added unit test for the problem

Author: schauder

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/core/convert/MappingJdbcConverterUnitTests.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.jdbc.core.convert;
 
+import static java.util.Arrays.*;
 import static org.assertj.core.api.Assertions.*;
 import static org.assertj.core.api.SoftAssertions.*;
 import static org.mockito.Mockito.*;
@@ -40,6 +41,7 @@
 import org.junit.jupiter.api.Test;
 import org.springframework.core.convert.converter.Converter;
 import org.springframework.data.annotation.Id;
+import org.springframework.data.convert.WritingConverter;
 import org.springframework.data.jdbc.core.mapping.AggregateReference;
 import org.springframework.data.jdbc.core.mapping.JdbcMappingContext;
 import org.springframework.data.jdbc.core.mapping.JdbcValue;
@@ -70,7 +72,7 @@ class MappingJdbcConverterUnitTests {
 			(identifier, path) -> {
 				throw new UnsupportedOperationException();
 			}, //
-			new JdbcCustomConversions(), //
+			new JdbcCustomConversions(List.of(CustomIdToLong.INSTANCE)), //
 			typeFactory //
 	);
 
@@ -92,6 +94,9 @@ void testTargetTypesForPropertyType() {
 			checkTargetType(softly, entity, "date", Date.class);
 			checkTargetType(softly, entity, "timestamp", Timestamp.class);
 			checkTargetType(softly, entity, "uuid", UUID.class);
+			checkTargetType(softly, entity, "reference", Long.class);
+			checkTargetType(softly, entity, "enumIdReference", String.class);
+			checkTargetType(softly, entity, "customIdReference", Long.class);
 		});
 	}
 
@@ -234,6 +239,8 @@ private record DummyEntity(
 			Date date,
 			Timestamp timestamp,
 			AggregateReference<DummyEntity, Long> reference,
+			AggregateReference<EnumIdEntity, SomeEnum> enumIdReference,
+			AggregateReference<CustomIdEntity, SomeEnum> customIdReference,
 			UUID uuid,
 			AggregateReference<ReferencedByUuid, UUID> uuidRef,
 			Optional<UUID> optionalUuid,
@@ -255,6 +262,18 @@ private enum SomeEnum {
 	private static class OtherEntity {
 	}
 
+	private static class EnumIdEntity {
+		@Id SomeEnum id;
+	}
+
+	private static class CustomIdEntity {
+		@Id CustomId id;
+	}
+
+	private record CustomId(Long id) {
+
+	}
+
 	private static class StubbedJdbcTypeFactory implements JdbcTypeFactory {
 		Object[] arraySource;
 
@@ -284,4 +303,14 @@ public UUID convert(byte[] source) {
 			return new UUID(high, low);
 		}
 	}
+
+	@WritingConverter
+	private enum CustomIdToLong implements Converter<CustomId, Long> {
+		INSTANCE;
+
+		@Override
+		public Long convert(CustomId source) {
+			return source.id;
+		}
+	}
 }