merge-recursive.con commit Merge branch 'bw/forking-and-threading' (7d5e13f)
   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 "advice.h"
   8#include "lockfile.h"
   9#include "cache-tree.h"
  10#include "commit.h"
  11#include "blob.h"
  12#include "builtin.h"
  13#include "tree-walk.h"
  14#include "diff.h"
  15#include "diffcore.h"
  16#include "tag.h"
  17#include "unpack-trees.h"
  18#include "string-list.h"
  19#include "xdiff-interface.h"
  20#include "ll-merge.h"
  21#include "attr.h"
  22#include "merge-recursive.h"
  23#include "dir.h"
  24#include "submodule.h"
  25
  26static void flush_output(struct merge_options *o)
  27{
  28        if (o->buffer_output < 2 && o->obuf.len) {
  29                fputs(o->obuf.buf, stdout);
  30                strbuf_reset(&o->obuf);
  31        }
  32}
  33
  34static int err(struct merge_options *o, const char *err, ...)
  35{
  36        va_list params;
  37
  38        if (o->buffer_output < 2)
  39                flush_output(o);
  40        else {
  41                strbuf_complete(&o->obuf, '\n');
  42                strbuf_addstr(&o->obuf, "error: ");
  43        }
  44        va_start(params, err);
  45        strbuf_vaddf(&o->obuf, err, params);
  46        va_end(params);
  47        if (o->buffer_output > 1)
  48                strbuf_addch(&o->obuf, '\n');
  49        else {
  50                error("%s", o->obuf.buf);
  51                strbuf_reset(&o->obuf);
  52        }
  53
  54        return -1;
  55}
  56
  57static struct tree *shift_tree_object(struct tree *one, struct tree *two,
  58                                      const char *subtree_shift)
  59{
  60        struct object_id shifted;
  61
  62        if (!*subtree_shift) {
  63                shift_tree(&one->object.oid, &two->object.oid, &shifted, 0);
  64        } else {
  65                shift_tree_by(&one->object.oid, &two->object.oid, &shifted,
  66                              subtree_shift);
  67        }
  68        if (!oidcmp(&two->object.oid, &shifted))
  69                return two;
  70        return lookup_tree(&shifted);
  71}
  72
  73static struct commit *make_virtual_commit(struct tree *tree, const char *comment)
  74{
  75        struct commit *commit = alloc_commit_node();
  76
  77        set_merge_remote_desc(commit, comment, (struct object *)commit);
  78        commit->tree = tree;
  79        commit->object.parsed = 1;
  80        return commit;
  81}
  82
  83/*
  84 * Since we use get_tree_entry(), which does not put the read object into
  85 * the object pool, we cannot rely on a == b.
  86 */
  87static int oid_eq(const struct object_id *a, const struct object_id *b)
  88{
  89        if (!a && !b)
  90                return 2;
  91        return a && b && oidcmp(a, b) == 0;
  92}
  93
  94enum rename_type {
  95        RENAME_NORMAL = 0,
  96        RENAME_DELETE,
  97        RENAME_ONE_FILE_TO_ONE,
  98        RENAME_ONE_FILE_TO_TWO,
  99        RENAME_TWO_FILES_TO_ONE
 100};
 101
 102struct rename_conflict_info {
 103        enum rename_type rename_type;
 104        struct diff_filepair *pair1;
 105        struct diff_filepair *pair2;
 106        const char *branch1;
 107        const char *branch2;
 108        struct stage_data *dst_entry1;
 109        struct stage_data *dst_entry2;
 110        struct diff_filespec ren1_other;
 111        struct diff_filespec ren2_other;
 112};
 113
 114/*
 115 * Since we want to write the index eventually, we cannot reuse the index
 116 * for these (temporary) data.
 117 */
 118struct stage_data {
 119        struct {
 120                unsigned mode;
 121                struct object_id oid;
 122        } stages[4];
 123        struct rename_conflict_info *rename_conflict_info;
 124        unsigned processed:1;
 125};
 126
 127static inline void setup_rename_conflict_info(enum rename_type rename_type,
 128                                              struct diff_filepair *pair1,
 129                                              struct diff_filepair *pair2,
 130                                              const char *branch1,
 131                                              const char *branch2,
 132                                              struct stage_data *dst_entry1,
 133                                              struct stage_data *dst_entry2,
 134                                              struct merge_options *o,
 135                                              struct stage_data *src_entry1,
 136                                              struct stage_data *src_entry2)
 137{
 138        struct rename_conflict_info *ci = xcalloc(1, sizeof(struct rename_conflict_info));
 139        ci->rename_type = rename_type;
 140        ci->pair1 = pair1;
 141        ci->branch1 = branch1;
 142        ci->branch2 = branch2;
 143
 144        ci->dst_entry1 = dst_entry1;
 145        dst_entry1->rename_conflict_info = ci;
 146        dst_entry1->processed = 0;
 147
 148        assert(!pair2 == !dst_entry2);
 149        if (dst_entry2) {
 150                ci->dst_entry2 = dst_entry2;
 151                ci->pair2 = pair2;
 152                dst_entry2->rename_conflict_info = ci;
 153        }
 154
 155        if (rename_type == RENAME_TWO_FILES_TO_ONE) {
 156                /*
 157                 * For each rename, there could have been
 158                 * modifications on the side of history where that
 159                 * file was not renamed.
 160                 */
 161                int ostage1 = o->branch1 == branch1 ? 3 : 2;
 162                int ostage2 = ostage1 ^ 1;
 163
 164                ci->ren1_other.path = pair1->one->path;
 165                oidcpy(&ci->ren1_other.oid, &src_entry1->stages[ostage1].oid);
 166                ci->ren1_other.mode = src_entry1->stages[ostage1].mode;
 167
 168                ci->ren2_other.path = pair2->one->path;
 169                oidcpy(&ci->ren2_other.oid, &src_entry2->stages[ostage2].oid);
 170                ci->ren2_other.mode = src_entry2->stages[ostage2].mode;
 171        }
 172}
 173
 174static int show(struct merge_options *o, int v)
 175{
 176        return (!o->call_depth && o->verbosity >= v) || o->verbosity >= 5;
 177}
 178
 179__attribute__((format (printf, 3, 4)))
 180static void output(struct merge_options *o, int v, const char *fmt, ...)
 181{
 182        va_list ap;
 183
 184        if (!show(o, v))
 185                return;
 186
 187        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 188
 189        va_start(ap, fmt);
 190        strbuf_vaddf(&o->obuf, fmt, ap);
 191        va_end(ap);
 192
 193        strbuf_addch(&o->obuf, '\n');
 194        if (!o->buffer_output)
 195                flush_output(o);
 196}
 197
 198static void output_commit_title(struct merge_options *o, struct commit *commit)
 199{
 200        strbuf_addchars(&o->obuf, ' ', o->call_depth * 2);
 201        if (commit->util)
 202                strbuf_addf(&o->obuf, "virtual %s\n",
 203                        merge_remote_util(commit)->name);
 204        else {
 205                strbuf_add_unique_abbrev(&o->obuf, commit->object.oid.hash,
 206                                         DEFAULT_ABBREV);
 207                strbuf_addch(&o->obuf, ' ');
 208                if (parse_commit(commit) != 0)
 209                        strbuf_addstr(&o->obuf, _("(bad commit)\n"));
 210                else {
 211                        const char *title;
 212                        const char *msg = get_commit_buffer(commit, NULL);
 213                        int len = find_commit_subject(msg, &title);
 214                        if (len)
 215                                strbuf_addf(&o->obuf, "%.*s\n", len, title);
 216                        unuse_commit_buffer(commit, msg);
 217                }
 218        }
 219        flush_output(o);
 220}
 221
 222static int add_cacheinfo(struct merge_options *o,
 223                unsigned int mode, const struct object_id *oid,
 224                const char *path, int stage, int refresh, int options)
 225{
 226        struct cache_entry *ce;
 227        int ret;
 228
 229        ce = make_cache_entry(mode, oid ? oid->hash : null_sha1, path, stage, 0);
 230        if (!ce)
 231                return err(o, _("addinfo_cache failed for path '%s'"), path);
 232
 233        ret = add_cache_entry(ce, options);
 234        if (refresh) {
 235                struct cache_entry *nce;
 236
 237                nce = refresh_cache_entry(ce, CE_MATCH_REFRESH | CE_MATCH_IGNORE_MISSING);
 238                if (!nce)
 239                        return err(o, _("addinfo_cache failed for path '%s'"), path);
 240                if (nce != ce)
 241                        ret = add_cache_entry(nce, options);
 242        }
 243        return ret;
 244}
 245
 246static void init_tree_desc_from_tree(struct tree_desc *desc, struct tree *tree)
 247{
 248        parse_tree(tree);
 249        init_tree_desc(desc, tree->buffer, tree->size);
 250}
 251
 252static int git_merge_trees(int index_only,
 253                           struct tree *common,
 254                           struct tree *head,
 255                           struct tree *merge)
 256{
 257        int rc;
 258        struct tree_desc t[3];
 259        struct unpack_trees_options opts;
 260
 261        memset(&opts, 0, sizeof(opts));
 262        if (index_only)
 263                opts.index_only = 1;
 264        else
 265                opts.update = 1;
 266        opts.merge = 1;
 267        opts.head_idx = 2;
 268        opts.fn = threeway_merge;
 269        opts.src_index = &the_index;
 270        opts.dst_index = &the_index;
 271        setup_unpack_trees_porcelain(&opts, "merge");
 272
 273        init_tree_desc_from_tree(t+0, common);
 274        init_tree_desc_from_tree(t+1, head);
 275        init_tree_desc_from_tree(t+2, merge);
 276
 277        rc = unpack_trees(3, t, &opts);
 278        cache_tree_free(&active_cache_tree);
 279        return rc;
 280}
 281
 282struct tree *write_tree_from_memory(struct merge_options *o)
 283{
 284        struct tree *result = NULL;
 285
 286        if (unmerged_cache()) {
 287                int i;
 288                fprintf(stderr, "BUG: There are unmerged index entries:\n");
 289                for (i = 0; i < active_nr; i++) {
 290                        const struct cache_entry *ce = active_cache[i];
 291                        if (ce_stage(ce))
 292                                fprintf(stderr, "BUG: %d %.*s\n", ce_stage(ce),
 293                                        (int)ce_namelen(ce), ce->name);
 294                }
 295                die("BUG: unmerged index entries in merge-recursive.c");
 296        }
 297
 298        if (!active_cache_tree)
 299                active_cache_tree = cache_tree();
 300
 301        if (!cache_tree_fully_valid(active_cache_tree) &&
 302            cache_tree_update(&the_index, 0) < 0) {
 303                err(o, _("error building trees"));
 304                return NULL;
 305        }
 306
 307        result = lookup_tree(&active_cache_tree->oid);
 308
 309        return result;
 310}
 311
 312static int save_files_dirs(const unsigned char *sha1,
 313                struct strbuf *base, const char *path,
 314                unsigned int mode, int stage, void *context)
 315{
 316        int baselen = base->len;
 317        struct merge_options *o = context;
 318
 319        strbuf_addstr(base, path);
 320
 321        if (S_ISDIR(mode))
 322                string_list_insert(&o->current_directory_set, base->buf);
 323        else
 324                string_list_insert(&o->current_file_set, base->buf);
 325
 326        strbuf_setlen(base, baselen);
 327        return (S_ISDIR(mode) ? READ_TREE_RECURSIVE : 0);
 328}
 329
 330static int get_files_dirs(struct merge_options *o, struct tree *tree)
 331{
 332        int n;
 333        struct pathspec match_all;
 334        memset(&match_all, 0, sizeof(match_all));
 335        if (read_tree_recursive(tree, "", 0, 0, &match_all, save_files_dirs, o))
 336                return 0;
 337        n = o->current_file_set.nr + o->current_directory_set.nr;
 338        return n;
 339}
 340
 341/*
 342 * Returns an index_entry instance which doesn't have to correspond to
 343 * a real cache entry in Git's index.
