Default spring.aot.repositories.enabled to true when AOT is active

pom.xml

@@ -37,6 +37,7 @@
 		<h2>2.3.232</h2>
 		<jakarta-persistence-api>3.2.0</jakarta-persistence-api>
 		<jsqlparser>5.2</jsqlparser>
+		<junit-pioneer>2.3.0</junit-pioneer>
 		<mysql-connector-java>9.2.0</mysql-connector-java>
 		<postgresql>42.7.5</postgresql>
 		<oracle>23.8.0.25.04</oracle>
@@ -183,6 +184,12 @@
 				<type>pom</type>
 				<scope>import</scope>
 			</dependency>
+			<dependency>
+				<groupId>org.junit-pioneer</groupId>
+				<artifactId>junit-pioneer</artifactId>
+				<version>${junit-pioneer}</version>
+				<scope>test</scope>
+			</dependency>
 		</dependencies>
 	</dependencyManagement>
 

spring-data-jpa/pom.xml

@@ -100,6 +100,12 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>org.junit-pioneer</groupId>
+			<artifactId>junit-pioneer</artifactId>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework</groupId>
 			<artifactId>spring-core-test</artifactId>

spring-data-jpa/src/main/java/org/springframework/data/jpa/repository/config/JpaRepositoryConfigExtension.java

@@ -39,6 +39,7 @@
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import org.springframework.aot.AotDetector;
 import org.springframework.aot.generate.GenerationContext;
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.beans.factory.aot.BeanRegistrationAotProcessor;
@@ -87,6 +88,7 @@
  * @author Thomas Darimont
  * @author Christoph Strobl
  * @author Mark Paluch
+ * @author Hyunsang Han
  */
 public class JpaRepositoryConfigExtension extends RepositoryConfigurationExtensionSupport {
 
@@ -338,8 +340,10 @@ public static class JpaRepositoryRegistrationAotProcessor extends RepositoryRegi
 
 			Environment environment = repositoryContext.getEnvironment();
 
+			String enabledByDefault = AotDetector.useGeneratedArtifacts() ? "true" : "false";
+
 			boolean enabled = Boolean
-					.parseBoolean(environment.getProperty(AotContext.GENERATED_REPOSITORIES_ENABLED, "false"));
+					.parseBoolean(environment.getProperty(AotContext.GENERATED_REPOSITORIES_ENABLED, enabledByDefault));
 			if (!enabled) {
 				return null;
 			}

spring-data-jpa/src/test/java/org/springframework/data/jpa/repository/config/JpaRepositoryRegistrationAotProcessorUnitTests.java

@@ -30,6 +30,9 @@
 import org.jspecify.annotations.Nullable;
 import org.junit.jupiter.api.Test;
 
+import org.junitpioneer.jupiter.ClearSystemProperty;
+import org.junitpioneer.jupiter.SetSystemProperty;
+import org.springframework.aot.AotDetector;
 import org.springframework.aot.generate.ClassNameGenerator;
 import org.springframework.aot.generate.DefaultGenerationContext;
 import org.springframework.aot.generate.GenerationContext;
@@ -56,14 +59,14 @@
 
 /**
  * @author Christoph Strobl
+ * @author Hyunsang Han
  */
 class JpaRepositoryRegistrationAotProcessorUnitTests {
 
 	@Test // GH-2628
 	void aotProcessorMustNotRegisterDomainTypes() {
 
-		GenerationContext ctx = new DefaultGenerationContext(new ClassNameGenerator(ClassName.OBJECT),
-				new InMemoryGeneratedFiles());
+		GenerationContext ctx = createGenerationContext();
 
 		new JpaRepositoryConfigExtension.JpaRepositoryRegistrationAotProcessor()
 				.contribute(new DummyAotRepositoryContext(null) {
@@ -79,8 +82,7 @@ public Set<Class<?>> getResolvedTypes() {
 	@Test // GH-2628
 	void aotProcessorMustNotRegisterAnnotations() {
 
-		GenerationContext ctx = new DefaultGenerationContext(new ClassNameGenerator(ClassName.OBJECT),
-				new InMemoryGeneratedFiles());
+		GenerationContext ctx = createGenerationContext();
 
 		new JpaRepositoryConfigExtension.JpaRepositoryRegistrationAotProcessor()
 				.contribute(new DummyAotRepositoryContext(null) {
@@ -99,8 +101,7 @@ public Set<MergedAnnotation<Annotation>> getResolvedAnnotations() {
 	@Test // GH-3838
 	void repositoryProcessorShouldConsiderPersistenceManagedTypes() {
 
-		GenerationContext ctx = new DefaultGenerationContext(new ClassNameGenerator(ClassName.OBJECT),
-				new InMemoryGeneratedFiles());
+		GenerationContext ctx = createGenerationContext();
 
