unpack-trees.con commit submodule.c: uninitialized submodules are ignored in recursive commands (823bab0)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "dir.h"
   4#include "tree.h"
   5#include "tree-walk.h"
   6#include "cache-tree.h"
   7#include "unpack-trees.h"
   8#include "progress.h"
   9#include "refs.h"
  10#include "attr.h"
  11#include "split-index.h"
  12#include "dir.h"
  13#include "submodule.h"
  14#include "submodule-config.h"
  15
  16/*
  17 * Error messages expected by scripts out of plumbing commands such as
  18 * read-tree.  Non-scripted Porcelain is not required to use these messages
  19 * and in fact are encouraged to reword them to better suit their particular
  20 * situation better.  See how "git checkout" and "git merge" replaces
  21 * them using setup_unpack_trees_porcelain(), for example.
  22 */
  23static const char *unpack_plumbing_errors[NB_UNPACK_TREES_ERROR_TYPES] = {
  24        /* ERROR_WOULD_OVERWRITE */
  25        "Entry '%s' would be overwritten by merge. Cannot merge.",
  26
  27        /* ERROR_NOT_UPTODATE_FILE */
  28        "Entry '%s' not uptodate. Cannot merge.",
  29
  30        /* ERROR_NOT_UPTODATE_DIR */
  31        "Updating '%s' would lose untracked files in it",
  32
  33        /* ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN */
  34        "Untracked working tree file '%s' would be overwritten by merge.",
  35
  36        /* ERROR_WOULD_LOSE_UNTRACKED_REMOVED */
  37        "Untracked working tree file '%s' would be removed by merge.",
  38
  39        /* ERROR_BIND_OVERLAP */
  40        "Entry '%s' overlaps with '%s'.  Cannot bind.",
  41
  42        /* ERROR_SPARSE_NOT_UPTODATE_FILE */
  43        "Entry '%s' not uptodate. Cannot update sparse checkout.",
  44
  45        /* ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN */
  46        "Working tree file '%s' would be overwritten by sparse checkout update.",
  47
  48        /* ERROR_WOULD_LOSE_ORPHANED_REMOVED */
  49        "Working tree file '%s' would be removed by sparse checkout update.",
  50
  51        /* ERROR_WOULD_LOSE_SUBMODULE */
  52        "Submodule '%s' cannot checkout new HEAD.",
  53};
  54
  55#define ERRORMSG(o,type) \
  56        ( ((o) && (o)->msgs[(type)]) \
  57          ? ((o)->msgs[(type)])      \
  58          : (unpack_plumbing_errors[(type)]) )
  59
  60static const char *super_prefixed(const char *path)
  61{
  62        /*
  63         * It is necessary and sufficient to have two static buffers
  64         * here, as the return value of this function is fed to
  65         * error() using the unpack_*_errors[] templates we see above.
  66         */
  67        static struct strbuf buf[2] = {STRBUF_INIT, STRBUF_INIT};
  68        static int super_prefix_len = -1;
  69        static unsigned idx = ARRAY_SIZE(buf) - 1;
  70
  71        if (super_prefix_len < 0) {
  72                const char *super_prefix = get_super_prefix();
  73                if (!super_prefix) {
  74                        super_prefix_len = 0;
  75                } else {
  76                        int i;
  77                        for (i = 0; i < ARRAY_SIZE(buf); i++)
  78                                strbuf_addstr(&buf[i], super_prefix);
  79                        super_prefix_len = buf[0].len;
  80                }
  81        }
  82
  83        if (!super_prefix_len)
  84                return path;
  85
  86        if (++idx >= ARRAY_SIZE(buf))
  87                idx = 0;
  88
  89        strbuf_setlen(&buf[idx], super_prefix_len);
  90        strbuf_addstr(&buf[idx], path);
  91
  92        return buf[idx].buf;
  93}
  94
  95void setup_unpack_trees_porcelain(struct unpack_trees_options *opts,
  96                                  const char *cmd)
  97{
  98        int i;
  99        const char **msgs = opts->msgs;
 100        const char *msg;
 101
 102        if (!strcmp(cmd, "checkout"))
 103                msg = advice_commit_before_merge
 104                      ? _("Your local changes to the following files would be overwritten by checkout:\n%%s"
 105                          "Please commit your changes or stash them before you switch branches.")
 106                      : _("Your local changes to the following files would be overwritten by checkout:\n%%s");
 107        else if (!strcmp(cmd, "merge"))
 108                msg = advice_commit_before_merge
 109                      ? _("Your local changes to the following files would be overwritten by merge:\n%%s"
 110                          "Please commit your changes or stash them before you merge.")
 111                      : _("Your local changes to the following files would be overwritten by merge:\n%%s");
 112        else
 113                msg = advice_commit_before_merge
 114                      ? _("Your local changes to the following files would be overwritten by %s:\n%%s"
 115                          "Please commit your changes or stash them before you %s.")
 116                      : _("Your local changes to the following files would be overwritten by %s:\n%%s");
 117        msgs[ERROR_WOULD_OVERWRITE] = msgs[ERROR_NOT_UPTODATE_FILE] =
 118                xstrfmt(msg, cmd, cmd);
 119
 120        msgs[ERROR_NOT_UPTODATE_DIR] =
 121                _("Updating the following directories would lose untracked files in them:\n%s");
 122
 123        if (!strcmp(cmd, "checkout"))
 124                msg = advice_commit_before_merge
 125                      ? _("The following untracked working tree files would be removed by checkout:\n%%s"
 126                          "Please move or remove them before you switch branches.")
 127                      : _("The following untracked working tree files would be removed by checkout:\n%%s");
 128        else if (!strcmp(cmd, "merge"))
 129                msg = advice_commit_before_merge
 130                      ? _("The following untracked working tree files would be removed by merge:\n%%s"
 131                          "Please move or remove them before you merge.")
 132                      : _("The following untracked working tree files would be removed by merge:\n%%s");
 133        else
 134                msg = advice_commit_before_merge
 135                      ? _("The following untracked working tree files would be removed by %s:\n%%s"
 136                          "Please move or remove them before you %s.")
 137                      : _("The following untracked working tree files would be removed by %s:\n%%s");
 138        msgs[ERROR_WOULD_LOSE_UNTRACKED_REMOVED] = xstrfmt(msg, cmd, cmd);
 139
 140        if (!strcmp(cmd, "checkout"))
 141                msg = advice_commit_before_merge
 142                      ? _("The following untracked working tree files would be overwritten by checkout:\n%%s"
 143                          "Please move or remove them before you switch branches.")
 144                      : _("The following untracked working tree files would be overwritten by checkout:\n%%s");
 145        else if (!strcmp(cmd, "merge"))
 146                msg = advice_commit_before_merge
 147                      ? _("The following untracked working tree files would be overwritten by merge:\n%%s"
 148                          "Please move or remove them before you merge.")
 149                      : _("The following untracked working tree files would be overwritten by merge:\n%%s");
 150        else
 151                msg = advice_commit_before_merge
 152                      ? _("The following untracked working tree files would be overwritten by %s:\n%%s"
 153                          "Please move or remove them before you %s.")
 154                      : _("The following untracked working tree files would be overwritten by %s:\n%%s");
 155        msgs[ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN] = xstrfmt(msg, cmd, cmd);
 156
 157        /*
 158         * Special case: ERROR_BIND_OVERLAP refers to a pair of paths, we
 159         * cannot easily display it as a list.
