#include "list-objects.h"
#include "quote.h"
#include "sha1-lookup.h"
+#include "run-command.h"
+#include "log-tree.h"
#include "bisect.h"
-static unsigned char (*skipped_sha1)[20];
-static int skipped_sha1_nr;
-static int skipped_sha1_alloc;
+struct sha1_array {
+ unsigned char (*sha1)[20];
+ int sha1_nr;
+ int sha1_alloc;
+ int sorted;
+};
+
+static struct sha1_array good_revs;
+static struct sha1_array skipped_revs;
+
+static const unsigned char *current_bad_sha1;
+
+struct argv_array {
+ const char **argv;
+ int argv_nr;
+ int argv_alloc;
+};
-static const char **rev_argv;
-static int rev_argv_nr;
-static int rev_argv_alloc;
+static const char *argv_checkout[] = {"checkout", "-q", NULL, "--", NULL};
+static const char *argv_show_branch[] = {"show-branch", NULL, NULL};
/* bits #0-15 in revision.h */
return best;
}
+static void argv_array_push(struct argv_array *array, const char *string)
+{
+ ALLOC_GROW(array->argv, array->argv_nr + 1, array->argv_alloc);
+ array->argv[array->argv_nr++] = string;
+}
+
+static void argv_array_push_sha1(struct argv_array *array,
+ const unsigned char *sha1,
+ const char *format)
+{
+ struct strbuf buf = STRBUF_INIT;
+ strbuf_addf(&buf, format, sha1_to_hex(sha1));
+ argv_array_push(array, strbuf_detach(&buf, NULL));
+}
+
+static void sha1_array_push(struct sha1_array *array,
+ const unsigned char *sha1)
+{
+ ALLOC_GROW(array->sha1, array->sha1_nr + 1, array->sha1_alloc);
+ hashcpy(array->sha1[array->sha1_nr++], sha1);
+}
+
static int register_ref(const char *refname, const unsigned char *sha1,
int flags, void *cb_data)
{
if (!strcmp(refname, "bad")) {
- ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
- rev_argv[rev_argv_nr++] = xstrdup(sha1_to_hex(sha1));
+ current_bad_sha1 = sha1;
} else if (!prefixcmp(refname, "good-")) {
- const char *hex = sha1_to_hex(sha1);
- char *good = xmalloc(strlen(hex) + 2);
- *good = '^';
- memcpy(good + 1, hex, strlen(hex) + 1);
- ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
- rev_argv[rev_argv_nr++] = good;
+ sha1_array_push(&good_revs, sha1);
} else if (!prefixcmp(refname, "skip-")) {
- ALLOC_GROW(skipped_sha1, skipped_sha1_nr + 1,
- skipped_sha1_alloc);
- hashcpy(skipped_sha1[skipped_sha1_nr++], sha1);
+ sha1_array_push(&skipped_revs, sha1);
}
return 0;
return for_each_ref_in("refs/bisect/", register_ref, NULL);
}
-void read_bisect_paths(void)
+static void read_bisect_paths(struct argv_array *array)
{
struct strbuf str = STRBUF_INIT;
const char *filename = git_path("BISECT_NAMES");
FILE *fp = fopen(filename, "r");
if (!fp)
- die("Could not open file '%s': %s", filename, strerror(errno));
+ die_errno("Could not open file '%s'", filename);
while (strbuf_getline(&str, fp, '\n') != EOF) {
char *quoted;
strbuf_trim(&str);
quoted = strbuf_detach(&str, NULL);
- res = sq_dequote_to_argv(quoted, &rev_argv,
- &rev_argv_nr, &rev_argv_alloc);
+ res = sq_dequote_to_argv(quoted, &array->argv,
+ &array->argv_nr, &array->argv_alloc);
if (res)
die("Badly quoted content in file '%s': %s",
filename, quoted);
fclose(fp);
}
-static int skipcmp(const void *a, const void *b)
+static int array_cmp(const void *a, const void *b)
{
return hashcmp(a, b);
}
-static void prepare_skipped(void)
+static void sort_sha1_array(struct sha1_array *array)
+{
+ qsort(array->sha1, array->sha1_nr, sizeof(*array->sha1), array_cmp);
+
+ array->sorted = 1;
+}
+
+static const unsigned char *sha1_access(size_t index, void *table)
{
- qsort(skipped_sha1, skipped_sha1_nr, sizeof(*skipped_sha1), skipcmp);
+ unsigned char (*array)[20] = table;
+ return array[index];
}
-static const unsigned char *skipped_sha1_access(size_t index, void *table)
+static int lookup_sha1_array(struct sha1_array *array,
+ const unsigned char *sha1)
{
- unsigned char (*skipped)[20] = table;
- return skipped[index];
+ if (!array->sorted)
+ sort_sha1_array(array);
+
+ return sha1_pos(sha1, array->sha1, array->sha1_nr, sha1_access);
}
-static int lookup_skipped(unsigned char *sha1)
+static char *join_sha1_array_hex(struct sha1_array *array, char delim)
{
- return sha1_pos(sha1, skipped_sha1, skipped_sha1_nr,
- skipped_sha1_access);
+ struct strbuf joined_hexs = STRBUF_INIT;
+ int i;
+
+ for (i = 0; i < array->sha1_nr; i++) {
+ strbuf_addstr(&joined_hexs, sha1_to_hex(array->sha1[i]));
+ if (i + 1 < array->sha1_nr)
+ strbuf_addch(&joined_hexs, delim);
+ }
+
+ return strbuf_detach(&joined_hexs, NULL);
}
+/*
+ * In this function, passing a not NULL skipped_first is very special.
