" --abbrev=nr | --no-abbrev\n"
" --abbrev-commit\n"
" special purpose:\n"
-" --bisect"
+" --bisect\n"
+" --bisect-vars"
;
static struct rev_info revs;
}
}
-static struct commit_list *find_bisection(struct commit_list *list)
+#define DEBUG_BISECT 0
+
+static inline int weight(struct commit_list *elem)
{
- int nr, closest;
- struct commit_list *p, *best;
+ return *((int*)(elem->item->util));
+}
- nr = 0;
- p = list;
- while (p) {
- if (!revs.prune_fn || (p->item->object.flags & TREECHANGE))
- nr++;
- p = p->next;
+static inline void weight_set(struct commit_list *elem, int weight)
+{
+ *((int*)(elem->item->util)) = weight;
+}
+
+static int count_interesting_parents(struct commit *commit)
+{
+ struct commit_list *p;
+ int count;
+
+ for (count = 0, p = commit->parents; p; p = p->next) {
+ if (p->item->object.flags & UNINTERESTING)
+ continue;
+ count++;
}
- closest = -1;
- best = list;
+ return count;
+}
+
+static inline int halfway(struct commit_list *p, int distance, int nr)
+{
+ /*
+ * Don't short-cut something we are not going to return!
+ */
+ if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
+ return 0;
+ if (DEBUG_BISECT)
+ return 0;
+ /*
+ * 2 and 3 are halfway of 5.
+ * 3 is halfway of 6 but 2 and 4 are not.
+ */
+ distance *= 2;
+ switch (distance - nr) {
+ case -1: case 0: case 1:
+ return 1;
+ default:
+ return 0;
+ }
+}
+
+#if !DEBUG_BISECT
+#define show_list(a,b,c,d) do { ; } while (0)
+#else
+static void show_list(const char *debug, int counted, int nr,
+ struct commit_list *list)
+{
+ struct commit_list *p;
+
+ fprintf(stderr, "%s (%d/%d)\n", debug, counted, nr);
for (p = list; p; p = p->next) {
- int distance;
+ struct commit_list *pp;
+ struct commit *commit = p->item;
+ unsigned flags = commit->object.flags;
+ enum object_type type;
+ unsigned long size;
+ char *buf = read_sha1_file(commit->object.sha1, &type, &size);
+ char *ep, *sp;
+
+ fprintf(stderr, "%c%c%c ",
+ (flags & TREECHANGE) ? 'T' : ' ',
+ (flags & UNINTERESTING) ? 'U' : ' ',
+ (flags & COUNTED) ? 'C' : ' ');
+ if (commit->util)
+ fprintf(stderr, "%3d", weight(p));
+ else
+ fprintf(stderr, "---");
+ fprintf(stderr, " %.*s", 8, sha1_to_hex(commit->object.sha1));
+ for (pp = commit->parents; pp; pp = pp->next)
+ fprintf(stderr, " %.*s", 8,
+ sha1_to_hex(pp->item->object.sha1));
+
+ sp = strstr(buf, "\n\n");
+ if (sp) {
+ sp += 2;
+ for (ep = sp; *ep && *ep != '\n'; ep++)
+ ;
+ fprintf(stderr, " %.*s", (int)(ep - sp), sp);
+ }
+ fprintf(stderr, "\n");
+ }
+}
+#endif /* DEBUG_BISECT */
+
+/*
+ * zero or positive weight is the number of interesting commits it can
+ * reach, including itself. Especially, weight = 0 means it does not
+ * reach any tree-changing commits (e.g. just above uninteresting one
+ * but traversal is with pathspec).
+ *
+ * weight = -1 means it has one parent and its distance is yet to
+ * be computed.
+ *
+ * weight = -2 means it has more than one parent and its distance is
+ * unknown. After running count_distance() first, they will get zero
+ * or positive distance.
+ */
+
+static struct commit_list *find_bisection(struct commit_list *list,
+ int *reaches, int *all)
+{
+ int n, nr, on_list, counted, distance;
+ struct commit_list *p, *best, *next, *last;
+ int *weights;
+
+ show_list("bisection 2 entry", 0, 0, list);
- if (revs.prune_fn && !(p->item->object.flags & TREECHANGE))
+ /*
+ * Count the number of total and tree-changing items on the
+ * list, while reversing the list.
+ */
+ for (nr = on_list = 0, last = NULL, p = list;
+ p;
+ p = next) {
+ unsigned flags = p->item->object.flags;
+
+ next = p->next;
+ if (flags & UNINTERESTING)
continue;
+ p->next = last;
+ last = p;
+ if (!revs.prune_fn || (flags & TREECHANGE))
+ nr++;
+ on_list++;
+ }
+ list = last;
+ show_list("bisection 2 sorted", 0, nr, list);
+
+ *all = nr;
+ weights = xcalloc(on_list, sizeof(int*));
+ counted = 0;
+
+ for (n = 0, p = list; p; p = p->next) {
+ struct commit *commit = p->item;
+ unsigned flags = commit->object.flags;
+
+ p->item->util = &weights[n++];
+ switch (count_interesting_parents(commit)) {
+ case 0:
+ if (!revs.prune_fn || (flags & TREECHANGE)) {
+ weight_set(p, 1);
+ counted++;
+ show_list("bisection 2 count one",
+ counted, nr, list);
+ }
+ /*
+ * otherwise, it is known not to reach any
+ * tree-changing commit and gets weight 0.
