                        o_tree, a_tree, b_tree, entries);
2222                else
2223                        re->dst_entry = item->util;
2224                item = string_list_insert(renames, pair->one->path);
2225                item->util = re;
2226                if (new_path)
2227                        apply_directory_rename_modifications(o, pair, new_path,
2228                                                             re, tree, o_tree,
2229                                                             a_tree, b_tree,
2230                                                             entries,
2231                                                             clean_merge);
2232        }
2233
2234        hashmap_iter_init(&collisions, &iter);
2235        while ((e = hashmap_iter_next(&iter))) {
2236                free(e->target_file);
2237                string_list_clear(&e->source_files, 0);
2238        }
2239        hashmap_free(&collisions, 1);
2240        return renames;
2241}
2242
2243static int process_renames(struct merge_options *o,
2244                           struct string_list *a_renames,
2245                           struct string_list *b_renames)
2246{
2247        int clean_merge = 1, i, j;
2248        struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
2249        struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
2250        const struct rename *sre;
2251
2252        for (i = 0; i < a_renames->nr; i++) {
2253                sre = a_renames->items[i].util;
2254                string_list_insert(&a_by_dst, sre->pair->two->path)->util
2255                        = (void *)sre;
2256        }
2257        for (i = 0; i < b_renames->nr; i++) {
2258                sre = b_renames->items[i].util;
2259                string_list_insert(&b_by_dst, sre->pair->two->path)->util
2260                        = (void *)sre;
2261        }
2262
2263        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
2264                struct string_list *renames1, *renames2Dst;
2265                struct rename *ren1 = NULL, *ren2 = NULL;
2266                const char *branch1, *branch2;
2267                const char *ren1_src, *ren1_dst;
2268                struct string_list_item *lookup;
2269
2270                if (i >= a_renames->nr) {
2271                        ren2 = b_renames->items[j++].util;
2272                } else if (j >= b_renames->nr) {
2273                        ren1 = a_renames->items[i++].util;
2274                } else {
2275                        int compare = strcmp(a_renames->items[i].string,
2276                                             b_renames->items[j].string);
2277                        if (compare <= 0)
2278                                ren1 = a_renames->items[i++].util;
2279                        if (compare >= 0)
2280                                ren2 = b_renames->items[j++].util;
2281                }
2282
2283                /* TODO: refactor, so that 1/2 are not needed */
2284                if (ren1) {
2285                        renames1 = a_renames;
2286                        renames2Dst = &b_by_dst;
2287                        branch1 = o->branch1;
2288                        branch2 = o->branch2;
2289                } else {
2290                        renames1 = b_renames;
2291                        renames2Dst = &a_by_dst;
2292                        branch1 = o->branch2;
2293                        branch2 = o->branch1;
2294                        SWAP(ren2, ren1);
2295                }
2296
2297                if (ren1->processed)
2298                        continue;
2299                ren1->processed = 1;
2300                ren1->dst_entry->processed = 1;
2301                /* BUG: We should only mark src_entry as processed if we
2302                 * are not dealing with a rename + add-source case.
2303                 */
2304                ren1->src_entry->processed = 1;
2305
2306                ren1_src = ren1->pair->one->path;
2307                ren1_dst = ren1->pair->two->path;
2308
2309                if (ren2) {
2310                        /* One file renamed on both sides */
2311                        const char *ren2_src = ren2->pair->one->path;
2312                        const char *ren2_dst = ren2->pair->two->path;
2313                        enum rename_type rename_type;
2314                        if (strcmp(ren1_src, ren2_src) != 0)
2315                                die("BUG: ren1_src != ren2_src");
2316                        ren2->dst_entry->processed = 1;
2317                        ren2->processed = 1;
2318                        if (strcmp(ren1_dst, ren2_dst) != 0) {
2319                                rename_type = RENAME_ONE_FILE_TO_TWO;
2320                                clean_merge = 0;
2321                        } else {
2322                                rename_type = RENAME_ONE_FILE_TO_ONE;
2323                                /* BUG: We should only remove ren1_src in
2324                                 * the base stage (think of rename +
2325                                 * add-source cases).
2326                                 */
2327                                remove_file(o, 1, ren1_src, 1);
2328                                update_entry(ren1->dst_entry,
2329                                             ren1->pair->one,
2330                                             ren1->pair->two,
2331                                             ren2->pair->two);
2332                        }
2333                        setup_rename_conflict_info(rename_type,
2334                                                   ren1->pair,
2335                                                   ren2->pair,
2336                                                   branch1,
2337                                                   branch2,
2338                                                   ren1->dst_entry,
2339                                                   ren2->dst_entry,
2340                                                   o,
2341                                                   NULL,
2342                                                   NULL);
2343                } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
2344                        /* Two different files renamed to the same thing */
2345                        char *ren2_dst;
2346                        ren2 = lookup->util;
2347                        ren2_dst = ren2->pair->two->path;
2348                        if (strcmp(ren1_dst, ren2_dst) != 0)
2349                                die("BUG: ren1_dst != ren2_dst");
2350
2351                        clean_merge = 0;
2352                        ren2->processed = 1;
2353                        /*
2354                         * BUG: We should only mark src_entry as processed
2355                         * if we are not dealing with a rename + add-source
2356                         * case.
