Fix problems with reading converters.

Let the AggregateReference converters now receive also custom converters as delegates.
Remove the ArrayToObjectConverter which just uses the first element of the array from the DefaultConversion service.

Closes #1750

Author: schauder

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/JdbcCustomConversions.java

@@ -20,7 +20,7 @@
 import java.util.Collections;
 import java.util.List;
 
-import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.converter.Converter;
 import org.springframework.core.convert.converter.GenericConverter.ConvertiblePair;
 import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.data.convert.CustomConversions;
@@ -70,11 +70,33 @@ public JdbcCustomConversions() {
 	 */
 	public JdbcCustomConversions(List<?> converters) {
 
-		super(new ConverterConfiguration( //
-				STORE_CONVERSIONS, //
+		super(constructConverterConfiguration(converters));
+	}
+
+	private static ConverterConfiguration constructConverterConfiguration(List<?> converters) {
+
+		StoreConversions storeConversions = storeConversions(converters);
+
+		return new ConverterConfiguration( //
+				storeConversions, //
 				converters, //
 				JdbcCustomConversions::excludeConversionsBetweenDateAndJsr310Types //
-		));
+		);
+	}
+
+	private static StoreConversions storeConversions(List<?> userConverters) {
+
+		List<Object> converters = new ArrayList<>(Jsr310TimestampBasedConverters.getConvertersToRegister());
+
+		DefaultConversionService defaultConversionService = new DefaultConversionService();
+		for (Object userConverter : userConverters) {
+			if (userConverter instanceof Converter<?, ?> converter)
+				defaultConversionService.addConverter(converter);
+		}
+
+		converters.addAll(AggregateReferenceConverters.getConvertersToRegister(defaultConversionService));
+
+		return StoreConversions.of(JdbcSimpleTypes.HOLDER, Collections.unmodifiableCollection(converters));
 	}
 
 	/**

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

@@ -19,6 +19,7 @@
 import static org.assertj.core.api.SoftAssertions.*;
 import static org.mockito.Mockito.*;
 
+import java.nio.ByteBuffer;
 import java.sql.Array;
 import java.sql.Timestamp;
 import java.time.Instant;
@@ -28,13 +29,15 @@
 import java.time.OffsetDateTime;
 import java.time.ZoneOffset;
 import java.time.ZonedDateTime;
+import java.util.Collections;
 import java.util.Date;
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
 
 import org.assertj.core.api.SoftAssertions;
 import org.junit.jupiter.api.Test;
+import org.springframework.core.convert.converter.Converter;
 import org.springframework.data.annotation.Id;
 import org.springframework.data.jdbc.core.mapping.AggregateReference;
 import org.springframework.data.jdbc.core.mapping.JdbcMappingContext;
@@ -50,9 +53,14 @@
  * Unit tests for {@link MappingJdbcConverter}.
  *
  * @author Mark Paluch
+ * @author Jens Schauder
  */
 public class MappingJdbcConverterUnitTests {
 
+	public static final UUID UUID = java.util.UUID.fromString("87a48aa8-a071-705e-54a9-e52fe3a012f1");
+	public static final byte[] BYTES_REPRESENTING_UUID = { -121, -92, -118, -88, -96, 113, 112, 94, 84, -87, -27, 47, -29,
+			-96, 18, -15 };
+
 	JdbcMappingContext context = new JdbcMappingContext();
 	StubbedJdbcTypeFactory typeFactory = new StubbedJdbcTypeFactory();
 	MappingJdbcConverter converter = new MappingJdbcConverter( //
@@ -61,7 +69,7 @@ public class MappingJdbcConverterUnitTests {
 				throw new UnsupportedOperationException();
 			}, //
 			new JdbcCustomConversions(), //
-			typeFactory  //
+			typeFactory //
 	);
 
 	@Test // DATAJDBC-104, DATAJDBC-1384
@@ -152,6 +160,38 @@ void accessesCorrectValuesForOneToOneRelationshipWithIdenticallyNamedIdPropertie
 		assertThat(result).isEqualTo(new WithOneToOne("one", new Referenced(23L)));
 	}
 