+ * It means that we want to know if the first commit in the list is
+ * skipped because we will want to test a commit away from it if it is
+ * indeed skipped.
+ * So if the first commit is skipped, we cannot take the shortcut to
+ * just "return list" when we find the first non skipped commit, we
+ * have to return a fully filtered list.
+ *
+ * We use (*skipped_first == -1) to mean "it has been found that the
+ * first commit is not skipped". In this case *skipped_first is set back
+ * to 0 just before the function returns.
+ */
struct commit_list *filter_skipped(struct commit_list *list,
struct commit_list **tried,
- int show_all)
+ int show_all,
+ int *count,
+ int *skipped_first)
{
struct commit_list *filtered = NULL, **f = &filtered;
*tried = NULL;
- if (!skipped_sha1_nr)
- return list;
+ if (skipped_first)
+ *skipped_first = 0;
+ if (count)
+ *count = 0;
- prepare_skipped();
+ if (!skipped_revs.sha1_nr)
+ return list;
while (list) {
struct commit_list *next = list->next;
list->next = NULL;
- if (0 <= lookup_skipped(list->item->object.sha1)) {
+ if (0 <= lookup_sha1_array(&skipped_revs,
+ list->item->object.sha1)) {
+ if (skipped_first && !*skipped_first)
+ *skipped_first = 1;
/* Move current to tried list */
*tried = list;
tried = &list->next;
} else {
- if (!show_all)
- return list;
+ if (!show_all) {
+ if (!skipped_first || !*skipped_first)
+ return list;
+ } else if (skipped_first && !*skipped_first) {
+ /* This means we know it's not skipped */
+ *skipped_first = -1;
+ }
/* Move current to filtered list */
*f = list;
f = &list->next;
+ if (count)
+ (*count)++;
}
list = next;
}
+ if (skipped_first && *skipped_first == -1)
+ *skipped_first = 0;
+
return filtered;
}
-static void bisect_rev_setup(struct rev_info *revs, const char *prefix)
+#define PRN_MODULO 32768
+
+/*
+ * This is a pseudo random number generator based on "man 3 rand".
+ * It is not used properly because the seed is the argument and it
+ * is increased by one between each call, but that should not matter
+ * for this application.