2357                         */
2358                        ren2->src_entry->processed = 1;
2359
2360                        setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
2361                                                   ren1->pair,
2362                                                   ren2->pair,
2363                                                   branch1,
2364                                                   branch2,
2365                                                   ren1->dst_entry,
2366                                                   ren2->dst_entry,
2367                                                   o,
2368                                                   ren1->src_entry,
2369                                                   ren2->src_entry);
2370
2371                } else {
2372                        /* Renamed in 1, maybe changed in 2 */
2373                        /* we only use sha1 and mode of these */
2374                        struct diff_filespec src_other, dst_other;
2375                        int try_merge;
2376
2377                        /*
2378                         * unpack_trees loads entries from common-commit
2379                         * into stage 1, from head-commit into stage 2, and
2380                         * from merge-commit into stage 3.  We keep track
2381                         * of which side corresponds to the rename.
2382                         */
2383                        int renamed_stage = a_renames == renames1 ? 2 : 3;
2384                        int other_stage =   a_renames == renames1 ? 3 : 2;
2385
2386                        /* BUG: We should only remove ren1_src in the base
2387                         * stage and in other_stage (think of rename +
2388                         * add-source case).
2389                         */
2390                        remove_file(o, 1, ren1_src,
2391                                    renamed_stage == 2 || !was_tracked(ren1_src));
2392
2393                        oidcpy(&src_other.oid,
2394                               &ren1->src_entry->stages[other_stage].oid);
2395                        src_other.mode = ren1->src_entry->stages[other_stage].mode;
2396                        oidcpy(&dst_other.oid,
2397                               &ren1->dst_entry->stages[other_stage].oid);
2398                        dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
2399                        try_merge = 0;
2400
2401                        if (oid_eq(&src_other.oid, &null_oid) &&
2402                            ren1->add_turned_into_rename) {
2403                                setup_rename_conflict_info(RENAME_DIR,
2404                                                           ren1->pair,
2405                                                           NULL,
2406                                                           branch1,
2407                                                           branch2,
2408                                                           ren1->dst_entry,
2409                                                           NULL,
2410                                                           o,
2411                                                           NULL,
2412                                                           NULL);
2413                        } else if (oid_eq(&src_other.oid, &null_oid)) {
2414                                setup_rename_conflict_info(RENAME_DELETE,
2415                                                           ren1->pair,
2416                                                           NULL,
2417                                                           branch1,
2418                                                           branch2,
2419                                                           ren1->dst_entry,
2420                                                           NULL,
2421                                                           o,
2422                                                           NULL,
2423                                                           NULL);
2424                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
2425                                   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
2426                                /*
2427                                 * Added file on the other side identical to
2428                                 * the file being renamed: clean merge.
2429                                 * Also, there is no need to overwrite the
2430                                 * file already in the working copy, so call
2431                                 * update_file_flags() instead of
2432                                 * update_file().
2433                                 */
2434                                if (update_file_flags(o,
2435                                                      &ren1->pair->two->oid,
2436                                                      ren1->pair->two->mode,
2437                                                      ren1_dst,
2438                                                      1, /* update_cache */
2439                                                      0  /* update_wd    */))
2440                                        clean_merge = -1;
2441                        } else if (!oid_eq(&dst_other.oid, &null_oid)) {
2442                                clean_merge = 0;
2443                                try_merge = 1;
2444                                output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
2445                                       "%s added in %s"),
2446                                       ren1_src, ren1_dst, branch1,
2447                                       ren1_dst, branch2);
2448                                if (o->call_depth) {
2449                                        struct merge_file_info mfi;
2450                                        if (merge_file_one(o, ren1_dst, &null_oid, 0,
2451                                                           &ren1->pair->two->oid,
2452                                                           ren1->pair->two->mode,
2453                                                           &dst_other.oid,
2454                                                           dst_other.mode,
2455                                                           branch1, branch2, &mfi)) {
2456                                                clean_merge = -1;
2457                                                goto cleanup_and_return;
2458                                        }
2459                                        output(o, 1, _("Adding merged %s"), ren1_dst);
2460                                        if (update_file(o, 0, &mfi.oid,
2461                                                        mfi.mode, ren1_dst))
2462                                                clean_merge = -1;
2463                                        try_merge = 0;
2464                                } else {
2465                                        char *new_path = unique_path(o, ren1_dst, branch2);
2466                                        output(o, 1, _("Adding as %s instead"), new_path);
2467                                        if (update_file(o, 0, &dst_other.oid,
2468                                                        dst_other.mode, new_path))
2469                                                clean_merge = -1;
