Andrew's git / gitweb.git / attr.c
?
attr.con commit Merge branch 'jc/index-update-if-able' into maint (44ec754)
   1#define NO_THE_INDEX_COMPATIBILITY_MACROS
   2#include "cache.h"
   3#include "exec_cmd.h"
   4#include "attr.h"
   5
   6const char git_attr__true[] = "(builtin)true";
   7const char git_attr__false[] = "\0(builtin)false";
   8static const char git_attr__unknown[] = "(builtin)unknown";
   9#define ATTR__TRUE git_attr__true
  10#define ATTR__FALSE git_attr__false
  11#define ATTR__UNSET NULL
  12#define ATTR__UNKNOWN git_attr__unknown
  13
  14static const char *attributes_file;
  15
  16/*
  17 * The basic design decision here is that we are not going to have
  18 * insanely large number of attributes.
  19 *
  20 * This is a randomly chosen prime.
  21 */
  22#define HASHSIZE 257
  23
  24#ifndef DEBUG_ATTR
  25#define DEBUG_ATTR 0
  26#endif
  27
  28struct git_attr {
  29        struct git_attr *next;
  30        unsigned h;
  31        int attr_nr;
  32        char name[FLEX_ARRAY];
  33};
  34static int attr_nr;
  35
  36static struct git_attr_check *check_all_attr;
  37static struct git_attr *(git_attr_hash[HASHSIZE]);
  38
  39static unsigned hash_name(const char *name, int namelen)
  40{
  41        unsigned val = 0, c;
  42
  43        while (namelen--) {
  44                c = *name++;
  45                val = ((val << 7) | (val >> 22)) ^ c;
  46        }
  47        return val;
  48}
  49
  50static int invalid_attr_name(const char *name, int namelen)
  51{
  52        /*
  53         * Attribute name cannot begin with '-' and from
  54         * [-A-Za-z0-9_.].  We'd specifically exclude '=' for now,
  55         * as we might later want to allow non-binary value for
  56         * attributes, e.g. "*.svg      merge=special-merge-program-for-svg"
  57         */
  58        if (*name == '-')
  59                return -1;
  60        while (namelen--) {
  61                char ch = *name++;
  62                if (! (ch == '-' || ch == '.' || ch == '_' ||
  63                       ('0' <= ch && ch <= '9') ||
  64                       ('a' <= ch && ch <= 'z') ||
  65                       ('A' <= ch && ch <= 'Z')) )
  66                        return -1;
  67        }
  68        return 0;
  69}
  70
  71static struct git_attr *git_attr_internal(const char *name, int len)
  72{
  73        unsigned hval = hash_name(name, len);
  74        unsigned pos = hval % HASHSIZE;
  75        struct git_attr *a;
  76
  77        for (a = git_attr_hash[pos]; a; a = a->next) {
  78                if (a->h == hval &&
  79                    !memcmp(a->name, name, len) && !a->name[len])
  80                        return a;
  81        }
  82
  83        if (invalid_attr_name(name, len))
  84                return NULL;
  85
  86        a = xmalloc(sizeof(*a) + len + 1);
  87        memcpy(a->name, name, len);
  88        a->name[len] = 0;
  89        a->h = hval;
  90        a->next = git_attr_hash[pos];
  91        a->attr_nr = attr_nr++;
  92        git_attr_hash[pos] = a;
  93
  94        check_all_attr = xrealloc(check_all_attr,
  95                                  sizeof(*check_all_attr) * attr_nr);
  96        check_all_attr[a->attr_nr].attr = a;
  97        check_all_attr[a->attr_nr].value = ATTR__UNKNOWN;
  98        return a;
  99}
 100
 101struct git_attr *git_attr(const char *name)
 102{
 103        return git_attr_internal(name, strlen(name));
 104}
 105
 106/*
 107 * .gitattributes file is one line per record, each of which is
 108 *
 109 * (1) glob pattern.
 110 * (2) whitespace
 111 * (3) whitespace separated list of attribute names, each of which
 112 *     could be prefixed with '-' to mean "set to false", '!' to mean
 113 *     "unset".