+ */
+int get_prn(int count) {
+ count = count * 1103515245 + 12345;
+ return ((unsigned)(count/65536) % PRN_MODULO);
+}
+
+/*
+ * Custom integer square root from
+ * http://en.wikipedia.org/wiki/Integer_square_root
+ */
+static int sqrti(int val)
+{
+ float d, x = val;
+
+ if (val == 0)
+ return 0;
+
+ do {
+ float y = (x + (float)val / x) / 2;
+ d = (y > x) ? y - x : x - y;
+ x = y;
+ } while (d >= 0.5);
+
+ return (int)x;
+}
+
+static struct commit_list *skip_away(struct commit_list *list, int count)
+{
+ struct commit_list *cur, *previous;
+ int prn, index, i;
+
+ prn = get_prn(count);
+ index = (count * prn / PRN_MODULO) * sqrti(prn) / sqrti(PRN_MODULO);
+
+ cur = list;
+ previous = NULL;
+
+ for (i = 0; cur; cur = cur->next, i++) {
+ if (i == index) {
+ if (hashcmp(cur->item->object.sha1, current_bad_sha1))
+ return cur;
+ if (previous)
+ return previous;
+ return list;
+ }
+ previous = cur;
+ }
+
+ return list;
+}
+
+static struct commit_list *managed_skipped(struct commit_list *list,
+ struct commit_list **tried)
+{
+ int count, skipped_first;
+
+ *tried = NULL;
+
+ if (!skipped_revs.sha1_nr)
+ return list;
+
+ list = filter_skipped(list, tried, 0, &count, &skipped_first);
+
+ if (!skipped_first)
+ return list;
+
+ return skip_away(list, count);
+}
+
+static void bisect_rev_setup(struct rev_info *revs, const char *prefix,
+ const char *bad_format, const char *good_format,
+ int read_paths)
{
+ struct argv_array rev_argv = { NULL, 0, 0 };
+ int i;
+
init_revisions(revs, prefix);
revs->abbrev = 0;
revs->commit_format = CMIT_FMT_UNSPECIFIED;
- /* argv[0] will be ignored by setup_revisions */
- ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
- rev_argv[rev_argv_nr++] = xstrdup("bisect_rev_setup");
+ /* rev_argv.argv[0] will be ignored by setup_revisions */
+ argv_array_push(&rev_argv, xstrdup("bisect_rev_setup"));
+ argv_array_push_sha1(&rev_argv, current_bad_sha1, bad_format);
+ for (i = 0; i < good_revs.sha1_nr; i++)
+ argv_array_push_sha1(&rev_argv, good_revs.sha1[i],
+ good_format);
+ argv_array_push(&rev_argv, xstrdup("--"));
+ if (read_paths)
+ read_bisect_paths(&rev_argv);
+ argv_array_push(&rev_argv, NULL);
+
+ setup_revisions(rev_argv.argv_nr, rev_argv.argv, revs, NULL);
+}
- if (read_bisect_refs())
- die("reading bisect refs failed");
+static void bisect_common(struct rev_info *revs)
+{
+ if (prepare_revision_walk(revs))
+ die("revision walk setup failed");
+ if (revs->tree_objects)
+ mark_edges_uninteresting(revs->commits, revs, NULL);
+}
+
+static void exit_if_skipped_commits(struct commit_list *tried,
+ const unsigned char *bad)
+{
+ if (!tried)
+ return;
+
+ printf("There are only 'skip'ped commits left to test.\n"
+ "The first bad commit could be any of:\n");
+ print_commit_list(tried, "%s\n", "%s\n");
+ if (bad)
+ printf("%s\n", sha1_to_hex(bad));
+ printf("We cannot bisect more!\n");
+ exit(2);
+}
+
+static int is_expected_rev(const unsigned char *sha1)
+{
+ const char *filename = git_path("BISECT_EXPECTED_REV");
+ struct stat st;
+ struct strbuf str = STRBUF_INIT;
+ FILE *fp;
+ int res = 0;
+
+ if (stat(filename, &st) || !S_ISREG(st.st_mode))
+ return 0;
+
+ fp = fopen(filename, "r");
+ if (!fp)
+ return 0;
+
+ if (strbuf_getline(&str, fp, '\n') != EOF)
+ res = !strcmp(str.buf, sha1_to_hex(sha1));
- ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
- rev_argv[rev_argv_nr++] = xstrdup("--");
+ strbuf_release(&str);
+ fclose(fp);
+
+ return res;
+}
+
+static void mark_expected_rev(char *bisect_rev_hex)
+{
+ int len = strlen(bisect_rev_hex);
+ const char *filename = git_path("BISECT_EXPECTED_REV");
+ int fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+
+ if (fd < 0)
+ die_errno("could not create file '%s'", filename);
+
+ bisect_rev_hex[len] = '\n';
+ write_or_die(fd, bisect_rev_hex, len + 1);
+ bisect_rev_hex[len] = '\0';
+
+ if (close(fd) < 0)
+ die("closing file %s: %s", filename, strerror(errno));
+}
+
+static int bisect_checkout(char *bisect_rev_hex)
+{
