DATAREST-1383 - PATCH requests now skip application of values for backend read-only properties.

MappedProperties now immediately drops non-writable properties when created for deserialization. Previously those properties would have to be annotated with @JsonProperty(access = Access.READ_ONLY) explicitly to avoid them being considered.

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/json/DomainObjectReader.java

@@ -227,6 +227,7 @@ public class DomainObjectReader {
 			String fieldName = entry.getKey();
 
 			if (!mappedProperties.hasPersistentPropertyForField(fieldName)) {
+				i.remove();
 				continue;
 			}
 

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/json/MappedProperties.java

@@ -26,6 +26,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
+import java.util.function.Predicate;
 
 import org.springframework.data.mapping.PersistentEntity;
 import org.springframework.data.mapping.PersistentProperty;
@@ -61,7 +62,8 @@ class MappedProperties {
 	 * @param entity must not be {@literal null}.
 	 * @param description must not be {@literal null}.
 	 */
-	private MappedProperties(PersistentEntity<?, ? extends PersistentProperty<?>> entity, BeanDescription description) {
+	private MappedProperties(PersistentEntity<?, ? extends PersistentProperty<?>> entity, BeanDescription description,
+			Predicate<PersistentProperty<?>> filter) {
 
 		Assert.notNull(entity, "Entity must not be null!");
 		Assert.notNull(description, "BeanDescription must not be null!");
@@ -79,10 +81,12 @@ class MappedProperties {
 			Optional<? extends PersistentProperty<?>> persistentProperty = //
 					Optional.ofNullable(entity.getPersistentProperty(property.getInternalName()));
 
-			persistentProperty.ifPresent(it -> {
-				propertyToFieldName.put(it, property);
-				fieldNameToProperty.put(property.getName(), it);
-			});
+			persistentProperty//
+					.filter(filter) //
+					.ifPresent(it -> {
+						propertyToFieldName.put(it, property);
+						fieldNameToProperty.put(property.getName(), it);
+					});
 
 			if (!persistentProperty.isPresent()) {
 				unmappedProperties.add(property);
@@ -104,7 +108,7 @@ class MappedProperties {
 		BeanDescription description = INTROSPECTOR.forDeserialization(config, mapper.constructType(entity.getType()),
 				config);
 
-		return new MappedProperties(entity, description);
+		return new MappedProperties(entity, description, it -> it.isWritable());
 	}
 
 	/**
@@ -120,7 +124,7 @@ class MappedProperties {
 		SerializationConfig config = mapper.getSerializationConfig();
 		BeanDescription description = INTROSPECTOR.forSerialization(config, mapper.constructType(entity.getType()), config);
 
-		return new MappedProperties(entity, description);
+		return new MappedProperties(entity, description, it -> true);
 	}
 
 	public static MappedProperties none() {

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/json/DomainObjectReaderUnitTests.java

@@ -569,6 +569,22 @@ public class DomainObjectReaderUnitTests {
 		assertThat(result.strings).containsExactly("value");
 	}
 
+	@Test // DATAREST-1383
+	public void doesNotWipeReadOnlyPropertyForPatch() throws Exception {
+
+		SampleUser user = new SampleUser("name", "password");
+		user.lastLogin = new Date();
+		user.email = "foo@bar.com";
+
+		ObjectMapper mapper = new ObjectMapper();
+		ObjectNode source = (ObjectNode) mapper.readTree("{ \"lastLogin\" : null, \"email\" : \"bar@foo.com\"}");
+
+		SampleUser result = reader.merge(source, user, mapper);
+
+		assertThat(result.lastLogin).isNotNull();
+		assertThat(result.email).isEqualTo("foo@bar.com");
+	}
+
 	@SuppressWarnings("unchecked")
 	private static <T> T as(Object source, Class<T> type) {
 
@@ -586,6 +602,9 @@ public class DomainObjectReaderUnitTests {
 		@JsonProperty(access = READ_ONLY) //
 		private Date lastLogin;
 
+		@ReadOnlyProperty //
+		private String email;
+
 		public SampleUser(String name, String password) {
 
 			this.name = name;

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/json/MappedPropertiesUnitTests.java

@@ -18,6 +18,7 @@ package org.springframework.data.rest.webmvc.json;
 import static org.assertj.core.api.Assertions.*;
 
 import org.junit.Test;
+import org.springframework.data.annotation.ReadOnlyProperty;
 import org.springframework.data.annotation.Transient;
 import org.springframework.data.keyvalue.core.mapping.context.KeyValueMappingContext;
 import org.springframework.data.mapping.PersistentEntity;
@@ -84,6 +85,20 @@ public class MappedPropertiesUnitTests {
 		assertThat(properties.getPersistentProperty("readOnlyProperty")).isNotNull();
 	}
 
+	@Test // DATAREST-1383
+	public void doesNotRegardReadOnlyPropertyForDeserialization() {
+
+		MappedProperties properties = MappedProperties.forDeserialization(entity, mapper);
+
+		assertThat(properties.hasPersistentPropertyForField("anotherReadOnlyProperty")).isFalse();
+		assertThat(properties.getPersistentProperty("readOnlyProperty")).isNull();
+
+		properties = MappedProperties.forSerialization(entity, mapper);
+
+		assertThat(properties.hasPersistentPropertyForField("anotherReadOnlyProperty")).isTrue();
+		assertThat(properties.getPersistentProperty("readOnlyProperty")).isNotNull();
+	}
+
 	static class Sample {
 
 		public @Transient String notExposedBySpringData;
@@ -91,5 +106,6 @@ public class MappedPropertiesUnitTests {
 		public String exposedProperty;
 		public @JsonProperty("email") String emailAddress;
 		public @JsonProperty(access = Access.READ_ONLY) String readOnlyProperty;
+		public @ReadOnlyProperty String anotherReadOnlyProperty;
 	}
 }