 114 */
 115
 116/* What does a matched pattern decide? */
 117struct attr_state {
 118        struct git_attr *attr;
 119        const char *setto;
 120};
 121
 122struct match_attr {
 123        union {
 124                char *pattern;
 125                struct git_attr *attr;
 126        } u;
 127        char is_macro;
 128        unsigned num_attr;
 129        struct attr_state state[FLEX_ARRAY];
 130};
 131
 132static const char blank[] = " \t\r\n";
 133
 134static const char *parse_attr(const char *src, int lineno, const char *cp,
 135                              int *num_attr, struct match_attr *res)
 136{
 137        const char *ep, *equals;
 138        int len;
 139
 140        ep = cp + strcspn(cp, blank);
 141        equals = strchr(cp, '=');
 142        if (equals && ep < equals)
 143                equals = NULL;
 144        if (equals)
 145                len = equals - cp;
 146        else
 147                len = ep - cp;
 148        if (!res) {
 149                if (*cp == '-' || *cp == '!') {
 150                        cp++;
 151                        len--;
 152                }
 153                if (invalid_attr_name(cp, len)) {
 154                        fprintf(stderr,
 155                                "%.*s is not a valid attribute name: %s:%d\n",
 156                                len, cp, src, lineno);
 157                        return NULL;
 158                }
 159        } else {
 160                struct attr_state *e;
 161
 162                e = &(res->state[*num_attr]);
 163                if (*cp == '-' || *cp == '!') {
 164                        e->setto = (*cp == '-') ? ATTR__FALSE : ATTR__UNSET;
 165                        cp++;
 166                        len--;
 167                }
 168                else if (!equals)
 169                        e->setto = ATTR__TRUE;
 170                else {
 171                        e->setto = xmemdupz(equals + 1, ep - equals - 1);
 172                }
 173                e->attr = git_attr_internal(cp, len);
 174        }
 175        (*num_attr)++;
 176        return ep + strspn(ep, blank);
 177}
 178
 179static struct match_attr *parse_attr_line(const char *line, const char *src,
 180                                          int lineno, int macro_ok)
 181{
 182        int namelen;
 183        int num_attr;
 184        const char *cp, *name;
 185        struct match_attr *res = NULL;
 186        int pass;
 187        int is_macro;
 188
 189        cp = line + strspn(line, blank);
 190        if (!*cp || *cp == '#')
 191                return NULL;
 192        name = cp;
 193        namelen = strcspn(name, blank);
 194        if (strlen(ATTRIBUTE_MACRO_PREFIX) < namelen &&
 195            !prefixcmp(name, ATTRIBUTE_MACRO_PREFIX)) {
 196                if (!macro_ok) {
 197                        fprintf(stderr, "%s not allowed: %s:%d\n",
 198                                name, src, lineno);
 199                        return NULL;
 200                }
 201                is_macro = 1;
 202                name += strlen(ATTRIBUTE_MACRO_PREFIX);
 203                name += strspn(name, blank);
 204                namelen = strcspn(name, blank);
 205                if (invalid_attr_name(name, namelen)) {
 206                        fprintf(stderr,
 207                                "%.*s is not a valid attribute name: %s:%d\n",
 208                                namelen, name, src, lineno);
 209                        return NULL;
 210                }
 211        }
 212        else
 213                is_macro = 0;
 214
 215        for (pass = 0; pass < 2; pass++) {
 216                /* pass 0 counts and allocates, pass 1 fills */
 217                num_attr = 0;
 218                cp = name + namelen;
 219                cp = cp + strspn(cp, blank);
 220                while (*cp) {
 221                        cp = parse_attr(src, lineno, cp, &num_attr, res);
 222                        if (!cp)
 223                                return NULL;
 224                }
 225                if (pass)
 226                        break;
 227                res = xcalloc(1,
 228                              sizeof(*res) +
 229                              sizeof(struct attr_state) * num_attr +
 230                              (is_macro ? 0 : namelen + 1));
 231                if (is_macro)
 232                        res->u.attr = git_attr_internal(name, namelen);
 233                else {
 234                        res->u.pattern = (char *)&(res->state[num_attr]);
 235                        memcpy(res->u.pattern, name, namelen);
 236                        res->u.pattern[namelen] = 0;
 237                }
 238                res->is_macro = is_macro;
 239                res->num_attr = num_attr;
 240        }
 241        return res;
 242}
 243
 244/*
 245 * Like info/exclude and .gitignore, the attribute information can
 246 * come from many places.
 247 *
 248 * (1) .gitattribute file of the same directory;
 249 * (2) .gitattribute file of the parent directory if (1) does not have
 250 *      any match; this goes recursively upwards, just like .gitignore.
