bisect.con commit bisect--helper: remove "--next-vars" option as it is now useless (c99f069)
   1#include "cache.h"
   2#include "commit.h"
   3#include "diff.h"
   4#include "revision.h"
   5#include "refs.h"
   6#include "list-objects.h"
   7#include "quote.h"
   8#include "sha1-lookup.h"
   9#include "run-command.h"
  10#include "bisect.h"
  11
  12static unsigned char (*skipped_sha1)[20];
  13static int skipped_sha1_nr;
  14static int skipped_sha1_alloc;
  15
  16static const char **rev_argv;
  17static int rev_argv_nr;
  18static int rev_argv_alloc;
  19
  20static const unsigned char *current_bad_sha1;
  21
  22static const char *argv_diff_tree[] = {"diff-tree", "--pretty", NULL, NULL};
  23static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
  24static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
  25
  26/* bits #0-15 in revision.h */
  27
  28#define COUNTED         (1u<<16)
  29
  30/*
  31 * This is a truly stupid algorithm, but it's only
  32 * used for bisection, and we just don't care enough.
  33 *
  34 * We care just barely enough to avoid recursing for
  35 * non-merge entries.
  36 */
  37static int count_distance(struct commit_list *entry)
  38{
  39        int nr = 0;
  40
  41        while (entry) {
  42                struct commit *commit = entry->item;
  43                struct commit_list *p;
  44
  45                if (commit->object.flags & (UNINTERESTING | COUNTED))
  46                        break;
  47                if (!(commit->object.flags & TREESAME))
  48                        nr++;
  49                commit->object.flags |= COUNTED;
  50                p = commit->parents;
  51                entry = p;
  52                if (p) {
  53                        p = p->next;
  54                        while (p) {
  55                                nr += count_distance(p);
  56                                p = p->next;
  57                        }
  58                }
  59        }
  60
  61        return nr;
  62}
  63
  64static void clear_distance(struct commit_list *list)
  65{
  66        while (list) {
  67                struct commit *commit = list->item;
  68                commit->object.flags &= ~COUNTED;
  69                list = list->next;
  70        }
  71}
  72
  73#define DEBUG_BISECT 0
  74
  75static inline int weight(struct commit_list *elem)
  76{
  77        return *((int*)(elem->item->util));
  78}
  79
  80static inline void weight_set(struct commit_list *elem, int weight)
  81{
  82        *((int*)(elem->item->util)) = weight;
  83}
  84
  85static int count_interesting_parents(struct commit *commit)
  86{
  87        struct commit_list *p;
  88        int count;
  89
  90        for (count = 0, p = commit->parents; p; p = p->next) {
  91                if (p->item->object.flags & UNINTERESTING)
  92                        continue;
  93                count++;
  94        }
  95        return count;
  96}
  97
  98static inline int halfway(struct commit_list *p, int nr)
  99{
 100        /*
 101         * Don't short-cut something we are not going to return!
 102         */
 103        if (p->item->object.flags & TREESAME)
 104                return 0;
 105        if (DEBUG_BISECT)
 106                return 0;
 107        /*
 108         * 2 and 3 are halfway of 5.
 109         * 3 is halfway of 6 but 2 and 4 are not.