 344 */
 345static struct stage_data *insert_stage_data(const char *path,
 346                struct tree *o, struct tree *a, struct tree *b,
 347                struct string_list *entries)
 348{
 349        struct string_list_item *item;
 350        struct stage_data *e = xcalloc(1, sizeof(struct stage_data));
 351        get_tree_entry(o->object.oid.hash, path,
 352                        e->stages[1].oid.hash, &e->stages[1].mode);
 353        get_tree_entry(a->object.oid.hash, path,
 354                        e->stages[2].oid.hash, &e->stages[2].mode);
 355        get_tree_entry(b->object.oid.hash, path,
 356                        e->stages[3].oid.hash, &e->stages[3].mode);
 357        item = string_list_insert(entries, path);
 358        item->util = e;
 359        return e;
 360}
 361
 362/*
 363 * Create a dictionary mapping file names to stage_data objects. The
 364 * dictionary contains one entry for every path with a non-zero stage entry.
 365 */
 366static struct string_list *get_unmerged(void)
 367{
 368        struct string_list *unmerged = xcalloc(1, sizeof(struct string_list));
 369        int i;
 370
 371        unmerged->strdup_strings = 1;
 372
 373        for (i = 0; i < active_nr; i++) {
 374                struct string_list_item *item;
 375                struct stage_data *e;
 376                const struct cache_entry *ce = active_cache[i];
 377                if (!ce_stage(ce))
 378                        continue;
 379
 380                item = string_list_lookup(unmerged, ce->name);
 381                if (!item) {
 382                        item = string_list_insert(unmerged, ce->name);
 383                        item->util = xcalloc(1, sizeof(struct stage_data));
 384                }
 385                e = item->util;
 386                e->stages[ce_stage(ce)].mode = ce->ce_mode;
 387                oidcpy(&e->stages[ce_stage(ce)].oid, &ce->oid);
 388        }
 389
 390        return unmerged;
 391}
 392
 393static int string_list_df_name_compare(const char *one, const char *two)
 394{
 395        int onelen = strlen(one);
 396        int twolen = strlen(two);
 397        /*
 398         * Here we only care that entries for D/F conflicts are
 399         * adjacent, in particular with the file of the D/F conflict
 400         * appearing before files below the corresponding directory.
 401         * The order of the rest of the list is irrelevant for us.
 402         *
 403         * To achieve this, we sort with df_name_compare and provide
 404         * the mode S_IFDIR so that D/F conflicts will sort correctly.
 405         * We use the mode S_IFDIR for everything else for simplicity,
 406         * since in other cases any changes in their order due to
 407         * sorting cause no problems for us.
 408         */
 409        int cmp = df_name_compare(one, onelen, S_IFDIR,
 410                                  two, twolen, S_IFDIR);
 411        /*
 412         * Now that 'foo' and 'foo/bar' compare equal, we have to make sure
 413         * that 'foo' comes before 'foo/bar'.
 414         */
 415        if (cmp)
 416                return cmp;
 417        return onelen - twolen;
 418}
 419
 420static void record_df_conflict_files(struct merge_options *o,
 421                                     struct string_list *entries)
 422{
 423        /* If there is a D/F conflict and the file for such a conflict
 424         * currently exist in the working tree, we want to allow it to be
 425         * removed to make room for the corresponding directory if needed.
 426         * The files underneath the directories of such D/F conflicts will
 427         * be processed before the corresponding file involved in the D/F
 428         * conflict.  If the D/F directory ends up being removed by the
 429         * merge, then we won't have to touch the D/F file.  If the D/F
 430         * directory needs to be written to the working copy, then the D/F
 431         * file will simply be removed (in make_room_for_path()) to make
 432         * room for the necessary paths.  Note that if both the directory
 433         * and the file need to be present, then the D/F file will be
 434         * reinstated with a new unique name at the time it is processed.
 435         */
 436        struct string_list df_sorted_entries = STRING_LIST_INIT_NODUP;
 437        const char *last_file = NULL;
 438        int last_len = 0;
 439        int i;
 440
 441        /*
 442         * If we're merging merge-bases, we don't want to bother with
 443         * any working directory changes.
 444         */
 445        if (o->call_depth)
 446                return;
 447
 448        /* Ensure D/F conflicts are adjacent in the entries list. */
 449        for (i = 0; i < entries->nr; i++) {
 450                struct string_list_item *next = &entries->items[i];
 451                string_list_append(&df_sorted_entries, next->string)->util =
 452                                   next->util;
 453        }
 454        df_sorted_entries.cmp = string_list_df_name_compare;
 455        string_list_sort(&df_sorted_entries);
 456
 457        string_list_clear(&o->df_conflict_file_set, 1);
 458        for (i = 0; i < df_sorted_entries.nr; i++) {
 459                const char *path = df_sorted_entries.items[i].string;
 460                int len = strlen(path);
 461                struct stage_data *e = df_sorted_entries.items[i].util;
 462
 463                /*
 464                 * Check if last_file & path correspond to a D/F conflict;
 465                 * i.e. whether path is last_file+'/'+<something>.
 466                 * If so, record that it's okay to remove last_file to make
 467                 * room for path and friends if needed.
 468                 */
 469                if (last_file &&
 470                    len > last_len &&
 471                    memcmp(path, last_file, last_len) == 0 &&
 472                    path[last_len] == '/') {
 473                        string_list_insert(&o->df_conflict_file_set, last_file);
 474                }
 475
 476                /*
 477                 * Determine whether path could exist as a file in the
 478                 * working directory as a possible D/F conflict.  This
 479                 * will only occur when it exists in stage 2 as a
 480                 * file.
 481                 */
 482                if (S_ISREG(e->stages[2].mode) || S_ISLNK(e->stages[2].mode)) {
 483                        last_file = path;
 484                        last_len = len;
 485                } else {
 486                        last_file = NULL;
 487                }
 488        }
 489        string_list_clear(&df_sorted_entries, 0);
 490}
 491
 492struct rename {
 493        struct diff_filepair *pair;
 494        struct stage_data *src_entry;
 495        struct stage_data *dst_entry;
 496        unsigned processed:1;
 497};
 498
 499/*
 500 * Get information of all renames which occurred between 'o_tree' and
 501 * 'tree'. We need the three trees in the merge ('o_tree', 'a_tree' and
 502 * 'b_tree') to be able to associate the correct cache entries with
 503 * the rename information. 'tree' is always equal to either a_tree or b_tree.
 504 */
 505static struct string_list *get_renames(struct merge_options *o,
 506                                       struct tree *tree,
 507                                       struct tree *o_tree,
 508                                       struct tree *a_tree,
 509                                       struct tree *b_tree,
 510                                       struct string_list *entries)
 511{
 512        int i;
 513        struct string_list *renames;
 514        struct diff_options opts;
 515
 516        renames = xcalloc(1, sizeof(struct string_list));
 517        if (!o->detect_rename)
 518                return renames;
 519
 520        diff_setup(&opts);
 521        DIFF_OPT_SET(&opts, RECURSIVE);
 522        DIFF_OPT_CLR(&opts, RENAME_EMPTY);
 523        opts.detect_rename = DIFF_DETECT_RENAME;
 524        opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
 525                            o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 526                            1000;
 527        opts.rename_score = o->rename_score;
 528        opts.show_rename_progress = o->show_rename_progress;
 529        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 530        diff_setup_done(&opts);
 531        diff_tree_sha1(o_tree->object.oid.hash, tree->object.oid.hash, "", &opts);
 532        diffcore_std(&opts);
 533        if (opts.needed_rename_limit > o->needed_rename_limit)
 534                o->needed_rename_limit = opts.needed_rename_limit;
 535        for (i = 0; i < diff_queued_diff.nr; ++i) {
 536                struct string_list_item *item;
 537                struct rename *re;
 538                struct diff_filepair *pair = diff_queued_diff.queue[i];
 539                if (pair->status != 'R') {
 540                        diff_free_filepair(pair);
 541                        continue;
 542                }
 543                re = xmalloc(sizeof(*re));
 544                re->processed = 0;
 545                re->pair = pair;
 546                item = string_list_lookup(entries, re->pair->one->path);
 547                if (!item)
 548                        re->src_entry = insert_stage_data(re->pair->one->path,
 549                                        o_tree, a_tree, b_tree, entries);
 550                else
 551                        re->src_entry = item->util;
 552
 553                item = string_list_lookup(entries, re->pair->two->path);
 554                if (!item)
 555                        re->dst_entry = insert_stage_data(re->pair->two->path,
 556                                        o_tree, a_tree, b_tree, entries);
 557                else
 558                        re->dst_entry = item->util;
 559                item = string_list_insert(renames, pair->one->path);
 560                item->util = re;
 561        }
 562        opts.output_format = DIFF_FORMAT_NO_OUTPUT;
 563        diff_queued_diff.nr = 0;
 564        diff_flush(&opts);
 565        return renames;
 566}
 567
 568static int update_stages(struct merge_options *opt, const char *path,
 569                         const struct diff_filespec *o,
 570                         const struct diff_filespec *a,
 571                         const struct diff_filespec *b)
 572{
 573
 574        /*
 575         * NOTE: It is usually a bad idea to call update_stages on a path
 576         * before calling update_file on that same path, since it can
 577         * sometimes lead to spurious "refusing to lose untracked file..."