 160         */
 161        msgs[ERROR_BIND_OVERLAP] = _("Entry '%s' overlaps with '%s'.  Cannot bind.");
 162
 163        msgs[ERROR_SPARSE_NOT_UPTODATE_FILE] =
 164                _("Cannot update sparse checkout: the following entries are not up-to-date:\n%s");
 165        msgs[ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN] =
 166                _("The following working tree files would be overwritten by sparse checkout update:\n%s");
 167        msgs[ERROR_WOULD_LOSE_ORPHANED_REMOVED] =
 168                _("The following working tree files would be removed by sparse checkout update:\n%s");
 169        msgs[ERROR_WOULD_LOSE_SUBMODULE] =
 170                _("Cannot update submodule:\n%s");
 171
 172        opts->show_all_errors = 1;
 173        /* rejected paths may not have a static buffer */
 174        for (i = 0; i < ARRAY_SIZE(opts->unpack_rejects); i++)
 175                opts->unpack_rejects[i].strdup_strings = 1;
 176}
 177
 178static int do_add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
 179                         unsigned int set, unsigned int clear)
 180{
 181        clear |= CE_HASHED;
 182
 183        if (set & CE_REMOVE)
 184                set |= CE_WT_REMOVE;
 185
 186        ce->ce_flags = (ce->ce_flags & ~clear) | set;
 187        return add_index_entry(&o->result, ce,
 188                               ADD_CACHE_OK_TO_ADD | ADD_CACHE_OK_TO_REPLACE);
 189}
 190
 191static struct cache_entry *dup_entry(const struct cache_entry *ce)
 192{
 193        unsigned int size = ce_size(ce);
 194        struct cache_entry *new = xmalloc(size);
 195
 196        memcpy(new, ce, size);
 197        return new;
 198}
 199
 200static void add_entry(struct unpack_trees_options *o,
 201                      const struct cache_entry *ce,
 202                      unsigned int set, unsigned int clear)
 203{
 204        do_add_entry(o, dup_entry(ce), set, clear);
 205}
 206
 207/*
 208 * add error messages on path <path>
 209 * corresponding to the type <e> with the message <msg>
 210 * indicating if it should be display in porcelain or not
 211 */
 212static int add_rejected_path(struct unpack_trees_options *o,
 213                             enum unpack_trees_error_types e,
 214                             const char *path)
 215{
 216        if (!o->show_all_errors)
 217                return error(ERRORMSG(o, e), super_prefixed(path));
 218
 219        /*
 220         * Otherwise, insert in a list for future display by
 221         * display_error_msgs()
 222         */
 223        string_list_append(&o->unpack_rejects[e], path);
 224        return -1;
 225}
 226
 227/*
 228 * display all the error messages stored in a nice way
 229 */
 230static void display_error_msgs(struct unpack_trees_options *o)
 231{
 232        int e, i;
 233        int something_displayed = 0;
 234        for (e = 0; e < NB_UNPACK_TREES_ERROR_TYPES; e++) {
 235                struct string_list *rejects = &o->unpack_rejects[e];
 236                if (rejects->nr > 0) {
 237                        struct strbuf path = STRBUF_INIT;
 238                        something_displayed = 1;
 239                        for (i = 0; i < rejects->nr; i++)
 240                                strbuf_addf(&path, "\t%s\n", rejects->items[i].string);
 241                        error(ERRORMSG(o, e), super_prefixed(path.buf));
 242                        strbuf_release(&path);
 243                }
 244                string_list_clear(rejects, 0);
 245        }
 246        if (something_displayed)
 247                fprintf(stderr, _("Aborting\n"));
 248}
 249
 250static int check_submodule_move_head(const struct cache_entry *ce,
 251                                     const char *old_id,
 252                                     const char *new_id,
 253                                     struct unpack_trees_options *o)
 254{
 255        unsigned flags = SUBMODULE_MOVE_HEAD_DRY_RUN;
 256        const struct submodule *sub = submodule_from_ce(ce);
 257        if (!sub)
 258                return 0;
 259
 260        if (o->reset)
 261                flags |= SUBMODULE_MOVE_HEAD_FORCE;
 262
 263        switch (sub->update_strategy.type) {
 264        case SM_UPDATE_UNSPECIFIED:
 265        case SM_UPDATE_CHECKOUT:
 266                if (submodule_move_head(ce->name, old_id, new_id, flags))
 267                        return o->gently ? -1 :
 268                                add_rejected_path(o, ERROR_WOULD_LOSE_SUBMODULE, ce->name);
 269                return 0;
 270        case SM_UPDATE_NONE:
 271                return 0;
 272        case SM_UPDATE_REBASE:
 273        case SM_UPDATE_MERGE:
 274        case SM_UPDATE_COMMAND:
 275        default:
 276                warning(_("submodule update strategy not supported for submodule '%s'"), ce->name);
 277                return -1;
 278        }
 279}
 280
 281static void reload_gitmodules_file(struct index_state *index,
 282                                   struct checkout *state)
 283{
 284        int i;
 285        for (i = 0; i < index->cache_nr; i++) {
 286                struct cache_entry *ce = index->cache[i];
 287                if (ce->ce_flags & CE_UPDATE) {
 288                        int r = strcmp(ce->name, ".gitmodules");
 289                        if (r < 0)
 290                                continue;
 291                        else if (r == 0) {
 292                                submodule_free();
 293                                checkout_entry(ce, state, NULL);
 294                                gitmodules_config();
 295                                git_config(submodule_config, NULL);
 296                        } else
 297                                break;
 298                }
 299        }
 300}
 301
 302/*
 303 * Unlink the last component and schedule the leading directories for
 304 * removal, such that empty directories get removed.
 305 */
 306static void unlink_entry(const struct cache_entry *ce)
 307{
 308        const struct submodule *sub = submodule_from_ce(ce);
 309        if (sub) {
 310                switch (sub->update_strategy.type) {
 311                case SM_UPDATE_UNSPECIFIED:
 312                case SM_UPDATE_CHECKOUT:
 313                case SM_UPDATE_REBASE:
 314                case SM_UPDATE_MERGE:
 315                        /* state.force is set at the caller. */
 316                        submodule_move_head(ce->name, "HEAD", NULL,
 317                                            SUBMODULE_MOVE_HEAD_FORCE);
 318                        break;
 319                case SM_UPDATE_NONE:
 320                case SM_UPDATE_COMMAND:
 321                        return; /* Do not touch the submodule. */
 322                }
 323        }
 324        if (!check_leading_path(ce->name, ce_namelen(ce)))
 325                return;
 326        if (remove_or_warn(ce->ce_mode, ce->name))
 327                return;
 328        schedule_dir_for_removal(ce->name, ce_namelen(ce));
 329}
 330
 331static struct progress *get_progress(struct unpack_trees_options *o)
 332{
 333        unsigned cnt = 0, total = 0;
 334        struct index_state *index = &o->result;
 335
 336        if (!o->update || !o->verbose_update)
 337                return NULL;
 338
 339        for (; cnt < index->cache_nr; cnt++) {
 340                const struct cache_entry *ce = index->cache[cnt];
 341                if (ce->ce_flags & (CE_UPDATE | CE_WT_REMOVE))
 342                        total++;
 343        }
 344
 345        return start_progress_delay(_("Checking out files"),
 346                                    total, 50, 1);
 347}
 348
 349static int check_updates(struct unpack_trees_options *o)
 350{
 351        unsigned cnt = 0;
 352        int errs = 0;
 353        struct progress *progress = NULL;
 354        struct index_state *index = &o->result;
 355        struct checkout state = CHECKOUT_INIT;
 356        int i;
 357
 358        state.force = 1;
 359        state.quiet = 1;
 360        state.refresh_cache = 1;
 361        state.istate = index;
 362
 363        progress = get_progress(o);
 364
 365        if (o->update)
 366                git_attr_set_direction(GIT_ATTR_CHECKOUT, index);
 367        for (i = 0; i < index->cache_nr; i++) {
 368                const struct cache_entry *ce = index->cache[i];
 369
 370                if (ce->ce_flags & CE_WT_REMOVE) {
 371                        display_progress(progress, ++cnt);
 372                        if (o->update && !o->dry_run)
 373                                unlink_entry(ce);
 374                }
 375        }
 376        remove_marked_cache_entries(index);
 377        remove_scheduled_dirs();
 378
 379        if (should_update_submodules() && o->update && !o->dry_run)
 380                reload_gitmodules_file(index, &state);
 381
 382        for (i = 0; i < index->cache_nr; i++) {
 383                struct cache_entry *ce = index->cache[i];
 384
 385                if (ce->ce_flags & CE_UPDATE) {
 386                        if (ce->ce_flags & CE_WT_REMOVE)
 387                                die("BUG: both update and delete flags are set on %s",
 388                                    ce->name);
 389                        display_progress(progress, ++cnt);
 390                        ce->ce_flags &= ~CE_UPDATE;
 391                        if (o->update && !o->dry_run) {
 392                                errs |= checkout_entry(ce, &state, NULL);
 393                        }
 394                }
 395        }
 396        stop_progress(&progress);
 397        if (o->update)
 398                git_attr_set_direction(GIT_ATTR_CHECKIN, NULL);
 399        return errs != 0;
 400}
 401
 402static int verify_uptodate_sparse(const struct cache_entry *ce,
 403                                  struct unpack_trees_options *o);
 404static int verify_absent_sparse(const struct cache_entry *ce,
 405                                enum unpack_trees_error_types,
 406                                struct unpack_trees_options *o);
 407
 408static int apply_sparse_checkout(struct index_state *istate,
 409                                 struct cache_entry *ce,
 410                                 struct unpack_trees_options *o)
 411{
 412        int was_skip_worktree = ce_skip_worktree(ce);
 413
 414        if (ce->ce_flags & CE_NEW_SKIP_WORKTREE)
 415                ce->ce_flags |= CE_SKIP_WORKTREE;
 416        else
 417                ce->ce_flags &= ~CE_SKIP_WORKTREE;
 418        if (was_skip_worktree != ce_skip_worktree(ce)) {
 419                ce->ce_flags |= CE_UPDATE_IN_BASE;
 420                istate->cache_changed |= CE_ENTRY_CHANGED;
 421        }
 422
 423        /*
 424         * if (!was_skip_worktree && !ce_skip_worktree()) {
 425         *      This is perfectly normal. Move on;
 426         * }
 427         */
 428
 429        /*
 430         * Merge strategies may set CE_UPDATE|CE_REMOVE outside checkout
 431         * area as a result of ce_skip_worktree() shortcuts in
 432         * verify_absent() and verify_uptodate().
 433         * Make sure they don't modify worktree if they are already
 434         * outside checkout area
 435         */
 436        if (was_skip_worktree && ce_skip_worktree(ce)) {
 437                ce->ce_flags &= ~CE_UPDATE;
 438
 439                /*
 440                 * By default, when CE_REMOVE is on, CE_WT_REMOVE is also
 441                 * on to get that file removed from both index and worktree.
 442                 * If that file is already outside worktree area, don't
 443                 * bother remove it.