 110         */
 111        switch (2 * weight(p) - nr) {
 112        case -1: case 0: case 1:
 113                return 1;
 114        default:
 115                return 0;
 116        }
 117}
 118
 119#if !DEBUG_BISECT
 120#define show_list(a,b,c,d) do { ; } while (0)
 121#else
 122static void show_list(const char *debug, int counted, int nr,
 123                      struct commit_list *list)
 124{
 125        struct commit_list *p;
 126
 127        fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
 128
 129        for (p = list; p; p = p->next) {
 130                struct commit_list *pp;
 131                struct commit *commit = p->item;
 132                unsigned flags = commit->object.flags;
 133                enum object_type type;
 134                unsigned long size;
 135                char *buf = read_sha1_file(commit->object.sha1, &type, &size);
 136                char *ep, *sp;
 137
 138                fprintf(stderr, "%c%c%c ",
 139                        (flags & TREESAME) ? ' ' : 'T',
 140                        (flags & UNINTERESTING) ? 'U' : ' ',
 141                        (flags & COUNTED) ? 'C' : ' ');
 142                if (commit->util)
 143                        fprintf(stderr, "%3d", weight(p));
 144                else
 145                        fprintf(stderr, "---");
 146                fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
 147                for (pp = commit->parents; pp; pp = pp->next)
 148                        fprintf(stderr, " %.*s", 8,
 149                                sha1_to_hex(pp->item->object.sha1));
 150
 151                sp = strstr(buf, "\n\n");
 152                if (sp) {
 153                        sp += 2;
 154                        for (ep = sp; *ep && *ep != '\n'; ep++)
 155                                ;
 156                        fprintf(stderr, " %.*s", (int)(ep - sp), sp);
 157                }
 158                fprintf(stderr, "\n");
 159        }
 160}
 161#endif /* DEBUG_BISECT */
 162
 163static struct commit_list *best_bisection(struct commit_list *list, int nr)
 164{
 165        struct commit_list *p, *best;
 166        int best_distance = -1;
 167
 168        best = list;
 169        for (p = list; p; p = p->next) {
 170                int distance;
 171                unsigned flags = p->item->object.flags;
 172
 173                if (flags & TREESAME)
 174                        continue;
 175                distance = weight(p);
 176                if (nr - distance < distance)
 177                        distance = nr - distance;
 178                if (distance > best_distance) {
 179                        best = p;
 180                        best_distance = distance;
 181                }
 182        }
 183
 184        return best;
 185}
 186
 187struct commit_dist {
 188        struct commit *commit;
 189        int distance;
 190};
 191
 192static int compare_commit_dist(const void *a_, const void *b_)
 193{
 194        struct commit_dist *a, *b;
 195
 196        a = (struct commit_dist *)a_;
 197        b = (struct commit_dist *)b_;
 198        if (a->distance != b->distance)
 199                return b->distance - a->distance; /* desc sort */
 200        return hashcmp(a->commit->object.sha1, b->commit->object.sha1);
 201}
 202
 203static struct commit_list *best_bisection_sorted(struct commit_list *list, int nr)
 204{
 205        struct commit_list *p;
 206        struct commit_dist *array = xcalloc(nr, sizeof(*array));
 207        int cnt, i;
 208
 209        for (p = list, cnt = 0; p; p = p->next) {
 210                int distance;
 211                unsigned flags = p->item->object.flags;
 212
 213                if (flags & TREESAME)
 214                        continue;
 215                distance = weight(p);
 216                if (nr - distance < distance)
 217                        distance = nr - distance;
 218                array[cnt].commit = p->item;
 219                array[cnt].distance = distance;
 220                cnt++;
 221        }
 222        qsort(array, cnt, sizeof(*array), compare_commit_dist);
 223        for (p = list, i = 0; i < cnt; i++) {
 224                struct name_decoration *r = xmalloc(sizeof(*r) + 100);
 225                struct object *obj = &(array[i].commit->object);
 226
 227                sprintf(r->name, "dist=%d", array[i].distance);
 228                r->next = add_decoration(&name_decoration, obj, r);
 229                p->item = array[i].commit;
 230                p = p->next;
 231        }
 232        if (p)
 233                p->next = NULL;
 234        free(array);
 235        return list;
 236}
 237
 238/*
 239 * zero or positive weight is the number of interesting commits it can
 240 * reach, including itself.  Especially, weight = 0 means it does not
 241 * reach any tree-changing commits (e.g. just above uninteresting one
 242 * but traversal is with pathspec).
 243 *
 244 * weight = -1 means it has one parent and its distance is yet to
 245 * be computed.
 246 *
 247 * weight = -2 means it has more than one parent and its distance is
 248 * unknown.  After running count_distance() first, they will get zero
 249 * or positive distance.
 250 */
 251static struct commit_list *do_find_bisection(struct commit_list *list,
 252                                             int nr, int *weights,
 253                                             int find_all)
 254{
 255        int n, counted;
 256        struct commit_list *p;
 257
 258        counted = 0;
 259
 260        for (n = 0, p = list; p; p = p->next) {
 261                struct commit *commit = p->item;
 262                unsigned flags = commit->object.flags;
 263
 264                p->item->util = &weights[n++];
 265                switch (count_interesting_parents(commit)) {
 266                case 0:
 267                        if (!(flags & TREESAME)) {
 268                                weight_set(p, 1);
 269                                counted++;
 270                                show_list("bisection 2 count one",
 271                                          counted, nr, list);
 272                        }
 273                        /*
 274                         * otherwise, it is known not to reach any
 275                         * tree-changing commit and gets weight 0.