 251 * (3) $GIT_DIR/info/attributes, which overrides both of the above.
 252 *
 253 * In the same file, later entries override the earlier match, so in the
 254 * global list, we would have entries from info/attributes the earliest
 255 * (reading the file from top to bottom), .gitattribute of the root
 256 * directory (again, reading the file from top to bottom) down to the
 257 * current directory, and then scan the list backwards to find the first match.
 258 * This is exactly the same as what excluded() does in dir.c to deal with
 259 * .gitignore
 260 */
 261
 262static struct attr_stack {
 263        struct attr_stack *prev;
 264        char *origin;
 265        unsigned num_matches;
 266        unsigned alloc;
 267        struct match_attr **attrs;
 268} *attr_stack;
 269
 270static void free_attr_elem(struct attr_stack *e)
 271{
 272        int i;
 273        free(e->origin);
 274        for (i = 0; i < e->num_matches; i++) {
 275                struct match_attr *a = e->attrs[i];
 276                int j;
 277                for (j = 0; j < a->num_attr; j++) {
 278                        const char *setto = a->state[j].setto;
 279                        if (setto == ATTR__TRUE ||
 280                            setto == ATTR__FALSE ||
 281                            setto == ATTR__UNSET ||
 282                            setto == ATTR__UNKNOWN)
 283                                ;
 284                        else
 285                                free((char *) setto);
 286                }
 287                free(a);
 288        }
 289        free(e);
 290}
 291
 292static const char *builtin_attr[] = {
 293        "[attr]binary -diff -text",
 294        NULL,
 295};
 296
 297static void handle_attr_line(struct attr_stack *res,
 298                             const char *line,
 299                             const char *src,
 300                             int lineno,
 301                             int macro_ok)
 302{
 303        struct match_attr *a;
 304
 305        a = parse_attr_line(line, src, lineno, macro_ok);
 306        if (!a)
 307                return;
 308        if (res->alloc <= res->num_matches) {
 309                res->alloc = alloc_nr(res->num_matches);
 310                res->attrs = xrealloc(res->attrs,
 311                                      sizeof(struct match_attr *) *
 312                                      res->alloc);
 313        }
 314        res->attrs[res->num_matches++] = a;
 315}
 316
 317static struct attr_stack *read_attr_from_array(const char **list)
 318{
 319        struct attr_stack *res;
 320        const char *line;
 321        int lineno = 0;
 322
 323        res = xcalloc(1, sizeof(*res));
 324        while ((line = *(list++)) != NULL)
 325                handle_attr_line(res, line, "[builtin]", ++lineno, 1);
 326        return res;
 327}
 328
 329static enum git_attr_direction direction;
 330static struct index_state *use_index;
 331
 332static struct attr_stack *read_attr_from_file(const char *path, int macro_ok)
 333{
 334        FILE *fp = fopen(path, "r");
 335        struct attr_stack *res;
 336        char buf[2048];
 337        int lineno = 0;
 338
 339        if (!fp)
 340                return NULL;
 341        res = xcalloc(1, sizeof(*res));
 342        while (fgets(buf, sizeof(buf), fp))
 343                handle_attr_line(res, buf, path, ++lineno, macro_ok);
 344        fclose(fp);
 345        return res;
 346}
 347
 348static void *read_index_data(const char *path)
 349{
 350        int pos, len;
 351        unsigned long sz;
 352        enum object_type type;
 353        void *data;
 354        struct index_state *istate = use_index ? use_index : &the_index;
 355
 356        len = strlen(path);
 357        pos = index_name_pos(istate, path, len);
 358        if (pos < 0) {
 359                /*
 360                 * We might be in the middle of a merge, in which
 361                 * case we would read stage #2 (ours).
