reproduce issue and narrow down the place where the problem occurs.

See #1646

Author: schauder

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

@@ -380,6 +380,7 @@ public <T> T getPropertyValue(RelationalPersistentProperty property) {
 							aggregatePath.getRequiredPersistentPropertyPath());
 
 					if (property.isCollectionLike()) {
+						// this simply returns List, but we might expect for example a Set.
 						return (T) allByPath;
 					}
 

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

@@ -1268,6 +1268,13 @@ void multipleCollectionsWithEmptyList() {
 		assertThat(reloaded.mapElements.get("delta")).isEqualTo(new MapElement("four"));
 	}
 
+	@Test
+	void recordOfSet() {
+		Author tolkien = template.save(new Author(null, Set.of(new Book("Lord of the Rings"))));
+
+		Iterable<Author> authors = template.findAll(Author.class);
+	}
+
 	private <T extends Number> void saveAndUpdateAggregateWithVersion(VersionedAggregate aggregate,
 			Function<Number, T> toConcreteNumber) {
 		saveAndUpdateAggregateWithVersion(aggregate, toConcreteNumber, 0);
@@ -2079,6 +2086,13 @@ record SetElement(String name) {
 	record MapElement(String name) {
 	}
 
+	record Author(@Id Long id, Set<Book> books) {
+	}
+
+	record Book(String name) {
+
+	}
+
 	@Configuration
 	@Import(TestConfiguration.class)
 	static class Config {

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-hsql.sql

@@ -368,3 +368,14 @@ CREATE TABLE MAP_ELEMENT
     MULTIPLE_COLLECTIONS_KEY VARCHAR(10),
     NAME VARCHAR(100)
 );
+
+CREATE TABLE author
+(
+    ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY
+);
+
+CREATE TABLE book
+(
+    author BIGINT,
+    name varchar(100)
+);