bisect: fix various cases where we leak commit list items

There are various cases where we leak commit list items because we
evict items from the list, but don't free them. Plug those.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

bisect.c

@@ -442,9 +442,12 @@ void find_bisection(struct commit_list **commit_list, int *reaches,
 			best->next = NULL;
 		}
 		*reaches = weight(best);
+	} else {
+		free_commit_list(*commit_list);
 	}
-	free(weights);
 	*commit_list = best;
+
+	free(weights);
 	clear_commit_weight(&commit_weight);
 }
 
@@ -557,8 +560,11 @@ struct commit_list *filter_skipped(struct commit_list *list,
 			tried = &list->next;
 		} else {
 			if (!show_all) {
-				if (!skipped_first || !*skipped_first)
+				if (!skipped_first || !*skipped_first) {
+					free_commit_list(next);
+					free_commit_list(filtered);
 					return list;
+				}
 			} else if (skipped_first && !*skipped_first) {
 				/* This means we know it's not skipped */
 				*skipped_first = -1;
@@ -614,7 +620,7 @@ static int sqrti(int val)
 
 static struct commit_list *skip_away(struct commit_list *list, int count)
 {
-	struct commit_list *cur, *previous;
+	struct commit_list *cur, *previous, *result = list;
 	int prn, index, i;
 
 	prn = get_prn(count);
@@ -626,15 +632,23 @@ static struct commit_list *skip_away(struct commit_list *list, int count)
 	for (i = 0; cur; cur = cur->next, i++) {
 		if (i == index) {
 			if (!oideq(&cur->item->object.oid, current_bad_oid))
-				return cur;
-			if (previous)
-				return previous;
-			return list;
+				result = cur;
+			else if (previous)
+				result = previous;
+			else
+				result = list;
+			break;
 		}
 		previous = cur;
 	}
 
-	return list;
+	for (cur = list; cur != result; ) {
+		struct commit_list *next = cur->next;
+		free(cur);
+		cur = next;
+	}
+
+	return result;
 }
 
 static struct commit_list *managed_skipped(struct commit_list *list,

t/t6030-bisect-porcelain.sh

@@ -9,6 +9,7 @@ exec </dev/null
 GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME=main
 export GIT_TEST_DEFAULT_INITIAL_BRANCH_NAME
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 add_line_into_file()