 444                 */
 445                if (ce->ce_flags & CE_REMOVE)
 446                        ce->ce_flags &= ~CE_WT_REMOVE;
 447        }
 448
 449        if (!was_skip_worktree && ce_skip_worktree(ce)) {
 450                /*
 451                 * If CE_UPDATE is set, verify_uptodate() must be called already
 452                 * also stat info may have lost after merged_entry() so calling
 453                 * verify_uptodate() again may fail
 454                 */
 455                if (!(ce->ce_flags & CE_UPDATE) && verify_uptodate_sparse(ce, o))
 456                        return -1;
 457                ce->ce_flags |= CE_WT_REMOVE;
 458                ce->ce_flags &= ~CE_UPDATE;
 459        }
 460        if (was_skip_worktree && !ce_skip_worktree(ce)) {
 461                if (verify_absent_sparse(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o))
 462                        return -1;
 463                ce->ce_flags |= CE_UPDATE;
 464        }
 465        return 0;
 466}
 467
 468static inline int call_unpack_fn(const struct cache_entry * const *src,
 469                                 struct unpack_trees_options *o)
 470{
 471        int ret = o->fn(src, o);
 472        if (ret > 0)
 473                ret = 0;
 474        return ret;
 475}
 476
 477static void mark_ce_used(struct cache_entry *ce, struct unpack_trees_options *o)
 478{
 479        ce->ce_flags |= CE_UNPACKED;
 480
 481        if (o->cache_bottom < o->src_index->cache_nr &&
 482            o->src_index->cache[o->cache_bottom] == ce) {
 483                int bottom = o->cache_bottom;
 484                while (bottom < o->src_index->cache_nr &&
 485                       o->src_index->cache[bottom]->ce_flags & CE_UNPACKED)
 486                        bottom++;
 487                o->cache_bottom = bottom;
 488        }
 489}
 490
 491static void mark_all_ce_unused(struct index_state *index)
 492{
 493        int i;
 494        for (i = 0; i < index->cache_nr; i++)
 495                index->cache[i]->ce_flags &= ~(CE_UNPACKED | CE_ADDED | CE_NEW_SKIP_WORKTREE);
 496}
 497
 498static int locate_in_src_index(const struct cache_entry *ce,
 499                               struct unpack_trees_options *o)
 500{
 501        struct index_state *index = o->src_index;
 502        int len = ce_namelen(ce);
 503        int pos = index_name_pos(index, ce->name, len);
 504        if (pos < 0)
 505                pos = -1 - pos;
 506        return pos;
 507}
 508
 509/*
 510 * We call unpack_index_entry() with an unmerged cache entry
 511 * only in diff-index, and it wants a single callback.  Skip
 512 * the other unmerged entry with the same name.
 513 */
 514static void mark_ce_used_same_name(struct cache_entry *ce,
 515                                   struct unpack_trees_options *o)
 516{
 517        struct index_state *index = o->src_index;
 518        int len = ce_namelen(ce);
 519        int pos;
 520
 521        for (pos = locate_in_src_index(ce, o); pos < index->cache_nr; pos++) {
 522                struct cache_entry *next = index->cache[pos];
 523                if (len != ce_namelen(next) ||
 524                    memcmp(ce->name, next->name, len))
 525                        break;
 526                mark_ce_used(next, o);
 527        }
 528}
 529
 530static struct cache_entry *next_cache_entry(struct unpack_trees_options *o)
 531{
 532        const struct index_state *index = o->src_index;
 533        int pos = o->cache_bottom;
 534
 535        while (pos < index->cache_nr) {
 536                struct cache_entry *ce = index->cache[pos];
 537                if (!(ce->ce_flags & CE_UNPACKED))
 538                        return ce;
 539                pos++;
 540        }
 541        return NULL;
 542}
 543
 544static void add_same_unmerged(const struct cache_entry *ce,
 545                              struct unpack_trees_options *o)
 546{
 547        struct index_state *index = o->src_index;
 548        int len = ce_namelen(ce);
 549        int pos = index_name_pos(index, ce->name, len);
 550
 551        if (0 <= pos)
 552                die("programming error in a caller of mark_ce_used_same_name");
 553        for (pos = -pos - 1; pos < index->cache_nr; pos++) {
 554                struct cache_entry *next = index->cache[pos];
 555                if (len != ce_namelen(next) ||
 556                    memcmp(ce->name, next->name, len))
 557                        break;
 558                add_entry(o, next, 0, 0);
 559                mark_ce_used(next, o);
 560        }
 561}
 562
 563static int unpack_index_entry(struct cache_entry *ce,
 564                              struct unpack_trees_options *o)
 565{
 566        const struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 567        int ret;
 568
 569        src[0] = ce;
 570
 571        mark_ce_used(ce, o);
 572        if (ce_stage(ce)) {
 573                if (o->skip_unmerged) {
 574                        add_entry(o, ce, 0, 0);
 575                        return 0;
 576                }
 577        }
 578        ret = call_unpack_fn(src, o);
 579        if (ce_stage(ce))
 580                mark_ce_used_same_name(ce, o);
 581        return ret;
 582}
 583
 584static int find_cache_pos(struct traverse_info *, const struct name_entry *);
 585
 586static void restore_cache_bottom(struct traverse_info *info, int bottom)
 587{
 588        struct unpack_trees_options *o = info->data;
 589
 590        if (o->diff_index_cached)
 591                return;
 592        o->cache_bottom = bottom;
 593}
 594
 595static int switch_cache_bottom(struct traverse_info *info)
 596{
 597        struct unpack_trees_options *o = info->data;
 598        int ret, pos;
 599
 600        if (o->diff_index_cached)
 601                return 0;
 602        ret = o->cache_bottom;
 603        pos = find_cache_pos(info->prev, &info->name);
 604
 605        if (pos < -1)
 606                o->cache_bottom = -2 - pos;
 607        else if (pos < 0)
 608                o->cache_bottom = o->src_index->cache_nr;
 609        return ret;
 610}
 611
 612static int traverse_trees_recursive(int n, unsigned long dirmask,
 613                                    unsigned long df_conflicts,
 614                                    struct name_entry *names,
 615                                    struct traverse_info *info)
 616{
 617        int i, ret, bottom;
 618        struct tree_desc t[MAX_UNPACK_TREES];
 619        void *buf[MAX_UNPACK_TREES];
 620        struct traverse_info newinfo;
 621        struct name_entry *p;
 622
 623        p = names;
 624        while (!p->mode)
 625                p++;
 626
 627        newinfo = *info;
 628        newinfo.prev = info;
 629        newinfo.pathspec = info->pathspec;
 630        newinfo.name = *p;
 631        newinfo.pathlen += tree_entry_len(p) + 1;
 632        newinfo.df_conflicts |= df_conflicts;
 633
 634        for (i = 0; i < n; i++, dirmask >>= 1) {
 635                const unsigned char *sha1 = NULL;
 636                if (dirmask & 1)
 637                        sha1 = names[i].oid->hash;
 638                buf[i] = fill_tree_descriptor(t+i, sha1);
 639        }
 640
 641        bottom = switch_cache_bottom(&newinfo);
 642        ret = traverse_trees(n, t, &newinfo);
 643        restore_cache_bottom(&newinfo, bottom);
 644
 645        for (i = 0; i < n; i++)
 646                free(buf[i]);
 647
 648        return ret;
 649}
 650
 651/*
 652 * Compare the traverse-path to the cache entry without actually
 653 * having to generate the textual representation of the traverse
 654 * path.
 655 *
 656 * NOTE! This *only* compares up to the size of the traverse path
 657 * itself - the caller needs to do the final check for the cache
 658 * entry having more data at the end!
 659 */
 660static int do_compare_entry_piecewise(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 661{
 662        int len, pathlen, ce_len;
 663        const char *ce_name;
 664
 665        if (info->prev) {
 666                int cmp = do_compare_entry_piecewise(ce, info->prev,
 667                                                     &info->name);
 668                if (cmp)
 669                        return cmp;
 670        }
 671        pathlen = info->pathlen;
 672        ce_len = ce_namelen(ce);
 673
 674        /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
 675        if (ce_len < pathlen)
 676                return -1;
 677
 678        ce_len -= pathlen;
 679        ce_name = ce->name + pathlen;
 680
 681        len = tree_entry_len(n);
 682        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 683}
 684
 685static int do_compare_entry(const struct cache_entry *ce,
 686                            const struct traverse_info *info,
 687                            const struct name_entry *n)
 688{
 689        int len, pathlen, ce_len;
 690        const char *ce_name;
 691        int cmp;
 692
 693        /*
 694         * If we have not precomputed the traverse path, it is quicker
 695         * to avoid doing so.  But if we have precomputed it,
 696         * it is quicker to use the precomputed version.
 697         */
 698        if (!info->traverse_path)
 699                return do_compare_entry_piecewise(ce, info, n);
 700
 701        cmp = strncmp(ce->name, info->traverse_path, info->pathlen);
 702        if (cmp)
 703                return cmp;
 704
 705        pathlen = info->pathlen;
 706        ce_len = ce_namelen(ce);
 707
 708        if (ce_len < pathlen)
 709                return -1;
 710
 711        ce_len -= pathlen;
 712        ce_name = ce->name + pathlen;
 713
 714        len = tree_entry_len(n);
 715        return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
 716}
 717
 718static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
 719{
 720        int cmp = do_compare_entry(ce, info, n);
 721        if (cmp)
 722                return cmp;
 723
 724        /*
 725         * Even if the beginning compared identically, the ce should
 726         * compare as bigger than a directory leading up to it!
 727         */
 728        return ce_namelen(ce) > traverse_path_len(info, n);
 729}
 730
 731static int ce_in_traverse_path(const struct cache_entry *ce,
 732                               const struct traverse_info *info)
 733{
 734        if (!info->prev)
 735                return 1;
 736        if (do_compare_entry(ce, info->prev, &info->name))
 737                return 0;
 738        /*
 739         * If ce (blob) is the same name as the path (which is a tree
 740         * we will be descending into), it won't be inside it.