 578         * messages from update_file (via make_room_for path via
 579         * would_lose_untracked).  Instead, reverse the order of the calls
 580         * (executing update_file first and then update_stages).
 581         */
 582        int clear = 1;
 583        int options = ADD_CACHE_OK_TO_ADD | ADD_CACHE_SKIP_DFCHECK;
 584        if (clear)
 585                if (remove_file_from_cache(path))
 586                        return -1;
 587        if (o)
 588                if (add_cacheinfo(opt, o->mode, &o->oid, path, 1, 0, options))
 589                        return -1;
 590        if (a)
 591                if (add_cacheinfo(opt, a->mode, &a->oid, path, 2, 0, options))
 592                        return -1;
 593        if (b)
 594                if (add_cacheinfo(opt, b->mode, &b->oid, path, 3, 0, options))
 595                        return -1;
 596        return 0;
 597}
 598
 599static void update_entry(struct stage_data *entry,
 600                         struct diff_filespec *o,
 601                         struct diff_filespec *a,
 602                         struct diff_filespec *b)
 603{
 604        entry->processed = 0;
 605        entry->stages[1].mode = o->mode;
 606        entry->stages[2].mode = a->mode;
 607        entry->stages[3].mode = b->mode;
 608        oidcpy(&entry->stages[1].oid, &o->oid);
 609        oidcpy(&entry->stages[2].oid, &a->oid);
 610        oidcpy(&entry->stages[3].oid, &b->oid);
 611}
 612
 613static int remove_file(struct merge_options *o, int clean,
 614                       const char *path, int no_wd)
 615{
 616        int update_cache = o->call_depth || clean;
 617        int update_working_directory = !o->call_depth && !no_wd;
 618
 619        if (update_cache) {
 620                if (remove_file_from_cache(path))
 621                        return -1;
 622        }
 623        if (update_working_directory) {
 624                if (ignore_case) {
 625                        struct cache_entry *ce;
 626                        ce = cache_file_exists(path, strlen(path), ignore_case);
 627                        if (ce && ce_stage(ce) == 0)
 628                                return 0;
 629                }
 630                if (remove_path(path))
 631                        return -1;
 632        }
 633        return 0;
 634}
 635
 636/* add a string to a strbuf, but converting "/" to "_" */
 637static void add_flattened_path(struct strbuf *out, const char *s)
 638{
 639        size_t i = out->len;
 640        strbuf_addstr(out, s);
 641        for (; i < out->len; i++)
 642                if (out->buf[i] == '/')
 643                        out->buf[i] = '_';
 644}
 645
 646static char *unique_path(struct merge_options *o, const char *path, const char *branch)
 647{
 648        struct strbuf newpath = STRBUF_INIT;
 649        int suffix = 0;
 650        size_t base_len;
 651
 652        strbuf_addf(&newpath, "%s~", path);
 653        add_flattened_path(&newpath, branch);
 654
 655        base_len = newpath.len;
 656        while (string_list_has_string(&o->current_file_set, newpath.buf) ||
 657               string_list_has_string(&o->current_directory_set, newpath.buf) ||
 658               (!o->call_depth && file_exists(newpath.buf))) {
 659                strbuf_setlen(&newpath, base_len);
 660                strbuf_addf(&newpath, "_%d", suffix++);
 661        }
 662
 663        string_list_insert(&o->current_file_set, newpath.buf);
 664        return strbuf_detach(&newpath, NULL);
 665}
 666
 667/**
 668 * Check whether a directory in the index is in the way of an incoming
 669 * file.  Return 1 if so.  If check_working_copy is non-zero, also
 670 * check the working directory.  If empty_ok is non-zero, also return
 671 * 0 in the case where the working-tree dir exists but is empty.
 672 */
 673static int dir_in_way(const char *path, int check_working_copy, int empty_ok)
 674{
 675        int pos;
 676        struct strbuf dirpath = STRBUF_INIT;
 677        struct stat st;
 678
 679        strbuf_addstr(&dirpath, path);
 680        strbuf_addch(&dirpath, '/');
 681
 682        pos = cache_name_pos(dirpath.buf, dirpath.len);
 683
 684        if (pos < 0)
 685                pos = -1 - pos;
 686        if (pos < active_nr &&
 687            !strncmp(dirpath.buf, active_cache[pos]->name, dirpath.len)) {
 688                strbuf_release(&dirpath);
 689                return 1;
 690        }
 691
 692        strbuf_release(&dirpath);
 693        return check_working_copy && !lstat(path, &st) && S_ISDIR(st.st_mode) &&
 694                !(empty_ok && is_empty_dir(path));
 695}
 696
 697static int was_tracked(const char *path)
 698{
 699        int pos = cache_name_pos(path, strlen(path));
 700
 701        if (0 <= pos)
 702                /* we have been tracking this path */
 703                return 1;
 704
 705        /*
 706         * Look for an unmerged entry for the path,
 707         * specifically stage #2, which would indicate
 708         * that "our" side before the merge started
 709         * had the path tracked (and resulted in a conflict).
 710         */
 711        for (pos = -1 - pos;
 712             pos < active_nr && !strcmp(path, active_cache[pos]->name);
 713             pos++)
 714                if (ce_stage(active_cache[pos]) == 2)
 715                        return 1;
 716        return 0;
 717}
 718
 719static int would_lose_untracked(const char *path)
 720{
 721        return !was_tracked(path) && file_exists(path);
 722}
 723
 724static int make_room_for_path(struct merge_options *o, const char *path)
 725{
 726        int status, i;
 727        const char *msg = _("failed to create path '%s'%s");
 728
 729        /* Unlink any D/F conflict files that are in the way */
 730        for (i = 0; i < o->df_conflict_file_set.nr; i++) {
 731                const char *df_path = o->df_conflict_file_set.items[i].string;
 732                size_t pathlen = strlen(path);
 733                size_t df_pathlen = strlen(df_path);
 734                if (df_pathlen < pathlen &&
 735                    path[df_pathlen] == '/' &&
 736                    strncmp(path, df_path, df_pathlen) == 0) {
 737                        output(o, 3,
 738                               _("Removing %s to make room for subdirectory\n"),
 739                               df_path);
 740                        unlink(df_path);
 741                        unsorted_string_list_delete_item(&o->df_conflict_file_set,
 742                                                         i, 0);
 743                        break;
 744                }
 745        }
 746
 747        /* Make sure leading directories are created */
 748        status = safe_create_leading_directories_const(path);
 749        if (status) {
 750                if (status == SCLD_EXISTS)
 751                        /* something else exists */
 752                        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 753                return err(o, msg, path, "");
 754        }
 755
 756        /*
 757         * Do not unlink a file in the work tree if we are not
 758         * tracking it.
 759         */
 760        if (would_lose_untracked(path))
 761                return err(o, _("refusing to lose untracked file at '%s'"),
 762                             path);
 763
 764        /* Successful unlink is good.. */
 765        if (!unlink(path))
 766                return 0;
 767        /* .. and so is no existing file */
 768        if (errno == ENOENT)
 769                return 0;
 770        /* .. but not some other error (who really cares what?) */
 771        return err(o, msg, path, _(": perhaps a D/F conflict?"));
 772}
 773
 774static int update_file_flags(struct merge_options *o,
 775                             const struct object_id *oid,
 776                             unsigned mode,
 777                             const char *path,
 778                             int update_cache,
 779                             int update_wd)
 780{
 781        int ret = 0;
 782
 783        if (o->call_depth)
 784                update_wd = 0;
 785
 786        if (update_wd) {
 787                enum object_type type;
 788                void *buf;
 789                unsigned long size;
 790
 791                if (S_ISGITLINK(mode)) {
 792                        /*
 793                         * We may later decide to recursively descend into
 794                         * the submodule directory and update its index
 795                         * and/or work tree, but we do not do that now.