2470                                        free(new_path);
2471                                }
2472                        } else
2473                                try_merge = 1;
2474
2475                        if (clean_merge < 0)
2476                                goto cleanup_and_return;
2477                        if (try_merge) {
2478                                struct diff_filespec *one, *a, *b;
2479                                src_other.path = (char *)ren1_src;
2480
2481                                one = ren1->pair->one;
2482                                if (a_renames == renames1) {
2483                                        a = ren1->pair->two;
2484                                        b = &src_other;
2485                                } else {
2486                                        b = ren1->pair->two;
2487                                        a = &src_other;
2488                                }
2489                                update_entry(ren1->dst_entry, one, a, b);
2490                                setup_rename_conflict_info(RENAME_NORMAL,
2491                                                           ren1->pair,
2492                                                           NULL,
2493                                                           branch1,
2494                                                           NULL,
2495                                                           ren1->dst_entry,
2496                                                           NULL,
2497                                                           o,
2498                                                           NULL,
2499                                                           NULL);
2500                        }
2501                }
2502        }
2503cleanup_and_return:
2504        string_list_clear(&a_by_dst, 0);
2505        string_list_clear(&b_by_dst, 0);
2506
2507        return clean_merge;
2508}
2509
2510struct rename_info {
2511        struct string_list *head_renames;
2512        struct string_list *merge_renames;
2513};
2514
2515static void initial_cleanup_rename(struct diff_queue_struct *pairs,
2516                                   struct hashmap *dir_renames)
2517{
2518        struct hashmap_iter iter;
2519        struct dir_rename_entry *e;
2520
2521        hashmap_iter_init(dir_renames, &iter);
2522        while ((e = hashmap_iter_next(&iter))) {
2523                free(e->dir);
2524                strbuf_release(&e->new_dir);
2525                /* possible_new_dirs already cleared in get_directory_renames */
2526        }
2527        hashmap_free(dir_renames, 1);
2528        free(dir_renames);
2529
2530        free(pairs->queue);
2531        free(pairs);
2532}
2533
2534static int handle_renames(struct merge_options *o,
2535                          struct tree *common,
2536                          struct tree *head,
2537                          struct tree *merge,
2538                          struct string_list *entries,
2539                          struct rename_info *ri)
2540{
2541        struct diff_queue_struct *head_pairs, *merge_pairs;
2542        struct hashmap *dir_re_head, *dir_re_merge;
2543        int clean = 1;
2544
2545        ri->head_renames = NULL;
2546        ri->merge_renames = NULL;
2547
2548        if (!o->detect_rename)
2549                return 1;
2550
2551        head_pairs = get_diffpairs(o, common, head);
2552        merge_pairs = get_diffpairs(o, common, merge);
2553
2554        dir_re_head = get_directory_renames(head_pairs, head);
2555        dir_re_merge = get_directory_renames(merge_pairs, merge);
2556
2557        handle_directory_level_conflicts(o,
2558                                         dir_re_head, head,
2559                                         dir_re_merge, merge);
2560
2561        ri->head_renames  = get_renames(o, head_pairs,
2562                                        dir_re_merge, dir_re_head, head,
2563                                        common, head, merge, entries,
2564                                        &clean);
2565        if (clean < 0)
2566                goto cleanup;
2567        ri->merge_renames = get_renames(o, merge_pairs,
2568                                        dir_re_head, dir_re_merge, merge,
2569                                        common, head, merge, entries,
2570                                        &clean);
2571        if (clean < 0)
2572                goto cleanup;
2573        clean &= process_renames(o, ri->head_renames, ri->merge_renames);
2574
2575cleanup:
2576        /*
2577         * Some cleanup is deferred until cleanup_renames() because the
2578         * data structures are still needed and referenced in
2579         * process_entry().  But there are a few things we can free now.
2580         */
2581        initial_cleanup_rename(head_pairs, dir_re_head);
2582        initial_cleanup_rename(merge_pairs, dir_re_merge);
2583
2584        return clean;
2585}
2586
2587static void final_cleanup_rename(struct string_list *rename)
2588{
2589        const struct rename *re;
2590        int i;
2591
2592        if (rename == NULL)
2593                return;
2594
2595        for (i = 0; i < rename->nr; i++) {
2596                re = rename->items[i].util;
2597                diff_free_filepair(re->pair);
2598        }
2599        string_list_clear(rename, 1);
2600        free(rename);
2601}
2602
2603static void final_cleanup_renames(struct rename_info *re_info)
2604{
2605        final_cleanup_rename(re_info->head_renames);
2606        final_cleanup_rename(re_info->merge_renames);
2607}
2608
2609static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
2610{
2611        return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
2612}
2613
2614static int read_oid_strbuf(struct merge_options *o,
2615        const struct object_id *oid, struct strbuf *dst)
2616{
2617        void *buf;
2618        enum object_type type;
2619        unsigned long size;
2620        buf = read_sha1_file(oid->hash, &type, &size);
2621        if (!buf)
2622                return err(o, _("cannot read object %s"), oid_to_hex(oid));
2623        if (type != OBJ_BLOB) {
2624                free(buf);
2625                return err(o, _("object %s is not a blob"), oid_to_hex(oid));
2626        }
2627        strbuf_attach(dst, buf, size, size + 1);
2628        return 0;
2629}
2630
2631static int blob_unchanged(struct merge_options *opt,
2632                          const struct object_id *o_oid,
2633                          unsigned o_mode,
2634                          const struct object_id *a_oid,
2635                          unsigned a_mode,
2636                          int renormalize, const char *path)
2637{
2638        struct strbuf o = STRBUF_INIT;
2639        struct strbuf a = STRBUF_INIT;
2640        int ret = 0; /* assume changed for safety */
2641
2642        if (a_mode != o_mode)
2643                return 0;
2644        if (oid_eq(o_oid, a_oid))
2645                return 1;
2646        if (!renormalize)
2647                return 0;
2648
2649        assert(o_oid && a_oid);
2650        if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
2651                goto error_return;
2652        /*
2653         * Note: binary | is used so that both renormalizations are
2654         * performed.  Comparison can be skipped if both files are
2655         * unchanged since their sha1s have already been compared.