 276                         */
 277                        break;
 278                case 1:
 279                        weight_set(p, -1);
 280                        break;
 281                default:
 282                        weight_set(p, -2);
 283                        break;
 284                }
 285        }
 286
 287        show_list("bisection 2 initialize", counted, nr, list);
 288
 289        /*
 290         * If you have only one parent in the resulting set
 291         * then you can reach one commit more than that parent
 292         * can reach.  So we do not have to run the expensive
 293         * count_distance() for single strand of pearls.
 294         *
 295         * However, if you have more than one parents, you cannot
 296         * just add their distance and one for yourself, since
 297         * they usually reach the same ancestor and you would
 298         * end up counting them twice that way.
 299         *
 300         * So we will first count distance of merges the usual
 301         * way, and then fill the blanks using cheaper algorithm.
 302         */
 303        for (p = list; p; p = p->next) {
 304                if (p->item->object.flags & UNINTERESTING)
 305                        continue;
 306                if (weight(p) != -2)
 307                        continue;
 308                weight_set(p, count_distance(p));
 309                clear_distance(list);
 310
 311                /* Does it happen to be at exactly half-way? */
 312                if (!find_all && halfway(p, nr))
 313                        return p;
 314                counted++;
 315        }
 316
 317        show_list("bisection 2 count_distance", counted, nr, list);
 318
 319        while (counted < nr) {
 320                for (p = list; p; p = p->next) {
 321                        struct commit_list *q;
 322                        unsigned flags = p->item->object.flags;
 323
 324                        if (0 <= weight(p))
 325                                continue;
 326                        for (q = p->item->parents; q; q = q->next) {
 327                                if (q->item->object.flags & UNINTERESTING)
 328                                        continue;
 329                                if (0 <= weight(q))
 330                                        break;
 331                        }
 332                        if (!q)
 333                                continue;
 334
 335                        /*
 336                         * weight for p is unknown but q is known.
 337                         * add one for p itself if p is to be counted,
 338                         * otherwise inherit it from q directly.
 339                         */
 340                        if (!(flags & TREESAME)) {
 341                                weight_set(p, weight(q)+1);
 342                                counted++;
 343                                show_list("bisection 2 count one",
 344                                          counted, nr, list);
 345                        }
 346                        else
 347                                weight_set(p, weight(q));
 348
 349                        /* Does it happen to be at exactly half-way? */
 350                        if (!find_all && halfway(p, nr))
 351                                return p;
 352                }
 353        }
 354
 355        show_list("bisection 2 counted all", counted, nr, list);
 356
 357        if (!find_all)
 358                return best_bisection(list, nr);
 359        else
 360                return best_bisection_sorted(list, nr);
 361}
 362
 363struct commit_list *find_bisection(struct commit_list *list,
 364                                          int *reaches, int *all,
 365                                          int find_all)
 366{
 367        int nr, on_list;
 368        struct commit_list *p, *best, *next, *last;
 369        int *weights;
 370
 371        show_list("bisection 2 entry", 0, 0, list);
 372
 373        /*
 374         * Count the number of total and tree-changing items on the
 375         * list, while reversing the list.