 796                         */
 797                        update_wd = 0;
 798                        goto update_index;
 799                }
 800
 801                buf = read_sha1_file(oid->hash, &type, &size);
 802                if (!buf)
 803                        return err(o, _("cannot read object %s '%s'"), oid_to_hex(oid), path);
 804                if (type != OBJ_BLOB) {
 805                        ret = err(o, _("blob expected for %s '%s'"), oid_to_hex(oid), path);
 806                        goto free_buf;
 807                }
 808                if (S_ISREG(mode)) {
 809                        struct strbuf strbuf = STRBUF_INIT;
 810                        if (convert_to_working_tree(path, buf, size, &strbuf)) {
 811                                free(buf);
 812                                size = strbuf.len;
 813                                buf = strbuf_detach(&strbuf, NULL);
 814                        }
 815                }
 816
 817                if (make_room_for_path(o, path) < 0) {
 818                        update_wd = 0;
 819                        goto free_buf;
 820                }
 821                if (S_ISREG(mode) || (!has_symlinks && S_ISLNK(mode))) {
 822                        int fd;
 823                        if (mode & 0100)
 824                                mode = 0777;
 825                        else
 826                                mode = 0666;
 827                        fd = open(path, O_WRONLY | O_TRUNC | O_CREAT, mode);
 828                        if (fd < 0) {
 829                                ret = err(o, _("failed to open '%s': %s"),
 830                                          path, strerror(errno));
 831                                goto free_buf;
 832                        }
 833                        write_in_full(fd, buf, size);
 834                        close(fd);
 835                } else if (S_ISLNK(mode)) {
 836                        char *lnk = xmemdupz(buf, size);
 837                        safe_create_leading_directories_const(path);
 838                        unlink(path);
 839                        if (symlink(lnk, path))
 840                                ret = err(o, _("failed to symlink '%s': %s"),
 841                                        path, strerror(errno));
 842                        free(lnk);
 843                } else
 844                        ret = err(o,
 845                                  _("do not know what to do with %06o %s '%s'"),
 846                                  mode, oid_to_hex(oid), path);
 847 free_buf:
 848                free(buf);
 849        }
 850 update_index:
 851        if (!ret && update_cache)
 852                add_cacheinfo(o, mode, oid, path, 0, update_wd, ADD_CACHE_OK_TO_ADD);
 853        return ret;
 854}
 855
 856static int update_file(struct merge_options *o,
 857                       int clean,
 858                       const struct object_id *oid,
 859                       unsigned mode,
 860                       const char *path)
 861{
 862        return update_file_flags(o, oid, mode, path, o->call_depth || clean, !o->call_depth);
 863}
 864
 865/* Low level file merging, update and removal */
 866
 867struct merge_file_info {
 868        struct object_id oid;
 869        unsigned mode;
 870        unsigned clean:1,
 871                 merge:1;
 872};
 873
 874static int merge_3way(struct merge_options *o,
 875                      mmbuffer_t *result_buf,
 876                      const struct diff_filespec *one,
 877                      const struct diff_filespec *a,
 878                      const struct diff_filespec *b,
 879                      const char *branch1,
 880                      const char *branch2)
 881{
 882        mmfile_t orig, src1, src2;
 883        struct ll_merge_options ll_opts = {0};
 884        char *base_name, *name1, *name2;
 885        int merge_status;
 886
 887        ll_opts.renormalize = o->renormalize;
 888        ll_opts.xdl_opts = o->xdl_opts;
 889
 890        if (o->call_depth) {
 891                ll_opts.virtual_ancestor = 1;
 892                ll_opts.variant = 0;
 893        } else {
 894                switch (o->recursive_variant) {
 895                case MERGE_RECURSIVE_OURS:
 896                        ll_opts.variant = XDL_MERGE_FAVOR_OURS;
 897                        break;
 898                case MERGE_RECURSIVE_THEIRS:
 899                        ll_opts.variant = XDL_MERGE_FAVOR_THEIRS;
 900                        break;
 901                default:
 902                        ll_opts.variant = 0;
 903                        break;
 904                }
 905        }
 906
 907        if (strcmp(a->path, b->path) ||
 908            (o->ancestor != NULL && strcmp(a->path, one->path) != 0)) {
 909                base_name = o->ancestor == NULL ? NULL :
 910                        mkpathdup("%s:%s", o->ancestor, one->path);
 911                name1 = mkpathdup("%s:%s", branch1, a->path);
 912                name2 = mkpathdup("%s:%s", branch2, b->path);
 913        } else {
 914                base_name = o->ancestor == NULL ? NULL :
 915                        mkpathdup("%s", o->ancestor);
 916                name1 = mkpathdup("%s", branch1);
 917                name2 = mkpathdup("%s", branch2);
 918        }
 919
 920        read_mmblob(&orig, &one->oid);
 921        read_mmblob(&src1, &a->oid);
 922        read_mmblob(&src2, &b->oid);
 923
 924        merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 925                                &src1, name1, &src2, name2, &ll_opts);
 926
 927        free(base_name);
 928        free(name1);
 929        free(name2);
 930        free(orig.ptr);
 931        free(src1.ptr);
 932        free(src2.ptr);
 933        return merge_status;
 934}
 935
 936static int merge_file_1(struct merge_options *o,
 937                                           const struct diff_filespec *one,
 938                                           const struct diff_filespec *a,
 939                                           const struct diff_filespec *b,
 940                                           const char *branch1,
 941                                           const char *branch2,
 942                                           struct merge_file_info *result)
 943{
 944        result->merge = 0;
 945        result->clean = 1;
 946
 947        if ((S_IFMT & a->mode) != (S_IFMT & b->mode)) {
 948                result->clean = 0;
 949                if (S_ISREG(a->mode)) {
 950                        result->mode = a->mode;
 951                        oidcpy(&result->oid, &a->oid);
 952                } else {
 953                        result->mode = b->mode;
 954                        oidcpy(&result->oid, &b->oid);
 955                }
 956        } else {
 957                if (!oid_eq(&a->oid, &one->oid) && !oid_eq(&b->oid, &one->oid))
 958                        result->merge = 1;
 959
 960                /*
 961                 * Merge modes
 962                 */
 963                if (a->mode == b->mode || a->mode == one->mode)
 964                        result->mode = b->mode;
 965                else {
 966                        result->mode = a->mode;
 967                        if (b->mode != one->mode) {
 968                                result->clean = 0;
 969                                result->merge = 1;
 970                        }
 971                }
 972
 973                if (oid_eq(&a->oid, &b->oid) || oid_eq(&a->oid, &one->oid))
 974                        oidcpy(&result->oid, &b->oid);
 975                else if (oid_eq(&b->oid, &one->oid))
 976                        oidcpy(&result->oid, &a->oid);
 977                else if (S_ISREG(a->mode)) {
 978                        mmbuffer_t result_buf;
 979                        int ret = 0, merge_status;
 980
 981                        merge_status = merge_3way(o, &result_buf, one, a, b,
 982                                                  branch1, branch2);
 983
 984                        if ((merge_status < 0) || !result_buf.ptr)
 985                                ret = err(o, _("Failed to execute internal merge"));
 986
 987                        if (!ret && write_sha1_file(result_buf.ptr, result_buf.size,
 988                                                    blob_type, result->oid.hash))
 989                                ret = err(o, _("Unable to add %s to database"),
 990                                          a->path);
 991
 992                        free(result_buf.ptr);
 993                        if (ret)
 994                                return ret;
 995                        result->clean = (merge_status == 0);
 996                } else if (S_ISGITLINK(a->mode)) {
 997                        result->clean = merge_submodule(&result->oid,
 998                                                       one->path,
 999                                                       &one->oid,
1000                                                       &a->oid,
1001                                                       &b->oid,
1002                                                       !o->call_depth);
1003                } else if (S_ISLNK(a->mode)) {
1004                        oidcpy(&result->oid, &a->oid);
1005
1006                        if (!oid_eq(&a->oid, &b->oid))
1007                                result->clean = 0;
1008                } else
1009                        die("BUG: unsupported object type in the tree");
1010        }
1011
1012        return 0;
1013}
1014
1015static int merge_file_special_markers(struct merge_options *o,
1016                           const struct diff_filespec *one,
1017                           const struct diff_filespec *a,
1018                           const struct diff_filespec *b,
1019                           const char *branch1,
1020                           const char *filename1,
1021                           const char *branch2,
1022                           const char *filename2,
1023                           struct merge_file_info *mfi)
1024{
1025        char *side1 = NULL;
1026        char *side2 = NULL;
1027        int ret;
1028
1029        if (filename1)
1030                side1 = xstrfmt("%s:%s", branch1, filename1);
1031        if (filename2)
1032                side2 = xstrfmt("%s:%s", branch2, filename2);
1033
1034        ret = merge_file_1(o, one, a, b,
1035                           side1 ? side1 : branch1,
1036                           side2 ? side2 : branch2, mfi);
1037        free(side1);
1038        free(side2);
1039        return ret;
1040}
1041
1042static int merge_file_one(struct merge_options *o,
1043                                         const char *path,
1044                                         const struct object_id *o_oid, int o_mode,
1045                                         const struct object_id *a_oid, int a_mode,
1046                                         const struct object_id *b_oid, int b_mode,
1047                                         const char *branch1,
1048                                         const char *branch2,
1049                                         struct merge_file_info *mfi)
1050{
1051        struct diff_filespec one, a, b;
1052
1053        one.path = a.path = b.path = (char *)path;
1054        oidcpy(&one.oid, o_oid);
1055        one.mode = o_mode;
1056        oidcpy(&a.oid, a_oid);
1057        a.mode = a_mode;
1058        oidcpy(&b.oid, b_oid);
1059        b.mode = b_mode;
1060        return merge_file_1(o, &one, &a, &b, branch1, branch2, mfi);
1061}
1062
1063static int handle_change_delete(struct merge_options *o,
1064                                 const char *path, const char *old_path,
1065                                 const struct object_id *o_oid, int o_mode,
1066                                 const struct object_id *changed_oid,
1067                                 int changed_mode,
1068                                 const char *change_branch,
1069                                 const char *delete_branch,
1070                                 const char *change, const char *change_past)
1071{
1072        char *alt_path = NULL;
1073        const char *update_path = path;
1074        int ret = 0;
1075
1076        if (dir_in_way(path, !o->call_depth, 0)) {
1077                update_path = alt_path = unique_path(o, path, change_branch);
1078        }
1079
1080        if (o->call_depth) {
1081                /*
1082                 * We cannot arbitrarily accept either a_sha or b_sha as
1083                 * correct; since there is no true "middle point" between
1084                 * them, simply reuse the base version for virtual merge base.
1085                 */
1086                ret = remove_file_from_cache(path);
1087                if (!ret)
1088                        ret = update_file(o, 0, o_oid, o_mode, update_path);
1089        } else {
1090                if (!alt_path) {
1091                        if (!old_path) {
1092                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1093                                       "and %s in %s. Version %s of %s left in tree."),
1094                                       change, path, delete_branch, change_past,
1095                                       change_branch, change_branch, path);
1096                        } else {
1097                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1098                                       "and %s to %s in %s. Version %s of %s left in tree."),
1099                                       change, old_path, delete_branch, change_past, path,
1100                                       change_branch, change_branch, path);
1101                        }
1102                } else {
1103                        if (!old_path) {
1104                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1105                                       "and %s in %s. Version %s of %s left in tree at %s."),
1106                                       change, path, delete_branch, change_past,
1107                                       change_branch, change_branch, path, alt_path);
1108                        } else {
1109                                output(o, 1, _("CONFLICT (%s/delete): %s deleted in %s "
1110                                       "and %s to %s in %s. Version %s of %s left in tree at %s."),
1111                                       change, old_path, delete_branch, change_past, path,
1112                                       change_branch, change_branch, path, alt_path);
1113                        }
1114                }
1115                /*
1116                 * No need to call update_file() on path when change_branch ==
1117                 * o->branch1 && !alt_path, since that would needlessly touch
1118                 * path.  We could call update_file_flags() with update_cache=0
1119                 * and update_wd=0, but that's a no-op.
