Fix jsonNode#addAll (#2443)

Fix #2442: ArrayNode.addAll() needs to handle `null` entries

Author: heshamMassoud

src/main/java/com/fasterxml/jackson/databind/node/ArrayNode.java

@@ -316,7 +316,9 @@ public ArrayNode addAll(ArrayNode other)
      */
     public ArrayNode addAll(Collection<? extends JsonNode> nodes)
     {
-        _children.addAll(nodes);
+        for (JsonNode node : nodes) {
+            add(node);
+        }
         return this;
     }
 

src/test/java/com/fasterxml/jackson/databind/node/ArrayNodeTest.java

@@ -12,6 +12,7 @@
 import com.fasterxml.jackson.databind.node.JsonNodeFactory;
 import com.fasterxml.jackson.databind.node.TextNode;
 import com.fasterxml.jackson.databind.node.TreeTraversingParser;
+import static java.util.Arrays.asList;
 
 /**
  * Additional tests for {@link ArrayNode} container class.
@@ -186,6 +187,23 @@ public void testNullAdds()
         }
     }
 
+    public void testAddAllWithNullInCollection()
+    {
+        // preparation
+        final ArrayNode array = JsonNodeFactory.instance.arrayNode();
+
+        // test
+        array.addAll(asList(null, JsonNodeFactory.instance.objectNode()));
+
+        // assertions
+        assertEquals(2, array.size());
+
+        for (JsonNode node : array) {
+            assertFalse(node.isNull());
+        }
+        assertEquals(NullNode.getInstance(), array.get(0));
+    }
+
     public void testNullInserts()
     {
         JsonNodeFactory f = objectMapper().getNodeFactory();