 376         */
 377        for (nr = on_list = 0, last = NULL, p = list;
 378             p;
 379             p = next) {
 380                unsigned flags = p->item->object.flags;
 381
 382                next = p->next;
 383                if (flags & UNINTERESTING)
 384                        continue;
 385                p->next = last;
 386                last = p;
 387                if (!(flags & TREESAME))
 388                        nr++;
 389                on_list++;
 390        }
 391        list = last;
 392        show_list("bisection 2 sorted", 0, nr, list);
 393
 394        *all = nr;
 395        weights = xcalloc(on_list, sizeof(*weights));
 396
 397        /* Do the real work of finding bisection commit. */
 398        best = do_find_bisection(list, nr, weights, find_all);
 399        if (best) {
 400                if (!find_all)
 401                        best->next = NULL;
 402                *reaches = weight(best);
 403        }
 404        free(weights);
 405        return best;
 406}
 407
 408static int register_ref(const char *refname, const unsigned char *sha1,
 409                        int flags, void *cb_data)
 410{
 411        if (!strcmp(refname, "bad")) {
 412                ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
 413                current_bad_sha1 = sha1;
 414                rev_argv[rev_argv_nr++] = xstrdup(sha1_to_hex(sha1));
 415        } else if (!prefixcmp(refname, "good-")) {
 416                const char *hex = sha1_to_hex(sha1);
 417                char *good = xmalloc(strlen(hex) + 2);
 418                *good = '^';
 419                memcpy(good + 1, hex, strlen(hex) + 1);
 420                ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
 421                rev_argv[rev_argv_nr++] = good;
 422        } else if (!prefixcmp(refname, "skip-")) {
 423                ALLOC_GROW(skipped_sha1, skipped_sha1_nr + 1,
 424                           skipped_sha1_alloc);
 425                hashcpy(skipped_sha1[skipped_sha1_nr++], sha1);
 426        }
 427
 428        return 0;
 429}
 430
 431static int read_bisect_refs(void)
 432{
 433        return for_each_ref_in("refs/bisect/", register_ref, NULL);
 434}
 435
 436void read_bisect_paths(void)
 437{
 438        struct strbuf str = STRBUF_INIT;
 439        const char *filename = git_path("BISECT_NAMES");
 440        FILE *fp = fopen(filename, "r");
 441
 442        if (!fp)
 443                die("Could not open file '%s': %s", filename, strerror(errno));
 444
 445        while (strbuf_getline(&str, fp, '\n') != EOF) {
 446                char *quoted;
 447                int res;
 448
 449                strbuf_trim(&str);
 450                quoted = strbuf_detach(&str, NULL);
 451                res = sq_dequote_to_argv(quoted, &rev_argv,
 452                                         &rev_argv_nr, &rev_argv_alloc);
 453                if (res)
 454                        die("Badly quoted content in file '%s': %s",
 455                            filename, quoted);
 456        }
 457
 458        strbuf_release(&str);
 459        fclose(fp);
 460}
 461
 462static int skipcmp(const void *a, const void *b)
 463{
 464        return hashcmp(a, b);
 465}
 466
 467static void prepare_skipped(void)
 468{
 469        qsort(skipped_sha1, skipped_sha1_nr, sizeof(*skipped_sha1), skipcmp);
 470}
 471
 472static const unsigned char *skipped_sha1_access(size_t index, void *table)
 473{
 474        unsigned char (*skipped)[20] = table;
 475        return skipped[index];
 476}
 477
 478static int lookup_skipped(unsigned char *sha1)
 479{
 480        return sha1_pos(sha1, skipped_sha1, skipped_sha1_nr,
 481                        skipped_sha1_access);
 482}
 483
 484struct commit_list *filter_skipped(struct commit_list *list,
 485                                   struct commit_list **tried,
 486                                   int show_all)
 487{
 488        struct commit_list *filtered = NULL, **f = &filtered;
 489
 490        *tried = NULL;
 491
 492        if (!skipped_sha1_nr)
 493                return list;
 494
 495        prepare_skipped();
 496
 497        while (list) {
 498                struct commit_list *next = list->next;
 499                list->next = NULL;
 500                if (0 <= lookup_skipped(list->item->object.sha1)) {
 501                        /* Move current to tried list */
 502                        *tried = list;
 503                        tried = &list->next;
 504                } else {
 505                        if (!show_all)
 506                                return list;
 507                        /* Move current to filtered list */
 508                        *f = list;
 509                        f = &list->next;
 510                }
 511                list = next;
 512        }
 513
 514        return filtered;
 515}
 516