1120                 */
1121                if (change_branch != o->branch1 || alt_path)
1122                        ret = update_file(o, 0, changed_oid, changed_mode, update_path);
1123        }
1124        free(alt_path);
1125
1126        return ret;
1127}
1128
1129static int conflict_rename_delete(struct merge_options *o,
1130                                   struct diff_filepair *pair,
1131                                   const char *rename_branch,
1132                                   const char *delete_branch)
1133{
1134        const struct diff_filespec *orig = pair->one;
1135        const struct diff_filespec *dest = pair->two;
1136
1137        if (handle_change_delete(o,
1138                                 o->call_depth ? orig->path : dest->path,
1139                                 o->call_depth ? NULL : orig->path,
1140                                 &orig->oid, orig->mode,
1141                                 &dest->oid, dest->mode,
1142                                 rename_branch, delete_branch,
1143                                 _("rename"), _("renamed")))
1144                return -1;
1145
1146        if (o->call_depth)
1147                return remove_file_from_cache(dest->path);
1148        else
1149                return update_stages(o, dest->path, NULL,
1150                                     rename_branch == o->branch1 ? dest : NULL,
1151                                     rename_branch == o->branch1 ? NULL : dest);
1152}
1153
1154static struct diff_filespec *filespec_from_entry(struct diff_filespec *target,
1155                                                 struct stage_data *entry,
1156                                                 int stage)
1157{
1158        struct object_id *oid = &entry->stages[stage].oid;
1159        unsigned mode = entry->stages[stage].mode;
1160        if (mode == 0 || is_null_oid(oid))
1161                return NULL;
1162        oidcpy(&target->oid, oid);
1163        target->mode = mode;
1164        return target;
1165}
1166
1167static int handle_file(struct merge_options *o,
1168                        struct diff_filespec *rename,
1169                        int stage,
1170                        struct rename_conflict_info *ci)
1171{
1172        char *dst_name = rename->path;
1173        struct stage_data *dst_entry;
1174        const char *cur_branch, *other_branch;
1175        struct diff_filespec other;
1176        struct diff_filespec *add;
1177        int ret;
1178
1179        if (stage == 2) {
1180                dst_entry = ci->dst_entry1;
1181                cur_branch = ci->branch1;
1182                other_branch = ci->branch2;
1183        } else {
1184                dst_entry = ci->dst_entry2;
1185                cur_branch = ci->branch2;
1186                other_branch = ci->branch1;
1187        }
1188
1189        add = filespec_from_entry(&other, dst_entry, stage ^ 1);
1190        if (add) {
1191                char *add_name = unique_path(o, rename->path, other_branch);
1192                if (update_file(o, 0, &add->oid, add->mode, add_name))
1193                        return -1;
1194
1195                remove_file(o, 0, rename->path, 0);
1196                dst_name = unique_path(o, rename->path, cur_branch);
1197        } else {
1198                if (dir_in_way(rename->path, !o->call_depth, 0)) {
1199                        dst_name = unique_path(o, rename->path, cur_branch);
1200                        output(o, 1, _("%s is a directory in %s adding as %s instead"),
1201                               rename->path, other_branch, dst_name);
1202                }
1203        }
1204        if ((ret = update_file(o, 0, &rename->oid, rename->mode, dst_name)))
1205                ; /* fall through, do allow dst_name to be released */
1206        else if (stage == 2)
1207                ret = update_stages(o, rename->path, NULL, rename, add);
1208        else
1209                ret = update_stages(o, rename->path, NULL, add, rename);
1210
1211        if (dst_name != rename->path)
1212                free(dst_name);
1213
1214        return ret;
1215}
1216
1217static int conflict_rename_rename_1to2(struct merge_options *o,
1218                                        struct rename_conflict_info *ci)
1219{
1220        /* One file was renamed in both branches, but to different names. */
1221        struct diff_filespec *one = ci->pair1->one;
1222        struct diff_filespec *a = ci->pair1->two;
1223        struct diff_filespec *b = ci->pair2->two;
1224
1225        output(o, 1, _("CONFLICT (rename/rename): "
1226               "Rename \"%s\"->\"%s\" in branch \"%s\" "
1227               "rename \"%s\"->\"%s\" in \"%s\"%s"),
1228               one->path, a->path, ci->branch1,
1229               one->path, b->path, ci->branch2,
1230               o->call_depth ? _(" (left unresolved)") : "");
1231        if (o->call_depth) {
1232                struct merge_file_info mfi;
1233                struct diff_filespec other;
1234                struct diff_filespec *add;
1235                if (merge_file_one(o, one->path,
1236                                 &one->oid, one->mode,
1237                                 &a->oid, a->mode,
1238                                 &b->oid, b->mode,
1239                                 ci->branch1, ci->branch2, &mfi))
1240                        return -1;
1241
1242                /*
1243                 * FIXME: For rename/add-source conflicts (if we could detect
1244                 * such), this is wrong.  We should instead find a unique
1245                 * pathname and then either rename the add-source file to that
1246                 * unique path, or use that unique path instead of src here.
1247                 */
1248                if (update_file(o, 0, &mfi.oid, mfi.mode, one->path))
1249                        return -1;
1250
1251                /*
1252                 * Above, we put the merged content at the merge-base's
1253                 * path.  Now we usually need to delete both a->path and
1254                 * b->path.  However, the rename on each side of the merge
1255                 * could also be involved in a rename/add conflict.  In
1256                 * such cases, we should keep the added file around,
1257                 * resolving the conflict at that path in its favor.
1258                 */
1259                add = filespec_from_entry(&other, ci->dst_entry1, 2 ^ 1);
1260                if (add) {
1261                        if (update_file(o, 0, &add->oid, add->mode, a->path))
1262                                return -1;
1263                }
1264                else
1265                        remove_file_from_cache(a->path);
1266                add = filespec_from_entry(&other, ci->dst_entry2, 3 ^ 1);
1267                if (add) {
1268                        if (update_file(o, 0, &add->oid, add->mode, b->path))
1269                                return -1;
1270                }
1271                else
1272                        remove_file_from_cache(b->path);
1273        } else if (handle_file(o, a, 2, ci) || handle_file(o, b, 3, ci))
1274                return -1;
1275
1276        return 0;
1277}
1278
1279static int conflict_rename_rename_2to1(struct merge_options *o,
1280                                        struct rename_conflict_info *ci)
1281{
1282        /* Two files, a & b, were renamed to the same thing, c. */
1283        struct diff_filespec *a = ci->pair1->one;
1284        struct diff_filespec *b = ci->pair2->one;
1285        struct diff_filespec *c1 = ci->pair1->two;
1286        struct diff_filespec *c2 = ci->pair2->two;
1287        char *path = c1->path; /* == c2->path */
1288        struct merge_file_info mfi_c1;
1289        struct merge_file_info mfi_c2;
1290        int ret;
1291
1292        output(o, 1, _("CONFLICT (rename/rename): "
1293               "Rename %s->%s in %s. "
1294               "Rename %s->%s in %s"),
1295               a->path, c1->path, ci->branch1,
1296               b->path, c2->path, ci->branch2);
1297
1298        remove_file(o, 1, a->path, o->call_depth || would_lose_untracked(a->path));
1299        remove_file(o, 1, b->path, o->call_depth || would_lose_untracked(b->path));
1300
1301        if (merge_file_special_markers(o, a, c1, &ci->ren1_other,
1302                                       o->branch1, c1->path,
1303                                       o->branch2, ci->ren1_other.path, &mfi_c1) ||
1304            merge_file_special_markers(o, b, &ci->ren2_other, c2,
1305                                       o->branch1, ci->ren2_other.path,
1306                                       o->branch2, c2->path, &mfi_c2))
1307                return -1;
1308
1309        if (o->call_depth) {
1310                /*
1311                 * If mfi_c1.clean && mfi_c2.clean, then it might make
1312                 * sense to do a two-way merge of those results.  But, I
1313                 * think in all cases, it makes sense to have the virtual
1314                 * merge base just undo the renames; they can be detected
1315                 * again later for the non-recursive merge.
1316                 */
1317                remove_file(o, 0, path, 0);
1318                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, a->path);
1319                if (!ret)
1320                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1321                                          b->path);
1322        } else {
1323                char *new_path1 = unique_path(o, path, ci->branch1);
1324                char *new_path2 = unique_path(o, path, ci->branch2);
1325                output(o, 1, _("Renaming %s to %s and %s to %s instead"),
1326                       a->path, new_path1, b->path, new_path2);
1327                remove_file(o, 0, path, 0);
1328                ret = update_file(o, 0, &mfi_c1.oid, mfi_c1.mode, new_path1);
1329                if (!ret)
1330                        ret = update_file(o, 0, &mfi_c2.oid, mfi_c2.mode,
1331                                          new_path2);
1332                free(new_path2);
1333                free(new_path1);
1334        }
1335
1336        return ret;
1337}
1338
1339static int process_renames(struct merge_options *o,
1340                           struct string_list *a_renames,
1341                           struct string_list *b_renames)
1342{
1343        int clean_merge = 1, i, j;
1344        struct string_list a_by_dst = STRING_LIST_INIT_NODUP;
1345        struct string_list b_by_dst = STRING_LIST_INIT_NODUP;
1346        const struct rename *sre;
1347
1348        for (i = 0; i < a_renames->nr; i++) {
1349                sre = a_renames->items[i].util;
1350                string_list_insert(&a_by_dst, sre->pair->two->path)->util
1351                        = (void *)sre;
1352        }
1353        for (i = 0; i < b_renames->nr; i++) {
1354                sre = b_renames->items[i].util;
1355                string_list_insert(&b_by_dst, sre->pair->two->path)->util
1356                        = (void *)sre;
1357        }
1358
1359        for (i = 0, j = 0; i < a_renames->nr || j < b_renames->nr;) {
1360                struct string_list *renames1, *renames2Dst;
1361                struct rename *ren1 = NULL, *ren2 = NULL;
1362                const char *branch1, *branch2;
1363                const char *ren1_src, *ren1_dst;
1364                struct string_list_item *lookup;
1365
1366                if (i >= a_renames->nr) {
1367                        ren2 = b_renames->items[j++].util;
1368                } else if (j >= b_renames->nr) {
1369                        ren1 = a_renames->items[i++].util;
1370                } else {
1371                        int compare = strcmp(a_renames->items[i].string,
1372                                             b_renames->items[j].string);
1373                        if (compare <= 0)
1374                                ren1 = a_renames->items[i++].util;
1375                        if (compare >= 0)
1376                                ren2 = b_renames->items[j++].util;
1377                }
1378
1379                /* TODO: refactor, so that 1/2 are not needed */
1380                if (ren1) {
1381                        renames1 = a_renames;
1382                        renames2Dst = &b_by_dst;
1383                        branch1 = o->branch1;
1384                        branch2 = o->branch2;
1385                } else {
1386                        renames1 = b_renames;
1387                        renames2Dst = &a_by_dst;
1388                        branch1 = o->branch2;
1389                        branch2 = o->branch1;
1390                        SWAP(ren2, ren1);
1391                }
1392
1393                if (ren1->processed)
1394                        continue;
1395                ren1->processed = 1;
1396                ren1->dst_entry->processed = 1;
1397                /* BUG: We should only mark src_entry as processed if we
1398                 * are not dealing with a rename + add-source case.
1399                 */
1400                ren1->src_entry->processed = 1;
1401
1402                ren1_src = ren1->pair->one->path;
1403                ren1_dst = ren1->pair->two->path;
1404
1405                if (ren2) {
1406                        /* One file renamed on both sides */
1407                        const char *ren2_src = ren2->pair->one->path;
1408                        const char *ren2_dst = ren2->pair->two->path;
1409                        enum rename_type rename_type;
1410                        if (strcmp(ren1_src, ren2_src) != 0)
1411                                die("BUG: ren1_src != ren2_src");
1412                        ren2->dst_entry->processed = 1;
1413                        ren2->processed = 1;
1414                        if (strcmp(ren1_dst, ren2_dst) != 0) {
1415                                rename_type = RENAME_ONE_FILE_TO_TWO;
1416                                clean_merge = 0;
1417                        } else {
1418                                rename_type = RENAME_ONE_FILE_TO_ONE;
1419                                /* BUG: We should only remove ren1_src in
1420                                 * the base stage (think of rename +
1421                                 * add-source cases).