2656         */
2657        if (renormalize_buffer(&the_index, path, o.buf, o.len, &o) |
2658            renormalize_buffer(&the_index, path, a.buf, a.len, &a))
2659                ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
2660
2661error_return:
2662        strbuf_release(&o);
2663        strbuf_release(&a);
2664        return ret;
2665}
2666
2667static int handle_modify_delete(struct merge_options *o,
2668                                 const char *path,
2669                                 struct object_id *o_oid, int o_mode,
2670                                 struct object_id *a_oid, int a_mode,
2671                                 struct object_id *b_oid, int b_mode)
2672{
2673        const char *modify_branch, *delete_branch;
2674        struct object_id *changed_oid;
2675        int changed_mode;
2676
2677        if (a_oid) {
2678                modify_branch = o->branch1;
2679                delete_branch = o->branch2;
2680                changed_oid = a_oid;
2681                changed_mode = a_mode;
2682        } else {
2683                modify_branch = o->branch2;
2684                delete_branch = o->branch1;
2685                changed_oid = b_oid;
2686                changed_mode = b_mode;
2687        }
2688
2689        return handle_change_delete(o,
2690                                    path, NULL,
2691                                    o_oid, o_mode,
2692                                    changed_oid, changed_mode,
2693                                    modify_branch, delete_branch,
2694                                    _("modify"), _("modified"));
2695}
2696
2697static int merge_content(struct merge_options *o,
2698                         const char *path,
2699                         int file_in_way,
2700                         struct object_id *o_oid, int o_mode,
2701                         struct object_id *a_oid, int a_mode,
2702                         struct object_id *b_oid, int b_mode,
2703                         struct rename_conflict_info *rename_conflict_info)
2704{
2705        const char *reason = _("content");
2706        const char *path1 = NULL, *path2 = NULL;
2707        struct merge_file_info mfi;
2708        struct diff_filespec one, a, b;
2709        unsigned df_conflict_remains = 0;
2710
2711        if (!o_oid) {
2712                reason = _("add/add");
2713                o_oid = (struct object_id *)&null_oid;
2714        }
2715        one.path = a.path = b.path = (char *)path;
2716        oidcpy(&one.oid, o_oid);
2717        one.mode = o_mode;
2718        oidcpy(&a.oid, a_oid);
2719        a.mode = a_mode;
2720        oidcpy(&b.oid, b_oid);
2721        b.mode = b_mode;
2722
2723        if (rename_conflict_info) {
2724                struct diff_filepair *pair1 = rename_conflict_info->pair1;
2725
2726                path1 = (o->branch1 == rename_conflict_info->branch1) ?
2727                        pair1->two->path : pair1->one->path;
2728                /* If rename_conflict_info->pair2 != NULL, we are in
2729                 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
2730                 * normal rename.
2731                 */
2732                path2 = (rename_conflict_info->pair2 ||
2733                         o->branch2 == rename_conflict_info->branch1) ?
2734                        pair1->two->path : pair1->one->path;
2735
2736                if (dir_in_way(path, !o->call_depth,
2737                               S_ISGITLINK(pair1->two->mode)))
2738                        df_conflict_remains = 1;
2739        }
2740        if (merge_file_special_markers(o, &one, &a, &b,
2741                                       o->branch1, path1,
2742                                       o->branch2, path2, &mfi))
2743                return -1;
2744
2745        if (mfi.clean && !df_conflict_remains &&
2746            oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
2747                int path_renamed_outside_HEAD;
2748                output(o, 3, _("Skipped %s (merged same as existing)"), path);
2749                /*
2750                 * The content merge resulted in the same file contents we
2751                 * already had.  We can return early if those file contents
2752                 * are recorded at the correct path (which may not be true
2753                 * if the merge involves a rename).
