Consider @bean methods with args to determine type created by factory

Previously, BeanTypeRegistry would only look for a @bean method
with no arguments when trying to determine the type that will be
created by a factory bean. This meant that the type produced by a
factory bean declared via a @bean that has one or more arguments would
be unknown and any on missing bean conditions look for a bean of the
type produced by the factory bean would match in error.

This commit updates BeanTypeRegistry to, where possible, use the
factory method metadata for the bean definition when determining the
type that will be created. This allows it to determine the type for
factory bean created by @bean methods that take arguments and also
avoids the use reflection to find the factory method. Where factory
method metadata is not available, the existing reflection-based
approach is used as a fallback.

Closes gh-3657

Author: wilkinsona

spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/condition/BeanTypeRegistry.java

@@ -33,11 +33,14 @@
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.SmartInitializingSingleton;
+import org.springframework.beans.factory.annotation.AnnotatedBeanDefinition;
 import org.springframework.beans.factory.config.BeanDefinition;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.beans.factory.support.DefaultListableBeanFactory;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.core.ResolvableType;
+import org.springframework.core.type.MethodMetadata;
+import org.springframework.core.type.StandardMethodMetadata;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 import org.springframework.util.StringUtils;
@@ -108,12 +111,7 @@ private Class<?> doGetFactoryBeanGeneric(ConfigurableListableBeanFactory beanFac
 	private Class<?> getConfigurationClassFactoryBeanGeneric(
 			ConfigurableListableBeanFactory beanFactory, BeanDefinition definition,
 			String name) throws Exception {
-		BeanDefinition factoryDefinition = beanFactory.getBeanDefinition(definition
-				.getFactoryBeanName());
-		Class<?> factoryClass = ClassUtils.forName(factoryDefinition.getBeanClassName(),
-				beanFactory.getBeanClassLoader());
-		Method method = ReflectionUtils.findMethod(factoryClass,
-				definition.getFactoryMethodName());
+		Method method = getFactoryMethod(beanFactory, definition);
 		Class<?> generic = ResolvableType.forMethodReturnType(method)
 				.as(FactoryBean.class).resolveGeneric();
 		if ((generic == null || generic.equals(Object.class))
@@ -124,6 +122,24 @@ private Class<?> getConfigurationClassFactoryBeanGeneric(
 		return generic;
 	}
 
+	private Method getFactoryMethod(ConfigurableListableBeanFactory beanFactory,
+			BeanDefinition definition) throws Exception {
+		if (definition instanceof AnnotatedBeanDefinition) {
+			MethodMetadata factoryMethodMetadata = ((AnnotatedBeanDefinition) definition)
+					.getFactoryMethodMetadata();
+			if (factoryMethodMetadata instanceof StandardMethodMetadata) {
+				return ((StandardMethodMetadata) factoryMethodMetadata)
+						.getIntrospectedMethod();
+			}
+		}
+		BeanDefinition factoryDefinition = beanFactory.getBeanDefinition(definition
+				.getFactoryBeanName());
+		Class<?> factoryClass = ClassUtils.forName(factoryDefinition.getBeanClassName(),
+				beanFactory.getBeanClassLoader());
+		return ReflectionUtils
+				.findMethod(factoryClass, definition.getFactoryMethodName());
+	}
+
 	private Class<?> getDirectFactoryBeanGeneric(
 			ConfigurableListableBeanFactory beanFactory, BeanDefinition definition,
 			String name) throws ClassNotFoundException, LinkageError {

spring-boot-autoconfigure/src/test/java/org/springframework/boot/autoconfigure/condition/ConditionalOnMissingBeanTests.java

@@ -18,9 +18,11 @@
 
 import org.junit.Test;
 import org.springframework.beans.factory.FactoryBean;
+import org.springframework.beans.factory.annotation.Value;
 import org.springframework.beans.factory.support.BeanDefinitionBuilder;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.boot.autoconfigure.PropertyPlaceholderAutoConfiguration;
+import org.springframework.boot.test.EnvironmentTestUtils;
 import org.springframework.context.annotation.AnnotationConfigApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
@@ -127,6 +129,17 @@ public void testOnMissingBeanConditionWithFactoryBean() {
 				equalTo("fromFactory"));
 	}
 
+	@Test
+	public void testOnMissingBeanConditionWithFactoryBeanWithBeanMethodArguments() {
+		this.context.register(FactoryBeanWithBeanMethodArgumentsConfiguration.class,
+				ConditionalOnFactoryBean.class,
+				PropertyPlaceholderAutoConfiguration.class);
+		EnvironmentTestUtils.addEnvironment(this.context, "theValue:foo");
+		this.context.refresh();
+		assertThat(this.context.getBean(ExampleBean.class).toString(),
+				equalTo("fromFactory"));
+	}
+
 	@Test
 	public void testOnMissingBeanConditionWithConcreteFactoryBean() {
 		this.context.register(ConcreteFactoryBeanConfiguration.class,
@@ -227,6 +240,15 @@ public FactoryBean<ExampleBean> exampleBeanFactoryBean() {
 		}
 	}
 
+	@Configuration
+	protected static class FactoryBeanWithBeanMethodArgumentsConfiguration {
+		@Bean
+		public FactoryBean<ExampleBean> exampleBeanFactoryBean(
+				@Value("${theValue}") String value) {
+			return new ExampleFactoryBean(value);
+		}
+	}
+
 	@Configuration
 	protected static class ConcreteFactoryBeanConfiguration {
 		@Bean