DATAMONGO-1772 - Fix UpdateMapper type key rendering for abstract list elements contained in concrete typed ones.

Original pull request: spring-projects#497.

Author: christophstrobl

spring-data-mongodb/src/main/java/org/springframework/data/mongodb/core/convert/UpdateMapper.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2013-2016 the original author or authors.
+ * Copyright 2013-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.springframework.data.mongodb.core.convert;
 
+import java.util.Collection;
 import java.util.Map.Entry;
 
 import org.bson.Document;
@@ -226,6 +227,10 @@ private TypeInformation<?> getTypeHintForEntity(@Nullable Object source, MongoPe
 			return info;
 		}
 
+		if (source instanceof Collection) {
+			return NESTED_DOCUMENT;
+		}
+
 		if (!type.equals(source.getClass())) {
 			return info;
 		}

spring-data-mongodb/src/test/java/org/springframework/data/mongodb/core/convert/UpdateMapperUnitTests.java

@@ -932,6 +932,34 @@ public void mappingShouldConvertMapKeysToString() {
 		}
 	}
 
+	@Test // DATAMONGO-1772
+	public void mappingShouldAddTypeKeyInListOfInterfaceTypeContainedInConcreteObjectCorrectly() {
+
+		ConcreteInner inner = new ConcreteInner();
+		inner.interfaceTypeList = Collections.singletonList(new SomeInterfaceImpl());
+		List<ConcreteInner> list = Collections.singletonList(inner);
+
+		Document mappedUpdate = mapper.getMappedObject(new Update().set("concreteInnerList", list).getUpdateObject(),
+				context.getPersistentEntity(Outer.class));
+
+		assertThat(mappedUpdate, isBsonObject().containing("$set.concreteInnerList.[0].interfaceTypeList.[0]._class")
+				.notContaining("$set.concreteInnerList.[0]._class"));
+	}
+
+	@Test // DATAMONGO-1772
+	public void mappingShouldAddTypeKeyInListOfAbstractTypeContainedInConcreteObjectCorrectly() {
+
+		ConcreteInner inner = new ConcreteInner();
+		inner.abstractTypeList = Collections.singletonList(new SomeInterfaceImpl());
+		List<ConcreteInner> list = Collections.singletonList(inner);
+
+		Document mappedUpdate = mapper.getMappedObject(new Update().set("concreteInnerList", list).getUpdateObject(),
+				context.getPersistentEntity(Outer.class));
+
+		assertThat(mappedUpdate, isBsonObject().containing("$set.concreteInnerList.[0].abstractTypeList.[0]._class")
+				.notContaining("$set.concreteInnerList.[0]._class"));
+	}
+
 	static class DomainTypeWrappingConcreteyTypeHavingListOfInterfaceTypeAttributes {
 		ListModelWrapper concreteTypeWithListAttributeOfInterfaceType;
 	}
@@ -1218,4 +1246,26 @@ static class SimpleValueHolder {
 		Integer intValue;
 		int primIntValue;
 	}
+
+	static class Outer {
+		List<ConcreteInner> concreteInnerList;
+	}
+
+	static class ConcreteInner {
+		List<SomeInterfaceType> interfaceTypeList;
+		List<SomeAbstractType> abstractTypeList;
+	}
+
+	interface SomeInterfaceType {
+
+	}
+
+	static abstract class SomeAbstractType {
+
+	}
+
+	static class SomeInterfaceImpl extends SomeAbstractType implements SomeInterfaceType {
+
+	}
+
 }