2754                 */
2755                path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
2756                if (!path_renamed_outside_HEAD) {
2757                        add_cacheinfo(o, mfi.mode, &mfi.oid, path,
2758                                      0, (!o->call_depth), 0);
2759                        return mfi.clean;
2760                }
2761        } else
2762                output(o, 2, _("Auto-merging %s"), path);
2763
2764        if (!mfi.clean) {
2765                if (S_ISGITLINK(mfi.mode))
2766                        reason = _("submodule");
2767                output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
2768                                reason, path);
2769                if (rename_conflict_info && !df_conflict_remains)
2770                        if (update_stages(o, path, &one, &a, &b))
2771                                return -1;
2772        }
2773
2774        if (df_conflict_remains || file_in_way) {
2775                char *new_path;
2776                if (o->call_depth) {
2777                        remove_file_from_cache(path);
2778                } else {
2779                        if (!mfi.clean) {
2780                                if (update_stages(o, path, &one, &a, &b))
2781                                        return -1;
2782                        } else {
2783                                int file_from_stage2 = was_tracked(path);
2784                                struct diff_filespec merged;
2785                                oidcpy(&merged.oid, &mfi.oid);
2786                                merged.mode = mfi.mode;
2787
2788                                if (update_stages(o, path, NULL,
2789                                                  file_from_stage2 ? &merged : NULL,
2790                                                  file_from_stage2 ? NULL : &merged))
2791                                        return -1;
2792                        }
2793
2794                }
2795                new_path = unique_path(o, path, rename_conflict_info->branch1);
2796                output(o, 1, _("Adding as %s instead"), new_path);
2797                if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
2798                        free(new_path);
2799                        return -1;
2800                }
2801                free(new_path);
2802                mfi.clean = 0;
2803        } else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
2804                return -1;
2805        return mfi.clean;
2806}
2807
2808static int conflict_rename_normal(struct merge_options *o,
2809                                  const char *path,
2810                                  struct object_id *o_oid, unsigned int o_mode,
2811                                  struct object_id *a_oid, unsigned int a_mode,
2812                                  struct object_id *b_oid, unsigned int b_mode,
2813                                  struct rename_conflict_info *ci)
2814{
2815        int clean_merge;
2816        int file_in_the_way = 0;
2817
2818        if (was_dirty(o, path)) {
2819                file_in_the_way = 1;
2820                output(o, 1, _("Refusing to lose dirty file at %s"), path);
2821        }
2822
2823        /* Merge the content and write it out */
2824        clean_merge = merge_content(o, path, file_in_the_way,
2825                                    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
2826                                    ci);
2827        if (clean_merge > 0 && file_in_the_way)
2828                clean_merge = 0;
2829        return clean_merge;
2830}
2831
2832/* Per entry merge function */
2833static int process_entry(struct merge_options *o,
2834                         const char *path, struct stage_data *entry)
2835{
2836        int clean_merge = 1;
2837        int normalize = o->renormalize;
2838        unsigned o_mode = entry->stages[1].mode;
2839        unsigned a_mode = entry->stages[2].mode;
2840        unsigned b_mode = entry->stages[3].mode;
2841        struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
2842        struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
2843        struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
2844
2845        entry->processed = 1;
2846        if (entry->rename_conflict_info) {
2847                struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
2848                switch (conflict_info->rename_type) {
2849                case RENAME_NORMAL:
2850                case RENAME_ONE_FILE_TO_ONE:
2851                        clean_merge = conflict_rename_normal(o,
2852                                                             path,
2853                                                             o_oid, o_mode,
2854                                                             a_oid, a_mode,
2855                                                             b_oid, b_mode,
2856                                                             conflict_info);
2857                        break;
2858                case RENAME_DIR:
2859                        clean_merge = 1;
2860                        if (conflict_rename_dir(o,
2861                                                conflict_info->pair1,
2862                                                conflict_info->branch1,
2863                                                conflict_info->branch2))
2864                                clean_merge = -1;
2865                        break;
2866                case RENAME_DELETE:
2867                        clean_merge = 0;
2868                        if (conflict_rename_delete(o,
2869                                                   conflict_info->pair1,
2870                                                   conflict_info->branch1,
2871                                                   conflict_info->branch2))
2872                                clean_merge = -1;
2873                        break;
2874                case RENAME_ONE_FILE_TO_TWO:
2875                        clean_merge = 0;
2876                        if (conflict_rename_rename_1to2(o, conflict_info))
2877                                clean_merge = -1;
2878                        break;
2879                case RENAME_TWO_FILES_TO_ONE:
2880                        clean_merge = 0;