 362                 */
 363                int i;
 364                for (i = -pos - 1;
 365                     (pos < 0 && i < istate->cache_nr &&
 366                      !strcmp(istate->cache[i]->name, path));
 367                     i++)
 368                        if (ce_stage(istate->cache[i]) == 2)
 369                                pos = i;
 370        }
 371        if (pos < 0)
 372                return NULL;
 373        data = read_sha1_file(istate->cache[pos]->sha1, &type, &sz);
 374        if (!data || type != OBJ_BLOB) {
 375                free(data);
 376                return NULL;
 377        }
 378        return data;
 379}
 380
 381static struct attr_stack *read_attr_from_index(const char *path, int macro_ok)
 382{
 383        struct attr_stack *res;
 384        char *buf, *sp;
 385        int lineno = 0;
 386
 387        buf = read_index_data(path);
 388        if (!buf)
 389                return NULL;
 390
 391        res = xcalloc(1, sizeof(*res));
 392        for (sp = buf; *sp; ) {
 393                char *ep;
 394                int more;
 395                for (ep = sp; *ep && *ep != '\n'; ep++)
 396                        ;
 397                more = (*ep == '\n');
 398                *ep = '\0';
 399                handle_attr_line(res, sp, path, ++lineno, macro_ok);
 400                sp = ep + more;
 401        }
 402        free(buf);
 403        return res;
 404}
 405
 406static struct attr_stack *read_attr(const char *path, int macro_ok)
 407{
 408        struct attr_stack *res;
 409
 410        if (direction == GIT_ATTR_CHECKOUT) {
 411                res = read_attr_from_index(path, macro_ok);
 412                if (!res)
 413                        res = read_attr_from_file(path, macro_ok);
 414        }
 415        else if (direction == GIT_ATTR_CHECKIN) {
 416                res = read_attr_from_file(path, macro_ok);
 417                if (!res)
 418                        /*
 419                         * There is no checked out .gitattributes file there, but
 420                         * we might have it in the index.  We allow operation in a
 421                         * sparsely checked out work tree, so read from it.
 422                         */
 423                        res = read_attr_from_index(path, macro_ok);
 424        }
 425        else
 426                res = read_attr_from_index(path, macro_ok);
 427        if (!res)
 428                res = xcalloc(1, sizeof(*res));
 429        return res;
 430}
 431
 432#if DEBUG_ATTR
 433static void debug_info(const char *what, struct attr_stack *elem)
 434{
 435        fprintf(stderr, "%s: %s\n", what, elem->origin ? elem->origin : "()");
 436}
 437static void debug_set(const char *what, const char *match, struct git_attr *attr, const void *v)
 438{
 439        const char *value = v;
 440
 441        if (ATTR_TRUE(value))
 442                value = "set";
 443        else if (ATTR_FALSE(value))
 444                value = "unset";
 445        else if (ATTR_UNSET(value))
 446                value = "unspecified";
 447
 448        fprintf(stderr, "%s: %s => %s (%s)\n",
 449                what, attr->name, (char *) value, match);
 450}
 451#define debug_push(a) debug_info("push", (a))
 452#define debug_pop(a) debug_info("pop", (a))
 453#else
 454#define debug_push(a) do { ; } while (0)
 455#define debug_pop(a) do { ; } while (0)
 456#define debug_set(a,b,c,d) do { ; } while (0)
 457#endif
 458
 459static void drop_attr_stack(void)
 460{
 461        while (attr_stack) {
 462                struct attr_stack *elem = attr_stack;
 463                attr_stack = elem->prev;
 464                free_attr_elem(elem);
 465        }
 466}
 467
 468const char *git_etc_gitattributes(void)
 469{
 470        static const char *system_wide;
 471        if (!system_wide)
 472                system_wide = system_path(ETC_GITATTRIBUTES);
 473        return system_wide;
 474}
 475
 476int git_attr_system(void)
 477{
 478        return !git_env_bool("GIT_ATTR_NOSYSTEM", 0);
 479}
 480
 481int git_attr_global(void)
 482{
 483        return !git_env_bool("GIT_ATTR_NOGLOBAL", 0);
 484}
 485
 486static int git_attr_config(const char *var, const char *value, void *dummy)
 487{
 488        if (!strcmp(var, "core.attributesfile"))
 489                return git_config_pathname(&attributes_file, var, value);
 490
 491        return 0;
 492}
 493
 494static void bootstrap_attr_stack(void)
 495{
 496        if (!attr_stack) {
 497                struct attr_stack *elem;
 498
 499                elem = read_attr_from_array(builtin_attr);
 500                elem->origin = NULL;
 501                elem->prev = attr_stack;
 502                attr_stack = elem;
 503
 504                if (git_attr_system()) {
 505                        elem = read_attr_from_file(git_etc_gitattributes(), 1);
 506                        if (elem) {
 507                                elem->origin = NULL;
 508                                elem->prev = attr_stack;
 509                                attr_stack = elem;
