diff-lib.con commit DESTDIR support for git/contrib/emacs (1e31fbe)
   1/*
   2 * Copyright (C) 2005 Junio C Hamano
   3 */
   4#include "cache.h"
   5#include "quote.h"
   6#include "commit.h"
   7#include "diff.h"
   8#include "diffcore.h"
   9#include "revision.h"
  10#include "cache-tree.h"
  11#include "path-list.h"
  12
  13/*
  14 * diff-files
  15 */
  16
  17static int read_directory(const char *path, struct path_list *list)
  18{
  19        DIR *dir;
  20        struct dirent *e;
  21
  22        if (!(dir = opendir(path)))
  23                return error("Could not open directory %s", path);
  24
  25        while ((e = readdir(dir)))
  26                if (strcmp(".", e->d_name) && strcmp("..", e->d_name))
  27                        path_list_insert(xstrdup(e->d_name), list);
  28
  29        closedir(dir);
  30        return 0;
  31}
  32
  33static int get_mode(const char *path, int *mode)
  34{
  35        struct stat st;
  36
  37        if (!path || !strcmp(path, "/dev/null"))
  38                *mode = 0;
  39        else if (!strcmp(path, "-"))
  40                *mode = ntohl(create_ce_mode(0666));
  41        else if (stat(path, &st))
  42                return error("Could not access '%s'", path);
  43        else
  44                *mode = st.st_mode;
  45        return 0;
  46}
  47
  48static int queue_diff(struct diff_options *o,
  49                const char *name1, const char *name2)
  50{
  51        int mode1 = 0, mode2 = 0;
  52
  53        if (get_mode(name1, &mode1) || get_mode(name2, &mode2))
  54                return -1;
  55
  56        if (mode1 && mode2 && S_ISDIR(mode1) != S_ISDIR(mode2))
  57                return error("file/directory conflict: %s, %s", name1, name2);
  58
  59        if (S_ISDIR(mode1) || S_ISDIR(mode2)) {
  60                char buffer1[PATH_MAX], buffer2[PATH_MAX];
  61                struct path_list p1 = {NULL, 0, 0, 1}, p2 = {NULL, 0, 0, 1};
  62                int len1 = 0, len2 = 0, i1, i2, ret = 0;
  63
  64                if (name1 && read_directory(name1, &p1))
  65                        return -1;
  66                if (name2 && read_directory(name2, &p2)) {
  67                        path_list_clear(&p1, 0);
  68                        return -1;
  69                }
  70
  71                if (name1) {
  72                        len1 = strlen(name1);
  73                        if (len1 > 0 && name1[len1 - 1] == '/')
  74                                len1--;
  75                        memcpy(buffer1, name1, len1);
  76                        buffer1[len1++] = '/';
  77                }
  78
  79                if (name2) {
  80                        len2 = strlen(name2);
  81                        if (len2 > 0 && name2[len2 - 1] == '/')
  82                                len2--;
  83                        memcpy(buffer2, name2, len2);
  84                        buffer2[len2++] = '/';
  85                }
  86
  87                for (i1 = i2 = 0; !ret && (i1 < p1.nr || i2 < p2.nr); ) {
  88                        const char *n1, *n2;
  89                        int comp;
  90
  91                        if (i1 == p1.nr)
  92                                comp = 1;
  93                        else if (i2 == p2.nr)
  94                                comp = -1;
  95                        else
  96                                comp = strcmp(p1.items[i1].path,
  97                                        p2.items[i2].path);
  98
  99                        if (comp > 0)
 100                                n1 = NULL;
 101                        else {
 102                                n1 = buffer1;
 103                                strncpy(buffer1 + len1, p1.items[i1++].path,
 104                                                PATH_MAX - len1);
 105                        }
 106
 107                        if (comp < 0)
 108                                n2 = NULL;
 109                        else {
 110                                n2 = buffer2;
 111                                strncpy(buffer2 + len2, p2.items[i2++].path,
 112                                                PATH_MAX - len2);
 113                        }
 114
 115                        ret = queue_diff(o, n1, n2);
 116                }
 117                path_list_clear(&p1, 0);
 118                path_list_clear(&p2, 0);
 119
 120                return ret;
 121        } else {
 122                struct diff_filespec *d1, *d2;
 123
 124                if (o->reverse_diff) {
 125                        unsigned tmp;
 126                        const char *tmp_c;
 127                        tmp = mode1; mode1 = mode2; mode2 = tmp;
 128                        tmp_c = name1; name1 = name2; name2 = tmp_c;
 129                }
 130
 131                if (!name1)
 132                        name1 = "/dev/null";
 133                if (!name2)
 134                        name2 = "/dev/null";
 135                d1 = alloc_filespec(name1);
 136                d2 = alloc_filespec(name2);
 137                fill_filespec(d1, null_sha1, mode1);
 138                fill_filespec(d2, null_sha1, mode2);
 139