2881                        if (conflict_rename_rename_2to1(o, conflict_info))
2882                                clean_merge = -1;
2883                        break;
2884                default:
2885                        entry->processed = 0;
2886                        break;
2887                }
2888        } else if (o_oid && (!a_oid || !b_oid)) {
2889                /* Case A: Deleted in one */
2890                if ((!a_oid && !b_oid) ||
2891                    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
2892                    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
2893                        /* Deleted in both or deleted in one and
2894                         * unchanged in the other */
2895                        if (a_oid)
2896                                output(o, 2, _("Removing %s"), path);
2897                        /* do not touch working file if it did not exist */
2898                        remove_file(o, 1, path, !a_oid);
2899                } else {
2900                        /* Modify/delete; deleted side may have put a directory in the way */
2901                        clean_merge = 0;
2902                        if (handle_modify_delete(o, path, o_oid, o_mode,
2903                                                 a_oid, a_mode, b_oid, b_mode))
2904                                clean_merge = -1;
2905                }
2906        } else if ((!o_oid && a_oid && !b_oid) ||
2907                   (!o_oid && !a_oid && b_oid)) {
2908                /* Case B: Added in one. */
2909                /* [nothing|directory] -> ([nothing|directory], file) */
2910
2911                const char *add_branch;
2912                const char *other_branch;
2913                unsigned mode;
2914                const struct object_id *oid;
2915                const char *conf;
2916
2917                if (a_oid) {
2918                        add_branch = o->branch1;
2919                        other_branch = o->branch2;
2920                        mode = a_mode;
2921                        oid = a_oid;
2922                        conf = _("file/directory");
2923                } else {
2924                        add_branch = o->branch2;
2925                        other_branch = o->branch1;
2926                        mode = b_mode;
2927                        oid = b_oid;
2928                        conf = _("directory/file");
2929                }
2930                if (dir_in_way(path,
2931                               !o->call_depth && !S_ISGITLINK(a_mode),
2932                               0)) {
2933                        char *new_path = unique_path(o, path, add_branch);
2934                        clean_merge = 0;
2935                        output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
2936                               "Adding %s as %s"),
2937                               conf, path, other_branch, path, new_path);
2938                        if (update_file(o, 0, oid, mode, new_path))
2939                                clean_merge = -1;
2940                        else if (o->call_depth)
2941                                remove_file_from_cache(path);
2942                        free(new_path);
2943                } else {
2944                        output(o, 2, _("Adding %s"), path);
2945                        /* do not overwrite file if already present */
2946                        if (update_file_flags(o, oid, mode, path, 1, !a_oid))
2947                                clean_merge = -1;
2948                }
2949        } else if (a_oid && b_oid) {
2950                /* Case C: Added in both (check for same permissions) and */
2951                /* case D: Modified in both, but differently. */
2952                clean_merge = merge_content(o, path, 0 /* file_in_way */,
2953                                            o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
2954                                            NULL);
2955        } else if (!o_oid && !a_oid && !b_oid) {
2956                /*
2957                 * this entry was deleted altogether. a_mode == 0 means
2958                 * we had that path and want to actively remove it.
2959                 */
2960                remove_file(o, 1, path, !a_mode);
2961        } else
2962                die("BUG: fatal merge failure, shouldn't happen.");
2963
2964        return clean_merge;
2965}
2966
2967int merge_trees(struct merge_options *o,
2968                struct tree *head,
2969                struct tree *merge,
2970                struct tree *common,
2971                struct tree **result)
2972{
2973        int code, clean;
2974
2975        if (o->subtree_shift) {
2976                merge = shift_tree_object(head, merge, o->subtree_shift);
2977                common = shift_tree_object(head, common, o->subtree_shift);
2978        }
2979
2980        if (oid_eq(&common->object.oid, &merge->object.oid)) {
2981                struct strbuf sb = STRBUF_INIT;
2982
2983                if (!o->call_depth && index_has_changes(&sb)) {
2984                        err(o, _("Dirty index: cannot merge (dirty: %s)"),
2985                            sb.buf);
2986                        return 0;
2987                }
2988                output(o, 0, _("Already up to date!"));
2989                *result = head;
2990                return 1;
2991        }
2992
2993        code = git_merge_trees(o, common, head, merge);
2994
2995        if (code != 0) {
2996                if (show(o, 4) || o->call_depth)
2997                        err(o, _("merging of trees %s and %s failed"),
2998                            oid_to_hex(&head->object.oid),
2999                            oid_to_hex(&merge->object.oid));
3000                return -1;
3001        }
3002
3003        if (unmerged_cache()) {
3004                struct string_list *entries;
3005                struct rename_info re_info;
3006                int i;
3007                /*
3008                 * Only need the hashmap while processing entries, so
3009                 * initialize it here and free it when we are done running
3010                 * through the entries. Keeping it in the merge_options as
3011                 * opposed to decaring a local hashmap is for convenience
3012                 * so that we don't have to pass it to around.
