GH-2588 - Replace node creation's MERGE with UNION.

Ensure that no duplicates can get created.

Closes #2588

Author: meistermeier

src/main/java/org/springframework/data/neo4j/core/Neo4jTemplate.java

@@ -968,17 +968,24 @@ private void assignIdToRelationshipProperties(NestedRelationshipContext relation
 
 	private Entity saveRelatedNode(Object entity, NodeDescription<?> targetNodeDescription, PropertyFilter includeProperty, PropertyFilter.RelaxedPropertyPath currentPropertyPath) {
 
-		DynamicLabels dynamicLabels = determineDynamicLabels(entity, (Neo4jPersistentEntity<?>) targetNodeDescription);
+		Neo4jPersistentEntity<?> targetPersistentEntity = (Neo4jPersistentEntity<?>) targetNodeDescription;
+		DynamicLabels dynamicLabels = determineDynamicLabels(entity, targetPersistentEntity);
 		@SuppressWarnings("rawtypes")
-		Class entityType = ((Neo4jPersistentEntity<?>) targetNodeDescription).getType();
+		Class entityType = targetPersistentEntity.getType();
 		@SuppressWarnings("unchecked")
 		Function<Object, Map<String, Object>> binderFunction = neo4jMappingContext.getRequiredBinderFunctionFor(entityType);
 		binderFunction = binderFunction.andThen(tree -> {
 			@SuppressWarnings("unchecked")
 			Map<String, Object> properties = (Map<String, Object>) tree.get(Constants.NAME_OF_PROPERTIES_PARAM);
-
+			String idPropertyName = targetPersistentEntity.getIdProperty().getPropertyName();
+			boolean assignedId = targetPersistentEntity.getIdDescription().isAssignedId();
 			if (!includeProperty.isNotFiltering()) {
-				properties.entrySet().removeIf(e -> !includeProperty.contains(currentPropertyPath.append(e.getKey())));
+				properties.entrySet()
+						.removeIf(e -> {
+							// we cannot skip the id property if it is an assigned id
+							boolean isIdProperty = e.getKey().equals(idPropertyName);
+							return !(assignedId && isIdProperty) && !includeProperty.contains(currentPropertyPath.append(e.getKey()));
+						});
 			}
 			return tree;
 		});
@@ -988,7 +995,7 @@ private Entity saveRelatedNode(Object entity, NodeDescription<?> targetNodeDescr
 				.fetchAs(Entity.class)
 				.one();
 
-		if (((Neo4jPersistentEntity<?>) targetNodeDescription).hasVersionProperty() && !optionalSavedNode.isPresent()) {
+		if (targetPersistentEntity.hasVersionProperty() && !optionalSavedNode.isPresent()) {
 			throw new OptimisticLockingFailureException(OPTIMISTIC_LOCKING_ERROR_MESSAGE);
 		}
 

src/main/java/org/springframework/data/neo4j/core/ReactiveNeo4jTemplate.java

@@ -1067,12 +1067,18 @@ private Mono<Entity> saveRelatedNode(Object relatedNode, Neo4jPersistentEntity<?
 					DynamicLabels dynamicLabels = t.getT2();
 					@SuppressWarnings("unchecked")
 					Function<Object, Map<String, Object>> binderFunction = neo4jMappingContext.getRequiredBinderFunctionFor(entityType);
+					String idPropertyName = targetNodeDescription.getIdProperty().getPropertyName();
+					boolean assignedId = targetNodeDescription.getIdDescription().isAssignedId();
 					binderFunction = binderFunction.andThen(tree -> {
 						@SuppressWarnings("unchecked")
 						Map<String, Object> properties = (Map<String, Object>) tree.get(Constants.NAME_OF_PROPERTIES_PARAM);
 
 						if (!includeProperty.isNotFiltering()) {
-							properties.entrySet().removeIf(e -> !includeProperty.contains(currentPropertyPath.append(e.getKey())));
+							properties.entrySet().removeIf(e -> {
+								// we cannot skip the id property if it is an assigned id
+								boolean isIdProperty = e.getKey().equals(idPropertyName);
+								return !(assignedId && isIdProperty) && !includeProperty.contains(currentPropertyPath.append(e.getKey()));
+							});
 						}
 						return tree;
 					});

src/main/java/org/springframework/data/neo4j/core/TemplateSupport.java

@@ -279,9 +279,15 @@ static <T> FilteredBinderFunction<T> createAndApplyPropertyFilter(
 			@SuppressWarnings("unchecked")
 			Map<String, Object> properties = (Map<String, Object>) tree.get(Constants.NAME_OF_PROPERTIES_PARAM);
 