 510                        }
 511                }
 512
 513                git_config(git_attr_config, NULL);
 514                if (git_attr_global() && attributes_file) {
 515                        elem = read_attr_from_file(attributes_file, 1);
 516                        if (elem) {
 517                                elem->origin = NULL;
 518                                elem->prev = attr_stack;
 519                                attr_stack = elem;
 520                        }
 521                }
 522
 523                if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 524                        elem = read_attr(GITATTRIBUTES_FILE, 1);
 525                        elem->origin = strdup("");
 526                        elem->prev = attr_stack;
 527                        attr_stack = elem;
 528                        debug_push(elem);
 529                }
 530
 531                elem = read_attr_from_file(git_path(INFOATTRIBUTES_FILE), 1);
 532                if (!elem)
 533                        elem = xcalloc(1, sizeof(*elem));
 534                elem->origin = NULL;
 535                elem->prev = attr_stack;
 536                attr_stack = elem;
 537        }
 538}
 539
 540static void prepare_attr_stack(const char *path, int dirlen)
 541{
 542        struct attr_stack *elem, *info;
 543        int len;
 544        struct strbuf pathbuf;
 545
 546        strbuf_init(&pathbuf, dirlen+2+strlen(GITATTRIBUTES_FILE));
 547
 548        /*
 549         * At the bottom of the attribute stack is the built-in
 550         * set of attribute definitions, followed by the contents
 551         * of $(prefix)/etc/gitattributes and a file specified by
 552         * core.attributesfile.  Then, contents from
 553         * .gitattribute files from directories closer to the
 554         * root to the ones in deeper directories are pushed
 555         * to the stack.  Finally, at the very top of the stack
 556         * we always keep the contents of $GIT_DIR/info/attributes.
 557         *
 558         * When checking, we use entries from near the top of the
 559         * stack, preferring $GIT_DIR/info/attributes, then
 560         * .gitattributes in deeper directories to shallower ones,
 561         * and finally use the built-in set as the default.
 562         */
 563        if (!attr_stack)
 564                bootstrap_attr_stack();
 565
 566        /*
 567         * Pop the "info" one that is always at the top of the stack.
 568         */
 569        info = attr_stack;
 570        attr_stack = info->prev;
 571
 572        /*
 573         * Pop the ones from directories that are not the prefix of
 574         * the path we are checking.
 575         */
 576        while (attr_stack && attr_stack->origin) {
 577                int namelen = strlen(attr_stack->origin);
 578
 579                elem = attr_stack;
 580                if (namelen <= dirlen &&
 581                    !strncmp(elem->origin, path, namelen))
 582                        break;
 583
 584                debug_pop(elem);
 585                attr_stack = elem->prev;
 586                free_attr_elem(elem);
 587        }
 588
 589        /*
 590         * Read from parent directories and push them down
 591         */
 592        if (!is_bare_repository() || direction == GIT_ATTR_INDEX) {
 593                while (1) {
 594                        char *cp;
 595
 596                        len = strlen(attr_stack->origin);
 597                        if (dirlen <= len)
 598                                break;
 599                        strbuf_reset(&pathbuf);
 600                        strbuf_add(&pathbuf, path, dirlen);
 601                        strbuf_addch(&pathbuf, '/');
 602                        cp = strchr(pathbuf.buf + len + 1, '/');
 603                        strcpy(cp + 1, GITATTRIBUTES_FILE);
 604                        elem = read_attr(pathbuf.buf, 0);
 605                        *cp = '\0';
 606                        elem->origin = strdup(pathbuf.buf);
 607                        elem->prev = attr_stack;
 608                        attr_stack = elem;
 609                        debug_push(elem);
 610                }
 611        }
 612
 613        strbuf_release(&pathbuf);
 614
 615        /*
 616         * Finally push the "info" one at the top of the stack.
 617         */
 618        info->prev = attr_stack;
 619        attr_stack = info;
 620}
 621
 622static int path_matches(const char *pathname, int pathlen,
 623                        const char *pattern,
 624                        const char *base, int baselen)
 625{
 626        if (!strchr(pattern, '/')) {
 627                /* match basename */
 628                const char *basename = strrchr(pathname, '/');
 629                basename = basename ? basename + 1 : pathname;
 630                return (fnmatch(pattern, basename, 0) == 0);
 631        }
 632        /*
 633         * match with FNM_PATHNAME; the pattern has base implicitly
 634         * in front of it.