 		GenericApplicationContext context = new GenericApplicationContext();
 		context.registerBean(PersistenceManagedTypes.class, () -> {
@@ -126,12 +127,83 @@ public List<String> getManagedPackages() {
 		context.getEnvironment().getPropertySources()
 				.addFirst(new MockPropertySource().withProperty(AotContext.GENERATED_REPOSITORIES_ENABLED, "true"));
 
-		JpaRepositoryContributor contributor = new JpaRepositoryConfigExtension.JpaRepositoryRegistrationAotProcessor()
-				.contribute(new DummyAotRepositoryContext(context), ctx);
+		JpaRepositoryContributor contributor = createContributor(new DummyAotRepositoryContext(context), ctx);
 
 		assertThat(contributor.getMetamodel().managedType(Person.class)).isNotNull();
 	}
 
+	@Test // GH-3899
+	@SetSystemProperty(key = AotDetector.AOT_ENABLED, value = "true")
+	void repositoryProcessorShouldEnableAotRepositoriesByDefaultWhenAotIsEnabled() {
+
+		GenerationContext ctx = createGenerationContext();
+		GenericApplicationContext context = createApplicationContext();
+
+		JpaRepositoryContributor contributor = createContributorWithPersonTypes(context, ctx);
+
+		assertThat(contributor).isNotNull();
+	}
+
+	@Test // GH-3899
+	@ClearSystemProperty(key = AotDetector.AOT_ENABLED)
+	void repositoryProcessorShouldNotEnableAotRepositoriesByDefaultWhenAotIsDisabled() {
+
+		GenerationContext ctx = createGenerationContext();
+		GenericApplicationContext context = createApplicationContext();
+
+		JpaRepositoryContributor contributor = createContributorWithPersonTypes(context, ctx);
+
+		assertThat(contributor).isNull();
+	}
+
+	@Test // GH-3899
+	@SetSystemProperty(key = AotDetector.AOT_ENABLED, value = "true")
+	@SetSystemProperty(key = AotContext.GENERATED_REPOSITORIES_ENABLED, value = "false")
+	void repositoryProcessorShouldRespectExplicitRepositoryEnabledProperty() {
+
+		GenerationContext ctx = createGenerationContext();
+		GenericApplicationContext context = createApplicationContext();
+
+		JpaRepositoryContributor contributor = createContributorWithPersonTypes(context, ctx);
+
+		assertThat(contributor).isNull();
+	}
+
+	@Test // GH-3899
+	@SetSystemProperty(key = AotContext.GENERATED_REPOSITORIES_ENABLED, value = "true")
+	void repositoryProcessorShouldEnableWhenExplicitlySetToTrue() {
+
+		GenerationContext ctx = createGenerationContext();
+		GenericApplicationContext context = createApplicationContext();
+
+		JpaRepositoryContributor contributor = createContributorWithPersonTypes(context, ctx);
+
+		assertThat(contributor).isNotNull();
+	}
+
+	private GenerationContext createGenerationContext() {
+		return new DefaultGenerationContext(new ClassNameGenerator(ClassName.OBJECT),
+				new InMemoryGeneratedFiles());
+	}
+
+	private GenericApplicationContext createApplicationContext() {
+		return new GenericApplicationContext();
+	}
+
+	private JpaRepositoryContributor createContributor(AotRepositoryContext repositoryContext, GenerationContext ctx) {
+		return new JpaRepositoryConfigExtension.JpaRepositoryRegistrationAotProcessor()
+				.contribute(repositoryContext, ctx);
+	}
+
+	private JpaRepositoryContributor createContributorWithPersonTypes(GenericApplicationContext context, GenerationContext ctx) {
+		return createContributor(new DummyAotRepositoryContext(context) {
+			@Override
+			public Set<Class<?>> getResolvedTypes() {
+				return Collections.singleton(Person.class);
+			}
+		}, ctx);
+	}
+
 	@Entity
 	static class Person {
 		@Id Long id;

src/main/antora/modules/ROOT/pages/jpa/aot.adoc

@@ -44,7 +44,12 @@ Do not use them directly in your code as generation and implementation details m
 === Running with AOT Repositories
 
 AOT is a mandatory step to transform a Spring application to a native executable, so it is automatically enabled when running in this mode.
-It is also possible to use those optimizations on the JVM by setting the `spring.aot.enabled` and `spring.aot.repositories.enabled` properties to `true`.
+When AOT is enabled (either for native compilation or by setting `spring.aot.enabled=true`), AOT repositories are automatically enabled by default.
+
+You can explicitly control AOT repository generation by setting the `spring.aot.repositories.enabled` property:
+
+* `spring.aot.repositories.enabled=true` - Explicitly enable AOT repositories
+* `spring.aot.repositories.enabled=false` - Disable AOT repositories even when AOT is enabled
 
 AOT repositories contribute configuration changes to the actual repository bean registration to register the generated repository fragment.