disabled type hints when using builder or static factory method deserialization

Author: rashtao

src/main/java/com/arangodb/velocypack/VPack.java

@@ -929,7 +929,7 @@ private void addValue(
 				serializeArray(name, value, builder, elemType);
             } else if (type instanceof Class && ((Class) type).isEnum()) {
                 builder.add(name, ((Enum) value).name());
-            } else if (type != value.getClass()) {
+            } else if (shouldAddTypeHint(type, value, fieldInfo)) {
                 addValue(name, value.getClass(), value, builder, fieldInfo,
                         Collections.<String, Object>singletonMap(typeKey, value.getClass().getName()));
             } else {
@@ -938,14 +938,33 @@ private void addValue(
         }
     }
 
-	private void serializeArray(final String name, final Object value, final VPackBuilder builder, final Type type)
+    private boolean shouldAddTypeHint(
+            final Type type,
+            final Object value,
+            final FieldInfo fieldInfo
+    ) {
+        final AnnotatedElement referencingElement = fieldInfo != null ? fieldInfo.getReferencingElement() : null;
+        final BuilderInfo builderInfo = builderUtils.getBuilderInfo(type, referencingElement);
+        if (builderInfo != null) {
+            return false;
+        }
+
+        final VPackCreatorMethodInfo factoryMethodInfo = vPackCreatorMethodUtils.getCreatorMethodInfo(type);
+        if (factoryMethodInfo != null) {
+            return false;
+        }
+
+        return type != value.getClass();
+    }
+
+    private void serializeArray(final String name, final Object value, final VPackBuilder builder, final Type type)
             throws ReflectiveOperationException, VPackException {
         builder.add(name, ValueType.ARRAY);
         for (int i = 0; i < Array.getLength(value); i++) {
             final Object element = Array.get(value, i);
             if (element != null) {
-				final Type t = type != null ? type : element.getClass();
-				addValue(null, t, element, builder, null, Collections.<String, Object> emptyMap());
+                final Type t = type != null ? type : element.getClass();
+                addValue(null, t, element, builder, null, Collections.<String, Object>emptyMap());
             } else {
                 builder.add(ValueType.NULL);
             }

src/test/java/com/arangodb/velocypack/immutable/ImmutablesTest.java

@@ -182,4 +182,33 @@ public void allArgsConstructor() {
 		}
 	}
 
+	@Test
+	public void covariantCollection() {
+		VPack vpack = new VPack.Builder().build();
+		for (int i = 0; i < 3; i++) {
+			PersonWithFriends original = PersonWithFriends.builder()
+					.name("name")
+					.age(987)
+					.friends(Collections.singletonList(
+							Person.builderFunction()
+									.withName("name")
+									.withAge(99)
+									.withSecondNames(Arrays.asList("aaa", "bbb", "ccc"))
+									.withAddresses(Arrays.asList(
+											Collections.singletonMap("home", "Avocado Street 14"),
+											Collections.singletonMap("work", "Java Street 14")
+									))
+									.buildIt()
+					))
+					.build();
+
+			System.out.println(original);
+			VPackSlice serialized = vpack.serialize(original);
+			System.out.println(serialized);
+			PersonWithFriends deserialized = vpack.deserialize(serialized, PersonWithFriends.class);
+			System.out.println(deserialized);
+			assertThat(deserialized, is(original));
+		}
+	}
+
 }

src/test/java/com/arangodb/velocypack/immutable/PersonWithFriends.java

@@ -0,0 +1,45 @@
+/*
+ * DISCLAIMER
+ *
+ * Copyright 2016 ArangoDB GmbH, Cologne, Germany
+ *
+ * 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
+ *
+ *     http://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.
+ *
+ * Copyright holder is ArangoDB GmbH, Cologne, Germany
+ */
+
+package com.arangodb.velocypack.immutable;
+
+import com.arangodb.velocypack.annotations.VPackPOJOBuilder;
+import org.immutables.value.Value;
+
+import java.util.List;
+
+/**
+ * @author Michele Rastelli
+ */
+@Value.Immutable
+public abstract class PersonWithFriends {
+
+	@VPackPOJOBuilder
+	public static ImmutablePersonWithFriends.Builder builder() {
+		return ImmutablePersonWithFriends.builder();
+	}
+
+	abstract String getName();
+
+	abstract int getAge();
+
+	abstract List<Person> getFriends();
+
+}