 741         */
 742        return (info->pathlen < ce_namelen(ce));
 743}
 744
 745static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
 746{
 747        int len = traverse_path_len(info, n);
 748        struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
 749
 750        ce->ce_mode = create_ce_mode(n->mode);
 751        ce->ce_flags = create_ce_flags(stage);
 752        ce->ce_namelen = len;
 753        oidcpy(&ce->oid, n->oid);
 754        make_traverse_path(ce->name, info, n);
 755
 756        return ce;
 757}
 758
 759static int unpack_nondirectories(int n, unsigned long mask,
 760                                 unsigned long dirmask,
 761                                 struct cache_entry **src,
 762                                 const struct name_entry *names,
 763                                 const struct traverse_info *info)
 764{
 765        int i;
 766        struct unpack_trees_options *o = info->data;
 767        unsigned long conflicts = info->df_conflicts | dirmask;
 768
 769        /* Do we have *only* directories? Nothing to do */
 770        if (mask == dirmask && !src[0])
 771                return 0;
 772
 773        /*
 774         * Ok, we've filled in up to any potential index entry in src[0],
 775         * now do the rest.
 776         */
 777        for (i = 0; i < n; i++) {
 778                int stage;
 779                unsigned int bit = 1ul << i;
 780                if (conflicts & bit) {
 781                        src[i + o->merge] = o->df_conflict_entry;
 782                        continue;
 783                }
 784                if (!(mask & bit))
 785                        continue;
 786                if (!o->merge)
 787                        stage = 0;
 788                else if (i + 1 < o->head_idx)
 789                        stage = 1;
 790                else if (i + 1 > o->head_idx)
 791                        stage = 3;
 792                else
 793                        stage = 2;
 794                src[i + o->merge] = create_ce_entry(info, names + i, stage);
 795        }
 796
 797        if (o->merge) {
 798                int rc = call_unpack_fn((const struct cache_entry * const *)src,
 799                                        o);
 800                for (i = 0; i < n; i++) {
 801                        struct cache_entry *ce = src[i + o->merge];
 802                        if (ce != o->df_conflict_entry)
 803                                free(ce);
 804                }
 805                return rc;
 806        }
 807
 808        for (i = 0; i < n; i++)
 809                if (src[i] && src[i] != o->df_conflict_entry)
 810                        if (do_add_entry(o, src[i], 0, 0))
 811                                return -1;
 812
 813        return 0;
 814}
 815
 816static int unpack_failed(struct unpack_trees_options *o, const char *message)
 817{
 818        discard_index(&o->result);
 819        if (!o->gently && !o->exiting_early) {
 820                if (message)
 821                        return error("%s", message);
 822                return -1;
 823        }
 824        return -1;
 825}
 826
 827/*
 828 * The tree traversal is looking at name p.  If we have a matching entry,
 829 * return it.  If name p is a directory in the index, do not return
 830 * anything, as we will want to match it when the traversal descends into
 831 * the directory.
 832 */
 833static int find_cache_pos(struct traverse_info *info,
 834                          const struct name_entry *p)
 835{
 836        int pos;
 837        struct unpack_trees_options *o = info->data;
 838        struct index_state *index = o->src_index;
 839        int pfxlen = info->pathlen;
 840        int p_len = tree_entry_len(p);
 841
 842        for (pos = o->cache_bottom; pos < index->cache_nr; pos++) {
 843                const struct cache_entry *ce = index->cache[pos];
 844                const char *ce_name, *ce_slash;
 845                int cmp, ce_len;
 846
 847                if (ce->ce_flags & CE_UNPACKED) {
 848                        /*
 849                         * cache_bottom entry is already unpacked, so
 850                         * we can never match it; don't check it
 851                         * again.
 852                         */
 853                        if (pos == o->cache_bottom)
 854                                ++o->cache_bottom;
 855                        continue;
 856                }
 857                if (!ce_in_traverse_path(ce, info)) {
 858                        /*
 859                         * Check if we can skip future cache checks
 860                         * (because we're already past all possible
 861                         * entries in the traverse path).
 862                         */
 863                        if (info->traverse_path) {
 864                                if (strncmp(ce->name, info->traverse_path,
 865                                            info->pathlen) > 0)
 866                                        break;
 867                        }
 868                        continue;
 869                }
 870                ce_name = ce->name + pfxlen;
 871                ce_slash = strchr(ce_name, '/');
 872                if (ce_slash)
 873                        ce_len = ce_slash - ce_name;
 874                else
 875                        ce_len = ce_namelen(ce) - pfxlen;
 876                cmp = name_compare(p->path, p_len, ce_name, ce_len);
 877                /*
 878                 * Exact match; if we have a directory we need to
 879                 * delay returning it.
 880                 */
 881                if (!cmp)
 882                        return ce_slash ? -2 - pos : pos;
 883                if (0 < cmp)
 884                        continue; /* keep looking */
 885                /*
 886                 * ce_name sorts after p->path; could it be that we
 887                 * have files under p->path directory in the index?
 888                 * E.g.  ce_name == "t-i", and p->path == "t"; we may
 889                 * have "t/a" in the index.
 890                 */
 891                if (p_len < ce_len && !memcmp(ce_name, p->path, p_len) &&
 892                    ce_name[p_len] < '/')
 893                        continue; /* keep looking */
 894                break;
 895        }
 896        return -1;
 897}
 898
 899static struct cache_entry *find_cache_entry(struct traverse_info *info,
 900                                            const struct name_entry *p)
 901{
 902        int pos = find_cache_pos(info, p);
 903        struct unpack_trees_options *o = info->data;
 904
 905        if (0 <= pos)
 906                return o->src_index->cache[pos];
 907        else
 908                return NULL;
 909}
 910
 911static void debug_path(struct traverse_info *info)
 912{
 913        if (info->prev) {
 914                debug_path(info->prev);
 915                if (*info->prev->name.path)
 916                        putchar('/');
 917        }
 918        printf("%s", info->name.path);
 919}
 920
 921static void debug_name_entry(int i, struct name_entry *n)
 922{
 923        printf("ent#%d %06o %s\n", i,
 924               n->path ? n->mode : 0,
 925               n->path ? n->path : "(missing)");
 926}
 927
 928static void debug_unpack_callback(int n,
 929                                  unsigned long mask,
 930                                  unsigned long dirmask,
 931                                  struct name_entry *names,
 932                                  struct traverse_info *info)
 933{
 934        int i;
 935        printf("* unpack mask %lu, dirmask %lu, cnt %d ",
 936               mask, dirmask, n);
 937        debug_path(info);
 938        putchar('\n');
 939        for (i = 0; i < n; i++)
 940                debug_name_entry(i, names + i);
 941}
 942
 943static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
 944{
 945        struct cache_entry *src[MAX_UNPACK_TREES + 1] = { NULL, };
 946        struct unpack_trees_options *o = info->data;
 947        const struct name_entry *p = names;
 948
 949        /* Find first entry with a real name (we could use "mask" too) */
 950        while (!p->mode)
 951                p++;
 952
 953        if (o->debug_unpack)
 954                debug_unpack_callback(n, mask, dirmask, names, info);
 955
 956        /* Are we supposed to look at the index too? */
 957        if (o->merge) {
 958                while (1) {
 959                        int cmp;
 960                        struct cache_entry *ce;
 961
 962                        if (o->diff_index_cached)
 963                                ce = next_cache_entry(o);
 964                        else
 965                                ce = find_cache_entry(info, p);
 966
 967                        if (!ce)
 968                                break;
 969                        cmp = compare_entry(ce, info, p);
 970                        if (cmp < 0) {
 971                                if (unpack_index_entry(ce, o) < 0)
 972                                        return unpack_failed(o, NULL);
 973                                continue;
 974                        }
 975                        if (!cmp) {
 976                                if (ce_stage(ce)) {
 977                                        /*
 978                                         * If we skip unmerged index
 979                                         * entries, we'll skip this
 980                                         * entry *and* the tree
 981                                         * entries associated with it!
 982                                         */
 983                                        if (o->skip_unmerged) {
 984                                                add_same_unmerged(ce, o);
 985                                                return mask;
 986                                        }
 987                                }
 988                                src[0] = ce;
 989                        }
 990                        break;
 991                }
 992        }
 993
 994        if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
 995                return -1;
 996
 997        if (o->merge && src[0]) {
 998                if (ce_stage(src[0]))
 999                        mark_ce_used_same_name(src[0], o);
1000                else
1001                        mark_ce_used(src[0], o);
1002        }
1003
1004        /* Now handle any directories.. */
1005        if (dirmask) {
1006                /* special case: "diff-index --cached" looking at a tree */
1007                if (o->diff_index_cached &&
1008                    n == 1 && dirmask == 1 && S_ISDIR(names->mode)) {
1009                        int matches;
1010                        matches = cache_tree_matches_traversal(o->src_index->cache_tree,
1011                                                               names, info);
1012                        /*
1013                         * Everything under the name matches; skip the
1014                         * entire hierarchy.  diff_index_cached codepath
1015                         * special cases D/F conflicts in such a way that
1016                         * it does not do any look-ahead, so this is safe.
