Document context set method produces unexpected results for arrays #170

json-path/src/main/java/com/jayway/jsonpath/spi/json/GsonJsonProvider.java

@@ -130,11 +130,15 @@ public class GsonJsonProvider extends AbstractJsonProvider {
 
     @Override
     public void setArrayIndex(Object array, int index, Object newValue) {
-        JsonArray a = toJsonArray(array);
-        if (index == a.size()) {
-            a.add(createJsonElement(newValue));
+        if (!isArray(array)) {
+            throw new UnsupportedOperationException();
         } else {
-            a.set(index, createJsonElement(newValue));
+            JsonArray arr = toJsonArray(array);
+            if (index == arr.size()){
+                arr.add(createJsonElement(newValue));
+            }else {
+                arr.set(index, createJsonElement(newValue));
+            }
         }
     }
 

json-path/src/main/java/com/jayway/jsonpath/spi/json/JacksonJsonNodeJsonProvider.java

@@ -131,7 +131,12 @@ public class JacksonJsonNodeJsonProvider extends AbstractJsonProvider {
         if (!isArray(array)) {
             throw new UnsupportedOperationException();
         } else {
-            toJsonArray(array).insert( index, createJsonElement(newValue));
+            ArrayNode arrayNode = toJsonArray(array);
+            if (index == arrayNode.size()){
+                arrayNode.add(createJsonElement(newValue));
+            }else {
+                arrayNode.set(index, createJsonElement(newValue));
+            }
         }
     }
 

json-path/src/test/java/com/jayway/jsonpath/WriteTest.java

@@ -317,5 +317,4 @@ public class WriteTest extends BaseTest {
             return currentValue.toString()+"converted";
         }
     }
-
 }

json-path/src/test/java/com/jayway/jsonpath/old/IssuesTest.java

@@ -31,6 +31,7 @@ import static com.jayway.jsonpath.Criteria.PredicateContext;
 import static com.jayway.jsonpath.Criteria.where;
 import static com.jayway.jsonpath.Filter.filter;
 import static com.jayway.jsonpath.JsonPath.read;
+import static com.jayway.jsonpath.JsonPath.using;
 import static junit.framework.Assert.assertNull;
 import static junit.framework.Assert.assertTrue;
 import static org.assertj.core.api.Assertions.assertThat;
@@ -957,4 +958,26 @@ public class IssuesTest extends BaseTest {
         String object = path.read(json);
 
     }
+
+    @Test
+    public void issue_170() {
+
+        String json = "{\n" +
+                "  \"array\": [\n" +
+                "    0,\n" +
+                "    1,\n" +
+                "    2\n" +
+                "  ]\n" +
+                "}";
+
+
+        DocumentContext context = using(JACKSON_JSON_NODE_CONFIGURATION).parse(json);
+        context = context.set("$.array[0]", null);
+        context = context.set("$.array[2]", null);
+
+        List<Integer> list = context.read("$.array", List.class);
+
+        assertThat(list).containsExactly(null, 1, null);
+
+    }
 }