 140                diff_queue(&diff_queued_diff, d1, d2);
 141                return 0;
 142        }
 143}
 144
 145static int is_in_index(const char *path)
 146{
 147        int len = strlen(path);
 148        int pos = cache_name_pos(path, len);
 149        char c;
 150
 151        if (pos < 0)
 152                return 0;
 153        if (strncmp(active_cache[pos]->name, path, len))
 154                return 0;
 155        c = active_cache[pos]->name[len];
 156        return c == '\0' || c == '/';
 157}
 158
 159static int handle_diff_files_args(struct rev_info *revs,
 160                int argc, const char **argv, int *silent)
 161{
 162        *silent = 0;
 163
 164        /* revs->max_count == -2 means --no-index */
 165        while (1 < argc && argv[1][0] == '-') {
 166                if (!strcmp(argv[1], "--base"))
 167                        revs->max_count = 1;
 168                else if (!strcmp(argv[1], "--ours"))
 169                        revs->max_count = 2;
 170                else if (!strcmp(argv[1], "--theirs"))
 171                        revs->max_count = 3;
 172                else if (!strcmp(argv[1], "-n") ||
 173                                !strcmp(argv[1], "--no-index")) {
 174                        revs->max_count = -2;
 175                        revs->diffopt.exit_with_status = 1;
 176                }
 177                else if (!strcmp(argv[1], "-q"))
 178                        *silent = 1;
 179                else
 180                        return error("invalid option: %s", argv[1]);
 181                argv++; argc--;
 182        }
 183
 184        if (revs->max_count == -1 && revs->diffopt.nr_paths == 2) {
 185                /*
 186                 * If two files are specified, and at least one is untracked,
 187                 * default to no-index.
 188                 */
 189                read_cache();
 190                if (!is_in_index(revs->diffopt.paths[0]) ||
 191                                        !is_in_index(revs->diffopt.paths[1]))
 192                        revs->max_count = -2;
 193        }
 194
 195        /*
 196         * Make sure there are NO revision (i.e. pending object) parameter,
 197         * rev.max_count is reasonable (0 <= n <= 3),
 198         * there is no other revision filtering parameters.
 199         */
 200        if (revs->pending.nr || revs->max_count > 3 ||
 201            revs->min_age != -1 || revs->max_age != -1)
 202                return error("no revision allowed with diff-files");
 203
 204        if (revs->max_count == -1 &&
 205            (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 206                revs->combine_merges = revs->dense_combined_merges = 1;
 207
 208        return 0;
 209}
 210
 211static int is_outside_repo(const char *path, int nongit, const char *prefix)
 212{
 213        int i;
 214        if (nongit || !strcmp(path, "-") || path[0] == '/')
 215                return 1;
 216        if (prefixcmp(path, "../"))
 217                return 0;
 218        if (!prefix)
 219                return 1;
 220        for (i = strlen(prefix); !prefixcmp(path, "../"); ) {
 221                while (i > 0 && prefix[i - 1] != '/')
 222                        i--;
 223                if (--i < 0)
 224                        return 1;
 225                path += 3;
 226        }
 227        return 0;
 228}
 229
 230int setup_diff_no_index(struct rev_info *revs,
 231                int argc, const char ** argv, int nongit, const char *prefix)
 232{
 233        int i;
 234        for (i = 1; i < argc; i++)
 235                if (argv[i][0] != '-' || argv[i][1] == '\0')
 236                        break;
 237                else if (!strcmp(argv[i], "--")) {
 238                        i++;
 239                        break;
 240                } else if (i < argc - 3 && !strcmp(argv[i], "--no-index")) {
 241                        i = argc - 3;
 242                        revs->diffopt.exit_with_status = 1;
 243                        break;
 244                }
 245        if (argc != i + 2 || (!is_outside_repo(argv[i + 1], nongit, prefix) &&
 246                                !is_outside_repo(argv[i], nongit, prefix)))
 247                return -1;
 248
 249        diff_setup(&revs->diffopt);
 250        for (i = 1; i < argc - 2; )
 251                if (!strcmp(argv[i], "--no-index"))
 252                        i++;
 253                else {
 254                        int j = diff_opt_parse(&revs->diffopt,
 255                                        argv + i, argc - i);
 256                        if (!j)
 257                                die("invalid diff option/value: %s", argv[i]);
 258                        i += j;
 259                }
 260
 261        if (prefix) {
 262                int len = strlen(prefix);
 263
 264                revs->diffopt.paths = xcalloc(2, sizeof(char*));
 265                for (i = 0; i < 2; i++) {
 266                        const char *p = argv[argc - 2 + i];
 267                        /*
 268                         * stdin should be spelled as '-'; if you have
 269                         * path that is '-', spell it as ./-.