1017                         */
1018                        if (matches) {
1019                                o->cache_bottom += matches;
1020                                return mask;
1021                        }
1022                }
1023
1024                if (traverse_trees_recursive(n, dirmask, mask & ~dirmask,
1025                                             names, info) < 0)
1026                        return -1;
1027                return mask;
1028        }
1029
1030        return mask;
1031}
1032
1033static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1034                            struct strbuf *prefix,
1035                            int select_mask, int clear_mask,
1036                            struct exclude_list *el, int defval);
1037
1038/* Whole directory matching */
1039static int clear_ce_flags_dir(struct cache_entry **cache, int nr,
1040                              struct strbuf *prefix,
1041                              char *basename,
1042                              int select_mask, int clear_mask,
1043                              struct exclude_list *el, int defval)
1044{
1045        struct cache_entry **cache_end;
1046        int dtype = DT_DIR;
1047        int ret = is_excluded_from_list(prefix->buf, prefix->len,
1048                                        basename, &dtype, el);
1049        int rc;
1050
1051        strbuf_addch(prefix, '/');
1052
1053        /* If undecided, use matching result of parent dir in defval */
1054        if (ret < 0)
1055                ret = defval;
1056
1057        for (cache_end = cache; cache_end != cache + nr; cache_end++) {
1058                struct cache_entry *ce = *cache_end;
1059                if (strncmp(ce->name, prefix->buf, prefix->len))
1060                        break;
1061        }
1062
1063        /*
1064         * TODO: check el, if there are no patterns that may conflict
1065         * with ret (iow, we know in advance the incl/excl
1066         * decision for the entire directory), clear flag here without
1067         * calling clear_ce_flags_1(). That function will call
1068         * the expensive is_excluded_from_list() on every entry.
1069         */
1070        rc = clear_ce_flags_1(cache, cache_end - cache,
1071                              prefix,
1072                              select_mask, clear_mask,
1073                              el, ret);
1074        strbuf_setlen(prefix, prefix->len - 1);
1075        return rc;
1076}
1077
1078/*
1079 * Traverse the index, find every entry that matches according to
1080 * o->el. Do "ce_flags &= ~clear_mask" on those entries. Return the
1081 * number of traversed entries.
1082 *
1083 * If select_mask is non-zero, only entries whose ce_flags has on of
1084 * those bits enabled are traversed.
1085 *
1086 * cache        : pointer to an index entry
1087 * prefix_len   : an offset to its path
1088 *
1089 * The current path ("prefix") including the trailing '/' is
1090 *   cache[0]->name[0..(prefix_len-1)]
1091 * Top level path has prefix_len zero.
1092 */
1093static int clear_ce_flags_1(struct cache_entry **cache, int nr,
1094                            struct strbuf *prefix,
1095                            int select_mask, int clear_mask,
1096                            struct exclude_list *el, int defval)
1097{
1098        struct cache_entry **cache_end = cache + nr;
1099
1100        /*
1101         * Process all entries that have the given prefix and meet
1102         * select_mask condition
1103         */
1104        while(cache != cache_end) {
1105                struct cache_entry *ce = *cache;
1106                const char *name, *slash;
1107                int len, dtype, ret;
1108
1109                if (select_mask && !(ce->ce_flags & select_mask)) {
1110                        cache++;
1111                        continue;
1112                }
1113
1114                if (prefix->len && strncmp(ce->name, prefix->buf, prefix->len))
1115                        break;
1116
1117                name = ce->name + prefix->len;
1118                slash = strchr(name, '/');
1119
1120                /* If it's a directory, try whole directory match first */
1121                if (slash) {
1122                        int processed;
1123
1124                        len = slash - name;
1125                        strbuf_add(prefix, name, len);
1126
1127                        processed = clear_ce_flags_dir(cache, cache_end - cache,
1128                                                       prefix,
1129                                                       prefix->buf + prefix->len - len,
1130                                                       select_mask, clear_mask,
1131                                                       el, defval);
1132
1133                        /* clear_c_f_dir eats a whole dir already? */
1134                        if (processed) {
1135                                cache += processed;
1136                                strbuf_setlen(prefix, prefix->len - len);
1137                                continue;
1138                        }
1139
1140                        strbuf_addch(prefix, '/');
1141                        cache += clear_ce_flags_1(cache, cache_end - cache,
1142                                                  prefix,
1143                                                  select_mask, clear_mask, el, defval);
1144                        strbuf_setlen(prefix, prefix->len - len - 1);
1145                        continue;
1146                }
1147
1148                /* Non-directory */
1149                dtype = ce_to_dtype(ce);
1150                ret = is_excluded_from_list(ce->name, ce_namelen(ce),
1151                                            name, &dtype, el);
1152                if (ret < 0)
1153                        ret = defval;
1154                if (ret > 0)
1155                        ce->ce_flags &= ~clear_mask;
1156                cache++;
1157        }
1158        return nr - (cache_end - cache);
1159}
1160
1161static int clear_ce_flags(struct cache_entry **cache, int nr,
1162                            int select_mask, int clear_mask,
1163                            struct exclude_list *el)
1164{
1165        static struct strbuf prefix = STRBUF_INIT;
1166
1167        strbuf_reset(&prefix);
1168
1169        return clear_ce_flags_1(cache, nr,
1170                                &prefix,
1171                                select_mask, clear_mask,
1172                                el, 0);
1173}
1174
1175/*
1176 * Set/Clear CE_NEW_SKIP_WORKTREE according to $GIT_DIR/info/sparse-checkout
1177 */
1178static void mark_new_skip_worktree(struct exclude_list *el,
1179                                   struct index_state *the_index,
1180                                   int select_flag, int skip_wt_flag)
1181{
1182        int i;
1183
1184        /*
1185         * 1. Pretend the narrowest worktree: only unmerged entries
1186         * are checked out
1187         */
1188        for (i = 0; i < the_index->cache_nr; i++) {
1189                struct cache_entry *ce = the_index->cache[i];
1190
1191                if (select_flag && !(ce->ce_flags & select_flag))
1192                        continue;
1193
1194                if (!ce_stage(ce))
1195                        ce->ce_flags |= skip_wt_flag;
1196                else
1197                        ce->ce_flags &= ~skip_wt_flag;
1198        }
1199
1200        /*
1201         * 2. Widen worktree according to sparse-checkout file.
1202         * Matched entries will have skip_wt_flag cleared (i.e. "in")
1203         */
1204        clear_ce_flags(the_index->cache, the_index->cache_nr,
1205                       select_flag, skip_wt_flag, el);
1206}
1207
1208static int verify_absent(const struct cache_entry *,
1209                         enum unpack_trees_error_types,
1210                         struct unpack_trees_options *);
1211/*
1212 * N-way merge "len" trees.  Returns 0 on success, -1 on failure to manipulate the
1213 * resulting index, -2 on failure to reflect the changes to the work tree.
1214 *
1215 * CE_ADDED, CE_UNPACKED and CE_NEW_SKIP_WORKTREE are used internally
1216 */
1217int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
1218{
1219        int i, ret;
1220        static struct cache_entry *dfc;
1221        struct exclude_list el;
1222
1223        if (len > MAX_UNPACK_TREES)
1224                die("unpack_trees takes at most %d trees", MAX_UNPACK_TREES);
1225
1226        memset(&el, 0, sizeof(el));
1227        if (!core_apply_sparse_checkout || !o->update)
1228                o->skip_sparse_checkout = 1;
1229        if (!o->skip_sparse_checkout) {
1230                char *sparse = git_pathdup("info/sparse-checkout");
1231                if (add_excludes_from_file_to_list(sparse, "", 0, &el, 0) < 0)
1232                        o->skip_sparse_checkout = 1;
1233                else
1234                        o->el = &el;
1235                free(sparse);
1236        }
1237
1238        memset(&o->result, 0, sizeof(o->result));
1239        o->result.initialized = 1;
1240        o->result.timestamp.sec = o->src_index->timestamp.sec;
1241        o->result.timestamp.nsec = o->src_index->timestamp.nsec;
1242        o->result.version = o->src_index->version;
1243        o->result.split_index = o->src_index->split_index;
1244        if (o->result.split_index)
1245                o->result.split_index->refcount++;
1246        hashcpy(o->result.sha1, o->src_index->sha1);
1247        o->merge_size = len;
1248        mark_all_ce_unused(o->src_index);
1249
1250        /*
1251         * Sparse checkout loop #1: set NEW_SKIP_WORKTREE on existing entries
1252         */
1253        if (!o->skip_sparse_checkout)
1254                mark_new_skip_worktree(o->el, o->src_index, 0, CE_NEW_SKIP_WORKTREE);
1255
1256        if (!dfc)
1257                dfc = xcalloc(1, cache_entry_size(0));
1258        o->df_conflict_entry = dfc;
1259
1260        if (len) {
1261                const char *prefix = o->prefix ? o->prefix : "";
1262                struct traverse_info info;
1263
1264                setup_traverse_info(&info, prefix);
1265                info.fn = unpack_callback;
1266                info.data = o;
1267                info.show_all_errors = o->show_all_errors;
1268                info.pathspec = o->pathspec;
1269
1270                if (o->prefix) {
1271                        /*
1272                         * Unpack existing index entries that sort before the
1273                         * prefix the tree is spliced into.  Note that o->merge
1274                         * is always true in this case.