 517static void bisect_rev_setup(struct rev_info *revs, const char *prefix)
 518{
 519        init_revisions(revs, prefix);
 520        revs->abbrev = 0;
 521        revs->commit_format = CMIT_FMT_UNSPECIFIED;
 522
 523        /* argv[0] will be ignored by setup_revisions */
 524        ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
 525        rev_argv[rev_argv_nr++] = xstrdup("bisect_rev_setup");
 526
 527        if (read_bisect_refs())
 528                die("reading bisect refs failed");
 529
 530        ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
 531        rev_argv[rev_argv_nr++] = xstrdup("--");
 532
 533        read_bisect_paths();
 534
 535        ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
 536        rev_argv[rev_argv_nr++] = NULL;
 537
 538        setup_revisions(rev_argv_nr, rev_argv, revs, NULL);
 539
 540        revs->limited = 1;
 541}
 542
 543static void bisect_common(struct rev_info *revs, const char *prefix,
 544                          int *reaches, int *all)
 545{
 546        bisect_rev_setup(revs, prefix);
 547
 548        if (prepare_revision_walk(revs))
 549                die("revision walk setup failed");
 550        if (revs->tree_objects)
 551                mark_edges_uninteresting(revs->commits, revs, NULL);
 552
 553        revs->commits = find_bisection(revs->commits, reaches, all,
 554                                       !!skipped_sha1_nr);
 555}
 556
 557static void exit_if_skipped_commits(struct commit_list *tried,
 558                                    const unsigned char *bad)
 559{
 560        if (!tried)
 561                return;
 562
 563        printf("There are only 'skip'ped commits left to test.\n"
 564               "The first bad commit could be any of:\n");
 565        print_commit_list(tried, "%s\n", "%s\n");
 566        if (bad)
 567                printf("%s\n", sha1_to_hex(bad));
 568        printf("We cannot bisect more!\n");
 569        exit(2);
 570}
 571
 572static void mark_expected_rev(char *bisect_rev_hex)
 573{
 574        int len = strlen(bisect_rev_hex);
 575        const char *filename = git_path("BISECT_EXPECTED_REV");
 576        int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
 577
 578        if (fd < 0)
 579                die("could not create file '%s': %s",
 580                    filename, strerror(errno));
 581
 582        bisect_rev_hex[len] = '\n';
 583        write_or_die(fd, bisect_rev_hex, len + 1);
 584        bisect_rev_hex[len] = '\0';
 585
 586        if (close(fd) < 0)
 587                die("closing file %s: %s", filename, strerror(errno));
 588}
 589
 590static int bisect_checkout(char *bisect_rev_hex)
 591{
 592        int res;
 593
 594        mark_expected_rev(bisect_rev_hex);
 595
 596        argv_checkout[2] = bisect_rev_hex;
 597        res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
 598        if (res)
 599                exit(res);
 600
 601        argv_show_branch[1] = bisect_rev_hex;
 602        return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
 603}
 604
 605/*
 606 * We use the convention that exiting with an exit code 10 means that
 607 * the bisection process finished successfully.
 608 * In this case the calling shell script should exit 0.
 609 */
 610int bisect_next_exit(const char *prefix)
 611{
 612        struct rev_info revs;
 613        struct commit_list *tried;
 614        int reaches = 0, all = 0, nr;
 615        const unsigned char *bisect_rev;
 616        char bisect_rev_hex[41];
 617
 618        bisect_common(&revs, prefix, &reaches, &all);
 619
 620        revs.commits = filter_skipped(revs.commits, &tried, 0);
 621
 622        if (!revs.commits) {
 623                /*
 624                 * We should exit here only if the "bad"
 625                 * commit is also a "skip" commit.
 626                 */
 627                exit_if_skipped_commits(tried, NULL);
 628
 629                printf("%s was both good and bad\n",
 630                       sha1_to_hex(current_bad_sha1));
 631                exit(1);
 632        }
 633
 634        bisect_rev = revs.commits->item->object.sha1;
 635        memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
 636
 637        if (!hashcmp(bisect_rev, current_bad_sha1)) {
 638                exit_if_skipped_commits(tried, current_bad_sha1);
 639                printf("%s is first bad commit\n", bisect_rev_hex);
 640                argv_diff_tree[2] = bisect_rev_hex;
 641                run_command_v_opt(argv_diff_tree, RUN_GIT_CMD);
 642                /* This means the bisection process succeeded. */
 643                exit(10);
 644        }
 645
 646        nr = all - reaches - 1;
 647        printf("Bisecting: %d revisions left to test after this "
 648               "(roughly %d steps)\n", nr, estimate_bisect_steps(all));
 649
 650        return bisect_checkout(bisect_rev_hex);
 651}
 652