Handle null values gracefully (#34)

Author: GurtejSohi

config-service-impl/src/main/java/org/hypertrace/config/service/store/ConfigDocument.java

@@ -17,6 +17,7 @@
 import com.google.protobuf.Value;
 import com.google.protobuf.util.JsonFormat;
 import lombok.extern.slf4j.Slf4j;
+import org.hypertrace.config.service.ConfigServiceUtils;
 import org.hypertrace.core.documentstore.Document;
 
 import java.io.IOException;
@@ -124,5 +125,10 @@ public Value deserialize(JsonParser p, DeserializationContext ctxt)
       JsonFormat.parser().merge(jsonString, valueBuilder);
       return valueBuilder.build();
     }
+
+    @Override
+    public Value getNullValue(DeserializationContext ctxt) {
+      return ConfigServiceUtils.emptyValue();
+    }
   }
 }

config-service-impl/src/test/java/org/hypertrace/config/service/store/ConfigDocumentTest.java

@@ -8,6 +8,9 @@
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 import com.google.common.io.Resources;
+import com.google.protobuf.NullValue;
+import com.google.protobuf.Value;
+import com.google.protobuf.util.JsonFormat;
 import java.io.IOException;
 import java.nio.charset.Charset;
 import org.junit.jupiter.api.DisplayName;
@@ -23,6 +26,15 @@ void convertToAndFromJson() throws IOException {
     assertEquals(configDocument, ConfigDocument.fromJson(configDocument.toJson()));
   }
 
+  @Test
+  void convertDocumentContainingNullValue() throws IOException {
+    long timestamp = System.currentTimeMillis();
+    Value nullValue = Value.newBuilder().setNullValue(NullValue.NULL_VALUE).build();
+    ConfigDocument configDocument = new ConfigDocument(RESOURCE_NAME, RESOURCE_NAMESPACE,
+        TENANT_ID, DEFAULT_CONTEXT, 15, "user1", nullValue, timestamp, timestamp);
+    assertEquals(configDocument, ConfigDocument.fromJson(configDocument.toJson()));
+  }
+
   @Test
   @DisplayName("Test backward compatibility using a json string without creation and update timestamps")
   void convertJsonStringWithoutTimestamp() throws IOException {