NPE in $sort when lhs of the comparison evaluates to NULL #68

Author: aeberhart

src/main/java/com/dashjoin/jsonata/Functions.java

@@ -1953,7 +1953,9 @@ public static List sort(List arr, Object comparator) {
                 @Override
                 public int compare(Object o1, Object o2) {
                     try {
-                        boolean swap = (boolean) funcApply(comparator, Arrays.asList(o1, o2));
+                        Boolean swap = toBoolean(funcApply(comparator, Arrays.asList(o1, o2)));
+                        if (swap == null)
+                          return 0;
                         if (swap)
                           return 1;
                         else

src/test/java/com/dashjoin/jsonata/ArrayTest.java

@@ -43,7 +43,6 @@ public void testSort() {
     Assertions.assertEquals(Arrays.asList(Map.of("x", 1), Map.of("x", 2)), expr.evaluate(null));
   }
 
-  @Disabled
   @Test
   public void testSortNull() {
     Jsonata expr = jsonata("$sort([{'x': 2}, {'x': 1}], function($l, $r){$l.y > $r.y})");