1275                         */
1276                        while (1) {
1277                                struct cache_entry *ce = next_cache_entry(o);
1278                                if (!ce)
1279                                        break;
1280                                if (ce_in_traverse_path(ce, &info))
1281                                        break;
1282                                if (unpack_index_entry(ce, o) < 0)
1283                                        goto return_failed;
1284                        }
1285                }
1286
1287                if (traverse_trees(len, t, &info) < 0)
1288                        goto return_failed;
1289        }
1290
1291        /* Any left-over entries in the index? */
1292        if (o->merge) {
1293                while (1) {
1294                        struct cache_entry *ce = next_cache_entry(o);
1295                        if (!ce)
1296                                break;
1297                        if (unpack_index_entry(ce, o) < 0)
1298                                goto return_failed;
1299                }
1300        }
1301        mark_all_ce_unused(o->src_index);
1302
1303        if (o->trivial_merges_only && o->nontrivial_merge) {
1304                ret = unpack_failed(o, "Merge requires file-level merging");
1305                goto done;
1306        }
1307
1308        if (!o->skip_sparse_checkout) {
1309                int empty_worktree = 1;
1310
1311                /*
1312                 * Sparse checkout loop #2: set NEW_SKIP_WORKTREE on entries not in loop #1
1313                 * If the will have NEW_SKIP_WORKTREE, also set CE_SKIP_WORKTREE
1314                 * so apply_sparse_checkout() won't attempt to remove it from worktree
1315                 */
1316                mark_new_skip_worktree(o->el, &o->result, CE_ADDED, CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1317
1318                ret = 0;
1319                for (i = 0; i < o->result.cache_nr; i++) {
1320                        struct cache_entry *ce = o->result.cache[i];
1321
1322                        /*
1323                         * Entries marked with CE_ADDED in merged_entry() do not have
1324                         * verify_absent() check (the check is effectively disabled
1325                         * because CE_NEW_SKIP_WORKTREE is set unconditionally).
1326                         *
1327                         * Do the real check now because we have had
1328                         * correct CE_NEW_SKIP_WORKTREE
1329                         */
1330                        if (ce->ce_flags & CE_ADDED &&
1331                            verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1332                                if (!o->show_all_errors)
1333                                        goto return_failed;
1334                                ret = -1;
1335                        }
1336
1337                        if (apply_sparse_checkout(&o->result, ce, o)) {
1338                                if (!o->show_all_errors)
1339                                        goto return_failed;
1340                                ret = -1;
1341                        }
1342                        if (!ce_skip_worktree(ce))
1343                                empty_worktree = 0;
1344
1345                }
1346                if (ret < 0)
1347                        goto return_failed;
1348                /*
1349                 * Sparse checkout is meant to narrow down checkout area
1350                 * but it does not make sense to narrow down to empty working
1351                 * tree. This is usually a mistake in sparse checkout rules.
1352                 * Do not allow users to do that.
1353                 */
1354                if (o->result.cache_nr && empty_worktree) {
1355                        ret = unpack_failed(o, "Sparse checkout leaves no entry on working directory");
1356                        goto done;
1357                }
1358        }
1359
1360        o->src_index = NULL;
1361        ret = check_updates(o) ? (-2) : 0;
1362        if (o->dst_index) {
1363                if (!ret) {
1364                        if (!o->result.cache_tree)
1365                                o->result.cache_tree = cache_tree();
1366                        if (!cache_tree_fully_valid(o->result.cache_tree))
1367                                cache_tree_update(&o->result,
1368                                                  WRITE_TREE_SILENT |
1369                                                  WRITE_TREE_REPAIR);
1370                }
1371                discard_index(o->dst_index);
1372                *o->dst_index = o->result;
1373        } else {
1374                discard_index(&o->result);
1375        }
1376
1377done:
1378        clear_exclude_list(&el);
1379        return ret;
1380
1381return_failed:
1382        if (o->show_all_errors)
1383                display_error_msgs(o);
1384        mark_all_ce_unused(o->src_index);
1385        ret = unpack_failed(o, NULL);
1386        if (o->exiting_early)
1387                ret = 0;
1388        goto done;
1389}
1390
1391/* Here come the merge functions */
1392
1393static int reject_merge(const struct cache_entry *ce,
1394                        struct unpack_trees_options *o)
1395{
1396        return o->gently ? -1 :
1397                add_rejected_path(o, ERROR_WOULD_OVERWRITE, ce->name);
1398}
1399
1400static int same(const struct cache_entry *a, const struct cache_entry *b)
1401{
1402        if (!!a != !!b)
1403                return 0;
1404        if (!a && !b)
1405                return 1;
1406        if ((a->ce_flags | b->ce_flags) & CE_CONFLICTED)
1407                return 0;
1408        return a->ce_mode == b->ce_mode &&
1409               !oidcmp(&a->oid, &b->oid);
1410}
1411
1412
1413/*
1414 * When a CE gets turned into an unmerged entry, we
1415 * want it to be up-to-date
1416 */
1417static int verify_uptodate_1(const struct cache_entry *ce,
1418                             struct unpack_trees_options *o,
1419                             enum unpack_trees_error_types error_type)
1420{
1421        struct stat st;
1422
1423        if (o->index_only)
1424                return 0;
1425
1426        /*
1427         * CE_VALID and CE_SKIP_WORKTREE cheat, we better check again
1428         * if this entry is truly up-to-date because this file may be
1429         * overwritten.
1430         */
1431        if ((ce->ce_flags & CE_VALID) || ce_skip_worktree(ce))
1432                ; /* keep checking */
1433        else if (o->reset || ce_uptodate(ce))
1434                return 0;
1435
1436        if (!lstat(ce->name, &st)) {
1437                int flags = CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE;
1438                unsigned changed = ie_match_stat(o->src_index, ce, &st, flags);
1439
1440                if (submodule_from_ce(ce)) {
1441                        int r = check_submodule_move_head(ce,
1442                                "HEAD", oid_to_hex(&ce->oid), o);
1443                        if (r)
1444                                return o->gently ? -1 :
1445                                        add_rejected_path(o, error_type, ce->name);
1446                        return 0;
1447                }
1448
1449                if (!changed)
1450                        return 0;
1451                /*
1452                 * Historic default policy was to allow submodule to be out
1453                 * of sync wrt the superproject index. If the submodule was
1454                 * not considered interesting above, we don't care here.
1455                 */
1456                if (S_ISGITLINK(ce->ce_mode))
1457                        return 0;
1458
1459                errno = 0;
1460        }
1461        if (errno == ENOENT)
1462                return 0;
1463        return o->gently ? -1 :
1464                add_rejected_path(o, error_type, ce->name);
1465}
1466
1467static int verify_uptodate(const struct cache_entry *ce,
1468                           struct unpack_trees_options *o)
1469{
1470        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1471                return 0;
1472        return verify_uptodate_1(ce, o, ERROR_NOT_UPTODATE_FILE);
1473}
1474
1475static int verify_uptodate_sparse(const struct cache_entry *ce,
1476                                  struct unpack_trees_options *o)
1477{
1478        return verify_uptodate_1(ce, o, ERROR_SPARSE_NOT_UPTODATE_FILE);
1479}
1480
1481static void invalidate_ce_path(const struct cache_entry *ce,
1482                               struct unpack_trees_options *o)
1483{
1484        if (!ce)
1485                return;
1486        cache_tree_invalidate_path(o->src_index, ce->name);
1487        untracked_cache_invalidate_path(o->src_index, ce->name);
1488}
1489
1490/*
1491 * Check that checking out ce->sha1 in subdir ce->name is not
1492 * going to overwrite any working files.
1493 *
1494 * Currently, git does not checkout subprojects during a superproject
1495 * checkout, so it is not going to overwrite anything.
1496 */
1497static int verify_clean_submodule(const char *old_sha1,
1498                                  const struct cache_entry *ce,
1499                                  enum unpack_trees_error_types error_type,
1500                                  struct unpack_trees_options *o)
1501{
1502        if (!submodule_from_ce(ce))
1503                return 0;
1504
1505        return check_submodule_move_head(ce, old_sha1,
1506                                         oid_to_hex(&ce->oid), o);
1507}
1508
1509static int verify_clean_subdirectory(const struct cache_entry *ce,
1510                                     enum unpack_trees_error_types error_type,
1511                                     struct unpack_trees_options *o)
1512{
1513        /*
1514         * we are about to extract "ce->name"; we would not want to lose
1515         * anything in the existing directory there.
1516         */
1517        int namelen;
1518        int i;
1519        struct dir_struct d;
1520        char *pathbuf;
1521        int cnt = 0;
1522
1523        if (S_ISGITLINK(ce->ce_mode)) {
1524                unsigned char sha1[20];
1525                int sub_head = resolve_gitlink_ref(ce->name, "HEAD", sha1);
1526                /*
1527                 * If we are not going to update the submodule, then
1528                 * we don't care.
1529                 */
1530                if (!sub_head && !hashcmp(sha1, ce->oid.hash))
1531                        return 0;
1532                return verify_clean_submodule(sub_head ? NULL : sha1_to_hex(sha1),
1533                                              ce, error_type, o);
1534        }
1535
1536        /*
1537         * First let's make sure we do not have a local modification
1538         * in that directory.
1539         */
1540        namelen = ce_namelen(ce);
1541        for (i = locate_in_src_index(ce, o);
1542             i < o->src_index->cache_nr;
1543             i++) {
1544                struct cache_entry *ce2 = o->src_index->cache[i];
1545                int len = ce_namelen(ce2);
1546                if (len < namelen ||
1547                    strncmp(ce->name, ce2->name, namelen) ||
1548                    ce2->name[namelen] != '/')
1549                        break;
1550                /*
1551                 * ce2->name is an entry in the subdirectory to be
1552                 * removed.
1553                 */
1554                if (!ce_stage(ce2)) {
1555                        if (verify_uptodate(ce2, o))
1556                                return -1;
1557                        add_entry(o, ce2, CE_REMOVE, 0);
1558                        mark_ce_used(ce2, o);
1559                }
1560                cnt++;
1561        }
1562
1563        /*
1564         * Then we need to make sure that we do not lose a locally
1565         * present file that is not ignored.