+	@Test // GH-1750
+	void readByteArrayToAggregateReferenceWithCustomConverter() {
+
+		JdbcMappingContext context = new JdbcMappingContext();
+		StubbedJdbcTypeFactory typeFactory = new StubbedJdbcTypeFactory();
+		Converter<byte[], UUID> customConverter = new ByteArrayToUuid();
+		MappingJdbcConverter converter = new MappingJdbcConverter( //
+				context, //
+				(identifier, path) -> {
+					throw new UnsupportedOperationException();
+				}, //
+				new JdbcCustomConversions(Collections.singletonList(customConverter)), //
+				typeFactory //
+		);
+
+		SoftAssertions.assertSoftly(softly -> {
+			checkReadConversion(softly, converter, "uuidRef", AggregateReference.to(UUID));
+			checkReadConversion(softly, converter, "uuid", UUID);
+		});
+
+	}
+
+	private static void checkReadConversion(SoftAssertions softly, MappingJdbcConverter converter, String propertyName,
+			Object expected) {
+
+		RelationalPersistentProperty property = converter.getMappingContext().getRequiredPersistentEntity(DummyEntity.class)
+				.getRequiredPersistentProperty(propertyName);
+		Object value = converter.readValue(BYTES_REPRESENTING_UUID, property.getTypeInformation() //
+		);
+
+		softly.assertThat(value).isEqualTo(expected);
+	}
 
 	private void checkConversionToTimestampAndBack(SoftAssertions softly, RelationalPersistentEntity<?> persistentEntity,
 			String propertyName, Object value) {
@@ -187,6 +227,7 @@ private static class DummyEntity {
 		private final Timestamp timestamp;
 		private final AggregateReference<DummyEntity, Long> reference;
 		private final UUID uuid;
+		private final AggregateReference<ReferencedByUuid, UUID> uuidRef;
 
 		// DATAJDBC-259
 		private final List<String> listOfString;
@@ -196,8 +237,9 @@ private static class DummyEntity {
 
 		private DummyEntity(Long id, SomeEnum someEnum, LocalDateTime localDateTime, LocalDate localDate,
 				LocalTime localTime, ZonedDateTime zonedDateTime, OffsetDateTime offsetDateTime, Instant instant, Date date,
-				Timestamp timestamp, AggregateReference<DummyEntity, Long> reference, UUID uuid, List<String> listOfString,
-				String[] arrayOfString, List<OtherEntity> listOfEntity, OtherEntity[] arrayOfEntity) {
+				Timestamp timestamp, AggregateReference<DummyEntity, Long> reference, UUID uuid,
+				AggregateReference<ReferencedByUuid, UUID> uuidRef, List<String> listOfString, String[] arrayOfString,
+				List<OtherEntity> listOfEntity, OtherEntity[] arrayOfEntity) {
 			this.id = id;
 			this.someEnum = someEnum;
 			this.localDateTime = localDateTime;
@@ -210,6 +252,7 @@ private DummyEntity(Long id, SomeEnum someEnum, LocalDateTime localDateTime, Loc
 			this.timestamp = timestamp;
 			this.reference = reference;
 			this.uuid = uuid;
+			this.uuidRef = uuidRef;
 			this.listOfString = listOfString;
 			this.arrayOfString = arrayOfString;
 			this.listOfEntity = listOfEntity;
@@ -299,9 +342,23 @@ public Array createArray(Object[] value) {
 		}
 	}
 
-	record WithOneToOne(@Id String id,@MappedCollection(idColumn = "renamed") Referenced referenced){}
+	record WithOneToOne(@Id String id, @MappedCollection(idColumn = "renamed") Referenced referenced) {
+	}
 
 	record Referenced(@Id Long id) {
 	}
 
+	record ReferencedByUuid(@Id UUID id) {
+	}
+
+	class ByteArrayToUuid implements Converter<byte[], UUID> {
+		@Override
+		public UUID convert(byte[] source) {
+
+			ByteBuffer byteBuffer = ByteBuffer.wrap(source);
+			long high = byteBuffer.getLong();
+			long low = byteBuffer.getLong();
+			return new UUID(high, low);
+		}
+	}
 }

spring-data-relational/src/main/java/org/springframework/data/relational/core/conversion/AbstractRelationalConverter.java

@@ -72,6 +72,8 @@ private AbstractRelationalConverter(RelationalMappingContext context, CustomConv
 		this.entityInstantiators = entityInstantiators;
 		this.conversions = conversions;
 
+		this.conversionService.removeConvertible(Object[].class, Object.class);
+
 		conversions.registerConvertersIn(this.conversionService);
 	}