1422                                 */
1423                                remove_file(o, 1, ren1_src, 1);
1424                                update_entry(ren1->dst_entry,
1425                                             ren1->pair->one,
1426                                             ren1->pair->two,
1427                                             ren2->pair->two);
1428                        }
1429                        setup_rename_conflict_info(rename_type,
1430                                                   ren1->pair,
1431                                                   ren2->pair,
1432                                                   branch1,
1433                                                   branch2,
1434                                                   ren1->dst_entry,
1435                                                   ren2->dst_entry,
1436                                                   o,
1437                                                   NULL,
1438                                                   NULL);
1439                } else if ((lookup = string_list_lookup(renames2Dst, ren1_dst))) {
1440                        /* Two different files renamed to the same thing */
1441                        char *ren2_dst;
1442                        ren2 = lookup->util;
1443                        ren2_dst = ren2->pair->two->path;
1444                        if (strcmp(ren1_dst, ren2_dst) != 0)
1445                                die("BUG: ren1_dst != ren2_dst");
1446
1447                        clean_merge = 0;
1448                        ren2->processed = 1;
1449                        /*
1450                         * BUG: We should only mark src_entry as processed
1451                         * if we are not dealing with a rename + add-source
1452                         * case.
1453                         */
1454                        ren2->src_entry->processed = 1;
1455
1456                        setup_rename_conflict_info(RENAME_TWO_FILES_TO_ONE,
1457                                                   ren1->pair,
1458                                                   ren2->pair,
1459                                                   branch1,
1460                                                   branch2,
1461                                                   ren1->dst_entry,
1462                                                   ren2->dst_entry,
1463                                                   o,
1464                                                   ren1->src_entry,
1465                                                   ren2->src_entry);
1466
1467                } else {
1468                        /* Renamed in 1, maybe changed in 2 */
1469                        /* we only use sha1 and mode of these */
1470                        struct diff_filespec src_other, dst_other;
1471                        int try_merge;
1472
1473                        /*
1474                         * unpack_trees loads entries from common-commit
1475                         * into stage 1, from head-commit into stage 2, and
1476                         * from merge-commit into stage 3.  We keep track
1477                         * of which side corresponds to the rename.
1478                         */
1479                        int renamed_stage = a_renames == renames1 ? 2 : 3;
1480                        int other_stage =   a_renames == renames1 ? 3 : 2;
1481
1482                        /* BUG: We should only remove ren1_src in the base
1483                         * stage and in other_stage (think of rename +
1484                         * add-source case).
1485                         */
1486                        remove_file(o, 1, ren1_src,
1487                                    renamed_stage == 2 || !was_tracked(ren1_src));
1488
1489                        oidcpy(&src_other.oid,
1490                               &ren1->src_entry->stages[other_stage].oid);
1491                        src_other.mode = ren1->src_entry->stages[other_stage].mode;
1492                        oidcpy(&dst_other.oid,
1493                               &ren1->dst_entry->stages[other_stage].oid);
1494                        dst_other.mode = ren1->dst_entry->stages[other_stage].mode;
1495                        try_merge = 0;
1496
1497                        if (oid_eq(&src_other.oid, &null_oid)) {
1498                                setup_rename_conflict_info(RENAME_DELETE,
1499                                                           ren1->pair,
1500                                                           NULL,
1501                                                           branch1,
1502                                                           branch2,
1503                                                           ren1->dst_entry,
1504                                                           NULL,
1505                                                           o,
1506                                                           NULL,
1507                                                           NULL);
1508                        } else if ((dst_other.mode == ren1->pair->two->mode) &&
1509                                   oid_eq(&dst_other.oid, &ren1->pair->two->oid)) {
1510                                /*
1511                                 * Added file on the other side identical to
1512                                 * the file being renamed: clean merge.
1513                                 * Also, there is no need to overwrite the
1514                                 * file already in the working copy, so call
1515                                 * update_file_flags() instead of
1516                                 * update_file().
1517                                 */
1518                                if (update_file_flags(o,
1519                                                      &ren1->pair->two->oid,
1520                                                      ren1->pair->two->mode,
1521                                                      ren1_dst,
1522                                                      1, /* update_cache */
1523                                                      0  /* update_wd    */))
1524                                        clean_merge = -1;
1525                        } else if (!oid_eq(&dst_other.oid, &null_oid)) {
1526                                clean_merge = 0;
1527                                try_merge = 1;
1528                                output(o, 1, _("CONFLICT (rename/add): Rename %s->%s in %s. "
1529                                       "%s added in %s"),
1530                                       ren1_src, ren1_dst, branch1,
1531                                       ren1_dst, branch2);
1532                                if (o->call_depth) {
1533                                        struct merge_file_info mfi;
1534                                        if (merge_file_one(o, ren1_dst, &null_oid, 0,
1535                                                           &ren1->pair->two->oid,
1536                                                           ren1->pair->two->mode,
1537                                                           &dst_other.oid,
1538                                                           dst_other.mode,
1539                                                           branch1, branch2, &mfi)) {
1540                                                clean_merge = -1;
1541                                                goto cleanup_and_return;
1542                                        }
1543                                        output(o, 1, _("Adding merged %s"), ren1_dst);
1544                                        if (update_file(o, 0, &mfi.oid,
1545                                                        mfi.mode, ren1_dst))
1546                                                clean_merge = -1;
1547                                        try_merge = 0;
1548                                } else {
1549                                        char *new_path = unique_path(o, ren1_dst, branch2);
1550                                        output(o, 1, _("Adding as %s instead"), new_path);
1551                                        if (update_file(o, 0, &dst_other.oid,
1552                                                        dst_other.mode, new_path))
1553                                                clean_merge = -1;
1554                                        free(new_path);
1555                                }
1556                        } else
1557                                try_merge = 1;
1558
1559                        if (clean_merge < 0)
1560                                goto cleanup_and_return;
1561                        if (try_merge) {
1562                                struct diff_filespec *one, *a, *b;
1563                                src_other.path = (char *)ren1_src;
1564
1565                                one = ren1->pair->one;
1566                                if (a_renames == renames1) {
1567                                        a = ren1->pair->two;
1568                                        b = &src_other;
1569                                } else {
1570                                        b = ren1->pair->two;
1571                                        a = &src_other;
1572                                }
1573                                update_entry(ren1->dst_entry, one, a, b);
1574                                setup_rename_conflict_info(RENAME_NORMAL,
1575                                                           ren1->pair,
1576                                                           NULL,
1577                                                           branch1,
1578                                                           NULL,
1579                                                           ren1->dst_entry,
1580                                                           NULL,
1581                                                           o,
1582                                                           NULL,
1583                                                           NULL);
1584                        }
1585                }
1586        }
1587cleanup_and_return:
1588        string_list_clear(&a_by_dst, 0);
1589        string_list_clear(&b_by_dst, 0);
1590
1591        return clean_merge;
1592}
1593
1594static struct object_id *stage_oid(const struct object_id *oid, unsigned mode)
1595{
1596        return (is_null_oid(oid) || mode == 0) ? NULL: (struct object_id *)oid;
1597}
1598
1599static int read_oid_strbuf(struct merge_options *o,
1600        const struct object_id *oid, struct strbuf *dst)
1601{
1602        void *buf;
1603        enum object_type type;
1604        unsigned long size;
1605        buf = read_sha1_file(oid->hash, &type, &size);
1606        if (!buf)
1607                return err(o, _("cannot read object %s"), oid_to_hex(oid));
1608        if (type != OBJ_BLOB) {
1609                free(buf);
1610                return err(o, _("object %s is not a blob"), oid_to_hex(oid));
1611        }
1612        strbuf_attach(dst, buf, size, size + 1);
1613        return 0;
1614}
1615
1616static int blob_unchanged(struct merge_options *opt,
1617                          const struct object_id *o_oid,
1618                          unsigned o_mode,
1619                          const struct object_id *a_oid,
1620                          unsigned a_mode,
1621                          int renormalize, const char *path)
1622{
1623        struct strbuf o = STRBUF_INIT;
1624        struct strbuf a = STRBUF_INIT;
1625        int ret = 0; /* assume changed for safety */
1626
1627        if (a_mode != o_mode)
1628                return 0;
1629        if (oid_eq(o_oid, a_oid))
1630                return 1;
1631        if (!renormalize)
1632                return 0;
1633
1634        assert(o_oid && a_oid);
1635        if (read_oid_strbuf(opt, o_oid, &o) || read_oid_strbuf(opt, a_oid, &a))
1636                goto error_return;
1637        /*
1638         * Note: binary | is used so that both renormalizations are
1639         * performed.  Comparison can be skipped if both files are
1640         * unchanged since their sha1s have already been compared.
1641         */
1642        if (renormalize_buffer(path, o.buf, o.len, &o) |
1643            renormalize_buffer(path, a.buf, a.len, &a))
1644                ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
1645
1646error_return:
1647        strbuf_release(&o);
1648        strbuf_release(&a);
1649        return ret;
1650}
1651
1652static int handle_modify_delete(struct merge_options *o,
1653                                 const char *path,
1654                                 struct object_id *o_oid, int o_mode,
1655                                 struct object_id *a_oid, int a_mode,
1656                                 struct object_id *b_oid, int b_mode)
1657{
1658        const char *modify_branch, *delete_branch;
1659        struct object_id *changed_oid;
1660        int changed_mode;
1661
1662        if (a_oid) {
1663                modify_branch = o->branch1;
1664                delete_branch = o->branch2;
1665                changed_oid = a_oid;
1666                changed_mode = a_mode;
1667        } else {
1668                modify_branch = o->branch2;
1669                delete_branch = o->branch1;
1670                changed_oid = b_oid;
1671                changed_mode = b_mode;
1672        }
1673
1674        return handle_change_delete(o,
1675                                    path, NULL,
1676                                    o_oid, o_mode,
1677                                    changed_oid, changed_mode,
1678                                    modify_branch, delete_branch,
1679                                    _("modify"), _("modified"));
1680}
1681
1682static int merge_content(struct merge_options *o,
1683                         const char *path,
1684                         struct object_id *o_oid, int o_mode,
1685                         struct object_id *a_oid, int a_mode,
1686                         struct object_id *b_oid, int b_mode,
1687                         struct rename_conflict_info *rename_conflict_info)
1688{
1689        const char *reason = _("content");
1690        const char *path1 = NULL, *path2 = NULL;
1691        struct merge_file_info mfi;
1692        struct diff_filespec one, a, b;
1693        unsigned df_conflict_remains = 0;
1694
1695        if (!o_oid) {
1696                reason = _("add/add");
1697                o_oid = (struct object_id *)&null_oid;
1698        }
1699        one.path = a.path = b.path = (char *)path;
1700        oidcpy(&one.oid, o_oid);
1701        one.mode = o_mode;
1702        oidcpy(&a.oid, a_oid);
1703        a.mode = a_mode;
1704        oidcpy(&b.oid, b_oid);
1705        b.mode = b_mode;
1706
1707        if (rename_conflict_info) {
1708                struct diff_filepair *pair1 = rename_conflict_info->pair1;
1709
1710                path1 = (o->branch1 == rename_conflict_info->branch1) ?