+ int res;
+
+ mark_expected_rev(bisect_rev_hex);
+
+ argv_checkout[2] = bisect_rev_hex;
+ res = run_command_v_opt(argv_checkout, RUN_GIT_CMD);
+ if (res)
+ exit(res);
+
+ argv_show_branch[1] = bisect_rev_hex;
+ return run_command_v_opt(argv_show_branch, RUN_GIT_CMD);
+}
+
+static struct commit *get_commit_reference(const unsigned char *sha1)
+{
+ struct commit *r = lookup_commit_reference(sha1);
+ if (!r)
+ die("Not a valid commit name %s", sha1_to_hex(sha1));
+ return r;
+}
+
+static struct commit **get_bad_and_good_commits(int *rev_nr)
+{
+ int len = 1 + good_revs.sha1_nr;
+ struct commit **rev = xmalloc(len * sizeof(*rev));
+ int i, n = 0;
+
+ rev[n++] = get_commit_reference(current_bad_sha1);
+ for (i = 0; i < good_revs.sha1_nr; i++)
+ rev[n++] = get_commit_reference(good_revs.sha1[i]);
+ *rev_nr = n;
+
+ return rev;
+}
+
+static void handle_bad_merge_base(void)
+{
+ if (is_expected_rev(current_bad_sha1)) {
+ char *bad_hex = sha1_to_hex(current_bad_sha1);
+ char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+
+ fprintf(stderr, "The merge base %s is bad.\n"
+ "This means the bug has been fixed "
+ "between %s and [%s].\n",
+ bad_hex, bad_hex, good_hex);
+
+ exit(3);
+ }
+
+ fprintf(stderr, "Some good revs are not ancestor of the bad rev.\n"
+ "git bisect cannot work properly in this case.\n"
+ "Maybe you mistake good and bad revs?\n");
+ exit(1);
+}
+
+static void handle_skipped_merge_base(const unsigned char *mb)
+{
+ char *mb_hex = sha1_to_hex(mb);
+ char *bad_hex = sha1_to_hex(current_bad_sha1);
+ char *good_hex = join_sha1_array_hex(&good_revs, ' ');
+
+ fprintf(stderr, "Warning: the merge base between %s and [%s] "
+ "must be skipped.\n"
+ "So we cannot be sure the first bad commit is "
+ "between %s and %s.\n"
+ "We continue anyway.\n",
+ bad_hex, good_hex, mb_hex, bad_hex);
+ free(good_hex);
+}
+
+/*
+ * "check_merge_bases" checks that merge bases are not "bad".
+ *
+ * - If one is "bad", it means the user assumed something wrong
+ * and we must exit with a non 0 error code.
+ * - If one is "good", that's good, we have nothing to do.
+ * - If one is "skipped", we can't know but we should warn.
+ * - If we don't know, we should check it out and ask the user to test.
+ */
+static void check_merge_bases(void)
+{
+ struct commit_list *result;
+ int rev_nr;
+ struct commit **rev = get_bad_and_good_commits(&rev_nr);
+
+ result = get_merge_bases_many(rev[0], rev_nr - 1, rev + 1, 0);
- read_bisect_paths();
+ for (; result; result = result->next) {
+ const unsigned char *mb = result->item->object.sha1;
+ if (!hashcmp(mb, current_bad_sha1)) {
+ handle_bad_merge_base();
+ } else if (0 <= lookup_sha1_array(&good_revs, mb)) {
+ continue;
+ } else if (0 <= lookup_sha1_array(&skipped_revs, mb)) {
+ handle_skipped_merge_base(mb);
+ } else {
+ printf("Bisecting: a merge base must be tested\n");
+ exit(bisect_checkout(sha1_to_hex(mb)));
+ }
+ }
+
+ free(rev);
+ free_commit_list(result);
+}
+
+static int check_ancestors(const char *prefix)
+{
+ struct rev_info revs;
+ struct object_array pending_copy;
+ int i, res;
+
+ bisect_rev_setup(&revs, prefix, "^%s", "%s", 0);
+
+ /* Save pending objects, so they can be cleaned up later. */
+ memset(&pending_copy, 0, sizeof(pending_copy));
+ for (i = 0; i < revs.pending.nr; i++)
+ add_object_array(revs.pending.objects[i].item,
+ revs.pending.objects[i].name,
+ &pending_copy);
+
+ bisect_common(&revs);
+ res = (revs.commits != NULL);
+
+ /* Clean up objects used, as they will be reused. */
+ for (i = 0; i < pending_copy.nr; i++) {
+ struct object *o = pending_copy.objects[i].item;
+ clear_commit_marks((struct commit *)o, ALL_REV_FLAGS);
+ }
+
+ return res;
+}
+
+/*
+ * "check_good_are_ancestors_of_bad" checks that all "good" revs are
+ * ancestor of the "bad" rev.
+ *
+ * If that's not the case, we need to check the merge bases.
+ * If a merge base must be tested by the user, its source code will be
+ * checked out to be tested by the user and we will exit.
