Throw an exception for suspending factory methods

Suspending factory methods are not supported, and can
have side effects, so it is better to fail explicitly
for such use case.

Closes gh-32719

spring-beans/src/main/java/org/springframework/beans/factory/aot/InstanceSupplierCodeGenerator.java

@@ -142,7 +142,7 @@ public class InstanceSupplierCodeGenerator {
 		if (constructorOrFactoryMethod instanceof Constructor<?> constructor) {
 			return generateCodeForConstructor(registeredBean, constructor);
 		}
-		if (constructorOrFactoryMethod instanceof Method method) {
+		if (constructorOrFactoryMethod instanceof Method method && !KotlinDetector.isSuspendingFunction(method)) {
 			return generateCodeForFactoryMethod(registeredBean, method, instantiationDescriptor.targetClass());
 		}
 		throw new IllegalStateException(

spring-beans/src/main/java/org/springframework/beans/factory/support/ConstructorResolver.java

@@ -63,6 +63,7 @@ import org.springframework.beans.factory.config.DependencyDescriptor;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.config.TypedStringValue;
 import org.springframework.core.CollectionFactory;
+import org.springframework.core.KotlinDetector;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.NamedThreadLocal;
 import org.springframework.core.ParameterNameDiscoverer;
@@ -623,6 +624,11 @@ class ConstructorResolver {
 						"Invalid factory method '" + mbd.getFactoryMethodName() + "' on class [" +
 						factoryClass.getName() + "]: needs to have a non-void return type!");
 			}
+			else if (KotlinDetector.isKotlinPresent() && KotlinDetector.isSuspendingFunction(factoryMethodToUse)) {
+				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
+						"Invalid factory method '" + mbd.getFactoryMethodName() + "' on class [" +
+								factoryClass.getName() + "]: suspending functions are not supported!");
+			}
 			else if (ambiguousFactoryMethods != null) {
 				throw new BeanCreationException(mbd.getResourceDescription(), beanName,
 						"Ambiguous factory method matches found on class [" + factoryClass.getName() + "] " +

spring-beans/src/test/kotlin/org/springframework/beans/factory/aot/InstanceSupplierCodeGeneratorKotlinTests.kt

@@ -22,10 +22,8 @@ import org.junit.jupiter.api.Test
 import org.springframework.aot.hint.*
 import org.springframework.aot.test.generate.TestGenerationContext
 import org.springframework.beans.factory.config.BeanDefinition
-import org.springframework.beans.factory.support.DefaultListableBeanFactory
-import org.springframework.beans.factory.support.InstanceSupplier
-import org.springframework.beans.factory.support.RegisteredBean
-import org.springframework.beans.factory.support.RootBeanDefinition
+import org.springframework.beans.factory.support.*
+import org.springframework.beans.testfixture.beans.KotlinConfiguration
 import org.springframework.beans.testfixture.beans.KotlinTestBean
 import org.springframework.beans.testfixture.beans.KotlinTestBeanWithOptionalParameter
 import org.springframework.beans.testfixture.beans.factory.aot.DeferredTypeBuilder
@@ -47,6 +45,8 @@ class InstanceSupplierCodeGeneratorKotlinTests {
 
     private val generationContext = TestGenerationContext()
 
+	private val beanFactory = DefaultListableBeanFactory()
+
     @Test
     fun generateWhenHasDefaultConstructor() {
         val beanDefinition: BeanDefinition = RootBeanDefinition(KotlinTestBean::class.java)
@@ -74,6 +74,39 @@ class InstanceSupplierCodeGeneratorKotlinTests {
             .satisfies(hasMemberCategory(MemberCategory.INVOKE_DECLARED_CONSTRUCTORS))
     }
 