1566         */
1567        pathbuf = xstrfmt("%.*s/", namelen, ce->name);
1568
1569        memset(&d, 0, sizeof(d));
1570        if (o->dir)
1571                d.exclude_per_dir = o->dir->exclude_per_dir;
1572        i = read_directory(&d, pathbuf, namelen+1, NULL);
1573        if (i)
1574                return o->gently ? -1 :
1575                        add_rejected_path(o, ERROR_NOT_UPTODATE_DIR, ce->name);
1576        free(pathbuf);
1577        return cnt;
1578}
1579
1580/*
1581 * This gets called when there was no index entry for the tree entry 'dst',
1582 * but we found a file in the working tree that 'lstat()' said was fine,
1583 * and we're on a case-insensitive filesystem.
1584 *
1585 * See if we can find a case-insensitive match in the index that also
1586 * matches the stat information, and assume it's that other file!
1587 */
1588static int icase_exists(struct unpack_trees_options *o, const char *name, int len, struct stat *st)
1589{
1590        const struct cache_entry *src;
1591
1592        src = index_file_exists(o->src_index, name, len, 1);
1593        return src && !ie_match_stat(o->src_index, src, st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE);
1594}
1595
1596static int check_ok_to_remove(const char *name, int len, int dtype,
1597                              const struct cache_entry *ce, struct stat *st,
1598                              enum unpack_trees_error_types error_type,
1599                              struct unpack_trees_options *o)
1600{
1601        const struct cache_entry *result;
1602
1603        /*
1604         * It may be that the 'lstat()' succeeded even though
1605         * target 'ce' was absent, because there is an old
1606         * entry that is different only in case..
1607         *
1608         * Ignore that lstat() if it matches.
1609         */
1610        if (ignore_case && icase_exists(o, name, len, st))
1611                return 0;
1612
1613        if (o->dir &&
1614            is_excluded(o->dir, name, &dtype))
1615                /*
1616                 * ce->name is explicitly excluded, so it is Ok to
1617                 * overwrite it.
1618                 */
1619                return 0;
1620        if (S_ISDIR(st->st_mode)) {
1621                /*
1622                 * We are checking out path "foo" and
1623                 * found "foo/." in the working tree.
1624                 * This is tricky -- if we have modified
1625                 * files that are in "foo/" we would lose
1626                 * them.
1627                 */
1628                if (verify_clean_subdirectory(ce, error_type, o) < 0)
1629                        return -1;
1630                return 0;
1631        }
1632
1633        /*
1634         * The previous round may already have decided to
1635         * delete this path, which is in a subdirectory that
1636         * is being replaced with a blob.
1637         */
1638        result = index_file_exists(&o->result, name, len, 0);
1639        if (result) {
1640                if (result->ce_flags & CE_REMOVE)
1641                        return 0;
1642        }
1643
1644        return o->gently ? -1 :
1645                add_rejected_path(o, error_type, name);
1646}
1647
1648/*
1649 * We do not want to remove or overwrite a working tree file that
1650 * is not tracked, unless it is ignored.
1651 */
1652static int verify_absent_1(const struct cache_entry *ce,
1653                           enum unpack_trees_error_types error_type,
1654                           struct unpack_trees_options *o)
1655{
1656        int len;
1657        struct stat st;
1658
1659        if (o->index_only || o->reset || !o->update)
1660                return 0;
1661
1662        len = check_leading_path(ce->name, ce_namelen(ce));
1663        if (!len)
1664                return 0;
1665        else if (len > 0) {
1666                char *path;
1667                int ret;
1668
1669                path = xmemdupz(ce->name, len);
1670                if (lstat(path, &st))
1671                        ret = error_errno("cannot stat '%s'", path);
1672                else {
1673                        if (submodule_from_ce(ce))
1674                                ret = check_submodule_move_head(ce,
1675                                                                oid_to_hex(&ce->oid),
1676                                                                NULL, o);
1677                        else
1678                                ret = check_ok_to_remove(path, len, DT_UNKNOWN, NULL,
1679                                                         &st, error_type, o);
1680                }
1681                free(path);
1682                return ret;
1683        } else if (lstat(ce->name, &st)) {
1684                if (errno != ENOENT)
1685                        return error_errno("cannot stat '%s'", ce->name);
1686                return 0;
1687        } else {
1688                if (submodule_from_ce(ce))
1689                        return check_submodule_move_head(ce, oid_to_hex(&ce->oid),
1690                                                         NULL, o);
1691
1692                return check_ok_to_remove(ce->name, ce_namelen(ce),
1693                                          ce_to_dtype(ce), ce, &st,
1694                                          error_type, o);
1695        }
1696}
1697
1698static int verify_absent(const struct cache_entry *ce,
1699                         enum unpack_trees_error_types error_type,
1700                         struct unpack_trees_options *o)
1701{
1702        if (!o->skip_sparse_checkout && (ce->ce_flags & CE_NEW_SKIP_WORKTREE))
1703                return 0;
1704        return verify_absent_1(ce, error_type, o);
1705}
1706
1707static int verify_absent_sparse(const struct cache_entry *ce,
1708                                enum unpack_trees_error_types error_type,
1709                                struct unpack_trees_options *o)
1710{
1711        enum unpack_trees_error_types orphaned_error = error_type;
1712        if (orphaned_error == ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN)
1713                orphaned_error = ERROR_WOULD_LOSE_ORPHANED_OVERWRITTEN;
1714
1715        return verify_absent_1(ce, orphaned_error, o);
1716}
1717
1718static int merged_entry(const struct cache_entry *ce,
1719                        const struct cache_entry *old,
1720                        struct unpack_trees_options *o)
1721{
1722        int update = CE_UPDATE;
1723        struct cache_entry *merge = dup_entry(ce);
1724
1725        if (!old) {
1726                /*
1727                 * New index entries. In sparse checkout, the following
1728                 * verify_absent() will be delayed until after
1729                 * traverse_trees() finishes in unpack_trees(), then:
1730                 *
1731                 *  - CE_NEW_SKIP_WORKTREE will be computed correctly
1732                 *  - verify_absent() be called again, this time with
1733                 *    correct CE_NEW_SKIP_WORKTREE
1734                 *
1735                 * verify_absent() call here does nothing in sparse
1736                 * checkout (i.e. o->skip_sparse_checkout == 0)
1737                 */
1738                update |= CE_ADDED;
1739                merge->ce_flags |= CE_NEW_SKIP_WORKTREE;
1740
1741                if (verify_absent(merge,
1742                                  ERROR_WOULD_LOSE_UNTRACKED_OVERWRITTEN, o)) {
1743                        free(merge);
1744                        return -1;
1745                }
1746                invalidate_ce_path(merge, o);
1747
1748                if (submodule_from_ce(ce)) {
1749                        int ret = check_submodule_move_head(ce, NULL,
1750                                                            oid_to_hex(&ce->oid),
1751                                                            o);
1752                        if (ret)
1753                                return ret;
1754                }
1755
1756        } else if (!(old->ce_flags & CE_CONFLICTED)) {
1757                /*
1758                 * See if we can re-use the old CE directly?
1759                 * That way we get the uptodate stat info.
1760                 *
1761                 * This also removes the UPDATE flag on a match; otherwise
1762                 * we will end up overwriting local changes in the work tree.
1763                 */
1764                if (same(old, merge)) {
1765                        copy_cache_entry(merge, old);
1766                        update = 0;
1767                } else {
1768                        if (verify_uptodate(old, o)) {
1769                                free(merge);
1770                                return -1;
1771                        }
1772                        /* Migrate old flags over */
1773                        update |= old->ce_flags & (CE_SKIP_WORKTREE | CE_NEW_SKIP_WORKTREE);
1774                        invalidate_ce_path(old, o);
1775                }
1776
1777                if (submodule_from_ce(ce)) {
1778                        int ret = check_submodule_move_head(ce, oid_to_hex(&old->oid),
1779                                                            oid_to_hex(&ce->oid),
1780                                                            o);
1781                        if (ret)
1782                                return ret;
1783                }
1784        } else {
1785                /*
1786                 * Previously unmerged entry left as an existence
1787                 * marker by read_index_unmerged();
1788                 */
1789                invalidate_ce_path(old, o);
1790        }
1791
1792        do_add_entry(o, merge, update, CE_STAGEMASK);
1793        return 1;
1794}
1795
1796static int deleted_entry(const struct cache_entry *ce,
1797                         const struct cache_entry *old,
1798                         struct unpack_trees_options *o)
1799{
1800        /* Did it exist in the index? */
1801        if (!old) {
1802                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1803                        return -1;
1804                return 0;
1805        }
1806        if (!(old->ce_flags & CE_CONFLICTED) && verify_uptodate(old, o))
1807                return -1;
1808        add_entry(o, ce, CE_REMOVE, 0);
1809        invalidate_ce_path(ce, o);
1810        return 1;
1811}
1812
1813static int keep_entry(const struct cache_entry *ce,
1814                      struct unpack_trees_options *o)
1815{
1816        add_entry(o, ce, 0, 0);
1817        return 1;
1818}
1819
1820#if DBRT_DEBUG
1821static void show_stage_entry(FILE *o,
1822                             const char *label, const struct cache_entry *ce)
1823{
1824        if (!ce)
1825                fprintf(o, "%s (missing)\n", label);
1826        else
1827                fprintf(o, "%s%06o %s %d\t%s\n",
1828                        label,
1829                        ce->ce_mode,
1830                        oid_to_hex(&ce->oid),
1831                        ce_stage(ce),
1832                        ce->name);
1833}
1834#endif
1835
1836int threeway_merge(const struct cache_entry * const *stages,
1837                   struct unpack_trees_options *o)
1838{
1839        const struct cache_entry *index;
1840        const struct cache_entry *head;
1841        const struct cache_entry *remote = stages[o->head_idx + 1];
1842        int count;
1843        int head_match = 0;
1844        int remote_match = 0;
1845
1846        int df_conflict_head = 0;
1847        int df_conflict_remote = 0;
1848
1849        int any_anc_missing = 0;
1850        int no_anc_exists = 1;
1851        int i;
1852
1853        for (i = 1; i < o->head_idx; i++) {
1854                if (!stages[i] || stages[i] == o->df_conflict_entry)
1855                        any_anc_missing = 1;
1856                else
1857                        no_anc_exists = 0;
1858        }
1859
1860        index = stages[0];
1861        head = stages[o->head_idx];
1862
1863        if (head == o->df_conflict_entry) {
1864                df_conflict_head = 1;
1865                head = NULL;
1866        }
1867
1868        if (remote == o->df_conflict_entry) {
1869                df_conflict_remote = 1;
1870                remote = NULL;
1871        }
1872
1873        /*
1874         * First, if there's a #16 situation, note that to prevent #13
1875         * and #14.