 270                         */
 271                        p = (strcmp(p, "-")
 272                             ? xstrdup(prefix_filename(prefix, len, p))
 273                             : p);
 274                        revs->diffopt.paths[i] = p;
 275                }
 276        }
 277        else
 278                revs->diffopt.paths = argv + argc - 2;
 279        revs->diffopt.nr_paths = 2;
 280        revs->max_count = -2;
 281        return 0;
 282}
 283
 284int run_diff_files_cmd(struct rev_info *revs, int argc, const char **argv)
 285{
 286        int silent_on_removed;
 287
 288        if (handle_diff_files_args(revs, argc, argv, &silent_on_removed))
 289                return -1;
 290
 291        if (revs->max_count == -2) {
 292                if (revs->diffopt.nr_paths != 2)
 293                        return error("need two files/directories with --no-index");
 294                if (queue_diff(&revs->diffopt, revs->diffopt.paths[0],
 295                                revs->diffopt.paths[1]))
 296                        return -1;
 297                diffcore_std(&revs->diffopt);
 298                diff_flush(&revs->diffopt);
 299                /*
 300                 * The return code for --no-index imitates diff(1):
 301                 * 0 = no changes, 1 = changes, else error
 302                 */
 303                return revs->diffopt.found_changes;
 304        }
 305
 306        if (read_cache() < 0) {
 307                perror("read_cache");
 308                return -1;
 309        }
 310        return run_diff_files(revs, silent_on_removed);
 311}
 312
 313int run_diff_files(struct rev_info *revs, int silent_on_removed)
 314{
 315        int entries, i;
 316        int diff_unmerged_stage = revs->max_count;
 317
 318        if (diff_unmerged_stage < 0)
 319                diff_unmerged_stage = 2;
 320        entries = active_nr;
 321        for (i = 0; i < entries; i++) {
 322                struct stat st;
 323                unsigned int oldmode, newmode;
 324                struct cache_entry *ce = active_cache[i];
 325                int changed;
 326
 327                if (revs->diffopt.quiet && revs->diffopt.has_changes)
 328                        break;
 329
 330                if (!ce_path_match(ce, revs->prune_data))
 331                        continue;
 332
 333                if (ce_stage(ce)) {
 334                        struct combine_diff_path *dpath;
 335                        int num_compare_stages = 0;
 336                        size_t path_len;
 337
 338                        path_len = ce_namelen(ce);
 339
 340                        dpath = xmalloc(combine_diff_path_size(5, path_len));
 341                        dpath->path = (char *) &(dpath->parent[5]);
 342
 343                        dpath->next = NULL;
 344                        dpath->len = path_len;
 345                        memcpy(dpath->path, ce->name, path_len);
 346                        dpath->path[path_len] = '\0';
 347                        hashclr(dpath->sha1);
 348                        memset(&(dpath->parent[0]), 0,
 349                               sizeof(struct combine_diff_parent)*5);
 350
 351                        if (lstat(ce->name, &st) < 0) {
 352                                if (errno != ENOENT && errno != ENOTDIR) {
 353                                        perror(ce->name);
 354                                        continue;
 355                                }
 356                                if (silent_on_removed)
 357                                        continue;
 358                        }
 359                        else
 360                                dpath->mode = canon_mode(st.st_mode);
 361
 362                        while (i < entries) {
 363                                struct cache_entry *nce = active_cache[i];
 364                                int stage;
 365
 366                                if (strcmp(ce->name, nce->name))
 367                                        break;
 368
 369                                /* Stage #2 (ours) is the first parent,
 370                                 * stage #3 (theirs) is the second.