+	@Test
+	fun generateWhenHasFactoryMethodWithNoArg() {
+		val beanDefinition = BeanDefinitionBuilder
+			.rootBeanDefinition(String::class.java)
+			.setFactoryMethodOnBean("stringBean", "config").beanDefinition
+		this.beanFactory.registerBeanDefinition("config", BeanDefinitionBuilder
+				.genericBeanDefinition(KotlinConfiguration::class.java).beanDefinition
+		)
+		compile(beanFactory, beanDefinition) { instanceSupplier, compiled ->
+			val bean = getBean<String>(beanFactory, beanDefinition, instanceSupplier)
+			Assertions.assertThat(bean).isInstanceOf(String::class.java)
+			Assertions.assertThat(bean).isEqualTo("Hello")
+			Assertions.assertThat(compiled.sourceFile).contains(
+				"getBeanFactory().getBean(KotlinConfiguration.class).stringBean()"
+			)
+		}
+		Assertions.assertThat<TypeHint?>(getReflectionHints().getTypeHint(KotlinConfiguration::class.java))
+			.satisfies(hasMethodWithMode(ExecutableMode.INTROSPECT))
+	}
+
+	@Test
+	fun generateWhenHasSuspendingFactoryMethod() {
+		val beanDefinition = BeanDefinitionBuilder
+			.rootBeanDefinition(String::class.java)
+			.setFactoryMethodOnBean("suspendingStringBean", "config").beanDefinition
+		this.beanFactory.registerBeanDefinition("config", BeanDefinitionBuilder
+				.genericBeanDefinition(KotlinConfiguration::class.java).beanDefinition
+		)
+		Assertions.assertThatIllegalStateException().isThrownBy {
+			compile(beanFactory, beanDefinition) { _, _  -> }
+		}
+	}
+
     private fun getReflectionHints(): ReflectionHints {
         return generationContext.runtimeHints.reflection()
     }
@@ -96,6 +129,12 @@ class InstanceSupplierCodeGeneratorKotlinTests {
         }
     }
 
+	private fun hasMethodWithMode(mode: ExecutableMode): ThrowingConsumer<TypeHint> {
+		return ThrowingConsumer { hint: TypeHint ->
+			Assertions.assertThat(hint.methods()).anySatisfy(hasMode(mode))
+		}
+	}
+
     @Suppress("UNCHECKED_CAST")
     private fun <T> getBean(beanFactory: DefaultListableBeanFactory, beanDefinition: BeanDefinition,
                             instanceSupplier: InstanceSupplier<*>): T {

spring-beans/src/test/kotlin/org/springframework/beans/factory/support/ConstructorResolverKotlinTests.kt

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.support
+
+import org.assertj.core.api.Assertions
+import org.junit.jupiter.api.Test
+import org.springframework.beans.BeanWrapper
+import org.springframework.beans.factory.BeanCreationException
+import org.springframework.beans.factory.config.BeanDefinition
+import org.springframework.beans.testfixture.beans.factory.generator.factory.KotlinFactory
+
+class ConstructorResolverKotlinTests {
+
+	@Test
+	fun instantiateBeanInstanceWithBeanClassAndFactoryMethodName() {
+		val beanFactory = DefaultListableBeanFactory()
+		val beanDefinition: BeanDefinition = BeanDefinitionBuilder
+			.rootBeanDefinition(KotlinFactory::class.java).setFactoryMethod("create")
+			.beanDefinition
+		val beanWrapper = instantiate(beanFactory, beanDefinition)
+		Assertions.assertThat(beanWrapper.wrappedInstance).isEqualTo("test")
+	}
+
+	@Test
+	fun instantiateBeanInstanceWithBeanClassAndSuspendingFactoryMethodName() {
+		val beanFactory = DefaultListableBeanFactory()
+		val beanDefinition: BeanDefinition = BeanDefinitionBuilder
+			.rootBeanDefinition(KotlinFactory::class.java).setFactoryMethod("suspendingCreate")
+			.beanDefinition
+		Assertions.assertThatThrownBy { instantiate(beanFactory, beanDefinition, null) }
+			.isInstanceOf(BeanCreationException::class.java)
+			.hasMessageContaining("suspending functions are not supported")
+
+	}
+
+	private fun instantiate(beanFactory: DefaultListableBeanFactory, beanDefinition: BeanDefinition,
+							vararg explicitArgs: Any?): BeanWrapper {
+		return ConstructorResolver(beanFactory)
+			.instantiateUsingFactoryMethod("testBean", (beanDefinition as RootBeanDefinition), explicitArgs)
+	}
+}

spring-beans/src/testFixtures/kotlin/org/springframework/beans/testfixture/beans/KotlinConfiguration.kt

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.testfixture.beans
+
+class KotlinConfiguration {
+
+	fun stringBean(): String {
+		return "Hello"
+	}
+
+	suspend fun suspendingStringBean(): String {
+		return "Hello"
+	}
+}

spring-beans/src/testFixtures/kotlin/org/springframework/beans/testfixture/beans/factory/generator/factory/KotlinFactory.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2002-2024 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.testfixture.beans.factory.generator.factory
+
+class KotlinFactory {
+
+	companion object {
+
+		@JvmStatic
+		fun create() = "test"
+
+		@JvmStatic
+		suspend fun suspendingCreate() = "test"
+	}
+}