3013                 */
3014                hashmap_init(&o->current_file_dir_set, path_hashmap_cmp, NULL, 512);
3015                get_files_dirs(o, head);
3016                get_files_dirs(o, merge);
3017
3018                entries = get_unmerged();
3019                clean = handle_renames(o, common, head, merge, entries,
3020                                       &re_info);
3021                record_df_conflict_files(o, entries);
3022                if (clean < 0)
3023                        goto cleanup;
3024                for (i = entries->nr-1; 0 <= i; i--) {
3025                        const char *path = entries->items[i].string;
3026                        struct stage_data *e = entries->items[i].util;
3027                        if (!e->processed) {
3028                                int ret = process_entry(o, path, e);
3029                                if (!ret)
3030                                        clean = 0;
3031                                else if (ret < 0) {
3032                                        clean = ret;
3033                                        goto cleanup;
3034                                }
3035                        }
3036                }
3037                for (i = 0; i < entries->nr; i++) {
3038                        struct stage_data *e = entries->items[i].util;
3039                        if (!e->processed)
3040                                die("BUG: unprocessed path??? %s",
3041                                    entries->items[i].string);
3042                }
3043
3044cleanup:
3045                final_cleanup_renames(&re_info);
3046
3047                string_list_clear(entries, 1);
3048                free(entries);
3049
3050                hashmap_free(&o->current_file_dir_set, 1);
3051
3052                if (clean < 0)
3053                        return clean;
3054        }
3055        else
3056                clean = 1;
3057
3058        if (o->call_depth && !(*result = write_tree_from_memory(o)))
3059                return -1;
3060
3061        return clean;
3062}
3063
3064static struct commit_list *reverse_commit_list(struct commit_list *list)
3065{
3066        struct commit_list *next = NULL, *current, *backup;
3067        for (current = list; current; current = backup) {
3068                backup = current->next;
3069                current->next = next;
3070                next = current;
3071        }
3072        return next;
3073}
3074
3075/*
3076 * Merge the commits h1 and h2, return the resulting virtual
3077 * commit object and a flag indicating the cleanness of the merge.
3078 */
3079int merge_recursive(struct merge_options *o,
3080                    struct commit *h1,
3081                    struct commit *h2,
3082                    struct commit_list *ca,
3083                    struct commit **result)
3084{
3085        struct commit_list *iter;
3086        struct commit *merged_common_ancestors;
3087        struct tree *mrtree = mrtree;
3088        int clean;
3089
3090        if (show(o, 4)) {
3091                output(o, 4, _("Merging:"));
3092                output_commit_title(o, h1);
3093                output_commit_title(o, h2);
3094        }
3095
3096        if (!ca) {
3097                ca = get_merge_bases(h1, h2);
3098                ca = reverse_commit_list(ca);
3099        }
3100
3101        if (show(o, 5)) {
3102                unsigned cnt = commit_list_count(ca);
3103
3104                output(o, 5, Q_("found %u common ancestor:",
3105                                "found %u common ancestors:", cnt), cnt);
3106                for (iter = ca; iter; iter = iter->next)
3107                        output_commit_title(o, iter->item);
3108        }
3109
3110        merged_common_ancestors = pop_commit(&ca);
3111        if (merged_common_ancestors == NULL) {
3112                /* if there is no common ancestor, use an empty tree */
3113                struct tree *tree;
3114
3115                tree = lookup_tree(the_hash_algo->empty_tree);
3116                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
3117        }
3118
3119        for (iter = ca; iter; iter = iter->next) {
3120                const char *saved_b1, *saved_b2;
3121                o->call_depth++;
3122                /*
3123                 * When the merge fails, the result contains files
3124                 * with conflict markers. The cleanness flag is
3125                 * ignored (unless indicating an error), it was never
3126                 * actually used, as result of merge_trees has always
3127                 * overwritten it: the committed "conflicts" were
3128                 * already resolved.
3129                 */
3130                discard_cache();
3131                saved_b1 = o->branch1;
3132                saved_b2 = o->branch2;
3133                o->branch1 = "Temporary merge branch 1";
3134                o->branch2 = "Temporary merge branch 2";
3135                if (merge_recursive(o, merged_common_ancestors, iter->item,
3136                                    NULL, &merged_common_ancestors) < 0)
3137                        return -1;
3138                o->branch1 = saved_b1;
3139                o->branch2 = saved_b2;
3140                o->call_depth--;
3141
3142                if (!merged_common_ancestors)
3143                        return err(o, _("merge returned no commit"));
3144        }
3145
3146        discard_cache();
3147        if (!o->call_depth)
3148                read_cache();
3149
3150        o->ancestor = "merged common ancestors";
3151        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
3152                            &mrtree);
3153        if (clean < 0) {
3154                flush_output(o);
3155                return clean;
3156        }
3157
3158        if (o->call_depth) {
3159                *result = make_virtual_commit(mrtree, "merged tree");
3160                commit_list_insert(h1, &(*result)->parents);
3161                commit_list_insert(h2, &(*result)->parents->next);
3162        }