 371                                 */
 372                                stage = ce_stage(nce);
 373                                if (2 <= stage) {
 374                                        int mode = ntohl(nce->ce_mode);
 375                                        num_compare_stages++;
 376                                        hashcpy(dpath->parent[stage-2].sha1, nce->sha1);
 377                                        dpath->parent[stage-2].mode =
 378                                                canon_mode(mode);
 379                                        dpath->parent[stage-2].status =
 380                                                DIFF_STATUS_MODIFIED;
 381                                }
 382
 383                                /* diff against the proper unmerged stage */
 384                                if (stage == diff_unmerged_stage)
 385                                        ce = nce;
 386                                i++;
 387                        }
 388                        /*
 389                         * Compensate for loop update
 390                         */
 391                        i--;
 392
 393                        if (revs->combine_merges && num_compare_stages == 2) {
 394                                show_combined_diff(dpath, 2,
 395                                                   revs->dense_combined_merges,
 396                                                   revs);
 397                                free(dpath);
 398                                continue;
 399                        }
 400                        free(dpath);
 401                        dpath = NULL;
 402
 403                        /*
 404                         * Show the diff for the 'ce' if we found the one
 405                         * from the desired stage.
 406                         */
 407                        diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
 408                        if (ce_stage(ce) != diff_unmerged_stage)
 409                                continue;
 410                }
 411
 412                if (lstat(ce->name, &st) < 0) {
 413                        if (errno != ENOENT && errno != ENOTDIR) {
 414                                perror(ce->name);
 415                                continue;
 416                        }
 417                        if (silent_on_removed)
 418                                continue;
 419                        diff_addremove(&revs->diffopt, '-', ntohl(ce->ce_mode),
 420                                       ce->sha1, ce->name, NULL);
 421                        continue;
 422                }
 423                changed = ce_match_stat(ce, &st, 0);
 424                if (!changed && !revs->diffopt.find_copies_harder)
 425                        continue;
 426                oldmode = ntohl(ce->ce_mode);
 427
 428                newmode = canon_mode(st.st_mode);
 429                if (!trust_executable_bit &&
 430                    S_ISREG(newmode) && S_ISREG(oldmode) &&
 431                    ((newmode ^ oldmode) == 0111))
 432                        newmode = oldmode;
 433                else if (!has_symlinks &&
 434                    S_ISREG(newmode) && S_ISLNK(oldmode))
 435                        newmode = oldmode;
 436                diff_change(&revs->diffopt, oldmode, newmode,
 437                            ce->sha1, (changed ? null_sha1 : ce->sha1),
 438                            ce->name, NULL);
 439
 440        }
 441        diffcore_std(&revs->diffopt);
 442        diff_flush(&revs->diffopt);
 443        return 0;
 444}
 445
 446/*
 447 * diff-index
 448 */
 449
 450/* A file entry went away or appeared */
 451static void diff_index_show_file(struct rev_info *revs,
 452                                 const char *prefix,
 453                                 struct cache_entry *ce,
 454                                 unsigned char *sha1, unsigned int mode)
 455{
 456        diff_addremove(&revs->diffopt, prefix[0], ntohl(mode),
 457                       sha1, ce->name, NULL);
 458}
 459
 460static int get_stat_data(struct cache_entry *ce,
 461                         unsigned char **sha1p,
 462                         unsigned int *modep,
 463                         int cached, int match_missing)
 464{
 465        unsigned char *sha1 = ce->sha1;
 466        unsigned int mode = ce->ce_mode;
 467
 468        if (!cached) {
 469                static unsigned char no_sha1[20];
 470                int changed;
 471                struct stat st;
 472                if (lstat(ce->name, &st) < 0) {
 473                        if (errno == ENOENT && match_missing) {
 474                                *sha1p = sha1;
 475                                *modep = mode;
 476                                return 0;
 477                        }
 478                        return -1;
 479                }
 480                changed = ce_match_stat(ce, &st, 0);
 481                if (changed) {
 482                        mode = ce_mode_from_stat(ce, st.st_mode);
 483                        sha1 = no_sha1;
 484                }
 485        }
 486
 487        *sha1p = sha1;
 488        *modep = mode;
 489        return 0;
 490}
 491
 492static void show_new_file(struct rev_info *revs,
 493                          struct cache_entry *new,
 494                          int cached, int match_missing)
 495{
 496        unsigned char *sha1;
 497        unsigned int mode;
 498
 499        /* New file in the index: it might actually be different in
 500         * the working copy.