1876         */
1877        if (!same(remote, head)) {
1878                for (i = 1; i < o->head_idx; i++) {
1879                        if (same(stages[i], head)) {
1880                                head_match = i;
1881                        }
1882                        if (same(stages[i], remote)) {
1883                                remote_match = i;
1884                        }
1885                }
1886        }
1887
1888        /*
1889         * We start with cases where the index is allowed to match
1890         * something other than the head: #14(ALT) and #2ALT, where it
1891         * is permitted to match the result instead.
1892         */
1893        /* #14, #14ALT, #2ALT */
1894        if (remote && !df_conflict_head && head_match && !remote_match) {
1895                if (index && !same(index, remote) && !same(index, head))
1896                        return reject_merge(index, o);
1897                return merged_entry(remote, index, o);
1898        }
1899        /*
1900         * If we have an entry in the index cache, then we want to
1901         * make sure that it matches head.
1902         */
1903        if (index && !same(index, head))
1904                return reject_merge(index, o);
1905
1906        if (head) {
1907                /* #5ALT, #15 */
1908                if (same(head, remote))
1909                        return merged_entry(head, index, o);
1910                /* #13, #3ALT */
1911                if (!df_conflict_remote && remote_match && !head_match)
1912                        return merged_entry(head, index, o);
1913        }
1914
1915        /* #1 */
1916        if (!head && !remote && any_anc_missing)
1917                return 0;
1918
1919        /*
1920         * Under the "aggressive" rule, we resolve mostly trivial
1921         * cases that we historically had git-merge-one-file resolve.
1922         */
1923        if (o->aggressive) {
1924                int head_deleted = !head;
1925                int remote_deleted = !remote;
1926                const struct cache_entry *ce = NULL;
1927
1928                if (index)
1929                        ce = index;
1930                else if (head)
1931                        ce = head;
1932                else if (remote)
1933                        ce = remote;
1934                else {
1935                        for (i = 1; i < o->head_idx; i++) {
1936                                if (stages[i] && stages[i] != o->df_conflict_entry) {
1937                                        ce = stages[i];
1938                                        break;
1939                                }
1940                        }
1941                }
1942
1943                /*
1944                 * Deleted in both.
1945                 * Deleted in one and unchanged in the other.
1946                 */
1947                if ((head_deleted && remote_deleted) ||
1948                    (head_deleted && remote && remote_match) ||
1949                    (remote_deleted && head && head_match)) {
1950                        if (index)
1951                                return deleted_entry(index, index, o);
1952                        if (ce && !head_deleted) {
1953                                if (verify_absent(ce, ERROR_WOULD_LOSE_UNTRACKED_REMOVED, o))
1954                                        return -1;
1955                        }
1956                        return 0;
1957                }
1958                /*
1959                 * Added in both, identically.
1960                 */
1961                if (no_anc_exists && head && remote && same(head, remote))
1962                        return merged_entry(head, index, o);
1963
1964        }
1965
1966        /* Below are "no merge" cases, which require that the index be
1967         * up-to-date to avoid the files getting overwritten with
1968         * conflict resolution files.
1969         */
1970        if (index) {
1971                if (verify_uptodate(index, o))
1972                        return -1;
1973        }
1974
1975        o->nontrivial_merge = 1;
1976
1977        /* #2, #3, #4, #6, #7, #9, #10, #11. */
1978        count = 0;
1979        if (!head_match || !remote_match) {
1980                for (i = 1; i < o->head_idx; i++) {
1981                        if (stages[i] && stages[i] != o->df_conflict_entry) {
1982                                keep_entry(stages[i], o);
1983                                count++;
1984                                break;
1985                        }
1986                }
1987        }
1988#if DBRT_DEBUG
1989        else {
1990                fprintf(stderr, "read-tree: warning #16 detected\n");
1991                show_stage_entry(stderr, "head   ", stages[head_match]);
1992                show_stage_entry(stderr, "remote ", stages[remote_match]);
1993        }
1994#endif
1995        if (head) { count += keep_entry(head, o); }
1996        if (remote) { count += keep_entry(remote, o); }
1997        return count;
1998}
1999
2000/*
2001 * Two-way merge.
2002 *
2003 * The rule is to "carry forward" what is in the index without losing
2004 * information across a "fast-forward", favoring a successful merge
2005 * over a merge failure when it makes sense.  For details of the
2006 * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
2007 *
2008 */
2009int twoway_merge(const struct cache_entry * const *src,
2010                 struct unpack_trees_options *o)
2011{
2012        const struct cache_entry *current = src[0];
2013        const struct cache_entry *oldtree = src[1];
2014        const struct cache_entry *newtree = src[2];
2015
2016        if (o->merge_size != 2)
2017                return error("Cannot do a twoway merge of %d trees",
2018                             o->merge_size);
2019
2020        if (oldtree == o->df_conflict_entry)
2021                oldtree = NULL;
2022        if (newtree == o->df_conflict_entry)
2023                newtree = NULL;
2024
2025        if (current) {
2026                if (current->ce_flags & CE_CONFLICTED) {
2027                        if (same(oldtree, newtree) || o->reset) {
2028                                if (!newtree)
2029                                        return deleted_entry(current, current, o);
2030                                else
2031                                        return merged_entry(newtree, current, o);
2032                        }
2033                        return reject_merge(current, o);
2034                } else if ((!oldtree && !newtree) || /* 4 and 5 */
2035                         (!oldtree && newtree &&
2036                          same(current, newtree)) || /* 6 and 7 */
2037                         (oldtree && newtree &&
2038                          same(oldtree, newtree)) || /* 14 and 15 */
2039                         (oldtree && newtree &&
2040                          !same(oldtree, newtree) && /* 18 and 19 */
2041                          same(current, newtree))) {
2042                        return keep_entry(current, o);
2043                } else if (oldtree && !newtree && same(current, oldtree)) {
2044                        /* 10 or 11 */
2045                        return deleted_entry(oldtree, current, o);
2046                } else if (oldtree && newtree &&
2047                         same(current, oldtree) && !same(current, newtree)) {
2048                        /* 20 or 21 */
2049                        return merged_entry(newtree, current, o);
2050                } else
2051                        return reject_merge(current, o);
2052        }
2053        else if (newtree) {
2054                if (oldtree && !o->initial_checkout) {
2055                        /*
2056                         * deletion of the path was staged;
2057                         */
2058                        if (same(oldtree, newtree))
2059                                return 1;
2060                        return reject_merge(oldtree, o);
2061                }
2062                return merged_entry(newtree, current, o);
2063        }
2064        return deleted_entry(oldtree, current, o);
2065}
2066
2067/*
2068 * Bind merge.
2069 *
2070 * Keep the index entries at stage0, collapse stage1 but make sure
2071 * stage0 does not have anything there.
2072 */
2073int bind_merge(const struct cache_entry * const *src,
2074               struct unpack_trees_options *o)
2075{
2076        const struct cache_entry *old = src[0];
2077        const struct cache_entry *a = src[1];
2078
2079        if (o->merge_size != 1)
2080                return error("Cannot do a bind merge of %d trees",
2081                             o->merge_size);
2082        if (a && old)
2083                return o->gently ? -1 :
2084                        error(ERRORMSG(o, ERROR_BIND_OVERLAP),
2085                              super_prefixed(a->name),
2086                              super_prefixed(old->name));
2087        if (!a)
2088                return keep_entry(old, o);
2089        else
2090                return merged_entry(a, NULL, o);
2091}
2092
2093/*
2094 * One-way merge.
2095 *
2096 * The rule is:
2097 * - take the stat information from stage0, take the data from stage1
2098 */
2099int oneway_merge(const struct cache_entry * const *src,
2100                 struct unpack_trees_options *o)
2101{
2102        const struct cache_entry *old = src[0];
2103        const struct cache_entry *a = src[1];
2104
2105        if (o->merge_size != 1)
2106                return error("Cannot do a oneway merge of %d trees",
2107                             o->merge_size);
2108
2109        if (!a || a == o->df_conflict_entry)
2110                return deleted_entry(old, old, o);
2111
2112        if (old && same(old, a)) {
2113                int update = 0;
2114                if (o->reset && o->update && !ce_uptodate(old) && !ce_skip_worktree(old)) {
2115                        struct stat st;
2116                        if (lstat(old->name, &st) ||
2117                            ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID|CE_MATCH_IGNORE_SKIP_WORKTREE))
2118                                update |= CE_UPDATE;
2119                }
2120                add_entry(o, old, update, 0);
2121                return 0;
2122        }
2123        return merged_entry(a, old, o);
2124}