Handle null values

src/main/java/io/lettuce/core/json/DefaultJsonParser.java

@@ -3,23 +3,11 @@
  * All rights reserved.
  *
  * Licensed under the MIT License.
- *
- * This file contains contributions from third-party contributors
- * licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
  */
 
 package io.lettuce.core.json;
 
+import com.fasterxml.jackson.core.JsonProcessingException;
 import com.fasterxml.jackson.databind.JsonNode;
 import com.fasterxml.jackson.databind.ObjectMapper;
 import io.lettuce.core.codec.RedisCodec;
@@ -69,15 +57,10 @@ private JsonValue<K, V> parse(String value) {
         ObjectMapper mapper = new ObjectMapper();
         try {
             JsonNode root = mapper.readTree(value);
-
-            if (root.isObject()) {
-                return new DelegateJsonObject<>(root, codec);
-            } else if (root.isArray()) {
-                return new DelegateJsonArray<>(root, codec);
-            }
-            return new DelegateJsonValue<>(root, codec);
-        } catch (IOException e) {
-            throw new RuntimeException(e);
+            return wrap(root);
+        } catch (JsonProcessingException e) {
+            throw new RedisJsonException(
+                    "Failed to process the provided value as JSON: " + String.format("%.50s", value) + "...", e);
         }
     }
 
@@ -89,15 +72,20 @@ public JsonValue<K, V> parse(ByteBuffer byteBuffer) {
             byteBuffer.get(bytes);
             JsonNode root = mapper.readTree(bytes);
 
-            if (root.isObject()) {
-                return new DelegateJsonObject<>(root, codec);
-            } else if (root.isArray()) {
-                return new DelegateJsonArray<>(root, codec);
-            }
-            return new DelegateJsonValue<>(root, codec);
+            return wrap(root);
         } catch (IOException e) {
             throw new RuntimeException(e);
         }
     }
 
+    private JsonValue<K, V> wrap(JsonNode root) {
+        if (root.isObject()) {
+            return new DelegateJsonObject<>(root, codec);
+        } else if (root.isArray()) {
+            return new DelegateJsonArray<>(root, codec);
+        }
+
+        return new DelegateJsonValue<>(root, codec);
+    }
+
 }

src/main/java/io/lettuce/core/json/DelegateJsonArray.java

@@ -145,4 +145,9 @@ public Number asNumber() {
         throw new UnsupportedOperationException("The JSON value is not a number");
     }
 
+    @Override
+    public boolean isNull() {
+        return false;
+    }
+
 }

src/main/java/io/lettuce/core/json/DelegateJsonObject.java

@@ -102,4 +102,9 @@ public Number asNumber() {
         throw new UnsupportedOperationException("The JSON value is not a number");
     }
 
+    @Override
+    public boolean isNull() {
+        return false;
+    }
+
 }

src/main/java/io/lettuce/core/json/DelegateJsonValue.java

@@ -91,6 +91,10 @@ public boolean isNumber() {
         return node.isNumber();
     }
 
+    public boolean isNull() {
+        return node.isNull();
+    }
+
     @Override
     public Number asNumber() {
         if (node.isInt()) {

src/main/java/io/lettuce/core/json/JsonValue.java

@@ -99,4 +99,9 @@ public interface JsonValue<K, V> {
      */
     Number asNumber();
 
+    /**
+     * @return {@code true} if this {@link JsonValue} represents the value of null
+     */
+    boolean isNull();
+
 }

src/main/java/io/lettuce/core/json/RedisJsonException.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2024, Redis Ltd. and Contributors
+ * All rights reserved.
+ *
+ * Licensed under the MIT License.
+ *
+ * This file contains contributions from third-party contributors
+ * licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.lettuce.core.json;
+
+public class RedisJsonException extends RuntimeException {
+
+    public RedisJsonException(String message) {
+        super(message);
+    }
+
+    public RedisJsonException(String message, Throwable cause) {
+        super(message, cause);
+    }
+
+    public RedisJsonException(Throwable cause) {
+        super(cause);
+    }
+
+}

src/main/java/io/lettuce/core/json/UnproccessedJsonValue.java

@@ -112,6 +112,12 @@ public Number asNumber() {
         return jsonValue.asNumber();
     }
 
+    @Override
+    public boolean isNull() {
+        lazilyDeserialize();
+        return jsonValue.isNull();
+    }
+
     private void lazilyDeserialize() {
         if (deserialized) {
             return;

src/test/java/io/lettuce/core/json/RedisJsonIntegrationTests.java

@@ -174,6 +174,7 @@ void jsonGet(String path) {
             assertThat(value.get(0).asJsonArray().asList().get(0).isString()).isTrue();
             assertThat(value.get(0).asJsonArray().asList().get(0).asString()).isEqualTo("Phoebe");
             assertThat(value.get(0).asJsonArray().asList().get(1).isString()).isTrue();
+            assertThat(value.get(0).asJsonArray().asList().get(1).isNull()).isFalse();
             assertThat(value.get(0).asJsonArray().asList().get(1).asString()).isEqualTo("Quaoar");
         } else {
             assertThat(value.get(0).toValue()).isEqualTo("\"Phoebe\"");
@@ -184,6 +185,23 @@ void jsonGet(String path) {
         }
     }
 
+    @Test
+    void jsonGetNull() {
+        JsonPath myPath = JsonPath.of("$..inventory.owner");
+
+        // Verify codec parsing
+        List<JsonValue<String, String>> value = redis.jsonGet(BIKES_INVENTORY, JsonGetArgs.Builder.none(), myPath);
+        assertThat(value).hasSize(1);
+
+        assertThat(value.get(0).toValue()).isEqualTo("[null]");
+
+        // Verify array parsing
+        assertThat(value.get(0).isJsonArray()).isTrue();
+        assertThat(value.get(0).asJsonArray().size()).isEqualTo(1);
+        assertThat(value.get(0).asJsonArray().asList().get(0).toValue()).isEqualTo("null");
+        assertThat(value.get(0).asJsonArray().asList().get(0).isNull()).isTrue();
+    }
+
     @ParameterizedTest(name = "With {0} as path")
     @ValueSource(strings = { MOUNTAIN_BIKES_V1 + "[1]", MOUNTAIN_BIKES_V2 + "[1]" })
     void jsonMerge(String path) {
@@ -355,7 +373,7 @@ void jsonSet(String path) {
         JsonObject<String, String> bikeSpecs = parser.createEmptyJsonObject();
         JsonArray<String, String> bikeColors = parser.createEmptyJsonArray();
 
-        bikeSpecs.put("material", parser.createJsonValue("\"composite\""));
+        bikeSpecs.put("material", parser.createJsonValue("null"));
         bikeSpecs.put("weight", parser.createJsonValue("11"));
 
         bikeColors.add(parser.createJsonValue("\"yellow\""));

src/test/resources/bike-inventory.json

@@ -1,6 +1,7 @@
 {
   "inventory": {
     "complete": false,
+    "owner": null,
     "mountain_bikes": [
       {
         "id": "bike:1",