 501         */
 502        if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0)
 503                return;
 504
 505        diff_index_show_file(revs, "+", new, sha1, mode);
 506}
 507
 508static int show_modified(struct rev_info *revs,
 509                         struct cache_entry *old,
 510                         struct cache_entry *new,
 511                         int report_missing,
 512                         int cached, int match_missing)
 513{
 514        unsigned int mode, oldmode;
 515        unsigned char *sha1;
 516
 517        if (get_stat_data(new, &sha1, &mode, cached, match_missing) < 0) {
 518                if (report_missing)
 519                        diff_index_show_file(revs, "-", old,
 520                                             old->sha1, old->ce_mode);
 521                return -1;
 522        }
 523
 524        if (revs->combine_merges && !cached &&
 525            (hashcmp(sha1, old->sha1) || hashcmp(old->sha1, new->sha1))) {
 526                struct combine_diff_path *p;
 527                int pathlen = ce_namelen(new);
 528
 529                p = xmalloc(combine_diff_path_size(2, pathlen));
 530                p->path = (char *) &p->parent[2];
 531                p->next = NULL;
 532                p->len = pathlen;
 533                memcpy(p->path, new->name, pathlen);
 534                p->path[pathlen] = 0;
 535                p->mode = ntohl(mode);
 536                hashclr(p->sha1);
 537                memset(p->parent, 0, 2 * sizeof(struct combine_diff_parent));
 538                p->parent[0].status = DIFF_STATUS_MODIFIED;
 539                p->parent[0].mode = ntohl(new->ce_mode);
 540                hashcpy(p->parent[0].sha1, new->sha1);
 541                p->parent[1].status = DIFF_STATUS_MODIFIED;
 542                p->parent[1].mode = ntohl(old->ce_mode);
 543                hashcpy(p->parent[1].sha1, old->sha1);
 544                show_combined_diff(p, 2, revs->dense_combined_merges, revs);
 545                free(p);
 546                return 0;
 547        }
 548
 549        oldmode = old->ce_mode;
 550        if (mode == oldmode && !hashcmp(sha1, old->sha1) &&
 551            !revs->diffopt.find_copies_harder)
 552                return 0;
 553
 554        mode = ntohl(mode);
 555        oldmode = ntohl(oldmode);
 556
 557        diff_change(&revs->diffopt, oldmode, mode,
 558                    old->sha1, sha1, old->name, NULL);
 559        return 0;
 560}
 561
 562static int diff_cache(struct rev_info *revs,
 563                      struct cache_entry **ac, int entries,
 564                      const char **pathspec,
 565                      int cached, int match_missing)
 566{
 567        while (entries) {
 568                struct cache_entry *ce = *ac;
 569                int same = (entries > 1) && ce_same_name(ce, ac[1]);
 570
 571                if (revs->diffopt.quiet && revs->diffopt.has_changes)
 572                        break;
 573
 574                if (!ce_path_match(ce, pathspec))
 575                        goto skip_entry;
 576
 577                switch (ce_stage(ce)) {
 578                case 0:
 579                        /* No stage 1 entry? That means it's a new file */
 580                        if (!same) {
 581                                show_new_file(revs, ce, cached, match_missing);
 582                                break;
 583                        }
 584                        /* Show difference between old and new */
 585                        show_modified(revs, ac[1], ce, 1,
 586                                      cached, match_missing);
 587                        break;
 588                case 1:
 589                        /* No stage 3 (merge) entry?
 590                         * That means it's been deleted.
 591                         */
 592                        if (!same) {
 593                                diff_index_show_file(revs, "-", ce,
 594                                                     ce->sha1, ce->ce_mode);
 595                                break;
 596                        }
 597                        /* We come here with ce pointing at stage 1
 598                         * (original tree) and ac[1] pointing at stage
 599                         * 3 (unmerged).  show-modified with
 600                         * report-missing set to false does not say the
 601                         * file is deleted but reports true if work
 602                         * tree does not have it, in which case we
 603                         * fall through to report the unmerged state.
