Throw exception if requested index is out of bounds

src/xitdb/array_list.clj

@@ -40,8 +40,11 @@
 
   clojure.lang.Indexed
   (nth [_ i]
-    (let [cursor (.getCursor ral (long i))]
-      (common/-read-from-cursor cursor)))
+    (let [count (.count ral)
+          idx   (long i)]
+      (if (and (>= idx 0) (< idx count))
+        (common/-read-from-cursor (.getCursor ral idx))
+        (throw (IndexOutOfBoundsException. (str "Index: " i ", Size: " count))))))
 
   (nth [_ i not-found]
     (let [cursor (.getCursor ral (long i))]

src/xitdb/util/operations.clj

@@ -185,7 +185,7 @@
         cursor    (.getCursor rhs hash-code)]
     (some? cursor)))
 
-(defn ^WriteHashMap set-empty!
+(defn ^WriteHashSet set-empty!
   "Replaces the whs value with an empty set."
   [^WriteHashSet whs]
   (let [empty-set (conversion/v->slot! (.cursor whs) #{})]

test/xitdb/cursor_test.clj

@@ -24,4 +24,7 @@
         (swap! cursor1 assoc-in [3 :hidden] :changed-by-swap!)
         (is (= [1 2 3 {:hidden :changed-by-swap!} 5]) (xdb/materialize @cursor1))
         (is (= :changed-by-swap! @cursor3))
-        (is (= 3 @cursor2))))))
+        (is (= 3 @cursor2)))
+
+      (testing "Correctly handles invalid cursor path"
+        (is (thrown? IndexOutOfBoundsException @(xdb/xdb-cursor db [:foo :bar 999])))))))