1711                        pair1->two->path : pair1->one->path;
1712                /* If rename_conflict_info->pair2 != NULL, we are in
1713                 * RENAME_ONE_FILE_TO_ONE case.  Otherwise, we have a
1714                 * normal rename.
1715                 */
1716                path2 = (rename_conflict_info->pair2 ||
1717                         o->branch2 == rename_conflict_info->branch1) ?
1718                        pair1->two->path : pair1->one->path;
1719
1720                if (dir_in_way(path, !o->call_depth,
1721                               S_ISGITLINK(pair1->two->mode)))
1722                        df_conflict_remains = 1;
1723        }
1724        if (merge_file_special_markers(o, &one, &a, &b,
1725                                       o->branch1, path1,
1726                                       o->branch2, path2, &mfi))
1727                return -1;
1728
1729        if (mfi.clean && !df_conflict_remains &&
1730            oid_eq(&mfi.oid, a_oid) && mfi.mode == a_mode) {
1731                int path_renamed_outside_HEAD;
1732                output(o, 3, _("Skipped %s (merged same as existing)"), path);
1733                /*
1734                 * The content merge resulted in the same file contents we
1735                 * already had.  We can return early if those file contents
1736                 * are recorded at the correct path (which may not be true
1737                 * if the merge involves a rename).
1738                 */
1739                path_renamed_outside_HEAD = !path2 || !strcmp(path, path2);
1740                if (!path_renamed_outside_HEAD) {
1741                        add_cacheinfo(o, mfi.mode, &mfi.oid, path,
1742                                      0, (!o->call_depth), 0);
1743                        return mfi.clean;
1744                }
1745        } else
1746                output(o, 2, _("Auto-merging %s"), path);
1747
1748        if (!mfi.clean) {
1749                if (S_ISGITLINK(mfi.mode))
1750                        reason = _("submodule");
1751                output(o, 1, _("CONFLICT (%s): Merge conflict in %s"),
1752                                reason, path);
1753                if (rename_conflict_info && !df_conflict_remains)
1754                        if (update_stages(o, path, &one, &a, &b))
1755                                return -1;
1756        }
1757
1758        if (df_conflict_remains) {
1759                char *new_path;
1760                if (o->call_depth) {
1761                        remove_file_from_cache(path);
1762                } else {
1763                        if (!mfi.clean) {
1764                                if (update_stages(o, path, &one, &a, &b))
1765                                        return -1;
1766                        } else {
1767                                int file_from_stage2 = was_tracked(path);
1768                                struct diff_filespec merged;
1769                                oidcpy(&merged.oid, &mfi.oid);
1770                                merged.mode = mfi.mode;
1771
1772                                if (update_stages(o, path, NULL,
1773                                                  file_from_stage2 ? &merged : NULL,
1774                                                  file_from_stage2 ? NULL : &merged))
1775                                        return -1;
1776                        }
1777
1778                }
1779                new_path = unique_path(o, path, rename_conflict_info->branch1);
1780                output(o, 1, _("Adding as %s instead"), new_path);
1781                if (update_file(o, 0, &mfi.oid, mfi.mode, new_path)) {
1782                        free(new_path);
1783                        return -1;
1784                }
1785                free(new_path);
1786                mfi.clean = 0;
1787        } else if (update_file(o, mfi.clean, &mfi.oid, mfi.mode, path))
1788                return -1;
1789        return mfi.clean;
1790}
1791
1792/* Per entry merge function */
1793static int process_entry(struct merge_options *o,
1794                         const char *path, struct stage_data *entry)
1795{
1796        int clean_merge = 1;
1797        int normalize = o->renormalize;
1798        unsigned o_mode = entry->stages[1].mode;
1799        unsigned a_mode = entry->stages[2].mode;
1800        unsigned b_mode = entry->stages[3].mode;
1801        struct object_id *o_oid = stage_oid(&entry->stages[1].oid, o_mode);
1802        struct object_id *a_oid = stage_oid(&entry->stages[2].oid, a_mode);
1803        struct object_id *b_oid = stage_oid(&entry->stages[3].oid, b_mode);
1804
1805        entry->processed = 1;
1806        if (entry->rename_conflict_info) {
1807                struct rename_conflict_info *conflict_info = entry->rename_conflict_info;
1808                switch (conflict_info->rename_type) {
1809                case RENAME_NORMAL:
1810                case RENAME_ONE_FILE_TO_ONE:
1811                        clean_merge = merge_content(o, path,
1812                                                    o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1813                                                    conflict_info);
1814                        break;
1815                case RENAME_DELETE:
1816                        clean_merge = 0;
1817                        if (conflict_rename_delete(o,
1818                                                   conflict_info->pair1,
1819                                                   conflict_info->branch1,
1820                                                   conflict_info->branch2))
1821                                clean_merge = -1;
1822                        break;
1823                case RENAME_ONE_FILE_TO_TWO:
1824                        clean_merge = 0;
1825                        if (conflict_rename_rename_1to2(o, conflict_info))
1826                                clean_merge = -1;
1827                        break;
1828                case RENAME_TWO_FILES_TO_ONE:
1829                        clean_merge = 0;
1830                        if (conflict_rename_rename_2to1(o, conflict_info))
1831                                clean_merge = -1;
1832                        break;
1833                default:
1834                        entry->processed = 0;
1835                        break;
1836                }
1837        } else if (o_oid && (!a_oid || !b_oid)) {
1838                /* Case A: Deleted in one */
1839                if ((!a_oid && !b_oid) ||
1840                    (!b_oid && blob_unchanged(o, o_oid, o_mode, a_oid, a_mode, normalize, path)) ||
1841                    (!a_oid && blob_unchanged(o, o_oid, o_mode, b_oid, b_mode, normalize, path))) {
1842                        /* Deleted in both or deleted in one and
1843                         * unchanged in the other */
1844                        if (a_oid)
1845                                output(o, 2, _("Removing %s"), path);
1846                        /* do not touch working file if it did not exist */
1847                        remove_file(o, 1, path, !a_oid);
1848                } else {
1849                        /* Modify/delete; deleted side may have put a directory in the way */
1850                        clean_merge = 0;
1851                        if (handle_modify_delete(o, path, o_oid, o_mode,
1852                                                 a_oid, a_mode, b_oid, b_mode))
1853                                clean_merge = -1;
1854                }
1855        } else if ((!o_oid && a_oid && !b_oid) ||
1856                   (!o_oid && !a_oid && b_oid)) {
1857                /* Case B: Added in one. */
1858                /* [nothing|directory] -> ([nothing|directory], file) */
1859
1860                const char *add_branch;
1861                const char *other_branch;
1862                unsigned mode;
1863                const struct object_id *oid;
1864                const char *conf;
1865
1866                if (a_oid) {
1867                        add_branch = o->branch1;
1868                        other_branch = o->branch2;
1869                        mode = a_mode;
1870                        oid = a_oid;
1871                        conf = _("file/directory");
1872                } else {
1873                        add_branch = o->branch2;
1874                        other_branch = o->branch1;
1875                        mode = b_mode;
1876                        oid = b_oid;
1877                        conf = _("directory/file");
1878                }
1879                if (dir_in_way(path, !o->call_depth,
1880                               S_ISGITLINK(a_mode))) {
1881                        char *new_path = unique_path(o, path, add_branch);
1882                        clean_merge = 0;
1883                        output(o, 1, _("CONFLICT (%s): There is a directory with name %s in %s. "
1884                               "Adding %s as %s"),
1885                               conf, path, other_branch, path, new_path);
1886                        if (update_file(o, 0, oid, mode, new_path))
1887                                clean_merge = -1;
1888                        else if (o->call_depth)
1889                                remove_file_from_cache(path);
1890                        free(new_path);
1891                } else {
1892                        output(o, 2, _("Adding %s"), path);
1893                        /* do not overwrite file if already present */
1894                        if (update_file_flags(o, oid, mode, path, 1, !a_oid))
1895                                clean_merge = -1;
1896                }
1897        } else if (a_oid && b_oid) {
1898                /* Case C: Added in both (check for same permissions) and */
1899                /* case D: Modified in both, but differently. */
1900                clean_merge = merge_content(o, path,
1901                                            o_oid, o_mode, a_oid, a_mode, b_oid, b_mode,
1902                                            NULL);
1903        } else if (!o_oid && !a_oid && !b_oid) {
1904                /*
1905                 * this entry was deleted altogether. a_mode == 0 means
1906                 * we had that path and want to actively remove it.