+ */
+ break;
+ case 1:
+ weight_set(p, -1);
+ break;
+ default:
+ weight_set(p, -2);
+ break;
+ }
+ }
+ show_list("bisection 2 initialize", counted, nr, list);
+
+ /*
+ * If you have only one parent in the resulting set
+ * then you can reach one commit more than that parent
+ * can reach. So we do not have to run the expensive
+ * count_distance() for single strand of pearls.
+ *
+ * However, if you have more than one parents, you cannot
+ * just add their distance and one for yourself, since
+ * they usually reach the same ancestor and you would
+ * end up counting them twice that way.
+ *
+ * So we will first count distance of merges the usual
+ * way, and then fill the blanks using cheaper algorithm.
+ */
+ for (p = list; p; p = p->next) {
+ if (p->item->object.flags & UNINTERESTING)
+ continue;
+ n = weight(p);
+ if (n != -2)
+ continue;
distance = count_distance(p);
clear_distance(list);
+ weight_set(p, distance);
+
+ /* Does it happen to be at exactly half-way? */
+ if (halfway(p, distance, nr)) {
+ p->next = NULL;
+ *reaches = distance;
+ free(weights);
+ return p;
+ }
+ counted++;
+ }
+
+ show_list("bisection 2 count_distance", counted, nr, list);
+
+ while (counted < nr) {
+ for (p = list; p; p = p->next) {
+ struct commit_list *q;
+ unsigned flags = p->item->object.flags;
+
+ if (0 <= weight(p))
+ continue;
+ for (q = p->item->parents; q; q = q->next) {
+ if (q->item->object.flags & UNINTERESTING)
+ continue;
+ if (0 <= weight(q))
+ break;
+ }
+ if (!q)
+ continue;
+
+ /*
+ * weight for p is unknown but q is known.
+ * add one for p itself if p is to be counted,
+ * otherwise inherit it from q directly.
+ */
+ if (!revs.prune_fn || (flags & TREECHANGE)) {
+ weight_set(p, weight(q)+1);
+ counted++;
+ show_list("bisection 2 count one",
+ counted, nr, list);
+ }
+ else
+ weight_set(p, weight(q));
+
+ /* Does it happen to be at exactly half-way? */
+ distance = weight(p);
+ if (halfway(p, distance, nr)) {
+ p->next = NULL;
+ *reaches = distance;
+ free(weights);
+ return p;
+ }
+ }
+ }
+
+ show_list("bisection 2 counted all", counted, nr, list);
+
+ /* Then find the best one */
+ counted = -1;
+ best = list;
+ for (p = list; p; p = p->next) {
+ unsigned flags = p->item->object.flags;
+
+ if (revs.prune_fn && !(flags & TREECHANGE))
+ continue;
+ distance = weight(p);
if (nr - distance < distance)
distance = nr - distance;
- if (distance > closest) {
+ if (distance > counted) {
best = p;
- closest = distance;
+ counted = distance;
+ *reaches = weight(p);
}
}
if (best)
best->next = NULL;
+ free(weights);
return best;
}
struct commit_list *list;
int i;
int read_from_stdin = 0;
+ int bisect_show_vars = 0;
git_config(git_default_config);
init_revisions(&revs, prefix);
bisect_list = 1;
continue;
}
+ if (!strcmp(arg, "--bisect-vars")) {
+ bisect_list = 1;
+ bisect_show_vars = 1;
+ continue;
+ }
if (!strcmp(arg, "--stdin")) {
if (read_from_stdin++)
die("--stdin given twice?");
if (revs.tree_objects)
mark_edges_uninteresting(revs.commits, &revs, show_edge);
- if (bisect_list)
- revs.commits = find_bisection(revs.commits);
+ if (bisect_list) {
+ int reaches = reaches, all = all;
+
+ revs.commits = find_bisection(revs.commits, &reaches, &all);
+ if (bisect_show_vars) {
+ int cnt;
+ if (!revs.commits)
+ return 1;
+ /*
+ * revs.commits can reach "reaches" commits among
+ * "all" commits. If it is good, then there are
+ * (all-reaches) commits left to be bisected.
+ * On the other hand, if it is bad, then the set
+ * to bisect is "reaches".
+ * A bisect set of size N has (N-1) commits further
+ * to test, as we already know one bad one.
+ */
+ cnt = all-reaches;
+ if (cnt < reaches)
+ cnt = reaches;
+ printf("bisect_rev=%s\n"
+ "bisect_nr=%d\n"
+ "bisect_good=%d\n"
+ "bisect_bad=%d\n"
+ "bisect_all=%d\n",
+ sha1_to_hex(revs.commits->item->object.sha1),
+ cnt - 1,
+ all - reaches - 1,
+ reaches - 1,
+ all);
+ return 0;
+ }
+ }
traverse_commit_list(&revs, show_commit, show_object);