+			String idPropertyName = entityMetaData.getIdProperty().getPropertyName();
+			boolean assignedId = entityMetaData.getIdDescription().isAssignedId();
 			if (!includeProperty.isNotFiltering()) {
 				properties.entrySet()
-						.removeIf(e -> !includeProperty.contains(e.getKey(), entityMetaData.getUnderlyingClass()));
+						.removeIf(e -> {
+							// we cannot skip the id property if it is an assigned id
+							boolean isIdProperty = e.getKey().equals(idPropertyName);
+							return !(assignedId && isIdProperty) && !includeProperty.contains(e.getKey(), entityMetaData.getUnderlyingClass());
+						});
 			}
 			return tree;
 		}));

src/main/java/org/springframework/data/neo4j/core/mapping/CypherGenerator.java

@@ -301,8 +301,28 @@ public Statement prepareSaveOf(NodeDescription<?> nodeDescription,
 				return Cypher.union(createIfNew, updateIfExists);
 
 			} else {
-				return updateDecorator.apply(Cypher.merge(rootNode.withProperties(nameOfIdProperty, idParameter)).mutate(rootNode,
-						parameter(Constants.NAME_OF_PROPERTIES_PARAM))).returning(rootNode).build();
+//				if (1==1)
+//				return updateDecorator.apply(Cypher.merge(rootNode.withProperties(nameOfIdProperty, idParameter)).mutate(rootNode,
+//						parameter(Constants.NAME_OF_PROPERTIES_PARAM))).returning(rootNode).build();
+				String nameOfPossibleExistingNode = "hlp";
+				Node possibleExistingNode = node(primaryLabel, additionalLabels).named(nameOfPossibleExistingNode);
+
+				Statement createIfNew = updateDecorator.apply(optionalMatch(possibleExistingNode)
+								.where(possibleExistingNode.property(nameOfIdProperty).isEqualTo(idParameter))
+								.with(possibleExistingNode)
+								.where(possibleExistingNode.isNull())
+								.create(rootNode)
+								.with(rootNode)
+								.mutate(rootNode, parameter(Constants.NAME_OF_PROPERTIES_PARAM))).returning(rootNode)
+						.build();
+
+				Statement updateIfExists = updateDecorator.apply(match(rootNode)
+								.where(rootNode.property(nameOfIdProperty).isEqualTo(idParameter))
+								.with(rootNode)
+								.mutate(rootNode, parameter(Constants.NAME_OF_PROPERTIES_PARAM)))
+						.returning(rootNode)
+						.build();
+				return Cypher.union(createIfNew, updateIfExists);
 			}
 		} else {
 			String nameOfPossibleExistingNode = "hlp";

src/test/java/org/springframework/data/neo4j/integration/imperative/Neo4jTemplateIT.java

@@ -117,7 +117,7 @@ void setupData() {
 
 			transaction.run("CREATE (p:Person{firstName: 'A', lastName: 'LA'})");
 			transaction.run("CREATE (p:Person{firstName: 'Michael', lastName: 'Siemons'})" +
-							" -[:LIVES_AT]-> (a:Address {city: 'Aachen'})" +
+							" -[:LIVES_AT]-> (a:Address {city: 'Aachen', id: 1})" +
 							" -[:BASED_IN]->(c:YetAnotherCountryEntity{name: 'Gemany', countryCode: 'DE'})" +
 							" RETURN id(p)");
 			transaction.run(

src/test/java/org/springframework/data/neo4j/integration/reactive/ReactiveNeo4jTemplateIT.java

@@ -117,7 +117,7 @@ void setupData(@Autowired BookmarkCapture bookmarkCapture) {
 			transaction.run("CREATE (p:Person{firstName: 'A', lastName: 'LA'})");
 			simonsId = transaction
 					.run("CREATE (p:Person{firstName: 'Michael', lastName: 'Siemons'})" +
-							"-[:LIVES_AT]->(a:Address {city: 'Aachen'})" +
+							"-[:LIVES_AT]->(a:Address {city: 'Aachen', id: 1})" +
 							"-[:BASED_IN]->(c:YetAnotherCountryEntity{name: 'Gemany', countryCode: 'DE'})" +
 							"RETURN id(p)")
 					.single().get(0).asLong();

src/test/java/org/springframework/data/neo4j/integration/shared/common/Person.java

@@ -39,7 +39,7 @@ public class Person {
 	 */
 	@Node
 	public static class Address {
-		@Id @GeneratedValue private Long id;
+		@Id private Long id;
 		private String zipCode;
 		private String city;
 		private String street;