1907                 */
1908                remove_file(o, 1, path, !a_mode);
1909        } else
1910                die("BUG: fatal merge failure, shouldn't happen.");
1911
1912        return clean_merge;
1913}
1914
1915int merge_trees(struct merge_options *o,
1916                struct tree *head,
1917                struct tree *merge,
1918                struct tree *common,
1919                struct tree **result)
1920{
1921        int code, clean;
1922
1923        if (o->subtree_shift) {
1924                merge = shift_tree_object(head, merge, o->subtree_shift);
1925                common = shift_tree_object(head, common, o->subtree_shift);
1926        }
1927
1928        if (oid_eq(&common->object.oid, &merge->object.oid)) {
1929                output(o, 0, _("Already up-to-date!"));
1930                *result = head;
1931                return 1;
1932        }
1933
1934        code = git_merge_trees(o->call_depth, common, head, merge);
1935
1936        if (code != 0) {
1937                if (show(o, 4) || o->call_depth)
1938                        err(o, _("merging of trees %s and %s failed"),
1939                            oid_to_hex(&head->object.oid),
1940                            oid_to_hex(&merge->object.oid));
1941                return -1;
1942        }
1943
1944        if (unmerged_cache()) {
1945                struct string_list *entries, *re_head, *re_merge;
1946                int i;
1947                string_list_clear(&o->current_file_set, 1);
1948                string_list_clear(&o->current_directory_set, 1);
1949                get_files_dirs(o, head);
1950                get_files_dirs(o, merge);
1951
1952                entries = get_unmerged();
1953                record_df_conflict_files(o, entries);
1954                re_head  = get_renames(o, head, common, head, merge, entries);
1955                re_merge = get_renames(o, merge, common, head, merge, entries);
1956                clean = process_renames(o, re_head, re_merge);
1957                if (clean < 0)
1958                        return clean;
1959                for (i = entries->nr-1; 0 <= i; i--) {
1960                        const char *path = entries->items[i].string;
1961                        struct stage_data *e = entries->items[i].util;
1962                        if (!e->processed) {
1963                                int ret = process_entry(o, path, e);
1964                                if (!ret)
1965                                        clean = 0;
1966                                else if (ret < 0)
1967                                        return ret;
1968                        }
1969                }
1970                for (i = 0; i < entries->nr; i++) {
1971                        struct stage_data *e = entries->items[i].util;
1972                        if (!e->processed)
1973                                die("BUG: unprocessed path??? %s",
1974                                    entries->items[i].string);
1975                }
1976
1977                string_list_clear(re_merge, 0);
1978                string_list_clear(re_head, 0);
1979                string_list_clear(entries, 1);
1980
1981                free(re_merge);
1982                free(re_head);
1983                free(entries);
1984        }
1985        else
1986                clean = 1;
1987
1988        if (o->call_depth && !(*result = write_tree_from_memory(o)))
1989                return -1;
1990
1991        return clean;
1992}
1993
1994static struct commit_list *reverse_commit_list(struct commit_list *list)
1995{
1996        struct commit_list *next = NULL, *current, *backup;
1997        for (current = list; current; current = backup) {
1998                backup = current->next;
1999                current->next = next;
2000                next = current;
2001        }
2002        return next;
2003}
2004
2005/*
2006 * Merge the commits h1 and h2, return the resulting virtual
2007 * commit object and a flag indicating the cleanness of the merge.
2008 */
2009int merge_recursive(struct merge_options *o,
2010                    struct commit *h1,
2011                    struct commit *h2,
2012                    struct commit_list *ca,
2013                    struct commit **result)
2014{
2015        struct commit_list *iter;
2016        struct commit *merged_common_ancestors;
2017        struct tree *mrtree = mrtree;
2018        int clean;
2019
2020        if (show(o, 4)) {
2021                output(o, 4, _("Merging:"));
2022                output_commit_title(o, h1);
2023                output_commit_title(o, h2);
2024        }
2025
2026        if (!ca) {
2027                ca = get_merge_bases(h1, h2);
2028                ca = reverse_commit_list(ca);
2029        }
2030
2031        if (show(o, 5)) {
2032                unsigned cnt = commit_list_count(ca);
2033
2034                output(o, 5, Q_("found %u common ancestor:",
2035                                "found %u common ancestors:", cnt), cnt);
2036                for (iter = ca; iter; iter = iter->next)
2037                        output_commit_title(o, iter->item);
2038        }
2039
2040        merged_common_ancestors = pop_commit(&ca);
2041        if (merged_common_ancestors == NULL) {
2042                /* if there is no common ancestor, use an empty tree */
2043                struct tree *tree;
2044
2045                tree = lookup_tree(&empty_tree_oid);
2046                merged_common_ancestors = make_virtual_commit(tree, "ancestor");
2047        }
2048
2049        for (iter = ca; iter; iter = iter->next) {
2050                const char *saved_b1, *saved_b2;
2051                o->call_depth++;
2052                /*
2053                 * When the merge fails, the result contains files
2054                 * with conflict markers. The cleanness flag is
2055                 * ignored (unless indicating an error), it was never
2056                 * actually used, as result of merge_trees has always
2057                 * overwritten it: the committed "conflicts" were
2058                 * already resolved.
2059                 */
2060                discard_cache();
2061                saved_b1 = o->branch1;
2062                saved_b2 = o->branch2;
2063                o->branch1 = "Temporary merge branch 1";
2064                o->branch2 = "Temporary merge branch 2";
2065                if (merge_recursive(o, merged_common_ancestors, iter->item,
2066                                    NULL, &merged_common_ancestors) < 0)
2067                        return -1;
2068                o->branch1 = saved_b1;
2069                o->branch2 = saved_b2;
2070                o->call_depth--;
2071
2072                if (!merged_common_ancestors)
2073                        return err(o, _("merge returned no commit"));
2074        }
2075
2076        discard_cache();
2077        if (!o->call_depth)
2078                read_cache();
2079
2080        o->ancestor = "merged common ancestors";
2081        clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
2082                            &mrtree);
2083        if (clean < 0) {
2084                flush_output(o);
2085                return clean;
2086        }
2087
2088        if (o->call_depth) {
2089                *result = make_virtual_commit(mrtree, "merged tree");
2090                commit_list_insert(h1, &(*result)->parents);
2091                commit_list_insert(h2, &(*result)->parents->next);
2092        }
2093        flush_output(o);
2094        if (!o->call_depth && o->buffer_output < 2)
2095                strbuf_release(&o->obuf);
2096        if (show(o, 2))
2097                diff_warn_rename_limit("merge.renamelimit",
2098                                       o->needed_rename_limit, 0);
2099        return clean;
2100}
2101
2102static struct commit *get_ref(const struct object_id *oid, const char *name)
2103{
2104        struct object *object;
2105
2106        object = deref_tag(parse_object(oid), name, strlen(name));
2107        if (!object)
2108                return NULL;
2109        if (object->type == OBJ_TREE)
2110                return make_virtual_commit((struct tree*)object, name);
2111        if (object->type != OBJ_COMMIT)
2112                return NULL;
2113        if (parse_commit((struct commit *)object))
2114                return NULL;
2115        return (struct commit *)object;
2116}
2117
2118int merge_recursive_generic(struct merge_options *o,
2119                            const struct object_id *head,
2120                            const struct object_id *merge,
2121                            int num_base_list,
2122                            const struct object_id **base_list,
2123                            struct commit **result)
2124{
2125        int clean;
2126        struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
2127        struct commit *head_commit = get_ref(head, o->branch1);
2128        struct commit *next_commit = get_ref(merge, o->branch2);
2129        struct commit_list *ca = NULL;
2130
2131        if (base_list) {
2132                int i;
2133                for (i = 0; i < num_base_list; ++i) {
2134                        struct commit *base;
2135                        if (!(base = get_ref(base_list[i], oid_to_hex(base_list[i]))))
2136                                return err(o, _("Could not parse object '%s'"),
2137                                        oid_to_hex(base_list[i]));
2138                        commit_list_insert(base, &ca);
2139                }
2140        }
2141
2142        hold_locked_index(lock, LOCK_DIE_ON_ERROR);
2143        clean = merge_recursive(o, head_commit, next_commit, ca,
2144                        result);
2145        if (clean < 0)
2146                return clean;
2147
2148        if (active_cache_changed &&
2149            write_locked_index(&the_index, lock, COMMIT_LOCK))
2150                return err(o, _("Unable to write index."));
2151
2152        return clean ? 0 : 1;
2153}
2154
2155static void merge_recursive_config(struct merge_options *o)
2156{
2157        git_config_get_int("merge.verbosity", &o->verbosity);
2158        git_config_get_int("diff.renamelimit", &o->diff_rename_limit);
2159        git_config_get_int("merge.renamelimit", &o->merge_rename_limit);
2160        git_config(git_xmerge_config, NULL);
2161}
2162
2163void init_merge_options(struct merge_options *o)
2164{
2165        memset(o, 0, sizeof(struct merge_options));
2166        o->verbosity = 2;
2167        o->buffer_output = 1;
2168        o->diff_rename_limit = -1;
2169        o->merge_rename_limit = -1;
2170        o->renormalize = 0;
2171        o->detect_rename = 1;
2172        merge_recursive_config(o);
2173        if (getenv("GIT_MERGE_VERBOSITY"))
2174                o->verbosity =
2175                        strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
2176        if (o->verbosity >= 5)
2177                o->buffer_output = 0;
2178        strbuf_init(&o->obuf, 0);
2179        string_list_init(&o->current_file_set, 1);
2180        string_list_init(&o->current_directory_set, 1);
2181        string_list_init(&o->df_conflict_file_set, 1);
2182}
2183
2184int parse_merge_opt(struct merge_options *o, const char *s)
2185{
2186        const char *arg;
2187
2188        if (!s || !*s)
2189                return -1;
2190        if (!strcmp(s, "ours"))
2191                o->recursive_variant = MERGE_RECURSIVE_OURS;
2192        else if (!strcmp(s, "theirs"))
2193                o->recursive_variant = MERGE_RECURSIVE_THEIRS;
2194        else if (!strcmp(s, "subtree"))
2195                o->subtree_shift = "";
2196        else if (skip_prefix(s, "subtree=", &arg))
2197                o->subtree_shift = arg;
2198        else if (!strcmp(s, "patience"))
2199                o->xdl_opts = DIFF_WITH_ALG(o, PATIENCE_DIFF);
2200        else if (!strcmp(s, "histogram"))
2201                o->xdl_opts = DIFF_WITH_ALG(o, HISTOGRAM_DIFF);
2202        else if (skip_prefix(s, "diff-algorithm=", &arg)) {
2203                long value = parse_algorithm_value(arg);
2204                if (value < 0)
2205                        return -1;
2206                /* clear out previous settings */
2207                DIFF_XDL_CLR(o, NEED_MINIMAL);
2208                o->xdl_opts &= ~XDF_DIFF_ALGORITHM_MASK;
2209                o->xdl_opts |= value;
2210        }
2211        else if (!strcmp(s, "ignore-space-change"))
2212                o->xdl_opts |= XDF_IGNORE_WHITESPACE_CHANGE;
2213        else if (!strcmp(s, "ignore-all-space"))
2214                o->xdl_opts |= XDF_IGNORE_WHITESPACE;
2215        else if (!strcmp(s, "ignore-space-at-eol"))
2216                o->xdl_opts |= XDF_IGNORE_WHITESPACE_AT_EOL;
2217        else if (!strcmp(s, "renormalize"))
2218                o->renormalize = 1;
2219        else if (!strcmp(s, "no-renormalize"))
2220                o->renormalize = 0;
2221        else if (!strcmp(s, "no-renames"))
2222                o->detect_rename = 0;
2223        else if (!strcmp(s, "find-renames")) {
2224                o->detect_rename = 1;
2225                o->rename_score = 0;
2226        }
2227        else if (skip_prefix(s, "find-renames=", &arg) ||
2228                 skip_prefix(s, "rename-threshold=", &arg)) {
2229                if ((o->rename_score = parse_rename_score(&arg)) == -1 || *arg != 0)
2230                        return -1;
2231                o->detect_rename = 1;
2232        }
2233        else
2234                return -1;
2235        return 0;
2236}