Add AOT support for Streamable wrapper support.

We now support streamable wrappers through AOT repositories.

See #2175

Author: mp911de

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/repository/aot/JdbcCodeBlocks.java

@@ -32,6 +32,8 @@
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.core.annotation.MergedAnnotation;
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.data.domain.SliceImpl;
 import org.springframework.data.domain.Sort;
 import org.springframework.data.javapoet.LordOfTheStrings;
@@ -812,11 +814,22 @@ private CodeBlock select(ExecutionDecorator decorator, String rowMapper, String
 					return builder.build();
 				}
 
-				if (methodReturn.toClass().equals(Streamable.class)) {
+				if (isStreamable(methodReturn)) {
 					builder.addStatement(
 							"return ($1T) $1T.of(($2T) convertMany($3L, %s))".formatted(dynamicProjection ? "$4L" : "$4T.class"),
 							Streamable.class, Iterable.class, result, queryResultTypeRef);
+				} else if (isStreamableWrapper(methodReturn) && canConvert(Streamable.class, methodReturn)) {
+
+					builder.addStatement(
+							"$1T $2L = ($1T) convertMany($3L, %s)".formatted(dynamicProjection ? "$4L" : "$4T.class"), Iterable.class,
+							context.localVariable("converted"), result, queryResultTypeRef);
+
+					builder.addStatement(
+							"return ($1T) $2T.getSharedInstance().convert($3T.of($4L), $5T.valueOf($3T.class), $5T.valueOf($1T.class))",
+							methodReturn.toClass(), DefaultConversionService.class, Streamable.class,
+							context.localVariable("converted"), TypeDescriptor.class);
 				} else {
+
 					builder.addStatement("return ($T) convertMany($L, %s)".formatted(dynamicProjection ? "$L" : "$T.class"),
 							methodReturn.getTypeName(), result, queryResultTypeRef);
 				}
@@ -843,6 +856,18 @@ private CodeBlock select(ExecutionDecorator decorator, String rowMapper, String
 			return builder.build();
 		}
 
+		private boolean canConvert(Class<?> from, MethodReturn methodReturn) {
+			return DefaultConversionService.getSharedInstance().canConvert(from, methodReturn.toClass());
+		}
+
+		private static boolean isStreamable(MethodReturn methodReturn) {
+			return methodReturn.toClass().equals(Streamable.class);
+		}
+
+		private static boolean isStreamableWrapper(MethodReturn methodReturn) {
+			return !isStreamable(methodReturn) && Streamable.class.isAssignableFrom(methodReturn.toClass());
+		}
+
 		public static boolean returnsModifying(Class<?> returnType) {
 
 			return ClassUtils.resolvePrimitiveIfNecessary(returnType) == Integer.class

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/repository/JdbcRepositoryIntegrationTests.java

@@ -30,6 +30,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Iterator;
 import java.util.List;
 import java.util.Objects;
 import java.util.Optional;
@@ -603,6 +604,16 @@ public void sliceByNameShouldReturnCorrectResult() {
 		assertThat(slice.hasNext()).isTrue();
 	}
 
+	@Test // GH-2175
+	public void streamableWrapperByNameShouldReturnCorrectResult() {
+
+		repository.saveAll(Arrays.asList(new DummyEntity("a1"), new DummyEntity("a2"), new DummyEntity("a3")));
+
+		DummyEntities entities = repository.findEntitiesByNameContains("a", Limit.of(5));
+
+		assertThat(entities).hasSize(3);
+	}
+
 	@Test // GH-935
 	public void queryByOffsetDateTime() {
 
@@ -1585,6 +1596,8 @@ public interface DummyEntityRepository
 
 		Slice<DummyEntity> findSliceByNameContains(String name, Pageable pageable);
 
+		DummyEntities findEntitiesByNameContains(String name, Limit limit);
+
 		@Query("SELECT * FROM DUMMY_ENTITY WHERE OFFSET_DATE_TIME > :threshhold")
 		List<DummyEntity> findByOffsetDateTime(@Param("threshhold") OffsetDateTime threshhold);
 
@@ -1620,6 +1633,7 @@ public interface DummyEntityRepository
 
 		@Query("SELECT * FROM DUMMY_ENTITY WHERE BYTES = :bytes")
 		List<DummyEntity> findByBytes(byte[] bytes);
+
 	}
 
 	public interface RootRepository extends ListCrudRepository<Root, Long> {
@@ -2002,6 +2016,20 @@ public boolean isNew() {
 		}
 	}
 
+	public static class DummyEntities implements Streamable<DummyEntity> {
+
+		private final Streamable<DummyEntity> delegate;
+
+		public DummyEntities(Streamable<DummyEntity> delegate) {
+			this.delegate = delegate;
+		}
+
+		@Override
+		public Iterator<DummyEntity> iterator() {
+			return delegate.iterator();
+		}
+	}
+
 	public static class DummyEntity {
 
 		@Id Long idProp;