 604                         * Otherwise, we show the differences between
 605                         * the original tree and the work tree.
 606                         */
 607                        if (!cached &&
 608                            !show_modified(revs, ce, ac[1], 0,
 609                                           cached, match_missing))
 610                                break;
 611                        diff_unmerge(&revs->diffopt, ce->name,
 612                                     ntohl(ce->ce_mode), ce->sha1);
 613                        break;
 614                case 3:
 615                        diff_unmerge(&revs->diffopt, ce->name,
 616                                     0, null_sha1);
 617                        break;
 618
 619                default:
 620                        die("impossible cache entry stage");
 621                }
 622
 623skip_entry:
 624                /*
 625                 * Ignore all the different stages for this file,
 626                 * we've handled the relevant cases now.
 627                 */
 628                do {
 629                        ac++;
 630                        entries--;
 631                } while (entries && ce_same_name(ce, ac[0]));
 632        }
 633        return 0;
 634}
 635
 636/*
 637 * This turns all merge entries into "stage 3". That guarantees that
 638 * when we read in the new tree (into "stage 1"), we won't lose sight
 639 * of the fact that we had unmerged entries.
 640 */
 641static void mark_merge_entries(void)
 642{
 643        int i;
 644        for (i = 0; i < active_nr; i++) {
 645                struct cache_entry *ce = active_cache[i];
 646                if (!ce_stage(ce))
 647                        continue;
 648                ce->ce_flags |= htons(CE_STAGEMASK);
 649        }
 650}
 651
 652int run_diff_index(struct rev_info *revs, int cached)
 653{
 654        int ret;
 655        struct object *ent;
 656        struct tree *tree;
 657        const char *tree_name;
 658        int match_missing = 0;
 659
 660        /* 
 661         * Backward compatibility wart - "diff-index -m" does
 662         * not mean "do not ignore merges", but totally different.
 663         */
 664        if (!revs->ignore_merges)
 665                match_missing = 1;
 666
 667        mark_merge_entries();
 668
 669        ent = revs->pending.objects[0].item;
 670        tree_name = revs->pending.objects[0].name;
 671        tree = parse_tree_indirect(ent->sha1);
 672        if (!tree)
 673                return error("bad tree object %s", tree_name);
 674        if (read_tree(tree, 1, revs->prune_data))
 675                return error("unable to read tree object %s", tree_name);
 676        ret = diff_cache(revs, active_cache, active_nr, revs->prune_data,
 677                         cached, match_missing);
 678        diffcore_std(&revs->diffopt);
 679        diff_flush(&revs->diffopt);
 680        return ret;
 681}
 682
 683int do_diff_cache(const unsigned char *tree_sha1, struct diff_options *opt)
 684{
 685        struct tree *tree;
 686        struct rev_info revs;
 687        int i;
 688        struct cache_entry **dst;
 689        struct cache_entry *last = NULL;
 690
 691        /*
 692         * This is used by git-blame to run diff-cache internally;
 693         * it potentially needs to repeatedly run this, so we will
 694         * start by removing the higher order entries the last round
 695         * left behind.
 696         */
 697        dst = active_cache;
 698        for (i = 0; i < active_nr; i++) {
 699                struct cache_entry *ce = active_cache[i];
 700                if (ce_stage(ce)) {
 701                        if (last && !strcmp(ce->name, last->name))
 702                                continue;
 703                        cache_tree_invalidate_path(active_cache_tree,
 704                                                   ce->name);
 705                        last = ce;
 706                        ce->ce_mode = 0;
 707                        ce->ce_flags &= ~htons(CE_STAGEMASK);
 708                }
 709                *dst++ = ce;
 710        }
 711        active_nr = dst - active_cache;
 712
 713        init_revisions(&revs, NULL);
 714        revs.prune_data = opt->paths;
 715        tree = parse_tree_indirect(tree_sha1);
 716        if (!tree)
 717                die("bad tree object %s", sha1_to_hex(tree_sha1));
 718        if (read_tree(tree, 1, opt->paths))
 719                return error("unable to read tree %s", sha1_to_hex(tree_sha1));
 720        return diff_cache(&revs, active_cache, active_nr, revs.prune_data,
 721                          1, 0);
 722}