+ */
+static void check_good_are_ancestors_of_bad(const char *prefix)
+{
+ const char *filename = git_path("BISECT_ANCESTORS_OK");
+ struct stat st;
+ int fd;
+
+ if (!current_bad_sha1)
+ die("a bad revision is needed");
+
+ /* Check if file BISECT_ANCESTORS_OK exists. */
+ if (!stat(filename, &st) && S_ISREG(st.st_mode))
+ return;
+
+ /* Bisecting with no good rev is ok. */
+ if (good_revs.sha1_nr == 0)
+ return;
+
+ /* Check if all good revs are ancestor of the bad rev. */
+ if (check_ancestors(prefix))
+ check_merge_bases();
+
+ /* Create file BISECT_ANCESTORS_OK. */
+ fd = open(filename, O_CREAT | O_TRUNC | O_WRONLY, 0600);
+ if (fd < 0)
+ warning("could not create file '%s': %s",
+ filename, strerror(errno));
+ else
+ close(fd);
+}
+
+/*
+ * This does "git diff-tree --pretty COMMIT" without one fork+exec.
+ */
+static void show_diff_tree(const char *prefix, struct commit *commit)
+{
+ struct rev_info opt;
+
+ /* diff-tree init */
+ init_revisions(&opt, prefix);
+ git_config(git_diff_basic_config, NULL); /* no "diff" UI options */
+ opt.abbrev = 0;
+ opt.diff = 1;
- ALLOC_GROW(rev_argv, rev_argv_nr + 1, rev_argv_alloc);
- rev_argv[rev_argv_nr++] = NULL;
+ /* This is what "--pretty" does */
+ opt.verbose_header = 1;
+ opt.use_terminator = 0;
+ opt.commit_format = CMIT_FMT_DEFAULT;
- setup_revisions(rev_argv_nr, rev_argv, revs, NULL);
+ /* diff-tree init */
+ if (!opt.diffopt.output_format)
+ opt.diffopt.output_format = DIFF_FORMAT_RAW;
- revs->limited = 1;
+ log_tree_commit(&opt, commit);
}
-int bisect_next_vars(const char *prefix)
+/*
+ * We use the convention that exiting with an exit code 10 means that
+ * the bisection process finished successfully.
+ * In this case the calling shell script should exit 0.
+ */
+int bisect_next_all(const char *prefix)
{
struct rev_info revs;
- struct rev_list_info info;
- int reaches = 0, all = 0;
+ struct commit_list *tried;
+ int reaches = 0, all = 0, nr;
+ const unsigned char *bisect_rev;
+ char bisect_rev_hex[41];
- memset(&info, 0, sizeof(info));
- info.revs = &revs;
- info.bisect_show_flags = BISECT_SHOW_TRIED | BISECT_SHOW_STRINGED;
+ if (read_bisect_refs())
+ die("reading bisect refs failed");
- bisect_rev_setup(&revs, prefix);
+ check_good_are_ancestors_of_bad(prefix);
- if (prepare_revision_walk(&revs))
- die("revision walk setup failed");
- if (revs.tree_objects)
- mark_edges_uninteresting(revs.commits, &revs, NULL);
+ bisect_rev_setup(&revs, prefix, "%s", "^%s", 1);
+ revs.limited = 1;
+
+ bisect_common(&revs);
revs.commits = find_bisection(revs.commits, &reaches, &all,
- !!skipped_sha1_nr);
+ !!skipped_revs.sha1_nr);
+ revs.commits = managed_skipped(revs.commits, &tried);
+
+ if (!revs.commits) {
+ /*
+ * We should exit here only if the "bad"
+ * commit is also a "skip" commit.
+ */
+ exit_if_skipped_commits(tried, NULL);
+
+ printf("%s was both good and bad\n",
+ sha1_to_hex(current_bad_sha1));
+ exit(1);
+ }
- return show_bisect_vars(&info, reaches, all);
+ bisect_rev = revs.commits->item->object.sha1;
+ memcpy(bisect_rev_hex, sha1_to_hex(bisect_rev), 41);
+
+ if (!hashcmp(bisect_rev, current_bad_sha1)) {
+ exit_if_skipped_commits(tried, current_bad_sha1);
+ printf("%s is the first bad commit\n", bisect_rev_hex);
+ show_diff_tree(prefix, revs.commits->item);
+ /* This means the bisection process succeeded. */
+ exit(10);
+ }
+
+ nr = all - reaches - 1;
+ printf("Bisecting: %d revisions left to test after this "
+ "(roughly %d steps)\n", nr, estimate_bisect_steps(all));
+
+ return bisect_checkout(bisect_rev_hex);
}
+