 635         */
 636        if (*pattern == '/')
 637                pattern++;
 638        if (pathlen < baselen ||
 639            (baselen && pathname[baselen] != '/') ||
 640            strncmp(pathname, base, baselen))
 641                return 0;
 642        if (baselen != 0)
 643                baselen++;
 644        return fnmatch(pattern, pathname + baselen, FNM_PATHNAME) == 0;
 645}
 646
 647static int macroexpand_one(int attr_nr, int rem);
 648
 649static int fill_one(const char *what, struct match_attr *a, int rem)
 650{
 651        struct git_attr_check *check = check_all_attr;
 652        int i;
 653
 654        for (i = a->num_attr - 1; 0 < rem && 0 <= i; i--) {
 655                struct git_attr *attr = a->state[i].attr;
 656                const char **n = &(check[attr->attr_nr].value);
 657                const char *v = a->state[i].setto;
 658
 659                if (*n == ATTR__UNKNOWN) {
 660                        debug_set(what,
 661                                  a->is_macro ? a->u.attr->name : a->u.pattern,
 662                                  attr, v);
 663                        *n = v;
 664                        rem--;
 665                        rem = macroexpand_one(attr->attr_nr, rem);
 666                }
 667        }
 668        return rem;
 669}
 670
 671static int fill(const char *path, int pathlen, struct attr_stack *stk, int rem)
 672{
 673        int i;
 674        const char *base = stk->origin ? stk->origin : "";
 675
 676        for (i = stk->num_matches - 1; 0 < rem && 0 <= i; i--) {
 677                struct match_attr *a = stk->attrs[i];
 678                if (a->is_macro)
 679                        continue;
 680                if (path_matches(path, pathlen,
 681                                 a->u.pattern, base, strlen(base)))
 682                        rem = fill_one("fill", a, rem);
 683        }
 684        return rem;
 685}
 686
 687static int macroexpand_one(int attr_nr, int rem)
 688{
 689        struct attr_stack *stk;
 690        struct match_attr *a = NULL;
 691        int i;
 692
 693        if (check_all_attr[attr_nr].value != ATTR__TRUE)
 694                return rem;
 695
 696        for (stk = attr_stack; !a && stk; stk = stk->prev)
 697                for (i = stk->num_matches - 1; !a && 0 <= i; i--) {
 698                        struct match_attr *ma = stk->attrs[i];
 699                        if (!ma->is_macro)
 700                                continue;
 701                        if (ma->u.attr->attr_nr == attr_nr)
 702                                a = ma;
 703                }
 704
 705        if (a)
 706                rem = fill_one("expand", a, rem);
 707
 708        return rem;
 709}
 710
 711int git_checkattr(const char *path, int num, struct git_attr_check *check)
 712{
 713        struct attr_stack *stk;
 714        const char *cp;
 715        int dirlen, pathlen, i, rem;
 716
 717        bootstrap_attr_stack();
 718        for (i = 0; i < attr_nr; i++)
 719                check_all_attr[i].value = ATTR__UNKNOWN;
 720
 721        pathlen = strlen(path);
 722        cp = strrchr(path, '/');
 723        if (!cp)
 724                dirlen = 0;
 725        else
 726                dirlen = cp - path;
 727        prepare_attr_stack(path, dirlen);
 728        rem = attr_nr;
 729        for (stk = attr_stack; 0 < rem && stk; stk = stk->prev)
 730                rem = fill(path, pathlen, stk, rem);
 731
 732        for (i = 0; i < num; i++) {
 733                const char *value = check_all_attr[check[i].attr->attr_nr].value;
 734                if (value == ATTR__UNKNOWN)
 735                        value = ATTR__UNSET;
 736                check[i].value = value;
 737        }
 738
 739        return 0;
 740}
 741
 742void git_attr_set_direction(enum git_attr_direction new, struct index_state *istate)
 743{
 744        enum git_attr_direction old = direction;
 745
 746        if (is_bare_repository() && new != GIT_ATTR_INDEX)
 747                die("BUG: non-INDEX attr direction in a bare repo");
 748
 749        direction = new;
 750        if (new != old)
 751                drop_attr_stack();
 752        use_index = istate;
 753}