3163        flush_output(o);
3164        if (!o->call_depth && o->buffer_output < 2)
3165                strbuf_release(&o->obuf);
3166        if (show(o, 2))
3167                diff_warn_rename_limit("merge.renamelimit",
3168                                       o->needed_rename_limit, 0);
3169        return clean;
3170}
3171
3172static struct commit *get_ref(const struct object_id *oid, const char *name)
3173{
3174        struct object *object;
3175
3176        object = deref_tag(parse_object(oid), name, strlen(name));
3177        if (!object)
3178                return NULL;
3179        if (object->type == OBJ_TREE)
3180                return make_virtual_commit((struct tree*)object, name);
3181        if (object->type != OBJ_COMMIT)
3182                return NULL;
3183        if (parse_commit((struct commit *)object))
3184                return NULL;
3185        return (struct commit *)object;
3186}
3187
3188int merge_recursive_generic(struct merge_options *o,
3189                            const struct object_id *head,
3190                            const struct object_id *merge,
3191                            int num_base_list,
3192                            const struct object_id **base_list,
3193                            struct commit **result)
3194{
3195        int clean;
3196        struct lock_file lock = LOCK_INIT;
3197        struct commit *head_commit = get_ref(head, o->branch1);
3198        struct commit *next_commit = get_ref(merge, o->branch2);
3199        struct commit_list *ca = NULL;
3200
3201        if (base_list) {
3202                int i;
3203                for (i = 0; i < num_base_list; ++i) {
3204                        struct commit *base;
3205                        if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
3206                                return err(o, _("Could not parse object '%s'"),
3207                                        oid_to_hex(base_list[i]));
3208                        commit_list_insert(base, &ca);
3209                }
3210        }
3211
3212        hold_locked_index(&lock, LOCK_DIE_ON_ERROR);
3213        clean = merge_recursive(o, head_commit, next_commit, ca,
3214                        result);
3215        if (clean < 0)
3216                return clean;
3217
3218        if (active_cache_changed &&
3219            write_locked_index(&the_index, &lock, COMMIT_LOCK))
3220                return err(o, _("Unable to write index."));
3221
3222        return clean ? 0 : 1;
3223}
3224
3225static void merge_recursive_config(struct merge_options *o)
3226{
3227        git_config_get_int("merge.verbosity", &o->verbosity);
3228        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
3229        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
3230        git_config(git_xmerge_config, NULL);
3231}
3232
3233void init_merge_options(struct merge_options *o)
3234{
3235        const char *merge_verbosity;
3236        memset(o, 0, sizeof(struct merge_options));
3237        o->verbosity = 2;
3238        o->buffer_output = 1;
3239        o->diff_rename_limit = -1;
3240        o->merge_rename_limit = -1;
3241        o->renormalize = 0;
3242        o->detect_rename = 1;
3243        merge_recursive_config(o);
3244        merge_verbosity = getenv("GIT_MERGE_VERBOSITY");
3245        if (merge_verbosity)
3246                o->verbosity = strtol(merge_verbosity, NULL, 10);
3247        if (o->verbosity >= 5)
3248                o->buffer_output = 0;
3249        strbuf_init(&o->obuf, 0);
3250        string_list_init(&o->df_conflict_file_set, 1);
3251}
3252
3253int parse_merge_opt(struct merge_options *o, const char *s)
3254{
3255        const char *arg;
3256
3257        if (!s || !*s)
3258                return -1;
3259        if (!strcmp(s, "ours"))
3260                o->recursive_variant = MERGE_RECURSIVE_OURS;
3261        else if (!strcmp(s, "theirs"))
3262                o->recursive_variant = MERGE_RECURSIVE_THEIRS;
3263        else if (!strcmp(s, "subtree"))
3264                o->subtree_shift = "";
3265        else if (skip_prefix(s, "subtree=", &arg))
3266                o->subtree_shift = arg;
3267        else if (!strcmp(s, "patience"))
3268                o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
3269        else if (!strcmp(s, "histogram"))
3270                o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
3271        else if (skip_prefix(s, "diff-algorithm=", &arg)) {
3272                long value = parse_algorithm_value(arg);
3273                if (value < 0)
3274                        return -1;
3275                /* clear out previous settings */
3276                DIFF_XDL_CLR(o, NEED_MINIMAL);
3277                o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
3278                o->xdl_opts |= value;
3279        }
3280        else if (!strcmp(s, "ignore-space-change"))
3281                DIFF_XDL_SET(o, IGNORE_WHITESPACE_CHANGE);
3282        else if (!strcmp(s, "ignore-all-space"))
3283                DIFF_XDL_SET(o, IGNORE_WHITESPACE);
3284        else if (!strcmp(s, "ignore-space-at-eol"))
3285                DIFF_XDL_SET(o, IGNORE_WHITESPACE_AT_EOL);
3286        else if (!strcmp(s, "ignore-cr-at-eol"))
3287                DIFF_XDL_SET(o, IGNORE_CR_AT_EOL);
3288        else if (!strcmp(s, "renormalize"))
3289                o->renormalize = 1;
3290        else if (!strcmp(s, "no-renormalize"))
3291                o->renormalize = 0;
3292        else if (!strcmp(s, "no-renames"))
3293                o->detect_rename = 0;
3294        else if (!strcmp(s, "find-renames")) {
3295                o->detect_rename = 1;
3296                o->rename_score = 0;
3297        }
3298        else if (skip_prefix(s, "find-renames=", &arg) ||
3299                 skip_prefix(s, "rename-threshold=", &arg)) {
3300                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
3301                        return -1;
3302                o->detect_rename = 1;
3303        }
3304        else
3305                return -1;
3306        return 0;
3307}